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Biomedical subjects

J A Schlechte

Publications and source records attributed to J A Schlechte.

At least 19 recordsLinked to original sources
PubMed2000

The relationship between the density of the alveolar processes and that of post-cranial bone.

Skeletal mass declines in all populations with age, and the literature suggests that changes in oral bone may be linked to the status of the post-cranial (systemic) skeleton. However, there is a lack of information defining the relationship between alveolar process bone and the post-cranial skeleton in healthy individuals. The purpose of this study was to determine: (1) if the bone densities of the maxillary and mandibular alveolar processes are related to the bone density of the spine, hip, or radius in healthy women; and (2) if the alveolar process densities decline with age. Forty-one dentate Caucasian women aged 20 to 78 years underwent assessment of post-cranial (systemic) and alveolar process bone. D-speed vertical bitewing and periapical radiographs incorporating aluminum stepwedges, controlled exposure and processing conditions, and a density correction algorithm were used to make alveolar process density assessments with regions of interest (ROIs) apical to crestal bone and intrabony defects. Anteroposterior lumbar (L1 to L4) and lateral lumbar (L2 to L4) spine, total hip (and subregions), and radius bone densities were determined by dual-energy x-ray absorptiometry (DEXA). Correlation analysis revealed significant relationships between maxillary alveolar process bone density and the density of the mandibular alveolar process (r = 0.57, p < or = 0.001), anteroposterior lumbar spine (r = 0.53, p < or = 0.001), lateral lumbar spine (r = 0.52, p < or = 0.001), total hip (r = 0.39, p = 0.01), total radius (r = 0.39, p = 0.01), and age (r = -0.38, p = 0.01). A two-tailed t test comparison revealed significantly greater maxillary alveolar process bone density in women younger than 50 years of age than in those 50 and older (p < or = 0.01). We conclude that the density of maxillary alveolar process bone is significantly related to the density of the mandibular alveolar process, lumbar spine, hip, and radius in healthy women and that maxillary alveolar process bone density declines with age.

Absorptiometry, Photon↗
PubMed1998

Effects of prolactin in stimulating disease activity in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE), a chronic autoimmune illness, is influenced by hormones. High prolactin concentrations were associated with early death from autoimmune renal disease in NZB/NZW mice, an animal model of severe SLE. NZB/NZW mice that delivered and nursed pups and those that underwent pseudopregnancy had changes in serum IgG and autoantibodies. NZB/NZW mice treated with the prolactin-suppressing drug bromocriptine had prolonged lives. Elevated serum prolactin concentrations are reported in SLE patients of both sexes. We found four women with long-standing hyper-prolactinemia who developed SLE. A survey of premenopausal women whose sera were submitted for autoantibody testing showed that 20% with anti-ds-DNA antibodies also had high prolactin levels. Many hyperprolactinemic patients whose sera were referred to an endocrinology laboratory had positive FANA tests (women 33%, men 53%) but did not have SLE. Disease activity was suppressed in six of seven SLE patients treated with bromocriptine. All had elevated disease activity and five became unexpectedly hyperprolactinemic after treatment stopped. Manipulating serum prolactin affords a means of treating clinical SLE activity.

Bromocriptine↗
PubMed1997

Prolactinoma.

Explore the source record for details and available documents.

Dopamine Agonists↗
PubMed1995

Clinical impact of hyperprolactinaemia.

Prolactinomas are benign, functioning pituitary tumours that cause reproductive dysfunction in men and women. PRL-secreting microadenomas have a benign clinical course and may even disappear without treatment. Absolute indications for treatment of hyperprolactinaemia include the need to restore fertility and the presence of a macroadenoma. A dopamine agonist is the treatment of choice regardless of tumour size and will normalize PRL and restore menses in the majority of cases. Hypogonadism induced by hyperprolactinaemia is associated with decreased spinal bone mineral content, but it is not clear whether the bone loss is progressive. Bone mass improves after treatment of the hyperprolactinaemia but does not normalize. The safety of chronic oestrogen therapy in women with hyperprolactinaemic amenorrhoea who are not desirous of fertility remains to be elucidated by ongoing clinical trials.

Bone Diseases, Metabolic↗
PubMed1994

Sequential MR enhancement pattern in normal pituitary gland and in pituitary adenoma.

PURPOSE: To measure and evaluate the temporal enhancement characteristics of the normal pituitary gland and pituitary adenoma. METHODS: Thirty healthy subjects and 10 patients with sellar pituitary adenomas were studied prospectively using dynamic MR imaging with a 5- or 10-sec temporal resolution during a bolus injection of gadolinium. RESULTS: Qualitative visual analysis demonstrated a consistent sequential pattern of pituitary enhancement in which the posterior lobe enhanced earlier than the anterior lobe by approximately 35 sec. Quantitative analysis revealed that posterior lobe enhancement occurred 9.8 +/- 1.5 sec (mean +/- SEM) before the anterior lobe in healthy subjects, whereas tumor enhancement occurred significantly before the anterior lobe but only slightly before the posterior lobe in patients with adenomas. CONCLUSION: The sequential enhancement pattern of the normal pituitary gland was found to be consistent with its vascular anatomy. In contrast to previous reports, pituitary adenomas were found to enhance earlier than the anterior lobe. These results suggest that pituitary adenomas have a direct arterial blood supply, similar to that of the posterior pituitary lobe.

Adenoma↗
PubMed1993

Neurologic complications of thyroid and parathyroid disease.

Common thyroid and parathyroid disorders present with reversible neurologic signs and symptoms affecting the central and peripheral nervous system, musculature, and mental function. Patients with thyrotoxicosis may have myopathy, spasticity, seizures, and multiple psychiatric symptoms. A deficiency of thyroid hormone also causes muscle weakness and may be accompanied by reversible muscle hypertrophy or movement disorders. The chronic hypercalcemia that develops secondary to hyperparathyroidism produces many psychiatric and cognitive symptoms, as well as a reversible myopathy. Calcium deficiency leads to neuromuscular irritability, paresthesias, and tetany. Psychiatric disorders are also common in this disorder.

Diagnosis, Differential↗
PubMed1992

Intracranial dissemination of an ACTH secreting pituitary neoplasm--a case report and review of the literature.

A 52-year-old woman developed recurrent hypercortisolism 3 yr after successful surgical treatment of Cushing's disease. At postmortem, eosinophilic pituitary tissue showing positive ACTH immunohistochemical staining was present in the frontal lobe and cerebellum but there was no tumor in the sella. In the absence of a pituitary tumor, extrasellar ACTH producing tissue could arise from seeding of the cerebrospinal fluid with tumor cells at the time of operation or from an atypical pituitary carcinoma. In this report we review the mechanisms of intracranial dissemination of pituitary tissue and ACTH-secreting pituitary carcinomas, including parasellar invasion, meningeal seeding, and cerebrospinal and hematogenous spread.

Adenoma↗
PubMed1991

Prospective study of postpartum blues. Biologic and psychosocial factors.

Potential biologic and psychosocial causative factors for the postpartum blues were tested in a prospective study of 182 women followed up from the second trimester of pregnancy until postpartum week 9. Personal and family history of depression, depressive symptoms, stressful life events, and social adjustment were all assessed during the second trimester. Levels of progesterone, prolactin, estradiol, free and total estriol, and free and total cortisol were measured on several occasions during late pregnancy and early puerperium. Obstetric and child-care stressors and the postpartum blues were assessed after delivery. Predictors of the postpartum blues were personal and family history of depression, social adjustment, stressful life events, and levels of free and total estriol. Our results support the hypothesis that the postpartum blues is within the spectrum of affective disorders.

Adult↗
PubMed1991

Effects of chronic marijuana use on testosterone, luteinizing hormone, follicle stimulating hormone, prolactin and cortisol in men and women.

To investigate possible effects of chronic marijuana use on reproductive and stress hormones, we assayed testosterone, luteinizing hormone, follicle stimulating hormone, prolactin, and cortisol in 93 men and 56 women with a mean (+/- S.E.) age of 23.5 +/- 0.4 years. Hormone values were compared among groups of subjects stratified according to frequency of marijuana use (frequent, moderate and infrequent; N = 27, 18, and 30, respectively) and non-using controls (N = 74). Chronic marijuana use showed no significant effect on hormone concentrations in either men or women.

Adolescent↗
PubMed1991

Controlled prospective study of postpartum mood disorders: psychological, environmental, and hormonal variables.

Demographic, psychiatric, social, cognitive, and life stress variables were used to determine the etiology of depression in childbearing (CB; n = 182) and nonchildbearing (NCB; n = 179) women. Hormonal variables in postpartum depression were also evaluated. In the CB group predictors of depression diagnosis were previous depression, depression during pregnancy, and a Vulnerability (V) x Life Stress (LS) interaction; predictors of depressive symptomatology were previous depression, depressive symptoms during pregnancy, life events, and V x LS. Only estradiol was associated with postpartum depression diagnosis. In the NCB group V X LS was the only predictor of depression diagnosis; depressive symptoms during pregnancy and life events were predictors of depressive symptomatology. Previous findings about depression vulnerability were replicated. The significant V x LS interactions support the vulnerability-stress model of postpartum depression.

Adult↗
PubMed1990

Potentiation of glucocorticoid-induced cytolysis in sensitive human leukemic cells by an inhibitor of ADP-ribosylation.

3-Aminobenzamide, a general inhibitor of poly(ADP-ribose)polymerase, potentiated the triamcinolone acetonide-mediated growth inhibition and lysis of the glucocorticoid-sensitive CEM-C7 human leukemic cell line. This potentiation was dose-dependent with maximal response being detected at 3 mM 3-aminobenzamide, and was completely blocked by the glucocorticoid receptor antagonist RU 38486. Scatchard analysis of whole cell specific [3H]triamcinolone acetonide binding data did not reveal any effect of 3-aminobenzamide on either the number of intracellular receptor binding sites or their affinity for the agonist. Treatment of the ICR-27 cell line, which is a glucocorticoid resistant mutant isolated from CEM-C7, with 3-aminobenzamide did not restore triamcinolone acetonide sensitivity. Similarly, 3-aminobenzamide treatment of several other lymphoid cell lines (human HL60 and IM-9 and murine L1210 cells) which contain functional receptors but are not normally lysed by glucocorticoid agonists, failed to induce sensitivity to triamcinolone acetonide. Since treatment of sensitive lymphoid cells with glucocorticoid agonists results in DNA fragmentation prior to cell death, these data suggest that 3-aminobenzamide potentiates the cytolytic response of sensitive cells to glucocorticoid agonists by inhibiting DNA excision repair mechanisms.

Adenosine Diphosphate↗
PubMed1990

Factors influencing choice of academic or practice careers in radiology.

Factors, both personal and job-related in nature, that influence career choice among radiology residents are identified. Twenty-six third and fourth year radiology residents at two separate locations, and 17 age-matched and sex-matched internal medicine residents completed a 30-minutes interview and rated themselves on a series of job-related competencies. Data were collected on five groups of variables: demographic data, residency-related variables, factors that influence career choice, self-descriptions, and personal competencies. The results indicate that residents who choose academic careers and those who plan to have private practice careers differ substantially in their reasons for career choice. An academic career is chosen because of its atmosphere, emphasis on research and specialized techniques, and opportunity for teaching. In contrast, private practice careers are selected because of the autonomy they allow, the accompanying lifestyle, and financial reimbursement.

Career Choice↗
PubMed1987

The effect of glucocorticoids on corticosteroid binding globulin.

To evaluate the effect of glucocorticoids on corticosteroid binding globulin (CBG), we measured the binding capacity and binding affinity of cortisol for CBG in normal subjects, patients receiving glucocorticoids and patients with Cushing's syndrome. Normal subjects had a mean binding capacity of 3.8 (+/- SD 0.7) X 10(-7) mol/l and mean binding affinity of 1.96 +/- 0.48 X 10(-8) M. Patients with Cushing's syndrome had a 40% decrease in binding capacity (2.3 +/- 0.4 X 10(-7) mol/l) compared to control subjects and significantly lower mean binding capacity than patients receiving pharmacological (2.9 +/- 0.6 X 10(-7) mol/l) and physiological doses of glucocorticoids (3.4 +/- 0.6 X 10(-7) mol/l) (P = 0.05 one-way analysis of variance). Patients with endogenous cortisol excess also had significantly lower mean binding affinity (1.54 +/- 0.37 X 10(-8) M) than normal subjects and glucocorticoid treated subjects. These changes suggest that both endogenous and exogenous glucocorticoids can modulate circulating levels of CBG and may have important implications for patients receiving steroid therapy.

Adrenal Insufficiency↗
PubMed1987

Use of [3H]cortivazol to characterize glucocorticoid receptors in a dexamethasone-resistant human leukemic cell line.

ICR 27 is a mutant derived from the glucocorticoid-sensitive human leukemic cell line CEM C7 that has been characterized as glucocorticoid receptor negative based on its ability to specifically bind [3H]dexamethasone ([3H]DEX). We used the pyrazolosteroid [3H]cortivazol ([3H]CVZ) to determine whether ICR 27 cells actually contain glucocorticoid receptors and, if so, whether these receptors can mediate physiological effects. Scatchard analysis of the binding of [3H]CVZ to cytosol from ICR 27 cells was consistent with a single class of receptors of uniform affinity (0.7 nM). Cytosolic [3H]CVZ complexes had a sedimentation coefficient of 4.6S on linear sucrose gradients and eluted from DEAE-cellulose columns at a potassium phosphate concentration of 250 mM. CVZ also competed with [3H]DEX mesylate for binding to a 96,000 mol wt protein. Incubation of ICR 27 cells with CVZ caused 50% growth inhibition and 50% maximal induction of glutamine synthetase activity at concentrations of 20 and 35 nM, respectively. Elution profiles of [3H]CVZ complexes from DEAE-cellulose columns showed that complexes formed upon thermal activation were relatively unstable, and little or no increase in binding of [3H]CVZ-receptor complexes to DNA-cellulose was observed. Thus, [3H]CVZ identifies functional glucocorticoid receptors in a cell line previously described as DEX resistant. Although the binding of [3H]CVZ to activated receptors in vitro appears unstable, high concentrations of CVZ may facilitate stabilization of activated complexes that can mediate both anabolic and catabolic effects.

Cell Division↗
PubMed1987

Effect of the antiprogesterone RU-38486 on meningioma implanted into nude mice.

Meningiomas have been shown to have steroid-binding proteins. In vitro, estradiol, progesterone, and the antiestrogen tamoxifen stimulate tumor growth. However, incubation of tumor cells with an antiprogesterone agent results in tumor inhibition. In this investigation, a human meningioma was implanted subcutaneously in athymic nude mice. Two treatment groups were established, one receiving the antiprogesterone agent RU-38486 (10 mg/kg/day in suspension) and the other receiving only vehicle. After 3 months, the tumor growth index (defined as the tumor volume at 3 months divided by the initial tumor volume) was 0.25 +/- 0.46 (mean +/- standard deviation) in the group receiving antiprogesterone and was 1.54 +/- 0.58 in the control group (p = 0.041). Further investigation of the effect of antiprogestational agents on the growth and hormone-binding proteins of other meningiomas will better define the mechanism of their effects.

Animals↗