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Biomedical subjects

S L Williams

Publications and source records attributed to S L Williams.

At least 19 recordsLinked to original sources
PubMed1992

Prior exposure to a running wheel and scheduled food attenuates polydipsia acquisition.

Groups of rats were given different histories before exposure to daily, 2-h fixed-interval (FI) 1-min food-schedule sessions with water available. In a previous study, a group with a history of chronic exposure to FI 1-min sessions without water subsequently had a reduced rate of acquisition and final level of schedule-induced polydipsia compared to a control group lacking this history. In the present study, groups with histories of chronic exposure to FI 1-min sessions and a concurrent running wheel were even more attenuated in their subsequent acquisition of polydipsia. Substitution of 5% ethanol for session water in the final phase produced a convergence in group intakes, except for a group which continued to have access to the running wheel. The ethanol intake of this group was relatively suppressed.

Animals↗
PubMed1991

Effectiveness and tolerance of long-term malaria prophylaxis with mefloquine. Need for a better dosing regimen.

To measure the effectiveness and tolerance of long-term malaria prophylaxis with mefloquine, the incidence of Plasmodium falciparum malaria and of adverse reactions was compared in Peace Corps volunteers in West Africa who took mefloquine every 2 weeks and in volunteers who took chloroquine phosphate weekly. Mefloquine was only 63% more effective than chloroquine; the monthly incidence of P falciparum infections was one case per 100 volunteers who took mefloquine and 2.7 cases per 100 volunteers who took chloroquine. Using daily proguanil (chloroguanide) hydrochloride in addition to chloroquine did not provide additional protection. All mefloquine prophylaxis failures occurred during the second week of the every-2-weeks dosing regimen in volunteers who had used mefloquine for more than 2 months. Blood concentrations of mefloquine were lower during the second week of the alternate-week regimen than during the first week, suggesting that blood levels are too low during the second week to suppress parasitemia. No serious adverse reactions were observed. The results indicate that a dosing regimen of 250 mg of mefloquine weekly should be considered for travelers to areas with chloroquine-resistant P falciparum malaria.

Adult↗
PubMed1991

Cervical cancer metastatic to the breast: a rare presentation of tumor dissemination.

Metastatic disease presenting in the mammary gland from gynecologic malignancies is a rare occurrence. A case of metastatic adenosquamous carcinoma of the cervix presenting as an inflammatory breast lesion is reported. Metastases within the breast have distinct clinical, radiographic, and histologic features and should be suspected in a patient with a breast mass and a known extramammary primary. As with other distant metastases of cervical cancer, mammary gland involvement portends a poor prognosis.

Adult↗
PubMed1991

The effect of cataract severity and morphology on the reliability of the Lens Opacities Classification System II (LOCS II).

Data collected from 3646 eyes in the Italian-American Natural History Study of Age-Related Cataract were used to investigate whether the reliability of the Lens Opacities Classification System II (LOCS II) by the severity of the opacity that is being graded or is influenced by the presence and severity of coexisting opacities. Reliability was assessed by comparing the slit-lamp gradings of two clinical examiners (346 eyes) and the gradings performed at the slit lamp with gradings of photographs (3646 eyes). The severity of cortical and nuclear opacities did not affect the reproducibility of slit-lamp gradings, but clinical grading of posterior subcapsular opacities became more reliable as the severity of the posterior subcapsular opacities increased. More advanced coexisting opacities decreased the agreement in the slit-lamp diagnosis of nuclear, but not cortical or posterior subcapsular, opacities. Comparisons of clinical and photographic gradings showed very good to excellent agreement for nuclear and cortical opacities, regardless of the severity of the specific opacity or the severity of the coexisting opacities. Agreement in diagnosing posterior subcapsular opacities was decreased in eyes with milder posterior subcapsular opacities and in eyes with more severe coexisting nuclear and/or cortical opacities. The effect of the severity of the opacity being graded and the severity of coexisting opacities on the reliability of the LOCS II must be considered in studies that use the system to classify and grade cataracts.

Aged↗
PubMed1990

Trends in prescribing of antihypertensive drugs in Australia, 1977-1987.

Prescribing of hypotensive agents, beta-blockers and diuretics was analysed using data from the Pharmaceutical Benefits Scheme, adjusted to reflect prescribing for hypertension, over 1977-1987. Prescribing of these three drug groups combined increased by approximately 50% over the period. Notable trends were decreased prescribing of bendrofluazide, chlorothiazide and methyldopa and increased prescribing of hydrochlorothiazide with amiloride, atenolol, metoprolol and prazosin, and, most recently, captopril and enalapril. The increase in prescribing of drugs for hypertension, combined with the choice of more expensive drugs, has resulted in a substantial increase in the drug costs associated with treating hypertension.

Adrenergic beta-Antagonists↗
PubMed1990

Effect of temperature on myosin phosphorylation in mouse skeletal muscle.

The effect of muscle contraction on phosphorylatable myosin light chain (P-light chain) phosphate content and isometric twitch tension was examined at 25, 30, and 35 degrees C in intact mouse extensor digitorum longus muscle. Peak tetanic tension was unaffected by temperature, whereas peak unpotentiated isometric twitch tension was inversely proportional to muscle incubation temperature. The extent of phosphate incorporation into P-light chain elicited by a 20-s train of twitches (5/s) was inversely proportional to muscle incubation temperature, whereas the fractional increase in twitch tension (twitch potentiation) elicited by repetitive stimulation was directly proportional to muscle incubation temperature. After the twitch train, the rate of decline of potentiated twitch tension and of P-light chain dephosphorylation was directly proportional to muscle incubation temperature. The net result was that a significant and unique relationship between P-light chain phosphate content and contraction-induced tension potentiation existed at each temperature examined. The slope of the P-light chain phosphate vs. isometric twitch potentiation relationship varied directly as a function of muscle incubation temperature. The observations that the slope of this relationship increases and that unpotentiated twitch tension decreases when muscle incubation temperature is increased support the hypothesis that contraction-induced tension potentiation in intact mammalian skeletal muscle is the result of a sensitization of the contractile element to activation by Ca2+ that is brought about by P-light chain phosphorylation.

Animals↗
PubMed1989

Guided mastery and stimulus exposure treatments for severe performance anxiety in agoraphobics.

The present experiment compared two models of treatment for high performance-related anxiety in agoraphobics: the stimulus exposure model, which emphasizes extinguishing anxiety by promoting prolonged exposure to phobic stimuli, and the self-efficacy model, which emphasizes building a sense of mastery by promoting rapid proficient performance accomplishments. Subjects were 26 agoraphobics who could perform phobic activities when behaviorally tested, but who became highly anxious when doing so. Subjects were assigned at random to either (a) guided mastery treatment based on self-efficacy theory, (b) stimulus exposure treatment, or (c) delayed treatment. The results showed that guided mastery was significantly more effective than stimulus exposure in reducing performance anxiety, and this difference increased over the follow-up period. The findings indicate that therapists can implement performance-based treatment more effectively by assisting clients to achieve proficient performance than by simply encouraging them to expose themselves to phobic stimuli.

Adult↗
PubMed1989

Generalization of therapeutic changes in agoraphobia: the role of perceived self-efficacy.

Investigated the extent and mechanisms of therapeutic generalization across distinct areas of agoraphobic dysfunction. Twenty-seven severe agoraphobics were each given performance-based treatment for some phobic areas while leaving their other phobias untreated. Behavioral tests revealed that (a) the treated phobias improved significantly more than the untreated (transfer) phobias, (b) the transfer phobias improved significantly more than control phobias, and (c) the transfer benefits were highly variable within and between subjects. Analyses of possible cognitive mechanisms revealed that perceived self-efficacy accurately predicted treatment and transfer effects even when alternative factors such as previous behavior, anticipated anxiety, anticipated panic, perceived danger, and subjective anxiety were held constant. In contrast, these alternative factors lost most or all predictive value when self-efficacy was held constant. Agoraphobia thus appears to be neither a unitary entity nor a mere collection of independent phobias, but a complexly patterned problem governed largely by self-perceptions of coping efficacy.

Adult↗
PubMed1989

The Bay Area Functional Performance Evaluation: development and standardization.

The Bay Area Functional Performance Evaluation (BaFPE) was developed in 1977-1978 to meet the need for a reliable and valid instrument for assessing the general functional performance of patients treated in psychiatric occupational therapy. It consists of two subtests, the Task-Oriented Assessment and the Social Interaction Scale. These subtests evaluate two aspects of general functional performance--task-oriented and social behavior--that are important in assessing clients with emotional, cognitive, or behavioral deficits. This article traces the instrument's standardization over a 10-year period of development and includes a discussion of its theoretical premises, its content, and the revisions to date. Research on the reliability and validity of the BaFPE is summarized.

Humans↗
PubMed1988

Prior schedule exposure reduces the acquisition of schedule-induced polydipsia.

Two groups of rats were given different initial histories before exposing them to daily, 2-hr fixed-interval 1-min (FI 1-min) food-pellet sessions with water freely available. For the initial-history phase (approximately 17 weeks), a Schedule-History Group had no water available during FI 1-min sessions, while a Home-Cage-History Group was maintained at the same body weight (80% of free feeding) in home cages. When water then became available for both groups during FI 1-min sessions, the Schedule-History Group was retarded in their rate of acquisition and final level of schedule-induced polydipsia relative to the Home-Cage-History Group. Substitution of 5% ethanol solution for session water in the final phase produced a like intake level for both groups typical for these inducing conditions. It was concluded that the probability of drinking water in a session situation is reduced by a lengthy history of water unavailability, thereby attenuating the acquisition rate and final level of schedule-induced water overdrinking.

Alcohol Drinking↗
PubMed1986

Long-term renal function in kidney donors: a comparison of donors and their siblings.

To assess the effects of unilateral nephrectomy, we evaluated renal function and hypertension in kidney donors who had had nephrectomies 10 years ago or more and siblings who had not had nephrectomies. No statistically significant difference was found between the prevalence of hypertension in donors and siblings. Serum creatinine concentrations were 20% higher in donors and creatinine clearances, 20% lower than corresponding values in siblings. Twenty-four-hour urinary protein excretion increased in all donors after nephrectomy and was more marked in men than women. Of the 38 donors, 12 excreted more than 150 mg/24 h of urinary protein, but only 2 excreted more than 300 mg/24 h. The presence of proteinuria did not correlate with the presence of hypertension, level of renal function, or time since nephrectomy. We conclude that, with the exception of mild proteinuria of unknown clinical significance, unilateral nephrectomy is not associated with adverse effects on kidney function.

Adult↗
PubMed1985

Internal oblique muscle pedicle flap for coverage of a major soft tissue defect of the groin.

We describe a new muscle flap, using the internal oblique muscle as a transposition flap based on the ascending branch of the deep circumflex iliac artery, for coverage of a groin defect with exposed femoral vessels. This muscle also has potential usefulness as a pedicle flap for coverage of the anterior perineum and midline lower abdominal defects. It is a thin, flat muscle with excellent vascularity and is safe and reliable to use. The donor site scar is well concealed. The disadvantages are a possibly bloody and tedious dissection, and the long-term potential for abdominal wall weakness or herniation. In the case reported, no abdominal wall laxity or herniation were noted at eight and one-half months. We believe that the internal oblique muscle flap is a useful technique that complements the already popular methods of reconstruction for groin defects.

Abdominal Muscles↗