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Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 649 records · Page 36Linked to original sources
PubMed1993

Evidence for the involvement of epidermal growth factor in fertility decline in aging female mice.

A decline in fertility, defined as the number of implantation sites, was observed in mice as they aged; the decline started at 30 weeks of age and reached a nadir by 60 weeks when no implantation was detected. Epidermal growth factor (EGF) levels in the submandibular gland and plasma increased as the female mice aged, and sialoadenectomy (surgical removal of the submandibular glands) attenuated the rise in the plasma EGF level without affecting the overall health or survival of the animals. Uterine weight at 10-20 weeks of age was about 70 mg, and it significantly increased with age. This weight has increased more than 2-fold by 60 weeks. These changes closely followed the increase in the concentrations of EGF in the submandibular gland and the plasma. After sialoadenectomy, uterine weight decreased immediately and remained at about 50-60 mg throughout the experimental period. Interestingly, sialoadenectomized mice became pregnant at an older age than the controls. These findings suggest that elevated levels of EGF may have a physiological role in fertility decline in aging mice perhaps via uterine hypertrophy.

Aging↗
PubMed1993

MR angiography of renal cell carcinoma.

Seventeen patients with renal cell carcinoma were studied to evaluate the usefulness of gradient echo (fast low-angle shot), time-of-flight magnetic resonance (MR) angiography under breath-holding. By reconstruction of the data of consecutive coronal scans of the abdomen, in all 17 patients with renal cell carcinoma, MR angiography can delineate the abdominal aorta, inferior vena cava and renal arteries and veins simultaneously without any contrast materials. Our present study suggested that MR angiography is a useful imaging method for preoperatively assessing spacial vascular structures of the abdomen of patients with renal cell carcinoma.

Adult↗
PubMed1993

Apnoea and oximetric desaturation in patients receiving epidural morphine after gastrectomy: a comparison of intermittent bolus and patient controlled administration.

The number of apnoeic episodes and arterial oxygen desaturations were measured preoperatively and for sixty hours postoperatively in twenty ASA status 1-2 patients scheduled for elective gastrectomy. Monitoring included continuous pulse oximetry, respiratory inductive plethysmography and repeated arterial blood gas analysis. The number and magnitude of apnoeas and desaturation episodes were compared between two postoperative analgesic regimens of epidural morphine; intermittent bolus injection (Group B, n = 10), and patient controlled administration with continuous infusion (Group P, n = 10). Morphine dose, P(a)CO2 and mean SpO2 values were similar between the two groups. Although the number of central apnoeas with SpO2 < 90% was greater in Group B, other episodes of apnoea or desaturation were similarly seen preoperatively. In the postoperative period, central apnoeas with SpO2 < 90% were significantly increased in Group B, while no change was seen in Group P. Apnoeas with SpO2 < 80% were only seen in Group B. We conclude from these results that postoperative apnoeas and episodic desaturations are greatly influenced by the different modes of opioid administration.

Adult↗
PubMed1993

Long-term alpha 1 blockade does not reverse cardiac hypertrophy in spontaneously hypertensive rats.

Not all antihypertensive drugs induce regression of left ventricular (LV) hypertrophy in hypertension, although they may equally lower blood pressure. The effects of alpha 1-blockers on regression have been inconsistent. In this study, bunazosin, a selective alpha 1-blocker, (15 mg/kg/day in food) was given to male spontaneously hypertensive rats (SHR) from 15 to 35 weeks of age to evaluate its effects on cardiac hypertrophy, hemodynamics, and neurohumoral factors. Age- and sex-matched SHR served as controls. LV function and cardiac output were determined by a micromanometer and thermodilution, respectively. Bunazosin significantly decreased blood pressure in conscious rats (from 209 to 192 mmHg, p < 0.01) but did not reduce LV mass. Heart rate, LV end-diastolic pressure, dp/dtmax, and cardiac output were similar in the 2 groups. Plasma renin activity was unaltered but plasma norepinephrine levels were higher in the treated rats (p < 0.05). Thus, bunazosin produced a significant relative reduction of blood pressure but did not reverse LV hypertrophy in SHR. Inadequate afterload reduction (8%) due to severe hypertension (> 200 mmHg) may explain the absence of regression. The rise of plasma norepinephrine levels may also offset the beneficial effects of bunazosin.

Adrenergic alpha-Antagonists↗
PubMed1993

[Enkephalin-inactivating enzymes].

The inhibitory effects of opioid peptides such as [Met5]-enkephalin and [Met5]-enkephalin-Arg6 on the electrically-evoked contractions of guinea-pig ileum, mouse vas deferens and rat vas deferens were enhanced by aminopeptidase inhibitors such as amastatin and bestatin, a peptidyl dipeptidase A inhibitor like captopril, and endopeptidase-24.11 inhibitors such as phosphoramidon and thiorphan. The magnitude of the enhancement by each peptidase inhibitor depended on both the preparation and opioid peptide employed. Additionally, enkephalin had been shown to be almost exclusively hydrolyzed at least in the ileal and striatal guinea pig membrane preparation by 3 kinds of enzymes, amastatin-sensitive aminopeptidase(s), captopril-sensitive peptidyl dipeptidase A and phosphoramidon-sensitive endopeptidase-24.11, which were indicated to be located very close to opioid receptors.

Aminopeptidases↗
PubMed1993

A comparative study of urinary xanthopterin and neopterin in liver diseases.

By adsorption to activated charcoal, various pteridine derivatives in human urine are oxidized to xanthopterin. Following this oxidation, xanthopterin in urine from healthy subjects and from patients with liver diseases was assayed by high performance liquid chromatography. The mean values for xanthopterin in healthy subjects were 532 +/- 116 mumol/mol creatinine (mean +/- SD) in males and 585 +/- 153 mumol/mol creatinine in females; the difference was statistically significant (p < 0.01). Xanthopterin concentrations in patients with liver disease were significantly higher than those in normal subjects. When compared with urinary neopterin, which is a marker of activated cell immunity, xanthopterin was significantly increased even in fatty liver disease. These findings suggest that increased concentrations of urinary xanthopterin in liver diseases reflect not only the status of activated cell-mediated immunity, but also injury to liver cells.

Adult↗
PubMed1993

The uterine growth-promoting action of epidermal growth factor and its function in the fertility of mice.

Epidermal growth factor (EGF) levels in the submandibular glands and plasma are increased in pregnant and aged female mice. The possible role of EGF in fertility was studied in virgin and pregnant mice ranging in age from 10 to 90 weeks of age, employing sialoadenectomy, administration of EGF antibody and EGF replacement. The uterine weight in pregnant, 10-week-old, sialoadenectomized mice was significantly less than in normal mice and the administration of EGF antibody to these mice further decreased uterine weight, resulting in an increased rate of abortion. Replacement EGF treatment in the sialoadenectomized mice prevented these changes. Uterine weight was about 70 mg at 10 weeks of age, and significantly increased from 30 to 80 weeks when it reached a plateau level of 275 mg. These changes closely followed the increase in the concentration of EGF in the submandibular glands and plasma and coincided with the decline in fertility. In contrast, uterine weight in the sialoadenectomized mice decreased immediately after the operation and remained at about 50-60 mg throughout the experimental period. Pregnancy, as judged by implantation, was achieved in the sialoadenectomized mice at later ages than in the controls. These findings suggest that elevated EGF levels may have a dual function in the control of fertility via uterine growth, depending on the age of mice.

Aging↗
PubMed1993

Hemostasis of gastric variceal hemorrhage by transileocoecal and transhepatic obliteration.

Obliteration for gastric or duodenal variceal hemorrhage was performed via transileocoecal or transhepatic portal catheterization in 8 patients with portal hypertension. The patients were 6 men and 2 women, whose average age was 59 years. All of the patients had cirrhosis of the liver. The obliteration was performed as an emergency procedure in 6 cases, and 2 patients were electively treated. Transileocoecal obliteration (TIO) and transhepatic obliteration (PTO) were selected for 6, and 2 patients, respectively. Variceal bleeding was successfully controlled in all patients after completion of the therapy. One patient died after 3 months when duodenal variceal bleeding recurred. Elective surgical operations were performed on 2 patients after the initial therapy, because the vein feeding toward the varices remained. Six of the patients have survived to date without bleeding. Transient oliguria and jaundice after the therapy were noticed in 2 patients. Histological examination revealed cast formation of polymerized cyanoacrylate in the obliterated gastric varices of 2 patients. TIO and PTO seem to be safe, effective procedures to stop bleeding from ectopic varices, gastric or duodenal. This therapy is useful either to obtain accurate information about the varices or to obliterate the collateral veins in patients with ruptured ectopic varices.

Adult↗
PubMed1993

[An aspiration pneumonia in acute airway damage model induced by HCl and/or LPS].

The purpose of this study is to evaluate chemical and pathological changes of the lung and to elucidate the role of TNF alpha and elastase in acute lung injury induced by HCl or lipopolysaccharide (LPS). Anesthetized rats were injected with pH 1.4 0.7 ml/kg body weight of HCl and 0.5 mg/kg body weight (BW) of LPS (E. coli) into the lung. Acute tracheal injury model (Mendelson Syndrome) were made. Control animals received only saline. Animals were sacrificed 1, 6, or 12 hours after the HCl or LPS or HCl and LPS injection, bronchoalveolar-lavage (BAL) was performed in the same way in control and experimental groups. The other animals which were treated as well were excised by histology. There was neither increase in TNF alpha-production nor increase in neutrophils resulting from HCl injection only. Elastase-like activity was not detected in animals treated only with HCl. However, 1 hour after LPS injection, the production of TNF alpha (37.0 +/- 8.0 Units/ml) was significantly greater than that of the control group (12.1 +/- 4.2 Units/ml) in BALF. Six hours after HCl and LPS injection, the concentration of elastase-like activity (0.023 +/- 0.002 nM) was significantly greater than that of the LPS group (0.011 +/- 0.001 nM). Only patches of intraalveolar hemorrhage and elevation of fibrin was observed in the HCl injected rats at 1 hour after injection. Six hours after LPS injection, the alveolar spaces were filled with large amounts of neutrophils. These findings suggest that TNF alpha and elastase play a significant role in HCl and LPS-induced acute lung injury.

Acute Disease↗
PubMed1993

[The effect of perioperative portal venous inoculation with donor lymphocytes in combination with immunosuppressive agents on rat cardiac allograft survivals].

The synergistic effects of inoculation with donor lymphocytes via portal vein (PV) in combination with FK506 or monoclonal anti-T lymphocyte antibody (OX19) on cardiac allograft survival were investigated in rat heart transplant model (Lewis engrafted BN heart). The recipients were divided into the six groups. A) Control B) FK506 group C) PV group D) FK506+PV group E) OX19 group F) OX19+PV group. The recipients of PV group and FK506 group displayed a prolongation of cardiac allograft survival [MST: 11.2 +/- 1.0 and 12.4 +/- 1.0 days] compared with control group [MST: 7.3 +/- 0.3 days]. However, MST of FK506+PV group was 10.6 +/- 0.8 days, showing no synergistic effect of FK506 with PV administration. Significant prolongation of the graft survivals was not observed between OX19 group and OX19+PV group [MST: 17.2 +/- 2.1 and 15.0 +/- 1.2 days]. Serum from PV-treated hosts on day 7 after transplantation had suppressor effect (92.7%) on the MLR of Lewis responder cells toward donor BN cells. On the other hand, suppressor effect of serum from FK506+PV group was significantly reduced (5.8%) compared with PV alone. These results indicate that FK506 might inhibit the generation of suppressor factor which was induced in the serum after administration of donor lymphocytes, and that generation of suppressor factor might be dependent on T cell.

Animals↗
PubMed1993

The biosynthesis of a cytotoxic protein, alpha-sarcin, in a mold Aspergillus giganteus. I. Synthesis of prepro- and pro-alpha-sarcin in vitro.

The biosynthesis of alpha-sarcin, a ribosome inactivating protein (16.9 KDa) was studied in a mold Aspergillus giganteus. The fungus begins to secrete alpha-sarcin after reaching a stationary phase around 50 h of culture. The synthesis of alpha-sarcin was shown to be induced at the transcriptional level since the mRNA level of alpha-sarcin, titrated by immuno-precipitation with anti-alpha-sarcin antibodies of translation products in wheat germ cell-free system, was increased synchroniously with the production of the protein. The immuno-precipitates specific for alpha-sarcin contained two species of proteins of 22.5 and 18.5 KDa. The former was localized in the supernatant and the latter was segregated in the microsomes of the wheat germ system. The 22.5 KDa protein was thought to be the primary product of alpha-sarcin, although N-terminal methionine was removed, because it was the only product when the microsomes were solubilized by Triton X-100 prior to translation in the cell-free system. These results indicate that alpha-sarcin is synthesized as 22.5 KDa prepro-alpha-sarcin and is processed cotranslationary into 18.5 KDa pro-alpha-sarcin in endoplasmic reticulum as usual secretary proteins.

Aspergillus↗
PubMed1993

Production of dihydrofolate reductase by an improved continuous flow cell-free translation system using wheat germ extract.

We have examined the characteristics of protein synthesis in an improved continuous flow cell-free translation system prepared from wheat germ extract with dihydrofolate reductase mRNA as the translated message. Continuous buffer flow and separation of the product from the reaction mixture were accomplished by the use of a modified Amicon ultrafiltration chamber as the reaction vessel. The system worked for 19 hours and produced 1.52 nmol (27.4 micrograms) of enzymatically active dihydrofolate reductase.

Base Sequence↗
PubMed1993

The biosynthesis of a cytotoxic protein, alpha-sarcin, in a mold of Aspergillus giganteus. II. Maturation of precursor form of alpha-sarcin in vivo.

Since Aspergillus giganteus ribosomes are sensitive to their own product, alpha-sarcin, we studied how resistance of protein synthesizing machinery is conferred in the cells. Immunoblotting analysis of a cell-extract prepared from mycelia of alpha-sarcin-producing phase showed two anti-alpha-sarcin reactive proteins which have molecular weights of 18.5 KDa and 16.9 KDa. The former and the latter were identified as the precursor and the mature forms of alpha-sarcin, respectively. Electronmicroscopic observation examining the location in situ by labeling with protein A-gold suggested that alpha-sarcin-related proteins are exclusively localized in large and small vacuoles. The small vacuoles, distributed near cell wall, appear to be involved in maturation and in the secretion of the protein. The present results suggested that alpha-sarcin is synthesized in an inactive precursor form and segregated in the membrane compartment through the synthesis and the maturation of alpha-sarcin in the cells.

Aspergillus↗
PubMed1993

[Clinical studies on the need of prophylactic antibiotics during extracorporeal shock wave lithotripsy].

We examined whether prophylactic antibiotics are necessary or not during the ESWL treatment for patients with urolithiasis. Twenty-eight patients with unilateral renal or ureteral stones composed of calcium oxalate, calcium phosphate or the mixed stones were treated with MPL 9000 between May 12 and September 30, 1992. Although 17 patients (60.7%) had complications of pyuria before treatment, none of the 28 patients had taken any prophylactic antibiotics during the treatment. To evaluate the clinical signs of infection, we examined the white blood cell count, in blood and urine sediment and serum C-reactive protein (CRP) value at the time of 1, 3 and 7 days after ESWL treatment, and body temperature and urine culture at the time immediately after the treatment in addition to the above-mentioned days, compared with the pre-treatment data. White blood cell count at one day after ESWL treatment was significantly elevated both in the patients with and without pyuria, while body temperature at the time immediately after the treatment was significantly elevated only in the patients with pyuria. Six of the 23 patients (26.1%) with preoperative sterile urine and who had urine culture immediately after ESWL, had bacteriuria. However, none of the 28 patients had any clinically significant infectious complications during ESWL treatment without any antibiotics therapy. We concluded that it is important to examine urine culture immediately after ESWL treatment for early protection from complication of urinary tract infection and that administration of prophylactic antibiotics is not necessary during ESWL treatment for patients with non-infection stones even concomitantly with pyuria.

Adult↗
PubMed1993

Pulmonary carcinoma associated with hamartoma in an 11-year-old boy.

PURPOSE: We describe a poorly differentiated adenocarcinoma of the lung in an 11-year-old boy who had had a pulmonary hamartoma for at least 8 years. CONCLUSIONS: A hamartoma, even if clinically silent, may lead to the development of malignant tumors on rare occasions.

Adenocarcinoma↗
PubMed1993

[A case of papillary fibroelastoma of the heart found 13 years after open mitral commissurotomy].

A patient, 68-year-old female, underwent open mitral commissurotomy (OMC) for rheumatic mitral stenosis in April, 1979. In July of 1992, during the postoperative follow-up echocardiogram showed 8 x 7 mm mitral subvalvular tumor mass and mitral restenosis. Then, mitral valve replacement was performed using prosthetic valve (Carbomedics #25 mm). The tumor was located on the top of postero-medial papillary muscle and its chordae, and histologically was diagnosed as benign papillary fibroelastoma. Based on the findings of periodic echocardiogram, the tumor doubling time was estimated to be 283 days. The postoperative course was uncomplicated and she was discharged on the 34th post operative day. Papillary fibroelastoma is a rare benign cardiac tumor. Pathological origin of this tumor is still unknown. However, Lambl's excrescence, long-term inflammatory stimulation and/or thrombi are supposed to be etiologic factors. This tumor is generally found incidentally at the time of autopsy or operation because the patients are often asymptomatic. However, because the tumor causes embolism at times, periodic examination by echocardiogram after operation preserving valves is recommended, and surgical resection is required when the diagnosis is established.

Aged↗
PubMed1993

[Clinical characteristics and treatment results of acute promyelocytic leukemia in children (Children's Cancer and Leukemia Study Group)].

The clinical characteristics and treatment outcome in 40 children with acute promyelocytic leukemia (APL) treated at institutions participating in the Children's Cancer and Leukemia Study Group (CCLSG) were studied retrospectively. The median age at diagnosis was 8 years old. Bleeding diathesis was the predominant presenting symptom (90%), associated with laboratory findings of disseminated intravascular coagulation. Hepatomegaly, splenomegaly and lymphadenopathy were observed in 35%, 10%, and 15% of the cases, respectively. The median WBC count was 4.25 x 10(9)/l. Anemia (hemoglobin < 8 g/dl) and thrombocytopenia (< 30 x 10(9)/l) were present in more than half of the patients. Cytogenetic studies demonstrated the characteristic 15; 17 translocation in about 90% of the patients analyzed. Induction therapy consisted of cytosine arabinoside and an anthracycline, with or without other agents. Twenty-nine patients (73%) achieved complete remission (CR) while early fatal hemorrhage was the predominant cause of induction failure. The survival rates continued to decrease (28% at 3 years, 24% at 5 years, and 7.9% at 10 years) due to late marrow relapses. Anthracycline cardiotoxicity was fatal in three patients in remission. These clinical features of childhood APL should be taken into account in the development of new protocols.

Adolescent↗