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Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 217 records · Page 12Linked to original sources
PubMed1995

The pegs on the decorated tubules of the contractile vacuole complex of Paramecium are proton pumps.

Our previous study has shown that the decorated tubules (collectively known as the decorated spongiome) of the contractile vacuole complex (CVC) in Paramecium are the site of fluid segregation, as the binding of microinjected monoclonal antibody (mAb) DS-1 to the tubules reduced the CVC's fluid output. In this study, we showed by immunogold labeling on cryosections that the antigenic sites for mAb DS-1 were located on the 15 nm 'pegs' protruding from the cytosolic surface of the decorated tubules. In immunofluorescence studies, both polyclonal antibodies against the subunits of the V-ATPase of Dictyostelium discoideum and against the 57 kDa B-subunit of the V-ATPase of chromaffin granules gave identical labeling patterns to that produced by mAb DS-1. On cryosections, all three antigens were located most consistently near or on the pegs of the decorated tubules. These data support the notion that the pegs on the membrane of the decorated tubules represent the V1 complex of a proton pump. Concanamycin B, a potent inhibitor of V-ATPase activity and of acidification of lysosomes and endosomes, strongly and reversibly inhibited fluid output from the CVC but had minimal effect on the integrity of the decorated spongiome as observed by immunofluorescence. Such inhibition suggests that a V-ATPase is intimately involved in fluid segregation. Exposing Paramecium to 12 degrees C or 1 degrees C for 30 minutes resulted in the dissociation of the decorated tubules from the smooth spongiome that borders the collecting canals; thus the DS-1-reactive A4 antigen, the 75 kDa and 66 kDa antigens were all found dispersed in the cytosol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Rapid bulk replacement of acceptor membrane by donor membrane during phagosome to phagoacidosome transformation in Paramecium.

The extent to which a donor membrane will be retrieved, or if it is retrieved at all after it fuses with an acceptor membrane, is usually difficult to determine. We have studied the dynamics of membrane retrieval in the phagosome system of Paramecium multimicronucleatum using six monoclonal antibody markers. Our previous freeze-fracture and transmission electron microscopic studies have indicated that extensive changes take place in the membrane of the young phagosome as it progresses through its cycle. Using immunofluorescence and immunoelectron microscopy to determine the times of entry and exit of these individual antigens into the digestive vacuole system, we showed that two hydrophilic antigens, one located on the cytosolic and one on the lumenal side of the discoidal membrane (phagosome membrane precursor), were completely retrieved from the phagosome by tubulation within the first three minutes. At the same time that this membrane was retrieved, membrane from a second population of vesicles, the acidosomes, fused with the phagosome to produce the phagoacidosome. On the basis of immunogold localization on cryosections of a total of six antigens, the two specific for phagosome/discoidal vesicle membrane as well as four specific for the acidosome/phagoacidosome membrane, this replacement is total. We also showed that in the presence of the actin-active drug cytochalasin B, this replacement was essentially prevented. However, when vacuole acidification was neutralized by ammonium chloride, this replacement process continued unaffected after a lag. Consequently, acidification, per se, is not required to trigger the replacement of the phagosome membrane. We conclude, on the basis of these studies as well as our previous freeze-fracture studies that during phagoacidosome formation most of the acceptor membrane is retrieved and is replaced by the donor membrane. This shows that at least one cell type possesses the mechanisms needed to substantially replace the membrane of a phagosomal compartment when radical and rapid changes are needed to modulate the digestive and absorptive processes.

Ammonium Chloride↗
PubMed1995

Two kinds of neutral serine proteinases in salted muscle of anchovy, Engraulis japonica.

Two kinds of proteinases, type-I and type-II, were purified or partially purified from salted muscle of anchovy, Engraulis japonica. Mol. wts. of type-I and type-II proteinases were estimated to 25,000 and 37,000, respectively, on electrophoretic analysis. Both proteinases strongly hydrolyzed synthetic tri or tetrapeptide substrates specific to trypsin, alpha-thrombin, and an activated protein C, while they hardly hydrolyzed Arg-MCA and benzoyl Arg-MCA derivatives. The proteinases were inhibited by common trypsin inhibitors. Optimal pH for the proteinase activities were pH 6.8 (type-I) and pH 7.0 to 7.5 (type-II), and the proteinases showed the highest activities at 45 degrees C (type-I) and 50 degrees C (type-II). The N-terminal amino acid sequence of type-I proteinase, 1I-2V-3G-4G ... (29 residues were identified), was significantly similar to sequences of trypsins and tryptases. Based on these findings, both proteinases were presumed to be kinds of tryptases in E. japonica muscle.

Amino Acid Sequence↗
PubMed1995

The relationship between serum gamma-glutamyl transpeptidase levels and hypertension: common in drinkers and nondrinkers.

A significant association between elevations of serum gamma-glutamyl transpeptidase (gamma-GTP) levels and those of blood pressure and hypertension has been reported separately in drinkers and nondrinkers. The aim of the present study is to evaluate whether the relationship between serum gamma-GTP and the prevalence of hypertension is the same or similar in both drinkers and nondrinkers. The study subjects comprised 4,920 male nondrinkers, 9,390 male daily drinkers, 8,081 female nondrinkers, and 278 female daily drinkers, who were aged 40 to 59 years. The prevalence of hypertension in the male and female daily drinkers was 1.5 and 1.3 times, respectively, higher than in the nondrinkers. Mean systolic blood pressure in the male and female drinkers was 4.4 and 3.1 mmHg, respectively, higher than in the nondrinkers. After adjusting for age, body mass index, and serum gamma-GTP levels, the differences in the prevalence of hypertension and the mean systolic blood pressure level between the drinkers and nondrinkers decreased to 1.2 times and 2.7 mmHg, respectively. Although these small differences remained statistically significant, the association between serum gamma-GTP and hypertension appears to be quite similar in both drinkers and nondrinkers, suggesting that hepatic steatosis may play a common, pathogenetic role in the development of hypertension.

Adult↗
PubMed1995

Resistibility to Theileria sergenti infection in Holstein and Japanese Black cattle.

To clarify the resistibility against Theileria sergenti infection in Holstein and Japanese Black cattle under controlled conditions in artificial environmental chambers, those breeds of calves were infected with T. sergenti by infestation with the same number of infected ticks. No apparent differences between the two breeds were observed in the feeding numbers and feeding periods of ticks infested. The level and duration of parasitemia were clearly less and shorter in Japanese Black than those in Holstein calves. With progress of parasitemia, packed cell volume (PCV) and erythrocyte number decreased in both breeds. However, the minimum PCV and erythrocyte number recorded in Japanese Black were higher than those in Holstein calves. These results suggest that the Japanese Black shows solider resistance to T. sergenti infection than the Holstein breed does under experimentally controlled condition without external factors.

Animals↗
PubMed1995

Intraplatelet free calcium concentrations and alcohol-related blood pressure elevation in a middle-aged male population.

Elevated intracellular free calcium (Ca2+) has been proposed as a mechanism of alcohol-induced hypertension from animal experimental studies, but this has not been confirmed in man. In the present study, intraplatelet Ca2+ concentration (plt.[Ca2+]i) was measured in 83 middle-aged men, and the associations between alcohol consumption, age, body mass index (BMI), hematological and serum biochemical variables, plt.[Ca2+]i and blood pressure were analyzed. Plt.[Ca2+]i did not show a significant univariate correlation with alcohol consumption or with blood pressure, but did so with serum gamma-glutamyl transpeptidase (gamma-GTP) levels. Age, BMI and serum gamma-GTP were selected as independent contributors to blood pressure, and gamma-GTP alone was selected as the determinant of plt.[Ca2+]i by multiple regression analyses. The association between gamma-GTP and plt.[Ca2+]i was shown to be common or at least very similar in both drinkers and nondrinkers by generalized linear model analysis. Therefore, chronic alcohol consumption in humans may relate to elevations of plt.[Ca2+]i, not mainly by the direct action of alcohol but by some metabolic alterations after alcohol consumption. The significance of elevated plt.[Ca2+]i in drinkers in the development of hypertension, however, remains obscure.

Adult↗
PubMed1995

Serum levels of six pancreatic enzymes as related to the degree of renal dysfunction.

OBJECTIVES: Currently, serum total amylase, pancreatic isoamylase (P-amylase), lipase, trypsin(ogen), phospholipase A2 (PLA2), and elastase I are advocated to be useful in diagnosing pancreatic diseases. However, the most useful among the above six enzymes in patients with impaired renal function has not been fully clarified. We, therefore, studied the relation of the serum levels of the above enzymes and creatinine clearance (CrCl) in normal controls and patients with chronic renal insufficiency or failure. METHODS: PLA2 and elastase I were assayed by RIA, trypsin(ogen) by EIA and others by activity. Subjects were 24 healthy controls and 47 patients with impaired renal function and no apparent pancreatic diseases. RESULTS: 1) Elastase I was significantly elevated only in patients with a CrCl of 10 ml/min or less, whereas others were elevated already in patients with a CrCl below 40 ml/min; 2) in 12 patients with a CrCl between 13 and 39 ml/min, lipase tended to be less frequently raised than others, except elastase I, although the difference was statistically insignificant; 3) in 28 patients with a CrCl between 40 and 74 ml/min, lipase was less frequently elevated than others, except elastase I and PLA2; 4) in seven patients with a CrCl of 10 ml/min or below, elastase I tended to be less frequently elevated than others, although the difference was statistically insignificant; and 5) the degree of elevation was within 2.5 times the upper limits of reference values in all enzymes, except trypsin(ogen) (within 4.8 times). CONCLUSIONS: Elastase I was least vulnerable to impaired renal function followed by lipase. We, therefore, recommend combined assays of elastase I and lipase for detecting pancreatic diseases in patients with renal insufficiency. When cut-off levels are set at 2.5 times the upper limit of reference values, P-amylase or PLA2 can replace lipase.

Aged↗
PubMed1995

[Characterization of peripheral blood natural killer (NK) cells in two patients with CD16+ CD56- NK cell-lineage granular lymphocyte-proliferative disorder].

In normal peripheral blood natural killer (NK) cells, the subset of CD16+ CD56+ cells is predominant, and that of CD16+ CD56- cells is rarely present. Because we have found the expansion of CD16+ CD56- NK cells in the peripheral blood of two patients with NK cell-lineage granular lymphocyte-proliferative disorders (NK-GLPD), the clinical findings and cellular characteristics of these patients were compared with those of CD16+ CD56+ NK-GLPD patients. Although CD16+ CD56- and CD16+ CD56+ NK-GLPD cells were morphologically different, clinical findings and courses, and NK activity did not differ significantly. Because strong NK activity was demonstrated in CD16+ CD56- NK-GLPD cells, the CD56 antigen, one of the adhesion molecules, did not seem to play a major role in NK cell-mediated cytotoxicity. The CD56 antigen is known to be more strongly expressed by immature NK cells than by mature NK cells. However, because interleukin 2-activated CD16+ CD56- NK-GLPD cells rapidly expressed the CD56 antigen, the degree of CD56 antigen expression did not always correlate with the maturity of NK cells.

Aged↗
PubMed1995

[Progressive pulmonary fibrosis in a case of Sjögren's syndrome with asbestos exposure].

A 62-year-old man had an occupational history of exposure to asbestos for 27 years (1947-1974). Dry mouth, dry eyes and swollen gums were noted in 1974. Sjögren's syndrome was diagnosed in 1975. The chest radiograph in 1984 showed bilateral pleural thickening and small reticular opacities in the left lower lung field. In 1990, he complained of dyspnea and cough, and diffuse interstitial pneumonia was diagnosed. While being treated for diffuse interstitial pneumonia, pulmonary fibrosis progressed rapidly, and advanced pulmonary fibrosis was obvious in 1992. Laboratory data showed hyper gamma-globulinemia (36.8%) and a high level of IgG (3772 mg/dl) in 1976. These values decreased to within the normal ranges during the subsequent clinical course. The results of lymphocyte subset counts in 1988 were normal. With the progression of diffuse interstitial pneumonia in 1990, the lymphocyte subset counts showed a low percentage of CD4 (19.2%), a low CD4/8 ratio (0.46), and a low percentage of CD20 (26.8%). In 1992, as pulmonary fibrosis progressed despite treatment, the disorder of lymphocyte subsets became worse. The CD4 percentage was very low (5.0%), as was the CD4/8 ratio (0.08), and the percentage of CD20 (1.4%); the CD8 percentage was high (64.7%), as was the percentage of Leu 7 (49.0%). These immunologic and pulmonary changes could be not explained by Sjögren's syndrome. Determining what factor induced these changes is difficult, but asbestos exposure is a likely cause.

Asbestos↗
PubMed1995

[Corneal autofluorescence in patients with diabetic retinopathy].

Corneal autofluorescence was investigated by fluorophotometry in patients with non-insulin-dependent diabetes mellitus and healthy volunteers, and evaluated as to its correlation with diabetic retinopathy. The corneal autofluorescence of diabetes patients, which was significantly higher than that of healthy controls, correlated significantly with the severity of retinopathy. In addition, the corneal autofluorescence of burned-out retinopathy patients was significantly lower than that of proliferative retinopathy patients. These results suggest that corneal autofluorescence is correlated with retinal ischemia and that corneal autofluorescence can be an indicator of the activity of diabetic retinopathy. Corneal autofluorescence may originate in the accumulation of some factor induced by retinal ischemia within the corneal stroma.

Adult↗
PubMed1995

Association between hepatic steatosis, insulin resistance and hyperinsulinaemia as related to hypertension in alcohol consumers and obese people.

The presence of hepatic steatosis was determined in 180 middle-aged male workers by ultrasonography and was found in 39 (22%) of them. Body mass index (BMI), systolic and diastolic blood pressure (BP) and serum levels of asparate aminotransferase (AST), alanine aminotransferase (ALT) and gamma-glutamyl transpeptidase (gamma-GTP) were higher in the subjects with hepatic steatosis. Although the volume of alcohol consumed in a week did not differ between the subjects with and without hepatic steatosis, the hepatic steatosis was thought to relate to both increased body mass and alcohol consumption because the elevations of serum AST and gamma-GTP in the subjects depended largely on alcohol consumption but not on BMI. The results of 75 g oral glucose tolerance test showed a higher blood glucose at 120 minutes and a higher plasma immunoreactive insulin at baseline, 60 and 120 minutes in the subjects with hepatic steatosis, being adjusted for age, BMI and alcohol consumption. The significant association between serum gamma-GTP and BP, which had been often observed in alcohol consumers, was no longer significant after adjustment for plasma insulin levels whereas plasma insulin showed a significant association with BP. These results suggest the possibility that hypertension in alcohol consumers, and also in obese people, relates at least partly to hyperinsulinaemia associated with progression in hepatic steatosis.

Alanine Transaminase↗
PubMed1995

Super-early iodine-123-iodoamphetamine SPECT imaging of human primary motor cortex.

UNLABELLED: This study was designed to visualize the motor function area related to finger movements in normal human brain using super-early (first 640 sec of acquisition) [123l]iodoamphetamine ([123I]IMP) SPECT. METHODS: Seven healthy male volunteers performed paired, isolated baseline and task sessions. The task was a right thumb-to-fingers opposition task, which was loaded for the initial 11 min of the session. A high-performance, four-head SPECT camera was used. At each session, administration of 222 MBq [123I]IMP was followed by 16 serial 160-sec dynamic SPECT acquisitions. To obtain matched brain anatomical images, MRI was also performed using the same slice formation as in the SPECT study. After image reconstruction, ROIs were set on bilateral sensorimotor hand areas (SMHA), the supplementary motor area (SMA), the frontal, temporal and occipital lobes and the cerebellar hemispheres. The percent increase of ROI activity (%INC) in the task session compared with that in the baseline session was calculated in each ROI after normalization to the global brain radioactivity. RESULTS: There was significant activation of the left SMHA by the task, the amplitude of which was maximal in the initial phase of dynamic images (the super-early phase). This area was located in the left peri-central area identified on the analogous slice in the MR image. The left SMHA showed gradual and statistically significant decrease of %INC during the three phases. CONCLUSION: Super-early [123I]IMP may be used to identify the primary motor cortex and to evaluate its function in some pathological conditions.

Adult↗
PubMed1995

Iron and copper deposition in chronic active hepatitis and liver cirrhosis; pathogenetic role in progressive liver cell damage.

Iron and copper deposition were examined in patients with chronic active viral hepatitis (CAH) and posthepatitic liver cirrhosis (LC) by Berlin blue, rhodanine, or Victoria blue staining and X-ray microanalysis. Considerable iron or copper deposition was demonstrated in the peripheral zones of hepatic lobules in both CAH (53% of specimens) and LC (63% of specimens). Frozen sections taken from the 2 CAH surgical sections with iron depositions were examined by photoncounting image analysis, and superoxide liberation from the metal granules were demonstrated. In areas of metal deposition, vacuolation of liver cell nuclei, accumulation of lipofuscin, and induction of metallothionein (69% of rhodanine- or Victoria blue-positive specimens) were often demonstrated, whereas induction of ferritin was found only in 14% of Berlin blue-positive specimens. The PCNA index was significantly lower in areas of metal deposition than in the adjacent areas without metal deposition, indicating lowered proliferative capability in the former. These results indicate that cell-mediated immune mechanisms causing the disturbance of bile secretion and heavy metal deposition in the peripheral zones of hepatic lobules may be involved in the progression of viral hepatitis from its acute phase to CAH and finally to LC phase, resulting in piecemeal necrosis. However, cholangitis could not be demonstrated in the present study.

Adult↗
PubMed1994

Efficacy of inactivated vaccine in preventing antigenically drifted influenza type A and well-matched type B.

OBJECTIVE: To evaluate the efficacy of currently used inactivated influenza vaccine during a severe epidemic caused by antigenically drifted influenza type A(H3N2) and well-matched type B viruses during the 1992-1993 season. DESIGN: Prospective nonrandomized controlled trial. SETTING: An urban general hospital pediatric asthma clinic in Japan. PARTICIPANTS: A total of 137 children with moderate to severe asthma (mean age, 7.0 years; range, 2 to 14 years). INTERVENTION: Eighty-five children received trivalent split-antigen vaccine containing A/Beijing/352/89 (H3N2) and B/Bangkok/163/90 (B/Panama/45/90-like strain). Fifty-two were unvaccinated. MAIN OUTCOME MEASURES: Protection against infection was determined using hemagglutination inhibition test and virus isolation. Clinical efficacy was estimated based on febrile episodes with antibody rise or virus isolation. RESULTS: Although marked antigenic drift in hemagglutinin was demonstrated in the epidemic virus (A/Beijing/32/92-like strain), the protection against influenza type A(H3N2) infection was 67.5% (P < .01). The protection against influenza type B infection was 43.7% (P < .01), although the epidemic influenza type B viruses were antigenically almost identical to the vaccine strain. Inactivated vaccine was not effective for protection against influenza type B infection in children younger than 7 years. High clinical effectiveness was demonstrated in children at least 7 years of age during the epidemic. CONCLUSIONS: Our data suggest that current inactivated vaccine is highly effective for protection against influenza type A(H3N2) virus infection regardless of antigenic drift. In contrast, the protective efficacy obtained by vaccination may not be sufficient against influenza type B virus infection, and especially in young children, it does not offer protection.

Adolescent↗
PubMed1994

Agonists for metabotropic glutamate receptors in the rat delay recovery from halothane anesthesia.

Intraventricular injection of (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV), a potent agonist for metabotropic glutamate receptors, to rats retarded dose-dependently the recovery from halothane anesthesia at a dose range from 30 to 300 pmol/rat. At a dose of 300 pmol/rat, recovery was prolonged up to about 630% of the control. (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) and (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD) also delayed recovery, but doses much higher than those of DCG-IV were required (about 300 and 1000 times, respectively). These results suggest that some agonists for a certain kind of metabotropic glutamate receptors have a central depressant action in the rat.

Adenylyl Cyclase Inhibitors↗
PubMed1994

A novel metabotropic glutamate receptor agonist: (2S,1'S,2'R,3'R)-2-(2-carboxy-3-methoxymethylcyclopropyl)glycine (cis-MCG-I).

A novel agonist for metabotropic glutamate receptors, (2S,1'S,2'R,3'R)-2-(2-carboxy-3-methoxymethylcyclopropyl)glycine (cis-MCG-I), effectively inhibited monosynaptic excitation in newborn rat spinal cords with EC50 of 3 microM without causing any depolarization. Furthermore, cis-MCG-I inhibited the forskolin-stimulated cyclic AMP formation in rat cultured cortical cells with IC50 of 1.5 microM. cis-MCG-I neither stimulated the phosphoinositide hydrolysis nor activated ionotropic glutamate receptors even in high concentrations. However, after a brief exposure of spinal cords to quisqualate, it caused depolarization in a dose-dependent manner. This compound would provide useful information for elucidating physiological functions of metabotropic glutamate receptors.

Animals↗
PubMed1994

Determination of carbenicillin epimers in plasma and urine with high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed for determining the concentrations of carbenicillin (CBPC) epimers in plasma and urine. Samples were prepared for HPLC analysis by solid-phase extraction and the concentrations of CBPC epimers were determined using reversed-phase HPLC with a mixture of 0.05 M ammonium acetate and methanol as a mobile phase. Baseline separation of the two epimers was observed for both plasma and urine samples with a detection limit of ca. 10 micrograms/ml. No peaks interfering with either of the CBPC epimers were observed on the HPLC chromatograms for blank plasma and urine. The presented method was used to determine the protein binding of CBPC epimers in vitro in human and rabbit plasma. The stereoselectivity of the binding of CBPC appeared to be reversed in human and rabbit plasma.

Adult↗