Biomedical subjects

M Okada

Publications and source records attributed to M Okada.

At least 1,099 records · Page 61Linked to original sources

PubMed1992

Amplification of nocturnal melatonin secretion in women with nocturnal hyperprolactinemia.

In order to assess the pathophysiological role of melatonin (MLT) in nocturnal hyperprolactinemia (NH), nocturnal serum MLT and prolactin (PRL) levels were measured in samples collected every 2h over a 12-hour period (2000h-0800h) from 5 normal women and 9 women with NH under physiological light/dark condition (lights off from 2100h to 0600h). Furthermore, differences in the PRL response to acute oral administration of MLT (1 mg or 5 mg) during the daytime between the 2 groups was studied. Nocturnal MLT levels in patients with NH were significantly higher (p < 0.02) than in normal women. The maximal PRL levels (52.6 +/- 26.7 ng/ml at 2400h) during the night in patients with NH were significantly higher (p < 0.05) and were reached 4h earlier than in normal women. The response to administration of 1 mg of MLT was not different between the 2 groups. However, administration of 5 mg of MLT to normal women resulted in a rapid and prominent PRL release, similar to that observed at nighttime in patients with NH. These results indicate that the abnormal PRL release in patients with NH is not due to higher sensitivity to MLT. However, the elevated MLT levels in patients with NH may be related to the neuroendocrine disorder.

Adult↗

PubMed1992

[A case of adenocarcinoma of lung cancer with multiple brain metastasis and lymphangitis carcinomatosa responding well to chemotherapy with carboplatin, etoposide and ifosfamide].

A 75-year-old male who suffered from adenocarcinoma of lung cancer with multiple brain metastases, developed left hemiplegia. After diagnosis, he was treated with 4,000 cGy whole brain radiation, but soon after advanced lymphangitis carcinomatosa set in and his general condition deteriorated. He was administered carboplatin combination with etoposide and ifosfamide. Lymphangitis carcinomatosa disappeared, and the main tumor of lung and brain metastases were not growing. We recommended carboplatin for an old patient or one in poor condition, because it had less cytotoxicity and retained the same antitumor activity compared with cisplatin.

Adenocarcinoma↗

PubMed1992

[Vincristine played a pivotal role in hematological remission of thrombotic thrombocytopenic purpura (T.T.P.)].

A case of thrombotic thrombocytopenic purpura (TTP), in which vincristine (VCR) administration played a pivotal role in achieving the hematological remission, is presented. A 40-year-old woman with a chief complaint of purpura was transferred for detailed examination of thrombocytopenia. The presence of hemolytic anemia, schistocytosis, febrile clinical course, renal dysfunction and neurological abnormalities made the basis of a diagnosis of TTP. Twelve courses of consecutive plasma exchange and plasma infusion, which amounted to a total of 120l of fresh frozen plasma, were performed without obvious hematological improvement. Therefore, VCR (2 mg) was infused in addition to the plasma exchange. Three days later, platelets responded remarkably. After 10 days of hematological improvement, relapse occurred. VCR was reinfused. However, the second VCR infusion alone was not able to elevate platelets. With concomitant use of significant amounts of plasma, the platelet count responded gradually. Hematological remission was obtained and has continued until now. The exact role of VCR for TTP is still unknown; however, VCR is suggested to be effective for TTP as in the case presented here.

Adult↗

PubMed1992

Effect and limitation of intra-aortic balloon pumping following valve replacement surgery.

To evaluate the effect and the limitation of intra-aortic balloon pumping (IABP) in patients with severe left ventricular failure (LVF) following valve replacement surgery, we assessed the results of 282 patients who underwent such surgery. Among 25 patients in whom IABP was used after valve replacement, 17 patients could be weaned from IABP, and 14 of them achieved long-term survival. The durations of IABP support for patients who were weaned from IABP were shortened and were mostly within 48 hours, whereas those in patients not weaned from IABP tended to be prolonged. Among 25 IABP patients, 8 had definite causes of LVF such as perioperative myocardial infarction, but the other 17 patients experienced LVF despite uneventful operation. In the latter group of patients, preoperatively depressed left ventricular function was observed in 10 patients. In the former group of patients, the duration of IABP was much longer, and the weaning rate, as well as survival rate, was significantly poorer. On the other hand, in the latter-group patients, the duration of IABP was shortened and the survival rate was excellent. In conclusion, IABP support for patients with postoperative LVF of unknown causes, which might include patients with preoperatively depressed left ventricular function, was sufficiently effective, whereas no significant effect of IABP was noted for patients experiencing LVF after definite and serious perioperative complications.

Adult↗

PubMed1992

[Use of heart rate variability and pulse wave velocity for diagnosing cardiovascular autonomic neuropathy].

Heart rate (HR) and arterial pulse wave velocity (PWV) were used for the evaluation of cardiovascular autonomic neuropathy. Data were analyzed from 30 patients with diabetes mellitus (aged from 13 to 75 years). Twenty healthy male subjects (aged from 22 to 44 years) were analyzed for computing normal values as well. After 15 minutes rest, electrocardiogram (ECG) of lead II and plethysmogram of finger tip were simultaneously recorded for each subject. The recording was first done in supine position for 120 seconds and subsequently in upright position for 40 seconds. HR was computed on the basis of consecutive pairs of R wave of the ECG. PWV was estimated by transit time from R wave peak to initial rise of pulse wave. Mean and coefficient of variation (CV) were obtained from the HR in the supine and upright positions respectively, and also from the PWVs. The influence of changing the position was evaluated by percentage of the difference (increasing rate). All the parameters were statistically tested for the difference between the patients with neuropathy and those without neuropathy. As the result, two parameters, that is, the CV of HR in the supine position and the increasing rate of PWV were found to be useful for diagnosing the cardiovascular autonomic neuropathy (p less than 0.05).

Adolescent↗

PubMed1992

The process of subretinal strand formation.

Surgically resected subretinal proliferative tissue (SRP) in proliferative vitreoretinopathy was examined by morphological and immunohistochemical methods. Membranous and strand-like SRPs were observed. Membranous SRP (4 cases) consisted of retinal pigment epithelial cells (RPEs) and a thin layer of extracellular materials. Strand-like SRP (14 cases) had a core, in which the proliferated cells were embedded among extracellular materials. RPEs and glial cells were found on the surface of the core. Immunohistochemical investigation revealed that the predominant cell components of the strand-like SRPs were RPEs and Müller cells, whereas membranous SRPs were composed mainly of RPEs. It was found that the majority of membranous and strand-like SRPs contained types I, III and IV collagens and fibronectin in the extracellular space. Based on the results of this study, a hypothetical process for the formation of SRP tissues was proposed.

Animals↗

PubMed1992

[Repeated blackout in a patient with accelerated idioventricular rhythm].

There has been no report that Accelerated Idioventricular rhythm (AIVR) causes a syncope attack. The patient described in this report is very rare because AIVR chronic without any heart diseases has been observed for 13 years, and because it is considered that AIVR is closely associated with his repeated blackouts. A 62-year-old male was admitted to our hospital because of repeated syncopal attacks. He reported that he occasionally felt lightheaded after strenuous lifting and pushing or pulling against resistance. We found that AIVR could produce a remarkable arterial pressure drop partly because of ventricular asynergy and loss of timed atrial contribution. Furthermore, we observed syncopal attacks during Valsalva maneuver and found abnormalities of baroreceptor reflex (Lack of reflex tachycardia and weakened evershoot phenomenon). It is concluded that AIVR is not a benign arrhythmia in this patient because it has been a possible cause of syncope attack due to systemic arterial pressure drop and baroreceptor abnormalities.

Accelerated Idioventricular Rhythm↗

PubMed1992

[A successful repair of the left ventricular rupture and tracheo-esophageal fistula complicated after mitral valve replacement--a case report].

A 59-year-old woman having mitral stenosis with left atrial thrombus, was admitted to our department and uneventful mitral valve replacement was performed. After weaning from the cardiopulmonary bypass, massive pericardial bleeding was encountered and the heart soon arrested. CPB was reinstituted after thirty minutes. The diagnosis was the left ventricular rupture (Miller Type III), and the direct closure was successfully performed. The patient was complicated with renal and heart failures, which were well managed by the peritoneal dialysis and intraaortic balloon pumping. Long-term intratracheal intubation, however, was required due to the respiratory failure, and tracheostomy was done on the seventeenth postoperative day. The patient was also complicated with mediastinitis, the cause of which was considered to be the tracheo-esophageal fistula (TEF) diagnosed by esophagoscopy and bronchoscopy. Gastrostomy and continuous mediastinal lavage were performed but the TEF was not closed. Thus, the direct suture of the esophageal fistula orifice and the resection of four tracheal rings followed by the direct end-to-end anastomosis were performed on the 102nd postoperative day. After the second operation, the patient greatly improved, and was discharged eighty-seven days later, presenting only slight LV posterior wall hypokinesis but no tracheal stenosis.

Female↗

PubMed1992

[Usefulness of a disposable nasogastric tube with a pH sensor--comparison with a class pH electrode].

We evaluated a disposable nasogastric tube with a pH sensor in comparison with an external glass pH electrode with aspiration of gastric contents, continuously. The mean pH value determined by pH sensor was 3.01, and 2.99 by glass pH electrode. There was a good correlation between the two methods (r = 0.91). The agreement between the two methods was especially good when pH less than 5.0. There was a wide scattering in the data when pH greater than 5.1. When the glass pH electrode data were above 5.1, the pH sensor tended to show lower pH values than glass pH electrode.

Electrodes↗

PubMed1992

[A case of pheochromocytoma in pregnancy].

A 29-year-old woman was referred to our hospital at the 34th week of her first pregnancy with a diagnosis of severe pregnancy-induced hypertension. A diagnosis of pheochromocytoma was made by elevated values of serum and urinary noradrenaline. Ultrasonography and computed tomography revealed a left adrenal tumor. Caesarean section combined with removal of the tumor at the 36th week of gestation was performed with a satisfactory result obtaining a healthy mother and an infant. Current management of patients with a pheochromocytoma during pregnancy is discussed.

Adrenal Gland Neoplasms↗

PubMed1992

A comparative study of once-a-day morning and once-a-day bedtime administration of 40 mg famotidine in treating gastric ulcers.

A randomized controlled study comparing once-a-day morning and once-a-day bedtime administration of 40 mg famotidine in treating gastric ulcers was carried out in 179 Japanese patients. Endoscopic examinations were performed at the baseline and repeated at 4-wk intervals until healing was confirmed. One hundred and sixty-four patients fulfilled the evaluation criteria (81 in the morning group and 83 in the bedtime group). The healing rates were 50.7% after 4 wk and 88.9% after 8 wk in the morning group and 46.5% after 4 wk and 74.7% after 8 wk in the bedtime group. The difference was statistically significant after 8 wk. Significant reductions from baseline for overall pain, beginning during the first 3 days, were likewise found in the two treatment groups. However, the pain severity in hunger state 1 wk after treatment was significantly higher in the bedtime group than in the morning group. Thus, once-a-day morning administration of 40 mg famotidine seems to be superior to once-a-day bedtime administration of 40 mg famotidine in treating gastric ulcers.

Adult↗

PubMed1992

An index of disease activity in patients with ulcerative colitis.

Quantification of disease severity was studied in 72 patients with ulcerative colitis, who had undergone total 85 clinical courses. We performed a multiple stepwise regression analysis, according to Truelove and Witts' classification, with disease severity as a dependent variable, and with 18 clinical, laboratory, and endoscopic parameters as independent variables. Results showed that disease severity in patients with ulcerative colitis is significantly influenced by five factors, namely, bloody stool, bowel movements, erythrocyte sedimentation rate (ESR), hemoglobin (Hb), and serum albumin. The activity index (AI) developed for ulcerative colitis is expressed as follows: AI = 60 x blood stool + 13 x bowel movements + 0.5 x ESR - 4 x HB - 15 x albumin + 200. Index values below 150, values between 150 and 220, and values above 220 nearly corresponded to mild, moderate, and severe disease, respectively, in Truelove and Witts' classification. We believe that the activity index is useful in evaluation of the effect of medical treatment in patients with ulcerative colitis. Its most important value will be in therapeutic trials.

Adolescent↗

PubMed1992

[Two cases of lateral approach for thoraco-lumbar junctional lesions: experiment of Kaneda's device].

Case 1: a 32-year-old woman was admitted to our hospital with major complaints of gait disturbance and urinary incontinence. The tendon reflex was markedly increased in the bilateral lower extremities, and both Babinski's reflex and clonus were strongly positive. Myelography revealed complete block in the 10th thoracic vertebral level. On April 15, 1989, a tumor in the vertebral region was exposed and excised via a right posterolateral approach. Kaneda's device was used for internal fixation. The tumor was diagnosed as myeloma histologically. The postoperative course was uneventful. Postoperatively, the patient became capable of walking by herself. Case 2: an 18-year-old woman was admitted because of burst fractures of the 1st and 2nd lumbar vertebrae due to a traffic accident in January of 1989. The fractured bones had been manually repositioned and fixed with plaster. However, the patient still had gait disturbance (intermittent claudication). Myelography revealed a complete block in the 2nd lumbar vertebral region. On May 7, the vertebral foramen was opened via a left anterolateral approach, and internal fixation was performed using Kaneda's device. Postoperatively, the patient recovered full ability to walk, and returned to normal social activity. From our experience, it is thought to be useful to employ a right posterolateral approach to the thoracic vertebrae, and a left anterolateral approach to the lumbar vertebrae. We used Kaneda's device for internal fixation, successfully. However, this device has the following disadvantages; (1) there are few plates designed for females, whose vertebrae are small, (2) it is difficult to preserve the arteries of Adamkiewicz and (3) postoperative MRI becomes impossible.

Adolescent↗

PubMed1991

CSK: a protein-tyrosine kinase involved in regulation of src family kinases.

The functions of src family protein-tyrosine kinases are thought to be regulated negatively by the phosphorylation of highly conserved tyrosine residues close to their carboxyl termini. Recently we have purified and cloned a protein-tyrosine kinase (designated as CSK) that can specifically phosphorylate the negative regulatory site of p60c-src. To elucidate the relationship between CSK and other types of src family kinases, we investigated the tissue distribution of CSK and examined whether CSK could phosphorylate the negative regulatory sites of src family kinases other than p60c-src. Western blot analysis indicated that CSK was enriched at the highest level in lymphoid tissues in which the expression of p60c-src is considerably lower than those of other types of src family kinases. CSK phosphorylated p56lyn and p59fyn, which are known to be expressed in lymphoid tissues at a relatively high level. The putative regulatory site, tyrosine 508, was found to be essential for phosphorylation in p56lyn, and the kinase activities of these src family kinases were repressed by phosphorylation with CSK. These findings raise the possibility that CSK might act as a universal regulator for src family kinases.

Amino Acid Sequence↗

PubMed1991

[Fracture of percutaneously inserted IVC filters--two cases of Günther's filter].

During the period from 1988 to 1990, percutaneous insertion of Günther vena caval filters were performed in ten patients in our institution. In two of them, fracture and partial migration of anchoring limbs were observed. Günthter's filter is an attractive device for interventional radiologist because of its technical ease of percutaneous placement and relative stability within the vein. However, our experience suggests that this device is not entirely safe and reliable. The patients should be carefully followed up with a possibility of distal migration in mind. Further structural improvement seems necessary.

Adult↗

PubMed1991

Cloning of a complementary DNA for a protein-tyrosine kinase that specifically phosphorylates a negative regulatory site of p60c-src.

The protein-tyrosine kinase activity of the proto-oncogene product p60c-src is negatively regulated by the phosphorylation of a tyrosine residue close to the C terminus, tyrosine 527. The phosphorylation might be catalysed by a so-far-unidentified tyrosine kinase, distinct from p60c-src. Recently we purified a protein-tyrosine kinase that specifically phosphorylates tyrosine 527 of p60c-src from neonatal rat brain. We have now confirmed the specificity of this enzyme by using a mutant p60c-src that has a phenylalanine instead of tyrosine 527, and cloned a complementary DNA that encodes the enzyme. The enzyme is similar to kinases of the src family in that it has two conserved regions, Src-homology regions 2 and 3, upstream of a tyrosine kinase domain. The amino-acid identity of each region is no more than 47%, however, and the enzyme lacks phosphorylation sites corresponding to tyrosines 416 and 527 of p60c-src and has no myristylation signal. These results suggest that this protein-tyrosine kinase, which might negatively regulate p60c-src, represents a new type of tyrosine kinase.

Amino Acid Sequence↗

PubMed1991

Identification of a ubiquitin- and ATP-dependent protein degradation pathway in rat cerebral cortex.

To investigate the existence of a ubiquitin-dependent protein degradation system in the brain, the proteolytic activity of the cerebral cortex was examined. The soluble extract of rat cerebral cortex degraded 125I-radiolabeled lysozyme in an ATP-dependent manner. The ATP-dependent proteolysis was suppressed with iodoacetamide, which inhibits ubiquitin conjugation, and was abolished by blocking of the amino residues of lysozyme. These results suggest the participation of ubiquitination in the proteolytic activity. An ATP-dependent 125I-ubiquitin-conjugating activity was detected in fraction II from the cerebral cortex. The presence of ATP-dependent proteolytic activity which acted preferentially on ubiquitinated lysozyme was demonstrated, using ubiquitin-125I-lysozyme conjugates as a substrate. The proteinase had a molecular mass of 1500 kDa and displayed nucleotide dependence and sensitivity to various proteinase inhibitors similar to those of the 26S proteinase complex found in reticulocytes. Dialysis of the soluble fraction caused a decrease in the proteolytic activity of ATP-dependent and preferential for ubiquitin-lysozyme conjugates and a reciprocal increase in the ATP-independent free 125I-lysozyme-degrading activity which was scarcely detected before dialysis. The former ATP-dependent proteolytic activity may play a physiological role in the brain.

Adenosine Triphosphate↗

PubMed1991

2.5S nerve growth factor enhances survival, phagocytosis, and superoxide production of murine neutrophils.

The effect of 2.5S nerve growth factor (NGF) on survival, phagocytosis, and superoxide production of murine neutrophils was examined and compared with the effects of interleukin-3 (IL-3) and recombinant GM colony-stimulating factor (rGM-CSF). NGF enhanced the viability of neutrophils isolated from peripheral blood and peritoneal cavity in a dose-dependent way. IL-3 50 U/mL had no effect. rGM-CSF 50 U/mL had an effect similar to that of 50 ng/mL NGF. NGF also enhanced the phagocytosis of hydrophilic microspheres by peritoneal neutrophils, and the activity of NGF was greater than that of IL-3 or rGM-CSF. NGF enhanced the superoxide production induced by phorbol 12-myristate 13-acetate (PMA), which acts at postreceptor sites, and that induced by opsonized zymosan, a receptor-mediated ligand. The stimulating activity of NGF was largely comparable to that of rGM-CSF. The present data show that NGF bound to neutrophils enhances their survival, phagocytosis, and superoxide production. Thus, we postulate that NGF plays an important role in the inflammatory processes.

Animals↗