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Biomedical subjects

H Larsen

Publications and source records attributed to H Larsen.

At least 55 records · Page 3Linked to original sources
PubMed1989

Oxygen activation and defence against oxygen toxicity in a psychrophilic Bacteroidaceae.

When suddenly exposed to air the growth of the obligate anaerobic bacterium of the bacteroidaceae type, strain B6, continues for a few hours before coming to a complete stop. When air is shut off soon after growth has ceased, the organism is able to reestablish anaerobic conditions due to an ability to reduce O2, and resumes normal growth after another few hours. The O2 reducing ability of the organism is due to the presence in the cells of a particle-bound NADH oxidase, a soluble NADPH oxidase and a soluble pyruvate oxidase. The two pyridine nucleotide oxidases reduce O2 to H2O2, the pyruvate oxidase reduces O2 to H2O. Catalase and peroxidase were not detected in anaerobically grown cells. Kinetic studies with cell-free extracts showed that the pyruvate oxidase had a considerably greater affinity (smaller Km) for O2 and capacity (higher Vmax) for O2 reduction than the two other oxidases. It is postulated that the pyruvate oxidase acts as a scavenger for O2, leading to the non-toxic reduction product H2O, and thus functions as a defense mechanism against oxygen toxicity when the organism is exposed to aerobic condition.

Air Microbiology↗
PubMed1988

Excretion of mutagens in sweat from humans treated with anti-neoplastic drugs.

Base substitution mutagens were isolated and concentrated from sweat and urine of 7 patients treated with cyclophosphamide and other antineoplastic drugs. These samples were tested in Salmonella typhimurium TA 1535. The perspiration samples were collected under normal physiological conditions for 8 h after medication and urine samples were collected 8 h after medication. The perspiration samples from the patients were significantly more mutagenic than perspiration samples from the 7 control persons. No correlation was found between the mutagenicity of the perspiration samples and the urine samples.

Antineoplastic Agents↗
PubMed1987

Zuclopenthixol and perphenazine in patients with acute psychotic states. A double-blind multicentre study.

Fifty-four patients with acute psychotic states were included in a double-blind multicentre study of zuclopenthixol and perphenazine given orally. Fourteen patients had not received test preparations for a minimum of 3 weeks as stated in the protocol, and were excluded. The remaining 40 patients received the test preparations for 3 to 12 weeks, with an average of 49 days for patients receiving zuclopenthixol and 45 days for patients receiving perphenazine. Clinical evaluations were done at baseline and at weeks 1, 2, 4, 6, 8, and 12 including the CGI, a CPRS subscale for schizophrenia, and the UKU Side Effects Rating Scale. The patients received on average 37 mg zuclopenthixol or 30 mg perphenazine daily. Statistically, significant reductions on the CGI, severity of illness, and on the CPRS (total score) were found for both drugs when comparing baseline with later scores. No significant differences between the drugs were found. It was also impossible to demonstrate a difference in clinical profile between the two drugs on the basis of the single items on the CPRS. Although small differences between the two drugs were found, as regards number and type of side effects, it is concluded that the pattern of side effects was almost identical in the two treatment groups.

Clopenthixol↗
PubMed1987

Stress-tension reduction in the treatment of sexually tortured women--an exploratory study.

Three women who had been tortured and sexually abused during imprisonment as political prisoners during the dictatorship in the Philippines were treated with a nonverbal, manual stress-tension reduction therapy (STRT). All women had difficulty in sexual and social relationships and a series of unspecific complaints such as headache, dizziness, irritability, aggressiveness toward their own children, etc. The therapy is described. A series of four sessions was given each woman, followed by group training. A remarkable improvement was noted, and it is suggested that STRT may be use in other sexological disorders.

Adult↗
PubMed1982

Mutagenic action of methyl 2-cyanoacrylate vapor.

Alkyl 2-cyanoacrylate adhesives were tested for mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1538. Both a normal spot test and a spot test specially designed to test volatile compounds were used. The adhesives were also tested in the plate incorporation assay. These investigations showed that methyl 2-cyanoacrylate adhesives are mutagenic in strain TA100. The spot test for volatile compounds showed that it is the vapors from the methyl 2-cyanoacrylate monomer that are responsible for the mutagenic effect. One can conclude that working with methyl 2-cyanoacrylate adhesives entails exposure to vapors with a mutagenic effect and may therefore pose a carcinogenic hazard. Because the adhesives are used in industry, their mutagenic effect has a special importance in work environment.

Cyanoacrylates↗
PubMed1981

Mechanical testing of trabecular bone in knee replacement.

To measure the strength of the juxta-articular trabecular bone in knee replacement, an osteopenetrometer was developed. The principle of its function is tha a needle penetrates the bony tissue and during this penetration the pressure on and the displacement of the needle is registered. The instrument was tested on cadaveric specimens of the proximal tibia. Good agreement was found between the osteopenetrometer findings in 18 cases and compression tests on the same bony structure. Forty-five measurements at different sites of the tibial resection surface revealed that the force needed for the penetration varied according to a pattern known from the determination of the elasticity modulus and ultimate compressive strength of bone in the same area. Histological examination of the penetration canals in the bone disclosed only sparse upsetting of bone. Curves from corresponding bone proved to reflect, in height as well as shape, the morphology of the skeletal structure. The osteopenetrometer appears to be applicable fo objectively assessing the solidity of trabecular bone during the operation. Thereby it is possible, in each individual case, to form a basis for more varied planning of the postoperative treatment programme.

Biomechanical Phenomena↗