Biomedical subjects

J F Clapp

Publications and source records attributed to J F Clapp.

95 records · Page 6Linked to original sources

PubMedDate not supplied

Running throughout pregnancy: effect on placental villous vascular volume and cell proliferation.

Many studies have documented that placental development is altered by a variety of environmental factors which alter placental bed blood flow and/or oxygen delivery. One of these is sustained weight-bearing exercise. The purpose of this investigation was to examine the effects of running throughout pregnancy on villous vascular development and cell proliferation by testing the null hypothesis that continuing a regular running regimen throughout pregnancy has no effect on villous vascular volume or cell proliferation at term. Accordingly, placentae of 11 healthy runners with uncomplicated pregnancies were matched by placental weight, maternal diet and birth weight with those of 11 healthy controls and examined using systematic random sampling and point counting of placental tissues stained immunohistochemically with either an endothelial (CD 31, PECAM-1, endoCam) or a proliferative (Ki-67, MIB-1) marker. The placentae of the runners had greater villous vascular volumes in both absolute (77 +/- 20 cm(3) versus 47 +/- 18 cm(3), p < 0.02) and relative (% of total villous volume: 29 +/- 5% versus 20 +/- 6%, p < 0.003) terms. Likewise, they had a greater proliferation index (45 +/- 14 mitoses/1000 nuclei versus 29 +/- 10 mitoses/1000 nuclei, p < 0.008). We conclude that continuing to run regularly throughout pregnancy increases both absolute and relative villous vascular volume and cell proliferation at term. We also speculate that this exercise effect may have clinical value in cases at risk for anomalous feto-placental growth as increased villous vascular volume should improve feto-placental growth by enhancing placental transfer of oxygen and diffusible substrate.

Adult↗

PubMedDate not supplied

Nuchal cord and neurodevelopmental performance at 1 year.

OBJECTIVE: To test the null hypothesis that the presence of a nuchal cord at delivery has no effect on neurodevelopmental performance at 1 year of age. METHODS: The offspring of 190 women with clinically normal antenatal courses were evaluated within 1 month of their first birthday by a blinded observer using the Bayley Scales of Infant Development. The cases were grouped based on the presence of a symptomatic nuchal cord during labor (abnormal fetal heart rate patterns or meconium), and significant differences were detected using analysis of variance. RESULTS: A symptomatic nuchal cord was present during labor and delivery in 24% of the 190 cases. At 1 year of age scores on both Bayley scales were slightly but significantly (P < .01) lower in the offspring delivered with a symptomatic nuchal cord. The mental index was 116 +/- 9 versus 120 +/- 7, and the psychomotor index was 101 +/- 11 versus 107 +/- 9. These differences were accentuated (P = .09) when the symptomatic cases complicated by extreme tightness, multiple loops, or antenatal detection were compared to symptomatic cases without these additional complications (overall index 110 +/- 8 versus 105 +/- 10). There were no between group differences in multiple potential confounding obstetric or demographic variables. CONCLUSIONS: These data do not support the null hypothesis and suggest that symptomatic nuchal cords, which are identified before labor as being extremely tight or having multiple loops, may be associated with a subclinical deficit in neurodevelopmental performance at 1 year of age.

Adult↗

PubMedDate not supplied

The precision and accuracy of a portable heart rate monitor.

A device that would comfortably and accurately measure exercise heart rate during field performance could be valuable for athletes, fitness participants, and investigators in the field of exercise physiology. Such a device, a portable telemeterized microprocessor, was compared with direct EKG measurements in a laboratory setting under several conditions to assess its accuracy. Twenty-four subjects were studied at rest and during light-, moderate-, high-, and maximal-intensity endurance activities (walking, running, aerobic dancing, and Nordic Track simulated cross-country skiing. Differences between values obtained by the two measuring devices were not statistically significant, with correlation coefficient (r) values ranging from 0.998 to 0.999. The two methods proved equally reliable for measuring heart rate in a host of varied aerobic activities at varying intensities.

Adult↗

PubMedDate not supplied

Second-trimester placental volumes predict birth weight at term.

OBJECTIVE: To test the hypothesis that second-trimester placental growth is a major determinant of size at birth in healthy, active women. METHODS: Three serial measurements of fetal morphometry and placental volume were obtained between the 14th and 26th weeks of an accurately dated singleton pregnancy in 40 subjects. RESULTS: Second-trimester placental volumes were variable, increasing from (mean +/- standard deviation) 130 +/- 35 to 248 +/- 67 and to 375 +/- 92 cm3 at 16, 20, and 24 weeks, with an average growth rate of 31 +/- 8 cm3/weeks. At delivery, fresh placental volumes and birth weights were also variable, ranging between 304-823 cm3 and 2.6-4.4 kg, respectively. Significant correlations (r > 0.79) were present between second-trimester placental volume or growth rate and placental volume at delivery and birth weight, corrected for gestational age and infant sex. However, correlations between second-trimester fetal biometry and both corrected birth weight and birth weight percentile were poor (r < 0.45). CONCLUSION: Second-trimester placental volumes and growth rates are good predictors of size at birth in healthy, active women. We speculate that this technique may have real value as an early screening tool to identify cases at risk of anomalous third-trimester growth.

Adult↗

PubMedDate not supplied

Cord blood leptin reflects fetal fat mass.

OBJECTIVE: To explore the relationship between leptin levels and fat mass at the time of birth to test the hypothesis that the level of leptin in the fetal circulation is primarily an index of fetal fat mass. METHODS: Leptin concentration was measured in cord blood obtained from the offspring of 42 women. Trimmed, drained placental weight and neonatal morphometrics were obtained after delivery. RESULTS: The ranges in maternal weight (46.7-93.2 kg), weight gain (3.2-22.6 kg), percent body fat (10-34%), placental weight (290-688 g), birth weight (2.63-4.32 kg), neonatal fat mass (179-782 g), and cord blood leptin (1.7-26.7 ng/mL) were wide. The only morphometric variable that explained a significant portion of the variation in cord blood leptin levels was neonatal fat mass (r2 = 0.41), and this relationship was not significantly improved by best subset regression of additional fetal and placental morphometric variables (r2 = 0.46). CONCLUSION: These data support the hypothesis and suggest that in the fetus, as in the child and the adult, fat mass is the major determinant of circulating leptin levels.

Adipose Tissue↗