Effects of angiotensin on the expression of fibrosis-associated cytokines, growth factors, and matrix proteins in human lung fibroblasts.

BACKGROUND AND OBJECTIVES: Angiotensin (Ang) II plays an important role in fibrogenesis in various organs, including the lung. The aim of this study is to elucidate (i) the effects of Ang II on the expression of cytokines, growth factors or matrix proteins in normal human lung fibroblasts, and (ii) the inhibitory effects of an Ang II type 1 (AT1) receptor blocker, candesartan. METHODS: Normal human adult lung fibroblasts were cultured. Candesartan was added and the cells were incubated. All the cells in culture dishes were collected at day 0 and 2, and the cell numbers were counted using a Neubauer haemocytometer (Clay-Adams, Parsippany, NJ, USA). The cell proliferation rates at day 2 were calculated in comparison to those at day 0. Total cellular RNA was extracted for real-time quantitative PCR, or the culture supernatant was collected for either a Sircol assay or enzyme-linked immunosorbent assay (ELISA). Laser scanning confocal microscopy was used for analyzing the cells with and without prior exposure to candesartan. Comparisons between the means of multiple groups were analyzed by one-way analysis of variance (ANOVA) followed by Tukey's test or Games-Howell's test. Values of P < 0*05 were considered to be statistically significant. RESULTS: Among the 12 fibrosis-associated cytokines and growth factors, mRNA expressions of interleukin (IL)-4, IL-7, and platelet-derived growth factor-D were significantly modulated by Ang II, and suppressed by candesartan. Soluble collagen and elastin levels were significantly elevated by Ang II, and suppressed by candesartan. Under confocal microscopy, the intracellular distribution of elastin was significantly increased by Ang II, and suppressed by candesartan. CONCLUSION: These data indicate that Ang II promotes lung fibrosis by increasing the matrix formation, which was suppressed by AT1 receptor blocker.

Positive and negative aspects of the human immunodeficiency virus protease: development of inhibitors versus its role in AIDS pathogenesis.

In this review we summarize multiple aspects of the human immunodeficiency virus (HIV) protease from both structural and functional viewpoints. After an introductory overview, we provide an up-to-date status report on protease inhibitors (PI). This proceeds from a discussion of PI structural design, to how PI are optimally utilized in highly active antiretroviral triple therapy (one PI along with two reverse transcriptase inhibitors), the emergence of PI resistance, and the natural role of secretory leukocyte PI. Then we switch to another focus: the interaction of HIV protease with other genes in acute and persistent infection, which in turn may have an effect on AIDS pathogenesis. We conclude with a discussion on future directions in HIV treatment, involving multiple-target anti-HIV therapy, vaccine development, and novel reactivation-inhibitory reagents.

Clinical characteristics of patients with both anti-U1RNP and anti-centromere antibodies.

OBJECTIVE: To clarify the clinical characteristics of patients having both anti-U1RNP antibodies (anti-U1RNP) and anti-centromere antibodies (ACA) in comparison to subjects having either anti-U1RNP or ACA alone. SUBJECTS AND METHODS: One hundred and fifty-six subjects who had anti-U1RNP and/or ACA were enrolled. They were classified into three groups: anti-U1RNP alone group (n = 64); ACA alone group (n = 82); and anti-U1RNP+ACA group (n = 10). The anti-U1RNP alone and ACA alone groups were also divided into the low-titre and the high-titre subgroups, respectively. The frequencies of the specific clinical findings and laboratory data were compared among the groups or subgroups. RESULTS: The frequencies of persistent proteinuria or lupus nephritis (LN, 50.0%) and primary biliary cirrhosis (PBC, 30.0%) in the anti-U1RNP+ACA group were higher than that in the anti-U1RNP alone group (17.2%, p<0.01; 3.1%, p = 0.075; respectively). The frequencies of systemic lupus erythematosus (SLE, 60.0%), persistent proteinuria or LN (50.0%), anti-Ro (70.0%), and anti-La (30.0%) in the anti-U1RNP+ACA group were higher than those in the ACA alone group (11.0%, p<0.01; 4.9%, p<0.001; 23.2%, p<0.01; and 6.1%, p = 0.085; respectively). The frequency of systemic sclerosis (SSc) in the high-titre subgroup (30.0%) was higher than that in the low-titre subgroup (11.8%) in the anti-U1RNP alone group, without significance (p = 0.072). The frequency of interstitial pneumonia in the high-titre subgroup (26.8%) was higher than that in the low-titre subgroup (2.4%) in the ACA alone group (p<0.01). CONCLUSIONS: The clinical characteristics of patients with anti-U1RNP+ACA were clarified in comparison to subjects having either anti-U1RNP or ACA alone.

Tumor necrosis factor-alpha- and hyperglycemia-induced insulin resistance. Evidence for different mechanisms and different effects on insulin signaling.

Inhibition of insulin receptor signaling by high glucose levels and by TNF-alpha was recently observed in different cell systems. The aim of the present study was to characterize the mechanism of TNF-alpha-induced insulin receptor inhibition and to compare the consequences of TNF-alpha- and hyperglycemia-induced insulin receptor inhibition for signal transduction downstream from the IR. TNF-alpha (0.5-10 nM) and high glucose (25 mM) showed similar rapid kinetics of inhibition (5-10 min, > 50%) of insulin receptor autophosphorylation in NIH3T3 cells overexpressing the human insulin receptor. TNF-alpha effects were completely prevented by the phosphotyrosine phosphatase (PTPase) inhibitors orthovanadate (40 microM) and phenylarsenoxide (35 microM), but they were unaffected by the protein kinase C (PKC) inhibitor H7 (0.1 mM), the phosphatidylinositol-3 kinase inhibitor wortmannin (5 microM), and the thiazolidindione troglitazone (CS045) (2 microgram/ml). In contrast, glucose effects were prevented by PKC inhibitors and CS045 but unaffected by PTPase inhibitors and wortmannin. To assess effects on downstream signaling, tyrosine phosphorylation of the following substrate proteins of the insulin receptor was determined: insulin receptor substrate-1, the coupling protein Shc, focal adhesion kinase (FAK125), and unidentified proteins of 130 kD, 60 kD. Hyperglycemia (25 mM glucose) and TNF-alpha showed analogous (> 50% inhibition) effects on tyrosine phosphorylation of insulin receptor substrate-1, Shc, p60, and p44, whereas opposite effects were observed for tyrosine phosphorylation of FAK125, which is dephosphorylated after insulin stimulation. Whereas TNF-alpha did not prevent insulin-induced dephosphorylation of FAK125, 25 mM glucose blocked this insulin effect completely. In summary, the data suggest that TNF-alpha and high glucose modulate insulin receptor-signaling through different mechanisms: (a) TNF-alpha modulates insulin receptor signals by PTPase activation, whereas glucose acts through activation of PKC. (b) Differences in modulation of the insulin receptor signaling cascade are found with TNF-alpha and high glucose: Hyperglycemia-induced insulin receptor inhibition blocks both insulin receptor-dependent tyrosine phosphorylation and dephosphorylation of insulin receptor substrate proteins. In contrast, TNF-alpha blocks only substrate phosphorylation, and it does not block insulin-induced substrate dephosphorylation. The different effects on FAK125 regulation allow the speculation that long-term cell effects related to FAK125 activity might develop in a different way in hyperglycemia- and TNF-alpha-dependent insulin resistance.

Troglitazone increases the number of small adipocytes without the change of white adipose tissue mass in obese Zucker rats.

Troglitazone (CS-045) is one of the thiazolidinediones that activate the peroxisome proliferator-activated receptor gamma (PPARgamma), which is expressed primarily in adipose tissues. To elucidate the mechanism by which troglitazone relieves insulin resistance in vivo, we studied its effects on the white adipose tissues of an obese animal model (obese Zucker rat). Administration of troglitazone for 15 d normalized mild hyperglycemia and marked hyperinsulinemia in these rats. Plasma triglyceride level was decreased by troglitazone in both obese and lean rats. Troglitazone did not change the total weight of white adipose tissues but increased the number of small adipocytes (< 2,500 micron2) approximately fourfold in both retroperitoneal and subcutaneous adipose tissues of obese rats. It also decreased the number of large adipocytes (> 5,000 micron2) by approximately 50%. In fact, the percentage of apoptotic nuclei was approximately 2.5-fold higher in the troglitazone-treated retroperitoneal white adipose tissue than control. Concomitantly, troglitazone normalized the expression levels of TNF-alpha which were elevated by 2- and 1.4-fold in the retroperitoneal and mesenteric white adipose tissues of the obese rats, respectively. Troglitazone also caused a dramatic decrease in the expression levels of leptin, which were increased by 4-10-fold in the white adipose tissues of obese rats. These results suggest that the primary action of troglitazone may be to increase the number of small adipocytes in white adipose tissues, presumably via PPARgamma. The increased number of small adipocytes and the decreased number of large adipocytes in white adipose tissues of troglitazone-treated obese rats appear to be an important mechanism by which increased expression levels of TNF-alpha and higher levels of plasma lipids are normalized, leading to alleviation of insulin resistance.

Outcomes of hepatic artery infusion therapy for hepatic metastases from colorectal carcinoma after radiological placement of infusion catheters.

AIM: The aim of this study is to evaluate the safety and efficacy of hepatic artery infusion (HAI) of 5-fluorouracil (5FU) for patients with liver metastases from colorectal carcinoma after radiological placement of infusion catheters. METHODS: Forty-two patients with liver metastases from colorectal carcinoma received radiological placement of infusion catheters using the distal fixation method. They received continuous HAI of 5FU 1,000-1,500mg for 5h weekly or biweekly. Tumor status was assessed by chest-abdominal computed tomography (CT) scan after every 10 infusions. Hepatic perfusion was checked by CT arteriography via the infusion port after every 10 infusions. RESULTS: Radiological placements of catheters were performed successfully in all cases. Each patient received an average of 36 treatments (range: 10-98). Catheter failure was found in 3 patients (7.1%). Nine incidents of grade 1 toxicity were observed in 8 patients (19.0%). There was a complete response in 6 patients, partial remission in 18, stable disease in 9, and progression of disease in 9 (response rate: 57.1%). Overall median survival time was 29.1 months. Using Cox's proportional hazard model, lymph node metastases in primary colorectal carcinoma and pre-treatment serum CEA affected overall survival (P=0.011, P=0.005). CONCLUSIONS: HAI after radiological placement of infusion catheters is a safe and effective treatment particularly for patients with no lymph node metastasis in primary carcinoma or with a low pre-treatment serum CEA level.

Characterization of new oral antidiabetic agent CS-045. Studies in KK and ob/ob mice and Zucker fatty rats.

CS-045 is a new oral antidiabetic agent that was effective in insulin-resistant diabetic animal models, including the KK mouse, the ob/ob mouse, and the Zucker fatty rat. CS-045 was not effective in the streptozocin-treated mouse, an insulin-deficient diabetic animal model. In fed KK mice, CS-045 lowered the plasma glucose levels in a dose-dependent manner after a single oral administration, and the hypoglycemic effect lasted for at least 18 h. In normal rats, however, plasma glucose levels were not changed after administration of CS-045. CS-045 when given chronically (2 wk) to diabetic KK and ob/ob mice as a 0.2% food admixture dramatically improved hyperglycemia, hyperinsulinemia, and hypertriglyceridemia to near-normal values and decreased plasma lactate, free fatty acid, and ketone body levels without reducing food intake or body weight. In the obese Zucker fatty rat, oral administration of CS-045 had a similar effect in lowering plasma glucose, insulin, triglyceride, free fatty acid, lactate, and ketone body levels. The CS-045-treated Zucker fatty rats showed increased glucose tolerance and decreased insulin secretion in response to oral glucose. After 9 days of treatment, insulin binding to adipocyte plasma membranes from both CS-045-treated Zucker fatty rats and KK mice was increased. Furthermore, 2-deoxyglucose uptake in CS-045-treated adipocytes was increased and the insulin dose-response curve was shifted to the left. These findings suggest that CS-045 increases not only insulin sensitivity but also insulin responsiveness. Based on its pharmacological profile, CS-045 is a new orally effective antidiabetic agent that may reduce abnormalities of glucose and lipid metabolism in obese and non-insulin-dependent diabetes mellitus patients with insulin resistance.

Acute hyperglycemia provides an insulin-independent inducer for GLUT4 translocation in C2C12 myotubes and rat skeletal muscle.

GLUT4 translocation and activation of glucose uptake in skeletal muscle can be induced by both physiological (i.e., insulin, nerve stimulation, or exercise) and pharmacological (i.e., phorbol ester) means. Recently, we demonstrated that high glucose levels may mimic the effects of phorbol esters on protein kinase C (PKC) and insulin receptor function (J Biol Chem 269:3381-3386, 1994). In this study, we tested whether the previously described effects of phorbol esters on translocation of GLUT4 in myotubes in culture and also in rat skeletal muscle might be mimicked by glucose. We found that stimulation of C2C12 myotubes with both insulin (10(-7) mol/l, 5 min) and glucose (25 mmol/l, 10 min) induces a comparable increase of the GLUT4 content in the plasma membrane. To test whether this effect occurs in intact rat skeletal muscle as well, two different model systems were used. As an in vitro model, isolated rat hindlimbs were perfused for 80 min with medium containing 6 mmol/l glucose +/- insulin (1.6 x 10(-9) mmol/l, 40 min) or 25 mmol/l glucose. As an in vivo model, acute hyperglycemia (> 11 mmol/l glucose, 20 min) was induced in Wistar rats by intraperitoneal injection of glucose under simultaneous suppression of the endogenous insulin release by injection of somatostatin. In both models, subcellular fractions were prepared from hindlimb skeletal muscle, and plasma membranes were characterized by the enrichment of the marker enzyme alpha 1 Na(+)-K(+)-ATPase.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of troglitazone on body fat distribution in type 2 diabetic patients.

OBJECTIVE: Troglitazone was recently reported to specifically promote the differentiation of pre-adipocytes into adipocytes in vitro in subcutaneous fat only, indicating a relation to insulin-resistance-improving action of troglitazone. To expand on this finding, we investigated at the clinical level how long-term administration of troglitazone influences the body fat distribution in type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Troglitazone (400 mg/day) was administered for 6 months to 30 type 2 diabetic patients whose glycemic control was poor. A total of 18 patients received diet therapy alone (in the single-treatment group, BMI 26.0 +/- 4.6, HbA1c 8.2 +/- 1.7%), and 12 patients concomitantly received glibenclamide (1.25-7.5 mg/day) (in the concomitant sulfonylurea group, BMI 25.4 +/- 4.7, HbA1c 9.2 +/- 1.2%). BMI, HbA1c, serum lipid level, and body fat distribution, which were determined by computed tomography (CT) scan at the umbilical level, were measured and compared before and after troglitazone treatment. RESULTS: During the 6-month troglitazone treatment, HbA1c levels decreased and BMI increased in both groups. As for body fat distribution in the single-treatment group, visceral fat area (VFA) decreased (from 118.3 +/- 54.3 to 101.1 +/- 50.8 cm2; P < 0.001), and subcutaneous fat area (SFA) increased (from 189.7 +/- 93.3 to 221.6 +/- 101.6 cm2; P < 0.001), resulting in a decrease in visceral/subcutaneous (V/S) ratio (from 0.74 +/- 0.48 to 0.50 +/- 0.32; P < 0.001). In the concomitant sulfonylurea group, VFA was unchanged (from 108.1 +/- 53.5 to 112.5 +/- 59.9 cm2), while SFA increased (from 144.6 +/- 122.0 to 180.5 +/- 143.5 cm2; P < 0.01), thereby decreasing the V/S ratio (from 0.91 +/- 0.46 to 0.77 +/- 0.44; P < 0.01). The serum triglyceride level and the area under glucose curve during the 75-g oral glucose tolerance test decreased significantly in the single-treatment group. CONCLUSIONS: According to our data, troglitazone appears to promote fat accumulation in the subcutaneous adipose tissue rather than in the visceral adipose tissue in mildly obese Japanese people with type 2 diabetes. This shift of energy accumulation from the visceral to subcutaneous adipose tissue may greatly contribute to the troglitazone-mediated amelioration of insulin resistance.

Troglitazone prevents the inhibitory effects of inflammatory cytokines on insulin-induced adipocyte differentiation in 3T3-L1 cells.

Tumor necrosis factor (TNF) is implicated in wasting syndromes and insulin resistance in chronic infection and obese-linked diabetes. TNF (10 ng/ml) inhibited adipocyte differentiation of 3T3-L1 cells, and in these TNF treated cells little insulin-stimulated glucose uptake was observed. Treatment of 3T3-L1 cells with troglitazone (1-10 microM) partially prevented this inhibitory effect of TNF on adipogenesis, and enhanced expression of C/EBP alpha and GLUT4, even in the presence of TNF. Troglitazone also prevented the inhibitory effects of interleukin-1, interleukin-6, and leukemia inhibitory factor, but not of transforming growth factor beta on adipocyte differentiation of 3T3-L1 cells. These effects might contribute to the antidiabetic effect of troglitazone in obese diabetic animals.

Antiinsulin receptor antibodies in an insulin-dependent diabetic may arise as autoantiidiotypes.

An insulin-requiring diabetic patient with intermittent periods of increased insulin requirements and insulin resistance was studied. The patient was found to have high titers of antiinsulin antibodies; subfractionation of the patient's serum revealed several populations of antiinsulin antibodies with differing affinities and titers for insulin. The ability of one of the insulin antibody fractions to bind [125I]iodoinsulin was markedly inhibited by the patient's serum (insulin depleted) and by purified total immunoglobulin G from which antiinsulin antibodies and insulin were removed. These findings suggested an antiidiotypic antibody in the patient's immunoglobulin G fraction reacting specifically with the antiinsulin antibody subfraction. Finally, the patient's serum contained an antiinsulin receptor antibody, as demonstrated by the ability of serum to specifically immunoprecipitate covalently labeled soluble insulin receptors. In conclusion, these results suggest that this patient generated a widespread polyclonal response to insulin, with the development of several populations of antiinsulin antibodies. An antiidiotypic antibody to a specific insulin antibody subfraction was present in the patient's serum which we believe had structural similarity to the binding site of the insulin molecule, accounting for the reactivity of the antiidiotypic antibody with the insulin receptor.

Combination treatment with troglitazone, an insulin action enhancer, and pravastatin, an inhibitor of HMG-CoA reductase, shows a synergistic effect on atherosclerosis of WHHL rabbits.

We examined whether improving insulin resistance augments the antiatherosclerotic effect of LDL reduction. Since WHHL rabbits show hyperinsulinemia and insulin resistance, we administered troglitazone (100 mg/kg), an insulin action enhancer, pravastatin sodium (50 mg/kg), an HMG CoA reductase inhibitor, and a combination of both drugs to 2-month-old WHHL rabbits for 32 weeks. As compared to the control, total cholesterol levels in the plasma and LDL were decreased significantly by 20% in the pravastatin and combination groups. Basal immunoreactive insulin levels and insulin index were decreased significantly by approximately 50% in the troglitazone and combination groups. Surface lesion area of atherosclerosis on the thoracic aorta was decreased significantly by 36% in the combination group and was less in the troglitazone group. Coronary atherosclerosis was decreased significantly by 39% in the combination group and was less in the pravastatin and troglitazone groups. The collagen content in the plaques was decreased in the troglitezone and combination groups and the extracellular lipid deposits were decreased in the pravastatin and combination groups. The incidence and severity of xanthomata in the digital joints were also decreased significantly in the three treated groups. In conclusion, the antiatherogenic effect of the combination treatment is stronger than that of the monotherapy.

Inhibition of oxidation of low density lipoprotein by troglitazone.

The effect of a new oral hypoglycemic agent troglitazone, (+/-)-5-[4-(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl-methoxy)benz yl]-2,4-thiazolidinedione as an antioxidant against the free radical-mediated oxidation of low density lipoprotein (LDL) was studied. The oxidation of LDL gives cholesteryl ester hydroperoxide and phosphatidylcholine hydroperoxide as major primary products. Troglitazone incorporated exogenously into LDL inhibited the oxidations of LDL induced by either aqueous or lipophilic peroxyl radicals and suppressed the formation of lipid hydroperoxides efficiently. Ascorbic acid added into the aqueous phase spared both endogenous alpha-tocopherol and troglitazone in LDL. It was also found by absorption spectroscopic and electron spin resonance (ESR) studies that troglitazone reacted rapidly with a galvinoxyl radical to give a chromanoxyl radical which gives the same ESR spectrum as alpha-tocopherol. This ESR spectrum disappeared rapidly when ascorbic acid was added into the system. These results show that troglitazone acts as a potent antioxidant and protects LDL from oxidative modification.

Studies on hindered phenols and analogues. 1. Hypolipidemic and hypoglycemic agents with ability to inhibit lipid peroxidation.

A series of hindered phenols were investigated as hypolipidemic and/or hypoglycemic agents with ability to inhibit lipid peroxidation. 1,3-Benzoxathioles (9 and 22), phenoxypentanoic acid (34), phenoxypentanol (35a), phenoxynonanol (35b), phenylchloropropionic acid having a chromanyl group (25), and a thiazolidine compound (27) derived from 25, all having a hindered phenol group, were prepared and examined. Compound 27 showed the expected biological properties in vivo and in vitro without any liver weight increase. Biological activities of the analogous thiazolidine compounds, 43-58, were compared. Thus, (+/-)-5-[4-[(6-hydroxy-2,5,7,8-tetramethylchroman-2-yl)methoxy]- benzyl]-2,4-thiazolidinedione (27) (CS-045) was found to have all of our expected properties and was selected as a candidate for further development as a hypoglycemic and hypolipidemic agent.

Molecular design, synthesis, and hypoglycemic activity of a series of thiazolidine-2,4-diones.

A series of imidazopyridine thiazolidine-2,4-diones were designed and synthesized from their corresponding pyridines. These compounds represent conformationally restricted analogues of the novel hypoglycemic compound rosiglitazone (5). The series was evaluated for its effect on insulin-induced 3T3-L1 adipocyte differentiation in vitro and its hypoglycemic activity in the genetically diabetic KK mouse in vivo. The structure-activity relationships are discussed. On the basis of the in vivo potency, 5-[4-(5-methoxy-3-methyl-3H-imidazo[4, 5-b]pyridin-2-ylmethoxy)benzyl]thiazolidine-2,4-dione (19a) was selected as the candidate for further studies in a clinical setting.

Differential susceptibility of resting CD4(+) T lymphocytes to a T-tropic and a macrophage (M)-tropic human immunodeficiency virus type 1 is associated with their surface expression of CD38 molecules.

Recent evidence has accumulated which definitively shows that chemokine receptors CCR5 and CXCR4 play an essential role as coreceptors for human immunodeficiency virus type 1 (HIV-1) infection. Flow cytometric analysis permitted us to detect CD38, a surface marker of early differentiation, as well as activation of T cells, on about half of healthy donor-derived CD4(+) T cells. In this study, we focused on the susceptibility of CD38(+) and CD38(-) subsets of CD4(+) T cells to HIV-1 infection with different coreceptor tropisms. About 20% of peripheral blood mononuclear cell-derived resting CD4(+) T cells were recovered into the CD38(+) subset fraction by panning with a monoclonal antibody to CD38. Most of the cells in this CD38(high) fraction also expressed CD45RA and CD62L at higher intensities compared with those of CD38(low) fraction. CCR5(+) T cells predominated in the CD38(-) subset, although cell surface expression of CD4 and CXCR4 was almost similar between both subsets. This difference was consistent with a significantly higher susceptibility of the CD38(-) subset to a macrophage (M)-tropic HIV-1 strain. In contrast, it was shown that a T-tropic strain of HIV-1 could replicate more efficiently in the CD38(+) subset, although viral adsorption rates were similar between both subsets. Thus, the differential susceptibility of CD4(+) T cells to M(-) and T-tropic HIV-1 was associated with their surface expression of CD38.

A specific T-cell subset with CD4+/CD38- markers derived from HIV-1 carriers induces apoptosis in healthy donor-derived T-lymphocytes.

Apoptosis is an important mechanism of human immunodeficiency virus type 1 (HIV-1)-induced T-cell depletion. Our recent findings revealed mitogenic stimulation-dependent apoptosis induction in healthy donor-derived peripheral blood T-lymphocytes after adsorption with defective HIV-1 particles through acquirement by a subset of CD4+/CD38- cells of specific killer function. Based on these in vitro observations, we have extended the significance of this killing activity of CD4+/CD38- cells directly derived from HIV-1 carriers. The CD4+/CD38- cells from HIV-1-positive individuals showed significantly higher cell-killing activities than those from HIV-1-negative donors by co-culture with allogeneic resting T-cells after mitogenic stimulation. Furthermore, most of the samples induced apoptosis in a Fas-dependent manner. Thus, it is suggested that HIV-1 infection-related apoptosis is triggered by inappropriate activation of a certain resting T-cell subset, presumably due to adsorption with HIV-1 particles.

Inherited primary hypothyroidism with thyrotrophin resistance in Japanese cats.

Mutant cats were developed with non-goitrous primary hypothyroidism. They were clinically characterized by severely retarded growth, mild anaemia and high mortality in the young. They responded markedly to thyroid hormone replacement. Thyroid glands in the mutants were normal in position but slightly reduced in size. Laboratory studies revealed low serum concentrations of thyroxine (T4) and tri-iodothyronine (T3), and increased serum concentrations of TSH. Administration of TRH induced no further increase in TSH. Administration of exogenous TSH after suppression of endogenous TSH by T3 did not increase the serum concentration of T4 in the mutants, in sharp contrast with the threefold increase in serum T4 observed in the normal litter-mates. These findings suggest that the underlying pathogenesis of this disorder is unresponsive to TSH. Moreover, we found that the mutants were transmitted in an autosomal recessive manner.

Suppression of hepatic gluconeogenesis in long-term Troglitazone treated diabetic KK and C57BL/KsJ-db/db mice.

The orally effective antidiabetic agent Troglitazone (CS-045) exerts hypoglycemic effects in various insulin-resistant obese and/or diabetic animals. Since increased hepatic gluconeogenesis is a major cause of hyperglycemia in these diabetic animals, we evaluated the effect of long-term Troglitazone treatment on hepatic gluconeogenesis. Troglitazone was administered for 7 days to normal ddY mice, diabetic KK mice, diabetic C57BL/KsJ-db/db mice, and its heterozygote, db/+ mice, as a 0.1% or 0.2% food admixture. Troglitazone significantly decreased plasma glucose in diabetic KK and db/db mice, but not in normal ddY and db/+ mice. 14C incorporation into blood glucose from NaH14CO3 was measured to assess hepatic gluconeogenesis in diabetic KK and normal ddY mice. Hepatic gluconeogenesis was significantly increased in diabetic KK mice (P < .01) as compared with normal mice, and was significantly suppressed (P < .05) after 7 days of Troglitazone treatment (approximately 200 mg/kg/d). Glucose-6-phosphate (G6P) and fructose-6-phosphate (F6P) were significantly decreased but fructose-1,6-bisphosphate (FBP) was not significantly increased in the liver of diabetic db/db mice treated with Troglitazone for 7 days (approximately 80 mg/kg/d) as compared with control db/db mice. These changes in G6P, F6P, and FBP corresponded with the activity of fructose-1,6-bisphosphatase (Fru-1,6P2ase) and 6-phosphofructo-1-kinase (6-PF-1K), which determined the content of F6P and FBP. Namely, Fru-1,6P2ase was significantly decreased in Troglitazone-treated db/db mice as compared with control mice, whereas 6-PF-1K activity was not affected by Troglitazone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of CS-045, a new oral antidiabetic agent, II. Effects on glycemic control and pancreatic islet structure at a late stage of the diabetic syndrome in C57BL/KsJ-db/db mice.

Antidiabetic effects of CS-045 were evaluated in 5-month-old C57BL/KsJ-db/db mice (db/db). CS-045 administered for 3 weeks to diabetic db/db mice as a 0.2% food admixture improved hyperglycemia (855 +/- 25 v 298 +/- 62 mg/dL, P less than .01) and glucose intolerance, and lowered plasma triglyceride (299.6 +/- 28.7 v 76.3 +/- 20.7 mg/dL, P less than .01) and free fatty acid (FFA) levels (1.16 +/- 0.14 v 0.57 +/- 0.07 mEq/L, P less than .01). Food intake was not changed, while a small but significant increase in body weight was observed in CS-045-treated mice. Plasma insulin levels gradually increased after 5 days of CS-045 treatment, and a nonsignificant increase was observed in plasma insulin levels after 3 weeks (1.85 +/- 0.50 v 4.54 +/- 1.47 mg/mL). In contrast, the plasma glucagon levels decreased after 3 weeks of CS-045 treatment. Histological examination by aldehyde-fucshin staining demonstrated that pancreatic beta cells in CS-045-treated db/db mice were heavily regranulated, whereas most of the beta cells were extensively degranulated in nontreated db/db mice. The heavily regranulated state of beta cells was also compatible with an increase in pancreatic insulin content in CS-045-treated db/db mice. Electron microscopic analysis showed a well-developed endoplasmic reticulum and the accumulation of much amorphous structural material in the intracisternal space of beta cells from CS-045-treated db/db mice, which were suggestive of an increase in insulin synthesis. Moreover, CS-045 treatment decreased exocrine-containing islets, which was associated with the islets' degeneration process. Immunohistochemical staining of islets showed that CS-045 treatment normalized the distribution pattern of endocrine cells in the islets of db/db mice, reflected by a predominantly peripheral location of alpha and delta cells.(ABSTRACT TRUNCATED AT 250 WORDS)