Search PubMed⌕ Search

Biomedical subjects

M Kato

Publications and source records attributed to M Kato.

At least 541 records · Page 30Linked to original sources
PubMed1999

Adenosine 5'-triphosphate induced dilation of human coronary microvessels in vivo.

OBJECT: This study was performed to compare the coronary microvascular response to adenosine 5'-triphosphate (ATP) with the response to adenosine in humans. METHODS: Coronary blood flow velocity was determined using a Doppler flow wire. After intracoronary nitroglycerin infusion, intracoronary bolus injections of adenosine (20 microg) and ATP (20 microg) were performed to induce reactive hyperemia. PATIENTS: Twenty-nine patients (23 men and 6 women, mean age: 63+/-9 years) with coronary artery disease and risk factors for coronary atherosclerosis were studied. RESULTS: Coronary flow reserve in response to ATP was similar to that for adenosine (2.7+/-0.7 vs. 2.7+/-0.7). However, the duration of ATP-induced vasodilation was longer than that of adenosine-induced dilation (39+/-25 seconds vs. 26+/-12 seconds, p<0.0001). The coronary flow reserve obtained with either ATP or adenosine was significantly reduced in the interventioned arteries compared with non-stenosed arteries. The coronary flow reserve obtained with ATP was similar to that obtained with adenosine in both artery groups. The duration of the vasodilator effect of ATP was significantly greater than that of adenosine in both artery groups. CONCLUSION: These results suggest that ATP induces maximal dilation of coronary microvessels, most likely through an endothelium-independent mechanism. The degradation of ATP to adenosine 5'-monophosphate (AMP) and adenosine, as well as the direct action of ATP on A2-adenosine receptors may be responsible for the dilation. We conclude that coronary flow reserve can be determined safely with intracoronary ATP administration.

Adenosine↗
PubMed1999

Idiopathic verapamil-sensitive left ventricular tachycardia complicated by right ventricular outflow tract ventricular tachycardia and ventricular fibrillation.

Idiopathic ventricular tachycardias (VTs) are generally divided into those arising from the right ventricle and those arising from the left ventricle. There has been few reports of two morphologically distinct VT occurring in patients with no apparent structural heart disease. We report a patient with verapamil-sensitive left VT with a right bundle branch block pattern that spontaneously changed to VT with a left bundle branch block pattern. Ventricular fibrillation was induced by the application of programmed stimulation. Although it is unclear if our patient with pleomorphic VT has ventricular vulnerability, it is necessary to investigate further and follow him carefully.

Adult↗
PubMed1999

The role of nitric oxide in bradykinin-induced dilation of coronary resistance vessels in patients with hypercholesterolemia.

OBJECT: In hypercholesterolemic patients, acetylcholine- and substance P-mediated endothelium-dependent dilation of the coronary resistance vessels is impaired due to decreased nitric oxide production. However, it is not clear if bradykinin-induced coronary vasodilation is impaired in these patients. We investigated whether the endothelium-dependent dilation of coronary resistance vessels mediated by bradykinin is impaired in patients with hypercholesterolemia and, if so, whether this impairment is caused by a decreased production of nitric oxide. METHODS: We examined the coronary vascular responses to acetylcholine and bradykinin. The vascular responses to bradykinin were also assessed after N(G)-monomethyl-L-arginine was infused to inhibit nitric oxide production. Drugs were infused into the left coronary ostium and coronary blood flow (CBF) and coronary vascular resistance were evaluated by quantitative angiography and Doppler flow velocity measurements. PATIENTS: Twelve hypercholesterolemic patients and 11 control patients with angiographically normal coronary arteries were studied. RESULTS: The vasodilator responses to acetylcholine and bradykinin were reduced in hypercholesterolemic patients compared with control patients (p<0.005 and p<0.04, respectively, by two-way analysis of variance (ANOVA)). The CBF responses to acetylcholine and bradykinin were significantly correlated (r=0.56; p<0.01). Bradykinin-induced dilation was similar in hypercholesterolemic patients and control patients after inhibition of nitric oxide. CONCLUSION: These results suggest that the bradykinin-mediated endothelium-dependent dilation of coronary resistance vessels may be impaired due to depressed nitric oxide production in patients with hypercholesterolemia.

Acetylcholine↗
PubMed1999

Migrated disc in the lumbar spinal canal--case report.

A 49-year-old man who had complained of back pain for 20 years presented with numbness and pain in his left leg persisting for 6 weeks. Magnetic resonance imaging demonstrated a peripherally enhanced intraspinal mass at the L-3 level. The mass was completely removed. The operative and histological findings revealed degenerated disc fragments surrounded by granulation tissue. His symptoms were completely relieved. Migrated disc should be included in the differential diagnosis of patients with a long history of back pain and an intraspinal mass.

Diagnosis, Differential↗
PubMed1999

NASDA aquatic animal experiment facilities for Space Shuttle.

National Space Development Agency of Japan (NASDA) has been developed aquatic animal experiment facilities for space experiments using NASA Space Shuttle. Vestibular Function Experiment Unit (VFEU) has been firstly designed and developed for Spacelab-J mission (STS-47), and 8 days space experiment with carp has been performed. Following, the VFEU, Aquatic Animal Experiment Unit (AAEU) has been developed to accommodate small aquatic animals second International Microgravity Laboratory mission (IML-2, STS-65). Four kinds of space experiments with goldfish, medaka, newt, and newt eggs have been performed for 15 days mission duration. Then, VFEU has been improved to accommodate marine fish under low temperature condition for Neurolab (STS-90) and STS-95 missions. 17 days (STS-90) and 9 days (STS-95) experiments with oyster toadfish have been performed by using the VFEU. This report summarizes the outline of these aquatic animal experiment facilities.

Animals↗
PubMed1999

VFEU water quality control in STS-95 mission.

In STS-95 Space Shuttle mission, an aquatic animal research facility, Vestibular Function Experiment Unit (VFEU), was flown to perform neurobiological experiment with marine fish, oyster toadfish. For this purpose, we have developed a sea water purification system using highly active nitrifying bacteria at low temperature. With this system, the water quality in the VFEU was maintained in sufficient condition to keep the toadfish in healthy state for 9 days of the mission. This report summarizes the efficiency of the filter system based on the results from pre-flight bacterial preparation, water analysis of samples taken during flight, and the post-flight analysis of the bacterial filter.

Ammonia↗
PubMed1999

Water quality management for low temperature marine fishes in space.

Vestibular Function Experiment Unit (VFEU), one of the Spacelab facility flown in Neurolab mission (STS-90) in April, 1998, was to support neurophysiological research using a marine fish, Opsanus tau (oyster toadfish). The functions of the VFEU were primarily a quality management of environmental water during the mission at 14 degrees C and for acquiring physiological signals from implanted micro-electrodes in the otolith nerves as well as the spatial acceleration of the fish. A key element of the life support system was a balanced biological filter containing two types of nitrifying bacteria, Nitrosomonas for ammonia oxidization and Nitrobacter for nitrite oxidization. Although the 16 days mission was successful, two toadfishes died in late phase of the mission. Ammonium concentration in those two life support systems elevated to remarkably high level at the end of the mission whereas the other two indicated very low. This report summarizes the results of the water quality management of the VFEU during the Neurolab mission based on analysis of water samples taken during the flight and those taken prior and just after the flight.

Animals↗
PubMed1999

Current trends in cognitive rehabilitation for memory disorders.

Progress in the neuropsychology of memory disorders has provided a foundation for development of cognitive rehabilitation for amnesic patients. Accumulating evidence in the past two decades suggested that certain training techniques could be beneficial to many amnesic patients, such as teaching and acquisition of domain-specific knowledge, motor coding, reality orientation, and meta-cognition improvement. In this article we review and discuss the current trends in cognitive rehabilitation of memory disorders and provide a future direction in this emerging field. In addition, our experience in the successful rehabilitation of Korsakoff syndrome patients is also introduced.

Alcohol Amnestic Disorder↗
PubMed1999

Novel small molecule nonpeptide aminopeptidase n inhibitors with a cyclic imide skeleton.

A novel series of small molecule nonpeptide aminopeptidase N (APN) inhibitors with a N-phenylphthalimide or N-phenylhomophthalimide skeleton were prepared. Evaluation of their protease inhibitory activities revealed that (i) some N-phenylphthalimide analogs are potent APN inhibitors, but they are also inhibitors of another protease, dipeptidylpeptidase IV (DPP-IV), and (ii) some N-phenylhomophthalimide analogs, including 2-(2,6-diethylphenyl)-1,2,3,4-tetrahydroisoquinoline-1,3-dione (PIQ-22), are potent and specific inhibitors of APN without DPP-IV-inhibitory activity. The structure-activity relationship studies of N-phenylphthalimides and N-phenylhomophthalimides are reviewed. PIQ-22 showed potent tumor-cell invasion-inhibitory activity.

Antineoplastic Agents↗
PubMed1999

Bacterial contamination of ready-to-eat foods and fresh products in retail shops and food factories.

Raw vegetables cut for salad, cooked salad, cooked rice, boiled noodles, bean curd, and cooked Japanese foods were purchased in 27 retail shops in Tokyo. Intact vegetables before being processed and ready-to-eat fresh salad products were obtained from two food factories located in the suburbs of Tokyo. Two hundred thirty-eight retail samples, 137 samples of intact vegetables, and 159 samples of fresh products were examined for aerobic plate count (APC), coliforms, Escherichia coli, Listeria spp., Staphylococcus aureus, and Bacillus cereus. The APC of retail foods were 2.1 to 5.7 log CFU/g, and the range for the coliforms was 0.1 to 2.3 log CFU/g. The APC and coliform values showed that the raw vegetables cut for salad were the most heavily contaminated among the six kinds of ready-to-eat foods examined. Although L. monocytogenes was not detected, two samples of raw vegetables and five kinds of cooked foods yielded Listeria spp. S. aureus was detected in one sample of Japanese cooked food. The APC of the intact vegetables were 2.9 to 7.3 log CFU/g upon arrival and 2.2 to 7.2 log CFU/g after 3 days storage at 10 degrees C. The APC of the fresh products were 3.4 to 7.6 log CFU/g upon arrival and 4.7 to 8.7 log CFU/g after 3 days storage at 10 degrees C. The isolation rates for coliforms were 6.1 to 50% for intact vegetables and 50 to 66.7% for fresh products. E. coli was detected only in the fresh products. B. cereus was isolated from 20.1% (17 of 81) of the intact vegetables and 9.2% (8 of 87) of the fresh products.

Bacteria↗
PubMed1999

Neuroendocrine carcinoma of the posterior mediastinum: a possible primary lesion.

A paravertebral mass was noted in the posterior mediastinum in a 47-year-old man. Microscopically, the tumor showed solid and trabecular patterns and consisted of poorly differentiated atypical cells that often formed Flexner-Wintersteiner rosettelike glands. Immunohistochemically, the tumor cells expressed both epithelial and neuroendocrine markers, including cytokeratin (AE1/3), carcinoembryonic antigen, epithelial membrane antigen, neuron-specific enolase, chromogranin A, and synaptophysin, but were negative for CD99 (MIC2). Ultrastructurally, numerous desmosomes and neurosecretory granules were identified in the tumor cells. The present lesion was a primary neuroendocrine carcinoma of the posterior mediastinum-an unusual site for such a lesion.

Biomarkers, Tumor↗
PubMed1999

[The appropriate time for the assessment of Helicobacter pylori eradication].

As all of the guidelines on the management of H. pylori infection suggest, the assessment of the eradication is generally performed at least 4 weeks after the completion of eradication treatment. However, H. pylori occasionally re-appears after one month, even the successful eradication was confirmed by the guideline. In this study, we investigated the appropriate time for the assessment of H. pylori eradication, mainly by using 13C urea breath tests (UBT) as a positive standard. From July 1992 to December 1997, 386 patients with H. pylori infection received eradication treatments. The presence of H. pylori was assessed by rapid urease test, UBT, culture and histologic examination. Eradication of the bacteria was determined by the negative results in all of these four tests. At 4 weeks after completion of therapy, 312 cases (80.8%) were judged as being free of H. pylori. Mean observation period was up to 12 months, and 113 cases were followed up to more than 1 year, and 50 cases were followed up to more than 2 years. H. pylori had re-appeared in 3 cases after 3 months, 1 case after 6 months, 2 cases after 12 months, and 1 case 24 months after the treatment, respectively. For the purpose of more accurate diagnosis, the assessment of eradication of H. pylori should be performed at 1 year after the completion of therapy. Since all the recrudescence could be diagnosed with UBT earlier and be confirmed by the other tests later, UBT is recommended as a useful methods in the assessment of Helicobacter pylori eradication.

Adult↗
PubMed1999

Multiple myeloma preceding the development of chronic myelogenous leukemia.

A case of a 70-year-old man who first developed multiple myeloma and then chronic myelogenous leukemia (CML) within a 3-year period is documented. The patient, with monoclonal hypergammopathy, was diagnosed with smoldering myeloma with IgG-kappa and Bence Jones protein kappa paraproteinemia. No chemotherapy was given for the myeloma until progressive leukocytosis developed after approximately 3 years. This was found to be due to Philadelphia chromosome positive CML. A reverse transcription-polymerase chain reaction assay did not reveal BCR/ABL mRNAs when the myeloma was first diagnosed. The occurrence of 2 distinct hematologic malignancies in the same patient suggests either a different clonal evolution from a common pluripotent malignant stem cell since the CML stem cell also involves the B-lymphoid lineage, a coincident complication of the 2 hematological malignancies, or the coexistence of 2 distinct malignancies due to the same genetic background and/or exposure to similar carcinogenic agents. The literature provides support for the existence of a relationship between multiple myelomas and CML.

Aged↗
PubMed1999

Cerebrospinal fluid tau protein levels in demented and nondemented alcoholics.

The tau protein levels in cerebrospinal fluid (CSF-tau) were examined in 27 patients with alcohol dependence (20 demented and 7 nondemented), 36 age and dementia severity-matched patients with Alzheimer's disease (AD), and 23 age-matched normal control subjects. The CSF-tau levels in the demented alcoholic group (alcohol-induced organic brain disorders, 25.4 +/- 10.2 pg/ml) was significantly lower (p < 0.0001) than that in the AD group (96.1 +/- 53.3 pg/ml), but not significantly different from that in the nondemented alcoholics (18.1 +/- 10.2 pg/ml) or the controls (19.2 +/- 12.9 pg/ml). Using a 44.9 pg/ml as a cut-off value (mean + 2 SD of the normal control group), only one patient with alcohol-induced organic brain disorders exceeded the value, whereas 3 of 36 of the AD group showed CSF-tau levels less than this level. These findings suggest that alcohol-induced organic brain disorders are a group of dementias that are characterized by normal CSF-tau levels, and that the CSF examination for tau in combination with other clinical findings may help in differentiating alcohol-induced organic brain disorders from AD.

Adolescent↗
PubMed1999

Three pollination guilds and variation in floral characteristics of Bornean gingers (Zingiberaceae and Costaceae).

The pollinators of 29 ginger species representing 11 genera in relation to certain floral morphological characteristics in a mixed-dipterocarp forest in Borneo were investigated. Among the 29 species studied, eight were pollinated by spiderhunters (Nectariniidae), 11 by medium-sized Amegilla bees (Anthophoridae), and ten by small halictid bees. These pollination guilds found in gingers in Sarawak are comparable to the pollination guilds of neotropical Zingiberales, i.e., hummingbird-, and euglossine-bee-pollinated guilds. Canonical discriminant analysis revealed that there were significant correlations between floral morphology and pollination guilds and suggests the importance of plant-pollinator interactions in the evolution of floral morphology. Most species in the three guilds were separated on the plot by the first and second canonical variables. Spiderhunter-pollinated flowers had longer floral tubes, while Amegilla-pollinated flowers had wider lips than the others, which function as a platform for the pollinators. Pistils and stamens of halictid-pollinated flowers were smaller than the others. The fact that gingers with diverse morphologies in a forest with high species diversity were grouped into only three pollination guilds and that the pollinators themselves showed low species diversity suggests that many species of rare understory plants have evolved without segregating pollinators in each pollination guild.

Journal Article↗
PubMed1999

[Comparison of Tandem-R PSA and Markit-M PA in the diagnosis of prostate cancer].

The Tandem-R PSA (TR) assay was compared with the Markit-M PA (MM) assay in the diagnosis of the prostate cancer. In patients with a serum prostate specific antigen (PSA) level higher than the cut-off values measured by either the TR assay or the MM assay (4.1 ng/ml and 3.7 ng/ml, respectively), or a suspicious digital rectal examination, sextant biopsy of the prostate was performed. Among 227 patients undergoing biopsy, 64 patients were diagnosed as having prostate cancer. There was a significant difference of serum PSA values between patients with and without prostate cancer in either assay. There was no significant difference between the assays with respect to diagnosing according to prostate cancer using receiver operating characteristic analysis. The correlation between TR and MM in 150 men with a serum Tandem-R PSA below 10 ng/ml was Y = 1.12X + 3.745 (R = 0.68, p < 0.001). The correlation coefficient for the relationship between TR and MM was only 0.68, indicating a poor correlation. Four of the 15 patients with MM values below 4.0 ng/ml calculated by transformation from MM to TR values had prostate cancer. This suggested that conversion of MM values to TR values in the low PSA range presents problems.

Aged↗