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Biomedical subjects

K Sakai

Publications and source records attributed to K Sakai.

At least 613 records · Page 34Linked to original sources
PubMed1995

Gq/11 communicates with thromboxane A2 receptors in human astrocytoma cells, rabbit astrocytes and human platelets.

Western blot analysis was performed to clarify the presence of trimeric G protein subfamily in membranes derived from human astrocytoma cells (1321N1), cultured rabbit astrocytes and human platelets, using G protein antisera GS alpha, Gi alpha, Gq/11 alpha, and G beta were found to exist in membranes derived from human astrocytoma cells and rabbit astrocytes as well as human platelets. However, only small amount of G(o) alpha was detected in any membranes. Gq/11 alpha was expressed much more in human platelets than in human astrocytoma cells or rabbit astrocytes. 9,11-Epithio-11,12-methanothromboxane A2 (STA2), a stable analogue of thromboxane A2 (TXA2), activated GTPase in membranes derived from human astrocytoma cells, rabbit astrocytes and human platelets with different potencies. STA2-induced GTPase activation in human platelet membranes was partly inhibited by treatment with QL antibody at 0 degrees C for 90 min. Furthermore, STA2-induced GTPase activation in membranes derived from human astrocytoma cells and rabbit astrocytes were potently inhibited by treatment with QL antibody. The results obtained indicate that TXA2 receptors in human astrocytoma cells and rabbit astrocytes communicate with Gq/11 as well as in human platelets.

Animals↗
PubMed1995

[A case of critical illness polyneuropathy in association with peritonitis after sigmoid colon perforation].

We presented a case of critical illness polyneuropathy after bacterial peritonitis. A 62-year-old male was received an emergency colectomy because of perforation of the sigmoid colon five days after the endoscopic polypectomy. He developed sepsis from peritonitis after operation in spite of the antibiotics therapy. On 15-th hospital days he developed muscle weakness and numbness of all limbs. He needed an artificial ventilator due to respiratory failure. Hematological and blood chemical findings showed a leukocytosis and metabolic acidosis with renal dysfunction because of sepsis. Serum anti-Campylobacter antibody was negative. Serial CSF examinations failed to show any abnormalities including albuminocytologic dissociation. Electrophysiological studies revealed a primary axonal degeneration, mainly in the motor, but also in the sensory nerve. Compound muscle and sensory action potentials were not elicited or markedly reduced without conduction velocity prolongation. Microscopic findings of the left sural nerve biopsy showed a primary axonal degeneration without evidence of inflammation. His prognosis was poor and three months later, he still required ventilatory assistance. Because of these clinical findings this patient was thought to have a critical illness polyneuropathy after excluding various etiologies of polyneuropathies. This case suggests that sepsis may be one of a cause of primary axonal polyneuropathy. The certain mechanism of this disease is still unknown. However cytokine, tumor necrotic factor(TNF) and/or Platelet activating factor(PAF) that secreted during sepsis may have an important role for the primary axonal degeneration.

Critical Illness↗
PubMed1995

[Clinical significance of transesophageal echocardiography for evaluation of patients after Bentall's operation: detection of graft failure].

Leakage from the composite graft at the site of coronary anastomosis into the perigraftal space (pseudoaneurysm) is an important complication of Bentall's operation. The clinical value of transesophageal echocardiography (TEE) for detecting this graft failure was evaluated in 30 patients who underwent Bentall's operation or Piehler's modification. Three patients (10%) had perigraftal leakage (pseudoaneurysm). TEE demonstrated the leakage site which was not clearly showed by computed tomography (CT) scan and aortography. The detection rate of the anastomosed native coronary artery was 89% (left: 100%, right: 67%). Interposition graft by Pichler's modification method was detected in 96% (left: 100%, right: 92%) of cases by TEE, but only in 43% (left: 57%, right: 29%) by CT scan (left: p < 0.005, right: p < 0.0001). The detection rate of the right coronary artery, interposition graft to right coronary artery, and their color signals were lower than those of the left coronary artery. TEE has considerable diagnostic value in evaluating patients after Bentall's operation.

Adult↗
PubMed1995

[A fundamental study of 99mTc-HMPAO double injection method and clinical application to stress scintigraphy in orthostatic hypotension].

Double injection method using brain perfusion 99mTc-HMPAO SPECT is popular one for evaluating stress scintigraphy. For appropriate evaluation of this method 555 MBq (15 mCi) of 99mTc-HMPAO was injected twice in sequence at the resting state. The first and second SPECT images were obtained 5 min after each injection. Twenty-five ROIs of 8 x 8 pixels were placed on in various regions of the first images, and calculate each counts (C1). Then the counts of the same region of the second scan were calculated (C2). One hundred and fifty ROIs/6 patients were examined. We derived the linear relationship as C2 = 1.66 x C1 + 106 (r = 0.97), where C1 and C2 represents counts of the first scan, and second scan, respectively. This results suggests that the counts of the second scan is derived from the counts of the first scan without second scanning if they are obtained in the same condition. When we applied this method to stress scintigraphy, it may be useful for evaluating the regional brain perfusion changes before and after loading instead of using subtraction technique.

Aged↗
PubMed1995

[A strong predictor of breast cancer--hepatocyte growth factor (HGF)].

We measured the hepatocyte growth factor (HGF) concentration in breast cancer tissue extracts and evaluated its association with survival. The HGF level was found to be the most important factor in survival, even more so than lymph node involvement. HGF may play an important role in the progression of human breast cancer.

Breast Neoplasms↗
PubMed1995

[Change in the treatment procedures for mitral valve disease].

This study investigated the changes in treatment procedures for mitral stenosis (MS) and mitral regurgitation (MR) against the background of a decrease in the incidence of rheumatic valvular disease. The study included 3,955 patients with MS undergoing closed mitral commissurotomy (CMC), open mitral commissurotomy (OMC), mitral valve replacement (MVR), or percutaneous transvenous mitral commissurotomy (PTMC) between 1952 and 1991, and 478 patients with MR undergoing MVR or mitral valvuloplasty in the Heart Institute of Japan, Tokyo Women's Medical College. The number of patients with MS undergoing surgical or catheter interventions has decreased and is now about 80 per year, a half of that experienced in the 1960s. CMC and OMC have been replaced by PTMC since the 1990s. The most popular treatment procedure is now MVR. The number of patients with MR undergoing surgery has increased to about 30 per year. Eighty percent of operations for MR are MVR and the others are mitral valvoplasty. Survey of the etiology of MR shows decreased rheumatic disease and increased degenerative disease. The incidence of MR due to ischemic heart disease and hypertrophic obstructive cardiomyopathy has slightly increased.

Adolescent↗
PubMed1995

[Chronic pancreatitis and pancreatic dysfunction associated with Sjögren's syndrome].

Some pancreatic involvement was observed in Sjögren's syndrome (SS). Episodes of abdominal pain occurred infrequently in the course of SS, but there were some abnormal findings of the pancreatic functions and/or morphologic examinations. The level of serum amylase was affected by the destruction of both the pancreas and the salivary gland. Hyposecretion of bicarbonate in secretin test seemed to be characteristic in SS. ERP showed mild or moderate changes of the pancreatic duct, but their severities did not correlate with those of the salivary gland. Imaging of the pancreas tended to reveal definite abnormalities only in cases with an attack of pancreatitis. The roles of autoimmune mechanisms have been reported in pancreatitis associated with SS.

Amylases↗
PubMed1994

Phenotypic changes of AADC-only immunopositive premammillary neurons in the brain of laboratory shrew Suncus murinus by systemic administration of monoamine precursors.

After 5-hydroxy-L-tryptophan (5-HTP) and L-3,4-dihydroxyphenylalanine (L-DOPA) were injected i.p. in the laboratory shrew Suncus murinus, immunocytochemical and immunofluorescence studies were conducted on continuous or same sections of the brain, using specific anti-tyrosine hydroxylase (TH), anti-aromatic L-amino acid decarboxylase (AADC), anti-dopamine (DA) and anti-serotonin (5-HT) antisera which were produced in our laboratory. The results of double-staining by the immunofluorescence method as well as immunoelectron microscopy strongly indicate that the cells of the premammillary nucleus of the laboratory shrew brain (AADC-only-positive neurons) are capable of synthesizing DA and 5-HT simultaneously upon simultaneous administration of L-dopa and 5-HTP.

Animals↗
PubMed1994

Eye saccade dynamics during paradoxical sleep in the cat.

Cat eye movements were recorded during wakefulness and paradoxical sleep with the technique of the scleral search coil in a magnetic field. During waking, eye movements consisted of a succession of saccades and fixation phases. During paradoxical sleep, the pattern of eye movements displayed drifts of variable velocity and direction and short fixation phases, upon which saccades superimposed. These saccades displayed a repetitive, stereotyped, asymmetrical pattern. The maximum velocity/amplitude relationships, i.e. the main sequences, were determined for spontaneous and visually induced saccades of waking and for the following types of saccades during paradoxical sleep: (i) isolated saccades accompanied by ponto-geniculo-occipital (PGO) waves, (ii) isolated saccades accompanied by eye movement potentials (EMP), and (iii) saccades in bursts accompanied by PGO waves. The slope of the main sequence relationship of any type of paradoxical sleep saccade (from 21.7 degrees/s/degree for isolated saccades to 35.6 degrees/s/degree for saccades in bursts) was higher than that of any type of waking saccade (11.2 degrees/s/degree for spontaneous saccades to 14.7 degrees/s/degree for visually elicited ones). Furthermore, during paradoxical sleep, saccades in bursts were faster than isolated ones. This demonstrates that different neurophysiological mechanisms subserve the generation of waking saccades, paradoxical sleep isolated saccades and paradoxical sleep saccades in bursts, or that the oculomotor system is in a different state of excitation during these different sets of saccades. These findings throw new light on the functioning of the oculomotor system during paradoxical sleep and are discussed in terms of the functional significance of paradoxical sleep saccades and PGO waves.

Animals↗
PubMed1994

Purification and characterization of a protein-tyrosine kinase p72syk from porcine spleen.

We have succeeded in purifying p72syk, a non-receptor-type protein-tyrosine kinase carrying high susceptibility to proteolysis [Taniguchi, T., Kobayashi, T., Kondo, J., Takahashi, K., Nakamura, H., Suzuki, J., Nagai, K., Yamada, T., Nakamura, S. and Yamamura, H. (1991) J. Biol. Chem. 266, 15790-15796] from porcine spleen. The purification procedure involves a sequential column chromatography, following extraction with 0.5 M NaCl from spleen homogenate, on phosphocellulose, Sephacryl S-200, heparin-Sepharose CL-6B, Mono Q and Mono S. SDS/PAGE of the final purified sample revealed a 72-kDa protein band with about 95% purity and immunodepletion analysis showed immunological cross-reactivity with anti-p72syk antibody which does not recognize ZAP-70. It was purified approximately 3000-fold with an overall yield of 0.54% according to [Val5]angiotensin II phosphorylation activity and the specific activity of the final sample (30 nmol phosphate.min-1.mg protein-1) was relatively lower than that of the 40-kDa kinase, a catalytic fragment of p72syk which lacks two src homology regions 2 domains. The p72syk had an autophosphorylation activity that was performed by intramolecular catalysis accompanied by a phosphate exchange reaction, and could efficiently phosphorylate tubulin, myelin basic protein and H2B histone. Employing [Val5]angiotensin II as a substrate, the apparent Km value for the peptide was 0.91 mM and that for ATP was 0.48 microM. Mn2+, Mg2+ and Co2+ were effective divalent cations and optimum pH was around 8.0-8.5 for the expression of the activity. These results suggest that the purified p72syk may exist as a less active form compared with the 40-kDa kinase and that the part of p72syk containing two src homology region 2 domains may participate in the regulation of its activity though the enzymic character is quite similar to that of the 40-kDa kinase.

Amino Acids↗
PubMed1994

Asbestos and nonasbestos fiber content in lung tissue of Japanese patients with malignant mesothelioma.

BACKGROUND: Pulmonary fiber content of both asbestos and nonasbestos types were evaluated in Japanese patients with malignant pleural mesotheliomas. METHODS: Pulmonary fiber content was analyzed in 16 patients and 16 case-matched control subjects by transmission electron microscopy with energy-dispersive X-ray analysis using a low-temperature ashing procedure. RESULTS: The geometric mean content of total asbestos was significantly higher in the patients (22.0 x 10(6) fibers/g dry lung) than in the control subjects (2.24 x 10(6) fibers/g dry lung) (P < 0.01). When the asbestos content was analyzed by fiber type, the geometric means were also consistently and significantly higher among the patients compared with the control subjects (P < 0.01). Results were as follows: (1) amosite: patients 3.94 times 10(6) versus control subjects 0.23 x 10(6); (2) crocidolite: patients 3.56 times 10(6) versus control subjects 0.35 times 10(6); (3) total amphiboles: patients 16.0 times 10(6) versus control subjects 0.77 times 10(6); and (4) chrysotile: patients 3.76 times 10(6) versus control subjects 1.01 times 10(6). However, when individual total asbestos content was considered, 7 of the 16 patients (44%) had levels lower than the highest value noted among the control subjects. Pulmonary fiber content of patients and control subjects also revealed the presence of nonasbestos fibers. The geometric mean of nonasbestos fibers was significantly higher in the patients (87.3 x 10(6)) than in control subjects (33.8 x 10(6)) (P < 0.01). The major type of nonasbestos fibers in both groups was aluminum silicates. The mean of ratios of nonasbestos fiber contents to total asbestos contents in the patients and control subjects was 7.0 and 17.3, respectively. CONCLUSIONS: The results were mainly in agreement with the findings of earlier investigations, but fiber content of both chrysotile and nonasbestos fiber as well as those of amphibole asbestos were significantly higher in the patients than in the control subjects.

Adult↗
PubMed1994

Hypothalamo-preoptic histaminergic projections in sleep-wake control in the cat.

Cats were chronically implanted with electrodes for polygraphic recordings and cannulae for intracerebral microinjections in order to study the functional role of histaminergic innervation of the preoptic-anterior hypothalamus in sleep-wake control. alpha-Fluoromethylhistidine (alpha FMH, 50 micrograms in 1 microliter), a specific inhibitor of the histamine-synthesizing enzyme, when injected bilaterally into the preoptic area, where numerous histaminergic fibres and terminal-like structures are present, caused a significant increase in deep slow wave sleep (S2) and paradoxical sleep (PS) and a decrease in wakefulness. In contrast, microinjections of histamine (5 or 30 micrograms in 1 microliter) in the same area dose-relatedly increased wakefulness and decreased both slow wave sleep and paradoxical sleep. The effects of histamine were reduced by pretreatment with mepyramine (1 mg/kg i.p.), a well known histamine H1 receptor antagonist, and were mimicked by a local injection of impromidine (1 microgram in 1 microliter), a potent histamine H2 receptor agonist. Microinjections of mepyramine alone (120 micrograms in 1 microliter) caused an increase in slow wave sleep. These results suggest that preoptic histaminergic innervation is involved in sleep-wake control and that the action might be mediated via both H1 and H2 receptors.

Animals↗
PubMed1994

A hippocampal protein associated with paraneoplastic neurologic syndrome and small cell lung carcinoma.

A hippocampal 38 kd autoantigen recognized by an autoantibody from the serum of a patient with paraneoplastic limbic encephalitis (PLE) and small cell lung carcinoma (SCLC) was isolated by screening a human hippocampal cDNA library. The 1,991-nucleotide ple21 clone was obtained and the deduced 350-residue protein encoded by the ple21 cDNA clone was found to be highly homologous to the neuron-specific RNA recognition motifs (RRMs)-containing proteins. The homologies were confined to the RRMs and the RRM connecting region. The presence of RRM in the antigenic protein may be important in the pathogenesis of SCLC-associated paraneoplastic neurologic syndrome.

Amino Acid Sequence↗
PubMed1994

Neuronal tuning to learned complex forms in vision.

We tested the hypothesis that the fine form selectivity of anterior inferotemporal (AIT) neurones represents long-term memory of object forms. Prior to neuronal recording, two monkeys were trained to learn a set of computer-generated Fourier descriptors (FDs). A slight alteration of one FD parameter produces a form with similar global features. We found that these altered forms always elicited weaker neuronal responses than the learned forms. This effect was not due to nonsensory factors such as attention, because another sham manipulation, in which one FD was rotated or reflected, did not produce a comparable effect. These results demonstrate that AIT neurones acquire a preference for complex forms through learning by tuning mechanisms.

Animals↗
PubMed1994

Calcification in carcinoma of the stomach: report of a case.

By upper gastrointestinal series, a 57 years-old woman was pointed out to have scattered calcifications along the greater curvature of the stomach. On computerized tomography, the calcifications distributed in the irregularly thickened gastric wall. With a diagnosis of calcified mucinous adenocarcinoma showing Borrmann type III, total gastrectomy with splenectomy was carried out. The characteristics of this lesion were briefly presented with a review of the literature.

Adenocarcinoma, Mucinous↗
PubMed1994

Chromaffin cells express Alzheimer amyloid precursor protein in the same manner as brain cells.

Amyloid precursor protein (APP) 695 is remarkably expressed in the brain as compared with APP751 and APP770 which are dominant in other tissues. This study showed that human and bovine adrenal medullae dominantly expressed mRNA of APP695 as do brain nerve cells, while the adrenal cortexes expressed mRNAs of APP751 and APP770 as in other non-neural tissues. In immunohistochemistry, chromaffin cells of young rat adrenal medullae and primary cultured bovine chromaffin cells were significantly stained with a monoclonal antibody (mAb) against the common domain of the amino-terminal side of human APPs. At higher magnification, the immunostained cells revealed that APP was granularly distributed not only in the perikaryon but also in the cell processes. These results suggest that primary cultured chromaffin cells representing the state of adrenal medulla in vivo are a useful model for studying the pathophysiological functions of APPs and the mechanism of processing of APPs as a model of neuronal systems.

Adrenal Cortex↗