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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 757 records · Page 42Linked to original sources
PubMedDate not supplied

Antiretroviral activities of anthraquinones and their inhibitory effects on reverse transcriptase.

Alizarin complexone (AC), alizarin Red S (ARS) and various other anthraquinones were evaluated for their inhibitory effects on Rous-associated virus 2 reverse transcriptase (RAV-2 RT). Some 1,2-dihydroxyanthraquinones were active against this enzyme and AC was the most potent inhibitor among these compounds [50% inhibitory concentration (IC50): 3.8 micrograms/ml]. AC slightly inhibited Rous sarcoma virus RT (RSV RT) and human immunodeficiency virus type 1 RT (HIV-1 RT) (IC50: 100 micrograms/ml and 45 micrograms/ml, respectively). However, AC efficiently inhibited focus formation by Rous sarcoma virus (RSV) and cytopathogenicity of human immunodeficiency virus type 1 (HIV-1). Simultaneous administration of AC with RSV to newborn chickens also delayed tumor induction by RSV.

Animals↗
PubMedDate not supplied

Mechanism of influenza virus transcription inhibition by matrix (M1) protein.

The mechanism by which influenza virus matrix (M1) protein inhibits viral RNA (vRNA) transcription was investigated. Evidence has been generated that M1 protein inhibits the steps of vRNA transcription initiation and reinitiation more effectively than that of RNA chain elongation. The vRNA-associated nucleocapsid protein (NP) appears to be critical for this inhibition, implying that M1 protein binds to the ribonucleoprotein complex (RNP) through NP.

Capsid↗
PubMedDate not supplied

Peroxidase-linked anti-basic fibroblast growth factor monoclonal antibody Fab' conjugates: application for two-site enzyme immunoassay and immunohistochemical detection.

After conjugating thiol groups in the hinge region of monoclonal antibody (mAb) Fab' fragments specific for basic fibroblast growth factor (bFGF) with maleimido-horseradish peroxidase HRP) complexes synthesized by incubation of HRP with the heterobifunctional reagent N-succinimidyl-4-(maleimidomethyl)cyclohexane-1-carboxylate, we developed a fluorometric enzyme immunoassay method based on the sandwiching of the factor between anti-bFGF IgG-coated polystyrene beads and the conjugates, and also an immunohistochemical method for detection of the location of the factor. The discriminatory detection limit by the developed enzyme immunoassay (EIA) was as low as 30 pg/mL. The reproducibility of within- and between-assay series was 6.07-9.18% and 6.28-6.82%, respectively, and the recovery of exogenous bFGF from serum was approximately 98%. The curves generated by the concentrated fraction that eluted at the same position as standard bFGF by size-exclusion chromatography on a TSK 2000SW column were parallel to the curve for standard bFGF. From these results, we consider the developed EIA method to be acceptable in regard to sensitivity, precision, and specificity. Also, without the introduction of any additional signal amplification system, positive immunohistochemical reactions were successfully detected by the HRP-linked anti-bFGF mAb Fab' in fibroblastic and endothelial cells, which have already been shown to synthesize and secrete bFGF, indicating that these conjugates provide a useful means for direct immunohistochemical detection of the factor.

Antibodies, Monoclonal↗
PubMedDate not supplied

Sensitive fluorescence in situ hybridization signal detection in maize using directly labeled probes produced by high concentration DNA polymerase nick translation.

The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30 kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected.

Chromosomes, Plant↗
PubMedDate not supplied

Dysembryoplastic neuroepithelial tumors: MR findings.

OBJECTIVE: We report MR findings in three patients with dysembryoplastic neuroepithelial tumor (DNT), which is a recently described benign tumor in childhood or young adolescents. MATERIALS AND METHODS: The MR studies of three patients with surgically proven DNT were reviewed. All cases presented with partial complex seizures. Axial and coronal T1- and T2-weighted MR imaging of the head was performed using a 1.5 T MR unit. T1-weighted imaging after Gd-DTPA was also performed. RESULTS: The tumors were located mainly in the cortical to subcortical area with very little perifocal mass effects on MR imaging. They were essentially hypointense on T1-weighted imaging and hyperintense well-demarcated mass on T2-weighted imaging and retained a thick gyrus-like configuration within the lesions. None of them exhibited contrast enhancement after administration of Gd-DTPA. CONCLUSION: Differentiation of DNT from gangliogliomas or other low grade gliomas is possible using these MR features and is important because DNT does not recur after epilepsy surgery, therefore postoperative radiation and chemotherapy are not needed.

Adult↗
PubMedDate not supplied

Pruritus and hydration state of stratum corneum in hemodialysis patients.

BACKGROUND: Xerosis is the most frequent cutaneous manifestation in hemodialysis (HD) patients, but the association between dry skin and pruritus remains to be clarified. Since the skin surface hygrometer can detect the changes of water content in the stratum corneum more sensitively, we re-examined the relationship between the severity of pruritus and water content in dialysis patients. METHODS: Fifty patients who had been undergoing regular HD were examined for the degree of pruritus by clinical grading. Water contents in the stratum corneum at volar forearm and lower leg were assessed by measurement of high-frequency conductance using a skin surface hygrometer both at pre- and postdialysis. RESULTS: Thirty-seven (74%) of dialysis patients complained of pruritus. High-frequency conductance values were significantly lower in HD patients compared to those of age-matched control subjects (n = 13) both at forearm (35.1+/-3.0 vs. 73.3+/-10.4 microS, p<0.01) and lower leg (14.2+/-1.1 vs. 52.4+/-7.5 microS, p<0.01). There was no relationship between the severity of pruritus and age, gender, HD duration, underlying renal disease, or removing fluid volume. A significant reduction of itching score was found in patients using polysulfone membrane. A single HD session using cellulose triacetate or polysulfone membrane significantly increased water content both at forearm and lower leg (p<0.05). However, the degree of pruritus did not correlate with the skin water content both at the beginning and the end of HD session, respectively. CONCLUSION: It follows from these findings that water content in the stratum corneum was reduced in HD patients, but did not correlate with the severity of pruritus.

Adult↗
PubMedDate not supplied

Psoas abscess with osteomyelitis in a patient undergoing long-term hemodialysis.

We describe a 69-year-old male patient on maintenance hemodialysis for 24 years who developed a fatal left psoas abscess with osteomyelitis at the hip joint following acute enterocolitis. He had systemic beta(2)-microglobulin amyloid deposition in colon epithelium and psoas muscle. Cultures from abscess fluid and femoral bone marrow yielded Bacteroides fragilis. To our knowledge, this is the first case on hemodialysis having a psoas abscess following acute gastrointestinal infection. This rare case suggested that a secondary psoas abscess could be one of the occult infections in patients undergoing long-term maintenance hemodialysis.

Aged↗
PubMedDate not supplied

Effects of cycloheximide on chromatin-bound and -unbound PCNA in HeLa cells.

We examined the effects of cycloheximide on the amount of chromatin-bound and -unbound PCNA subpopulations in HeLa cells. The chromatin-bound PCNA content decreased rapidly in the presence of cycloheximide, whereas the reduction of the total amount of PCNA was minimal even 24 h after the treatment with cycloheximide. From these data, the half-life of PCNA was estimated to be 31.0 h for chromatin-bound PCNA and 276.8 h for the total.

Chromatin↗
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Observation of the otolithic membrane by low-vacuum scanning electron microscopy.

Untreated specimens (i.e. not fixed, dehydrated or embedded) of the otolithic membrane from the sacculus of guinea pigs were observed at the ultrastructural level by low-vacuum scanning electron microscopy (LVSEM). This technique revealed the presence of a 15- to 20-mu m-thick layer of an amorphous substance (the supraotolithic cupula zone) on the surface of the otoliths, which was not detectable by conventional methods. Elemental analysis of this substance revealed relatively high concentrations of oxygen, sodium, phosphorus, chlorine, potassium and calcium. This amorphous substance was thought to have a role in fixing the otoliths onto the sensory epithelium. In addition, the tips of the triangular portions of the otoliths were not sharp as shown by conventional SEM and were seen to be more rounded by LVSEM.

Animals↗
PubMedDate not supplied

Temporal bone pathology of a patient with cochlear implant.

A 66-year-old man with profound total deafness received a 22-channel cochlear implant. After surgery, his hearing improved and the postoperative course was uneventful except transient vertigo. The patient died of lung cancer after 2.5 years. Twelve hours after death, the temporal bone was harvested for histological and electron microscopic examination. The mastoid air cells were preserved, although a few mucosal folds were present. The Dacron mesh tie had largely been absorbed, but part remained embedded in fibrous tissue. No inflammation was noted in the tympanic cavity or the round window through which the electrodes were inserted. In the cochlea, the scala tympani was filled with fibrous tissue at the site of electrode insertion. The scala media had collapsed, while the organ of Corti and stria vascularis showed degeneration. Osseous spiral bundles and spiral ganglion cells were noted, though reduced in number.

Aged↗
PubMedDate not supplied

Use of short-lived 18F and long-lived 14C in double tracer autoradiography for simultaneous measurement of LCBF and LCGU.

We have developed a quantitative autoradiographic technique for the simultaneous measurement of local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) using a combination of 14C-long-lived and 18F-short-lived radionuclides as labels. To obtain the LCGU image, a 50-fold greater radioactivity of 18F than of 14C was administered and the first exposure was done for 2 hours. Three days later, when most of the 18F had decayed, a second exposure was done for 5 to 6 days to obtain the LCBF image. 18F standards were prepared in each experiment. The technique provides, for the first time, the local glucose flow ratio (LGFR). LGFR, obtained by dividing the LCGU by the LCBF image, was expressed as percent mumol/ml (multiplied by 100). Measurement of these three values in the same animal is expected to prove useful in the investigation of the pathophysiology of the brain. The advantages of this method are that cross contamination is less than 4%, chemical or physical manipulation of the slices is unnecessary, and final results can be obtained within a week.

Animals↗
PubMedDate not supplied

Recurrence of anti-glomerular basement membrane antibody glomerulonephritis.

Recurrence of anti-glomerular membrane antibody glomerulonephritis seems to be an unusual clinical phenomenon. We report a 57-year-old man with recurrence of anti-glomerular basement membrane antibody glomerulonephritis. He developed a rapidly progressive glomerulonephritis with anti-glomerular basement membrane antibody (anti-GBM Ab), and recovered with a combined treatment of prednisolone, anticoagulant and antiplatelet agents. After a 2-year remission, hematuria and proteinuria followed by renal functional deterioration occurred without any obvious cause. The second renal biopsy revealed cellular crescents with linear IgG deposition along GBM, a finding similar to the first one. The aforementioned combined treatment resulted in a gradual recovery from proteinuria and renal functional derangement.

Antibodies↗
PubMedDate not supplied

Electron microscopical study of the structure of liposome-type artificial red blood cells stabilized with carboxymethylchitin.

Stable liposome-type artificial red blood cells containing either an aqueous bromothymol solution or erythrocyte haemolysate were produced using carboxymethylchitin as a stabilizer. The structure of the resulting vesicles was investigated by electron microscopy after freeze-fracturing, freeze-substitution and negative staining. The vesicles were not homogeneous but contained unilamellar and multilamellar structures. The maximum size was about 2 microns; most vesicles were about 200-500 nm in size. The carboxymethylchitin did not yield a continuous layer but rather occurred in patches on the membrane surface probably forming a mesh-like layer over the entire liposome surface.

Chitin↗
PubMedDate not supplied

Preparation and stability of liposome-type artificial red blood cells stabilized with carboxymethylchitin.

Liposome-type artificial red blood cells stabilized with carboxymethylchitin (mean diameter 310 nm) were prepared by a two-step emulsification technique. Sheep haemolysate was dispersed as fine droplets in a lecithin solution in dichloromethane to yield a W/O-type emulsion. The W/O emulsion thus obtained was then dispersed in an aqueous carboxymethylchitin solution to give a W/O/W-type complex emulsion. Removal of the organic solvent by evaporation from the complex emulsion left an aqueous suspension of the artificial red blood cells. The haemoglobin-trapping efficiency of the cells was found strongly dependent on the pH of the carboxymethylchitin solution used. The artificial red blood cells underwent disintegration by the action of surfactants. When a comparison was made among those surfactants which have the same alkyl chain length, the degree of cell disintegration was in the increasing order, anionic greater than cationic greater than nonionic. Globulin and fibrinogen produced no disintegration of the cells while albumin disrupted the cells to a slight extent.

Animals↗
PubMedDate not supplied

Mechanism of cold ischemia-reperfusion-induced graft injury after orthotopic liver transplantation in rats.

BACKGROUND/AIMS: The purpose of this study was to clarify the mechanism of cold ischemia-reperfusion-induced graft injury after liver transplantation, especially with regard to the relationship between hepatocyte, sinusoidal endothelial cell injury, and hepatic hemodynamic alteration. METHODOLOGY: We evaluated changes in hepatocyte and sinusoidal endothelial cell function, and hepatic hemodynamics after reperfusion in an isogeneic rat liver-transplantation model. The livers of male LEW rats were stored in 4 degrees C lactated Ringer's solution for 1 hr, 3 hr (viable graft), and 6 hr (nonviable graft) before implantation. After reperfusion, hepatocyte function was assessed by serum alanine aminotransferase level and bile output; sinusoidal endothelial cell function was evaluated by serum hyaluronic acid level. Furthermore, we measured hepatic venous oxygen saturation, and portal venous blood flow using a transit time blood flow meter. RESULTS: At 2 hr after reperfusion, the hepatocyte function was similar in all groups. However, the sinusoidal endothelial cell function deteriorated severely in the nonviable graft group, and significantly decreased hepatic venous oxygen saturation levels were observed, suggesting poor hepatic circulation. At 4 hr after reperfusion, the hepatocyte injury was markedly increased in the nonviable graft group. Although systemic blood pressure remained stable, significantly decreased portal venous blood flow in the nonviable graft group was found compared with the viable graft groups. Histopathological studies showed that massive ischemic necrosis was seen in zone III (central) of hepatic lobule 8 hr after reperfusion in the nonviable graft group. CONCLUSIONS: These data suggest that the sinusoidal endothelial cell injury was predominant in the early phase of reperfusion, and might cause microcirculatory disturbances, resulting in decreased portal venous blood flow. This phenomenon may subsequently cause ischemic damage to the hepatocyte, with eventual graft failure.

Animals↗