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Biomedical subjects

S Hall

Publications and source records attributed to S Hall.

At least 217 records · Page 12Linked to original sources
PubMed1986

Stress in social and family relationships during the medical residency.

A study of stress during residency training involved data analysis of questionnaires completed by 108 residents and fellows in internal medicine. Over 40 percent of the respondents experienced important problems with their spouse or partner. Of these, 72 percent believed that these problems were due to the residency, and 61 percent reported that their spouse or partner agreed with this assessment. Only 21 percent of the residents with relationship problems felt that their hospital work was being affected negatively. A multiple regression analysis showed that 10 variables accounted for 50 percent of the variance in predicting relationship stress. The results suggest that scheduling and structural changes in residencies are necessary in order to reduce stress among residents. Perhaps equally important is the finding that stress can be buffered by family relationships and social contact. The authors conclude that social support systems need to be fostered during the residency.

Adult↗
PubMed1986

Effects of saxitoxin analogues and ligand competition on sodium currents of squid axons.

Saxitoxin (STX) and several STX analogues from dinoflagellates (genus Protogonyaulax) block sodium conductance in squid giant axons with variable potencies. Toxins, analyzed under voltage clamp, are 21-sulfosaxitoxin, 21-sulfosaxitoxin 11 alpha-hydroxysulfate, 21-sulfosaxitoxin 11 beta-hydroxysulfate, (B1, C1, C2, respectively) and gonyautoxins 2 and 3. The potency sequence for the toxins examined is STX greater than gonyautoxin 3 greater than B1 greater than C2 greater than gonyautoxin 2 much greater than C1. Guanidine, when substituted for sodium in external seawater, reduced the potency of STX to block inward current but did not affect tetrodotoxin activity. Methylguanidine also reduced the ability of STX to block outward sodium current. Inhibitory constants for guanidine and methylguanidine were 116 and 187 mM, respectively. Competition can be explained by binding at or near the toxin binding site but not by surface potential alteration.

Amphibian Proteins↗
PubMed1986

Takayasu's arteritis and juvenile rheumatoid arthritis.

We describe a patient with the onset of polyarticular juvenile rheumatoid arthritis at age 7; she developed Takayasu's arteritis 12 years later. Her arthritis had been inactive until 15 months before the diagnosis of Takayasu's arteritis. The association of arthritis and Takayasu's arteritis is discussed.

Aortic Arch Syndromes↗
PubMed1986

How lupoid is lupoid hepatitis?

The records of 89 patients with hepatitis B surface antigen, negative severe chronic active hepatitis and antinuclear antibody (ANA) positivity were reviewed to assess the degree of clinical similarity between this disorder and systemic lupus erythematosus (SLE). Although immunologic abnormalities, such as antibodies to native DNA and positive lupus erythematosus cell preparations were common, few patients with ANA positive chronic active hepatitis had clinical features to suggest SLE. The 1971 preliminary criteria and the 1982 revision of the American Rheumatism Association criteria for classification of SLE were 93 and 91% specific, respectively. We conclude that despite laboratory similarities, ANA positive chronic active hepatitis and SLE differ substantially in their clinical presentations.

Adolescent↗
PubMed1986

Determinants of social proximity in Japanese quail (Coturnix coturnix japonica): male behavior.

Following opportunity to copulate with a female housed in an adjacent compartment, male Japanese quail spent 64% of their time near a window that provided visual access to the female (Experiment 1). This social proximity behavior persisted for at least 2 weeks of continual exposure to the window despite lack of further physical access to the female (Experiment 2) and was evident at all daylight hours (Experiment 3). Female Japanese quail stimulated more proximity behavior in male conspecifics than did other male Japanese quail or birds of other species (Experiments 4 and 5). However, many characteristics of the female quail were not critical. The female quail did not have to be previous sexual partners, familiar, sexually experienced, or reproductively competent to stimulate proximity behavior in males (Experiments 4 and 5). Experiment 6 demonstrated that the social proximity behavior was primarily a response to the visual aspects of the females. The results are discussed in relation to mate-guarding and surveillance behavior, and implications of the data for sexual classical conditioning of male Japanese quail are noted.

Animals↗
PubMed1985

A simplified liquid chromatography and electrochemical detection method for measurement of plasma noradrenaline.

A simplified, sensitive, and reliable method for the determination of noradrenaline (NA) in plasma using high-performance liquid chromatography and electrochemical detection is described. Investigations on the stability of NA in plasma and whole blood have effected an improvement in the method for collection and extraction of NA from plasma. Recycling the mobile phase and the elimination of the addition of antioxidants during the alumina extraction has resulted in savings in the costs of reagents and assay preparation time while retaining a recovery rate of 60% and improving detector response. The sensitivity of the assay for NA was 20 pg/ml of plasma using carbon paste prepared in the laboratory.

Antioxidants↗
PubMed1985

A controlled trial of fixed versus tailored calorie intake in patients receiving intravenous feeding after abdominal surgery.

Excessive intravenous calorie intakes have been shown to increase fat deposition and CO2 production with deleterious results. A controlled trial has therefore been performed to determine whether there is clinical benefit from tailoring calorie intake of intravenously fed patients to the patient's metabolic expenditure. Twenty patients requiring intravenous feeding after abdominal surgery were randomly allocated to receive either (i) a constant regimen containing 2 600 calories and 15.55 g nitrogen or (ii) a varied regimen with a fixed calorie: N2 ratio of 167:1 but with the calorie intake adjusted according to the previous day's metabolic expenditure. Only one patient had a requirement of greater than 2 600 calories; there was no difference in mean RQ during intravenous feeding between the constant regimen (0.90 +/- 0.10 s.d.) and the varied regimen (0.90 +/- 0.09 s.d.) and no significant difference in peak CO2 production. Excess calorie intake over expenditure did not correlate with increased positive nitrogen balance but on the varied regimen patients receiving a higher nitrogen intake tended to be in more positive nitrogen balance. This study suggests that a fixed calorie intake of 2 600 calories per day is suitable for adult patients requiring intravenous feeding after abdominal surgery but currently prescribed nitrogen intakes may be suboptimal.

Journal Article↗
PubMed1985

A new method for measuring unidirectional transplacental flux.

A new method for measuring unidirectional transplacental flux has been developed. Unlike indicator-dilution techniques, it does not depend on the use of a second reference tracer to study the substance of interest, nor on assumptions that the placenta can be modelled as a series of long, parallel, tubular capillaries. The only assumptions required are that the placenta behaves as a linear, time-invariant system and does not distinguish between tracer and tracee. The method was validated by measuring unidirectional flux rates of Evans Blue dye in an hydraulic model in which the true flux rates were controlled by peristaltic pumps. There was excellent agreement between the calculated and true flux rates. A preliminary experiment was carried out in vitro using a dually perfused human placenta to measure the unidirectional flux rates of L-lactate. At a steady state lactate concentration of 25.5 mM, maternal to foetal flux rate was 30.1 mumol min-1 and foetal to maternal flux rate was 34.0 mumol min-1, in agreement with measurements reported by other workers.

Female↗
PubMed1985

Splenectomy does not cure the thrombocytopenia of systemic lupus erythematosus.

Fourteen patients with systemic lupus erythematosus had splenectomies done between 1960 and 1982 for treatment of severe thrombocytopenia. Thrombocytopenia persisted or recurred within 1 month postoperatively in five patients and within 6 months in three others. Three patients had late recurrence (18, 30, and 54 months after splenectomy); in two it was probably related to withdrawal of immunosuppressive agents or corticosteroids. Median lowest platelet count before splenectomy and median platelet count at relapse or failure of splenectomy were both 8000/microL. Only two patients maintained normal platelet counts without need for corticosteroids or other treatment. These results differ from those in patients with idiopathic thrombocytopenic purpura. Other treatments should be tried before splenectomy is done for thrombocytopenia in patients with systemic lupus erythematosus.

Adult↗
PubMed1985

Lumbar spinal stenosis. Clinical features, diagnostic procedures, and results of surgical treatment in 68 patients.

Our experience with 68 patients with strictly defined, myelographically proven, surgically confirmed lumbar spinal stenosis seen over a 30-month period was reviewed. Pseudoclaudication was the commonest symptom (94%) and was described by patients as pain (93%), numbness (63%), or weakness (43%). Symptoms were frequently bilateral (68%) and generally relieved by flexing the lumbosacral spine. Neurologic abnormalities were found in a minority of patients and were usually mild. Electromyography showed one or more lumbosacral radiculopathies in 34 of 37 patients examined. Radiographic evidence of degenerative disk or joint disease was found in 63 patients. All patients had stenosis on myelography, with narrowing at L2, L3, and L4 being the commonest; 30% had multi-level stenosis. Two of ten computed tomograms were normal. Surgery was extensive; 72% of patients had three or more laminae removed. At a mean of 4 years after surgery, 84% of patients reported that surgery had yielded good to excellent results.

Adult↗
PubMed1985

Takayasu arteritis. A study of 32 North American patients.

Thirty-two patients (26 female, 6 male) with angiographically diagnosed Takayasu arteritis were seen at the Mayo Clinic between 1971 and 1982. Racial composition of this group was 23 North American Caucasians, 4 Mexicans, 3 Orientals, 1 Native American, and 1 patient of Middle Eastern origin. Incidence of the disease in Olmsted County, Minnesota, was 2.6/million/year. Diagnosis was often delayed for long periods of time, with a median delay of 18 months. Patients had both non-vascular symptoms (arthralgias in 56%, fever in 44%, weight loss in 38%) and symptoms of vascular stenosis such as arm claudication (47%) and hypertension due to renal artery stenosis (41%). All patients had either multiple vascular bruits (94%) or absent pulses (50%). Laboratory findings included anemia (44%) and elevations of erythrocyte sedimentation rate (78%). Almost all patients had multiple sites of arterial involvement documented by angiogram with various combinations of stenosis, luminal irregularity and aneurysm formation. Response to corticosteroid treatment was usually very good, with dramatic improvement in non-vascular symptoms and return of pulses in 8 of the 16 patients with absent pulses prior to treatment. Five-year survival rate from time of diagnosis was 94%. Twelve patients underwent surgical procedures involving the carotid arteries (5 cases), subclavian artery (4 cases) and renal arteries (3 cases). Three aneurysms were resected, one had aortic valve replacement for severe aortic regurgitation, and two patients underwent transluminal angioplasty. Pathologic changes were restricted to the media and adventitial layers of the vessel wall and were indistinguishable from those of giant-cell or temporal arteritis. Takayasu arteritis is more common than previously suspected in North America, is not restricted to any one racial group, and is readily treatable with corticosteroids and surgical vascular reconstruction.

Adolescent↗
PubMed1985

An epidemiological view of poisoning.

An epidemiological approach to understanding the incidence and control of injuries is essential. Epidemiology facilitates discovery of factors contributing to the occurrence of, in this case, injuries from poisoning. This page reviews those theories relative to agent, host and environment involved in an unintentional poisoning incident. It is through an understanding of each of these factors that the poisoning incident becomes more clearly defined.

Adolescent↗
PubMed1985

Influence of fraction unbound upon the renal clearance of furosemide in the isolated perfused rat kidney.

The influence of fraction furosemide unbound (varied over a 28-fold range) upon its renal clearance was studied in an isolated perfused rat kidney, while renal function was maintained. Renal clearance and unbound fraction of furosemide were found to be related linearly, the average unbound renal clearance being 3.3 ml min-1. Urine pH and urine flow rate did not influence furosemide renal clearance in the ranges experienced in this study. Our results are consistent with those predicted from a consideration of the kinetics of renal excretion.

Albumins↗