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Biomedical subjects

K Oka

Publications and source records attributed to K Oka.

At least 163 records · Page 9Linked to original sources
PubMed1998

Stereochemistry and putative origins of flavanones found in post-administration urine of the traditional Chinese remedies shosaiko-to and daisaiko-to.

Optically active flavanones, dihydrowogonin and dihydrooroxylin A, were found in the urine of healthy volunteers who orally received the traditional Chinese remedies Shosaiko-to and Daisaiko-to on separate occasions. These remedies, which consisted of dried extracts of Scutellariae Radix and other herbs, contained the metabolic precursors of the flavanones, but not the flavanones themselves, in stoichiometrically sufficient amounts. Structures and stereochemistry of the flavanones were elucidated by UV, circular dichroism (CD), electron impact (EI)-MS and 1H-NMR analyses, showing that the biotransformations from the corresponding flavones, wogonin and oroxylin A, were stereoselective with a preference for the S-enantiomers. The putative origins of the flavanones were confirmed in terms of pharmacokinetics. Renal excretion-time data of the flavanones and the flavones suggested that the stereoselective transformations might have occurred in the intestinal tract as a result of microfloral metabolism before absorption.

Adult↗
PubMed1998

Third ventricular neuroepithelial cyst originating from the massa intermedia--case report.

A 47-year-old female presented with a 3-year history of progressive emotional disturbance. Computed tomography and magnetic resonance imaging revealed a cyst in the third ventricle causing hydrocephalus. Endoscopic surgery found the cyst originated at the massa intermedia. Histological examination confirmed the diagnosis of neuroepithelial cyst. Neuroepithelial cyst originating from the massa intermedia may be due to persistence of neuroepithelial crest at this location.

Cerebral Ventricles↗
PubMed1998

Comparison of high and moderate intensity of strength training on mood and anxiety in older adults.

This study was designed to examine the psychological benefits of anaerobic exercise for older adults. Specifically, strength training was employed to examine the effects on mood and anxiety in a group of healthy but sedentary older women. 36 women (mean age = 68.5 yr.) were randomly assigned to groups given high intensity or moderate intensity strength training or to a control group. Strength training was conducted three days a week for 12 weeks. After the training period, both high and moderate strength-training programs produced marked improvements in muscle strength and body composition compared to the control subjects. The average improvements in the high and moderate intensity strength-training groups for muscle strength were 40.5 and 35.5%, respectively, and for percent body fat 1.52 and 2.50%, respectively. As for psychological changes, both training groups significantly improved positive mood (vigor), and the moderate intensity group significantly reduced trait anxiety compared to means of the control group. Also, both training groups showed some decrease in tension and state anxiety after the training period. These findings provide evidence for the effectiveness of anaerobic training to enhance perception of psychological well-being in older women. A moderate intensity rather than high intensity of training regimen may be more beneficial for sedentary older women to improve psychological health.

Adult↗
PubMed1998

Examination of nerve distribution to masticatory muscles using a silicone permeation technique.

The detailed anatomical distribution of nerves throughout the human body has generally been studied by dissection of fixed cadavers in liquid. In this traditional method, it is difficult to maintain the position of nerves on their respective muscles. It is also difficult to keep the distributed form of the nerves. To understand the morphology of nerves, it is essential to determine their location and distribution precisely. In this study the masseter muscle was removed from a cadaver after fixation with formalin. The muscle was then permeated with silicone using the following procedure. The muscle fixed by 10% formalin was dehydrated with alcohol. After dehydration, alcohol was replaced with methylene chloride. The sample was permeated by silicone in a permeater. Following dissection, enamel was applied to the nerve by hand to fix its position. This new permeation method provided excellent localization of nerves innervating the muscle and has the added advantage of providing a three-dimensional structure of neural anatomy similar to the casting procedures used to visualize blood vessels.

Diffusion↗
PubMed1998

[Topical treatment of onychomycosis by occlusive dressing using bifonazole cream containing 40% urea].

Topical treatment with an antifungal agent was performed in 70 cases of onychomycosis (69 cases of tinea unguium and 1 case of Candida onychomycosis). The patients were treated every night by occlusive dressing using bifonazole cream containing 40% urea, and then by simple application of 1% bifonazole solution in the morning. During the treatment period, the softened affected nails were removed as completely as possible with nail clippers and files. The nails were observed every two weeks, and the efficacy was evaluated after 12 weeks. Two cases were excluded and 28 cases dropped out leaving 40 cases for efficacy evaluation. Among the 40 patients, 20 appeared to be mycologically negative (mycological cure rate: 50.0%). Clinical response was judged by the changes in opacity and thickness of the nails. Nine patients were evaluated as showing "marked improvement" and 16 as showing "improvement" (improvement rate: 62.5%). Erosion was noted as an adverse reaction in 2 patients. In one patient, treatment was stopped and the lesion was improved by antibiotic ointment, and in another, treatment was resumed when erosion was cured by discontinuation of the treatment. These results suggest that the topical treatment of onychomycosis by occlusive dressing is a useful method for those patients who have difficulties in or do not wish to be treated with oral antifungal agents.

Administration, Topical↗
PubMed1998

Estimation of residual stress in dental porcelain by laser-Raman spectroscopy.

Residual stress in the surface of dental porcelain was estimated using laser Raman spectroscopy. Sixteen different magnitudes of residual stress were generated in commercial porcelain disks by tempering, ion exchange, and slow cooling. The specimens were analyzed using a laser-Raman spectrometer with an Ar+ laser. The Raman shift of the largest peak near 500 cm-1 originating from silica was used as an indicator of the level of residual stress. For comparison, the residual stress in the specimen was estimated by the indentation micro-fracture method. The Raman shift of the porcelain increased with increasing residual stress at 3.7 x 10(-2) cm-1/MPa (R2 = 0.89). The increase in the Raman shift corresponded to the increase in compressive stress. In addition, the value of full width at half maximum on the peak corresponded to the residual stress (-1.57 x 10(-1) cm-1/MPa: R2 = 0.82). These results revealed that the increase of residual stress in porcelain clearly appears on the Raman spectrum as an increase in the Raman shift. It is thus feasible to estimate residual stress in porcelain by laser-Raman spectroscopy.

Aluminum Silicates↗
PubMed1998

[A case of papillary cystadenoma of the epididymis].

We report a case of papillary cystadenoma of the right epididymis in a 48-year-old man. He consulted our hospital complaining of a small, painless mass at the upper pole of the right testis. There did not seem to be any remarkable problem of the mass. At 52 years old, the mass caused him pain, we diagnosed this case as chronic epididymitis, and performed right epididymectomy. On cut section, the tumor was multicystic and well encapsulated. The fluid within the cystic spaces was hemorrhagic. Microscopically, multimicrocysts were covered by tumor cells, which did not show any atypism or mitotic features. A papillary growth pattern was formed by vacuolated tumor cells around the capillaries in the microcysts, and a diagnosis of papillary cystadenoma of the epididymis was made. Papillary cystadenoma of the epididymis is considered a comparatively uncommon disease. To our knowledge, about 50 cases have been reported in the world literature, and this is the 17th case in Japan. Histologically, this tumor is similar in appearance to well-differentiated renal cell carcinoma, so it should be differentiated from metastatic renal cell carcinoma and multicystic papillary adenocarcinoma of the rete testis. The patient remains well with no evidence of recurrence or complication 8 months after excision. There is no evidence of renal cell carcinoma, nor features of von Hippel-Lindau's disease in this patient or his family.

Cystadenoma, Papillary↗
PubMed1998

Dispensability of p53 degradation for tumorigenicity and decreased serum requirement of human papillomavirus type 16 E6.

Certain types of human papillomavirus (HPV), such as types 16 and 18, are etiological agents for carcinogenesis of the uterine cervix. These HPVs have two oncogenes, E6 and E7, that have transforming activities in established murine cells. Tumorigenicity and decreased serum requirement for cell growth are conferred by the E6 gene, whereas anchorage-independent growth is mainly governed by the E7 gene. To understand the mechanism of cellular transformation by the HPV16 E6 gene, we examined three mutant E6 proteins defective for p53 binding, p53 degradation, or transactivation of the adenovirus E2 promoter for the ability to induce tumorigenicity and decreased serum requirement. The results showed that tumorigenicity and decreased serum requirement were associated with the ability of E6 to bind to p53, although the subsequent degradation of p53 was not required for these functions.

Animals↗
PubMed1998

[A case of clear cell meningioma originating from the cerebellar tentorium].

We report herein on a case of clear cell meningioma originating from the cerebellar tentorium, surgically treated by occipital transtentorial approach (OTT). A 67-year-old woman was admitted to our hospital in September, 1996, complaining of gait disturbance. MRI revealed an isointense mass on T1 and T2 WI, clearly enhanced with gadolinium in the right upper cerebellum originating from the tentorium. A left vertebral angiogram showed tumor stain from the right superior cerebellar artery. The tumor was subtotally removed by OTT on September 24, 1996. Gamma knife radiosurgery was performed for regrowing tumor 6 months after surgery. Histological examination revealed that the tumors were composed of sheets of clear, glycogen-rich cells and lobulated by thin connective tissues. There were no malignant findings, but some tumor cells had infiltrated into the cerebellar cortex. Immunohistochemistry showed that tumor cells were positive for EMA and vimentin, but negative for keratin. MIB-1 staining index was 7.02%. From these findings, this case was diagnosed as a typical clear cell meningioma originating from the cerebellar tentorium. From a review of the literature including our case, clear cell meningioma may be clinicopathologically malignant, so careful follow-up will be necessary.

Aged↗
PubMed1998

[Radiotherapy in the treatment of brain metastasis from small cell lung carcinoma: study on appropriately controlled dose].

Fifty-two brain metastatic lesions occurring in 20 patients with small cell lung carcinoma (SCLC) were irradiated, and then the relationship between tumor size, dose and control was clinically and histopathologically studied. Lesions of 8 mm in diameter and those of 10 mm in diameter were determined to be controllable by irradiation at about 38 Gy and 42 Gy, respectively. According to size-dependent curative minimum doses, the lesions could be divided by the 10 Gy/ 5fr/wk method into controlled and non-controlled groups with the curve expressed as dose (Gy) = 15.27 log10 [tumor volume (mm3)] +0.6. Based on these results, tumors of 2 mm and 3 mm in diameter were estimated to be controllable at 14 and 20 Gy, respectively. Thus prophylactic cranial irradiation (PCI) in the treatment of SCLC was thought to be not always necessary if early treatment of small metastatic lesions, detected by Gd-DTPA-enhanced MRI could be achieved. The optimal interval between follow-up examinations was thought to be 1 month during the first two years after the diagnosis of SCLC, and then 3 months after that. In addition, the omission of PCI can save many patients who do not actually require PCI from suffering its adverse effects.

Aged↗
PubMed1998

Clinical evaluation of transfusion of prestorage-leukoreduced apheresis platelets.

UNLABELLED: With increased use of platelet concentrate (PC) in recent years, adverse reactions to PC transfusion have received much clinical attention. Most of these reactions stem from white blood cells (WBC) contaminating the transfused PC. Several are thought to be preventable by removing WBC before PC storage. METHODS: We routinely filtered apheresis PC either during collection or immediately afterwards and monitored various indicators of platelet quality during storage. After transfusion to patients, transfusion efficacy and the type, severity, and frequency of posttransfusion side effects were compared with those of a control group in which PC was filtered at the bedside. RESULTS: Prestorage-filtered PC contained an average of 3.1+/-0.7 x 10(11) platelets and 0.9+/-1.2 x 10(6) contaminating leukocytes. Measurement of platelet function and metabolic indicators revealed normal values throughout the storage period. CD62 measurement revealed no undue platelet activation after filtration or during the storage period. Cytokine, histamine, bradykinin, and complement levels showed no significant increase after filtration or during storage. Transfusion efficacy and overall side effect incidence rates were similar for the prestorage- and bedside-filtered groups, but reactions of the bedside-filtered group included serious reactions such as breathing difficulties and shock. No serious reactions were noted in the prestorage-filtered group. CONCLUSION: Filtering PC before storage has no adverse effect on PC quality and may reduce the severity of post transfusion side effects.

Blood Platelets↗
PubMed1997

Biphasic modulation in the trigeminal nociceptive neuronal responses by the intracerebroventricular prostaglandin E2 may be mediated through different EP receptors subtypes in rats.

To determine which prostaglandin E2 (PGE2) receptor subtypes are involved in the brain-derived PGE2-induced changes in nociception, we injected synthetic EP1, EP2 and EP3 receptor agonists (0.01 fmol to 10 nmol) into the lateral cerebroventricle (LCV) of urethane-anesthetized rats and observed the changes in the responses of the wide dynamic range (WDR) neurons in the trigeminal nucleus caudalis to noxious pinching of facial skin. The enhancement and suppression of the nociceptive responses of the WDR neurons were observed after the LCV injection of MB28767 (an EP3 receptor agonist) at a low dose range (1-100 fmol) and 17-phenyl-omega-trinor PGE2 (an EP1 receptor agonist) at high doses (1-10 nmol), respectively. Furthermore, the suppression of nociceptive neuronal responses after the LCV injection of PGE2 (1 nmol) was completely blocked by SC19220 (an EP1 receptor antagonist, 300 nmol). On the other hand, butaprost (an EP2 receptor agonist) at any doses tested (0.1 fmol to 1 nmol) had no effect on the nociceptive responses. The LCV injection of MB28767 (10 fmol) and 17-phenyl-omega-trinor PGE2 (1 nmol), which respectively enhanced and suppressed the nociceptive neuronal responses, did not affect the responses of the low threshold mechanoreceptive neurons to innocuous tactile stimuli. These results provide electrophysiological evidence that brain-derived PGE2 induces mechanical hyperalgesia and hypoalgesia through EP3 and EP1 receptors, respectively, in the rat.

Analgesics↗
PubMed1997

Specificity of serine proteinase/serpin complex binding to very-low-density lipoprotein receptor and alpha2-macroglobulin receptor/low-density-lipoprotein-receptor-related protein.

Very-low-density lipoprotein receptor (VLDLR) and alpha2-macroglobulin receptor/low-density-lipoprotein-receptor-related protein (alpha2MR/LRP) are multifunctional endocytosis receptors of the low-density lipoprotein receptor family. Both have been shown to mediate endocytosis and degradation of complex between plasminogen activators and type-1 plasminogen-activator inhibitor (PAI-1) by cultured cells. We have now studied the specificity of binding and endocytosis by VLDLR and alpha2MR/LRP among a variety of serine proteinase/serpin complexes, including various combinations of the serine proteinases urokinase-type and tissue-type plasminogen activators, plasmin, thrombin, human leukocyte elastase, cathepsin G, and plasma kallikrein with the serpins PAI-1, horse leukocyte elastase inhibitor, protein C inhibitor, C1-inhibitor, alpha2-antiplasmin, alpha1-proteinase inhibitor, alpha1-antichymotrypsin, protease nexin-1, heparin cofactor II, and antithrombin III. Binding was estimated with radiolabelled ligands in ligand blotting analysis and microtiter well assays. Endocytosis was estimated by measuring receptor-associated protein (RAP)-sensitive degradation of radiolabelled complexes by Chinese hamster ovary cells transfected with VLDLR cDNA and by COS-1 cells, which have a high endogenous expression of alpha2MR/LRP. We found that the receptors bind with high affinity to some, but not all, combinations of plasminogen activators and thrombin with PAI-1, protease nexin-1, protein C inhibitor, and antithrombin III, while complexes of many serine proteinases with their primary inhibitor, i.e. plasmin/alpha2-antiplasmin complex, do not bind, or bind with a very low affinity. Both the serine proteinase and the serpin moieties contribute to the binding specificity. The binding specificities of VLDLR and alpha2MR/LRP are overlapping, but not identical. The results suggest that VLDLR and alpha2MR/LRP have different biological functions by having different binding specificities as well as by being expressed by different cell types.

Amyloid beta-Protein Precursor↗
PubMed1997

Breast carcinoma epithelial cells express a very low-density lipoprotein receptor variant lacking the O-linked glycosylation domain encoded by exon 16, but with full binding activity for serine proteinase/serpin complexes and Mr-40,000 receptor-associated protein.

Very-low density lipoprotein receptor (VLDLR) belongs to the low-density lipoprotein receptor family of endocytosis receptors. It binds a variety of different ligands, including apolipoprotein E, Mr-40,000 receptor-associated-protein (RAP), and some serine proteinase/serpin complexes. We previously demonstrated the occurrence of two forms of VLDLR in SDS/PAGE, migrating with Mr 105,000 and Mr 130,000, respectively [Heegaard, C. W., Simonsen, A. C. W., Oka, K., Kjøller, L., Christensen, A., Madsen, B., Ellgaard, L., Chan, L. & Andreasen, P. A. (1995) J. Biol. Chem. 270, 20,855-20,869]. We now demonstrate that these two forms correspond to forms with the absence (type-II) and presence (type-I) of the O-linked glycosylation domain encoded by exon 16, respectively. We show that the two forms have the same binding affinity to RAP and serine proteinase/serpin complexes. Using reverse transcription and PCR, we demonstrate that the splice variation giving rise to the two forms is highly cell specific. In particular, we demonstrate that human breast carcinomas express predominantly or exclusively the variant lacking exon 16. By immunohistochemistry, we demonstrate that VLDLR is mainly expressed by the epithelial cancer cells in these carcinomas. The VLDLR variant expressed by epithelial cancer cells could function in the clearance of cell-surface-associated serine proteinase/serpin complexes in breast carcinomas.

Amino Acid Sequence↗
PubMed1997

Prostaglandin E2 may induce hyperthermia through EP1 receptor in the anterior wall of the third ventricle and neighboring preoptic regions.

We have previously reported that intracerebroventricular injection of prostaglandin E2 (PGE2) induces hyperthermia possibly through EP1 receptors in the rat. In the present study, to determine the sites in the brain where PGE2 induces hyperthermia through EP1 receptors, we microinjected an EP1 receptor agonist, 17-phenyl-omega-trinor PGE2 (17-Ph-PGE2, 100 ng) into different sites in the rat brain and observed the colonic temperature (Tco) for 2 h in a 23 +/- 1 degrees C environment. Responsive sites where 17-Ph-PGE2 (100 ng) produced a rise in the Tco of more than 1.1 degrees C within 60 min after injection were found in the medial preoptic area, the subchiasmatic portion of the median preoptic nucleus, the anterior wall of the third ventricle (A3V) and the ventral portion of the diagonal band of Broca. Among these sites, the A3V was the most responsive. In contrast, microinjection of neither butaprost (an EP2 agonist, 100 ng) nor M&B28767 (an EP3 agonist, 100 ng) into these four sites had any effect on the Tco. Intracerebroventricular pretreatment with SC-19220 (an EP1 antagonist, 100 microg) inhibited the rise in the Tco which was induced by microinjection of PGE2 (50 ng) into the A3V. These results thus suggest that PGE2 induces hyperthermia by stimulating EP1 receptors in the A3V and the neighboring preoptic region.

Alprostadil↗
PubMed1997

Extrashot-ODS, a syringe-type minicolumn sample injector for a reversed-phase high-performance liquid chromatographic column. Application to antiepileptics in human sera.

Extrashot-ODS (EXS-ODS) is a syringe-type minicolumn developed for sample injection into reversed-phase high-performance liquid chromatographic columns. EXS-ODS consists of (a) a stainless-steel needle fitted to an ordinary syringe-loading sample injector for HPLC, (b) a 45-microl minicolumn tube made of polytetrafluoroethylene (PTFE) and packed with ODS-silica and (c) a minicolumn holder made of polystyrene, which is connected to the needle on one side and the other side is shaped so as to be fitted with a solvent syringe. Using the device, we simultaneously analyzed three antiepileptics in 20 microl of human sera. First, we introduced a 20-microl serum specimen diluted with 100 microl of buffer solution into the device and, second, 100 microl of distilled water. Then the device was attached to the HPLC injector and 130 microl of methanol were introduced into the HPLC column through the device. Then, reversed-phase HPLC was conducted in the usual manner, with the chromatogram reading at a wavelength of 210 nm for the assays of 5,5-diphenylhydantoin, phenobarbital and carbamazepine. The results obtained by direct peak-height calibration were comparable to those given by the immunological method.

Anticonvulsants↗
PubMed1997

Chromatographic identification of phenolic compounds in human urine following oral administration of the herbal medicines Daisaiko-to and Shosaiko-to.

Chemical identification of the compounds in human urine following administration of the traditional Chinese medicines, Daisaiko-to and Shosaiko-to (Dachaihu-tang and Xiaochaihu-tang in Chinese, respectively), was achieved by using a linear relationship between the logarithm of the capacity factor, log k', and that of the volume fraction of CH3CN, log X(s)(vol), in the aqueous mobile phase: -log k'=A+B log X(s)(vol). Comparison of the slope, B, and the intercept, A, between the urinary compound and its suspected authentic specimen gave satisfactory results in the chemical identification. We applied this method to the initial stage of pharmacokinetic studies on the herbal medicines and identified seven flavonoids and two anthraquinone derivatives in the urine specimens obtained after herbal administration.

Anthraquinones↗