Biomedical subjects

F C Bennett

Publications and source records attributed to F C Bennett.

At least 19 recordsLinked to original sources

PubMed1992

Melittin-induced changes in lipid multilayers. A solid-state NMR study.

Solid-state 1H, 13C, 14N, and 31P NMR spectroscopy was used to study the effects of the bee venom peptide, melittin, on aligned multilayers of dimyristoyl-, dilauryl- and ditetradecyl-phosphatidylcholines above the gel to liquid-crystalline transition temperature, Tc. Both 31P spectra from the lipid headgroups and 1H resonances from the lipid acyl chain methylene groups indicate that the peptide does not affect the mosaic spread of the lipid molecules at lipid:peptide molar ratios of 10:1, or higher. None of the samples prepared above Tc showed any evidence of the formation of hexagonal or isotropic phases. Melittin-induced changes in the chemical shift anisotropy of the headgroup phosphate and the lipid carbonyl groups, and in the choline 14N quadrupole splittings, show that the peptide has effects on the headgroup order and on the molecular organization in the sections of the acyl chains nearest to the bilayer surface. The spin-lattice relaxation time for the lipid acyl chain methylene protons was found to increase and the rotating-frame longitudinal relaxation time to markedly decrease with the addition of melittin, suggesting that motions on the nanosecond time scale are restricted, whereas the slower, collective motions are enhanced in the presence of the peptide.

Amino Acid Sequence↗

PubMed1992

Identification of neurodevelopmental abnormality at four and eight months by the movement assessment of infants.

The predictive validity of infant neuromotor evaluation by the Movement Assessment of Infants (MAI) was investigated in low-birthweight infants. Motor performance at four and eight months was examined in relation to neurodevelopmental outcome at 18 months of age. Correlations were equally strong between total MAI risk scores at four and eight months and performance on the Bayley Scales. Muscle tone observations were more discriminating at four months, and automatic reactions and volitional movement were most predictive at eight months. The MAI was highly sensitive to neurodevelopmental abnormality at four and eight months and more sensitive than the Bayley Motor Scale; both assessment tools had lower specificity at eight months. The high false-positive rate is attributed to transient neuromotor abnormalities and immaturity of motor function in low-birthweight infants with normal outcome.

Brain Damage, Chronic↗

PubMed1992

Effects of ethanol and its fluorinated analogues on the calcium ATPase of sarcoplasmic reticulum.

The effects of ethanol, monofluoro- and trifluoroethanol on the hydrolysis of ATP and coupled Ca2+ translocation by sarcoplasmic reticulum Ca(2+)-ATPase (EC 3.6.1.38) were measured. All three alcohols had parallel effects on the enzyme activities at concentrations up to 200 mM, suggesting a similar mechanism of action. 19F nuclear magnetic resonance spectroscopy was used to investigate their site of action in the purified enzyme.

Animals↗

PubMed1991

Effectiveness of developmental intervention in the first five years of life.

Developmental intervention in the first 5 years of life is an expanding, complex enterprise. Documenting efficacy by traditional scientific methods has proven to be elusive for a number of practical reasons, e.g., target population heterogeneity, methodology variability, inadequate outcome measures, and cost of longitudinal cohort designs. Nevertheless, despite these shortcomings, there is accumulating research information as to which types of intervention approaches are likely to be most beneficial to specific groups of infants and children and their families. It is quite clear that preventive strategies for at-risk children and families are different than ameliorative strategies for children with established disabilities. It is also clear that comprehensive evaluation of effectiveness must include consideration of both functional child gains (e.g., social, communication, mobility, and adaptive skills) and enhancement of family function. It is the pediatrician's responsibility to be adequately informed about contemporary developmental interventions in order to balance parental hopes and needs with potential benefits.

Child, Preschool↗

PubMed1991

Predictors of neurodevelopmental outcome following bronchopulmonary dysplasia.

In infants with bronchopulmonary dysplasia, the influence of the severity of their pulmonary disease on neurodevelopmental outcome is unknown. Neurodevelopmental outcomes at a mean age of 36 months were assessed in 27 premature subjects who had bronchopulmonary dysplasia. Subjects had a mean birth weight of 940 g (range, 540 to 1690 g) and a mean gestational age of 27 weeks (range, 25 to 31 weeks). The duration of mechanical ventilation ranged from 22 to 128 days, and the duration of requirement of supplemental oxygen ranged from 34 to 1033 days. No significant correlations were found between duration of mechanical ventilation or oxygen therapy and overall neurodevelopmental outcome. In contrast, cranial ultrasound findings of intracranial hemorrhage and/or periventricular echodensity related specifically to poorer cognitive outcome. By age 3 years, severity of bronchopulmonary dysplasia is not a sufficient predictor of neurodevelopmental outcome. Intracranial hemorrhage and periventricular echodensity continue to be important predictors.

Bronchopulmonary Dysplasia↗

PubMed1990

Effects of electronic fetal-heart-rate monitoring, as compared with periodic auscultation, on the neurologic development of premature infants.

In a multicenter, randomized clinical trial, we assessed the early neurologic development of 93 children born prematurely whose heart rates were monitored electronically during delivery and compared it with that of 96 children born prematurely whose heart rates were periodically monitored by auscultation. All the children were singletons with cephalic presentation, and all weighed less than or equal to 1750 g at birth. The mental and psychomotor indexes of the Bayley Scales of Infant Development (standardized mean score +/- SD, 100 +/- 16) and a formal neurologic examination were administered at three follow-up visits (at 4, 8, and 18 months of age, corrected for gestational age). At 18 months, the mean mental-development scores in the groups receiving electronic fetal monitoring and periodic auscultation were 100.5 +/- 2.4 and 104.9 +/- 1.8, respectively (P greater than 0.1). The mean psychomotor-development scores in the two groups at 18 months were 94.0 +/- 2.4 and 98.3 +/- 1.8, respectively (P greater than 0.1). The incidence of cerebral palsy was higher in the electronically monitored group--20 percent as compared with 8 percent in the group that was monitored by auscultation (P less than 0.03). In the electronic-fetal-monitoring group (but not in the periodic-auscultation group), the risk of cerebral palsy increased with the duration of abnormal fetal-heart-rate patterns, as assessed by retrospective review (chi 2 trend = 12.71, P less than 0.001). The median time to delivery after the diagnosis of abnormal fetal-heart-rate patterns was 104 minutes with electronic fetal monitoring, as compared with 60 minutes with periodic auscultation. We conclude that as compared with a structured program of periodic auscultation, electronic fetal monitoring does not result in improved neurologic development in children born prematurely.

Birth Weight↗

PubMed1990

Diet and female sex hormone concentrations: an intervention study for the type of fat consumed.

A possible mechanism by which dietary fat may influence the development of breast cancer is by influencing the concentration of female sex hormones. This study investigated the effect of alteration in the type of fat consumed on concentrations of female sex hormones in serum. Female volunteers were randomly assigned to continue on their usual meat-eating diet, change to a vegetarian diet, or change to a diet that was predominantly vegetarian but where fish was consumed at least three times per week. Change to the vegetarian or fish diet had little effect on diet total hormone concentrations; however, the amount of estradiol was significantly decreased in the vegetarian group. When nutrient consumption was correlated with hormone concentrations, prolactin was directly associate with fat consumption, sex-hormone-binding globulin was inversely associated with fat consumption (particularly cholesterol consumption), and the proportion of nonprotein-bound estradiol was directly associated with complex carbohydrate consumption.

Adult↗

PubMed1990

Birth weight less than 800 grams: changing outcomes and influences of gender and gestation number.

Mortality and neurodevelopmental morbidity were compared in two cohorts of neonates with birth weights of less than 800 g. The neonates, born in the years 1977 through 1980 (original cohort) and 1983 through 1985 (current cohort), were patients in the same university intensive care nursery. Mortality was 80% in the original cohort and 64% in the current cohort (P = .01). In the current cohort, survival was significantly better for neonates with birth weights of more than 749 g (58% vs 27%; P = .001). Survival was also significantly associated with gender and with gestation number (female survival was 48% and male survival was 23%, P = .003; singleton survival was 41% and twin survival was 21%, P = .03). Prevalence of major central nervous system handicaps did not significantly differ between the two study groups, but severity of handicap was worse for the current study group. Morbidity in the current cohort was most severe for twins (67% with a major central nervous system handicap) and was least severe for singleton girls (4% with a major central nervous system handicap, P = .002). Delivery mode appeared to affect outcome. Although there were more nursery admissions and more survivors among neonates with birth weights of less than 800 g during the period 1983 through 1985 compared with the period 1977 through 1980, overall neurodevelopmental morbidity worsened.

Birth Weight↗

PubMed1990

Periventricular echodensities detected by cranial ultrasonography: usefulness in predicting neurodevelopmental outcome in low-birth-weight, preterm infants.

Forty-eight low-birth-weight, preterm graduates of the University of Washington's neonatal intensive care unit who had received periodic, serial scanning by means of cranial ultrasonography during the first 4 to 6 weeks of life were longitudinally observed in an interdisciplinary neurodevelopmental follow-up program to a mean corrected age of 18 months. Mean birth weight for the sample was 1286 g; mean gestational age was 29 weeks. Periventricular echodensities were graded from 0 to 3, with 0 indicating no densities and 3 indicating cystic formation. Intracranial hemorrhage was graded in the conventional manner from 0 to IV. Neurodevelopmental outcome was assessed by means of a neurologic examination and the Bayley Scales of Infant Development. To synthesize the results, neurodevelopmental outcome for each subject was classified as normal, demonstrating minor abnormalities, or demonstrating major abnormalities. Multiple statistical analyses with various subgroupings of subjects consistently indicated severe intracranial hemorrhage (grades III and/or IV) to be a better predictor of overall neurodevelopmental outcome than grade of periventricular echodensity, including small cysts. These results suggest a wide range of outcomes after detection of periventricular echodensities and caution against communicating overly pessimistic prognoses in many cases.

Cerebral Hemorrhage↗

PubMed1989

Vitamin therapy and children with Down syndrome: a review of research.

The claim that large doses of vitamin-mineral supplements benefit mentally retarded children has captured the attention of the general public and the medical profession. A study by Harrell, Capp, Davis, Pearless, and Ravitz (1981) reported increases in IQ and improvements in behavior among mentally retarded subjects (one third of whom were children with Down syndrome) receiving nutritional supplementation. However, subsequent studies, focusing exclusively on children with Down syndrome and using less flawed research designs, have demonstrated that vitamin therapy is not useful for members of this population.

Child↗

PubMed1988

Pediatricians' perceptions of the effectiveness of early invention for at-risk and handicapped children.

To evaluate pediatricians' perceptions of the effectiveness of early intervention for handicapped and at-risk children, all board-certified pediatricians in the state of Ohio were surveyed. A detailed questionnaire was developed which included the use of brief but specific cases identifying eight different children with documented handicaps and two cases of children at developmental risk. Overall, the results indicated that pediatricians judged early intervention to produce at least a modest effect on children's general development and function. A more optimistic perspective was held for families in that involvement in early intervention was viewed as improving substantially the ability of families to cope with the problems of a handicapped or at-risk child and to provide a supportive and stimulating environment. However, perceptions of effectiveness did vary for specific disability and at-risk groups. The correspondence between perceived effectiveness and existing research findings also was discussed.

Adaptation, Psychological↗

PubMed1988

Preschool motor skills of children born prematurely and not diagnosed as having cerebral palsy.

To evaluate the preschool motor skills of children born prematurely, we examined 90 children who were participating in a longitudinal follow-up program at 4 1/2 years corrected age. Children with major neurological impairments, such as cerebral palsy, were excluded from this investigation. Study subjects' gestational ages ranged from 24 to 36 weeks. Both gross and fine motor function were assessed with standardized instruments. Overall, the later motor development of these children was reassuringly intact and within the average range on all measures. Nevertheless, extremely low birth weight (less than 1000 g) children as a group displayed significantly inferior skills in all motor functions. Symptomatic intracranial hemorrhage was also associated with significantly poorer motor performance.

Cerebral Palsy↗

PubMed1987

Status of infants at birth and risk for adverse neonatal events and long-term sequelae: a study in low birth weight infants.

We evaluated the relationship of infant status at birth to neonatal morbidity and long-term development in 246 low birth weight infants (600 to 1750 gm). Nineteen percent of infants had 1-minute Apgar scores of less than or equal to 3, and 8% had an umbilical artery pH of less than or equal to 7.2. Acidosis was associated with an increased risk of grade 3 to 4 intracranial hemorrhage (odds ratio = 3.3). Low 1-minute Apgar score was associated with an increased risk of death (odds ratio = 4.8). Grade 3 to 4 intracranial hemorrhage was a strong risk factor for cerebral palsy among survivors (odds ratio = 16.1), as was low 1-minute Apgar score (odds ratio = 2.9). Only 15% of cases of cerebral palsy in this study were associated with acidosis at birth.

Acidosis↗

PubMed1987

Use of physical and neurologic observations in assessment of gestational age in low birth weight infants.

The relative validities of three clinical assessment methods for estimating gestational age in newborn low birth weight infants were evaluated with reference to estimates based on the date of the mother's last menstrual period. For 1246 infants in eight diverse institutions, estimates based on physical criteria correlated more strongly with dates estimates, yielded estimates more similar on average to dates estimates, and yielded higher proportions of correct classifications of prematurity and small for gestational age than did estimates based on neurologic criteria or neurologic and physical criteria combined. These results support the use of physical criteria rather than neurologic or combined criteria for the clinical assessment of gestational age in low birth weight infants. In a subsample of 511 black and white infants, there were no ethnic differences in mean error of estimate for any of the three methods.

Analysis of Variance↗

PubMed1987

The relationship between the Bayley Scales of Infant Development and preschool gross motor and cognitive performance.

Early identification of disabilities enables early intervention by occupational therapists and other health professionals. Because the number of children who can be seen in therapy is limited, it is important to be able to identify those infants most likely to have deficits at a later age. Therefore, it is necessary to study and understand the relationship between infants' scores on early developmental assessments and later developmental outcomes. The purpose of this study was to determine the extent to which scores on the Bayley Scales of Infant Development (BSID) during the first 2 years of life are related to motor and cognitive performance at 4 1/2 years for a sample of children identified at birth as biologically high risk. This retrospective study involved 70 children who were evaluated at corrected ages of 4 months, 1 year, 2 years, and 4 1/2 years. The 4-month BSID Mental and Motor Scale scores did not relate significantly to later cognitive motor performance. In contrast, the 12-month BSID Mental Scale scores related significantly to preschool scores on both the motor and cognitive measures. However, the 24-month BSID Mental Scale scores related significantly only to scores on the preschool cognitive measures. Though significant, these correlation coefficients had small magnitudes. Thus, therapists should be cautious about using BSID testing at 4 months, 1 year, and 2 years when attempting to predict later preschool performance.

Child Development↗

PubMed1987

Training residents in developmental pediatrics: results from a national replication.

This investigation examined the extent to which a structured curriculum in developmental pediatrics could be applied effectively to a wide range of pediatric residency training programs. Residents drawn principally from sites not involved in the original development of a curriculum in developmental pediatrics were assigned randomly to prerotation control or postrotation experimental groups. Based on an objective case management test, residents who had participated in the rotation defined by the curriculum scored significantly higher than those who had not. Differences between experimental and control groups were similar for both the first and second evaluation years and for residents drawn from the original and new sites (total n = 161). Subjective evaluations by residents and faculty preceptors confirmed the utility of curriculum.

Clinical Competence↗

PubMed1987

The high risk infant: transitions in health, development, and family during the first years of life.

Greater numbers of preterm, low birth weight ("high risk") infants are surviving than ever before. It has become increasingly important for physicians and other health care professionals to become familiar with the many real and potential problems seen in this population of children during the first years of life and beyond. The residue of illnesses that are presented in the neonatal intensive care nursery and major health vulnerabilities of the early years are discussed in this article. Normal variations in neurodevelopmental patterns unique to preterm infants and neurodevelopmental disabilities which have a higher prevalence in this population are presented. The impact of a high risk infant on the family unit is described. Finally, resources and interventions available to the child, family, and health care provider during and following the transition from the hospital to home are reviewed.

Child↗

PubMed1987

Effect of low-fat diet on female sex hormone levels.

The hypothesis that dietary fat acts as a promotional agent for the development of breast cancer by influencing sex hormone levels was tested in a dietary intervention study. Thirty-three women in good health were randomly allocated to commence either a standard diet (deriving 40% of their energy from fat) or a low-fat diet (deriving 20% of their energy from fat). After 2 months, the women were crossed over to the alternative diet for another 2 months. Serum hormone and lipid levels were measured in the middle and at the end of each dietary period. In premenopausal women, the low-fat diet appeared to decrease levels of both non-protein-bound estradiol (1.48 down to 1.27%; P = .07) and non-protein-bound testosterone (1.06 down to 0.86%; P = .11). Cholesterol levels were lowered by the low-fat diet and were significantly associated with estradiol, testosterone, and dehydroepiandrosterone. High-density lipoprotein (HDL) cholesterol was associated with estradiol and prolactin. For the postmenopausal women, the low-fat diet lowered cholesterol and HDL cholesterol levels, but there were not the same associations with the hormones. These findings add weight to the concept that attention to diet may be a means of reducing the incidence of breast cancer in our community.

Adult↗