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Biomedical subjects

T Meguro

Publications and source records attributed to T Meguro.

At least 55 records · Page 3Linked to original sources
PubMed1999

Influence of age on ambulatory electrocardiogram-derived heart rate variability.

OBJECTIVE: To evaluate the quantitative change in heart rate variability with age by using 24 h Holter ambulatory monitoring of electrocardiogram and to set the lower limit of heart rate variability depending on age. PARTICIPANTS: Eighty healthy subjects without any medication (male to female ratio 40:40, 45.6 +/- 14.1 years of age, range 16 to 68 years). METHODS: Holter monitoring was performed, and frequency and time domain heart rate variability was obtained. RESULTS: A significant inverse relationship was found between age and heart rate variability, especially in the frequency domain, and, in the time domain analysis, in the root mean square of the difference in the RR intervals of sinus rhythm (NN) between successive beats and in the portion of NN cycles greater than 50 ms apart. Except for the standard deviation of the mean of RR intervals taken every 5 mins and averaged over 24 h and the ratio of low frequency high frequency power spectra, all parameters decreased to a certain age and did not change thereafter, and the rate of decrease differed among the parameters of heart rate variability. Because age had a strong influence on heart rate variability, the lower limit of heart rate variability for a certain age was determined by using the polynomial curve fitting of the moving average minus 2 SD of 10 consecutive subjects. By using these equations, it could be determined whether heart rate variability was normal or abnormal depending on age.

Adult↗
PubMed1999

[Nedaplatin and etoposide combination chemotherapy in a patient with small cell carcinoma undergoing hemodialysis].

A 61-year-old man with chronic renal failure caused by polycystic kidney disease requiring hemodialysis three times weekly developed small cell carcinoma of the lung. The patient received combination chemotherapy with nedaplatin (50 mg) and etoposide (50 mg). Blood levels were monitored, showing that nedaplatin was more dialyzable than cisplatin. The patient achieved a complete response. These results suggest that nedaplatin-etoposide combination chemotherapy may be safer than cisplatin-containing regimen for patients with chronic renal failure hemodialysis and that a satisfactory response can be expected.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1998

A specific T-cell subset with CD4+/CD38- markers derived from HIV-1 carriers induces apoptosis in healthy donor-derived T-lymphocytes.

Apoptosis is an important mechanism of human immunodeficiency virus type 1 (HIV-1)-induced T-cell depletion. Our recent findings revealed mitogenic stimulation-dependent apoptosis induction in healthy donor-derived peripheral blood T-lymphocytes after adsorption with defective HIV-1 particles through acquirement by a subset of CD4+/CD38- cells of specific killer function. Based on these in vitro observations, we have extended the significance of this killing activity of CD4+/CD38- cells directly derived from HIV-1 carriers. The CD4+/CD38- cells from HIV-1-positive individuals showed significantly higher cell-killing activities than those from HIV-1-negative donors by co-culture with allogeneic resting T-cells after mitogenic stimulation. Furthermore, most of the samples induced apoptosis in a Fas-dependent manner. Thus, it is suggested that HIV-1 infection-related apoptosis is triggered by inappropriate activation of a certain resting T-cell subset, presumably due to adsorption with HIV-1 particles.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Computational observation of an ion permeation through a channel protein.

The ion permeation process, driven by a membrane potential through an outer membrane protein, OmpF porin of Escherichia coli, was simulated by molecular dynamics. A Na+ ion, initially placed in the solvent region at the outer side of the porin channel, moved along the electric field passing through the porin channel in a 1.3 nsec simulation; the permeation rate was consistent with the experimentally estimated channel activity (10(8)-10(9)/sec). It this simulation, it was indicated that the ion permeation through the porin channel proceeds by a "push-out" mechanism, and that Asp113 is an important residue for the channel activity.

Bacterial Proteins↗
PubMed1998

Analysis of clinical AIDS-free interval after CD4+ cell counts fall below 200 x 10(6) L-1 in Japanese haemophiliacs infected with HIV-1.

We analysed the time from the date CD4+ cell counts fell below 200 x 10(6) L-1, defined as ti, to the onset of clinical AIDS, according to the 1987 Centers for Disease Control and Prevention case definition, in 129 Japanese haemophilia patients infected with HIV-1. The cumulative onset of clinical AIDS was analysed by the Kaplan-Meier method and proportional hazard model. Incorporated covariates were age of each patient at time ti, as well as CD4+ and CD8+ cell counts, serum levels of IgG, IgA, IgM, GOT and GPT at ti. The time of antiretroviral treatment initiation was also considered. The 50% AIDS-free interval after ti was 3.00 years (95% confidence interval (CI), range 0.49-5.51) and 1.71 years (95% CI, range 0.66-2.76) for the patients at CDC stage II and stage III, respectively (significantly different, P = 0.0013). Among the patients at CDC stage II at ti, higher levels of IgA were tightly associated with a shorter period from ti to onset of clinical AIDS (P < 0.0001), and relative hazard was 1.35 (95% CI, 1.11-1.64) with increase of IgA level by 1.0 g L-1. Thus there is a broad distribution in the time to onset of clinical AIDS in Japanese haemophiliacs even after CD4+ cell counts fall below 200 x 10(6) L-1. This should be taken into consideration in deciding upon the therapy and care of HIV-1 infected people.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Lack of desensitization and enhanced efficiency of calcium channel promoter in conscious dogs with heart failure.

The goal of this study was to compare responses to a calcium promoter, BAY y 5959, and dobutamine (Dob) in heart failure (HF). Dogs (n = 9) were chronically instrumented and studied in the conscious state before and after pacing-induced HF. In the control state, BAY y 5959 (20 microgram. kg-1. min-1) increased the first derivative of left ventricular (LV) pressure (dP/dt) by 83 +/- 8% and mean arterial pressure (MAP) by 8 +/- 2% and decreased heart rate (HR) by 30 +/- 3%. With Dob (10 microgram. kg-1. min-1) LV dP/dt rose similarly (+80 +/- 6%), but HR also rose (+25 +/- 4%) (P < 0.05 vs. BAY y 5959). After HF developed, BAY y 5959 still increased LV dP/dt by 108 +/- 8% and MAP by 21 +/- 2% and decreased HR by 28 +/- 4%, whereas Dob increased LV dP/dt by only 50 +/- 7% (P < 0.05 vs. BAY y 5959) and MAP by 7 +/- 3%, and HR did not change (+3 +/- 3%) (P < 0.05 vs. BAY y 5959). In HF, cardiac work increased more (P < 0. 05) with BAY y 5959 (+105 +/- 13%) compared with Dob (+47 +/- 11%), yet myocardial oxygen consumption increased similarly with the two drugs. Accordingly, mechanical efficiency increased more (P < 0.05) with BAY y 5959 (+73 +/- 14%) than with Dob (+17 +/- 12%). These data indicate that 1) increases in contractility mediated directly by Ca2+ are relatively resistant to desensitization in HF; and 2) the calcium-channel promoter can produce increases in myocardial contractility and cardiac work similar to those of Dob at a significantly lower oxygen cost, thereby enhancing mechanical efficiency in HF.

Animals↗
PubMed1998

Application of mechanical restitution: variation of inotropic effects of vagal stimulation or verapamil administration during irregular cardiac rhythm.

The effects of verapamil administration or vagal stimulation on the mechanical restitution curve (MRC) were studied in order to better understand the modulation of left ventricular (LV) function by interventions that lower the ventricular rate of atrial fibrillation. The MRC and the postextrasystolic MRC were obtained in 11 dogs using peak single beat elastance (Emax). The MRC was fitted by a monoexponential curve. Vagal stimulation or verapamil administration decreased the peak of the MRC and right-shifted the MRC. The postextrasystolic MRC was located upward compared with the control MRC, and was shifted downward by vagal stimulation or verapamil administration. If interventions having a negative inotropic effect effectively slow a rapid heart rate, the net effect of the ventricular contractile state may not always be negative. It was concluded that the MRC is useful in understanding LV contractility during irregular rhythm, especially when assessing the net effect of the negative dromotropic and inotropic action of antiarrhythmic drugs.

Animals↗
PubMed1997

Correlation of titer of antibody to principal neutralizing domain of HIVMN strain with disease progression in Japanese hemophiliacs seropositive for HIV type 1.

With the use of the principal neutralizing determinant (PND) peptide-based ELISA to measure anti-PND antibodies that specifically bound synthetic peptides derived from HIVIIIB, HIVMN, HIVRF, HIVSC, HIVWJM-2, HIVAf1l.con, or HIVAf2.con, type-specific antibodies to the HIVMN peptide were studied in 350 serum specimens from Japanese with hemophilia A who had been injected with known unheated factor VIII concentrates until 1985 and had been infected with HIV-1 subtype B. These antibodies were not found in any of the seronegative sera of hemophiliacs, patients with autoimmune diseases, or normal healthy controls. Further, all hemophiliacs rapidly progressing to AIDS and death among the 95 hemophiliacs in a restricted Nara area had antibody titers of less than 20 and their low levels preceded the rapid progression to the disease state. In contrast, slowly progressing hemophiliacs maintained an antibody titer of more than 100 from the initial stages of viral infection and remained asymptomatic. Sequence analysis of the V3 regions of HIV-1 indicated that the hemophiliacs who maintained a high anti-PNDMN antibody level showed a conserved MN sequence. In contrast, the HIV-infected hemophiliacs with nonreactivity in the ELISA showed sequence changes in the neutralizing epitopes of HIVMN. The dynamic of the serum anti-PNDMN antibody titer appear to be a characteristic indicator of the progression of the HIV-infected status in Japanese hemophiliacs seropositive for HIV-1.

Adult↗
PubMed1997

Gallbladder emptying and cholecystokinin and pancreatic polypeptide responses to a liquid meal in patients with diabetes mellitus.

To investigate gallbladder motility and its regulation in patients with diabetes mellitus (DM), we examined the gallbladder response to an intraduodenal test meal by measuring the temporal course of plasma cholecystokinin (CCK) and pancreatic polypeptide (PP) levels. Eighteen patients with type 2 DM and 7 healthy subjects (controls) were enrolled. The gallbladder volume was calculated by the sum-of-cylinders method from ultrasonographic images, and plasma CCK and PP were measured by radioimmunoassays. No significant difference was found in either the gallbladder response or in the CCK response between patients with DM and controls. However, the fasting plasma PP level of patients with DM was more than tenfold higher than that of controls. The integrated PP response (IPPR) of patients with DM to the test meal was 8.3-fold higher than that of controls. When patients with DM were grouped according to whether they had been treated with insulin or not, the fasting plasma PP of patients with DM without insulin treatment was significantly higher than the level in those treated with insulin. These results suggest that overproduction of PP-like immunoreactive substance(s) may occur in patients with DM, but the high plasma PP immunoreactivity does not appear to be related to the fasting gallbladder volume or to gallbladder emptying and filling.

Adult↗
PubMed1997

Long-term follow-up study of patients with unilateral moyamoya disease.

Although a number of cases of unilateral Moyamoya disease have been reported, the natural history of this disease remains unclear. The clinical features of 17 patients initially diagnosed with unilateral Moyamoya disease at our hospital are reported. Age at onset was 3-45 years (mean, 13.5). Of these 12 cases had onset of symptoms in childhood and five had onset in adulthood. Seven were male and 10 were female. An ischemic attack was the initial episode in ten of the 12 pediatric cases, two of the five adult cases presented with intraventricular hemorrhage. Of the 12 pediatric patients six developed contralateral lesions between 4 and 34 months (mean, 20) after the diagnosis of a unilateral lesion. The remaining six pediatric patients and all adult patients did not develop lesions on the normal side. The mean age at onset for patients later developing contralateral lesions was 6.2 years. The pediatric cases remaining unilateral was 7.7 years. The normal hemisphere of three of the pediatric patients has remained unchanged on repeated follow-up angiograms for over 10 years. Young children tended to develop the vascular pathology bilaterally. However, there were some pediatric cases whose normal or atypical sides remained unchanged without development of bilateral lesions.

Adolescent↗
PubMed1997

Long-term results of surgically treated moyamoya disease.

Various surgical procedures have been tried for patients with Moyamoya disease. The most effective treatment, however, is still controversial. We retrospectively evaluated the long-term results of 71 patients (26 men and 45 women) with Moyamoya disease surgically treated in our institute. They consisted of 56 pediatric patients (younger than 15 years) and 15 adult patients. Symptoms in all patients were due to cerebral ischemia. We did 123 operations on 119 hemispheres: 18 superficial temporal artery--middle cerebral artery (STA-MCA) anastomoses, six STA-MCA anastomoses with indirect bypass (IB), 41 encephalo-duro-arterio-synangiosis (EDAS), 29 encephalo-duro-arterio-myo-synangiosis (EDAMS) and 29 ribbon EDAMS. Average follow-up periods for each procedure were: 7 years for STA-MCA anastomosis, 6.2 years for STA-MCA anastomosis with indirect bypass, 11 years for EDAS, 5.6 years for EDAMS and 2.6 years for ribbon EDAMS, respectively. The results of each procedure were satisfactory because the preoperative transient ischemic attacks disappeared. Analysis of follow-up angiograms shows excellent filling of the ACA and MCA territory in the patients undergoing ribbon EDAMS. However, long-term follow-up study shows that about 10% of the patients had severe difficulty in social or school life because of intellectual impairment.

Anastomosis, Surgical↗
PubMed1997

Interferon therapy for Japanese hemophiliacs with chronic hepatitis C.

Eight Japanese hemophiliacs with chronic hepatitis C (CHC) received interferon (IFN) therapy and four of them (50%) responded completely. Non-responders included 3 double-infected patients: 1 with hepatitis B virus (HBV) and 2 with human immunodeficiency virus-1 (HIV-1). In one of the patients with HIV-1 double infection, the absolute number of CD4+ lymphocytes decreased during IFN therapy. These findings suggest that hemophiliac patients with CHC can respond well to IFN therapy, but in patients who are double-infected with HBV and HIV-1, the indication of IFN therapy should be considered seriously.

Adolescent↗
PubMed1997

Sinus pericranii associated with a cerebellar venous angioma--case report.

A 64-year-old male presented with sinus pericranii associated with a venous angioma draining through a large venous lake. Increased venous pressure and flow in the dural venous lake in contact with the venous sinus may have developed the sinus pericranii. Three-dimensional computed tomography was very useful in determining the site of the transcranial venous anastomotic channels, and magnetic resonance imaging was also very useful in detecting the intracranial vascular anomalies.

Cerebral Veins↗
PubMed1997

[Two cases of remitting seronegative symmetrical synovitis with pitting edema].

We report 2 elderly patients who present with a relatively acute onset of a severe symmetrical synovitis affecting the flexor digitorum tendon sheaths and wrist joints with pitting edema of the dorsum of both hands. These patients were seronegative for rheumatoid factor and responded to treatment with low dose predonisone (10 mg daily) without relapse. These presenting features were closely linked with the RS3PE syndrome originally described by McCarty.

Aged↗
PubMed1996

Infection with hepatitis GB virus C in patients on maintenance hemodialysis.

BACKGROUND: A recently discovered non-A-E hepatitis virus has been designated hepatitis GB virus C (HGBV-C), but little is known about its mode of transmission and its clinical manifestations. We studied 519 patients on maintenance hemodialysis to determine whether they were infected with HGBV-C. METHODS: HGBV-C RNA was identified in serum by a reverse-transcription-polymerase-chain-reaction assay with nested primers deduced from a non-structural region. A nucleotide sequence of 100 bp in the nonstructural region was determined on HGBV-C clones. RESULTS: HGBV-C RNA was detected on 3.1 percent of the patients on hemodialysis (16 of 519), as compared with 0.9 percent of healthy blood donors (4 of 448, P<0.03). None of the 16 patients had evidence of active liver disease, although 7 were also infected with hepatitis C virus. Eight patients with HGBV-C infection were followed for 7 to 16 years. In two patients the virus was present at the start of hemodialysis. One had a history of transfusion, and HGBV-C persisted over a period of 16 years; the other became free of HGBV-C after 10 years. In five patients, HGBV-C RNA was first detected 3 to 20 weeks after blood transfusion and persisted for up to 13 years. One patient with no history of transfusion was infected with an HGBV-C variant with the same sequence as in two of the patients with post-transfusion HGBV-C infections. CONCLUSIONS: Patients on maintenance hemodialysis are at increased risk for HGBV-C infection. This virus produces persistent infections, which may be transmitted by transfusions but may also be transmitted by other means.

Adult↗
PubMed1996

Effects of ethanol on meal-stimulated secretion of pancreatic polypeptide and cholecystokinin: comparison of healthy volunteers, heavy drinkers, and patients with chronic pancreatitis.

Tiscornia and Dreiling (Physiopathogenic Hypothesis of Alcoholic Pancreatitis: Supranormal Ecbolic Stimulation of the "Pancreon" Units Secondary to the Loss of the Negative Component of Pancreas Innervation. Pancreas 1987;2:604-612.) proposed that hypertonicity of intrapancreatic cholinergic neurons provoked by chronic alcoholism may contribute to the pathogenesis of chronic pancreatitis (CP). In the present study, the validity of this hypothesis was investigated in humans by studying the effects of atropine, cisapride, and ethanol on the meal-stimulated secretion of pancreatic polypeptide (PP) and cholecystokinin (CCK) in healthy volunteers, heavy drinkers, and CP patients. In healthy volunteers, the early phase PP response (0-40 min) to a test meal was completely blocked by atropine, whereas it was augmented by cisapride, an enhancer of acetylcholine release from cholinergic nerves. The early phase PP response to a test meal was inhibited by ethanol in healthy volunteers, whereas, in heavy drinkers, the response was augmented and the inhibition by ethanol was abrogated. In CP patients, ethanol tended to enhance the early phase PP response. Ethanol did not affect the early phase CCK response to a test meal in any group, but it significantly enhanced the late phase CCK response (40-120 min) in CP patients. These results suggest that: (i) oral ethanol may inhibit the postprandial activation of the cholinergic neural pathway to the pancreas in healthy subjects, (ii) in heavy drinkers, postprandial cholinergic tone may be augmented and become resistant to the inhibition by ethanol, and (iii) the ethanol-induced increase in the postprandial CCK response in CP patients may play some role in the pathophysiology of this disease.

Adult↗
PubMed1996

Suprasellar granular cell tumor.

A 75-year-old female presented with a suprasellar granular cell tumor. Computed tomography (CT) revealed a high dense suprasellar mass with strong postcontrast enhancement. Magnetic resonance imaging showed a round suprasellar mass, which was hyperintense on the T1-weighted images with nonhomogeneous enhancement after the administration of gadolinium-diethylenetriaminepenta- acetic acid, and hypointense on the T2-weighted images. Cerebral angiography demonstrated no abnormal findings. The tumor was partially removed via a right frontotemporal craniotomy. The histological diagnosis was suprasellar granular cell tumor. Her postoperative course was uneventful other than mild and transient diabetes insipidus. She has remained asymptomatic without CT evidence of tumor regrowth for 20 months after the surgery. Immunohistochemical studies showed positive reaction for S-100 protein in the tumor cell nuclei, but no reaction for glial fibrillary acidic protein, neurofilament protein, Leu-7, oxytocin, beta-endorphin, adrenocorticotropic hormone, and vimentin. This case provides additional evidence for the astrocytic origin of suprasellar granular cell tumor.

Aged↗