Biotechnological approaches to creation of hypoxia and anoxia tolerant plants.

The present work provides results of a number of biotechnological studies aimed at creating cell lines and entire plants resistant to anaerobic stress. Developed biotechnological approaches were based on earlier fundamental researches into anaerobic stress in plants, so "Introduction" briefly covers the importance of the problem and focuses on works considering two main strategies of plants adaptation to anaerobic stress. Those are adaptation at molecular level where key factor is anaerobic metabolism of energy (true tolerance) and adaptation of the entire plant via formation of aerenchyma and facilitated transportation of oxygen (apparent tolerance). Thus, sugarcane and wheat cells resistant to anaerobic stress were obtained through consecutive in vitro selection under conditions of anoxia and absence of exogenous carbohydrates. Tolerant wheat cells were used to regenerate entire plants of higher resistance to root anaerobiosis. It has been demonstrated that cells tolerance to anoxia is significantly supported by their ability to utilize exogenous nitrate. Cells tolerance established itself at the genetic level and was inherited by further generations. Apart from that, other successful attempts to increase tolerance of plants to anaerobic stress by means of stimulation of glycolysis and overexpression of genes responsible for cytokinin synthesis and programmed cell death are also discussed. The presented data proved the notion of two main strategies of plants adaptation to anaerobic stress proposed earlier on the base of fundamental studies.

Cooperative antitumor effect of endothelial-monocyte activating polypeptide II and flutamide on human prostate cancer xenografts.

UNLABELLED: Recombinant cytokine-like endothelial monocyte-activating polypeptide II (EMAP II) and antiandrogen flutamide target different mechanisms of growth of androgen-dependent prostate cancer (PC). The aim of this study was to clarify whether combined treatment with EMAP II and flutamide is more effective than monotherapy with regard to retardation of PC progression. MATERIALS AND METHODS: Antitumor effects of EMAP II (10 µg/kg b.w./d, s.c., 3d), or flutamide (10 mg/kg b.w./d, per os, 3d), or their combination were studied in CBA male mice bearing human androgen-dependent PC xenografts for 7 days. Androgen-dependent phenotype of the tumors was verified in preliminary castrated mice. The xenografts were weighed and underwent a histopathologic examination. The results were compared with those of non-treated mice. RESULTS: EMAP II and flutamide used separately inhibited growth of the xenografts by 74% and 53% respectively. Both drugs caused destructive changes in malignant epithelial cells along with leukocyte infiltration of the tumor. Combined treatment inhibited tumor growth by 85%, and was more effective than monotherapy with regard to morphological changes. CONCLUSIONS: This study demonstrates cooperative inhibitory effect of EMAP II and flutamide on growth and morphology of human PC xenografts that could represent a new modality of palliative treatment of this disease.

Antitumor effect of endothelial monocyte-activating polypeptide-II on human prostate adenocarcinoma in mouse xenograft model.

UNLABELLED: Endothelial monocyte-activating polypeptide-II (EMAP-II) is a novel proinflammatory cytokine with anti-angiogenic properties. The aim of this work was to evaluate in vivo antitumor activity of EMAP-II in growing human prostate adenocarcinoma xenograft mouse model. MATERIALS AND METHODS: Recombinant human EMAP-II was expressed in Escherichia coli and purified after cleavage with enterokinase (EMAP-II e). EMAP-II preparations were injected to CBA mice bearing subrenal capsule xenografts of human prostate adenocarcinoma. After 3-days treatment, the xenografts were isolated and weighed, then the transplants exposed to EMAP II e (100 or 200 microg/kg b. w.) were examined histologically. RESULTS: EMAP-II administered daily at a dose of 100 or 200 microg/kg b. w. caused striking retardation of local tumor progression as compared to the controls. Low dose (10 microg/kg) was effective in some cases. CONCLUSION: EMAP II exhibits significant antitumor activity in vivo in human prostate adenocarcinoma xenografts in mouse model.

Neuroendocrine mechanisms of development of experimental hyperandrogen-induced anovulation.

An experimental model of hyperandrogen-induced anovulatory infertility (s.c. implantation of Silastic capsules containing testosterone into adult female rats) was used to study morphological, hormonal, and biochemical measures characterizing the state of the hypothalamo-hypophyseal-ovarian system. Impairments in functional androgen metabolism in the hypothalamus were seen, with decreases in the Luliberin sensitivity of the hypophysis, changes in the structure of estral cycles, and morphological changes in the ovaries; these findings are evidence for neuroendocrine disturbances in the control of ovulation. Flutamide, an experimental antiandrogen, led to partial normalization of the hormonal, biochemical, and morphological characteristics, as well as to recovery of fertility in females with anovulatory infertility.

Early and long-term neuroendocrine effects of prenatal stress in male and female rats.

The effects of maternal stress, termed prenatal stress (PNS) on the neuroendocrine regulation of reproduction and the stress reactivity of offspring were studied in rats. PNS prevented the formation of sexual dimorphism in catecholamine levels, aromatase activity, and androgen 5alpha-reductase activity in the preoptic area of the brain and the mediobasal hypothalamus in 10-day-old rats. The morphological correlate of the functional lesions induced by PNS consisted of the elimination of gender-related differences in the volumes of neuron nuclei in the suprachiasmatic nucleus. Prenatal stress altered the stress and adrenergic reactivities of the hypothalamo-hypophyseal-adrenal system in mature males and females. The long-term effects of PNS were regarded as a consequence of the disruption of the hormone-neurotransmitter imprinting of the neuroendocrine system.

Endocrine mechanisms of suppressive effect of low dose estrogen-antiandrogen treatment on androgen-dependent organs of male rats.

The effects of low doses of hexestrol (Hex) (2-40 micrograms/kg bw) and flutamide (FI) (10 mg/kg bw) on some endocrine mechanisms in mature intact male rats are described in the present paper. It has been shown that each preparation, administered separately for 10 days, induced a moderate decrease in the weight of the ventral prostate (VP), anterior prostate lobe or coagulating gland (CG) and seminal vesicles (SV), in the DNA content and number of cells in the VP. 5 alpha-reductase activity was also decreased; the epithelium secretory activity of the VP was suppressed. After combined FI (10 mg/kg bw) and Hex (40 micrograms/kg bw) the following castration-like effects were observed: an abrupt fall in the weight of the accessory sexual glands, a decrease of DNA level and cell number in the VP as well as a suppression of the production of 5 alpha-reductase metabolites in this structure. Histologically, a marked degenerative changes in the VP secretory epithelium was observed; on the contrary an hyperplasia of connective and smooth muscle cells was evident. When FI alone was administered to rat, the above-mentioned changes were accompanied by a pronounced elevation of plasma bio-LH and testosterone (T) levels, also an increase of testicular delta 5-3 beta-hydroxysteroid dehydrogenase activity was observed. On the contrary, when Hex was administered alone or in combination with FI, bio-LH and T levels and enzyme activity decreased. We conclude that Hex administration in low doses, in combination with FI, could be an alternative method for a complete androgen blockade of the accessory sexual glands.