Hyperosmotic stimuli induces recruitment of aquaporin-1 to plasma membrane in cultured rat peritoneal mesothelial cells.

Aquaporin-1 (AQP-1) has been reported to play an important role in peritoneal dialysis. To determine the precise mechanism involved, we used cultured rat peritoneal mesothelial cells (RPMCs) to examine the translocation of AQP-1 to the plasma membrane induced by hyperosmotic stimuli. Cultured RPMCs obtained from male Sprague-Dawley rats were incubated at room temperature in Dulbecco modified Eagle medium/F12 (DMEM/F12) with and without glucose or mannitol as the hyperosmotic stimulus. The plasma membrane was then extracted by the Percoll gradient method. Finally, the abundance AQP-1 molecules in the membrane fraction was determined by Western blot analysis. Significant enhancement of AQP-1 abundance (p < 0.05) was observed within 2.5 minutes of the addition of 5% glucose to the medium. The increase was sustained in its abundance through 15 minutes. Abundance of AQP-1 was also increased (p < 0.05) by the addition of 5% mannitol. These results suggest that hyperosmotic stimuli could generate increased AQP-1 abundance in the plasma membrane by translocation of AQP-1 protein from recycling endosomes or early endosomes to the plasma membrane, rather than by protein synthesis via newly expressed mRNA. The latter mechanism would be expected to take more time.

Mechanism of sodium load-induced hypertension in non-insulin dependent diabetes mellitus model rats: defective dopaminergic system to inhibit Na-K-ATPase activity in renal epithelial cells.

Obesity-related non-insulin dependent diabetes mellitus (NIDDM) is frequently accompanied by hypertension. The present study was designed to clarify this mechanism. We first determined the blood pressure in male Wistar fatty rats (WFR), one of the NIDDM model rats, and in Wistar lean rats (WLR) as the control, with a normal (0.7% NaCl) or high (7% NaCl) salt diet. We observed no difference in systolic and mean blood pressures between WFR and WLR. WFR, however, became extremely hypertensive as a result of ingesting the high salt diet. We next investigated the mechanism for sodium sensitivity in WFR. Although the urinary excretion of dopamine (DA), a potent natriuretic factor, which reflects the ability for renal DA production, was preserved in WFR, the sodium balance with the high salt diet was positive. Moreover, Na-K-ATPase activity in isolated proximal convoluted tubules (PCT) from WFR with a normal salt diet was significantly (p<0.05) higher than that from WLR. A high salt load produced a significant (p<0.05) decrease in Na-K-ATPase activity in WLR but not in WFR. Similarly, Na-K-ATPase activity in WLR with a normal salt diet was significantly (p<0.05) inhibited by DA (10(-5) M), but this was not true in WFR. Furthermore, urinary excretion of norepinephrine in WFR with a high salt diet was the highest among all the groups. These results indicate that WFR tend to develop salt-sensitive hypertension that could be caused by the excessive sodium retention occurring as the results of a defective dopaminergic system in the kidney that fails to inhibit Na-K-ATPase activity. Augmentation of the renal sympathetic nervous system may play some role in this setting.

[A case of Fabry's disease with chronic renal failure].

Fabry's disease is a genetic disorder caused by the absence of alpha-galactosidase (alpha-Gal), the gene of which is carried on the long arm of the X chromosome. This enzymatic defect leads to an accumulation of glycosphingolipids in the plasma and lysosomes of endothelial, perithelial, and smooth muscle cells, especially involving those of the cardiovascular, renal and cerebrovascular systems. We report one male case of Fabry's disease with renal deterioration. A 36-year-old man who was a classic case with acroparesthesia, angiokeratoma, and hypohidrosis from 10 years of age, was diagnosed to be a hemizygote of Fabry's disease at 27 years as a result of severe decreased alpha-Gal activity of his peripheral white blood cells. This patient was found to have a point mutation of a G to A transition in exon 1. In May, 1989, he was reported to have proteinuria with normal renal function and admitted to our hospital due to renal deterioration in September, 1993. Laboratory examinations revealed a serum urea nitrogen of 65 mg/dl and creatinine value of 6.9 mg/dl. Urinary protein excretion was 3.9 g/day and urinary sugar was negative. On the renal biopsy specimens, light microscopic examinations revealed multiple sclerosing and collaptic lesions in glomeruli without severe tubulo-interstitial damage, but with stenotic change of the small arteries and arterioles. Electron microscopic examinations revealed a large number of electron dense deposits in the tubules. We diagnosed this case as Fabry's disease with chronic renal failure, however the pathogenesis of this renal progressive deterioration remained obscure. In this case, degenerative changes in the renal vessels due to Fabry's disease may be associated with rapid deterioration in renal function.

Glucose decreases Na+,K+-ATPase activity in pancreatic beta-cells. An effect mediated via Ca2+-independent phospholipase A2 and protein kinase C-dependent phosphorylation of the alpha-subunit.

In the pancreatic beta-cell, glucose-induced membrane depolarization promotes opening of voltage-gated L-type Ca2+ channels, an increase in cytoplasmic free Ca2+ concentration ([Ca2+]i), and exocytosis of insulin. Inhibition of Na+,K+-ATPase activity by ouabain leads to beta-cell membrane depolarization and Ca2+ influx. Because glucose-induced beta-cell membrane depolarization cannot be attributed solely to closure of ATP-regulated K+ channels, we investigated whether glucose regulates other transport proteins, such as the Na+,K+-ATPase. Glucose inhibited Na+,K+-ATPase activity in single pancreatic islets and intact beta-cells. This effect was reversible and required glucose metabolism. The inhibitory action of glucose was blocked by pretreatment of the islets with a selective inhibitor of a Ca2+-independent phospholipase A2. Arachidonic acid, the hydrolytic product of this phospholipase A2, also inhibited Na+, K+-ATPase activity. This effect, like that of glucose, was blocked by nordihydroguaiaretic acid, a selective inhibitor of the lipooxygenase metabolic pathway, but not by inhibitors of the cyclooxygenase or cytochrome P450-monooxygenase pathways. The lipooxygenase product 12(S)-HETE (12-S-hydroxyeicosatetranoic acid) inhibited Na+,K+-ATPase activity, and this effect, as well as that of glucose, was blocked by bisindolylmaleimide, a specific protein kinase C inhibitor. Moreover, glucose increased the state of alpha-subunit phosphorylation by a protein kinase C-dependent process. These results demonstrate that glucose inhibits Na+, K+-ATPase activity in beta-cells by activating a distinct intracellular signaling network. Inhibition of Na+,K+-ATPase activity may thus be part of the mechanisms whereby glucose promotes membrane depolarization, an increase in [Ca2+]i, and thereby insulin secretion in the pancreatic beta-cell.

[Intra-arterial infusion chemotherapy for recurrent cervical lymph nodes after surgery in esophageal cancer].

We attempted intra-arterial infusion chemotherapy using a reservoir system in recurrent cervical lymph nodes after surgery for esophageal cancer, and obtained favorable results. Intra-arterial infusion chemotherapy (75 mg of cisplatin and 5 mg of peplomycin) was performed using a reservoir system connected with a catheter inserted into the left subclavian artery, because recurrent lymph nodes developed in the left supraclavicular fossa. The therapy was effective for 6 months and the quality of life was improved without side effects.

Intersite variation of estrogen receptors in human breast cancers and response to endocrine therapy. Which section of a large tumor is the best for estrogen receptor assay?

Estrogen receptor (ER) assays were performed by sucrose gradient centrifugation method at multiple sites in large breast cancers. Intersite variation of ER in a tumor was observed in 24 out of 35 cases. 16 tumors with relatively low ER levels showed different ER status with multiple assays. The results suggest that an assay performed on a small random part of a large tumor may not yield the true ER status. ER value at the largest cross-section was almost the same as the average ER values in each tumor. In addition, 21 cases were examined in relation to ER values at multiple sites in the large tumors and response to endocrine therapy. As the ER value at the largest cross-section was highly correlated with the therapeutic response to endocrine therapy of breast cancer, it would represent true ER status and level. The results suggest that the ER assay at the largest cross-section of a large tumor is an appropriate method to predict response to endocrine therapy.

Antitumor effects of a nonsteroidal aromatase inhibitor (CGS 16949A) on 7, 12-dimethylbenz[alpha]anthracene-induced mammary tumors in rats.

The effects of a nonsteroidal aromatase inhibitor, CGS 16949A, on female Sprague-Dawley (SD) rats with 7, 12-dimethylbenz[alpha]anthracene (DMBA)-induced mammary cancers were examined in relation to estrogen receptors (ER). Rat tumor sizes in each treated group were significantly smaller (P less than 0.05) and rat body weights in most treated groups were significantly increased (P less than 0.05) compared to those in the control group (no treatment) at all measurement points during treatment. Rat uterine weights in each treated group decreased significantly compared with those in the control group (P less than 0.05). There was no significant difference between ER-positive and ER-negative groups in tumor size, body weight or uterine weight. At increased doses of CGS 16949A in the experiment, further increases in testosterone levels and further decreases in estradiol levels were shown to occur. The results suggest the mechanisms of CGS 16949A action not to be influenced by the presence or absence of ER, but to be due to its potent aromatase inhibition of the conversion of androgens to estrogens.

Effects of sequential and combined immuno-endocrine therapies using OK-432 (Picibanil) and tamoxifen on the growth of 7,12-dimethylbenz [alpha] anthracene-induced rat mammary carcinoma.

Effects of sequential and combined immuno-endocrine therapies using OK-432 (Picibanil) and tamoxifen (TAM) on the growth of 7,12-dimethylbenz [alpha] anthracene (DMBA)-induced carcinoma were examined in 128 female Sprague-Dawley (SD) rats. The rats were divided into six groups: control (no treatment), tamoxifen, OK-432, simultaneous immuno-endocrine OK-432 and TAM (OK-432 + TAM) therapy, two types of sequential immuno-endocrine therapy of the OK-432 and TAM groups [OK-432 (1 wk)----TAM (4 wk) and OK-432 (2 wk)----TAM (3 wk)]. Each group was treated consecutively for five weeks. The response rates in the TAM alone group, the [OK-432 (1 wk)----TAM (4 wk)] group and the [OK-432 + TAM (5 wk)] group were significantly higher than in the control group. When the results among the treated groups were compared, the response rate in the [OK-432 (1 wk)----TAM (4 wk)] group was significantly higher than in the OK-432 alone or TAM alone groups. The response rate in the [OK-432 (2 wk)----TAM (3 wk)] group, however, was lower than in the TAM alone group. The response rate in the OK-432 + TAM group was, moreover, not significantly superior to that in the TAM alone group. These results suggest OK-432 not to potentiate the antitumor effect of TAM since the response rate of the combined OK-432/TAM therapy was not always significantly superior to that of the TAM treatment.

Anti-tumor effects of the oral administration of the streptococcal preparation OK-432 (PICIBANIL)--the inhibition of carcinogenesis and growth in rats with ENNG-induced gastrointestinal tumors.

We examined whether the Streptococcal preparation OK-432, an immunopotentiating agent, increases immunocompetence of the gut-associated lymphoid system (GALS), inhibits gastrointestinal carcinogenesis, and has an anti-tumor effect. 14C-labelled OK-432 was orally and intraperitoneally administered to rats, and the distribution of the agent in various organs then serially evaluated. The concentration of OK-432 in Peyer's patches and mesenteric lymph nodes was higher after oral administration than after intraperitoneal administration, and showed a biphasic pattern peaking at 30 minutes and 5 hours following administration, in the Peyer's patches. With regard to immunocompetence, PHA- and PWM-stimulated blastogenesis of lymphocytes derived from the mesenteric lymph nodes and peripheral blood enhanced, and the helper/suppressor T-cell ratio was elevated after the oral administration of OK-432. Moreover, chemotactic activity of peritoneal macrophages was also increased. ENNG-induced gastrointestinal carcinogenesis was observed in 60 per cent of the rats orally administered OK-432 as compared with 88 per cent of the controls. The 13-month survival rate of the rats with gastrointestinal cancer was 50 per cent in those administered OK-432 as compared with 25 per cent in those administered OK-432 as compared with 25 per cent in the controls. When administered orally, the agent prevented reduction in immuno-competence in the course of carcinogenesis, suppressed carcinogenesis, and prolonged the survival of animals with cancer without any of the side effects associated with injection. The oral administration of OK-432 is thus considered to be an effective non-specific immunotherapy against gastro-intestinal malignancies.

[A clinical study of immunological status in patients with gastric cancer: with special reference to T-cell subsets, interleukin-2 in the lymphocytes of peripheral blood].

Peripheral blood lymphocytes of 63 patients with gastric cancer were studied by using different monoclonal antibodies and flow cytometry. Used monoclonal antibodies were OKT3 (total T cell), OKT4 (helper/inducer), OKT8 (suppressor/cytotoxic), Leu 7 and Leu 11 (NK/K cell). Interleukin-2 was measured by tritium-labelled thymidine CTLL assay on the supernatant of peripheral blood lymphocytes after 24 hours stimulation with phytohemagglutinin. Interleukin-2 receptor was also studied by using monoclonal antibody (for Tac antigen) and flow cytometry. The results were as follows: among peripheral blood lymphocytes; 1. the number of OKT3, OKT4 cells and the percentage of OKT4 cells decreased significantly with more advanced stage of cancer. 2. production of interleukin-2 also decreased with the progression of the cancer. 3. decreases in the OKT4/OKT8 ratio were found with cancer progression. 4. the percentage and the number of OKT8 cells increased. 5. the percentage and the number of Leu 11 cells and the number of Leu 7 cells were increased significantly in the stage III (moderately advanced cancer). These results suggested that the activated helper T cells decreased, the induction capability of cytotoxic T cells decreased and the suppressor T cells increased with the progression of cancer. Quantitative and qualitative change in T-cell subsets in advanced stage may be one factor responsible for immunosuppression.

[A case report of advanced breast cancer effectively treated with etoposide, adriamycin and cis-platinum combination therapy].

A 61-year-old woman with left advanced breast cancer (T3a, N2, M0, Stage IIIa) underwent preoperative chemotherapy. The regimen consisted of etoposide 70 mg/m2 (day 4, 5, 6 i.v.), adriamycin 20 mg/m2 (day 1, 7 i.v.) and cis-platinum 40 mg/m2 (day 2, 8 i.v.). By the third week of administration, the size of the breast tumor reduced markedly, with the rate of 97%, resulting in partial response. Following preoperative combination-chemotherapy, a left extended radical mastectomy was performed. Histological findings of the resected specimen showed sufficient effects of chemotherapy; degeneration of tumor cells, infiltration of histiocytes and fibrosis of stroma. After operation, chemotherapy with the same dosage and sequential irradiation were undergone. As the side effect of this chemotherapy, slight nausea, vomiting and leucocytopenia were observed. The result of this case suggested that combination-chemotherapy with etoposide, adriamycin and cisplatinum was an effective chemotherapy for advanced breast cancer.