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Biomedical subjects

H Oka

Publications and source records attributed to H Oka.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of long-term postoperative interferon-alpha therapy on intrahepatic recurrence after resection of hepatitis C virus-related hepatocellular carcinoma. A randomized, controlled trial.

BACKGROUND: Interferon therapy decreases the incidence of hepatocellular carcinoma in patients with chronic hepatitis C. OBJECTIVE: To evaluate effects of interferon-alpha on recurrence after resection of hepatitis C virus-related hepatocellular carcinoma. DESIGN: Randomized, controlled trial. SETTING: University hospital, medical center, and affiliated hospital in Osaka, Japan. PATIENTS: 30 men were randomly allocated after resection to the interferon-alpha group (n = 15) or the control group (n = 15). INTERVENTION: Patients in the interferon-alpha group received interferon-alpha, 6 MIU intramuscularly daily for 2 weeks, then three times weekly for 14 weeks, and finally twice weekly for 88 weeks. MEASUREMENTS: Recurrence rates after resection. RESULTS: Recurrent tumors were detected in 5 patients in the interferon-alpha group and in 12 control patients. The recurrence rate was significantly lower in the interferon-alpha group than in the control group (P = 0.037). CONCLUSION: Postoperative interferon-alpha therapy appears to decrease recurrence after resection of hepatitis C virus-related hepatocellular carcinoma.

Antineoplastic Agents↗
PubMed2001

Application of ion-exchange cartridge clean-up in food analysis IV. Confirmatory assay of benzylpenicillin, phenoxymethylpenicillin, oxacillin, cloxacillin, nafcillin and dicloxacillin, in bovine tissues by liquid chromatography-electrospray ionization tandem mass spectrometry.

A multiresidue analytical method was developed for the confirmation of benzylpenicillin (PCG), phenoxymethylpenicillin (PCV), oxacillin (MPIPC), cloxacillin (MCIPC), nafcillin (NFPC) and dicloxacillin (MDIPC) in bovine tissues using electrospray ionization liquid chromatography-tandem mass spectrometry (LC-ESI-MS-MS) with a product ion scan mode. All penicillins gave [M-H]-, [M-H-CO2]- and [M-H-141]- as the product ion, when [M-H]- was selected as the precursor ion. Combination of an ion-exchange cartridge clean-up and the LC-ESI-MS-MS method can reliably identify all of these penicillins fortified at a concentration of 0.05 mg/kg in bovine tissues, including liver, kidney and muscle. The limits of confirmation satisfy the maximum residue limits for each of the penicillins established by the World Health Organization, US Food and Drug Administration, European Union and Japan.

Animals↗
PubMed2001

Self and nonself recognition of chiral catalysts: the origin of nonlinear effects in the amino-alcohol catalyzed asymmetric addition of diorganozincs to aldehydes.

Asymmetric addition of dialkylzincs to aldehydes in the presence of (2S)-3-exo-(dimethylamino)isoborneol [(S)-DAIB] exhibits various nonclassical phenomena. The enantiomeric excess (ee) of the alkylation product, obtained with partially resolved DAIB, is much higher than that of the chiral amino alcohol, while the rate decreases considerably as the ee of DAIB is lowered. The asymmetric amplification effects reflect the relative turnover numbers of two enantiomorphic catalytic cycles, where an essential feature is the reversible homochiral and heterochiral dimerization of the coexisting enantiomeric DAIB-based Zn catalysts. The interplay between the thermodynamics of the monomer/dimer equilibration and the kinetics of alkylation reaction strongly affect the overall profile of asymmetric catalysis. The self and nonself recognition of the chiral Zn catalysts is a general phenomenon when (S)-DAIB is mixed with its enantiomer, diastereomer, or even an achiral beta-amino alcohol. The degree of nonlinearity is highly affected not only by the structures and purity of catalysts but also by various reaction parameters. The salient features have been clarified on the basis of molecular weight measurements, NMR and X-ray crystallographic studies of organozinc complexes, and kinetic experiments, as well as computer-aided quantitative analysis.

Journal Article↗
PubMed2001

Drug-resistance gene expression and progression of astrocytic tumors.

To clarify the influence of biochemotherapy on the progression of astrocytic tumors, the expression of O6-methylguanine DNA-methyltransferase (MGMT) mRNA, as well as of other drug-resistance- and drug-sensitivity-related genes such as multidrug resistance gene 1, multidrug resistance-associated protein, glutathione S-transferase-pi, DNA topoisomerase II, and interferon receptor mRNA, and the interferon regulatory factor (IRF)-1 and -2 ratios in gliomas were investigated by quantitative reverse transcription-polymerase chain reaction (RT-PCR). The mean MGMT/beta2-microglobulin (beta2-MG) ratio for 130 neuroepithelial tumors was 8.2 +/- 17.8. The mean ratio of 45 glioblastomas was significantly higher than that for the other 85 tumors. In contrast, the mean of 26 low-grade gliomas was significantly lower than that of other tumors. The mean IRF-1/IRF-2 ratio of 16 other brain tumors that mainly consisted of medulloblastomas was significantly greater than that of the other 114 tumors. Almost no significant differences were observed between primary and recurrent tumors in the expression of any gene, and before and after therapy with corresponding drugs. The mean MGMT/beta2-MG ratio in primary glioblastomas was significantly higher than that in secondary tumors. These findings suggest that native drug resistance is more important than acquired resistance when glioma therapy is considered.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Prognostic value of Ki-67 (MIB-1) and p53 in ependymomas.

To determine whether Ki-67 (MIB-1) and p53 have prognostic value in ependymomas, clinicopathologic study was undertaken in 29 patients with this tumor. The clinical course correlated well with the histological grade according to the World Health Organization (WHO) grading system, and it was the worst in patients with anaplastic ependymoma. The percent expression of MIB-1 and p53 correlated with the histological grade of malignancy. With regard to the subtypes of benign ependymoma, the clinical course was the worst in clear-cell ependymoma, which had a significantly higher expression of MIB-1 and p53 than the other subtypes. Tanycytic ependymoma showed the most benign clinical course and the lowest expression of MIB-1 and p53. Although the WHO grading generally tended to correlate with the clinical course of ependymomas, these two subtypes--clear-cell ependymoma and tanycytic ependymoma--exhibited biological properties different from those of other grade II ependymomas.

Adolescent↗
PubMed2001

Spinal tanycytic ependymomas.

Three cases of spinal tanycytic ependymoma are reported, a man aged 45 years and two women aged 36 and 55 years. Each patient developed gradual paraparesis over a few months prior to admission. Magnetic resonance imaging showed an enhancing, well-circumscribed tumor in the spinal cord in each case. Histologically, the tumors consisted of monotonous proliferation of long spindle cells with markedly eosinophilic cell processes; focally forming perivascular pseudorosettes. The tumor cells were strongly immunopositive for glial fibrillary acidic protein, S-100 protein and vimentin. Ultrastructurally, in addition to massive intermediate filaments, many tumor cells showed abundant microtubules. Well-developed desmosomes and microvilli/cilia-lined microlumina were occasionally observed. The tumors were grossly totally removed and the patients remain recurrence free at 9, 9, and 2 years postoperatively. Reviewing reported cases including our three cases, tanycytic ependymoma may occur frequently in spinal cord, especially in the cervical region of the spinal cord. Since histologically it resembles pilocytic astrocytoma and schwannoma, tanycytic ependymoma should be included in the differential diagnosis of benign spindle cell tumors of the central nervous system.

Adult↗
PubMed2001

Treatment of deep infection following thoracic aorta graft replacement without graft removal.

Deep infection following thoracic aortic replacement constitutes an extremely serious and life-threatening complication, and its treatment remains a challenge to surgeons. We report our experience involving five patients in whom deep infection occurred around the graft. Four of the five patients were treated by emergency surgery and one was treated by elective surgery. Surgical procedures performed including hemiarch replacement in one case, total arch replacement in one case, suspension of aortic valve and ascending aorta replacement in one case, Bentall procedure in one case, and descending aorta re-replacement in one case. Methicillin-resistant Staphylococcus aureus was detected in four patients, methicillin-resistant Staphylococcus epidermidis in one, and Aspergillus in one patient from purulent discharge at the operative site. Reoperative debridement and irrigation drainage were carried out at an early phase of infection. Intermittent irrigation following the reoperation was performed in all cases. In addition, muscle flap filling or omental translocation was carried out in three patients. Although the reported principle of treatment for arterial graft infection is extraanatomical bypass or rereplacement after removal of the infected graft, such procedures may be technically difficult and have a high risk at the thoracic level. Local anti-septic irrigation, administration of antibiotics, and vascular-rich tissue filling are useful procedures, and it appears that it is not always necessary to remove prosthetic grafts.

Adult↗
PubMed2001

Suppression of allergic reactions by royal jelly in association with the restoration of macrophage function and the improvement of Th1/Th2 cell responses.

We studied the immunomodulatory effects of royal jelly (RJ), the principal food source of the queen honeybee. In this study, suppression of allergic reactions by RJ was investigated in DNP-KLH immunized mice (DNP-KLH mice). Oral administration of RJ (1 g/kg) to DNP-KLH mice significantly decreased the serum levels of antigen-specific Ig E and significantly inhibited DNP-KLH mediated-histamine release from mast cells, resulting in the suppression of immediate hypersensitivity reactions of ear skin. In DNP-KLH mice, IFN-gamma (Th1 cytokine) production from CD4+ T cells was suppressed and IL-4 (Th2 cytokine) production from CD4+ T cells was increased as compared to normal mice. On the other hand, RJ improved the balance of Th1/Th2 cell responses from Th2-dominant to Th1-dominant. RJ significantly increased GSH levels in macrophages from DNP-KLH mice. In addition, the administration of RJ to DNP-KLH mice increased IL-12 p40 mRNA expression and NO production, and decreased PG E2 production from macrophages as compared to untreated DNP-KLH mice. These results suggested that RJ suppressed antigen-specific Ig E production and histamine release from mast cells in association with the restoration of macrophage function and improvement of Th1/Th2 cell responses in DNP-KLH mice.

Adjuvants, Immunologic↗
PubMed2001

Multicenter prospective analysis of newly diagnosed hepatocellular carcinoma with respect to the percentage of Lens culinaris agglutinin-reactive alpha-fetoprotein.

BACKGROUND AND AIM: The Lens culinaris agglutinin-reactive fraction of alpha-fetoprotein (AFP-L3) has been reported to be a highly useful marker for hepatocellular carcinoma (HCC) compared with a conventional serum AFP concentration, which allows earlier detection of HCC compared with using other imaging modalities and predicting prognosis after therapy. A collaborative prospective study involving nine Japanese hospitals was conducted to analyze the relationships between the tumor characteristics of a HCC patient and the percentage of AFP-L3/AFP total at the initial detection. METHODS: Between 1 October 1996 and 30 September 1997, a total of 388 patients with newly diagnosed HCC were registered. RESULTS: The cut-off level of the percentage of AFP-L3 was altered from 15 to 10%. The AFP-L3-positive HCC patients demonstrated the characteristics of having an advanced tumor, such as the number of tumors, maximum diameter, tumor spread, portal vein invasion, tumor stage, and tumor classification. With the conventional cut-off level of 15% of the percentage of AFP-L3, the malignant characteristics were more definite than that of 10%. However, no significant differences of serum AFP concentration were observed for malignant characteristics such as maximum diameter and histopathological grading. CONCLUSION: Serum AFP concentration does not reveal a malignancy of HCC, however, the AFP-L3-positive HCC has biologically malignant characteristics, especially portal vein invasion and lower tumor classification, and is an advanced tumor regardless of small tumor size and lower serum AFP concentration. As AFP-L3 shows the tumor characteristics, its presence should be an important factor in the determination of therapy and prognosis of patients.

Aged↗
PubMed2001

Ureteroarterial fistula in a patient with a single functioning kidney.

A rare case is reported of a fistula between the left internal iliac artery and the left ureter in a patient whose left kidney was the only functioning kidney. Internal iliac artery embolization was initially successful in stopping the bleeding, but the fistula recurred when the ureteral stent was removed. Even after embolization, the tissue surrounding a fistula remains very fragile, so the fistula may easily recur as a result of slight injury or inflammation.

Aged↗
PubMed2001

Off-line leukapheresis using leukofiltration for active ulcerative colitis: a case report.

The method of leukocytapheresis for ulcerative colitis (UC) by using extracorporeal circulation (on-line system) has been reported. To perform leukocytapheresis, we have applied leukocyte elimination filters for blood transfusion to leukocytapheresis without using extracorporeal circulation (off-line leukocytapheresis system). Four hundred milliliters of peripheral blood was collected and reinfused through a leukocyte elimination filter. This procedure was repeated 5 times, and up to 2,000 ml of peripheral blood was treated. This method has been applied once a week for 5 weeks. We applied the off-line leukapheresis system to a 31-year-old male ulcerative colitis patient. As a result, the frequency of defecation and the dose of medicine were effectively decreased, and endoscopic finding was also improved. Because of the absence of complications observed with the on-line system, the off-line leukocytapheresis system that we have applied to the clinical patient is simple, safe, and useful.

Adult↗
PubMed2001

A case of Standford type B aortic dissection involving a right-sided aortic arch with mirror-image branching and right-sided descending aorta.

Isolated right aortic arch with mirror-image branching is a rare congenital anomaly. To date, no case has been reported for aortic dissection involving a right aortic arch with mirror-image branching. We report here on a case involving a 58-year-old man in whom expanding type B aortic dissection was demonstrated in the right aortic arch with mirror-image branching and a right descending aorta. The patient was successfully treated by interposition of a prosthetic graft via a right posterolateral thoracotomy approach. We also reviewed the literature.

Aortic Dissection↗
PubMed2001

Management of renal cell carcinoma with inferior vena cava tumor thrombus.

OBJECTIVE: The prognostic implication of radical nephrectomy with inferior vena cava tumor thrombectomy for renal cell carcinoma is still controversial. We investigated the type of renal cell carcinoma with vena cava tumor thrombus for which surgical resection was beneficial. MATERIALS AND METHODS: We retrospectively reviewed the records of 16 patients with renal cell carcinoma and inferior vena cava tumor thrombus. Of these, 10 received surgical treatment and 6 did not. We evaluated the association between the pretreatment serum C-reactive protein (CRP) level and the efficacy of surgery. RESULTS: Among the 8 patients with an elevated pretreatment serum CRP level (CRP > or = 1.0 ng/ml), there was no significant difference of the median disease-specific survival between those who did (20.2 months) and did not undergo surgery (8.2 months; p = 0.1946). On the other hand, among the 8 patients who had a pretreatment serum CRP level within normal limits (CRP < 1.0 ng/ml), the median disease-specific survival of those who did not undergo surgery (80.6 months) was significantly better than that of those who did (50.2 months; p = 0.0136). CONCLUSION: This study suggested that conservative treatment can be recommended for patients with renal cell carcinoma and inferior vena cava tumor thrombus when the pretreatment serum CRP level is normal because tumor progression is usually slow and surgical treatment may actually worsen the prognosis.

Adult↗
PubMed2001

[Multiple primary cancers limited to the urological field].

We analyzed the clinical features of multiple primary cancers arising from the urogenital organs. Between January 1980 and December 1999, 300 patients with renal cell carcinoma (RCC), 661 patients with urothelial carcinoma (bladder cancer and renal pelvic-ureteral cancer) (TCC) and 391 patients with prostate cancer (PC) were treated at our hospital. Of these patients, 20 patients had double genitourinary cancers. The double cancers consisted of RCC and TCC in 1 case, RCC and PC in 6 cases, and TCC and PC in 13 cases. Seven cases had synchronous tumors. The average interval in the metachronous cases was 68 (range: 12-209) months. The age at diagnosis of the second cancer was 68-94 (mean: 77.6) years old. The follow-up period ranged from 4-168 (mean: 38) months; Six patients are alive with no evidence of disease and 6 patients died of cancer. Even when limited to the urological section, the frequency of multiple primary cancers is increasing.

Age Factors↗
PubMed2001

Synthesis and reactivity of a 5-azido analogue of neuraminic acid.

A peracetylated phenyl 2-thioglycoside (1) of a 5-azido analogue neuraminic acid methyl ester was prepared from a known 5-amino precursor by a diazo transfer reaction. Glycosidation of 1 by alcohols proceeded smoothly in CH3CN to give alpha-sialylated products in good yield.

Journal Article↗