The potential health effects of phthalate esters in children's toys: a review and risk assessment.

Wilkinson CF, Lamb JC 4th

Diisononyl phthalate (DINP) is one of several dialkyl phthalate esters that are widely used as plasticizers to impart softness and flexibility to normally rigid polyvinyl chloride (PVC) products. During the past 2 years, concern has been voiced by public interest groups and regulatory agencies in Europe, Canada, and the United States regarding the potential adverse health effects of DINP migrating from children's toys during mouthing activities. Concern has focused on potential chronic effects on the kidney and liver. In chronic high-dose
studies with rodents, DINP causes a dose-related decrease in body weight, an increase in liver weight, and changes in liver cell histopathology (hypertrophy). To a lesser extent, the rodent kidney is also a target for prolonged high-level exposures of DINP. Prolonged high-level exposure of rodents to DINP leads to an increased incidence of liver tumors (adenomas and carcinomas). The chronic cancer and noncancer effects of DINP on rodent liver are consistent with its known action as a peroxisome proliferator. Peroxisome proliferation is a threshold-based effect that is reversible on cessation of exposure to proliferators such as DINP. Because rodents are uniquely responsive and humans and nonhuman primates are particularly nonresponsive to peroxisome proliferators, rodents are very poor animal models for use in human risk assessment of adverse effects mediated through peroxisome proliferation. Because DINP exerts its effects on rodent liver through a known threshold-based mechanism of little, if any, relevance to humans, a highly conservative risk assessment can be conducted using a NOAEL uncertainty factor approach. Chronic rodent no-observed-effect levels (NOELs) based on end points such as increased liver weight and changes in liver pathology that are early indicators of peroxisome proliferation but should not be considered adverse range from about 100 to 400 mg/kg/day. Application of a 100-fold uncertainty factor yields acceptable daily intakes (ADIs) ranging from 1 to 4 mg/kg/day. Estimates of DINP migration from soft PVC materials have been obtained from a variety of in vitro methods (simulated saliva and controlled agitation) as well as in vivo methods (controlled chewing) that more closely resemble child chewing and mouthing activities. Recent estimates by the Consumer Product Safety Commission (CPSC)
suggest that maximum exposures occur in infants 3-12 months of age. The geometric mean (50th percentile) exposure is 5.7 microg/kg/day and the 95th percentile is 94.3 microg/kg/day. These exposure values are 17,500-70,000 and 1100-4200 times, respectively, lower than the chronic rodent NOAEL for DINP and 175-700 and 11-42 times lower than the corresponding ADI of 1-4 mg/kg/day. It is concluded, with a high degree of confidence, that the use of DINP in soft PVC toys and other children's products does not present a significant risk to children. The scientific evidence supports the continued use of DINP as a plasticizer in children's products. Copyright 1999 Academic Press.

Potential Hazards of Exposure to Di-(2-Ethylhexyl)-Phthalate in Babies. a review.

Latini G

Many plastic items are made of polyvinylchloride (PVC) blended with plasticizers. The most frequently used plasticizer is
di-(2-ethylhexyl)-phthalate (DEHP). DEHP migrates at a constant rate from plastics to the environment: it has been detected in water, soil and food and is therefore considered as a widespread environmental contaminant. Over the past several years, a number of publications concerning toxic effects of DEHP on animals and humans have been reported. Although DEHP is suggested to be of low acute toxicity, long-term exposure, especially in human beings at risk such as pregnant women and children, requires more in-depth studies. If DEHP toxicity in humans were to be confirmed, it would be advisable in the future to replace current PVC plasticizers, especially if they come into contact with babies, with better-quality materials. Copyright 2000 S. Karger AG, Basel
 

2. Consum Rep 1999 May;64(5):28-9

Baby alert. New findings about plastics: parents may want to replace some baby bottles and teethers.
 

3. Lancet 1975 May 24;1(7917):1172-3

Editorial: P.V.C., plasticisers, and the paediatrician.
 

4. Med Device Technol 1999 Jul-Aug;10(6):10-2

Bags of toys: the demise of PVC.

Williams D

Clinical Engineering Department, Royal Liverpool University Hospital, UK. dfw.ce@liverpool.ac.uk

Poly(vinyl chloride) (PVC) is a widely used commodity plastic that has many applications in medical devices. Recent concerns over the oestrogenic activity of some of the phthalate plasticizers used in PVC, and the hazards associated with dioxin that may be produced during the incineration of PVC waste have initiated an assessment of the future role of this material. This article addresses some of the underlying toxicological and risk assessment issues.
 

5. Time 1999 Mar 1;153(8):53

Poisonous plastics? Some cling wraps, children's toys and even IV bags may be carrying--and shedding--toxic chemicals.

Kluger J
 

6. Bull Environ Contam Toxicol 1998 Jan;60(1):68-73

Analysis of potentially toxic phthalate plasticizers used in toy manufacturing.

Marin ML, Lopez J, Sanchez A, Vilaplana J, Jimenez A
 

7. Ann Clin Lab Sci 1985 Mar-Apr;15(2):140-51

Bis-(2-ethylhexyl) phthalate, an ubiquitous environmental contaminant.

Griffiths WC, Camara P, Lerner KS

Bis-(2-ethylhexyl) phthalate (DEHP) is the most commonly used plasticizing agent for the widely used plastic polyvinylchloride (PVC). Consequently, this compound is found everywhere in the environment of civilization, where it is in frequent contact with every person. Blood storage bags and tubing, food wrappers, and many children's toys contain appreciable amounts of DEHP. Given this frequency of exposure, the toxic potential of the compound has become a major concern. Many workers have demonstrated its exceedingly low acute toxicity, while results from chronic exposure studies have been mixed. However, in 1982 the National Toxicology Program reported a significantly increased incidence of hepatocellular carcinoma in rats and mice exposed to high doses of DEHP over a period of two years. The significance of these studies remains in question. Bis-(2-ethylhexyl) phthalate is metabolized extensively by mammals, but reports of the direct study of the toxic effects of its metabolites are few. Efficient methods for analysis of biological samples for DEHP are available, but they are complicated by the constant presence of this compound as a contaminant.
 

8. Clin Pediatr (Phila) 1976 Dec;15(12):1107-9

A comprehensive protocol for evaluating the safety of toys for preschool children.

Southard SC, Arena JM

Vulvovaginal candidiasis in female sex workers.

Otero L, Palacio V, Carreno F, Mendez FJ, Vazquez F

Vulvovaginal candidiasis is a frequent inflammatory process in women but it has not been widely studied in female sex workers (FSWs). To estimate the frequency of Candida species infection in FSWs and to identify related risk factors and clinical findings, we carried out a retrospective study of 1923 FSWs over 11 years. We also performed a prospective study of 163 consecutive FSWs with a history of candidiasis during a 4-year period. Candida species were isolated in 1967 samples (18.5% of the total). Candida albicans (89.3%) was the most frequent species, followed by Candida glabrata (2.7%), Candida parapsilosis (1.2%) and Saccharomyces cerevisiae (0.4%). In the prospective study of 163 patients, we found vaginal discharge in 76.1% of cases, soreness in 52.1% and vulval pruritus in 32.5%. We identified 12 patients (7.4%) with recurrent vulvovaginal candidiasis. No statistical difference was found between recurrent vulvovaginitis and the use of oral contraceptives, oral sex, tight-fitting clothing and synthetic underwear. FSWs have the same prevalence of candidiasis as other groups of women described in published literature. The proportion of albicans and non-albicans species does not differ between women with recurrent and non-recurrent vulvovaginal candidiasis (VVC).
 

2. J Urol 1998 Oct;160(4):1329-33

Are boxer shorts really better? A critical analysis of the role of underwear type in male subfertility.

Munkelwitz R, Gilbert BR

PURPOSE: Elevation of testicular temperature may result in arrest of spermatogenesis, abnormal semen parameters and sterility. It has been proposed that brief style underwear may produce scrotal hyperthermia and lead to clinical subfertility. Although this idea is regarded as dogma by many in the lay community and the changing of underwear type is a therapy frequently recommended by medical practitioners, there is a paucity of data measuring scrotal temperature as a function of underwear type. MATERIALS AND METHODS: Scrotal, core and skin temperatures were measured in 97 consecutive men presenting for evaluation of primary clinical subfertility. These cases were categorized by underwear type to boxer or brief group. Semen analyses were obtained in all patients. Individuals from each group were compared to ascertain differences in temperature when wearing and not wearing underwear. Baseline semen parameters also were compared. In 14 subjects (crossover group) underwear type was changed to the alternative type and scrotal temperature measurements were repeated. Literature regarding underwear type, testicular temperature and/or fertility was reviewed and critically analyzed. RESULTS: Mean scrotal temperature plus or minus standard deviation was 33.8 +/- 0.8 C and 33.6 +/- 1.1 C in the boxer and brief group, respectively. There were no significant temperature differences between the groups. Differential temperatures comparing core to scrotal temperature and semen parameters also were not significantly different. These observations remained constant in the crossover group. CONCLUSIONS: The hyperthermic effect of brief style underwear has been exaggerated. In our study there was no difference in scrotal temperature depending on underwear type. It is unlikely that underwear type has a significant effect on male fertility. Routinely advising infertility patients to wear boxer shorts cannot be supported by available scientific evidence.

3. Eur J Obstet Gynecol Reprod Biol 1992 Jan 9;43(1):51-7

Lifestyles of men in barren couples and their relationships to sperm quality.

Oldereid NB, Rui H, Purvis K

This study is based on a questionnaire which focused on the possible association between lifestyle factors and male fertility in a group of 252 men attending our laboratory in connection with a fertility investigation. Their answers were correlated to sperm quality. No association could be documented between sperm quality and smoking habits, coffee drinking, a moderate alcohol intake, exposure to heat (sauna, hot baths, type of underwear, sedentary activities) or physical activities in their leisure time. In contrast, the reported average ejaculation frequency was significantly positively correlated to the motility of the sperm (% progressive) but inversely related to the proportion of sperm with abnormal morphology and semen volume. This indicates that the lifestyle of the subject has little, if any, impact on semen quality, at least within the limits recorded in the present study.

4.  Int J Fertil 1992 Nov-Dec;37(6):343-9
... tohle se nedá počítat jako samostatná studie, a navíc to vrhá na autory poněkud podivné světlo!

Life styles of men in barren couples and their relationship to sperm quality.

Oldereid NB, Rui H, Purvis K

This study is based on a questionnaire which focused on the possible association between life-style factors and male fertility in a group of 252 men attending our laboratory in connection with a fertility investigation. Their answers were correlated to sperm quality. No association could be documented between sperm quality and smoking habits, coffee drinking, a moderate alcohol intake, exposure to heat (sauna, hot baths, type of underwear, sedentary activities), or physical activities in their leisure time. In contrast, the reported average ejaculation frequency was significantly positively correlated to the motility of the sperm (% progressive), and inversely related to the proportion of sperm with abnormal morphology and semen volume. This indicates that the life style of the subject has little if any impact on semen quality, at least within the limits recorded in the present study.

Fit of underwear and male spermatogenesis: a pilot investigation.

Sanger WG, Friman PC

We evaluated the effect fit of underwear had on sperm production in two healthy adult males in their early thirties. The subjects alternated from wearing tight fitting bikini type briefs to loose fitting boxer type briefs in an ABAB withdrawal design. Conditions lasted three months and were alternated twice resulting in a one year study. The initial condition for each subject was randomly determined with the laboratory technologist blind to the conditions. Four semen parameters were analyzed in this study: sperm density, total number of sperm, total number of motile sperm, and total number of motile sperm per hour of abstinence. The results showed the semen parameters gradually decreased in tight conditions and gradually increased during loose conditions. Although preliminary, the results support the commonly held but undocumented belief that the fit of men's underwear can influence sperm production.
 

2. Lancet 1996 Jun 29;347(9018):1844-5

Tight-fitting underwear and sperm quality

Carolina H J Tiemessen, Johannes L H Evers, Robert S G M Bots

Sir--The optimum temperature for human spermatogenesis is 35oC. Adaptive mechanisms such as vascular counter-current heat exchange in the funiculus spermaticus and selective contraction of scrotal wall musculature allow for regulation of the testicular temperature. Scrotal hyperthermia has an impairing effect on spermatogenesis, as shown by artificial elevation of the intrascrotal temperature.1 Mieusset and co-workers have reported artificial cryptorchidism to cause significant decreases in sperm concentrations and motility.2 By their insulating effect, different types of clothing might affect deep scrotal temperature as well.3 From our infertility practice we got the impression that loose-fitting and tight-fitting underwear have a differential effect on sperm quality. To test the hypothesis that tight-fitting underwear impairs sperm quality, we embarked on a prospective randomised trial to evaluate the effect of either type of underwear on sperm concentration, motility, and progressive motility.

Healthy men of proven fertility who were between 25 and 50 years of age were eligible for the study. Semen quality was not an inclusion criterion. All volunteers had to abandon hot baths, saunas, and electric blankets for the 12-month period of the study. Semen analysis was done every 2 weeks by means of a computer assisted semen analyser (CASA; Hamilton Thorn IVOS, Hamilton Thorn, Beverly, USA) with a microcell counting chamber. Results during 6 months of wearing tight-fitting underwear for 24 hours per day were compared with those during 6 months of wearing loose underwear (boxer shorts). The order in which each type of underwear was to be worn was determined by a code in a closed envelope generated by a computerised randomisation procedure. 20 volunteers were included in the study. 11 were randomised to the sequence of wearing 6 months of loose underwear, followed by 6 months of tight-fitting underwear; the remaining nine to the tight-loose sequence. Notwithstanding an extensive informed consent procedure 11 men discontinued participation prematurely because of the inconvenience of frequent semen analyses and loss of motivation due to the long duration of the study.
 

                       Table: Median values (and ranges) of CASA semen analysis in nine fertile volunteers

Nine volunteers completed the study, six from the loose-tight and three from the tight-loose sequence. The median results per volunteer were calculated for the 6-month periods of wearing tight and loose underwear, respectively, and a comparison of paired observations per individual was done (Wilcoxon matched-pairs signed-rank test; table). The sperm concentration (p<005), the motile sperm concentration (p<0005), and the progressively motile sperm concentration (p<0005) differed significantly between the periods of wearing loose versus tight-fitting underwear.

We conclude that wearing tight-fitting underwear instead of boxer shorts impairs sperm quality.

                       We thank M F Peeters, J S E Laven, H J H M van Dessel, and
                       R F A Weber for their suggestions and criticisms.
 

3. Urol Res 1993;21(5):367-70

Effect of different types of textile fabric on spermatogenesis: an experimental study.

Shafik A

The effect of different types of textile fabric on spermatogenesis was studied. Twenty-four dogs were divided into two equal groups, one of which wore cotton underpants and the other polyester ones. Seven dogs wearing nothing were used as controls. The underwear was fashioned to fit loosely in the scrotal area so as to avoid its insulating effect. It was worn continuously for 24 months during which the semen character, testicular temperature, hormones (serum testosterone, follicle stimulating hormone, luteinizing hormone, prolactin) and testicular biopsy were examined. The garment was then removed, and the same investigations repeated through another 12 months. The results were analysed statistically. In the polyester group the testicular temperature showed insignificant changes during the period when the pants were worn (P > 0.05). By the end of the 24 months there was a significant decrease in sperm count and motile sperms, with an increase in abnormal forms (P < 0.001); the testicular biopsy showed degenerative changes. After garment removal the semen character improved gradually to normal in 10 dogs; two remained oligozoospermic. There were insignificant changes (P > 0.05) in hormones during the study. In contrast, the cotton and control groups showed insignificant changes (P > 0.05) in all the aforementioned parameters during the 36 months of the study. The polyester pants thus had a deleterious effect on spermatogenesis in the dogs which was, however, reversible in the majority of cases. The cause of this effect is unknown, but it may be assumed that the electrostatic potentials generated by the polyester fabric play a role in it.
 

4.  Arch Androl 1996 Sep-Oct;37(2):111-5

Effect of different types of textiles on male sexual activity.

Shafik A

The effect of different types of textile underpants on sexual activity was studied in 50 men. All the subjects were potent and sexually active. They were divided into 5 equal groups: 4 test and 1 control. Each of the 4 test groups were dressed in one type of textile underpants made of either 100% polyester, 50/50% polyester/cotton mix, 100% cotton, or 100% wool. Sexual behavior was assessed before and after 6 and 12 months of wearing the pants, and 6 months after their removal. Behavioral response was rated as potent if the subject's penis became erect, entered the vagina, and ejaculated. The rate of potent intromission (I) to mounts (M) (I/M ratio) was determined. The electrostatic potentials (EP) generated on the penis and scrotum were measured by an electrostatic kilovoltmeter. The I/M ratio at 6 and 12 months of wearing the polyester and polyester/cotton mix pants was significantly reduced compared to the pretest levels and the controls (p < .001). The reduction was more manifest in the pure polyester than in the polyester/cotton mix group, and at the 12-month than at the 6-month examination. The I/M ratio of the cotton and wool groups showed insignificant changes during the study period. Six months after removal of the underpants, the I/M ratio had returned to the pretest levels in the two groups that had worn polyester-containing pants. The polyester-containing pants generated EP, which may induce electrostatic fields in the intrapenile structures and could explain the diminished sexual activity. The cotton and wool textiles did not generate EP. Thus, polyester underpants could have an injurious effect on human sexual activity.
 

5: Eur Urol 1993;24(3):375-80

Effect of different types of textiles on sexual activity. Experimental study.

Shafik A

Department of Surgery and Research, Faculty of Medicine, Cairo University, Egypt.

The effect of wearing different types of textiles on sexual activity was studied in 75 rats which were divided into five equal groups: four test groups and one control. Each of the four test groups were dressed in one type of textile pants made of either 100% polyester, 50/50% polyester/cotton mix, 100% cotton or 100% wool. Sexual behaviour was assessed before and after 6 and 12 months of wearing the pants and 6 months after their removal. The rate of intromission to mounting (I/M) was determined. The electrostatic potentials generated on penis and scrotum were also measured by electrostatic kilovoltameter. At 6 and 12 months of wearing the polyester and polyester-cotton mix pants, the I/M ratio was significantly reduced compared to the pre-test levels and the controls (p < 0.0001). The reduction was more manifest in the polyester than in the polyester-cotton mix group, and at the 12th month than at the 6th month of
examination. The I/M ratio of the cotton and wool groups showed insignificant changes (p > 0.05) at the 6th month of the study and a significant increase at the 12th month (p < 0.01). Six months after removal of the pants, the I/M ratio returned to the pre-test levels (p > 0.05) in the four groups. The polyester-containing pants generated electrostatic potentials while the other textiles did not. These potentials seem to induce 'electrostatic fields' in the intrapenile structures, which could explain the decrease in the rats' sexual activity.
 

6. J Fam Pract 1984 Oct;19(4):491-4

Clothing factors and vaginitis.
Heidrich FE, Berg AO, Bergman JJ

Associations of clothing factors and vulvovaginal symptoms, signs, and microbiology were sought in 203 women seeking care at a university family medicine clinic. Clothing factors studied were use of panty hose, underwear for sleep, cotton lining panels, and pants vs skirts. Women wearing and not wearing panty hose had similar rates of vaginitis symptoms and signs, but yeast vaginitis was about three times more common among wearers. Relationships of other clothing factors to vaginitis were not found. Nonspecific vaginitis was not found to be related to clothing.

7. Am J Public Health 1983 Apr;73(4):450-2
Quantitative relationships of Candida albicans infections and dressing patterns in Nigerian women.

Elegbe IA, Elegbe I

Candida albicans colony counts were far higher in patients with vaginitis wearing tight fitting clothing than in patients wearing loose fitting clothing. In Ile-Ife, Nigeria, tight fitting dresses, woolen and corduroy jeans, coupled with nylon underwear, appear to create an environment favorable to Candida albicans colonization.

8. Arch Dermatol 1997 Apr;133(4):536-7

Leg band-limited latex dermatitis from a common method of underwear construction.

Rye B, Webb JM
 

9: Arch Dermatol 1975 May;111(5):593-5

Allergic contact dermatitis to underwear elastic. Chemically transformed by laundry bleach.

Jordan WP Jr, Bourlas MC

Six subjects, allergic to the elastic in their undergarments, were patch test-negative to the rubber components and new elastic from the suppliers. However, washing the rubber with sodium hypochlorite gave the subjects allergic responses due to the effect of bleach on the rubber accelerator, zinc dibenzyldithiocarbamate (ZDC). To identify the allergen, ZDC was reacted with the sodium hypochlorite, and the resultant gum was extracted with diethyl ether. Eight compounds were identified in the reaction mixture by gas chromatography-mass spectrometry. The individual components were tested on volunteers after sensitization to the reaction mixture was produced in 14 of 25
volunteers. One component, N,N-dibenzylcarbamyl chloride produced an allergic response in each sensitized volunteer.

10: Minerva Ginecol 1992 Sep;44(9):407-13

[Non-sexual transmission of sexually transmissible diseases].
[Article in Italian]

Broso P, Buffetti G, Sacco A

Sexually transmitted diseases can be transmitted through nonsexual transmission. Neonatal contamination has been proven at parturition from mothers with anogenital diseases. Another example is transmission through exchange of underwear, towels, bed sharing, etc. It is possible that contamination may occur with use of the contaminated speculum and forceps. Use of laser may release viruses during treatment for viral diseases. Candidiasis, trichomoniasis and genitalis condilomatosis, which should not be considered an exclusively sexually transmitted diseases are considered.

Boxer shorts, gummy bears and lasered hairs.

2. Harv Mens Health Watch 1999 Jun;3(11):8

I am 34 years old. I've been married for three years and we want to start a family. My wife wants me to switch to boxer shorts to help things along. is there anything to this theory?

Simon HB

3. Reprod Fertil Dev 1998;10(1):93-5

Are sperm counts really falling?

de Kretser DM

Semen quality is said to have been declining over the past 50 years. The biological significance of these changes is emphasized by a concomitant increase in the incidence of genitourinary abnormalities such as testicular cancer and cryptorchidism. The increase in regional frequency of testicular abnormalities over a relatively short period of time may be due to local environmental factors, including the comparatively recent fashion for wearing tight-fitting underwear. Data also indicates that prenatal exposure to environmental agents can affect the development of the male genital tract. From the reproductive point of view, an increased environmental impact on the human male gonad is of concern and merits the development of sensitive techniques that can detect deleterious agents.

Absence of toxicity of Bacillus thuringiensis pollen to black swallowtails under field conditions.

Wraight CL, Zangerl AR, Carroll MJ, Berenbaum MR

A single laboratory study on monarch butterflies has prompted widespread concern that corn pollen, engineered to express Bacillus thuringiensis (Bt) endotoxin, might travel beyond corn fields and cause mortality in nontarget lepidopterans. Among the lepidopterans at high potential risk from this technology is the black swallowtail butterfly, Papilio polyxenes, whose host plants in the midwestern U. S. are located principally in narrow strips between roads and crop fields. A field study was performed to assess whether mortality of early instar black
swallowtails was associated either with proximity to a field of Bt corn or by levels of Bt pollen deposition on host plants. Potted host plants were infested with first instar black swallowtails and placed at intervals from the edge of a field of Bt corn (Pioneer 34R07 containing Monsanto event 810) at the beginning of anthesis. We confirmed by ELISA that pollen from these plants contained Cry1Ab endotoxin (2.125 +/- 0.289 ng/g). Although many of the larvae died during the 7 days that the experiments were run, there was no relationship between
mortality and proximity to the field or pollen deposition on host plants. Moreover, pollen from these same plants failed to cause mortality in the laboratory at the highest pollen dose tested (10,000 grains/cm(2)), a level that far exceeded the highest pollen density observed in the field (200 grains/cm(2)). We conclude that Bt pollen of the variety tested is unlikely to
affect wild populations of black swallowtails. Thus, our results suggest that at least some potential nontarget effects of the use of transgenic plants may be manageable.

2.  Proc Natl Acad Sci U S A 2000 Mar 28;97(7):3724-9

Increased nutritive value of transgenic potato by expressing a nonallergenic seed albumin gene from Amaranthus hypochondriacus.

Chakraborty S, Chakraborty N, Datta A

Improvement of nutritive value of crop plants, in particular the amino acid composition, has been a major long-term goal of plant breeding programs. Toward this end, we reported earlier the cloning of the seed albumin gene AmA1 from Amaranthus hypochondriacus. The AmA1 protein is nonallergenic in nature and is rich in all essential amino acids, and the composition corresponds well with the World Health Organization standards for optimal human nutrition. In an attempt to improve the nutritional value of potato, the AmA1 coding sequence was
successfully introduced and expressed in tuber-specific and constitutive manner. There was a striking increase in the growth and production of tubers in transgenic populations and also of the total protein content with an increase in most essential amino acids. The expressed protein was localized in the cytoplasm as well as in the vacuole of transgenic tubers. Thus we have been able to use a seed albumin gene with a well-balanced amino acid composition as a donor protein to develop a transgenic crop plant. The results document, in addition to
successful nutritional improvement of potato tubers, the feasibility of genetically modifying other crop plants with novel seed protein composition.

3.  Biosci Biotechnol Biochem 1999 Nov;63(11):1942-6

Safety assessment of transgenic potatoes with soybean glycinin by feeding studies in rats.

Hashimoto W, Momma K, Yoon HJ, Ozawa S, Ohkawa Y, Ishige T, Kito M, Utsumi S, Murata K

Feeding studies of transgenic potatoes with native and designed soybean glycinins in rats were done for four weeks. The designed glycinin has four additional methioninyl residues in the middle of the glycinin molecule. Rats were divided into four groups fed (I) only a commercial diet, (II) the diet plus non-transgenic potatoes, (III) the diet plus transgenic potatoes with native glycinin, and (IV) the diet plus transgenic potatoes with designed glycinin. Rats were fed 2,000 mg/kg-weight potatoes every day by oral administration. During the period tested, rats in each group (groups II, III, and IV) grew well without marked differences in appearance, food intake, body weight, or in cumulative body weight gain. No significant differences were also found in blood count, blood composition, and in internal organ weights among the rats after feeding potatoes (groups II, III, and IV) for four weeks. Necropsy at the end of experiment indicated neither pathologic symptoms in all rats tested nor histopathological abnormalities in liver and kidney. Judging from these results, the transgenic potatoes with glycinins are confirmed to have nearly the same nutritional and biochemical characteristics as non-transgenic one.

4.  Science 2000 Jan 14;287(5451):303-5

Engineering the provitamin A (beta-carotene) biosynthetic pathway into (carotenoid-free) rice endosperm.

Ye X, Al-Babili S, Kloti A, Zhang J, Lucca P, Beyer P, Potrykus I

Rice (Oryza sativa), a major staple food, is usually milled to remove the oil-rich aleurone layer that turns rancid upon storage, especially in tropical areas. The remaining edible part of rice grains, the endosperm, lacks several essential nutrients, such as provitamin A. Thus, predominant rice consumption promotes vitamin A deficiency, a serious public health problem in at least 26 countries, including highly populated areas of Asia, Africa, and Latin America. Recombinant DNA technology was used to improve its nutritional value in this respect. A combination of transgenes enabled biosynthesis of provitamin A in the endosperm.

5.  Transgenic Res 1998 May;7(3):157-63

Biosafety of E. coli beta-glucuronidase (GUS) in plants.

Gilissen LJ, Metz PL, Stiekema WJ, Nap JP

The beta-glucuronidase (GUS) gene is to date the most frequently used reporter gene in plants. Marketing of crops containing this gene requires prior evaluation of their biosafety. To aid such evaluations of the GUS gene, irrespective of the plant into which the gene has been introduced, the ecological and toxicological aspects of the gene and gene product have been examined. GUS activity is found in many bacterial species, is common in all tissues of vertebrates and is also present in organisms of various invertebrate taxa. The transgenic GUS originates from the enterobacterial species Escherichia coli that is widespread in the vertebrate intestine, and in soil and water ecosystems. Any GUS activity added to the ecosystem through genetically modified plants will be of no or minor influence. Selective advantages to genetically modified plants that posses and express the E. coli GUS transgene are unlikely. No increase of weediness of E. coli GUS expressing crop plants, or wild relatives that might have received the transgene through outcrossing, is expected. Since E. coli GUS naturally occurs ubiquitously in the digestive tract of consumers, its presence in food and feed from genetically modified plants is unlikely to cause any harm. E. coli GUS in genetically modified plants and their products can be regarded as safe for the environment and consumers.

6: J Nutr 1999 Aug;129(8):1597-603

Expression of the insecticidal bean alpha-amylase inhibitor transgene has minimal detrimental effect on the nutritional value of peas fed to rats at 30% of the diet.

Pusztai A, Bardocz GG, Alonso R, Chrispeels MJ, Schroeder HE, Tabe LM, Higgins TJ

The effect of expression of bean alpha-amylase inhibitor (alpha-AI) transgene on the nutritional value of peas has been evaluated by pair-feeding rats diets containing transgenic or parent peas at 300 and 650 g/kg, respectively, and at 150 g protein/kg diet, supplemented with essential amino acids to target requirements. The results were also compared with the effects of diets containing lactalbumin with or without 0.9 or 2.0 mg bean alpha-AI, levels equivalent to those in transgenic pea diets. When 300 and 650 g peas/kg diet were fed, the daily intake of alpha-AI was 11.5 or 26.3 mg alpha-AI, respectively. At the 300 g/kg level, the nutritional value of the transgenic and parent line peas was not significantly different. The weight gain and tissue weights of rats fed either of the two pea diets were not significantly different from each other or from those of rats given the lactalbumin diet even when this was supplemented with 0.9 g alpha-AI/kg. The digestibilities of protein and dry matter of the pea diets were slightly but significantly lower than those of the lactalbumin diet, probably due to the presence of naturally occurring antinutrients in peas. The nutritional value of diets containing peas at the higher (650 g) inclusion level was less than that of the lactalbumin diet. However, the differences between transgenic and parent pea lines were small, possibly because neither the purified recombinant alpha-AI nor that in transgenic peas inhibited starch digestion in the rat small intestine in vivo to the same extent as did bean alpha-AI. This was the case even though both forms of alpha-AI equally inhibited alpha-amylase in vitro. Thus, this short-term study indicated that transgenic peas expressing bean alpha-AI gene could be used in rat diets at 300 g/kg level without major harmful effects on their growth, metabolism and health, raising the possibility that transgenic peas may also be used at this level in the diet of farm animals.

7. Biotechniques 2000 Oct;29(4):832-6, 838-43

Transgenic plants and biosafety: science, misconceptions and public perceptions.

Stewart CN Jr, Richards HA 4th, Halfhill MD

One usually thinks of plant biology as a non-controversial topic, but the concerns raised over the biosafety of genetically modified (GM) plants have reached disproportionate levels relative to the actual risks. While the technology of changing the genome of plants has been gradually refined and increasingly implemented, the commercialization of GM crops has exploded. Today's commercialized transgenic plants have been produced using Agrobacterium tumefaciens-mediated transformation or gene gun-mediated transformation.
Recently, incremental improvements of biotechnologies, such as the use of green fluorescent protein (GFP) as a selectable marker, have been developed. Non-transformation genetic modification technologies such as chimeraplasty will be increasingly used to more precisely modify germplasm. In spite of the increasing knowledge about genetic modification of plants, concerns over ecological and food biosafety have escalated beyond scientific rationality. While several risks associated with GM crops and foods have been identified, the popular press, spurred by colorful protest groups, has left the general public with a sense of imminent danger. Reviewed here are the risks that are currently under research. Ecological biosafety research has identified potential risks associated with certain crop/transgene combinations, such as intra- and interspecific transgene flow, persistence and the consequences of transgenes in
unintended hosts. Resistance management strategies for insect resistance transgenes and non-target effects of these genes have also been studied. Food biosafety research has focused on transgenic product toxicity and allergenicity. However, an estimated 3.5 x 10(12) transgenic plants have been grown in the U.S. in the past 12 years, with over two trillion being grown in 1999 and 2000 alone. These large numbers and the absence of any negative reports of compromised biosafety indicate that genetic modification by biotechnology poses no immediate
or significant risks and that resulting food products from GM crops are as safe as foods from conventional varieties. We are increasingly convinced that scientists have a duty to conduct objective research and to effectively communicate the results--especially those pertaining to the relative risks and potential benefits--to scientists first and then to the public. All stakeholders in the technology need more effective dialogues to better understand risks and benefits of adopting or not adopting agricultural biotechnologies.
 

2. Nature 1999 May 20;399(6733):214

Transgenic pollen harms monarch larvae.

Losey JE, Rayor LS, Carter ME

Publication Types:
Letter

DNA stability in plant tissues: implications for the possible transfer of genes from genetically modified food.

Chiter A, Forbes JM, Blair GE

The potential for transfer of antibiotic resistance genes from genetically modified (GM) plant material to microbes through genetic recombination in the human or animal gut is a consideration that has engendered caution in the use of GM foods. This study was aimed at defining the optimal physical and chemical conditions necessary to ensure sufficient fragmentation of DNA in plant tissues to a size where it would be unlikely to be stably transferred to bacterial gut microflora. The ribulose 1,5-bisphosphate carboxylase/oxygenase small subunit (Rubisco SS) genes are of similar size (approximately 1.4 kb) to transgenes present in GM plants. DNA analysis and PCR amplification of Rubisco SS genes
showed that fresh maize and maize silage contained high molecular weight DNA and intact Rubisco SS genes. Relatively high temperatures and pressurised steam were necessary to degrade fully genomic DNA and Rubisco SS genes in maize and wheat grains, the source of most animal feedstuffs. Furthermore, chemical expulsion and extrusion of oilseeds resulted in residues with completely degraded genomic DNA. These results imply that stringent conditions are needed in the processing of GM plant tissues for feedstuffs to eliminate the possibility of transmission of transgenes.

2. Proc R Soc Lond B Biol Sci 2000 Jan 22;267(1439):117-22

Gene flow in the European corn borer Ostrinia nubilalis: implications for the sustainability of transgenic insecticidal maize.

Bourguet D, Bethenod MT, Pasteur N, Viard F

Strategies proposed for delaying resistance to Bacillus thuringiensis toxins expressed by transgenic maize require intense gene flow between individuals that grew on transgenic and on normal (referred to as refuges) plants. To investigate gene flow in the European corn borer, Ostrinia nubilalis (Hubner), the genetic variability at 29 sampled sites from France was studied by comparing allozyme frequencies at six polymorphic loci. Almost no deviations from Hardy-Weinberg expectations occurred, and a high stability of allelic distribution was found
among samples collected in the same site over two or three different generations, indicating a high stability of the genetic structure over time. The overall genetic differentiation was low at the region and whole country level, suggesting a high and homogeneous gene flow. These results are discussed in relation to the sustainability of transgenic insecticidal maize.

3. J Biotechnol 2000 Jan 28;77(1):103-14

Chemical fingerprinting for the evaluation of unintended secondary metabolic changes in transgenic food crops.

Noteborn HP, Lommen A, van der Jagt RC, Weseman JM

A common element in designed guidelines for assessment of the food safety of transgenic crops is centred on a comparative analytical analysis with conventionally bred crop plants, assuming that these products have a long history of safe use (i.e. OECD-principle of substantial equivalence). In this study we examine the utility of an off-line combination of 400 MHz proton (1H)-NMR spectroscopy and liquid chromatography (LC) for the multi-component comparison of low-molecular weight compounds (i.e. chemical fingerprinting) in complex plant matrices. The developed NMR-methodology can contribute to the demonstration of substantial equivalence by its ability to compare possible compositional alterations in a novel food crop with respect to related non-transgenic reference lines. In this respect a hierarchical approach is proposed by comparing the chemical fingerprints of the transgenic crop plant to those of: (1) isogenic parental or closely related lines bred at identical and multiple sites; (2) extended ranges of commercial varieties of that plant; and (3) downstream processing effects. This is of importance to assess the likelihood that some of the statistical differences in a transgenic crop plant may be false positives due to chance alone or arose from natural genetic and/or physiologic variations.

4.  Arch Latinoam Nutr 1999 Sep;49(3 Suppl 2):47S-51S

[New alternatives in the prevention of iron deficiency. Use of genetic engineering in food modification].

[Article in Spanish]

Garcia-Casal MN

This article reviews the possible applications of new food biotechnology techniques to introduce some compounds into plants or animals. The potential for these plant modification methods has ample applications ranging from improvements in food production and development for human consumption, production of antibodies or therapeutic proteins, inclusion of nutrients to improve nutritional value of the food to production of vaccines. It must be clear though that currently the scope and consequences of such modifications are not completely clear. There is some concern about potential secondary effects and the hypothesis of the appearance of new viruses due to recombinant genetical transformations that have not been totally rejected. However the tendency is towards considering the process as safe. Finally some evidence is presented about the possibility of introducing the capacity to synthesize vitamin A in vegetables or produce rice with high content of iron as real alternatives to fight some of the nutritional deficiencies most common worldwide.

5. Rev Esp Salud Publica 2000 May-Jun;74(3):255-61

[Health risks of genetically modified foods: a literature review].

[Article in Spanish]

Domingo Roig JL, Gomez Arnaiz M

In 1999, there has been much concern on the safety of genetically modified (GM) foods, an important and complex area of safety research, which demands rigorous standards. Various groups, including consumers and environmental Non Governmental Organizations (NGO) have suggested that all GM foods should be subjected to long-term animal feeding studies before approval for human consumption. The main goal of this review has been to know which is the state-of-the art regarding to the potential adverse effects of GM foods. Two databases, MEDLINE and TOXLINE, as well as a number of URL from INTERNET were used for references. Although commentaries, general news and letters to the Editor have been frequently published in reputable journals, papers about experimental studies on the safety of GM foods are surprisingly very scant. If data on toxicological assessment of GM foods have been obtained, these have not been reported in scientific journals and subjected to the scientific judgement.