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Biomedical subjects

Y Hamada

Publications and source records attributed to Y Hamada.

At least 271 records · Page 15Linked to original sources
PubMed1996

[Two cases of Candida endocarditis associated with abdominal disease].

Two cases of Candida endocarditis are reported. The first case was of a 63-year-old man who had a positive blood culture for Candida albicans during treatment for liver abscess and early gastric cancer. He was transferred to our department, and aortic and tricuspid regurgitation due to Candida endocarditis was diagnosed. The patient was successfully treated with aortic valve replacement, tricuspid valve plasty and anti-fungal agents. The second case was of a 65-year-old man who complained of fever. Despite a diagnosis of common bile duct cancer and resection of the tumor, the fever persisted. He was transferred to our department and was diagnosed having aortic regurgitation due to Candida endocarditis, complicated by heart failure. Although intense medical therapy including antifungal agents, diuretics, catecholamines and digoxin was initiated, the patient died from multiple embolisms 9 days later. In the treatment of Candida endocarditis, early diagnosis and early decision-making for either surgical or medical therapy is indispensable. Although the prevalence of Candida endocarditis is low, the differentiation of this disease should be taken into account in febrile elderly patients with long-standing therapy with antibiotics.

Aged↗
PubMed1996

Effect of propionyl-L-carnitine on motor nerve conduction, autonomic cardiac function, and nerve blood flow in rats with streptozotocin-induced diabetes: comparison with an aldose reductase inhibitor.

The effects of propionyl-L-carnitine (PCAL) on caudal motor nerve conduction velocity, the coefficient of variation of the R-R interval on the electrocardiogram, and sciatic nerve blood flow were compared with those of [5-(3-thienyl)tetrazol-1-yl] acetic acid monohydrate, an aldose reductase inhibitor, in rats with streptozotocin-induced diabetes. Diabetic control rats showed significantly delayed nerve conduction (P < .05), decreased R-R variability (P < .05) and reduced sciatic nerve blood flow (P < .05). Oral administration of PCAL (0.5 g/kg/day) and [5-(3-thienyl)tetrazol-1-yl] acetic acid monohydrate (0.05% in the diet: 60 mg/kg/day) for 8 weeks significantly improved both nerve conduction (P < .05) and R-R variability (P < .05) in diabetic rats, along with the normalization of sciatic nerve blood flow. PCAL treatment increased the nerve tissue levels of carnitine and myo-inositol and reduced the serum triglyceride level in diabetic rats. Our results suggests that PCAL could have therapeutic potential for the treatment of diabetic neuropathy.

Aldehyde Reductase↗
PubMed1996

[Ten-year survival and cardiac event-free rates in Japanese patients with the left anterior descending artery revascularized with internal thoracic artery or saphenous vein graft: a comparative study].

To evaluate the long-term results of surgical patients with coronary artery bypass grafting (CABG), we comparatively analyzed the 10-year survival and cardiac event-free rates between 713 patients group with at least one internal thoracic artery to the left anterior descending artery (LAD), (ITA-CABG) and 241 patients group revascularized with vein grafts alone (SVG-CABG). ITA-CABG patients had more progressed diseases with a higher incidence of risk factors than SVG-CABG patients: number of vessel diseased 2.5 +/- 0.7 vs 2.3 +/- 0.7, LMTD 20.2% vs 14.1%, diabetes mellitus 37.3% vs 27.0% and hyperlipidemia 38.0% vs 30.7%. The 10-year cumulative LAD graft patency and severe disease-free rate was 90.3 and 67.0% for ITAs and vein grafts in this series. The 10-year overall actuarial survival, cardiac death-free and cardiac event-free rates for ITA and SVG groups were 88.8 vs 79.5%, 97.4 vs 92.6% and 84.1 vs 73.1%, all with a statistical significance (generalized Wilcoxon or logrank method). For the patients with reduced ventricular systolic function (EF < or = 0.4), ITA-CABG offered a significantly better 10-year cardiac death free rate. Also, for the diabetic patients, ITA-LAD offered a significantly better 10-year cardiac event-free rate. In conclusion, the use of ITA graft can reduce postoperative cardiac events and enhance the long-term survival in Japanese patients. The ITA should be utilized at least for LAD in all CABG patients whenever feasible.

Coronary Artery Bypass↗
PubMed1996

[A case of carcinomatous peritonitis for which combination therapy of 5-FU, leucovorin and cisplatin was effective].

This case report describes a case of carcinomatous peritonitis which showed a good response to the combination therapy of 5-FU, leucovorin and cisplatin. A 55-year-old man was admitted with complaints of meteorism due to ascites fluid. Ascitic examination showed a high concentration of CEA and CA19-9, and adenocarcinoma cells. Laboratory and radiological examination did not reveal the origin of the carcinoma, and laparotomy suggested an appendiceal origin. The combination chemotherapy with 5-FU, leucovorin and cisplatin was conducted for a total of 11 courses for 2 years with good QOL until his death. This therapy was suggested to be useful for inoperable carcinomatous peritonitis.

Adenocarcinoma↗
PubMed1996

[Primary transitional cell carcinoma of the prostatic urethra: a case report].

A case of primary transitional cell carcinoma of the prostatic urethra is reported. A 60 year-old male, with a chief complaint of difficult urination consulted our clinic on March, 1994. Urethrography and endoscopic examination revealed the solitary tumor of the prostatic urethra and transurethral resection was performed. Histologically, the tumor was Grade 2 transitional cell carcinoma without submucosal invasion. The post-operative course was uneventful and no recurrence has been seen. To our knowledge, including our case, 10 cases of primary transitional cell carcinoma of the prostatic urethra have been reported in the Japanese literature.

Carcinoma, Transitional Cell↗
PubMed1996

[Studies on cerebrospinal fluid penetration of cefpirome in adult with meningitis].

A patient with intracerebral hematoma suffered from postoperative bacterial meningitis. Staphylococcus aureus was found from CSF. The organism was multiple drug resistant and refractory to antibiotics including piperacillin (PIPC), cephalexin (CEX), cefotaxime (CTX), ceftazidime (CAZ) and latamoxef (LMOX). It was susceptible to cefpirome (CPR). Treatment with CPR resulted in clinical improvement associated with clearing of the organism from CSF. Serum level of CPR was high enough and CPR penetration into the CSF was satisfactory. The results suggest that CPR is an extremely effective antibiotic for meningitis caused by CPR-susceptible bacteria. Evaluation of the CPR penetration into the CSF of adult meningitis was rarely reported. The result we obtained was important in the treatment for the adult meningitis.

Adult↗
PubMed1996

[Parasagittal meningioma growing in the superior sagittal sinus presenting intracranial hypertension: a case report].

Parasagittal meningiomas often invade the superior sagittal sinus (SSS), but rarely grow inside the SSS as a primary tumor. The authors report a case of parasagittal meningioma growing mainly inside the SSS and presenting papilledema. The SSS is invisible behind the tumor end on the right carotid angiogram but still patent on the left carotid angiogram. The superficial cortical vein on the opposite side works as a collateral pathway. The tumor may have originated from the right wall of the SSS, grew inside the sinus and covered the entrances of the right ascending cerebral veins. V-P shunt was performed after removal of the mass outside the sinus for resolving headache and visual symptoms.

Brain Neoplasms↗
PubMed1996

Isolation of a novel chick homolog of Serrate and its coexpression with C-Notch-1 in chick development.

Intercellular signaling mediated by the transmembrane proteins, Notch as receptor and its ligands, Delta and Serrate, plays essential roles in the developmental fate decision of many cell types in Drosophila. The Notch genes are highly conserved both in invertebrates and in vertebrates, suggesting that Notch pathway regulates cell fate decisions during vertebrates development. Notch, Delta and Serrate homologs in chicken have been cloned (Henrique et al., Nature 375: 787-790, 1995; Myat et al., Dev. Biol. 174: 233-247, 1996). We isolated a novel chick homolog of Drosophila Serrate, named C-Serrate-2, and examined its expression patterns during the early chick development using whole-mount in situ hybridization. C-Serrate-2 transcripts were detected in several tissues including the forebrain, the myotome and the apical ectodermal ridge (AER) of the limb bud of a 4-day-old chick embryo. In most of the regions where C-Serrate-2 was expressed, C-Notch-1 was also expressed. Our observations suggest that Serrate-2-Notch-1 signaling plays a role in a variety of morphogeneses during the chick development.

Amino Acid Sequence↗
PubMed1995

Polyol pathway, 2,3-diphosphoglycerate in erythrocytes and diabetic neuropathy in rats.

The relationship between the 2,3-diphosphoglycerate concentration in red blood cells as a biological indicator of tissue hypoxia and diabetic neuropathy, and the effect of a potent aldose reductase inhibitor, (2S,4S)-6-fluoro-2'5'-dioxospiro [chroman-4,4'-imidazolidine]-2-carboxamide (SNK-860), on both were investigated in streptozotocin-induced diabetic rats. Diabetic rats demonstrated significantly delayed motor nerve conduction velocity and reduced sciatic nerve blood flow. Altered biochemical features in the sciatic nerves, including a marked accumulation of sorbitol and fructose, myo-inositol depletion and decreased Na+/K(+)-ATPase activity were also detected in diabetic rats. These defects were accompanied by a decrease in the red blood cell 2,3-diphosphoglycerate concentration. Treatment with SNK-860 partially or completely ameliorated these abnormalities. These observations suggest that a decrease in the red blood cell 2,3-diphosphoglycerate concentration is one of the factors contributing to tissue hypoxia, which results in diabetic neuropathy, and that this decrease is mediated through an aldose reductase inhibitor-sensitive pathway.

2,3-Diphosphoglycerate↗
PubMed1995

Na-dependent glutamate transport in high K and high glutathione (HK/HG) and high K and low glutathione (HK/LG) dog red blood cells.

Na-dependent glutamate (Glu) influxes in the red blood cells of normal low K (LK), high K and high glutathione (HK/HG), and high K and low glutathione (HK/LG) dogs were compared. The ranges of the influxes in LK, HK/HG and HK/LG cells were 1.0-63, 62-174 and 1.3-26 mumol/1 cells per h, respectively. Some LK and HK/LG dogs had red blood cells with extremely low Glu influxes. In cells with extremely low Glu influxes, however, there were clear Na-dependent Glu influxes. In LK, HK/HG and HK/LG cells, the Km of Na-dependent Glu influx with respect to the medium Glu concentration were 17, 20 and 19 mM, respectively, and the half-maximal activation (K1/2) with respect to medium Na concentration was 39, 40 and 42 microM, respectively. By the addition of harmaline, a hallucinogenic alkaloid, the Vmax in LK cells was not affected and the Km was increased, while the Vmax was decreased and the Km increased in HK/HG and HK/LG cells. The Ki value with harmaline by means of Dixon plot in LK cells was 5.2 mM, against 1.8 and 1.9 mM in HK/HG and HK/LG cells, respectively. These results suggest that the difference in the Na-dependent Glu influxes between 2 HK groups was due to the varying quantity, not the quality, of the transporter.

ATP-Binding Cassette Transporters↗
PubMed1995

Antigen-driven differentiation of naive Ig-transgenic B cells in vitro.

We have established a culture system in which naive B cells bearing a transgenic, chicken OVA (cOVA)-specific Ig differentiate to plasma cells in vitro after interaction with cOVA plus cOVA-specific helper T cells. B cell-enriched populations from Ig-transgenic mice, but not from nontransgenic mice, proliferated after presenting nanomolar concentrations of cross-linked cOVA to DO11.10 (cOVA plus IAd-specific) T cells. After 6 to 9 days of culture with Ag and specific T cells, the B cells acquired a plasma cell phenotype and secreted the transgene-derived Ig at high levels. Engagement of B cell surface Ig was not essential for primary B cell differentiation. Differentiating B cells enlarged, clustered, and acquired two plasma cell markers, Syndecan and CD43. B cell CD45 isoform expression changed: the B220 isoform was lost in a T cell-dependent manner, whereas the CD45RB isoform was gained in a T-independent manner. Although unstimulated B cells survived less than 72 h in vitro, those in Ag-stimulated cultures showed reduced early death, a surge of proliferation at 3 to 5 days, and increased death late in the culture. Using a large population of naive B cells of defined antigenic specificity permits us to study a primary immune response to an Ag, rather than to less physiologic polyclonal stimuli. Because all steps of differentiation occurred in vitro, they are easily accessible for study. This coculture system provides an opportunity to observe Ag-specific T cell-B cell collaboration.

Animals↗
PubMed1995

A new mitochondrial DNA mutation associated with non-insulin-dependent diabetes mellitus.

Mitochondria play an important role in glucose-induced insulin secretion in pancreatic beta cells. We therefore examined whether patients with NIDDM exhibit genetic variability in mitochondrial DNA (mtDNA), a candidate gene for NIDDM. We sequenced mtDNA in the region encoding tRNALeu and the adjacent region in several diabetic patients with clinical features suggesting mitochondrial DNA mutations. We found a new point mutation at position 3316 that leads to an amino acid change in the ND-1 protein. The frequency of the mutation was screened with PCR-RFLP in 295 NIDDM patients and 406 controls. We found ten NIDDM patients (3.4%) harbored the mutation. Although 4 control subjects had the mutation, the frequency was significantly higher in the NIDDM patients than in the control subjects (p = 0.02). These results suggest that the 3316 mutation is associated with NIDDM.

Base Sequence↗
PubMed1995

Absorption of new HIV-1 protease inhibitor, KNI-272, after intraduodenal and intragastric administrations to rats: effect of solvent.

KNI-272 is a tripeptide drug that has a strong pharmacological potential for treating human immunodeficiency virus type 1 (HIV-1). We have already reported the pharmacokinetic characteristics of KNI-272 after intravenous and intraduodenal (ID) administrations to rats. In this study, KNI-272 was administered to rats as a solution and the effect of four kinds of solvent on the bioavailability (BA) of KNI-272 was determined using rats. The mixtures included propylene glycol (PG) and water (70% PG), a solution of PG (100% PG), a solution of Tween 80 (Tween 80), and a mixture of PG and HCO60, a polyoxyethylated, 60 mumol, castor oil derivative (PG:HCO60 = 7:3). After ID administration to rats at a dose of 50.0 mg kg-1, the mean peak plasma concentrations, Cmax, were 2.58 +/- 0.53 (SE) (70% PG), 3.28 +/- 0.51 (100% PG), 3.15 +/- 0.51 (Tween 80), and 4.66 +/- 0.68 micrograms mL-1 (PG:HCO60). The highest BA, 44.6%, was obtained after ID administration of KNI-272 dissolved in PG:HCO60. On the other hand, after intragastric (IG) administration of KNI-272 solution in which the drug was dissolved with PG:HCO60, the Tmax, the Cmax, and the BA were 1.25 +/- 0.60 h, 2.33 +/- 0.65 micrograms mL-1, and 24.2%, respectively. The Cmax and BA values were equal to half of the values obtained after ID administration of KNI-272 dissolved in the same solution. In this study, as the PG concentration in the solution increased and the other additives (Tween 80 and HCO60) were coadministered, the BA of KNI-272 after ID administration increased. These results suggest that, for the development of an oral dosage form of KNI-272, a non-ionic surfactant that dissolves in the duodenum or small intestine and that enhances the absorption of this drug from the gastrointestinal tract into the enterocytes is needed.

Administration, Oral↗
PubMed1995

Conformational analysis of dolastatin 10: an NMR and theoretical approach.

A solution conformational analysis of dolastatin 10, a powerful antineoplastic agent, has been carried out by means of nmr techniques and theoretical calculations. 1H mono- and bidimensional nmr experiments, as well as 1H-13C heterocorrelated spectra, have been performed on CD2Cl2 solutions. The most interesting nmr data is a huge shielding of the aCH(25) proton of the Dov residue, suggesting the presence of an interaction between the N-terminal and the aromatic C-terminal ends of the molecule. The possibility of a head-to-tail intermolecular association having been discarded, the presence of a series of preferred folded conformation has been hypothesized. Conformational theoretical analysis supports the nmr hypothesis of a folded peptide-like molecule, and a series of possible conformers in good agreement with the experimental data have been analyzed.

Amino Acid Sequence↗
PubMed1995

Effects of hydroxyapatite and alumina sheaths on postoperative peritendinous adhesions in chickens.

Two experimental methods for restoring flexor tendon sheath integrity and preventing adhesions around traumatized flexor tendons utilizing artificial tendon sheaths made of either hydroxyapatite (HAp) or alumina were studied in a flexor tendon-trauma model and compared to a standard tendon sheath repair and a control. Eighty toes were divided equally into a control group, a sheath repair group, an HAp group, and an alumina group. Profundus tendons in zone II were divided and repaired after sublimis excision in all groups. In the sheath repair group, the flexor sheath was also repaired after suturing the tendon. In artificial sheath groups, sheaths made of HAp and alumina were placed over the repair sites to protect them from the surrounding tissues. In the control group, after repairing the tendon, the flexor sheath was excised and no artificial sheaths were used. Each toe was immobilized in a plaster cast for 3 weeks. After three weeks, the plaster cast was removed followed by the removal of the sheaths in the artificial sheath groups through a small incision in the skin in zone II. Active mobilization was encouraged in each group. Postoperative adhesions were examined at 3, 6, 9, and 12 week intervals by using light microscopic techniques. To further explore the effects of artificial sheaths on tendon healing, transmission electron microscopy was done for the HAp and alumina groups at 3, 6, and 12 week intervals. Results demonstrated decreased severity of postoperative adhesions in the HAp as well as in the alumina groups in comparison with the sheath repair and controls. A space resembling the fibro-osseous canal was formed around the tendon after removing the sheaths. This space remained patent until 12 weeks, 9 weeks after removing the sheaths, and a newly formed tendon sheath-like structure lined by synovial cells and with a peritenon-like structure over the tendon surface was observed. In the sheath repair and control groups, the severity of adhesions was decreased with the passage of time, to some extent due to unrestricted mobility. However, a newly formed tendon sheath or peritenon-like structure was not observed. Electron microscopic studies confirmed good healing at the suture in the HAp and alumina groups with no evidence of necrosis. These results are qualitative in nature as no statistical tests were performed. From these results we conclude that if the tendon is separated from the surrounding granulation tissue by a barrier with good biocompatibility, the tendon can heal with fewer adhesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Aluminum Oxide↗
PubMed1995

Surgical technique of laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis.

We report herein a new method of performing laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis, using refined surgical techniques. The pyloric tumor was immobilized by grasping the first portion of the duodenum and the anterior wall of the stomach, and electrocoagulation was used prior to incising the pyloric tumor to minimize bleeding during the procedure. Although this technique has been applied in only two patients so far, we present the details herein. We believe that with technical and instrumental refinements, the speed and safety of laparoscopic pyloromyotomy will improve and it will become an alternative to open surgery in pediatric patients.

Female↗
PubMed1995

A mutation in the glucagon receptor gene (Gly40Ser): heterogeneity in the association with diabetes mellitus.

A possible pathogenic mutation in the glucagon receptor gene causing a Gly to Ser change at codon 40 (Gly40Ser) was reported to be associated and linked with non-insulin-dependent diabetes mellitus (NIDDM), in France and Sardinia. Since the frequency of the mutation (Gly40Ser), about 5% in the French population of familial NIDDM and 8% in randomly chosen diabetic patients in Sardinia, was much higher than that of any of the previously reported mutations in candidate genes, it is important to clarify whether the contribution of this mutation to NIDDM is universal. In this study, we investigated the association of this mutation with diabetes mellitus in a large number of Japanese diabetic patients (383 NIDDM and 53 insulin-dependent diabetic patients) by polymerase chain reaction-restriction fragment length polymorphism analysis. None of the Japanese diabetic patients showed Gly40Ser mutation and the association of this mutation with NIDDM was significantly different (p < 4.10(-5) vs French, p < 3.10(-6) vs Sardinian by Fisher's exact test). The results not only indicate that the mutation plays little, if any, role in susceptibility to diabetes in Japan, but also indicate the genetic heterogeneity in NIDDM and further emphasize the importance of studies on genetic susceptibility to NIDDM and other complex traits in different ethnic groups.

Adolescent↗