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Biomedical subjects

S L Williams

Publications and source records attributed to S L Williams.

At least 37 records · Page 2Linked to original sources
PubMed1994

Tension transduction device for functional evaluation of the rat peroneal nerve.

Current techniques for evaluating animal model nerve regeneration lack accurate, sensitive and reproducible methods to determine neuromuscular function. We have developed a tension transduction apparatus which measures the magnitude of ankle dorsiflexion produced by normal rats during bipolar stimulation of the surgically exposed peroneal nerve. Three groups of animals were used to evaluate the consistency and overall reliability of this apparatus. Within the first group of 4 animals, we determined variability in a single testing period of 8 successive stimulations. The mean normalized standard deviation of dorsiflexion tension produced was 2.9% of the mean. In the second group, comparison of right and left dorsiflexion tension in 8 animals showed a difference of less than 2% (right: 134.2 g; left: 131.6 g), demonstrating that one lower limb can be used as a control for the contralateral limb. In the third group, 12 animals were tested on two separate occasions, 2 months apart, tension production increased 10% (from 122 to 134 g) and corresponded with an average weight increase, per animal, of 100 g (30%) during the 2-month rest period. Despite the increase in weight and strength, the initial procedure had a negative effect upon the maximum tension produced compared to a previously unoperated leg (prior operation: 134 g; no prior operation: 144 g). The reproducibility of data obtainable with this new device allows for its incorporation in future studies, as well as the correlation of such functional data with other current methods of studying nerve regeneration.

Animals↗
PubMed1994

Two-staged breast reconstruction in patients with symptomatic macromastia requiring mastectomy.

Patients with symptomatic macromastia undergoing mastectomy for the treatment of malignant breast disease are candidates for a two-staged operation resulting in breast reconstruction and contralateral breast reduction. Five patients with symptomatic macromastia underwent a skin-sparing mastectomy for breast disease using a modified Wise incision. The first stage of the breast reconstruction was performed with a de-epithelialized transverse rectus abdominis musculocutaneous (TRAM) flap. Second-stage breast reconstruction was conducted 4 to 6 months later when revision of the TRAM reconstructed breast and concurrent contralateral breast reduction were performed with the intent of tailoring the reduced breast to approximate the revised TRAM breast mound. Excess areola from the reduced breast was harvested and used as a full-thickness graft to reconstruct the TRAM areola complex. Patients followed for 5 to 30 months postoperatively confirm resolution of macromastia symptoms, correction of the mastectomy defect, and symmetrical breast mound creation in a timely two-staged procedure. The two-staged breast reconstruction described represents an expedient plan for patients with symptomatic macromastia requiring mastectomy for breast disease. Skin-sparing mastectomy, modified Wise pattern incisions, utilization of usually discarded areola tissue, and creation of symmetrical breast mounds during the second stage of the reconstruction highlight the salient features of this patient management paradigm.

Adult↗
PubMed1993

Partial mastectomy and breast reduction as a valuable treatment option for patients with macromastia and carcinoma of the breast.

The essential goals of every reconstructive procedure of the breast are to create a breast mound and establish symmetry. Breast conservation operation is now a widely accepted treatment for carcinoma of the breast. Four patients who presented with macromastia or mammary hypertrophy and a simultaneous carcinoma of the breast were treated by combined partial mastectomy and bilateral breast reduction. Incisions on the breast were made using standard Wise pattern (keyhole) markings. In each instance, the tumor was removed with a generous margin of normal surrounding mammary tissue. Two procedures used the inferior pedicle technique and two were done by resection and transplantation of the nipple. The average mammary tissue resection was 825 grams. All incisions healed primarily and necessary adjuvant chemoradiation was not delayed. Each patient is alive and well without evidence of disease with a follow-up period ranging from seven to 43 months. Postoperatively, the appearance of the breast is esthetically improved and all symptoms related to macromastia have resolved. Advantages of combining these two techniques include improved symmetry, easier postoperative self-examination of the breast and decreased radiation effect noted with larger breasts. Postoperative mammograms have been useful for patient follow-up evaluation. Combined segmental mastectomy and breast reduction represents a valuable treatment option for the patient who presents with macromastia and carcinoma of the breast. The carcinoma ablative procedure is not compromised and the improved symmetry of the breast has resulted in an excellent cosmetic outcome in these patients.

Adult↗
PubMed1993

Language comprehension in ape and child.

Previous investigations of the linguistic capacities of apes have focused on the ape's ability to produce words, and there has been little concern for comprehension. By contrast, it is increasingly recognized that comprehension precedes production in the language development of normal human children, and it may indeed guide production. It has been demonstrated that some species can process speech sounds categorically in a manner similar to that observed in humans. Consequently, it should be possible for such species to comprehend language if they have the cognitive capacity to understand word-referent relations and syntactic structure. Popular theories of human language acquisition suggest that the ability to process syntactic information is unique to humans and reflects a novel biological adaptation not seen in other animals. The current report addresses this issue through systematic experimental comparisons of the language comprehension skills of a 2-year-old child and an 8 year-old bonobo (Pan paniscus) who was raised in a language environment similar to that in which children are raised but specifically modified to be appropriate for an ape. Both subjects (child and bonobo) were exposed to spoken English and lexigrams from infancy, and neither was trained to comprehend speech. A common caretaker participated in the rearing of both subjects. All language acquisition was through observational learning. Without prior training, subjects were asked to respond to the same 660 novel sentences. All responses were videotaped and scored for accuracy of comprehension of the English language. The results indicated that both subjects comprehended novel requests and simple syntactic devices. The bonobo decoded the syntactic device of word recursion with higher accuracy than the child; however, the child tended to do better than the bonobo on the conjunctive, a structure that places a greater burden on short-term memory. Both subjects performed as well on sentences that required the ability to reverse work order as they did on sentences that did not require this capacity. These results are discussed in light of a model of the evolution of language that suggests that the potential for language comprehension preceded the appearance of speech by several million years at minimum. The onset of speech is linked to the appearance of fully adapted bipedalism, which necessitated reorientation of the laryngeal tract and made closure of the soft palate possible. For the first time, such closure permitted mammals to easily produce sounds that could be interpreted by the mammalian auditory system in a categorical manner. When these sounds were paired with the previously extant capacity to produce vowels, it became possible to form "bounded vowels" or sound units that could readily be discriminated as units by the auditory system. It is suggested that this physical adaptation allowed the extant cognitive capacity of the hominids to embark on a speech-like mode of communication.

Animals↗
PubMed1993

The pediatric patient in the post anesthesia care unit.

This article provides an overview of pediatric post anesthesia care. It highlights important aspects of care that are frequently encountered in practice or have the potential for being problematic. These include airway management, fluid maintenance, the treatment of seizures, thermoregulation, the management of malignant hyperthermia, the identification and treatment of emergence delirium, and the availability of appropriate emergency equipment and medications.

Child↗
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↗