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M Shimizu

Publications and source records attributed to M Shimizu.

At least 469 records · Page 26Linked to original sources
PubMed1998

Retinoic acid increases in the retina of the chick with form deprivation myopia.

We previously reported that expression of retinoic acid receptor beta increases in the sclera of the 2-week-old chick with form deprivation myopia (FDM) and that all-trans-retinoic acid (t-RA) influences proliferation and differentiation of scleral cells. The purpose of this study was to quantify t-RA in the retina of the chick with FDM and to investigate the role of t-RA in FDM in the chick. FDM was induced in 2-day-old chicks by placement of a translucent plastic goggle over one eye, with the contralateral eye used as a control. After 5 days, the chicks were sacrificed. t-RA was extracted from neural retina and served for high-performance liquid chromatography analysis. 3H-t-RA was used for normalization. Pieces of the retinae from 5 eyes served as one sample. As a result, t-RA was 09.60 +/- 0.86 ng/eye (0.387 +/- 0.056 ng/mg protein) in the myopic retina was significantly higher than that in the control (p < 0.05, n = 7). These results demonstrate that t-RA increases in the retina within 5 days after visual deprivation. This finding suggests that t-RA may play a role in the metabolic changes in FDM.

Animals↗
PubMed1998

Purification, characterization, and cloning of enamel matrix serine proteinase 1.

The maturation of dental enamel succeeds the degradation of organic matrix. Inhibition studies have shown that this degradation is accomplished by a serine-type proteinase. To isolate and characterize cDNA clones encoding this proteinase, we used two degenerate primer approaches to amplify part of the coding region using polymerase chain-reaction (PCR). First, we purified the proteinase from porcine transition-stage enamel matrix and characterized it by partial protein sequencing. The enzyme was isolated from the neutral soluble enamel extract by successive ammonium sulfate precipitations, hydroxyapatite HPLC, reverse-phase HPLC, DEAE ion exchange, and affinity chromatography with a Benzamidine Sepharose 6B column. The intact protein and lysylendopeptidase-generated cleavage products were characterized by amino acid sequence analyses. Degenerate oligonucleotide primers encoding two of the polypeptide sequences were synthesized. In a complementary strategy, degenerate oligonucleotide primers were designed against highly conserved active-site regions of chymotrypsin-like proteinases. Both approaches yielded PCR amplification products that served as probes for screening a porcine enamel organ epithelia-specific cDNA library. The longest full-length clone is 1133 nucleotides and encodes a preproprotein of 254 amino acids. We designate this protein enamel matrix serine proteinase 1 or EMSP1. The active protein has 224 amino acids, an isotope-averaged molecular mass of 24.1 kDa, and an isoelectric point of 6.0. Multiple-tissue Northern analysis indicates that EMSP1 is a tooth-specific protein. Gelatin enzymography shows a dramatic increase in EMSP1 activity in the transition-stage enamel matrix. EMSP1 is most homologous to kallikriens and trypsins.

Amelogenesis↗
PubMed1998

Isolation of a major metabolite (i-OHAP) of aprindine and its identification as N-[3-(N,N-diethylamino)propyl]-N-phenyl-2-aminoindan-5-ol.

i-OHAP, a major metabolite of aprindine (AP), was isolated by TLC from rat feces and identified as N-13-(N,N-diethylamino)propyl]-N-phenyl-2-aminoindan-5-ol, based on 1H-NMR, the H-H correlation spectroscopy (COSY) spectrum, MS and LC-MS. Its structure was also confirmed by comparison with the synthesized compound. The hydroxy group of i-OHAP was located at the 5-position of the indan ring. AP is a prochiral compound, and the metabolism of AP to i-OHAP was stereoselective. The ratio of (+)/(-)-i-OHAP in rat feces and in human urine was about 5 and 15, respectively.

Adult↗
PubMed1998

123I-MIBG SPECT of Merkel cell carcinoma.

131I-MIBG may be useful in the detection of neuroendocrine tumours. Merkel cell carcinoma is a neuroendocrine tumour of the skin. We evaluated a patient with Merkel cell carcinoma using 123I-MIBG single photon emission computed tomography (SPECT) which demonstrated tumour accumulation of the radiotracer in the right eyelid. This result suggests that 123I-MIBG SPECT may be useful in the evaluation of Merkel cell carcinoma.

3-Iodobenzylguanidine↗
PubMed1998

Effects of beta-lactoglobulin on the tight-junctional stability of Caco-2-SF monolayer.

The mechanisms for tight-junction (TJ) stabilization by beta-lactoglobulin (beta-Lg) were studied. Treatment of Caco-2-SF cells with inhibitors for some enzymes in the intracellular signal transduction pathways and a cytoskeleton-disturbing agent (cytochalasin D) reduced the TJ-stabilizing activity of beta-Lg. So beta-Lg is suggested to modulate the cytoskeletal structure through the activation of phospholipase C and protein kinase C, resulting in the TJ stabilization.

Animals↗
PubMed1998

[Improvement of insulin sensitivity after renal transplantation measured by a glucose clamp technique].

There is much evidence indicating that indicates end-stage renal failure induces insulin resistance. We examined the effects of renal transplantation on insulin resistance with an insulin clamp technique. Insulin sensitivity and insulin secretion rates were measured in 13 renal transplant patients, 7 hemodialysis patients, and 6 healthy controls. Insulin sensitivity was assessed with the euglycemic insulin clamp technique. The clamp was applied for 120 minutes and the average of the glucose disposal rates measured from 90 to 120 minutes was regarded as insulin sensitivity. There was a significant increase in the glucose disposal rate in the renal transplantation patients (6.67 +/- 1.44 mg/kg/min) compared to the hemodialysis patients (4.54 +/- 1.44 mg/kg/min) (p < 0.05). Also, there was a significant decrease in the glucose disposal rates in the hemodialysis patients (4.45 +/- 1.44 mg/kg/min) compared to the healthy controls (7.25 +/- 2.07 mg/kg/min) (p < 0.05). There was no significant difference in the glucose disposal rates between the renal transplant patients and the healthy controls. However, patients treated with beta-blockers had lower glucose disposal rates compared to patients without beta-blockers (4.67 +/- 1.58 vs 6.67 +/- 1.44 mg/kg/min, p < 0.05). In this study, we found that insulin resistance, shown by the euglycemic insulin clamp technique, was recovered after successful renal transplantation that but, beta-blockers affected insulin resistance. In conclusion shows that, the hyperglycemic clamp technique, although many factors such as medication may affect insulin sensitivity, renal transplantation restores insulin resistance found in renal failure patients, but not insulin secretion.

Adult↗
PubMed1998

Acute terminal pancreatitis occurring in jejunal heterotopic pancreas.

CONCLUSION: We report a unique case of acute terminal pancreatitis occurring in the jejunal heterotopic pancreas. Unlike previously reported cases, acute pancreatitis was not found histologically in the ordinary pancreas. BACKGROUND: Heterotopic pancreas may show the same inflammatory or neoplastic changes, such as acute pancreatitis and adenocarcinoma, as those that occur in the ordinary pancreas. However, histologically proven acute pancreatitis occurring in heterotopic pancreas is very rare and only three reports have been described. METHODS: A 53-yr-old Japanese man died of hepatic failure, and autopsy was performed. RESULTS: Autopsy incidentally revealed heterotopic pancreas of the jejunum. Microscopically, focal acute pancreatitis was observed in the jejunal heterotopic pancreas, whereas the pancreas of the normal location showed no abnormality. In addition, no clinical evidence of pancreatic disease was noted before death. Therefore, we diagnosed this case as acute terminal pancreatitis occurring in the jejunal heterotopic pancreas.

Acute Disease↗
PubMed1998

Collagen synthesis by cultured cardiac fibroblasts obtained from cardiomyopathic hamsters.

The aim of the present study was to clarify myocardial collagen metabolism in cardiomyopathic hamsters and the effects of the angiotensin converting enzyme inhibitor, captopril, on collagen synthesis. Cardiac fibroblasts from Bio 14.6 cardiomyopathic hamsters and from non-cardiomyopathic Flb hamsters were cultured and used in the 4th passage. The synthetic activity of collagenous protein from the two types of hamsters was determined by measuring 3H-proline uptake, and the collagen type was subsequently analyzed by SDS-PAGE in cultured cardiac fibroblasts. Also studied were the effects of the angiotensin converting enzyme inhibitor captopril (1 microM) on collagen synthesis by cardiac fibroblasts from cardiomyopathic hamsters. Twenty five-week-old Bio 14.6 hamsters had significantly higher synthetic activity of collagenous protein and rate of collagen synthesis compared with 13-week-old Bio 14.6 hamsters or 25-week-old Flb hamsters [Bio 14.6(25-week); 12.4 +/- 1.6, Bio 14.6(13-week); 4.8 +/- 0.4, Flb (25-week); 8.7 +/- 0.9 cpm/cell, Bio 14.6(25-week); 11.0 +/- 0.9, Bio 14.6(13-week); 3.9 +/- 0.4, F1b (25-week); 4.8 +/- 0.4%, p < 0.05]. Qualitatively, 25-week-old Bio 14.6 hamsters had significantly higher synthetic activity of type I, III, IV and V collagens compared with 25-week-old F1b hamsters. The synthetic activity of type III collagen was increased the most in the cardiomyopathic group. Captopril (1 microM) caused a significant decrease in synthetic activity of collagenous protein in 25-week-old Bio 14.6 hamsters (12.4 +/- 1.6 cpm/cell-->10.9 +/- 1.1 cpm/cell, p < 0.05). Qualitatively, the synthetic activity of type III collagen was decreased to about half. Our study revealed enhanced collagen synthetic activity in cardiac fibroblasts from Bio 14.6 hamsters. Captopril improved collagen metabolism in cultured cardiac fibroblasts from Bio 14.6 hamsters not only quantitatively but also qualitatively. The mechanism of this improvement may be related to the cardiac renin angiotensin system.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Sites of asparagine-linked oligosaccharides in porcine 32 kDa enamelin.

The 32 kDa enamelin protein isolated from developing porcine enamel was previously shown to contain eight different asparagine-linked oligosaccharides. However, only three consensus attachment sites were evident in this protein. In this study, glycopeptides containing all three potential glycosylation sites (72-Asn, 79-Asn and 91-Asn) were purified from 32 kDa enamelin. The oligosaccharides were isolated from each glycopeptide following digestion with N-oligosaccharide glycopeptidase, labeled with 2-aminopyridine at the reducing ends, and then characterized by reverse phase HPLC. All three potential sites were found to be glycosylated heterogeneously (i.e., five biantennary complexes at 72-Asn, two biantennary complexes at 79-Asn, three triantennary complexes at 91-Asn), accounting for all eight oligosaccharides characterized previously. These results indicate that 32 kDa enamelin has a complex pattern of asparagine-linked glycosylation localized within a small region (20 residues) of the protein. The functional significance of this glycosylation remains to be established.

Animals↗
PubMed1998

Characterization of thiamin-binding protein from buckwheat seeds.

A thiamin-binding protein from buckwheat (Fagopyrum esculentum Moench) seeds gave two bands of 56-and 50-kDa in the absence of 2-mercaptoethanol and a single band of 25-kDa in the presence of 2-mercaptoethanol on sodium dodecylsulfate gel electrophoresis. These results indicate that the protein consists of polypeptides linked by disulfide bond(s). The protein isolated from buckwheat seeds did not have immunological homology with the thiamin-binding proteins from rice seeds and sesame seeds. However, the binding of the protein to thiamin was inhibited by the modification of the carboxyl residues in the protein as well as that of the thiamin-binding protein from rice seeds. These results suggest that the thiamin-binding protein from buckwheat seeds differ from those from rice seeds and sesame seeds as to subunit structure or immunological properties, but resembles them in the mechanism of binding thiamin.

Carrier Proteins↗
PubMed1998

Thiamin-binding protein from sunflower seeds.

A thiamin-binding protein was isolated from sunflower seeds. Its molecular mass was estimated to be 230 kDa by gel filtration. The protein was suggested to be composed of six subunits, which consisted of polypeptides linked by disulfide bond(s). The protein contained a large amount of glutamine or glutamic acid (19.9 mol%) and asparagine or aspartic acid (11.1 mol%). The levels of tryptophan and valine in the protein were low. These properties of the thiamin-binding protein were similar to those of helianthinin. Optimum pH for the thiamin-binding activity of the protein was 8.0 to 9.0. The thiamin-binding activity was not inhibited by thiamin monophosphate, thiamin pyrophosphate, oxythiamin, or pyrithiamin. These properties of the thiamin-binding protein from sunflower seeds were similar to those from buckwheat seeds, but not to those from rice seeds and sesame seeds.

Asparagine↗
PubMed1998

Development and evaluation of regional health database systems.

We have developed information systems for regional public health in some areas. These systems have the following functions: (1) to register results of examinations, life style, follow-up data, diseases, (2) to output some reports and statistics for daily jobs, (3) to make a personal health database, (4) to display stored data by character, trend graph, radar chart or bar chart, (5) to analyze regional health problems, (6) to extract dada about persons with some conditions, (7) to compare data among some examinations, (8) to analyze risk factors. Each database can be transferred to mini-notebook type personal computers. So, they can be used anywhere and any time. Some access controls are performed for security. The systems are used in routine works, health consultation for persons and health education for groups. We have evaluated the systems and got some useful results. Using the systems, daily jobs can be performed with good accuracy and less labor, each subject can understand one's health status easily and clearly, grasps of health problems can be made quantitatively and health projects can be planned by scientific methods.

Aged↗
PubMed1998

Radiotoxicity after iodine-131 therapy for thyroid cancer using the micronucleus assay.

UNLABELLED: The purpose of the present study was to evaluate the degree of cytological radiation damage to lymphocytes after 131I therapy using the cytokinesis-blocked micronucleus assay. The chromosomal damage to lymphocytes induced by 131I in vivo should result in augmentation of the cells with micronuclei. METHODS: We studied 25 patients with differentiated thyroid carcinoma who were treated with 3.7 GBq of 131I. Isolated lymphocytes collected from patients 1 wk after therapy were harvested and treated according to the cytokinesis-blocked method of Fenech and Morley. The micronucleus number of micronuclei per 500 binucleated cells were scored by visual inspection. As controls, lymphocytes from the same patients before therapy were also studied. In an in vitro study, lymphocytes from three patients at least 3 mo after therapy were exposed to doses varying from 0.25 to 1 Gy and studied with the same method. RESULTS: The mean number (mean +/- s.d.) of micronuclei after treatment was significantly increased (p < 0.05) as compared to control subjects (15.7 +/- 2.7 vs. 5.4 +/- 1.4). Since there was an interval ranging from 6 to 20 mo (mean 11.8 mo) between the present and the last radioiodine therapy, no significant effect on the frequency of micronucleus with cumulative radiation exposure of 131I to lymphocytes was detected. Internal radiation absorbed doses estimated for 25 patients were 0.33 +/- 0.09 Gy in this external irradiation study. CONCLUSION: The relatively low frequency of lymphocyte micronuclei induced by 131I in vivo and lack of significant effect on the frequency of lymphocyte micronuclei with cumulative 131I supported the contention that short-term nonstochastic damage of this therapy with 3.7 GBq of 131I in thyroid cancer patients is minimal and reversible.

Female↗
PubMed1998

Negative regulation of the rat cdc2 promoter in G1 by the silencer element.

Expression of the cdc2 gene is induced steeply at the G1-S-phase boundary. The previous analysis of promoter elements that confer inducibility revealed the enhancer at positions -276 to -265. Enhancer activity is suppressed by the upstream sequence that seems to contain the silencer. The silencer element was analyzed by fusing several oligonucleotides covering the silencer region upstream of the enhancer in the cdc2 promoter-luciferase construct. Oligonucleotide IV, which suppressed enhancer activity, was further dissected by the introduction of base substitutions and by forming the DNA-protein complexes with quiescent rat cell extract. The silencer element, AAGTAGTAAAAATA, was finally identified at positions -374 to -360, which resembles the enhancer sequencer but contains extra internal AG residues. Silencer complexes were formed with the quiescent cell extract, whereas the amounts of the complexes decreased with the progression of the cell cycle, and nearly no complexes were formed with the late G1 cell extracts. Conversely, the enhancer complex begins to be formed after late G1. Among the three silencer complexes, the formation of the slowest-migrating complex (complex III) was inhibited by the enhancer sequence, suggesting that a common factor interacts with both the silencer and enhancer. These results suggest that the conversion of complex formation from the silencer to the enhancer site regulates the induction of cdc2 promoter activity at the G1-S-phase boundary.

Animals↗
PubMed1998

[Postoperative respiratory disturbance after anterior cervical fusion].

We examined 171 patients who had undergone anterior cervical fusion to determine the frequency and the causes of postoperative respiratory disturbance (PRD). Postoperative tracheal intubation was necessary in 11 patients (6.4%), but only 4 of them (2.3%) required reintubation due to PRD caused by surgical procedures. PRD has been reported to occur at various frequencies in previous studies, partly due to unsettled criteria of PRD, miscellaneous primary diseases, and heterogeneous surgical procedures. As C 3 was fused in the 4 patients with PRD, requiring reintubation, upper airway obstruction due to serious swelling of the soft tissue surrounding C 3 might be the factor leading to postoperative reintubation. One of the PRD patients who suffered from postoperative unilateral phrenic nerve palsy required controlled ventilation.

Adult↗