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Biomedical subjects

Richard L Berg

Publications and source records attributed to Richard L Berg.

18 recordsLinked to original sources
PubMed2006

Changing the child labor laws for agriculture: impact on injury.

OBJECTIVE: The child labor laws are intended to protect young workers from the most dangerous jobs. However, children who work on their parents' farms are exempt from these laws. We evaluated the potential for preventing the occurrence of farm injuries among children by changing the US Federal Child Labor Laws, Hazardous Occupations Orders for Agriculture. METHODS: A retrospective case series of 1193 farm injuries among children from the United States and Canada was assembled. The Hazardous Occupations Orders were systematically applied to each case. Injury preventability was estimated. RESULTS: A total of 286 (24%) cases of injury involved immediate family members engaged in farm work. Among these children, 33% of those aged younger than 16 years and 36% of those aged 16 or 17 years were performing work prohibited under the Hazardous Occupations Orders. CONCLUSIONS: Removing the family farm exemption from the Hazardous Occupations Orders and raising the age restriction for performing hazardous agricultural work from 16 to 18 years would be efficacious in preventing the most serious injuries experienced by young family farm workers. Potential reductions in injury would meet Healthy People 2010 goals for reducing traumatic injury in the agricultural sector.

Accidents, Occupational↗
PubMed2006

Fatal agricultural injuries in preschool children: risks, injury patterns and strategies for prevention.

BACKGROUND: Agricultural injuries are an important health concern for pediatric populations and particularly for children of pre school age. This study was conducted to estimate rates and determine patterns of fatal agricultural injury among young children exposed to agricultural hazards and to identify strategies to prevent such injuries. METHODS: A national case series was assembled retrospectively for the years 1990-2001. We identified children aged 1-6 years who were fatally injured during the course of agricultural work or through contact with a hazard of an agricultural worksite. Using a standardized survey instrument, we collected data from provincial coroners' and medical examiners' case files. Fatal agricultural injury rates (calculated with denominator data from the Canada Census of Agriculture) were compared with national all-cause, unintentional fatal injury rates in the general population of Canadian children during the same period (calculated with denominator data from the Canada Census of Population). RESULTS: The annual rate of fatal agricultural injury was substantially higher than that of all-cause, unintentional fatal injury among Canadian children aged 1-6 years (14.9 v. 8.7 per 100,000 person-years, respectively). Differences in risk were attributed to elevated fatal agricultural injury rates among boys. Most injuries occurred in the agricultural worksite, largely (84/115 [73%]) the result of 3 mechanisms: being run over by agricultural machinery as a bystander (29%) or as an extra rider who fell from the machine (22%), or asphyxia due to drowning (23%). Major crush injuries (of the head, chest and abdomen) and asphyxia from drowning were the most frequent mechanisms of injury. INTERPRETATION: Preschool-aged children exposed to agricultural worksites are at high risk of fatal injuries. Prevention strategies should focus on restricting children's access to these worksites. Physicians and allied health care professionals who care for rural families could take on a proactive role in communicating the nature and magnitude of these risks.

Agriculture↗
PubMed2006

Acute health events in adult patients with genetic disorders: the Marshfield Epidemiologic Study Area.

PURPOSE: We ascertained and reviewed acute health events occurring in 2003 among patients age 18 and greater with well-defined single gene, chromosomal, and selected multifactorial conditions within the Marshfield Epidemiologic Study Area. METHODS: Of 47,077 adult Marshfield Epidemiologic Study Area Central cohort members, 1,831 (3.9%) had been given at least one of 71 ICD-9 codes appropriate for genetic diagnoses of interest. Physician review narrowed this to 591 (1.3%) validated patients for the study. Of the 591, 527 (89.2%) patients registered 6,849 visits, which were manually reviewed to delineate acute, relevant health events in the urgent care and primary care provider setting. RESULTS: A total of 244 acute relevant health events among 126 patients corresponding to 58 different genetic conditions were observed. Acute relevant health events corresponded to 3.4% of the total health events in patients identified with genetic problems. Categories of genetic conditions with the highest frequencies of acute relevant health events included chromosomal and microdeletion syndromes (21.3%), hematologic disorders (11.5%), muscular dystrophies (8.6%), and connective tissue disorders (10.2%). CONCLUSIONS: These data have multiple applications and implications in addressing the natural history, long-term medical needs and financial impact of adult patients with genetic conditions.

Acute Disease↗
PubMed2005

Do parents' perceptions of risks protect children engaged in farm work?

BACKGROUND: The purpose was to describe farm parents' perceptions of risks on their farms and determine if these perceptions were associated with (1) using of the North American Guidelines for Children's Agricultural Tasks (NAGCAT) and (2) making NAGCAT-recommended changes to enhance the safety of farm work for their children. METHODS: This is a secondary analysis of data collected by telephone interview during a randomized trial that involved 450 farms in the United States and Canada. RESULTS: While 81% of farm parents perceived farming to be more dangerous than other occupations, only 66% of those parents felt that it was more dangerous for children to work on a farm than at other work. Furthermore, risk perception scores were only weakly associated with parents' use of NAGCAT and making NAGCAT-recommended safety changes. CONCLUSION: Even with voluntary safety guidelines in hand and the general perception of farming as a dangerous occupation, many farm parents were not actively using NAGCAT to reduce the exposure of their children to hazardous farm work. Together with the continuing morbidity and mortality among farm children, this suggests that voluntary guidelines alone may not be sufficient to protect children working on farms.

Accidents, Occupational↗
PubMed2005

A prospective, randomized pilot trial of model-based warfarin dose initiation using CYP2C9 genotype and clinical data.

BACKGROUND: Rapid genetic screening for cytochrome P450 (CYP) 2C9 variants may play a role in improving the efficacy and safety of warfarin in individuals with CYP2C9 variants. The feasibility of prospective CYP2C9 model-based warfarin dosing has not yet been assessed. OBJECTIVES: To evaluate the feasibility of applying a CYP2C9 gene-based warfarin dosing model in clinical practice. DESIGN: Prospective, randomized, single-blinded clinical pilot trial. SETTING: Large multispecialty group practice. PATIENTS: Candidates were recruited from a list of clinic patients eligible for warfarin initiation. This included patients with newly diagnosed thromboembolic disease or atrial arrhythmia, as well as patients anticipating elective valvuloplasty or arthroplasty. Patients who previously received warfarin were excluded. INTERVENTIONS: Subjects were randomized to receive either 1) a standard initiation dose of 5 mg warfarin/day, or 2) rapid CYP2C9 genotyping and an initiation dose determined using parameters estimated from a previously published multivariate model [including age, body size, co-morbidity (e.g., diabetes), clinical indication (e.g., valvuloplasty) and CYP2C9 genotype]. MEASUREMENTS: Primary outcome measurements were patient willingness to participate, physician willingness to refer, sample processing time, ability to administer calculated dosage and adequacy of follow-up. LIMITATIONS: This pilot trial was designed to assess the feasibility of model-based warfarin dosing. Power was insufficient for statistical comparison of adverse event rates. RESULTS: Forty-three of 117 patients had no prior warfarin treatment and were eligible. Five declined to participate. Twenty patients were randomized to a standard initiation dose of 5 mg daily. Eighteen patients were randomized to model-based dosing. All but one participant received the assigned initiation dose. Blood draw to dosage calculation time (including genotyping) required approximately 4 hours. Six adverse events occurred within the standard dosing group, and two adverse events occurred within the model-based dosing group. CONCLUSIONS: Prospective application of a multivariate CYP2C9 gene-based warfarin dosing model is feasible.

Aged↗
PubMed2005

Impact of age, CYP2C9 genotype and concomitant medication on the rate of rise for prothrombin time during the first 30 days of warfarin therapy.

OBJECTIVES: To characterize the impact of several important clinical variables on the rate of anticoagulation during warfarin initiation (i.e., the first 30 days). DESIGN: Retrospective study. SETTING: An anticoagulation service of a large horizontally integrated, multispecialty group practice in central and northern Wisconsin. PARTICIPANTS: Patients with sufficient laboratory data obtained during the initiation phase of warfarin treatment. METHODS: Patients were consented and genotyped for cytochrome P450 (CYP) 2C9 polymorphisms. Anticoagulation laboratory data were then electronically abstracted and fitted to a logistic growth model. Rate of anticoagulation was compared between groups. RESULTS: During warfarin initiation, the mean slope for rise in International Normalized Ratio (INR) of prothrombin time was significantly associated with age (p = 0.03, n = 166). Because a relationship between diabetes and warfarin dosing has been suggested previously, we assessed the impact of this comorbidity in our model as well. Diabetes showed relatively little impact, but concomitant treatment with an anti-diabetic sulfonylurea medication was associated with an increase in slope (3-fold, p < 0.05). Since this drug interaction may occur at the level of CYP2C9, we also assessed the impact of CYP2C9 genotype in our model. The impact of CYP2C9 genotype was marginally significant (p = 0.119, non-pooled dataset; p = 0.053, data pooled for CYP2C9 *2/*2, *2/*3 and *3/*3). CONCLUSIONS: Age and concomitant sulfonylurea therapy alter the rate of anticoagulation during the first 30 days of warfarin therapy.

Age Factors↗
PubMed2005

Intradiscal electrothermal annuloplasty therapy: a case series study leading to new considerations.

OBJECTIVE: To evaluate outcomes of intradiscal electrothermal annuloplasty (IDEA) therapy in the treatment of chronic discogenic low back pain in consecutive IDEA patients treated at a rural pain management clinic. STUDY DESIGN: An observational case series study design was applied to consecutive IDEA patients qualifying under the inclusion and exclusion criteria. Patient assessment of pain and disability were performed at baseline and 6 weeks, 3, 6, 12, and 24 months post-IDEA. METHODS: Selected patients underwent IDEA for an average of 15 minutes at a temperature of 90 degrees C. Analyses of outcomes included Visual Analog Scale (VAS) assessments of levels of pain, and Roland Morris Disability Questionnaire (RMDQ) assessments of functional capacity at pretreatment, and 6 weeks, 3, 6, 12, and 18 months post-treatment time points. RESULTS: At 6 months post-IDEA treatment, patients (n=51) demonstrated statistically significant improvement (P < 0.001) as measured by a mean change of over 20 points from the pretreatment score on the RMDQ. At 1 year, post data remained significant in the 33 patients who had achieved this time point. VAS pain data were also statistically significant at 6 months (P = 0.023). Analysis of patient profiles revealed that statistically significant improvement of pain and functional capacity was strongly associated with female gender and age (range of 18-45 years), and that statistically significant improvement was not sustained in males beyond the 3-6 month point. These data support the outcomes reported in the few existing observational studies to date. Of 86 patients receiving IDEA therapy, 73 provided RMDQ data at baseline and at 3 months or later and were included in the analyses. Some patients were lost to follow-up at later time points. CONCLUSIONS: These data show favorable outcomes after IDEA therapy, and suggest that women may experience more improvement than men, particularly with regard to perceived disability improvements. Data suggest that greater improvement in IDEA outcomes may be achieved by profiling the characteristics of patients who achieve the optimal long-term outcomes following treatment and should be considered during evaluation of patient eligibility for IDEA.

Adolescent↗
PubMed2004

Relative impact of covariates in prescribing warfarin according to CYP2C9 genotype.

Patients on warfarin anticoagulant therapy demonstrate wide variation in maintenance dose. Patients possessing variants (*2 and *3) of the cytochrome P450 2C9 gene require reduced maintenance doses compared to those having wild-type alleles (*1). Many other clinical factors have been shown to affect warfarin dose as well. To determine the relative impact of CYP2C9 genotype, age, gender, body surface area, concomitant medication, treatment indication and comorbidity, we conducted a retrospective cohort study in 453 patients managed by the anticoagulation service of a large, horizontally integrated, multispecialty group practice. In this largely Caucasian patient population, the CYP2C9 gene frequencies for *1/*1, *1/*2, *1/*3, *2/*2, *2/*3 and *3/*3 were 65.1%, 19.0%, 12.1%, 1.6%, 1.8% and 0.4%, respectively, approximating Hardy-Weinberg equilibrium. Mean maintenance doses for these genotypes were 36.5, 29.1, 23.5, 28.0, 18.1 and 5.5 mg/week, respectively. In univariate analyses, genotype alone accounted for 19.8% of the variability in maintenance dose. Age, body surface area and male gender accounted for 14.6%, 7.5% and 4.7%, respectively, while cardiac valve replacement as the indication for warfarin accounted for 5.4% of the variability. Collectively, these factors accounted for 33.7% of all dosing variability according to multiple regression. These results will help strengthen the mathematical models that are currently being developed for prospective gene-based warfarin dosing.

Anticoagulants↗
PubMed2004

Low-dose agrochemicals and lawn-care pesticides induce developmental toxicity in murine preimplantation embryos.

Occupational exposures to pesticides may increase parental risk of infertility and adverse pregnancy outcomes such as spontaneous abortion, preterm delivery, and congenital anomalies. Less is known about residential use of pesticides and the risks they pose to reproduction and development. In the present study we evaluate environmentally relevant, low-dose exposures to agrochemicals and lawn-care pesticides for their direct effects on mouse preimplantation embryo development, a period corresponding to the first 5-7 days after human conception. Agents tested were those commonly used in the upper midwestern United States, including six herbicides [atrazine, dicamba, metolachlor, 2,4-dichlorophenoxyacetic acid (2,4-D)], pendimethalin, and mecoprop), three insecticides (chlorpyrifos, terbufos, and permethrin), two fungicides (chlorothalonil and mancozeb), a desiccant (diquat), and a fertilizer (ammonium nitrate). Groups of 20-25 embryos were incubated 96 hr in vitro with either individual chemicals or mixtures of chemicals simulating exposures encountered by handling pesticides, inhaling drift, or ingesting contaminated groundwater. Incubating embryos with individual pesticides increased the percentage of apoptosis (cell death) for 11 of 13 chemicals (p <or= 0.05) and reduced development to blastocyst and mean cell number per embryo for 3 of 13 agents (p <or= 0.05). Mixtures simulating preemergent herbicides, postemergent herbicides, and fungicides increased the percentage of apoptosis in exposed embryos (p <or= 0.05). Mixtures simulating groundwater contaminants, insecticide formulation, and lawn-care herbicides reduced development to blastocyst and mean cell number per embryo (p <or= 0.05). Our data demonstrate that pesticide-induced injury can occur very early in development, with a variety of agents, and at concentrations assumed to be without adverse health consequences for humans.

Agriculture↗
PubMed2004

Impact of a national rural youth health and safety initiative: results from a randomized controlled trial.

OBJECTIVES: We conducted a comprehensive evaluation of a rural youth health and safety initiative implemented in 4000 National FFA (formerly Future Farmers of America) chapters across the United States. METHODS: Data were collected from high school students and their FFA advisers at 3 time intervals (preintervention, immediate postintervention, and 1 year postintervention) with a 3-group (standard, enhanced, and control), cluster-randomized, controlled trial design. RESULTS: Matched data from 3081 students and 81 advisers revealed no significant effect of this initiative on agricultural health and safety knowledge, safety attitudes, leadership, self-concept, and self-reported injuries of project participants. Data from 30 public health nurses following the intervention confirmed the program's failure to develop sustainable community partnerships. CONCLUSIONS: This nationally coordinated initiative was funded with more than $1 million donated by agribusinesses. Program implementation was inconsistent, and desired outcomes were not achieved. Future efforts should better guide effective use of private sector resources aimed at reducing agricultural disease and injury among rural youths.

Accident Prevention↗
PubMed2003

Procedural coding of spinal surgeries (CPT-4 versus ICD-9-CM) and decisions regarding standards: a multicenter study.

STUDY DESIGN: A comparison of procedural coding systems ( [ICD-9-CM] [CPT-4]) applied to lumbar spine surgery patients from six teaching institutions. OBJECTIVE: To compare the detail reflected by coding systems used to describe spinal procedures. SUMMARY OF BACKGROUND DATA: Administrative databases contain ICD-9-CM procedural codes, which are derived from hospital discharge abstracts. These databases are used, in part, to establish health care utilization patterns and set health care policy. Previous studies have demonstrated inaccuracies in ICD diagnosis coding. However, the literature is void of information regarding the accuracy of ICD procedural coding of spine procedures. METHODS: Data were complete in 143 of 150 lumbar spine surgery patients (aged 17-84 years). Surgeons assigned CPT-4 procedural codes. These codes were compared with ICD procedure codes assigned by hospital medical records staff. RESULTS: On average, in four of six hospitals, there were more CPT codes assigned to patient records by the surgeon than ICD codes assigned by hospital medical records staff. Overall, CPT codes reflected a greater level of detail than ICD codes. CONCLUSIONS: These findings illustrate the increased detail of CPT coding over ICD coding in the spinal surgery cases reviewed. The ICD procedural codes contained in administrative databases tend to underrepresent the complexity of the surgical procedures actually performed.

Adolescent↗
PubMed2003

Parental knowledge of child development and the assignment of tractor work to children.

OBJECTIVES: Many childhood farm tractor injuries occur during the performance of work that was assigned by parents, and some tractor work is beyond the developmental capabilities of children. This has been highlighted recently by a policy statement authored by the American Academy of Pediatrics. The objective of this study was 1) to assess child development knowledge of farm parents who received a new resource, the North American Guidelines for Children's Agricultural Tasks (NAGCAT), and 2) to determine whether this knowledge was associated with use of NAGCAT in the assignment of tractor jobs and with compliance with 2 aspects of the NAGCAT tractor guideline. METHODS: Secondary analysis of data collected during a randomized controlled trial that involved 450 farms in the United States and Canada was conducted. Variables assessed included 1) parental knowledge of child development across several age groups and 3 domains of child development (physical, cognitive, and psychosocial), 2) documentation of the most common tractor jobs assigned to each child, and 3) a report of whether NAGCAT was used in assigning these tractor jobs. RESULTS: High parental knowledge of child development was associated with enhanced use of NAGCAT and fewer violations when assigning tractor work to children. However, even in the presence of high knowledge, some farm parents still assigned to their children work that was in violation of NAGCAT. CONCLUSIONS: Educational interventions by themselves are not sufficient to remove many farm children from known occupational hazards. These findings are discussed in light of the recent policy statement on agricultural injuries from the American Academy of Pediatrics.

Accidents, Occupational↗
PubMed2003

Prevention of iron deficiency anemia in adolescent and adult pregnancies.

OBJECTIVE: Worldwide attention over iron deficiency anemia (IDA) in pregnancy has shifted recently from providing supplements during pregnancy to attempting to ensure that women, especially adolescents, have adequate iron stores prior to conception. We sought to determine whether adolescent and/or adult women still need supplements during pregnancy to avoid IDA, even if iron stores are adequate, and whether the IDA translates into maternal and/or infant morbidity and mortality. DESIGN: Randomized, double-blind clinical trial with placebo control. SETTING: Multicenter clinic setting in central Wisconsin. PARTICIPANTS: Adolescent women 18 years or less in their first pregnancy, and adult women 19 years or older, who were found to be healthy and iron sufficient at their first prenatal visit. METHODS: Participants were randomized to receive iron supplementation (60 mg/day elemental iron) or placebo. Serum ferritin of 12 ng/mL or less with simultaneous hemoglobin of 11 g/dL or less defined IDA. When IDA occurred at the second trimester, a therapeutic supplement of 180 mg of elemental iron per day was initiated. RESULTS: Forty-seven percent of all placebo-supplemented and 16% of all iron-supplemented patients exhibited IDA (p<0.001); 59% of adolescent placebo-supplemented and 20% of adolescent iron-supplemented patients exhibited IDA (p=0.021). Nausea, vomiting, diarrhea, and constipation were not significantly different in the iron supplemented group compared to the placebo group, and no significant differences were seen in maternal or neonatal health, but the number of women studied was limiting for analysis of these adverse events. CONCLUSION: IDA is common in healthy, iron-sufficient adolescent pregnant women during the second trimester, and body stores of iron decline in both adolescent and adult pregnancies. The incidence of IDA during adolescent and adult pregnancies is substantially reduced with 60 mg of elemental iron per day. However, there remains no clear evidence that maternal or neonatal health will benefit from correcting these deficits.

Adolescent↗
PubMed2002

Evaluation of an enhanced approach to the dissemination of the North American Guidelines for Children's Agricultural Tasks: a randomized controlled trial.

BACKGROUND: The North American Guidelines for Children's Agricultural Tasks were developed to assist farm parents in assigning developmentally appropriate and safe work to children aged 7 to 16 years. The purpose of this study was to compare the efficacy of the standard dissemination strategy with an enhanced, multiphased, dissemination approach in influencing parents to use/apply North American Guidelines for Children's Agricultural Tasks when assigning farm work to their children. METHODS: A multisite-randomized trial was performed. During 1999, 498 farms in Canada and the United States were enrolled. Enhanced dissemination activities included the provision of a video, personalized child development information, and supportive telephone calls. Follow-up with all farms occurred during the fall of 2000 to assess parental reaction to North American Guidelines for Children's Agricultural Tasks and to determine whether North American Guidelines for Children's Agricultural Tasks were actually used. RESULTS: Proportions of parents who were actively using North American Guidelines for Children's Agricultural Tasks at 15 months were 108/218 (49.5%) and 83/224 (37.1%) in the experimental and control groups, respectively (difference: 12.5%, 95% CI: 3.4, 21.7). Parental knowledge of the content of North American Guidelines for Children's Agricultural Tasks was also increased in the enhanced dissemination group. CONCLUSION: These results have important implications for dissemination of the North American Guidelines for Children's Agricultural Tasks resources. An enhanced dissemination strategy appears to increase the likelihood that North American Guidelines for Children's Agricultural Tasks will be used by farm parents.

Adolescent↗
PubMed2002

Distinguishing non-Hodgkin lymphoma from squamous cell carcinoma tumors of the head and neck by computed tomography parameters.

OBJECTIVE: Computed tomography (CT) remains the first-line imaging procedure for pre-therapeutic staging of head and neck tumors. Non-Hodgkin lymphoma (NHL) is not easily distinguished from squamous cell carcinoma (SCC), especially because NHL often appears in extranodal locations. We sought to explore whether specific CT characteristics could be used to distinguish these tumor types. METHOD: Cases of NHL and SCC involving the head and neckwere retrospectively identified. Of 165 subjects (110 NHL, 55 SCC) identified, 45 patients (19 NHL, 26 SCC) had complete CT scan records. The scans with no group identifiers were randomly presented to the radiologist for blinded review. Radiologic distribution, size, and tumor characteristics were recorded. Descriptive summaries of the data were analyzed by standard univariate statistical procedures. RESULTS: Significant differences between NHL and SCC tumors were observed: stage IV tumors (17% vs. 85%; P < .001), extranodal occurrence in the oral cavity (0% vs. 38%; P = .002), evidence of primary or extranodal tumor (11% vs. 73%; P < .001), tumor necrosis (5% vs. 54%; P <.001), non-isodensity nodes (16% vs. 50%; P = .03), and nodes in zones 5-7 (32% vs. 4%; P = .03). No significant difference was seen in the total number of nodes, the number of large nodes, or the maximum nodal diameter. CONCLUSION: While none of these features can be considered pathognomonic for either type of tumor, the distinctions may assist in distinguishing NHL from SCC of the head and neck until more sophisticated imaging techniques become widely available.

Adult↗
PubMed2002

Neck dissections: predicting postoperative drainage.

OBJECTIVES: Most head and neck dissections performed in conjunction with carcinomas of the upper aerodigestive tract require drain insertion. The time that the drains remain in place largely determines the duration of postoperative hospitalization. This study sought to retrospectively compare different neck dissections in terms of postoperative drainage and duration of hospitalization. We also sought to identify any correlation between total intraoperative blood loss and postoperative drainage. MATERIALS AND METHODS: Radical, modified radical, and selective neck dissections performed in conjunction with resection of a carcinoma of the upper aerodigestive tract over a 3-year period were evaluated. Total intraoperative blood loss at surgery, and amount and duration of postoperative drainage for each neck dissection were recorded. RESULTS: Seventy-nine neck dissections were performed on 52 patients, 27 (52%) of whom had bilateral neck dissections. Median drainage was 116.5 mL, 172 mL, and 319 mL for selective, modified radical, and radical neck dissections, respectively. Drainage differed significantly by type of neck dissection (P <.001). Drains remained in place a median of 4 days with no significant difference between different types of neck dissections. Drainage was clearly correlated with total intraoperative blood loss (Spearman correlation = 0.44, P <.001). CONCLUSION: The postoperative drainage per day was higher in radical neck dissections than modified radical neck dissections and lowest in selective neck dissections. This difference was not reflected in the duration that the drains would remain in place. Total intraoperative blood loss is a strong predictor of the amount and duration of postoperative drainage.

Adolescent↗
PubMedDate not supplied

Pregnancy outcomes for mouse preimplantation embryos exposed in vitro to the estrogenic pesticide o,p'-DDT.

Pregnancy outcomes were evaluated following uterine transfer of murine preimplantation embryos exposed in vitro to the estrogenic pesticide o,p'-dichlorodiphenyltrichloroethane (o,p'-DDT). Single-cell embryos were incubated 72 h in medium droplets containing 0.1% ethanol (control) or 0.1 microg/ml o,p'-DDT (pesticide). Morula and preblastocyst embryos were transferred in groups of eight to right uterine horns of pseudopregnant mice (n=111) and pups (n=132) were evaluated at Caesarean-section (C-section). In vitro exposure to o,p'-DDT reduced development to morula (P<0.001) and modestly increased blastomere apoptosis (P=0.05). However, treatment differences were not detected for implantation rates (35% versus 39%; P=0.64), pup numbers per dam (2.3 versus 1.9; P=0.36), transfer efficiencies (16% versus 14%; P=0.53), fetal weights (1.56 g versus 1.57 g; P=0.91), skeletal abnormalities (55% versus 66%; P=0.47), or male ratios (54.8% versus 53.8%; P=1.0). In vitro exposure of preimplantation embryos to 0.1 microg/ml o,p'-DDT for 72 h resulted in no measurable effects on subsequent implantation or pup characteristics at C-section.

Animals↗