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Biomedical subjects

T Doi

Publications and source records attributed to T Doi.

At least 55 records · Page 3Linked to original sources

A case of successful management of portosystemic shunt with autosomal dominant polycystic kidney disease by balloon-occluded retrograde transvenous obliteration and partial splenic embolization.

We describe a patient with autosomal dominant polycystic kidney disease who was successfully managed for severe abdominal distension, impaired liver function and a portosystemic shunt by interventional therapies. The patient's intra-hepatic portal vein was compressed and narrowed by multiple liver cysts, which resulted in a decrease of the portal blood flow and portal hypertension due to a huge gastro-renal shunt These haemodynamic changes were assumed to contribute to insufficient protein synthesis in the liver. Therefore, we first repeatedly performed minocycline hydrochloride instillations to treat the multiple liver cysts. Then, we conducted a partial splenic embolization to prevent elevation of the portal vein pressure prior to balloon-occluded retrograde transvenous obliteration which was performed to increase the portal blood flow. The portal blood flow markedly increased, and protein synthesis in the liver also recovered and the clinical symptoms improved. The patient has been monitored for more than two years up to the present and her liver function parameters have remained within the normal range. Renal insufficiency is known to be a major prognostic factor in autosomal dominant polycystic kidney disease. In some cases, however, liver involvement with multiple cysts may result in a fatal outcome. In such cases, interventional therapies, as provided to this patient, should be considered.

Cysts↗

Effect of transjugular intrahepatic portosystemic shunt formation on portal hypertensive gastropathy and gastric circulation.

OBJECTIVES: The aim of this study was to investigate the effect of a transjugular intrahepatic portosystemic shunt (TIPS) on portal hypertensive gastropathy (PHG) and gastric hemodynamics. METHODS: A total of 16 patients with cirrhosis and portal hypertensive gastropathy were prospectively studied. Of these, 12 patients underwent TIPS for esophageal varices and four for refractory ascites. Gastric mucosal blood flow (GMBF) was assessed by laser Doppler flowmeter, and total blood flow (TBF) in submucosa and mucosa by near-infrared endoscopy. Portal venous pressure was obtained by a transducer during the TIPS procedure. The severity of portal hypertensive gastropathy was classified as none, mild, or severe. The examinations were performed before and 2 wk after the procedure. RESULTS: TIPS significantly reduced portal venous pressure. PHG improved in all four patients with severe PHG and in five of 12 patients with mild PHG after treatment. Gastric mucosal blood flow increased from 49.0 to 55.6 ml/min/100 g after TIPS. In contrast, TBF decreased from 0.35/s to 0.27/s after treatment. Liver function tests showed no significant changes before and after the procedure. CONCLUSIONS: It is considered that TIPS may have a beneficial effect on PHG at least for a short time. The mechanism by which PHG improves may be closely related to the improvement of the injured gastric perfusion in cirrhotic patients with PHG.

Esophageal and Gastric Varices↗

Study on PDGF receptor beta pathway in glomerular formation in neonate mice.

The assembly of vascular endothelial cells (ECs) and smooth muscle cells is a critical event in the development of the cardiovascular system. Although the role of ECs in this event has been studied intensively, the cross-talk between the two cell components remains poorly understood. In this study, we blocked platelet-derived growth factor receptor (PDGFR) pathways in mice by antagonistic rat monoclonal antibody APB5 against murine PDGFR-beta and examined glomerular capillary formation.

Aging↗

Intestinal satiety protein apolipoprotein AIV is synthesized and regulated in rat hypothalamus.

Apolipoprotein AIV (apo AIV) is a satiety protein secreted by the small intestine. We demonstrate for the first time that apo AIV protein and apo AIV mRNA are present in rat hypothalamus, a site intimately involved in the integration of signals for regulation of food intake and energy metabolism. We further characterized the regulation of hypothalamic apo AIV mRNA levels. Food-deprived animals showed a pronounced decrease in gene expression of apo AIV in the hypothalamus, with a concomitant decrease in the jejunum. Refeeding fasted rats with standard laboratory chow for 4 h evokes a significant increase of apo AIV mRNA in jejunum but not in hypothalamus. However, lipid refeeding to the fasted animals restored apo AIV mRNA levels both in hypothalamus and jejunum. Intracerebroventricular administration of apo AIV antiserum not only stimulated feeding, but also decreased apo AIV mRNA level in the hypothalamus. These data further confirm the central role of apo AIV in the regulation of food intake.

Animals↗

Effect of leptin on intestinal apolipoprotein AIV in response to lipid feeding.

We determined apolipoprotein AIV (apo AIV) content in intestinal epithelial cells using immunohistochemistry when leptin was administered intravenously. Most of the apo AIV immunoreactivity in the untreated intestine was located in the villous cells as opposed to the crypt cells. Regional distribution of apo AIV immunostaining revealed low apo AIV content in the duodenum and high content in the jejunum that gradually decreases caudally toward the ileum. Intraduodenal infusion of lipid (4 h) significantly increased apo AIV immunoreactivity in the jejunum and ileum. Simultaneous intravenous leptin infusion plus duodenal lipid infusion markedly suppressed apo AIV immunoreactivity. Duodenal lipid infusion increased plasma apo AIV significantly (measured by ELISA), whereas simultaneous leptin infusion attenuated the increase. These findings suggest that leptin may regulate circulating apo AIV by suppressing apo AIV synthesis in the small intestine.

Animals↗

Upregulation of H(+)-peptide cotransporter PEPT2 in rat remnant kidney.

The progression of renal damage resulting from reduced nephron mass has been extensively studied in the 5/6 nephrectomized rat. However, reabsorption of small peptides and D-glucose across the renal proximal tubule in this model remains poorly understood. In this study, we examined the alterations of H(+)-peptide cotransporters (PEPT1 and PEPT2) and Na(+)-D-glucose cotransporters (SGLT1 and SGLT2) in chronic renal failure. Two weeks after surgery, H(+)-dependent [(14)C]glycylsarcosine uptake by the renal brush-border membrane vesicles isolated from 5/6 nephrectomized rats was significantly increased compared with that from sham-operated controls. Kinetic analysis revealed that the maximum velocity value for [(14)C]glycylsarcosine uptake by the high-affinity-type of peptide transporter was increased threefold by 5/6 nephrectomy, without significant changes in the apparent Michaelis-Menten constant value. Competitive PCR analyses indicated that the expression of PEPT2 mRNA was markedly increased in the remnant kidney, but PEPT1, SGLT1, and SGLT2 mRNA levels showed no significant changes. These findings indicated that the high-affinity-type H(+)-peptide cotransport activity is upregulated by 5/6 nephrectomy, accompanied by the increased expression of PEPT2. The upregulation of PEPT2 expression would result in an increase in reabsorption of small peptides and peptide-like drugs across the brush-border membranes in chronic renal failure.

Animals↗

Development and prevention of advanced diabetic nephropathy in RAGE-overexpressing mice.

Vascular complications arising from multiple environmental and genetic factors are responsible for many of the disabilities and short life expectancy associated with diabetes mellitus. Here we provide the first direct in vivo evidence that interactions between advanced glycation end products (AGEs; nonenzymatically glycosylated protein derivatives formed during prolonged hyperglycemic exposure) and their receptor, RAGE, lead to diabetic vascular derangement. We created transgenic mice that overexpress human RAGE in vascular cells and crossbred them with another transgenic line that develops insulin-dependent diabetes shortly after birth. The resultant double transgenic mice exhibited increased hemoglobin A(1c) and serum AGE levels, as did the diabetic controls. The double transgenic mice demonstrated enlargement of the kidney, glomerular hypertrophy, increased albuminuria, mesangial expansion, advanced glomerulosclerosis, and increased serum creatinine compared with diabetic littermates lacking the RAGE transgene. To our knowledge, the development of this double transgenic mouse provides the first animal model that exhibits the renal changes seen in humans. Furthermore, the phenotypes of advanced diabetic nephropathy were prevented by administering an AGE inhibitor, (+/-)-2-isopropylidenehydrazono-4-oxo-thiazolidin-5-ylacetanilide (OPB-9195), thus establishing the AGE-RAGE system as a promising target for overcoming this aspect of diabetic pathogenesis.

Animals↗

Effect of TAK-637, a tachykinin NK1-receptor antagonist, on lower urinary tract function in cats.

The effect of TAK-637 ((aR,9R)-7-[3,5-bis(trifluoromethyl)benzyl]-8,9,10,11-tetrahydro-9-methyl-5-(4-methylphenyl)-7H[1,4]diazocino[2,1g][1,7]naphthyridine-6,13-dione), a tachykinin NK1-receptor antagonist, on lower urinary tract function was investigated in cats. TAK-637 (0.1, 0.3, 1 and 3 mg/kg, i.v.) produced a dose-dependent increase in bladder capacity without any significant reduction in voiding efficiency in decerebrate cats. The maximal increase in bladder capacity was 94%. By contrast, oxybutynin at 1 and 3 mg/kg (i.v.) produced a 18% and 35% increase in bladder capacity, respectively, with a 47% and 45% reduction in voiding efficiency. TAK-637 (3 mg/kg, i.v.) did not inhibit the micturition reflex induced by electrical stimulation of the rostral brainstem near the locus coeruleus, indicating that it does not impair the well-organized micturition reflex (bladder contraction and urethral relaxation). These results suggest that TAK-637 increases bladder storage capability without inhibiting the voiding function of the lower urinary tract, presumably by inhibiting the afferent pathway of the micturition reflex, rather than the efferent pathway.

Animals↗

Influence of the presence of OB-Re on leptin radioimmunoassay.

Leptin, a hormone derived from adipose tissue, regulates energy homeostasis and body weight. In the mouse, serum leptin levels, when measured by radioimmunoassay (RIA), increase by a factor of more than 50 times during pregnancy, compared with those in the non-pregnant state. It is well known that mouse placenta produces the secretory isoform of the leptin receptor, OB-Re. In order to investigate the issue of whether serum leptin levels are actually increased during pregnancy or whether the increased OB-Re concentration plays a role in this phenomenon, serum leptin levels were determined by the immunoprecipitation of leptin using anti-leptin antibody, and were found to be increased only by about ten times during pregnancy. To investigate the influence of OB-Re on leptin measurement by the RIA procedure, serum leptin levels were measured by the RIA after the addition of OB-Re to the serum. The apparent values of leptin levels increased in parallel with the amount of OB-Re added to the serum. Leptin levels, as determined by the RIA, might therefore provide artificially high values when serum levels of the secretory form of OB-R are high, in cases, for example, such as the last period of pregnancy in mice.

Analysis of Variance↗

Association of plasma homocysteine concentrations with carotid atherosclerosis in elderly Japanese.

OBJECTIVE: Homocysteine (Hcy) is a sulfhydryl amino acid. Its precursor, the essential amino acid methionine, is derived from dietary protein; recently a number of studies have suggested its relation to atherosclerosis. The present study was performed to clarify the relation between the plasma Hcy concentration and sclerotic lesions of the common carotid arteries. METHODS AND PATIENTS: We evaluated sclerotic lesions of common carotid arteries by ultrasonography in 120 elderly in-patients (77+ /- 9 years), and studied the relationship of the known risk factors for atherosclerosis including plasma Hcy. An ultrasonograph and 7.5 MHz linear type B-mode probe were used by a specialist to evaluate sclerotic lesions of the common carotid arteries. Blood was drawn from the patients while fasting for determination of plasma Hcy. Plasma Hcy concentrations were determined using a high-performance liquid chromatography assay. RESULTS: Logistic regression analysis using IMT as an object variable, adjusted by various risk factors including the plasma Hcy concentration, revealed that the relative risk in the group combining the second and the third highest Hcy groups was 6.49 (95% confidence interval (CI): 1.95-21.9) compared with the first group and the plaque presence showed a relative risk of 4.45 (95% CI: 1.53-12.9). CONCLUSION: The findings of this study confirmed that observations of an association between plasma Hcy concentration and common carotid atherosclerosis in Western populations is also present among the elderly Japanese.

Aged↗

An association between an antibody against Chlamydia pneumoniae and common carotid atherosclerosis.

OBJECTIVE: Chlamydia pneumoniae (C. pneumoniae) is an important pathogen for infections of the respiratory tract, and there are recently also a number of reports suggesting its relation with atherosclerosis. This study was performed to clarify the relation between C. pneumoniae infection and sclerotic lesions of the common carotid arteries. METHODS AND PATIENTS: We evaluated sclerotic lesions of common carotid arteries by ultrasonography in 147 in-patients (mean age, 70 years; 95% confidence interval, 68-72) in the internal medicine ward, and studied the relation of the known risk factors for atherosclerosis including C. pneumoniae infection. An ultrasonograph and 7.5 MHz linear type B-mode probe were used by a specialist to evaluate sclerotic lesions of common carotid arteries. C. pneumoniae infection was determined by measuring anti-C. pneumoniae IgG specific antibody level (IgG index) using enzyme-linked immunosorbent assay (ELISA) method with serum of fasting blood, which had been preserved at -70 degrees C. RESULTS: IgG index (p=0.0263), from multiple regression analysis using various risk factors as explanatory variables, was a significant independent contributing factor (R2=0.3465, p<0.0001) along with known risk factors such as male (p=0.0289), age (p=0.0007), Brinkman index (p=0.0067), hypertension (p=0.0443) and T-Chol (p=0.0220). CONCLUSION: This study confirmed that the observations of an association between antibody against C. pneumoniae and common carotid atherosclerosis in Western nations is also present in Japan. Our results suggests that C. pneumoniae infection is also an important risk factor for common carotid atherosclerosis.

Adult↗

Proinflammatory cytokines regulate the gene expression of hyaluronic acid synthetase in cultured rabbit synovial membrane cells.

To elucidate the mechanism of accumulation and fragmentation of hyaluronic acid (HA) under inflammatory conditions, we investigated the effect of proinflammatory cytokines on hyaluronic acid synthetase (HAS) mRNA expression using cultured rabbit synovial membrane cells. HASs mRNA levels were determined by real-time PCR. HAS2 mRNA expression was maximally enhanced 3.3- and 2.8-fold after 3-hour stimulation with IL-1beta (1 ng/ml) and after 1-hour stimulation with TNF-alpha (10 ng/ml). HAS3 mRNA expression was increased by a maximum of 4.3 times after 3-hour stimulation with IL-1beta (10 ng/ml), whereas 1-hour stimulation with TNF-alpha (10 ng/ml) and IFN-gamma (10 ng/ml) induced around a 2.5-fold increase in HAS3 mRNA. Although IFN-gamma (1-100 ng/ml) alone showed little effect on HAS2 mRNA expression, the effect was synergized by combined with both IL-1beta and TNF-alpha, substantially increasing HAS2 mRNA expression. These results suggest that proinflammatory cytokines regulate the HAS expression, and consequently may contribute to the accumulation and fragmentation of HA.

Animals↗

Reference values and limited serological survey for the Iriomote cat in Japan.

Clinical investigations and hematological, serum biochemical, and serological surveys were carried out on 11 male and 6 female Iriomote cats (Felis iriomotensis) in Japan. Examined Iriomote cats were considered clinically healthy by the inspection for the general physical conditions. However, urinalysis suggested the inflammation of the urinary tract in all the cats. Antibody for feline panleukopenia virus was positive in one of the examined Iriomote cats, which suggested a previous infection.

Animals↗

Expression of basic helix-loop-helix proteins in the glomeruli.

BACKGROUND: Basic helix loop helix (bHLH) proteins play a critical role in the differentiation of not only striated muscle cells but also adipocytes, neuron cells and smooth muscle cells. Previous studies have established in vitro mouse mesangial cells (MCs) to maintain the differentiated smooth muscle phenotype. MATERIALS AND METHODS: The purpose of the present study was to clone bHLH proteins from these MCs using the primers designed from a homologous sequence specific to bHLH, and to analyze the presence of bHLH proteins in normal kidney in vivo. From the cloning of MCs in vitro, we identified myf5 and herculin mRNA but not myoD. The expression of bHLH proteins in vivo was examined by immunohistochemistry with each specific antibody. RESULTS: The MCs in newborn mice possessed Id but did not express either protein herculin or myoD. On the other hand, mature MCs expressed both myf5 and herculin. The Id protein disappeared in mature glomeruli. CONCLUSION: These results suggest that bHLH proteins are an important factor for mature MCs in vivo.

Aging↗

The contribution of mesangial cell proliferation to progressive glomerular injury.

Mesangial cell proliferation is a general characteristic of a variety of glomerular diseases. Therefore, an understanding of the regulatory mechanism is important for treatment of glomerular diseases. The present review shows that the growth arrest gene 6 (Gas 6) is a new autocrine growth factor of mesangial cells and that warfarin inhibits mesangial cell proliferation by inhibiting the gamma-carboxylation of Gas 6 in vitro and in vivo. The present findings also show that a vitamin D analog (22-oxa-calcitriol) is a new growth regulator of mesangial cells in vitro and in vivo. These findings indicate that these compounds have considerable potential for therapeutic use in the treatment of progressive glomerular disease.

Animals↗

[Regulatory factors for changing laboratory data before and after dialysis therapy].

The proper assessment of laboratory data in dialysis patients is important to maintain the effectiveness of therapy. The factors for regulating laboratory data in dialysis patients are as follows: 1. abnormal data associated with renal dysfunction(uremic state). 2. changes in laboratory data related to dialysis therapy. 3. changes in data related to biocompability for dialysis. 4. changes in data related to movement of fluid between different compartments. 5. changes in data related to different methods of therapy. The goal of this discussion is to describe the general principles for the assessment of laboratory data in dialysis patients, to offer a good therapy and to provide the best outcome in order to improve the ADL and QOL in the patients.

Biocompatible Materials↗