Biomedical subjects

T Oka

Publications and source records attributed to T Oka.

At least 217 records · Page 12Linked to original sources

PubMed1999

Histopathological prognostic factors influencing long-term prognosis after surgical resection for hepatic metastases from colorectal cancer.

OBJECTIVE: We aimed to present new histopathological features of metastatic liver nodules as more reliable prognostic factors after surgical resection for colorectal metastatic cancer. METHODS: Clinicopathological features, including newly proposed histopathological ones, of 63 consecutive patients were reviewed retrospectively to determine which most strongly correlated with long-term prognosis after hepatectomy for metastatic tumors from colorectal cancers, using univariate and multivariate analysis. RESULTS: The 1-, 3-, and 5-year cancer-related survival rates after hepatectomy were 87.8%, 55.2%, and 47.3%, respectively. New histopathological features we proposed, which are expansive growth, marginal fibrosis, and peritumorous lymphocytic infiltration of hepatic tumor, were significant prognostic factors for cancer-related survival after hepatectomy in an univariate analysis. Also in a multivariate analysis, i.e., a stepwise Cox regression analysis, infiltrative, i.e., not expansive, growth of hepatic tumor was one of significant and independent poor prognostic factors for survival after hepatectomy, with moderate to severe lymphatic vessel involvement of the primary colorectal lesion, microscopic cancer invasion at the surgical margin of hepatectomy, and extrahepatic distant metastases. CONCLUSIONS: Our results suggest that our proposed new histopathological features of hepatic metastases were good predictors of prognosis after surgical resection for hepatic metastases from colorectal cancer. Especially, infiltrative growth of hepatic tumor is strongly correlated with a poor prognosis after hepatectomy.

Colorectal Neoplasms↗

PubMed1999

[Efficacy of influenza vaccine among geriatric inpatients: effect of previous vaccination and antibody induction by single and twice injections].

To investigate the effect of previous influenza vaccination and the difference in antibody induction by single and twice injection of influenza vaccine in the elderly, hemagglutination inhibition (HI) antibody titers of the three types of influenza viruses were measured. Influenza vaccination was done for 217 inpatients. For the patients who had influenza vaccination in the year prior to the study, influenza vaccine was administered once to 77 patients and twice to another 70 patients. Influenza vaccine was injected twice to 70 patients who had not received influenza vaccine in the previous years. The influenza vaccine induced an increase in HI titer in almost all patients. The geometric mean of the HI titer and the frequency of patients with HI titers over 128x were similar after vaccination in the groups of patients who were injected twice, irrespective of whether or not influenza vaccination was given in the year prior to the study. The geometric means of the HI titers for influenzas A/H3N2 and B and the frequency of HI titers over 128x for influenza A/H3N2 after vaccination were lower in the patients who received vaccine once than in the patients vaccinated twice. These results suggest that prior vaccination does not diminish antibody response to influenza vaccine significantly in the elderly when influenza vaccine is injected twice. Although single injection is inferior to twice injection in antibody induction with some vaccine virus strains, induction of HI titers over 128x is found in more than 70% of elderly. Single injection of influenza vaccine may be practically effective and useful for protection of influenza infection in the elderly.

Aged↗

PubMed1999

Bone morphogenetic proteins induce cardiomyocyte differentiation through the mitogen-activated protein kinase kinase kinase TAK1 and cardiac transcription factors Csx/Nkx-2.5 and GATA-4.

Bone morphogenetic proteins (BMPs) have been shown to induce ectopic expression of cardiac transcription factors and beating cardiomyocytes in nonprecardiac mesodermal cells in chicks, suggesting that BMPs are inductive signaling molecules that participate in the development of the heart. However, the precise molecular mechanisms by which BMPs regulate cardiac development are largely unknown. In the present study, we examined the molecular mechanisms by which BMPs induce cardiac differentiation by using the P19CL6 in vitro cardiomyocyte differentiation system, a clonal derivative of P19 embryonic teratocarcinoma cells. We established a permanent P19CL6 cell line, P19CL6noggin, which constitutively overexpresses the BMP antagonist noggin. Although almost all parental P19CL6 cells differentiate into beating cardiomyocytes when treated with 1% dimethyl sulfoxide, P19CL6noggin cells did not differentiate into beating cardiomyocytes nor did they express cardiac transcription factors or contractile protein genes. The failure of differentiation was rescued by overexpression of BMP-2 or addition of BMP protein to the culture media, indicating that BMPs were indispensable for cardiomyocyte differentiation in this system. Overexpression of TAK1, a member of the mitogen-activated protein kinase kinase kinase superfamily which transduces BMP signaling, restored the ability of P19CL6noggin cells to differentiate into cardiomyocytes and concomitantly express cardiac genes, whereas overexpression of the dominant negative form of TAK1 in parental P19CL6 cells inhibited cardiomyocyte differentiation. Overexpression of both cardiac transcription factors Csx/Nkx-2.5 and GATA-4 but not of Csx/Nkx-2.5 or GATA-4 alone also induced differentiation of P19CL6noggin cells into cardiomyocytes. These results suggest that TAK1, Csx/Nkx-2.5, and GATA-4 play a pivotal role in the cardiogenic BMP signaling pathway.

Bone Morphogenetic Proteins↗

PubMed1999

Determination of granulocyte-specific antigens on neutrophil FcA receptor IIIb by PCR-preferential homoduplex formation assay, and gene frequencies in the Japanese population.

BACKGROUND AND OBJECTIVES: Granulocyte-specific antigens play an important role in provoking immune neutropenia and transfusion reactions. We developed a new DNA-typing method, PCR-preferential homoduplex formation assay (PHFA), to determine granulocyte-specific antigens on the neutrophil Fcgamma receptor IIIb (FcgammaRIIIb, CD16b), namely, the NA1, NA2, and SH antigens and their gene frequencies in the Japanese population. MATERIALS AND METHODS: Four hundred unrelated healthy Japanese blood donors were typed using PCR-PHFA. To confirm the accuracy of the results of FcgammaRIIIB genotyping using PCR-PHFA, PCR-sequence-specific primer (SSP) typing and PCR-restriction fragment length polymorphism (RFLP) typing were carried out in another 20 samples for comparison. RESULTS: The results of PCR-PHFA typing agreed well with other methods. The frequencies of the FcgammaRIIIB alleles were 62.2, 37.8, 0 and 0% for NA1, NA2, SH, and 'NA-null', respectively. CONCLUSION: The PCR-PHFA method can be semi-automated easily with computer-based assignment and is suitable for typing both small and large numbers of samples. In the Japanese population, the frequency of NA1 is about double that in Caucasians (32.5%), and the SH allele is rare.

Alleles↗

PubMed1999

Hormonal induction of mouse selenocysteine transfer ribonucleic acid (tRNA) gene transcription-activating factor and its functional importance in the selenocysteine tRNA gene transcription in mouse mammary gland.

Mouse selenocysteine transfer RNA (tRNA) gene transcription-activating factor (mStaf) is a transcriptional activator that enhances RNA polymerase III-dependent mouse selenocysteine tRNA (tRNA(Sec)) gene transcription. The DNA-binding activity of mStaf in mouse mammary gland undergoes developmental changes, reaching a maximal level during the period of lactation. In this study, we employed an organ culture system to examine the hormonal regulation of mStaf binding and its role in the tRNA(Sec) transcription in the mammary gland. The results showed that mStaf binding in mammary explants was stimulated by treatment with the lactogenic hormones, PRL, insulin, and hydrocortisone and that a specific MEK inhibitor, PD98059, inhibited the hormonal stimulation of mStaf binding. Other kinase inhibitors, such as a Janus kinase inhibitor and a calmodulin kinase inhibitor, had no apparent effect. Northern and Western blot analyses revealed that the level of both mStaf messenger RNA and protein was enhanced by the lactogenic hormones and was reduced by the concomitant treatment with PD98059. The mitogen-activated protein kinase activity in cultured explants was rapidly induced and maintained at high levels by the lactogenic hormones. We also found that the lactogenic hormones increased the amount of tRNA(Sec) in a time-dependent manner, which followed the increase in mStaf binding in cultured mammary explants. These results support the view that mStaf plays a key role in the hormonal stimulation of tRNA(Sec) transcription in the mammary gland.

Animals↗

PubMed1999

Oral administration of sepimostat mesilate prevents acute alcohol pancreatic injury in rats.

The preventive effect of a novel synthetic serine protease inhibitor, sepimostat mesilate (sepimostat), on acute alcohol pancreatic injury, induced by exocrine hyperstimulation and ethanol administration, was assessed and compared with that of a similar protease inhibitor, camostat mesilate (camostat). Conscious rats were infused with 1 microg mL(-1) h(-1) caerulein intravenously for 6 h and with 0.1 g mL(-1) h(-1) ethanol for 9 h, with the latter infusion beginning 3 h after the start of the caerulein infusion. Sepimostat or camostat was administered orally 1 h before the caerulein infusion. Rats infused with caerulein plus ethanol showed increased plasma amylase and lipase activities, and aggravated pancreatic interstitial oedema when compared with rats given caerulein alone. Sepimostat at 10 and 30 mg kg(-1) prevented the increase in plasma amylase and lipase activities caused by caerulein plus ethanol infusion. Sepimostat at 30 mg kg(-1) suppressed the histological change. Camostat did not show any preventive effects at the equivalent dose. When conscious rats were infused with 1 microg mL(-1) h(-1) caerulein alone intravenously for 6 h, plasma amylase and lipase activities were increased compared with rats given saline. Neither drug prevented the increase in these activities at 30mg kg(-1). Our results suggest that sepimostat has superior preventive effects on alcohol-induced acute pancreatic injury compared with camostat. Sepimostat may thus be a useful drug in the therapy of alcohol-induced pancreatitis.

Acute Disease↗

PubMed1999

Morphologic correlation between atherosclerotic lesions of the carotid and coronary arteries in patients with angina pectoris.

The morphology of atherosclerosis between the carotid and coronary artery systems was studied in 63 patients with ischemic heart disease to determine if there was a correlation with coronary heart disease. The sclerotic lesions of the carotid and coronary artery systems were imaged with ultrasonography and coronary arteriography, respectively, and divided into 4 types. Hemodynamic variables, serum lipid levels, and serum uric acid concentration were not different among the groups, but the serum C-reactive protein (CRP) concentration in patients without significant atheroma in the carotid artery system was lower than the mean concentration of the other 3 groups with carotid atheroma. The morphological stability of carotid arterial plaques correlated well to coronary artery stenosis. Morphologically unstable plaques of the carotid artery predicted unstable forms of coronary obstruction with a sensitivity of 68%, specificity of 85%, predictive power of 72% and a likelihood ratio of 4.5. These results suggest that ultrasonic examination of the carotid artery is useful for predicting the presence or absence of unstable lesions in coronary arteries.

Aged↗

PubMed1999

Time course of changes in mu-opioid receptor mRNA levels in the periaqueductal gray of rat brain by a single or repeated injections of antisense oligodeoxynucleotides.

The effect of phosphorothioated antisense oligodeoxynucleotide (AS ODN) against the mu-opioid receptor (MOR) on MOR mRNA level in the periaqueductal gray (PAG) of rat brain was investigated. The MOR mRNA levels at 3, 6, 12, 24, 48 and 72 h after MOR AS ODN microinjection into the PAG were determined by reverse transcriptase-polymerase chain reaction. The MOR mRNA level was significantly decreased only at 12 h after the injection of 10 microg MOR AS ODN. When 10 microg MOR AS ODN was given three times at the interval of 48 h, MOR mRNA levels were significantly decreased at 6, 12 and 24 h after the last injection of the AS ODN. However, MOR mRNA levels were not significantly changed by three injections at 48-h interval of MOR sense ODN or AS ODNs against delta- and kappa-opioid receptors, although the two latter AS ODNs significantly reduced the respective targeted mRNA levels. In conclusion, the present results show that the selective decrease in MOR mRNA is at least one reason why the reported diminished effects of MOR agonists are produced in animals pretreated with MOR AS ODN, although they could be produced through several mechanisms in which MOR mRNA level does not change.

Animals↗

PubMed1999

DS86 neutron dose: Monte Carlo analysis for depth profile of 152Eu activity in a large stone sample.

The depth profile of 152Eu activity induced in a large granite stone pillar by Hiroshima atomic bomb neutrons was calculated by a Monte Carlo N-Particle Transport Code (MCNP). The pillar was on the Motoyasu Bridge, located at a distance of 132 m (WSW) from the hypocenter. It was a square column with a horizontal sectional size of 82.5 cm x 82.5 cm and height of 179 cm. Twenty-one cells from the north to south surface at the central height of the column were specified for the calculation and 152Eu activities for each cell were calculated. The incident neutron spectrum was assumed to be the angular fluence data of the Dosimetry System 1986 (DS86). The angular dependence of the spectrum was taken into account by dividing the whole solid angle into twenty-six directions. The calculated depth profile of specific activity did not agree with the measured profile. A discrepancy was found in the absolute values at each depth with a mean multiplication factor of 0.58 and also in the shape of the relative profile. The results indicated that a reassessment of the neutron energy spectrum in DS86 is required for correct dose estimation.

Construction Materials↗

PubMed1999

A crack model of the Hiroshima atomic bomb: explanation of the contradiction of "Dosimetry system 1986".

There has been a large discrepancy between the Dosimetry system 1986 (DS86) and measured data, some of which data in Hiroshima at about 1.5 km ground distance from the hypocenter are about 10 times larger than the calculation. Therefore its causes have long been discussed, since it will change the estimated radiation risks obtained based on the Hiroshima and Nagasaki data. In this study the contradiction was explained by a bare-fission-neutron leakage model through a crack formed at the time of neutron emission. According to the present calculation, the crack has a 3 cm parallel spacing, which is symmetric with respect to the polar axis from the hypocenter to the epicenter of the atomic bomb. We made also an asymmetric opening closing 3/4 of this symmetric geometry, because there are some data which shows asymmetry. In addition, the height of the neutron emission point was elevated 90 m. By using the asymmetric calculation, especially for long distant data located more than 1 km, it was verified that all of the activity data induced by thermal and fast neutrons, were simultaneously explained within the data scattering. The neutron kerma at a typical 1.5 km ground distance increases 3 and 8 times more than DS86 based on the symmetric and asymmetric model, respectively.

Humans↗

PubMed1999

Involvement of gonadal steroid hormone disturbance in altered prolactin receptor gene expression in the liver of diabetic mice.

The levels of mRNA for long and three short forms of prolactin receptor (PRLR) were examined in the livers of normal (db+/db-) and insulin-resistant diabetic (db+/db+) mice to assess the role of gonadal steroid hormones in the regulation of PRLR gene expression in diabetes mellitus. In females, plasma levels of testosterone in diabetic mice were higher, and those of 17beta-estradiol were lower when compared with levels in normal mice. By contrast, diabetic male mice had lower plasma levels of testosterone than normal males and showed no significant difference in the low circulating level of 17beta-estradiol compared with normal males. The short 3 form of PRLR (PRLR3) mRNA was the most abundant in the liver of both normal and diabetic mice. In addition, the level of PRLR3 mRNA in normal females was 8-fold higher than in normal males. The level of PRLR3 mRNA in diabetic females was approximately a quarter lower than in normal females, whereas the level of PRLR3 mRNA in diabetic males was approximately 2-fold higher than in normal males. During postnatal development, the level of PRLR3 mRNA increased during puberty in normal females, while the level in diabetic females decreased to a nadir at 7 weeks of age followed by a progressive rise. On the other hand, the levels of PRLR3 mRNA in both normal and diabetic males decreased gradually during 5 to 14 weeks of age. Testosterone treatment of diabetic males and females resulted in a 49.1 and 49.8% decrease of PRLR3 mRNA respectively. 17beta-Estradiol treatment slightly (18%) increased levels of PRLR3 mRNA in diabetic males. These results suggest that the hepatic level of PRLR mRNA is regulated by the inhibitory effect of testosterone and the stimulatory effect of estrogen in both normal and diabetic mice.

Animals↗

PubMed1999

Two cases of aorto-gastrointestinal fistula.

We report two cases of aorto-gastrointestinal fistula. Case 1, a 60-year-old man, suffered from repeat hematemesis. He was preoperatively diagnosed as aortoesophageal fistula with thoracic aortic aneurysm and was successfully treated by graft replacement of the aneurysm. Case 2, a 73-year-old man, presented with massive gastrointestinal bleeding, yet repeat endoscopical examination did not reveal the origin of the bleeding. He died of catastrophic hematochezia. The pathological findings at autopsy revealed an aortoduodenal fistula. These two cases suggested the importance to consider an aorto-gastrointestinal fistula in the differential diagnosis of patients presenting gastrointestinal hemorrhage.

Aged↗

PubMed1999

Rapid and simple analysis of urinary vanilmandelic acid by high-performance liquid chromatography with electrochemical detection.

We examined an analytical method for urinary vanilmandelic acid (VMA) by high-performance liquid chromatography with electrochemical detection from the viewpoint of practical analysis and application. The sample pretreatment in our method is only the dilution of urine samples with citrate buffer. The calibration curve for VMA was linear within the range 0.2 to 20 ng. The detection limit was 50 pg at a signal-to-noise ratio of 3 and the coefficients of variation were 2.30-4.30%. Variations in the urinary levels of VMA, noradrenaline (NA) and adrenaline (Ad) during and after exercise were investigated for 5 males (mean +/- SD, 42.4 +/- 4.3 years of age). The high levels of urinary NA and Ad during 1 hr exercise rapidly decreased after exercise, whereas urinary VMA increased after exercise rather than during exercise and decreased later. The correlation of the urinary levels of VMA and NA for 71 salesman (mean +/- SD, 40.6 +/- 11.7 years of age) in a field study was significantly positive (r = 0.426, p < 0.001). These results suggest that urinary VMA mostly reflects NA, but the excretion rate of VMA is slower than that of NA.

Adult↗

PubMed1999

Association of working hours with biological indices related to the cardiovascular system among engineers in a machinery manufacturing company.

A field survey of 278 engineers (20-59 years) in a machinery manufacturing company was conducted to investigate the association of working hours with biological indices related to the cardiovascular system (heart rate variability, blood pressure and serum levels of magnesium, dehydroepiandrosterone sulfate and cholesterol). Average working hours (defined as <"hours at workplace" + "half a commuting time">) and sleeping hours in this study were 60.2 +/- 6.3 hr/week and 6.6 +/- 0.8 hr/day respectively. There were no significant relationships between working hours and biological indices related to the cardiovascular system, but sleeping hours was closely related to working hours negatively. Furthermore, the serum DHEA-S level was significantly related to sleeping hours positively. Combining these two results, it appeared that long working hours might lower the serum DHEA-S level due to the reduction of sleeping hours.

Adult↗

PubMed1999

Effect of working hours on cardiovascular-autonomic nervous functions in engineers in an electronics manufacturing company.

A field survey of 147 engineers (23-49 years) in an electronics manufacturing company was conducted to investigate the effect of working hours on cardiovascular-autonomic nervous functions (urinary catecholamines, heart rate variability and blood pressure). The subjects were divided into 3 groups by age: 23-29 (n = 49), 30-39 (n = 74) and 40-49 (n = 24) year groups. Subjects in each age group were further divided into shorter (SWH) and longer (LWH) working hour subgroups according to the median of weekly working hours. In the 30-39 year group, urinary noradrenaline in the afternoon for LWH was significantly lower than that for SWH and a similar tendency was found in the LF/HF ratio of heart rate variability at rest. Because these two autonomic nervous indices are related to sympathetic nervous activity, the findings suggested that sympathetic nervous activity for LWH was lower than that for SWH in the 30-39 year group. Furthermore, there were significant relationships both between long working hours and short sleeping hours, and between short sleeping hours and high complaint rates of "drowsiness and dullness" in the morning in this age group. Summarizing these results, it appeared that long working hours might lower sympathetic nervous activity due to chronic sleep deprivation.

Adult↗

PubMed1999

[A clinical study on renal pelvic and ureteral tumor associated with bladder tumor with special reference to risk factors of subsequently recurrent bladder tumor].

PURPOSE: The purpose of this report is to analyze the clinical feature of renal pelvic and/or ureteral tumor (RUT) associated with bladder tumor (BT) with special reference to risk factors of subsequently recurrent BT. METHODS: Of the 49 patients with RUT who underwent surgery and were diagnosed pathologically as transitional cell carcinoma at the Department of Urology, Osaka National Hospital from April 1986 to October 1996, 20 patients (40.8%) had associated BTs. These patients were categorized to the following 4 groups, Group 1: 5 patients with BT preceding RUT, Group 2: 5 patients with concomitant BT, Group 3: 10 patients with subsequent BT following RUT operation and Group 4: 29 patients without any associated BT. The clinical course of these 4 groups were studied and compared with each other retrospectively. RESULTS: In group 1, the first BTs preceded RUTs by 19 to 81 months (mean 54.6 months). And during this relatively long period, the preceding BTs were treated by TUR for each recurrence, 1 to 9 times (mean 5.2 times). Two of 5 were bilateral RUT cases, which were observed only in this group. In group 2, the prognosis were relatively poor (5-year survival rate: 0%), because all RUTs of this group were high stage. And also the concomitant BTs were showing invasive feature during the observation period, despite they were superficial at first. Thus 3 of 5 underwent radical cystectomy. On the other hand, in group 3, the subsequent BTs, which developed at 2 to 26 month (mean 13.4 month) after RUT operation, were all superficial and resectable by TUR. The 5-year disease specific survival rate was 50% in group 1, 0% in group 2, 63.5% in group 3, 64.9% in group 4. Group 2 had the most poor prognosis. However there was no significant difference in prognosis among the 4 groups. Incidence of preoperative urine positive cytology was significantly higher in group 3, than in group 4 (87.5% vs. 44.8%). CONCLUSIONS: These results indicated that the RUTs with associated BTs have distinct clinical features depending on the sequence of association with the BTs. Especially the RUTs with concomitant BTs should be watched carefully as a high risk group with poor prognosis and possible development of invasive BTs. Positive urine cytology prior to RUT operation may reflect biological activity of tumor cell for dissemination in the lower urinary tract and we suggested preoperative urine cytology was possible predictor of subsequently recurrent BTs after RUT operation in this study.

Adult↗

PubMed1999

[A case of crossed fused kidney with simple ureterocele].

A 32-year-old man consulted Osaka National hospital with chief complaints of dysuria and macrohematuria. DIP and CT revealed that the right kidney deviated to the lower pole of the left kidney and they fused together. The right ureter crossed over the supine. The calcified shadow existed in the lower end of the left ureter with cobra head image. He had no external anomalies. Under diagnosing crossed fused kidney (inverted L shaped) complicated the left ureterocele with a stone, transurethral incision of ureterocele (TUI) was performed. We made transverse incision and extracted stone, 7 mm in size (calcium oxalate 96% and calcium phosphate 4%). Three months later after the operation, IVP, CG and VCG revealed the down-sized ureterocele and no VUR. Crossed renal ectopia complicated many anomalies about 50%. Among them anomalies of the urinary tract was most frequent about 30%. But crossed renal ectopia with ureterocele wasn't reported so far in Japanese literature.

Adult↗

PubMed1999

[Correlation between intraoperative hemodynamic instability and postoperative renal dysfunction].

We studied whether postoperative renal dysfunction could be predicted from patient's preoperative conditions and the hemodynamics during operation. We evaluated intraoperative hemodynamics using mean value and coefficient of variation (CV) of heart rate and blood pressure during operation. Patients at high risk for renal damage were (1) elderly patients, (2) patients with pre-existing renal disease, (3) patients receiving cancer chemotherapy, and (4) patients having emergency surgery. We did not find a positive correlation between renal dysfunction and hypotension during operation. Large changes of CV of systolic pressure and diminutive changes of CV of diastolic pressure were associated with increased risk of postoperative renal dysfunction. It was difficult to predict postoperative renal complications only with patient's preoperative conditions and the hemodynamics during operation in this study.

Adult↗