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Biomedical subjects

M Katoh

Publications and source records attributed to M Katoh.

At least 307 records · Page 17Linked to original sources
PubMed1990

Sialates and negative charge on the surface of syncytiotrophoblastic cells of full-term placentae in toxemic patients.

In the syncytiotrophoblastic surface of the toxemic full-term placentae, the sialates and their consequent negative charging were studied by both electron microscopic histochemistry (Ferritin method) and Western blot analysis. Evidence is presented showing (1) that the reactions with both the ferritin labelled Limulus Polyphemus Agglutinin (LPA-ferritin), specific to sialates, and the cationized ferritin, specific to a negative charge, decrease in the specimens of toxemic placentae, (2) that the density of sialates in placentae of severe gestational proteinuria or/and hypertension is statistically lower than that of severe gestational edema, and (3) that there is no difference between the blotted bands in normal placentae and toxemic ones regardless of the severity of the toxemia. These results indicate that the reduction of the surface negative charging is demonstrated in toxemic syncytiotrophoblasts and appears to be secondary to the decrease in the amount of sialate.

Adult↗
PubMed1989

Effects of intravenously administered human atrial natriuretic peptide on elevated blood pressure during surgery.

The effect of human atrial natriuretic peptide (hANP) on blood pressure (Bp) was evaluated in 11 patients who had elevated systoric Bp of over 150 mmHg during surgery. A bolus injection of 50 microg or 100 microg of hANP decreased Bp with an immediate response by 27.6 +/- 3.1 mmHg (P < 0.001) or 40.7 +/- 4.2 mmHg (P < 0.001), respectively, accompanying with tremendously increased urine output. Heart rate and PaO2 were not altered. Thus, a intravenous bolus injection of hANP is an useful therapeutic tool for the treatment of acutely elevated Bp during anesthesia.

Journal Article↗
PubMed1989

Chromosome malsegregation and embryonic lethality induced by treatment of normally ovulated mouse oocytes with nocodazole.

The mouse egg is ovulated with its nucleus arrested at the metaphase-II stage of meiosis. Sperm entry triggers the completion of the second meiotic division. It has been speculated that damage to the meiotic spindle of normally ovulated eggs at around the time of sperm entry could result in chromosome malsegregation and the death of conceptuses with numerical chromosome anomalies. This hypothesis was tested using nocodazole, a microtubule inhibitor. Nocodazole was administered either to maturing preovulatory oocytes or to normally ovulated eggs at one of the following stages: (1) the time of sperm entry, (2) early pronuclear stage, (3) pronuclear DNA synthesis, (4) prior to first cleavage division, (5) early 2-cell stage, or (6) prior to the second cleavage division. Little or no effect was observed for treatment times other than the time of sperm entry, when the egg is being activated to complete the second meiotic division. Remarkably high frequencies of embryonic lethality, expressed at around the time of implantation, were induced at this stage. Cytogenetic analysis of first cleavage metaphases of zygotes treated at the time of sperm entry revealed a high incidence of varied numerical chromosome anomalies, with changes in ploidy being predominant.

Aneuploidy↗
PubMed1989

Fetal anomalies produced subsequent to treatment of zygotes with ethylene oxide or ethyl methanesulfonate are not likely due to the usual genetic causes.

Earlier studies in this laboratory revealed that ethylene oxide (EtO) or ethyl methanesulfonate (EMS) induced high frequencies of midgestation and late fetal deaths, and of malformations among some of the surviving fetuses, when female mice were exposed at the time of fertilization of their eggs or during the early pronuclear stage of the zygote. Effects of the two mutagens are virtually identical. Thus, in investigating the mechanisms responsible for the dramatic effects in the early pronuclear zygotes, the two compounds were used interchangeably in the experiments. First, a reciprocal zygote-transfer study was conducted in order to determine whether the effect is directly on the zygotes or indirectly through maternal toxicity. And second, cytogenetic analyses of pronuclear metaphases, early cleavage embryos, and midgestation fetuses were carried out. The zygote transplantation experiment rules out maternal toxicity as a factor in the fetal maldevelopment. Together with the strict stage specificity observed in the earlier studies, this result points to a genetic cause for the abnormalities. However, the cytogenetic studies failed to show structural or numerical chromosome aberrations. Since intragenic base changes and deletions may also be ruled out, it appears that the lesions in question induced in zygotes by the two mutagens are different from conventional ones and, therefore, could be a novel one in experimental mammalian mutagenesis. Alternatively, the mechanism could involve a non-mutational 'imprinting' process that caused changes in gene expression.

Abnormalities, Drug-Induced↗
PubMed1989

Human chorionic gonadotropin in colorectal cancer and its relationship to prognosis.

The presence of human chorionic gonadotropin in large bowel cancers was studied immunohistochemically using an immunoperoxidase technique. HCG-positive tumour cells were present in 42 of 194 adenocarcinomas examined (22.0% of colon cancer and 21.2% of rectal cancers). On histological grading, the hCG-positive rate tended to rise as the degree of differentiation decreased. HCG was detected more frequently in cancers invading the total bowel wall (27%) than in those invading the partial wall (17.1%). Lymph node, liver or peritoneal metastases were present more frequently in hCG-positive tumours than in hCG-negative tumours. Furthermore, there was an intimate correlation between the presence of hCG-positive tumour cells and CEA doubling times in nine cases with untreated liver metastasis. The survival rate for patients with tissue hCG-positive cells was lower than for those with hCG-negative tumours. Thus, the presence of tissue hCG in colorectal cancers may be a biological marker of prognostic significance.

Adenocarcinoma↗
PubMed1989

[Clinical significance of serum NCC-ST 439 as a tumor marker for colorectal cancer].

Clinical significance of preoperative serum NCC-ST 439 level was studied in 119 cases of colorectal cancer (90 of primary, 29 cases of recurrent). The positive rates for serum NCC-ST 439 were 28.9% in primary and 65.5% in recurrent cases. The false positive rates for benign disease were 5.6%. These rates were low when compared with those for other tumor markers. The positive rates for serum NCC-ST 439 exhibited a strong correlation with wall invasion, lymph node and liver metastases. A combination assay of NCC-ST 439, CEA and CA 19-9 produced a high positive rates as 43.3% in primary and 86.2% in recurrent cases. These results demonstrate that measurement of serum NCC-ST 439 may be useful for cancer staging and improves the diagnostic rate in combination with CEA and CA 19-9.

Adenocarcinoma↗
PubMed1989

Potential role of Kupffer cells in initiating liver injury during endotoxemia.

The potential contribution of Kupffer cells (KCs) to endotoxin-induced liver damage was evaluated by measuring the functional changes of KGs [Superoxide (O2-) generation, and chemotaxis (CTx)] isolated from such livers and comparing them with biochemical and histological changes of liver damage. Sublethal doses of endotoxin was daily administered to rats for 4 days. Liver damage was apparent in the rats treated with single administration of endotoxin and the maximal change was observed in the rats treated with endotoxin for 2 days in association with the marked enhancement of O2- release and CTx in vitro by KCs from these animals. However, liver injury decreased in the rats treated with endotoxin for 3 days and the rats treated with endotoxin for 4 days had shown almost no detectable injury. KCs' biological functions also diminished in group treated for 3 and 4 days. In particular, oxidative and chemotactic responses of KCs from rats treated for 4 days significantly decreased, compared with the cells from those treated for only two days. These results indicate that KCs are pivotal in the pathogenesis of liver injury during endotoxemia.

Animals↗
PubMed1989

[Hepatic artery and portal vein infusion of adriamycin in experimental liver metastasis].

Hepatic artery and portal vein infusion of adriamycin (ADM) to normal rabbit and the experimental liver metastasis model of VX2 tumor were discussed in this study. The concentration of ADM in the peripheral blood, liver, myocardium, lung of normal rabbit and metastatic tumor were measured in the HPLC method. There was no difference between arterial infusion and portal infusion in the normal rabbits. In the metastatic tumor, one hour after the infusion, concentration of ADM showed no difference between arterial and portal infusion, but two and three hours later, the concentration was significantly higher after portal infusion than arterial infusion. It was suspected that portal infusion would be more effective for liver metastasis. The number of tumor nodules for estimation of the anti-tumor effect on metastatic models was decreased significantly after arterial and portal infusion compared with the controls, but there was no statistical difference between arterial and portal infusion.

Animals↗
PubMed1988

Effect of pre-exercise fructose ingestion on endurance performance in fed men.

Twelve trained males, in a fed state, were studied to examine the effect of pre-exercise fructose ingestion on endurance capacity during prolonged cycling exercise. Sixty minutes prior to exercise, subjects ingested either 60 or 85 g fructose or a sweet placebo. Mean exercise intensity initially required 62% of the maximal aerobic power and thereafter increased to elicit 72 and 81% of maximal aerobic power at 90 and 120 min of exercise, respectively. Exercise time (mean +/- SE) to exhaustion was significantly increased after fructose ingestion, as compared to placebo ingestion (145 +/- 4 vs 132 +/- 3 min, P less than 0.01). During the exercise, no differences were observed between both trials for oxygen uptake, heart rate, or perceived exertion. Serum glucose and insulin levels between both trials were not significantly different throughout the experiment. There were also no significant differences in serum-free fatty acids and glycerol levels as well as respiratory exchange ratio between fructose and placebo trials during the exercise. The results suggest that fructose ingestion is of benefit before prolonged exercise, because it provides a carbohydrate source to contracting muscles without transient hypoglycemia and a depression of fat utilization, and thereby delays the fatigue.

Adolescent↗
PubMed1988

Inhibition by opioid agonists and enhancement by antagonists of the release of catecholamines from the dog adrenal gland in response to splanchnic nerve stimulation: evidence for the functional role of opioid receptors.

The aim of the present study is to examine how opioid agonists and antagonists modify the splanchnic nerve stimulation (SNS)-induced release of catecholamines from the dog adrenal gland in vivo, in an attempt to elucidate whether opioid receptors play a functional role in controlling catecholamine release. Output of epinephrine (EPI) and norepinephrine (NE) was determined from adrenal venous blood by using high-performance liquid chromatography with electrochemical detection. SNS (0.3, 1 and 3 Hz) produced increases in both EPI and NE output in a frequency-dependent manner. Leu-enkephalin (10-100 micrograms/kg i.v.) and morphine (10-100 micrograms/kg i.v.) attenuated the increase in EPI and NE output induced by 1 or 3 Hz of SNS without affecting the basal catecholamine output. A 25 to 40% reduction of the SNS-induced increase in catecholamine output was observed after the treatment with 100 micrograms/kg of leu-enkephalin or morphine. The increase in EPI and NE output induced by 1 and 3 Hz of SNS was enhanced markedly by naloxone (10-1000 micrograms/kg i.v.) and by naltrexone (10-1000 micrograms/kg i.v.). The SNS-induced increase in catecholamine output doubled after treatment with 100 and 1000 micrograms/kg of naloxone or naltrexone. Basal catecholamine output and the increase in output induced by 1 Hz of SNS were unaffected by naloxone or naltrexone. These results suggest that endogenously released opioid peptides inhibit the release of catecholamines by activating opioid receptors in the adrenal gland of the dog.

Adrenal Glands↗
PubMed1987

Antithrombin III microheterogeneity in antithrombin III deficiency and in the antithrombin III abnormality, "antithrombin III Toyama".

Antithrombin III (AT III) microheterogeneity was investigated in 12 cases of congenital AT III deficiency and 2 cases of congenital AT III abnormality by isoelectric focusing (IEF) and immunofixation. In congenital AT III deficiency, IEF and immunofixation revealed AT III as 8 bands which was indistinguishable from normal control in terms of the number of bands and the isoelectric point (pI) of each band. In the proband of the congenital AT III abnormality, however, IEF and immunofixation showed AT III as 8 bands which shifted slightly but definitely to the acidic side compared to those of normal subjects. This change in pI of the abnormal AT III was considered to reflect the amino acid replacement in the polypeptide chain of the abnormal AT III molecule.

Adult↗
PubMed1987

Purification of prolactin receptors from sow mammary gland and polyclonal antibody production.

After solubilization with Triton X-100 or 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate (CHAPS), prolactin receptors from mammary crude membranes of primiparous lactating sows (pretreated with bromocriptine) have been purified by affinity chromatography using ovine prolactin or a monoclonal antibody against rabbit prolactin receptor. Comparative analysis of these two methods of purification demonstrated that use of an immunoaffinity step allowed a great improvement of receptor yield (40%) compared to the hormone affinity method (10%). In addition, partially purified fractions obtained by immunoaffinity appeared more homogeneous and had much higher specific activity. Affinity labelling of prolactin receptors from crude membranes or solubilized extracts with iodinated ovine prolactin, followed by electrophoretic analysis (SDS-PAGE) and autoradiography, revealed one binding unit of approximately 45 kDa. When partially purified receptor preparations were labelled with 125I, submitted to an additional affinity chromatography and analyzed by SDS-PAGE, prolactin receptors appeared as a single form having a molecular weight of 42-45 kDa, which is not associated with itself or other subunits by disulfide linkages. Partially purified fractions were used to produce anti-prolactin receptor serum from goats. These polyclonal antibodies were able to completely inhibit the binding of lactogenic hormones in sow and rabbit mammary membranes. They were also able to recognize hormone-receptor complexes, but more specifically in sow mammary gland. These antisera could inhibit prolactin binding to its receptors in several organs of various species, suggesting that prolactin receptors shared numerous antigenic similarities between species and particularly between sow and rabbit. These similarities appeared to be located essentially on the part of the molecule more specifically involved in the recognition of the hormone.

Affinity Labels↗