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Biomedical subjects

V I Iakovleva

Publications and source records attributed to V I Iakovleva.

At least 55 records · Page 3Linked to original sources
PubMedDate not supplied

[Enzymatic synthesis of 3,4-dihydroxyphenyl-L-alanine by free and immobilized Citrobacter freundii cells].

The Citrobacter freundii 62 cells immobilized in PAAG and possessing the tyrosine-phenol-lyase (TPL) activity catalyse the synthesis of 3,4-dihydroxyphenyl-L-alanine (DOPA) from pyrocatechol and ammonium pyruvate. The synthesis of DOPA was studied using both free and immobilized bacterial cells. When the concentration of pyrocatechol is over 0.1 M the TPL activity of the cells is inhibited. The concentration of pyrocatechol can be increased up to 0.3 M by using an equimolar mixture of pyrocatechol and boric acid. The addition of ascorbic acid as an antioxidant results in a lower TPL activity of both free and immobilized bacterial cells.

Acrylic Resins↗
PubMedDate not supplied

[Late development of tumors in the liver of dogs after long-term external gamma-radiation].

Development of tumors in the liver of dogs exposed to gamma-quanta for 3 and 6 years at dose--rates of 0.0006, 0.0017 and 0.0034 Gy/day was studied 1-10 years after termination of the exposure. The results are summarized in this work. Tumors were found in 27 out of 89 dogs. The number of benign and malignant tumors was virtually the same (13 and 14). In the first place were hepatoma, among benign neoplasms (9 out of 13), and liver cancer, among malignant tumors (12 out of 14). Neoplasms were more frequent (32%) in exposed animals than in the controls (19%). Tumors were almost two times more frequent and developed earlier after 6 year- than after-3-year-irradiation.

Animals↗
PubMedDate not supplied

[Fumarate hydratase activity of various Escherichia coli strains].

The fumarate hydratase activity of intact cells was determined for 36 strains of Escherichia coli, receiver from the All-Union Collection of Microorganisms, to reveal a producer of L-malic acid. A research was made to find optimal media for cultivating microorganisms possessing the fumarate hydratase activity. Spectrophotometric and chromatographic methods were chosen to detect malic acid in the complete reaction mixture, which are available for kinetic study of the malic acid synthesis from potassium fumarate.

Chromatography, Gel↗
PubMedDate not supplied

[Formation of neoplasms in dogs after chronic gamma irradiation at a low-intensity dose].

In order to estimate end effects of chronic prolonged gammairradiation of dogs, an exposure of 80 animals to irradiation was terminated and they were followed up closely. Out of 80 animals 30 dogs (1st series) were irradiated for 3 years and 50 dogs (II series) for 6 years. The dogs were exposed to irradiation at doses of 21 to 190 rad per year. Out of the total number of animals 22 dogs died. Post-mortem examinations showed neoformations in 13 animals (7 malignant and 12 benign neoformations). The highest number of tumors developed in dogs of the II series (10 out of 11) one-two years after irradiation (6 malignant tumors--malignant pheochromocytoma of adrenals; malignant adenoma of the hypophysis: polymorphocellular sarcoma of the liver; leucomyosarcoma of the uterus; bladder cancer; breast cancer; and 10 benign tumors--pancreatic adenoma; liver angioma; 2 papillary adenomas of the prostate; 3 renal adenomas; lipoma; polyps of the gall-bladder). Animals of the 1st series displayed 3 neoformations (1 malignant tumor--bladder tumor and 2 benign tumorsliver hepatoma and spleen angioma) 4--5 years after irradiation.

Animals↗
PubMedDate not supplied

[Immobilization of Citrobacter freundii cells with tyrosine phenol-lyase activity by entrapment in natural gels].

A comparative study on immobilization of Citrobacter freundii cells by entrapment in carrageenan, agar, agar-agar, and gelatin gels (5, 10, and 15%) was carried out. Gelatin gels were treated with glutaraldehyde to make them more rigid. As a result, the tyrosine phenol-lyase activity of these samples was less than that of free cells (about 40%). The yield of TP-lyase activity was 40--60% when cells were immobilized in 5% and 7% agar and agar-agar gels. The cells entrapped in carrageenan gels, the concentration of which was varied from 2 to 10%, possessed the highest tyrosine phenol-lyase activity (up to 90%). The efficiency of cell entrapment was high for all the carrier and equal to 70--90%. The plastic strength and swelling of the above gels, as well as the phenol adsorption on the carriers and the release of the bacterial cells from them were studied under the conditions of tyrosine phenol-lyase reaction.

Adsorption↗