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Biomedical subjects

J Alexander

Publications and source records attributed to J Alexander.

At least 577 records · Page 32Linked to original sources
PubMed1979

Serial assessment of doxorubicin cardiotoxicity with quantitative radionuclide angiocardiography.

We measured cardiac performance sequentially, using quantitative radionuclide angiocardiography to estimate left ventricular ejection fraction in 55 patients receiving doxorubicin for treatment of cancer. With final doxorubicin dosages greater than 350 mg per square meter, the lowest ejection fraction measured was significantly less than the initial determination. Five patients had severe cardiotoxicity (congestive heart failure). All had an ejection fraction of less than 30 per cent at the time of heart failure, and demonstrated moderate cardiotoxicity (a decline in ejection fraction by at least 15 per cent to a final value of less than 45 per cent) before clinical manifestations. Six patients with moderate toxicity in whom doxorubicin was discontinued did not have heart failure or a further decline in ejection fraction during the follow-up period. Moderate toxicity was continued, but mild toxicity (decline of ejection fraction by greater than 10 per cent, noted in 11 patients) was not well predicted. The assessment of radionuclide left ventricular ejection fraction during doxorubicin therapy may make it possible to avoid congestive heart failure.

Adult↗
PubMed1979

Studies on the interaction of Mycobacterium microti and Mycobacterium lepraemurium with mouse polymorphonuclear leucocytes.

When polymorphonuclear leucocytes (PMN) elicited in mice were infected with Mycobacterium microti or Mycobacterium lepraemurium, phagosome-lysosome fusion occurred with both species. This contrasts with the situation in macrophages where phagosome-lysosome fusion is inhibited by M. microti but not M. lepraemurium. No evidence was found for killing of M. microti or M. lepraemurium when the bacteria were isolated from PMN and their viability tested in cell-free medium or macrophages.

Animals↗
PubMed1979

Adoptive transfer of immunity and suppression by cells and serum in early Mycobacterium lepraemurium infections of mice.

The ability of lymphocytes and serum from mice infected with 10(7) Mycobacterium lepraemurium to adoptively transfer resistance to irradiated (600 rad 60 cobalt) syngeneic mice was studied. Two strains of mice were used: BALB/c mice, which are highly susceptible to moderate cutaneous infections with M. lepraemurium, and C57Bl mice, which are comparatively resistant. In both strains of mice recipients of nylon wool non-adherent spleen cells, and thus T lymphocyte recipients, demonstrated increased resistance to subcutaneous infection with 10(7) M. lepraemurium. Significantly increased susceptibility to infection was noted in the BALB/c recipients of nylon wool adherent spleen cells or serum. No suppressor activity could be demonstrated in the resistant C57Bl strain.

Animals↗
PubMed1979

The effect of selenium on the biliary excretion and organ distribution of mercury in the rat after exposure to methyl mercuric chloride.

The influence of selenium compounds on the biliary excretion and the organ distribution of mercury after injection of methyl mercuric chloride (4 mumol/kg) have been tested. Selenite, seleno-di-N-acetylglycine and seleno-methionine strongly inhibited the biliary excretion of mercury. Selenite even in a molar dose of 1/40 of the methyl mercury dose inhibited the biliary excretion of mercury. The less toxic seleno-di-N-acetylglycine was needed in larger molar doses and did not act as rapidly as selenite. Biliary excreted methyl mercury is known to be partly reabsorbed in the gut. Subsequently a part of it is deposited in the kidneys since drainage of the bile lowered the kidney content of mercury. Rats given selenium compounds in combination with bile drainage showed further reduction of the kidney mercury content than bile duct drainage alone. Thus the demonstrated lowering effect of selenium compounds on the kidney mercury content cannot be completely explained by an inhibition of biliary excretion of mercury. The mercury concentration in the brain was increased by the selenium compounds; the effect being dependent of the selenium dose reaching a maximum at an equimolar selenite--to methyl mercury dose ratio. The mechanisms by which selenium influences the methyl mercury kinetics are discussed.

Animals↗
PubMed1979

The influence of selinium on methyl mercury toxicity in rat hepatoma cells, human embryonic fibroblasts and human lymphocytes in culture.

The effect of methyl mercury and two selenium compounds have been studied in cell cultures. Methyl mercury in concentrations above 1 microM had a pronounced inhibiting effect on the growth of rat Morris hepatoma cells. Glucose and lactate uptake in relation to cell protein was appreciably stimulated by the organic mercury compound. Selenite in low concentration (0.5 microM) and seleno-di-N-acetyl glycine in thousandfold higher concentrations offered considerable protection against these effects of methyl mercury. The same selenite concentration (0.5 microM), which did not affect cell growth, caused an appreciable protection against methyl mercury (6 microM), even if it was added 3 days after methyl mercury. The methyl mercury inhibited the growth of human embryonic fibroblasts and the DNA-synthesis in the human lymphocytes. However, no protective effect of selenite were observed in these cell types. These results suggest that selenium compounds exert their protective effect through cell specific processes rather than by a direct chemical reaction between selenite and methyl mercury.

Animals↗
PubMed1979

The angiographic appearance of the coronary arteries in constrictive pericarditis.

Coronary artery motion was evaluated in normal subjects and patients with constrictive pericarditis (CP), congestive cardiomyopathy, restrictive cardiomyopathy, and coronary artery disease. Seven of the 8 patients with CP had lack of motion of the major coronary arteries. Nine of the 10 patients with congestive cardiomyopathy and a markedly reduced ejection fraction showed normal motion, as did all 4 with restrictive cardiomyopathy and 9 of the 10 with segmental dysfunction due to coronary disease. Pericardial stripping in 5 patients with CP revealed epicardial involvement corresponding to regions of absent motion; one CP patient with normal motion had no epicardial involvement. Lack of motion may suggest CP when the diagnosis is unsuspected, right heart pressures are not obtained, or hemodynamics are atypical. This sign may also help to distinguish CP from restrictive cardiomyopathy, which produces similar hemodynamics.

Adult↗
PubMed1979

Breathing responses of unanesthetized man and guinea pigs to increased transrespiratory pressure.

We compared the breathing responses of unanesthetized men and guinea pigs to externally imposed shifts in lung volume produced by steady pressures applied to the body surface while the mouth remained near atmospheric pressure. Lung inflation caused no consistent or significant changes either in frequency or end-tidal CO2 in the three men. In contrast, during lung inflation the guinea pigs breathed at low frequencies and smaller tidal volumes and showed consistent increases in arterial PCO2 lasting up to 10 min. The changes seen immediately on application of pressure, namely apneic periods followed by breathing in which inspiratory duration was shortened while expiratory duration was substantially increased, indicates that conscious guinea pigs have active inflation reflexes. We concluded that the reflex responses rather than mechanical factors probably account for the underventilation in the guinea pigs and that guinea pigs are not nearly as well equipped as is man to defend gas exchange in the face of nonmetabolic shifts in lung volume.

Animals↗
PubMed1979

Classification of personality disorder.

An interview schedule was used to record the personality traits of 130 psychiatric patients, 65 with a primary clinical diagnosis of personality disorder and 65 with other diagnoses. The results were analysed by factor analysis and three types of cluster analysis. Factor analysis showed a similar structure of personality variables in both groups of patients, supporting the notion that personality disorders differ only in degree from the personalities of other psychiatric patients. Cluster analysis revealed five discrete categories; sociopathic, passive-dependent, anankastic, schizoid and a non-personality-disordered group. Of all the personality-disordered patients 63 per cent fell into the passive-dependent or sociopathic category. The results suggest that the current classification of personality disorder could be simplified.

Humans↗
PubMed1979

Development of delayed hypersensitivity responses in Mycobacterium lepraemurium infections in resistant and susceptible strains of mice.

C57Bl mice are relatively resistant to a moderate subcutaneous infection with Mycobacterium lepraemurium while BALB/c mice are much more susceptible. Cutaneous delayed hypersensitivity reactions which develop in the first 3 weeks of infection were compared in these two strains of mice. Both strains gave a peak of delayed hypersensitivity between 6 and 10 days after infection which was followed by a period of low reactivity before the development, in the third week, of a stable persistent delayed hypersensitivity reaction. There was no difference between the strains in the size at 24 h of the delayed hypersensitivity reaction but the reactions differed in their kinetics. The low resistance strain, BALB/c, gave a Jones-Mote-type of response while the high resistance strain gave a response which could be described as a tuberculin-type reaction.

Animals↗
PubMed1979

Reliability of quantitative strength measurements in children.

In normal children, sex, age, height and weight account for approximately 50% to 70% of variance in the strength scores obtained by quantitative measurements. Although quantitative techniques accurately measure the forces generated by muscle contraction, technical and psychological variables may cause some inconsistency of scores and contribute to the variance observed. To explore the role of these factors, reliability of quantitative strength measurements was examined in children withe normal intelligence and with mild mental retardation using the isokinetic method. Results showed mean score deviations of 5.3% to 5.8% for different muscle groups within the same test. When testing was repeated by the same examiners 7 to 10 days apart, mean score deviations were 7.9% to 9.8% in various muscle groups. Repeated measurements by different examiners 7 to 10 days later yielded 8.7% to 10% mean score deviations for various muscles. Statistical analyses showed that these differences were not significant. Technical and behavioral aspects of test performance are not an important source of inaccuracy and, therefore, cannot contribute significantly to the variance of scores.

Child↗
PubMed1979

Hydrotherapy burn treatment: use of chloramine-T against resistant microorganisms.

The presence of highly resistant gram-negative microogranisms is an area of major concern in the treatment of burned patients. Criteria for the germicide used for hydrotherapy must include effectiveness against the organism, absence of gross side effects, and conservation of human effort and materials. In the program described, these criteria seem to be successfully met. Microbial samplings from numerous patients and repeated examinations of residue taken from equipment demonstrate the elimination of pseudomonas and other gram-negative organisms.

Bacteria↗
PubMed1978

Unusual axonemal doublet arrangements in the flagellum of Leishmania amastigotes.

Studies on the fine structure of Leishmania mexicana, L. enriettii and L. tropica major have revealed several unusual arrangements of microtubules in the flagellar axoneme. The anterior end of the flagellum in these three species was found to contain disarranged axonemal doublets (d) in the absence of the two central singlets(s). Leishmania amastigotes do not use their flagellum as do promastigotes for propulsion, and persistence of the usual 9d and 2s microtubular arrangement may not be necessary.

Animals↗