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Biomedical subjects

T Lewis

Publications and source records attributed to T Lewis.

At least 91 records · Page 5Linked to original sources
PubMed1986

Comparison of diflunisal and piroxicam in the management of patients with osteoarthritis.

An open-label comparison of diflunisal, a nonacetylated salicylate nonsteroidal anti-inflammatory drug (NSAID), and piroxicam, an NSAID belonging to the oxicam family, was conducted in patients with osteoarthritis. Efficacy assessments were made biweekly by the physician and patients during a 12-week treatment and observation period. The physician's evaluations showed that both drugs resulted in significant reductions in knee pain, tenderness, swelling, stiffness, and difficulty walking. A greater number of statistically significant differences were noted with diflunisal than with piroxicam, but there were no statistically significant differences between the two treatment groups. Patients' efficacy ratings tended to favor diflunisal, and diflunisal was significantly more effective than piroxicam in relieving night pain. Seventy-five percent of patients receiving diflunisal and 40% of those receiving piroxicam considered their condition improved after treatment; however, the proportion of good to excellent drug ratings was similar for the two drugs. Both drugs were generally well tolerated. Adverse effects were encountered in five (28%) of 18 patients given diflunisal and in four (33%) of 12 patients given piroxicam. Six patients were withdrawn from the study because of side effects, four from the piroxicam group and two from the diflunisal group. In this study, diflunisal was found to be an effective and well tolerated drug for use in the management of osteoarthritis.

Clinical Trials as Topic↗
PubMed1985

The response of rat alveolar macrophages to chronic inhalation of coal dust and/or diesel exhaust.

The use of diesel-powered equipment in underground mines has raised questions regarding possible synergistic effects of coal dust and diesel emissions. Therefore, the effects of chronic exposure of rats to coal dust and/or diesel exhaust on various properties of alveolar macrophages were investigated. Inhalation exposure of rats was 7 hr/day, 5 days/week for 2 years. Exposure groups were: filtered air controls, 2 mg/m3 coal dust, 2 mg/m3 diesel particulate, and 1 mg/m3 coal dust plus 1 mg/m3 diesel exhaust. Exposure to coal dust and/or diesel exhaust had little effect on oxygen consumption, membrane integrity, lysosomal enzyme activity, or protein content of alveolar macrophages. However, exposure to coal dust increased macrophage yield, enhanced chemiluminescence, and increased the activity of the cell membrane (i.e., increased cellular spreading and surface ruffling). In contrast, diesel emissions depressed chemiluminescence and decreased the ruffling of the cell membrane. Therefore, the data suggest that exposure to coal dust and/or diesel exhaust does not affect the viability of alveolar macrophages. However, coal dust may activate alveolar macrophages while diesel emissions may depress the phagocytic activity of these cells. The combination of exposures to coal dust and diesel exhaust results in a phagocytic activity which is an average of the effects of separate exposures.

Animals↗
PubMed1985

Genotoxicity studies of rodents exposed to coal dust and diesel emission particulates.

Genotoxicity studies with mice and/or rats have been conducted to evaluate the potential mutagenic hazard associated with exposures of coal miners to diesel emission particulates (DEP) and/or coal dusts (CD). Rats and mice were exposed to filtered air, DEP, and/or CD for periods ranging from 3 months to 2 years. Levels of respirable particulates were maintained at 2 mg/m3 in all exposed groups. DEP and/or CD were collected in the inhalation chambers in which animals were exposed. Urine samples were collected for 5 consecutive days from rats exposed to DEP and/or CD for 3, 6, and 24 months. The particulate samples extracted with dichloromethane and the urine samples concentrated with XAD-2 columns were analyzed for mutagenic activity by the Ames Salmonella/microsome assay system. Peripheral blood lymphocytes from rats exposed for 3 months were analyzed for sister chromatid exchanges (SCE). The femur bone marrow cells from rats exposed for 24 months and mice exposed for 6 months were analyzed for micronuclei in both polychromatic and normochromatic erythrocytes. The results indicate that the solvent extract of DEP was mutagenic, while no mutagenic activity was found for the CD extract. Combination of CD and DEP did not show any synergistic effect. No mutagenic activity was found for urine samples from rats exposed to DEP and/or CD for up to 2 years. A slight increase in the micronucleated polychromatic erythrocytes over the control level was found in mice exposed to DEP and DEP plus CD for 6 months but the increase was not statistically significant. No increase in micronuclei was detected in rats exposed for 24 months. The frequencies of SCE in the peripheral lymphocytes of the 3-month-exposed rats were similar for control and DEP plus CD-exposed groups.

Animals↗
PubMed1985

Verapamil inhibition of lymphocyte proliferation and function in vitro.

Calcium is a divalent cation which acts both as a cofactor for critical protein function and as a "second signal" to trigger cytosol events after membrane depolarization. The presence of calcium is critical to T-lymphocyte function. Verapamil is a calcium channel blocker at the membrane level and may affect cytosol calcium-calmodulin as well. Verapamil effect was measured on two assays of lymphocyte proliferation (concanavalin A and phytohemagglutinin lectin and alloantigen stimulated) and on cell-mediated cytotoxicity. Verapamil inhibited proliferation at 10(-5) M doses and abrogated it at 10(-4) M. Verapamil interferes with critical calcium-mediated events in T lymphocyte proliferation and function. T-lymphocyte calcium channel blockade may be an effective immunosuppressive strategy.

Animals↗
PubMed1985

The diagnostic superiority of computerized tomography.

One hundred three patients with blunt abdominal trauma were studied using computerized tomography (CT). By protocol CT was performed in hemodynamically stable adults either: before tap and lavage (T&L)--32 patients; after 'negative' (less than 20,000 RBC/mm3) or 'borderline' (20,000-50,000 RBC/mm3) lavage--28 patients; or to evaluate hematuria--43 patients. CT was performed after administration of oral and intravenous contrast. A comparison of T&L and CT was made in 60 patients. 16 of 42 patients with negative lavage had 22 injuries identified by CT. One of these patients with bilateral renal artery transection, mesenteric and pararenal hematomas died of a closed head injury. Six of 14 patients with borderline lavage results had nine injuries found on CT, including two with actively bleeding spleens confirmed at operation or angiography. One patient with a large retroperitoneal hematoma underwent successful control of hemorrhage by embolization. Only one injury, a paranephric hematoma found at operation was not identified preoperatively by CT. Seventeen of 85 patients with hematuria had GU abnormalities identified by CT. Findings included seven intrarenal hematomas or contusions, three fractures, three major renovascular injuries, four para- and six perinephric hematomas, and three collection system injuries with extravasation. The majority of these injuries were found in patients with more than 50 RBC/HPF; however, six of 47 patients with less than 20 RBC/HPF had abnormalities including a retroperitoneal bladder perforation and a renal mass (hypernephroma). Two bladder perforations and one urethral injury were identified by CT cystogram. Abdominal CT is more sensitive and specific than T&L or IVP.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Injuries↗
PubMed1984

Platelet function is altered by autogenous vein grafts in the early postoperative months.

A new animal model was used to study the effect of autogenous vein grafts on platelet function and to follow the time course of any changes. Reversed external jugular vein was grafted to the ipsilateral carotid artery in lop-eared rabbits. The platelet activation index (PAI), a measure of platelet responsiveness to adenosine diphosphate, was used to measure the effect of the graft on platelets at set postoperative times and the results compared with pre-operative values. There was a statistically significant increase in PAI in samples taken from the central ear artery at 1 week (P less than 0.005), 1 month (P less than 0.005) and 2 months (P less than 0.05) after operation, but not at 4, 6 and 8 months. In animals killed 1 week and 1 month after operation, platelets were shown to be activated following a single passage across the graft. Platelets that have been activated by the graft may in turn be involved in the process of intimal hyperplasia in the graft wall. Our results suggest that modification of the behaviour of activated platelets by drug intervention may only be required during the early postoperative months.

Adenosine Diphosphate↗
PubMed1984

Modelling the migration of Onchocerca volvulus in simuliids, using a simple compartmental process.

A simple compartmental process, which is time-homogeneous and has differing transition rates between compartments, is discussed. When such a process is hierarchical, with all individuals released into the first compartment, the resulting distribution of individuals over the various compartments is multinomial. This process is applied to the migration of Onchocerca volvulus in simuliids and appears to represent successfully the early migration from the stomach through the abdomen to the thorax, provided that allowances are made for the engorgement period and the encapsulation of the blood meal by a peritrophic membrane.

Animals↗
PubMed1981

Does anti-Jra cause hemolytic disease of the newborn?

A Jr(a-) Japanese female developed anti-Jra during her first pregnancy. Both father and infant red cells were Jr(+), and anti-Jra was eluted from the infant's red cells. The antibody was determined to be IgG1. Hemolysis could not be definitively established from the clinical data. The pitfall of using the presence of jaundice as the sole evidence for hemolysis is emphasized. We conclude that the present case, and other previously reported cases, do not unequivocally establish that anti-Jra significant hemolytic disease of the newborn (HDN). Amniocentesis probably should not be performed during the pregnancy of mothers sensitized to Jra antigen. Jra HDN is probably a mild disease, like ABO HDN.

Adult↗
PubMed1981

Characteristics of an antibody causing agglutination of M-positive non-enzymatically glycosylated human red cells.

An alloagglutinin was identified in the serum of an M-negative diabetic patient. The agglutinin reacted with all commercial M-positive red cell samples. Routine crossmatches showed no incompatibility. This anti-M would only agglutinate M-positive red cell samples that had been incubated in 2% glucose for a minimum of 2 h at 37 degrees C, 2 days at 22 degrees C, or 1 week at 4 degrees C. Reactive red cell samples, when washed and incubated in saline, gradually became non-reactive. This antibody reacted optimally in low ionic strength solution at 16 degrees C for 20 min where MM red cells were agglutinated to a titer of 256, score 85; and MN red cells were agglutinated to a titer of 128, score 66. The antibody was denatured by 2-mercaptoethanol and was inhibited by a crude M tryptic isolate and by 2% glucose, but not by other sugars prepared at a 2% concentration.

Adult↗
PubMed1981

Cyst formation in rat kidney induced by cis-platinum administration.

The long-term pathologic effects of the antitumor drug, cis-diamminedichloroplatinum II (CP) on the structure of the rat kidney were investigated. Light microscopy and transmission and scanning electron microscopy were used to characterize the morphologic changes 2 weeks, 4 weeks, and 6 months after the intraperitoneal injection of CP to rats. At all time intervals examined, the S3 segment of the proximal tubule located in the outer stripe of the medulla showed the most consistent pattern of injury. Two weeks after CP, the proximal tubules located in the outer stripe region as well as in the medullary rays were widely dilated and lined by low-lying epithelial cells, many of which contained large atypical nuclei. Many tubules still showed evidence of necrosis, whereas other tubules appeared to be undergoing atrophic changes. After 4 weeks, proximal tubular dilation continued resulting in the formation of numerous microcysts in the region of the outer stripe. These changes appeared to progress, and after 6 months large cysts (mean diameter 2152 +/- 1241 micrometer) were identified which involved the entire outer stripe, with many of these cysts extending to the subcapsular cortex. The kidneys at this time period showed a pattern of chronic renal injury in the outer stripe, and this damage was now also observed in the cortex. In several animals, small foci of abnormal foam cells surrounded by a basal lamina could be identified. We conclude that CP has a pronounced long-term effect and causes cyst formation in the rat kidney.

Animals↗
PubMed1980

A glucose-dependent panhemagglutinin.

An agglutinin was identified in the serum of a non-transfused primiparous patient that reacted with all commercial red blood cells regardless of their antigenic makeup. The autologous control was negative. The agglutinin was directed against human red blood cells that had been incubated in media containing glucose and washed prior to testing. Red blood cells incubated in 2% glucose solution became agglutinable after 6 days of 4 degrees C or after 2 h at 37 degrees C. These red blood cells gradually became non-reactive when washed and incubated in saline at 37 or 4 degrees C. At 22 degrees C the titer of the agglutinin was 128 (score 64) in LISS and 64 (score 56) in saline. The agglutinin was denatured by 2-mercaptoethanol, but remained active after 30 min of heating at 56 degrees C. Among various mono- and disaccharides tested, glucose was the only sugar that selectively inhibited the reaction. The presence of such an agglutinin may cause confusion in a transfusion service laboratory by mimicking an antibody directed against a high incidence antigen.

Adult↗
PubMed1979

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American Medical Association↗