Effect of intermittent normobaric hypoxia on kinetic properties of mitochondrial enzymes.

We studied the effect of intermittent normobaric hypoxia on the formation of adaptive signs and state of mitochondrial enzymes in the cerebral cortex of rats with different resistance to hypoxia. Kinetic parameters for mitochondrial enzymes in the substrate region of the respiratory chain of the cerebral cortex underwent various changes in low resistant and highly resistant rats over the first 2 h after 1-h intermittent normobaric hypoxia. Low resistant animals were characterized by more effective functioning of rotenone-sensitive NADH-cytochrome C reductase and succinate-cytochrome C reductase under conditions of increased reduction status of the cell. These features correlated with the increase in the general resistance of animals. Significant changes in kinetic properties of mitochondrial enzymes and signs of the development of resistance were not found in highly resistant rats. Reciprocal relations between mitochondrial enzyme complexes in the substrate region of the respiratory chain probably play a role of the signal regulatory mechanism, which mediates tissue-specific and general resistance of rats under conditions of intermittent normobaric hypoxia. These effects did not depend on oxygenation of the inhaled gas mixture during the inter-hypoxic period.

[Intersensory correlations in diabetic neuropathy during adaptation to intervalic normobaric hypoxia]. / Mezhsensornye vzaimootnosheniia pri diabeticheskoi neiropatii v protsesse adaptatsii k interval'noi normobaricheskoi gipoksii.

The state of vibration sensitivity and of gustatory perception as well as the influence of interval hypoxic training on these indices were estimated in 21 patients with insulin-independent diabetes mellitus (IIDM) without neuropathic manifestations, in 21 analogous patients with neuropathic manifestations and in 16 individuals with neuropathies of nondiabetic genesis. The improvement of indices studied was observed in patients with neuropathies. Interval hypoxic training may be recommended for the treatment of distal neuropathies including the patients with IIDM in the state of compensation.

Loss of an estrogen receptor isoform (ER alpha delta 3) in breast cancer and the consequences of its reexpression: interference with estrogen-stimulated properties of malignant transformation.

Comparison of mRNA ratios of a non-DNA-binding estrogen receptor (ER(alpha)) isoform, missing exon 3 (ER(alpha)delta3), to the full-length ER(alpha), in normal breast epithelium to that in primary breast cancers and breast cancer cell lines revealed a 30-fold reduction of this ratio in cancer cells (P < 0.0001). To test what functions may have been affected by the loss of ER(alpha)delta3, stable clones of MCF-7 cells expressing ectopic ER(alpha)delta3 protein, at the range of physiological ER(alpha), were generated. In vector-transfected controls the ER(alpha)delta3-mRNA and protein were less than 10% while in the ER(alpha)delta3-expressing clones, ER(alpha)delta3-mRNA and protein ranged from 36-76% of the total ER(alpha). Estrogen (E2) stimulated the expression of pS2-mRNA in pMV7 vector control cells, but the stimulation was reduced by up to 93% in ER(alpha)delta3-expressing clones. In addition, several properties associated with the transformed phenotype were also strongly affected when ER(alpha)delta3 protein was reexpressed. Compared with vector-transfected control cells, the saturation density of the ER(alpha)delta3-expressing clones was reduced by 50-68%, while their exponential growth rate was only slightly (14.5 +/- 5%) lower. The in vivo invasiveness of the ER(alpha)delta3-expressing cells was significantly reduced (P = 0.007) by up to 79%. E2 stimulated anchorage-independent growth of the pMV7 vector control cells, but reduced it to below baseline levels in ER(alpha)delta3 clones. The reduction of the pS2 response to E2 in the ER(alpha)delta3-expressing clones and the E2 block of anchorage-independent growth to below baseline were more pronounced than expected from the dominant negative function of ER(alpha)delta3. These observations suggest that E2 may activate an additional ER(alpha)delta3-dependent inhibitory pathway. The drastic reduction of ER(alpha)delta3 to ER(alpha) ratio in breast cancer, and the fact that when present in breast cancer cells this isoform leads to a suppression, rather than enhancement, of the transformed phenotype by E2 suggests that the regulation of ER(alpha)-mRNA splicing may need to be altered for the breast carcinogenesis to proceed.

Myofibroblasts differentiate from fibroblasts when plated at low density.

Myofibroblasts, defined by their expression of smooth muscle alpha-actin, appear at corneal and dermal incisions and promote wound contraction. We report here that cultured fibroblasts differentiate into myofibroblasts by a cell density-dependent mechanism. Fibroblasts seeded at low density (5 cells per mm2) produced a cell culture population consisting of 70-80% myofibroblasts, 5-7 days after seeding. In contrast, fibroblasts seeded at high density (500 cells per mm2) produced cultures with only 5-10% myofibroblasts. When the myofibroblast-enriched cultures were subsequently passaged at high density, the smooth muscle alpha-actin phenotype was lost within 3 days. Furthermore, initially 60% of the low density-cultured cells incorporated BrdUrd compared to 30% of cells passaged at high density. Media from myofibroblast-enriched cultures had more latent and active transforming growth factor beta (TGF-beta) than did media from fibroblast-enriched cultures. Although there was a trend towards increased numbers of myofibroblasts after addition of exogenous TGF-beta, the results did not reach statistical significance. We conclude that myofibroblast differentiation can be induced in fibroblasts by plating at low density. We propose a cell density-dependent model of myofibroblast differentiation during wounding and healing in which at least two factors interact: loss of cell contact and the presence of TGF-beta.

Estrogen receptor messenger RNA expression in human benign prostatic hyperplasia: detection, localization, and modulation with a long-acting gonadotropin-releasing hormone agonist.

We have analyzed human benign prostatic hyperplastic (BPH) tissue derived from eight radical prostatectomy specimens from patients with prostate cancer for the expression of the estrogen receptor (ER) messenger RNA. Four of the eight patients received a long-acting gonadotropin-releasing hormone agonist (GnRHa) for 4 months prior to surgery. An RNase protection assay utilizing six riboprobes spanning most of the ER protein-coding sequences demonstrated expression of the ER mRNA in human BPH tissue. A comparison of ER mRNA expression in four patients who had received 4 months pretreatment with the GnRHa vs. the four untreated patients suggested that there is upregulation of ER mRNA expression with the GnRHa treatment. The combined techniques of in situ hybridization and immunocytochemistry localized the ER mRNA expression to the prostatic basal epithelial cells and stroma. We conclude that ER mRNA is expressed in human BPH tissue and that this expression is modulated by treatment with a long-acting GnRH agonist.