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Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 127 records · Page 7Linked to original sources
PubMed1997

Concentration-dependent changes in motor behavior produced by continuous intrathecal infusion of excitatory amino acids in the rat spinal cord.

A growing body of evidence has suggested that glutamate receptors mediate selective degeneration of neurons in the central nervous system during the development of neurodegenerative diseases. Glutamate receptors are divided into N-methyl-D-aspartate (NMDA)-type and non-NMDA-type. Neurotoxicity mediated by the latter has attracted much interest as a possible causative mechanism underlying amyotrophic lateral sclerosis (ALS). As the clinical course of ALS is chronic and progressive, investigation of chronic effects of non-NMDA receptor agonists on neuronal function would be useful for evaluating the role of glutamate receptor-mediated neurotoxicity in ALS. However, chronic non-NMDA receptor-mediated neurotoxicity has been investigated less thoroughly than acute neurotoxicity. We infused an aqueous solution of R,S-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) intrathecally and continuously by an osmotic minipump in rats. This method of continuous infusion enabled us to keep the drug concentration relatively constant in the cerebrospinal fluid surrounding the spinal cord. The present method of AMPA administration is more suitable for investigating ALS pathogenesis than acute injections, in view of the gradual progression of the disease and the selectivity of lesions produced.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1997

Rehabilitation of spinal cord injury in the national rehabilitation center for the disabled of Japan: profile of a spinal service.

The National Rehabilitation Center for the Disabled (hereunder abbreviated NRC) in Japan was established in 1979. It consists of four divisions: the hospital, the rehabilitation training center, the research institute, and the information service section. The spinal unit has been functioning and cooperating corelatively with all of these divisions. There were 1047 patients with a spinal cord injury treated in the 15 years from September, 1980 to August, 1994; consisting of 924 males (88.3%), and 123 females (11.7%). The breakdown of causes of injury were traffic accidents 44.9%, having a fall 14.7%, sports accidents 6.7%, and other causes of spinal paralysis 10.5%. The sites of the spinal cord lesions were cervical 372 (35.5%), thoracic 547 (52.5%), and lumbar spinal cord 128 patients (12.3%). The incidence of complete paralysis in those with a cervical spinal cord injury (SCI) was 68.8%, and for thoracic and lumbar SCI 79% each. The time for completion of activities of daily living (ADL) was 12.0 +/- 1.54 months in those with tetraplegia, and 5.6 +/- 1.71 months for those with paraplegia. The rate of employment for reentry into society was 59% in those with a cervical spinal cord injury, and 74% each in those with a thoracic or lumbar spinal cord injury.

Adolescent↗
PubMed1997

Onset of coronary artery disease prior to initiation of haemodialysis in patients with end-stage renal disease.

To determine whether the onset of coronary artery disease may precede the initiation of dialysis in patients with end-stage renal disease, we performed coronary angiography within 1 month of initiation of maintenance haemodialysis in 24 patients (age range 42-78 years; mean 63.7 +/- 11). Coronary angiography was performed regardless of the absence or presence of angina. Fifteen patients had diabetic nephropathy, and nine had non-diabetic nephropathy. Significant coronary stenosis was defined as at least 75% narrowing of the reference segment. Fifteen patients (62.5%) with a total of 49 lesions were classified as the coronary artery disease present group. Eleven of those 15 (73.3%) had multivessel disease. The average number of stenotic lesions was 3.3 per patient. The most common patterns of stenosis were complex (23 lesions; 47%), and diffuse lesions over 20 mm long (14 lesions; 29%). None of the clinical or haematological factors evaluated differed significantly between the groups with and without coronary artery disease. The prevalence of coronary artery disease was 72.7% in the symptomatic patients and 53.8% in the asymptomatic patients. The diagnosis of coronary artery disease at the start of maintenance haemodialysis based only on chest symptoms and clinical factors proved to be difficult. Coronary angiography is thus essential for evaluating coronary artery disease in uraemic patients. Many patients with end-stage renal disease had coronary artery disease prior to the start of haemodialysis.

Adult↗
PubMed1997

Severity of neurological disorders in elderly residents of a farming town in Kyushu, Japan; prevalence of disability in activities of daily living.

Activities of daily living (ADL) were evaluated in 421 elderly people, aged 60-95, who resided in 27 randomly selected communities in the town of Mifune, Japan. The disability of ADL increased with age, and was particularly rapid after age 80. Most of the elderly were independent; the prevalence of dependent elderly ranged from 0.7% (in feeding) to 9.5% (in working). The prevalence of dependent elderly increased markedly after age 80 in all ADL items, especially those related to behavior such as ambulation, stair climbing, transfers, and working (i.e., employment, housekeeping, etc.). These results emphasize the importance of community health care of the elderly for preventing and treating neurological disorders which comprised the main cause of disabilities of behavioral ADL.

Activities of Daily Living↗
PubMed1997

[Does physical status influence the axillary temperature among junior high-school students?].

The relationship between physical status and axillary temperature was examined in 373 junior high-school students. Axillary temperature was measured with a mercury glass thermometer, twice a day (8:15, 15:45) for a week, 10 minutes taken for each measurement. In addition, body mass index (BMI) was calculated from weight and height. And the subjects were divided into two groups according to the mean value of BMI (19.20 [kg/m2]), i.e., the low BMI group (LB) and the high BMI group (HB). We then compared the axillary temperature between LB and HB. The temperature both in the morning and afternoon was significantly lower in the HB than in the LB (p < 0.01, p < 0.05). In conclusion, a high BMI was associated with a decrease in axillary temperature in junior high-school students.

Adolescent↗
PubMed1996

Reduction of 14-16 kDa allergenic proteins in transgenic rice plants by antisense gene.

An antisense gene strategy was applied to suppress the 14-16 kDa allergen gene expression in maturing rice seeds. Gene constructs producing antisense RNAs of the 16 kDa allergen under the control of some rice seed-specific promoters were introduced into rice by electroporation. Immunoblot and RNA blot analyses of the seeds from the transgenic rice plants using the allergen-specific monoclonal antibody and a sequence-specific antisense RNA probe demonstrated that the 14-16 kDa allergen proteins and their transcripts of the seeds from several transgenic lines were present in much lower in amounts than those of the seeds from parental wild-type rice. The high levels of reduction observed were stably inherited in at least three generations.

Allergens↗
PubMed1996

Cloning of the rice seed alpha-globulin-encoding gene: sequence similarity of the 5'-flanking region to those of the genes encoding wheat high-molecular-weight glutenin and barley D hordein.

A genomic clone encoding the rice endosperm major globulin (alpha-globulin) with an apparent molecular mass of 26 kDa was isolated, and its nucleotide (nt) sequence and transcription start point (tsp) were determined. The tsp was identical to that of the gene encoding the wheat high-molecular-weight (HMW) glutenin subunit. The consensus '-300 element' and an A + T-rich sequence exist upstream from the TATA box in the 5'-flanking region. A nt sequence of about 130 bp in the 5'-flanking region was found to be markedly homologous to those of the genes encoding the wheat HMW glutenin subunit and barley D hordein.

Alpha-Globulins↗
PubMed1996

An SH3 domain-mediated interaction between the phagocyte NADPH oxidase factors p40phox and p47phox.

The phagocyte NADPH oxidase is activated during phagocytosis to produce superoxide, following assembly of a membrane-integrated cytochrome b558 with cytosolic proteins, p47phox, p67phox and p40phox, each containing Src homology 3 (SH3) domains. While both p47phox and p67phox are indispensable for the oxidase activity, role of p40phox remains obscure. Here we study interaction between p40phox and p47phox by two independent methods, a two-hybrid system in the yeast and an in vitro binding assay using purified proteins. The present results show that the interaction is mediated via binding of the SH3 domain of p40phox to a C-terminal proline-rich region of p47phox. This proline-rich region is also the target for binding of p67phox, and the SH3 domain of p40phox can inhibit the binding of the C-terminal one of p67phox to p47phox.

Amino Acid Sequence↗
PubMed1996

The same nuclear proteins bind to the 5'-flanking regions of genes for the rice seed storage protein: 16 kDa albumin, 13 kDa prolamin and type II glutelin.

Expression of rice seed storage-protein genes is dramatically regulated over a short period of seed maturation. To characterize the expression mechanism of the rice seed storage protein genes, their expression of major storage protein genes (16 kDa albumin, 13 kDa prolamin and type II glutelin) were compared by RNA blot analysis. Their coordinate expression suggests that the transcriptional regulatory machinery is shared among the glutelin, prolamin and albumin-genes. We isolated two novel genomic genes for prolamins (PG5a and PG5b) and obtained the promoter region of the glutelin gene by PCR. The 5'-flanking regions of these three rice seed storage protein genes were found to contain some similar conserved sequences. Nuclear extract partially purified from maturing rice seeds was used for the gel shift assay of the 5' region of the RA gene. We identified two DNA sequences of RA gene which were recognized by independent DNA-binding proteins. The complexes of these DNA sequences and DNA-binding proteins were inhibited by the fragments containing the 5' regions of the prolamin and glutelin genes, suggesting that these three genes share transcription factors.

Albumins↗
PubMed1996

Criteria for diagnosing distal radioulnar joint subluxation by computed tomography.

Bilateral wrist computed tomography (CT) was performed in 30 patients with suspected unilateral distal radioulnar joint (DRUJ) subluxation to evaluate dynamic DRUJ CT scanning with a straight elbow. Five CT criteria for diagnosing dorsovolar subluxation were examined. Maximum active supination and pronation on a conventional scanning table yielded satisfactory rotation (mean +/- SD, 119 degrees +/- 29 degrees) at the DRUJ, thus permitting a dynamic diagnosis of DRUJ subluxation. The radioulnar line method and the congruity method frequently yielded false positive results compared with bilateral diagnosis and were unreliable. Modifications of these two methods achieved sensitivity and specificity comparable to the epicenter method. We recommended the modified radioulnar line method for diagnosing dorsovolar subluxation using unilateral CT because of its excellent sensitivity and specificity combined with ease of technique.

Adolescent↗
PubMed1996

Triquetrohamate impaction syndrome: a case report.

A patient who had suffered from ulnar wrist pain for 3 years was diagnosed arthroscopically as having triquetrohamate impaction syndrome. Improvement of symptoms was obtained by arthroscopic treatment. This syndrome and the use of midcarpal arthroscopy are discussed.

Adult↗
PubMed1996

Effects of protease inhibitors on the absorption of phenol red and fluorescein isothiocyanate dextrans from the rat intestine.

The absorption enhancement effects of three types of protease inhibitors, aprotinin, bacitracin, and soybean trypsin inhibitor, on the small and large intestinal absorption of phenol red (PR) and fluorescein isothiocyanate dextrans (FDs) were examined in rats. Of these protease inhibitors, only bacitracin enhanced the absorption of PR and FDs from the rat small and large intestine. Thus, we suggest that bacitracin has not only a protease-inhibitory but also an absorption-enhancing capability. We examined the effects of various protease inhibitors on intestinal mucosal toxicity by measuring the leakage of Evans blue (EB) from the systemic circulation. Although there was a significant increase in the leakage of EB in the presence of bacitracin, it was considerably less than that in the case of polyoxyethylene 9-lauryl ether (BL-9), which was used as a positive control. Therefore, bacitracin may be a good model adjuvant for improving the intestinal absorption of poorly absorbable drugs because it did not cause serious intestinal mucosal damage, as seen in the case of BL-9.

Animals↗
PubMed1996

Immunochemical characteristics and localization on cells of protective antigen (PAg) prepared from Leptospira interrogans serovar lai.

Immuno-electron microscopic methods revealed that the protective antigen (PAg) of Leptospira interrogans serovar lai exists on the outer envelope sheathing the leptospiral cell body. PAg lost its protective activity after treatment by hydrolysis with 2 M formic acid at 100 C for 2 hr, or oxidation with periodate at 4 C for 40 hr. The antigenic oligosaccharide fraction was further purified from the hydrolyzed PAg by immunoaffinity column coupled with protective monoclonal antibody, LW2, and by gel filtration of HPLC. The antigenic oligosaccharide fraction contained two unknown sugars and 4-O-methylmannose (molar ratio 3:5:1). These findings suggested that these sugars are components of an antigenic determinant contributing to the protective immunity against serovar lai infection.

Antigens, Bacterial↗
PubMed1996

Biological and antigenic characterization of three BApNA-hydrolyzing proteases from the culture supernatant of Porphyromonas gingivalis.

Biological and antigenic distinction of 3-N-alpha-benzoyl-DL-arginine p-nitroanilide (BApNA)-hydrolyzing proteases (Pase-B, Pase-C and Pase-S) isolated from the culture supernatant of Porphyromonas gingivalis were determined. Immunoblotting analysis of these enzymes using a polyclonal antibody against Pase-S, which is a soluble, clostripain-like protease, revealed immunological distinction from Pase-C, a vesicle-associated thiol-protease. Pase-B, a vesicle-associated clostripain-like protease, reacted with the antibody and was also found to contain a considerable amount of carbohydrates in its structure, as compared with the others. Analysis of N-terminal amino acids of Pase-B provided a sequence not found in the SwissProt data bank or previously reported as N-terminal sequences of proteases from P. gingivalis. Pase-S, resembling Pase-B in its hydrolytic specificity, cleaved only arginine residues of peptides and degraded type IV and denatured type I collagen. Pase-C hydrolyzed N-alpha-benzoyl-DL-lysine p-nitroanilide and showed the strongest capacity of degrading native type I collagen. This enzyme was also the only one to possess hemagglutinating activity. Our findings suggest that Pase-S from P. gingivalis is less active than Pase-C and that the enzyme may be an isozyme of Pase-B.

Affinity Labels↗
PubMed1996

Ulnar impaction syndrome: MR imaging findings.

PURPOSE: To evaluate magnetic resonance (MR) imaging findings in ulnar impaction syndrome and changes after ulnar recession arthroplasty. MATERIALS AND METHODS: MR imaging and arthroscopy were performed in 30 wrists in 27 patients (aged 15-62 years) in whom ulnar impaction syndrome was diagnosed on the basis of physical examinations. MR imaging was performed in 11 wrists before and after surgery. T1- and T2-weighted spin-echo images were obtained. Signal intensities in the lunate, triquetrum, and ulnar head were evaluated. RESULTS: There was focal abnormal signal intensity of the ulnar aspect of the lunate in 87% of wrists, of the radial aspects of the triquetrum in 43%, and of the radial aspects of the ulnar head in 10% before surgery. The signal intensity of the abnormalities was decreased on T1-weighted and decreased or increased on T2-weighted images. After surgery, the signal intensity of the lunate shifted from low through slightly low to normal on T1-weighted and from low through high to normal on T2-weighted images. CONCLUSION: Most ulnar impaction syndrome cases have characteristic focal signal intensity changes in the ulnar part of the lunate. The signal intensity often returns to normal after ulnar recession arthroplasty.

Adolescent↗
PubMed1996

Restricted propagation of cytoplasmic Ca2+ oscillation into the nucleus in guinea pig cardiac myocytes as revealed by rapid scanning confocal microscopy and indo-1.

Two-dimensional images of cytoplasmic and nuclear free Ca2+ movements in cardiac myocytes were obtained at 67-msec intervals using a Ca(2+)-sensitive fluorescence probe, indo-1, and a rapid scanning confocal laser microscope, Nikon RCM8000. Isolated guinea pig ventricular cells were loaded with indo-1 and stimulated at 0.5 Hz through patch pipettes. On stimulation, nuclear Ca2+ concentration ([Ca2+]) was observed to rise and fall following cytoplasmic [Ca2+] with an obvious delay. Application of isoproterenol significantly increased the peak [Ca2+] on stimulation in both the cytoplasm and nucleus with no substantial change in the basal [Ca2+]; the increase in peak [Ca2+] produced by application of isoproterenol was larger in the cytoplasm than in the nucleus. Under a low [Na+] condition, the basal [Ca2+] was increased from the control values in both the cytoplasm and nucleus; no difference in basal [Ca2+] was observed between the two regions. The increase in peak [Ca2+] by low [Na+] in the cytoplasm was significantly larger than that in the nucleus. When the cells were voltage clamped at 0 mV for 3 sec, no difference in the steady state [Ca2+] was observed between the cytoplasm and nucleus. Nuclear [Ca2+] was also observed to increase following a Ca2+ wave, a local increase in [Ca2+] propagating within the cytoplasm, with a delay. Thus, we demonstrated in isolated myocardial cells that cytoplasmic Ca2+ movements, although hampered by the nuclear envelope, are propagated into the nucleus, a mechanism through which factors affecting cytoplasmic Ca2+ may influence intranuclear events.

Animals↗
PubMed1996

Immunochemical and biochemical identification of the rice seed protein encoded by cDNA clone A3-12.

Previously isolated cDNA clone A3-12 that was expressed in E. coli as the fusion protein with Trp E showed immunoreactivity with the mouse antibody raised against isolated alpha-globulin from rice seed. The N-terminal amino acid sequences determined for the purified alpha-globulin and its tryptic peptides were identical with the deduced amino acid sequence reported, except for two residues at the protein N terminus. An error in the reported sequence was confirmed by re-sequencing the cDNA, the nucleotide sequence for the two N-terminal residues being shown to be CAGCTG and not CACGTG. Thus, the protein encoded by cDNA clone A3-12 was identified to be the major rice seed globulin, alpha-globulin, with an apparent molecular mass of 26kDa.

Alpha-Globulins↗