Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 55 records · Page 3Linked to original sources

PubMed2001

Chordoid meningioma. A case report.

We report on a 62-year-old woman without Castleman's syndrome diagnosed with chordoid meningioma. A white, encapsulated brain tumor was located in the parietal lobe of the left hemisphere of the cerebrum, adhered to the dura, and was separated from the cerebrum. The tumor revealed a multilobular arrangement of two types of neoplastic cells, and the surrounding myxoid stroma was separated by incomplete fibrous septa. Neoplastic cells consisted of myxomatous and meningothelial cells. The former made up about four-fifths of the tumor, had a vacuolar cytoplasm, and were arranged in a chordoma-like cord pattern. They were floating in myxoid stroma. The latter had an eosinophilic spindle or epithelioid cytoplasm and were disposed in lobules. Coarse eosinophilic materials positive for periodic acid-Schiff stain were deposited among them. Transitional cells between two types of cells were also observed. Both neoplastic cells were positive for vimentin and Leu-7 (CD57) in their cytoplasm, and were consistently negative for epithelial membrane antigen, S-100 protein, and cytokeratin.

Chordoma↗

PubMed2001

Fluvastatin depresses the enhanced lipid peroxidation in vitamin E-deficient hamsters.

Fluvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, has recently been reported to have the antioxidative activity in vitro. However, it is still unclear whether chronic treatment with this drug actually leads to amelioration of the redox status in the body. In this study, we investigated the antioxidative effect of fluvastatin in vivo, using a vitamin E-deficient hamster model, an in vivo model of enhanced oxidative stress. After pre-treatment with a vitamin E-deficient diet for 2 months, fluvastatin, pravastatin or probucol was added to the diet for 1 month. Vitamin E deficiency caused a significant increase in the levels of plasma oxidative stress markers such as 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) and hydroperoxides. Furthermore, there was a significant increase in the oxidizability of plasma lipids in the vitamin E-deficient animals, indicating that the oxidative stress was increased in the circulation. Fluvastatin markedly depressed the above oxidative stress markers in plasma, and significantly decreased the oxidizability of plasma lipids without affecting their levels. Probucol, a reference antioxidant, also showed a similar effect while pravastatin, another HMG-CoA reductase inhibitor, showed only a weak improvement. We suggest that the treatment with fluvastatin leads to a reduction of oxidative stress in vivo, which is mainly derived from its antioxidative property rather than its lipid-lowering activity.

Animals↗

PubMed2001

Mucinous adenocarcinoma of Bartholin gland treated with radiation therapy: a case report.

Adenocarcinoma of Bartholin gland is a very rare disease and its molecular pathological features are poorly delineated. A 92-year-old woman with mucinous adenocarcinoma of Bartholin gland with metastasis to the right inguinal lymph node was treated with radiation therapy alone. Despite intensive radiation therapy, the tumor was locally recurrent and the patient died 10 months after radiation therapy. We searched for the presence of human papillomavirus 16 and 18 DNA and the expression of p53 protein, CA19-9, CEA and MIB-1 antigen. Immunohistochemical study showed that mucinous adenocarcinoma of Bartholin gland produced CA19-9 and CEA.

Adenocarcinoma, Mucinous↗

PubMed2001

Inhibition of p21/Waf1/Cip1/Sdi1 expression by hepatitis C virus core protein.

The possibility of interaction between hepatitis C virus (HCV) core protein and the cell cycle regulator protein p21/Waf1/Cip1/Sdi1 (p21/Waf1) in cultured cells was analyzed. Although colocalization of HCV core protein and p21/Waf1 was not clearly observed, p21/Waf1 expression was much weaker in HCV core protein-expressing cells than in the control. A Northern blot analysis showed nearly the same level of p21/Waf1 mRNA in both cells, suggesting that HCV core protein inhibited p21/Waf1 expression post-transcriptionally. The degradation patterns of p21/Waf1 did not differ significantly in HCV core protein-expressing cells and in the control, suggesting that the stability of p21/Waf1, once it was accumulated in the cell, was not significantly affected by HCV core protein. But this does not necessarily exclude the possibility that synthesis, maturation, and nuclear transport of p21/Waf1 is impaired, or that the degradation of newly synthesized, improperly processed p21/Waf1 is promoted by HCV core protein. The decrease in p21/Waf1 accumulation was partially inhibited by proteasome inhibitors and a calpain inhibitor in both HCV core protein-expressing cells and the control. In vitro kinase assay revealed that a p21/Waf1-mediated inhibition of cyclin-dependent kinase 2 activity was partially negated by HCV core protein. Taken together, the present results suggest that HCV core protein inhibits p21/Waf1 expression post-transcriptionally and impairs the function of p21/Waf1 in the cell.

Blotting, Northern↗

PubMed2001

Oscillatory flow and gas transport through a symmetrical bifurcation.

Axial gas transport due to the interaction between radial mixing and radially nonuniform axial velocities is responsible for gas transport in thick airways during High-frequency oscillatory ventilation (HFO). Because the airways can be characterized by a bifurcating tube network, the secondary flow in the curved portion of a bifurcating tube contributes to cross-stream mixing. In this study the oscillatory flow and concentration fields through a single symmetrical airway bifurcating tube model were numerically analyzed by solving three-dimensional Navier-Stokes and mass concentration equations with the SIMPLER algorithm. The simulation conditions were for a Womersley number, alpha = 9.1 and Reynolds numbers in the parent tube between 200 and 1000, corresponding to Dn2/alpha 4 in the curved portion between 2 and 80, where Dn is Dean number. For comparison with the results from the bifurcating tube, we calculated the velocity and concentration fields for fully developed oscillatory flow through a curved tube with a curvature rate of 1/10, which is identical to the curved portion of the bifurcating tube. For Dn2/alpha 4 < or = 10 in the curved portion of the bifurcating tube, the flow divider and area changes dominate the axial gas transport, because the effective diffusivity is greater than in either a straight or curved tube, in spite of low secondary velocities. However, for Dn2/alpha 4 > or = 20, the gas transport characteristics in a bifurcation are similar to a curved tube because of the significant effect of secondary flow.

Algorithms↗

PubMed2001

Correlation between mutations in the interferon sensitivity-determining region of NS5A protein and viral load of hepatitis C virus subtypes 1b, 1c, and 2a.

In the present study, we analyzed the possible relationship between interferon (IFN) sensitivity-determining region (ISDR) sequence variation of various hepatitis C virus (HCV) subtypes and serum HCV titers in Indonesian patients without IFN treatment. The viremia titers (mean +/- standard deviation) of HCV subtype 1b (HCV-1b) isolates with low (three or fewer) and high (four or more) numbers of ISDR mutations were 5.4 +/- 0.6 and 4.2 +/- 0.9 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Similarly, the viremia titers of HCV-1c isolates with low and high numbers of ISDR mutations were 5.3 +/- 0.6 and <3.0 +/- 0.0 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Also, the virus titers of HCV-2a isolates with low and high numbers of ISDR mutations were 4.3 +/- 0.7 and 3.5 +/- 0.4 log(10) RNA copies/ml, respectively, with the difference between the two groups being statistically significant (P < 0.01). Thus, our results demonstrated that virus load in Indonesian patients infected with HCV-1b, HCV-1c, or HCV-2a correlated inversely with the number of mutations in the ISDR sequence, implying the possibility that the ISDR sequence plays an important role in determining the levels of HCV viremia.

Amino Acid Sequence↗

PubMed2001

Communication Capacity Scale and Agitation Distress Scale to measure the severity of delirium in terminally ill cancer patients: a validation study.

Although valid measurement of the severity of terminal delirium is of great importance in palliative care settings, existing instruments have considerable limitations. In order to quantify patients' communication capacity and agitated behaviour, two new operational observer-rating scales, the Communication Capacity Scale (Communication Scale) and Agitation Distress Scale (Agitation Scale), were validated. Thirty terminally ill cancer patients diagnosed with delirium were evaluated simultaneously by two palliative care physicians blinded to each other's coding using the Communication Scale and Agitation Scale. In addition, the Memorial Delirium Assessment Scale (MDAS), Delirium Rating Scale (DRS) and Sedation Scale were rated by one researcher. Both scales achieved high internal consistency and inter-rater reliability with Cronbach's alpha coefficients of 0.91 and 0.96, and Cohen's kappa values on each item of 0.72-1.00. The principal components analysis resulted in the emergence of only one component for each scale. The total score on the Communication Scale was highly associated with that of the MDAS (rho = 0.78), Sedation Scale (rho = 0.86), and cognitive items from the MDAS and DRS (rho = 0.83). The whole score on the Agitation Scale was significantly correlated with that of the DRS (rho = 0.61) and agitation items from the MDAS and DRS (rho = 0.61). In conclusion, the Communication Scale and Agitation Scale have acceptable reliability and validity to quantify patients' communication capacity and agitation symptoms of terminally ill cancer patients with delirium.

Adult↗

PubMed2001

Glycyrrhetinic acid induced apoptosis in murine splenocytes.

Glycyrrhetinic acid (GA) is known to inhibit glucocorticoid metabolism inhibiting 11beta-hydroxysteroid dehydrogenase (11beta-HSD). Moreover, GA administration to mice has been shown to affect the lymphoid organs through elevation of endogenous corticosterone concentration. The effect of GA administration on thymus has been demonstrated to show that considerable amounts of thymocytes undergo apoptosis by elevated levels of corticosterone in systemic circulation. However, the effect of GA administration on peripheral lymphocytes has remained unknown. In our current study, we demonstrated that a significant involution of spleen as well as thymus occurred within 24 h of a single administration of GA in mice. In addition, a flow cytometric analysis of the splenocytes taken from mice treated with GA showed a significant increase in the number of apoptotic cells which exhibited translocated phosphatidylserine outside the plasma membrane. Furthermore, considerable inhibition of 11beta-HSD activity in GA-treated mice was observed in liver and spleen, resulting in a significant increase in concentration of corticosterone in the blood. These facts showed that the apoptosis of splenocytes was the result of indirect effect of GA through elevated levels of corticosterone. We confirmed this using cultured splenocytes in vitro where no apoptotic effect of GA was observed. We concluded that GA administration induces cell death of not only thymocytes that are naive to corticosterone, but also splenocytes that are usually stable to its physiological concentrations.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2001

Phase transformation of a zirconia ceramic head after total hip arthroplasty.

We report two cases of surface deterioration of a zirconia ceramic femoral head associated with phase transformation after total hip arthroplasty. One head was retrieved at revision due to recurrent dislocation after six years and the other because of failure of the locking mechanism of the polyethylene liner after three years. The monoclinic content of the zirconia ceramics rose from 1% to about 30% on the surface of the heads. SEM revealed numerous craters indicating extraction of the zirconia ceramics at the surface. Surface roughness increased from an initial value of 0.006 microm up to 0.12 microm. This is the first report to show that phase transformation of zirconia ceramics causes deterioration of the surface roughness of the head in vivo after total hip arthroplasty.

Female↗

PubMed2001

Effects of absorbed components of saiboku-to on the release of leukotrienes from polymorphonuclear leukocytes of patients with bronchial asthma.

Previous studies confirmed the efficacy of the Chinese herbal remedy Saiboku-to in patients with steroid-dependent asthma. We studied 8 phenolic compounds, isolated from the urine of patients receiving Saiboku-to, with respect to their effects on leukotriene (LT) release by polymorphonuclear leukocytes (PMN) obtained from 6 patients with atopic asthma and 8 healthy subjects. The compounds (0.01-10 micrograms/ml) were incubated with Ca2+ ionophore (A23187)-stimulated PMN, and concentrations of leukotriene B4 (LTB4) and leukotriene C4 (LTC4) in the supernatant were measured by EIA. Each compound suppressed the release of LTB4 and LTC4 by PMN obtained from healthy and asthmatic subjects. In particular, baicalein and magnolol were 5-10 times more potent than azelastine, an antiallergic drug, and significantly suppressed LTC4 release by PMN obtained from asthmatic patients, as compared with healthy subjects. Suppression of LTC4 release by these compounds may play an important role in the clinical efficacy of Saiboku-to.

Adult↗

PubMed2001

Unmyelinated nerve fibers of the human mandibular nerve.

The aim of this research is to find and to evaluate morphometorically the unmyelinated nerve fibers in the human mandibular nerve using a light microscope. Our report demonstrates for the first time the presence of the unmyelinated nerve fibers of the human mandibular nerve stained by a special method. Our results also indicate that there is a morphometric change with aging in the unmyelinated axons of the nerve.

Adult↗

PubMed2001

Nerve fiber analysis and age-related changes of the human mandibular nerve.

We morphometrically analyzed nerve fibers of the human mandibular nerve with a discriminative staining method that makes it possible to separate nerve fibers into myelinated and unmyelinated fibers. We counted numbers and transverse areas of myelinated axons under the microscope using an on-line image-analyzer. This study revealed the morphometric changes which affect the human mandibular nerve during the aging process.

Aged↗

PubMed2001

Dendritic calcium accumulation regulates wind sensitivity via short-term depression at cercal sensory-to-giant interneuron synapses in the cricket.

An in vivo Ca2+ imaging technique was applied to examine the cellular mechanisms for attenuation of wind sensitivity in the identified primary sensory interneurons in the cricket cercal system. Simultaneous measurement of the cytosolic Ca2+ concentration ([Ca2+]i) and membrane potential of a wind-sensitive giant interneuron (GI) revealed that successive air puffs caused the Ca2+ accumulation in dendrites and diminished the wind-evoked bursting response in the GI. After tetanic stimulation of the presynaptic cercal sensory nerves induced a larger Ca2+ accumulation in the GI, the wind-evoked bursting response was reversibly decreased in its spike number. When hyperpolarizing current injection suppressed the [Ca2+]i elevation during tetanic stimulation, the wind-evoked EPSPs were not changed. Moreover, after suprathreshold tetanic stimulation to one side of the cercal nerve resulted in Ca2+ accumulation in the GI's dendrites, the slope of EPSP evoked by presynaptic stimulation of the other side of the cercal nerve was also attenuated for a few minutes after the [Ca2+]i had returned to the prestimulation level. This short-term depression at synapses between the cercal sensory neurons and the GI (cercal-to-giant synapses) was also induced by a depolarizing current injection, which increased the [Ca2+]i, and buffering of the Ca2+ rise with a high concentration of a Ca2+ chelator blocked the induction of short-term depression. These results indicate that the postsynaptic Ca2+ accumulation causes short-term synaptic depression at the cercal-to-giant synapses. The dendritic excitability of the GI may contribute to postsynaptic regulation of the wind-sensitivity via Ca2+-dependent depression.

Action Potentials↗

PubMed2001

[Clinical experience of in situ extracorporeal shock wave lithotripsy using ESL-500A for bilateral ureteral stones and ureteral stones in a solitary, or a functionally solitary kidney].

Extracorporeal shock wave lithotripsy (ESWL) using ESL-500A was performed for the treatment of 18 cases of bilateral ureteral stones and 3 cases of a solitary or a functionally solitary kidney with ureteral stones from September 1991 to February 2000. Sixteen cases of the former and all 3 cases of the latter were treated by in situ ESWL, and the other 2 cases of bilateral ureteral stones were treated with auxiliary procedures. No residual stones were observed in any cases except for one of bilateral ureteral stones treated by in situ ESWL. The results show that in situ ESWL using ESL-500A seems to be useful for the treatment of bilateral ureteral stones and ureteral stones in a solitary kidney, including a functionally solitary kidney. However, auxiliary treatment will be needed in cases of urinary tract infection, undetectable stones by ultrasonography, or bilateral large stones.

Adolescent↗

PubMed2001

[A case of papillary adenocarcinoma of the prostate which was difficult to diagnose].

We report a case of papillary adenocarcinoma of the prostate found by urethroscopy. An 84-year-old male visited our hospital complaining of initial hematuria in July 1997. No abnormal findings were detected despite repeated urological examinations until endoscopic examination revealed fine papillary tumors in the prostatic urethra along with benign prostatic hyperplasia-like prominent left lobe of the prostate in June 2000. Serum prostate specific antigen (PSA) level was 4.1 ng/ml. He underwent transurethral resection of the urethral tumors and the prominent lobe, which was found to contain packed papillary tumors. Both of these tumors were well differentiated papillary adenocarcinoma most likely originating from the prostate because PSA immunostaining was positive. The prostate was irradiated postoperatively. Papillary adenocarcinoma localized in the prostate is difficult to diagnose preoperatively.

Adenocarcinoma, Papillary↗

PubMed2001

[Transitional cell carcinoma of the ureter with inverted proliferation accompanied with papillary bladder tumor: a case report].

An 85-year-old female was referred to our hospital with chief complaints of right flank pain and gross hematuria. Ultrasonography demonstrated right hydroureteronephrosis and a thumb head-sized solid mass in the lower third of the right ureter. Cystoscopy revealed papillary tumors near the right ureteral orifice. Under the preoperative diagnosis of right ureteral tumor and bladder tumor, transurethral resection of bladder tumor, right nephroureterectomy and partial cystectomy were performed. The gross specimen of the ureter contained a 5 x 3 x 1 cm, polypoid and smooth-surfaced tumor. The pathological diagnosis of the ureteral tumor was transitional cell carcinoma with inverted proliferation, grade 1 >> grade 2. On the other hand, the bladder tumor was papillary transitional cell carcinoma, grade 1. This is a case in which tumor development showed two different types.

Aged↗

PubMed2000

Relationship of EP(1-4) prostaglandin receptors with rat hypothalamic cell groups involved in lipopolysaccharide fever responses.

The action of prostaglandin E(2) (PGE(2)) in the preoptic area is thought to play an important role in producing fever. Pharmacologic evidence suggests that, among the four subtypes of E-series prostaglandin (EP) receptors, i.e., EP(1), EP(2), EP(3), and EP(4), the EP(1) receptor mediates fever responses. In contrast, evidence from mice with EP receptor gene deletions indicates that the EP(3) receptor is required for the initial (<1 hour) fever after intravenous (i.v.) lipopolysaccharide (LPS). To investigate which subtypes of EP receptors mediate systemic infection-induced fever, we assessed the coexpression of Fos-like immunoreactivity (Fos-IR) and EP(1-4) receptor mRNA in nuclei in the rat hypothalamus that have been shown to be involved in fever responses. Two hours after the administration of i.v. LPS (5 microg/kg), Fos-IR was observed in the ventromedial preoptic nucleus, the median preoptic nucleus, and the paraventricular hypothalamic nucleus. In these nuclei, EP(4) receptor mRNA was strongly expressed and the Fos-IR intensely colocalized with EP(4) receptor mRNA. Strong EP(3) receptor mRNA expression was only seen within the median preoptic nucleus but Fos-IR showed little coexpression with EP(3) receptor mRNA. EP(2) receptor mRNA was not seen in the PGE(2) sensitive parts of the preoptic area. Although approximately half of the Fos-immunoreactive neurons also expressed EP(1) receptor mRNA, EP(1) mRNA expression was weak and its distribution was so diffuse in the preoptic area that it did not represent a specific relationship. In the paraventricular nucleus, EP(4) mRNA was found in most Fos-immunoreactive neurons and levels of EP(4) receptor expression increased after i.v. LPS. Our findings indicate that neurons expressing EP(4) receptor are activated during LPS-induced fever and suggest the involvement of EP(4) receptors in the production of fever.

Animals↗

PubMed2000

High growth fraction at 9 grays of radiotherapy is associated with a good prognosis for patients with cervical squamous cell carcinoma.

BACKGROUND: MIB-1, a murine monoclonal antibody, recognizes the Ki-67 antigen of routinely processed paraffin sections after microwave treatment. Cycling cells are positive for MIB-1 in their nucleus, and quiescent cells are negative for MIB-1. The MIB-1 labeling index represents the growth fraction of the cell population. METHODS: A total of 150 cervical biopsy specimens were taken from 75 consecutive patients with cervical squamous cell carcinomas before radiotherapy (RT) and at 9 grays (Gy) of RT and were investigated to analyze the correlation between the MIB-1 labeling index or the deltaMIB-1 labeling index and patient prognosis or local disease control. The deltaMIB-1 index was calculated as the MIB-1 index at 9 Gy minus the MIB-1 index before RT. RESULTS: The mean MIB-1 index was 38% (range, 11-67%) before RT and 54% (range, 15-85%) at 9 Gy. The MIB-1 index at 9 Gy was related to prognosis, including overall survival (P = 0.025), disease free survival (P = 0. 024), and metastasis free survival (P = 0.045). Patients who had a deltaMIB-1 index > 20% showed a trend toward a higher disease free survival rate compared with patients who had a deltaMIB-1 index < 20% (P = 0.093). Neither the MIB-1 index nor the deltaMIB-1 index was associated with local disease control. CONCLUSIONS: The high growth fraction at 9 Gy is regarded as a predictive factor for a good prognosis in patients with cervical squamous cell carcinoma patients who undergo RT alone.

Adult↗