Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 397 records · Page 22Linked to original sources

PubMed1999

Pathophysiological roles of endothelin-1 in Dahl salt-sensitive hypertension.

The purpose of the present experiment was to study the pathophysiological roles of endothelin-1 (ET-1) in salt-sensitive hypertension with the use of Dahl salt-sensitive (DS) and salt-resistant (DR) rats. PreproET-1 mRNA expression was determined by reverse transcription-polymerase chain reaction. In the kidney, expression of preproET-1 mRNA was greater in DS rats on a normal salt diet compared with DR rats of the same age. In DS rats, the level of preproET-1 mRNA expression in kidney had a significant correlation with systolic blood pressure. The expression of preproET-1 mRNA in aorta and kidney was increased by 3-week high salt intake in DS rats but not in DR rats. Expression of preproET-1 mRNA and ET-1 levels in left ventricle was exaggerated by high salt intake in DS rats. However, there was no significant difference in plasma ET-1 levels between DS and DR rats regardless of salt intake. Pressor response curves for ET-1 in DS rats with or without high salt intake were significantly shifted to the left compared with those in DR rats. A single oral dose (3 to 10 mg/kg) of J-104132 (L-753 037), a potent, orally active mixed endothelin A and B (ET(A)/ET(B)) receptor antagonist, reduced blood pressure to normotensive levels in DS rats with high salt intake, and its action was maintained for >/=24 hours. In DS rats with normal salt intake, J-104132 (10 mg/kg) slightly but significantly decreased blood pressure. DR rats did not show obvious depressor responses to J-104132 (10 mg/kg) regardless of salt intake. These results suggest that ET-1 acts as one of the pathophysiological factors in the development and maintenance of salt-sensitive hypertension, and a mixed ET(A)/ET(B) receptor antagonist could be useful in the treatment for salt-sensitive hypertension.

Animals↗

PubMed1999

Suppression of arthritic bone destruction by adenovirus-mediated csk gene transfer to synoviocytes and osteoclasts.

Rheumatoid arthritis (RA) is characterized by a chronic inflammation of the synovial joints resulting from hyperplasia of synovial fibroblasts and infiltration of lymphocytes, macrophages, and plasma cells, all of which manifest signs of activation. Recent studies have revealed the essential role of osteoclasts in joint destruction in RA. Src family tyrosine kinases are implicated in various intracellular signaling pathways, including mitogenic response to growth factors in fibroblasts, activation of lymphocytes, and osteoclastic bone resorption. Therefore, inhibiting Src activity can be a good therapeutic strategy to prevent joint inflammation and destruction in RA. We constructed an adenovirus vector carrying the csk gene, which negatively regulates Src family tyrosine kinases. Csk overexpression in cultured rheumatoid synoviocytes remarkably suppressed Src kinase activity and reduced their proliferation rate and IL-6 production. Bone-resorbing activity of osteoclasts was strongly inhibited by Csk overexpression. Furthermore, local injection of the virus into rat ankle joints with adjuvant arthritis not only ameliorated inflammation but suppressed bone destruction. In conclusion, adenovirus-mediated direct transfer of the csk gene is useful in repressing bone destruction and inflammatory reactions, suggesting the involvement of Src family tyrosine kinases in arthritic joint breakdown and demonstrating the feasibility of intervention in the kinases for gene therapy in RA. off

Adenoviridae↗

PubMed1999

Usefulness of cardiopulmonary bypass in reconstruction of inferior vena cava occupied by renal cell carcinoma tumor thrombus.

UNLABELLED: Aggressive surgical treatment in renal cell carcinoma is still controversial. The aim of this paper is to assess inferior vena caval (IVC) reconstruction for suprahepatic vena caval renal cell carcinoma (RCC) tumor thrombus. Twelve patients with suprahepatic vena caval thrombus from renal cell carcinoma who underwent surgical repair with cardiopulmonary bypass were evaluated. The vena caval defect was reconstructed by direct suture, patch repair, or graft replacement. Of 12 patients undergoing partial cardiopulmonary bypass, tumor thrombus extended to the junction of the hepatic vein in three patients and to the right atrium in one. Tumor thrombus was removed manually or with balloon catheter. Tumor thrombus in the right atrium was removed during electrical ventricular fibrillation. Repair of the IVC was performed by direct suture of the IVC wall in two patients, patch repair with expanded polytetrafluoroethylene (EPTFE) graft in seven, and graft replacement with an EPTFE graft in three. There were no operative deaths and the only postoperative complication was one patient death from pulmonary emboli. The four patients with nonlocalized disease died within 2 years, but four patients lived for more than 3 years postoperatively. Survival was 37.5% at 3 years and 18.8% at 5 years by the Kaplan-Meier's method. CONCLUSIONS: (1) Partial cardiopulmonary bypass is useful for the control of bleeding when tumor thrombus in the IVC extends to the junction of the hepatic vein. (2) Nephrectomy with tumor thrombectomy of the IVC is valuable, and long-term survival is possible in patients without distant metastases or regional lymph node metastases.

Adult↗

PubMed1999

Primary venous aneurysms--case reports.

Venous aneurysms are rare lesions that may be the source of pulmonary emboli and can result in death. The authors have recently treated several patients who had venous aneurysms of the upper extremity, lower extremity, and jugular system. Venous aneurysms usually appear to have a safe natural history in these locations, although all of the reported patients required surgery after the development of symptoms owing to complaints of pain, and/or cosmetic appearance, and/or a diagnosis of thrombosis. These cases are presented, along with a review of venous aneurysms occurring at other sites and their causes.

Adult↗

PubMed1999

Studies of the active substances in herbs used for hair treatment. III. Isolation of hair-regrowth substances from Polygara senega var. latifolia TORR. et GRAY.

Four active principles, 1, 2, 3 and 4, were isolated from Polygara senega var. latifolia TORR. et GRAY by a combination of partition and column chromatography on silica gel and octadecyl silica gel (ODS), monitored by a hair-regrowth activity assay. Compounds 1, 2, 3 and 4 were identified as senegose A, senegin II, senegin III, and senegasaponin b by comparison of their spectral data with those of authentic samples.

Animals↗

PubMed1999

Evaluation of Mycoplasma hyopneumoniae inactivated vaccine in pigs under field conditions.

An inactivated vaccine prepared from broth culture supernatant of Mycoplasma hyopneumoniae with an aluminum adjuvant was evaluated in three herds (herd A: specific pathogen-free herd, herd B: high health status herd with no clinical signs of respiratory infection, herd C: low health status herd with serious epidemiological and economical problems). A total of 212 pigs from the three herds were divided into two groups. One group was injected twice with the vaccine at 4-week intervals and the other was a control group. No adverse reactions were noted following the vaccinations either systematically or locally in any of the vaccinated pigs from any of the herds. In herd A, the vaccination provided antibody response within 4 weeks after the second vaccination and antibody responses continued for more than 12 weeks. In herds B and C, the number of pigs with lung lesions, mean percentage of lung lesions, and the numbers of M. hyopneumoniae recovered from pigs at slaughter in the vaccinated group were significantly (P < 0.05) reduced compared to the control group. Furthermore, vaccination resulted in improved average daily weight gain (ADG), improved feed conversion ratio (FCR), and improved days to market weight in herd C, whereas no difference in growth performance was shown in herd B. It is suggested that the inactivated vaccine prepared from broth culture supernatant of M. hyopneumoniae is effective in reducing clinical signs and lung lesions. Also, vaccination resulted in improved growth performance in herds where clinical signs and economic losses were significant.

Animals↗

PubMed1999

Binding characteristics of folate to high affinity folate binding protein purified from porcine serum.

High affinity folate binding protein (HFBP) in porcine serum was purified 2,000-fold to a specific activity of 1.4 nmol of tetrahydrofolic acid (THF) bound per mg of protein, using folic acid (FA) coupled EAH-Sepharose gel affinity chromatography. Binding activity of purified HFBP to folate was examined by ultrafiltration method linked to high-performance liquid chromatography with electrochemical detection or to liquid scintillation counting. Binding affinity of HFBP to folate was characterized by dissociation constants (Kd): 13, 17, and 31 pM for tritiated FA (3HFA), THF, and N5-methyltetrahydrofolic acid (5MF), respectively. FA, THF, and 5MF significantly inhibited binding of HFBP to 3HFA, and according to the magnitude of intensity of the binding inhibition, the order of affinity of each folate was confirmed to be FA > THF > 5MF. Binding activity was rather high and stable for THF and 5MF at pH ranging from 6.0 to 10.0. The binding activity, however, rapidly decreased at pH below 6.0 and over 10.0. No binding activity was observed pH below 3.0 and over 12. Gel filtration analysis showed that the prepared HFBP solution had specific binding activity at around 77 kDa of apparent molecular weight, which was 82 kDa by SDS-PAGE. It is considered that this specific and stable binding enables THF to distribute in porcine plasma.

Animals↗

PubMed1999

Diagnostic difficulty in polycystic ovary syndrome due to an LH-beta-subunit variant.

We initially failed to confirm a case of polycystic ovary syndrome (PCOS) because underestimation of LH concentrations due to a variant form of this hormone resulted in a misleadingly low LH/FSH ratio. A 26-year-old woman presented to our hospital with infertility. Given the presence of bilateral polycystic ovaries, oligomenorrhea and hirsutism. PCOS was suspected, but a normal LH/FSH ratio as measured by RIA led to diagnostic problems. When we remeasured LH and FSH using a chemical luminescence enzyme immunoassay (CLEIA), the ratio of the LH concentration measured by RIA to that measured by CLEIA was 0.29, and the ratio of LH to FSH measured by CLEIA was 3.3 compared with 0.81 measured by RIA. We then diagnosed PCOS. The point mutations Trp8 to Arg8 and Ile15 to Thr15 in the LH subunit were detected in the corresponding gene. The patient's LH status represented variant and wild-type LH equally. She was therefore diagnosed as heterozygous for the mutant LH-beta. Histologic assessment of ovarian tissue after laparoscopic biopsy was compatible with a polycystic ovary.

Adult↗

PubMed1999

In vitro toxicity of gallium arsenide in alveolar macrophages evaluated by magnetometry, cytochemistry and morphology.

Gallium arsenide (GaAs), a chemical compound of gallium and arsenic, causes various toxic effects including pulmonary diseases in animals. Since the toxicity is not completely investigated, GaAs has been used in workplaces as the material of various semiconductor products. The present study was conducted to clarify the toxicity of GaAs particles in the alveolar macrophages of hamsters using magnetometry, enzyme release assays and morphological examinations. Alveolar macrophages obtained from hamsters by tracheobronchial lavage and adhered to the disks in the bottom of wells were exposed to ferrosoferric oxide and GaAs particles. Ferrosoferric oxide particles were magnetized externally and the remanent magnetic field was measured. Relaxation, a fast decline of the remanent magnetic fields radiated from the alveolar macrophages, was delayed and decay constants were decreased dose-dependently due to exposure to GaAs. Because the relaxation is thought to be associated with cytoskeleton, the exposure of GaAs may have impaired the motor function of them. Enzyme release assay and morphological findings indicated the damage to the macrophages. Thus the cytotoxicity causes cytostructural changes and cell death. According to DNA electrophoresis and the TUNEL method, necrotic changes occur more frequently than apoptotic changes.

Animals↗

PubMed1999

Primary hypomagnesemia caused by isolated magnesium malabsorption: atypical case in adult.

Isolated magnesium malabsorption is a rare disorder, which bas been described in no more than 30 patients worldwide. Patients with this disorder typically present with convulsion and diarrhea in early infancy. Hypomagnesemia and hypocalcemia were found in a 35-year-old man with muscle cramps, who bad been diagnosed as primary hypoparathyroidism. Oral magnesium therapy corrected the low serum calcium, magnesium and parathyroid hormone levels. We report an atypical case of isolated magnesium malabsorption in an adult.

Administration, Oral↗

PubMed1999

Central diabetes insipidus with Behçet's disease.

We encountered a case of Behçet's disease complicated with central diabetes insipidus. A hypothalamopituitary dysfunction is rare in Behçet's disease; only three cases of this association have been reported in the literature. Magnetic resonance imaging of the brain showed a dilatation of the left Sylvian vein and thickening of the pituitary stalk, which suggested intracranial vasculitic processes and lymphocytic infundibuloneurohypophysitis. The possible relationship of this disease combination is discussed as a form of autoimmune disease.

Adult↗

PubMed1999

An analysis of management of private dental clinics in Japan from the survey of the current economy of medicine and dentistry.

We analyzed the current state of management of private dental offices in Japan using the 11th Survey of the Current Economy of Medicine and Dentistry conducted in September of 1997. The analysis was mainly performed by comparing the survey in 1997 with the survey conducted in 1989. The results show the medium-term tendencies in dental management. We also compared the data from dental offices with those from private medical offices without facilities for inpatients. The following are the results: the average income from dental practice for a dental office in 1997 was 4,050,000 yen, a decrease of 4.9% (about 210,000 yen) compared with the average income in 1989. The average income from treatment covered by insurance in 1997, which accounted for most of the total income, was 3,540,000 yen, a decrease of 2.8% compared with that in 1989. The average income from non-insured treatment was 490,000 yen, which was also a decrease of 17.4%. The average income from medical practice for a medical office in 1997 was 1,970,000 yen more than the average income from dental practice of the same year. The average medical practice expenses and the average balance in medicine were higher than those in dentistry by 1,360,000 yen and by 600,000 yen respectively. Although the average income from medical practice slightly increased, the average wage costs increased by as much as 42.8%, resulting in a decrease of 21.2% in the average balance. Dental offices attempted to weather the decreased income from dental practice by raising the average fee paid by an insured patient. The analysis in the present study suggested that a decreasing number of patients and increasing dental practice expenses diminished the balance.

Dental Clinics↗

PubMed1999

Increase of the cellular growth of old human diploid fibroblasts by radical scavenger: methanolic extract of broad beans.

The methanolic extract from broad beans (MEBB), which is comprised of phenolic compounds, has free-radical scavenging activity. The effects of MEBB on cytosolic antioxidant enzymes and cell proliferation were examined in cultures of old (78-84% life-span completed) WI-38 human diploid fibroblasts. Because catechin is polyphenol and has radical scavenging activity, it was used as the control in experiments. We observed that MEBB increased cellular growth when added to the cell culture. In MEBB at 40 and 120 micrograms/mL, the cell proliferation increased by 14 and 27%, respectively, as compared to the control. In catechin, cell proliferation increased as well. Regarding cytosolic glutathione peroxidase (GSH-Px) activity, treatment of old cells with MEBB at 40 and 120 micrograms/mL resulted in decreases as compared to the control. In contrast, catechin showed no similarities to the modification of GSH-Px activity. Cytosolic SOD activity was increased by treatment with 40 micrograms/mL MEBB, and the activity showed a gradual decrease with increased MEBB concentrations. A similar trend occurred in the cells treated with catechin (4-20 microM). These results suggest that cytosolic antioxidant enzyme activities in old cells may be modulated by MEBB treatment. We conclude that there may be a relation between the optimum MEBB concentration for the increase of cellular growth and the MEBB concentration required to exhibit a decrease in GSH-Px activity.

Antioxidants↗

PubMed1999

[Surgical strategy for invasive pulmonary and mediastinal tumors requiring superior vena cava reconstruction].

During the past 16 years, 22 patients were operated on concomitantly with superior vena cava (SVC) reconstruction in our university hospital. Among them, 19 patients had anterior mediastinal tumor and 3 advanced lung cancer. They were 13 males and 9 females, ranging in age from 16 to 70 (mean, 51.4) years. Severe SVC syndrome was found in 10 cases of them. The anterior mediastinal tumors consisted of invasive thymoma in 10 cases, thymic Hodgkin's disease in 2, seminoma in 2, and thymic cancer, thymic carcinoid, thyroid cancer, metastasis of chondrosarcoma and yolk sac tumor in each one. Regarding SVC reconstruction, anatomical bypass was performed in 18 cases, in addition to a radical resection of the tumor. The left innominate vein was reconstructed in 5, the right innominate vein including SVC in 4 and bilateral veins in 9. Extra-anatomical bypass was performed in 4 cases with unresectable tumors because of severe SVC syndrome. Subclavian-femoral vein bypass was performed in one and internal jugular-femoral vein bypass in 3. In anatomical bypass, 7 cases have been alive now though 11 died, and graft patency rate was 82% in the right and 38% in the left. All 4 cases with extraanatomical bypass showed improvement of SVC syndrome, but died one to seven months postoperatively. In conclusions, radical operation with reconstruction of SVC was effective to long-term survival and improvement of SVC syndrome. Extraanatomical bypass improved postoperative quality of life remarkably.

Adolescent↗

PubMed1999

Efficacy of initial controlled perfusion pressure for ischemia-reperfusion injury in a 24-hour preserved lung.

In lung transplantation, the safety period of the ischemic time of the graft is within 6 hours. Because of the problem of donor shortage, it is essential to extend the safety period of the preservation time of the donor lung. However, the longer the preservation time is, the more severe is the resulting ischemia-reperfusion injury. This study was designed to evaluate the efficacy of initial controlled perfusion pressure in the reduction of ischemia-reperfusion injury in a 24-hour preserved lung. Japanese white rabbit lungs were flushed with a low-potassium dextran solution (4C, 500 ml) after injection of prostaglandin E1 (20 microgram, bolus via PA) and submersed in the same solution for 24 hours at 4C. After preservation, the left lung was reperfused using an extracorporeal lung perfusion model which comprised of a closed circuit combined with a membrane deoxygenator. Assessment of lung function included gas analysis of influent and effluent blood and mean pulmonary artery perfusion pressure. Then the lung wet/dry weight ratio was calculated. In group I of the control group (n=6), the left lung was reperfused immediately following flushing (without preservation) at a flow rate of 50 ml/min for 60 minutes. In groups II and III, grafts were stored for 24 hours. In group II, grafts (n=6) were reperfused at a flow rate of 50 ml/min for 60 minutes. In group III (n =6), the flow rate was controlled by maintaining the perfusion pressure below 30 mmHg during the initial 5 minutes and was increased to 50 ml/min for the subsequent 60 minutes. In group II, the mean pulmonary artery pressure during perfusion increased rapidly, and oxygenation deteriorated. All grafts developed pulmonary edema within 12 minutes after reperfusion. Examination of the specimen revealed that the peripheral lung was not perfused. In group III, the mean pulmonary artery perfusion pressure was maintained below 30 mmHg, and oxygenation was preserved sufficiently throughout the experiment (delta PO2 > 100 mmHg) with no significant difference from control values. In conclusion, ischemia-reperfusion injury of the 24-hour preserved lung was attenuated prominently by controlling initial perfusion pressure for 5 minutes.

Analysis of Variance↗

PubMed1999

The effect of direct lidocaine injection into the clamped aortic segment on the spinal evoked potential: early diagnosis for spinal cord ischemia.

PURPOSE: The aim of this study was to identify a method to determine whether segmental artery reconstruction was indicated during aortic clamping. METHOD: Spinal cord evoked potential (SCEP) and regional spinal blood flow were studied in 24 adult dogs. Using the left heart bypass technique, aortic clamping divided the aorta into thoracic, abdominal, and terminal segments. After the occlusion of the descending aorta and discontinuation of the perfusion to the abdominal segment, animals were assigned to four groups: no treatment with perfusion to the terminal aorta (group IA), no treatment with cessation of bypass (group IB), 5% lidocaine administration (5 mg/kg) into the abdominal segment with perfusion to the terminal aorta (group IIA), and lidocaine administration with cessation of bypass (group IIB). RESULTS: Cessation of bypass reduced spinal blood flow and SCEP amplitude. Lidocaine injection allowed for a significant rapid decrease in SCEP amplitude in group IIB compared with group IB (24.2% +/- 13.4% versus 92.3% +/- 33.2%; p = 0.0039). The degree of spinal blood supply was reflected immediately in the magnitude of SCEP amplitude change by the direct lidocaine injection. (group IB versus group IIB; p = 0.023). CONCLUSION: The direct injection of lidocaine into the clamped aorta results in a rapidly change in SCEP in the threat of ischemia and can be used to make an early detection of the segmental arteries perfusing to the spinal cord.

Analysis of Variance↗

PubMed1999

[In vitro activities of 23 antimicrobial agents against 4,993 gram-positive and gram-negative bacterial strains isolated from multicenter of Japan during 1994--in vitro susceptibility surveillance.Levofloxacin-Surveillance Group].

In a surveillance study conducted during 1994 at 24 medical institutes from different geographical areas of Japan, the susceptibility of clinical isolates to twenty three comparative agents, such as ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin, ampicillin, clavulanic acid/amoxicillin, oxacillin, piperacillin, cefaclor, cefotiam, cefdinir, cefclidin, ceftazidime, cefpirome, imipenem, aztreonam, vancomycin, minocycline, chloramphenicol, clarithromycin, sulfamethoxazole/trimethoprim, amikacin, and gentamicin, were tested by the standard broth micro-dilution method. A total of 4,993 isolates tested in this study included Streptococcus pneumoniae, methicillin susceptible Staphylococcus aureus (MSSA), methicillin resistant Staphylococcus aureus (MRSA), coagllase negative streptococci (CNS), Enterococcus faecalis, Enterococcus faecium, Enterobactericeae, Pseudomonas aeruginosa from patients with urinary tract infections or respiratory tract infections, and Haemophilus influenzae. For MSSA, S. pneumoniae, Enterobacteriaceae, and H. influenzae, more than 70% of the isolates was susceptible to fluoloquinolones. However, resistance occurred in more than 50% of MRSA and P. aeruginosa isolated from UTI. Fluoroquinolones were found to be effective against high level penicillin-resistant S. pneumoniae, the third generation cephem-resistant Enterobacteriaceae and ampicillin-resistant H. influenzae.

Anti-Bacterial Agents↗

PubMed1999

An availability of video-assisted thoracic surgery for the resection of pulmonary metastases.

We report the use of video-assisted thoracic surgery (VATS) as a treatment for pulmonary metastases. Eight patients with metastatic lung cancer were treated with VATS techniques. These patients included 5 males and 3 females whose ages ranged from 34 to 61 years (average: 47.4). Their primary diseases were seminoma (n = 3), renal cell carcinoma (n = 2), colon carcinoma (n = 1), mammary carcinoma (n = 1) and choriocarcinoma (n = 1). Computed tomography (CT) scans with current generation scanners were performed preoperatively and revealed one metastatic lesion in each of five cases and two lesions in each of the other three cases. In one case, one lesion was located in each of the lungs. Tumor size ranged from 5 to 30 mm in diameter, and all lesions were in the peripheral field of the lung. VATS was carried out with three surgical ports for three cases, two surgical ports for one case, and only one port for two cases. For all cases, an endo-stapler was utilized. In two cases, the preoperative point-marking technique for tumors was employed under the guidance of CT imaging. All patients were discharged from the hospital with no complications, and were followed up with no evidence of lung recurrence. Our criteria in selecting patients for the VATS removal of metastatic lung tumors are as follows: 1) tumors are less than 30 mm in diameter in the peripheral lung, 2) the number of tumors detected by CT scan, etc., is one or two. We conclude that VATS is a good candidate for the resection of lung metastases in the selected cases. Long term outcome remains to be solved in the future.

Adult↗