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Biomedical subjects

K Komatsu

Publications and source records attributed to K Komatsu.

At least 343 records · Page 19Linked to original sources
PubMed1990

Serial transmission of a putative causative virus of enterically transmitted non-A, non-B hepatitis to Macaca fascicularis and Macaca mulatta.

In order to establish an animal model and to identify a causative virus of enterically transmitted non-A, non-B hepatitis, Macaca fascicularis was inoculated with a fecal extract obtained from Myanmar patients with acute sporadic non-A, non-B hepatitis. The primates developed acute hepatitis exhibited by a transient elevation of aminotransferases in the sera and occurrence of hepatic necroinflammation between 2 and 4 weeks postinoculation. Subsequent second passage of the fecal extract made from first-passage primates into another Macaca fascicularis and Macaca mulatta induced acute hepatitis. Likewise, third passage was also successfully performed. Immune electron microscopy of the stool extract incubated with the primate serum at the acute phase of hepatitis showed an aggregation of virus-like particles. These particles consisted of full and empty round particles without an envelope, measuring approximately 27 nm in diameter. A dispersion of similar particles was found ultrastructurally in the hyaloplasm of hepatocytes surrounding the focal necrosis. This putative causative virus appears to be a new hepatitis virus.

Animals↗
PubMed1990

Occurrence and character of a putative causative virus of enterically-transmitted non-A, non-B hepatitis in bile.

The present investigation confirms the possibility that the etiological agent of enterically-transmitted non-A, non-B (ET-NANB) hepatitis (type E hepatitis), multiplied in hepatocytes, is excreted into the feces via bile. The fecal extract was inoculated into 7 cynomolgus monkeys. Bile juice was collected directly from the gallbladder by needle puncture after abdominal operation 3 to 6 times during the experimental course. All 7 monkeys developed elevated serum aminotransferases, which began gradually approximately 2 weeks postinoculation and reached a peak at 3 to 5 weeks. In parallel with this elevation, both in time and magnitude, necroinflammation was observed in the livers. The virus-like particles (VLPs) were found in the bile juice of all 7 monkeys and the serial occurrence of VLPs was typified as follows: the VLPs were negative on day 7, appeared on day 10 after inoculation, and were present until the 3rd week when the subjects were sacrificed. While the particles were individually dispersed on day 10, they started to exhibit spontaneous aggregation on and after week 2. Also, empty particles were very rare at first, but increased in ratio compared to full ones over time. Thus, the putative causative virus of ET-NANB hepatitis was demonstrated to be excreted through bile. The spontaneous aggregation of VLPs might be due to the specific antibody secreted into the bile juice and was closely correlated with hepatitis activity. The increase in empty particles might indicate an increase in disorganized assembly of the nucleic acid and protein during virus proliferation.

Animals↗
PubMed1990

[Transmittance of light-cured composite resins. 1. Measurement of transmittance with time].

The factors that influence the change of the transmittance of light-cured composite resins during polymerization were examined. Six experimental composite resins such as used organic composite filler and fourteen commercial composite resins were investigated using the experimental device for measurement of the transmittance. The transmittance of the experimental composite resins were from 25 to 73%. The transmittance of the experimental composite resins changed with time; a group with increasing transmittance (G1), a group giving a maximum transmittance (G2), and a group with decreasing transmittance (G3). These changes of transmittance were influenced by the difference in the refractive indices between matrix resin and filler, but the refractive index that indicated a maximum transmittance of matrix resin during polymerization could not be observed when the refractive index of the matrix resin and filler was same. The light transmitted through the commercial composite resins was less than half of the irradiation light. This change of transmittance could also be classified into the three groups mentioned above. The commercial composite resins belonged to the group with increasing transmittance (G1).

Composite Resins↗
PubMed1990

[Shrinkage stress developed by polymerization of composite resin].

The effects of the shrinkage stress on the various cavity forms, were examined. The shrinkage stress was obtained from the displacement of the brass mold developed by polymerization of the composite resin. The shrinkage stress developed in the cavity wall, was analyzed by the finite element method, and the crack of the cylindrical silica tube filled with composite resin, was observed. The shrinkage stress 30 minutes after mixing the composite resin was reduced with the increase in the marginal angle as well as the diameter or the depth of cavity. Preparation of the bevel at the cavity margin reduced the shrinkage stress. In the case of reverse bevel, reduction of the stress was not observed within 24 hours, but in the other cases, the stress immediately decreased after hardening. The analysis by the finite element method reveoled the maximum stress at the margin, with less stress for the round, flat and reverse bevel in this order. For the observation of the cylindrical silica tube filled with composite resin, the crack was observed in the cylindrical silica tubes prepared round, flat or without bevel, it was not observed in the tube prepared reverse bevel that the crack was developed in this tube and composite resin was detached from this tube within 24 hours.

Composite Resins↗
PubMed1990

Medication-induced esophagitis in children.

Clinical and endoscopic features of two pediatric cases of esophageal ulcers caused by capsules of oxytetracycline and doxycycline are described. Several cases of medication-induced esophageal injury in children have been reported until now, all of which were in association with tablets or capsules. Antibiotics are known to be responsible for medication-induced esophagitis in adults. In this study, 4 cases were caused by emepronium bromide and 3 cases, including the present patients, by antibiotics. All cases but one complained of chest pain and/or dysphagia. Although the interval between the onset of the symptoms and the diagnosis varied among cases, the clinical courses were relatively uneventful, without any long-term sequelae. This clinical entity seems to be unfamiliar to pediatricians and is omitted from the differential diagnosis.

Child↗
PubMed1990

[Effect of high-dose methotrexate on cerebral metabolic rate of glucose in rats and children with acute lymphoblastic leukemia].

For assessment of high-dose methotrexate (HD-MTX) neurotoxicity, regional cerebral metabolic rates of glucose (rCMRGlu) in rats and children with acute lymphoblastic leukemia were measured. rCMRGlu in rats receiving HD-MTX (300 or 600 mg/kg) was measured using 14C-deoxyglucose and autoradiographic technique. CMRGlu of the whole brain after HD-MTX was reduced by 31% on the average (p less than 0.01). CMRGlu of cerebral cortex was reduced more than that of white matter. Eight children with ALL (mean age 9.6 years) were studied using 18F-fluorodeoxyglucose and positron emission tomography before and after HD-MTX (200 mg/kg or 2,000 mg/M2) therapy. Although no patients clinically showed any neurological abnormalities during HD-MTX therapy, CMRGlu of the whole brain after HD-MTX was reduced by 21% on the average (p less than 0.05). Reduction rates of rCMRGlu after HD-MTX therapy were correlated with both total doses of intrathecal MTX (r = 0.717, p less than 0.05) and total doses of systemic HD-MTX (r = 0.784, p less than 0.05). The reduction rate of CMRGlu of cerebral cortex, particularly frontal and occipital cortex, was greater than either that of basal ganglia or white matter. It is suggested that measurement of rCMRGlu after HD-MTX is useful for detecting accumulated neurotoxicity of MTX.

Adolescent↗
PubMed1990

[Report of a case successfully weaned from long left ventricular assist with complete recovery after coronary artery bypass grafting].

A 45-year-old female underwent coronary artery bypass grafting (CABG) due to medically uncontrollable unstable angina. After completion of CABG, left ventricular contraction was remarkably diminished to maintain systemic circulation. Because intraaortic balloon pumping and veno-arterial bypass with large amount of catecholamines could not improve left ventricular wall function, we decided to use left ventricular assist device (LVAD). After application of LVAD, the patient could easily be weaned from cardio-pulmonary bypass. LVAD was used for 25 days and the patient was successfully weaned from LVAD too, and are now living 6 months postoperatively. As far as we know, this case is the first survival patient after the longest cardiac assist in our country.

Acute Disease↗
PubMed1990

[The measurement of extra vascular lung water using a thermal-sodium double indicator dilution technique in patients undergoing surgery for esophageal cancer].

The Extra Vascular Lung Water (EVLW) was measured using the thermal sodium double indicator dilution technique in 21 patients undergoing surgery for esophageal cancer. This measurement is an important parameter in the control of the respiratory function. In the 16 cases without pulmonary complications, the preoperative EVLW was 5.3 +/- 0.2 (mean +/- SEM) ml/kg and the immediate postoperative EVLW was 4.8 +/- 0.4 ml/kg. This change was significant (p less than 0.05), but within 24 hours the EVLW returned to almost the same levels as those recorded before surgery. In only 3 cases, the EVLW were elevated beyond 7.5 ml/kg, but these high EVLW levels did not continue for more than 12 hours. Of the 5 patients with pulmonary complications, only two experienced pulmonary edema. Their preoperative EVLW levels were normal, but the immediate postoperative EVLW levels were significantly elevated beyond 10 ml/kg. These elevated levels were observed before the PaO2, the portable chest roentgenograms and the other test results changed following surgery. The high EVLW levels beyond 7.5 ml/kg continued for 72 hours after surgery. We found no correlation between the EVLW and measureable hemodynamic parameters (Cardiac Index, Pulmonary Wedge Pressure, Colloid Osmotic Pressure-Pulmonary Wedge Pressure gradient) during the observation period. In the other cases with pulmonary complications (2 cases were pneumonia, one was atelectasis with pneumonia), the changes in the EVLW levels were the same as for the cases without pulmonary complications. These results indicate that the EVLW is the optimum parameter for the control of the respiratory function and early diagnosis of pulmonary edema after surgery for esophageal cancer.

Esophageal Neoplasms↗
PubMed1989

[Combined effect of cis-DDP (II), OK-432 and systemic hyperthermia in ascites tumor in mice].

Combined effect of cis-DDP (II) (CDDP), a streptococcal preparation (OK-432) and systemic hyperthermia on ascites tumor in mice was studied. Tumor cells were of a syngeneic cloned cell line FMA3 which was derived from Furth's mastocytoma. When number of cells transplanted into the abdominal cavity was at 10(5), a single i.p. injection of CDDP at a dose of 4 mg/kg was effective to increase the mean survival time by a factor of 1.6. OK-432 given i.p. at a dose of 5 KE/kg on every two days between day 2 and day 10 after transplantation decreased the mean survival times. Even when it was used in combination with CDDP, enhancement of the effect of CDDP was not statistically significant. However, by the factorial analysis of the all data obtained in the experiments carried out with tumor cells of the number of 10(2), 10(3), 10(4) and 10(5), enhancement of the effect of CDDP by OK-432 was significant. Systemic hyperthermia of the core-body temperature of 40 degrees C was not effective when used alone, and did not enhance the effect of CDDP. However, combined use of it and OK-432 significantly enhanced the effect of CDDP.

Animals↗
PubMed1989

Anorectal motility after rectal myectomy in patients with Hirschsprung's disease.

Anorectal manometric studies were performed 42 times in 13 patients with rectal myectomy and 137 times in 49 cases treated by the PTCF method. The resting pressure of the anal canal was found to be lowered just after the operation and remained at levels lower than those in normal controls and in patients with rectal myectomy. This fact was attributed to the resection of the muscle layer in the anal canal. On the other hand, the resting pressure of the anal canal in patients undergoing the PTCF method decreased after the operation and recovered to normal levels within 3 years after the operation. This finding correlates with the clinical condition of bowel habits. The resting pressure of the rectum elevated and remained high for more than 3 years in patients with rectal myectomy. This finding can be explained by the high tonus of the rectum oral to the aganglionic bowel which was left after rectal myectomy. The resting pressure of the rectum in patients treated by the PTCF method elevated just after the operation. It was lowered, however, to the normal level within about 3 years after the operation. Regarding the data of basal rhythmic waves, no significant change was observed Regarding the data of basal rhythmic waves, no significant change was observed in comparison with normal controls. The rectoanal reflex was observed only twice out of the 42 studies in patients with rectal myectomy and in nine of 137 studies in patients treated by the PTCF method. There was no relationship between the presence of reflex and clinical bowel habits.

Adolescent↗
PubMed1989

Gastric acid secretion in a child with postbulbar duodenal ulcer.

A 14-year-old case was reported with a primary postbulbar duodenal ulcer, which was confirmed by barium meal study and duodenoscopy. In the preoperative study, the patient showed marked gastric hyperacidity: maximal and peak acid output were 0.980 and 1.434 mEq/kg/hr, respectively. As previously described, hyperacidity appears to be a main factor in the pathogenesis of postbulbar duodenal ulcer. Fasting and postprandial serum gastrin secretion was not thought to be responsible for gastric hyperacidity in the present case. Upon histological investigation, the operatively resected stomach did not suggest a possible relationship between hyperacidity and an enlarged parietal cell mass.

Adolescent↗
PubMed1989

Loss of virulence in Shigella strains preserved in culture collections due to molecular alteration of the invasion plasmid.

Fifty-two Shigella strains long preserved by three Japanese culture collections were examined for virulence. All of them were avirulent when judged by the focus-plaque assay and the ability to bind Congo red. Fifteen strains had a plasmid comparable in size to that responsible for epithelial invasiveness and were positive in hybridization tests with a probe derived from a plasmid cistron, virG. Twenty-four strains had a similar plasmid but were negative in hybridization tests. The remaining 13 strains were negative in all the five criteria for virulence. Similar studies made on one hundred Shigella strains isolated from 1967 to 1985 clearly demonstrated loss of virulence with prolonged time of storage.

DNA, Bacterial↗
PubMed1989

Secretion of transforming growth factor-beta by human myelogenous leukemic cells and its possible role in proliferation of the leukemic cells.

Transforming growth factor (TGF)-beta activity was found in the neutral extracts of human myelogenous leukemic cells or K562 cells and the conditioned medium from K562 cell culture. BALB/c 3T3 cells grown in soft agar in the presence of TGF-beta 1 produced an activity that stimulated the growth of K562 cells. This activity was non-dialyzable, acid-stable, heat-sensitive and partially inactivated by pronase treatment. These results suggest a mutual growth reliance between the leukemic cells and fibroblasts mediated by paracrine growth factors produced by these cells.

Animals↗
PubMed1989

Potentiation of invasive capacity of rat ascites hepatoma cells by transforming growth factor-beta.

The in vitro invasive capacity of poorly invasive cells (W1), which were cloned from rat ascites hepatoma cells (AH 130), was potentiated dose- and time-dependently by pretreating the cells with transforming growth factor-beta (TGF-beta). This potentiation of invasive capacity was completely abolished by anti-TGF-beta antibody. When the treated cells were ip inoculated into rats, the cells extensively invaded the peritoneum, and formed penetrating tumor nodules. The effect of TGF-beta was reversed by subculturing the treated cells without TGF-beta. The potentiation of invasive capacity by TGF-beta might participate in platelet-associated enhancement of tumor cell metastasis.

Animals↗
PubMed1989

A dual transcriptional activation system for the 230 kb plasmid genes coding for virulence-associated antigens of Shigella flexneri.

The expression of plasmid-encoded, invasion-related antigens lpa b, c and d of Shigella flexneri was found to be positively regulated at transcriptional level by a 33kD protein produced by the previously defined, virulence-associated Region 1 on the SalI fragment B of the 230 kb invasion plasmid. The gene (designated virB) was identified and its nucleotide sequence determined. No Ipa b or c was produced in the absence of an intact virB gene although lower levels of d were produced. The previously reported regulatory activity of the virF gene some 30 kb distance away was shown to act exclusively through virB. In contrast, the activation of the virG gene necessary for intercellular spread occurred directly by virF without the requirement for virB. This study thus ascribes a critical function to a previously recognized, but functionally undefined, virulence locus on the large invasion plasmid of S. flexneri. The virF gene appears to have a central role in activation of the 230 kb plasmid-encoded virulence genes.

Amino Acid Sequence↗
PubMed1989

Functional organization and nucleotide sequence of virulence Region-2 on the large virulence plasmid in Shigella flexneri 2a.

The 7 kb virulence Region-2 of the large (virulence) plasmid in Shigella flexneri 2a encodes several proteins required for invasion of intestinal epithelial cells. Insertion and deletion mutagenesis, DNA subcloning and SDS-polyacrylamide gel electrophoresis of proteins synthesized in minicells demonstrated five genes in this region. They encode 24, 18, 62 (IpaB), 41 (IpaC) and 37 (IpaD)-kiloDalton (kD) proteins. Complementation of Tn5-induced mutations in Region-2 with the above plasmid constructs indicated that Region-2 consists of two operons and that the three Ipa proteins are essential for the virulence phenotype. The transcriptional organization determined by Northern blotting, S1 nuclease protection and the effect of Tn5 insertions on expression of the Ipa proteins revealed that Region-2 has three promoters that transcribe RNAs of 4.0, 4.5 and 7.5 kb. The 4.0 kb RNA was the transcript for the operon encoding the 24, 18 kD, IpaB and C proteins and the 4.5 kb RNA for the ipaD gene. In addition, the full-length RNA of 7.5 kb which covers Region-2 supplemented full expression of the Ipa proteins. The 7663 nucleotides of Region-2 were determined to confirm the five open reading frames encoding 23,655, 17,755, 62,168, 41,077 and 36,660 Dalton proteins, respectively, and their regulatory sequences.

Amino Acid Sequence↗
PubMed1989

Intravenous administration of isosorbide dinitrate attenuates the pressor response to laryngoscopy and tracheal intubation.

In order to evaluate the effect of isosorbide dinitrate (ISDN), administered as a bolus intravenous injection, on the circulatory response to tracheal intubation, mean arterial pressure (MAP), and heart rate (HR) in response to laryngoscopy for 30 s followed by tracheal intubation were compared in patients not receiving ISDN (control) and receiving 40 micrograms/kg or 80 micrograms/kg of ISDN 45 s before starting laryngoscopy. Each group consisted of 10 patients undergoing elective surgery. Forty-five seconds after starting laryngoscopy, MAP was significantly (P less than 0.01) lower in patients receiving 80 micrograms/kg ISDN than in those receiving no or 40 micrograms/kg ISDN. HR increased to a similar extent in the three groups. These results indicate that a bolus injection of ISDN (80 micrograms/kg) is a simple, practical and highly effective means of attenuating the hypertensive response to direct laryngoscopy and tracheal intubation.

Adult↗