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Biomedical subjects

S Carpenter

Publications and source records attributed to S Carpenter.

At least 181 records · Page 10Linked to original sources
PubMed1986

Weight gain in adolescent and young adult oral contraceptive users.

This study analyzed weight gain as a side effect of oral contraceptive use in teens and young adults. A retrospective chart review from 1978 to 1983 was conducted at two family planning clinics. Weight gain over 12 months was compared between females starting oral contraceptive pills and a control group using an IUD or a barrier method. One-hundred thirty-eight charts were included in the oral contraceptive group and 35 in the control group. There was no significant difference between the oral contraceptive group and control group in initial weight and weight after one year of use. Distribution of weight was also similar. There were no significant blood pressure changes. In the oral contraceptive group only five (3.7%) users listed weight gain as a side effect. The results suggest that for many young women who use oral contraceptive pills there is no greater risk of weight gain than for other sexually active young females.

Adolescent↗
PubMed1985

Hexosaminidase-A deficiency presenting as atypical juvenile-onset spinal muscular atrophy.

Three patients from two families had an unusual phenotypical variant of late-onset hexosaminidase-A deficiency. The clinical picture was dominated by spinal motor neuron involvement mimicking juvenile-onset spinal muscular atrophy. Atypical features included prominent muscle cramps, postural and action tremor, recurrent psychosis, incoordination, corticospinal and corticobulbar involvement, and dysarthria. The presence of these atypical features in patients whose lower motor neuron involvement would otherwise be consistent with juvenile-onset spinal muscular atrophy should raise the suspicion of the presence of hexosaminidase-A deficiency and GM2 gangliosidosis that can be proved by appropriate enzyme assays.

Adult↗
PubMed1985

Hypophysectomy mitigates skeletal muscle fiber damage in hamster dystrophy.

Ablation of the pituitary gland by a radiofrequency lesion markedly retarded the musculoskeletal growth of young dystrophic hamsters. The prevalence of centronucleated muscle fibers, which is a reliable cumulative index of the microscopic pathological expression of dystrophy, was drastically reduced in quadriceps muscles of 35- and 45-day-old hypophysectomized dystrophic hamsters, compared with sham-operated controls. Mitigation of skeletal muscle fiber damage by musculoskeletal growth retardation may also occur in human dystrophy.

Animals↗
PubMed1985

New observations in reducing body myopathy.

Numerous autofluorescent reducing bodies were found in deltoid and biceps muscle biopsies of a 7-year-old girl with progressive, asymmetric muscle weakness. The structures were composed of tubular filaments as seen by electronmicroscopy. They seemed to have formed around nuclei. An excess of two unidentified proteins was found in muscle homogenates. This patient, like one previously reported, had high serum titers of antibodies to coxsackievirus, but her serum, when tested by indirect immunocytochemistry, did not react with the reducing bodies.

Animals↗
PubMed1985

Hereditary sensory neuropathy: biopsy study of an autosomal dominant variety.

We studied sural nerve biopsies from a family in which three members in two generations (father, son, and daughter) had a dominantly inherited neuropathy (HSAN-I). There was marked loss of myelinated fibers, especially those of large diameter, and there was comparable loss of unmyelinated fibers. These quantitative findings differed from another reported case that provided basis for the classification of dominant and recessively inherited sensory neuropathies. Few patients have been studied, so ultrastructural and morphometric data have limited value in classification of these disorders, for which there is still no known biochemical marker.

Adolescent↗
PubMed1985

Effects of oestradiol-17 beta on peripheral plasma concentrations of LH and FSH in ovariectomized tammars (Macropus eugenii).

Two experiments, each using 8 animals, were conducted in the non-breeding and breeding seasons, respectively, and each animal was injected with 4 different doses of oestradiol benzoate over 4 trials. The resulting physiological concentrations of plasma oestradiol caused depression of both LH and FSH values. The highest dose elicited a biphasic response in LH with a pulse-like surge at 24 h after injection. There was no significant difference between the response of either hormone at the two times of the year and it is concluded that, in tammars, there is no seasonal difference in the responsiveness of the hypothalamus/pituitary to the negative feedback effect of oestradiol.

Animals↗
PubMed1985

The pathogenesis of acromegaly. Clinical and immunocytochemical analysis in 75 patients.

A series of 75 patients with acromegaly and immunocytochemically characterized pituitary adenomas has been analyzed. Tumors secreting growth hormone (GH) only were found in 21% of cases. The remainder had tumors immunoreactive for more than one pituitary hormone: GH and prolactin in 31%; GH, prolactin, and glycoprotein in 40%; and GH and glycoprotein in 8%. Microadenomas were surgically treated in 17 patients with a success rate of 82%. Overall, normalization of basal GH secretion (to less than or equal to 5 ng/ml) was achieved in 54% of cases. The implications of these findings for the pathogenesis and neurosurgical management of acromegaly are discussed.

Acromegaly↗
PubMed1984

Neurofilament subunit--related proteins in neuronal intranuclear inclusions.

Well-preserved nuclei were isolated from the brain of a patient with neuronal intranuclear inclusion disease ( NIID ). The inclusions in situ stained for proteins and, by immunohistochemical techniques, for the 200K and 68K components of the neurofilament protein triplet but were negative for the 145K neurofilament protein. At the electron microscopic level the inclusions were seen to consist of straight, randomly arranged tubular filaments 8.5 to 9.5 nm in diameter. They were resistant to extraction with hot buffer containing sodium dodecyl sulfate (SDS) and 2-mercaptoethanol, indicating that the proteins of NIID inclusions are probably cross-linked by covalent bonds other than disulfide. This feature is also exhibited by the paired helical filaments occurring in brain in Alzheimer's disease. No major differences were found in the polypeptide composition of nuclei in NIID and control nuclei resolved by SDS-polyacrylamide gel electrophoresis. The inclusions isolated from SDS-extracted nuclei were shown by immunohistochemical techniques to stain for all three neurofilament subunits, indicating that 145K -related antigenic sites were uncovered during the extraction procedure.

Aged↗
PubMed1984

Neurofibrillary axonal swellings and amyotrophic lateral sclerosis.

A series of 22 cases of amyotrophic lateral sclerosis (ALS) and 22 controls have been assessed for the presence of neurofilamentous accumulations in axons and perikarya. Large axonal swellings were seen in the spinal cord of 12 controls and of 13 ALS cases. When they were present in ALS cases they tended to be much more numerous than in controls, and when they were not present in ALS cases there tended to be severe neuronal loss in the cord. Axonal swelling on lower motor neurons appears to be a significant feature of the pathology of ALS. Its implications in terms of etiology are unknown.

Adult↗
PubMed1984

Nonsexual transmission of sexually transmitted diseases: an infrequent occurrence.

Sexually transmitted diseases occur in epidemic numbers in the United States today. Nonsexual transmission of these diseases is rarely an issue in adults. However, when the same diseases are found in children, the tendency of pediatricians and other health care practitioners has been to believe the mode of transmission is asexual. A review of gonorrhea, Chlamydia trachomatis, herpes genitalis, condyloma acuminata, Trichomonas vaginalis, syphilis, chancroid, and granuloma inguinale infections has been made to address the issue of nonsexual transmission of sexually transmitted diseases. Nonsexual transmission of these infections is an infrequent occurrence and when they affect the prepubertal child, sexual abuse must be highly suspected.

Adolescent↗
PubMed1983

Postnatal changes in canine erythrocyte pyruvate kinase isozymes.

The isozyme pattern of pyruvate kinase in canine erythrocytes changes following birth. These changes have been followed by electrophoretic, immunologic, and kinetic measurements of the isozymes. At birth, a mixture of isozymes is present consisting of the M2 isozyme and hybrid molecules containing M2 and R subunits. With increasing animal age, the content of M2 subunits decreases and the content of R subunits increases. At 6 months of age, the isozyme pattern is indistinguishable from that of adult erythrocytes which contain only the R tetramer. We conclude that there is a switch in erythrocyte pyruvate kinase gene expression during the first 6 months of postnatural life. The existence of hybrid molecules during the switch indicates that both M2 and R genes are expressed within each erythroid precursor cell. The developmental changes in erythrocyte pyruvate kinase are consistent with the role of this enzyme in the regulation of the oxygen-transport function of canine hemoglobin by 2,3-diphosphoglycerate in the postnatal period.

2,3-Diphosphoglycerate↗
PubMed1983

Reinnervation is followed by necrosis in previously denervated skeletal muscles of dystrophic hamsters.

Hind leg muscles of dystrophic hamsters were continually denervated by multiple crushes of the sciatic nerve to as long as 93 days of age. In these muscles, the prevalence of centronucleated fibers which is a cumulative index of prior necrosis, remained very low. In control dystrophic muscles the prevalence of centronucleated fibers increased steadily to approximately 80% where it leveled off. By omitting further crushes in other groups of animals, previously denervated muscles became adequately reinnervated. In the reinnervated muscles the prevalence of centronucleated fibers steadily increased throughout the necrotic phase of dystrophy at a rate that was comparable to corresponding stages of the natural history of the disease. These experiments indicated that continued denervation was effective in negating skeletal muscle fiber necrosis throughout the necrotic phase and that the electromechanical activity of muscle fibers which allows muscle fiber necrosis was not a time-locked factor.

Animals↗
PubMed1983

Metabolic and histological reversibility of thiamine deficiency.

The rapid improvement in the clinical manifestations of thiamine deficiency with thiamine supplementation is well known. To study this process in more detail, we rendered rats thiamine deficient either by dietary deprivation alone (DD) or, in addition, by daily pyrithiamine administration (DD + PT). We observed the cerebral metabolic and histological responses of these rats after 1 or 7 days of thiamine supplementation both prior to and at the onset of clinical sequelae. The cerebral metabolic response to thiamine deficiency and replenishment was determined with the [14C]deoxyglucose technique for measurement of local cerebral glucose utilization (LCGU). Our results indicate that thiamine replenishment reverses the LCGU changes resulting from thiamine deprivation of short duration. However, prolonged thiamine deprivation may result in LCGU changes that are not completely reversible by thiamine replenishment, before the appearance of the clinical or histological consequences of thiamine deficiency.

Animals↗
PubMed1983

Postnatal regulation of 2,3-DPG in sheep erythrocytes.

The erythrocyte 2,3-diphosphoglycerate (2,3-DPG) concentrations of sheep change markedly during the 1st mo following birth. From measurements of erythrocyte glycolytic enzymes and intermediate concentrations, we have identified the mechanism regulating erythrocyte 2,3-DPG in postnatal sheep. The postnatal changes in erythrocyte 2,3-DPG do not result from qualitative or quantitative changes in the intracellular activities of the Rapoport-Luebering shunt enzymes, 2,3-DPG mutase or 2,3-DPG phosphatase. The postnatal 2,3-DPG changes result from changes in the erythrocyte concentration of 1,3-DPG, which is controlled by other reactions in the glycolytic pathway. Neither changes in the glycolytic control enzymes (hexokinase, phosphofructokinase, and pyruvate kinase) nor changes in the intrinsic glycolytic rate can account for these 1,3-DPG concentration changes. 1,3-DPG concentrations are regulated by the in vivo glycolytic rate, which is controlled by the intracellular concentration of glucose, the glycolytic substrate. Glucose concentrations are 0.3 mmol/l cells in erythrocytes of fetal sheep (135-140 days gestational age), increase following birth to a peak of 3.8 mmol/l cells by the 1st wk of age, and then decline to the normal adult levels of 0.5 mmol/l cells by the end of the 1st mo.

2,3-Diphosphoglycerate↗