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Biomedical subjects

M A Furman

Publications and source records attributed to M A Furman.

At least 19 recordsLinked to original sources

Measurement of dermal collagen synthesis rate in vivo in humans.

Accumulation of collagen produces organ dysfunction in many pathological conditions. We measured the fractional synthesis rate (FSR) of dermal collagen in five human volunteers from the increment of [13C]proline in detergent-soluble dermal collagen hydroxylated to hydroxyproline during a continuous infusion of L-[1-13C]proline. In these and eight other volunteers, we measured [13C]proline enrichment in skin aminoacyl-tRNA, skin tissue fluid amino acid, and plasma. The prolyl-[13C]tRNA enrichment was one-half that in tissue fluid proline and more than threefold less than in plasma. The FSR of dermal collagen was 0.076 +/- 0.063%/h (mean +/- SD), similar to previously reported rates for skeletal muscle contractile proteins and substantially slower than hepatically derived circulating proteins such as albumin or fibrinogen. We conclude that the FSR of human dermal collagen resembles that of other human proteins considered to display slow turnover. The current method for its measurement may be used to determine the regulation of collagen synthesis in other organs and disease states.

Collagen↗

[The role of nitrites in carcinogenesis].

Data from literature as well as the results of the author's investigations on the genotoxic and carcinogenic effects of sodium nitrite (SN) are presented. Carcinogenicity of SN detected in animal experiments proved to be connected with the formation of nitroso compounds from endogenous nitrosable precursors. Sodium nitrite possessed the transforming and promoting effects in the cell cultures as well as the mutagenic effects in the bacterial systems where predominant effect of SN as compared with N-nitrosodimethylamine (NDMA) was registered. The prolonged pretreatment with SN amplified the liver DNA damage in rats in case of NDMA endogenous synthesis.

Animals↗

[Damage to the liver DNA of rats during the endogenous synthesis of N-nitrosodimethylamine].

The damage of liver DNA formation during endogenic synthesis of N-nitrosodimethylamine (NDMA) have been studied after introduction of its precursors, dimethylamine, amidopyrine and sodium nitrite, into the rat stomach. A combined administration of various doses of dimethylamine and nitrite increased the amount of single-strand DNA from 3.0 to 11.3%. The maximum DNA damage after administration of the precursors was observed after 24 h, and after 48 h it decreased to the control level. Pretreatment of rats with dimethylamine or nitrite increased the DNA damage induced by NDMA formation (37.4% and 41.6%, respectively).

Alkylation↗

[Immunological diagnosis of Mycoplasma pneumonias].

A complex of immunological cell tests with M. pneumoniae antigen (the lymphocyte blast-cell transformation test, the allergic neutrophil alteration test) was carried out in order to establish the correlation between the results of positive seroconversion and the sepcific immunological reactivity of lymphoid cells in pneumonia patients. Mycoplasmic cutireactive allergen, when used for the accelerated diagnosis of mycoplasmic pneumonia in humans, was shown to be specific and safe. Cuti-allergic tests with mycoplasmic allergen allowed to diagnose mycoplasmic pneumonia at early stages (beginning from days 5--7), which ensures the possibility of indicating etiotropic treatment to patients in due time.

Allergens↗

Cyclic AMP and adenyl cyclase in brain tumors.

Some of the regulatory mechanisms of cyclic adenosine monophosphate (AMP) production in human brain tumors were investigated by assessing both cyclic AMP levels and adenyl cyclase activity. A large disparity was found between the levels of cyclic AMP of normal brain and brain-tumor tissue. Cyclic AMP levels were much lower in brain tumors (25.8 pmoles (picomoles)/mg protein) than in normal brain (98.8 pmoles/mg protein). These studies also show that the abnormally low levels of cyclic AMP in tumors parallel those of adenyl cyclase. The mean adenyl cyclase activity of brain tissue was found to be 111.0 pmoles of cyclic AMP/min/mg protein, while that of the tumor was only 23.0 pmoles/min/mg protein. Levels of cyclic AMP and adenyl cyclase activity were inversely related to the degree of malignancy. Attempts to stimulate adenyl cyclase in homogenates of human brain and brain tumors resulted in a similar response in both tissues. Norepinephrone was the most effective stimulant and produced a two- to threefold increase in cyclic AMP production, while histamine had no effect. It is concluded that one of the factors governing tumor growth may be a defect in the adenyl cyclase system.

Adenylyl Cyclases↗

[The significance of developmental anomalies of the thyroid cartilage for the practice of forensic medical expertise].

The authors discuss developmental abnormalities of the thyroid cartilage and its injuries in blunt injuries of the neck. Basing on two cases, they describe developmental abnormalities (no joining between the superior horn and the lamina or complete absence of one of the superior horns) that during autopsies were considered, to be resultant from injuries.

Adult↗

The carcinogenic danger of nitrie pollution of the environment.

Presented are the literature data as well as the results of our own investigations on the genotoxic and carcinogenic effects of sodium nitrite (SN). The carcinogenicity of SN detected in animal experiments appears to be related to the formation of nitroso compounds from endogenous nitrosable precursors. Sodium nitrite possesses transforming and promoting effects in cell cultures, as well as mutagenic effects in the bacterial systems, where the predominant effect of SN was compared to that of N-nitrosodimethylamine (NDMA). Prolonged pretreatment with SN amplifies the liver DNA damage in rats in case of NDMA endogenous synthesis.

Aminopyrine↗