Biomedical subjects

M Shimizu

Publications and source records attributed to M Shimizu.

At least 703 records · Page 39Linked to original sources

PubMed1995

Expression of a cell adhesion molecule, neuropilin, in the developing chick nervous system.

Neuropilin (previously known as the A5 protein) is a membrane protein identified in Xenopus and is presumed to be involved in the target recognition of the optic nerve fibers. We have isolated cDNAs encoding the chick homologue of neuropilin, using the Xenopus neuropilin cDNA as a hybridization probe. The predicted amino acid sequence of chick neuropilin is 75% identical to that of the Xenopus homologue. A cell aggregation assay showed that fibroblasts transfected with the chick neuropilin cDNA acquired cell adhesiveness. This adhesion is mediated by a heterophilic interaction between neuropilin and protease-sensitive molecules on fibroblasts. The expression of chick neuropilin is restricted to certain neuronal circuits and is dynamically regulated during development, as is the Xenopus homologue. However, their expression patterns differed significantly in the visual systems between the two species: In the chick optic tectum, the localization of neuropilin is confined to layers d and e of SGFS, two of the six layers receiving the retinal input; the chick optic nerve fibers do not express neuropilin; in the chick retina, amacrine cells transiently express neuropilin. Cultured neurons of the dorsal root ganglia express chick neuropilin on their neurites including growth cones. These results suggests that neuropilin functions as a cell adhesion molecule during the formation of certain neuronal circuits in vivo.

3T3 Cells↗

PubMed1995

Forced expression of YL-1 protein suppresses the anchorage-independent growth of Kirsten sarcoma virus-transformed NIH3T3 cells.

The YL-1 gene, encoding a novel nuclear protein with transcription factor-like features, has been isolated from the human chromosome 1q21, one of the regions supposedly carrying a transformation suppressor gene(s) for Kirsten sarcoma virus-transformed NIH3T3 (DT) cells. To test the suppressive activity of the YL-1 gene product, we forced the expression of human YL-1 cDNA in DT cells. The anchorage-independent growth (colony-forming ability in soft agar medium) was markedly suppressed in cells highly expressing the exogenous human YL-1 protein. Moreover, the soft agar clones, which were rarely originated from these cells, expressed reduced levels of exogenous YL-1 or none, with or without the loss/rearrangement of the introduced cDNA. In control experiments, cells carrying an introduced vector alone or an antisense-strand expression plasmid grew in soft agar as efficiently as parental DT cells. In contrast to the suppression of anchorage-independent growth, the forced expression of YL-1 did not effect the transformed phenotypes in adherent culture and tumorigenicity in nude mice. These findings not only indicated that the YL-1 protein functions as a transformation suppressor, but also suggest that it may be important for elucidating anchorage independence under separate genetic control from other transformed phenotypes.

3T3 Cells↗

PubMed1995

The adverse effects of oral 2-mercaptobenzimidazole on pregnant rats and their fetuses.

The effects of oral 2-mercaptobenzimidazole (2-MBI) on pregnant Wistar rats were examined. In a preliminary dose-finding study, pregnant rats treated with 2-MBI over Days 7-17 of gestation showed reduction in maternal thymus weights with compound-related mortality at doses > or = 40 mg/kg. No adverse effects on fetuses were found at doses < or = 40 mg/kg. However, anasarca, cleft palate, and dilated lateral ventricles were present in all fetuses from the only survivor among the dams treated with 60 mg/kg of 2-MBI. In the teratology study, pregnant rats were treated with 2-MBI at doses of 0, 3.3, 10, and 30 mg/kg during the period of organogenesis (Gestation Days 7-17). In addition, pregnant rats of three groups were also treated with 60 mg/kg of 2-MBI for 3 or 4 days during specific periods of organogenesis (Days 7-10, 11-14, or 15-17 of gestation). Treatment on Gestation Days 7-17 resulted in reduced maternal thymus weights at doses of > or = 3.3 mg/kg. In addition to reduced fetal weights, visceral variations (kinked ureter and dilated renal pelvis) and delayed ossification were seen in the fetuses at doses > or = 10 mg/kg, and skeletal variations (rudimentary lumbar ribs) were seen at 30 mg/kg. In the fetuses from the dams treated with 60 mg/kg of 2-MBI, rudimentary lumbar ribs were seen mainly in the group treated on Days 7-10 of gestation, whereas kinked ureter and dilated renal pelvis were evident mainly in the group treated on Gestation Days 15-17.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗

PubMed1995

A comparative study on Langerhans cells in lymph nodes with dermatopathic lymphadenopathy and histiocytosis X cells.

It was elucidated that the majority of DC were LC which were positive for CD 1a, but negative for PCNA, and possessed BG in the lymph nodes with DPL. On the other hand, HCX cells were almost always positive for PCNA. From this point of view, it can be speculated that LC in the lymph nodes of the DPL are non dividing mature cells and migrate from the skin lesion. HCX cells which were positive for CD 4 may be more immature cells than LC in DPL, and may be pathological cells which can divide in the foci.

Antigens, CD1↗

PubMed1995

Endoscopic detection of ectopic multiple minute sebaceous glands in the esophagus. Report of a case and review of the literature.

This case report describes a patient with a rare form of ectopic sebaceous glands. The patient was a 53-year-old woman complaining of prolapse of a polyp through the anus who was admitted for polypectomy of the rectal polyp. After polypectomy, esophagogastroduodenoscopy was performed to detect other lesions. Although she had no symptoms from an upper gastrointestinal series, such as dysphagia, heartburn, or epigastric pain, multiple yellow rounded elevated lesions arranged in rows, 0.5 mm in diameter and more than 100 in number were observed in the middle and lower esophagus. Histological examination of the biopsied specimens taken from the lesions endoscopically revealed a structure with the characteristics of a sebaceous gland including an excretory duct.

Biopsy↗

PubMed1995

Three cases of primary biliary cirrhosis associated with bronchial asthma.

The association of primary biliary cirrhosis (PBC) and bronchial asthma was observed in three patients. All of these patients were female (53, 54, and 41 years old, respectively), and were positive for antimitochondrial antibodies. The patients fulfilled the diagnostic criteria of both PBC and bronchial asthma. Bronchial asthma preceded PBC in two patients, and the reverse order was seen in the other. Patient the clinical symptoms were mainly due to the bronchial asthma. Two patients had asymptomatic PBC and the third patient complained of pruritus. The liver histology showed mild to moderate eosinophilic infiltration in addition to the ductal and hepatic parenchymal changes characteristic of PBC. A survey of 266 cases of PBC referred to us disclosed that, in 6 of these, the PBC was associated with bronchial asthma, while no association with bronchial asthma was the material of found in 166 patients with viral hepatitis in our liver biopsy files. The 3 present cases we experienced suggest that bronchial asthma may be included in the list of extrahepatic diseases associated with PBC. The significance of this association is unclear and may merit further study. Steroid therapy, which is known to cause adverse effects in PBC, was employed for bronchial asthma in these 3 patients. Another therapeutic approach will have to be considered in patients with bronchial asthma associated with PBC.

Adult↗

PubMed1995

Concurrent detection of cholecystocolic fistula and hepatic abscess by hepatobiliary scintigraphy.

We report the case of a 58-year-old male with cholecystocolic fistula and hepatic abscess that were not diagnosed by routine radiologic examinations, but concurrently detected by hepatobiliary scintigraphy with 99mTc-PMT, and confirmed at operation. Hepatobiliary scintigraphy is noninvasive and useful in the detection of a biliary enteric fistula and lesions about related organs. Concurrent detection of cholecystocolic fistula and hepatic abscess on hepatobiliary series is of great clinical value in planning surgical intervention.

Biliary Fistula↗

PubMed1995

Postgastrectomy osteomalacia with pseudofractures assessed by repeated bone scintigraphy.

A patient with osteomalacia secondary to vitamin D deficiency after gastrectomy for gastric cancer is presented. Initial bone scintigrams showed both asymmetric and symmetric focal areas of intense uptake due to pseudofractures reminiscent of bone metastases. Radiographs only confirmed the presence of pseudofractures at some, but not all, of the abnormal sites demonstrated by bone scintigraphy. At first, metastatic bone disease was suspected. However, the appearance of repeated bone scintigram was normalized after treatment with vitamin D. A diagnosis of osteomalacia was established. The present case serves to illustrate that symmetric focal lesions are important features of pseudofractures secondary to osteomalacia, and comparison with radiographs and repeated bone scintigraphy are necessary in distinguishing between bone metastases and pseudofractures.

Bone Neoplasms↗

PubMed1995

The value of combined 99mTc-Sn-colloid and 99mTc-RBC scintigraphy in the evaluation of a wandering spleen.

Wandering spleen is the term commonly applied to splenic hypermobility that results from laxity or maldevelopment of its suspensory ligaments. It comes to medical attention usually as an abdominal mass, or when the spleen undergoes torsion. Diagnosis on clinical grounds alone is rarely made, and ultrasonography, CT and MRI findings have no specific characteristics for this condition. 99mTc-labeled colloid taken up by the spleen may provide a specific diagnosis. We report a case of wandering spleen, in which the preoperative diagnosis was made on the basis of sequential liver-spleen scintigraphy with 99mTc-Sn-colloid and blood-pool scintigraphy with 99mTc-RBC. This is a rare case, in which hypermobility was assessed by sequential 99mTc-Sn-colloid scintigraphy, and to our knowledge, is the first case in which 99mTc-RBC scintigraphy provided useful information on splenic blood volume and its location.

Adult↗

PubMed1995

Sequential subtraction scintigraphy with 99mTc-RBC for the early detection of gastrointestinal bleeding.

To improve the early detectability of gastrointestinal (GI) bleeding, we have developed a new subtraction scintigraphic technique using in vivo labeled 99mTc red blood cells (RBC). Use of this new sequential subtraction method every 5 min makes it possible to detect early the bleeding site and calculate the bleeding rate. In phantom experiments, focal activity was detected on subtraction images at pump rates of more than 0.20 ml/min at any urethane thickness, but was negative on conventional scintigrams. The calculated pump rate by the subtraction method correlated well with the actual syringe pump rate (y = 1.07x - 0.02, r = 0.99, p < 0.01) in the case of an 8-cm urethane board as an abdominal wall. Twenty-four of 50 patients with suspected GI bleeding were confirmed to be positive within 24 hr. The subtraction method showed 15 true positive and 2 false positive cases within 60 min. On the other hand, the conventional scintigraphic method showed only 7 true positive and 1 false positive cases. Sensitivity of the subtraction method was 62.5%, which was significantly higher (p < 0.05) than that of the conventional scintigraphic method (29.2%). These results suggest that sequential subtraction scintigraphy with 99mTc-RBC is an effective method for the early detection of GI bleeding and shortening the examination time as compared with conventional scintigraphy.

Adolescent↗

PubMed1995

Mutation in the mitochondrial tRNA(leu) at position 3243 and spontaneous abortions in Japanese women attending a clinic for diabetic pregnancies.

Mitochondrial DNA is exclusively maternally inherited. We recently found the prevalence of diabetic patients with an A to G transition at position 3243 of leucine tRNA (3243 base pair (bp) mutation) to be nearly 1% in randomly selected Japanese subjects. Here, we report the higher prevalence of diabetic patients with the 3243 bp mutation in a specific Japanese population of women attending a diabetic pregnancy clinic. Of 102 patients with non-insulin-dependent diabetes mellitus 6 (5.9%) were positive for the mutation, 1 (8.3%) of 12 patients with gestational diabetes and 2 (5.9%) out of 34 borderline diabetic patients. In contrast, none of 64 patients (0%) with insulin-dependent diabetes mellitus had the 3243 bp mutation. Moreover, there was a difference in the prevalence of spontaneous abortions between patients with and without this mutation (27.3 vs 12.4%). Among nine probands with the mutation, four had a history of one spontaneous abortion (p = 0.0518) and two had a history of two abortions (p = 0.0479). Two probands had a spontaneous abortion even while under strict diabetic metabolic control. The 3243 bp mutation thus may cause spontaneous abortion during pregnancy.

Abortion, Spontaneous↗

PubMed1995

Synthesis and biological activity of N-terminal-truncated derivatives of human epidermal growth factor (h-EGF).

To investigate the contribution of the N-terminal sequence of h-EGF to its biological activity and the formation of three intramolecular disulfide bonds by oxidative refolding via air oxidation, five derivatives of h-EGF with a single N-terminal amino acid deletion were synthesized by solid-phase synthesis. The homogeneity of the synthetic peptides was confirmed by analytical reversed-phase HPLC, amino acid analysis, and FAB-MS. The pairing of the three disulfide bridges in synthetic peptides was determined by thermolytic digestion. All N-truncated derivatives of h-FGF formed the correct intramolecular three disulfide linkages during oxidative refolding and had equipotent activity in both EGF receptor binding on A-431 epidermoid carcinoma cells and mitogenesis on NIH-3T3 fibroblast cells, compared with authentic h-EGF. The results suggested that the five residues from N-terminal sequence of h-EGF have no effect on the formation of the correct disulfide linkages in h-EGF and do not exert a significant influence on its biological activity.

3T3 Cells↗

PubMed1995

A mutant of pseudorabies virus with deletion of glycoprotein gIII gene prepared from a Japanese isolate: it fails to agglutinate mouse erythrocytes.

A mutant with deletion of the glycoprotein gIII gene was produced from a Japanese isolate of pseudorabies virus (PrV) and characterized. Viral titers of the mutant propagated in PK-15 cells were always lower than those of the parental virus. The parental virus agglutinated BALB/c mouse erythrocytes, whereas the deletion mutant showed no hemagglutinating activity. Pigs inoculated with the parental virus produced not only neutralizing but also hemagglutination-inhibiting antibodies. On the other hand, the mutant induced high titers of neutralizing antibody comparable to the parental virus but no hemagglutination-inhibiting antibody in inoculated pigs, suggesting that glycoprotein gIII is an essential component for hemagglutination of PrV. Finally, no evidence that the deletion mutant lost virulence for mice was obtained.

Animals↗

PubMed1995

Cytocidal infection of hog cholera virus in porcine bone marrow stroma cell cultures.

Porcine bone marrow stroma cell (BMSC) cultures producing cells of granulocyte-lineage were established. Hog cholera (HC) virus ALD and Alfort strains replicated in the porcine BMSC cultures showing distinct cytopathic effect (CPE). The differentiation of granulocyte-lineage cells in the cultures ceased after infection with HC virus. Polyclonal antibody against the ALD strain inhibited completely the development of CPE of the both ALD and Alfort strains. Monoclonal antibodies (mAbs) specific to the ALD strain inhibited CPE of the ALD strain, while CPE of the Alfort strain was not affected by those mAbs, suggesting that CPE induced in the BMSC cultures is due to HC virus.

Animals↗

PubMed1995

Effects of short-term aminophylline administration on cardiac functional reserve in patients with syndrome X.

OBJECTIVES: This study sought to evaluate the effect of adenosine receptor blockade by aminophylline on cardiac functional reserve in patients with syndrome X. BACKGROUND: Aminophylline may have a potentially antiischemic effect through the inhibition of adenosine and, thus, the coronary steal phenomenon in patients with syndrome X. METHODS: A single-blind, placebo-controlled study of an intravenous infusion of aminophylline (6 mg/kg body weight over 15 min) or placebo (20 ml of saline solution over 15 min) was performed during continuous radionuclide monitoring of left ventricular ejection fraction in 12 patients performing supine bicycle ergometric exercise. RESULTS: Aminophylline increased exercise time (aminophylline 400 s vs. placebo 355 s, p < 0.01), decreased degree of ST segment depression (aminophylline 1.6 mm vs. placebo 2.4 mm, p < 0.01) and either abolished (seven patients) or diminished (five patients) chest pain during exercise. Aminophylline also increased left ventricular ejection fraction at rest (aminophylline 66.5% vs. placebo 62.3%, p < 0.05) but did not improve its deterioration at peak exercise (aminophylline 60.1% vs. placebo 56.6%, p = NS) or shorten the abnormally prolonged interval between the end of exercise and the overshoot (aminophylline 115 s vs. placebo 130 s, p = NS). CONCLUSIONS: Aminophylline infusion increases ischemic threshold and prolongs exercise duration in patients with syndrome X. It is hypothesized that aminophylline acts by inhibiting the coronary steal phenomenon through adenosine receptor blockade. It does not improve the deterioration in left ventricular function at peak exercise or the delayed response in ejection fraction in the recovery period, presumably because the beneficial effects of aminophylline that result from the redistribution of coronary blood flow are limited.

Aminophylline↗

PubMed1995

Increased spontaneous production of IL-8 in peripheral blood monocytes from the psoriatic patient: relation to focal infection and response to treatments.

To evaluate the contribution of peripheral blood monocytes (PBMC) to epidermotropic inflammatory reactions in psoriasis, using an enzyme-linked immunosorbent assay we measured spontaneous interleukin-8 (IL-8) production in PBMC obtained from patients with psoriasis. IL-8 production in the psoriatic PBMC was significantly higher than that in normal control PBMC. Plasma IL-8 levels in psoriatic patients were also moderately increased compared to normal control levels. IL-8 production in PBMC was closely related to the clinical severity of psoriasis and to the response to treatment, including systemic methotrexate (MTX) treatment and tonsillectomy. IL-8 production in PBMC was also positively related to the production of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in these cells. We speculate that the chemotactic cytokine IL-8 contributes to the development of psoriatic skin lesions, and mediates inflammatory reactions from the inflammatory focus to the psoriatic lesions.

Adolescent↗

PubMed1995

Bellidifolin stimulates glucose uptake in rat 1 fibroblasts and ameliorates hyperglycemia in streptozotocin (STZ)-induced diabetic rats.

Bellidifolin, isolated from Swertia japonica, was found to be a potent hypoglycemic agent in STZ-induced diabetic rats by both oral and intraperitoneal administration. Bellidifolin significantly lowered the loaded glucose level in normal as well as diabetic rats. Bellidifolin also lowered blood triglyceride levels significantly. It stimulated glucose uptake activity in Rat 1 fibroblasts expressing human insulin receptors.

Animals↗

PubMed1995

Specific aminoacylation of C4N hairpin RNAs with the cognate aminoacyl-adenylates in the presence of a dipeptide: origin of the genetic code.

A series of C4N hairpin RNAs bearing anticodon nucleotides at the 5' ends and a discriminator base and the sequence CCA at the 3' ends was constructed by an in vitro transcription system using T7 RNA polymerase. These RNAs were aminoacylated specifically with their cognate amino acids by reaction with aminoacyl-adenylates in the presence of a dipeptide, valyl-aspartic acid, suggesting that such hairpin RNAs are able to play the role of the present-day tRNA and that valyl-aspartic acid can perform the function of the present-day aminoacyl-tRNA synthetase as a catalyst in the aminoacylation reaction. These results should provide a useful clue to elucidating the origin of the genetic code.

Adenosine Monophosphate↗