A Prospective Study of the Association Between Vigorous Physical Activity During Pregnancy and Length of Gestation and Birthweight

Current US pregnancy-related physical activity recommendations do not provide specific guidance for vigorous intensity activity. We examined the associations between vigorous physical activity during pregnancy and length of gestation and birthweight. Methods: Women were recruited before 10?weeks gestation. At 13?C16?weeks gestation, participants reported the type, frequency, and duration of their typical weekly vigorous physical activities. Activity domains included recreational, occupational, household, and child/adult care. Infant birth date was obtained from medical or vital records; if unavailable, self-report was used. Birthweight (from vital records) was studied among term births. We analyzed gestational age among 1,647 births using discrete-time survival analysis. We used logistic and linear regression to analyze preterm birth (birth at <37?weeks) and birthweight, respectively. Vigorous recreational activity was associated with longer gestation (any vs. none, hazard ratio (HR) [95% CI]: 0.85 [0.70, 1.05]) and we did not detect any dose?Cresponse association. Higher frequency of vigorous recreational activity sessions (adjusted for total volume of activity) was associated with a decreased odds of preterm birth (??4 sessions/week vs. 0 or 1, OR [95% CI]: 0.08 (0.006, 1.0). Birthweight was not associated with physical activity measures. In summary, vigorous physical activity does not appear to be detrimental to the timing of birth or birthweight. Our data support a reduced risk of preterm birth with vigorous recreational activity, particularly with increased frequency of recreational activity sessions. Future studies should investigate the components of physical activity (i.e., intensity, duration, and frequency) in relation to birth outcomes.     

State Disparities in Time Trends of Adolescent Body Mass Index Percentile and Weight-Related Behaviors in the United States

Evidence is conflicting as to whether youth obesity prevalence has reached a plateau in the United States overall. Trends vary by state, and experts recommend exploring whether trends in weight-related behaviors are associated with changes in weight status trends. Thus, our objective was to estimate between-state variation in time trends of adolescent body mass index (BMI) percentile and weight-related behaviors from 2001 to 2007. A time series design combined cross-sectional Youth Risk Behavior Survey data from 272,044 adolescents in 29 states from 2001 to 2007. Self-reported height, weight, sports participation, physical education, television viewing, and daily consumption of 100% fruit juice, milk, and fruits and vegetables were collected. Linear mixed models estimated state variance in time trends of behaviors and BMI percentile. Across states, BMI percentile trends were consistent despite differences in behavioral trends. Boys experienced a modest linear increase in BMI percentile (ß = 0.18, 95% CI: 0.07, 0.30); girls experienced a non-linear increase, as the rate of increase declined over time from 1.02 units in 2001–2002 (95% CI: 0.68, 1.36) to 0.23 units in 2006–2007 (95% CI: ?0.09, 0.56). States in which BMI percentile decreased experienced a greater decrease in TV viewing than states where BMI percentile increased. Otherwise, states with disparate BMI percentile trends did not differ with respect to behaviors. Future research should explore the role of other behaviors (e.g., soda consumption), measurement units (e.g., portion size), and societal trends (e.g., urban sprawl) on state and national adiposity trends.     

A method for simultaneous study of the karyotype, morphology, and immunologic phenotype of mitotic cells in hematologic malignancies

A major problem in the cytogenetic analysis of hematologic neoplasms has been an inability to identify the cell from which the chromosomes were obtained. We describe a procedure that allows simultaneous analysis of karyotype and cell cytology in mitotic cells. The method differs from conventional cytogenetic analysis in that after mild hypotonic treatment, the cells are cytocentrifuged onto glass slides. In mitotic cells, this procedure often results in adequate spread of the chromosomes within the intact cell membrane. The cytoplasmic structure also remains intact, so that cytologic preparations are of good quality. Morphologic and immunologic identification of mitotic cells can be done using routine hematologic stains, such as Giemsa or Sudan black B, and various antisera using immunofluorescence techniques. The chromosomes can be simultaneously analyzed either without banding on slides stained with Giemsa or with Q-banding on slides stained with immunofluorescence techniques. Identification of numerical and structural karyotype aberrations thus is possible in morphologically identified cells.     

Acute renal rejection versus acute tubular necrosis in a canine model: MR evaluation

Findings of magnetic resonance (MR) imaging in acute renal rejection and acute tubular necrosis (ATN) were studied in dogs. On T1-weighted images, corticomedullary differentiation was absent in kidneys undergoing acute rejection. The loss of corticomedullary differentiation in these kidneys was secondary to a decrease in the relative signal intensity of the cortex, indicating prolongation of the T1 relaxation time of the cortex. In contrast, corticomedullary differentiation was preserved on T1-weighted images of autotransplanted kidneys and kidneys with ATN. MR imaging findings correlated with changes in water content in these three groups of kidneys. Kidneys undergoing acute rejection showed a marked increase in water content compared with kidneys in the other two groups. No change in fat content was found in any group.     

A generational study of glyphosate-tolerant soybeans on mouse fetal, postnatal, pubertal and adult testicular development.

The health safety of transgenic soybeans (glyphosate-tolerant or Roundup Ready) was studied using the mammalian testis (mouse model) as a sensitive biomonitor of potential toxic effects. Pregnant mice were fed a transgenic soybean or a non-transgenic (conventional) diet through gestation and lactation. After weaning, the young male mice were maintained on the respective diets. At 8, 16, 26, 32, 63 and 87 days after birth, three male mice and an adult reference mouse were killed, the testes surgically removed, and the cell populations measured by flow cytometry. Multi-generational studies were conducted in the same manner. The results showed that the transgenic foodstuffs had no effect on macromolecular synthesis or cell growth and differentiation as evidenced by no differences in the percentages of testicular cell populations (haploid, diploid, and tetraploid) between the transgenic soybean-fed mice and those fed the conventional diet. Additionally, there were no differences in litter sizes and body weights of the two groups. It was concluded that the transgenic soybean diet had no negative effect on fetal, postnatal, pubertal or adult testicular development.