Search PubMed⌕ Search

Biomedical subjects

R Nakamura

Publications and source records attributed to R Nakamura.

At least 109 records · Page 6Linked to original sources
PubMed1998

Proximal row carpectomy versus limited wrist arthrodesis for advanced Kienböck's disease.

The outcomes in 20 patients with advanced Kienböck's disease treated by proximal row carpectomy (seven patients) or limited wrist arthrodesis (13 patients) were reviewed retrospectively. Postoperatively, the results were more satisfactory in terms of wrist pain, the range of wrist flexion-extension, and grip strength following limited wrist arthrodesis than after proximal row carpectomy, although the differences were not statistically significant. We recommend scaphotrapeziotrapezoid arthrodesis in selected patients with advanced Kienböck's disease who have a fragmented lunate.

Adolescent↗
PubMed1998

Progressive patterns of degenerative arthritis in scaphoid nonunion demonstrated by three-dimensional computed tomography.

Degenerative arthritis following scaphoid nonunion was studied in 28 patients (29 wrists) using X-ray computed tomography and three-dimensional computed tomography (3-DCT). Degenerative changes were observed in 18 wrists with plain radiography and 27 wrists with 3-DCT. 3-DCT imaging more readily revealed osteophyte formation in osteoarthritis than plain radiography. 3-DCT images showed degenerative changes in the distal fragment of the scaphoid earlier than plain radiography. We found three stages of osteophyte formation in the radioscaphoid joint using 3-DCT. In the first stage, a linear osteophyte formed along the most radial portion of the distal fragment of the scaphoid. In the second stage, the radial styloid became pointed. In the third stage, the osteophyte on the distal fragment enlarged and lay over the dorsum of the radioscaphoid joint and other intercarpal joints.

Adolescent↗
PubMed1998

Ulnar styloid malunion with dislocation of the distal radioulnar joint.

Four patients with dorsal dislocation of the distal radioulnar joint and ulnar styloid malunion had corrective osteotomy of the ulnar styloid. Dislocation of the distal radioulnar joint was reduced in three of four patients. Subluxation persisted in the remaining patient. Wrist function improved in all patients. These results support the contention that a displaced ulnar styloid fracture with distal radioulnar joint dislocation should be reduced and internally fixed. Corrective osteotomy is recommended for malunion of the ulnar styloid associated with dislocation of the distal radioulnar joint.

Adolescent↗
PubMed1998

Arthroscopic evaluation of radial osteotomy for Kienböck's disease.

To determine whether osteoarthritic changes of the perilunate articular cartilage improve following radial osteotomy for Kienböck's disease and correlate with clinical results, arthroscopic examination was performed in 18 patients concurrently with radial osteotomy and at the time of removal of implants after an average of 21 months. Clinical results were satisfactory. All patients improved the preoperative level of pain. Wrist function was improved in range of motion and grip strength. Radiographic findings also demonstrated prevention of further collapse of the lunate. However, follow-up arthroscopic examination revealed progression of osteoarthritis in the area of the lunate in two thirds of the cases. There was no correlation between arthroscopic observations and clinical results. A long-term follow-up period is therefore advocated for evaluation of radial osteotomy because of the possibility of additional progression of osteoarthritic changes.

Adolescent↗
PubMed1998

Paravertebral ligamentous ossification: DISH, OPLL and OLF.

This is an overview of paravertebral ligamentous ossification based on our 5-year experience in ossification of posterior longitudinal ligament (109 cases) and ossification of ligamentum flavum (18 cases). Paravertebral ligamentous ossification is designated as the disorder caused by frequently coexisting ossification of paravertebral ligaments, DISH, OPLL, and OLF. The frequency of the occurrence of isolated ossification of PLL and OLF in Japan is still uncertain. DISH, which is not rare in Europe or North America, is frequently associated with ossification of the posterior aspect of the vertebral bodies, but it may be less symptomatic. The major cause of the probably higher incidence of symptomatic patients in Japan may be due to associated narrowing of the spinal canal.

Female↗
PubMed1998

Effects of astemizole on ventricular activation, effective refractory periods, RT intervals, and programmed stimulation-induced ventricular arrhythmias in dog hearts with myocardial infarction.

To clarify the mechanisms of enhanced cardiotoxic effects of astemizole in ischemic hearts, we examined the effects of astemizole on ventricular activation, effective refractory periods (ERPs), RT intervals, and incidence of programmed electrical stimulation (PES)-induced ventricular arrhythmias in the dog heart after myocardial infarction. Myocardial infarction was produced by the two-stage ligation of left anterior descending coronary artery in dogs. At 7 days after ligation, bipolar electrodes were sutured on the ventricular surface of the infarcted and the normal zones for applying an electrical stimulation or recording the ventricular activation. Ventricular-activation delay was measured in a premature excitation, which was produced by a stimulation at a coupling interval between 300 and 140 ms on the ventricular surface of the normal zone. The ERP and the RT interval were determined during atrial pacing. The ventricular-activation delay increased after astemizole at doses of 0.3-3 mg/kg in the infarcted zone and at 3 mg/kg in the normal zone. Astemizole at doses of 0.3-3 mg/kg significantly prolonged the ERP to a greater extent in the infarcted zone than in the normal zone, and thus a dispersion of ERP between normal and infarcted zones increased. The RT interval in the normal zone significantly increased after astemizole to a greater extent at a long coupling interval. The RT interval in the infarcted zone also increased after astemizole at doses of 0.1-3 mg/kg to a greater extent than that in the normal zone. Astemizole at doses of 0.3-3 mg/kg increased the incidence of PES-induced ventricular arrhythmias. In conclusion, enhanced cardiotoxic effects of astemizole in ischemic hearts may be caused by increased activation delay in the ischemic regions and increased ERP dispersion in the ventricle.

Animals↗
PubMed1998

Cross-reactivity of specific antibodies directed to heat shock proteins from periodontopathogenic bacteria and of human origin [corrected].

This study describes the immunological characterization of two different classes of heat shock proteins isolated from periodontopathogenic bacteria. Analysis of the N-terminal amino acid sequence of a 74-kDa protein from Bacteroides forsythus showed a high degree of homology with the DnaK protein from Escherichia coli. However, this heat shock protein from B. forsythus reacted very weakly with a commercial anti-DnaK polyclonal antibody by dot-blotting. GroEL-like proteins isolated from Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and B. forsythus showed a high degree of homology of their N-terminal amino acid sequences. In general, polyclonal antibodies raised against each GroEL-like protein showed a high level of cross-reactivity. The cross-reactivity of antibodies to bacterial DnaK-like proteins was much more limited. Our findings suggest that DnaK- and GroEL-like proteins from periodontal pathogens are well conserved and that the GroEL-like proteins resemble each other more closely.

Amino Acid Sequence↗
PubMed1998

Sleep improvement by light in a demented aged individual.

We administered daily morning bright light exposure in two separate periods to a demented aged subject in a nursing home and analyzed the sleep pattern changes from the sleep diary over 6 months. In the first light exposure period, the ratio of sleep time in night hours increased and maintained a higher value throughout the period than the previous baseline. After stopping the light exposure, the sleep pattern of the subject deteriorated. Resuming the light exposure reproduced similar sleep pattern changes. These results suggest that morning bright light exposure provides a better environment for aged persons to maintain a regular sleep-wake pattern.

Aged↗
PubMed1998

Subcellular localization and cytotoxic activity of the GroEL-like protein isolated from Actinobacillus actinomycetemcomitans.

The subcellular locations, ultrastructure, and cytotoxic activity of the GroEL-like protein from Actinobacillus actinomycetemcomitans were investigated. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) clearly indicated that synthesis of the GroEL-like protein is substantially increased after a thermal shock. Analysis of the purified native GroEL-like protein by transmission electron microscopy revealed the typical 14-mer cylindrical molecule, which had a diameter of about 12 nm. A. actinomycetemcomitans cells grown at 35 degreesC and heat shocked at 43 degreesC were fractionated, and fractions were separated by SDS-PAGE and analyzed by Western immunoblotting using antibodies to GroEL- and DnaK-like proteins. The GroEL-like protein was found in both the soluble and membrane fractions, whereas the DnaK-like protein was mostly found in the cytoplasm. An increase in specific proteins, including the GroEL- and DnaK-like proteins, was found in heat-shocked cells. The subcellular localization of the GroEL-like protein was examined by immunoelectron microscopy of whole cells. More GroEL-like protein was detected in stressed cells than in unstressed cells, and most of it was found not directly associated with outer membranes but rather in extracellular material. The native GroEL-like protein was assessed for cytotoxic activities. The GroEL-like protein increased the proliferation of periodontal ligament epithelial cells at concentrations between 0.4 and 1.0 microgram/ml. The number of cells in the culture decreased significantly at higher concentrations. A cell viability assay using HaCaT epithelial cells indicated that the GroEL-like protein was strongly toxic for the cells. These studies suggest the extracellular nature of the GroEL-like protein and its putative role in disease initiation.

Aggregatibacter actinomycetemcomitans↗
PubMed1998

Epicondylitis among cooks in nursery schools.

OBJECTIVES: To investigate the prevalence and risk factors of epicondylitis among cooks in nursery schools in a cross sectional study because they are suspected to have strenuous workloads on the hands and arms. METHODS: Prevalence of epicondylitis among 209 nursery school cooks and 366 control workers aged 40-59 were studied. Both groups consisted of women workers chosen from 1299 subjects who agreed to participate from 1329 social welfare employees in a city. All workers were interviewed with a questionnaire and had a clinical examination of the tenderness to palpation of epicondyles and epicondylar pain provoked by resisted extension and flexion of the wrist. RESULTS: Nursery school cooks had a significantly higher prevalence of epicondylitis (11.5%) than the controls (2.5%). In a logistic regression model, job title of the cook was also found to have a strong association with epicondylitis (odds ratio (OR) 5.4, 95% confidence interval (95% CI) 2.4 to 11.9) after adjustment for age, body length, and body mass index. Weaker associations were also found between epicondylitis and suspected job stress or workload scores for mechanical workload and psychosocial stressors based on factor analysis. CONCLUSIONS: This study supported the hypothesis that nursery school cooks had a higher prevalence of epicondylitis than other workers with less strenuous hand and arm tasks. It was suggested that risk factors of epicondylitis would be multifactorial, including mechanical workload and psychosocial factors.

Adult↗
PubMed1998

Massive intraperitoneal hemorrhage and hypovolemic shock due to rupture of a coronary vessel of a uterine leiomyoma: a report of two cases.

Intraperitoneal hemorrhage due to uterine leiomyoma is extremely rare. Recently, we encountered such two cases and herein describe them. Case 1 involved a 34-year-old, nulliparous woman referred to our hospital because of a sudden onset of shock while she was playing a softball game. She had a large abdominal tumor and a hemoperitoneum, and was diagnosed as having a ruptured ovarian tumor. Exploratory laparotomy showed a rupture of the coronary vein of a large uterine leiomyoma. The patient was treated with myomectomy and did well postoperatively. Case 2 involved a 44-year-old, multiparous woman referred to our hospital because of sudden onset of lower abdominal pain while defecating. She had a uterine leiomyoma and a hemoperitoneum, and was diagnosed as having a ruptured splenic artery. Exploratory laparotomy showed rupture of the coronary artery of a uterine leiomyoma. The patient was treated with total abdominal hysterectomy and did well postoperatively. These cases suggest that intraperitoneal hemorrhage associated with uterine leiomyoma, although rare, should be considered in women with hypovolemic shock and a large pelvic mass.

Adult↗
PubMed1997

AMPA receptor-mediated slow neuronal death in the rat spinal cord induced by long-term blockade of glutamate transporters with THA.

Excitotoxicity secondary to the loss of glutamate transporters (GluT) has been proposed as a possible pathogenetic mechanism for neuronal degeneration in amyotrophic lateral sclerosis. We therefore investigated whether prolonged in vivo pharmacologic inhibition of GluT would result in neuronal damage in the rat. DL-Threo-beta-hydroxyaspartate (THA), a potent GluT inhibitor, and glutamate were continuously infused into the rat spinal subarachnoid space by using a mini-osmotic pump. Animals that received both THA and glutamate, but not those received either singly, displayed tail paralysis with or without hind-limb paralysis and urinary incontinence after the third postoperative day. Pathologically, symptomatic animals exhibited neuronal loss with a variable extent of gliosis preferentially involving the dorsal horn of the lumbosacral cord. In the rostral spinal segments adjacent to those regions of intense pathologic changes, small neurons in the dorsal horn were selectively destroyed, a pattern similar to the late-onset neuronal damage induced by continuous intrathecal administration of 1-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) [R. Nakamura et al., Brain Res. 654 (1994) 279-285]. These behavioral and pathologic changes were blocked by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), suggesting that pharmacologic blockade of GluT causes selective neuronal damage in vivo by AMPA receptor activation.

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

Two-dimensional millisecond analysis of intracellular Ca2+ sparks in cardiac myocytes by rapid scanning confocal microscopy: increase in amplitude by isoproterenol.

Two dimensional images of myocardial Ca2+ sparks, non-propagating local rises in cytoplasmic Ca2+ concentration, were obtained at 4 msec intervals with a rapid-scanning confocal laser microscope, Nikon RCM 8000, and fluo-3. Spontaneous Ca2+ sparks were observed at apparently random sites throughout the cytoplasm of rat ventricular cells. The duration of sparks was 30 to 40 msec and the time to peak intensity about 10 msec. Ryanodine (1 microM) completely inhibited Ca2+ sparks while nicardipine (3 microM) had no effect. Isoproterenol (1 microM) had no effect on the frequency and distribution of Ca2+ sparks but significantly increased their amplitude. These results suggest that myocardial Ca2+ sparks are the result of spontaneous release of Ca2+ from the sarcoplasmic reticulum and that beta-adrenergic stimulation may result in functional modification of the ryanodine receptor channel.

Adrenergic beta-Antagonists↗
PubMed1997

Stage specific expression of milk fat globule membrane glycoproteins in mouse mammary gland: comparison of MFG-E8, butyrophilin, and CD36 with a major milk protein, beta-casein.

The expression of mouse milk fat globule membrane (MFGM) glycoproteins, MFG-E8, butyrophilin, CD36 was analyzed by Northern blot analyses. MFG-E8 and butyrophilin mRNAs were specifically detected in the mammary gland of lactating mice, whereas CD36 mRNA was detected in the heart and lung as well as in the mammary gland of lactating mice. The mRNAs of the three MFGM glycoproteins accumulated at mid-lactation were about 2-10-times as much as those of the early and late gestation stages, whereas beta-casein mRNA accumulation was dramatically increased; the mRNA at mid-lactation was no less than 40-times as much as that before lactation. In mouse mammary epithelial cell lines, HC11 and COMMA-1D, only a slight or almost no enhancement for the expression of MFG-E8, butyrophilin and CD36 mRNAs was induced simply by the treatment with the lactogenic hormones such as prolactin, insulin and dexamethasone, whereas the beta-casein mRNA expression was remarkably enhanced only by that treatment. Furthermore, while the beta-casein protein was constantly detected in milk throughout the lactation stage, the content of MFG-E8 and butyrophilin proteins increased during the lactation with an increase in the milk fat content. These results suggest that the stage-specific expression of milk fat globule membrane glycoproteins in mammary epithelial cells is regulated in a similar but not necessarily identical mechanism to that of a major milk protein, beta-casein.

Animals↗
PubMed1997

Avulsion fracture of the metacarpophalangeal joint of the finger.

Six patients with avulsion fractures of the metacarpophalangeal joints of the fingers are reported. Operation was performed in all cases. Judging from the operative findings, the radiological assessment of fragment shape is helpful in treatment. Surgery is recommended when the fragment is triangular or rectangular in shape because the fracture involves the articular surface. Conservative treatment is effective if the fragment is round because the articular surface of the joint is not involved in this type of fracture. The avulsed fragment often overlaps the metacarpal head and a collateral ligament injury is likely to be misdiagnosed. It is important to suspect this injury and assess the shape of the whole fragment for a good functional result.

Adolescent↗
PubMed1997

The ulnocarpal stress test in the diagnosis of ulnar-sided wrist pain.

Forty-five patients with persistent ulnar-sided wrist pain and a positive ulnocarpal stress test were investigated by X-ray, arthrography, 99mTechnetium bone scanning, magnetic resonance imaging and wrist arthroscopy. Ulnar wrist pathology was positively identified in nine of 45 patients by X-ray, 18 of 37 by arthrography, 19 of 27 by bone scan, four of 33 by MRI, and in all 45 patients by arthroscopy. The final diagnosis was ulnocarpal abutment syndrome in 28 patients, traumatic triangular fibrocartilage (TFC) tear in six, lunotriquetral (LT) ligament tear in five, TFC and LT ligament tear in one, wrist arthritis in four and cartilaginous free body in one. The ulnocarpal stress test is a useful provocative test, and a positive test suggests the presence of ulnar-sided wrist pathology. The test is sufficiently sensitive to warrant further investigation by arthroscopy.

Adolescent↗
PubMed1997

Duplicated thumb bifurcation at the metacarpophalangeal joint level: factors affecting surgical outcome.

In order that the factors causing poor surgical outcome might be clarified, 175 duplicated thumbs bifurcating at the metacarpophalangeal joint level were analyzed. Cases were further divided into types A-D, based upon the details of the bifurcation form; that is, based on the connection of the radial digit to the ulnar components by either cartilage, joint, or fibrous tissue. The incidence of each type was 16% for type A (wide cartilaginous connection between phalanges), 68% for type B (2 separate phalanges), 6% for type C (cartilaginous connection to metacarpal), and 10% for type D (fibrous connection to joint capsule). Triphalangeal types and the relative size of the excised digit were determined by the preoperative radiograph. One hundred six cases were available for evaluation with a minimum of 3 years' follow-up. Good results were obtained in 50% of types A and C and in 80% of types B and D. Three phalanges in the preserve digits were observed in 10 cases and surgery on all but 1 resulted in a fair outcome. In cases where the size of the excised digit was more than 75% of the preserved digit, the results were fair or pool in 93%. The presence of subdivisions of types A and C, of 3 phalanges in the preserved digit, and of a relatively bigger excised digit were factors causing poor results, despite intensive reconstructive surgery.

Child, Preschool↗