Biomedical subjects

Y Okudaira

Publications and source records attributed to Y Okudaira.

At least 19 recordsLinked to original sources

PubMed2000

The threshold of acetazolamide vasoreactivity as an indicator of maximum cerebral blood volume.

Using xenon-enhanced computed tomographic (Xe-CT) cerebral blood flow (CBF) measurement, we attempted to determine the extent of vasoreactivity indicating reserve autoregulatory potential by comparing maximal cerebral blood volume (CBV) induced by acetazolamide activation (activated CBV) and the resting CBV. We measured the activated and resting CBVs in two different groups by the subtraction technique using contrast-enhanced CT, and measured the resting and activated CBF in both groups to calculate the percentage increase (%deltaCBF). We extracted CBF and CBV in the territory of the middle cerebral artery on both sides separately for each patient, and treated them independently. We then divided the resting CBV values in group B (25 patients, n=50) into 6 subgroups according to their %deltaCBF (below 10%, n=13; 20%, n=7; 30%, n=8; 40%, n=6; 50%, n=6; and over 50%, n=10) and examined the differences from the activated CBVs in group A (12 patients, n=24) by Dunnett's multiple comparison test. Significant differences were seen in subgroups with %deltaCBF exceeding 20% but less than 30%, and in the subgroups with higher %deltaCBF. We consider that %deltaCBF of at least 20% induced by acetazolamide indicates nonmaximal vasodilation, i.e., reserve autoregulatory potential.

Acetazolamide↗

PubMed1997

Hemodynamic compromise as a factor in clinical progression of Sturge-Weber syndrome.

We divided eight patients with Sturge-Weber syndrome into two groups, depending on the presence or absence of clinical progression, and investigated differences in brain hemodynamics between the groups by measuring regional cerebral blood flow (rCBF) before and after acetazolamide activation using stable xenon computed tomography. The most evident difference between the groups was acetazolamide vaso-reactivity (delta CBF) in the primarily healthy area remote from lesion. delta CBF on the contralateral side and in distant areas on the affected side was significantly lower in the group with progression group (unpaired t-test), although both groups had similar delta CBF values in the area of primary lesion. This remote hemodynamic compromise might aggravate the clinical condition. Operations were performed on three patients with progressive disease, resulting in good seizure control with anticonvulsants and a variable degree of improvement in neurological symptoms and vasoreactivity. The neurological improvement appeared to correlate with the size of the resected area and the increase in delta CBF after surgery.

Acetazolamide↗

PubMed1997

Surgical results of perforated gastric carcinoma: an analysis of 155 Japanese patients.

OBJECTIVES: Free perforation of gastric carcinoma accounts for less than 1% incidence of acute abdominal crisis in Japan, and this problem occurs much less frequently in Western countries. To clarify the characteristics of patients with perforated gastric carcinoma (PGC) and to investigate a treatment of choice, we reviewed the data of Japanese patients with PGC. METHODS: A total of 155 cases of PGC reported in the Japanese literature from 1985 to 1994, including one patient of our own experience, were studied. The clinicopathologic features, including tumor stage and patient survival, were analyzed. RESULTS: There were 27 stage I tumors (19%), 16 stage II tumors (12%), 42 stage III tumors (30%), and 55 stage IV tumors (39%). Emergency gastrectomy was done in 128 patients (83%), with the mortality and 5-yr survival rate was 7 and 40%, respectively. The survival of patients was influenced by the gross type of tumor, serosal invasion, lymph node metastasis, stage of the disease, and operative curability. The 5-yr survival rate of stage I and II patients was 76% and that of curatively treated patients was 74%. CONCLUSIONS: Recent Japanese results of emergency gastrectomy for PGC are satisfactory. Long-term survival is expected in curatively treated patients with stage I and II tumors.

Abdomen, Acute↗

PubMed1997

Preoperative assessment of advanced gastric carcinoma using computed tomography.

OBJECTIVES: The role of computed tomography (CT) for the staging of gastric carcinoma is controversial. The purpose of this study was to evaluate the utility of CT in assessing the perigastric spread of advanced gastric carcinoma. METHODS: The study included 56 patients who underwent dynamic CT and laparotomy for the treatment of node-positive gastric adenocarcinoma. Preoperative CT findings were compared with surgical findings, and diagnostic accuracy was estimated. RESULTS: Sensitivity, specificity, and accuracy of preoperative CT in determining the perigastric tumor spreads were 33, 97, and 73% in pancreatic invasion, 36, 97, and 70% in level III lymph node involvement, and 89, 98, and 96% in liver metastasis. Peritoneal dissemination was not detected in 15 of 56 patients (27%), and stage IV disease was not diagnosed correctly in 18 of 40 patients (45%). CONCLUSIONS: Radiologists and surgeons must remember that pancreatic invasion, extended lymph node metastasis, and peritoneal dissemination are sometimes overlooked in CT examination in patients with advanced gastric carcinoma.

Adenocarcinoma↗

PubMed1996

Subclavian artery aneurysm associated with absence of the ipsilateral internal carotid artery.

A 48-year-old male presented with a rare subclavian artery aneurysm associated with absence of the ipsilateral internal carotid artery. The aneurysm was resected and replaced with a Gore Tex artificial graft. Computed tomography, angiography and cerebral blood flow findings suggest that defect of the right internal carotid artery occurred in the developmental stage. There was no past history of trauma, nor histological evidence of inflammatory or sclerotic changes in the aneurysmal wall. The two vascular lesions may have been influenced by a synchronous causative factor in his developmental stage.

Aneurysm↗

PubMed1996

Application of clonal analysis. Differential diagnosis for synchronous primary ovarian and endometrial cancers and metastatic cancer.

Simultaneous involvement of the endometrium and the ovary by carcinoma is a familiar problem in the routine practice of surgical pathology. Such cases may be considered either examples of a single primary carcinoma with metastasis or as synchronous primary neoplasms. The distinction between these two possibilities is made based on clinicopathologic observations, and therefore may not be definitive. In the present study, the authors used molecular techniques to analyze the clonal composition of five cases of concurrent adenocarcinomas of the endometrium and ovary that were clinicopathologically diagnosed as synchronous primary tumors. Patterns of X-chromosome inactivation, mutations in the K-ras gene, mutations or allelic loss of the p53 gene, or human papillomavirus detection were identical in both endometrial and ovarian lesions in three of the cases suggesting that those three cases represented single primary tumors with metastases. In both of the other two cases, the patterns of X-chromosome inactivation clearly demonstrated the presence of independent primary tumors. The application of molecular technology may play an important role for the differential diagnosis between synchronous primary carcinomas and a single carcinoma with metastasis.

Adult↗

PubMed1996

Cerebral blood flow alteration by acetazolamide during carotid balloon occlusion: parameters reflecting cerebral perfusion pressure in the acetazolamide test.

BACKGROUND AND PURPOSE: We attempted to clarify the role of the acetazolamide-reactive mechanism in cerebral hemodynamic autoregulation and to establish a useful method of estimation using the acetazolamide test. METHODS: We examined 18 patients whose cerebral hemodynamics were considered to be normal and whose cerebral blood flow (CBF) was maintained during the balloon occlusion test (BOT) of the internal carotid artery. We measured the mean stump pressure (MSTP) and the mean CBF in the middle cerebral arterial territory using a xenon-enhanced CT system during BOT with and without acetazolamide activation. We obtained the asymmetry ratio (AR=occluded CBF/contralateral CBF) and the increased CBF parameters caused by acetazolamide activation expressed as an absolute value (delta CBF) and a percentage (%delta CBF) for the occluded side. RESULTS: AR during BOT with and without acetazolamide activation differed significantly (P<.001, paired t test) despite the lack of significant MSTP changes. Furthermore, although there was no significant correlation between MSTP and AR without acetazolamide activation, a positive significant correlation was detected with acetazolamide activation (r=.634, P=.005, linear regression analysis). There were significant correlations between delta CBF and MSTP (r=.574, P=.013) and %delta CBF and MSTP (r=.640, P=.004). CONCLUSIONS: We consider that the acetazolamide-reactive mechanism functions as autoregulation at the lower end of the autoregulatory range. The acetazolamide test, using %delta CBF or delta CBF as parameters (which both directly reflect MSTP), is useful for estimating the cerebral perfusion pressure decrease and presence of hemodynamic compromise.

Acetazolamide↗

PubMed1995

Microsatellite instability and alterations in the hMSH2 gene in human ovarian cancer.

The role of the replication error-positive (RER+) phenotype in the development of specific subtypes of sporadic ovarian carcinomas was examined by screening for the presence of microsatellite instability (MI) in 47 tumors. The overall frequency of ovarian MI was 17% only. However, MI occurred in 50% of the ovarian endometrioid-type tumors, which was significantly more often than in all the other histological subtypes combined (8%). Five of the 8 RER+ tumors exhibited most marked type I instability, possibly representing a different mechanism than for the remaining type 2 tumors. The cDNA of the mutation suppression gene hMSH2, the gene most often associated with MI, was screened for alterations in 8 MI-positive and 5 MI-negative ovarian tumors. Only 3 changes were found. Complete loss of hMSH2 mRNA expression was detected in I tumor, while another expressed only an abnormal transcript containing a deletion of exon 3. One additional RER+ serous adenocarcinoma contained a rare polymorphism with a non-conservative amino acid change. One of 8 RER+ tumors showed loss of heterozygosity at the hMSH2 loci. Genetic instability, caused in part by alterations in the hMSH2 gene, may play an important role in the sporadic endometrioid subtype of ovarian tumors. Other mutator-phenotype genes may be responsible for the remaining cases of RER+ ovarian tumors.

Base Sequence↗

PubMed1995

Evaluation of the acetazolamide test. Vasoreactivity and cerebral blood volume.

BACKGROUND AND PURPOSE: We evaluated the potential usefulness of the acetazolamide test by investigating whether acetazolamide vasoreactivity reflected the change in resting cerebral blood volume caused by compensatory vasodilation due to a decline in cerebral perfusion pressure. METHODS: We measured resting and acetazolamide-activated cerebral blood flow with a stable xenon-enhanced CT system and resting cerebral blood volume with the subtraction technique using contrast-enhanced CT in 30 patients with various diseases. These parameters were measured in the anterior, middle, and posterior cerebral arterial territories of both hemispheres separately. We evaluated the statistical relationships between resting cerebral blood volume and vasoreactivity in these three territories, and the significance of the correlations was tested by ANOVA/ANCOVA to adjust for the double entries. RESULTS: Significant negative linear relationships were demonstrated between the resting cerebral blood volume and the change in cerebral blood flow, expressed as a percentage induced by acetazolamide activation, for the anterior (r = -.607, P = .0004), middle (r = -.551, P = .0015), and posterior (r = -.523, P = .0078) cerebral arterial territories and between the resting cerebral blood volume and the increase in cerebral blood flow (absolute values) for the anterior (r = -.512, P = .0164) and middle (r = -.523, P = .0001) but not the posterior (r = -.571, P = .0563) cerebral arterial territories. CONCLUSIONS: The acetazolamide test appears to be useful for the investigation of compensatory vasodilation: the vasoreactivity can be calculated as the increased cerebral blood flow expressed as a percentage or an absolute value, which both reflect cerebral blood volume directly.

Acetazolamide↗

PubMed1995

[Investigation of the role of acetazolamide-reactive mechanism in autoregulation].

PATIENTS AND METHODS: The cerebral blood flow (CBF) and mean stump pressure (MSTP) of 25 preoperative patients were measured during a 15 minute test occlusion of the ipsilateral internal carotid artery (ICA). CBF measurements were carried out by the Xenon/CT system adapted to the Toshiba 20A scanner with 4 min wash-in and 6 min wash-out of 30% Xe. Intra-arterial Xe concentration was calculated from endotidal tube-scanning. We selected two areas: the one fed by the middle cerebral artery (MCA), and the other defined as a unilateral cerebral hemisphere on the axial CT slice through the foramen of Monroe, to obtain CBF. We assessed the asymmetry ratio (AR) of CBF (AR = CBF in occlusion side/CBF in contralateral side) and investigated the correlation and regression of MSTP and AR in 25 cases. Furthermore, in 10 of the 25 patients, we measured the CBF with occlusion of the ICA 20 minutes after intravenous administration of acetazolamide. We evaluated the differences between before and after acetazolamide administration in MSTP and AR (paired t test), and investigated the correlation of and regression between MSTP and AR before and after acetazolamide administration again in these 10 patients. RESULTS: A) In 25 cases; In the cases where MSTP was below 40 mmHg, a straight correlation with significant correlation and regression coefficients (MCA: r = 0.834, P = 0.020; Hemisphere: r = 0.840, P = 0.018) between MSTP and AR recognized. However, this statistical correlation was not seen in the cases where MSTP exceeded 40 mmHg, indicating that relationship could be expressed as horizontal line. B) In 10 cases; (1) AR was found to be significantly decreased after acetazolamide administration (MCA: P = 0.007; Hemisphere: P = 0.004, paired t test), although MSTP remained unchanged. (2) Although the relationship between MSTP and AR could be expressed as horizontal lines without a significant regression coefficient before acetazolamide administration, after that their relationship became a straight correlation with a significant regression coefficient (MCA: r = 0.698, P = 0.025; Hemisphere: r = 0.826, P = 0.003). CONCLUSION: These results suggest that 40 mmHg of MSTP in the cases considered as almost normal is the lower limit of the autoregulatory range. In addition, an acetazolamide reactive mechanism might have a role in autoregulation, and in the lower range down to the lower limit of that the compensated CBF by this mechanism would increase as a progressive reduction of MSTP.

Acetazolamide↗

PubMed1994

[A case of Klippel-Trenaunay-Weber syndrome associated with intracranial multiple angiomas].

A case of Klippel-Trenaunay-Weber syndrome associated with multiple intracranial angiomas was reported. Intracranial angiomas with Klippel-Trenaunay-Weber syndrome is very rare. Only 4 cases are known to this day. A 24-year-old man fell at his workplace and suffered a head injury. He was admitted to our hospital. Neurological examination revealed no abnormality. However, physiological examination demonstrated hyperplasia and cutaneous hemangiomas of left lower leg, malformation of the left eyelid and clouding of the left cornea. CT showed left hemispheric atrophy and subdural effusion. MRI demonstrated multiple flow voids at the left cerebellar hemisphere and at pons. Cerebral angiogram demonstrated left cerebellar AVM and pontine angioma. Feeding arteries of the AVM were left superior cerebellar artery and left posterior inferior cerebellar artery. Those of the pontine angioma could not be identified. No spinal angiomas were revealed. While spinal angiomas associated with this syndrome are known, association of intracranial lesions are rare. Reported anomalies are angiomas, hemi-hypertrophy of skull and brain, carotid occlusion, megadolicoanomaly of the basilar artery, meningioma and glioma. Our case report with cerebral angiomas is the first one in Japan. We postulate that anomaly of our case originated at the Streeter's 2nd-3rd stage or that multiple anomalies occurred. We emphasize that intracranial, spinal or visceral angiomas, which can be fatal if it bleeds, should be routinely examined in Klippel-Trenaunay-Weber syndrome.

Adult↗

PubMed1994

[A case of congenital muscular dystrophy associated with hydrocephalus--CSF dynamics and surgical treatment].

A case of Fukuyama-type congenital muscular dystrophy (FCMD) associated with hydrocephalus was reported. A 15-month-old male, diagnosed as FCMD at 4 months old, revealed progressing large head. CT scan and MRI indicated not only lissencephaly II classified by Dobyn, but dilated ventricular system and subarachnoid space, and these findings radiologically resembled those of brain atrophy. Intracranial pressure and CSF dynamics monitoring revealed high intracranial pressure and high CSF outflow resistance, indicating a high pressure hydrocephalus. V-P shunt made the patient improved not only symptomatically, but physiologically (increased CBF and decreased intracranial pressure and CSF outflow resistance). We concluded that the early diagnosis and treatment of hydrocephalus superimposing the organic disease may prevent secondary damage of the brain, and the intracranial pressure and CSF dynamics monitoring is essential for its diagnosis.

Cerebrovascular Circulation↗

PubMed1993

Improvement of long-term prognosis in patients with ovarian cancers by adjuvant sizofiran immunotherapy: a prospective randomized controlled study.

The effect of immunotherapy using sizofiran (SPG) on the prognosis of patients with ovarian cancers was prospectively studied in a total of 68 patients, who were randomly assigned to either a cisplatin, adriamycin and cyclophosphamide (PAC) therapy group or a PAC plus SPG combination therapy group. The survival rate was significantly higher in patients with stage Ic, II or III cancers treated with the PAC plus SPG combination, compared with the patients treated with PAC alone. In the SPG-receiving patients with stage Ic or more advanced cancers who were treated with four cycles or more of PAC, the outcome was improved (Cox-Mantel, p = 0.074; generalized Kruskal-Wallis, p = 0.032). Similar improvement was also observed in the patients with non-serous adenocarcinomas (Cox-Mantel, p-0.076; generalized Kruskal-Wallis, p = 0.045). No side effects attributable to SPG were recorded. The present results suggest that the use of SPG in combination with long-term chemotherapy improves the postoperative prognosis in ovarian cancer patients.

Adjuvants, Immunologic↗

PubMed1993

[Hormonal therapy in endometrial cancer].

Hormonal agents have been used to treat endometrial cancer since the early 1960s. The response rate for patients with advanced or recurrent endometrial cancer subjected to gestagen therapy has been reported to be about 30%. However, the analysis of the action mechanism of gestagen on endometrial cancer is not complete. Since oral administration of high dose MPA has begun, thrombosis has been reported as an uncommon but severe side effect. The risk factors for thrombosis in patients having gestagen therapy were clarified in the report published by the Ministry of Welfare in 1992. This report emphasized the importance of patient selection for gestagen therapy and cautious management. Besides gestagen therapy, antiestrogen therapy has been tried for the treatment of endometrial cancer. However, tamoxifen therapy was not so effective compared with gestagen. Moreover, antiestrogen-gestagen combination therapy and chemo-endocrine therapy are on trial recently. These trials are attempts to find a more effective regimen for the treatment of endometrial cancer. A recent theme in the study of hormonal therapy is basic investigation concerning the effect of MPA upon the action of growth factor and oncogene expression in endometrial cancer cells. These studies may lead to a molecular biological explanation of the action mechanism of gestagen therapy in future.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1992

Dilatation of the temporal horn in subarachnoid haemorrhage.

CT studies of 50 patients with spontaneous subarachnoid haemorrhage (SAH) and 100 randomly selected patients were reviewed with regard to the size of the frontal and temporal horns of the lateral ventricles. The temporal horn was classified into four grades, based on the size of its posterior portion at the level of the midbrain. The horn was clearly visible in 66% of patients with SAH, but in only 2% of controls. In the SAH group, the temporal horn tended to dilate sooner than the frontal horn after haemorrhage and could be seen clearly in a larger proportion of patients. Thus, assessment of the size of the temporal horn appears to be a simple and sensitive method for assessing ventricular dilatation. In addition, dilatation of the temporal horn may prove to be an important indirect sign suggesting SAH in patients in whom no high density clot is seen on CT.

Adult↗

PubMed1992

[Two cases of blind pouch syndrome].

Case 1. A 39-yr-old male was presented with anemia. Initial blood examination showed remarkable iron deficiency anemia. Small bowel X-ray and abdominal CT examination revealed a dilated tract at the end of the ileum. Surgical operation was done. The surgical specimen showed side to side anastomosis which was reconstructed at the operation for rt. inguinal herniation 46 days after his birth. The oral side of the tract was remarkably dilated. Case 2. A 50-yr-old male was presented with dizziness. He had anemia and clubbed fingers. A small bowel X-ray examination was done and it showed side to side anastomosis in the middle of the small intestine. Surgical operation was performed. The surgical specimen showed side to side anastomosis about 2 m 20 cm from the Treitz' ligament, which was reconstructed during the operation for ileus when he was 10 years old. The blind portion was remarkably dilated. In both case, the anemia was improved after the operation.

Adult↗

PubMed1990

[Primary culture and characterization of human ovarian surface epithelial cells].

Primary culture and characterization of the human ovarian surface epithelial cells were carried out to make a preliminary trial of the histogenetic consideration of common epithelial tumors of the ovary utilizing in vitro systems. Ovarian surface epithelial cells were harvested from strips of surgically excised ovary using an explant culture method and submitted to studies. The cells appeared flat epithelioid in shape and arranged in a cobblestone pattern. Immunocytochemical stainings by the PAP method revealed that these epithelioid cells were keratin and vimentin positive. The cells grew in the medium of RPMI 1640 with 10% fetal calf serum and the growth rate was accelerated significantly when supplemented with hEGF (10 ng/ml) and hydrocortisone (0.5 microgram/ml). When epithelioid cells were cultivated on Matrigel coated glass, some morphological changes were brought about by treating them with TPA (10 ng/ml) or sodium butyrate (1.5 mM). When the cells were cultivated on type I collagen gel, the arrangement of the cells appeared to be mostly monolayer. Grown in Matrigel overlaid on type I collagen gel, the cells grouped and arranged seemingly in spreading branches. Although no malignant transformation has been observed, some morphological changes reminiscent of metaplastic change were seen in some of the cultured cells when the media were treated repeatedly with 5-azacytidine (3 microM), the DNA hypomethylating agent. The results reported may help to some extent to clarify the biological nature of ovarian surface epithelial cells including ovarian tumorigenesis which still remains unknown.

Adult↗

PubMed1989

[Significance of priming of hosts with virus in the tumor-specific immunotherapy model utilizing virus-reactive helper T cell activity].

A tumor-specific immunotherapy model was established utilizing vaccinia virus (VV) in the consideration of clinical application, in which we assessed the significance of priming of hosts with VV to induce in vivo anti-tumor immunity. C3H/HeN mice were pretreated with cyclophosphamide (Cy) to eliminate non-specific suppressor T cell activity and subsequently inoculated (primed) subcutaneously (s.c.) with 10(7)PFU of VV, leading to augmented induction of VV-reactive helper T (VV-Th) cell activities. Four weeks later, the mice were inoculated intradermally (i.d.) with syngeneic X5563 myeloma cells. Six days after the tumor cell inoculation, 5 X 10(7)PFU of VV was injected into the tumor mass 3 times at 2-day intervals. Seven of 10 mice which had received VV-priming and subsequent VV-injection into the tumor mass exhibited complete tumor regression. On the contrary, mice which had received mere intratumoral VV-injection in the absence of VV-priming failed to exhibit appreciable tumor regression. Mice (regressor mice) whose tumor had completely regressed by the above VV-immunotherapy were shown to have acquired systemic anti-tumor immunity which was confirmed by a challenge with syngeneic tumor cells after the tumor regression. In vitro analysis of these immune mice revealed that potent tumor-specific cytotoxic T lymphocyte (CTL) responses were preferentially induced, but with no detectable anti-tumor antibody responses. Such a potent tumor specific immunity was not observed in mice which had received intratumoral VV-injection in the absence of VV-priming.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗