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Biomedical subjects

S Parker

Publications and source records attributed to S Parker.

At least 145 records · Page 8Linked to original sources
PubMed1991

Nosocomial pneumonia in a Canadian tertiary care center: a prospective surveillance study.

OBJECTIVE: To determine the contribution of etiologic agents, including Legionella pneumophila and respiratory viruses to nosocomial pneumonia at a tertiary care center. DESIGN: Prospective surveillance of nosocomial pneumonia with standardized laboratory investigations. SETTING: A 1,100-bed tertiary care center. PATIENTS: All adult inpatients. RESULTS: One hundred and thirty-five Nosocomial pneumonias (5.7/1,000 discharges) were identified. Four (3.0%) were L pneumophila serogroup 1 infections (0.17/1,000 discharges). Legionellosis occurred in non-high-risk patients, and three cases would not have been identified without active surveillance. Viral seroconversion was identified in seven (19%) of 36 cases with specimens available (0.59/1,000 discharges): five influenza B, one influenza A, and one respiratory syncytial virus. IgM serology was positive in one case each for Mycoplasma pneumoniae and Chlamydia species. No geographical clustering was observed for viral infections, and these would not have been identified without active surveillance. Mortality for all nosocomial pneumonia was 25%. Patient factors significantly associated with a poorer outcome included older age, underlying disease, low serum albumin, renal insufficiency, lower platelet count, endotracheal intubation, respiratory failure, bacteremia, and use of antacids. CONCLUSIONS: This prospective surveillance suggested that L pneumophila and viral agents were uncommon causes of nosocomial pneumonia at our institution during this surveillance period.

Adult↗
PubMed1991

Monitoring of spinal cord stimulation evoked potentials during thoracoabdominal aneurysm surgery.

Repair of a thoracoabdominal aneurysm involves a significant risk of ischemic injury to the spinal cord. Standard monitoring of somatosensory evoked potentials, which relies upon peripheral nerve stimulation, becomes nonspecific and insensitive during this surgery when aortic cross-clamping produces lower extremity ischemia causing a peripheral conduction block. Techniques for the insertion of percutaneous epidural electrodes, developed originally for pain management, have been adapted to this setting to permit direct stimulation of the spinal cord for intraoperative monitoring of evoked potentials. The clinical outcome in patients monitored by this technique has been consistent with evoked potential findings.

Aorta, Abdominal↗
PubMed1991

Use of an impedance meter for measuring airways responsiveness to histamine.

We compared spirometry (FEV1) and airway impedance (z) in the assessment of airway responsiveness to histamine. Airway impedance was measured by the oscillator technique during quiet breathing; both measurements were made twice after each increment of histamine during the challenge. Percentage change in impedance was related to percentage change in FEV1 according to: -delta z = 1.09-2.66 (delta FEV1), r = -0.73, p less than 0.01, ie, impedance increased on average 2.7 times as much as FEV1 fell. The cut-off point for the standard test is the histamine concentration giving a 20 percent fall of FEV1 (PC20(FEV1)). The corresponding cut-off value chosen for impedance was a 30 percent increase (PC30(z)). (PC30(z)) = 0.74 (PC20(FEV1))-0.48, rs = 0.88, where rs is the Spearman rank correlation coefficient. Thus, impedance is a more sensitive index than FEV1 because a smaller dose of histamine gave a diagnostic result. Impedance is a practical alternative to FEV1, being less arduous for the patient and requiring little cooperation.

Adult↗
PubMed1991

Minor skin surgery. Are prophylactic antibiotics ever needed for curettage?

Curettage of skin lesions was not followed by bacteraemia in 22 patients. The risk of bacterial endocarditis after curettage and other minor skin surgery is small but should not be overlooked in those with a prosthetic heart valve, a history of other cardiac surgery, a previous episode of infective endocarditis, drug addiction, diabetes, alcoholism, immunosuppression, or renal failure--especially where the skin lesion might be infected.

Anti-Bacterial Agents↗
PubMed1990

Soft prosthesis materials based on powdered elastomers.

A new class of soft prosthesis material has been developed, based on the combination of a powdered elastomer and a methacrylate monomer that polymerizes to an elastomer. Such systems are processable by conventional dental technology. This principle avoids the use of plasticizers. Natural rubber, butadiene styrene and butadiene acrylonitrile elastomers have been used, together with a number of higher alkyl methacrylates (C8-C13) and 2-ethoxyethyl methacrylate. Such systems have been evaluated with respect to mechanical properties, including tear strength, adhesion to denture base poly(methyl methacrylate), water sorption and visco-elastic properties. A number of potentially viable systems have emerged, which may be useful in external prostheses. Many have high long-term water absorption, which makes questionable their long-term usefulness interorally. Nevertheless, there is still considerable scope for development in this area.

Absorption↗
PubMed1990

Formulation of tissue conditioners.

Dental tissue conditioners are compliant gels, formed in situ under a denture from a polymer powder and a plasticizer system. Hitherto, the powder has been poly(ethyl methacrylate) and the liquid a phthalate/ethanol mixture. These materials are temporary, because they harden from plasticizer leaching. The current work has been aimed at producing material with extended oral lifetimes. A range of n-butyl/ethyl methacrylate copolymers have been studied, together with various ester-ethanol liquid systems, with respect to gelation behaviour with various alcohols and esters, viscoelastic behaviour of the set gels, and water extraction. Materials based on poly(ethyl methacrylate) show that gelation speed depends upon particle size, and the degree of ball milling of the powder, and the molar volume of the plasticizer. Systems based on n-butyl/ethyl methacrylate copolymers need less or no ethanol in the liquid system, although gelation speed is very temperature dependent. The gels from these last materials are more compliant, and retain their compliance longer in aqueous media than those based on poly(ethyl methacrylate).

Biocompatible Materials↗
PubMed1990

Neonatal body proportionality and body composition after in utero exposure to cocaine and marijuana.

The relationship of maternal use of marijuana and cocaine during pregnancy to measures of neonatal body proportionality and body composition was assessed in a multiethnic sample of 1082 newborn infants. Maternal use of marijuana and cocaine during pregnancy was ascertained by self-report and by an enzyme-multiplied immunoassay technique for screening of urine samples obtained prenatally and again post partum. After each substance was analytically controlled for use of the other and for other potentially confounding variables, detection of marijuana metabolites in maternal urine was associated (p less than 0.05) with depressed mean arm muscle circumference and nonfat area of the arm but not with any measure of neonatal fatness. In contrast, detection of cocaine in maternal urine was associated (p less than 0.05) with decrements of subscapular fat folds and of the fat and nonfat areas of the arm. Although both substances were associated with depressed birth weight, there was no decrement of neonatal ponderal index or of the arm circumference/head circumference ratio in association with exposure to either substance. We conclude that both marijuana exposure and cocaine exposure during pregnancy are associated with symmetric intrauterine growth retardation, but that deficits are in differing compartments of intrauterine growth. These findings suggest that marijuana may retard fetal growth through maternal-fetal hypoxia, whereas cocaine may alter nutrient transfer to the fetus and fetal metabolism.

Adipose Tissue↗
PubMed1990

A double-blind, placebo-controlled study of oral acyclovir in postherpetic neuralgia.

Twenty-one patients with postherpetic neuralgia of two- to 84-months duration participated in a double-blind, placebo-controlled study of oral acyclovir. Pain perception was assessed with the Melzack Pain Questionnaire at baseline and at two-to six-week intervals during the ensuing six months. Clinically significant pain reduction occurred in eight patients: four received acyclovir, and four received a placebo. Several treatment strategies have been advocated for relief of postherpetic neuralgia. Results of the present study demonstrate the need for a double-blind, placebo-controlled paradigm to substantiate the efficacy of new clinical approaches. The same caveat applies to the more common syndromes encountered in psychiatric practice.

Acyclovir↗
PubMed1990

Evaluation of the need for follow-up in an out-patient clinic.

We have identified 164 patients regularly attending a chest clinic whose condition had been defined as stable on the basis of clear-cut criteria. These patients were randomly allocated to either routine follow-up at 3 monthly intervals (the 'follow-up' group) or annual follow-up (the 'discharge' group). After 1 year, on the basis of a questionnaire sent to the patients' general practitioners, there were no significant differences in outcome between the two groups apart from a just-significant increase in deaths in the 'follow-up' group. Nevertheless, at the conclusion of the trial clinic doctors felt that only 45% of patients and general practitioners that only 27% of patients should be discharged from the clinic. At the conclusion of the study patients in the 'discharge' group were significantly more likely to feel that they had been attending too infrequently and that their condition had worsened, although the latter was not borne out by objective data. We suggest that all these patients could have been discharged from the clinic without any difference in outcome. This study highlights the reluctance of clinic doctors and general practitioners to consider and effect the discharge of stable patients from routine clinic attendance.

Ambulatory Care Facilities↗
PubMed1990

Influence of single and multiple doses of oral ranitidine on the gastric transit of an indigestible capsule in humans.

The effect of single and multiple doses of ranitidine on the gastric residence time of an indigestible pH-sensitive radiotelemetric device, the Heidelberg capsule, was evaluated in 12 healthy men (mean age, 29 +/- 8 years) in a placebo-controlled, randomized, crossover study. Each subject received 150 mg ranitidine or placebo orally 2 hours before administration of the Heidelberg capsule. A 500 kcal standardized breakfast was served 1/2 hour before the capsule was administered. Gastric pH was monitored at 15-minute intervals, until pyloric passage (pH increase greater than or equal to 3 U) of the Heidelberg capsule was observed. Blood samples (n = 12) were collected 0 to 8 hours after administration of drug or placebo. The subjects continued to receive ranitidine or placebo b.i.d. for 7 days and returned on day 8 for a similar evaluation. After a 1-week washout period, the subjects received the alternative treatment. The mean (+/- SD) gastric residence time of the Heidelberg capsule was significantly decreased after both single and multiple doses of ranitidine compared to placebo (3.1 +/- 0.9 versus 3.8 +/- 1.1 hours, p less than 0.02; and 2.9 +/- 0.74 versus 3.9 +/- 0.9 hours, p less than 0.005, n = 9). Gastric residence time was not determined in three subjects who showed unusually slow gastrointestinal motility after both placebo and ranitidine. Mean AUC(0-8 hr) and AUC(0-infinity) were significantly increased, whereas Cmax, tmax, and t1/2 remained unchanged after 7 days of ranitidine b.i.d. treatment. No ranitidine double-peak profile or linear pharmacokinetic-pharmacodynamic relationship was identified.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1990

Paget's disease of bone and previous pet ownership in the United States: dogs exonerated.

Paget's disease of bone is currently believed to be the result of a paramyxovirus infection of osteoclasts. Previously reported immunohistological data have suggested that a virus resembling either the measles virus or a respiratory syncytial virus is the probable causative agent, but no organism has been isolated or definitively identified to date. A recent study reporting an increased exposure to dogs during childhood and adolescence in a small series of cases from the North West of England proposed that a canine virus, possibly distemper, might be the primarily infectious agent. To study this hypothesis further, we examined prior dog and cat ownership from childhood through adulthood in 433 cases of Paget's disease and an equal number of matched controls living in the US. We found no differences related to prior pet ownership. We conclude that past dog (or cat) ownership is not a risk factor for the development of Paget's disease.

Adolescent↗
PubMed1990

Making it better.

Explore the source record for details and available documents.

Adaptation, Psychological↗
PubMed1990

Antituberculous drug resistance in central Haiti.

To determine the prevalence of antituberculous drug resistance in Haiti, we conducted a 1-yr survey in a central district. From a bacillary positive (smear and/or culture positive) case rate of 80/100,000, there were 282 patients from whom Mycobacterium tuberculosis was cultured. Each isolate was packaged and delivered to Canada where speciation and drug susceptibility testing were performed. Reported resistances are those using the proportions method (Laboratory Center for Disease Control, Ottawa, Canada). Resistance to one or more drugs was found in 22% of isolates. Age was the most important predictor of resistance in Haiti; resistance rates for age groups less than 14, 14 to 29, 30 to 44, greater than or equal to 45 were 8, 19, 22, and 31%, respectively. In patients not known to have received antituberculous drugs in the past, resistances were isoniazid (19%), streptomycin (5%), ethambutol (2%), ethionamide (2%), rifampin (1%). We conclude that antituberculous drug resistance is prevalent in Haiti, especially in older age groups, and that in persons with no known antituberculous drug use in the past, resistance to isoniazid is significant.

Adolescent↗
PubMed1990

Partial hospitalization: an update.

As a treatment modality for serious mental disorders, partial hospitalization has been proven to have therapeutic and economic advantages. However, it has relatively low utilization and poor third-party reimbursement compared to the more traditional outpatient and inpatient treatments. The authors provide a review and update of the definitions, historical development, models, staffing, and referral patterns of partial hospitalization. They comment on the role of the psychiatrist as a member of the multidisciplinary team in this treatment setting.

Day Care, Medical↗
PubMed1990

Intensity discrimination and loudness for tones in broadband noise.

In two previous papers (Parker & Schneider, 1980; Schneider & Parker, 1987), we developed a model, based on Fechner's assumption, which successfully predicted the relationship between loudness and intensity discrimination for tones presented in quiet and in notched noise. In the present paper, pure-tone intensity-increment thresholds and loudness matches were determined for several levels of a standard tone in the presence of a broadband masker whose spectrum level was set to 35 dB below that of the standard tone. The model was unable to relate loudness to intensity discrimination under these conditions. Thus, the spectral composition of the masker affects the relationship between loudness and intensity discrimination in ways that cannot be accounted for by the model.

Adult↗