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J Kato

Publications and source records attributed to J Kato.

At least 487 records · Page 27Linked to original sources
PubMed1988

Gene organization in the region containing a new gene involved in chromosome partition in Escherichia coli.

A new mutation, parC, causing abnormal chromosome segregation was identified in two thermosensitive mutants of Escherichia coli. The thermosensitive growth of the mutants was corrected by pLC4-14 in the Clarke-Carbon collection. This plasmid carries a putative gene which can suppress the cell division defect due to ftsI (pbpB) and has hence been termed sufI (sui). The nearness of parC to metC was confirmed, and cotransduction frequency of parC was 59% with metC and 20% with glc. The parC-sufI region was analyzed by subcloning the chromosome region of pLC4-14. The parC and the sufI gene products were electrophoretically identified as proteins of 75 and 55 kilodaltons (kDa), respectively. The allelism of parC+ on pLC4-14 to parC1215 was confirmed by cloning parC1215. The sufI gene appeared to be dispensable for cell viability, and overproduction of its product caused suppression of ftsI. An essential gene coding for a 25-kDa protein was found between the parC and the sufI gene. These three genes were transcribed in the same direction and may be organized into an operon, with parC to the proximal side and with internal promoters at least for the distal genes. The localization of the gene products was examined in maxicells. The sufI protein was synthesized as a precursor which could be chased into a mature form. The major part of the mature form was found in the soluble fraction. The 25-kDa protein was found almost exclusively in the membrane fraction. The parC protein was associated with the membrane fraction in the presence of Mg2+ but found in the soluble fraction when Mg2+ was sequestered with EDTA.

Bacterial Proteins↗
PubMed1988

Substitution of Ser-17 of pp60c-src: biological and biochemical characterization in chicken embryo fibroblasts.

pp60c-src is phosphorylated mainly on Ser-17 and Tyr-527 in vivo. In this study, we examined the effect of the phosphorylation of Ser-17 on the properties of pp60c-src by introducing Rous sarcoma virus variants carrying pp60c-src in which Ser-17 had been substituted, into chicken embryo fibroblasts. The Ala-17 substitution in wild-type pp60c-src and pp60c-src carrying Phe-527 caused a two- to threefold elevation in the kinase activity in vitro of these proteins; the former variant resulted in no morphological changes of infected cells, whereas the latter variant transformed chicken embryo fibroblasts. Since the substitution of Tyr-527 per se has been reported to activate pp60c-src, these results suggest that the abolishment of the phosphorylation of Ser-17 does not affect noticeably the properties of pp60c-src in chicken embryo fibroblasts.

Animals↗
PubMed1988

Effect of phosphatidyl inositol on progesterone receptors in rat uterine cytosol.

It was reported that unsaturated long chain fatty acids, such as arachidonic acid, oleic acid and docosahexaenoic acid inhibit the binding between progesterone and estrogen receptors and steroid hormones. Most of the long chain fatty acids are contained in phospholipids within the cells. The effect of phospholipids on the binding between R5020 and progesterone receptors was studied. Phosphatidyl ethanolamine and sphingomyelin had no effect on binding, but phosphatidyl inositol and phosphatidyl serine inhibited the binding 53% and 34% respectively. The effect of phosphatidyl inositol on the binding between R5020 and progesterone receptors was dose dependent. Scatchard analysis revealed that the addition of phospholipid markedly decreased the number of binding sites from 1398 fmol/mgp to 258 fmol/mgp, but the dissociation constant was little affected.

Animals↗
PubMed1988

Changes in uterine estrogen receptor concentrations in persistent estrous and persistent diestrous rats.

Changes in uterine weight and the estrogen receptor concentrations were examined in persistent estrous (PE) and persistent diestrous (PD) rats at 80 days of age. To prepare PE rats, 100 micrograms estradiol benzoate (EB) was injected sc into 3-day-old females. PD rats were obtained by daily injections of 10 micrograms EB into females for 10 consecutive days from the day of birth. The uterine weight in PE rats at 80 days was comparable to that in metestrous controls. The uteri of PD rats were smaller than those in PE rats. The concentrations of estrogen receptor in nuclear fractions in PE and PD rats were much lower than those in proestrous controls. Receptor concentrations in cytosol fractions were significantly lower in PE and PD rats than in control diestrous, proestrous and estrous rats. The dissociation constants and sedimentation coefficients of estrogen receptors in PE and PD rats were found to be in the same range as those in control rats. Thus, the reduction in the activity of cytosol receptors in these rats is attributable to a quantitative change in the amount of estrogen receptor protein. To study the response of the uterus to estrogen, ovariectomized rats were injected daily with 10 micrograms estradiol for 7 consecutive days. The uterine growth of PE and PD rats after administration of estradiol was less marked than in controls, indicating a reduction of estrogen sensitivity of the uterus. Seven daily administrations of estradiol continued to increase the concentration of uterine cytosol estrogen receptor in controls. In contrast, in PE and PD rats, the receptor concentrations continued to increase during the first 3 days, and then remained constant. These data suggest that EB in neonatal treatment may directly affect the mechanism of receptor synthesis in uterine tissues. This effect may contribute to the reduction of the uterine response to estrogen.

Animals↗
PubMed1988

Inhibitory effect of fatty acids on the binding of androgen receptor and R1881.

Unsaturated long chain fatty acids are known to inhibit the binding between estrogen and estrogen receptor, or progesterone and progesterone receptor in rat uterus. The effects of long chain fatty acids on the binding between androgen receptor of castrated rat prostate and 3H-R1881 were studied. The binding was not affected by saturated fatty acids such as palmitic acid (16:0) or stearic acid (18:0). But unsaturated fatty acids such as oleic acid (18:1), arachidonic acid (20:4) and docosahexaenoic acid (22:6) inhibited the binding between androgen receptor and 3H-R1881. The inhibitory effect of arachidonic acid was dose dependent. Scatchard analysis showed that the addition of arachidonic acid markedly decrease the number of binding sites of androgen receptor. But the dissociation constant was not affected. The inhibitory effect of arachidonic was not a competitive one.

Animals↗
PubMed1988

Quantitation and characterization of serum transferrin receptor in patients with anemias and polycythemias.

Serum transferrin receptor concentration in patients with anemias and polycythemias was determined. The mean normal value was 258 +/- 82 ng/ml. Comparing with normal values, the higher values were obtained in patients with iron deficiency anemia, autoimmune hemolytic anemia, and polycythemias, while the lower values were obtained in patients with aplsatic anemia. During treatments of patients with iron deficiency anemia and autoimmune hemolytic anemia, serial change of serum receptor was paralleled with that of peripheral reticulocyte counts, suggesting that the circulating receptor values may reflect the activity of bone marrow erythropoiesis. The immunoreactive receptor was migrated at the position of alpha 1-globulin by agarose gel electrophoresis and the isoelectric point(pl) was 3.57 by isoelectric focusing. SDS-polyacrylamide gel electrophorogram of various patients' sera revealed that the autoradiographed band was migrated at the molecular weight of 110,000 daltons in the non-reducing condition and 46,000 and 23,000 daltons in the reducing condition. These bands were also capable of binding to 131I-labelled diferric transferrin. The proposed model of circulating transferrin receptor may be the nicked dimers of 55,000 daltons in which inter- and intra-disulfide bridges were present.

Anemia↗
PubMed1988

[Studies involving 11 cases of early gastric cancer with a widespread lymph node metastasis].

Over the past 10 years, we have experienced 11 cases of early gastric cancer limited to the mucosa and submucosa, with a widespread lymph node metastasis over the perigastric node. These cases represented 3.8% of all the early gastric cancer cases treated at our hospital during this period. The average age of these patients was 49.1 years, and consisted of 7 males and 4 females. Of these 11 cases, 10 cases (90.9%) were, macroscopically, the depressed type. Histologically, 7 cases (63.6%) were poorly differentiated carcinoma. Curative resections were possible in 8 cases (72.7%). The cumulative 5-year survival rate was poorer than for other types of early gastric cancer, and amounted to 66.7% in cases that were curative, and 0% for non-curative cases.

Adenocarcinoma↗
PubMed1988

[Targeting chemotherapy with transferrin-neocarzinostatin conjugate].

In efforts to obtain preferential uptake of anticancer agents into tumors, we explored the possibility of delivering such agents by transferrin receptor-mediated endocytosis. Human diferric transferrin was conjugated with neocarzinostatin (NCS) using N-succinimidyl 3-(2-pyridyldithio)-propionate. This conjugate is capable of binding to the transferrin receptor and is internalized by endocytosis. The inhibitory effect of the conjugate on cell growth was remarkable when a human colorectal cancer cell line, M7609 was used as a target in vitro. In addition, in vivo efficacy of the conjugate in inhibiting the growth of M7609 cells implanted subcutaneously into nude mice was also observed when the conjugate was administered through a tail vein. The observed toxicity was a transient decrease in the red blood cell count, which returned to normal within 14 days. The half disappearance time of the conjugate was 55 min, while that of free NCS was 7 min. No serious side effects with regard to liver or kidney function were detected. This conjugate is an appropriate model for the receptor-mediated delivery of ligand-drug complex and may be useful for future clinical application.

Animals↗
PubMed1988

[Treatment of primary gastric lymphoma and factors that influence the prognosis].

Twenty-two cases of primary gastric lymphoma have been clinicopathologically reviewed and factors influences the prognosis were examined. An increased tumor size of more than 10 cm, an increased tumoral penetration, a lymph node involvement, and stage IV classification decreased the survival rates. All patients given stage I classification have remained alive without having received chemotherapy. The survivors of stages III & IV amounted to only three patients who were treated by surgery and systemic chemotherapy. A radical operation is the choice of treatment for a gastric lymphoma but aggressive chemotherapy should be supplemented for advanced cases.

Adult↗
PubMed1988

[Obstructive sleep apnea syndrome with reversible interventricular septal displacement during sleep: a case report].

A case of the obstructive sleep apnea syndrome revealed reversible leftward displacement of the interventricular septum by echocardiography during sleep. A 46-year-old housewife with congenital micrognathia was admitted to our hospital complaining of severe dyspnea and general edema. On admission, she had severe hypoxemia (PaO2 = 35.2 mmHg), pulmonary hypertension (mean pulmonary artery pressure = 70 mmHg) and right heart failure. Her echocardiograms revealed enlargement of the right ventricle with a flattened left ventricle. A sleep study performed after partial resolution of her right heart failure disclosed that severe hypoxemia and pulmonary hypertension (mean pulmonary artery pressure = 70 mmHg) occurred after relatively long periods of apnea. With vigorous inspiratory efforts during sleep apnea, transient enlargement of the right ventricle and leftward displacement of the septum causing the flattened left ventricle were observed echocardiographically. A concomitant decrease in left ventricular inflow velocities was also observed by the pulsed Doppler method. However, these findings immediately returned to normal with the resumption of ventilation. We concluded that these repetitive apneic events due to obstruction of the airway during sleep might accelerate complete eventual pulmonary hypertension and right heart failure.

Echocardiography↗
PubMed1988

[A case of early gastric cancer forming a large abdominal tumor from a lymph node metastasis].

A 37-year-old male was admitted to our hospital because of an abdominal tumor, about the size of a fist, located anterior to the pancreas head. This tumor oppressed the antrum of the stomach to the left, and an operation was performed, the tumor being diagnosed as a leiomyosarcoma of the stomach, determined from image findings. After histopathological examination, however the tumor proved to be an adenocarcinoma. An early gastric cancer was found at the anterior wall of the antrum during the operation, and the tumor was thought to be a metastatic lymph node. Lymph node metastasis also was observed at the root of the mesentery.

Adenocarcinoma↗
PubMed1988

[Enzyme immunological measurement of estrogen receptors in the human endometrium by the use of monoclonal antibody].

The concentrations of cytosol (ERc), nuclear (ERn), and total (ERc+n) estrogen receptors were determined by Enzyme Immunoassay using Monoclonal Antibody, in normal endometrium freshly obtained from 13 cases, and were compared with those determined by a conventional ligand binding assay on LH-20 (LH-20 assay). There was good correlation between EIA and LH-20 values. The correlation coefficients for ERc, ERn and ERc+n were 0.960, 0.980 and 0.950, respectively. Regression lines were as follows; Ec = 1.22Lc-4.07, En = 1.18Ln+37.7 and Ec+n = 1.27 Lc+n-158.4. These results clearly demonstrate the applicability of the ER-EIA for the determination of estrogen receptors in the endometrium. Particularly for clinical laboratory purposes, the enzyme immunoassay has some advantages over the conventional binding assay in terms of non-radioactivity and simple procedure.

Adult↗
PubMed1987

Characteristics of memory impairment following lesioning of the basal forebrain and medial septal nucleus in rats.

Memory impairment in rats with lesions of the basal forebrain (BF) and medial septal nucleus (MS) including cell bodies of the cortical and septohippocampal cholinergic systems, respectively, were compared in order to evaluate the functional contribution of the two cholinergic systems to memory. Biochemical assay revealed that lesioning of the BF and MS resulted in marked and selective decreases in both choline acetyltransferase and acetylcholinesterase activities in the cerebral cortex and hippocampus, respectively. Rats with BF lesions exhibited a severe deficit in a passive avoidance task; acquisition of passive avoidance by repeated training was sluggish, and the acquired response was rapidly eliminated in a subsequent extinction test. However, only slight impairment of passive avoidance was observed in rats with MS lesions. Memory impairment in rats with BF or MS lesions was also investigated using two spatial localization tasks, the Morris water task and the 8-arm radial maze task. Both BF and MS lesions elicited a significant impairment in the Morris water task that required reference memory, as demonstrated by an apparent increase in the latency to escape onto a hidden platform in a large water tank. The impairment was much more obvious in the BF-lesioned rats. In contrast, in the radial maze task primarily requiring working memory, rats with lesions of the MS showed severe disruption, exhibiting a marked increase in total errors, a decrease in the number of initial correct responses, and an apparent change in the strategy pattern. However, corresponding changes in the rats with BF lesions were slight. These results suggest that BF lesions may lead to substantial long-term memory impairment while MS lesions may primarily produce short-term or working memory impairment, indicating a qualitatively different contribution of the two cholinergic systems to memory. It is also suggested that these two experimental animal models may be useful for evaluation of therapeutic drugs for senile dementia of the Alzheimer type.

Acetylcholinesterase↗
PubMed1987

Atrial natriuretic polypeptide (ANP) in the development of spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP).

In order to investigate the pathophysiological role of atrial natriuretic polypeptide (ANP) in genetic hypertensive rats, the atrial content and plasma concentration of ANP were measured by a sensitive radioimmunoassay (RIA) for rat ANP in 5-, 10- and 20-week-old spontaneously hypertensive rats (SHR) and stroke-prone SHR (SHRSP) and compared to age-matched Wistar Kyoto rats (WKY). Atrial content of immunoreactive ANP (ir-ANP) tended to be higher in SHR and was already significantly higher in SHRSP than in WKY at 5 weeks of age. Atrial content in the hypertensive strains became significantly higher than in WKY when hypertension developed at 10 and 20 weeks. On the other hand, plasma ir-ANP in SHR was significantly lower than in WKY at 5 weeks, however, it became significantly higher in both SHR and SHRSP than in WKY at 10 and 20 weeks. These findings suggest that ANP release may increase to compensate for the elevation of blood pressure in SHR and SHRSP and that biosynthesis of ANP may be concomitantly stimulated, resulting in an increase in atrial ANP.

Aging↗
PubMed1987

Modulation of brain progestin and glucocorticoid receptors by unsaturated fatty acid and phospholipid.

In an attempt to learn how nonsteroidal factors modulate brain progestin and glucocorticoid receptors, the effects of saturated and unsaturated fatty acids, and phosphatidylinositol on the binding of [3H]R5020 or [3H]dexamethasone, determined by sucrose density gradient and gel filtration on LH20, were examined in the cerebral cortical cytosol from 10-day-old female rats which contain a considerable amount of progestin and glucocorticoid receptors. Unsaturated fatty acids such as oleic (C18:1), arachidonic (C20:4) and docosahexaenoic acid (C22:4) depressed the [3H]R5020 or [3H]dexamethasone binding in increasing order, but saturated fatty acids had no effect. Arachidonic and docosahexaenoic acids, which were strong inhibitors, lowered the binding dose dependently. The fatty acid inhibition on brain progestin and glucocorticoid receptors was thus a function of acid dose and degree of acid unsaturation. Interestingly, prostaglandin D2 did not show any effect. Among phospholipids tested the inhibitory effect of phosphatidylinositol on the [3H]R5020 binding was evident, but no significant effect was found with phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine or sphingomyelin. The phosphatidylinositol inhibition was dose dependent. Analysis on kinetics and Scatchard plot have revealed the noncompetitive type of inhibition by arachidonic acid and phosphatidylinositol. From these results it is suggested that the unsaturated nonestrified fatty acid, arachidonic acid, and phosphoinositides modulate the brain progestin and, possibly, glucocorticoid receptors through their binding at sites different from steroid binding sites on the respective receptor molecules.

Animals↗