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Biomedical subjects

S Holm

Publications and source records attributed to S Holm.

At least 253 records · Page 14Linked to original sources

Exposure to acetone. Uptake and elimination in man.

Eight male subjects were exposed to acetone vapor on two occasions for 2 h in the laboratory. On the first occasion they were exposed to about 1,300 mg/m3 during rest and on the second occasion to about 700 mg/m3 during rest (30 min) and exercise at different work loads on a bicycle ergometer (90 min). The total uptake of acetone was 0.6--1.2 g, and the relative uptake was about 45%. The concentration of acetone in alveolar air was 30--40% of that in the inspiratory air, and it was not affected by exposure time or work load. The concentration of acetone in blood increased continuously with increased uptake during exposure, and there was no tendency towards equilibrium. The half-time of acetone in alveolar air as about 4 h, and in venous and arterial blood it was about 6 and 4 h, respectively. The highest concentrations of acetone in urine were measured 3--3.5 h after exposure. The elimination of acetone via the lungs corresponded to about 20% of the total uptake. Only about 1% of the uptake was excreted via urine.

Acetone↗

Gentamicin treatment in severe surgical infections--serum levels, interactions, toxicity and efficacy.

A retrospective and a prospective group of 38 and 20 patients respectively were studied with regard to bacterial strains, clinical effect, toxic side effects and serum concentration of gentamicin in severe surgical infections. A high degree of therapeutic efficacy evaluated as cure or improvement was noted (68 and 75% in the two groups). The serum levels were especially closely checked in the prospective study to keep the gentamicin concentration within the therapeutic range but below toxic levels. This aim was achieved in most cases probably explaining the relatively low incidence of side effects (nephrotoxicity 4 and fungal infection 11 patients). The hazards of gentamicin interactions with drugs like furosemide, penicillins or cephalosporins are discussed.

Adult↗

The role of the synovial fluid and tendon sheath for flexor tendon nutrition. An experimental tracer study on diffusional pathways in dogs.

Radioactive tracers were used to analyse nutritional mechanisms of flexor tendons of dogs during various experimental conditions. The transport and distribution of methyl glucose in the tendon was analysed 15 min after intravenous injection during the following experimental conditions: (1) normal state--rest; (2) passive mobilization of the tendon; (3) active mobilization of the tendon; (4) exclusion of exposure to synovial fluid-preservation of vascular supply; (5) exclusion of vascular supply--preservation of exposure to synovial fluid. The results indicate that active mobilization gives a significant increase in tracer concentration in the volar part of the tendon, while passive mobilization has no such effect. Diffusional pathways from the synovial fluid plays a major role for transport of tracer into the tendon, while the intrinsic vascular system apparently is of no or minor importance in this respect. The main mechanism for solute transport within the tendon is passive diffusion. Transport of sulphate in the volar part follows a similar pattern as in other avascular tissues and the incorporation of sulphate by the cells is low and comparable to that in articular cartilage. The results support our previous hypothesis that the flexor tendon system physiologically corresponds to a joint, and that the synovial fluid plays an important role for flexor tendon nutrition.

Animals↗

Breath concentration as an index of the health risk from benzene. Studies on the accumulation and clearance of inhaled benzene.

Human subjects were exposed to known concentrations of benzene in air for single and repeated daily periods. The breath concentrations measured repeated exposures approached a maximum after 3 d, and this phenomenon indicated that the tissues were approaching saturation under the experimental conditions. The breath concentrations measured after exposure indicated an initial rapid clearance of benzene with a half-time of 2.6 h, followed by a slower phase with a half-time of 24 h. The decay in breath concentration after prolonged occupational exposure appeared to be slower; the difference between the laboratory and industrial studies was, however, not significant. The hygienic significance of these results was discussed, and it was recommended that control measures be employed when a morning breath concentration exceeds 10 ppb.

Atmosphere Exposure Chambers↗

Cefuroxime treatment of urethritis caused by a beta-lactamase-producing strain of Neisseria gonorrhoeae.

A patient who contracted urethritis from a beta-lactamase-producing strain of Neisseria gonorrhoeae was successfully treated with the cephalosporin derivative cefuroxime. As expected, neither cefuroxime nor cefamandole was hydrolysed by plasmid-coded gonococcal beta-lactamase. Cefuroxime ought to be a valuable and efficacious substitute for penicillins in the treatment of gonhorrhoea due to beta-lactamase-producing gonococcal strains.

Adult↗

Biological threshold limits for benzene based on pharmacokinetics of inhaled benzene in man.

Volunteers were exposed to benzene, 2--10 ppm, under controlled conditions up to 6 h a day during five consecutive days. The accumulation and elimination of benzene was measured by determination of benzene concentration -- down to 0.001 ppm -- in exhaled breath. From these observations, a multicompartment model, which approximately describes the kinetics of benzene elimination and accumulation has been designed. On the basis of this model, benzene concentrations in breath, corresponding to exposure levels of benzene, have been estimated. Thus, at a daily exposure to 10 ppm the exhaled benzene concentration in the morning after a day of exposure will not exceed 0.1 ppm.

Aerosols↗

The use of co-trimazine and co-trimoxazole in elderly patients with urinary tract infections.

In a double-blind study geriatric patients received either 410 mg sulphadiazine plus 90 mg trimethoprim (co-trimazine) or 800 mg sulphamethoxazole plus 160 mg trimethoprim (co-trimoxazole) twice daily. The investigation was carried out in order to compare the clinical efficacy and safety of co-trimazine in relation to co-trimoxazole with special emphasis on laboratory data in elderly patients suffering from uncomplicated urinary tract infections. Two to four weeks after start of treatment the original pathogen was eradicated in 80% of the 40 patients that were assessable for the effect of co-trimazine therapy, and in 77.8% of the 39 assessable patients in the co-trimoxazole group. There were no statistically significant differences between the two treatment groups in terms of laboratory data. Both drugs were well tolerated.

Age Factors↗

Effects of low ampicillin concentrations on penicillin sensitive and beta-lactamase producing strains of Neisseria gonorrhoeae.

The effects of therapeutic concentrations of ampicillin on non-beta-lactamase and beta-lactamase producing strains of Neisseria gonorrhoeae were studied. A small but significant fraction of bacteria in a gonococcal population was found to respond in a bacteriostatic rather than a bactericidal way upon ampicillin treatment. In agreement with this was the finding of morphologically unaltered cells in the scanning electron microscope after ampicillin exposure. Ampicillin treatment of beta-lactamase producing gonococci caused a significant release of the enzyme into the surrounding growth media. However, initially all beta-lactamase activity was cellbound. The rate of initial ampicillin hydrolysis was much higher in intact cells of N. gonorrhoeae (TEM-1) than in cells of Escherichia coli K-12 (TEM-1). This suggests that the diffusion rate of ampicillin is much higher in the former organism. The viability of gonococci (TEM-1) was unlike E. coli (TEM-1) affected by low concentrations of ampicillin. However, after complete hydrolysis of ampicillin, viable gonococci (probably bacteriostatic reacting cells) were able to initiate new growth. This heterogeneity of the cell population to penicillin killing is probably one reason why beta-lactamase producing gonococci despite a rather low MIC-value to ampicillin cause infections that are not susceptible to therapy by this agent.

Ampicillin↗

Identification of renal tubular epithelial cells in urine with immunofluorescence.

Rabbits were immunized with human kidney homogenate. The rabbit sera, after absorption with human liver homogenate, showed antibody activity against human kidney, renal pelvis and urinary bladder. The sera were then absorbed with human renal pelvis and urinary bladder mucosa and subsequently showed no antibody activity against urinary bladder or renal pelvis. Immunofluorescence examinations showed fluorescing cells in kidney tubules, but not elsewhere. The finally absorbed antihuman kidney sera were used for indirect immunofluorescence examination of urinary sediments from patients with renal disease. Phase contrast microscopy was used simultaneously. Fluorescence was found in cells which in phase contrast microscopy were judged to be renal tubular cells. Fluorescing cells were often found in casts, but free cells were also seen. Immunofluorescence may thus provide a means of identifying renal tubular cells in urine.

Animals↗

Oxygen tension measurements in the intervertebral disc. A methodological and experimental study.

A polarographic membrane-covered electrode has been used for measurements of oxygen tension in the intervertebral disc. In vitro studies showed that the method measured partial pressures of oxygen with good reproducibility. However, in long continuous experiments, disc matrix adhering to the membrane influenced the readings negatively. The results of in vivo measurements in canine nucleus pulposus showed tensions of the order of 0.53 - 1.06 KPa (4 - 8 mm Hg). No significant variations between different disc levels were found.

Animals↗

Reaction to cold of patients with coronary insufficiency.

Twenty six patients with angina pectoris and coronary insufficiency as judged by an exercise ECG test were examined. About half of the patients had more pronounced ECG changes in a cold room at -15 degrees C than at room temperature. They worked less, their subjective rating of exertion during exercise was higher and the heart performed less work, expressed as the heart rate blood pressure product. The other half of the patients was not much influenced by cold. During an exercise test in the supine position almost all patients got more pronounced ECG changes, worked less and the heart performed less work than in the sitting position. It is suggested that cold exposure as well as a supine body position may to a considerable part exert their effect, i.e. lower the anginal threshold and increase ECG changes, by increasing the central blood volume and the diastolic volume of the left heart and thus ceteres paribus the myocardial oxygen consumption.

Adult↗

[Caudal anaesthesia in obstetrics (author's transl)].

The advantages of caudal anaesthesia in obstetrics far outweigh the few disadvantages. The perinatal mortality of premature infants is reduced under caudal anaesthesia. Breech deliveries are easier under caudal anaesthesia. In these cases regional anaesthesia is considered an obstetrical indication. It is possible to carry out all vaginal and abdominal procedures with this anaesthesia. The elimination of pain during labor and delivery permits a more intensive experience of labor and delivery for the mother under caudal anaesthesia.

Anesthesia, Caudal↗

Binding of aggregated IgG in the presence of fresh serum by group A streptococci producing pharyngeal infection: possible connection with types frequently involved in acute nephritis.

109 streptococcal strains, belonging to diverse serological groups and types, were investigated as regards their capacity to bind IgG aggregates in the presence of fresh serum. Strains capable of such binding were not found in groups B,C,D,E,G,L,M or N. Such binding was restricted to a few types of group A streptococci: the potentially nephritogenic types 2, 6 and 12, and four strains belonging to type M 39, M 46 and M 22 or M 62, the nephritogenic capacity of which is unknown. Two of five strains isolated from patients with acute post-stretococcal glomerulonephritis (AGN) and 19/28 type T 12, SOR-strains, isolated during an epidemic in a kindergarten with associated cases of AGN, were found to bind aggregates. The findings suggest a possible association between capacity to bind aggregates in the presence of serum and the serological types of group A streptococci involved in acute nephritis following pharyngeal infection.

Acute Disease↗