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Biomedical subjects

R Holloway

Publications and source records attributed to R Holloway.

At least 19 recordsLinked to original sources
PubMed1996

Cognitive performance and regional brain volume in human immunodeficiency virus type 1 infection.

BACKGROUND: Brain atrophy has been reported to occur in advancing human immunodeficiency virus (HIV) infection, particularly in patients with HIV-related dementia. Atrophy of the caudate region, as assessed by magnetic resonance imaging measures, has been reported to correlate with cognitive impairment in patients with HIV infection; however, differences in the severity of HIV-induced immunosuppression may have contributed to these findings. OBJECTIVE: To determine the relationship between regional brain volumes and cognitive performance in individuals with HIV infection. PATIENTS AND METHODS: We evaluated 11 patients with advanced HIV disease by using neuropsychologic tests and quantitative magnetic resonance imaging volume analysis. SETTING: University hospital, involving patients from a clinical trial. RESULTS: Caudate volume, expressed as a ratio of total intracranial volume, correlated with performance on the Trails A and Grooved Pegboard tests, but not with other tests of memory, motor speed, or mood (adjusted for age and education). Hippocampal volume did not correlate with any of the neuropsychologic tests. CONCLUSIONS: Caudate volume in patients with advanced HIV disease is associated with poor performance on neuropsychologic tests of complex motor and sequencing skills. Hippocampal volume does not appear to be related to impairment on neuropsychologic tests. These findings are independent of the degree of immunosuppression and the overall extent of brain atrophy; however, these results must be interpreted with some caution, given the limited sample size.

Adult↗
PubMed1995

Effect of atropine on the frequency of reflux and transient lower esophageal sphincter relaxation in normal subjects.

BACKGROUND & AIMS: Low basal lower esophageal sphincter (LES) pressure is believed to be an important mechanism of reflux. The effects of atropine on the frequency and mechanisms of gastroesophageal reflux under the experimental conditions of a low basal LES pressure in 13 normal subjects were studied. METHODS: LES pressure, esophageal pressures, esophageal pH, and crural diaphragm electromyogram were recorded simultaneously in the postprandial period for 30 minutes before and two 30-minute periods after the injection of atropine. RESULTS: Atropine reduced the basal LES pressure from 16.4 +/- 3 to 8.7 +/- 2 mm Hg. The frequencies of reflux in the control and two postatropine periods were 3.5 +/- 0.5, 0.4 +/- 0.2, and 0.8 +/- 0.3, respectively (P < 0.05). The frequencies of transient LES relaxations decreased from 3.5 +/- 0.5 in the control to 0.4 +/- 0.2 and 1.5 +/- 0.4 in the two postatropine periods (P < 0.05). Transient LES relaxation and associated inhibition of the crural diaphragm was the major mechanism of reflux under conditions of low LES pressure induced by atropine. CONCLUSIONS: Atropine-induced low LES pressure does not predispose to reflux in normal healthy subjects. Atropine reduces the frequency of reflux by its inhibitory effect on the frequency of transient LES relaxation.

Adolescent↗
PubMed1992

Radiotherapy of malignant subdiaphragmatic implants in advanced ovarian carcinoma: a new technique.

We report the development of a new technique using remote afterloading intraoperative radiation therapy to deliver a tumoricidal dose to diaphragmatic tumor implants. A multi-positional lucite applicator was designed based on anatomic studies of the diaphragmatic surface to accommodate a high dose rate iridium source in a series of needles placed 1.5 cm apart. The applicator curvature can vary from planar to full accommodation of the diaphragmatic surface with a constant source to surface distance of 0.5 cm. The applicator has been piloted in three patients with ovarian carcinoma with residual subdiaphragmatic disease found at second look laparotomy, to deliver a dose of 1,500 to 2,000 cGy at 0.5 cm. Tolerance of the diaphragm and hepatic surface has been excellent. There were no postoperative complications and no deterioration in liver function studies. The additional postoperative external beam irradiation directed with the aid of surgically placed clips and gated to respiratory movements permits achievement of a tumoricidal dose while limiting the treated volume and related toxicities.

Brachytherapy↗
PubMed1991

Obstructive sleep apnoea in patients with dilated cardiomyopathy: effects of continuous positive airway pressure.

The combined effects of negative intrathoracic pressure swings during obstructive sleep apnoeas (OSAs) and increased sympathetic nervous system tone associated with hypoxia and sleep arousal may lead to pulmonary oedema or left-ventricular hypertrophy. Therefore, we have done a study of patients with congestive heart failure secondary to idiopathic dilated cardiomyopathy to see whether OSA could contribute to impaired left-ventricular function and to assess nasal continuous positive airway pressure (NCPAP) for treatment. Eight men (aged 29-69 years) took part in the study; all were obese. Left-ventricular ejection fraction (LVEF) was measured while on stable medication and then 4 weeks after the start of nocturnal NCPAP. NCPAP was associated with abolition of OSA (mean [SE] number of apnoeas and hypopnoeas per hour of sleep 54.1 [7.2] and 1.0 [0.4] for pretreatment and NCPAP nights, respectively, p less than 0.0001). Mean (SE) LVEF increased from 37 (4)% pretreatment to 49 (5)% after four weeks' NCPAP therapy (p less than 0.0001). Withdrawal of NCPAP for 1 week in four patients was associated with a reduction in LVEF from 53 (6)% to 45 (5)% (p less than 0.001). OSA may contribute to impaired left-ventricular function in some patients with dilated cardiomyopathy of otherwise unknown origin, and reversal of OSA by NCPAP can lead to significant improvement in LVEF.

Adult↗
PubMed1990

Completion rate and reliability of the self-administered genogram (SAGE).

The self-administered genogram (SAGE) has been developed to increase the use of genograms in clinical practice. The purpose of this study was to assess the completion rate of the SAGE and its test-retest reliability. Eleven women patients completed the SAGE on two occasions, three months apart. The completion rates of the two testings were similar, and high degrees of reliability were observed. Reliability varied by type of information and generation of family members. The SAGE appears to be an efficient tool for obtaining complete and consistent information about family structure, demographics and life events. The utility of the SAGEs with regard to family health information is as yet unexplored.

Aged↗
PubMed1984

Two classes of cAMP analogs which are selective for the two different cAMP-binding sites of type II protein kinase demonstrate synergism when added together to intact adipocytes.

Twenty-five cyclic nucleotide analogs were tested individually to act as lipolytic agents and to activate adipocyte protein kinase. The lipolytic potency of individual analogs correlated better with their Ka for protein kinase and their lipophilicity rather than with either parameter alone. Some of the most potent lipolytic analogs had I50 values for the particulate low Km cAMP phosphodiesterase suggesting that their effect was not due to raising endogenous cAMP levels through inhibition of phosphodiesterase. The most potent lipolytic analogs contained a thio moiety at the C-8 or C-6 position. These analogs exhibited concave upward dose-response curves. At high concentrations, some analogs were as effective as optimal concentrations of epinephrine in stimulating glycerol release. The regulatory subunit of protein kinase has two different intrachain cAMP-binding sites and cAMP analogs modified at the C-8 position (C-8 analogs) are generally selective for Site 1 and analogs modified at the C-6 position (C-6 analogs) are generally selective for Site 2 (Rannels, S. R., and Corbin, J. D. (1980) J. Biol. Chem. 255, 7085-7088). Thus, C-8 and C-6 analogs were tested in combination to stimulate lipolysis in intact adipocytes and to activate protein kinase in vitro. Each process was stimulated synergistically by a combination of a C-6 and C-8 analog. Two C-8 analogs or two C-6 analogs added together did not cause synergism of either process. For both lipolysis and protein kinase activation, C-8 thio analogs acted more synergistically than C-8 amino analogs when incubated in combination with C-6 analogs, a characteristic of type II protein kinase. It is concluded that the observed synergism of lipolysis is due to binding of cAMP analogs to both intrachain sites and that it is the type II protein kinase isozyme which is responsible for the lipolytic response.

Adipose Tissue↗
PubMed1983

Lactic acidosis in a patient with acute leukemia.

Lactic acidosis is a rare but potentially fatal complication of acute leukemia. The terminal phase of acute leukemia in a 22-year-old woman, heralded by lactic acidosis, is described in order to focus attention on the occurrence of this metabolic disturbance in the absence of overt manifestations of acute leukemia. As reported in other cases, the lactic acidosis in our patient responded poorly to bicarbonate therapy but dramatically to antileukemic chemotherapy. The pathogenesis of the lactic acidosis is unclear but it may be the result of an undefined 'paraneoplastic' metabolic disturbance induced by the leukemic cells.

Acidosis↗
PubMed1976

Pulmonary function after recovery from the adult respiratory distress syndrome.

Eight adult patients with acute respiratory distress syndrome were treated with positive end-expiratory pressure (PEEP) ventilation. The results of detailed examinations of pulmonary function in these eight patients obtained after different periods of time following discharge from the respiratory care unit were analyzed to determine the degree of disturbances in pulmonary function. For comparison, examinations of pulmonary function were also performed on two patients who were treated with zero end-expiratory pressure ventilation. This follow-up study showed remarkably few abnormalities. Whe present, restrictive disturbances in pulmonary function, especially decreased static compliance and diffusing capacity, were found. No correlation was found between the pulmonary-function results of the eight patients and the duration of the PEEP treatment, nor between the results and the time interval between treatment at the respiratory care unit and the moment of the pulmonary function studies.

Adolescent↗