Search PubMed⌕ Search

Biomedical subjects

M Nasu

Publications and source records attributed to M Nasu.

At least 73 records · Page 4Linked to original sources
PubMed1999

Relation between negative U waves in precordial leads on the admission electrocardiogram and time course of left ventricular wall motion in anterior wall acute myocardial infarction.

This study indicates that patients with anterior wall acute myocardial infarction showing negative U waves in the precordial leads on the admission electrocardiogram have greater improvement in left ventricular wall motion in the infarct region between 1 and 6 months after acute myocardial infarction. This suggests that these patients have a larger amount of stunned myocardium in the infarct region.

Aged↗
PubMed1999

Relation of QT dispersion to infarct size and left ventricular wall motion in anterior wall acute myocardial infarction.

Previous studies have shown that QT dispersion increases during acute myocardial infarction (AMI). However, the relation of QT dispersion to infarct size and left ventricular (LV) function in AMI has not yet been fully clarified. Accordingly, this study was conducted to elucidate this relation at 1 month after anterior wall AMI. We examined 94 patients with first anterior wall AMI (< or = 6 hours) who underwent coronary arteriography at admission, 1 month, and 6 months after AMI, and left ventriculography at 1 and 6 months after AMI. Mean QT dispersion on the chronic phase (about 1 month after AMI) electrocardiogram was 79 +/- 33 ms. There were no significant correlations between QT dispersion and peak creatine phosphokinase levels, LV ejection fraction, and regional wall motion in the infarct region at 1 month after AMI (r = 0.06, p = 0.57; r = 0.11, p = 0.29; r = -0.05, p = 0.63, respectively). In conclusion, the findings of this study suggest that QT dispersion on the resting electrocardiogram at 1 month after anterior wall AMI is unrelated to infarct size estimated by the peak creatine phosphokinase level and the degree of LV dysfunction.

Aged↗
PubMed1999

Reactive oxygen species production of neutrophils in patients with acute promyelocytic leukemia during treatment with all-trans retinoic acid.

We measured N-formyl-methionyl-leucyl-phenylalanine-induced reactive oxygen species production by neutrophils from three patients with acute promyelocytic leukemia during treatment with all-trans retinoic acid using a luminol-enhanced chemiluminescence assay. The maximum level of reactive oxygen species production during all-trans retinoic acid treatment was 58.8 +/- 2.3 x 10(4) (mean +/- SEM) counted photons per seconds (cps), which was significantly higher (p<0.0001) than that of neutrophils from health volunteers (13.3 +/- 2.3 x 10(4) cps).

Antineoplastic Agents↗
PubMed1999

Spatiotemporal representation of binaural difference in time and intensity of sound in the guinea pig auditory cortex.

Neural activity of the auditory cortex (AC) in response to a change of interaural intensity difference (IID) and interaural time difference (ITD) of sound stimuli was observed by optical recording with a 12 x 12 photodiode array and the voltage-sensitive dye, RH795. Guinea pigs (280-450 g) were anesthetized with sodium pentobarbital (30 mg/kg) and supplemental doses of neuroleptic solutions. When both ears were stimulated dichotically by tone bursts (14 kHz, 75 dB SPL), excitatory optical signals appeared in both anterior (A) and dorsocaudal (DC) fields of AC. An increase of intensity of ipsilateral stimulation from 65 to 95 dB SPL caused a decrease of neural activity of isofrequency bands in both fields. An increase of ipsilateral leads from -2.5 to 10 ms resulted in a gradual decrease of the amplitude of the excitatory responses. A strong inhibition was observed in field DC and the ventral portion of field A. These results show the different spatiotemporal representation of IID and ITD sensitivities in AC. However, the ipsilateral lead inducing a large inhibition was much longer than the time difference (80 micros) calculated from the interaural distance of the guinea pig. This indicates that the longer binaural inhibition observed in AC would have a different functional significance from that of the neural system of ITD detection in the guinea pig.

Acoustic Stimulation↗
PubMed1999

Improved efficacy with nonsimultaneous administration of netilmicin and minocycline against methicillin-resistant Staphylococcus aureus in in vitro and in vivo models.

The effect of combined administration of netilmicin and minocycline against methicillin-resistant Staphylococcus aureus (MRSA) was investigated by using in vitro and in vivo models. Thirty one isolates of MRSA were tested for sensitivity to netilmicin, minocycline, and combination of both by the chequer board method. We used then a dynamic in vitro system, which simulates in vivo serum kinetics, to assess the effect of various combination regimens of these antibiotics against an MRSA isolate with a fractional inhibitory concentration index of 0.25. The following dose regimens were compared: netilmicin given alone; minocycline given alone; both antibiotics given simultaneously; netilmicin followed by minocycline at 2 h; or minocycline followed by netilmicin at 2 h. Netilmicin showed a stronger activity than minocycline. On the other hand, their combination was synergistic against 19% of isolates and additive against 77% of isolates. Against one isolate only, it was indifferent, and no antagonism was observed. In the auto-simulation system, the combination of antibiotics was generally more effective than single drugs, with the regimen netilmicin followed by minocycline at 2 h showing the highest antibacterial effect. In the mouse model of pulmonary infection, the bacterial counts and histopathological findings of the lungs improved by treatment with this regimen. This regimen led also to a significantly high survival rate of mice with systemic infection compared to the other treatment regimens. Therefore, it was concluded that administration of netilmicin followed by minocycline at 2 h may be an effective combination against MRSA infection.

Animals↗
PubMed1999

Effect of recombinant human growth hormone in elderly osteoporotic women.

OBJECTIVE: Bone mineral density and growth hormone (GH) secretion rate both decline during normal human ageing. We evaluated the effects of recombinant human GH on markers of body composition and bone turnover in an open study in 8 elderly osteoporotic women aged 68-75 years (mean age 71 years). DESIGN: Subjects were treated with GH as a single daily subcutaneous injection (0.125 IU/kg/week for the first 4 weeks and subsequently 0.25 IU/kg/week) for 48 weeks. RESULTS: GH treatment caused a rapid (within 2 weeks) increase in serum levels of IGF-I and IGF-binding protein-3 (IGFBP-3) which was sustained throughout the study. Markers of bone formation and resorption were both gradually increased up to 24 weeks of GH treatment. The bone formation markers, osteocalcin (OC) and bone alkaline phosphatase, remained high during GH treatment, while the bone resorption marker, deoxypyridinoline (D-Pyr), tended to return to baseline levels after 24 weeks of GH therapy. GH treatment for 48 weeks caused a significant increase in hand grip and a decrease in waist/hip ratio. The mean percentage changes in bone mineral density (BMD) of mid-radius and lumbar spine were + 2.1% and + 1.2%, respectively, although they were not statistically significant. GH treatment was well tolerated and no major side-effects except mild oedema and joint pain were found. Since GH treatment produced durable increases in bone formation markers, BMD continued to be monitored after discontinuation of GH treatment for another 48 weeks, during which significant increases in radial and lumbar BMD (8.1 +/- 2.1 and 3.8 +/- 1.4% above pre- treatment values, respectively) were recorded. CONCLUSION: These results indicate that GH attenuates the decrease in muscle strength and bone mass as well as the gain of abdominal fat with ageing in elderly women. The present data provide useful information about the application of GH treatment in elderly women.

Aged↗
PubMed1999

Abundance and distribution of bacteria carrying sltII gene in natural river water.

Direct in situ PCR with HNPP/Fast Red TR was used to enumerate bacteria carrying the sltII gene in river water. By direct in situ PCR with a sltII-specific EVS primer, 10(2)-10(5) cells ml-1 of bacteria carrying the sltII gene were detected from all sampling sites, except the site nearest to the source of the river, while 10(2)-10(4) cells ml-1 of Escherichia coli O157:H7 were detected using a direct fluorescent antibody staining method. These results indicate that such bacteria are commonly distributed in natural river water. Direct in situ PCR with HNPP/Fast Red TR is a useful tool for detecting cells carrying specific genes, such as verotoxin-producing bacteria in natural environments.

Bacterial Toxins↗
PubMed1999

Rapid enumeration of physiologically active bacteria in purified water used in the pharmaceutical manufacturing process.

Physiologically active bacteria in purified water used in the manufacturing process of pharmaceutical products were enumerated in situ. Bacteria with growth potential were enumerated using the micro-colony technique and direct viable counting (DVC), followed by 24 h of incubation in 100-fold diluted SCDB (Soybean Casein Digest Broth) at 30 degrees C. Respiring and esterase-active bacteria were detected by fluorescent staining with 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and 6-carboxyfluorescein diacetate (6CFDA), respectively. A large number of bacteria in purified water retained physiological activity, while most could not form colonies on conventional media. The techniques applied in this study enabled bacteria to be counted within 24 h so results could be available within one working day. These rapid and convenient techniques should be useful for the systematic monitoring of bacteria in water used for pharmaceutical manufacturing.

Bacteriological Techniques↗
PubMed1999

Analysis of p53 gene mutations in Helicobacter pylori-associated gastritis mucosa in endoscopic biopsy specimens.

BACKGROUND: No previous report has shown the relationship between Helicobacter pylori infection and a direct sequence analysis of p53 gene mutation in a biopsy sample of human gastric mucosa. METHODS: A total of 60 endoscopic biopsies samples (21 patients with H. pylori-positive gastritis and 9 patients with H. pylori-negative gastritis), including antral mucosa and corpus mucosa, were used in this study. Direct DNA sequencing of exons 5, 6, 7, and 8 of the p53 gene was performed by the dyedeoxy terminator method. RESULTS: Mutations in the p53 gene were identified in non-hot spot codons in exon 7 and 8 in 11 of 21 samples (52.4%) from H. pylori-positive gastritis patients. There was no mutation in H. pylori-negative gastritis patients. CONCLUSIONS: This finding shows that H. pylori infection can induce p53 point mutations and appears to be involved in the pathway leading to dysplasia or carcinoma.

Adult↗
PubMed1999

Effect of Helicobacter pylori infection on the N-methyl-N'-nitro-N-nitrosoguanidine-induced gastric carcinogenesis in mongolian gerbils.

The effect of Helicobacter pylori infection on N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric cancer was studied using a Mongolian gerbil model. Five-week-old male Mongolian gerbils were divided into four groups of 25-30 animals each and challenged for 20 weeks with H.pylori, MNNG, a combination of H.pylori and MNNG, or neither of them. Four to 20 animals from each group were killed at 16, 24 and 52 weeks after H.pylori inoculation, and histopathological changes in their stomachs were examined. A well-differentiated adenocarcinoma was first observed 24 weeks after inoculation in the combination group. At 52 weeks, only six of 15 animals were colonized with H.pylori persistently, and four of them showed well-differentiated adenocarcinomas; on the other hand, neither of the animals with disappearance of H.pylori from the combination group showed adenocarcinoma. At the same observation time, three of 17 animals from MNNG group showed poorly differentiated adenocarcinomas. The incidence of gastric carcinoma in the combination group was significantly higher than that in the MNNG group (P < 0.05). However, no tumors were seen in the control and H.pylori groups. The present findings demonstrate that H.pylori infection enhances the carcinogenic action of MNNG.

Adenocarcinoma↗
PubMed1999

Effect of bepridil on intracellular calcium concentration and contraction in cultured rat ventricular myocytes.

We studied the effects of a new antiarrhythmic and antianginal agent, bepridil, on the intracellular calcium transient and contraction of cultured neonatal rat ventricular cells, and compared the effects with those caused by an authentic Ca2+ -entry blocker, D600 (methoxyverapamil). The Ca2+ transient was measured by using dual-wavelength microfluorometry of fura-2. The contraction was measured as a shortening of cell aggregates with the use of a video image-analyzing system. Both bepridil (1-30 microM) and D600 (1-30 microM) decreased the peak systolic amplitude of the Ca2+ transient in a concentration- and frequency-dependent manner. Bepridil, but not D600, significantly shortened the half-decay time of the Ca2+ transient and prolonged the time course of the contraction. D600 decreased the contraction in parallel with the decrease in the peak Ca2+ transient, whereas bepridil exerted no significant effect on the contraction. Bepridil (10 microM) induced a leftward shift (to lower amplitude of peak systolic Ca2+ transient) of the relation between the magnitude of contraction and the peak systolic Ca2+ transient, which was obtained by changing external Ca2+ concentration. In contrast, D600 (10 microM) did not affect the relation. The results suggest that the negative inotropic effect of bepridil (caused by its Ca2+ channel-blocking effect) is offset by its simultaneous increase in the sensitivity of contractile protein(s) to intracellular Ca2+, which may be a unique characteristic of this antiarrhythmic agent in a clinical setting.

Animals↗
PubMed1999

Clindamycin suppresses endotoxin released by ceftazidime-treated Escherichia coli O55:B5 and subsequent production of tumor necrosis factor alpha and interleukin-1 beta.

Treatment of septicemia caused by Escherichia coli with ceftazidime (CAZ) may be associated with the development of septic shock due to the release of bacterial lipopolysaccharide. We examined the suppressive effect of clindamycin (CLDM) on CAZ-induced release of endotoxin by cultured E. coli and the subsequent production of inflammatory cytokines (tumor necrosis factor alpha [TNF-alpha] and interleukin-1 beta [IL-1 beta]). E. coli ATCC 12014 was incubated in inactivated horse serum with or without CLDM for 1, 4, or 18 h, followed by the addition of CAZ and collection of the culture supernatant at 0, 1, and 2 h. The concentration of endotoxin in each sample was measured by a chromogenic Limulus test. Another portion of the culture supernatant was added to THP-1 cell culture and incubated for 4 h, and the concentrations of TNF-alpha and IL-1 beta in the supernatant were measured by an enzyme-linked immunosorbent assay. In the control group (no CLDM), CAZ administration resulted in significant increases in endotoxin, TNF-alpha, and IL-1 beta concentrations. Pretreatment of E. coli with CLDM for 4 or 18 h before the addition of CAZ significantly suppressed the concentrations of endotoxin, TNF-alpha, and IL-1 beta in a time-dependent manner. In addition, CAZ treatment transformed E. coli from rodshaped bacteria to filament-like structures, as determined by electron microscopy, while pretreatment with CLDM prevented these morphological changes. Our in vitro studies showed that CAZ-induced release of large quantities of endotoxin by E. coli could be suppressed by prior administration of CLDM.

Anti-Bacterial Agents↗
PubMed1999

Local secretory immunoglobulin A and postimmunization gastritis correlate with protection against Helicobacter pylori infection after oral vaccination of mice.

C57BL/6 mice were orally immunized with five weekly doses of 2 mg, 200 microgram, or 2 microgram of Helicobacter pylori (Sydney strain) whole-cell sonicate combined with cholera toxin. One week after the last vaccination, mice were challenged with 5 x 10(7) CFU of live H. pylori three times at 2-day intervals. At 6 or 18 weeks after the challenge, mice were sacrificed and bacterial cultures and histological studies of the stomach were performed. Vaccination with 2 mg/session or 200 microgram/session inhibited H. pylori colonization by 90 and 100%, respectively. These mice were considered protected. Lower levels of H. pylori-specific immunoglobulin A (IgA) were detected in fecal and saliva samples before challenge. However, a significant increase in IgA secretion in mucosal tissue and a higher labeling index for IgA-positive lumina of pyloric glands were noted in these mice in response to challenge and in a vaccine dose-dependent manner. In protected mice, however, severe gastritis characterized by marked infiltration of inflammation mononuclear cells was noted at 6 weeks after challenge, compared with the gastritis seen in unprotected mice or nonvaccinated, ordinarily infected mice. Marked expression of gamma interferon mRNA was detected in the stomach of all protected mice, and 50% of these mice expressed interleukin 4 (IL-4) or IL-5 mRNA. Our findings suggest that local secretory IgA antibody and severe postimmunization gastritis correlate well with protection of mice against H. pylori infection.

Administration, Oral↗
PubMed1999

PCR detection of DNA specific for Trichosporon species in serum of patients with disseminated trichosporonosis.

Deep-seated trichosporonosis is a lethal opportunistic infection that disseminates rapidly and widely in immunocompromised patients, and early diagnosis is crucial for the treatment of this infection. We developed a novel nested-PCR assay that detects DNA specific for clinically important strains of Trichosporon in serum samples from patients with disseminated trichosporonosis. In this assay, two sets of oligonucleotide primers were derived from the sequence of 26S rRNA genes of Trichosporon asahii. The specific fragment was amplified from T. asahii and T. mucoides, but not from other microorganisms, including some other basidiomycetous fungi (Cryptococcus, Malassezia, Rhodotorula, and Sporobolomyces). Target DNA was detected by the nested PCR with as little as 5 fg of the extracted DNA of T. asahii. In a study using 11 clinical samples, the specific fragment was detected by the nested PCR in 64% (7 of 11) of sera from patients with histologically diagnosed disseminated trichosporonosis, while glucuronoxylomannan antigen was detected in only 54% (6 of 11) of the samples. Our new nested-PCR assay using serum samples can be performed repeatedly throughout the course of the disease. In addition, not only can it be used for early diagnosis of trichosporonosis, but it may also be beneficial for monitoring its progress or response to therapy.

Aged↗
PubMed1999

Angiographic and clinical significance of 'transient' ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction.

This study aimed to clarify the significance of ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction (AMI) with ST-segment elevation. A total of 196 patients with their first anterior wall AMI (< or =6h) were divided into 2 groups according to the presence (group A, n=39) or absence (group B, n=157) of ST-segment depression > or =0.1 mV in V5 and/or V6 on the admission electrocardiogram. Patients with electrocardiographic confounding factors were excluded. No patients had persistent ST-segment depression in the lateral chest leads. Emergency coronary angiography revealed that group A had higher incidences of occlusion of the left anterior descending coronary artery (LAD) proximal to its first septal branch (77% vs 51%, p<0.01) and good collateral circulation than group B (46% vs 25%, p<0.05). Peak creatine kinase levels were significantly lower in group A than in group B (2060+/-1099 vs 2873+/-2077 IU/L, p<0.01). Left ventricular ejection fraction in the chronic phase was significantly greater in group A than in group B. Regional wall motion in the infarct region in the chronic phase was better in group A than in group B. These results indicate that patients with 'transient' ST-segment depression in the lateral chest leads in anterior wall AMI had a relatively smaller infarct size, despite their higher incidence of occlusion of the LAD proximal to its first septal branch, because of their higher incidence of good collateral circulation.

Aged↗
PubMed1999

Clinical usefulness of the proximal isovelocity surface area method using echocardiography in patients with eccentric aortic regurgitation.

BACKGROUND AND AIM OF THE STUDY: The Doppler color flow mapping techniques of the distal jet are influenced by the eccentricity of aortic regurgitation (AR). The aim of this study was to clarify screening variables for assessing AR severity in patients with an eccentric jet. METHODS: Fifty-four patients with eccentric AR were studied. Values of the radius and effective regurgitant orifice area (EROA) determined by the proximal isovelocity surface area (PISA) method using transthoracic echocardiography (TTE) were compared with measurements by multiplane transesophageal echocardiography (m-TEE), aortic angiography and regurgitant fraction. RESULTS: In patients with eccentric AR, values of PISA radius and EROA by TTE correlated well with values made by m-TEE (r = 0.87, p<0.001 and r = 0.86, p<0.001, respectively), angiographic grade (rs = 0.87, p<0.001 and rs = 0.88, p<0.001, respectively) and regurgitant fraction (r = 0.88, p<0.001 and r = 0.84, p<0.001, respectively). Values of PISA radius > or =0.70 cm and EROA > or =0.25 cm2 were always associated with a regurgitant fraction > or =0.40, while PISA radius <0.70 cm and EROA <0.25 cm2 were always associated with a regurgitant fraction <0.40. CONCLUSIONS: Measurements determined by the PISA method, using either TTE or m-TEE, are reliable for assessing the severity of eccentric AR. PISA radius is easy to obtain and therefore widely applicable in clinical practice as a screening tool for evaluating eccentric AR severity.

Adult↗
PubMed1999

[Epstein-Barr virus associated Richter's syndrome accompanied by interstitial pneumonia].

A 65-year-old man who had an 8-year history of chronic lymphocytic leukemia was admitted to our hospital on February 19, 1998 because of high fever, dry cough, and weight loss. Laboratory data on admission included serum lactate dehydrogenase at 980 IU/l, CRP at 21.8 mg/dl, and soluble interleukin-2 receptor at 7,280 U/ml. The results of serological tests for Epstein-Barr virus (EBV) antibodies were as follows: EBV capsid antigen IgG 1:2560, EBV early antigen IgG 1:640, and EBV nuclear antigens 1:20. Computed tomography revealed diffuse interstitial pneumonia in both lungs, hepatosplenomegaly with multiple nodules, and enlarged intra-abdominal lymph nodes. In addition, Gallium-67 scintigraphy demonstrated abnormal accumulations. Although the patient initially responded well to combination chemotherapy, he eventually deteriorated and died on November 2, 1988, despite salvage chemotherapy. Postmortem needle biopsy specimens from the liver and spleen revealed diffuse proliferation of polymorphic large lymphoma cells. The lymphoma cells were positive for L-26, latent membrane protein 1, and EBV nuclear antigen, but negative for UCHL-1 and CD3, 5, 10, and 30. In situ hybridization procedures disclosed the presence of EBV-encoded small RNA in lymphoma cells. These findings suggested the possibility of association with EBV infection in some cases of Richter's syndrome.

Aged↗