Biomedical subjects

K Komatsu

Publications and source records attributed to K Komatsu.

At least 325 records · Page 18Linked to original sources

PubMed1990

The reaction product of peptidylglycine alpha-amidating enzyme is a hydroxyl derivative at alpha-carbon of the carboxyl-terminal glycine.

The peptidylglycine alpha-amidating enzyme catalyzes a reaction that transforms a carboxyl-terminal glycine-extended precursor into a carboxyl-terminal alpha-amidated peptide. We purified an alpha-amidating enzyme from equine serum by simplified steps including substrate affinity chromatography. With the purified enzyme, we detected an intermediate of the alpha-amidating reaction by high performance liquid chromatography analysis. The production of the intermediate required copper, oxygen, and ascorbate and increased linearly with incubation time. The structure of the intermediate was determined to be a hydroxyl derivative at the carboxyl-terminal glycine by fast atom bombardment mass spectrometry and by proton NMR. The intermediate was readily converted into an alpha-amidated product in alkaline conditions in a nonenzymic fashion. The nonenzymic conversion required no cofactor but was extremely accelerated by the addition of copper ion or at higher temperature. Our data suggest that the direct product of the alpha-amidating reaction is not an alpha-amidated peptide but a hydroxyl derivative at the alpha-carbon of the carboxyl-terminal glycine.

Amino Acid Sequence↗

PubMed1990

A cDNA clone closely associated with non-A, non-B hepatitis.

A lambda gt11 cDNA library was constructed from RNA purified from hepatitis B viral surface antigen-negative human plasma with high alanine aminotransferase activity. A cDNA clone, designated as C8-2, was isolated by immunoscreening with mixed sera from non-A, non-B hepatitis (NANBH) carrier and convalescent chimpanzees. The recombinant protein produced by C8-2 reacted specifically with sera of patients in the chronic phase of NANBH. The sequence of C8-2, 269 bp, did not hybridized with any human or chimpanzee genomic DNA, and had no homology with those of primates and viruses. The existence of this sequence in RNA of possibly infectious plasma was shown by RNA blot hybridization and by Southern blot analysis of products amplified by the polymerase chain reaction. These results strongly suggest that C8-2 is derived from the agent of this viral hepatitis.

Amino Acid Sequence↗

PubMed1990

Enhancement of mucus accumulation in a human gastric scirrhous carcinoma cell line (KATO-III) by fibroblast-tumor cell interaction.

Human fibroblasts (WI-38 cells) were found to enhance mucus accumulation by human scirrhous carcinoma cells (KATO-III cells). Coculture of KATO-III with WI-38 cells resulted in enlargement of the KATO-III cells and increases in the proportions of PAS- and colloidal iron-positive KATO-III cells. These morphological alterations were reversed when the KATO-III cells were again cultured without WI-38 cells. Conditioned media from cultures of WI-38 cells or cocultures of KATO-III and WI-38 cells induced the same morphological alterations in KATO-III cells, suggesting that WI-38 cells produce a factor or factors that enhance mucus accumulation in KATO-III cells. This factor seemed to be a protein with a molecular weight of more than 10,000 daltons.

Adenocarcinoma, Scirrhous↗

PubMed1990

In vitro measurement of regional differences in the mechanical properties of the periodontal ligament in the rat mandibular incisor.

Mechanical testing was performed in various regions of the ligament at a velocity of intrusive loading of 5 mm/min. The perimeters of the lingual cementum and socket wall and the sectional area of the ligament were measured radiographically. Load-deformation curves were transformed into stress-strain curves using the area and width of the lingual part of the ligament. The mechanical properties of the ligament differed markedly along the long axis of the incisor; mechanical measures from the load-deformation and stress-strain curves decreased gradually from the incisal towards the basal regions. It is suggested that these regional differences in mechanical properties were much more marked than those in teeth of limited growth or in other connective tissues, and that the nature of the collagen fibres, together with surrounding cells, ground substance and blood vessels, may be important in determining such differences.

Animals↗

PubMed1990

Cavernous angioma with encapsulated intracerebral hematoma: report of two cases.

Two cases of a cavernous angioma with an encapsulated intracerebral hematoma are presented. In both instances, computed tomography scan showed a ringlike appearance with a nodular lesion. Cerebral angiograms of the two cases, however, were normal. The preoperative diagnosis for both cases was a brain neoplasm. The diagnostic problems that this type of vascular malformation presents and its role in the development of the encapsulated hematoma are discussed.

Adult↗

PubMed1990

Restoration of radiation resistance in ataxia telangiectasia cells by the introduction of normal human chromosome 11.

In order to identify the human chromosome which carries a mutated gene in cells from a patient with the hereditary disorder ataxia telangiectasia belonging to complementation group D (AT-D), we performed chromosome transfer experiments via microcell fusion. A single, pSV2neo-tagged chromosome, either 11 or 12, derived from normal human fibroblasts was introduced into AT-D cells by microcell fusion, and clones which were resistant to the antibiotic G418 were isolated. All 3 hybrid clones containing an additional copy number of chromosome 11 showed a restoration of the resistance of wild-type cells to killing by X-irradiation, whereas all 3 hybrid clones containing an additional copy number of chromosome 12 remained hyper-radiosensitive, like the parental AT cells. The results indicate that a defective gene of AT-D cells is also located on chromosome 11, since a genetic linkage analysis has previously suggested that a defective gene of its complementation group A is located on this chromosome.

Ataxia Telangiectasia↗

PubMed1990

Contribution of prostacyclin to D-tubocurarine-induced hypotension in humans.

In order to evaluate the role of prostacyclin in d-tubocurarine-induced hypotension in human, the authors examined the relationship of changes of arterial blood pressure and plasma 6-keto-PGF1 alpha level following iv administration of d-tubocurarine (dTc), with or without prior administration of aspirin and H1 antagonist. The bolus injection of dTc 0.6 mg/kg caused a significant decrease in mean arterial pressure (MAP) that was associated with a significant increase in plasma 6-keto-PGF1 alpha (P less than 0.05 in both). The maximum MAP decrease and plasma 6-keto-PGF1 alpha increase were noted at 2 min after dTc administration. Pretreatment with aspirin DL-lysine (25 mg/kg) or diphenhydramine (1 mg/kg) significantly attenuated the responses of MAP (P less than 0.05 in both) and plasma 6-keto-PGF1 alpha level (P less than 0.01 for aspirin group, P less than 0.05 for diphenhydramine group). There was a significant correlation between the changes in plasma 6-keto-PGF1 alpha and those in MAP (Kendall tau (tau) = -0.504, P less than 0.01). These findings suggest that a bolus injection of dTc induces a release of prostacyclin through H1 receptor, which is responsible for the dTc-induced transient decrease of blood pressure in humans.

6-Ketoprostaglandin F1 alpha↗

PubMed1990

Radiation dose to mouse liver cells from ingestion of tritiated food or water.

Tritium incorporated into tissues and DNA of mice was studied after daily ingestion of tritiated food or tritiated water. The tritiated food used was a commercial preparation mixed with brine shrimp that had been reared in tritiated sea water. After ingestion of tritiated food or water for up to 22 d, the specific activity of 3H in tissues was measured as tissue-free-water 3H, tissue-bound 3H, and DNA-bound 3H. Carbon-14 glucose was added to food and drinking water to compare the 3H intake from food with that from water. The specific activity of 3H in tissues was then corrected by the specific activity of 14C in tissues to determine the 3H incorporation from the same amount of ingested food and water. DNA-bound 3H after the ingestion of tritiated food was 4.6 times higher than that of tritiated water, while tissue-bound 3H was 2.2 times higher. The radiation dose to liver from 3H incorporated through food was twofold higher than from tritiated water, which was mainly from the high incorporation of 3H into DNA. Our results demonstrated that the dose calculation based on tissue-free-water 3H alone would under-estimate the radiation exposure of the human population exposed to tritiated food.

Animals↗

PubMed1990

Measurement of the force required to extract the mandibular first molar from its socket in the dissected jaw of growing young rats.

Age-related changes in the mechanical strength of the periodontal ligament have been examined by measuring the force required to extract the mandibular first molar from its socket at an extension rate of 5 mm/min in the dissected jaws of growing young rats from 3 to 32 weeks of age. Almost linear increase in the ultimate loads was found from 3 to 8 weeks of age. However the values from 8 to 32 weeks of age did not show any significant differences. Close correlations were found between the ultimate loads and the weights of animals, mandibles and extracted teeth and between the load and length of the tooth from 3 to 8 weeks of age. It is supposed that a mechanical equilibrium has been established within the periodontal ligament in association with various external and internal factors such as root elongation, alveolar bone growth, turnover and maturation of periodontal ligament and occlusal activity, at about 8 weeks of age in the rat mandibular first molar.

Aging↗

PubMed1990

Mechanical properties of the periodontal ligament in the incisor teeth of rats from 6 to 24 months of age.

Mechanical properties of the periodontal ligament of the incisor have been examined in sections of the mandibles of rats from 6 to 24 months of age. Mechanical measures estimated from the load-deformation and stress-strain curves did not show age-related changes, although the body and mandible weights increased gradually during the experimental period. It is suggested that qualitative and quantitative changes in the supporting tissues/unit area of the ligament are minor at a restricted region examined.

Aging↗

PubMed1990

[Survey on clinical isolates from 13 hospitals in Akita Prefecture--changes in frequency and susceptibility of isolates by scale of hospital. Survey Group for Clinical Isolates, Chemotherapy Research Committee of Akita Prefecture].

Isolates from various clinical materials in 13 hospitals in Akita prefecture and their drug susceptibility were investigated by the Chemotherapy Research Committee of Akita Prefecture during the period from Dec., 1987 to Feb., 1988. The results were as follows: 1. The total number of isolates was 8,387, including Staphylococcus aureus (18.9%), Pseudomonas aeruginosa (10.9%), Staphylococcus epidermidis (7.3%) and Enterococcus faecalis (6.6%). S, aureus and P. aeruginosa were detected more frequently in the larger hospitals. 2. The detection frequency of S. aureus from the sputum, throat swab and pus exudate was also very high. There was a diversity in isolates from the urine and the frequency of Escherichia coli was low. More than half of the isolates from the blood were S. epidermidis and S. aureus. Many kinds of bacteria were detected from pleural fluid and ascites, but the isolate showed no particular tendency. 3. The susceptibility of S. aureus to oxacillin were variable in hospitals, and the susceptibility to cefazolin were even lower. Low susceptibility were also seen with norfloxacin. S. aureus showed the highest susceptibility to minocycline. The susceptibility was lower for inpatients than for outpatients. P. aeruginosa showed low susceptibility to cefsulodin. The number of ampicillin-resistant Haemophilus influenzae isolates tended to decrease. Enterobacter cloacae showed a low susceptibility for cephems. Serratia marcescens showed low susceptibility to many drugs. Based on the above results, we concluded that attention should be paid to S. aureus, P. aeruginosa and Enterobacter in clinical practice.

Anti-Bacterial Agents↗

PubMed1990

Production of S-(+)-ibuprofen from a nitrile compound by Acinetobacter sp. strain AK226.

S-(+)-2-(4'-Isobutylphenyl)propionic acid [S-(+)-ibuprofen] was produced from racemic 2-(4'-isobutylphenyl)propionitrile (Ibu-CN) by an isolated bacterial strain, Acinetobacter sp. strain AK226. Ammonium acetate, acetonitrile, or n-butyronitrile as a carbon source in the culture medium was effective for bacterial growth and induction of this activity. The optimum pH of the reaction was around 8.0. S-(+)-Ibuprofen formed from Ibu-CN by resting cells was present in a 95% enantiomeric excess. Acinetobacter sp. strain AK226 appeared to possess a nitrilase for Ibu-CN because 2-(4'-isobutylphenyl)propionamide was not detected in the reaction mixture and 2-(4'-isobutylphenyl)propionamide was not hydrolyzed to S-(+)-ibuprofen. Since S-(+)-ibuprofen was preferentially produced while the R enantiomer of Ibu-CN was left almost intact over the time course of the reaction, the putative nitrilase appeared to be highly specific for the S enantiomer of Ibu-CN.

Acinetobacter↗

PubMed1990

Metabolism of a new orally active dopamine prodrug, N-(N-acetyl-L-methionyl)-O,O-bis(ethoxycarbonyl)dopamine (TA-870) and dopamine after oral administration to rats and dogs.

The metabolism of an orally active dopamine prodrug, N-(N-acetyl-L-methionyl)-O,O-bis(ethoxycarbonyl)dopamine (TA-870) and of dopamine (DA), were studied by use of thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) for identification and analysis of urinary and biliary metabolites after p.o. and/or i.v. administration to rats and dogs. The conjugated/free ratios of the metabolites were also determined. The urinary metabolites and order of the excretion in rats after p.o. dosing of TA-870 (30 mg/kg) were DA greater than homovanillic acid (HVA) greater than 3,4-dihydroxyphenylacetic acid (DOPAC) greater than 3-hydroxyphenylacetic acid (3-HPAC). Those in dogs (33.5 mg/kg p.o.) were DA greater than HVA greater than de-ethoxycarbonylated TA-870 (DEC-TA-870) not equal to DOPAC. The urinary metabolites and order of the excretion in rats after p.o. dosing of DA (12 mg/kg, equimolar dose to TA-870) were DA greater than DOPAC greater than HVA greater than 3-HPAC, while those in dogs (13.5 mg/kg) were DOPAC greater than DA greater than HVA. The composition of the main urinary metabolites of TA-870 are similar in rats and dogs but after p.o. dosing of DA, excretion of DOPAC in dogs is much (ca. 3 times) higher than that in rats. After administration of DA and TA-870, 3-HPAC was found as a novel metabolite of DA, which was thought to be formed by dehydroxylation of DOPAC or DA with intestinal flora.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗

PubMed1990

[Pharmacognostical studies on the folk medicine in Sichuan Prov. in China. II. On tu-er-feng derived from Gerbera plants].

Tu-er-feng is one of famous Chinese folk medicines in Sichuan prov. for common cold with cough, rheumatism, etc. Its sources are said to be either whole plants of some Gerbera or Ainsliaea species of family Compositae. In the recent markets, two types of Tu-er-feng are surely available. In this paper, Tu-er-feng derived from Gerbera species are studied to clarify the botanical origin; comparing mainly with the internal morphologies of the leaves and roots of G. piloselloides, G. delavayi, G. nivea, G. anandria (= Leibnitzia anandria) and G. jamesonii. As the result, G. piloselloides is determined as the botanical origin of Tu-er-feng obtained from the recent 16 markets.

Drugs, Chinese Herbal↗

PubMed1990

[Pharmacognostical studies on the folk medicine in Sichuan Prov. in China. III. On tu-er-feng derived from Ainsliaea plants].

In the previous paper, Tu-er-feng, one of Chinese folk medicines used locally in Sichuan prov., derived from the whole plants of Gerbera piloselloides of family Compositae, was pharmacognostically reported. In the recent markets, besides this known material, Tu-er-feng made of different components are found. In this paper, the Ainsliaea derivatives are studied to clarify the botanical origins; comparing anatomically with leaves and petioles of thirteen Ainsliaea species growing wildly in Sichuan prov. The result shows that A. glabra and A. rubrinervis are the ingredients.

Drugs, Chinese Herbal↗

PubMed1990

[A 17-year experience with ileal conduit urinary diversion--early and late complications].

A series of 185 patients, 133 males and 52 females, were treated by ileal conduit urinary diversion in the past 17 years. The patients ranged in age from 7 months to 81 years with an average of 59 years. Diversions were performed for malignant diseases in 174 patients, 85% of whom underwent a simultaneous radical surgery. The follow-up covered the postoperative period from 4 months to 16 years 8 months with an average of 4 years 8 months. Six patients (3%) died within 1 month of operation, and 43 of a total of 58 mortal cases died of cancer thereafter. The survival rates of 143 patients with bladder cancer were 84% for 1 year, 72% for 3 years, 67% for 5 years, 62% for 10 years and 54% for 15 years. Early complications were noticed in 38% of the patients. Delayed wound healing due to local infection (20%) and intestinal obstruction (10%) were the two major complications in this period. Late complications were encountered in 51% of the patients. Mild peristomal dermatitis (22%) and gradually developing renal complications (22%) are two major problems in the standard ileal conduit urinary diversion. The latter was significantly more frequent in patients who underwent the operation between 1973 and 1981 than in those who had the surgery between 1982 and 1989. Postoperative hydronephrosis was observed in 15 (13%) of 117 patients who showed normal urograms preoperatively. Ileoureteral reflux was observed in 50% of the cases with nonobstructing conduits, while it increased up to 70% along with obstruction of the conduit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

[Diffusion of ofloxacin (OFLX) into prostatic tissue in patients with benign prostatic hypertrophy].

Diffusion of ofloxacin (OFLX) into prostatic tissue was studied in 31 patients with benign prostatic hypertrophy. Concentrations of OFLX in the serum and prostatic tissue were measured at scheduled intervals after 200 mg OFLX oral administration. The mean OFLX level in prostatic tissue and tissue/serum ratio at 2 hours, 4 hours and 6 hours was 3.33 +/- 0.96 micrograms/g (1.25 +/- 0.28) in 10 patients, 2.21 +/- 0.55 micrograms/g (0.92 +/- 0.32) in 9 patients and 2.10 +/- 0.99 micrograms/g (1.01 +/- 0.23) in 12 patients, respectively. OFLX levels in prostatic tissue covered the minimum inhibitory concentration for several pathogenic bacteria detected from the infected prostatic fluid. Therefore, OFLX was thought to be a very useful drug for the treatment of bacterial prostatitis and postoperative infection of prostatic surgery.

Administration, Oral↗

PubMed1990

[The diameter of main pancreatic duct on endoscopic retrograde pancreatography and the appearance of main pancreatic duct on computed tomography: a comparative study].

We have carried out a comparative study of the diameter of main pancreatic duct (MPD) on endoscopic retrograde pancreatography (ERP) with the frequency of detection of MPD by computed tomography (CT) in order to clarify the importance of MPD appearance on CT in the pancreatic and biliary diseases. The normal MPD on ERP was demonstrated by CT in a low frequency. MPD was most frequently observed in the pancreatic body on CT. The dilatation of MPD on ERP was found in both moderate and advanced pancreatitis group. However, the significant demonstration of MPD by CT was found in advanced group alone. We observed that CT finding of dilated duct correlated with that on ERP in advanced group alone.

Cholangiopancreatography, Endoscopic Retrograde↗