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Biomedical subjects

M Yoshimura

Publications and source records attributed to M Yoshimura.

At least 73 records · Page 4Linked to original sources
PubMed2000

Comparison of the risk factors for coronary artery spasm with those for organic stenosis in a Japanese population: role of cigarette smoking.

We compared the risk factors for coronary spasm with those for coronary atherosclerosis in 183 patients with coronary spasm, 132 patients with coronary organic stenosis, and 224 control subjects with chest pain syndrome. Our findings confirmed that, when compared with controls, age, gender, total cholesterol, LDL-cholesterol, hypertension, diabetes mellitus, and cigarette smoking are all significant risk factors for coronary organic stenosis. On the other hand, only cigarette smoking proved to be a significant risk factor for coronary spasm. Also, when compared between coronary spasm group and coronary organic stenosis group, the incidence of cigarette smoking in males was significantly higher in the coronary spasm group than in the coronary organic stenosis group. We conclude that cigarette smoking is a crucial risk factor for coronary spasm. On the other hand, serum lipid levels and the incidence of hypertension and diabetes mellitus were within the normal ranges in the coronary spasm patients and were thus poorly associated with coronary spasm. These results showed that the risk factors for coronary spasm differ significantly from those for atherosclerosis-based coronary stenosis in the Japanese. Among the risk factors for coronary atherosclerosis (organic stenosis) smoking alone was a significant preventable risk factor for coronary artery spasm.

Aged↗
PubMed2000

Difference in fibrinolytic activity between multivessel coronary spasm and one-vessel coronary spasm.

Plasminogen activator inhibitor activity was higher in 18 patients with multivessel spasm than in 20 patients with 1-vessel spasm and in 22 control patients. Tissue plasminogen activator antigen was also higher in patients with multivessel spasm than in those with 1-vessel spasm and control patients. The increased plasminogen activator inhibitor activity in patients with multivessel spasm indicates that the fibrinolytic system is more impaired in such patients than in those with 1-vessel coronary spasm; this may be related to the higher incidence of refractory angina during hospitalization and cardiac events during the follow-up period.

Angina Pectoris↗
PubMed2000

Gallium-67 scintigraphic findings in a patient with breast lymphoma complicated with Sjögren syndrome.

We report here a patient with mucosa associated lymphoid tissue (MALT)-lymphoma of the breast complicated with Sjögren syndrome. It is speculated that Ga-67 could accumulate not only in lymphoma lesions but also in benign lymphoproliferative locations of Sjögren syndrome. Gallium-67 scintigraphy might be useful for the diagnosis and therapeutic monitoring of MALT-lymphoma complicated with Sjögren syndrome.

Adult↗
PubMed2000

Primary biliary cirrhosis associated with idiopathic retroperitoneal fibrosis.

Idiopathic retroperitoneal fibrosis (IRF) and primary biliary cirrhosis (PBC) are distinct clinical disorders which rarely occur in the same patient. We report a 79-year-old man with the coexistence of both conditions. The patient had antibodies to both centromere and mitochondria, as indicated by indirect immunofluorescence. Diagnoses of IRF and PBC were confirmed histologically. Although the association between IRF and PBC is obscure, IRF may be involved in many autoimmune diseases associated with PBC.

Aged↗
PubMed2000

Surgical treatment for chronic pleural empyema.

Various surgical procedures have been developed in an attempt to alleviate the significant problems caused by chronic pleural empyema. The present study evaluates our 11-year experience of employing a number of therapeutic approaches for chronic empyema. Between 1987 and 1997, 45 consecutive patients underwent treatment for chronic empyema at our hospitals. They comprised 21 patients (47%) presenting with post-tuberculosis, 11 (24%) receiving cancer therapy including pulmonary resection, and 13 (29%) with postpneumonic empyema. Omentopexy, lung resection, and thoracoscopic surgery were performed in 10 (22%), 5 (11%), and 4 (9%) patients, respectively. Poor results of treatment were observed in two of the patients with post-tuberculous empyema, and three of the patients treated for cancer died of recurrence. The other 40 patients remain symptom-free. An improvement in quality of postoperative life was revealed by the exercise test rather than by static spirometry. Optimal therapy for chronic empyema requires selection of the most appropriate first and staged procedures for each patient. Moreover, lung resection should be minimal. In a critical state, open thoracostomy must be performed as the first procedure, while omentopexy or thoracoplasty should be restricted to selected cases. Dead space and minor air leakage may safely be left behind. A video-assisted procedure can be selected for postpneumonia empyema.

Adult↗
PubMed2000

Analgesic mechanism of calcitonin.

Calcitonin is employed in clinical treatment to improve bone mass in osteoporosis and to relieve its accompanying pain, but its analgesic mechanism is still unclear. Using ovariectomized (OVX) rats that are well known as an animal model of osteoporosis, the antinociceptive effect of elcatonin ([Asu] eel calcitonin, ECT), a synthetic derivative of eel calcitonin, was examined with the tail-withdrawal nociceptive test. Prolonged hyperalgesia was induced by OVX, and the antinociceptive effect of ECT was proved because peripherally and repeatedly administered ECT improved hyperalgesia. This effect of ECT was completely abolished by injections of p-chlorophenylalanine (PCPA), an inhibitor of serotonin biosynthesis, suggesting that the serotonergic system may be involved in antinociception. Spinal cord slices that retained an attached dorsal root were prepared, and blind whole-cell recordings were made from substantia gelatinosa (SG, lamina II) for electrophysiological analyses of a relationship between the effect of ECT and the serotonergic system. The descending serotonergic fibers, one of the inhibitory systems for nociceptive transmission, originate from the nucleus raphe magnus and terminate preferentially on SG of the spinal dorsal horn. Excitatory postsynaptic currents (EPSCs) evoked by dorsal root stimulation were then recorded from SG neurons, and the effects of serotonin on the EPSCs were compared in sham-operated and OVX rats. In addition, influence of ECT administration to OVX rats on the effects of serotonin was also examined. Glutamatergic short- and long-latency EPSCs, mediated by A delta and C afferent fibers, respectively, were observed after stimulation of the dorsal root, and both were depressed in amplitude by serotonin in sham rats, whereas only A delta-mediated EPSCs but not C-mediated were inhibited in OVX rats. Interestingly, C-mediated EPSCs were inhibited by serotonin in ECT-treated OVX as well as sham rats. A relationship between the fact that OVX induced hyperalgesia and that ECT alleviated this hyperalgesia was well correlated with changes in serotonergic inhibition of C-mediated EPSCs. These results suggest an alteration in the spinal serotonergic receptors that control the nociceptive transmission. Receptor-binding assay using spinal membranes and [3H]-8-OH-DPAT as a radioactive ligand was used to assess the change in the receptors. Although the level of [3H]-8-OH-DPAT-binding sites was decreased in OVX rats compared with sham rats, this reversed to the normal level in ECT-treated OVX rats. All the results strongly suggest that the behavioral and electrophysiological changes may be caused by an alteration in the level of spinal serotonergic receptor expression.

Analgesics↗
PubMed2000

Effect of apolipoprotein E allele epsilon4 on the initial phase of amyloid beta-protein accumulation in the human brain.

Deposition of amyloid ss-protein (Ass), a hallmark of Alzheimer's disease, occurs to some extent in the brains of most elderly individuals. We sought to learn when Ass deposition begins and how deposition is affected by apolipoprotein E allele epsilon4, a strong risk factor for late-onset Alzheimer's disease. Using an improved extraction protocol and specific enzyme-linked immunosorbent assay, we quantified the levels of Ass40 and Ass42 in the insoluble fractions of brains from 105 autopsy cases, aged 22 to 81 years at death, who showed no signs of dementia. Ass40 and Ass42 were detected in the insoluble fractions from all of the brains examined; low levels were even found in the brains of patients as young as 20 to 30 years of age. The incidence of significant Ass accumulation increased age-dependently, with Ass42 levels beginning to rise steeply in some patients in their late 40's, accompanied by much smaller increases in Ass40 levels. The presence of the apolipoprotein E epsilon4 allele was found to significantly enhance the accumulation of Ass42 and, to a lesser extent, that of Ass40. These findings strongly suggest that the presence of epsilon4 allele results in an earlier onset of Ass42 accumulation in the brain.

Adult↗
PubMed2000

Survival related to lymph node involvement in lung cancer after sleeve lobectomy compared with pneumonectomy.

OBJECTIVE: The purpose of this study was to compare the outcomes after sleeve lobectomy and pneumonectomy for patients with non-small cell lung cancer distributed according to their nodal involvement status. METHODS: Of 1172 patients in whom primary non-small cell lung carcinoma, including mediastinal lymph nodes, was completely excised, 151 patients underwent sleeve lobectomy and 60 underwent pneumonectomy. For bias reduction in comparison with a nonrandomized control group, we paired 60 patients undergoing sleeve lobectomy with 60 patients undergoing pneumonectomy by using the nearest available matching method. RESULTS: The 30-day postoperative mortality was 2% (1/60) in the pneumonectomy group and 0% in the sleeve lobectomy group. Postoperative complications occurred in 13% of patients in the sleeve lobectomy group and in 22% of those in the pneumonectomy group. Local recurrences occurred in 8% of patients in the sleeve lobectomy group and in 10% of those in the pneumonectomy group. The overall 5- and 10-year survivals for the sleeve lobectomy group were 48% and 36%, respectively, whereas those for the pneumonectomy group were 28% and 19%, respectively (P =.005). Multivariable analysis showed that the operative procedure, T factor, and N factor were significant independent prognostic factors and revealed that survival after sleeve lobectomy was significantly longer than that after pneumonectomy (P =.03). CONCLUSIONS: These data suggest that sleeve lobectomy should be performed instead of pneumonectomy in patients with non-small cell lung cancer regardless of their nodal status whenever complete resection can be achieved because this is a lung-saving procedure with lower postoperative risks and is as curative as pneumonectomy.

Carcinoma, Non-Small-Cell Lung↗
PubMed2000

Differential localization of 5-hydroxytryptamine3 and 5-hydroxytryptamine4 receptors in the human rectum.

The functions of the 5-hydroxytryptamine3 (5-HT3) and 5-hydroxytryptamine4 (5-HT4) receptors in gastrointestinal tract are complex depending on the species and anatomical regions, and the localization of these receptors in the human rectum was unclear. We examined the localization of the 5-HT3 and 5-HT4 receptors in human rectum by in vitro receptor autoradiography using [125I](S)iodozacopride and [125I] SB207710 as a ligand, respectively. Specific [125I](S)iodozacopride binding sites were clearly evident in the myenteric plexus, whereas, low levels of [125I]SB207710 binding sites were distributed over the muscle but not to the myenteric plexus. The 5-HT3 receptor located on the myenteric plexus and the 5-HT4 receptor on the smooth muscle may participate in contractility and relaxation of human rectum, respectively.

Aged↗
PubMed2000

Prevention of collagen-induced arthritis in DBA/1 mice by oral administration of AZ-9, a bacterial polysaccharide from Klebsiella oxytoca.

Collagen-induced arthritis (CIA) is an excellent model of rheumatoid arthritis (RA) in humans that is induced in DBA/1 mice immunized with bovine type II collagen (CII). Here, we report that the induction of CIA was effectively suppressed by oral administration of AZ-9, a purified polysaccharide with the average molecular weight of approximately 200 kDa that was produced by a soil bacterium, Klebsiella oxytoca. When AZ-9 was administered at 125-250 mg/kg/day orally for 9 consecutive days after immunization with CII followed by its administration every 3 days, resulted in a marked reduction of the incidence and the severity of CIA. The serum level of anti-CII IgG2a and the production of IFN-gamma and IL-12 in the draining lymph node (LN) cells were significantly lower in AZ-9-administered mice than the untreated control. These findings suggest that orally administered AZ-9 suppressed CIA through attenuating a Th1-type response to CII. AZ-9 could be fragmented into smaller molecules (3-4 kDa) without losing its suppressive activity.

Administration, Oral↗
PubMed2000

Interaction between nitric oxide and substance P on heat-induced inflammation in rat paw.

To elucidate the interaction between nitric oxide (NO) and substance P (SP) in neurogenic inflammatory responses, we measured the change in the degree of Evans blue leakage and NO levels in perfusate from the subcutaneous space in the rat instep following noxious heat stimulation (47 degrees C for 30 min). Furthermore, the effects of drugs affecting nitric oxide synthase were examined. Noxious heat stimulation caused on an increase in NOx, or NO2- and NO3- into the perfusate in parallel with plasma extravasation. Nw-nitro-L-arginine methylester (L-NAME: 100 mg/kg once daily.) intraperitoneally (i.p.) given five times (chronic treatment) significantly suppressed the increase in Evans blue extravasation induced by heat stimulation, whereas acute treatments with L- and D-NAME (100 mg/kg once, i.p.) did not show any significant effect. NO release induced by heating also was significantly suppressed by chronic pretreatment with L-NAME, but not by acute treatment. SP (10(-5) M) applied into the perfusate caused a remarkable increase in the NOx release into the perfusate. Intra-arterial injection of RP67580 (1 mg/kg) on the perfused side, but not SR48968 (1 mg/kg), significantly attenuated the increases in Evans blue leakage and NOx release during heat stimulation. These results suggest that heat-induced SP release from the peripheral endings of small-diameter afferent fibers causes NO generation through NK-1R, and that this gas act to elicit or enhance inflammatory responses.

Analgesics↗
PubMed2000

Alteration in synaptic inputs through C-afferent fibers to substantia gelatinosa neurons of the rat spinal dorsal horn during postnatal development.

The change in synaptic inputs through primary afferent C- and A-fibers during postnatal development was examined in substantia gelatinosa neurons of a rat spinal cord slice with an attached L5 dorsal root by use of the blind whole-cell patch-clamp technique; the synaptic responses were compared between the slices obtained from immature (postnatal days 21-23) and mature (postnatal days 56-60) male rats. The mono- and/or polysynaptic afferent inputs were monitored by recording glutamatergic excitatory postsynaptic currents and potentials evoked by stimulating C- and A-fibers, the identification of which was based on the values of threshold stimulus intensity and of the conduction velocity of the fibers, determined by intracellular recordings from dorsal root ganglion neurons. Immature substantia gelatinosa neurons received synaptic inputs through Abeta-, Adelta- and C-afferents, with proportions of 51%, 46% and 36%, respectively. In mature substantia gelatinosa neurons, C- and Adelta-afferent inputs were increased in number (to 84% and 86%, respectively), while Abeta-inputs were decreased to 9%. In both immature and mature rats, repetitive stimulation of C-afferents did not elicit any slow responses, which are longer in duration than the monosynaptic excitatory postsynaptic currents, although C-fibers are known to contain not only excitatory amino acids, but also neuropeptides such as substance P, which is thought to be involved in the production of slow responses. These results indicate that both C- and Adelta-afferents innervating substantia gelatinosa neurons are reorganized following maturation, accompanied by a withdrawal or elimination of Abeta-fibers from the substantia gelatinosa, probably due to a competition among the fibers during development. In spite of the developmental increase in C-fiber inputs, mature as well as immature substantia gelatinosa neurons did not display any slow synaptic responses, which appear to be mediated by transmitters other than excitatory amino acids.

Action Potentials↗
PubMed2000

Diffuse intimal thickening of coronary arteries in patients with coronary spastic angina.

OBJECTIVES: The purpose of this study was to evaluate the extent of atherosclerotic changes in angiographically normal coronary arteries using intravascular ultrasound (IVUS) technique in patients with coronary spastic angina. BACKGROUND: Nitric oxide activity was shown to be decreased in coronary arteries of patients with coronary spastic angina (CSA). Decrease in nitric oxide causes arterial intimal hyperplasia or thickening. However, it remains unclear whether intimal thickening is diffusely present in coronary arteries of patients with CSA. METHODS: The IVUS study was performed in 26 patients with CSA and with normal coronary angiograms and in 31 control subjects in whom age and gender was matched with those in patients with CSA. RESULTS: Compared with control subjects, patients with CSA had significantly larger percent intima + media area (%I + M area), intima + media area and maximal intima + media thickness in all of proximal, middle and distal segments (p<0.01, respectively). Lumen area was comparable between these groups. The presence of spasm was the most powerful independent predictor of increase in percent intima + media area, in multiple-regression analysis with the traditional risk factors as covariates. CONCLUSIONS: Intimal thickening existed entirely in a coronary artery in patients with CSA and with normal angiograms, independently of other traditional risk factors. The diffuse intimal thickening in the spasm coronary arteries is intimately related with coronary spasm.

Aged↗
PubMed2000

A molecular description of the gelation mechanism of konjac mannan.

A molecular level description of the time course of the gelation of the polysaccharide konjac mannan (KM) is presented and the role of alkali addition is considered in detail. NMR relaxometry is utilized as a complementary methodology to mechanical spectroscopy in order to probe events occurring as a prelude to network formation, and high-resolution NMR is used to follow the deactetylation process. It is shown that the addition of alkali plays an important solubilizing role in addition to facilitating the deacetylation of the chain. Deacetylation is important both in reducing the inherent aqueous solubility of the polymer and in progressively negating the alkali-induced polyelectrolytic nature of the polysaccharide chain via reaction induced pH changes. It is proposed that observed induction periods following alkali addition (during which the elastic modulus does not rise) are not simply deacetylation delays but are related to the aggregation kinetics of the deacetylated material.

Algorithms↗
PubMed2000

Role of nitric oxide in haemodialysis hypotension.

To investigate the possible involvement of nitric oxide (NO) in haemodialysis hypotension, we measured plasma concentrations of nitrate anion (NO3-), a metabolite of NO, in 114 patients undergoing maintenance haemodialysis. Mean plasma NO3- concentrations before dialysis were greater in subjects with lower blood pressure (155 +/- 16 micromol L-1) than in those with middle (117 +/- 8 micromol L-1) or higher blood pressure (105 +/- 12 micromol L-1) before dialysis. Further, mean plasma NO3- concentrations before dialysis were greater in subjects with lower blood pressure (186 +/- 13 micromol L-1) than in those with middle (112 +/- 7 micromol L-1) or higher blood pressure (64 +/- 11 micromol L-1) after dialysis. Plasma NO3- concentrations before dialysis were inversely correlated with mean blood pressure before dialysis (r=0.318, P=0.0006), and showed a strong inverse correlation with mean blood pressure after dialysis (r=0.608, P=0.0001). In the selected participants who had equal range of mean blood pressure before dialysis, mean plasma NO3- concentrations were greater in subjects with severe hypotension during dialysis (180 +/- 14 micromol L-1) than in those with mild hypotension (99 +/- 11 micromol L-1) or without hypotension (53 +/- 12 micromol L-1); plasma NO3- concentrations before dialysis were inversely correlated with changes in mean blood pressure during dialysis and mean blood pressure after dialysis. Results indicate that enhanced NO production may be involved in acute hypotension during dialysis, and suggest the possible involvement of NO in the pathogenesis of chronic hypotension associated with maintenance haemodialysis.

Adult↗
PubMed2000

Expression of T-cell-associated antigens in B-cell non-Hodgkin's lymphoma.

We performed the immunophenotyping of 101 patients with B-cell non-Hodgkin's lymphoma (B-NHL) using two-colour flow cytometry (FCM) and found that lymphoma cells coexpressed at least one kind of T-cell-associated antigen (T-Ag; CD2, CD5, CD7) in 25 patients (24. 8%). Among these three T-Ags, CD5 was the most frequently expressed, in 21 patients (20.8%), followed by CD7, expressed in five patients (5.0%), and CD2, which was expressed in two patients (2.0%). Two kinds of T-Ag were simultaneusly expressed in three patients (CD2/CD5, CD2/CD7, and CD5/CD7, each expressed in one patient). Concerning the expression pattern of T-Ag, there were no significant differences between lymph nodes and extranodal organs in the three patients with T-Ag-positive B-NHL (T-Ag(+) B-NHL) who were analysed. When comparing the clinical features between T-Ag(+) B-NHL and T-Ag-negative B-NHL (T-Ag(-) B-NHL), extranodal involvement and higher International Prognostic Index (H and H.I.) were significantly frequent in the former subgroup (P = 0.0119 and P = 0. 0302 respectively).

Adolescent↗
PubMed2000

Ginkgo biloba extract attenuates the development of hypertension in deoxycorticosterone acetate-salt hypertensive rats.

1. We examined the effects of Ginkgo biloba extract (GBE) on the development of hypertension, platelet activation and renal dysfunction in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Both DOCA-salt hypertensive rats and normotensive rats were fed a 2% GBE diet for 20 days. Blood pressure (BP) was measured by two methods, namely by the tail-cuff and telemetry methods. 2. Development of hypertension was attenuated in rats fed a 2% GBE diet. In addition, an increase in heart weight, an indicator of sustained high BP, was inhibited significantly by feeding of the GBE diet. 3. Decreases in 5-hydroxytryptamine content in platelets, a marker of platelet activation in vivo associated with hypertension, were also prevented by feeding of the GBE diet. Ginkgo biloba extract itself did not inhibit ADP- and collagen-induced platelet aggregation examined in vitro. Feeding of the GBE diet tended to inhibit increases in plasma urea nitrogen due to hypertension. 4. The telemetry study demonstrated that BP and heart rate (HR) showed a clear circadian rhythm and the antihypertensive effect of GBE was prominent in the daytime, a resting period for rats. This anti-hypertensive effect of GBE was not detected in normotensive rats. In contrast, the inhibitory effect of GBE on HR was independent of time and was observed in both normotensive and hypertensive rats. 5. These results indicate that GBE has an anti-hypertensive and bradycardiac action, which are time dependent and independent, respectively. Thus, it appears that the chronopharmacological action of GBE may be ascribed not to pharmacokinetic factors, but rather to a circadian susceptibility rhythm to GBE in DOCA-salt hypertensive rats.

Animals↗