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Biomedical subjects

E Smith

Publications and source records attributed to E Smith.

At least 343 records · Page 19Linked to original sources
PubMed1983

Osteogenic sarcoma: alterations in the pattern of pulmonary metastases with adjuvant chemotherapy.

The number and time to appearance of pulmonary metastases were evaluated in 15 patients with osteogenic sarcoma receiving adjuvant chemotherapy with high-dose methotrexate and doxorubicin (adjuvant group). The results were compared to 33 age- and sex-matched controls (control group). The adjuvant group demonstrated a reduction in the number and a delay in the appearance of the metastases. The median time to development of metastases was 17 mo in the adjuvant group and 7 mo in the control group, and the median number of metastases was 2 and 12, respectively.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Case-control study of Mastomys natalensis and humans in Lassa virus-infected households in Sierra Leone.

Lassa virus infection and antibodies were studied in households where Lassa fever cases occurred, and compared to those in nearest neighbor houses and "far" houses located across the village from case houses. Seventy-nine percent of all rodents caught in the houses were Mastomys, the natural reservoir of Lassa virus. Rodent infection was not randomly distributed, but rather focal. Thirty-nine percent of the Mastomys in case houses were viremic, compared to 3.7% in control houses. Human antibody prevalence in case houses was 30%, compared to 20% in non-case houses (P less than 0.05, chi-square test, df = 2). Neither seroconversions nor antibody prevalence rates were associated with household size or number of persons per room. Trapping of rodents in half of the case and control houses resulted in a Mastomys reduction ranging from 2.2- to 3.3-fold. This reduction failed to significantly reduce the seroconversion rate to Lassa virus in the people of trapped houses compared to those in untrapped ones. More complete trapping will be needed in order to better evaluate this procedure as a means of interruption of Lassa virus transmission in endemic villages.

Animals↗
PubMed1983

Pharmacological studies on droxicainide, a new antiarrhythmic agent.

The antiarrhythmic, local anesthetic and acute local and systemic toxic effects of DL-N-(2-hydroxyethyl)-pipecolinyl-2,6-dimethylanilide (AL-S-1249, droxicainide) and lidocaine were compared in animals. When given intravenously both substances suppressed ouabain-induced arrhythmias in pentobarbital-anesthetized guinea pigs; they were equipotent in this regard and had the same duration of antiarrhythmic action. Both substances produced generally equivalent sensory anesthesia following intradermal administration in the guinea pig and corneal application in the rabbit and block of motor and sensory function when injected near the sciatic nerve in the rat. In these local anesthetic tests and following intradermal administration to rabbits, droxicainide produced less local tissue irritation than lidocaine. When given intravenously to unanesthetized mice and unanesthetized and pentobarbital-anesthetized rats, the LD50's for droxicainide were consistently higher than those for lidocaine. Since droxicainide has antiarrhythmic and local anesthetic properties that are quantitatively similar to lidocaine but local and systemic toxicity that is relatively weaker, its antiarrhythmic and local anesthetic actions merit further study.

Anesthesia↗
PubMed1982

Enhancing effect of pre-treatment of cells with misonidazole in hypoxia on their response to melphalan in air.

Pre-treatment of hypoxic cells with misonidazole (MISO) can render these cells more sensitive to a subsequent treatment with melphalan. Results in this paper show that this enhancement (or chemopotentiation) depends on the contact time and concentration of MISO, on the melphalan concentration and also on the cultural history of the cells. Damage due to hypoxic pre-incubation in MISO can be repaired if cells are subsequently aerated at 37 degrees C. In contrast, for cells washed free of MISO and then held under N2 at 37 degrees C, repair is much slower. No repair occurs when cells are held in air at 0 degrees C. The kinetics and extent of repair were dependent on the cells prior culture. Thus for exponential cells repair was complete after approximately 4 h, whereas for plateau-phase cells and cells with prior chronic hypoxia, repair was only partially complete after this time. Dithiothreitol was shown to protect partially against the enhancement of melphalan toxicity. Increased cell killing is also obtained if cells are given high concentrations of MISO (50 mM) in air during exposure to melphalan.

Animals↗
PubMed1982

Dynamic cholecystosonography of the contracted gallbladder: the double-arc-shadow sign.

In 41 of 55 patients in whom the gallbladder lumen was not identified by static sonography, a specific image was observed with dynamic scanning. This consisted of two parallel arcuate echogenic lines separated by a thin anechoic space with distal acoustic shadowing: the "double-arc-shadow" sign. The proximal arc represents the near wall of the gallbladder, the anechoic space is bile in the gallbladder lumen, and the distal arc represents the gallstone(s) responsible for the acoustic shadowing. Of the two additional sonographic patterns observed, the "'echo-shadow" pattern, which was seen with static scanning in 44 and with dynamic scanning in eight patients was an accurate, indirect indicator for cholelithiasis. On the other hand, "nonvisualization" was an unreliable sign. Of 11 such patients scanned with static and six with dynamic scanning, four proved to have a normal gallbladder. Comparing static with dynamic cholecystosonography in patients with nonphysiologically contracted gallbladders, the accuracy rate for cholelithiasis increased from 86.3% (44 of 51 patients) to 96% (49 of 51). In 41 of these patients (80%) the double-arc-shadow pattern positively identified the gallbladder lumen, increasing the confidence of the examiner. Furthermore, these images can be produced in a fraction of the time required for complete evaluation with static scanning.

Cholelithiasis↗
PubMed1982

A candidate reference method for uric acid in serum. I. Optimization and evaluation.

We describe our optimization and evaluation of a candidate Reference Method for uric acid in serum. Reaction parameters were optimized for a manual, enzymic method for uric acid in which highly purified microbial uricase is used to quantitate uric acid by a differential ultraviolet procedure. We evaluated the method in terms of freedom from interferences, analytical recovery, precision, and comparison with five other uric acid methods. We conclude that (a) the candidate uric acid Reference Method exhibits the least interference; (b) all six methods exhibit satisfactory analytical recoveries and precision; and (c) results by all six methods agree well. As a result of this evaluation study, the manual ultraviolet uricase method for uric acid, with Tris as buffer, was chosen as the candidate Reference Method for uric acid.

Adult↗
PubMed1981

Tumor growth and regression rates relative to tumor size: a clinical study of metastatic pulmonary nodules.

Patients with multiple discrete metastatic pulmonary nodules were serially monitored and tumor growth and regression rates were determined for selected measurable lesions. Tumor volume doubling time (TDT) in growing tumors or tumor volume halving time (THT) in regressing tumors was measured for multiple lesions. The objective of the study was to correlate tumor growth and/or regression rates with initial tumor size. A total of eight patients with 29 nodules of varying sizes was studied over observation periods the nodules regressed in response to specific chemotherapy. This study suggests that metastatic pulmonary nodules grow or regress at a relatively constant rate that is independent of pretreatment size. Growth and regression rates do not generally fluctuate, although tumor nodules may remain stationary or arrested for variable time periods. The study of tumor kinetics by clinical techniques is relevant to understanding tumor biology and to developing approaches to therapy.

Antineoplastic Agents↗
PubMed1981

An extracellular chemical signal controlling phototactic behavior by D. discoideum slugs.

Developing cells of the cellular slime mold Dictyostelium discoideum release a low molecular weight metabolite (Slug Turning Factor, STF) which, at high uniform concentrations, interferes with phototaxis and thermotaxis by D. discoideum slugs. D. discoideum slugs migrating in darkness are repelled by (exhibit negative chemotaxis to) crude STF exudates. Dose-response curves relating the accuracies of phototaxis and negative chemotaxis to STF concentration indicate that, in both phototaxis and chemotaxis, slugs "measure" the ratios of STF concentrations on their opposite sides. Net STF release is enhanced by light. We propose that light, focused onto the slug's distal side by its convex surface, generates a lateral STF gradient in response to which the slug turns toward the light source.

Chemotactic Factors↗
PubMed1981

A comparison of adriamycin and mAMSA in vitro: cell lethality and SCE studies.

We have compared the actions of ADM and mAMSA in Chinese hamster V79 cells in vitro, using cell survival and sister-chromatid exchange as end-points. Equimolar concentrations of ADM and mAMSA show similar toxicities to exponentially growing cells, and both drugs are less effective in killing chronically hypoxic and plateau-phase cells. Cytotoxicity to thermotolerant cells (41 degrees C for 16 h previously) shows little difference from that for exponential cells. Pre-treating cells with misonidazole under hypoxic conditions reduces the toxicity of both ADM and mAMSA. In addition, an ADM-resistant Chinese hamster cell line, 77A-177, was cross-resistant to mAMSA. Finally, low equimolar sub-toxic doses of both drugs were found to cause similar increases in the levels of sister-chromatid exchanges in V79 cells. These results reveal no major difference in activity between ADM and mAMSA in vitro.

Aminoacridines↗
PubMed1981

Influence of streptozitocin-induced diabetes on glycosyltransferase activities in plasma and renal cortex.

The collagen glucosyltransferase of renal cortex is increased in experimental diabetes and this increased may be partially reversed or prevented by insulin treatment. The absence of any consistent increase in the plasma collagen glucosyltransferase level in diabetes argues against the enzyme's having a significant role in the pathological thickening of capillary basement membranes. The biological significance of the increased renal glucosyltransferase activity in chemically-induced diabetes must therefore remain in doubt but it is possible that the high glucose concentration in the blood simply stimulates the synthesis of new enzyme protein in the kidney.

Animals↗
PubMed1981

Encephalopathy complicating Whipple's disease: failure to respond to antibiotics.

Progressive dementia, vertical ophthalmoplegia, and prominent hypothalamic dysfunction developed in one patient with documented intestinal Whipple's disease despite ongoing antibiotic therapy with intestinal remission. A clinical diagnosis of central nervous Whipple's disease was made on the basis of the patient's presentation. High-dose parenteral penicillin and chloramphenicol were administered for 4 1/2 weeks. There was no improvement in results of daily mental status examination or neuropsychologic testing. Deterioration was noted in the electroencephalographic findings after therapy. Vigorous antibiotic therapy with agents that cross the blood-brain barrier had no immediate beneficial effect. Irreversible neurologic damage or a slow, delayed response may account for this observation.

Adult↗