Short polymers of arginine rapidly translocate into vascular cells: effects on nitric oxide synthesis.

The present study was designed to determine the efficiency of translocation of short polymers of arginine into vascular smooth muscle cells (VSMC) and to determine their effect on nitric oxide (NO) synthesis. Immunostaining revealed that heptamers of L-arginine (R7) rapidly translocated into the VSMC. This rapid transport was not observed with shorter polymers of L-arginine (R5) nor heptamers of lysine (K7). Translocation of R7 was not inhibited by the addition of free L-arginine into the media. When cells were transiently pretreated with R7 or a nonamer of arginine (R9), NO(2) production from cytokine stimulated VSMC was significantly increased, whereas incubation with R5 and K7 had no effect. Short polymers of arginine not only have a unique ability of rapid VSMC translocation but once internalized enhance NO production. Heptamers (or larger polypeptides) of arginine may be useful in therapy to enhance NO production in the vascular system.     

Milk casein-derived tripeptides, VPP and IPP induced NO production in cultured endothelial cells and endothelium-dependent relaxation of isolated aortic rings

Milk casein-derived tripeptides, valyl prolyl proline (VPP), and isoleucyl prolyl proline (IPP) inhibit angiotensin-converting enzyme (ACE) and both fermented milk and proteolytic hydrolysates of milk casein containing these peptides exert blood pressure-lowering effects in animals and humans. On the top of these results, we have recently reported that the hydrolysate of milk casein containing both VPP and IPP improved the vascular endothelial function of subjects with stage I hypertension, enforcing us to elucidate the mechanism of the improvement of endothelial dysfunction by these peptides. For this purpose, we examined the effect of VPP and IPP on induction of nitric oxide (NO) production using cultured vascular endothelial cells and isolated arterial vessels. When both VPP and IPP were added to the medium of cultured endothelial cells at final concentrations of more than 100 nmol/l, the NO _x (NO₂ and NO₃) concentration in the medium was significantly higher than that of the control. Moreover, both VPP and IPP induced endothelium-dependent relaxation of isolated aortic rings, and these effects were inhibited by NO synthase inhibitors, K channel inhibitors, and bradykinin B2 receptor antagonists. These lines of results suggested that both VPP and IPP induced production of vasodilative substances including NO.     

Bone lesions in elderly multiple myeloma

We investigated the incidence of bone lesions in elderly cases of multiple myeloma (MM) and the course of those lesions, and also evaluated the relationships of skeletal symptoms with prognostic factors, and prognosis. The subjects were 146 patients, aged 65 years or more (median age 74, range 65-97 year), who were admitted to 11 institutions between January, 1988 and December, 1997. They consisted of 64 men and 82 women. The disease type was IgG type in 88 patients, IgA type in 37 patients, Bence-Jones (BJ) type in 17 patients, IgD type in three patients, and non-secretory type in one patient. Bone lesions in elderly MM patients were compared with those in 65 non-elderly MM patients. Skeletal symptoms were noted in 104 patients, and bone pain in 75 patients at the time of diagnosis. The bone lesions were evaluated as only osteolytic lesions in 26 patients, osteolytic lesions + osteoporosis in 23 patients, only osteoporosis in 2 patients and pathologic bone fractures in 53 patients. The occurrence rate of osteoporosis plus osteolytic lesion was higher in elderly patients (63.5%) than that in non-elderly patients (NE-MM group) (28.3%) (p < 0.0001). The bone lesions were most often observed in lumbar vertebrae (58.7%), cranial bone (56.7%), thoracic vertebrae (40.4%) and ribs (27.9%). The occurrence rate of bone lesion in lumbar vertebrae was higher in elderly patients (58.7%) than that in non-elderly patients (22.6%) (p < 0.0001). The life activities were limited in 71 patients because of the bone lesions. The relationship between the prognostic factors of MM and bone lesions was evaluated. There was a significant difference in the serum Ca level between patients with and without bone pain (P < 0.0001) and between those with and without pathologic bone fracture (P < 0.01). There was a significant difference in the appearance rate of plasma cells in the bone marrow between the patients with and without bone lesions (P < 0.05), between those with and without bone pain (P < 0.01), and between those with and without pathologic fracture (P < 0.05). There was a significant difference in the serum beta 2-microglobulin level between the patients with and without bone pain, and between those with and without pathologic fracture. There were no significant differences in survival times between elderly MM patients with and without bone lesions, bone pain and pathological bone fractures, while significant differences of survival times were found between non-elderly MM patients with and without bone lesions, bone pain and pathological bone fractures (P < 0.05, each). These data suggest that there are some differences in bone lesions between elderly and non-elderly MM patients.     

Association between activating mutations of calcium-sensing receptor and Bartter's syndrome

Bartter's syndrome is a heterogeneous disorder characterised by deficient renal reabsorption of sodium and chloride, and hypokalaemic metabolic alkalosis with hyper-reninaemia and hyperaldosteronaemia. Mutations in several ion transporters and channels have been associated with the pathogenesis of Bartter's syndrome. We describe two hypocalcaemic patients with deficient parathyroid hormone secretion who also showed characteristics of Bartter's syndrome. We found activating mutations of the gene for the calcium-sensing receptor (CASR) in both patients. Activation of this calcium-sensing receptor inhibits the activity of a renal outer-medullary potassium channel that is mutated in type 2 Bartter's syndrome. We therefore suggest that some activating mutations of CASR could provide new mechanisms for the development of Bartter's syndrome.     

Novel nonsense mutation in the platelet glycoprotein Ibbeta gene associated with Bernard-Soulier syndrome

Bernard-Soulier syndrome (BSS) is an autosomal recessive bleeding disorder caused by quantitative or qualitative abnormalities in the glycoprotein (GP) Ib/IX/V complex, the platelet receptor for von Willebrand factor. This complex is composed of four subunits, GPIbalpha, GPIbbeta, GPIX, and GPV, and the coordinated assembly of GPIbalpha, GPIbbeta, and GPIX is required for the efficient surface expression of a functional complex. We report here a novel nonsense mutation of the GPIbbeta gene associated with BSS. Flow cytometric analysis of the patient's platelets showed markedly reduced GPIbalpha and absent GPIX surface expression. Immunoblot analysis of solubilized platelets showed that a small amount of GPIbalpha was detected; however, GPIbbeta and GPIX were undetectable. DNA sequencing analysis revealed a novel nonsense mutation of the GPIbbeta gene that converts Trp (TGG) to a stop codon (TAG) at residue 123. Transient transfection studies revealed that the mutant GPIbbeta polypeptide was not detected in the transfected 293T cells, suggesting that null expression of the mutant GPIbbeta impairs expression of the GPIbalpha and GPIX subunits and results in a BSS phenotype in the patient.     

Focal nodular hyperplasia-like lesion with venous washout in alcoholic liver cirrhosis

A case of 22 mm hypervascular nodule in segment two of the liver but without hepatitis B or C virus infection in a 32-year-old Japanese woman with a history of alcohol abuse is presented. Imaging studies such as contrast-enhanced ultrasound, computed tomography and magnetic resonance imaging showed hypervascularity in the early phase and venous washout in the late phase. Histologically, stellate scar-like fibrous septa, pericellular fibrosis, fatty change, neutrophilic infiltration, slight increase of cell density, and diffuse capillarization of the sinusoids together with small unpaired arteries were observed. The nodule was diagnosed as focal nodular hyperplasia-like lesion in alcoholic liver cirrhosis.     

Ultrasonographically assessed carotid atherosclerosis in Japanese type 2 diabetic patients: Role of nonesterified fatty acids

The aim of the present study was to evaluate the association of carotid atherosclerosis (intimal-medial thickness [IMT] in plaque-free segments and carotid stenosis in plaque segments) with serum nonesterified fatty acids (NEFA) in diabetic and nondiabetic patients. Fifty-one nonobese nonhypertensive Japanese type 2 diabetic patients aged 38 to 83 years (60.0 +/- 1.5 years, mean +/- SEM) and 23 age-matched (60.4 +/- 2.2 years, P =.439; range, 36 to 74 years) and sex-matched nondiabetic subjects were examined. The duration of diabetes was 9.6 +/- 1.0 years. Body mass index (BMI), blood pressure (systolic pressure, diastolic pressure), glycosylated hemoglobin (HbA(1c)), and fasting concentrations of plasma glucose, serum lipids (triglycerides, total, and high-density lipoprotein [HDL] cholesterol, low-density lipoprotein [LDL] cholesterol) and serum NEFA were measured. Using high-resolution B-mode ultrasound scan, we measured IMT in plaque-free segments of bilateral common carotid arteries, and the mean of IMT in 2 vessels was used for the analysis. Furthermore, we calculated the degree of stenosis in plaque segments of bilateral common carotid arteries. The degree of carotid stenosis was expressed as a percentage ratio between the area of plaque and that of the lumen using the formula (Lumen Area - Residual Lumen) x 100. Both the areas were automatically measured by the system on a frozen transverse scanning plane at the site of maximal narrowing. When 2 or more plaques were present in the vessel, only that causing the greatest degree of stenosis was considered for analysis. Univariate regression analyses showed that mean IMT in plaque-free segments was positively correlated with age (r =.498, P =.0004) and NEFA (r =.354, P =.0188) in type 2 diabetic patients. The degree of stenosis was positively correlated to age (r =.422, P =.0028), duration of diabetes (r =.313, P =.0268) and NEFA (r =.540, P =.0003) in diabetic patients. Other variables, including BMI and lipid profile, were not associated both with mean IMT in plaque-free segments and the degree of stenosis in plaque segments in our diabetic patients. Multiple regression analyses showed that mean IMT in plaque-free segments was independently associated with age (P =.0003, F = 15.2), which explained 26.1% of the variability of IMT in our diabetic patients. The degree of stenosis was independently predicted by NEFA (P =.0047, F = 8.9), which explained 17.2% of the variability of the carotid stenosis in our diabetic patients. In contrast, mean IMT in plaque-free segments was positively correlated to age in nondiabetic subjects (r =.450, P =.0347). There was, however, no relationship between the degree of stenosis and the variables, including age and NEFA, in nondiabetic subjects. These results indicate that the factors contributing to IMT in plaque-free segments and the degree of carotid stenosis in plaque segments are different in nonobese nonhypertensive Japanese type 2 diabetic patients. IMT in plaque-free segments was independently associated with age both in nondiabetic and diabetic subjects, whereas the serum NEFA level independently predicted the degree of stenosis in plaque segments in our diabetic patients, while not in nondiabetic subjects. Thus, NEFA is considered to be one of the new risk factors responsible for the progression of carotid atherosclerosis in nonobese nonhypertensive Japanese type 2 diabetic patients.     

Portacaval shunt causes apoptosis and liver atrophy in rats despite increases in endogenous levels of major hepatic growth factors

BACKGROUND/AIMS: The response to the liver damage caused by portacaval shunt (PCS) is characterized by low-grade hyperplasia and atrophy. To clarify mechanisms of this dissociation, we correlated the expression of 'hepatotrophic factors' and the antihepatotrophic and proapoptotic peptide, transforming growth factor (TGF)-beta, with the pathologic changes caused by PCS in rats. METHODS: PCS was created by side-to-side anastomosis between the portal vein and inferior vena cava, with ligation of the hilar portal vein. Hepatic growth mediators were measured to 2 months. RESULTS: The decrease in the liver/body weight ratio during the first 7 days which stabilized by day 15, corresponded to parenchymal cell apoptosis and increases in hepatic TGF-beta concentration that peaked at 1.4 x baseline at 15 days before returning to control levels by day 30. Variable increases in the concentrations of growth promoters (hepatocyte growth factor, TGF-alpha and augmenter of liver regeneration) also occurred during the period of hepatocellular apoptosis. CONCLUSIONS: The development of hepatic atrophy was associated with changes in TGF-beta concentration, and occurred despite increased expression of multiple putative growth promoters. The findings suggest that apoptosis set in motion by TGF-beta constrains the amount of hepatocyte proliferation independently from control of liver volume.     

Hepatitis e virus infection in fulminant hepatitis patients and an apparently healthy population in Bangladesh

This is the first study comparing hepatitis E virus (HEV) infection in Bangladesh in fulminant hepatitis (FH) patients presumed to have a viral cause and in the apparently healthy population. Sera from 22 FH patients were analyzed for antibodies to hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C and D viruses, and HEV and for hepatitis B surface antigen (HBsAg). Anti-HEV immunoglobulin M (IgM) was detected in the sera of 63.6% of patients, whereas 35.7% were positive for HBsAg. A high prevalence of HEV infection (83.3%) was noted in the HBV carriers. Serum samples from 273 apparently healthy individuals were tested for antibodies to HAV and HEV. Anti-HEV IgM was detected in 7.3% of the samples. The seroprevalence of HAV differed from that of HEV in the same population because all samples were negative for anti-HAV IgM. These data indicate that HEV infection is highly endemic in Bangladesh.