Search PubMed⌕ Search

Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 955 records · Page 53Linked to original sources
PubMed1992

Tsutsugamushi disease in the central part of Japan.

Two cases of tsutsugamushi disease misdiagnosed initially as drug eruption were reported. Clinical symptoms of both cases disappeared dramatically after starting minocycline. Statistical examinations were performed on 29 cases of tsutsugamushi disease, including those observed in Mie Prefecture since 1982. Half of them were seen in the last 2 years. The onset was predominantly recorded in November (59%). Presumptive sites of infection were forests (63%) and fields (21%). No patients were infected along river-banks.

Adult↗
PubMed1992

Palindromic morphea: multiple recurrence of morphea lesions in a case of systemic sclerosis.

We report an unusual scleroderma case. A 45-year-old woman had recurrent morphea lesions over 10 times in 6 years. She had had preceding inactive systemic scleroderma. New morphea lesions developed cyclically on various portions of her body and improved within 2 years. Interestingly, new lesions have developed on once involved skin as well as uninvolved skin. No exacerbation of systemic scleroderma was induced by outbreaks of new morphea lesions. We could not find a similar case in the literature and named it "Palindromic morphea" because of its unique clinical course. D-penicillamine treatment had a limited effect. Minimal oral prednisolone (5 mg/day) completely suppressed the multiple recurrence of the morphea lesions and enhanced improvement of the sclerosis.

Female↗
PubMed1992

Tsutsugamushi disease (scrub typhus).

Two patients with Tsutsugamushi disease (fever) were successfully treated with tetracycline derivatives after typical eschars were found, although one of the patients was initially misdiagnosed as having a drug reaction eruption. Prompt diagnosis and treatment are important because this disease can be associated with considerable morbidity and simple effective treatment is easily available.

Adult↗
PubMed1992

Prevention of perinatal transmission of hepatitis B virus carrier state.

By means of passive and active immunization with hepatitis B immunoglobulin and hepatitis B vaccine, 396 of 407 babies born to hepatitis B antigen-positive carrier mothers, were protected from establishing the hepatitis B virus (HBV) carrier state during a follow-up period of 12 months or longer. Four infants developed the HBV carrier state before the completion of the immunoprophylaxis schedule, and another seven developed the state after the completion of the schedule. Seroconversion of anti-HBc was observed in 26.8% of the successfully protected infants. In Japan a nationwide program to prevent the vertical transmission of HBV with these procedures was established in 1986, and so liver diseases due to HBV are expected to be eliminated in the near future.

Carrier State↗
PubMed1992

Blood flow in a brachial artery compressed externally by a pneumatic cuff.

Blood flow in human brachial arteries, compressed by a pneumatic cuff for blood pressure measurement, is examined using several different noninvasive techniques. From the experimental results it is shown that, when arterial pressure distal to the cuff is always lower than cuff pressure, flow in the artery under the cuff becomes supercritical near the cuff downstream margin and no reflection occurs there and the reflected wave from the peripheral vascular system of the arm does not propagate beyond the cuff downstream margin. Therefore an unsteady transition from supercritical to subcritical flow occurs near the cuff downstream margin. When the peak value of distal arterial pressure exceeds cuff pressure, a reflection occurs near the cuff downstream margin. The reflection becomes stronger corresponding to decrement of the cuff pressure and the whole artery segment under the cuff inflates fully at systole. At diastole, however, the artery segment under the cuff does not collapse completely and, hence, the phenomenon becomes that of pressure wave propagation in a partially collapsed artery segment.

Auscultation↗
PubMed1992

Long-term course and cardiac sympathetic nerve activity in patients with hypertrophic cardiomyopathy.

OBJECTIVE: To investigate the relation between regional myocardial sympathetic nerve activity and the electrocardiographic and cardiac functional changes in hypertrophic cardiomyopathy. DESIGN: A retrospective study to compare the findings of myocardial scintigraphy with iodine-123 metaiodobenzylguanidine (MIBG) and the serial electrocardiographic changes. SETTING: Myocardial scintigraphy was performed with iodine-123 MIBG and thallium-201 and single photon emission computed tomography (SPECT) in the division of nuclear medicine of Kanazawa University Hospital. Both SPECT studies were performed within a week. PATIENTS: 22 patients with hypertrophic cardiomyopathy classified according to their serial electrocardiographic changes--namely, 15 patients with an increase in or the appearance of a negative T wave (group A) and seven patients with a conduction disturbance or a decrease in or disappearance of the negative T wave (group B). The mean follow up period was 45 (range 12-143) months. RESULTS: Group B showed a high rate of decreased activity or defects in MIBG uptake compared with group A (p less than 0.005). The areas of decreased activity or defects corresponded with the hypertrophied portion of the left ventricular wall. Although the early myocardial uptake (MIBG: thallium ratio) was similar in both groups, the mean (SD) MIBG clearance rate was significantly higher (p less than 0.05) in group B (0.25 (0.17)) than in group A (0.10 (0.15)). CONCLUSION: Abnormalities of regional myocardial sympathetic nerve activity may be important in patients with hypertrophic cardiomyopathy and suspected progression of myocardial damage.

3-Iodobenzylguanidine↗
PubMed1992

Enhancement of differentiation of cultured adipogenic cells (TA1) by pertussis toxin.

Differentiation of adipocytes is controlled by a variety of hormones and growth factors. To investigate the possible role of GTP-binding proteins (G proteins) in the process of adipose conversion, we studied the effect of pertussis toxin on differentiation of the fibroblast/adipocyte cell line (TA1). Pertussis toxin potentiated dexamethasone- and indomethacin-induced adipocyte differentiation in a time- and dose-dependent fashion. Addition of dibutyryl cAMP or forskolin inhibited adipose conversion, indicating that an abolishment of inhibitory control of adenylate cyclase is not responsible for the action of pertussis toxin. The B oligomer of the toxin did not mimic the effect of the holotoxin. Pertussis toxin catalyzed ADP-ribosylation of 40,000 molecular mass protein of the membrane fraction was dose-dependently inhibited by the pretreatment of the cells with the toxin. These results indicate the possible involvement of pertussis toxin-sensitive G proteins in adipogenesis.

Adenosine Diphosphate Ribose↗
PubMed1992

Retroviral envelope glycoprotein (gp 70) is not a prerequisite for pathogenesis of primary immunoglobulin A nephropathy in ddY mice.

Deposition of a major retroviral envelope glycoprotein, gp 70, in renal glomeruli of ddY mice, an animal model for primary IgA nephropathy, was examined by immunofluorescence. The positive staining of gp 70 was not observed in glomeruli of our substrain of ddY mice at any ages examined using two different anti-gp 70 antisera and three different staining conditions, whereas deposition of IgA, IgG and IgM was manifest in mice aged over 40 weeks. As a control, NZB x NZW F1 mice from 4 months of age onwards showed severe glomerular deposition of gp 70, in keeping with previous reports. Thus, it appears that gp 70 deposition may not be sine qua non for the pathogenesis of IgA nephropathy of all substrains of ddY mice.

Animals↗
PubMed1992

Endothelin-1 suppression of rat adipocyte precursor cell differentiation in serum-free culture.

The effect of endothelin-1 (ET-1) on differentiation of rat adipocyte precursor cells in serum-free culture and of the adipogenic fibroblast cell line TA1 was studied. ET-1 inhibited differentiation of rat adipocyte precursor cells into adipocytes in a dose-dependent fashion, while the peptide exerted no effect on TA1 cells. Rat adipose precursor cells possessed a single class of high affinity ET-1 receptor with a Kd of 0.71 nM and a binding capacity of 47,000 sites/cell. Affinity cross-linking of [125I]ET-1 showed two bands with molecular masses of 86 and 50 kilodaltons in rat adipose precursor cells and a single broad band with a molecular mass of 55-60 kilodaltons in TA1 cells. Pertussis toxin and the protein kinase-C inhibitors, H-7 and staurosporine, all of which enhanced adipocyte differentiation of rat adipose precursor cells, partially reversed ET-1 inhibition. These results showed the divergent effect of ET-1 on adipocyte conversion and indicated the possible involvement of a pertussis toxin-sensitive pathway and protein kinase-C at least in part in the inhibitory action of ET-1 on adipocyte differentiation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

In vitro replication study of modified bases in ras sequences.

DNA templates containing a modified base (O6-methylguanine, 8-hydroxyguanine, xanthine or hypoxanthine) which was located in nucleotide sequences corresponding to the 12th or 61st codon of a ras gene were synthesized and deoxynucleotide incorporation opposite the lesions was investigated. The templates were replicated by Taq DNA polymerase, recombinant rat DNA polymerase beta and mouse DNA polymerase alpha-primase complex. Sequence analysis of the replicated products indicated selective incorporation of nucleotide(s) opposite a modified base, depending on the kind of base and of DNA polymerase. This system is very useful to obtain results of in vitro replication of modified bases in ras sequences.

Animals↗
PubMed1992

Effect of captopril on isoproterenol-induced cardiac hypertrophy and polyamine contents.

It is well known that isoproterenol (ISO) a nonselective beta adrenoceptor agonist induces cardiac hypertrophy. It can be assumed that, in addition to its direct cardiac effect, ISO has a cardiac trophic effect via stimulation of the renin angiotensin system. Synthesis of polyamines is facilitated in cardiac hypertrophy and polyamine levels are rapidly elevated prior to an increase in heart weight. In the present study, we investigated whether captopril (30 mg/kg body weight, daily) could attenuate cardiac hypertrophy and elevation of cardiac polyamine levels in rats, which effects were elicited by a chronic (1- or 2-weeks) and repeated administration of a small dose (0.5 mg/kg body weight) of ISO. Cardiac hypertrophy was assessed by an increase in the wet weight and RNA content of the heart. Polyamines were analyzed by HPLC. Captopril alone did not affect either heart weight/body weight ratio or cardiac contents of polyamines and nucleic acids at the end of the second week. In isoproterenol-treated rats, the above parameters, except for putrescine content on day 14, were significantly increased on both day 7 and day 14. Captopril slightly attenuated ISO-induced cardiac hypertrophy and significantly prevented the ISO-evoked increase in the contents of RNA, spermidine, and spermine at the end of the second week. These results suggest that the ISO-evoked increase in cardiac polyamines was mediated, at least in part, by the renin angiotensin system, which was stimulated by ISO.

Animals↗
PubMed1992

ST-segment re-elevation and left ventricular expansion soon after acute anterior myocardial infarction.

The sum of ST-segment elevation (sigma ST on V2-4) was measured to evaluate ST-segment re-elevation during early convalescence in 57 patients with acute myocardial infarction. Following rapid ST-segment elevation resolution during the first 12 h, sigma ST again increased in many patients without signs of reinfarction or pericarditis, reaching a maximum approximately 5 days after onset. The magnitude of this re-elevation (delta sigma ST) was less than 0.3 mV in 30 patients (group A), and 0.3 mV or more in another 27 (group B). Based upon left ventriculography, the global ejection fraction in group B decreased significantly from 51 +/- 10% at the acute phase to 46 +/- 10% at the chronic phase. No such decreases were seen for group A. Regional ejection fraction in the infarcted portion improved significantly from 28 +/- 13% at the acute phase to 35 +/- 14% at the chronic phase in group A, but did not improve in group B. In addition, the non-infarcted portion in group B showed a significantly reduced regional ejection fraction. These results suggest that myocardial expansion of the infarcted portion may contribute to ST-segment re-elevation, an ominous sign of left ventricular dysfunction soon after acute myocardial infarction.

Cineangiography↗
PubMed1992

Histopathological factors related to diastolic function in myocardial hypertrophy.

To clarify the histopathologic influence on diastolic function in the hypertrophied heart, we compared the echocardiographic and histopathologic findings in 9 controls, 10 patients with hypertrophic cardiomyopathy (HCM), and 8 hypertensive patients with asymmetric septal hypertrophy (HT-ASH). M-mode echocardiography was used to determine the left ventricular diastolic function. Mean diameter of myocytes, percentage of fibrosis and disarrangement were quantitatively calculated from right ventricular endomyocardial biopsy specimens. In both HT-ASH and HCM, the isovolumic relaxation time was significantly longer and the rapid filling volume tended to be smaller than in the controls. Histopathologically, the mean diameter of myocytes and percentage of myocardial interstitial fibrosis did not differ significantly between HT-ASH and HCM. However, quantitative disarrangement of myocytes in HCM was significantly greater than that in HT-ASH. Multiple regression analysis showed that the percentage of fibrosis was the most significant factor related to diastolic left ventricular dysfunction in HT-ASH, while disarrangement of myocytes was the most significant in HCM. We conclude that diastolic dysfunction in HT-ASH can be attributed to the percentage of fibrosis, and to disarrangement of myocytes in HCM.

Adult↗
PubMed1992

Residual critical coronary stenosis during myocardial reperfusion is deleterious to myocardial salvage in dogs.

Hyperemia, which occurs immediately after coronary reperfusion, injures the myocardium. Mild coronary stenosis may mitigate this hyperemia and thus may augment myocardial salvage. To test this hypothesis, left anterior descending coronary arteries of dogs were occluded for 3 h. Then, reperfusion was permitted without residual stenosis (group A, n = 17) or with 75% stenosis (group B, n = 10). Regional myocardial blood flow (RMBF) was determined using colored microspheres. Dogs were sacrificed 1 week later to measure myocardial creatine kinase activity (CK) and for staining with triphenyl tetrazolium chloride (TTC). The RMBF measured 5 min after reperfusion increased significantly (inner layer, 171 +/- 16; outer layer, 165 +/- 11% of control) in group A. This hyperemia disappeared in group B (inner, 106 +/- 8; outer, 117 +/- 10% of control). However, the myocardial CK was more preserved (group A: inner, 31 +/- 4; outer, 44 +/- 4%; and group B: inner, 21 +/- 6; outer, 29 +/- 5%), and the infarct size was smaller in group A than in group B (group A: inner, 44 +/- 6; outer, 33 +/- 5; and group B: inner, 53 +/- 10; outer, 58 +/- 7% of the area at risk). We concluded that a residual stenosis of 75% at reperfusion abolishes the hyperemia but does not improve myocardial salvage.

Animals↗
PubMed1992

Insecticidal activity and processing in larval gut juices of genetically engineered 130-kDa proteins of Bacillus thuringiensis subsp. aizawai.

The 130-kDa insecticidal protein (IP) of Bacillus thuringiensis subsp. aizawai is proteolytically processed in the gut juice of susceptible insect larvae to yield an insecticidally active 60-kDa fragment. Twenty-seven mutant IP genes with the replacement of codons for Arg and Lys with codons for Gln in the active fragment and its adjacent regions of the 130-kDa IP were constructed by site-directed mutagenesis and expressed in Escherichia coli cells. The produced mutant IPs at Arg87, Arg131, Arg198, Arg311, Arg368, Arg402, Arg458, Arg502, Arg512, Arg524, Arg526, Arg528, and Arg601 had reduced insecticidal activity against Spodoptera litura larvae. The mutant at Arg601 was sensitive to proteolytic digestion in the gut juice of S. litura larvae. Although the mutants at Arg619, Lys622, and Lys637 had nearly the same activity as that of the wild type, the mutant with the triple replacement at Arg619, Lys622, and Lys637 was 2.5 times more active against S. litura larvae than the wild type. This triple mutant showed a slightly different processing profile in the gut juice than that of the wild type.

Amino Acid Sequence↗
PubMed1992

Molecular stability of chicken and rabbit immunoglobulin G.

Molecular stability of chicken egg yolk immunoglobulin G (IgY) and that of rabbit IgG were compared by measuring antibody activities and conformational changes. Stability of rabbit IgG to acid denaturation was much higher than that of IgY. Conformation of the IgY molecule was readily changed in acidic conditions, resulting in a rapid loss of antibody activity. Much less stable natures of IgY to heat-treatment and guanidine-HCl denaturation than rabbit IgG were also observed. Differences in the structure between the two immunoglobulins that might participate in their different stability were inferred from their amino acid sequence data. Importance of the intramolecular disulfide linkage in the rabbit light chain and some other structural differences were suggested.

Animals↗