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Biomedical subjects

R F Smith

Publications and source records attributed to R F Smith.

At least 199 records · Page 11Linked to original sources
PubMed1976

Antiarrhythmic effects of a lidocaine congener, tocainide, 2-amino-2',6'-propionoxylidide, in man.

Eight patients with frequent premature ventricular contractions (PVCs) were given single oral doses of 2-amino-2', 6'-propionoxylidide hydrochloride (APX), a lidocaine congener, to investigate the drug's efficacy, toxicity, and pharmacokinetics. Of the 7 patients receiving more than 100 mg, 5 demonstrated at least 60% reduction in PVCs in the 5-hour period following one of the doses; the responsiveness to APX was similar to that observed when intravenous lidocaine was given to the same patients. There were side effects of transient dizziness, lightheadedness, and nausea in 3 patients 20 to 30 min after doses of 400 to 800 mg; slightly smaller doses in 2 of these patients retained efficacy without side effects. There were no effects on arterial blood pressure, heart rate, or the electrocardiogram of normally conducted beats. Laboratory values remained within normal limits, although the hemoglobin level and hematocrit showed a small but significant fall probably related to repeated blood sampling during the study. Drug plasma levels at 1 and 2 hr after administration and the area under the plasma concentration-time curve were proportional to dose, and the drug disappeared with a mean elimination half-life of 14.7 +/- 1.7 hr (mean +/- SD). Plasma levels resulting in suppression of PVCs ranged from 1 to 5 mug/ml. A mean of 39.7 +/- 12.4% of an orally administered dose was recovered unchanged in 48-hr urine collections. Comparison of the present results with those previously obtained after intravenous administration of APX indicates that oral bioavailability of the drug was essentially complete. APX appears to be a promising orally effective antiarrhythmic drug with suitable pharmacokinetic characteristics to warrant studies designed to establish dosage regimens for chronic therapy.

Adult↗
PubMed1976

Immunotherapy with nonviable microbial components.

Structural components of microorganisms have been studied for immunopotentiating effect with the aid of transplantable (line 10) tumors in syngeneic guinea pigs. Microbial components were associated with oil droplets, suspended in Tween-saline, and injected intralesionally. BCG cell walls, given in this way, produced regression and cure of 50-60% of established tumors, as did viable BCG. Lipid extraction markedly reduced the tumor-regressing potency of cell walls, but P3, a trehalose mycolate present in the extract, restored full activity to the cell wall residue. P3 alone was nonsensitizing and had no antitumor activity, but it enhanced the latter property of various other microbial products. For example, the cure rates produced by cell walls of M. tuberculosis, M. bovis, M. phlei, or M. smegmatis were enhanced from 20-60% to as much as 90% by addition of P3. P3 also conferred antitumor activity on products from unrelated microbes, such as cell walls of E. coli, and in combination with endotoxins from rough Re mutant salmonellae, it produced cure rates of up to 93%. These results suggest that P3 is essential to the immunopotentiating activity of mycobacteria and that it may be broadly applicable in immunotherapy of cancer with microbial agents.

Animals↗
PubMed1976

Preliminary studies on the characterization and distribution of Staphylococcus and Micrococcus species on animal skin.

A total of 221 strains of staphylococci and 98 strains of micrococci isolated from the skins of Eastern gray squirrels, Southern flying squirrels, raccoons, opossums, squirrel monkeys, swine, sheep, horses, cattle, and dogs were characterized in a preliminary attempt to resolve their natural relationships and distribution in nature. Staphylococci demonstrating the widest host range included Staphylococcus xylosus and unnamed Staphylococcus sp. 3. Unnamed Staphylococcus sp. 2 was isolated only from sheep, Staphylococcus sp. 4 only from opossums, Staphylococcus sp. 5 only from squirrel monkeys, and Staphylococcus sp. 6 only from swine. The predominant species isolated from human skin, including S. epidermidis, S. hominis, S. haemolyticus, and S. capitis, were either not isolated or only rarely isolated from animal skin. Micrococcus varians was the predominant Micrococcus species isolated from animal skin. M. luteus was only occasionally isolated. M. lylae, M. sedentarius, M. roseus, M. kristinae, and M. nishinomiyaensis, species occasionally isolated from human skin, were not isolated from animal skin.

Animals↗
PubMed1976

Comparative isolation of vaginal yeasts on selective and nonselective media.

The isolation of vaginal yeasts was compared on a selective medium, phosphomolybdic acid agar, and on starch agar, a nonselective differential medium used primarily to isolate Corynebacterium vaginale. The majority of the Candida albicans strains were isolated on starch agar, but the selective medium was required for isolating all yeasts from the greatest number specimens.

Agar↗
PubMed1976

New assay of protective activity of Rocky Mountain spotted fever vaccines.

Areas under the fever curves of guinea pigs inoculated with Rocky Mountain spotted fever vaccine over a restricted dose range and infected with a standardized dose of Rickettsia rickettsii varied linearly with log10 dose of vaccine. A calculator was programmed to plot fever curves and calculate the vaccine dose that reduced the fever of infected animals by 50%.

Animals↗
PubMed1976

Health-related aspects of integrated pest management.

Basic concepts and philosophy of integrated pest management are presented in order to dispel several misconceptions and to provide the necessary background information for discussion of its relationship to the health-related effects of pesticide use. Implications for human health of current pesticide practices in Central America are examined to illustrate major problems associated with the injudicious use of insecticides, i.e., human pesticide poisonings, development of insect resistance, and persistence in the environment. Mitigation of these problems would ideally be achieved through the efforts and cooperation of a multidisciplinary team of scientists and technical people in the medical and agricultural sciences. The dilemma associated with the development of integrated pest control systems in developing countries is discussed. The FAO/UNEP Global Programme was reviewed.

Brazil↗
PubMed1976

Quantitative electrocardiography during extended space flight: the second manned Skylab mission.

To assess the effects of space flight on cardiac electrical properties, vectorcardiograms (VCG) were obtained on the Skylab crew at regular intervals during the 59-d flight (SL3) and during the pre- and postflight periods. The Frank lead system was used and observations were made at rest; during 25%, 50%, and 75% of maximum exercise; during a short pulse of exercise (150 W, 2 min); and after exercise. Data from 47 in-flight tests were analyzed by computer and compared to preflight and postflight values. A statistically significant increase in QRS maximum vector magnitude (all SL3 crewman); and an increase in resting PR interval (all SL3 crewmen) occurred. During exercise, the PR interval did not differ from preflight. Exercise heart rates in flight were same as preflight, but increased in the immediate postflight period. No major changes in QRS, T, or ST vector direction occurred. The scientist pilot had premature ventricular beats sporadically during the flight. This astronaut also had intermittent periods of atrioventricular junctional rhythm throughout the flight. The increase in QRS maximum vector magnitude resembles the electrocardiographic changes associated with athletic conditioning and may be related to increased ventricular volume secondary to centripetal shifts of fluid and/or the in-flight isotonic exercise program. Prolongation of the PR interval at rest with normalization of exercise suggests that there was increased vagal tone or suppressed sympathetic influence during the flight.

Adult↗
PubMed1975

Incidence of yeasts and influence of nystatin on their control in a group of burned children.

The incidence of yeasts in the oral cavity, rectum and urine of a population of 60 children hospitalized for treatment of acute second and third degree burns was approximately the same at the time of their admission as would be expected in healthy subjects. After hospitalization, the incidence of yeasts was reduced in the intestinal tract of acute patients who received nystatin orally but increased in the oral cavity. The majority of 418 yeasts were inhibited in vitro by less than 50 units/ml nystatin and only 6 yeasts were resistant to more than 3.1 mug/ml amphotericin B. The oral cavity appeared to act as a significant reservoir from which yeasts spread to cause or contribute to the deaths of 2 of 5 patients who died during the study.

Adolescent↗
PubMed1975

Secondary arterial repair. The management of late failures in reconstructive arterial surgery.

The incidence and success of secondary operations after reconstructive arterial surgery were studied in a series of 4,247 cases of aneurysmal and occlusive arterial disease. Postoperative complications requiring secondary operations occurred, in order of frequency, as the result of defective healing (including infection), deterioration of the arterial implant, and degenerative arterial changes in the site of surgical intervention. A large variety of surgical techniques were used for correction, such as total replacement, segmental resection and replacement, remote bypass, thrombectomy, and partial excision and reanastomosis. Wth the exception of complications due to infection, the results of repair were good in 60% to 90% of the various categories; only 40% of the infected grafts could be managed without the loss of life or limb. The results appear to justify the trend noted in recent years to a more aggressive use of secondary, salvage operations.

Aneurysm↗
PubMed1975

Bacteremia and postmortem microbiology in burned children.

During a three-year period, Staphylococcus aureus and Pseudomonas aeruginosa were the organisms most commonly isolated from blood cultures of burned children. Microorganisms were considered to contribute to the cause of death in 17 of 20 patients who died from various complications of thermal injuries. Pseudomonas aeruginosa was involved in eight deaths, whereas other Gram-negative bacilli or fungi, or both, were involved in the deaths of the remaining nine patients. The microbiologic examination of cardiac blood and pulmonary tissue correlated reasonably well with clinical and anatomic judgments of cause of death, as well as with the defining of some cases of "terminal sepsis".

Acute Disease↗
PubMed1975

Aortic dissection fifteen years after surgical repair of aortic coarctation.

A case of fatal dissection of the aorta fifteen years following successful surgical repair of aortic coarctation is reported. Histologic secretions of the wall of the proximal aortic segment showed significant thickening and degenerative changes in the media which were not present in the distal aortic segment. This suggests that irreversible structural changes may have occurred prior to surgical repair of the coarctation and supports the view that early surgical repair of this condition is desirable.

Adult↗
PubMed1975

Anastomotic aneurysms after vascular reconstruction: problems of incidence, etiology, and treatment.

To gain a better understanding of the pathogenesis, natural history, therapeutic response, and the potential of prevention of anastomotic aneurysms in general and those following aortofemoral interventions in particular, we have reviewed 4,214 reconstructive vascular operations performed in the past 15 years during which procedures (prosthetic bypass, autogenous vein graft, and endarteriectomy) of fairly uniform technical details have been used. Among these operations representing 9,561 anastomotic sites, we encountered 205 anastomic aneurysms, a per site incidence of 1.7 percent. By far the most common site of occurrence was the femoral artery following Dacron bypass procedures, with a per site incidence of 3.0 percent. The lowest rate of incidence was observed after endarteriectomies, regardless of anatomic location (0.4 percent). The most frequent causative factor was found to be structural deficiency of the parent artery, which accounted for 30.7 percent of the aneurysmal lesions. Other etiological agents, in order of importance, were arterial hypertension, mechanical stress, defect of the graft material, and noninfective healing complications. The therapeutic approach was an aggressive one and only patients with prohibitive operative risks were treated conservatively. In the elective surgical cases the rate of good results was 81.6 percent, with no operative deaths.

Aneurysm↗
PubMed1975

Perceptual discriminability and communication performance in preschool children.

The ability of preschool children to discriminate perceptually among novel forms frequently employed in referential communication tasks is examined. Results suggest that preschool children who are able to discriminate among the forms nevertheless perform poorly on a referential communication task involving these same forms. Asking children to provide names for the forms enhanced their discrimination performance but not their communication performance.

Aptitude↗
PubMed1975

New medium for isolation of Corynebacterium vaginale from genital specimens.

Corynebacterium vaginale was isolated from 48 (23.4%) cervical, vaginal, and urethral swabbings of 205 female outpatients. A new medium modified from peptone starch dextrose agar was used to isolate C. vaginale from most specimens. The new medium contained starch without dextrose with brom cresol purple added. With the exception of certain strains of streptococci, C. vaginale was the only organism isolated from genital specimens that grew and fermented starch on the medium. The new medium provided a rapid means of detecting and isolating C. vaginale compared to other media, and for estimating the relative predominance of the organism in mixed culture. Gram strains were used to detect clue cells in direct smears of clinical material. These cells were detected in only 12 of 48 specimens from which C. vaginale was isolated. Smears on 8 additional specimens contained clue cells but C. vaginale was not isolated. Purple broth base was superior to cystine trypticase agar for confirmatory tests with C. vaginale.

Corynebacterium↗