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Biomedical subjects

B G Lewis

Publications and source records attributed to B G Lewis.

At least 19 recordsLinked to original sources
PubMed1997

Nosocomial transmission of Trichophyton tonsurans tinea corporis in a rehabilitation hospital.

OBJECTIVE: Investigate the nosocomial transmission of Trichophyton tonsurans tinea corporis. DESIGN: Descriptive study of a nosocomial epidemic of tinea corporis. SETTING: A free-standing inpatient rehabilitation facility. PARTICIPANTS: Patients and healthcare workers present on an inpatient rehabilitation ward at the time of transmission of tinea corporis. RESULTS: T tonsurans tinea corporis was transmitted from one patient to four healthcare workers despite early diagnosis and treatment. Infection rates for healthcare workers having major, moderate, and minor contact with the index case were 30%, 17%, and 0%, respectively (overall rate, 25%). CONCLUSIONS: This study identifies rehabilitation inpatients as another population in which nosocomial transmission of T tonsurans tinea corporis can occur. The high attack rate and transmission, despite early diagnosis and treatment, emphasizes the need for isolation precautions.

Adult↗
PubMed1989

The influence of polyacid molecular weight on some properties of glass-ionomer cements.

The influence of the molecular weight of the poly(acrylic acid) component on some properties of glass-ionomer cement has been investigated. The results can be explained by treatment of glass-ionomer cements as thermoplastic composites. Many of the concepts of polymer science can be applied successfully in a qualitative way to these cements, including the ideas of entanglements and reptation. Molecular weight of the polyacid had a pronounced influence on setting rate, acid erosion rate, toughness, fracture toughness, and wear resistance. The chain length of the polyacid was found to be an important parameter in formulation of a cement, and the higher the molecular weight, the better the properties. However, in practice the molecular weight is limited by viscosity, and some balance has to be achieved among concentration, molecular weight, and viscosity.

Acrylates↗
PubMed1986

Blood-CSF barrier to CCK and effect of centrally administered bombesin on release of brain CCK.

The purpose of this study, in part, was to determine the ability of cholecystokinin (CCK-33/39 and CCK-8) to penetrate the blood cerebrospinal fluid (CSF) barrier in dogs by measuring these forms of CCK in plasma and in CSF. In addition, the effectiveness of centrally administered bombesin in releasing brain CCK-33/39 and CCK-8 was evaluated. Six groups of five dogs each were studied. Each group received one of the following: (1) intravenous infusion of CCK-33/39 (1.3 micrograms/kg/hr); (2) intravenous infusion of CCK-8 (0.4 micrograms/kg/hr); (3) intrathecal infusion of CCK-33/39 (1.3 micrograms/kg/hr); (4) intrathecal infusion of CCK-8 (0.5 micrograms/kg/hr); (5) intravenous infusion of bombesin (1 micrograms/kg/hr); and (6) intrathecal infusion of bombesin (1 microgram/kg/hr). Plasma concentrations of CCK-33/39 significantly increased during intravenous infusion of CCK-33/39 (from basal of 84 +/- 8 to 142 +/- 2 pg/ml) or bombesin (from basal of 78 +/- 13 to 325 +/- 87 pg/ml); however, CSF perfusate concentrations of CCK-33/39 did not increase. CCK-33/39 levels of the CSF perfusate increased significantly (P less than .05) from 211 +/- 84 to 9,873 +/- 3,368 pg/ml during intrathecal infusion of CCK-33/39, but failed to rise simultaneously in the systemic circulation. Similarly, intravenous infusion of CCK-8 caused a fivefold elevation in plasma CCK-8 levels and no change in CSF perfusate levels of CCK-8; moreover, intrathecal infusion of CCK-8 failed to elevate peripheral CCK-8 levels, despite CSF perfusate CCK-8 levels of 92,300 +/- 18,598 pg/ml. Intrathecal concentrations of neither CCK-33 nor CCK-8 were affected by intravenous or intrathecal administration of bombesin. We conclude that CCK-33/39 and CCK-8 do not penetrate the blood-cerebrospinal fluid barrier in dogs, and centrally administered bombesin is ineffective in causing release of cholecystokinin from brain tissue into the CSF.

Animals↗
PubMed1983

The role of surgery in the Zollinger-Ellison syndrome.

When the Zollinger-Ellison syndrome was first identified, total gastrectomy was proposed as the most effective treatment for the secretory manifestations of the syndrome. Recently, however, great enthusiasm has developed for medical treatment by means of H2-receptor antagonists. The authors have cared for 27 patients with the Zollinger-Ellison syndrome at The University of Texas Medical Branch in the past 12 years and have been pleased with the results of total gastrectomy, which was performed in 23 of the 27 patients (one patient refused operation and three patients had lesser gastric operations). Twenty-three patients underwent total gastrectomy with Roux-en-Y esophagojejunostomy. There were no operative deaths. Primary tumors were found in 17 patients, seven of whom also had metastatic tumors. No tumors were found in nine patients. Nine patients are dead; the actuarial survival rate for all patients was 75% at 5 years and 52% at 10 years. Eleven of the 27 patients had the multiple endocrine neoplasia I syndrome. Of the 18 survivors, only three have normal serum gastrin levels, and all three had extrapancreatic gastrinomas, one in peripancreatic lymph nodes, one in the liver, and one in a cystic tumor attached to the stomach. Nutritional results were good to excellent, with a mean postoperative weight loss of 14.7% (mean follow-up period was 45 months). The authors conclude that treatment of the hypersecretory problems of the Zollinger-Ellison syndrome by total gastrectomy is safe and dependable. Results compare well with those of long-term medical management, whose success is dependent upon serial favorable responses to a lifetime of repeated challenges.

Adolescent↗
PubMed1982

Gastrinoma.

Explore the source record for details and available documents.

Adolescent↗
PubMed1980

The flow properties of dental cements.

The flow properties of several major types of dental cements were investigated using slow compressive strength and creep techniques. Considerable differences were found in their behavior. Whereas the phosphate-bonded and glass-ionomer cements exhibited brittle fracture, the other cements tended to distort to a greater or lesser extent under load. All cements showed some creep under load but the extent of this varied considerably; the creep of phosphate-bonded cements being very small and that of the eugenol and related cements considerable.

Dental Cements↗