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T Sakaki

Publications and source records attributed to T Sakaki.

At least 271 records · Page 15Linked to original sources
PubMed1992

Tumor cell kinetics and expression of type IV collagen and E-cadherin in a human gingival carcinoma xenograft line in nude mice.

In order to elucidate the relationship of tumor invasion with the expression of E-cadherin and type IV collagen, I carried out immunohistochemical studies on a human gingival carcinoma xenograft line, GK-1, in nude mice. The transplanted tumors were divided into four stages of progression for examination at 5, 7, 10 and 15 weeks after transplantation based on the value of the labeling index for BrdU. The labeling index for BrdU showed its greatest value at seven weeks after transplantation. There was a marked decrease of E-cadherin expression in the tumors at seven weeks after transplantation, and the amount of expression negatively correlated with the labeling index. In addition, the expression of type IV collagen decreased, having a positive correlation with the expression of E-cadherin, and it became discontinuous and unstable. From the above findings, both the decreased expression of E-cadherin and the discontinuous expression of type IV collagen suggest that the tumor cells maintain high invasiveness.

Animals↗
PubMed1992

[AFP producing gastric cancer manifested by metastasis to the tentorium cerebelli; case report and review of the literature].

We report a case of AFP producing gastric cancer manifested by metastasis to the tentorium cerebelli. A 66-year-old male patient was admitted with dysarthria, occipital headache and nausea on May 1, 1990. Neurological examination revealed signs of increased intracranial pressure and the right-sided cerebellar hemispheric signs. CT and MRI showed a round tumor shadow 3cm in diameter, which originated in the right-side tentorium cerebelli and grew in the posterior fossa. Tumor stains fed by the right tentorial artery were recognized by angiography. Serum AFP level was 503.5ng/ml. The patient underwent an operation under general anesthesia in the prone position. The tumor was totally removed via the suboccipital transtentorial approach. Histological examination revealed AFP producing adenocarcinoma. The patient was found to have a gastric cancer after neurosurgical operation, and underwent subtotal gastrectomy by surgeons. Serum AFP level was 254.5ng/ml after removal of metastatic brain tumor, and 5.0ng/ml after subtotal gastrectomy.

Adenocarcinoma↗
PubMed1992

[The focal brain ischemia with disturbance of venous drainage].

The focal brain ischemia with disturbance of cerebral venous drainage often lead to brain edema and hemorrhagic infarction and make mortality and morbidity worse. So we tried to make sure of this fact using a middle cerebral artery (MCA) occlusion model in adult cat. The MCA was exposed by the transorbital approach and temporally obstructed by Zen's clip. We divided the animals into two groups of eight cats. One group is only MCA occlusion group (sham group) and the other in MCA occlusion with disturbance of venous drainage (VRD group). We ligated bilateral external jugular vein (EJV) and internal jugular vein (IJV) and injected embolic sources from the left EJV to obstruct the venous system of cat brain. The pressure of superior sagittal sinus was increased up to 18.7 +/- 5.3 mmHg by this method. A cranial window was made above the ectosylvian gyrus, which has poor anastomosis. The reactivity of pial arteriole and regional cerebral blood flow (rCBF) were observed through the window. And histological brain examination was also performed. The result was that the reactivity of pial arterioles was severely disturbed in VRD group. The area of cerebral infarction and edema were also significantly expanded in VRD group. Considering from these facts, when the venous drainage was disturbed, cerebral perfusion pressure relatively decrease. Because of the decrease in cerebral perfusion pressure, cerebral infarction and edema probably expand to the area so called penumbra.

Animals↗
PubMed1992

[Purine catabolites and pial arteriolar diameter in transient cerebral ischemia].

In transient cerebral ischemia, extracellular purine catabolites and pial arteriolar diameter were measured continuously. Ischemia during one hour was induced by unilateral occlusion of left middle cerebral artery in feline. Extracellular purine catabolites were sampled by in vivo brain microdialysis technique from the gray matter at ectosylvian gyrus. These catabolites were analyzed by HPLC system. Simultaneously, reactivity of pial arteriole was observed and its diameter was measured through the cranial window using intravital microscope and width analyzer. Extracellular concentrations of adenosine, inosine, hypoxanthine and xanthine were found to be 0.80 +/- 0.16 microM, 2.01 +/- 0.95 microM, 4.01 +/- 2.73 microM and 3.93 +/- 2.39 microM, respectively. During ischemia, the concentration of adenosine increased 8.7-fold and arteriolar diameter was 170% of the resting state. These findings in extracellular adenosine concentration and pial arteriolar diameter during ischemia support a role of adenosine in regulation of cerebral blood flow. After reperfusion, arteriolar diameter had returned to 120% of the resting state. But 50 min after reperfusion, pial arteriole began to dilate again coincident with the peak of xanthine concentration. These results suggest that free radicals were produced and could affect pial arterioles 50 min after reperfusion.

Adenosine↗
PubMed1992

[A case of intracranial germinoma responsive to amphotericin B].

A 20-year-old man was admitted to our institution complaining of gradually worsening motor weakness in the right extremities. On admission, the radiological examination revealed a mass located in the left parietal region. On April 4, 1988, a left fronto-parietal craniotomy was performed and the tumor was subtotally removed. The pathological findings of the surgical specimen confirmed no specific tumor, but the presence of a small mingled Candida glabrata supported the diagnosis of fungal granuloma. Amphotericin B (AmB) was administered intravenously for the later enlargement of the tumor. MRI 4 weeks after the beginning of this treatment demonstrated the tumor to be prominently decreased in size. At discharge 3 months later, there was no tumor except only a minimal one in the paraventricular region. However, the recurrence of the tumor was discovered again over the next 8 months. AmB was administered as before, but the tumor continued to be enlarged. In May, 1990, surgery was performed again, and the histological diagnosis was germinoma accompanied with considerable granulomatous reaction. Subsequently, local irradiation was given and complete remission was maintained up to the present time 8 months after irradiation. AmB is a polyene antifungal antibiotic, that has also been reported to enhance the response of antitumor drugs to some tumors on the basis of increased tumor cell permeability. Recent investigations revealed that AmB had immunoadjuvant properties mediated through activated lymphocytes and macrophages, which resulted in an increased host resistance against infectious diseases and even tumors in vivo or in vitro studies. We reported a rare case of intracranial germinoma which responded well to AmB probably through its own antitumor effect caused by immunoadjuvant properties. We discussed the possibility of AmB to be used as immunoadjuvant agent or in combination with other antitumor drugs for the effective treatment of some tumors.

Adult↗
PubMed1992

[Germinoma with granulomatous reaction arising from the corona radiata; case report and review of articles].

We report a rare case of germinoma with granulomatous reaction arising from the corona radiata. This 20-year-old man was admitted to our hospital complaining of progressive motor weakness on the right side. CT demonstrated a poorly demarcated high density area in the left corona radiata, which was heterogeneously enhanced after administration of contrast medium. Moreover, the continuity of the mass to the ventricular wall was confirmed on MRI. At the first operation, subtotal removal of the tumor was performed through a fronto-parietal craniotomy. The diagnosis for the specific neoplasm was not established histologically, but granuloma caused by fungal infection was the most likely cause of the lesion. We tried amphotericin B (AmB), and remission of the tumor was obtained. However, during the following 3 months, the size of the tumor gradually enlarged again. AmB was repeatedly administered, but this time the treatment was ineffective. Six months later, on May 21, 1990, the second operation was performed and histological examination revealed typical germinoma consisting of two-cell pattern. Subsequently, the patient underwent focal irradiation of 33 Gy to the tumor site, and the tumor completely disappeared. As intracranial germinomas are observed to be successfully cured by radiotherapy and/or chemotherapy, choice of the therapeutic management must be carefully determined according to the histological diagnosis, especially in young people. A variety of locations of germinomas and the accompanying granulomatous reactions could create some diagnostic confusion, so great care must be taken in the treatment of much intracranial germinomas.

Adult↗
PubMed1992

[Postoperative intracranial hemorrhage due to vitamin K deficiency: report of two cases].

Vitamin K deficient hemorrhagic diathesis is well known as a cause of infantile intracranial hemorrhage. Its occurrence, however, as a post-surgical complication is rare and has never been reported previously. Two cases are presented here which illustrate the existence of such a hazard. Case 1. A 73-year-old woman admitted with subarachnoid hemorrhage (WFNS IV) underwent microsurgical exploration of a left internal carotid aneurysm, and neck clipping of the aneurysm was performed. She had an uneventful postoperative course, but her neurological condition deteriorated suddenly on the fifth postoperative day. CT scan revealed a large epidural hematoma. Case 2. A 6-year-old boy was admitted due to the dysfunction of a ventriculo-peritoneal shunt system that had previously been placed for hydrocephalus. This dysfunction was thought to be caused by meningitis. Twelve days after ventricular drainage and antibiotic therapy, sudden intraventricular hemorrhage occurred. In both cases, PT and APTT were markedly prolonged, FDP slightly increased and fibrinogen slightly decreased. SFMC was positive in case 2. After the administration of vitamin K, PT and APTT were immediately normalized. Recent reports emphasize the adverse effect of antibiotics that leads to vitamin K deficient hemorrhagic diathesis, especially, in patients in a cachectic state. In these two cases, such a cachectic condition was not observed. We presume that the cause of vitamin K deficiency would be, along with the administration of antibiotics, a preliminary condition of disseminated intravascular coagulation which is encountered in some neurological disorders including subarachnoid hemorrhage. We conclude that attention should be paid for these pitfalls in perioperative neurosurgical care.

Aged↗
PubMed1991

Rotation and interactions of genetically expressed cytochrome P-450IA1 and NADPH-cytochrome P-450 reductase in yeast microsomes.

Rat liver cytochrome P-450IA1 and/or yeast NADPH-cytochrome P-450 reductase was expressed genetically in yeast microsomes. The ratio of P-450IA1 to the reductase was about 17:1 and 1:2 without and with coexpression of the reductase, respectively. Rotational diffusion of P-450IA1 was examined by observing the flash-induced absorption anisotropy, r(t), of the heme.CO complex. In only P-450IA1-expressed microsomes, 28% of P-450IA1 was rotating with a rotational relaxation time (phi) of about 1200 microseconds. The mobile population was increased to 43% by the presence of the coexpressed reductase, while phi was not changed significantly. Increased concentration of KCl from 0 to 1000 mM caused considerable mobilization of P-450IA1. The results demonstrate a proper incorporation of P-450IA1 molecules into yeast microsomal membranes. The significant mobilization of P-450IA1 by the presence of reductase suggests a possible transient association of P-450IA1 with the reductase.

Animals↗
PubMed1991

Two immunologically different isozymes of ascorbate peroxidase from spinach leaves.

Two isozymes of ascorbate peroxidase (AP) from spinach leaves were separated by hydrophobic chromatography and designated AP-I and AP-II. They had similar molecular weights of about 31,000, as determined by gel-filtration, and showed high specificity for ascorbate. One of the two isozymes (AP-II) was purified to homogeneity by SDS-PAGE. Immunoblotting confirmed that antiserum against AP-II reacted with AP-II but not with AP-I. This antiserum inhibited the activity of AP-II, but not that of AP-I. The amino acid composition and partial amino acid sequence of AP-II were determined.

Amino Acid Sequence↗
PubMed1991

Expression of rat liver vitamin D3 25-hydroxylase cDNA in Saccharomyces cerevisiae.

The cDNA coding for the precursor protein of rat liver mitochondrial vitamin D3 25-hydroxylase, cytochrome P450LMT25, was expressed under the control of the yeast alcohol dehydrogenase I promoter and terminator in Saccharomyces cerevisiae AH22 cells. The transformed yeast cells produced a P450LMT25 protein with an almost similar apparent molecular weight as compared with that of the authentic mature enzyme. The expression level of the P450LMT25 hemoprotein was about 5 x 10(4) molecules per cell as determined by reduced CO-difference spectra. The mitochondrial fraction prepared from the transformed yeast cells exhibited both 25-hydroxylase activity toward 1 alpha-hydroxyvitamin D3 and 27-hydroxylase activity toward 5 beta-cholestane-3 alpha, 7 alpha, 12 alpha-triol in a reconstituted system containing bovine adrenodoxin and NADPH-adrenodoxin reductase.

Alcohol Dehydrogenase↗
PubMed1991

Intracerebral hemorrhage in carotid-cavernous fistula.

This report describes a case of traumatic carotid-carvernous fistula which presented as an intracerebral hemorrhage. The usual ocular signs were absent due to an atypical drainage pattern from the cavernous sinus. Engorgement of the deep venous system of the brain due to the carotid-cavernous fistula was thought to have caused the intracerebral hemorrhage.

Arteriovenous Fistula↗
PubMed1991

Acute effect of neodymium yttrium aluminium garment laser on the cerebral cortical structure, blood-brain barrier, and pial vessel behaviour in the cat.

Experimental brain lesions were created by Nd:YAG laser (wave length 1.06 microns) irradiation on the cerebral cortex of anaesthesized adult cats with 20 Watts impacts of 0.5, 1.0, 2.5, and 5.0 seconds exposure time through cranial windows. Histological changes, disruption of the blood-brain barrier (Evans blue extravasation) and pial vessel reaction (large vessels more than 100 microns and vessels smaller than 100 microns) were studied under constant PaCO2, blood pH, and mean arterial pressure. Histological changes of the lesions consisted of a zone of dense coagulation, a pale zone of homogeneous coagulation and an oedematous zone. Evans blue extravasation was uniformly seen extending from the histologically changed area into the surrounding tissue in all experiments. Pial arteries in the area with morphological changes showed pronounced dilatation (100.0 +/- 7.2%) and one third of these arteries were closed by thrombi. Pial arteries in the area of Evans blue extravasation but outside of histological changes also dilated (large arteries 60 +/- 4.1%, small arteries 77 +/- 5.9%). Pial arteries outside of the Evans blue extravasation were affected transiently and only in a very small zone: Within a distance of 200 microns from the Evans blue extravasation, large arteries initially dilated by 41 +/- 8.3%; small arteries dilated within 400 microns (42 +/- 3.7%). Within 4 minutes after irradiation arterial dilatation was again significantly reduced (p less than 0.01). It is concluded that no important vascular changes occur beyond the zones of histologically altered brain tissue.

Animals↗
PubMed1991

Hydroxyethyl-starch in transient experimental focal cerebral ischemia.

In a model of focal cerebral ischaemia in the cat (transorbital occlusion of the middle cerebral artery for 60 minutes, thereafter 6 hours reperfusion by clip removal), hydroxyethyl-starch (HAES) (ELOHES; Leopold Pharma GmbH, Graz, Austria) was administered intravenously before and during the ischaemic episode as a 6% or as a 10% solution in a randomised manner (6 animals each group). The size of the developing cerebral infarct was not significantly different when comparing the 6% and the 10% group with the controls (SALINE). Collateral circulation to the infarct border (pial arteries on the suprasylvian gyrus) was also not significantly different between the two groups, except for the first hour of reperfusion, where vessels of the 6% group were wider than vessels of the 10% group. At the infarct border (ectosylvian gyrus) small resistance vessels were significantly more dilated in the 6% than in the 10% group both during the occlusion period and during the reperfusion episode after removal of the clip. Pial arteries dilated less in both HAES-groups than in the controls. It can be assumed, that HAES-incuded decrease of plasma viscosity led to an elevation of blood flow velocity and blood flow quantity (CBF). But the latter might be counteracted by autoregulation of CBF, i.e. vasoconstriction. Thus, a possible positive effect of HAES might in part be counteracted by autoregulation, which explains that no significant therapeutic effect could be achieved.

Animals↗
PubMed1991

Local cerebral blood flow with prostaglandin E1 or trimethaphan during cerebral aneurysm clip ligation.

This study was performed to examine changes in local cerebral blood flow during hypotensive anaesthesia with either prostaglandin E1 (PGE1) or trimethaphan (TMP). Local cerebral blood flow (LCBF), mean blood pressure (MBP), heart rate (HR), and hourly urine output (UO) were studied in 51 patients undergoing cerebral aneurysm surgery with neuroleptanalgesia (NLA). The incidence of vasospasm after aneurysm surgery, and outcome (Glasgow Outcome Scale) at discharge were evaluated. Measurements of LCBF were made using a thermal gradient blood flow meter. The dose of PGE1 or TMP was adjusted to maintain MBP at about 70 mmHg, and LCBF was studied during and after PGE1 or TMP administration. Hypotensive drugs were discontinued at the completion of aneurysm clipping. After starting PGE1 or TMP, MBP decreased immediately, but HR did not change in either group. The LCBF decreased 30 min after the start of TMP administration and increased immediately after its discontinuation, whereas PGE1 did not affect LCBF. Urine output increased during PGE1 administration but was unchanged during TMP. Neither drug affected surgical outcome or the incidence of vasospasm. These results suggest that PGE1 may be preferable to trimethaphan for hypotensive anaesthesia in cerebral aneurysm surgery because LCBF is maintained.

Adult↗
PubMed1991

Expression of bovine adrenodoxin and NADPH-adrenodoxin reductase cDNAs in Saccharomyces cerevisiae.

Expression of both bovine adrenodoxin (ADX) and NADPH-adrenodoxin reductase (ADR) were examined in Saccharomyces cerevisiae. Three ADX and two ADR expression plasmids were constructed by inserting each of the corresponding cDNA fragments between the yeast alcohol dehydrogenase I promoter and terminator of the expression vector pAAH5N. Plasmids pAX and pMX contained the coding region for the precursor and mature ADX, respectively, while pCMX carried the mature ADX preceded by the mitochondrial signal of yeast cytochrome c oxidase subunit IV (COX IV). Similarly, pMR and pCMR coded for mature ADR without and with the mitochondrial signal of yeast COX IV, respectively. Transformed S. cerevisiae AH22[rho 0]/pAX cells produced the ADX precursor, while AH22[rho 0]/pMX and AH22[rho 0]/pCMX cells produced mature ADX (mat-ADX) and modified ADX (mat-COX/ADX), respectively. Mat-ADX and mat-COX/ADX were found mainly in the cytosolic and mitochondrial fractions, respectively, and showed cytochrome c reductase activity. AH22[rho+]/pMR and AH22[rho+]/pCMR cells produced mature ADR (mat-ADR) and modified ADR (mat-COX/ADR), respectively. Mat-ADR lacking the mitochondrial signal was found in the cytosolic fraction and exhibited cytochrome c reductase activity, while mat-COX/ADR was localized in the mitochondrial fraction, but showed no reductase activity. In an in vitro reconstituted system consisting of both mat-COX/ADX- and mat-ADR-containing fractions, bovine P450scc converted cholesterol into pregnenolone. Thus mat-COX/ADX and mat-ADR produced in the yeast can transfer electrons from NADPH to P450scc.

Adrenodoxin↗
PubMed1991

The influence of the calcium antagonist nimodipine and induced hypertension on the behavior of the cerebral pial arteries, the blood-brain barrier, cerebral edema, and cerebral infarction in cats with one-hour occlusion of the middle cerebral artery.

Thirty anesthetized cats were randomly assigned to one of three groups of 10 cats each: nimodipine treatment, nimodipine treatment combined with induced hypertension, or a control group. The behavior of the cerebral pial arteries was measured by means of microscopic observation through a cranial window. The middle cerebral artery of each cat was clipped for 1 hour via the transorbital approach. Five hours after circulation was reestablished in the middle cerebral artery, Evans blue dye was injected intravenously: 30 minutes later, the animal was killed. Administration of nimodipine or saline in the treated or control group was started 5 minutes before the middle cerebral artery was clipped and maintained until the end of the experiment. Induced hypertension was produced by administration of dopamine during the occlusion. Damage to the blood-brain barrier (BBB) was judged by extravasation of Evans blue dye. Cerebral edema and infarction were evaluated from histological findings. They were most prominent in the control group: the extent of hemisphere affected was as follows (mean +/- standard error): extravasation, 40.5 +/- 8.8%; edema, 43.2 +/- 5.7%; infarction, 35.5 +/- 9.6%. On the other hand, the extravasation of Evans blue dye and cerebral edema were significantly more extensive in the group treated with nimodipine and induced hypertension (extravasation, 28.2 +/- 9.6% of the hemisphere; edema, 30.3 +/- 7.1%) than in the group treated with nimodipine alone (extravasation, 18.5 +/- 8.7% of the hemisphere; edema, 19.4 +/- 6.3%), but the infarction size was similar in both groups (16.6 +/- 4.9% of the hemisphere in the former; 17.0 +/- 6.2 in the latter).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Progesterone metabolism in recombinant yeast simultaneously expressing bovine cytochromes P450c17 (CYP17A1) and P450c21 (CYP21B1) and yeast NADPH-P450 oxidoreductase.

Simultaneous expression plasmids were constructed for bovine adrenal cytochromes P450c17 and P450c21 (pA gamma alpha) and for both P450s together with NADPH-cytochrome P450 reductase (pAR gamma alpha). On introduction of each of the plasmids into Saccharomyces cerevisiae AH22 cells, the transformed yeast strains AH22/pA gamma alpha and AH22/pAR gamma alpha produced about 10(5) molecules per cell of P450c17 and 2 x 10(3) molecules per cell of P450c21. The expression levels of NADPH-cytochrome P450 reductase was about 3 x 10(4) and 6 x 10(5) molecules per cell in the strains AH22/pA gamma alpha and AH22/pAR gamma alpha, respectively. When progesterone was added to growing cell cultures of the transformed yeast strains, the substrate was metabolized more rapidly in the AH22/pAR gamma alpha cells than AH22/pA gamma alpha cells, probably due to overproduction of the reductase. In the AH22/pAR gamma alpha cells, progesterone was first converted into 17 alpha-hydroxyprogesterone to the extent of 82% by the catalysis of P450c17. 17 alpha-hydroxyprogesterone was further converted into 11-deoxycortisol by P450c21 to the extent of 60% of the added substrate. The conversion of progesterone into androstenedione through 17 alpha-hydroxyprogesterone was estimated to be less than 3%, suggesting very low C17,20-lyase activity of P450c17, although other hydroxylation products were detected. Androstenedione was further converted into testosterone by an unknown pathway present in S. cerevisiae cells.

17-alpha-Hydroxyprogesterone↗