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S Smith

Publications and source records attributed to S Smith.

At least 361 records · Page 20Linked to original sources
PubMed1997

Effect of ocular perfusion pressure on retinal function in the rabbit.

The electroretinogram (ERG) vs perfusion pressure relation was studied in anesthetized rabbits during mechanically induced changes in mean arterial pressure (MAP). After 1 hr of dark adaptation, ERGs were obtained at perfusion pressures from 10 to 95 mmHg with each pressure held for 30-60 sec, and at three levels from 15 to 75 mmHg with each pressure held for 5 min. The slopes of the b-wave amplitude vs perfusion pressure data were not significantly different from zero during either the brief or longer manipulations of perfusion pressure. However, the b-wave was nearly extinguished 5 min after death. The results indicate that the rabbit ERG is maintained over a wide range of perfusion pressure.

Animals↗
PubMed1997

House dust mite allergen levels in public places in New Zealand.

BACKGROUND: House dust mite allergens are a risk factor for asthma in New Zealand, and levels in domestic dwellings have been found to be high compared with levels in most other countries. Studies in other countries have demonstrated lower levels of Dermatophagoides pteronyssinus allergens in public places compared with levels in domestic dwellings. OBJECTIVES: The purpose of this study was to measure reservoir Der p 1 levels in public places in New Zealand and to examine determinants of these levels. METHODS: Reservoir dust was obtained in the two centers (Christchurch and Wellington) from hotels, hospitals, rest homes, churches, primary schools, childcare centers, cinemas, bank head offices, and airplanes; samples were also obtained from ski lodges. Single measurements of temperature and relative humidity were taken with thermohygrometers and an average humidity over 2 weeks was estimated with use of waxed wooden sticks. Information was collected on building construction, type of heating, and frequency of cleaning. Der p 1 levels (micrograms per gram of fine dust) for floor (n = 202), bed (n = 65), and seat (n = 24) samples in public places were expressed as geometric means (95% confidence intervals). RESULTS: Der p 1 levels in public places were significantly lower than domestic levels in both Wellington and Christchurch. Both floor and bed levels were higher in hotels than in other public places. After controlling for potential confounders, floor Der p 1 levels were higher with carpeted floors (p < 0.0001) and lower with recent cleaning (p = 0.02) and bed Der p 1 levels were higher with timber wall construction (p = 0.03). Other building, heating, or cleaning characteristics did not show significant association with allergen levels. CONCLUSION: Der p 1 levels were much lower in public places than in domestic dwellings with floor levels primarily affected by floor covering.

Allergens↗
PubMed1997

Use of herbal products, coffee or black tea, and over-the-counter medications as self-treatments among adults with asthma.

BACKGROUND: There are few data on the use of alternative therapies in adult asthma and their impact on health outcomes. OBJECTIVE: The objective of this study was to study the prevalence and morbidity of asthma self-treatment with herbs, coffee or black tea, and over-the-counter (OTC) medications containing ephedrine or epinephrine. METHODS: We carried out a cross-sectional analysis of interview data for 601 adults with asthma recruited from a random sample of pulmonary and allergy specialists. We estimated the 12-month prevalence of reported use of herbal products, coffee or black tea, or OTC products to self-treat asthma and their association with emergency department visits and hospitalization. RESULTS: Herbal asthma self-treatment was reported by 46 (8%; 95% confidence interval [CI] 6% to 10%); coffee or black tea self-treatment by 36 (6%; 95% CI 4% to 8%), epinephrine or ephedrine OTC use by 36 (6%; 95% CI 4% to 8%), and any of the three practices by 98 subjects (16%; 95% CI 13% to 19%). Adjusting for demographic and illness covariates, herbal use (odds ratio [OR] 2.5; 95% CI 1.1 to 5.6) and coffee or black tea use (OR 3.1; 95% CI 1.2 to 7.8) were associated with asthma hospitalization; OTC use was not (OR 0.8; 95% CI 0.3 to 2.5). CONCLUSIONS: Even among adults with access to specialty care for asthma, self-treatment with nonprescription products was common and was associated with increased risk of reported hospitalization. This association does not appear to be accounted for by illness severity or other disease covariates. It may reflect delay in utilization of more efficacious treatments.

Adolescent↗
PubMed1997

TRF1, a mammalian telomeric protein.

Telomerase adds TTAGGG repeats onto mammalian chromosome ends, replenishing the terminal sequence loss incurred during DNA replication. This maintenance of telomeric DNA preserves binding sites for telomeric proteins, which form a protective nucleoprotein complex at chromosome ends. The recent isolation of TRF1, the mammalian telomeric-repeat binding factor, should now allow the structure and function of the telomeric complex to be examined in detail.

Amino Acid Sequence↗
PubMed1997

A comparison of duplex scanning and continuous wave Doppler in the assessment of primary and uncomplicated varicose veins.

OBJECTIVES: To compare the findings of continuous wave Doppler (CWD) with duplex ultrasound in the assessment of primary and uncomplicated varicose veins, and to determine how their relative roles might be best applied. MATERIALS AND METHODS: One hundred consecutive limbs were studied in 73 patients with primary (no previous surgery) and uncomplicated (no significant skin change) varicose veins. CWD was employed by a single observer; followed by duplex scanning performed "blind" and independently. RESULTS: There were 87 limbs with long saphenous incompetence on duplex; all but four of which were correctly identified by CWD, by which technique there were no false positives. (Sensitivity 95%, specificity 100%.) There were 21 limbs with short saphenous incompetence on duplex, all but two of which were recognised on CWD. However, CWD incorrectly diagnosed reflux at the saphenopopliteal junction in five limbs (false positives) with what was, in fact, segmental reflux in the long saphenous trunk on duplex (sensitivity 90%, specificity 93%.) This would have led to inappropriate exploration of the saphenopopliteal junction had surgery proceeded without checking with duplex. CONCLUSIONS: CWD is adequate for long saphenous incompetence. All "reflux" demonstrated on CWD in the popliteal fossa (about 25% of cases) should be checked by duplex. If this policy had been followed, all the patients in this study would have undergone the correct procedure. The only "errors" would have been missing coexistent short saphenous incompetence in two limbs undergoing appropriate long saphenous exploration.

Female↗
PubMed1997

Bridging the gap between inpatient and outpatient providers using organizational elements of assertive community treatment.

Even among comprehensive local public mental health systems, there remain large gaps in continuity of care following discharge from inpatient settings. The authors describe a modification of the assertive community treatment (ACT) program model that links inpatients to ongoing community-based care, and provide preliminary evidence of its effectiveness as a component in a rationally organized comprehensive system of care. Given the recent trend toward managed Medicaid arrangements, there will be increased pressure to reduce clients' length of stay in ACT programs. State mental health authorities are cautioned to resist allowing managed care contractors to radically change the conditions under which ACT programs operate until there is greater evidence of the effectiveness of alternative approaches.

Academic Medical Centers↗
PubMed1997

Antioxidant deficiency following clam enterocystoplasty.

OBJECTIVE: To assess whether there is a reduction in serum antioxidant activity in patients who have undergone a clam enterocystoplasty procedure. PATIENTS AND METHODS: Serum glutathione peroxidase (GPase) activity was measured in 20 patients who had undergone clam enterocystoplasty. Serum selenium concentration was also measured in 62 similar patients and compared with 56 healthy controls and 44 patients with a neuropathic bladder, mainly patients with spinal cord injuries who had not undergone surgery. RESULTS: GPase activity correlated well with serum selenium measurement. There was a significant reduction (P < 0.001) in serum selenium level in young (< 50 years old) non-neuropathic bladder patients following clam enterocystoplasty. This reduction in serum selenium was similar to that found in both unoperated patients with a neuropathic bladder (who are known to have an increased risk of developing bladder cancer) and those patients with a neuropathic bladder who had undergone augmentation. This reduction was not related to urinary tract infection nor the time since surgery. CONCLUSION: A reduction in serum selenium has been shown to increase susceptibility to bladder cancer following carcinogenic exposure to compounds such as nitrosamines. This study suggests that patients with idiopathic and congenital instability may be at an equally high risk as a result of undergoing this procedure.

Adolescent↗
PubMed1997

Impact of skull fracture on neuropsychological functioning following closed head injury.

The role of skull fracture in affecting morbidity following closed head injury (CHI) has received a significant amount of attention from researchers. While there is fairly widespread agreement that skull fractures increase the risk of complications such as haematoma, it us unclear whether the presence of skull fracture has predictive value in terms of the neuropsychological sequelae of CHI. The purpose of the current study was to further investigate the role of skull fracture in predicting neuropsychological dysfunction following CHI. Subjects included patients admitted to the trauma service of a large teaching hospital who were suspected of having suffered CHI. All patients completed neuropsychological testing and had normal computerized tomography (CT) scans. Patients who had suffered skull fracture were compared to those who had not suffered skull fracture on selected neuropsychological measures. Groups did not differ in terms of CHI severity as assessed by the Glasgow Coma Scale (GCS). Multivariate analysis of variance revealed that the groups did differ in terms of neuropsychological functioning. Results are interpreted as suggesting that the presence of a skull fracture is predictive of additional neuropsychological dysfunction, even in the absence of intracranial pathology or more severe disturbance of consciousness on the GCS.

Adult↗
PubMed1997

A novel locus for autosomal dominant nonsyndromic hearing loss, DFNA13, maps to chromosome 6p.

Nonsyndromic hearing loss (NSHL) is the most common type of hearing impairment in the elderly. Environmental and hereditary factors play an etiologic role, although the relative contribution of each is unknown. To date, 39 NSHL genes have been localized. Twelve produce autosomal dominant hearing loss, most frequently postlingual in onset and progressive in nature. We have ascertained a large, multigenerational family in which a gene for autosomal dominant NSHL is segregating. Affected individuals experience progressive hearing loss beginning in the 2d-4th decades, eventually making the use of amplification mandatory. A novel locus, DFNA13, was identified on chromosome 6p; the disease gene maps to a 4-cM interval flanked by D6S1663 and D6S1691, with a maximum two-point LOD score of 6.409 at D6S299.

Adolescent↗
PubMed1997

Cost-effectiveness of hepatitis A vaccination in healthcare workers.

OBJECTIVE: To study the cost-effectiveness of vaccination for hepatitis A. SETTING: Hypothetical analysis of students currently enrolled in medical school in the United States. METHOD: A Markov-based model was developed using data from the literature, actual hospital costs, and an annual discount rate of 5%. The incidence rate was based on the lowest annual rate for the US population during the past decade. RESULTS: Over the lifetimes of students currently in medical school, the model estimated that there would be 286 hepatitis A cases with four deaths and 107 lost years of life. With routine vaccination, these numbers would decrease to 17, 0.3, and 6, respectively. The costs per life-year saved and quality adjusted life-year saved were $58,000 and $47,000, respectively. Serologic screening prior to vaccination was less cost-effective than universal vaccination. If the incidence of hepatitis A was underestimated by a factor of 5, the cost per life-year saved would decrease to $5,500. If the incidence of hepatitis was underestimated by a factor of 10, vaccination would result in a net cost savings. CONCLUSION: We conclude that the cost per life-year saved by routine hepatitis A vaccination was similar to many other standard medical modalities. For routine vaccination of medical students to be cost-saving, the incidence rate for hepatitis A must be at least 10 times higher than the rate presently reported for the general population. Serological screening prior to vaccination was not cost-effective.

Adult↗
PubMed1997

Circulating antioxidant concentrations in children with inflammatory bowel disease.

The mechanisms by which inflammatory bowel disease causes chronic injury to the gastrointestinal tract are poorly understood. To determine whether antioxidant defenses might be altered, we evaluated plasma antioxidant concentrations in 24 children with inflammatory bowel disease (12 with Crohn disease and 12 with ulcerative colitis) and in 23 healthy control subjects. Anthropometric measurements and disease activity scores were obtained. The groups were of similar age and sex distribution; most children had quiescent or mild disease. The children with Crohn disease were malnourished compared with the ulcerative colitis and control groups. Children with inflammatory bowel disease had decreased plasma ascorbic acid and increased glutathione peroxidase, glutathione, and alpha-tocopherol (vitamin E) concentrations compared with control subjects. These differences were found primarily in the children with Crohn disease. This study provides evidence that children with Crohn disease have alterations in circulating antioxidant defenses, possibly related to an ongoing oxidant stress.

Adolescent↗
PubMed1997

Blood loss during first trimester termination of pregnancy: comparison of two anaesthetic techniques.

We have compared the effects of two anaesthetic techniques on blood loss during suction termination of pregnancy. Forty-eight ASA grade I-II patients were allocated randomly to one of two groups: group 1 received propofol induction followed by a standard propofol infusion; group 2 received propofol induction followed by maintenance with 1% isoflurane. Both groups received bolus doses of either propofol (group 1) or isoflurane (group 2) if anaesthesia was too light. All patients were given fentanyl 1 micrograms kg-1 on induction. The products of conception were evacuated into a closed suction bottle. The products were diluted with 500 ml of heparinized saline, filtered and left for 20 min. Estimation of blood loss was performed by atomic absorption spectrometry. Mean blood losses were 40.4 ml for the isoflurane group and 18.8 ml for the propofol group. This difference was statistically significant (P = 0.0011), although actual volumes of blood loss were small and not clinically significant.

Abortion, Induced↗
PubMed1997

Characterization of the malonyl-/acetyltransacylase domain of the multifunctional animal fatty acid synthase by expression in Escherichia coli and refolding in vitro.

cDNAs of various lengths encoding the second domain of the multifunctional fatty acid synthase (FAS) have been expressed in Escherichia coli and the recombinant proteins refolded in vitro to catalytically active monomeric malonyl-/acetyltransacylases. FAS residues 428-487, previously thought to represent the amino terminus of the malonyl-/acetyltransacylase, can be omitted from the recombinant enzyme with no loss in catalytic activity. This shortened transacylase, consisting of FAS residues 488-809, can be repeatedly denatured and renatured in vitro with reproducibly high recovery and no loss in specific activity. When expressed as a soluble enzyme in Spodoptera frugiperda cells, this transacylase has the same specific activity as the enzyme that has been refolded in vitro. The refolded transacylase consisting of FAS residues 488-809, but not the longer enzyme consisting of residues 428-815, can be crystallized readily. These results suggest that FAS residues 428-487, previously thought to represent the amino terminus of the malonyl-/acetyltransacylase, are not required for catalysis of the transacylase reaction. This region of the FAS is less well conserved than the transacylase catalytic domain and may constitute an extended structural linker that facilitates the functional interaction between the transacylase and acyl carrier protein domains.

Acetyl-CoA C-Acyltransferase↗
PubMed1997

Intersporal Genetic Variation of Gigaspora margarita, a Vesicular Arbuscular Mycorrhizal Fungus, Revealed by M13 Minisatellite-Primed PCR.

Spores of vesicular arbuscular mycorrhizal (VAM) fungi contain thousands of nuclei. In order to understand the karyotic structure of a VAM fungus spore, the genetic variation of the first generation of spores from a VAM fungus (Gigaspora margarita) was examined. Spores originating from both single- and multispore inoculations of the species G. margarita were analyzed by M13 minisatellite-primed PCR. In both cases, different fingerprints were obtained from individual spores with few spores exhibiting similar fingerprints. These results can be explained only by a heterokaryotic status of the nuclear population within a spore.

Journal Article↗
PubMed1997

Specificity of the high-mannose recognition site between Enterobacter cloacae pili adhesin and HT-29 cell membranes.

Enterobacter cloacae has been implicated as one of the causative agents in neonatal infection and causes a septicemia thought to be initiated via the gastrointestinal tract. The adhesion of radiolabeled E. cloacae to HT-29 cells was concentration and temperature dependent and was effectively blocked by unlabeled bacteria or by millimolar concentrations of alpha-mannosides and micromolar concentrations of high-mannose oligosaccharides. A variety of well-characterized mannose oligosaccharides were tested as inhibitors of adhesion. The best inhibitor was the Man9(GlcNAc)2-tyrosinamide, which was considerably better than other tyrosinamide-linked oligosaccharides such as Man7(GlcNAc)2, Man6(GlcNAc)2 or Man5(GlcNAc)2. Further evidence that the bacteria preferred Man9(GlcNAc)2 structures was obtained by growing HT-29 cells in the presence of glycoprotein processing inhibitors that block mannosidase I and increase the amount of protein-bound Man9(GlcNAc)2 at the cell surface. Such cells bound 1.5- to 2-fold more bacteria than did control cells. The adhesin involved in binding to high-mannose structures was purified from isolated pili. On sodium dodecyl sulfate-gels, a 35-kDa protein was identified by its specific binding to a mannose-containing biotinylated albumin. The amino acid sequences of several peptides from the 35-kDa subunit showed over 85% identity to FimH, the mannose-specific adhesin of Salmonella typhimurium. Pili were labeled with 125I and examined for the ability to bind to HT-29 cells. Binding showed saturation kinetics and was inhibited by the addition of Man9(GlcNAc)2-tyrosinamide but not by oligosaccharides with fewer mannose residues. Polyclonal antibody against this 35-kDa protein also effectively blocked adhesion of pili or E. cloacae, but no effect was observed with nonspecific antibody. These studies demonstrate that the 35-kDa pilus subunit is a lectin whose specificity is directed toward Man, (GlcNAc)2 oligosaccharides.

1-Deoxynojirimycin↗