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Biomedical subjects

H Oka

Publications and source records attributed to H Oka.

At least 127 records · Page 7Linked to original sources
PubMed1998

Angiographic evaluation of culprit lesions in acute coronary syndrome: relation to the original site on previous coronary angiography.

Culprit lesions in acute coronary syndrome [acute myocardial infarction (AMI) and unstable angina pectoris (UAP)] were examined angiographically in 222 patients who had previously undergone coronary angiography (CAG). The observation period lasted 5 years after primary CAG in medically treated patients (group M, 127 cases) and after final follow-up CAG in patients treated by percutaneous transluminal coronary angioplasty (PTCA) (group B, 95 cases). There were 33 AMIs, including 5 deaths (22/127, 17.3%, in group M vs 11/95, 11.6%, in group B; p<0.01) and 189 UAPs (105/127, 82.7%, in group M vs 84/95, 88.4%, in group B; NS). High-grade stenoses (>75%) were found in 76 (59.8%) patients in group M, of which 41 lesions (54%) resulted in acute coronary syndromes (ACSs). In group M, ACSs resulted from insignificant stenosis (< or =50%) in 67 (53%) patients and from significant stenosis (>50%) in 60 (47%) patients. In group B, ACSs resulted from insignificant stenosis in 78 (82%) patients and from significant stenosis in 17 (18%) patients. Out of 95 PTCA sites, high-grade restenosis occurred in 3 lesions and ACSs (2 AMI, 14 UAP) in 16 (16.8%). We conclude that ACSs are more likely to develop from insignificant lesions than from significant lesions. High-grade stenoses are prone to become occlusive lesions and PTCA reduces this potential risk. Most target sites of PTCA that escaped restenosis were stable in the long term.

Aged↗
PubMed1998

Juvenile symptomatic Rathke's cleft cyst--case report.

A 14-year-old girl presented with a rare symptomatic Rathke's cleft cyst manifesting as diabetes insipidus and growth retardation. Neuroimaging demonstrated the suprasellar cyst. Computed tomography showed the cyst as an isodense area with enhancement, and magnetic resonance imaging showed an hyperintense area on both T1- and T2-weighted images. Histological examination showed the cyst was consistent with Rathke's cleft cyst. Symptomatic Rathke's cleft cysts usually occur in middle-aged adults. Juvenile cases tend to present with diabetes insipidus, and the cyst content may include more mucopolysaccharides or hemosiderin degradation products.

Adolescent↗
PubMed1998

Newly designed computer controlled knee-ankle-foot orthosis (Intelligent Orthosis).

The authors have developed a knee-ankle-foot orthosis with a joint unit that controls knee movements using a microcomputer (Intelligent Orthosis). The Intelligent Orthosis was applied to normal subjects and patients, and gait analysis was performed. In the gait cycle, the ratio of the stance phase to the swing phase was less in gait with the knee locked using a knee-ankle-foot orthosis than in gait without an orthosis or gait with the knee controlled by a microcomputer. The ratio of the stance phase to the swing phase between controlled gait and normal gait was similar. For normal subjects the activity of the tibialis anterior was markedly increased from the heel-off phase to the swing phase in locked gait. The muscle activities of the lower limb were lower in controlled gait than in locked gait. The ground reaction force in locked gait showed spikes immediately after heel-contact in the vertical component, and unusual patterns were observed at heel-contact in the sagittal and lateral component. Therefore, compared to locked gait, gait with the Intelligent Orthosis is smooth and close to normal gait from the viewpoint of biomechanics. Even in patients with muscle weakness of the quadriceps, control of the knee joint using the Intelligent Orthosis resulted in a more smooth gait with low muscle discharge.

Adult↗
PubMed1998

Total structures of colistin minor components.

Structural characterization of the colistin (CL) components were carried out using Frit-fast atom bombardment liquid chromatography/mass spectrometry (Frit-FAB LC/MS), tandem mass spectrometry (MS/MS) and the amino acid analysis proposed by MARFEY, and the total structures of 4 minor components including the absolute configuration of the constituent amino acids were proposed. The structures of the minor components were the same as those of the main component colistin A or B except that L-leucine is replaced by L-valine or L-isoleucine.

Anti-Bacterial Agents↗
PubMed1998

[Carbon monoxide concentrations during low flow anesthesia].

Elevated carbon monoxide (CO) concentrations have been reported during general anesthesia using inhaled anesthetics. In order to assess the safety of low flow anesthesia, we examined CO concentrations in anesthesia circuit during low flow anesthesia. Thirty patients were randomly divided into two groups. Anesthesia was induced with intravenous thiopental 5 mg.kg-1 and maintained with oxygen 2 l.min-1, nitrous oxide 4 l.min-1 and isoflurane (group H) or oxygen 0.5 l.min-1, nitrous oxide 0.5 l.min-1 and isoflurane (group L). The concentrations of CO in exhaust gas of anesthetic gas monitor were examined by CO sensor (XC-341, Shinkosumosudenki, Tokyo) and COHb was analyzed. The concentrations of CO in group L were significantly higher than in group H. The highest value, however, was 30 ppm. The COHb levels were slightly higher in group L, but the highest value was 2.1%. We consider that these results show no clinical risk and low flow isoflurane anesthesia may be performed safely. Measuring the CO concentrations is helpful for the safety of low flow anesthesia.

Aged↗
PubMed1998

[Bronchodilator aerosol propellant interferes with an photoacoustic spectrophotometer respiratory gas analyzer].

A patient with bronchial asthma was scheduled for an operation under nitrous oxide-isoflurane anesthesia. We monitored isoflurane concentrations continuously using an anesthetic gas analyzer (BK 1304). Upon puffing procaterol hydrochloride aerosol for 4 times, the analyzer showed a rapid increase in end-tidal isoflurane concentration. The BK 1304 uses infrared photoacoustic spectrophotometry and it is susceptible to interferences caused by Freon propellants in bronchodilator aerosols. We should take care in monitoring inhalational anesthetics when using aerosols containing Freon propellants.

Aerosols↗
PubMed1998

[Carbon monoxide in the expiratory gas during laparoscopic surgery].

One of the complications of laparoscopic surgery is carbon monoxide (CO) production under the use of electrocautery. We experienced a case in which high levels of CO were detected in the expiratory gas. An 80-year old, 33 kg female was scheduled for laparoscopic nephrectomy. Anesthesia was induced with thiopental and vecuronium and maintained with nitrous oxide 60% in oxygen and isoflurane. The concentrations of CO in the anesthetic circuit were examined with CO sensor (XC-341, Shinkosumosudenshi, Tokyo). The CO concentrations were not detected at the start of operation. About 140 minutes after carbon dioxide pneumoperitoneum, the CO concentration increased up to 170 ppm accompanying a high Paco level. The high concentrations, however, decreased immediately after ending of pneumoperitoneum. The HbCO levels were unchanged. Subcutaneous emphysema was noted at the end of surgery. This is because CO is more absorbable in the subcutaneous tissue than in the peritoneal cavity. We consider that CO was absorbed in subcutaneous emohysema during pneumoperitoneum and exhausted in the expiratory gas. When subcutaneous emphysema occurred during laparoscopic surgery, we should be aware of absorption of CO.

Aged↗
PubMed1997

Improvement of chemical analysis of antibiotics. XXIII. Identification of residual tetracyclines in bovine tissues by electrospray high-performance liquid chromatography-tandem mass spectrometry.

To reliably identify the residual tetracycline antibiotics (TCs), oxytetracycline (OTC), tetracycline, chlortetracycline (CTC) and doxycycline (DC), in bovine tissues, we have established a confirmation method using electrospray ionization liquid chromatography-tandem mass spectrometry (ESI LC-MS-MS) with daughter ion scan. All TCs gave [M+H-NH3]+ and [M+H-NH3-H2O]+ as the product ions, except for DC when [M+H]+ was selected as the precursor ion. The combination of C18 cartridge clean-up and the present ESI LC-MS-MS method can reliably identify TCs fortified at a concentration of 0.1 ppm in bovine tissues, including liver, kidney and muscle, and has been successfully applied to the identification of residual OTC in bovine liver and residual CTC in bovine muscle samples previously found at concentrations of 0.58 ppm and 0.38 ppm by LC, respectively.

Animals↗
PubMed1997

Pulse-spray thrombolysis in acutely obstructed coronary artery in critical situations.

Pulse-spray thrombolysis (PST) was performed to treat large coronary thrombus in 3 patients in critical situations. The originally developed pump system and a custom infusion catheter (SciMed/Boston Scientific, Maple Grove, MN) were used in combination. Case 1, a 48-yr-old male with extensive anterior myocardial infarction, failed to be recanalized by systemic thrombolysis. He underwent emergent coronary angiography, which revealed proximal occlusion of a large left anterior descending artery (LAD). TIMI 3 flow was achieved after 20 min with 200,000 units of urokinese by PST, followed by balloon angioplasty. In case 2, a 57-yr-old male, subacute stent thrombosis occurred 4 days after two and a half Palmatz-Schatz stents were implanted in mid-LAD. TIMI 3 flow was recovered at 20 min with 240,000 units of urokinese and an additional 72,000 units of rt-PA, followed by redilatation with a quarter-size larger balloon than that used in stent deployment. In case 3, a 70-yr-old male, during ultrasound study for unstable angina, a massive thrombotic complication occurred which occluded the left main trunk. PST was immediately performed under cardiac resuscitation, and the patient recovered from shock after 15 min. TIMI 3 flow was restored after 25 min. Two Palmatz-Schatz stents were implanted after thrombus completely disappeared. There were no complications, including distal embolization, intimal dissection, or bleeding. There was also no recurrence of the ischemic event. PST may be considered a potential treatment modality for coronary artery disease where large thrombus plays a major role.

Aged↗
PubMed1997

Impairment of endothelium-dependent relaxation of rabbit aortas by cigarette smoke extract--role of free radicals and attenuation by captopril.

The aim of this study was to examine the effects of the water soluble component of cigarette smoke extract (CSE) on endothelium-dependent relaxation (EDR) of isolated rabbit aortas. The incubation with CSE was found to inhibit EDR in a dose-dependent manner. Co-incubation of the aortic strips with superoxide dismutase (SOD), N-acetylcysteine, glutathione or dimethyl sulfoxide (DMSO), free radical scavengers, attenuated the CSE-induced inhibition of the arterial relaxation. Co-incubation of the strips with captopril (3 mM), an angiotensin converting enzyme inhibitor, also attenuated CSE-induced impairment of vasorelaxation. In parallel experiments using cultured human endothelial cells, CSE suppressed endothelial release of NOx, stable metabolites of nitric oxide (NO). SOD, DMSO and captopril attenuated the suppression of NO production by CSE in association with reduction of free radicals, superoxide anions and hydroxyl radicals, in CSE solution. Neither lactate dehydrogenase release from the cultured endothelial cells nor cell death estimated by trypan blue exclusion test was found after the incubation of the cultured endothelial cells with CSE. The results indicate that free radicals in CSE induce the impairment of EDR, which may be partly due to suppression of NO production and is not due to non-specific cytotoxicity by CSE. Captopril attenuates CSE-induced endothelial dysfunction partly through scavenging free radicals.

Acetylcysteine↗
PubMed1997

Effects of lidocaine on salicylate-induced discharge of neurons in the inferior colliculus of the guinea pig.

Using the extracellular recording method, the effects of lidocaine (a local anesthetic known to relieve tinnitus) on discharge of inferior colliculus (IC) neurons of the guinea pig were studied before and after salicylate (200 mg/kg) administration. The salicylate-induced discharge was inhibited by intravenous injection of lidocaine at a concentration (1 mg/kg) clinically used for treating tinnitus. IC neurons could be classified into two groups according to the difference in sensitivity to lidocaine: (1) weakly-sensitive neurons and (2) highly-sensitive neurons. In weakly-sensitive neurons, the duration of the lidocaine effect lasted for less than 5 min, and the inhibitory action on the discharge of neurons was greater when the latency to sound stimulus became longer. In highly-sensitive neurons, on the other hand, the activity of neurons was almost completely inhibited for longer than 30 min, irrespective of the latency to sound stimulus. The clinical relevance of these types of neurons is discussed.

Action Potentials↗
PubMed1997

Methotrexate maintains bone mass by preventing both a decrease in bone formation and an increase in bone resorption in adjuvant-induced arthritic rats.

We examined the effects of low doses methotrexate (MTX) and indomethacin (IND) on bone mass and turnover in normal male Sprague-Dawley rats and those with adjuvant-induced arthritis. Normal and the adjuvant (heat-killed mycobacterium)-injected rats, 6 weeks of age, were given MTX at daily doses of 0.05, 0.1, or 0.2 mg/kg body weight (BW) or IND at a daily dose of 1.0 mg/kg BW. Rats were killed at the start, or at 14 and 28 days. In normal rats, the administration of these agents did not change the lumbar and femoral BMD values, nor did the serum osteocalcin or urinary deoxypyridinoline (D-Pyr) levels. Lumbar trabecular osteoclast number (Oc.N/BS) and osteoclast surface (Oc.S/BS) were decreased in the rats given IND. In the arthritic rats, the administration of MTX did not prevent an early increase of paw edema in the adjuvant-injected limb, but late inflammatory edema was alleviated in the non-injected limb. However, MTX administration at a dose of 0.1-0.2 mg/kg BW maintained an age-dependent increase in the lumbar and femoral BMD values. While serum osteocalcin levels were decreased and urinary D-Pyr values were increased in the arthritic control rats, these bone markers remained at the levels of the normal rats. Decreases in mineral apposition rate (MAR) and bone formation rate (BFR/BS) and increases in the trabecular Oc.N/BS and Oc.S/BS values were prevented by MTX. While IND almost completely prevented inflammatory paw edema, it did not improve the parameters of bone formation. An increase in osteoclasts was prevented and the osteopenia in the lumbar and the femoral bone was only partially prevented by IND. These data suggest that MTX improves bone mass and turnover in the arthritic rat, in which several cytokines that affect bone cells are involved. An increase in bone resorption may be due to prostaglandins, but bone formation defect was suggested to be due to other cytokines such as IL-1, IL-6, and TNF-alpha in this model.

Animals↗
PubMed1997

Myelomonoblastic leukaemia cells carrying the PEBP2beta/MYH11 fusion gene are CD34, c-KIT+ immature cells.

To clarify the aspects affected by the PEBP2beta/MYH11 fusion gene involved in the inv(16), we analysed immunophenotypes in myelomonoblastic leukaemias. We found high expressions of CD34 and c-KIT antigens in myelomonoblastic cells from all patients carrying this fusion gene, including two with M4 and one CML blastic phase, in contrast to those with M4 without the fusion gene. These findings indicate that immunophenotyping is useful for detecting a leukaemia with the fusion gene in myelomonoblastic leukaemias and that the PEBP2beta/MYH11 gene is involved in immature cells expressing CD34 and c-KIT antigens.

Antigens, CD34↗
PubMed1997

Common clonal origin of lymphocytes and plasma cells in splenic lymphoma with villous lymphocytes.

In two-thirds of patients with splenic lymphoma with villous lymphocytes (SLVL) a small amount of M-protein can be detected in association with the presence of plasma cells in the peripheral blood (PB) and/or bone marrow (BM). However, it is not known whether lymphoma cells and plasma cells originate from the same clone. In this report we describe a case of SLVL which was characterized by the presence of marked monoclonal gammopathy (IgG-kappa 90 g/l) and increased plasma cells in the BM. In an attempt to elucidate the origin of lymphoma cells and plasma cells, we performed morphological, cytogenetic and molecular studies on PB mononuclear cells (PBMNC) without plasma cells and BMMNC containing 10% plasma cells from this patient. Immunofluorescence showed that lymphoma cells and plasma cells were positive for cytoplasmic gamma heavy and kappa light chains. Well-developed endoplasmic reticulum was observed in the cytoplasmic organelles of PBMNC using an electron microscope. The mean IgG concentration in the 3 d supernatant cultures of PBMNC was 374 +/- 24 microg/l. More than 50% PBMNC differentiated into plasmacytoid cells in 6 d of liquid culture with IL-3 and IL-6. Analysis by two-colour FISH revealed that karyotypic abnormalities of monosomy X and trisomy 17 existed simultaneously in both lymphoma cells and plasma cells. JH gene rearranged bands from PBMNC and BMMNC by Southern blot hybridization were identical, whereas DNAs from PBMNC failed to hybridize with the Cmu probe. These observations strongly suggest that lymphoma cells and plasma cells originate from the same clone, and that plasma cells, as well as lymphoma cells, which have undergone class switch recombination, could produce IgG type M-protein in this case.

Aged↗
PubMed1997

Single lead atrial synchronous ventricular pacing in Japanese patients with complete atrioventricular block.

The purpose of this study was to review our experience with atrial synchronous ventricular pacing devices (THERA VDD pacing systems, Medtronic, Inc., U.S.A.) using single atrioventricular leads in Japanese patients with complete atrioventricular block and normal sinus function. Twenty patients with a mean age of 55 +/- 13 years underwent implantation of VDD pacemakers. At implantation the amplitude of atrial signals in the supine position during normal breathing, which was measured directly using an external pacing system analyzer, ranged from 1.8 to 5.8 mV with a mean amplitude of 3.4 +/- 1.4 mV. Atrial amplitudes did not change during deep breathing (3.3 +/- 1.1 mV) or in the semi-Fowler position (3.4 +/- 1.6 mV). Atrial oversensing or undersensing was not observed in any of the patients. During a follow-up period, the percentage of atrial synchronization was >95% in 19 patients, and none of the patients had pacemaker related tachycardia or pacemaker related complications. These results were promising enough to warrant the extension of the clinical use of the VDD pacemaker.

Adult↗
PubMed1997

[A case of the tuberculous abscess in the abdominal wall].

A case of the tuberculous abscess in the abdominal wall is reported. A 84-year-old female was admitted to our hospital with evaluation of soft tumor at the left lower abdomen. She has a mass in the abdominal wall measuring 4 cm in diameter, and abscess in the abdominal wall was detected by ultrasonogram and CT. The confirmed diagnosis of abdominal wall tuberculosis was made by means of bacterial culture and polymerase chain reaction (PCR method) of the aspirated fluid from a mass. Multiple calcified lesions on the abdominal X-ray were seen, which were thought to past history of tuberculous peritonitis. Antituberculosis therapy of three-drug regimens was not effective. Four month later, resection of the abscess was then performed. Adhesion was demonstrated between greater omentum and peritoneum, therefore the abscess in the abdominal wall was considered to arise and advance directly from the abdominal cavity.

Abdominal Muscles↗