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Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 19 recordsLinked to original sources
PubMed1992

Differential effect of subspecies of lipoprotein containing apolipoprotein A-I on cholesterol efflux from cholesterol-loaded macrophages: functional correlation with lecithin: cholesterol acyltransferase.

Two species of lipoprotein containing apoA-I, one containing only apoA-I (LpA-I), and the other containing apoA-I and apoA-II (LpA-I/A-II), were tested for their effects on macrophage foam cells. Rat macrophages were converted to foam cells by incubation with radiolabeled acetylated LDL. Incubation with LpA-I or LpA-I/A-II decreased the cellular cholesteryl esters (CE) mass. However, the free cholesterol (FC) mass was only reduced by LpA-I. All the radioactivity excreted into the medium was associated with LpA-I or LpA-I/A-II; 39% of the excreted radioactivity was esterified in LpA-I and 10% in LpA-I/A-II. Upon complete inactivation of lecithin: cholesterol acyltransferase (LCAT) activity with dithiobisnitrobenzoic acid, the cholesterol reducing capacity of LpA-I was weakened significantly. However, the CE mass reducing capacity of LpA-I/A-II was not affected. When LpA-I and LpA-I/A-II were combined, the cholesterol reducing capacity of the mixture was similar to that of LpA-I alone. However, LpA-I re-isolated from the medium showed a lower esterification rate than did the re-isolated LpA-I/A-II, thereby indicating that the cholesterol esterified in LpA-I was transferred to LpA-I/A-II. These results suggest that (i) the function of LpA-I is closely linked to the LCAT activity while that of LpA-I/A-II is not, and (ii) LpA-I in concert with LpA-I/A-II induces a series of extracellular events; LCAT-mediated esterification of excreted FC by LpA-I and a subsequent CE transfer to LpA-I/A-II. These mechanisms might be important for net cholesterol efflux from macrophage foam cells in physiological states.

Adolescent↗
PubMed1992

Nucleotide sequence of a cDNA clone encoding a major allergenic protein in rice seeds. Homology of the deduced amino acid sequence with members of alpha-amylase/trypsin inhibitor family.

A cDNA clone of rice major allergenic protein (RAP) was isolated from a cDNA library of maturing rice seeds. The cDNA had an open reading frame (486 nucleotides) which coded a 162 amino acid residue polypeptide comprising a 27-residue signal peptide and a 135-residue mature protein of M(r) 14,764. The deduced amino acid sequence of RAP showed a considerable similarity to barley trypsin inhibitor [1983, J. Biol. Chem. 258, 7998-8003] and wheat alpha-amylase inhibitor [1981, Phytochemistry 20, 1781-1784].

Allergens↗
PubMed1992

Changes in plasma and duodenal cholecystokinin concentrations after pancreatic duct occlusion in rats.

The changes in plasma and duodenal cholecystokinin (CCK) concentrations after pancreatic duct occlusion were examined in rats. The rats were sacrificed 1, 3, 7, 10, 14, and 30 days after occlusion of the duct. Histological examination showed acute inflammation on days 1 and 3 after duct occlusion, interstitial fibrosis and regenerative changes on days 7, 10, and 14, and pancreatic atrophy on day 30. The plasma CCK concentration increased from 0.45 pM to 2.0 pM after the occlusion and then remained high throughout the observation period. In contrast to the stable increase in plasma CCK concentration, the CCK content in the duodenum increased on days 1 and 3, decreased on day 7, increased on day 10, reaching over the control level on day 14, and then returned to the control level on day 30. Administration of boiled and 10-fold concentrated rat pancreatic juice or human pancreatic secretory trypsin inhibitor for seven days after pancreatic duct occlusion reversed the decrease in duodenal CCK content. The major molecular forms of duodenal CCK were CCK-8, -33, and -58. These results indicate that (1) basal plasma CCK concentration did not reflect the duodenal CCK content, (2) duodenal CCK content was well correlated with a decrease in inflammation in the pancreas, and (3) a nonenzymatic component in the pancreatic juice reversed the decrease in duodenal CCK content and body weight caused by pancreatic duct occlusion.

Acute Disease↗
PubMed1992

Generation of plasma kinin by three types of protease isolated from Porphyromonas gingivalis 381.

Three types of protease (A, B and C) isolated from the culture supernatant of Porphyromonas gingivalis 381 had peculiar activities on kinin generation from high molecular-weight kininogen in vitro. Protease C released bradykinin from the kininogen in a reaction mixture containing 2 mM dithiothreitol, but A and B did not. However, the activity of degrading bradykinin was much stronger in protease A and B than in C. These findings suggest that only protease C shows plasma kallikrein activity.

Bradykinin↗
PubMed1992

Magnetic resonance imaging in Kienböck's disease.

With a 1.5 tesla superconducting M.R. imager and surface coil, M.R. imaging achieved high resolution analysis of the wrist on five normal wrists and 26 wrists with Kienböck's disease. The purpose of this study was to establish new criteria for diagnosis, staging and prognosis of Kienböck's disease, based on signal characteristics on T1- and T2-weighted images. Focal loss of signal intensity of the lunate on T1-weighted image was an indication of Kienböck's disease. A decreased signal containing a high spot and increased signal intensity of the lunate on T2-weighted images indicated a better prognosis. After osteotomy of the radius, the signal intensity of the lunate returned to normal and Lichtman's stage II cases had better results than those in stage III. M.R. imaging is ideal for evaluating the lunate in Kienböck's disease.

Adult↗
PubMed1992

Magnetic resonance imaging in scaphoid fractures.

The use of a 1.5 tesla superconducting M.R. imager and surface coil was found to enhance the ability of M.R.I. to depict the fine anatomy of the wrist. Five healthy volunteers and 28 patients with scaphoid fractures underwent M.R.I., which made possible a definitive diagnosis of scaphoid fractures at an early stage. A fresh fracture was identified by decreased or iso signal intensity on the T1-weighted image and increased signal intensity on the T2-weighted image. This increase continued until bony union was apparent on radiographs. On the T2-weighted image, high signal intensity was characteristic of fresh fractures and suggested that bony union was possible. When bony union was complete, the intensity of the signal for the scaphoid on both T1- and T2-weighted images returned to normal. M.R.I. should thus prove useful in the diagnosis of scaphoid fractures.

Adolescent↗
PubMed1992

The Sauvé-Kapandji procedure for chronic dislocation of the distal radio-ulnar joint with destruction of the articular surface.

The Sauvé-Kapandji procedure has been performed in 15 non-rheumatoid patients with chronic distal radio-ulnar joint dislocation accompanied by joint damage or deformity. The clinical results were favourable; wrist pain improved in all patients, wrist flexion-extension was increased by more than 10 degrees in nine patients, grip strength of at least 80% of the contralateral wrist was achieved in 11 patients, and forearm rotation was more than 150 degrees in 12 patients. However, X-ray examination revealed an unstable proximal ulnar stump and radio-ulnar convergence in all patients similar to that associated with the Darrach procedure. Although the Sauvé-Kapandji procedure can preserve ulnar support of the wrist and is believed to yield more satisfactory results than the Darrach procedure, its extensive use is not recommended for non-rheumatoid distal radio-ulnar joint disorders, but it is recommended for chronic distal radio-ulnar joint dislocation with articular injury or deformity.

Adult↗
PubMed1992

Cleft hand, syndactyly and hypoplastic thumb.

The clinical features of 58 patients with typical cleft hand were examined and compared with 86 patients with syndactyly between the long and ring fingers, 27 patients with syndactyly between the ring, little and other fingers, 53 patients with hypoplastic thumb and 100 patients with symbrachydactyly. The clinical findings of the typical cleft hand resembled those of syndactyly. There were two unusual cases of typical cleft hand associated with hypoplastic thumb, congenital heart anomalies and absence of the axial triradius. One of these also had cleft lip and palate. The critical embryonic period of the heart anomaly is early, while that of the cleft lip and palate is late. These findings suggest that an embryo with typical cleft hand and hypoplastic thumb results from impairments at two different times in the early embryonic period.

Abnormalities, Multiple↗
PubMed1992

Long-standing extended dynamic splintage and release of an abnormal restraining structure in camptodactyly.

62 patients with camptodactyly of the little finger have been reviewed, and only five cases failed to respond to conservative treatment. These cases are reported. One patient could straighten the deformed PIP joint with snapping, and the other two were resistant to conservative treatment and were found to have a restraining structure requiring release. These findings are in keeping with an imbalance between flexion and extension forces due to long-standing malposition of the extensor lateral bands. Operative treatment should be reversed for cases of failed conservative treatment, which should be started as early as possible.

Adult↗
PubMed1992

Lipoprotein-containing apolipoprotein A-I: sex-related quantitative and qualitative changes in this lipoprotein subspecies after ingestion of fat.

We investigated the postprandial changes of two species of lipoproteins containing apolipoprotein (apo)A-I: lipoprotein containing apo A-I but no apo A-II (LpA-I), and lipoprotein containing apo A-I and apo A-II (LpA-I/A-II). These lipoproteins were isolated from 10 men and 11 women at 0, 4, and 6 h after they had eaten butter. In LpA-I, the concentrations of all lipids except triglyceride were increased at 4 and 6 h in the women. In the men all lipids were increased only at 4 h. The increase of apo A-I concentration was found at 6 h only in the women. In LpA-I/A-II, the concentrations of all lipids were increased at 4 h and only phospholipid (PL) was increased at 6 h in the women. In the men, free cholesterol and PL were increased at 4 and 6 h. The increases of apo A-I and apo A-II concentrations were found at 4 and 6 h only in the men. These results suggest that the postprandial changes are sex-related and may relate to the different incidence of atherosclerotic cardiovascular disorders.

Adult↗
PubMed1992

Carbohydrate binding specificity of monoclonal antibodies raised against lactose-protein Maillard adducts.

Three hybridoma antibodies (L101, L104, and L117) specific for lactose-protein amino carbonyl products (Maillard adducts) were obtained by immunizing mice with the lactose-ovalbumin Maillard adduct and by screening with the lactose-bovine serum albumin (BSA) adduct. They reacted with the Maillard adducts of lactose with several different proteins, but not with the adducts of several other reducing sugars. L101 reacted well with the lactose-BSA adducts formed by 2- to 16-day incubation, whereas L104 and L117 reacted with the advanced stage reaction products but not with the adducts of 2-day incubation. The competitive inhibition of the antibody binding by several mono- and disaccharides showed that lactulose (4-O-beta-D-galactopylanosyl-D-fructose) was the best inhibitor for all three antibodies, and that L104 and L117 were inhibited by methyl-beta-D-galactoside more effectively than L101. These results suggested that different components produced during the progress of the Maillard reaction could be antigenic determinants, and that the carbohydrate moiety including the terminal galactosyl residue played an important role in the antibody binding to the lactose-protein Maillard adducts.

Animals↗
PubMed1992

Survey of a receptor protein in human erythrocytes for hemagglutinin of Porphyromonas gingivalis.

The purpose of this study is to survey a receptor protein in human erythrocyte membrane for the hemagglutinin (HA) of Porphyromonas gingivalis. Human erythrocytes were modified by either chymotrypsin or P. gingivalis HA along with the disappearance of their hemagglutinating ability and the removal of the band 3 protein. By preparative electrophoresis, this protein was isolated and purified from human erythrocytes. The purified protein showed strong inhibitory activity for hemagglutination and the binding to P. gingivalis cells, whose binding sites were calculated to be approximately 9000, suggesting its binding to the active site of HA. Hemagglutinin purified from P. gingivalis by affinity absorption to sheep erythrocyte ghosts possessed strong trypsin-like activity, and both the HA and the enzyme activities were inhibited by arginine. Specific modification of arginyl residues in human erythrocytes by phenylglyoxal diminished the hemagglutinating ability. From the similarity of the inhibition profile and possible active sites between HA and the trypsin-like protease, it is suggested that hemagglutination may occur as a result of the primary reaction of the enzyme (protease) and the substrate. These results suggest that band 3 may be a key protein in human erythrocyte membrane for HA from P. gingivalis and its binding sites may be arginyl residues of the protein.

Aminopeptidases↗
PubMed1992

Computer-assisted gait training (CAGT) of hemiparetic stroke patients: whose recovery is most predictable?

Maximum walking speed for 10 m distance of 109 hemiparetic stroke patients was examined every week for 7 weeks after starting computer-assisted gait training (CAGT), and the relation between the time since stroke onset (x) and the maximum walking speed (y) was approximated by a hyperbolic function, y = A-B/x. The patients were divided into two groups, 91 cases with a significant fit of the function (fit group) and 18 without fit (non-fit). The gain of maximum walking speed during 7 weeks was larger in the fit group, compared to the non-fit. Computed tomography examination revealed that the significant fit was mostly expected in patients with the caspular lesion without the cortical involvements except the frontal. The time at which the maximum walking speed of the patients belonging to the fit group would reach the midst of the estimated full recovery of gait can be predicted at the start of CAGT (R2 = 0.955), using two variables: the time since stroke onset and the maximum walking speed.

Brain↗
PubMed1992

Recovery of impaired motor function of the upper extremity after stroke.

Manual function score (MFS) of 174 hemiparetic stroke patients was examined every week for 8 weeks after starting the occupational therapy with programs based on MFS recovery profile, and the relation between the time since stroke onset (x) and MFS (y) was approximated by a hyperbolic function, y = A - B/x. The patients were classified into two groups, 125 cases (71.8%) with statistically significant fit of the function (fit group) and 49 without fit (non-fit). Using demographic and neurological variables of each patient, characteristics of the patients with regular recovery were analyzed. The results indicated that the gain of MFS during 8 weeks of the therapy was large in the fit group compared to the non-fit, and the regular recovery could be mostly expected in rather young patients, those with early start of the therapy, and those without ataxia, mental deterioration, and cortical lesions.

Arm↗
PubMed1992

Somatosensory conduction delay in central and peripheral nervous system of diabetic patients.

Fifty-four diabetic patients with or without clinical evidence of neuropathy and with no clinical evidence of CNS dysfunction were studied by somatosensory-evoked potentials after electrical stimulation of the median nerve at the wrist and recorded from the scalp electrode against a noncephalic reference. Peripheral conduction index, calculated as the distance from the wrist to the C7 spinous process divided by the P9 latency, was significantly decreased (P less than 0.01) in diabetic patients (69.81 +/- 6.47 m/s) compared with 28 age-matched nondiabetic subjects (76.85 +/- 5.65 m/s). The P11-P13 interpeak latency, representative of the transit time from the dorsal column at the level of the sensory input into the cervical cord to the brain stem along the somatosensory pathways (CCT1), and the P13-N19 interpeak latency, representative of the transit time from the brain stem to the somatosensory cortex (CCT2), were significantly increased in diabetic patients (CCT1, 2.51 +/- 0.63 ms; CCT2, 5.76 +/- 0.92 ms) compared with nondiabetic subjects (CCT1, 2.28 +/- 0.36 ms, P less than 0.05; CCT2, 5.18 +/- 0.51 ms, P less than 0.01). We conclude that, in diabetic patients, neurophysiological abnormalities may be present in two distinct parts of the CNS and the peripheral nervous system.

Blood Pressure↗
PubMed1992

[Multivariate analysis of the clinical signs in late cortical cerebellar atrophy (LCCA) in Japan--compared with olivo-ponto-cerebellar atrophy (OPCA) and hereditary cortical cerebellar atrophy (HCCA)].

We investigated the clinical features of 179 patients with late cortical cerebellar atrophy (LCCA) comparing with 382 patients with olivo-ponto-cerebellar atrophy (OPCA) and 91 patients with hereditary cortical cerebellar atrophy (HCCA) using multivariate analysis. They had no significant difference in durations from onset. Disorders of finger-nose test were of more severity and disorders of heel-knee test were less involved in LCCA than in HCCA. Eye movements tended to be normal in LCCA. LCCA showed more depressive and euphoric character than OPCA and HCCA. Analysis of LCCA and OPCA demonstrated that LCCA revealed hypotonia in muscles, normal or weak reactions of muscle stretch reflexes. There existed 21.4 percent of cases which could not be discriminated by multivariate analysis using clinical signs in LCCA and OPCA. Multivariate analysis of LCCA and HCCA, which are very similar in clinical signs, showed 66.3 percent of discriminatory rate. Thus, we could diagnose them to a certain extent only by clinical signs.

Aged↗