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Biomedical subjects

J Carter

Publications and source records attributed to J Carter.

At least 109 records · Page 6Linked to original sources
PubMed1996

X-inactivation patterns in monozygotic and dizygotic female twins.

We have tested the hypothesis that contrasting X-inactivation patterns could be a trigger for monozygotic twinning in females. X-inactivation patterns were studied in umbilical cord tissue in 43 monozygotic twin pairs and 24 dizygotic twin pairs. Very skewed or non-random X-inactivation patterns were observed in both twins in six of the monozygotic twin pairs and in one of the dizygotic twin pairs. Contrasting X-inactivation patterns occurred in only one of the six monozygotic twin pairs. This does not support the original hypothesis. There is a trend to extreme skewing of X-inactivation pattern occurring more frequently in monozygotic twins.

Base Sequence↗
PubMed1996

Sebaceous carcinoma of the vulva: a case report and review of the literature.

Although sebaceous glands are prominent on the vulva, sebaceous carcinomas of the vulva rarely occur. In fact, there have been only two cases of sebaceous carcinomas of the vulva reported in the literature. Eighty percent of vulvar cancers are squamous in origin with human papillomavirus (HPV) DNA detected in approximately 60% of these cancers. We present a third patient with sebaceous carcinoma of the vulva and the first to our knowledge that has been analyzed for HPV DNA. The case report and a review of the literature are presented.

Adenocarcinoma, Sebaceous↗
PubMed1996

Effects of simulated high altitude on patients who have had radial keratotomy.

BACKGROUND: Previous studies documented diurnal myopic shifts in patients who have had radial keratotomy (RK). Recently, hyperopic shifts in these patients exposed to high altitude have been reported. A direct mechanical effect of reduced barometric pressure on surgically altered corneas has been theorized to cause this hyperopic shift. Another hypothesis implicates the effect of hypobaric hypoxia on the RK incisions. The authors examined the effect of a 6-hour exposure to decreased barometric pressure on 14 normal and 18 RK corneas. METHODS: Cycloplegic refraction, keratometry, corneal pachymetry, and tonometry were performed on seven control subjects and nine patients who have had RK. Measurements were obtained over 8 hours at sea level on day 1 of the study. Measurements were repeated on day 2 which included a 6-hour exposure to 12,000 feet simulated altitude in a hypobaric chamber. Results were compared between subjects and control subjects to determine the effect of a 6-hour exposure to decreased barometric pressure. RESULTS: There was no statistically significant difference in refraction or keratometry readings between control subjects and subjects who have had RK. Central corneal thickness decreased in the afternoon in RK eyes compared with control eyes. There was no clinically significant difference in intraocular pressure between subjects who have had RK and control subjects. CONCLUSIONS: A measurable hyperopic shift in RK corneas exposed to high altitude requires more than 6 hours to develop. A direct effect on corneal shape due to barometric pressure alone should produce a sudden change in refractive error. This study supports the hypothesis that a slow metabolic process is responsible for the previously documented hyperopic shifts induced by altitude. However, a barometric pressure effect requiring more than 6 hours to occur cannot be ruled out with the methodology used in this study.

Adult↗
PubMed1996

Effect of sustained inspiratory loading on respiratory sensation and CO2 responsiveness in normal humans.

1. To examine the effects of sustained resistive loading on the relationship between inspiratory effort sensation and respiratory drive (P0.1) and to determine if the change in CO2 responsiveness after sustained loading is accompanied by altered effort perception, hypercapnic responses were measured before, immediately after and 15 min after sustained resistive loading in seven subjects (six men, one woman). Sustained resistive loading was set to exceed a diaphragm tension-time index of 0.2. 2. Mean time to task failure during sustained loading was 17.7 min (range 12.5-22.5 min). The mean inspiratory effort sensation score rose from 3.4 (SEM 0.8) to 8.1 (0.8), whereas P0.1 fell from 29.5 (3.6) to 18.1 (3.6) cmH2O. 3. Immediately after loading the slopes of the ventilatory and sensory responses to CO2 fell (ventilatory response: before loading 16.7 (2.4) lmin-1kPa-1, immediately after loading 7.88 (2.18)lmin-1kPa-1; sensory response: before loading 1.95 (0.38) units/kPa; immediately after loading 1.12 (0.38) units/kPa; P < 0.05. Changes reverted to preloading levels by 15 min. 4. Sustained loading can lead to a dissociation between respiratory drive, as reflected by P0.1, and inspiratory effort sensation, and this disturbance can persist once the load is removed. Impaired sensory perception may be the primary determinant of the change in CO2 responsiveness seen after sustained resistive loading.

Adult↗
PubMed1996

Isolation and biological characterization of morphological transformation-sensitive Syrian hamster embryo cells.

Investigations were carried out designed to isolate and biologically characterize the subpopulation of cells within the Syrian hamster embryo (SHE) cell population which are sensitive to morphological transformation (MT). Biological cloning of MT-sensitive cells demonstrated that within the complex SHE cell population, MT-sensitive cells comprise approximately 27% of the clonally plateable cellular population. Importantly, MT-sensitive cells display MT rates of approximately 7% following benzo[a]pyrene exposure, a rate which falls to <1% with additional passage of the cells, indicating that the ability to undergo MT is a transient phenomenon. Biological characterization of the clonal MT-sensitive cells indicates that these cells are relatively undifferentiated, since they express both cytokeratins and vimentin and respond to a variety of stem cell growth and differentiation factors, although the majority appear to be committed progenitor cells, since they express either mesenchymal or epithelial cell characteristics. Together these data demonstrate that MT-sensitive cells comprise a subpopulation of the cells within the complex SHE cell population, that the ability to undergo MT is a transient phenomenon and that MT-sensitive cells are relatively undifferentiated committed progenitor stem-like cells, all of which gives rise to the hypothesis that MT is an alteration in the cellular differentiation state.

Animals↗
PubMed1996

Can hospice care be provided to people who live alone?

A growing number of people live alone; some in need of hospice care. Current approaches to providing care include the "patchwork" approach, institutional contracts, hospice day care, a demonstration program for people living alone, and supported housing. A brief discussion of each is presented, with a closing challenge to nursing to provide leadership and bold thinking to meet the changing need of these patients.

Forecasting↗
PubMed1996

Computed tomographic enteroclysis: one methodology.

RATIONALE AND OBJECTIVES: Computed tomography (CT) is limited in the assessment of partial small bowel obstruction (SBO). Enteroclysis is preferred but gives little direct information about the bowel wall, mesentery, or remote findings. Preliminary results of a combined CT enteroclysis (CT-E) methodology are reported. METHODS: Forty-eight patients with suspected partial SBO underwent a water soluble contrast enteroclysis followed immediately by CT. Pump rates at fluoroscopy and CT were 75 to 100 cc/min unless a high-grade obstruction was encountered at fluoroscopy. Shrake's criteria for complete, high-grade or low-grade partial SBO were used. RESULTS: The calculated dose per patient was 27 rad for CT-E as opposed to 32 rad with traditional enteroclysis. Site specific sensitivity and specificity for low-grade partial SBO, were 82.1% and 87.5%. One death was encountered in a patient with diffuse abdominal metastatic disease and complete obstruction. This was caused by vomiting and aspiration secondary to tube placement alone, CT-enteroclysis having been aborted. CONCLUSIONS: Computed tomographic enteroclysis is a diagnostic option for evaluation of low-grade partial SBOs. Pitfalls with this technique are encountered in decompressed torsions and hernias.

Abdominal Neoplasms↗
PubMed1996

Variations in plasma lipid concentration during examination stress.

The effect of psychological stress on plasma lipids was studied in 40 law students (20 men and 20 women). Plasma cholesterol, triglyceride, and apolipoprotein concentrations were examined at the beginning of the quarter and during the week before final examinations. Cortisol, blood pressure, and heart rate, and self-reports of stress and workload were also measured to verify that examinations were associated with increased stress levels. Perceived stress, perceived workload, and cortisol increased before examinations. Low density lipoprotein cholesterol (LDL-C) increased 5.8 +/- 13.9 mg/dL, and apolipoprotein B (apo B) increased 2.9 +/- 4.0 mg/dL. High density lipoprotein cholesterol decreased in women only. These changes were not due to changes in dietary intake or indexes of plasma volume. However, changes in cortisol and changes in LDL-C and apo B were associated, suggesting a neuroendocrine component to the effects. These results suggest that episodic, stressful situations may lead to potentially atherogenic changes in lipid and lipoprotein concentrations.

Journal Article↗
PubMed1996

Skin lesion with a fatal neurologic outcome (Degos' disease)

Degos' disease, a rare multisystem vasculopathy of unknown etiology, only occasionally involves the nervous system. We report the Mayo Clinic experience of the neurologic features of Degos' disease in a series of 15 patients. All 15 patients had the typical skin lesions of Degos' disease, confirmed by skin biopsy. Ten patients developed neurologic manifestations including fatal hemorrhagic or ischemic strokes (n=5), disabling polyradiculoneuropathy (n=1), and nonspecific neurologic symptoms without objective findings (n=4). Results of laboratory tests varied but none were pathognomonic of the disease. Long-term follow-up revealed death in six patients; nine patients were nearly asymptomatic. Immunosuppressive and antiplatelet agents were not of benefit. CNS infarcts and hemorrhages with intravascular thrombi, but without evidence of vasculitis, were characterized features at autopsy.

Adolescent↗
PubMed1996

Predictive value of eosinophilia for neutropenia during clozapine treatment.

BACKGROUND: Myelotoxicity continues to hinder the widespread use of clozapine in the United States. It has been theorized that eosinophilia predicts later agranulocytosis and that agranulocytosis occurs due to an immunologic mechanism. Our study compares the rates of these dyscrasias in clozapine-treated patients and a control group. METHOD: Forty-one patients taking clozapine and 29 patients taking haloperidol were monitored for a period of 6 months. Rates of eosinophilia and neutropenia were compared between the two treatment groups. RESULTS: Treatment-emergent eosinophilia occurred frequently in both haloperidol- and clozapine-treated patients. No significant difference was seen between groups in the incidence of eosinophilia and neutropenia. CONCLUSION: We find no statistical difference between the rates of eosinophilia or neutropenia in haloperidol- and clozapine-treated patients. This study does not support the use of eosinophilia as a reliable predictor of neutropenia.

Adult↗
PubMed1996

Factor V Leiden polymorphism (FV Q506) in patients with ischaemic heart disease, and in different populations groups.

A point mutation in the factor V gene (FV Q506) renders factor V resistant to inactivation by activated protein C. The frequency of this mutation is known to be significantly increased in patients with thrombophilia. There are conflicting reports on the significance of the polymorphism in patients with ischaemic heart disease. We determined the frequency of FV Q506 in a control Caucasian population, and compared it with 192 Caucasian patients admitted to coronary care and assessed as having myocardial infarction (MI) or unstable angina plus previous MI. There was no significant difference between the two groups. A cohort of 105 asymptomatic Afro-Caribbeans showed a much reduced frequency of the polymorphism.

Black People↗
PubMed1995

Factors predictive of the need for levodopa therapy in early, untreated Parkinson's disease. The Parkinson Study Group.

OBJECTIVE: To identify characteristics of patients with early, untreated Parkinson's disease that are the most important predictors of rapid functional decline. DESIGN: Prospective observational study of a cohort of 800 patients with early, untreated Parkinson's disease who were involved in a multicenter, randomized, double-blind, controlled clinical trial of selegiline hydrochloride (L-deprenyl) and vitamin E (alpha-tocopherol). PRIMARY OUTCOME VARIABLE: Time from randomization to the onset of disability that necessitated levodopa therapy (end point), as judged by the enrolling investigator. METHODS: Stepwise Cox regression was used in combination with clinical judgment to identify the most important independent baseline predictors of the primary end point among a host of variables, including treatment with selegiline and vitamin E, global and specific clinical measures of disease severity, demographic variables, and neuropsychological test results. RESULTS: In addition to selegiline treatment and global disease severity measures, such as the stage according to the criteria of Hoehn and Yahr, impaired domestic capacity, and the activities of daily living score, the complex of postural instability/gait difficulty and bradykinesia were found to be the factors that were most highly associated with the risk of reaching the end point. CONCLUSIONS: The findings suggest that patients with Parkinson's disease whose early clinical presentation includes either postural instability/gait difficulty or bradykinesia are at high risk for rapid functional decline.

Adult↗
PubMed1995

Factors affecting dropout rate from cognitive-behavioral group treatment for bulimia nervosa.

The aim of this study was to retrospectively identify clinical variables assessed prior to treatment which were predictive of patients' dropping out versus completing a 10 week group cognitive-behavioral treatment program for bulimia nervosa. Following a lengthy initial assessment, 81 women meeting DSM-III-R criteria for bulimia nervosa (BN) were referred to one of twelve 10-week groups of 8 to 12 patients having bulimic symptoms. The dropout rate for those meeting full DSM-III-R criteria for BN was found to be 28.7%. A series of seven discriminant function analyses were performed to determine whether dropouts differed from completers in terms of depression, anxiety, difficulties in trust and relating to others, bulimic symptom severity, family environment, weight history and symptom duration and severity of bulimic cognitions. Of these, only the factor assessing difficulties trusting and relating to others was found to significantly discriminate dropouts from completers. Implications of the findings are discussed in terms of clinical and research relevance in the field of eating disorders.

Adult↗
PubMed1995

Diffuse arterial thrombosis in a young man with elevated lipoprotein(a) and minimal atherosclerosis.

An increased incidence of premature atherosclerotic arterial occlusive disease was recently reported in young adults. This condition is characterized by early occurrence of severe symptoms, lower incidence of typical cardiovascular risk factors for atherosclerosis, different natural course of arterial disease vis-a-vis older population, and poor outcome of a standard treatment. This report describes a young man with aggressive arterial occlusive disease in the lower extremities and symptom-free occlusions of coronary and renal arteries in association with high levels of lipoprotein(a). Microscopic early atherosclerotic changes were noted in the occluded arteries of the amputated leg. Premature atherosclerotic arterial occlusive disease in young adults has different clinical and pathological patterns, necessitating a different approach for evaluation and treatment.

Adult↗
PubMed1995

Fetal mouse susceptibility to transplacental carcinogenesis: differential influence of Ah receptor phenotype on effects of 3-methylcholanthrene, 12-dimethylbenz[a]anthracene, and benzo[a]pyrene.

Genetic backcrosses of C57BL/6 and DBA/2 mice were used to examine the influence of maternal and fetal polymorphisms at the Ahr locus on susceptibility to transplacental carcinogenesis by 3-methylcholanthrene, 7,12-dimethylbenz[a]anthracene, and benzo[a]pyrene. (C57BL/6 x DBA/2) F1 mothers were backcrossed to DBA/2 males, and DBA/2 females to F1 males to produce both Ahr-responsive (Ah+) and nonresponsive (Ah-) fetuses carried by mothers that were themselves either Ah+ or Ah-. 3-Methylcholanthrene was given intragastrically on gestation days 13-18 and 7,12-dimethylbenz[a]anthracene or benzo[a]pyrene on day 17 as a single intraperitoneal dose. Ahr phenotype was determined by the zoxazolamine sleeping time test after beta-naphthoflavone pretreatment at 6 weeks of age. The offspring were examined for tumours at 1 year. Both 3-methylcholanthrene and 7,12-dimethylbenz[a]anthracene treatments resulted in a two- to five-fold greater incidence and multiplicity of lung and liver tumours in the Ah+ offspring compared with that in Ah- littermates. By contrast, there was no difference between Ah+ and Ah- offspring with regard to numbers of tumours caused by benzo[a]pyrene. Maternal Ahr phenotype appeared to play a role also, in that the offspring of the Ahr-responsive F1 mothers developed fewer tumours per unit dose than those of the nonresponsive DBA/2 mothers. The effect of maternal phenotype on risk was three- to five-fold. Fetal and maternal phenotype combined yielded a 10- to 20-fold risk differential for transplacental carcinogenesis by the methylated compounds, with greatest risk experienced by responsive fetuses in nonresponsive mothers, and least by nonresponsive progeny of responsive mothers.

9,10-Dimethyl-1,2-benzanthracene↗