Search PubMed⌕ Search

Biomedical subjects

T Yamada

Publications and source records attributed to T Yamada.

At least 451 records · Page 25Linked to original sources
PubMed2000

Independent pathways leading to apoptotic cell death, oxidative burst and defense gene expression in response to elicitin in tobacco cell suspension culture.

We characterized pharmacologically the hypersensitive cell death of tobacco BY-2 cells that followed treatments with Escherichia coli preparations of INF1, the major secreted elicitin of the late blight pathogen Phytophthora infestans. INF1 elicitin treatments resulted in fragmentation and 180 bp laddering of tobacco DNA as early as 3 h post-treatment. INF1 elicitin also induced rapid accumulation of H2O2 typical of oxidative burst, and the expression of defense genes such as phenylalanine ammonia-lyase (PAL) gene at 1 h and 3 h after elicitin treatment, respectively. To investigate the involvement of the oxidative burst and/or the expression of defense genes in the signal transduction pathways leading to hypersensitive cell death, we analyzed the effect of several chemical inhibitors of signal transduction pathways on the various responses. The results indicated that (a) the cell death required serine proteases, Ca2+ and protein kinases, (b) the oxidative burst was involved in Ca2+ and protein kinase mediated pathways, but elicitin-induced AOS was neither necessary nor sufficient for cell death and PAL gene expression, and (c) the signaling pathway of PAL gene expression required protein kinases. These results suggest that the three signal transduction pathways leading to cell death, oxidative burst and expression of defense genes branch in the early stages that follow elicitin recognition by tobacco cells.

Algal Proteins↗
PubMed2000

Localization of a novel type trypsin-like serine protease, neurosin, in brain tissues of Alzheimer's disease and Parkinson's disease.

Neurosin, a novel type of trypsin-like serine protease, has been shown to be preferentially expressed in human brain by northern blotting. We examined neurosin immunolabeling in the brains of neurologically normal persons and patients with Alzheimer's disease (AD) and with Parkinson's disease. We also identified the expression of the mRNA for neurosin by in situ hybridization histochemistry and reverse transcription-polymerase chain reaction (RT-PCR). The neurosin antibody stained all of the nuclei of various cell types. In neurons, there was also staining of neuronal cytoplasm, nucleoli and their processes. In AD, staining of neurons with processes was rare in the damaged areas. Some senile plaques, extracellular tangles and Lewy bodies were also positive for neurosin. Expression of the mRNA for neurosin was seen in neurons in the gray matter, and in microglial cells in the white matter. In AD, the intensity of the signal for neurosin mRNA in the gray matter was decreased compared with normal control brains. The relative levels of neurosin mRNA in AD brains, measured by RT-PCR, were lower than those in controls. These results suggest that in human brain neurosin plays various physiological roles, and that in AD this molecule, like other serine proteases, may have a role in the degradation of such substances as beta-amyloid protein.

Aged↗
PubMed2000

Influenza virus-induced encephalopathy: clinicopathologic study of an autopsied case.

BACKGROUND: Rapid progressive encephalopathy with a high fever, consciousness loss and recurrent convulsions has been occasionally reported in children during influenza pandemics in Japan since 1995. We examined a 2-year old girl with hemorrhagic shock and encephalopathy syndrome associated with acute influenza A virus infection (A/Nagasaki/76/98; H3N2), to answer several questions for which no histologic or virologic data exist. METHODS: A clinicopathologic study using immunohistochemical staining and viral genome detection by reverse transcriptase polymerase chain reaction (RT-PCR) was performed with this autopsied case. RESULTS: The virus antigen was positive in CD8+ T lymphocytes from the lung and spleen. The virus infected a very limited part of the brain, especially Purkinje cells in the cerebellum and many neurons in the pons, without inducing an overt immunologic reaction from the host. The RT-PCR used for detecting the hemagglutinin gene demonstrated positive bands in all frozen tissues and cerebrospinal fluid taken at autopsy and not in samples obtained on admission. CONCLUSIONS: The pathologic change induced by the direct viral invasion cannot be responsible for all of the symptoms, especially for the rapid and severe clinical course of the disease within 24-48 h after the initial respiratory symptoms. Together with the rapid production of several inflammatory cytokines, the breakdown of the blood-brain barrier may induce severe brain edema and can be a major pathologic change for the disease. Any therapeutic strategy to control this multistep progression of the disease could be effective.

Antigens, Viral↗
PubMed2000

Subtypes of bladder mast cells in interstitial cystitis.

BACKGROUND: Because the types of mast cells present in the bladder of patients with interstitial cystitis (IC) have not been elucidated, we have used immunohistochemical techniques to determine which of the mast cell types is present in biopsy specimens. METHODS: For all patients diagnosed with IC (n = 10; female) their symptoms satisfied the criteria proposed by the National Institutes of Health criteria of IC and six patients suffering from bladder tumors were selected as control patients. Adjacent sections of paraffin-embedded tissues that had been fixed in Carnoy's solution were reacted with either antitryptase or antichymase antibodies. RESULTS: In detrusor and in mucosa, the number of tryptase-positive and chymase-negative mast cells (MC(T)) was 146+/-25 and 81+/-31 cells/mm2, respectively, and the number of tryptase-positive and chymase-positive mast cells (MC(TC)) was 124+/-50 and 54+/-20 cells/mm2, respectively. These numbers were significantly greater than those of the control group. A significant negative correlation (P<0.005; R = 0.943) was observed between the number of MC(TC) and the bladder capacity. The number of mast cells obtained by toluidine blue staining in detrusor and in mucosa was 95+/-68 and 71+/-39 cells/mm2, respectively, suggesting that staining with toluidine blue underestimated the number of mast cells. CONCLUSIONS: Mast cells were significantly increased in number in both the mucosa and detrusor of bladder specimens from IC patients compared with those from control. The MC(TC) may be the type of mast cell dominantly present in the bladder of IC patients. The MC(TC) in detrusor increased with the progression of contracted bladder.

Adult↗
PubMed2000

Bilateral testicular tumors in androgen insensitivity syndrome.

We report on a case of complete androgen insensitivity syndrome with bilateral testicular tumors and a point mutation in the androgen receptor gene. A bilateral gonadecotmy was performed and both of the resected tumors were histologically diagnosed as pure seminoma. Direct sequencing of amplified exons E-G of the androgen receptor gene from the resected tumor identified a CGA to CAA substitution in exon E, resulting in arginine to glutamine replacement at codon 752. To our knowledge, this is the first reported case of androgen insensitivity syndrome with bilateral testicular tumors.

Androgen-Insensitivity Syndrome↗
PubMed2000

Synchronous esophageal and renal cell carcinoma.

Multiple cancer associated with esophageal cancer is not uncommon; however, synchronous esophageal and renal cell carcinoma is very rare. Only three cases have been reported to date, and one of these patients was treated in our institution. We have since successfully treated another patient. Here, we report the two cases treated in our institution. In the first case, esophagectomy, nephrectomy, and reconstruction using a gastric tube were carried out in one stage. Post-operative renal function was temporarily impaired by the complications of anastomotic leakage and pyothorax but no hemodialysis was needed. In the second case, as the patient had undergone distal gastrectomy because of gastric cancer, we chose a two-stage operation, i.e. esophagectomy and nephrectomy as the first stage, followed by reconstruction using a colon substitute after 4 weeks, resulting in only slight renal dysfunction. Patients 1 and 2 are alive and well 7 years and 2 years after the operations respectively.

Aged↗
PubMed2000

Interstitial cystitis in Japan.

OBJECTIVE: To determine the prevalence of interstitial cystitis in Japan, and to analyse the diagnostic criteria and treatments most commonly used by Japanese urologists. Materials and methods Questionnaires were sent to 300 urologists at major hospitals, including medical university hospitals, throughout Japan, asking about the number of patients with interstitial cystitis, its epidemiology, diagnosis and therapy. RESULTS: The prevalence of interstitial cystitis was 1.2 per 100 000 patients and 4.5 per 100 000 female patients; the male/female ratio was 1 : 5.8. Most Japanese urologists used two or more diagnostic criteria; bladder biopsy was the most common diagnostic method. Dimethyl sulphoxide instillations and corticosteroids were the most frequently used therapies. CONCLUSION: The prevalence of interstitial cystitis in Japan is markedly lower than that reported in Europe and North America. The reasons for this difference were not only racial but also the lack of awareness among Japanese urologists and patients about interstitial cystitis.

Adult↗
PubMed2000

Vacuum assisted cardiopulmonary bypass in minimally invasive cardiac surgery: its feasibility and effects on hemolysis.

The present study describes a cardiopulmonary bypass (CPB) technique that incorporates vacuum assisted venous drainage and arterial return using a centrifugal pump in minimally invasive cardiac surgery (MICS). The technique was performed on 40 patients scheduled to undergo MICS. The proposed CPB technique enables a good operative field to be obtained even through a limited incision through the use of peripheral cannulation using small cannulae. Vacuum pressure was applied to the venous reservoir (-43 +/- 14 mm Hg) to maintain adequate CPB flow (>2.4 L x min-1 x M-2). The effects of CPB on hemolysis were subsequently compared between patients who underwent the proposed procedure (MICS group; n = 6) and a control group who underwent coronary arterial bypass grafting (CABG group; n = 6) with conventional CPB. Plasma free hemoglobin (FHb) increased and plasma haptoglobin (Hp) decreased during CPB in both groups, with no significant difference between the groups. By the next day, FHb had returned to pre-CPB levels whereas Hp remained lower in both groups. Again, these values did not differ significantly between groups. Thus, we conclude that the proposed CPB technique is useful in MICS with acceptable effects on hemolysis.

Analysis of Variance↗
PubMed2000

Hemodynamic effects of milrinone during weaning from cardiopulmonary bypass: comparison of patients with a low and high prebypass cardiac index.

OBJECTIVE: To compare the hemodynamic effects of milrinone during weaning from cardiopulmonary bypass (CPB) in patients with a low pre-CPB cardiac index (CI) <2.5 L/min/m2) and in patients with a high pre-CPB CI (> or =2.5 L/min/m2). DESIGN: Prospective, randomized, double-blind study. SETTING: University hospital. PARTICIPANTS: Forty-eight patients scheduled for elective coronary artery bypass graft surgery. INTERVENTION: Patients were divided into 4 groups: (1) low pre-CPB CI/placebo, (2) low pre-CPB CI/milrinone, (3) high pre-CPB CI/placebo, and (4) high pre-CPB CI/milrinone. Patients received a loading dose of 20 microg/kg of milrinone followed by an infusion of 0.2 microg/kg/min or placebo 15 minutes before the anticipated weaning time. MEASUREMENTS AND MAIN RESULTS: In the low pre-CPB CI/ placebo group, low CIs and high systemic vascular resistances (SVRs) were observed after CPB. High doses of dopamine and dobutamine were needed, and infusion of epinephrine was used in 5 of the 12 patients for hemodynamic support. Milrinone improved CI and reduced SVR in the low pre-CPB CI/milrinone group. Norepinephrine was needed to maintain an adequate systemic blood pressure in 6 of the 12 patients, however. In the high pre-CPB CI/placebo group, satisfactory CIs and SVRs were observed during weaning from CPB with low doses of dopamine and dobutamine. Milrinone significantly increased CI and decreased SVR in the high pre-CPB CI/milrinone group: 10 of the 12 patients had CIs above the upper limit of normal, and 7 patients had SVRs below the lower limit of normal. CONCLUSION: Milrinone was effective during weaning from CPB in patients with a low pre-CPB CI. Milrinone in combination with norepinephrine was a good alternative to epinephrine for the treatment of myocardial dysfunction after CPB.

Aged↗
PubMed2000

ATM protein and p53-serine 15 phosphorylation in ataxia-telangiectasia (AT) patients and at heterozygotes.

ATM (ataxia-telangiectasia mutated) gene plays a central role in the DNA-damage response pathway. We characterized the ATM protein expression in immortalized cells from AT and AT-variant patients, and heterozygotes and correlated it with two ATM-dependent radiation responses, G1 checkpoint arrest and p53-Ser 15 phosphorylation. On Western blots, the full-length ATM protein was detected in eight of 18 AT cases, albeit at 1-32% of the normal levels, whereas a truncated ATM protein was detected in a single case, despite the prevalence among cases of truncation mutations. Of two ataxia without telangiectasia [A-(T)] cases, one expressed 20% and the other approximately 70% of the normal ATM levels. Noteworthy, among ten asymptomatic heterozygous carriers for AT, normal amounts of ATM protein were found in one and reduced by 40-50% in the remaining cases. The radiation-induced phosphorylation of p53 protein at serine 15, largely mediated by ATM kinase, was defective in AT, A(-T) and in 2/4 heterozygous carriers, while the G1 cell cycle checkpoint was disrupted in all AT and A(-T) cases, and in 3/10 AT heterozygotes. Altogether, our study shows that AT and A(-T) cases bearing truncation mutations of the ATM gene can produce modest amounts of full-length (and only rarely truncated) ATM protein. However, this limited expression of ATM protein provides no benefit regarding the ATM-dependent responses related to G1 arrest and p53-ser15 phosphorylation. Our study additionally shows that the majority of AT heterozygotes express almost halved levels of ATM protein, sufficient in most cases to normally regulate the ATM-dependent DNA damage-response pathway.

Ataxia Telangiectasia↗
PubMed2000

The tensegrity model applied to the lens: a hypothesis for the presence of the fiber cell ball and sockets.

The concept of tensegrity refers to the tensional integrity of a system. Such a system mechanically stabilizes itself by balancing the opposing forces of tension and compression. One category of this model involves a 'pre-stressed' condition in which the structural elements are in a state of tensional compression. The other category includes rigid struts that can sustain the opposing forces. The lens of the eye contains epithelial cells that differentiate at the lens equator to fiber cells. With time, these fiber cells are packed into the center of the lens or the lens nucleus. Part of the process of differentiation is the loss of the cellular nucleus and organelles. During maturation of the lens fiber cells, much of the cytoskeleton is lost as a result of proteolysis. As the lens cells mature, ball and socket joints and interlocking ridges appear on the cellular surface. Applying the tensegrity model to the lens, it appears that the lens cells go from prestressed state of tensional compression to the other state that is defined by rigid connections between cells.

Animals↗
PubMed2000

Effect of swallowing training on swallowing disorders in Parkinson's disease.

The purpose of the present study was to determine whether swallowing training improves swallowing function in patients with Parkinson's disease. Ten patients (5 males, 5 females) who had symptoms of dysphagia and 12 healthy volunteers were studied. The initiation time of the swallowing reflex, the "premotor time" (PMT), was calculated from an electromyogram of the submental muscles before and after swallowing training. Patients with Parkinson's disease had a significantly longer PMT (p = 0.0014) than did healthy controls. There was no correlation between PMT and the duration of the disease (r = -0.146; p = 0.6867) or the patient's age (r = 0.602; p = 0.0653). After swallowing training, the patients' PMTs decreased significantly (p = 0.0051).

Aged↗
PubMed2000

Usefulness of a novel enzyme immunoassay for the detection of Helicobacter pylori in feces.

BACKGROUND: In this study we assessed the reliability of a newly developed enzyme immunoassay (HpSA) kit for detecting Helicobacter pylori antigen in stool. METHODS: This study included 309 patients, 147 of whom were defined as positive and 162 as negative by the 13C-urea breath test, rapid urease test, and pathologic findings. From these patients fresh stool specimens were collected for HpSA. RESULTS: When 0.100 was adopted as the cut-off value, in accordance with the manufacturer's recommendations, the sensitivity, specificity, and accuracy of the HpSA were 98.0%, 87.0%, and 92.2%, respectively. However, these values were much improved when a cut-off value of 0.300 was adopted, which was obtained with our receiver-operator characteristics curve; with this value the sensitivity, specificity, and accuracy of HpSA were 93.9%, 95.7%, and 94.8%, respectively. CONCLUSION: These results indicate that HpSA is a highly reliable diagnostic method for H. pylori infection and is useful in confirming eradication.

Antigens, Bacterial↗
PubMed2000

Translocation of Salmonella typhimurium in rats; effect of enteral and parenteral nutrition.

OBJECTIVE: To study translocation of Salmonella typhimurium from ileal loops in rats fed enterally or parenterally. DESIGN: Laboratory experiment. SETTING: University departments of surgery and microbiology, Japan. SUBJECTS: Male Wistar rats and female BALB/C CrSlc mice. INTERVENTIONS: First experiment: portal venous blood and mesenteric lymph nodes from normally fed rats were cultured under aerobic and anaerobic conditions. Second experiment: various concentrations of S. typhimurium (GIFU 12142) were injected intraperitoneally in mice and their survival was monitored. Third experiment: 7 rats were given total parenteral nutrition for 14 days and 6 were given standard chow and water for the same period. Cultures of S. typhimurium were injected into closed ileal loops and portal and vena caval blood and mesenteric lymph nodes were cultured. MAIN OUTCOME MEASURES: Presence and number of bacteria in all samples, and survival of mice. RESULTS: In the first experiment 3/17 blood samples and 9/17 node samples grew enteric bacteria. In the second experiment all the mice died within 5 days. In the third experiment no sample grew bacteria in the enterally fed group, whereas at least some samples from 5/7 rats in the parenterally fed group grew organisms; the difference was significant (p = 0.02). CONCLUSION: Total parenteral nutrition encourages the translocation of S. typhimurium from ileal loops.

Animals↗
PubMed2000

Physicochemical characterization of a new crystal form and improvements in the pharmaceutical properties of the poorly water-soluble antiosteoporosis drug 3,9-bis(N,N-dimethylcarbamoy-loxy)-5H-benzofuro[3,2-c]quinoline-6-one (KCA-098) by solid dispersion with hydroxypropylcellulose.

The present study was undertaken to improve the oral absorption of KCA-098, an antiosteoporosis drug. In this study, the form 2 of KCA-098 was used as a desirable crystal form for pharmaceutical formation among three kinds of crystal forms, 1, 2, and 3. Solid dispersions of KCA-098 with hydroxypropylcellulose (HPC) or poly(vinylpyrrolidone) (PVP) were prepared by the solvent method. The physicopharmaceutical properties of the solid dispersions were characterized by powder x-ray diffraction, FTIR spectroscopy, and differential scanning calorimetry (DSC). The powder x-ray diffractograms suggest that KCA-098 in the HPC-SL solid dispersion existed in a partial crystalline state as a new crystal form that could be produced by recrystallization from the solvent. Dissolution from the solid dispersions was markedly enhanced in comparison with that of the drug alone. The dissolution enhancement was observed to be greater for the solid dispersion with HPC-SL than for that with PVP. The KCA-098/HPC-SL (1:2) solid dispersion capsule showed a 3.5-fold increase in the initial concentration and 2.5-fold increase in initial concentration of dissolved drug after 60 min, compared with the values for a physical mixture of KCA-098 (form 2)/lactose (1:2). The in vivo absorption of the drug was investigated after oral administration of KCA-098 or its solid dispersion. The area under the plasma concentration curve of KCA-098 after oral administration of the KCA-098/HPC-SL (1:2) solid dispersion capsule was three-fold greater than that for the drug itself.

Absorption↗
PubMed2000

A family of cAMP-response-element-related DNA sequences with meiotic recombination hotspot activity in Schizosaccharomyces pombe.

The heptamer sequence ATGACGT is essential for activity of the M26 meiotic recombination hotspot in the ade6 gene of Schizosaccharomyces pombe. Hotspot activity is associated with binding of the heterodimeric transcription factor Atf1.Pcr1 to M26. We have found that the sequences (C/T/G) TGACGT also bound Atf1.Pcr1 and acted as meiotic hotspots, but unlike M26 they must be followed by A or C for Atf1.Pcr1 binding and hotspot activity. The basis of the hotspot activity of CTGACGTA (ade6-3013) appears to be identical to that of M26: hotspot activity of both sequences was abolished in cells mutant for atf1, pcr1, spc1, or wis1 and was undetectable in mitotic recombination and in meiotic recombination when located on a plasmid. Both hotspot sequences were sites of micrococcal nuclease hypersensitivity in meiotic chromatin, suggesting that they create an open chromatin structure during meiosis at the site of the hotspots. The newly identified hotspot sequences (C/T/G)TGACGT(A/C) and M26 are closely related to the cAMP response element (CRE) consensus sequence for binding of cAMP-responsive transcription factors such as Atf1.Pcr1, suggesting a link between transcription and meiotic recombination. These results significantly expand the list of identified sequences with meiotic recombination hotspot activity in S. pombe from a single sequence to a family of CRE-related sequences.

Base Sequence↗
PubMed2000

Lung carcinoma with polypoid growth in the main pulmonary artery: report of two cases.

Invasion into the lumen of the main pulmonary artery is an uncommon mode of extension in lung carcinoma and its prognostic significance remains unclear. We describe here two resected cases of lung carcinoma that showed such a rare tumor spread. Although a preoperative evaluation, such as angiography or perfusion scan of the lung, had shown a significant decrease in circulation, we could not diagnose the intraluminal tumor growth preoperatively. Pneumonectomy was finally needed to perform a curative operation. The tumors were centrally located and showed polypoid growth in the main pulmonary artery. Postoperative pathological examination revealed the tumors to be adenosquamous carcinoma of the lung in both cases. No intrapulmonary metastases were detected. One patient is doing well with no signs of recurrence after a follow-up period of 10 years. Although intra-arterial polypoid growth of lung carcinoma is extremely rare, such tumor extension should be considered preoperatively to perform a curative surgical resection, especially when the tumor is centrally located. While arterial invasion is generally an ominous prognostic factor, curative surgical resection would offer a good prognosis, even for lung carcinoma invading the main pulmonary arterial trunk.

Aged↗