Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 667 records · Page 37Linked to original sources

PubMed1996

A simple method for opening an obstructed peritoneal catheter using an infusion accelerator.

Catheter obstruction by a fibrin clot is one of the early complications after catheter implantation in continuous ambulatory peritoneal dialysis (CAPD) patients. manual compression of the dialysis solution container is usually the initial method used in an attempt to dislodge clots formed in the catheter. However, it is usually difficult to achieve and maintain sufficient pressure to open the obstructed catheter by this method. Alternatively, forceful irrigation using a syringe with heparin or urokinase, or clot removal using a corkscrew clot remover can be tried. These conventional maneuvers may potentiate the chances for bacterial contamination. In addition, these procedures require hospital visits by the patient. To solve this problem, we developed a new infusion accelerator for CAPD. Recanalization was attempted using the infusion accelerator in six cases of complete catheter obstruction. The bag was pressurized to 450 mm Hg. In all six cases, catheter patency was completely recovered without any complications. After appropriate training of patients, this method may be performed by patients themselves. Given the ease and efficiency of this procedure utilizing the improved equipment, we think that in cases with complete catheter obstruction this method should be considered before initiating more invasive procedures.

Adult↗

PubMed1996

Role of ICAM-1 and LFA-1 in endotoxin-induced uveitis in mice.

The effect of monoclonal antibodies against adhesion molecules on the development of endotoxin-induced uveitis (EIU) and interleukin-1 (IL-1)-enhanced EIU were studied. When endotoxin or IL-1 was injected into C3H/HeN mice, the expression of intercellular adhesion molecule-1 (ICAM-1) on the ciliary body was up-regulated as determined by immunohistochemical assay. However, these agents did not alter lymphocyte function-associated antigen-1 (LFA-1) expression on leukocytes when whole blood cells were analyzed with flow cytometry. Monoclonal anti-ICAM-1 antibody or anti-LFA-1 antibody was intraperitoneally administered to C3H/HeN mice simultaneously with endotoxin, and the effect on the development of EIU was studied. The cell number in aqueous humor and frequency of posterior synechiae were markedly decreased in EIU when either antibody was administered. However, protein concentration in the aqueous humor was not statistically reduced by the injection of these antibodies. In the model of IL-1 enhanced EIU, not only the cell number and frequency of posterior synechiae but also protein concentration were decreased. Moreover, there were no differences between these two antibodies in the effect on EIU, whereas anti-LFA-1 antibody was more effective than anti-ICAM-1 antibody in IL-1-enhanced EIU.

Animals↗

PubMed1996

[Lacunar brain infarction in patients with pseudoxanthoma elasticum].

Brain infarctions in patients with pseudoxanthoma elasticum (PXE) are thought to be associated with the damage of cerebral arteries injured by connective tissue change caused by PXE. We experienced 3 cases of PXE with lacunar brain infarction and evaluated the relationship between the damage of small penetrating arteries and PXE. All patients' diagnosis of PXE were confirmed by histological examination. They were a 47-year-old man and two women with 54 and 62 years of age old. All patients had pseudoxanthoma and angioid streaks and showed pyramidal tract signs. In addition, one patient presented Parkinsonism and another presented involuntary movement of the left lower extremities. None of these cases showed cortical symptoms. Brain CT and MRI revealed multiple lacuna in the areas of penetrating arteries, but their cerebral angiogram were almost normal. Severe small artery diseases, which cannot be attributable only to hypertension, were present. The relationship between such severe small artery disease and damage of the origin of small penetrating arteries caused by PXE was strongly suggested.

Dementia, Multi-Infarct↗

PubMed1996

Left ventricular cavitary geometry and dynamic intracavitary left ventricular obstruction during dobutamine stress echocardiography.

To investigate the relationship between left ventricular cavity geometry and dynamic intracavitary left ventricular obstruction occurring during dobutamine stress echocardiography, we evaluated 44 patients who underwent dobutamine stress echocardiography. Dynamic intracavitary left ventricular obstruction appeared in 10 (23%) patients (Group 1), and was absent in the remaining 34 patients (Group 2), during dobutamine stress echocardiography. The ratio of the apicalto-narrowest mid-left ventricular minor-axis dimension (D1/D2), as an index of the left ventricular cavitary geometry, was measured in the baseline two dimensional apical long-axis view. The left ventricular out-flow blood Doppler velocity was measured in the apical long-axis or five-chamber view at each stage during dobutamine infusion. Left ventricular end-systolic dimension was smaller (21 +/- 4 mm v 29 +/- 6 mm; p< .01), percent fractional shortening of the left ventricle was greater (51 +/- 4% v 39 +/- 8%, P>.01), and D1/D2 was greater (1.13 +/- 0.08 v.0.96 +/- 0.09; p < .0001) in Group 1 than in Group 2 in the baseline echocardiogram. Maximal out flow blood Doppler velocity during dobutamine infusion correlated moderately with percent fractional shortening of the left ventricle (r = .53; P < .01) and D1/D2 (r = .60; P < .0001). Dynamic intracavitary left ventricular obstruction, defined as an elevated intracavitary Doppler flow velocity with late-systolic peaking, was not related to the presence of left ventricular hypertrophy or the development of hypotension during dobutamine infusion. We conclude that dynamic left ventricular intracavitary obstruction during dobutamine infusion is associated with a characteristic (narrower-waisted) left ventricular cavitary geometry and increased contractility.

Adult↗

PubMed1996

The effect of postmortem interval on the concentrations of cocaine and cocaethylene in blood and tissues: an experiment using rats.

Cocaine and cocaethylene concentrations in blood and tissues at early stages postmortem (0-6 h) were investigated using alcohol-treated rats. Gas chromatography/mass spectrometry following a liquid/liquid extraction procedure was employed to detect these drugs. Calibration curves showed good linearity in the range of 0 to 2,500 ng/mL with correlation coefficients of 0.9999 and 0.9998 for cocaine and cocaethylene, respectively. In a group treated with cocaine and ethanol orally, the liver lost over 25% of the cocaine present at death after 1 h. Conversely, the hepatic cocaethylene concentrations at this time reached more than twice those at death. Thereafter, the hepatic concentrations of cocaine and cocaethylene were maintained at a constant level until 6 h postmortem. Similar results were obtained with rats given cocaine intramuscularly. No changes in the cocaine and cocaethylene concentrations in any other tissues during the 6-h of postmortem period were observed. The forensic pathologist and toxicologist should be aware of these phenomena when selecting postmortem specimens for the analysis of cocaine and cocaethylene and take them into account when interpreting the results.

Administration, Oral↗

PubMed1996

Controlling elements of platelet glycoprotein Ib alpha expression.

Our objectives are to define and characterize molecular events of megakaryocytopoiesis and platelet production by analyzing the in vivo expression of platelet glycoprotein (GP) receptors. Our studies target the platelet GP Ib-IX-V complex since the congenital absence of the receptor results in the Bernard-Soulier syndrome, a condition linking the expression of the complex to normal platelet morphogenesis. We have previously described the generation of a transgenic mouse colony expressing the alpha-subunit (GP Ib alpha) of the human platelet GP Ib-IX-V complex. These studies established methodologies to manipulate GP Ib-IX-V on the platelet surface and examine unique aspects of hemostasis, megakaryocytopoiesis, platelet structure and platelet release. Our recent studies have defined the genetic elements supporting the megakaryocytic-expression of GP Ib alpha. These results are defining essential cis-acting elements responsible for the expression of GP Ib alpha and are providing insights into molecular events coinciding with the release of normal platelets into the bloodstream.

Animals↗

PubMed1996

[Assessment of left ventricular contractility during intravenous induction of anesthesia by echocardiographic automated border detection].

A recently developed echocardiographic imaging system provides real-time automated border detection (ABD), which enables the measurement of cyclic changes in cavity area, and thus the calculation of changes in intracavity volumes. Eight patients (ASA 1-2) for non-cardiac surgery received thiopental (6 mg.kg-1) and succinylcholine (1 mg.kg-1) intravenously, and the trachea was intubated. The transthoracic echocardiography (TTE) was performed before induction. after induction, and after orotracheal intubation. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) were measured with ABD in apical four-chamber view. Mean arterial pressure (MAP) was measured simultaneously. MAP/ESV and MAP/SV were calculated as parameters of left ventricular contractility and left ventricular afterload, respectively. EF decreased significantly (P < 0.05) after induction (50.3 +/- 8.6%) compared with the value before induction (57.9 +/- 8.7%), and decreased further after intubation (41.7 +/- 10.6%). MAP/ESV also decreased significantly (P < 0.05) after induction (2.75 +/- 1.12 mmHg.ml-1) compared with the pre-induction value (3.81 +/- 1.73 mmHg.ml-1), and then returned to the pre-induction level after intubation (3.25 +/- 1.22 mmHg.ml-1). MAP/ SV showed no significant change during induction, and increased significantly (P < 0.05) after intubation (4.60 +/- 1.66 mmHg.ml-1) compared with pre-induction value (2.60 +/- 0.46 mmHg.ml-1). These findings suggest that the significant reduction in EF after induction of anesthesia was due to depression of cardiac contractility by thiopental, and that the further decrease after intubation was due to increase in afterload caused by the stimuli during intubation.

Adolescent↗

PubMed1996

[A case of central pain observed in medical medullary infarction].

A 45-year-old man had typical features of the left medial medullar syndrome which were left tongue paralysis, right hemiparesis, and right disturbance of touch and deep sensation sparing the face. He complained of hyperpathia, numbness and pain of the right body and limb sparing the face. MRI disclosed left upper medial medullary infarction, and cerebral angiography revealed occlusion of the left vertebral artery before the posterior inferior cerebellar artery. In general, the touch and deep sensation are carried through the medial lemniscus located in the medial medulla, therefore central pain is not considered to be induced by the medial medullary lesion. But tingling and numb sensation were sensory symptoms in our patient and the cases previously reported. If spinocervicothalamic tract related to touch and pain sensation has been well developed, it is suspected that central pain is induced by disturbance of the tract.

Cerebral Infarction↗

PubMed1996

[Cerebral infarction associated with meningitis].

Among 43 adult patients with meningitis, 8 (18.6%) had cerebral infarction associated with meningitis during their clinical course. The total number of cerebral infarctions was 18. In 4 patients of good outcome (ambulatory in 3 cases and wheelchair in 1 case) with a mean age of 39 years, the number of cerebral infarctions was 1 per patient, and did not increase. In 4 patients of poor outcome (vegetative in 2 cases and died in 2 cases) with a mean age of 68 years, the number of cerebral infarctions was 1 in two cases and 2 in two cases, and later increased in 3 of the cases. Locations of cerebral infarctions were 3 in the striatocapsular lesion, 1 in the posterior limb of internal capsule, 1 in the middle cerebral artery territory, 5 in the tuberothalamic artery territory, 5 in the capsular genu, 1 in the posterior choroidal artery territory, and 2 in the medial striate artery territory. Patients of poor outcome had capsular genu infarction. It was concluded that multiplicity and multiplication of cerebral infarction were markers of the severity of the meningitis.

Adult↗

PubMed1996

[The intravascular mobile structure detected by duplex carotid ultrasonography in cardioembolic internal carotid artery occlusion].

We reported that duplex carotid ultrasonography demonstrated specific mobile intravascular mass in four patients with cardiac cerebral embolism. In all cases, duplex carotid ultrasonography clearly showed the presence of a mobile intravascular mass in the carotid artery within 2 days after the onset. In two of four cases, the follow-up duplex carotid ultrasonography showed disappearance of the previously observed "a mobile intravascular mass" 7 days after the onset. In the other two cases, a mobile intravascular mass became stable gradually and changed to non-mobile hyperechoic mass 10 days after the onset. We think that the intravascular mobile structure was probably a thrombus extending from the occlusive part of the internal carotid artery to the proximal side. We suspect that the specific "a mobile intravascular mass" detected by ultrasonography may help to diagnose embolic internal carotid artery occlusion.

Aged↗

PubMed1996

[A case of bilateral infarction of medial pontomedullary junction].

A 69-year-old man suffered from dizziness and nausea after work, and was admitted to our hospital on the next day. On admission, he showed bilateral horizontal nystagmus and left hemiparesis. On the 3rd day he vomited frequently, and the dizziness became worse. Bilateral horizontal and upward gaze palsy and bilateral facial nerve palsy were observed. Brain MRI on the 5th day disclosed bilateral upper medial medullary infarction that extended to the pontomedullary junction. Cerebral angiography on the 13th day revealed occlusion of the right vertebral artery. This case did not show typical medial medullary syndrome. The mechanism was unknown, but similar cases were reported. Recently, many cases of medullary infarction are reported with the progress of MRI technology. It is suggested that the addition of the new concepts on the conventional syndromes of medullary infarction is necessary.

Aged↗

PubMed1996

Changes of expression of complement 3bi receptors on granulocytes after physical exercise in rats.

OBJECTIVE: The purpose of this study was to examine the effects of physical exercise on the expression of clusters of differentiation (CD)11b, CD18 and CD 54 on granulocytes and complement 3bi (C3bi)-dependent functions in rats. EXPERIMENTAL DESIGN: The rats were separated into two groups: the control group (n = 21) and the training group (n = 14). The rats in the training group were subjected to a program that consisted of swimming 6 days in a week for 7 weeks. MEASURES: The phagocytic and hydrogen peroxide (H2O2) generating activities and the expression of receptors on granulocytes were measured using flow cytometric techniques. RESULTS: The acute swimming and the 7 weeks of swim training caused high C3bi-dependent phagocytic activity of granulocytes. Swim training led to an increase of H2O2 generating activity together with C3bi-dependent phagocytosis both immediately after and 24 hrs after the 120 min swimming. The 24 hrs recovery from the 120 min swimming in trained and untrained rats caused an increase of H2O2 generating activity of granulocytes. In the training group, an increase in this activity could be observed immediately after the 120 min swimming exercise. The upregulation of the CI1b on granulocytes was induced by the 120 min of swimming regardless of swim training. CONCLUSIONS: These results suggest that the increase of C3bi receptor-dependent phagocytosis and H2O2 generating activities induced by the physical exercise might depend on the upregulation of the CD11b that is the component of C3bi receptor.

Animals↗

PubMed1996

A brief overview of apoptosis.

Apoptosis, a characteristic type of cell death, plays important roles in tissue and organ development in ontogeny. It also relates to the occurrence of serious diseases such as virus infection, autoimmune disease and cancer. Furthermore many drugs such as anticancer agents express their cytotoxicity via induction of apoptosis in the target cells. This article summarize the recent studies on apoptosis in view of its molecular mechanism and the relation to diseases.

Apoptosis↗

PubMed1995

Effects of cocaine administration route on the formation of cocaethylene in drinkers: an experiment using rats.

The effects of cocaine administration route on the formation of cocaethylene, an active metabolite of cocaine produced in the presence of ethanol, were investigated using rats. When 20 mg/kg cocaine was administered into the stomach together with 2 g/kg ethanol, maximum liver concentrations of cocaine and cocaethylene, 8410 +/- 3600 and 1680 +/- 520 ng/g, respectively, were observed at 15 min. In other tissues the maximum levels of both the substances were attained in 30 min, but were much lower than those in the liver. Intramuscular administration of 20 mg/kg cocaine with 2 g/kg oral ethanol gave levels of liver cocaine as low as 103 +/- 29 to 150 +/- 35 ng/g, resulting in no detection of liver cocaethylene over the entire 180-min study period, although gradual accumulation of cocaethylene was observed in other tissues. The accumulation patterns of cocaine and cocaethylene in blood of alcohol-intoxicated rats after the i.m. administration of cocaine were similar to those in blood of drinkers after nasal insufflation of cocaine. Despite i.v. administration of 1 mg/kg cocaine with 2 g/kg oral ethanol, no detectable amounts of cocaethylene appeared in any tissues over the entire 60-min study period. The present findings are considered to be of importance in the fields of forensic and clinical toxicology for clarifying (1) the rate of in vivo cocaethylene formation and (2) the distribution of cocaine and cocaethylene in blood and tissues.

Alcoholic Intoxication↗

PubMed1995

Primary structure of a gamma subunit of G protein, gamma 12, and its phosphorylation by protein kinase C.

We have determined the primary structure of a novel gamma subunit (gamma 12, previously designated gamma S1) of G protein purified from bovine spleen. The mature gamma 12 protein composed of 68 amino acids had acetylated serine at the N terminus and geranylgeranylated/carboxylmethylated cysteine at the C terminus. This was consistent with the C-terminal prenylation signal in the amino acid sequence, which was predicted from gamma 12 cDNA isolated from a bovine spleen cDNA library. Western blots with the specific antibody against gamma 12 showed that gamma 12 is present in all tissues examined. Among various gamma subunits (gamma 1, gamma 2, gamma 3, gamma 7, and gamma 12), gamma 12 has a unique property to be phosphorylated by protein kinase C. The phosphorylated amino acid residue was Ser1 (or Ser2). The phosphorylated beta gamma 12 associated with Go alpha more tightly than the unphosphorylated form. Exposure of Swiss 3T3 and aortic smooth muscle cells to phorbol 12-myristate 13-acetate and NaF induced phosphorylation of gamma 12. Stimulation of aortic smooth muscle cells with natural vasoactive agents such as angiotensin II and vasopressin also induced phosphorylation of gamma 12. The extent of phosphorylation of beta gamma 12 in vitro was suppressed by a complex formation with Go alpha, which was relieved by the addition of guanosine 5'-O-(3-thiotriphosphate) or aluminum fluoride. These results strongly suggest that gamma 12 is phosphorylated by protein kinase C during activation of receptor(s) and G protein(s) in living cells.

Amino Acid Sequence↗

PubMed1995

Identification of a major cytokinin in coconut milk.

A major cytokinin found in coconut milk was isolated by using the tobacco callus growth-promoting assay as a guide during purification. The structure of the factor was determined to be 14-O-(3-O-[beta-D-galactopyranosyl-(1-->2)-alpha-D-galactopyranosyl-(1-- >3)- alpha-L-arabinofuranosyl]-4-O-(alpha-L-arabinofuranosyl)-beta-D- galactopyranosyl)-trans-zeatin riboside [G3A2-ZR] by various NMR techniques, including heteronuclear multiple bond connectivity by 2D multiple quantum NMR (HMBC), as well as mass spectroscopy and sugar analysis. The optimum concentration of G3A2-ZR for cytokinin activity in the tobacco callus assay was estimated to be 5 x 10(-6) M, so that G3A2-ZR is one order of magnitude more potent than 1,3-diphenylurea and one order less potent than zeatin riboside. At least 20% of the cytokinin activity of coconut milk could be attributed to G3A2-ZR.

Carbohydrate Conformation↗

PubMed1995

Analysis of CD2 and TCR-beta gene expression in Jurkat cell mutants suggests a cis regulation of gene transcription.

Thirty CD2- J32 stable clones, derived by mutagenesis and subsequent immunoselection with anti-CD2 Ab, were used to study the regulation of CD2 and TCR gene expression. Analysis of RNA expression revealed that the loss of surface expression of CD2 was due to a lack of expression of CD2 mRNA and was associated with a lack of expression of VDJ TCR-beta transcripts in 12 of these mutants, sparing the expression of DJ TCR-beta, TCR-alpha, CD3 gamma, delta, epsilon, and zeta RNA. The expression of other differentiation molecules was unaffected, except for CD1, CD4, and CD5, which were either decreased or absent in most of these mutants. A gain in the expression of TCR-gamma transcripts was observed in each of these mutants, while, as expected, no TCR-gamma transcripts were detected in wild-type J32 cells. Several mutants were able to use the human CD2 enhancer and the murine TCR-beta enhancer and promoter to activate transcription from reporter genes in the context of heterologous promoters, indicating that the mutation(s) does not affect transcription pathways. Consistent with this finding is the adequate expression in these mutants of several lineage-specific transcription factors. The expression of CD2 in several of these mutants was rescued by gene transfer using a genomic 28.5-kb CD2 fragment, suggesting that the enhancer function of this gene may be dependent on the enhancer site. These observations suggest that the coordinate expressions of CD2 and TCR-beta genes share common regulatory mechanisms involving factors regulating chromatin structure and accessibility.

Antigenic Variation↗

PubMed1995

Identification of essential GATA and Ets binding motifs within the promoter of the platelet glycoprotein Ib alpha gene.

Platelet glycoprotein (GP) Ib-IX-V is a multisubunit adhesion receptor that supports platelet attachment to thrombogenic surfaces at sites of vascular injury. The congenital absence of the receptor results in a bleeding disorder associated with "giant" platelets, a condition linking the expression of the complex to platelet morphogenesis. To understand better the expression of the GP Ib-IX-V complex, studies were undertaken to define the essential genetic elements supporting the expression of the alpha-subunit of the complex (GP Ib alpha). GP Ib alpha promoter activity was evaluated by transfection of human erythroleukemia cells with reporter plasmids coding for the enzyme, luciferase. Studies were initiated with a fragment extending 2,738 nucleotides 5' to the transcription start site and lead to the identification of 253 nucleotides retaining full promoter activity in human erythroleukemia cells. In cells of nonhematopoietic lineage, human endothelial and HeLa cells, the GP Ib alpha promoter activity was no greater than background levels obtained with promoterless constructs. Gel shift assays and site-directed mutagenesis studies defined essential GATA and Ets binding motifs 93 and 150 nucleotides upstream of the transcription start site, a finding which further substantiates these elements as important determinants of megakaryocytic gene expression. The results define essential cis-acting elements responsible for the expression of GP Ib alpha and provide insights into molecular events coinciding with the release of normal platelets into the bloodstream.

Base Sequence↗