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Biomedical subjects

S Smith

Publications and source records attributed to S Smith.

At least 415 records · Page 23Linked to original sources
PubMed1996

Mobilizing positive reinforcement in communities to reduce youth access to tobacco.

A community intervention to mobilize positive reinforcement for not selling tobacco to young people was evaluated. The intervention had five components: (a) mobilization of community support, (b) merchant education, (c) changing consequences to clerks for selling or not selling to those under 18, (d) publicity about clerks' refusals to sell, and (e) feedback to store owners or managers about the extent of their sales to adolescents. A multiple baseline design experiment was conducted, in which two small Oregon communities received the intervention, while two other continued in baseline. Outlets' willingness to sell was assessed repeatedly by teenage volunteers. The intervention significantly reduced the proportion of stores willing to sell. Mobilizing social and material reinforcement for stores not selling tobacco to young people is a viable means of reducing such sales. It may be especially valuable in communities where laws against sales to minors go unenforced.

Adolescent↗
PubMed1996

Experimental evaluation of a modular approach to mobilizing antitobacco influences of peers and parents.

The experimental evaluation of two components of a community intervention to prevent adolescent tobacco use are described. Youth antitobacco activities (e.g., peer quizzes, sidewalk art, poster and T-shirt giveaways, etc.) and family communications activities (pamphlets to parents and student quizzes of parents) were evaluated in two time-series experiments, each of which was conducted in two experimental and one control community. Students in Grades 6 and 8 and their parents were assessed in a series of four phone surveys in the first experiment and six phone surveys in the second. Implementation of the youth antitobacco and family communications activities led to significantly greater exposure of young people to antitobacco information. They led to increases in parent and youth knowledge about tobacco use and more negative attitudes toward tobacco. In Experiment 2, youths in intervention communities had significantly lower rated intentions to smoke. The findings suggest the value of a modular approach to community interventions for influencing the social context relevant to the onset of adolescent tobacco use.

Adolescent↗
PubMed1996

Cardiac transplantation after mechanical circulatory support: a Canadian perspective.

BACKGROUND: To assess the relative efficacy of cardiac transplantation after mechanical circulatory support with a variety of support systems, we analyzed our consecutive series of patients who had and did not have mechanical support before transplantation. METHODS: A review of 209 patients undergoing cardiac transplantation from 1984 to May 1995 was performed. Group 1 consisted of 110 patients who were maintained on oral medications while awaiting transplantation, and group 2 consisted of 60 patients who required intravenous inotropic support. Group 3 included 39 patients who had transplantation after mechanical circulatory support for cardiogenic shock. The indication for device implantation was acute onset of cardiogenic shock in 38 patients and deterioration while awaiting transplantation in 1 patient. The support systems were an intraaortic balloon pump in 13 (subgroup 3A), a ventricular assist device in 7 (subgroup 3B), and a total artificial heart in 19 patients (subgroup 3C). RESULTS: After transplantation, infection was more common in group 3 (56%) than in group 1 (28%) or group 2 (32%) (p = 0.005). Survival to discharge was lower for group 3 (71.7%) than for group 1 (90.9%) or 2 (88.3%) (p = 0.009). For mechanically supported patients, survival to discharge was 84.6% in subgroup 3A, 71.4% in subgroup 3B, and 63.1% in subgroup 3C (p = not significant). CONCLUSIONS: Transplantation after mechanical support offers acceptable results in this group of patients for whom the only alternative is certain death. Patient selection and perioperative management remain the challenge to improving these results.

Administration, Oral↗
PubMed1996

Controlled trial of nimodipine in amyotrophic lateral sclerosis.

Calcium channel blocking drugs antagonize excitatory amino acid receptor activation, decrease calcium entry into damaged neurons, and might help to slow or reverse amyotrophic lateral sclerosis (ALS). We enrolled 87 patients with ALS in a randomized, placebo-controlled, prospective, double-blind crossover study of nimodipine therapy. Monthly measures of isometric muscle strength and respiratory function compared the effects of drug and placebo. No difference in adverse events occurred in placebo vs drug-treated patients, but diarrhoea, nausea, and lightheadedness were more common with nimodipine. There was no significant difference in the rate of decline of pulmonary function or limb strength during treatment with drug or placebo. Nimodipine was ineffective in slowing the progress of ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1996

Human aortic valve allografts elicit a donor-specific immune response.

OBJECTIVE: The nature and magnitude of the immunologic response to implantation of human cryopreserved aortic valve allografts was investigated. METHODS: Twenty aortic valve allograft recipients were investigated for donor-specific antibody and T-cell-mediated responses with serial flow cytometric and microlymphocytotoxic crossmatch assays and one-way mixed lymphocyte cultures. RESULTS: Donor-specific immunoglobulin G antibodies to class I and II human leukocyte antigens were first detected in the serum of all aortic valve allograft recipients at 30 days after implantation and persisted in substantial amounts in all but one of the recipients at day 365. Recipient T-cell alloreactivity toward donor lymphocytes was significantly increased at day 30 compared with levels before and 10 days after operation. CONCLUSIONS: Cryopreserved aortic valve allografts elicit a substantial allogeneic response in recipients. This alloreactivity may contribute to the observed morphologic changes in aortic valve allografts and eventual long-term deterioration of allograft function.

Adult↗
PubMed1996

Rifampicin antibiotic impregnation of the St. Jude Medical mechanical valve sewing ring: a weapon against endocarditis.

The Dacron sewing ring material of the St. Jude Medical mechanical heart valve (St. Jude Medical, Inc., St. Paul, Minn.) was passively impregnated with rifampicin (60 mg/ml) both in its unsealed state and after sealing by the methods of preclotting in blood, autoclaving in blood, and autoclaving in 20% albumin. Antistaphylococcal activity in the Dacron material was assessed immediately after rifampicin impregnation and at regular periods up to 5 days after implantation into the goat aorta. When the Dacron material had been sealed by autoclaving in blood and autoclaving in 20% albumin significant retention of antistaphylococcal activity was found after 5 days in vivo. Best results were obtained with the use of autoclaved blood (p < 0.05). We also compared these results with those obtained from impregnating commercially available gelatin-sealed (Gelseal) and collagen-sealed (Hemashield) Dacron material with rifampicin. Although antistaphylococcal activity was equivalent immediately after rifampicin impregnation, after 4 days in vivo the activity was negligible in Gelseal material (p < 0.05) and could not be demonstrated in Hemashield material. Rifampicin impregnation of the intact St. Jude Medical mechanical valve sewing ring may have an application in the prevention of prosthetic valve endocarditis and a clinical protocol is suggested.

Albumins↗
PubMed1996

Cyclosporine in severe childhood atopic dermatitis: a multicenter study.

BACKGROUND: Severe atopic dermatitis (AD) remains difficult to treat. Cyclosporine is effective in adults but has not previously been investigated in children with AD. OBJECTIVE: The aims were to investigate the efficacy, safety, and tolerability of cyclosporine in severe refractory childhood AD. METHODS: Subjects 2 to 16 years of age were treated for 6 weeks with cyclosporine, 5 mg/kg per day, in an open study. Disease activity was monitored every 2 weeks by means of sign scores, visual analogue scales for symptoms, and quality-of-life questionnaires. Adverse events were monitored. Efficacy and tolerability were assessed with five-point scales. RESULTS: Twenty-seven children were treated. Significant improvements were seen in all measures of disease activity. Twenty-two showed marked improvement or total clearing. Quality of life improved for both the children and their families. Tolerability was considered good or very good in 25 subjects. CONCLUSION: Cyclosporine may offer an effective, safe, and well-tolerated short-term treatment option for children with severe AD.

Administration, Oral↗
PubMed1996

A novel X-linked gene, DDP, shows mutations in families with deafness (DFN-1), dystonia, mental deficiency and blindness.

In 1960, progressive sensorineural deafness (McKusick 304,700, DFN-1) was shown to be X-linked based on a description of a large Norwegian pedigree. More recently, it was shown that this original DFN-1 family represented a new type of recessive neurodegenerative syndrome characterized by postlingual progressive sensorineural deafness as the first presenting symptom in early childhood, followed by progressive dystonia, spasticity, dysphagia, mental deterioration, paranoia and cortical blindness. This new disorder, termed Mohr-Tranebjaerg syndrome (referred to here as DFN-1/MTS) was mapped to the Xq21.3-Xq22 region2. Using positional information from a patient with a 21-kb deletion in chromosome Xq22 and sensorineural deafness along with dystonia, we characterized a novel transcript lying within the deletion as a candidate for this complex syndrome. We now report small deletions in this candidate gene in the original DFN-1/MTS family, and in a family with deafness, dystonia and mental deficiency but not blindness. This gene, named DDP (deafness/ dystonia peptide), shows high levels of expression in fetal and adult brain. The DDP protein demonstrates striking similarity to a predicted Schizosaccharomyces pombe protein of no known function. Thus, is it likely that the DDP gene encodes an evolutionarily conserved novel polypeptide necessary for normal human neurological development.

Abnormalities, Multiple↗
PubMed1996

F-actin bundles in Drosophila bristles are assembled from modules composed of short filaments.

The actin bundles in Drosophila bristles run the length of the bristle cell and are accordingly 65 microns (microchaetes) or 400 microns (macrochaetes) in length, depending on the bristle type. Shortly after completion of bristle elongation in pupae, the actin bundles break down as the bristle surface becomes chitinized. The bundles break down in a bizarre way; it is as if each bundle is sawed transversely into pieces that average 3 microns in length. Disassembly of the actin filaments proceeds at the "sawed" surfaces. In all cases, the cuts in adjacent bundles appear in transverse register. From these images, we suspected that each actin bundle is made up of a series of shorter bundles or modules that are attached end-to-end. With fluorescent phalloidin staining and serial thin sections, we show that the modular design is present in nondegenerating bundles. Decoration of the actin filaments in adjacent bundles in the same bristle with subfragment 1 of myosin reveals that the actin filaments in every module have the same polarity. To study how modules form developmentally, we sectioned newly formed and elongating bristles. At the bristle tip are numerous tiny clusters of 6-10 filaments. These clusters become connected together more basally to form filament bundles that are poorly organized, initially, but with time become maximally cross-linked. Additional filaments are then added to the periphery of these organized bundle modules. All these observations make us aware of a new mechanism for the formation and elongation of actin filament bundles, one in which short bundles are assembled and attached end-to-end to other short bundles, as are the vertical girders between the floors of a skyscraper.

Actin Cytoskeleton↗
PubMed1996

Predominance of null mutations in ataxia-telangiectasia.

Ataxia-telangiectasia (A-T) is an autosomal recessive disorder involving cerebellar degeneration, immunodeficiency, chromosomal instability, radiosensitivity and cancer predisposition. The responsible gene, ATM, was recently identified by positional cloning and found to encode a putative 350 kDa protein with a Pl 3-kinase-like domain, presumably involved in mediating cell cycle arrest in response to radiation-induced DNA damage. The nature and location of A-T mutations should provide insight into the function of the ATM protein and the molecular basis of this pleiotropic disease. Of 44 A-T mutations identified by us to date, 39 (89%) are expected to inactivate the ATM protein by truncating it, by abolishing correct initiation or termination of translation, or by deleting large segments. Additional mutations are four smaller in-frame deletions and insertions, and one substitution of a highly conserved amino acid at the Pl 3-kinase domain. The emerging profile of mutations causing A-T is thus dominated by those expected to completely inactivate the ATM protein. ATM mutations with milder effects may result in phenotypes related, but not identical, to A-T.

Amino Acid Sequence↗
PubMed1996

Seizures and status epilepticus in childhood cerebral malaria.

Prolonged, multiple seizures complicate a high proportion of cases of childhood cerebral malaria, and several studies have shown an association between these and neurological sequelae. We prospectively studied 65 patients (38 female) admitted to Kilifi Hospital in 1994. Electroencephalographic recordings (EEGs) were made at 12-hourly intervals, with continuous recordings made on a cerebral function analysing monitor (CFAM). Survivors were seen one month after discharge. Cerebral computerized tomography was performed on children with neurological sequelae. Sixty-two percent of patients had seizures following admission, of whom half had an episode of status epilepticus. Fifty-two percent of seizures were partial motor, 34% generalized tonic-clonic, and 14% partial with secondary generalization. In 22%, coma appeared to be due to a prolonged postictal state. Ten children had subtle motor seizures. Posterior parieto-temporal discharges were the most common EEG finding. Seven children died, eight developed neurological sequelae, and 50 (77%) recovered fully. Status epilepticus was associated with the development of neurological sequelae. Prolonged, multiple seizures may play an important part in the pathogenesis of coma in childhood cerebral malaria, and are likely to contribute to both the morbidity and mortality of this disease.

Brain↗
PubMed1996

Effect of transfusion on oxygen transport in critically ill patients.

The role of isolated blood transfusion as a means toward improving oxygen transport was evaluated in 19 critically ill patients having sepsis syndrome as defined by standard criteria. ICU therapies were unchanged during transfusion and hemodynamic profiles with serum lactate levels were obtained before and after packed red blood cells were given. Blood transfusions in these patients did not cause a change in hemodynamic status. Arterial lactate determination was normal before and after transfusion was administered. Oxygen uptake failed to increase with transfusion, corresponding to increased arterial and mixed venous oxygen content. In the presence of sepsis, patients having oxygen delivery and uptake above normal without evidence of ischemia (normal lactate) will not increase oxygen consumption by raising the hemoglobin.

Adult↗
PubMed1996

Selenium deficiency and miscarriage: a possible link?

OBJECTIVE: To investigate a possible relationship between a deficiency in serum selenium concentration and first trimester miscarriage. DESIGN: An observational study. SETTING: A teaching hospital in South Wales. PARTICIPANTS AND METHODS: Serum selenium, albumin and total protein concentration were measured in 40 women admitted with first trimester nonrecurrent miscarriage. The results were compared with an equal number of age-matched nonpregnant healthy volunteers, and also from 40 pregnant women attending the antenatal clinic for booking in the first trimester. RESULTS: A reduction in serum selenium normally occurs in the first trimester of pregnancies that progress to term. However, a further statistically highly significant decrease in serum selenium was observed in those women who miscarried. CONCLUSION: Further studies are required to assess the potential benefits of selenium supplements.

Abortion, Spontaneous↗
PubMed1996

A selective and differential medium for Vibrio harveyi.

A new medium, termed Vibrio harveyi agar, has been developed for the isolation and enumeration of V. harveyi. It is possible to differentiate V. harveyi colonies from the colonies of strains representing 15 other Vibrio species with this medium. This medium has been shown to inhibit the growth of two strains of marine Pseudomonas spp. and two strains of marine Flavobacterium spp. but to allow the growth of Photobacterium strains. Colonies displaying typical V. harveyi morphology were isolated from the larval rearing water of a commercial prawn hatchery with V. harveyi agar as a primary isolation medium and were positively identified, by conventional tests, as V. harveyi. This agar displays great potential as a primary isolation medium and offers significant advantages over thiosulfate-citrate-bile salts-sucrose agar as a medium for differentiating V. harveyi from other marine and estuarine Vibrio species.

Culture Media↗
PubMed1996

Acute Bordetella pertussis infection in an adult.

Bordetella pertussis was transmitted from an immunized boy to his father and possibly to other family members. This case report demonstrates that although unusual, acute adult B. pertussis infection can occur. B. pertussis immunization may not prevent infection but can reduce the severity. B. pertussis was detected in sputum from the adult by direct-fluorescent antibody staining and was grown on Regan-Lowe medium. Serology tests confirmed the infection in the adult.

Acute Disease↗