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Biomedical subjects

S Marshall

Publications and source records attributed to S Marshall.

At least 73 records · Page 4Linked to original sources
PubMed1997

Neuropsychological performance of HIV-1 infected men with major depression. HNRC Group. HIV Neurobehavioral Research Center.

This study sought to determine if human immunodeficiency virus-type 1 (HIV-1) infected depressed men were more likely to be neuropsychologically impaired than their nondepressed counterparts. Subjects were 47 HIV-1 infected men who met DSM-III-R criteria for current major depressive disorder (MDD) and 47 HIV-1 infected nondepressed male controls (M age = 34.2 years) equated on HIV-1 disease severity, demographics, and drug use. The psychiatric interview included the Structured Clinical Inventory for the DSM-III-R, and Hamilton Rating Scale for Depression. The neuropsychological battery included tests covering 8 functional domains based on an expanded Halstead-Reitan Battery. The medical assessment included a history and physical examination, immunologic staging, and evaluation of prescription and recreational drug use. Prevalence of global neuropsychological impairment in the two groups (depressed vs. control) did not differ [53% vs. 38% respectively; chi 2(1, N = 94) = 2.11, p > .05]. While syndromically depressed patients performed less well than nondepressed individuals on memory tests [delayed retention portions of the Story Memory Test: F(1,91) = 5.34, p < .05; and Figure Memory Test: F(1,90) = 4.16, p < .05], the majority of depressed participants (64%) did not have clinically impaired memory. No relationship between neuropsychological impairment and severity of depression was observed. The results suggest that, while HIV-1 infected men with major depression may perform more poorly than nondepressed men on some aspects of memory tasks, they are not more likely to evidence clinically significant neurocognitive impairment.

Adult↗
PubMed1995

Availability of thrombolytic therapy in rural Newfoundland and Labrador.

OBJECTIVE: To determine the availability of thrombolytic therapy in rural Newfoundland and Labrador. DESIGN: Self-administered questionnaire mailed to staff at health care facilities. Respondents were sent two reminders by mail, and questionnaires not returned were completed through telephone interviews. SETTING: Rural health care facilities, including hospitals, 24-hour clinics and satellite clinics. PARTICIPANTS: All chief medical officers, nursing supervisors and administrators in the 34 government-funded rural health care facilities in Newfoundland and Labrador. OUTCOME MEASURES: Number of facilities offering thrombolytic therapy to patients with acute myocardial infarction (AMI) in 1992. For each facility: number of patients presenting with AMI during that year, number of these patients who received thrombolytic therapy, number of staff trained in advanced cardiac life support, travel time to the nearest referral centre, population served and number of beds. RESULTS: Of the 34 rural health care facilities in Newfoundland and Labrador, 91% (31/34) responded to the survey. Thrombolytic therapy was offered in 93% (13/14) of the rural hospitals, 22% (2/9) of the 24-hour clinics and none of the single-physician satellite clinics. In 1992, 390 patients with AMI presented to these health care facilities; 39% of these patients presented to facilities that did not offer thrombolytic therapy. CONCLUSIONS: Thrombolytic therapy has been successfully introduced in many of the rural and isolated health care facilities in Newfoundland and Labrador. An important factor in this success is continuing medical and nursing education on the effectiveness of thrombolytic therapy and the skills needed to provide it. Cost-effectiveness data are needed to determine whether it is reasonable to offer this therapy in isolated, low-volume clinics. More research on the outcomes in patients receiving thrombolytic therapy in rural facilities is also needed.

Humans↗
PubMed1995

Colonic spreading of a non-chlorofluorocarbon mesalazine rectal foam enema in patients with quiescent ulcerative colitis.

BACKGROUND: Rectal foam enemas provide for drug delivery to the distal colon for treatment of left sided ulcerative colitis. However, currently available formulations contain chlorofluorocarbons which are due to be phased out in the near future. The objective of this study was therefore to determine the degree of dispersion of a newly developed non-chlorofluorocarbon rectal foam preparation in ulcerative colitis patients. METHODS: This was an open label non-controlled study of a single administration of a mesalazine foam enema (two actuations containing 2 g of mesalazine in approximately 120 mL foam) in 10 patients with quiescent ulcerative colitis. Spreading of the 99mTc-labelled foam enema was assessed over a 4-h period by the non-invasive technique of gamma scintigraphy. RESULTS: All patients retained the enema for the full 4-h imaging period. In nine out of the 10 patients, the enema was observed to spread as far as the descending colon and on average 23% of the dose was present in the descending colon at 4 h post-dose. CONCLUSIONS: The extent of spreading observed in the study supports the use of the formulation in the treatment of left sided ulcerative colitis.

Aminosalicylic Acids↗
PubMed1995

Insulin resistance after hypertension induced by the nitric oxide synthesis inhibitor L-NMMA in rats.

To explore the relationship between insulin resistance and hypertension, we examined whether acute induction of hypertension can engender insulin resistance. For this purpose we measured rates of insulin-mediated glucose uptake in awake unstressed rats with the euglycemic hyperinsulinemic (12 microns.kg-1.min-1) clamp technique during infusions of saline alone or after induction of hypertension by bolus administration of NG-monomethyl-L-arginine (L-NMMA, 30 and 15 mg/kg), a competitive inhibitor of nitric oxide synthase. Arterial pressure was approximately 20% greater with L-NMMA bolus than with saline alone. Isotopically determined steady-state rates of glucose uptake were 36 +/- 1 mg.kg-1.min-1 during saline alone and 26 +/- 2 and 19 +/- 1 mg.kg-1.min-1 with low- and high-dose L-NMMA (P < 0.001 vs. saline), respectively. To rule out that insulin resistance induced by L-NMMA was adrenergically mediated, clamp studies were repeated with alpha- and beta-blockade. Rates of glucose uptake remained approximately 20% below those observed with saline alone (P < 0.001). A significant inverse correlation was observed between the height of the blood pressure and the rate of glucose uptake (r = 0.32, P = 0.04). In conclusion, acute induction of hypertension with L-NMMA can cause marked insulin resistance. We postulate that reduced skeletal muscle perfusion and/or sympathetic nervous system activation may contribute to insulin resistance induced by L-NMMA.

Animals↗
PubMed1995

Middle management training: investment in the future.

Most home care agencies are in desperate need of good middle-level managers. The solution seems to lie in recruiting or promoting people with potential, teaching them the necessary skills, and imparting to them the motivation they need to be successful.

Administrative Personnel↗
PubMed1994

Potent and selective inhibition of human nitric oxide synthases. Inhibition by non-amino acid isothioureas.

S-Ethylisothiourea was a potent competitive inhibitor of human nitric oxide synthase (NOS), with Ki values of 17, 36, and 29 nM for the inducible (i), endothelial (e), and neuronal (n) isozymes, respectively. Unlike some potent inhibitors of NOS, no time dependence was observed. S-Ethylisothiourea was not a detectable substrate for eNOS. S-Ethylisothiourea was also a potent inhibitor of mouse iNOS (Ki value of 5.2 nM), and its binding perturbed the spectrum of iNOS consistent with its altering the environment of the bound heme. The optimum binding of S-ethyl- and S-isopropylisothiourea relative to 70 other analogs suggested that these alkyl substitutions fit into a small hydrophobic pocket. Most isothioureas were 2-6-fold selective for the human iNOS (Ki for iNOS versus Ki for eNOS), with one being 19-fold selective. The cyclized mimics of S-ethylisothiourea, 2-NH2-thiazoline, and 2-NH2-thiazole, were also competitive inhibitors of human NOS. A third structural class of inhibitors, bisisothioureas, were, in general, the most selective in their inhibition of human iNOS. S,S'-(1,3-Phenylenebis(1,2-ethanediyl))bisisothiourea was 190-fold selective (Ki value of 0.047 microM against iNOS versus 9.0 microM against eNOS). These results demonstrate that potent and selective inhibition of human NOS isozymes is achievable.

Amino Acid Oxidoreductases↗
PubMed1994

Radon in outdoor air in Nevada.

Measurements of radon at 50 sites with varying geology indicate that outdoor air in Nevada is comparable to that measured nationwide by Hopper et al. (1991). The statewide median of 15 Bq m-3 (0.4 pCi L-1) is essentially the same as the nationwide median. The range is considerable: from 2.6-52 Bq m-3 (0.07-1.40 pCi L-1). Variations in these measurements can generally be correlated with different concentrations of radon in soils and uranium and its progeny in rocks. Silica-rich igneous rocks (rhyolites and granites) appear to be the main sources of high levels of radon in outdoor air in Nevada. Concentrations of radon in outdoor air generally correlate with levels of radon in soil gas. Measurements taken from heights of 0.5, 1.0, and 2.0 m above the ground suggest that radon in outdoor air reflects the local geology throughout this range of heights. Towns for which > 20% of the homes have indoor-air radon concentrations > 48 Bq m-3 (4 pCi L-1) generally have relatively high soil-gas radon, relatively high outdoor-air radon, or both.

Air Pollutants, Radioactive↗
PubMed1994

Characteristics of abstinent substance abusers who first sought treatment in adolescence.

A survey was given to 141 male and female substance abusers who had eleven or more months of continuous abstinence and first sought treatment in adolescence in an attempt to add to the limited knowledge of known variables associated with successful adolescent response to clinical and community-based treatment. Results were used to create a composite of successfully abstinent adolescents. Generally, parental alcoholism and most drug use patterns were not related to the number of relapses or length of sobriety. Most of the respondents entered twelve-step programs via treatment. The only two variables that were significantly correlated with the dependent measures of more relapses and less overall sobriety were getting high for the first time at a younger age and polydrug abuse. There were about five times more adoptees represented in this sample than would be statistically expected. Implications for adolescent substance abuse diagnosis and prognosis are discussed.

Adolescent↗
PubMed1994

Improvised automatic lung ventilation for unanticipated emergencies.

OBJECTIVES: To design an improvised circuit that can be used to extend the capability of a single ventilator to ventilate two or more patients and that can be assembled from readily available parts in times of unanticipated emergency. DESIGN: Research and development, followed by technical analysis and evaluation. SETTING: Biomedical laboratory. MEASUREMENTS AND MAIN RESULTS: We describe two circuits that can be assembled from readily available inexpensive components to function as improvised ventilators. One circuit requires only a central mushroom valve driver and an additional source of fresh gas for each patient. The other circuit is configured as a number of secondary circuits in parallel, connected to a single ventilator. We constructed and tested the circuits using mechanical lung simulators. The secondary circuit configuration was more efficient in terms of fresh gas usage, but was more complex regarding operation and trouble-shooting. CONCLUSIONS: These two improvised circuits can extend the capability of a standard volume-cycled ventilator to provide automatic ventilation of the lungs in times of disaster.

Emergencies↗
PubMed1993

A rapid biochemical method for measuring antigen-induced pulmonary eosinophil margination in allergic guinea pigs.

The ability of purified guinea pig peritoneal eosinophils (EOS) to oxidise 3,3',5,5'-tetramethylbenzidine (TMB) was assessed in the presence/absence of Br- (3 mM), and compared with that of unpurified elicited peritoneal polymorphonuclear leukocytes (PMN). Br- selectively stimulated EOS peroxidase activity in a cell number-dependent manner, which was not significantly affected by the presence of diluted lung homogenate. By comparison with the peroxidase activity of added purified EOS, lung parenchyma homogenate from naive guinea pigs was estimated to contain 1.04 +/- 0.18 x 10(5) cells/mg wet tissue (n = 6), a value comparable to those calculated from published histological analyses. This was not significantly increased by ovalbumin (OA) allergen inhalation in unsensitised guinea pigs (1.4 x 10(5) EOS/mg), but was increased two-fold over the latter control to 3.0 +/- 0.18 x 10(5) cells/mg after 17 h in animals sensitised by a single injection of OA and subsequently exposed to an aerosol of bronchoactive allergen (n = 13, p < 0.05). Similar results were obtained in a parallel study using bronchoalveolar lavage (saline challenge, 20.2 +/- 2.2% EOS in lavage fluid; OA challenge, 47.1 +/- 3.6% EOS; n = 6, p < 0.05). In animals that had been doubly sensitised (two injections) to OA, the pulmonary eosinophilic response measured biochemically was more pronounced (4.9 +/- 0.2 x 10(5) cells/mg) and was significantly greater than both a non-specific protein inhalation in this sensitisation group, and OA inhalation in singly sensitised animals (n = 12, p < 0.05). Sera from the latter group was shown to contain five times less specific anti-OA IgG than the doubly sensitised animals, suggesting that EOS margination in guinea pigs is proportionate to the animals' immune status for a defined immunological challenge. These data demonstrate that in vivo EOS migration into the whole guinea pig lung can be rapidly determined by biochemical methods, and thus facilitate the in vivo assessment of novel therapeutic agents against the eosinophilic inflammation characteristic of human allergic asthma.

Animals↗
PubMed1993

Mortality and social class in Maori and nonMaori New Zealand men: changes between 1975-7 and 1985-7.

AIMS: Social class mortality differences in Maori and nonMaori New Zealand men aged 15-64 years have previously been examined for the period 1975-7. The analysis has now been repeated for the period 1985-7 in order to examine changes over time. METHODS: Numerator data were obtained from national death registrations and denominator data were obtained from the 1976 and 1986 censuses. These were used to calculate age-standardized death rates in Maori and nonMaori. RESULTS: Mortality declined by 28% in Maori and 14% in nonMaori between 1975-7 and 1985-7. The death rate for diseases amenable to medical intervention fell by 54% in Maori and 23% in nonMaori, but the Maori death rate was still 2.8 times the nonMaori death rate, whereas the relative risk for nonamenable causes was only 1.4. CONCLUSIONS: Some progress has been achieved in reducing ethnic differences in mortality in New Zealand men, but substantial differences remain for diseases which are amenable to medical intervention (including chronic rheumatic heart disease, hypertensive heart disease, and tuberculosis). It is likely that these differences reflect poor access to culturally safe and appropriate health care in Maori people.

Adolescent↗
PubMed1993

Mucosal injury and inflammation in a model of chronic granulomatous colitis in rats.

BACKGROUND: The objective of this study was to characterize the acute and chronic inflammation induced by the intramural injection of peptidoglycan-polysaccharide (PG-PS) into the distal colon of genetically susceptible rats. METHODS: Blood-to-lumen clearance of 51Cr-ethylenediaminetetraacetic acid, colonic myeloperoxidase activity, colon weight, and plasma nitrite and nitrate levels were determined to quantitate colonic mucosal injury, inflammation, and nitric oxide (NO) production, respectively. RESULTS: Intramural injection of PG-PS into the distal colon produced a local biphasic inflammatory response composed of an acute episode 3 days after injection; this was followed by a spontaneous reactivation of chronic granulomatous colitis manifested by colonic thickening, adhesions, and infiltration of the submucosa and muscularis propria with macrophages, neutrophils, and lymphocytes at 3-4 weeks. Mucosal ulcers were evident only at 3 weeks, but hepatic nodules, splenic necrosis, and arthritis were evident at both 3 and 4 weeks after PG-PS injection. PG-PS produced significant increases in colonic mucosal permeability, myeloperoxidase activity, and plasma nitrite and nitrate levels at 3 weeks postinjection compared with controls. PG-PS stimulated the production of nitrite by elicited peritoneal macrophages and neutrophils in vitro. CONCLUSIONS: PG-PS produces a chronic granulomatous colitis in rats; this colitis is characterized by enhanced NO production.

Amino Acid Oxidoreductases↗