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Biomedical subjects

Y Kuroda

Publications and source records attributed to Y Kuroda.

At least 397 records · Page 22Linked to original sources
PubMed1996

Centrifugal pump-assisted venous bypass between the superior mesenteric vein and the umbilical vein during portal vein resection.

We describe herein our method of performing centrifugal pump-assisted venous bypass between the superior mesenteric vein and the umbilical vein, developed with the aim of preventing congestion of the small intestine and promoting strong and constant hepatic blood flow during portal vein resection. By using this bypass method, portal vein resection and reconstruction was able to be carried out with ease and safety in six patients undergoing surgery for a pancreatic mass or cancer. No coagulation abnormalities, thrombocytopenia, leukocytopenia, severe liver dysfunction, or portal vein thrombosis developed in any of the patients postoperatively. Thus, we highly recommend this simple and reliable method of bypass when portal vein resection is being performed.

Carcinoma, Acinar Cell↗
PubMed1996

Absence of the inferior vena cava in a patient with omphalocele: two-dimensional echocardiographic and cineangiographic findings.

We report an unusual form of absence of the inferior vena cava (IVC) in a patient with a repaired omphalocele. Two sets of bilateral paravertebral veins served as the channels of systemic venous return from the lower half of the body. These veins were narrower than typical azygos or hemiazygos continuation in the absence of the IVC, with the result that a catheter from the femoral vein could not reach the right atrium (RA). Other associated venous-side anomalies were present, including a chamber between the hepatic vein (HV) and RA, narrowing and angulation at the junction between the HV and the chamber, and a subaortic innominate vein. All these anomalies were demonstrated by two-dimensional and color Doppler echocardiography. The recognition of these venous anomalies is important for cardiac catheterization or IVC cannulation for cardiopulmonary bypass in patients with omphalocele.

Adult↗
PubMed1996

IgA nephropathy presenting clinicopathological features of acute post-streptococcal glomerulonephritis.

UNLABELLED: A 5-year-old Japanese girl was affected with acute nephritis. The patient had hypo-complementaemia and an elevation of anti-streptolysin O with positive throat culture of Group A streptococci. Four weeks after onset of the disease, serum complement level returned to normal, but proteinuria increased into the nephrotic range with a deterioration in renal function. Four weeks after onset, light microscopy of a renal biopsy showed diffuse endocapillary proliferation, and immunofluoroscopy revealed predominant IgA deposition in the mesangium. Electron microscopy showed electron dense deposits in the mesangial and subendothelial area, but subepithelial deposits were not found in the glomeruli. Histological diagnosis was IgA nephropathy, while her clinico-serological features were typical of acute post-streptococcal glomerulonephritis. CONCLUSION: These results suggest that in some patients, IgA nephropathy may be triggered by streptococcal infection and misdiagnosed as acute post-streptococcal glomerulonephritis if renal histological examinations are not done.

Acute Disease↗
PubMed1996

Strangulation ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion.

We treated a patient with a mechanical ileus resulting from encasement of a loop of the small intestine by the great omentum, caused by abnormal adhesion. Apart from its occurrence postoperatively with laparotomy, strangulation of small intestine into the omentum is very rare, and its occurrence without underlying disease, except in children, has not been documented previously.

Aged↗
PubMed1996

Resuscitation of ischemically damaged pancreas by the two-layer (University of Wisconsin solution/perfluorochemical) mild hypothermic storage method.

We have shown that 24-hour preservation by a two-layer [University of Wisconsin solution (UW)/perfluorochemical (PFC)] cold storage method at 4 degrees C allowed tissue ATP synthesis and resuscitated canine pancreases subjected to 90 minutes of warm ischemia. The purpose of this study was to examine whether the two-layer (UW/PFC) mild hypothermic storage method at 20 degrees C could shorten a preservation period for recovery of ischemically damaged pancreas and clarify changes of tissue adenine nucleotide metabolism and tissue perfusions. After 90 minutes of warm ischemia, canine pancreas grafts were preserved by the two-layer method and then autotransplanted. Tissue adenine nucleotide levels at the end of preservation and tissue perfusions after reperfusion were measured. Pancreas grafts subjected to 90 minutes of warm ischemia did not survive (0 of 5), without preservation. During a 5-hour preservation by the two-layer cold storage method the grafts did not synthesize enough ATP to repair damaged cell, although tissue perfusions were maintained after reperfusion. Consequently, ischemically damaged pancreases were not resuscitated (0 of 3). However, during 5-hour preservation by the two-layer mild hypothermic storage method, the grafts supplied enough ATP for processes that repair damaged cells, and tissue perfusions were maintained after reperfusion. As a result, ischemically damaged grafts were resuscitated (5 of 5). We conclude that 5-hour preservation by the two-layer mild hypothermic storage method accelerates ATP synthesis, which is essential for repairing damaged cells and protects the vascular microcirculation. This method can resuscitate ischemically damaged pancreas faster and holds promise for pancreas-kidney transplantation from cardiac arrest donors.

Adenine Nucleotides↗
PubMed1996

Occurrence of Borrelia garinii oculo-neuroborreliosis in Japan.

We report a 64-year-old Japanese man with oculo-neuroborreliosis. His clinical features consisted of polyarthralgia, keratoconjunctivitis, chorioretinitis, optic neuritis, confusion, and polyradiculitis. Assay of antibodies to Borrelia species detected IgG-antibody to B. garinii in both serum and CSF. Progressive declining of serum IgG antibody titer against Borrelia garinii, in parallel with clinical improvement, was observed after administration of ceftriaxone.

Aged↗
PubMed1996

Expression of c-fos mRNA after audiogenic seizure in adult rats with neonatal hypothyroidism.

In situ hybridization histochemistry was used to evaluate the expression of the immediate-early gene c-fos following the induction of audiogenic seizures in adult rats with transient neonatal hypothyroidism. The rats treated with 0.02% propylthiouracil (PTU) through mother's milk during days 0-19 after delivery showed a high incidence of seizures to auditory stimulation at the age of 4 months. The significant induction of c-fos mRNA by audiogenic seizures is prominent in several brain areas including central gray, peripeduncular nucleus, inferior colliculus, septal nucleus, bed nucleus of stria terminalis, and dorsomedial hypothalamus. However, the expression of c-fos mRNA was comparable in neocortex, dorsal hippocampus and medial geniculate body between control rats and PTU-treated, seizure-induced rats. These results confirm the previous report on the c-fos expression following audiogenic seizure sensitized during development by a loud noise [20]. The present results indicate that the neonatal PTU treatment may provide a useful tool for studying the mechanism underlying the seizure susceptibility and development after maturation.

Acoustic Stimulation↗
PubMed1996

Successful 14-day preservation of rat skin using a two-layer cold-storage method.

Skin-graft preservation for the purpose of delayed autografting to burn patients is a basic tool of plastic and burn surgery. This study was undertaken to evaluate the efficacy of the two-layer (physiological saline/perfluorochemical (PFC)) cold-storage method for skin preservation. In Wistar rats, a full-thickness skin graft, 3 cm in diameter, was harvested from the back, and separated from the dermis to obtain the epidermal sheet. This epidermal sheet was preserved at 4 degrees C using physiological saline (group 1, n = 15), physiological saline bubbled with a 95 per cent oxygen, 5 per cent carbon dioxide mixture (group 2, n = 15) or a two-layer method with bubbling with 95 per cent oxygen and 5 per cent carbon dioxide mixture (group 3, n = 15). The epidermal skin sheets were then autotransplanted to the backs of the original donor rats 7, 10 and 14 days after the start of preservation. The success rate of the skin autotransplantation was determined by measuring the ratio of viable area to total graft area 7 days after grafting. In group I, the success rates after 7, 10 and 14 days' perservation were 56.4, 47.4 and 0.09 per cent, respectively. In group 2, the corresponding success rates were 62.0, 48.4 and 0.8 per cent respectively, showing no improvement with oxygenated saline. In clear contrast, the success rates were significantly improved by the two-layer method, the values being 92.1, 87.9 and 77.6 per cent after 7, 10 and 14 days of perservation, respectively (P < 0.01 vs. groups 1 and 2 for all preservation durations). Based on these results, we concluded that the two-layer method is useful for not only improving the quality of the skin graft but also extending the preservation time of the skin graft up to 14 days.

Animals↗
PubMed1996

Locations of local anesthetic dibucaine in model membranes and the interaction between dibucaine and a Na+ channel inactivation gate peptide as studied by 2H- and 1H-NMR spectroscopies.

To study the molecular mechanisms of local anesthesia, locations of local anesthetic dibucaine in model membranes and the interactions of dibucaine with a Na+ channel inactivation gate peptide have been studied by 2H- and 1H-NMR spectroscopies. The 2H-NMR spectra of dibucaine-d9 and dibucaine-d1, which are deuterated at the butoxy group and at the 3 position in its quinoline ring, respectively, have been observed in multilamellar dispersions of the lipid mixture composed of phosphatidylcholine, phosphatidylserine, and phosphatidylethanolamine. 2H-NMR spectra of deuterated palmitic acids incorporated, as a probe, into the lipid mixture containing cholesterol have also been observed. An order parameter, SCD, for each carbon segment was calculated from the observed quadrupole splittings. Combining these results, we concluded that first, the butoxy group of dibucaine is penetrating between the acyl chains of lipids in the model membranes, and second, the quinoline ring of dibucaine is located at the polar region of lipids but not at the hydrophobic acyl chain moiety. These results mean that dibucaine is situated in a favorable position that permits it to interact with a cluster of hydrophobic amino acids (Ile-Phe-Met) within the intracellular linker between domains III and IV of Na+ channel protein, which functions as an inactivation gate. To confirm whether the dibucaine molecule at the surface region of lipids can really interact with the hydrophobic amino acids, we synthesized a model peptide that includes the hydrophobic amino acids (Ac-GGQDIFMTEEQK-OH, MP-1), the amino acid sequence of which corresponds to the linker part of rat brain type IIA Na+ channel, and the one in which Phe has been substituted by Gln (MP-2), and measured 1H-NMR spectra in both phosphate buffer and phosphatidylserine liposomes. It was found that the quinoline ring of dibucaine can interact with the aromatic ring of Phe by stacking of the rings; moreover, the interaction can be reinforced by the presence of lipids. In conclusion, we wish to propose that local anesthesia originates from the pi-stacking interaction between aromatic rings of an anesthetic molecule located at the polar headgroup region of the so-called boundary lipids and of the Phe in the intracellular linker between domains III and IV of the Na+ channel protein, prolonging the inactivated state and consequently making it impossible to proceed to the resting state.

Amino Acid Sequence↗
PubMed1996

Usefulness of QRST isointegral maps for the diagnosis of right ventricular pressure overload in patients with surgically repaired tetralogy of Fallot complicated by right bundle block.

Right ventricular pressure overload was evaluated in 29 patients, 8-12 years old, with surgically repaired tetralogy of Fallot by using body surface QRST isointegral maps. In patients with right ventricular systolic pressure above 50 mmHg, the maxima of the isointegral maps tended to shift toward the lower right-hand region of the map. The maximum value was significantly correlated with right ventricular systolic pressure (r = .58; P < .01). There was a correlation between the right ventricular systolic pressure and the percentage +2SD and percentage +5SD departure areas, which are defined as the area (expressed as a percentage of the total chest area) in which the QRST integral values are greater than the normal mean +2SD or +5SD, respectively (r = .61 and .84, P < .01). The QRST isointegral map can be used to evaluate right ventricular pressure overload in postoperative patients with tetralogy of Fallot complicated by right bundle branch block. The percentage +5SD departure area is the most valuable parameter for the quantitative evaluation of the right ventricular systolic pressure.

Body Surface Potential Mapping↗
PubMed1996

High helicity of peptide fragments corresponding to beta-strand regions of beta-lactoglobulin observed by 2D-NMR spectroscopy.

BACKGROUND: Whereas protein fragments, when they are structured, adopt conformations similar to that found in the native state, the high helical propensity of beta-lactoglobulin, a predominantly beta-sheet protein, suggested that the fragments of beta-lactoglobulin can assume the non-native helical conformation. In order to assess this possibility, we synthesized four 17-18-residue peptides corresponding to three beta-strand regions and one helical region (as a control) of beta-lactoglobulin and examined their conformation. RESULTS: We observed residual helicities of up to 17% in water, by far-UV CD, for all four peptide fragments. The helices could be significantly stabilized by the addition of TFE, and the NMR analyses in a mixture of 50% water/TFE indicated that helical structures are formed in the central region whereas both termini are frayed. Thus, the very same residues that form strands in the native beta-lactoglobulin showed high helical preferences. CONCLUSIONS: These results stand out from the current general view that peptide fragments isolated from proteins either are unfolded or adopt native-like secondary structures. The implications of the results in the mechanism of protein folding and in designing proteins and peptides are significant.

Amino Acid Sequence↗
PubMed1996

Chronic stress impairs rat spatial memory on the Y maze, and this effect is blocked by tianeptine pretreatment.

Chronic restraint stress causes significant dendritic atrophy of CA3 pyramidal neurons that reverts to baseline within a week. Therefore, the authors assessed the functional consequences of this atrophy quickly (within hours) using the Y maze. Experiments 1-3 demonstrated that rats relied on extrinsic, spatial cues located outside of the Y maze to determine arm location and that rats with hippocampal damage (through kainic acid, colchicine, or trimethyltin) had spatial memory impairments. After the Y maze was validated as a hippocampally relevant spatial task, Experiment 4 showed that chronic restraint stress impaired spatial memory performance on the Y maze when rats were tested the day after the last stress session and that tianeptine prevented the stress-induced spatial memory impairment. These data are consistent with the previously demonstrated ability of tianeptine to prevent chronic stress-induced atrophy of the CA3 dendrites.

Animals↗
PubMed1996

Glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) genetic polymorphism and susceptibility to gastric and colorectal adenocarcinoma.

Genes coding for the glutathione S-transferase M1 (GSTM1) and Theta 1 (GSTT1) proteins are polymorphic in humans and these genes are absent, or homozygous null, in 10-60% of different ethnic populations. These enzymes catalyze the conjugation of glutathione to numerous carcinogenic chemicals and previous epidemiologic studies have associated the null genotypes of these GST genes with higher risk of cancer. In this study the frequency of GSTM1 and GSTT1 null genotypes was determined in Japanese patients with gastric adenocarcinoma and colorectal adenocarcinoma and compared to frequencies determined in a community-based control group. The frequency of the null GSTM1 genotype in patients with gastric adenocarcinoma (56.8%) showed a statistically significant increase compared to the control group frequency (43.6%) (odds ratio (OR) = 1.70; 95% CI, 1.05-2.76). The frequency of GSTM1 null individuals was also higher among all colorectal adenocarcinoma cases, but this increase did not reach statistical significance. After grouping by tumor site, the GSTM1 null genotype was a risk factor among the subgroup with distal colorectal tumors (61.1%) (OR = 2.03; 95% CI, 1.06-3.90). No consistent difference was observed between smoking patients and corresponding controls for the frequency of the GSTM1 null genotype for either cancer, although a large risk (OR = 5.76; 95% CI 1.18-28.3) was associated with the GSTM1 null genotype in the low smoking group of gastric adenocarcinoma patients. On the other hand, no statistically significant differences were observed in the frequency of null GSTT1 genotypes in gastric (47.5%) or colorectal (48.5%) adenocarcinoma patients when compared with the control population (44.4%). These results suggest that the GSTM1 null genotype may be associated with susceptibility to gastric adenocarcinoma and distal colorectal adenocarcinoma in Japanese; however, the associations observed were relatively weak and additional studies will be needed to confirm these findings.

Adenocarcinoma↗
PubMed1996

Endothelium-dependent relaxation of rat thoracic aorta by amrinone-induced nitric oxide release.

To determine whether amrinone and its induced increase of cyclic AMP releases nitric oxide and enhances endothelium-dependent vascular relaxation, we studied nitric oxide production and vascular relaxation of rat thoracic aorta on treatment with amrinone and forskolin, an activator of adenylate cyclase. When 20 microM amrinone was applied to ring segments of aorta previously contracted with phenylephrine, relaxation was greater in segments with endothelium than in those without (% relaxation 94 +/- 4 vs 37 +/- 7%, P < 0.01). However, a higher concentration of amrinone (> 50 microM) induced the same degree of relaxation in ring segments with or without endothelium, probably due to its direct effect on vascular smooth muscle. The maximal relaxant concentration (100 microM) of amrinone induced an increase (2.5 fold) in cyclic GMP in ring segments. Forskolin also induced concentration-dependent relaxation, but removal of the endothelium attenuated the relaxation induced by forskolin about seven-fold. NG-nitro L-arginine reversed the relaxation induced by amrinone or forskolin in ring segments with, but not without, endothelium. Nitric oxide production in ring segments of aorta, following application of amrinone or forskolin, was detected by nitric oxide-selective electrode and electron paramagnetic resonance spin trapping methods. Pre-treatment with NG-nitro L-arginine or removal of the endothelium suppressed nitric oxide production by amrinone or forskolin. These data showed that amrinone enhances the release of nitric oxide from rat aortic endothelial cells, and induces endothelium-derived relaxing factor/nitric oxide-mediated vasodilation.

Amrinone↗
PubMed1996

Preservation of the ration of cerebral blood flow/metabolic rate for oxygen during prolonged anesthesia with isoflurane, sevoflurane, and halothane in humans.

BACKGROUND: In several animal studies, an increase in cerebral blood flow (CBF) produced by volatile anesthetics has been reported to resolve over time during prolonged anesthesia. It is important to investigate whether this time-dependent change of CBF takes place in humans, especially in clinical situations where surgery is ongoing under anesthesia. In this study, to evaluate the effect of prolonged exposure to volatile anesthetics (isoflurane, sevoflurane, and halothane), the CBF equivalent (CBF divided by cerebral metabolic rate for oxygen (CMRO2) was determined every 20 min during anesthesia lasting more than 4h in patients. METHODS: Twenty-four surgical patients were assigned to three groups at random to receive isoflurane, sevoflurane, or halothane (8 patients each). End-tidal concentration of the selected volatile anesthetic was maintained at 0.5 and 1.0 MAC before surgery and then 1.5 MAC for the 3 h of surgical procedure. Normothermia and normocapnia were maintained. Mean arterial blood pressure was kept above 60 mmHg, using phenylephrine infusion, if necessary. CBF equivalent was calculated every 20 min as the reciprocal of arterial-jugular venous oxygen content difference. RESULTS: CBF equivalent at 0.5 MAC of isoflurane, halothane, and sevoflurane was 21 +/- 4, 20 +/- 3, and 21 +/- 5 ml blood/ml oxygen, respectively. All three examined volatile anesthetics significantly (P<0.01) increased CBF equivalent in a dose-dependent manner (0.5, 1.0, 1.5 MAC). AT 1.5 MAC, the increase of CBF equivalent with all anesthetics was maintained increased with minimal fluctuation for 3 h. The mean value of CBF equivalent at 1.5 MAC in the isoflurane group (45 +/- 8) was significantly (P<0.01) greater than those in the halothane (32 +/- 8) and sevoflurane (31 +/- 8) groups. Electroencephalogram was found to be relatively unchanged during observation periods at 1.5 MAC. CONCLUSIONS: These results demonstrate that CBF/CMRO2 ratio is markedly increased above normal and maintained during prolonged inhalation of volatile anesthetics in humans. It is impossible to determine whether these data indicate a stable CBF or whether CBF and CMRO2 are changing in parallel during the observation period. The unchanging electroencephalographic pattern suggests that the former possibility is more likely and that the increase of CBF produced by volatile anesthetics is maintained over time without decay, which has been reported in several animal studies. It also is suggested that isoflurane possesses greater capability to maintain global CBF relative to CMRO(2) than does halothane or sevoflurane. time.)

Adult↗
PubMed1996

Possible role for a polysaccharide antigen shared between Streptococcus pyogenes and S. mutans in the pathogenesis of poststreptococcal glomerulonephritis.

Streptococcus mutans has been shown to share a polysaccharide (PS) antigen with S. pyogenes strains isolated from patients with acute poststreptococcal glomerulonephritis (PSGN), using a monoclonal antibody f-77 reactive with the PS. To investigate the pathogenetic role of the shared PS in PSNG, experimental nephritis was induced in animals. Rats were immunized thrice with heat-killed cells of S. mutans or S. pyogenes, followed by an intravenous injection of live cells of S. pyogenes. Histologic examination showed that both animal groups had comparable degrees of diffuse proliferative nephritis characterized by immune deposits. The shared PS antigen was detected in glomeruli of all nephritic rats by immunofluorescence using monoclonal antibody f-77. Furthermore, all nephritic rats had an elevated antibody titer to the shared PS antigen. These results suggest that prior sensitization (infections such as dental caries) to S. mutans modulates immune responses to subsequent S. pyogenes infections and induces immune-complex disease (PSGN) through the shared PS antigen.

Acute Disease↗
PubMed1996

Recovery of adenosine triphosphate tissue levels of grafts preserved by the two-layer method after reperfusion.

Recovery of tissue adenosine triphosphate (ATP) levels after transplantation is very important for graft survival. We examined whether the pancreas grafts preserved by the two-layer method have the ability to synthesize ATP after reperfusion, and this is one of the mechanisms of action for the two-layer method in successful pancreas preservation. After preservation by the two-layer method using Euro-Collins' solution (EC) for 48 h (Group 1, n = 5) or simple cold storage in EC for 48 h (Group 2, n = 5), canine pancreas grafts were autotransplanted. In controls (Group 3, n = 5), canine pancreas grafts were autotransplanted without preservation. Graft viability was judged from graft survival after transplantation. Tissue adenine nucleotide concentrations were measured using high performance liquid chromatography after preservation, before reperfusion, and after 1 and 2 h of reperfusion. Graft survival rates were 5 of 5, 0 of 5, and 5 of 5, in Groups 1, 2, and 3, respectively. However ATP tissue levels in Group 1 were significantly higher compared with those in Group 2 after preservation and before reperfusion, respectively (10.95 +/- 1.52 vs. 2.75 +/- 0.33 and 2.90 +/- 0.51 vs. 2.03 +/- 0.68 mumol/g dry weight, p < 0.01 and p < 0.05, respectively). Total tissue adenine nucleotide levels in Group 1 before reperfusion were 7.41 +/- 1.47 mumol/g dry weight, and there was no significant difference compared with Group 2, 6.64 +/- 2.23 mumol/g dry weight. After reperfusion, there was no significant difference of ATP tissue levels between Groups 1 and 2 (4.07 +/- 1.18 vs. 4.48 +/- 1.32, not significant [NS]) after 1 h of reperfusion. However, after 2 h of reperfusion, tissue ATP levels in Group 1 (6.71 +/- 1.19 mumol/g dry weight) were significantly higher than were those in Group 2 (4.51 +/- 0.51 mumol/g dry weight, p < 0.01) and almost at the same levels as control (6.32 +/- 1.62 mumol/g dry weight). It was clear that recovery of ATP after reperfusion did not depend on the residual nucleotides pool but on the ability of the pancreas graft to synthesize ATP after reperfusion. We conclude that oxygenation of the pancreas graft during preservation by the two-layer method allows for ATP synthesis, which is essential in maintaining cellular integrity and leads to maintaining the graft's ability to synthesize ATP promptly after reperfusion. This is one of the mechanisms of action of the two-layer method in successful pancreas preservation.

Adenosine Triphosphate↗