Ophthalmomyiasis caused by Sarcophaga crassipalpis (Diptera: Sarcophagidae) in a hospital patient

Nine sarcophagid larvae were found on the right eyelid, cornea, and bulbar conjunctiva of a debilitated patient in a hospital in Osaka, Japan. Inflammation of the right eyelid and conjunctival congestion, probably initiated or aggravated by the larvae, were found. The larvae were removed and reared for accurate identification, and, on the basis of the characteristics of the 3rd instar and adult flies, the species was identified as Sarcophaga crassipalpis Macquart. This is a report of ophthalmomyiasis caused by this facultative parasite in a human. Patients with diminished consciousness in hospitals need protection from flies.

Sarcoidosis with membranous nephropathy and granulomatous interstitial nephritis

A 49-year-old woman, who had been diagnosed as sarcoidosis based on bilateral hilar lymphadenopathy and lung biopsy, presented increased serum creatinine and calcium concentrations. Renal biopsy showed the presence of interstitial nephritis with non-caseating epithelioid granuloma and focal membranous transformation. Therapy with prednisolone was effective in normalizing serum creatinine, serum calcium, serum angiotensin converting enzyme, and urine beta2 microglobulin, but these abnormalities reappeared after rapid withdrawal of prednisolone. This is a rare case of sarcoidosis manifested by both membranous nephropathy and granulomatous interstitial nephritis, and indicates the necessity of long-term treatment of corticosteroid.

Expression of a dominant negative SHP-2 in transgenic mice induces insulin resistance

To elucidate the roles of SHP-2, we generated transgenic (Tg) mice expressing a dominant negative mutant lacking protein tyrosine phosphatase domain (DeltaPTP). On examining two lines of Tg mice identified by Southern blot, the transgene product was expressed in skeletal muscle, liver, and adipose tissues, and insulin-induced association of insulin receptor substrate 1 with endogenous SHP-2 was inhibited, confirming that DeltaPTP has a dominant negative property. The intraperitoneal glucose loading test demonstrated an increase in blood glucose levels in Tg mice. Plasma insulin levels in Tg mice after 4 h fasting were 3 times greater with comparable blood glucose levels. To estimate insulin sensitivity by a constant glucose, insulin, and somatostatin infusion, steady state blood glucose levels were higher, suggesting the presence of insulin resistance. Furthermore, we observed the impairment of insulin-stimulated glucose uptake in muscle and adipocytes in the presence of physiological concentrations of insulin. Moreover, tyrosine phosphorylation of insulin receptor substrate-1 and stimulation of phosphatidylinositol 3-kinase and Akt kinase activities by insulin were attenuated in muscle and liver. These results indicate that the inhibition of endogenous SHP-2 function by the overexpression of a dominant negative mutant may lead to impaired insulin sensitivity of glucose metabolism, and thus SHP-2 may function to modulate insulin signaling in target tissues.

Role of mitogen-activated protein kinase/extracellular signal-regulated kinase cascade in gonadotropin-releasing hormone-induced growth inhibition of a human ovarian cancer cell line

Although gonadotropin-releasing hormone agonists (GnRHa) have been used in the therapy of the endocrine-dependent cancers, their biological mechanism remained obscure. We have studied the roles of mitogen-activated protein kinase family in the antiproliferative effect of GnRHa on the Caov-3 human ovarian cancer cell line. Reverse transcription-PCR assays confirmed mRNA for GnRH receptor in Caov-3 cells. In the presence of 1 microM GnRHa, the proliferation of cells was significantly reduced to 76% of controls after 24 h, and the effect was sustained up to 4 days. Although GnRHa had no effect on the activation of the Jun N-terminal kinase (JNK), treatment of Caov-3 cells with GnRHa activated extracellular signal-regulated protein kinase (ERK), and its effect was more than that induced by GnRH. Activation of ERK by GnRHa occurred within 5 min, with the maximum occurring at 3 h and sustained until 24 h. GnRHa also activated ERK kinase (mitogen-activated protein/ERK kinase) and resulted in an increase in phosphorylation of son of sevenless (Sos), and Shc. Furthermore, we examined the mechanism by which GnRHa induced ERK activation. Both pertussis toxin (10 ng/ml), which inactivates Gi/Go proteins, and expression of a peptide derived from the carboxyl terminus of the beta-adrenergic receptor kinase I, which specifically blocks signaling mediated by the betagamma subunits of G proteins, blocked the GnRHa-induced ERK activation. Phorbol 12-myristate 13-acetate (PMA) also induced the ERK activity, but pretreatment of the cultured cells with PMA to down-regulate protein kinase C did not abolish the activation of ERK by GnRHa. Elimination of extracellular Ca2+ by EGTA also did not abolish the activation of ERK by GnRHa. To examine the role of ERK cascade in the antiproliferative effect of GnRHa, PD98059, an inhibitor of mitogen-activated protein/ERK kinase, was used. This inhibitor canceled the antiproliferative effect of GnRHa and apparently reversed the GnRH-induced dephosphorylation of the retinoblastoma protein, the hyperphosphorylation of which is a hallmark of G1-S transition in the cell cycle. These results provide evidence that GnRHa stimulation of ERK activity may be mediated by Gbetagamma protein, not by PMA-sensitive protein kinase C nor extracellular Ca2+ in the Caov-3 human ovarian cancer cell line, suggesting that this cascade may play an important role in the antiproliferative effect of GnRHa.

Free radical production in endothelial cells as a pathogenetic factor for vascular dysfunction in the insulin resistance state

Impairment of nitric oxide-dependent vascular relaxation is a characteristic feature of the insulin-resistant state. To understand those mechanisms, we examined imbalance of O2-/NO production in aortic endothelial cells obtained from high fructose-fed, exogenous hyperinsulinemic, and control rats. Aortic segments from both high fructose-fed and insulin-treated rats produced a 4-fold more O2- than control rats evaluated by a chemiluminescence method. The O2- production in the aortas of both high fructose-fed and insulin-treated rats was mediated through activation of NADH/NADPH oxidase. In isometric tension studies, high fructose vessels with endothelium elicited impaired relaxation in response to acetylcholine or a calcium ionophore A23187 when compared with control rats, whereas these impaired vascular responses were not found in insulin-treated rats. Furthermore, endothelial constitutive NO synthase activity was increased in vessels from insulin-treated rats, but decreased in vessels from high fructose-fed rats. These results indicate that relative excess of O2- production through activation of NADH/NADPH oxidase over NO generation in endothelial cells may contribute to impaired endothelial-dependent relaxation in insulin-resistant state.

The role of volume-weighted mean nuclear volume in predicting disease outcome in patients with prostate cancer treated with radical prostatectomy

BACKGROUND

Estimates of volume-weighted mean nuclear volume (MNV) are the only means by which unbiased estimates of three-dimensional parameters can be obtained from single two-dimensional sections without any assumptions. We have reported that for prostate cancer estimates of MNV are prognostically equal or superior to morphological grading of malignancy, such as Gleason score (GS), and in particular, that MNV proved to be a meaningful predictor of prognosis for patients with clinically localized tumors. However, all previous studies were conducted on patients treated conservatively, and no authors have tested whether estimates of MNV can predict the prognosis of patients treated with radical prostatectomy.

MATERIALS AND METHODS

A retrospective prognostic study of 52 patients with clinically localized prostate cancer diagnosed at three Hospitals in Shizuoka Prefecture, Japan (Shizuoka City Hospital, Shizuoka Prefectural Hospital and Shimada Municipal Hospital) and treated by radical prostatectomy was performed. Twenty of these patients were treated with hormone therapy before radical prostatectomy. Unbiased estimates of MNV were compared with clinical stage, histological grading according to GS and neo-adjuvant hormone therapy with regard to the prognostic value.

RESULTS

MNV was significantly correlated with pathological T stage, but was not significantly correlated with the presence or absence of lymph node metastasis. Univariate analysis revealed that MNV correlated significantly with progression-free survival (p = 0.0116). Multivariate analysis revealed that MNV (p = 0.0115) and GS (p = 0.0275) were two significant independent predictors of progression-free survival.

CONCLUSIONS

The results of the present study suggest that MNV and GS are powerful independent predictors of prognosis for prostate cancer treated with radical prostatectomy. We recommend estimates of MNV as a supportive method to the histological grading for patients with prostate cancer.

The 3'-untranslated region polymorphism of the gene for skeletal muscle-specific glycogen-targeting subunit of protein phosphatase 1 in the type 2 diabetic Japanese population

A newly identified 3'-untranslated region (UTR) polymorphism of the gene for skeletal muscle-specific glycogen-targeting subunit of protein phosphatase 1 (PPP1R3) was associated with insulin resistance and type 2 diabetes in Pima Indians (Xia J, Scherers W, Cohen PTW, Majer M, Xi T, Norman RA, Knowler WC, Bogardus C, Prochazka M: A common variant in PP1R3 associated with insulin resistance and type 2 diabetes. Diabetes 47:1519-1524, 1998). Thus, we investigated the frequency of polymorphism of the adenine- and thymine-rich element (ARE-1 and its variant ARE-2) in 426 Japanese type 2 diabetic and 380 nondiabetic subjects using a polymerase chain reaction (PCR)-restriction enzyme fragment length polymorphism (RFLP) method. The allele frequency of the ARE-2 variant in diabetic subjects was higher than that in nondiabetic subjects (0.34 vs. 0.29; P < 0.05), even though its frequency in Japanese subjects was lower (P < 0.001) than the reported value in Pima Indians (0.56). An aspartate polymorphism at codon 905 was 100% coupled to the ARE-2 allele, and its allele frequency was higher also in diabetic subjects. Although a serine substitution at codon 883 was partially linked with the ARE-2 allele, there was no difference between diabetic and nondiabetic subjects. These results indicate that the frequency of polymorphism of the PPP1R3 gene (ARE-2 and Asp905) is different between two ethnic groups and is increased in Japanese people with type 2 diabetes, suggesting that these variants may be a possible marker for searching for diabetogenic genes.

Volume-weighted mean nuclear volume as a prognostic factor in renal cell carcinoma

Volume-weighted mean nuclear volume (MNV) has been reported to have important prognostic value in many cancers. We investigated the prognostic value of MNV in patients with renal cell carcinoma (RCC). A retrospective study of the 155 patients with RCC treated by radical nephrectomy between 1976 and 1996 was conducted. MNV was evaluated in the surgical specimens using a stereologic technique. Univariate analyses by the log-rank test and then a multivariate analysis by the Cox proportional hazards model were performed to analyze the prognostic value of histopathologic parameters such as Robson stage, tumor-node-metastasis (TNM) classification, tumor grade, and MNV. There were significant correlations between MNV and Robson stage, TNM classification and tumor grade. Robson stage, TNM classification, tumor grade, and MNV were correlated significantly with disease-specific survival of RCC patients. There was no significant difference in disease-specific survival between patients with Grade 1 and Grade 2 tumors (94.8% of all patients), but MNV could predict the clinical outcome of these groups. MNV also was correlated significantly with disease-specific survival at all tumor stages. Multivariate analysis showed pT classification, M classification, tumor grade, and MNV to be independently associated with survival. These studies strongly suggest that MNV may provide new and useful information to accurately predict the prognosis of patients with RCC.

Clinicopathological features of superficial depressed-type colorectal neoplastic lesions

OBJECTIVE

We performed this study to analyze the endoscopic findings, dissecting microscopic features, and p53 immunostaining in superficial depressed-type (depressed) colorectal neoplastic lesions.

METHODS

Dissecting stereomicroscopy was used to ascertain the size and pit pattern of lesions removed by endoscopic snare polypectomy. Immunohistochemical staining of p53 was performed with an antigen retrieval system using a monoclonal antibody to p53.

RESULTS

All depressed neoplastic lesions (submucosal carcinoma, n = 6; high-grade dysplasia, n = 14; and adenoma, n = 30) were small (< 1 cm in diameter) and were detected as a depression with or without a marginal elevation on colonoscopic examination. In the dissecting microscopic study, submucosal carcinomas and lesions of high-grade dysplasia almost exclusively showed irregular small pits, with the exception of four malignant lesions with moderate submucosal invasion in which the pit structure was absent. In contrast, adenomas had either regular small (29/30 lesions) or oval pits (1/30 lesions). Rates of p53 positivity were 100%, 64%, and 7% in depressed submucosal carcinomas, lesions of high-grade dysplasia, and adenomas, respectively, thus the prevalence of p53 positivity was significantly higher in the former two groups than in the adenoma group.

CONCLUSIONS

The high frequency of invasive carcinoma and high-grade dysplasia found in depressed colorectal neoplastic tumors, despite their small size, indicates that these lesions may be a subtype of colorectal tumor with more aggressive malignant potential at an earlier stage.

The role of volume-weighted mean nuclear volume in predicting disease outcome in patients with stage M1 prostate cancer

BACKGROUND

Various factors have been reported to be of value in predicting the prognosis of prostate cancer. Gleason score (GS) and prostate-specific antigen (PSA) are the two most powerful prognosticators among them. We previously reported that estimation of volume-weighted mean nuclear volume (MNV) was a more useful prognosticator for prostate cancer than subjective histologic grading. In this study, we compared estimates of MNV with PSA and GS for predicting the prognosis of stage M1 prostate cancer.

EXPERIMENTAL DESIGN

A retrospective prognostic study of 66 patients with stage M1 prostate cancer diagnosed between January 1989 and December 1996 at Shizuoka City Hospital and Shizuoka Prefectural Hospital was performed. The prognostic value of unbiased estimates of MNV were compared with PSA and histologic grading according to GS.

RESULTS

Univariate analysis revealed that estimates of MNV (p=0.0136) and post-treatment nadir PSA level (p<0.0001) correlated significantly with the prognosis of stage M1 prostate cancer, whilst GS (p=0.9377), pre-treatment PSA level (p=0.7377) and rate of decrease in PSA level within 1 month after the beginning of therapy (p=0.8999) had no prognostic value. Multivariate analysis revealed that post-treatment PSA level and estimates of MNV were the two most powerful prognosticators.

CONCLUSIONS

This study indicates that estimation of MNV is an important prognosticator, in conjunction with post-treatment nadir PSA level, in stage M1 prostate cancer.

Intraluminal thyrotropin-releasing hormone affects gastric somatostatin and acid secretion through its specific receptor in rats

BACKGROUND

Although thyrotropin-releasing hormone (TRH) is present in the gastric mucosa and juice, the pathophysiologic significance of TRH is poorly understood at the peripheral level of the stomach. In the present study we analyzed the TRH-induced secretion profiles of somatostatin, histamine, and acid in the rat stomach.

METHODS

The effects of intraluminal perfusion of TRH on somatostatin, histamine, and acid and the influence of the specific anti-TRH receptor antibody were investigated by using the rat gastric intraluminal perfusion model.

RESULTS

Intraluminal TRH caused an immediate decrease in somatostatin secretion in a dose-dependent manner, and this change occurred preceding an increase in acid secretion. In contrast, this treatment did not yield any significant changes in histamine contents in the effluent. Pretreatment of the gastric lumen with the anti-TRH receptor antibody caused a complete inhibition of TRH-induced changes in somatostatin and acid secretion.

CONCLUSIONS

These findings suggest that intraluminal TRH affects somatostatin and acid secretion in a paracrine manner via its specific receptor in the rat stomach.

A new antidiabetic agent (JTT-501) rapidly stimulates glucose disposal rates by enhancing insulin signal transduction in skeletal muscle

A newly synthesized antidiabetic agent, JTT-501 is an isoxazolidinedione rather than a thiazolidinedione. An oral dose of JTT-501 (100 mg x kg(-1) x day(-1)) given to 12-week-old male Zucker fatty rats for 7 days led to the amelioration of both hyperinsulinaemia (40% of non-treated) and hypertriglyceridaemia (23% of non-treated) as well as a 2.4-fold increased insulin sensitivity as determined by a euglycaemic insulin clamp. In our study, we further evaluated the acute effect of JTT-501 on both the glucose infusion rates (GIR) and insulin signalling in skeletal muscle. Male Sprague-Dawley (SD) rats aged 10 weeks were injected intravenously with JTT-501 (5 mg/kg) and then a euglycaemic insulin clamp was initiated and glucose infusion rates monitored for 150 min. We found that this treatment increased the glucose infusion rate by 33% during the last 30 min in SD rats. After the clamp had been initiated for 30 min, the insulin-stimulated phosphatidylinositol 3-kinase (PI3-kinase) activities co-immunoprecipitated with insulin receptor substrate 1 (IRS-1) were also enhanced, resulting in increased glycogen synthase activities in the soleus muscles. Treatment with JTT-501 also enhanced the phosphorylation of insulin receptors and insulin receptor-substrate 1 rapidly as well as the phosphatidylinositol 3-kinase activities, which were stimulated by a bolus injection of insulin. Similarly, JTT-501 stimulated the glucose infusion rate by 30% and enhanced insulin signalling in Zucker fatty rats. In conclusion, a newly developed isoxazolidinedione, JTT-501, rapidly potentiates the insulin sensitivity of skeletal muscle by enhancing insulin signalling and could be useful for the treatment of insulin-resistant diabetic subjects.

Effects of cholesterol-lowering treatments on oxidative modification of plasma intermediate density lipoprotein plus low density lipoprotein fraction in Type 2 diabetic patients

To investigate the normalization of enhanced oxidative modification of the lipoprotein such as increased lysophosphatidylcholine (LPC) and lipid hydroperoxide (LPO) contents in diabetic subjects, we studied the effect of cholesterol-lowering treatment on those parameters in 24 hypercholesterolemic Type 2 diabetic patients. Those patients were randomly assigned to two treatment groups, such as 12 patients treated with pravastatin 10 mg daily and 12 patients treated with probucol 500 mg daily for 8 weeks. Characteristics of the patients including age, gender, body mass index (BMI), smoking habit, modality of diabetic treatment and the glycemic control state were comparable between the two groups. LPC content in the lipoprotein fractions obtained from 24 patients with Type 2 diabetes mellitus was significantly higher than that of non-diabetic control subjects. The abnormality was improved to the control level after a significant improvement of serum cholesterol levels following 8 week-treatments with either probucol or pravastatin without any change in glycemic control (P < 0.025). Furthermore, increased LPO content in the lipoprotein fraction in those diabetics was also significantly (P < 0.0025) improved by the probucol treatment and tended to be improved by pravastatin treatment (P = 0.06). LPC contents in the lipoprotein fraction was positively correlated with LPO contents before cholesterol-lowering treatments (r = 0.41, P < 0.05). These results indicate that cholesterol-lowering treatments effectively reduce oxidative modification of the lipoprotein fraction containing intermediate density lipoprotein (IDL) and low density lipoprotein (LDL) in hypercholesterolemic Type 2 diabetic patients.

Identification of macrophage migration inhibitory factor (MIF) in rat peripheral nerves: its possible involvement in nerve regeneration

Macrophage migration inhibitory factor (MIF) is known as a pluripotent immunoregulatory cytokine involved in T-cell activation and inflammatory responses; however, no study on this protein in the peripheral nervous systems has been carried out. We here demonstrated for the first time expression of MIF mRNA and MIF protein in rat sciatic nerves by reverse transcription-polymerase chain reaction, Western blotting, and immunohistochemistry. Immunohistochemical analysis revealed positive staining of MIF, which was largely observed in Schwann cells. Furthermore, we examined MIF mRNA expression in the sciatic nerves by Northern blot analysis in the case of nerve transection. In both proximal and distal segments, the level of MIF mRNA started to increase 12 h after the nerve transection. The level remained high from 24 h up to day 7 after the injury. During the period from days 14 to 21, MIF mRNA sharply decreased to the pre-transection level. In immunohistochemistry, positive staining of MIF was largely observed in axons as well as non-neuronal cells in proximal segments at day 4 after transection. In the distal segments, contrastingly, endoneurial fibroblasts or Schwann cells migrating into neuronal fibers showed positive staining with Wallerian degeneration. Although the precise functions of MIF in the peripheral nerves remain to be elucidated, the present results could represent a major departure from the current state of knowledge, revealing a novel function in the degenerative-regenerative process.

Increased mucosal production of granulocyte colony-stimulating factor is related to a delay in neutrophil apoptosis in Inflammatory Bowel disease

Tissue accumulation of polymorphonuclear neutrophils (PMN) in Inflammatory Bowel disease (IBD) might be, in part, due to a delay in apoptotic processes associated with the effects of their specific growth factors and inflammatory cytokines. We addressed this hypothesis by examining the activity of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) in the organ culture supernatants of colonic mucosal specimens and their regulatory effects on PMN apoptosis in patients with IBD. The contents of G-CSF and GM-CSF in the supernatants were measured by the enzyme-linked immunosorbent assays and PMN apoptosis was evaluated by acridine orange/ethidium bromide staining, respectively. Mucosal specimens obtained from patients with active IBD exhibited higher levels of G-CSF and GM-CSF activity than controls. Notably, the levels of G-CSF activity were approximately 1000-fold higher than those of GM-CSF activity. Freshly isolated PMN showed a time-related increase in the proportion of cells with characteristic features of apoptosis when they were incubated with the culture medium alone and exposure of PMN to recombinant G-CSF and GM-CSF caused a concentration-dependent inhibition of apoptosis. Incubation of PMN with the supernatants from patients with active IBD induced an inhibitory effect on PMN apoptosis; this effect was abrogated to a significant degree by pre-incubation of the supernatants with anti-G-CSF serum. This study suggests that PMN apoptosis may be delayed under the influence of soluble mediators, especially G-CSF, in the microenvironment of IBD-affected mucosa, thus providing possible mechanisms for tissue accumulation of PMN in IBD.

Effects of parent Shamo cocks on the histochemical properties of M. iliotibialis lateralis and M. supracoracoideus on their crossbred broilers

1. Four Shamo (a Japanese game bird) cocks showing different characteristics in the histochemical properties of M. iliotibialis lateralis (ITL) were crossed with White Rock hens to produce male and female crossbred broilers of the 4 lines (90 d of age). Normal broilers (56 d) were used, for comparison. 2. Histochemical properties of ITL and M. supracoracoideus (SC) were compared among the crossbred lines and normal broilers. Myofibres were divided into Types II R, II I and II W showing high, moderate and low reduced nicotinamide adenine dinucleotide dehydrogenase (NADH-DH) activities, respectively. 3. In the ITL of the crossbred cockerels, the percentage of Type II R and II I fibres decreased and conversely Type II W increased in comparison to those in the Shamo. 4. Sex differences of the histochemical properties were recognised only in the ITL of the crossbred, in which the percentage of Type II R fibres was greater in the male. 5. The different characteristics of the parent Shamo cocks were reproduced only in the different fibre type composition of the ITL muscle in the crossbred cockerels. 6. The histochemical features of fibre type seemed to develop with bird age, particularly subsarcolemmal accumulation of formazan granules (indicating high NADH-DH activity) in Type IIR fibres. 7. Breed, line, sex and age differences in the histochemical properties were demonstrated clearly in ITL but not in SC.

Crosstalk between the interleukin-6 (IL-6)-JAK-STAT and the glucocorticoid-nuclear receptor pathway: synergistic activation of IL-6 response element by IL-6 and glucocorticoid

Cytokines and steroid hormones use different sets of signal transduction pathways, which seem to be unrelated. Interleukin-6 (IL-6) uses JAK tyrosine kinase and STAT (signal transducer and activator of transcription) transcription factor. Glucocorticoid binds glucocorticoid receptor (GR), which is a member of the steroid receptor superfamily. We have studied the crosstalk between the IL-6-JAK-STAT and glucocorticoid-nuclear receptor pathways. IL-6 and glucocorticoid synergistically activated the IL-6 response element on the rat alpha2-macroglobulin promoter (APRE)-driven luciferase gene. The exogenous expression of GR enhanced the synergism. The exogenous expression of dominant negative STAT3 completely abolished the IL-6 plus glucocorticoid-induced activation of the APRE-luciferase gene. Tyrosine phosphorylation of STAT3 stimulated by IL-6 alone was not different from that by IL-6 plus glucocorticoid. The protein level of STAT3 was also not increased by glucocorticoid stimulation. The time course of STAT3 tyrosine phosphorylation by IL-6 plus glucocorticoid was not different from that by IL-6 alone. The synergism was studied on the two other IL-6 response elements, the junB promoter (JRE-IL-6) and the interferon regulatory factor-1 (IRF-1) promoter (IRF-GAS) which could be activated by STAT3. The synergistic activation by glucocorticoid on the IL-6-activated JRE-IL-6 and the IRF-GAS-driven luciferase gene was not detected. Glucocorticoid did not change the mobility of IL-6-induced APRE-binding proteins in a gel shift assay. These results suggest that the synergism was through the GR and STAT3, and the coactivation pathway which was specific for APRE was the target of glucocorticoid.

Messenger RNA differential display reverse-transcriptase-polymerase-chain-reaction analysis of a progestogen-suppressive gene in a human endometrial-cancer cell line

Progestogen suppresses the progression of endometrial cancer and has an important effect on the secretory change of human endometrium. We characterized the progestogen-induced alterations of gene expression in a human endometrial-cancer cell line using a mRNA differential-display reverse-transcriptase-polymerase-chain-reaction (DDRT-PCR) method. After 5-day incubation of Ishikawa endometrial-cancer cells, with or without 100 nM medroxyprogesterone acetate (M PA), total RNA was isolated from confluent cells. We identified 8 candidate genes by mRNA differential display by screening up to approximately 3,000 mRNA species. Among these, 2 genes named T21A and T21B showed a decrease in mRNA by MPA treatment when analyzed by Northern blot. Nucleotide sequence showed that clone T21A was part of human mitochondrial short-chain enoyl-CoA hydratase cDNA. The other clone, T21B, showed no homology with any known nucleotide sequences. Northern-blot analysis using T21A and T21B clones as probes showed a decrease in mRNA in human endometrium from the luteal stage, with high serum estradiol and progesterone levels, as compared with that from the early follicular stage, with low serum estradiol and progesterone levels, and that from the pre-ovulatory stage with high serum estradiol and low progesterone levels. These findings suggest that mRNA DDRT-PCR could be used to identify the candidate genes regulated by progestogen in human endometrial cancer and in normal human endometrium.

Altered activities of transcription factors and their related gene expression in cardiac tissues of diabetic rats

Gene regulation in the cardiovascular tissues of diabetic subjects has been reported to be altered. To examine abnormal activities in transcription factors as a possible cause of this altered gene regulation, we studied the activity of two redox-sensitive transcription factors--nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1)--and the change in the mRNA content of heme oxygenase-1, which is regulated by these transcription factors in the cardiac tissues of rats with streptozotocin-induced diabetes. Increased activity of NF-kappaB and AP-1 but not nuclear transcription-activating factor, as determined by an electrophoretic mobility shift assay, was found in the hearts of 4-week diabetic rats. Glycemic control by a subcutaneous injection of insulin prevented these diabetes-induced changes in transcription factor activity. In accordance with these changes, the mRNA content of heme oxygenase-1 was increased fourfold in 4-week diabetic rats and threefold in 24-week diabetic rats as compared with control rats (P < 0.01 and P < 0.05, respectively). Insulin treatment also consistently prevented changes in the mRNA content of heme oxygenase-1. The oral administration of an antioxidant, probucol, to these diabetic rats partially prevented the elevation of the activity of both NF-kappaB and AP-1, and normalized the mRNA content of heme oxygenase-1 without producing any change in the plasma glucose concentration. These results suggest that elevated oxidative stress is involved in the activation of the transcription factors NF-kappaB and AP-1 in the cardiac tissues of diabetic rats, and that these abnormal activities of transcription factors could be associated with the altered gene regulation observed in the cardiovascular tissues of diabetic rats.

Concerted regulation of early enterocyte differentiation by insulin-like growth factor I, insulin, and transforming growth factor-beta1

To clarify the roles of insulin on the proliferation and differentiation of intestinal epithelial cells (IECs), we examined the effect of insulin-like growth factor-I (IGF-I) and insulin for the growth and differentiation of IEC-6 cells, a crypt cell line derived from rat small intestine. IGF-I (100 nM) stimulated the proliferation of IEC-6 cells, and insulin (1-100 nM) antagonized the IGF-I effect and caused the cells' G1-arrest, resulting in differentiated characteristics of IECs, such as increased general protein synthesis and the formation of microvilli. To clarify the mechanisms of these phenomena, cell surface [125I]insulin binding and the content of immunoreactive insulin receptors were analyzed by Western blotting. Insulin receptors transiently appeared on the cell surface during the early G1 phase after the IGF-I stimulation. Under those conditions, the concomitant presence of insulin stimulated the appearance of active transforming growth factor-beta1 (TGF-beta1) in the media, and then TGF-beta1 antagonized the IGF-I-induced cell proliferation. Such a TGF-beta1 effect was blunted by a neutralizing antibody against TGF-beta1, indicating that the insulin effect was in part mediated through the autocrine-paracrine secretion of TGF-beta1. These results suggest that the regulation of the proliferation of IECs are an early step in those cells' differentiation that may accompany hormonal changes during nutrient intake and may be caused by the sequential effects of IGF-I, insulin, and TGF-beta1.

Human chorionic gonadotropin-alpha gene is transcriptionally activated by epidermal growth factor through cAMP response element in trophoblast cells

The purpose of this study was to analyze the mechanism of transcriptional activation of human chorionic gonadotropin-alpha (hCGalpha) gene by epidermal growth factor (EGF) in trophoblast cells. We stably transfected hCGalpha promoter-chloramphenicol acetyltransferase constructs into Rcho-1 trophoblast cells and monitored the promoter activities. -290-base pair hCGalpha promoter containing a tandem repeat of cAMP response element (CRE) was activated by EGF in a dose- and time-dependent manner. Deletion analysis of hCGalpha promoter suggested an involvement of CRE in EGF-induced hCGalpha transcriptional activation. Moreover, the hCGalpha promoter, of which both CREs were mutated, did not respond to EGF. These results indicate that EGF activates the hCGalpha gene transcription through CRE. Although EGF did not alter the amount of CRE-binding protein (CREB), EGF induced CREB phosphorylation. We next examined the mechanism of CREB phosphorylation by EGF. Protein kinase C inhibitors (H7, staurosporin, and chelerythrine) inhibited EGF-induced CREB phosphorylation, whereas either mitogen-activated protein kinase kinase-1 inhibitor (PD98059) or protein kinase A inhibitor (H8) showed no effect. Furthermore, H7 and staurosporin but not H8 inhibited hCGalpha promoter activation by EGF. In conclusion, EGF promotes hCGalpha gene transcription via the CRE region probably by phosphorylating CREB mainly through the protein kinase C pathway in trophoblast cells.

Autocrine inhibition of leptin production by tumor necrosis factor-alpha (TNF-alpha) through TNF-alpha type-I receptor in vitro

The aim of this study was to find factors which regulate m-leptin secretion during pregnancy. Mouse parametrial adipocytes from day 13 of pregnancy were cultured with or without mouse placental lactogen (mPL)-I, mPL-II, or mouse tumor necrosis factor-alpha (mTNF-alpha) and mouse-leptin (m-leptin) concentration in the medium was assessed by RIA. Up to four days of mPL-I or mPL-II treatment did not affect m-leptin secretion. However, mTNF-alpha, which is produced by adipocytes, significantly inhibited m-leptin secretion in a dose- and time-dependent manner. Antibody to mTNF-alpha completely blocked the inhibitory effect of mTNF-alpha on m-leptin secretion. mTNF-alpha significantly inhibited the expression of m-leptin messenger RNA. Agonistic polyclonal antibody directed against the mTNF-type-I receptor (mTNF-RI) significantly inhibited m-leptin secretion, but the anti-mTNF-RII antibody did not change m-leptin secretion. Moreover, human TNF-alpha (h-TNF-alpha) also inhibited human-leptin (h-leptin) secretion by cultured human adipocytes collected from the subcutaneous fat of pregnant women. These results suggest that TNF-alpha, which is secreted by adipocytes, inhibits m-leptin secretion through mTNF-RI and suggest the presence of an autocrine or paracrine regulation of leptin secretion in human and mouse adipose tissue in vivo.

Effect of intragastric administration of beta-endorphin on thyrotropin-releasing hormone and somatostatin release into gastric lumen of rats

The neuropeptides beta-endorphin (BE), thyrotropin-releasing hormone (TRH), and somatostatin (SOM) in the gastric mucosa have the capacity to regulate gastric function. To clarify the possible role of BE in the interactions of neuropeptides and gastric acid secretion we investigated the effect of the intragastric administration of BE on TRH and SOM release into the gastric lumen. BE (100ng/kg) induced an immediate decrease in TRH release and a reciprocal increase in SOM release into the gastric lumen, followed by the suppression of gastric acid secretion. When various doses of BE (0-500ng/kg) were administered, changes in TRH and SOM occurred in a dose-dependent manner. Pretreatment with naloxone dihydrochloride (5 mg/kg, intraperitoneally) completely inhibited the BE-induced changes in the release of these peptides. These findings suggest that BE has a paracrine effect on TRH and SOM release into the gastric lumen through opioid receptors, and that these interactions may be involved in the regulation of gastric acid secretion.

Role of the CCAAT/enhancer binding protein-alpha transcription factor in the glucocorticoid stimulation of p21waf1/cip1 gene promoter activity in growth-arrested rat hepatoma cells

The preceding paper (Cha, H. H., Cram, E. J., Wang, E. C., Huang, A. J., Kasler, H. G., and Firestone, G. L. (1998) J. Biol. Chem. 273, 0000-0000(478563) defined a glucocorticoid responsive region within teh promoter of the p21 CDK inhibitor gene that contains a putative DNA-binding site for the transcription factor CCAAT/ enhancer binding protein-alpha (C/EBP alpha). Wild type rat BDS1 hepatoma cells as well as as4 hepatoma cells, which express antisense sequences to C/EBP alpha and ablate its protein production, were utilized to investigate the role of this transcription factor in the glucocorticoid regulation of p21 gene expression. The stimulation of p21 protein levels and promoter activity, as well as inhibition of CDK2-mediated retinoblastoma protein phosphorylation, by the synthetic glucocorticoid, dexamethasone, required the expression of C/EBP alpha. Overexpression of C/EBP alpha in as4 cells rescued the dexamethasone responsiveness of the p21 promoter. Site-directed mutagenesis of the p21 promoter revealed that dexamethasone stimulation of p21 promoter activity required the C/EBP consensus DNA-binding site. Furthermore, in glucocorticoid receptor-defective EDR1 hepatoma cells, dexamethasone failed to stimulate C/EBP alpha and p21 protein expression and promoter activities. Our results have established a functional link between the glucocorticoid receptor signaling pathway that mediates a G1 cell cycle arrest of rat hepatoma cells and the transcriptional control of p21 by a cascade that requires the steroid induction of C/EBP alpha gene expression.

Pyruvate improves deleterious effects of high glucose on activation of pentose phosphate pathway and glutathione redox cycle in endothelial cells

In our previous study (Diabetes 44:520-526, 1995), endothelial cells cultured in high glucose condition showed impairment of an oxidant-induced activation of the pentose phosphate pathway (PPP) and a reduced supply of NADPH to the glutathione redox cycle. To gain insight into the mechanisms of this impairment, the protective effect of pyruvate was studied in human umbilical vein endothelial cells cultured in either 5.5 mmol/l glucose (normal glucose [NG] condition) or 33 mmol/l glucose (high glucose [HG] condition). Through pretreatment of cells with 0.2 mmol/l pyruvate for 5-7 days in the HG condition, glucose oxidation through the PPP and total cellular NADPH content in the presence of 0.2 mmol/l H2O2 were increased by 54 (P < 0.05) and 34%, respectively, and glutathione-dependent degradation of H2O2 in HG cells was enhanced by 41% (P < 0.01), when compared with those cells to which pyruvate was not added. The addition of pyruvate significantly reduced the fructose 1,6-bisphosphate (FDP) content and free cytoplasmic NADH/NAD ratio, estimated by increased pyruvate/lactate ratio in NG and HG cells exposed to H2O2. Furthermore, the addition of pyruvate also showed a 46% reduction (P < 0.01) of endothelial cell damage induced by H2O2 in HG cells. These results indicate that abnormalities in PPP activation and glutathione redox cycle activity induced by H2O2 in HG cells are compensated, and that the accentuated reductive stress is improved by an addition of pyruvate. These pyruvate effects are associated with protection against an oxidant-induced endothelial cell injury in the high glucose condition.

Cilostazol, a cAMP phosphodiesterase inhibitor, attenuates the production of monocyte chemoattractant protein-1 in response to tumor necrosis factor-alpha in vascular endothelial cells

The induction of monocyte chemoattractant protein-1 (MCP-1) in vascular endothelial cells is thought to be an initial event in the development of atherosclerotic lesions. Therefore, inhibition of MCP-1 production may exhibit some effects in preventing atherosclerosis. In the present study, we found that 10 microM cilostazol, a cAMP phosphodiesterase inhibitor, increased the intracellular cAMP content by a twenty-five times of the basal level and resulted in the reduction of basal MCP-1 release by 41% from 168 +/- 11 ng/24 hr/mg protein to 99 +/- 14 ng/24 hr/mg protein (P < 0.001) from cultured human umbilical vein endothelial cells. Furthermore, 10 microM cilostazol also significantly attenuated the dose-dependent increment of MCP-1 production by tumor necrosis factor-alpha. The inhibition was consistent with the reduction of MCP-1 mRNA level, possibly through reduced activation of transcription factor NF-kappa B level. Similarly, 1 mM dibutyryl cAMP inhibited MCP-1 production in endothelial cells. These data suggest that cilostazol inhibits MCP-1 production through increased intracellular cAMP levels and modulation of its expression in vascular endothelial cells.

Oxidized lipoproteins found in patients with NIDDM stimulate radical-induced monocyte chemoattractant protein-1 mRNA expression in cultured human endothelial cells

Although oxidized low density lipoprotein (LDL) exists in plasma from diabetic patients, there are few studies on its biological activity. Thus, we investigated the biological potency of LDL plus intermediate density lipoprotein fraction isolated from 12 non-diabetic and 24 non-insulin-dependent diabetic subjects of similar age and body mass index, in order to induce monocyte chemoattractant protein-1 (MCP-1) mRNA expression in cultured human endothelial cells. MCP-1 mRNA content in the cells exposed to the lipoproteins isolated from the diabetic patients was significantly higher than that from the control subjects (p < 0.001). The increment of MCP-1 mRNA content was positively correlated with not only HbA1c (r = 0.58, p < 0.0001) but also lysophosphatidylcholine (LPC) content in the lipoprotein (r = 0.46, p < 0.005) and was negatively correlated with diene formation lag time as a marker of oxidizability of the lipoprotein (r = -0.33, p < 0.05). Treatments of the cells with either 50 mumol/l probucol, 50 mumol/l alpha-tocopherol, or 0.1 mmol/l deferoxamine suppressed the increase in MCP-1 mRNA content induced by diabetic lipoproteins, respectively. Furthermore, the diabetic lipoproteins activated nuclear transcription factor NF-kappa B in the cells, which was inhibited by pre-treatment of cells with 50 mumol/l probucol. These data indicate that oxidatively modified lipoproteins found in diabetic plasma stimulate MCP-1 gene expression in endothelial cells. The LPC content which reflects oxidative modification of lipoprotein is at least a possible marker of biological activity to increase an atherogenic cytokine in endothelial cells.

beta-Sitosterolemia with generalized eruptive xanthomatosis

The clinical features of the first case of a patient with sitosterolemia and generalized eruptive xanthomatosis are described. A six-year-old girl with generalized eruption was referred to the lipid clinic because of the high plasma cholesterol levels determined by the enzymatic method. Neither clinical signs nor results of laboratory examinations appeared to be abnormal, except for the eruption and the increase in the plasma cholesterol concentration. A family survey revealed high plasma cholesterol concentrations in the mother and one of two other siblings. Histological examination showed the eruption to be a xanthoma. Plasma sterol analysis by high-performance liquid chromatography revealed a noticeable increase in plasma plant sterol as well as cholestanol concentrations in the proband and the hypercholesterolemic sibling. The other family members had slightly high plasma sterol concentrations. This is the first case of a sitosterolemic patient with eruptive xanthomatosis. The case indicates that the clinical features of the xanthoma in sitosterolemia are not only tuberous or tendon but also eruptive, and also suggests that sitosterolemia should be considered in the differential diagnosis of hypercholesterolemia in almost every case with tuberous or eruptive xanthoma. The diagnosis is clinically important, since the disease can be treated successfully by diet therapy and bile acid binding resins.

A 460-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 40.1-50.0 min region on the linkage map

The 465,813 base pair sequence corresponding to the 40.1-50.0 min region on the genetic map of Escherichia coli K-12 (W3110) was determined. Analysis of the sequence revealed that this region contained at least 466 potential open reading frames, of which 187 (40%) were previously reported, 105 (23%) were homologous to other known genes, 103 (22%) were identical or similar to hypothetical genes registered in databases, and the remaining 71 (15%) did not show a significant similarity to any other gene. At the 45.2-46.0 min region, we found a very large cluster of about 30 genes, whose functions are involved in the biosynthesis of polysaccharides as the components of outer membranes. In addition, we identified a new asn-tRNA gene, designated asnW, between the asnT and asnU genes and a new lysogenic phage attachment site as the cis-element.

A 570-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 28.0-40.1 min region on the linkage map

The 569,750 base pair sequence corresponding to the 28.0-40.1 min region on the genetic map of Escherichia coli K-12 (W3110) was determined. This region includes the replication terminus region and contained at least 549 potential open reading frames. Among them, 160 (29%) were previously reported, 174 (32%) were homologous to other known genes, 102 (18%) were identical or similar to hypothetical genes registered in databases, and the remaining 113 (21%) did not show a significant similarity to any other gene. Of interest was the finding of a large number of genes and gene clusters in and near the replication termination region which had been thought to be genetically silent. Those included a cluster of genes for fatty acid beta-oxidation, the third copy of the pot (spermidine/putrescine transport system) gene cluster, the second dpp (dipeptide transport system) operon, the second dsm (anaerobic dimethyl sulfoxide reductase) operon, a cluster of fim (fimbrial) genes and a DNA helicase-like gene with a high molecular weight. In addition, we found the dnaC- and dnaT-like genes in the cryptic prophage, Rac, and a number of genes originated probably from plasmids.

Neoadjuvant chemotherapy in scirrhous cancer of the stomach using uracil and tegafur and cisplatin

We administered a mixture of uracil and tegafur (UFT)/cisplatin (CDDP) chemotherapy in 28 patients with scirrhous gastric cancer. In the regimen, UFT was orally administered at a dose of 200 mg/m2 twice a day. The CDDP was administered at a dose of 90 mg/m2 by 24-hour continuous infusion every 4 weeks. As a result, antitumor effects for primary gastric foci were achieved in 14 of the 28 patients (50%). Ascites from peritoneal dissemination disappeared completely in eight of 13 patients (62%). Total gastrectomy was performed in ten patients after 2 to 3 courses of chemotherapy. Histological response grades assessed on the resected specimen were Grade 2 in four, Grade 1b in three, Grade 1a in one and Grade 0 in two patients. Neoadjuvant chemotherapy is feasible against scirrhous gastric cancer and a subsequent prospective randomized trial should be prepared to clarify the survival benefit of the treatment.

Insulin signaling and its regulation of system A amino acid uptake in cultured rat vascular smooth muscle cells

Hyperinsulinemia has been recognized as an independent risk factor for atherosclerosis. However, its exact mechanisms are still unclear. In our previous work, we showed that 10 nmol/L insulin stimulated neither mitogen-activated protein kinase (MAP kinase) activity nor [3H]thymidine incorporation but did stimulated S6 kinase through the specific insulin receptors in cultured rat vascular smooth muscle cells (VSMCs). In this study, we observed that > or = 1 nmol/L insulin stimulated tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1) and activated IRS-1-dependent phosphatidylinositol 3'-kinase (PI 3'-kinase) and p70 S6 kinase (p70S6K) but not MAP kinase (extracellular signal-regulated kinase 2) and p90 S6 kinase (p90RSK). However, 10 nmol/L insulin-like growth factor I stimulated all these pathways. Finally, 10 nmol/L insulin stimulated alpha-amino-isobutyric acid (AIB) uptake, and wortmannin (100 nmol/L) completely inhibited insulin-stimulated AIB uptake, whereas rapamycin (20 nmol/L) had no such effect. Furthermore, cycloheximide (10 micrograms/mL) completely inhibited insulin-stimulated AIB uptake, but actinomycin D (5 micrograms/mL) failed to inhibit this. Thus, we reached the following conclusions: (1) Insulin (1 nmol/L) induced phosphorylation of IRS-1 and activated the PI 3'-kinase and p70S6K pathways in VSMCs, even though 10 nmol/L insulin did not significantly stimulate MAP kinase or p90RSK. (2) Stimulation of AIB uptake by insulin was regulated at the translational level via wortmannin-sensitive pathways but not p70S6K pathways.

SHPTP2 serves adapter protein linking between Janus kinase 2 and insulin receptor substrates

To investigate the role of Janus kinase family (JAK1 and JAK2) in insulin signaling, we assessed their insulin-induced associations with other molecules in the cells overexpressing insulin receptors (HIRc and CHO-IR). After insulin stimulation, pp185 proteins (insulin receptor substrate, IRS) were co-immunoprecipitated with both kinases by alpha JAK1 and alpha JAK2 antibodies. However, JAK2 constitutively associated with pp95 protein (IR beta). Moreover, JAK2 also constitutively bound to a protein tyrosine phosphatase containing Src 2 regions (SHPTP2), but JAK1 did not. In HIRc cells expressing PTPase-negative mutant SHPTP2, no association of JAK2 with either pp185 or pp95 was detected. Thus, SHPTP2 might serve as an adapter protein linking between JAK2 and IRS. These results suggest that JAK1 and JAK2 behave differently and they may constitute a new regulatory component in insulin signaling.

Glucocorticoid-stimulated CCAAT/enhancer-binding protein alpha expression is required for steroid-induced G1 cell cycle arrest of minimal-deviation rat hepatoma cells

By genetic correlation with the growth-suppressible phenotype and direct functional tests, we demonstrate that the glucocorticoid-stimulated expression of the CCAAT/enhancer-binding protein alpha (C/EBP alpha) transcription factor is required for the steroid-mediated G1 cell cycle arrest of minimal-deviation rat hepatoma cells. Comparison of C/EBP alpha transcript and active protein levels induced by the synthetic glucocorticoid dexamethasone in glucocorticoid growth-suppressible (BDS1), nonsuppressible receptor-positive (EDR1) and nonsuppressible receptor-deficient (EDR3) hepatoma cell proliferative variants revealed that the stimulation of C/EBP alpha expression is a rapid, glucocorticoid receptor-mediated response associated with the G1 cell cycle arrest. Consistent with the role of C/EBP alpha as a critical intermediate in the growth suppression response, maximal induction of transcription factor mRNA occurred within 2 h of dexamethasone treatment whereas maximal inhibition of [3H] thymidine incorporation was observed 24 h after steroid treatment. As a direct functional approach, ablation of C/EBP alpha protein expression and DNA-binding activity by transfection of an antisense C/EBP alpha expression vector blocked the dexamethasone-induced G1 cell cycle arrest of hepatoma cells but did not alter general glucocorticoid responsiveness. Transforming growth factor beta induced a G1 cell cycle arrest in C/EBP alpha antisense transfected cells, demonstrating the specific involvement of C/EBP alpha in the glucocorticoid growth suppression response. Constitutive expression of a conditionally activated form of C/EBP alpha caused a G1 cell cycle arrest of BDS1 hepatoma cells in the absence of glucocorticoids. In contrast, overexpression of C/EBP beta or C/EBP delta had no effect on hepatoma cell growth. Taken together, these results demonstrate that the steroid-induced expression of C/EBP alpha is necessary to mediate the glucocorticoid G1 cell cycle arrest of rat hepatoma cells and implicates a role for this transcription factor in the growth control of liver-derived epithelial tumor cells.

Abnormal neuropeptide concentration in rectal mucosa of patients with inflammatory bowel disease

Regulatory neuropeptides are widely distributed in the gastrointestinal tract, where they play an important role in motility, secretion, and immune and inflammatory responses. In this study, the rectal mucosal content of somatostatin (SOM), substance P (SP), beta-endorphin (BE), and thyrotropin-releasing hormone (TRH) was measured by radioimmunoassay in 56 patients with ulcerative colitis (UC), 15 patients with Crohn's disease (CD), 15 patients with acute infectious colitis (AIC), and 11 controls, who showed no inflammation of the rectal mucosa, nor abnormal bowel movements. The content of immunoreactive (ir)-SOM was decreased in UC patients, especially in those with persistent disease activity, while the levels of ir-SP, BE, and TRH were increased in such patients. Some changes of ir-peptide levels were also observed in CD and AIC patients. The changes in neuropeptide levels were analyzed in relation to histological grades of inflammation in UC patients, grades 4-5 showing the most significant changes. The levels of ir-SOM, SP, BE, and TRH showed no significant change in chronic persistent UC when measured 6-12 months after the initial examination. In contrast, in patients with remitting intermittent UC, the levels of SP and BE decreased during remission. Abnormal intestinal neuropeptide content may be implicated in the continued mucosal immune and inflammatory responses that are manifested in patients with inflammatory bowel disease.

Glycation, oxidative stress, and scavenger activity: glucose metabolism and radical scavenger dysfunction in endothelial cells

It has been reported that oxidative stress is increased in vivo in the diabetic state. Increased oxidative stress is caused not only by accelerated production of oxygen-free radicals but also by decreased scavenging of those molecules. Endothelial cells are extremely sensitive to oxidative stress, resulting in impairments of various endothelial cell function. In this report, we studied the association of intracellular glucose metabolism and oxygen radical scavenging function via the glutathione redox (GR) cycle in cells exposed to high-glucose conditions using cultured human umbilical vein endothelial cells. Glutathione-dependent H2O2 degradation in cells exposed to 33 mmol/l glucose (HG) for 5-7 days was reduced by 48% vs. 5.5 mmol/l glucose (NG). This impairment under the oxidative stress was D-glucose-specific and concentration-dependent and was also associated with a 42% decrease in intracellular NADPH content. Exposure of cells to 200 micromol/l H2O2 stimulated the GR cycle and the pentose phosphate pathway (PPP) at the same time. In the HG condition, activation of PPP was reduced by 50%, which was consistent with a decrease in NADPH content. Inhibition of glycolysis by H2O2 was less marked in HG cells versus NG cells. Activation of polyol pathway in HG cells is not responsible for the decrease in intracellular NADPH content. These results indicate that activation of the PPP and NADPH supply to the GR cycle is impaired in HG cells exposed to H2O2, which may result in increased oxidative stress to endothelial cells.

Lattice corneal dystrophy type II associated with familial amyloid polyneuropathy type IV

BACKGROUND

Finnish-type familial amyloidosis (FAP-IV) is an autosomal, dominantly inherited disorder characterized by progressive polyneuropathy and lattice corneal dystrophy type II. The vast majority of families with this disorder originated from Finland. Only two families, in neighboring districts, have been reported in Japan previously.

METHODS

The authors report two additional Japanese patients with FAF-IV. The proband, a 70-year-old man, had decreased perspiration and abnormal facial muscle movement. Results of neurologic examination showed bilateral facial and hypoglossal nerve palsies, and an autonomic disturbance, including orthostatic hypotension and dysfunction of perspiration. Histochemical, immunohistological, and DNA studies confirmed the diagnosis of FAP-IV.

RESULTS

Results of ophthalmologic examination showed asymptomatic lattice corneal dystrophy of both eyes, but the appearance of the cornea was different from that described in the patients from Finland. Lattice lines in the authors' patient were very fine, short, and glassy and could be observed with indirect retroillumination, but might be missed with direct illumination by the slit-lamp microscope. The proband's younger half-sister, a 68-year-old woman, showed clinical findings and laboratory data similar to those of the proband.

CONCLUSION

The authors report two Japanese patients with lattice corneal dystrophy type II related to FAP-IV. This is the third Japanese family with this disorder, and there is no familial relationship to the two previously reported families in Japan.

Biochemical and molecular mechanisms in the development of diabetic vascular complications

Hyperglycemia is the major causal factor in the development of diabetic vascular complications. The mechanism by which hyperglycemia causes the complications is not clear; however, it is very likely that hyperglycemia is mediating its adverse effects through multiple mechanisms. We have summarized some of these mechanisms in this review, with particular attention to the effect of hyperglycemia on the activation of diacylglycerol (DAG)-protein kinase C (PKC) pathway. We have reviewed existing information regarding various vascular tissues that show increased DAG and PKC levels. In addition, the mechanism by which hyperglycemia increases DAG as well as the cellular physiological consequences on the activation of PKC have been reviewed.

A 718-kb DNA sequence of the Escherichia coli K-12 genome corresponding to the 12.7-28.0 min region on the linkage map

The 718,122 base pair sequence of the Escherichia coli K-12 genome corresponding to the region from 12.7 to 28.0 minutes on the genetic map is described. This region contains at least 681 potential open reading frames, of which 277 (41%) have been previously identified, 147 (22%) are homologous to other known genes, 139 (20%) are identical or similar to the hypothetical genes registered in databases, and the remaining 118 (17%) do not show a significant similarity to any other gene. In this region, we assigned a cluster of cit genes encoding multienzyme citrate lyase, two clusters of fimbrial genes and a set of lysogenic phage genes encoding integrase, excisionase and repressor in the e14 genetic element. In addition, a new valine tRNA gene, designated valZ, and a family of long directly repeated sequences, LDR-A, -B and -C, were found.

Identification of alternative splicing form of Stat2

We identified alternatively spliced forms of Stat2 in human and mouse mRNAs. The spliced forms are generated by reading through the intron between exon 20 and 21, which correspond to the region encoding SH2 domain. The spliced forms contain a stop codon in SH2 domain, and therefore give rise to a short form of Stat2 when the mRNAs are translated. The putative translated proteins lack half of the SH2 domain, the tyrosine phosphorylation site required for dimerization (or oligomerization) and DNA binding, and C-terminal activation domain. The significance of these spliced forms is discussed.

Identification and characterization of a gene regulating enzymatic glycosylation which is induced by diabetes and hyperglycemia specifically in rat cardiac tissue

Primary cardiac abnormalities have been frequently reported in patients with diabetes probably due to metabolic consequences of the disease. Approximately 2,000 mRNA species from the heart of streptozotocin-induced diabetic and control rats were compared by the mRNA differential display method, two of eight candidate clones thus isolated (DH1 and 13) were confirmed by Northern blot analysis. The expression of clone 13 was increased in the heart by 3.5-fold (P < 0.05) and decreased in the aorta by twofold (P < 0.05) in diabetes as compared to control. Sequence analysis showed that clone 13 is a rat mitochondrial gene. DH1 was predominantly expressed in the heart with an expression level 6.8-fold higher in the diabetic rats than in control (P < 0.001). Insulin treatment significantly (P < 0.001) normalized the expression of DH1 in the hearts of diabetic rats. DH1 expression was observed in cultured rat cardiomyocytes, but not in aortic smooth muscle cells or in cardiac derived fibroblasts. The expression in cardiomyocytes was regulated by insulin and glucose concentration of culture media. The full length cDNA of DH1 had a single open-reading frame with 85 and 92% amino acid identity to human and mouse UDP-GlcNAc:Gal beta 1-3GalNAc alpha R beta 1-6 N-acetylglucosaminyltransferase (core 2 GlcNAc-T), respectively, a key enzyme determining the structure of O-linked glycosylation. Transient transfection of DH1 cDNA into Cos7 cells conferred core 2 GlcNAc-T enzyme activity. In vivo, core 2 GlcNAc-T activity was increased by 82% (P < 0.05) in diabetic hearts vs controls, while the enzymes GlcNAc-TI and GlcNAc-TV responsible for N-linked glycosylation were unchanged. These results suggest that core 2 GlcNAc-T is specifically induced in the heart by diabetes or hyperglycemia. The induction of this enzyme may be responsible for the increase in the deposition of glycoconjugates and the abnormal functions found in the hearts of diabetic rats.