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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 649 records · Page 36Linked to original sources

Acute hypoxic pulmonary vascular response does not accompany plasma endothelin-1 elevation in subjects susceptible to high altitude pulmonary edema.

We have previously shown that high altitude pulmonary edema-susceptible subjects (HAPE-S) have an accentuated pulmonary vascular response to hypoxia. In this study, we investigated the relationship between plasma endothelin-1 (ET-1) levels and the acute hypoxic pulmonary vascular response in HAPE-S and control subjects. In six HAPE-S and seven healthy subjects, we evaluated acceleration time/right ventricular ejection time (AcT/RVET) using Doppler echocardiography, and measured plasma ET-1 levels by radioimmunoassay (RIA) before and after 5 minutes of breathing 10% oxygen. The HAPE-S showed a significantly increased pulmonary vascular response to hypoxia compared with healthy subjects. However, no statistically significant changes of plasma ET-1 levels were observed before and after hypoxia in both groups. We conclude that the increased pulmonary vascular response to acute hypoxia in HAPE-S may not be related to ET-1 release.

Acute Disease↗

Metabolic alkalosis and myoclonus from antacid ingestion.

A patient with a history of cerebrovascular disease, hypertension, and previous gastrectomy developed metabolic alkalosis and myoclonus. His medications included the anti-hypertensive agents nicardipine hydrochloride, delapril, prazosin; dihydroergotoxin and ticlopidine for cerebral infarction; estazolam for insomnia; azuren-L-glutamine compound and S-M powder. In addition, he had taken 12 grams per day of Ohta's Isan antacid, which contained 625 mg sodium bicarbonate per 1.3 g of antacid powder over a 6-month period. This antacid is commonly used in Japan. This is the first report of a case of metabolic alkalosis and myoclonus secondary to ingestion of a commercially available antacid in Japan.

Aged↗

Chronic Prototheca meningitis.

A case of chronic meningitis caused by the achloric alga Prototheca wickerhamii is described, which has persisted for more than 6 years despite treatment with various antifungal agents. For the last year no treatment has been given, but the patient has no complaints.

Adult↗

Immunoreactivity to neurohormonal polypeptide in colorectal carcinomas and tumor-neighboring mucosa, and its significance.

OBJECTIVE: To clarify whether advanced colorectal carcinomas possess an amphocrine nature and produce both pancreatic and gut neurohormonal polypeptide and epithelial mucin in comparison with surrounding colorectal mucosa. DESIGN: Retrospective analysis of paraffin-embedded specimens from 100 cases of colorectal carcinoma (39 colonic and 61 rectal) and surrounding mucosa, with histochemical and immunohistochemical studies. RESULTS: The immunoreactivity of the carcinomas and surrounding mucosa by the labeled streptavidin-biotin complex method for polyclonal rabbit antibody against human vasoactive intestinal polypeptide, pancreatic polypeptide, and somatostatin was 61%, 59%, and 82% respectively; that of mucosa neighboring immunoreactive tumors was 87%, 85%, and 90%; and that of mucosa neighboring nonimmunoreactive tumors was 67%, 63% and 61%. Double staining for different types of neurohormonal polypeptide revealed that most carcinoma cells had a multiendocrine nature, and a number of neurohormonal polypeptide--positive and epithelial mucin-positive carcinoma cells (amphocrine cells) were found in almost every histological type of carcinoma by double staining for immunoreactivity and periodic acid-Schiff reaction or mucicarmin. CONCLUSION: Colorectal carcinomas exhibit not only multiendocrine characteristics, producing various types of neurohormonal polypeptide, but also amphocrine characteristics of different grades, and most tumor-neighboring crypt cells possess those characteristics, too. We concluded that these characteristics of colorectal carcinomas may be related to their origin as multipotential endodermal stem cells.

Adenocarcinoma↗

[Case of adult T-cell leukemia without antibodies for HTLV-I but with for pX gene region].

A 76-year-old woman had lymphocytosis with lymphocytes having convoluted or lobulated nuclei. These abnormal lymphocytes (leukemic cells) were positive for CD4, and some expressed IL-2R (CD25) and CD3 molecules, respectively. These morphologic and phenotypic features were compatible with adult T-cell leukemia, but serum antibodies to human T-cell lymphotropic virus type I (HTLV-I) were not detected by the particle aggregation method and an enzyme-linked immunosorbent assay. The polymerase chain reaction showed that the LTR, gag, pol, and env regions of HTLV-I proviral DNA had not been incorporated into the leukemic cells. Only the pX region was detected in these leukemic cells.

Aged↗

[Intracavitary bacillus Calmette-Guerin therapy for upper tract transitional cell carcinoma].

Four patients with upper urinary tract transitional cell carcinoma were treated with bacillus Calmette-Guerin (BCG) via a percutaneous nephrostomy tube or a retrograde ureteral catheter. A 68-year-old female and an 80-year-old male had carcinoma in situ (CIS) in the left upper urinary tract (cases 1 and 2). A man aged 47 had CIS in the left upper urinary tract, bladder, and prostatic urethra (case 3). CIS in the left upper urinary tract was identified in a woman aged 63 with chronic renal insufficiency (case 4). Two patients (cases 1 and 2) responded to this therapy. In the other two patients nephrectomy was performed due to residual tumor. There were extensive tuberculous granulomas in the kidneys. In one resected kidney (case 4) carcinoma had invaded the renal parenchyma. The reviewed literature showed that BCG perfusion therapy was effective in 71% (27 of 38 renal units) for the upper urinary tract tumors and that there were 5 cases of severe complication, including sepsis in 2, high fever in 2, and ureteral stricture in 1. Based on the fact that the kidney receives a profuse blood supply and that the renal pelvis and ureter have a thin wall, careful management is mandatory to prevent severe adverse effects and insidious tumor progression.

Aged↗

Effect of long-term administration of finasteride (MK-906), an inhibitor of 5 alpha-reductase, in patients with benign prostatic hyperplasia.

We evaluated the effect of long-term administration of finasteride (MK-906), a potent inhibitor of 5 alpha-reductase in patients with benign prostatic hyperplasia (BPH). The effect of an increase in dose was also assessed. Finasteride was administered to 61 patients with BPH at the dose of 1 mg/day for 48 weeks. Thirty three of these patients subsequently received finasteride at the dose of 5 mg/day for further 24 weeks in an open extension study. Urinary symptoms, urinary flow rate, residual urinary volume, prostatic volume and serum concentrations of dihydrotestosterone and prostate-specific antigen were examined periodically during the treatment. The size of the prostate and total urinary symptom scores decreased progressively during the first 16 weeks of treatment. The patients who received finasteride had a significant increase in the maximal urinary flow rate and a significant decrease in residual urinary volume. After 72 weeks of treatment, finasteride at an increased dose of 5 mg did not provide additional benefit to patients, although the effects of the drug at a dose of 1 mg were well maintained. Treatment with finasteride was well tolerated at both doses. In conclusion, the treatment of BPH with 1 mg of finasteride per day for 48 weeks results in a significant increase in maximal urinary flow rate, and a decrease in prostatic volume, symptoms of obstruction and residual urinary volume, with minimal toxicity.

5-alpha Reductase Inhibitors↗

[Anticoagulant related hemorrhage and thromboembolism after valvular surgery].

We reviewed anticoagulant related hemorrhage (ACRH) and thromboembolism (TE) in 84 patients after valvular surgery. There were 45 females and 39 males with a mean age of 51.8 years (range 30.5-71.2 years), who underwent valvuloplasty in 14, bioprosthetic valve replacements in 17, mechanical valve replacements in 13. A mean period from the operation to the event were 2.7 years (range 0.01-12.3 years). There were 25 ACRH events after one valvuloplasty, 4 bioprosthetic valve replacements, 20 mechanical valve replacements. About half of them, the prothrombin time were less than 25%, which was considered the effect of warfarin is high, and 8% of them had infective endocarditis (IE) previously. There were 59 TE events after 13 valvuloplasties, 13 bioprosthetic valve replacements, 33 mechanical valve replacements. In the patients with atrial fibrillation, TE occurred irrespective of operative procedures. And in the patients with mechanical valve, severely impaired left ventricular function and past history of IE, thrombi of left ventricule were caused of TE. It was suggested that past history of IE was a risk factor ACRH and TE, and severely depressed left ventricular function and atrial fibrillation were for TE.

Adult↗

Bilateral choroidal osteomas associated with histiocytosis X.

A 15-year-old Japanese girl complained of decreased visual acuity in the left eye of 1-month duration. Histiocytosis X had been diagnosed when she was 2 years old based on examination of biopsies of skin and cervical lymph nodes and bone marrow aspirations. She had been in complete remission for 7 years. She exhibited the characteristic ophthalmoscopic, ultrasonographic, and radiologic features of bilateral choroidal osteomas.

Bone Marrow↗

[Efficacy of left atrial only procedure for the treatment of chronic atrial fibrillation associated with mitral valve disease].

We supposed that chronic atrial fibrillation originated as a result of discontinuity of the refractory period of the dilated left atrium in the mitral valvular disease. We then performed left atrial only procedures to treat the chronic atrial fibrillation (AF) associated with mitral valve disease. These procedures were the left atrial isolation and the modified left sided maze procedure, consisting of isolation of all pulmonary veins and cryoablation to the posterior wall of the left atrium, in addition to excision of the left atrial appendage. Twenty-eight patients underwent these procedures over the past thirty months. Patient ages and the duration of AF ranged from 37 to 71 years and from 0.5 to 26 years, with an average of 8.3 years, respectively. Chronic AF disappeared in twenty-four patients (86%) at discharge. Three patients with severe tricuspid insufficiency had sustained AF and one patient had atrial flutter postoperatively. Three patients showed sick sinus syndrome postoperatively and two of these required a DDD pacemaker. Severe tricuspid regurgitation (p < 0.020) was the factor in recurrence of AF. Left atrial only procedures were effective in the treatment of chronic AF associated with mitral valvular disease.

Adult↗

[Acute type A aortic dissection after replacement of descending thoracic aorta for type B aortic dissection].

Two cases of acute type A aortic dissection after replacement of descending thoracic aorta for type B dissection were reported. One case involved a 75-year-old male who had hypertension. The second case involved a 33-year-old female with a familial history of thoracic aneurysms. Both patients underwent simultaneous graft replacement of the ascending aorta and total aortic arch using selective perfusion to the brain. Both patients survived the operations, and the postoperative courses were satisfactory. Acute type A dissection after replacement of descending thoracic aorta for type B dissection is rare, and careful and long-term follow-up is needed for the patients.

Acute Disease↗

Efficacy of oxygenated University of Wisconsin solution containing endothelin-A receptor antagonist in twenty-four-hour heart preservation.

BACKGROUND: The University of Wisconsin solution has been proven to be effective for prolonged heart preservation. However, 24-hour heart preservation by simple cold immersion in University of Wisconsin solution has been disappointing. We have performed hypothermic low-pressure continuous coronary perfusion with oxygenated University of Wisconsin solution for experimental prolonged heart preservation. However, the high potassium concentration of University of Wisconsin solution combined with prolonged ischemia has detrimental effects on endothelial function, which increases coronary tone during preservation and after reperfusion. The severe vasoconstriction and tissue edema result in damage to the coronary microcirculation. The purpose of this study was to determine whether hypothermic low-pressure continuous coronary perfusion technique with oxygenated University of Wisconsin solution containing a selective endothelin-A receptor antagonist (FR139317) would increase the effectiveness of the perfusion technique and improve postischemic cardiac function, both minimizing tissue edema and suppressing vasoconstriction. METHODS AND RESULTS: Preischemic and postischemic cardiac function of isolated rabbit hearts was evaluated with a Langendorff apparatus. The hearts were divided into three groups (n = 7 each): group I (hypothermic low-pressure continuous coronary perfusion with University of Wisconsin solution), group II (hypothermic low-pressure continuous coronary perfusion with oxygenated University of Wisconsin solution), and group III (hypothermic low-pressure continuous coronary perfusion with oxygenated University of Wisconsin solution containing 10 mg/L of FR139317). Preservation was performed for 24 hours. The initial perfusion pressure for continuous coronary perfusion was set at 5 mm Hg. Measurement of percentage of tissue water content and ultrastructural examination of the myocardium was then performed. In groups I, II, and III, the perfusion pressures at the end of the 24-hour preservation period increased from 5 mm Hg to 12.2 +/- 2.5, 8.1 +/- 1.3, and 5.4 +/- 0.8 mm Hg (p < 0.05), respectively. Percent recovery rate of cardiac output was 56.6 +/- 2.8, 82.3 +/- 8.2, and 93.3 +/- 6.0 (p < 0.05), respectively. And percent recovery rate of coronary flow was 55.5 +/- 8.1, 80.0 +/- 8.0, and 94.3 +/- 9.4 (p < 0.05), respectively. A significant inverse correlation was found between continuous coronary perfusion pressure at the end of preservation and the recovery rate of cardiac output (r = 0.85, p < 0.05). Tissue water content was significantly higher in group I than in groups II and III. These effects were inhibited by oxygenation of the University of Wisconsin solution (group II) and by the addition of the selective endothelin-A receptor antagonist (FR139317) (group III). Damage to coronary circulation was reduced by oxygenation and the addition of endothelin-A receptor antagonist during prolonged heart preservation. CONCLUSIONS: We concluded that hypothermic low-pressure continuous coronary perfusion technique with oxygenated UW solution containing endothelin-A receptor antagonist (FR139317) maintained coronary circulation by suppressing tissue edema and vasoconstriction during preservation, which improved postischemic functional recovery.

Adenosine↗

[Pulmonary malignant fibrous histiocytoma presenting as hemothorax].

A 39-year-old woman, who suffered from a sudden episode of severe left-sided back pain, was admitted to our hospital because of hemothorax. Chest CT scans revealed a mass extending from the left hilum to the posterior thoracic wall. The mass occluded the left pulmonary artery at the left main bronchus. Examination of a frozen section of a specimen obtained during a thoracotomy showed a sarcomatous tumor. A left pneumonectomy was then performed. Microscopic examination of a specimen revealed that the tumor was composed of spindle cells with cellular atypia and mitosis forming fascicles and storiform arrays. Malignant fibrous histiocytoma (storiform-pleomorphic pattern) was diagnosed. Chemotherapy was carried out six times during the year after surgery. No recurrence of the tumor has been seen during 20 months of follow-up.

Adult↗

Effect of heat shock on the expression of urokinase-type plasminogen activator receptor in human umbilical vein endothelial cells.

We investigated the effect of heat shock on the fibrinolytic potential of human umbilical vein endothelial cells (HUVECs) in culture. When cultured at 43 degrees C, the mRNA for heat shock protein 70 (HSP70) was dramatically induced within 120 min with a maximal induction of more than 90-fold compared with that in HUVECs cultured at 37 degrees C. The level of urokinase-type plasminogen activator (u-PA) receptor (u-PAR) mRNA increased up to 2.2-fold in response to heat shock, which was associated with the increased u-PA binding and cell-surface u-PA activity determined by adding exogenous u-PA to acid-treated HUVECs. The increased u-PAR mRNA returned to normal level when HUVECs were further incubated at 37 degrees C for 180 min, and this decline was not affected in the presence of actinomycin D. Though the secreted antigens for tissue-type plasminogen activator (t-PA) and type 1 plasminogen activator inhibitor (PAI-1) in the conditioned medium (CM) of HUVECs were simultaneously increased at 43 degrees C during this period, the increase in the levels of t-PA (about 26.6-fold at 120 min) was greater than that of PAI-1 (1.8-fold at 120 min). The fibrinolytic activity of CM obtained from HUVECs at 43 degrees C was significantly enhanced up to 3-fold, indicating that heat shock induced hyperfibrinolytic states in HUVECs. The secretion of u-PA into CM was also enhanced by heat shock. These results suggested that human endothelial cells respond to hyperthermia by inducing HSP70 followed by hyperfibrinolytic states with the enhanced expression of u-PAR as well as that of t-PA and u-PA.

Base Sequence↗

[Role of noninvasive graphic diagnosis in acute type A aortic dissection and selection of the adjunct for cerebral protection].

We have evaluated the usefulness of graphic diagnostic modalities (transthoracic echocardiography [TTE], high speed CT, transesophageal echocardiography [TEE], surface echocardiography [SE]) in acute type A aortic dissection and selected the adjunct to protect cerebral damage during operation followed by pre and intraoperative diagnosis. 1) Angiopraphy was undergone in only 5 cases of 22 cases of acute type A dissection. Intimal flap of the ascending aorta was completely diagnosed by TTE and CT. It was sometimes difficult to show the location of the intimal tear by TTE and CT (diagnostic sensitivity 64%, specificity 88%). However, TEE and SE showed the location of intimal tear in all cases (sensitivity 100%, specificity 100%) and also clarified the dissection of the coronary arterial orifice. CT and SE were useful to detect dissection of the cervical branches. 2) The adjunct for cerebral protection was selected by the diagnosis of the distension of the dissection. Retrograde cerebral perfusion was used in the cases with intimal tear in the ascending aorta (10 cases) and selective cerebral perfusion was selected in cases of the distended dissection, in which dissection involved the arch aorta and replacement of aortic arch was required (12 cases). Cerebral perfusion time and operative mortality was 48 min and 10% in the former and 72 min and 17% in the latter, respectively. Operative mortality was not different in both groups.

Adult↗

Detection of hepatitis C virus core protein in the glomeruli of patients with membranous glomerulonephritis.

Two Japanese patients suffered from membranous glomerulonephritis associated with hepatitis C virus (HCV) infection. Renal histologic changes were characterized by granular deposits of IgG and C3 along the capillary wall and numerous subepithelial deposits in glomeruli. Hypocomplementemia was present in one patient, but both cryoglobulins and rheumatoid factors were absent. HCV RNA was detected in both their sera by RT-PCR, both free and in the form of circulating immune complexes. The HCV core protein was found in the glomeruli from both patients by indirect immunofluorescence. These results suggest that in some patients chronic HCV infection causes membranous glomerulonephritis through immune complex deposition involving HCV proteins.

Aged↗

Decreased DNA topoisomerase II alpha expression and cold-sensitive growth in a mouse mammary cancer cell line resistant to etoposide and doxorubicin.

A mouse mammary carcinoma FM3A cell line resistant to the DNA topoisomerase (topo) II-targeting agent, etoposide (VP-16), FM3A/VP-2B, had a markedly reduced growth rate at a low temperature (33 degrees C). The cells had the following properties: (a) FM3A/VP-2B, which had 24-fold higher resistance to VP-16 than its parental line, FM3A, was cross-resistant to doxorubicin, but not to a camptothecin derivative, CPT-11. (b) Cold-resistant revertants from FM3A/VP-2B, R-6 and R-11, remained 8- to 9-fold more resistant to VP-16 and 2- to 3-fold more resistant to doxorubicin. (c) FM3A/VP-2B had one-fourth the level of topo II activity and one-third of the topo II alpha content and mRNA of FM3A. R-6 and R-11, however, had levels similar to FM3A. (d) FM3A/VP-2B and FM3A had a 3-base deletion at position 4170 on one allele on the topo II alpha cDNA, but expression of the wild-type and the deletion allele was not appreciably changed in both cell lines. Decreased topo II alpha expression might have led to the acquisition of drug resistance to etoposide in FM3A/VP-2B, and appeared to be linked with the cold-sensitive growth. We also present a corrected mouse topo II alpha cDNA sequence.

Amino Acid Sequence↗