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Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 181 records · Page 10Linked to original sources
PubMed1996

Apoptosis occurs more frequently in metastatic foci than in primary lesions of human colorectal carcinomas: analysis by terminal-deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling.

We examined the occurrence of apoptotic cell death in 15 advanced colorectal carcinomas with lymph-node and/or liver metastases by terminal-deoxynucleotidyl-transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL). TUNEL-positive cells were used to quantify the apoptotic index (AI: percentage of TUNEL-positive cells in carcinomatous cells). Similarly, Ki-67-positive cells were used to quantify Ki-67 labeling (KI: percentage of Ki-67-positive cells in carcinomatous cells) as a proliferative index. The mean AIs of primary colorectal carcinomas, lymph-node and liver metastases were 3.5%, 5.6% and 6.2% respectively. There was a significant group difference between primary carcinomas and lymph-node or liver metastases. The mean KIs of primary colorectal carcinomas, lymph-node and liver metastases were 51.8%, 60.1% and 61.7% respectively. There was a significant group difference between primary carcinomas and lymph-node or liver metastases. In addition, there was a close positive relationship between the AI and MI per specimen. There was no apparent correlation between AI or MI and the expression of nuclear p53 of cancer cells. These results suggested that cell proliferation and loss (apoptosis) were more frequent in metastatic foci than in primary lesions, and that apoptosis might reflect not only cell loss but also the proliferative activity of human colorectal carcinomas.

Apoptosis↗
PubMed1996

A leader open reading frame is essential for the expression in Escherichia coli of GC-rich leuB gene of an extreme thermophile, Thermus thermophilus.

To improve expression efficiency of the leuB gene of an extreme thermophile. Thermus thermophilus, in Escherichia coli, the gene was placed under a potent promoter, tac. However, the expression was hardly improved, despite increased transcription. The expression under tac promoter was significantly improved by introducing a leader open reading frame in front of the gene. Similar improvement under a weak promoter, tet, with a leader open reading frame had been described previously. The present results provide evidence that the major limiting step in the expression of a GC-rich thermophile gene in E. coli is translation, and that the addition of a leader open reading frame is more crucial for high level expression of the gene than the use of a potent promoter.

Antigens, Differentiation↗
PubMed1996

Decreases in postural change in finger blood flow in ceramic painters chronically exposed to low level lead.

To elucidate the effect of low level lead (Pb) exposure on somatic and autonomic peripheral nerve functions in ceramic painters, 58 males and 70 females, aged 29-75 years (mean 53.3 years), with lead concentrations in blood (Pb-B) ranging from 2.1 to 69.5 micrograms/dl (geometric mean 13.3 micrograms/dl), were examined for median nerve maximal conduction velocity as a measure of motor nerve function, the coefficient of variation of R-R interval on electrocardiography as a measure of parasympathetic function, and postural changes in finger blood flow volume (delta FBF), and changes in finger blood flow drop velocity (FDV) from the supine to standing position as a measure of sympathetic function. No significant association was found between Pb-B levels and the results of the neurophysiological tests, however, except for that between Pb-B and delta FBF was decreased linearly with increasing Pb-B levels. However, this association could not be concluded to be a reflection of sympathetic nerve dysfunction due to Pb exposure in the subjects, since delta FBF was not a specific parameter of sympathetic nerve function. The possibility that the decrease in delta FBF is a reflection of the atherosclerotic effect of chronic low level Pb exposure should be further investigated.

Analysis of Variance↗
PubMed1996

Age-related changes in the localization of glycosaminoglycans in condylar cartilage of the mandible in rats.

There is little information available regarding the morphological and biomolecular characteristics of mandibular condylar cartilage. The purpose of this study was to determine the age-related changes in the morphology and immunolocalization of glycosaminoglycans (GAGs) in mandibular condyles. The mandibular condylar cartilages from 4-, 8-, 16-, 32-, and 64-week-old Wistar male rats were examined to verify the localization of chondroitin-4-sulfate (Ch-4S), chondroitin-6-sulfate (Ch-6S) and keratan sulfate (KS) using an indirect immunofluorescent technique with three monoclonal antibodies for glycosaminoglycans, 2-B-6, 3-B-3 and 5-D-4, respectively. Morphologically, the condylar cartilage was a growth cartilage during growing periods, began to differentiate into articular cartilage from the central area of 16-week-old condyles, and became mature articular cartilage at 32 weeks of age. A regional difference was found in the morphological features and distribution of GAGs between the anterior, central, postero-superior and posterior areas of the condyles at each age. The immunohistochemical localizations of these three glycosaminoglycans showed age-related, morphology-dependent changes, from growth cartilage to articular cartilage-like cartilage. Immunoreactions for all of the antibodies decreased progressively with age in the interterritorial matrix, while the pericellular and territorial matrix in the condylar cartilage of the mandible maintained relatively higher immunoreactivity. In conclusion, age-related and regional differences in the localization of glycosaminoglycans Ch-4S, Ch-6S, and KS were found in the mandibular condyles in rats, and these changes are believed to be related to functional and developmental requirements.

Aging↗
PubMed1996

Apoptosis in human gastric mucosa, chronic gastritis, dysplasia and carcinoma: analysis by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling.

We examined the existence and distribution of apoptotic cells in human gastric mucosa, chronic gastritis, adenomatous dysplasias and carcinomas in 15 surgically removed stomachs in which dysplasia and carcinoma were found simultaneously. Serial sections were cut for immunohistochemistry for p53 oncoprotein and Ki-67 antigen, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labelling (TUNEL). TUNEL signal-positive apoptotic cells were rare in normal mucosa, while a few apoptotic cells were noted in gastritic mucosa and intestinal metaplasia, intermingled with Ki-67 antigen-positive cells forming a generative cell zone. This suggests the cell-cycle-dependent apoptosis of gastric mucosa. The frequency of apoptotic cells per crypt was higher in incomplete than in complete metaplasia, implying greater underlying DNA damage in the former. TUNEL indices (TI: percentage of TUNEL-positive cells in tumour cells) were slightly higher in adenomatous dysplasias (4.9 +/- 2.1) than in carcinoma (3.9 +/- 1.1), but there was no no statistical difference. Ki-67 indices (KI: percentage of Ki-67 antigen-positive cells in tumour cells) were significantly (P < 0.05) higher in carcinomas than in dysplasias. Thus, gastric adenomatous dysplasias were characterized by relatively higher TI and lower KI, which might reflect a more static growth potential. The expression of p53 oncoprotein in cancer cells is thought to be an apoptosis-suppressing event, although its precise role remains to be elucidated. Overall, these results indicate that apoptosis plays a crucial part in the morphogenesis of gastritic mucosa including intestinal metaplasia, and that the process is correlated both with tumourigenesis and with proliferative activity.

Adenoma↗
PubMed1996

Evolutionary characterization of recent human H3N2 influenza A isolates from Japan and China: novel changes in the receptor binding domain.

Recent human H3N2 influenza viruses isolated in Japan and China were characterised from an evolutionary point of view. They appeared to have divided into three minor branch clusters, including 1992-1993, 1993-1994 and 1994-1995 isolates. It was of particular interest to reveal that in addition to amino acid substitutions in the antigenic sites of the HA molecule, amino acid changes occurred at position 226 of the receptor binding site from lysine or glutamine to isoleucine in all strains belonging to the 1994-1995 branch cluster. This is the first evidence of human H3N2 influenza isolates, or any other influenza HA serotypes, to contain a conserved amino acid residue other than lysine or glutamine at this key position.

Amino Acid Sequence↗
PubMed1996

A polypeptide toxin in the sea anemone Actinia equina homologous with other sea anemone sodium channel toxins: isolation and amino acid sequence.

The sea anemone (Actinia equina) was newly established to contain a polypeptide toxin (named Ae I) having lethal activity to crabs, besides the well-known cytolytic toxins (equinatoxins) of proteinic nature. Ae I, with a minimum lethal dose against crabs of 25 micrograms/kg, was easily isolated by gel filtration on Sephadex G-50 and reverse-phase HPLC on Nucleosil 300-7C18. Its amino acid composition is characterized by the abundance of Gly, the absence of Ala and the presence of Met. The complete amino acid sequence of Ae I was determined. Ae I has high sequence homology with type 1 sea anemone neurotoxins. Interestingly, the polypeptide chain of Ae I comprises 54 amino acid residues, being 5-8 residues longer than the known type 1 toxins having 46-49 residues.

Amino Acid Sequence↗
PubMed1996

Neurotoxicity of (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine, a potent agonist for class II metabotropic glutamate receptors, in the rat.

Neurotoxicity of (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl)glycine (DCG-IV), a potent agonist for metabotropic glutamate receptors negatively coupled to adenylyl cyclase, was investigated in vivo by the intraventricular administration in the rat, compared with that of (2S,1'S,2'S)-2-(carboxycyclopropyl)glycine (L-CCG-I) and (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid [(1S,3R)-ACPD]. Neither L-CCG-I nor (1S,3R)-ACPD caused any apparent pathological change in the brain at an intraventricular dose of 1 mumol, whereas DCG-IV induced selective neuronal damage in some rats at higher doses than 3 nmol. The neurotoxicity was intensified in a dose-dependent manner, and at a dose of 50 nmol DCG-IV caused repetitive seizures and selective neuronal damage in all cases. Neuronal damage was pronounced in the cingulate cortex, lateral septum and hippocampus, and a few degenerating neurons were observed also in other brain areas, such as the striatum, thalamus or neocortex. Since DCG-IV activates N-methyl-D-aspartate-type receptors as well at relatively high concentrations, the protective effect of a competitive antagonist for N-methyl-D-aspartate receptors, 3-[(RS)-2-carboxypiperazin-4-yl]propyl-1-phosphonic acid (CPP), was examined on the neurotoxicity of DCG-IV. Although a combined treatment with CPP (0.1 nmol) completely blocked the neurotoxicity of N-methyl-D-aspartate (100 nmol), at least 3 nmol of CPP was necessary to decrease the neurotoxicity of DCG-IV (50 nmol) to a considerable extent. The synergistic activation of metabotropic glutamate receptors and N-methyl-D-aspartate receptors is suggested as a possible mechanism underlying the selective neuronal damage induced by DCG-IV, although a direct participation of metabotropic glutamate receptors in glutamate neurotoxicity is not deniable.

Animals↗
PubMed1996

No interaction between desipramine and bromperidol.

1. The authors studied the effects of coadministration of desipramine, which is a substrate of CYP2D6, on plasma concentrations of bromperidol and its reduced metabolite (reduced bromperidol). Clinical changes were also evaluated by the CGI and UKU. 2. The subjects were 13 schizophrenic inpatients receiving bromperidol 12.24 mg/day for 1.20 weeks. Desipramine 50 mg/day was coadministered for 1 week, and blood samplings and clinical ratings were performed before and after the coadministration. 3. Plasma concentrations of bromperidol and reduced bromperidol were measured by a HPLC method. 4. Desipramine coadministration did not affect plasma concentration of bromperidol (9.6 +/- 4.5 vs. 9.6 +/- 2.8 ng/ml) nor that of reduced bromperidol (2.8 +/- 2.5 vs. 2.8 +/- 2.1 ng/ml). 5. There was no significant change in the CGI scores nor UKU scores after desipramine coadministration. 6. The present study thus suggests that there is no interaction between desipramine and bromperidol.

Adult↗
PubMed1996

Plasma prolactin concentration and psychopathology of schizophrenia.

1. The correlation between plasma prolactin concentration and psychopathology, as assessed by the BPRS, was studied in 56 unmedicated schizophrenic patients (28 males, 28 females). 2. There was no significant correlation between plasma prolactin concentration and total BPRS score or each item score. 3. No significant correlation was found when the BPRS items were classified into five clusters, i.e., positive, excitement, cognitive, negative, and anxiety-depression symptoms. 4. When males and females were analyzed separately, no significant correlation was found except a weak negative correlation (rs = -0.388, p < 0.05) for hostility score in females. 5. The present study suggests that plasma prolactin concentration does not reflect psychopathology of schizophrenia.

Adolescent↗
PubMed1996

Purification of an alpha,beta-ketoalkene double bond reductase from Salmonella typhimurium.

An alpha, beta-ketoalkene double bond reductase was purified from the cell-free extract of Salmonella typhimurium. The purified enzyme was homogeneous by the criterion of sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of the enzyme was estimated to be 24,700 by the electrophoresis and 23,900 by HPLC gel filtration, respectively. The isoelectric point is pH 7.2. The enzyme in the presence of NAD(P)H exhibited double bond reductase activity toward alpha, beta-ketoalkenes such as trans-phenyl-1-propenyl ketone, trans-benzylideneacetophenone and 15-ketoprostaglandins. The enzyme activity was markedly inhibited by dicumarol.

Alprostadil↗
PubMed1996

Effects of carbamazepine coadministration on plasma concentrations of trazodone and its active metabolite, m-chlorophenylpiperazine.

Effects of carbamazepine coadministration on plasma concentrations of trazodone and its active metabolite, m-chlorophenylpiperazine (m-CPP) were studied in six depressed patients treated with trazodone. The daily dose of trazodone was 150 mg in three cases and 300 mg in three cases. Carbamazepine, 400 mg/day, was coadministered for 4 weeks, and blood samples were taken before carbamazepine addition and at weekly intervals after the addition. Carbamazepine significantly (p < 0.01) decreased plasma concentrations of not only trazodone but also m-CPP at each week. On the average, plasma concentrations of trazodone and m-CPP at 4 weeks were 24 and 40% of the corresponding precarbamazepine values. This study thus suggests that carbamazepine coadministration decreases plasma concentrations of trazodone and m-CPP by inducing the metabolism of these compounds.

Anticonvulsants↗
PubMed1996

Large outbreak of swine influenza in southern Japan caused by reassortant (H1N2) influenza viruses: its epizootic background and characterization of the causative viruses.

In the winter of 1989 and the spring of 1990, there were large outbreaks of respiratory disease in two swine herds in Nagasaki Prefecture, southern Japan. Serological surveillance indicated that the majority of swine possessed antibodies to swine influenza virus H1 haemagglutinin and neuraminidase of early H3N2 influenza virus strains. Eight viruses were isolated from swine that showed typical clinical symptoms of influenza. The haemagglutinin and neuraminidase of these isolates were closely related to those of swine H1N1 and early human H3N2 viruses, respectively. At least two types of haemagglutinin antigens, distinguished by two monoclonal antibodies, were involved in the outbreaks. Evolutionary analyses indicated that the haemagglutinin gene of the H1N2 reassortants was closely related to those of a recent swine lineage (A/sw/HK/1/74 and A/sw/Ehime/1/80 viruses). However, the neuraminidase genes of the H1N2 reassortants were similar to those of swine N2 viruses which in turn are related to early human H3N2 viruses. A comparison of partial nucleotide sequences revealed that the six other genes of A/sw/Nagasaki/1/89 were derived from those of swine H1N1 virus.

Animals↗
PubMed1996

Angiotensin I-converting enzyme gene polymorphism and salt sensitivity in essential hypertension.

We undertook the present study in 66 Japanese patients with essential hypertension to identify genetic factors associated with salt sensitivity. Patients were classified into salt-sensitive or salt-resistant groups on the basis of changes in their mean blood pressures from a week of a low salt diet (50 mmol/d) to a week of a high salt diet (340 mmol/d). Salt sensitivity and resistance were studied in relation to a 287-bp insertion/deletion (I/D) polymorphism of the angiotensin I-converting enzyme gene detected by a polymerase chain reaction method and the haptoglobin phenotype determined by polyacrylamide gel electrophoresis. Patients with the angiotensin I-converting enzyme gene genotype II were more apt to be salt sensitive than patients with the ID and DD genotypes, although plasma renin activity was similar in each group. The frequency of the I allele in the salt-sensitive group was significantly higher than that in the salt-resistant group (chi2 = 7.4, odds ratio = 2.78). However, there was no significant relationship between haptoglobin phenotype and salt sensitivity. These data suggest that an I/D polymorphism of the angiotensin I-converting enzyme gene is a genetic factor associated with salt sensitivity of blood pressure independently of plasma renin activity in Japanese patients with essential hypertension.

Adult↗
PubMed1996

Platelet Ca2+ is not increased in stroke-prone spontaneously hypertensive rats: comparative study with spontaneously hypertensive rats.

We have reported that cytosolic Ca2+ concentration ([Ca2+]i) is increased in platelets from spontaneously hypertensive rats (SHR) in both basal and thrombin-stimulated conditions. To determine whether the correlation between blood pressure and cellular Ca2+ metabolism exists in stroke-prone SHR (SHRSP), we investigated Ca2+ handling using fura 2 and aggregation response in platelets of 12- to 13-week-old male SHRSP, SHR, and Wistar-Kyoto rats (WKY). Systolic pressure was highest in SHRSP and lowest in WKY (213 +/- 8, 172 +/- 7, and 135 +/- 5 mm Hg, respectively). Basal [Ca2+]i was significantly higher in SHR than WKY (45.9 +/- 4.5 versus 41.2 +/- 4.8 nmol/L, P<.05), and that in SHRSP (40.2 +/- 2.8 nmol/L) was similar to that in WKY. Thrombin (0.1 IU/mL)-stimulated [Ca2+]i rise was greater in SHR and smaller in SHRSP than in WKY in the presence of extracellular Ca2+ (530 +/- 50 and 408 +/- 52 versus 475 +/- 50 nmol/L, respectively; P<.05). The recovery rate from the peak [Ca2+]i response to thrombin was greatest in SHRSP and least in WKY. Ionomycin (5 micromol/L)-stimulated [Ca2+]i rise was similar in WKY, SHR, and SHRSP (731 +/- 97, 743 +/- 88, and 683 +/- 70 nmol/L, respectively). Thrombin-induced maximum platelet aggregation response was higher in SHR and lower in SHRSP than WKY (82 +/- 4 percent and 61 +/- 15 percent versus 73 +/- 6 percent, respectively; P<.05). In contrast to SHR, basal [Ca2+]i in SHRSP was similar to that in WKY, and thrombin-stimulated [Ca2+]i was attenuated. These result suggest that platelet Ca2+ handling differs between SHR substrains and that an increased [Ca2+]i is not obligatory in genetically hypertensive rats.

Animals↗
PubMed1996

Effects of insulin on calcium metabolism and platelet aggregation.

The influence of insulin on platelets in vitro has not been exhaustively investigated. To clarify whether insulin affects Ca2+ metabolism in platelets directly or through alteration of other systems regulating intracellular Ca2+ homeostasis, we examined the effect of insulin both alone and in combination with prostaglandin E1 on platelet aggregation and Ca2+ metabolism. Incubation of rat platelets with insulin reduced thrombin-induced Ca2+ influx but did not change thrombin-evoked release of Ca2+ from internal stores or the size of internal Ca2+ stores. The interactive effects of insulin with prostaglandin E1 were only additive, and insulin did not augment the effects of prostaglandin E1 on platelet Ca2+ metabolism. In contrast, insulin did not inhibit thrombin-induced platelet aggregation but did augment inhibition of platelet aggregation by prostaglandin E1. Our results suggest that insulin inhibits platelet function by both prostaglandin E1-dependent and -independent mechanisms.

Animals↗
PubMed1996

Hyperosmotic stress leads to reversible dissociation of the proton pump-bearing tubules from the contractile vacuole complex in Paramecium.

To study the effect of hyperosmotic stress on the structure and function of the contractile vacuole complex of Paramecium multimicronucleatum, we employed two different monoclonal antibody markers: one to a decorated spongiome antigen (A4) and a second to an antigen found on all other membranes of the contractile vacuole complex (G4). A hyperosmotic condition was produced by adding sorbitol to the axenic culture medium which induced both dose- and time-dependent decreases in the vacuole's expulsion rate. The addition of 150 mM sorbitol to the medium (making a final osmolarity of 230 mOsmol) was sufficient to completely stop the expulsion of the contractile vacuole. Immunofluorescence demonstrated that the blocking of fluid output was accompanied by the disappearance of most fluorescence labeling from the decorated spongiome (the A4 antigen). Electron microscopy revealed that the disappearance of the labeling was accompanied by the disappearance of the decorated tubules from around the collecting canals. These tubules vesiculate. The other membranes of the contractile vacuole complex remained unaffected which was demonstrated by both electron microscopy and indirect immunolabeling using the mAb against the G4 antigen. These results show that the decorated spongiome is formed from a distinct membrane pool separate from that of the smooth spongiome, collecting canals and the contractile vacuole. Recovery of the decorated spongiome rapidly followed the return of the cell to an isotonic environment and was completed within 3 hours. Decorated tubule recovery paralleled the recovery of the function of the contractile vacuole. Recovery was also observed during continuous hyperosmotic treatment with the reappearance of the contractile vacuole activity starting at 3 hours and stabilizing at around 10 hours of incubation. Functional recovery under these conditions was accompanied by a reappearance of the decorated tubules but the total fluid output was always lower than for cells in an isotonic environment. Thus, cells were shown to be capable of adapting to high hyperosmotic conditions. We conclude that the dissociation and reassociation of the decorated spongiome is an important regulatory feature controlling the activity of the contractile vacuole complex and of intracellular osmoregulation in Paramecium.

Adaptation, Physiological↗