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Biomedical subjects

J Michalak

Publications and source records attributed to J Michalak.

At least 19 recordsLinked to original sources
PubMed1995

Exploratory photochemistry of 5-azido-8-alkoxy-substituted psoralens free and bound to DNA.

5-Azido-8-alkoxy psoralens were synthesized. Laser flash photolysis (LFP: XeF, 351 nm, 55 mJ, 17 ns) of the azides in acetonitrile or benzene solution produces the triplet nitrene and a small amount of ketenimine. Laser flash photolysis of the azides in methanol or aqueous solution cleanly produces the triplet nitrene. In aqueous solution containing highly polymerized calf thymus DNA, LFP produces a mixture of triplet nitrene and ketenimine corresponding to photolysis of free and bound psoralen, respectively. The two transients decay slowly but at different rates. Assignment of the transient spectra were secured by matrix EPR and UV-visible spectroscopy. The triplet nitrene lifetime is the same in buffer and in the presence and absence of calf thymus DNA. The results explain why psoralen azides are unable to efficiently nick plasmid DNA pBR322 upon UV activation.

Animals↗
PubMed1995

Protective effect of verapamil on regional myocardial ischaemic injury in dog.

Ischaemic injury was produced in the dog heart by occluding the left anterior descending coronary artery just below the second diagonal branch for 3 h. Verapamil 5.0 mg/kg was injected intravenously 10 min before the occlusion. There was some decrease in ATP and creatine phosphate levels in the hearts of "no drug" animals as compared to sham-operated dogs. Verapamil significantly increase the level of these metabolites. The ATP/ADP ratio decreased from 8.5 +/- 0.60 in hearts from sham-operated dogs to 3.5 +/- 0.30 in the "no drug" group. Verapamil pretreatment resulted in values of the ATP/ADP ratio which were lower than, but not significantly different from, those observed in the control group. In ischaemic mitochondria the calcium content (Ca++) increased significantly as compared to the control and the Verapamil group. A significant increase in free fatty acid content in myocardial membrane preparations was also observed as compared to the sham-operated and the Verapamil group.

Animals↗
PubMed1990

[Surgical treatment of laryngotracheal stenosis].

In the ENT Clinic, Medical Academy, Cracow a joint ENT team accompanied by thoracic surgeon performed the segmentary resection of trachea in three patients with stenosis of the subglottal area and of the upper section of trachea. The connecting surgery of trachea and thyroid cartilage was successful in two patients, but failed in one. Advantages of this method and reason of failure were thoroughly discussed.

Aged↗
PubMed1988

Compensatory mechanisms in erythrocyte lipids in patients with atherosclerosis.

The quantitative composition of phospholipids and fatty acids of erythrocytes was investigated in patients with atherosclerosis. It was stated that the erythrocyte lipids of atherosclerotic patients contained smaller quantities of phosphatidylcholine and phosphatidylinositol, a significantly larger quantity of sphingomyelin, and higher sphingomyelin/phosphatidylcholine and cholesterol/phospholipid ratios. The existence of compensatory changes was stated, which was evident in the reduction of palmitic and stearic acids and the increase of linoleic and eicosatrienoic acids in erythrocyte phospholipids. These changes in fatty acid composition probably cause minimal changes in the membrane fluidity induced by an increased cholesterol/phospholipid and sphingomyelin/phosphatidylcholine ratios. This paper was the first evidence of occurrence of those changes in erythrocytes during spontaneous atherosclerosis in human.

Arteriosclerosis↗
PubMed1987

RNA synthesis in guinea pig peripheral blood lymphocytes and heterophils during sensitization.

The synthesis of RNA in guinea pig leukocytes was investigated during sensitization by the use of tritiated uridine. The increase of the number of RNA-synthetizing heterophils was found in 21st day of sensitization. That was connected with morphological features of heterophils nuclei. Among lymphocytes in 11th day of sensitization the subpopulation of cells intensively synthetizing RNA was observed. The possible role of cells, which synthetize RNA in the process of sensitization is discussed.

Animals↗
PubMed1987

[Lipids of the liver and aorta of rabbits fed with cholesterol before and after surgical exclusion of the terminal segment of the ileum].

The experiments were carried out on 15 rabbits od common breed in 3 groups, K--control, 1--unoperated and 2--operated. The weight of the animals before operation oscillated from 3.8-4 kg. Group 1 was fed with standard food with an addition of 4 g cristal cholesterol and 4 g of pork lard for 21 days. The animals in group 2 were fed similarly. This group was operated with 1/3 bypass of the caudal part of the small intestine. After 3 weeks the rabbits of both groups were killed. For biophysical and pathohistological investigations, sections of the right liver lobe, abdominal aorta and the small intestine were taken. Lipids of the liver and aorta wall were analysed chromatodensitographically. The results were statistically analysed and tabulated. In group 1, three times more lipids were found in the liver and about 2 times more in the aorta wall, than in group K. In group 2, the level of total lipids in the liver and in aorta wall was slightly higher than in the control. It was caused by TG and UF in the liver and by CE and UF in the aorta wall. Microscopic observations in group 1 showed diffused, vast multifocal undegenerative steatosis of the liver and considerable lipids infiltration without atherosclerotic plaques in the aorta wall. In group 2, steatosis of the liver was slight and it did not occur in the aorta wall. Normalization of the composition and distribution of lipids was observed in the liver lobules and aorta wall. Partial by-pass of the small intestine was in atrophy because of inactivity in the presence of a relative multiplication of mucocells.

Animals↗
PubMed1986

The relationship between plasma triglycerides, cholesterol, total lipids and lipid peroxidation products during human atherosclerosis.

Concentrations of plasma triglycerides, cholesterol, total lipids and lipid peroxides in patients with atherosclerotic lesions of peripheral arteries, who were divided into groups according to the extent and intensity of the lesions, were estimated, as well as lipid peroxide levels in the arterial wall. Statistically highly significant increases of the estimated compounds were found in all groups in comparison with the controls. The existence of a positive correlation between the lipid peroxide concentration and other investigated components in plasma and between the lipid peroxide level in plasma and in the arterial wall was found. Possible mechanisms for lipid peroxide involvement in the process of originating atherosclerotic lesions are discussed.

Adult↗
PubMed1986

[Effect of surgical exclusion of the terminal segment of the jejunum on plasma lipid level in rabbits after administration of a cholesterol-fat diet].

The examinations have been performed on 10 native albino rabbits in two experimental groups. Before the experiment the content of a total, free and esterified cholesterol, triglycerides, free fatty acids lipoproteids was determined in heparinised blood plasma. The obtained values served as a control. One group of animals was fed for 21 days a standard food enriched with 4.0 g of cholesterol/day and 4.0 g of lard/day, in the second group of animals a surgical disengagement of a 1/3 distal portion of ileum acc. to the method of Buchwald was performed. After 8 days convalescence the animals were fed for 21 days the same diet as group one. After feeding of atherogenic diet the content of lipid constituents analogical to those in control examinations was determined in blood plasma, and the results were analyzed statistically. It was found that: three weeks overburdening of normal rabbits with cholesterol-fat diet causes a remarkable hiperlipidaemia and an increase of the numerical value of LDL:HDL; operative disengagement of a 1/3 distal portion of ileum before overburdening alimentation enables to maintain normolipidaemia and the numerical value of LDL:HDL ratio on the level approximate to that in controls.

Animals↗
PubMed1985

Adult human thyroid weight.

The weights and dimensions of approximately 1400 normal human thyroid glands were taken at autopsy by the King County Medical Examiner's Office (Seattle, WA) over a two-year period ending in the spring of 1981. The values for thyroid gland weight observed in this data set were compared statistically with those presented by Mochizuki, Mowafy, and Pasternack (New York), with no significant difference being found between the two studies. The two data sets were combined and treated as one providing three distinct adult thyroid gland weights based on age and sex. Male thyroid glands in the age group 20-29 y showed an average of 16.4 g, males 30-69 y of age 18.5 g and females 20-69 y of age 14.4 g. These values are significantly lower than the 20-g (male) and 17-g (female) reference weights given in ICRP Publication 23.

Adult↗
PubMed1985

Evidence of granule discharge in the bone marrow reserve heterophils after acute anaphylactic shock in the guinea pig.

The heterophils in circulating blood and bone marrow were investigated in sensitized guinea pigs after acute anaphylactic shock (AAS) induced by inhalatory antigen challenge. Using histochemical, ultrastructural and in vitro methods evidence was obtained of a granule discharge from bone marrow reserve heterophils (BMRH). The mean number of primary (Biebrich scarlet positive) granules in BMRH decreased from 91 +/- 23 in the control to 74 +/- 23 after AAS. After AAS about 40% of BMRH and numerous circulating heterophils exhibited in the cytoplasm lucent areas which were surrounded by aggregates of granules. Only about 33% of BMRH were not affected by AAS. The rest of the cells showed different stages of granule aggregation and the lucent areas in the cytoplasm. Bone marrow basophils exhibited an early stage of degranulation. Almost 5% of BMRH ingested basophilic granules after AAS. Neither mortality rates in cytotoxicity tests nor antigen binding capacity were different in the experimental and control groups. It is suggested that the heterophils have a regulatory function during the anaphylactic reaction.

Anaphylaxis↗
PubMed1983

The distinction of the white pulp from the red pulp in guinea pig spleen by the use of sequential histoenzymatic methods.

Using the sequential method for revealing of NADH-cytochrome c reductase and other enzymes (acid and alkaline phosphatases, non-specific esterase, peroxidase) or cationic proteins in the same section, the distinct borders between white and red pulp of the guinea pig spleen were delineated. The sequential method enables not only these areas of the spleen to be clearly distinguished, but also the migration of granulocytes from the red to the white pulp. The implications of these findings are discussed in terms of spleen function.

5'-Nucleotidase↗
PubMed1982

[Phagocytosis of Candida albicans L-45 in vitro and evaluation of the changes in the intensity of the reaction to 5'-nucleotidase of neutrophils in men chronically exposed to carbon disulfide].

The phagocytosis capability of the Candida albicans in vitro by neutrophils of 30 men chronically CS2 exposed has been tested, along with the cytoenzymatic reaction to 5 nucleotidase in those neutrophils. The control group consisted of 10 voluntary blood donors. Considerable statistically significant decrease in all the parameters of the pathogenic fungus phagocytosis test has been found. The rate of cells with positive reaction to 5 nucleotidase did not differ significantly from correct values. It may be expected that in the CS2 exposed people neutrophils functioning gets impaired due to direct and indirect effects of carbon disulphide.

5'-Nucleotidase↗