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Biomedical subjects

A Powell

Publications and source records attributed to A Powell.

At least 55 records · Page 3Linked to original sources
PubMed1994

Surgical voice restoration: the Sunderland experience.

Surgical voice restoration following tracheo-oesophageal puncture is a well established procedure and the principal means of speech rehabilitation following laryngectomy and more recently laryngopharyngectomy. A valve prosthesis was used in 65 patients, 50 of whom underwent insertion at the time of surgery. Of the 65, 49 were men, 16 women and 15 have since died; the median length of follow-up of valves in situ has been 24.7 months (range 2-46 months). Of the 50 living patients 80% were using the valve at last examination. Complications arose in 52% but were generally minor and easily overcome.

Adult↗
PubMed1993

Efficacy of a tiered therapy defibrillator system used to treat recurrent ventricular arrhythmias refractory to drugs.

OBJECTIVE: To evaluate an implantable tiered therapy defibrillator system that delivered antitachycardia pacing treatment for slower well tolerated ventricular tachycardias and cardioversion or defibrillation for fast tachycardias or ventricular fibrillation. METHODS: A tiered treatment device (Ventritex Cadence V-100) was implanted in 30 patients with ventricular tachycardia that was refractory to drugs. Efficacy was evaluated by the responses of induced or spontaneous arrhythmias to the treatments delivered. RESULTS: Antitachycardia pacing successfully terminated 80% of episodes of ventricular tachycardia induced by non-invasive programmed stimulation, but acceleration was brought about by pacing in six patients in 10% of episodes. During a follow up of two to 17 (mean seven) months, 18 patients (60%) had recurrence of ventricular arrhythmias. Antitachycardia pacing terminated ventricular tachycardia in 17 of 18 patients in 87% of episodes. Twelve patients received shocks for ventricular tachycardia or fibrillation. Failure of pacing, with subsequent cardioversion, occurred in nine patients (50%) in one or more episodes. Acceleration of tachycardia by pacing occurred in 10 patients in 5% of episodes. Only two of these patients had experienced acceleration of previously induced arrhythmia. Five patients had spontaneous fast ventricular tachycardia or fibrillation treated by cardioversion or defibrillation. Spurious treatment was delivered in nine patients (30%), during atrial fibrillation in five, sinus tachycardia in two, and because of fracture of the sensing lead system in two patients. The retrieval of stored intracardiac electrograms was of clinical value in assessing spurious treatment. CONCLUSIONS: Tiered treatment was effective in terminating recurrent ventricular arrhythmias in these selected patients. Most episodes were treated successfully by pacing, and resistant tachycardias, pacing induced acceleration, or haemodynamically compromising arrhythmias were treated by shocks.

Adolescent↗
PubMed1991

Biochemical and physiological characterization of the efrotomycin fermentation.

An efrotomycin fermentation was characterized through physical, chemical and biochemical studies. Growth of the actinomycete, Nocardia lactamdurans occurred during the first 50 h of the fermentation cycle at the expense of glucose, protein, and triglycerides. The initiation of efrotomycin biosynthesis was observed when glucose dropped to a low concentration. Upon glucose depletion, cell growth ceased and a switch in the respiratory quotient occurred. Efrotomycin biosynthesis was supported by the utilization of soybean oil and starch. Analysis of triglyceride metabolism showed that no diglycerides or monoglycerides accumulated during the fermentation. The activity of extracellular enzymes (lipase, protease, and amylase) increased during the cell growth phase and decreased significantly after 150 h. The concentrations of DNA, tetrahydro-vitamin K2 (a membrane component), and free amino acids in the supernatant increased dramatically late in the fermentation cycle (225 h), indicating massive cell lysis. During this same time period, a reduction in cellular respiratory activity and efrotomycin biosynthesis were observed.

Amino Acids↗
PubMed1990

Is group psychotherapy feasible for oncology outpatients attenders selected on the basis of psychological morbidity?

Of 120 consecutive attenders at an oncology outpatients department, 108 were screened for psychological symptoms using the Hospital Anxiety and Depression Scale (Zigmond & Snaith, 1983). Thirty-nine patients had significant scores indicating moderate anxiety and/or depression. We felt that this warranted an offer of group psychotherapy in the belief that sharing issues and exploring personal concerns may alleviate some of the experienced psychological distress. Only 10 patients consented to and were able to attend this group, with which five patients persisted. Thus in this group of patients with advanced cancer group psychotherapy was applicable only to a limited number of selected patients. The nature of this study and the size of the population markedly limited our ability to comment on the usefulness of group psychotherapy. Many patients, particularly the most severely psychologically distressed, continued to require other forms of support, particularly domiciliary individual therapy.

Aged↗
PubMed1990

The five year school medical--time for change.

School medical records of 1000 children born in 1981 were studied retrospectively. They showed that once known medical problems and those screened for by the school nurse (hearing, vision, growth) were excluded, only 17 problems requiring treatment were discovered: speech (n = 10), development (n = 3), undescended testes (n = 3), and phimosis (n = 1). This indicates that routine screening by a nurse, backed up by selective medical examination by the school doctor, is efficient and effective.

Child, Preschool↗
PubMed1990

Dyskinetic movements, cognitive impairment, and negative symptoms in elderly neuropsychiatric patients.

The presence or absence of tardive dyskinesia, cognitive status, and psychopathology were assessed in a group of elderly male psychiatric patients (N = 49) in a nursing home setting. Twenty-five patients were found to have tardive dyskinesia, which was associated with a greater degree of cognitive impairment and negative symptoms. This finding was not related to obvious macroscopic organic pathologies, which were less prevalent in the dyskinetic patients. In fact, patients with frontal lesions (primarily lobotomies) had a significantly lower prevalence of tardive dyskinesia.

Aged↗
PubMed1989

Infundibular metastasis and panhypopituitarism.

A patient with no known history of primary neoplasia presented with panhypopituitarism secondary to metastasis. Complete anterior pituitary failure was documented by pituitary reserve testing. However, at autopsy there was extensive carcinomatous invasion of the hypothalamus and infundibulum but no adenohypophyseal involvement. The possibility of metastatic disease should be considered in patients presenting with panhypopituitarism. The literature covering this topic is reviewed.

Carcinoma, Small Cell↗
PubMed1988

Dissecting aneurysm of a right-sided descending aorta with a left-sided aortic arch.

A 66-year-old man presented with myocardial infarction. Chest X-ray showed a large mediastinal mass. Aortic dissection was suggested by a past history of chest trauma, but the mass was in a very atypical site. Dissection of an abnormally placed right-sided descending aorta was confirmed by computed tomography. The aortic arch lay on the left side. This rare combination of congenital and acquired heart disease led to diagnostic difficulty.

Aged↗
PubMed1987

Mineral balances of men and women consuming high fiber diets with complex or simple carbohydrate.

Calcium, copper, iron, magnesium, manganese, and zinc balances of 20 men, 19 premenopausal women, and 12 postmenopausal women were determined while they consumed self-selected diets or high fiber diets with either complex or simple carbohydrate. Self-selected intakes of calcium, magnesium, copper and zinc were generally below RDA levels. Iron intakes of premenopausal women were less than two-thirds RDA. Balances during the self-selected intake period of calcium in men and women and of magnesium and zinc in women were negative, but lower-than-usual intakes could have contributed to this. High fiber diets did not adversely affect zinc, copper, manganese or iron balances. Calcium and magnesium balances were generally negative, especially in women, even though intakes were adequate. Excretion of copper was increased in premenopausal women consuming the simple carbohydrate diet. The levels of magnesium and especially calcium needed to maintain balance when consuming a high fiber diet may be above present RDA levels.

Adult↗
PubMed1987

What motivates medical students: how they see themselves and their profession.

This paper describes a repertory grid study of medical students' perceptions of medicine and its specialties. By sampling student attitudes at different stages of training, the authors show that in this sample, final-year medical students have a more vocational out-look than first-year students, in whom concern with relief of suffering is more important than aiming at cure and in whom materialistic success matters less than doing something 'important for mankind.' This is reflected in a shift of interest away from the surgical specialties.

Aspirations, Psychological↗
PubMed1986

Effects of sugars on indices of glucose tolerance in humans.

Ten men and nine women were studied to determine whether replacement of utilizable complex carbohydrate by sugars (mono- and disaccharides) in a high-fiber, low-saturated fat diet would affect indices of glucose tolerance. Diets differed in that the 50% of calories derived from carbohydrate was either 35% complex and 15% sugars (low-sugar) on 15% complex and 35% sugars (high-sugar). Summation of glucose responses 30-180 min following an oral glucose tolerance test was significantly higher in men, but not women, after they consumed the high-sugar diet. Corresponding insulin responses were significantly higher in men consuming the high-sugar compared to the low-sugar diet. Insulin binding was significantly lower during the base line period and after the high-sugar diet compared to the low-sugar diet. Results indicate that sugars adversely affect indices of glucose tolerance when they replace complex carbohydrates even in a high-fiber, low-saturated fat diet.

Adult↗
PubMed1986

Adrenergic receptors in human liver plasma membranes: predominance of beta 2- and alpha 1-receptor subtypes.

Adrenergic receptors in human liver plasma membranes were characterized by radioligand binding assays. The binding of [3H]dihydroalprenolol [( 3H]DHA) to partially purified membranes was rapid, of high affinity, saturable, and stereospecific. The binding of [125I]iodocyanopindolol to the same membranes was also saturable and stereospecific, but extremely slow, and at 37 C required about 6 h for equilibration. The maximum number of binding sites from six livers determined with these two beta-receptor ligands was 36-83 fmol/mg protein. Catecholaminergic agonists competed for these binding sites in the order typical for beta 2-adrenergic receptors. IPS 339 [(tertiarybutylamino-3-ol-2-propyl)oximino-9-fluorene hydrochloride], a beta 2-selective antagonist, was at least 3 orders of magnitude more potent in inhibiting the binding of [3H]DHA than the beta 1-antagonist, atenolol. Computer-aided analysis of the competition curves as well as Hofstee transformations of the binding data indicated the predominance of the beta 2-subtype. The GTP analog guanyl-5'-yl-imidodiphosphate, decreased the binding affinity of the agonist, l-isoproterenol, indicating the modulation of agonist-promoted coupling of the receptors to guanine nucleotide regulatory proteins. The maximum number of binding sites for the binding of [3H]prazosin and [3H]dihydroergocryptine were the same (60-70 fmol/mg protein), indicating that the majority of the alpha-receptors are of the alpha 1-subtype. Competition experiments with prazosin and yohimbine confirmed the predominance of the alpha 1-receptor subtype, although the presence of alpha 2-receptors cannot be completely ruled out. These results indicate that adrenergic receptors in human liver plasma membranes are predominantly of the beta 2- and alpha 1-subtypes.

Aged↗
PubMed1985

Bone grafting: role of histocompatibility in transplantation.

The role of histocompatibility matching in bone allografting was studied in two canine bone graft models. In a cancellous ulnar segmental replacement model, frozen bone allografts exchanged between closely matched dogs were significantly better incorporated by radiographic and histologic criteria than were strongly incompatible grafts. Frozen allografts from disparate donors in recipients receiving immunosuppression appeared indistinguishable 6 months later from those in the untreated closely matched groups and from fresh autografts. Fresh vascularized orthotopically placed fibular bone grafts were evaluated by quantitative blood flow assessment, microangiography, and fluorochrome histomorphometry. Revascularized grafts exchanged between untreated closely matched dogs demonstrated preservation of blood flow and a pattern of repair that was delayed but not otherwise different than vascularized autografts. These results suggest that fresh vascularized grafts in the judiciously matched or immunosuppressed recipient offer attractive clinical possibilities.

Animals↗
PubMed1985

Relationship of maternal behavioral style to the development of organically impaired mentally retarded infants.

The relationship of maternal behavioral style to the cognitive developmental status of 60, 1-, 2-, and 3-year-old organically impaired, mentally retarded children was investigated. Eighteen global maternal behaviors and four child behaviors were rated on a 10-minute video tape of mother-child play. A factor analysis of the maternal behavioral items revealed three major parameters of behavior. Child-Oriented/Maternal Pleasure was related positively, whereas Quantity of Stimulation and Control were related negatively to Children's Bayley Mental Development scores. Maternal behavioral style was not related to either the ratings of the children's behavior or to the children's current health status and family SES, but was related to the amount of time children had been in intervention programs. Findings were discussed in terms of their implications for intervention with mothers and their retarded infants.

Age Factors↗