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Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 289 records · Page 16Linked to original sources
PubMed1995

[Rheumatoid factor and cryoglobulin are not efficiently related to cold activation of complement].

Cold activation of complement (CA) is a phenomenon characterized by a low hemolytic complement activity in chilled serum. Cryoglobulin and RF have been reported as main causes of CA, and we previously reported the close association between CA and HCV infection in 21 CA patients. Therefore, we assayed CA, RF, cryoglobulin and anti-HCV antibody titers in 304 randomly selected patients with unknown diseases. CA was positive in 26 of the 304 patients, and among them, RF and/or cryoglobulin were found positive in 20 patients, and anti-HCV antibody were positive in all of them. RF was positive in 41 of the 304 patients. 37% of them were anti-HCV antibody positive and 63% were negative. Cryoglobulin was positive in 61 out of 304 patients. Anti-HCV antibody positivity was observed in 59 out of 304 patients, and all CA-positive cases were included in the anti-HCV antibody-titer-positive group. However, either RF or cryoglobulin positive patients were observed in the same degree in both anti-HCV antibody titer positive and negative groups. Therefore, RF or cryoglobulin is not considered the main cause of CA.

Cold Temperature↗
PubMed1995

[Applications of mass spectrometry for clinical laboratory test].

Mass spectrometry (MS) has recently played a considerable role in the chemical measurements in clinical laboratories. We have analyzed organic acids for diagnosis of organic acidemias, and tried to report quantitative data measured by GC/MS with 20 kinds of standard compounds of key metabolites labelled with stable isotopes. By ESI/MS/MS acylcarnitine was analyzed accurately and quickly. We found a new acylcarnitine compound in urine from a patient with multiple carboxylase deficiency, which showed m/z 276 ion peak on the spectrum by precursor ion scan of methylated compounds of dried raw urine. This was identified as 3-hydroxyisovalerylcarnitine. By ESI/MS, hemolysate was analyzed and an ion peak of abnormal alpha subunit of hemoglobulin, Hb MBoston, was clearly separated from the normal alpha subunit. Serum transferrin precipitated with anti-transferrin serum was analyzed by MALDI/TOF/MS. The transferrin-antibody complex in the immunoprecipitates was separated into transferrin and IgG in an acidic pH, which is the usual condition of loading on MALDI/TOF/MS. Ions of IgG and other minor components were not superimposed on the transferrin ions. Transferrin isoform with a molecular weight about 2.2kDa smaller than normal transferrin, which is contained in the serum from patients with carbohydrate-deficient glycoprotein syndrome, was identified by this method. The MALDI/TOF/MS analysis of immunoprecipitates may serve as a simple and sensitive method to identify the molecular weight heterogeneity of various biological materials.

Carnitine↗
PubMed1995

[A case of testicular tumor associated with the contralateral undescended testis].

A 36-year-old man visited the hospital complaining of painless swelling of the right scrotal contents. His left scrotal contents were absent in the scrotum. Right inguinal orchiectomy was performed on May 17, 1993 under the diagnosis of testicular tumor. The pathological diagnosis of the tumor was pure seminoma. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) revealed the enlargement of para-aortic lymph nodes and there was a soft tissue signal in the left inguinal region which seemed to be the left testis in MRI. His serum testosterone level was low and gonadotropin level was high. The left orchiopexy was performed on June 24, 1993, but the left testis was finally removed because of methicillin-resistant Staphylococcus aureus (MRSA) infections. Radiation therapy was done against the metastatic lesion in the retroperitoneal lymph nodes and complete remission was obtained. The left undescended testis pathologically showed atrophy of germ cells but there was no appearance of atypia of Leydig cells or germ cells.

Adult↗
PubMed1994

The functions of the ninth component of human complement are sustained by disulfide bonds with different susceptibilities to reduction.

Purified C9 with expected hemolytic and polymerizing activities was found to contain approximately 0.2 mol of sulfhydryl groups/mol of C9. By proteolysis of C9 with labeled SH groups, the SH residues on intact C9 were mapped to Cys-359 and Cys-384 which, presumably, form an intra-domain disulfide bond in the intact molecule. The blocking of these sulfhydryl residues by alkylation, however, had minimal influence on the functions of C9. On the other hand, reduction of C9 by 1 mM dithiothreitol (DTT) (6-fold molar excess over Cys residues) followed by alkylation resulted in a complete block of polymerization activity and a 50% loss of C9 hemolytic activity. In contrast, the ability of C9 to bind EAC1-8 remained largely unaffected. The loss of poly-C9 formation activity correlated with the alkylation of approx. 6 liberated sulfhydryl groups. Hemolytic activity was abolished by treatment with > 5 mM DTT which allowed the liberation of approximately 18 sulfhydryl groups. Most of the DTT-susceptible disulfides were within the C9a fragment (an N-terminal peptide derived by thrombin). Thus, three major functions of C9, EAC1-8 binding, polymerization, and hemolytic activity, are sustained by disulfide bond-dependent conformational motifs with different susceptibility to reducing reagents. The maintenance of the N-terminal C9a region is essential for polymerization, but not EAC1-8 binding activity of C9. Taken together, the results of the present study differentiate in molecular terms several of the functional portions of C9, and stress the significance of intra-chain disulfide linkages in maintaining the structural components necessary for the functions of C9.

Animals↗
PubMed1994

Significance of hepatocellular proliferation in the development of hepatocellular carcinoma from anti-hepatitis C virus-positive cirrhotic patients.

BACKGROUND: There is a hypothesis explaining the pathogenesis of carcinoma that increased proliferation of tissue cells correlates with the development of carcinoma, presumably by increased rate of random mutations and by promotion. In this study, the significance of hepatocellular proliferation in the development of human hepatocellular carcinoma (HCC) from anti-hepatitis C virus (HCV)-positive cirrhotic patients was studied. METHODS: Twenty-eight Child A cirrhotic patients who were anti-HCV (C-100 antibody) positive were studied. At the beginning of the study, the in vitro uptake of bromodeoxyuridine (BrdU, a thymidine analogue) by hepatocytes in biopsied liver specimens was investigated as labeling indices (LIs), and they were divided into high-DNA synthetic (BrdU LI > or = 1.5%) and low-DNA synthetic (BrdU LI < 1.5%) groups. The patients were then surveyed prospectively with frequent ultrasonography (every 3 months) for the development of HCC for 3 years. RESULTS: The mean BrdU LI plus or minus standard deviation for 14 cirrhotic patients with high-DNA synthesis activity (BrdU LI > or = 1.5%) was 2.7 +/- 0.8%, and this was significantly (P < 0.001) higher than that for 14 cirrhotic patients with low-DNA synthesis activity (BrdU LI < 1.5%, 0.5 +/- 0.3%). Nine of 14 (64.3%) of the cirrhotic patients with high-DNA synthesis activity developed HCC in the 3-year period, in contrast to only 2 of 14 (14.3%) of the cirrhotic patients with low-DNA synthesis activity P < 0.05).

Aged↗
PubMed1994

Laser desorption time-of-flight mass spectrometric analysis of transferrin precipitated with antiserum: a unique simple method to identify molecular weight variants.

Serum transferrin precipitated with anti-transferrin serum was analysed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS). The transferrin-antibody complex in the immunoprecipitates was separated into transferrin and IgG in an acidic pH, which is the usual condition of loading on MALDI-TOFMS. Ions of IgG and other minor components were not superimposed on the transferrin ions. Transferrin isoforms with different carbohydrate contents could be identified by this simple method easier than by affinity chromatography requiring the time-consuming preparation of an insolubilized specific antibody. The transferrin isoform with a molecular weight of approximately 2.2 kDa smaller than normal transferrin, which is contained in the serum from patients with carbohydrate-deficient glycoprotein (CDG) syndrome, was identified by this method. In addition to the M(1+) ion detected using sinapinic acid as a matrix, the M(2+) and M(3+) ions of transferrin were clearly detected using alpha-cyano-4-hydroxycinnamic acid as matrix and the molecular weight heterogeneity was identified more clearly in multivalent ions than that in the M(1+) ion. The MALDI-TOF analysis of immunoprecipitates may serve as a simple and sensitive method to identify the molecular weight heterogeneity of various biological materials.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1994

Effects of photoperiod and temperature on gonadal activity and plasma steroid levels in an autumn-spawning bitterling, Acheilognathus rhombea, during different phases of its annual reproductive cycle.

The kanehira bitterling, Acheilognathus rhombea, which breeds during autumn in the underyearlings and during summer and autumn in the yearlings, was exposed to various photoperiodic and temperature regimes during different phases of its annual reproductive cycle. In early autumn, gonadal development and increase in plasma levels of female estradiol-17 beta (E2) and male testosterone (T) of underyearling fish occurred under the short day length condition (12L12D). In early winter, gonadal regression (GSI reduction in both sexes, termination of vitellogenesis in females, and termination of spermatogonia proliferation in males) and decrease in plasma levels of E2 in females and T in males were induced by the low-temperature treatment (13 degrees), while gonadal maturity was maintained under the moderate temperature (20 degrees). The low temperature did not prevent oocyte maturation and ovulation in females and spermiogenesis and spermiation in males, indicating that temperature effect on gonadal activity is quite different among the maturational stages. The gonadal development of yearling fish did not progress during spring, even under the short day length condition combined with moderate temperature, which suggests that this species is in the refractory period during this season. In early summer, however, the autonomous gonadal maturation of yearling fish kept under moderate temperature progressed even under the long day length condition (15L9D). It is concluded that the causative factor in the initiation of the spawning period of the underyearling fish is the short day length in autumn, and that the causative factor in the termination of the spawning period is the low temperature in winter. An internal factor such as circannual rhythm in the yearlings is probably involved in the refractoriness to the photoperiod during spring and the subsequent earlier maturation during summer.

Animals↗
PubMed1994

Tubular dilatation in the repair process of ischaemic tubular necrosis.

To elucidate the mechanisms of renal tubular dilatation in acute tubular necrosis (ATN), morphological findings after 60 min ischaemia were studied in rats. The characteristics of the tubular basement membrane (BM) were also examined. A morphometric analysis of cell proliferation, epithelial cellularity and the circumference of damaged tubules was performed. The ischaemic injury resulted in widespread necrosis of renal tubules at day 1, and the BM of damaged tubules appeared thin. The intensity of the immunohistochemical staining for BM components decreased. The epithelial cell proliferation was particularly active in the early phase. Dilatation of the damaged tubules began at day 2, and the degree of dilatation increased up to day 6. Regenerative epithelial hyperplasia occurred and abnormalities of tubular BM were seen. Epithelial hyperplasia and dilatation of damaged tubules was most prominent at day 6 and the tubular BM was thickened by newly produced BM components. Tubular obstruction was not seen and tubules returned to normal size by day 28. Epithelial hyperplasia and abnormalities of tubular BM disappeared progressively. Regenerative tubular epithelial hyperplasia and abnormalities of tubular BM may play an important role in pathogenesis of tubular dilatation in ATN, and tubular dilatation is not due to tubular obstruction.

Animals↗
PubMed1994

Development of an experimental model of an acute respiratory failure by intratracheal sea water infusion: a comparison with a conventional oleic acid induction.

An experimental model of acute respiratory failure (ARF) was successfully developed in dogs by endotracheal sea water infusion. Serial changes in blood gases and hemodynamics, and histological changes in the lungs after use of this method were compared with those of the conventional model induced by oleic acid, and the following results were observed. Blood gases deteriorated more rapidly after sea water than after oleic acid, while the changes caused by oleic acid progressed with time, and those caused by sea water did not. Not only systemic but also pulmonary hemodynamics were adversely influenced by oleic acid, but not by sea water. Extravascular lung water was observed to increase significantly in both groups. The increase was linear after oleic acid treatment, however, while with the sea water method it leveled off to a plateau. There was no significant difference between the histological changes in lungs of the two models. Our model will provide many advantages over the conventional one using oleic acid, and will be useful for studying the pathophysiology of ARF and its therapeutic strategies, such as extracorporeal membrane oxygenation and/or carbon dioxide removal.

Acute Disease↗
PubMed1994

Supernormal atrial conduction and its relation to atrial vulnerability and atrial fibrillation in patients with sick sinus syndrome and paroxysmal atrial fibrillation.

The purpose of this study was to evaluate prospectively the relationship between supernormal atrial conduction (SNC) and the atrial vulnerability to fibrillation in patients with sick sinus syndrome (SSS) and paroxysmal atrial fibrillation (PAF). Programmed atrial stimulation was performed in 32 age-matched control patients (group I), 26 with SSS but without tachyarrhythmias (group II), and 24 with both SSS and PAF (group III) to assess some determinants of atrial vulnerability, SNC, and atrial fibrillation inducibility. Supernormal atrial conduction was observed in 20 (63%) patients of group I, 12 (46%) patients of group II, and 5 (21%) patients of group III (group I vs group III; p < 0.002). The SNC zone was 46 +/- 44 msec in group I, 36 +/- 42 msec in group II, and 12 +/- 24 msec in group III. (group I vs group III; p < 0.001). The absence of SNC showed a specificity of 89% and a positive predictive accuracy of 79% in predicting inducibility of atrial fibrillation. The sensitivity was 33% and the negative predictive accuracy was 52%. The SNC zone showed a significant inverse correlation with P wave duration (r = -0.32; p < 0.003), intraatrial conduction time (r = -0.28; p < 0.02), and maximum conduction delay (r = -0.23; p < 0.05). The maximum decrease in conduction time during supernormal conduction showed a significant inverse correlation with P wave duration (r = -0.27; p < 0.02), intraatrial conduction time (r = -0.26; p < 0.02), and with the maximum conduction delay (r = -0.27; p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

New modification of the Damus-Kaye-Stansel operation.

We report a successful modification of the Damus-Kaye-Stansel operation for transposition of the great arteries when the coronary arteries are unsuitable for transfer. The procedure includes creation of a neoaorta with end-to-end anastomosis of the proximal pulmonary artery to the distal ascending aorta and creation of an aortopulmonary window between the proximal great arteries. A valved conduit is interposed between the right ventricle and the distal pulmonary artery.

Aorta↗
PubMed1994

Transforming growth factor-beta induced class switch recombination may be modified during the cell proliferation restored by IL-2 stimulation.

Mouse spleen cells were stimulated, first by transforming growth factor beta (TGF-beta) and then by interleukin-2 (IL-2) in the presence of bacterial lipopolysaccharide (LPS). LPS plus IL-2 stimulation restored the cell proliferation suppressed by TGF-beta and increased the number of B cells. Both TGF-beta alone or TGF-beta plus IL-2 enhanced production of surface IgA-positive (sIgA+) cells in LPS-stimulated B-cell cultures. We characterized extrachromosomal circular DNAs generated in TGF-beta-primed and IL-2-stimulated B cells and identified the breakpoints of S mu/S gamma 3 recombinants which were the major intermediates of S mu and S alpha switch recombination. All switch recombination sites were dispersed evenly within both S mu and S gamma 3 regions. This even distribution of S mu/S gamma 3 breakpoints is in contrast to the site preference of class switch breakpoints induced by TGF-beta alone. These results suggest that IL-2-stimulated cell proliferation may modify class switch recombination primed by TGF-beta.

Amino Acid Sequence↗
PubMed1994

Mechanism of the suppression of repetitive atrial firing by isoproterenol--comparison with disopyramide.

To investigate whether isoproterenol (Iso) could suppress the initiation of repetitive atrial firing (RAF), we investigated its effect on RAF in comparison with that of disopyramide (Diso). Extrastimuli at a basic cycle length of 500 ms were delivered from the high right atrium in 49 patients who received an intravenous infusion of Iso (0.01 microgram/kg per min) and in 39 patients given intravenous Diso (2 mg/kg per 10 min). Induction of RAF, the atrial effective refractory period (A-ERP), and the maximum conduction delay (MCD) were measured. Iso abolished the induction of RAF in 13/19 (68%) patients, while Diso did so in 13/22 (59%) patients. Thirty-four of the 41 patients with RAF in the baseline study had an A-ERP < 250 ms and an MCD > 40 ms. Iso significantly decreased the A-ERP from 205 +/- 26 to 194 +/- 23 ms (P < 0.01) and significantly decreased the MCD from 67 +/- 24 to 39 +/- 16 ms (P < 0.0001) in 19 patients with RAF. On the other hand, Diso significantly increased the A-ERP from 203 +/- 31 to 235 +/- 36 ms (P < 0.0001), and significantly diminished the MCD from 68 +/- 31 to 55 +/- 30 ms (P < 0.01) in 22 patients with RAF. In patients with new RAF (n = 7) or re-induced RAF (n = 14) during Iso or after Diso, the MCD was more than 40 ms. Our results suggest that there are two different modes of RAF suppression, i.e. shortening or lengthening of the A-ERP.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Electrophysiologic demonstration of anterograde fast and slow pathways within the His bundle in patients with normal intraventricular conduction.

Electrophysiological evidence of functional longitudinal dissociation has been shown in different structures of the normal conduction system of the heart and in anomalous atrioventricular (AV) pathways. The typical sudden fast-to-slow jump phenomenon, which is commonly observed in patients with dual AV nodal pathways, has not been demonstrated so far within the normal His bundle. Herein we report unusual electrophysiological properties of the His bundle in two patients with normal intraventricular conduction. Of 86 patients with discontinuous anterograde AV function curves, programmed atrial stimulation revealed dual anterograde His bundle pathways in only 2 (2.3%) patients. Extrastimuli introduced at critically timed coupling intervals produced a sudden marked increase in H2-V2 interval suggesting failure of fast pathway with conduction proceeding through a slower pathway with shorter refractory period. With further decreasing coupling intervals, the second H2-V2 curve showed decremental conduction which allowed a type II gap phenomenon in the right bundle branch to occur in one of the patients. No echo beats were observed. These results provide the first electrophysiological demonstration, in patients with normal intraventricular conduction, of anterograde failure of a fast His bundle pathway with subsequent conduction through a slow His bundle pathway. His bundle duality was manifested by dual conduction times and refractory periods. These observations further expand our knowledge on the electrophysiologic properties of the His bundle.

Atrial Fibrillation↗