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Biomedical subjects

M Katayama

Publications and source records attributed to M Katayama.

At least 199 records · Page 11Linked to original sources
PubMed1991

A geranylgeranyltransferase for rhoA p21 distinct from the farnesyltransferase for ras p21S.

We have clarified that rhoA p21 purified from bovine aortic smooth muscle is geranylgeranylated at the cysteine residue in the C-terminal CAAX motif (A is an aliphatic amino acid and X is any amino acid). In this paper, a geranylgeranyltransferase for rhoA p21 (rhoA p21 GGT) was partially purified from bovine brain cytosol. This enzyme transferred a geranylgeranyl moiety from geranylgeranyl pyrophosphate to rhoA p21 having the CAAX motif (rhoA p21-CAAX) but not to rhoA p21 lacking the AAX portion. rhoA p21 GGT was separated from the previously reported farnesyltransferase for ras p21s (ras p21 FT) by column chromatographies and did not geranylgeranylate or farnesylate c-Ha-ras p21-CAAX. ras p21 FT did not geranylgeranylate or farnesylate rhoA p21-CAAX. These results indicate that rhoA p21 GGT distinct from ras p21 FT is present in bovine brain cytosol.

Alkyl and Aryl Transferases↗
PubMed1991

Heparin-binding (fibroblast) growth factors are potential autocrine regulators of esophageal epithelial cell proliferation.

A serum-free culture system supplemented with neural tissue extract for normal and tumor human esophagi was applied to the culture of mouse esophageal epithelium. Similar to mouse mesenchyme and skin epithelium, esophageal epithelial lines (MEE) emerged after serial culture. The cells had an apparent unlimited life span but retained morphology and other characteristics of normal epithelial cells. The cells formed a small cyst consisting of keratinized squamous epithelium in syngenic hosts. A screen for growth factors that stimulated growth of the nonmalignant MEE cells in the absence of neural extract revealed that epidermal growth factor (EGF) and heparin-binding (fibroblast) growth factors (HBGF) were most effective. An HBGF-like activity was apparent in extracts of rapidly proliferating but not quiescent MEE cells at low or confluent densities. A cloned cell line (MEE/C8) was selected from MEE cell cultures in the absence of neural extract. MEE/C8 cells proliferated independent of either EGF or HBGF at rates equal to MEE cells, cell extracts exhibited HBGF-like activity at all stages of proliferation, and the cells formed large invasive tumors in syngenic hosts. The HBGF-like activity present in extracts of tumorigenic MEE/C8 and proliferating nonmalignant MEE cells had properties similar to HBGF-1 (acidic fibroblast growth factor). These results constitute a cultured mouse esophageal epithelial cell model for study of conversion of immortalized premalignant cells to malignant cells, and suggest that conversion from a state of cell cycle-dependent autocrine expression of one or more members of the HBGF family to a state of constitutive expression correlates with and may contribute to malignancy.

Animals↗
PubMed1991

Continuous cardiac output determination by thermodeprivation.

A modified thermodilution catheter (KATS catheter) capable of monitoring continuous cardiac output by thermodeprivation and preserving its conventional function was devised. The KATS catheter has a thermistor incorporated closer to the tip of the catheter in addition to the usual thermistor used for conventional thermodilution. This additional thermistor is heated by a constant electric current but is capable of measuring its own temperature. The degree of heat deprivation is detected as the cooling of the thermistor, which is proportionally larger with larger blood velocity. Since blood flow is not the only source of heat deprivation, the actual formula was empirically derived by performing in vitro studies. Cardiac output can be determined by assuming the cross sectional area of the pulmonary artery is stationary. Calibration can be derived from a cardiac output measurement by the usual thermodilution method with the same catheter. The KATS catheter readings correlated significantly with conventional thermodilution values and electromagnetic flowmeter readings in anesthetized dogs. Continuous cardiac output measurement by the KATS catheter appears to be a promising technique.

Journal Article↗
PubMed1991

Direct measurement of calpastatin subtypes by sandwich enzyme immunoassay using monoclonal antibodies.

Six stable hybridoma cell lines secreting monoclonal antibodies to human calpastatin were established. All monoclonal antibodies belong to the IgG1 subclass and recognized different epitopes on calpastatin. At least two groups were distinguished; the first group was specific for muscle-type (M-) calpastatin and the second group recognized not only M-calpastatin but also erythrocyte-type (E-) calpastatin. The inhibitory effect of all monoclonal antibodies on calpastatin activity was relatively low even at high concentrations of antibodies. Enzyme immunoassay systems were developed for direct determination of calpastatin subtypes in human cells requiring no other sample treatment than the disruption of the cells. The assay methods were, in principle, based on the sandwich enzyme immunoassay using epitope-specific monoclonal antibodies. The enzyme immunoassay system for M-calpastatin was specific for M-calpastatin and could not detect E-calpastatin. The enzyme immunoassay system for total calpastatin detected not only M-calpastatin but also E-calpastatin. The sensitivity of these assay systems was 10 pmol l-1 of calpastatins. Antigenicity of calpastatins was found to be unchanged in the presence of EDTA and haemoglobin. Good reproducibilities of within-and between-assay series and excellent recovery of exogenous calpastatins from cell lysates were observed. From these results, it seems that our newly developed subtype-specific enzyme immunoassay systems for calpastatins are useful in biochemical studies and clinical testing for determination of calpastatin subtypes.

Antibodies, Monoclonal↗
PubMed1991

Lymphocytic hypophysitis and pulmonary sarcoidosis. Report of a case.

Lymphocytic hypophysitis is one of the causes of hypopituitarism in the postpartum period. Some of these patients have been reported to have other organ-specific autoimmune diseases, and the disease is considered to be autoimmune in nature. The authors describe a unique case of lymphocytic hypophysitis in a young woman. She had hemianopia that developed three days after delivery. Computed tomography scans revealed an intrasellar mass lesion. Secretions of adrenocorticotropic hormone and growth hormone were decreased. Although no organ-specific autoantibodies were detected in her serum, OKT4-positive helper T lymphocytes were increased in peripheral blood. Pituitary biopsy at craniotomy showed typical features of lymphocytic hypophysitis. Pulmonary and eye sarcoidosis developed 11 months after the delivery. This is, to the authors' knowledge, the first case of lymphocytic hypophysitis associated with sarcoidosis in other organs.

Adult↗
PubMed1991

Metabolic changes in patients severely affected by tetanus.

Metabolic changes in six severely affected tetanus patients suffering from characteristic labile hypertension (maximum systolic blood pressure greater than 200 mmHG, maximum diurnal change in systolic pressure greater than 100 mmHg) were investigated. Daily urinary excretion of urea nitrogen increased gradually from the onset of opisthotonus, reached a peak value (10.4 to 15.4 g/m2) in 8 to 20 days, and decreased subsequently. Average cumulative excretion in 30 days reached 239.6 +/- 32.7 g/m2. Urine catecholamine excretion was elevated in each patient and remained elevated during this period. Plasma cortisol and glucagon concentrations were not increased markedly except in a case complicated other systemic bacterial infection. Increased protein catabolism in these patients could not be explained by the metabolic effects of 'stressed hormones' alone, and neurologic factors must be considered.

Adult↗
PubMed1991

Decrease of gastrointestinal mucosal damage by salicyluric acid compared with salicylic acid in rabbits.

The gastrointestinal mucosal damage following the oral administration of salicylic acid or salicyluric acid was examined in rabbits using a scanning electron microscope. Six and 24 h after treatment with salicylic acid, morphological changes of gastric mucosa were recognized. In rabbits treated with salicyluric acid, however, severe damage in the gastric mucosa was not found after 24 h compared with the treatment with salicylic acid. Following the treatment with salicylic acid, some mucosal damage in the duodenum, jejunum and ileum was observed after 24 h. The surface character of the duodenal, jejunal, ileal, caecal and colonic mucosa were almost identical compared with the control following the treatment with salicyluric acid. It was reported that salicyluric acid is metabolized to salicylic acid by the intestinal microorganisms. From these results, it was suggested that prodrugs utilizing the metabolism of salicyluric acid to salicylic acid by intestinal microorganisms may be useful in reducing gastrointestinal mucosal damage.

Administration, Oral↗
PubMed1991

Effect of sodium D-3-hydroxybutyrate on amino acidemia in hemorrhagic hypotension.

The effect of sodium D-3-hydroxybutyrate (3-OHB) on the amino acidemia caused by hemorrhagic stress was studied. Rats were infused 3-OHB (3-OHB group, n = 11) at a rate of 30 mumol/min.kg or the same volume of saline (control group, n = 11) for 1 h prior to hemorrhage. Mean arterial pressure was maintained at 40 mm Hg using reserved bottle for 30 min. While ketosis was suppressed in control group, plasma ketone body concentration increased from 2,062.9 +/- 223.7 to 3,151.4 +/- 794.8 mumol/l in the 3-OHB group during hemorrhage. Although significant difference in plasma concentrations of amino acids were not shown between two groups at the onset of shock, it was shown after 30 min of shock in alanine, proline, and threonine. Particularly severity of hyperalaninemia was clear. In the control group plasma alanine concentration increased as shock proceeded (p less than 0.01), and no significant change was shown in the 3-OHB group. These results indicate that pretreatment with 3-OHB suppress the hyperalaninemia seen in hemorrhagic hypotension. Ketone body administration may inhibit the protein catabolism in stressed states, such as hemorrhagic hypotension.

3-Hydroxybutyric Acid↗
PubMed1991

Urinary fibronectin fragments (a potential tumor marker) measured by immunoenzymometric assay with domain-specific monoclonal antibodies.

We found that urinary fibronectin (UFN) in cancer patients was almost all fragmented and consisted mainly of the cell-binding domain. We developed a two-site immunoenzymometric assay for UFN, using two monoclonal antibodies that both recognize this domain of fibronectin. The amount of UFN was expressed as arbitrary units per milligram of creatinine. Some 2% of the 623 healthy subjects had UFN above the clinical cutoff point (200 arb. units/mg creatinine), as did 14% of the 271 patients with nonmalignant diseases. In contrast, concentrations of UFN exceeded the cutoff point in 59% of the 589 patients with cancer. In 37 patients with gastrointestinal cancer tested for UFN and for one or more of three established serum tumor markers, UFN was found in 25, significantly more often than the other markers. These results indicated that UFN is a marker that may be helpful in evaluating many kinds of cancer.

Adult↗
PubMed1991

[Immunoscintigraphy of colorectal cancer with 111In labeled anti-CEA monoclonal antibody (ZCE-025)].

Clinical trials with 111In labeled anti-CEA monoclonal antibody (ZCE-025) was initiated. Five patients with colorectal cancer suspected were given an intravenous injection of 1 mg of 111In labeled ZCE-025. Planar and SPECT images were obtained 24 and 72 hours after injection. Surgical operation was performed on all patients between 7 and 10 days post injection. Of 4 primary sites, all were clearly visualized. Intrahepatic metastasis was visualized as higher activity than normal liver in one of two patients. In one patient whose imaging was negative, no residual cancer was found at surgery. Persistent accumulation of 111In in the lymph nodes was also observed in one patient. Surgical exploration of these lymph nodes showed no gross or microscopic evidence of metastases of colon cancer. No side effects were encountered, although HAMA were detected in all 5 patients by 4 weeks after the administration of ZCE-025. Immunoscintigraphy appears useful in distinguishing recurrent tumor from postoperative granuloma. Further investigation directed to the causes of 111In accumulation in tumor-free lymph nodes is required.

Aged↗
PubMed1991

Deleted mitochondrial DNA in the skeletal muscle of aged individuals.

Human mitochondrial DNA deletions occur mainly in the major region between the origins of replication of the heavy and light strands both in mitochondrial myopathy and in the ageing process. To determine whether deletions in the minor region also contribute to the ageing process, we analyzed a 3,610-basepair deletion (nucleotide position 1,837-5,447, from the 16S rRNA gene to the ND2 gene) in the skeletal muscle from individuals of various ages. The direct repeated sequence at each boundary of the deletion was identified as 5'-CCCC-3'. This minor-region deletion was detected in one of five individuals of the sixth decade, two of five in the seventh decade, and all of five in the eighth decade, but not in individuals below age 60. These results indicate that age-related accumulation of mtDNA deletions occurs not only in the major region but also in the minor region.

Adolescent↗
PubMed1991

Post-translational modifications of the C-terminal region of the rho protein are important for its interaction with membranes and the stimulatory and inhibitory GDP/GTP exchange proteins.

We have recently found, by use of the rhoA p21 purified from bovine aortic smooth muscle, that it is similarly post-translationally processed as described for ras p21s: it is first geranylgeranylated at the cysteine residue in the C-terminal region followed by removal of the three C-terminal amino acids and the subsequent carboxyl methylation of the revealed C-terminal cysteine residue. In the present study, we investigated the function(s) of these post-translational modifications of the C-terminal region of rhoA p21 by use of the rhoA p21s purified from bovine aortic smooth muscle and rhoA p21-overexpressing Escherichia coli since the bacterial protein was not modified with a geranylgeranyl moiety. Bovine rhoA p21 bound to plasma membranes and phosphatidylserine-linked Affigel, but bacterial rhoA p21 did not bind to them. The inhibitory GDP/GTP exchange protein for rhoA p21, named GDP dissociation inhibitor (GDI), made a complex with the GDP-bound form of bovine rhoA p21 and thereby inhibited the dissociation of GDP from and the subsequent binding of GTP to it. However, rho GDI neither made a complex with the GDP-bound form of bacterial rhoA p21 nor affected these reactions of the bacterial protein. The stimulatory GDP/GTP exchange protein for rhoA p21, named GDP dissociation stimulator (GDS), stimulated the dissociation of GDP from bovine rhoA p21, but was inactive for the bacterial protein. In contrast, the GTPase activating protein for rhoA p21 is active not only for bovine rhoA p21 but also for the bacterial protein. These results suggest that the post-translational modifications of the C-terminal region of bovine rhoA p21, most presumably the geranylgeranylation, which are absent in bacterial rhoA p21, play important roles in its interaction with membranes and the stimulatory and inhibitory GDP/GTP exchange proteins but not with the GAP.

Animals↗
PubMed1991

Effect of 3-hydroxybutyrate on posttraumatic metabolism in man.

Of 20 patients suffering trauma, with Injury Severity Scores greater than 20, 11 patients received DL-3-hydroxybutyrate (3-OHB) at a rate of 25 mumol/kg/min for 3 hours. The remaining nine patients received sodium DL-lactate at the same rate as the control subjects. With increased arterial concentrations of ketone bodies, the femoral arteriovenous difference (arterial concentration minus venous concentration) of ketone bodies increased proportionally in the 3-OHB group (R = 0.853, p less than 0.001). Venous concentrations of nonesterified free fatty acids, alanine, glycine, and valine were decreased significantly in the 3-OHB group as compared to the control group. The concentration difference between femoral vein and artery (venous concentration minus arterial concentration) for these substrates also decreased, indicating decreased release from the extremity. A decrease in venous concentration of alanine and difference between femoral vein and artery reached 102.3 +/- 69.3 mumol/L and 32.6 +/- 22.8 mumol/L (mean +/- SD), respectively, after 3-OHB infusion. Decreased alanine release from muscle during 3-OHB infusion in traumatized patients suggests a suppressive effect of ketone body on posttraumatic protein catabolism.

3-Hydroxybutyric Acid↗