Biomedical subjects

K Kurisu

Publications and source records attributed to K Kurisu.

At least 235 records · Page 13Linked to original sources

PubMed1992

Effect of intracarotid infusion of etoposide with angiotensin II-induced hypertension on the blood-brain barrier and the brain tissue.

This study investigated the effects of the intracarotid infusion of etoposide in combination with angiotensin II (AT II)-induced hypertension on the blood-brain barrier (BBB) and brain tissue in rats. Eighty rats were divided into five groups: Group 1, intravenous infusion of AT II to increase arterial blood pressure; Group 2, intracarotid infusion of etoposide at 22.5 mg/m2 for 10 minutes; Group 3, intracarotid infusion of etoposide at 75.0 mg/m2 for 10 minutes; Group 4, intracarotid infusion of etoposide at 75.0 mg/m2 for 20 minutes; Group 5, intracarotid infusion of etoposide at 75.0 mg/m2 for 10 minutes with AT II-induced hypertension. Evans blue staining of the brain was used as a monitor of BBB disruption. Mean arterial blood pressure over the experimental period in Group 1 increased from 86.3 +/- 1.3 mmHg (mean +/- SEM) to 139.0 +/- 2.4 mmHg, and Group 5 from 85.9 +/- 1.8 mmHg to 137.3 +/- 2.4 mmHg. None of the animals in Group 1 and 2 showed any obvious neurological change, while all the animals in Group 3, 4 and 5 exhibited diminished activity as their sole neurological change throughout the course of the experiment. Slight evidence of BBB disruption was seen in only 25% of the animals in Group 1. Significant BBB disruption was found in the animals in Group 2, 3, 4 and 5. No histological change was observed in any animal in Group 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗

PubMed1992

Primary and secondary culture of rat ameloblasts in serum-free medium.

Enamel is the hardest tissue in vertebrates. Ameloblasts are derived from epithelial cells and are responsible for enamel formation. They secrete enamel matrix components in which amelogenins are the major proteins, the biochemical properties of which are well known. However, little is known about the characteristics of ameloblasts themselves or about the functions of amelogenins. In this study, we developed a novel primary and secondary culture system for ameloblasts using a monoclonal antibody which recognized amelogenin (En3). The cell layer on dentine removed from rat mandibular incisors was isolated and cultured in low calcium, serum-free medium. Primary culture was performed on collagen-coated culture plates and typically, two types of cells appeared. One major type changed morphology after the addition of a high concentration of calcium to the medium. Expression of amelogenin was shown as cytoplasmic particles in these cells using En3. In the secondary culture, expression of amelogenins was also observed. In this system, the cells grew and maintained the expression of amelogenin for about 3 weeks.

Ameloblasts↗

PubMed1992

Heterogeneous distribution of the precursor of type I and type III collagen and fibronectin in the rough endoplasmic reticulum of palatal mesenchymal cells of the mouse embryo cultured in ascorbate-depleted medium.

In order to examine the intracellular distribution of precursors of type I and type III collagen and fibronectin in the palatal mesenchymal (MEPM) cells of the mouse embryo cultured under ascorbate-deficient conditions, immuno-electron-microscopic studies were carried out by use of affinity purified antibodies for these proteins. MEPM cells were obtained from the palatal shelves of 14-day-old mouse fetuses and cultured for 3-7 days in medium, either with or without 50 ng/dish/day ascorbic acid. Results obtained were as follows: (1) Although the rough endoplasmic reticulum (rER) of MEPM cells cultured for 5 days in ascorbate-supplemented medium was flattened, that in cells cultured in ascorbate-deficient medium had a distended or vesicular appearance. (2) Vesicular or distended rER showed heterogeneous staining for both type I and type III collagen, namely, some parts of rER showed positive staining for both types of collagen, while others showed negative staining. (3) Both type I and type III collagen showed codistribution in the same vesicular rER. (4) Vesicular rER showed negative or very faint labelling for fibronectin. These results may suggest regional differences in the function of rER.

Animals↗

PubMed1992

Penetration of etoposide into human malignant brain tumors after intravenous and oral administration.

Penetration of etoposide into the cerebrospinal fluid, brain tumor, and brain tissue after intravenous administration was investigated in patients presenting with malignant brain tumors. A relatively low dose (55-65 mg/m2) was used to compare intravenous with oral administration. High-performance liquid chromatography with fluorescence detection was used to evaluate drug levels. Plasma and cerebrospinal fluid levels of etoposide after oral administration (50-150 mg/day) were also studied so as to determine the adequate oral dose for the treatment of malignant brain tumors. The peak plasma concentration after intravenous administration ranged from 7.01 to 10.47 micrograms/ml, varying in proportion to the injected dose, whereas that after oral administration was lower, namely, 1.44-4.99 micrograms/ml, and was unstable when the oral dose was 150 mg daily. The peak cerebrospinal fluid level following either intravenous or oral administration was much lower than the plasma concentration and was influenced by the peak plasma level and the sampling site. The etoposide concentration in cerebrospinal fluid taken from the subarachnoid space and ventricle of patients displaying no tumor invasion and of those presenting with meningeal carcinomatosis and in cerebrospinal fluid taken from the dead space after tumor resection was 0.7% +/- 0.5%, 3.4% +/- 1.0%, and 7.2% +/- 8.5%, respectively, of the plasma concentration. Serial oral administration did not result in the accumulation of etoposide in cerebrospinal fluid. The tumor concentration (1.04-4.80 micrograms/g) was 14.0% +/- 2.9% of the plasma level after intravenous administration, was related to the injected dose, and was approximately twice the concentration detected in the brain tissue. Therefore, a relatively low dose of etoposide injected intravenously penetrates the brain tumor at an efficacious concentration. Our results indicate than an oral dose of 100 mg etoposide be given for malignant brain tumors, as limited penetration of the drug into the intracranial region was observed.

Administration, Oral↗

PubMed1992

Intracranial germ-cell tumor with synchronous lesions in the pineal and suprasellar regions: report of six cases and review of the literature.

The features of intracranial germ-cell tumor with synchronous lesions in the pineal and suprasellar regions (GCTSPS) in six patients were investigated. GCTSPS accounted for 12.8% of all germ-cell tumors (GCT) in our brain tumor study group. In all cases, the initial symptoms were attributable to the suprasellar lesion, and symptoms due to the pineal GCT developed only after admission. Five of the six cases were histologically diagnosed as germinoma. In all cases, tumors of both regions disappeared after irradiation, resulting in no recurrence for an average of 55.3 months. Our experience and reports in the literature suggest that GCTSPS is highly sensitive to radiation in most cases, although some reports indicated that recurrence is frequent after radiation therapy alone. It is suggested that histological diagnosis in one of the GCTSPS lesions is undertaken to make a plan for the following treatment.

Adolescent↗

PubMed1992

Intracranial metastasis from a spinal cord primitive neuroectodermal tumor: case report.

A patient with intracranial seeding from a spinal cord primitive neuroectodermal tumor with ependymal differentiation is presented. The first and second stages of intracranial dissemination were well controlled by a combination of irradiation and chemotherapy. The authors review previously published cases and discuss the possible mechanism of seeding from the spinal cord to the intracranial region.

Adolescent↗

PubMed1992

Transcranial Doppler sonography in carotid-cavernous fistulas: analysis of five cases.

Transcranial doppler sonography was performed transorbitally in five patients clinically diagnosed as unilateral carotid-cavernous fistula. Dural arteriovenous malformation related-shunts were detected in all the patients. In the normal eyes, the only doppler signals observed at an insonation depth of 45 to 55 mm were those of the ophthalmic artery. In the affected eyes, abnormal doppler signals with relatively higher flow velocity and lower resistance were observed. In three of the cases, these abnormal signals showed a flow directed anteriorly or away from the cavernous sinus, consistent with changes in the ophthalmic veins caused by the presence of the shunts. In two cases, however, the observed flows were directed posteriorly, the normal direction of these veins. The possible explanations for this discrepancy are discussed in relation with angiographic findings. The use of transcranial doppler might provide a better understanding about hemodynamic changes in carotid cavernous fistulas.

Aged↗

PubMed1992

Recombinant LD78 protein, a member of the small cytokine family, enhances osteoclast differentiation in rat bone marrow culture system.

Cytokine LD78 is a member of the small inducible protein family involved in cell growth, wound healing and inflammation. However, its exact function is not known. In this study, we demonstrated that recombinant LD78 alpha and its variant LD78 beta proteins stimulate osteoclast-like cell formation in rat bone marrow cultures in the presence of 1 alpha, 25-dihydroxyvitamin D3. This enhancing activity was independent of prostaglandin synthesis. This is the first report which describes the effect of proteins involved in the small inducible protein family on the differentiation of osteoclasts.

Animals↗

PubMed1992

Trypsinized osteoclast-like multinucleated cells formed in rat bone marrow cultures efficiently form resorption lacunae on dentine.

Rat bone marrow cultures containing 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] formed multinucleated cells (MNCs) that had many characteristics of osteoclasts. These MNCs, which have a tartrate-resistant acid phosphatase (TRAP) activity, could be classified into two morphological types: one type had smooth cellular margins (smooth-margined MNCs) and the other type had irregular spike-like margins (stellate MNCs). When bone marrow cells depleted of authentic osteoclasts were seeded and cultured on dentine slices, only low numbers of resorption lacunae could be detected. However, when preformed MNCs were detached by trypsinization and replated on dentine slices, numerous resorption lacunae were observed by scanning electron microscopy on these slices. Formation of lacunae occurred reproducibly during the five to ten days of culture. We also examined the effect of retinoic acid on TRAP-positive MNC formation in this bone marrow culture system. Although RA inhibited total TRAP-positive MNC formation, it increased the ratio of stellate MNCs to smooth-margined MNC, suggesting that RA may have the ability to regulate the formation of active osteoclasts.

Animals↗

PubMed1992

Demonstration of type III collagen in the dentin of mice.

It has been reported that, although type III collagen is present in human dentin where there is dentinogenesis imperfecta and in reparative dentin, it is absent in normal dentin. In a preliminary study, however, we observed evidence showing that small amounts of fibers showing positive labeling for type III collagen are present in the molars of normal mice. In the present study, in order to localize type III in normal dentin, immunofluorescent and immunoelectron microscopic examinations of the molars of normal mice were carried out using affinity-purified antibodies to mouse type III and type I collagen. The fibers positive for type III collagen were much more frequently observed in the root than in the crown. These fibers ran in peritubular dentin or near that in parallel to them. The incidence of the existence of dentinal tubules associated with type III collagen-positive fibrils either in or near peritubular dentin was low. These fibrils positive for type III collagen showed a clear cross-banding. In dentinal tubules, unusual collagen aggregations, segment long-spacing-like and fibrous long-spacing-like structures which were intensively stained for type I collagen but weakly so for type III collagen were seldom observed. Type III collagen-positive fibers often extended towards the pulp beyond the odontoblast layer, suggesting that these fibers were produced, at least partly, by the pulp cells.

Animals↗

PubMed1992

Effects of diltiazem and noradrenaline on extracellular potassium changes in the globally ischaemic rat heart.

OBJECTIVE: The aim was to investigate the effects of a calcium antagonist (diltiazem) and a catecholamine (noradrenaline) on extracellular potassium accumulation during global ischaemia. METHODS: Extracellular potassium concentration ([K+]e) was measured during 30 min global ischaemia in the isolated rat heart using a valinomycin potassium sensitive electrode. Contracture development during ischaemia was measured throughout with an intraventricular balloon inserted into the left ventricle and myocardial adenine nucleotides were measured in separate series of hearts. RESULTS: In control hearts, [K+]e showed a characteristic triphasic change during 30 min global ischaemia. This consisted of an early rising phase followed by a transient falling phase after the initial peak of [K+]e, and then a late rising phase. Diltiazem suppressed the rate of rise of [K+]e during early ischaemia, but extended the time course of the early [K+]e rise with the higher dose, abolishing the transient falling phase of [K+]e. During late ischaemia, the rise in [K+]e was attenuated by diltiazem. Noradrenaline also suppressed the early extracellular potassium accumulation, but in contrast to diltiazem, hastened the time course of the late [K+]e rise. CONCLUSIONS: Although diltiazem suppresses the early potassium loss during ischaemia as previously described, the drug also decreases the [K+]e fall by some as yet unknown mechanism, so that the [K+]e level becomes higher than control during the falling phase.

Adenosine Triphosphate↗

PubMed1992

Distribution of calcitonin gene-related peptide and substance P-immunoreactive nerve fibers and their correlation in the periodontal ligament of the mouse incisor.

The distribution of calcitonin gene-related peptide (CGRP)- and substance P (SP)-immunoreactive (IR) nerve fibers and their correlation in the periodontal ligament of mouse incisors were examined by indirect immunofluorescence. Both CGRP-IR and SP-IR thin nerve fibers were abundant in the apical and middle third of the periodontal ligament. In the lingual portion of the incisal periodontal ligament, these nerve fibers were localized in the alveolar half of the periodontal ligament and were observed as free nerve endings. No CGRP-IR and SP-IR specialized nerve endings, such as Ruffini-like corpuscles, were observed. In the labial periodontal ligament, CGRP-IR and SP-IR nerve fibers ran along the incisal axis. The distribution of CGRP-IR nerve fibers was very similar to that of SP-IR nerve fibers.

Animals↗

PubMed1992

12-O-tetradecanoylphorbol-13-acetate inhibits osteoclast-like cell differentiation in rat bone marrow cultures by inducing macrophage polykaryons.

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) at 10(-9) M stimulated the formation of osteoclast-like multinucleated cells (MNCs) in the presence of 1 alpha,25-dihydroxyvitamin D3 in rat bone marrow cultures. However, at 10(-7) M, it clearly inhibited 1 alpha,25-dihydroxyvitamin D3-dependent osteoclast-like MNC formation at 6 days of culture. In cultures treated with 10(-7) M TPA, numerous MNCs that lack the marker enzyme tartrate-resistant acid phosphatase (TRAP) were formed. These TRAP-negative MNCs had neither receptors for calcitonin nor dentine-resorbing activity. The reactivity of the cells against antirat macrophage antibodies was completely different from that of authentic osteoclasts. These data suggest that TRAP-negative MNCs formed in the presence of 10(-7) M TPA are macrophage polykaryons. Time-course studies showed that 10(-7) M TPA stimulated osteoclast-like MNC formation at 4 days of culture, but these osteoclast-like MNCs were converted to TRAP-negative MNCs. Furthermore, 1-(5-isoquinolinyl-sulfonyl)2-methylpiperazine (H-7), a protein kinase-C inhibitor, inhibited osteoclast-like MNC formation in a dose-dependent fashion. These results suggest that activation of protein kinase-C may play a role in osteoclast differentiation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1992

Microprolactinoma invading the cavernous sinus--report of three cases.

Three cases of microprolactinoma with cavernous sinus invasion on magnetic resonance imaging are reported. High-resolution computed tomographic scans did not demonstrate the cavernous sinus involvement. Magnetic resonance imaging is indispensable to detect cavernous sinus invasion before treatment (transsphenoidal surgery or bromocriptine treatment) of a microprolactinoma.

Adult↗

PubMed1992

Clinical effect of intra-arterial tumor necrosis factor-alpha for malignant glioma.

Recombinant human tumor necrosis factor-alpha was administered intra-arterially to treat 20 cases of malignant gliomas, mostly progressive or recurrent. The optimum dosage was determined to be 1 x 10(5) U/sq m/day. Among the 10 evaluable patients treated at this dosage, two responded (one completely and one partially), resulting in a 20% response rate. Side effects were mild and easily controllable. Improvement of neurological symptoms was noted in 47% of the patients a few days after treatment, even when computerized tomography showed no tumor regression. This might have been due to the pleiotypic biological activity of tumor necrosis factor-alpha. Neuroradiographic observations revealed narrowing of the tumor-feeding artery, a decrease in tumor staining ability, and necrosis in the central part of a tumor. The authors suggest that intra-arterial administration of tumor necrosis factor-alpha may be an effective treatment for malignant glioma, including recurrent cases.

Adolescent↗

PubMed1992

[Single-dose captopril test and captopril renal scintigraphy in the evaluation of renovascular hypertension].

The effectiveness of single-dose captopril test (CP-T) and captopril renal scintigraphy with 99mTc-DTPA (CP-RG) in the diagnosis of renovascular hypertension (RVH) was evaluated in 27 patients with (Group I, 16 patients) or without (Group II, 11 patients) renal vascular disease. Group I consisted of RVH in 8 patients (bilateral in 3, unilateral in 5), arteriovenous malformation in 3, renal artery aneurysm in 4, including 2 with essential hypertension, and asymptomatic renal artery stenosis in 1. Group II consisted of 6 hypertensive patients (2 with essential hypertension and 4 with renal hypertension) and 5 normotensive patients. Sensitivity of CP-T and CP-RG in the diagnosis of RVH was 29% (2/7) and 86% (6/7), respectively, indicating the latter was more sensitive than the former. In 3 patients with bilateral RVH, positive response in CP-RG was observed only in the unilateral kidney. Specificity of CP-T and CP-RG was 86% (6/7) and 100% (5/5), respectively in Group I, 100% (8/8) and 83% (5/6), respectively in 16 hypertensive patients. CP-T and CP-RG before and after the treatment of RVH were evaluated in 4 patients. The change of positive response in CP-T and CP-RG into negative after percutaneous transluminal renal angioplasty (PTA) or surgery were found in 3, all followed by a fall in blood pressure, which was not observed in the other patient with positive response after PTA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

[Pineocytomas; clinicopathological evaluation of 4 cases].

Clinicopathological evaluation of pineocytoma was performed in 4 patients. The subjects, 2 males and 2 females, ranged in age from 17 to 40. All the patients were clinically found to have the symptom of increased intracranial pressure on a monthly basis, but none of them were found to have dorsal midbrain dysfunction symptoms such as Parinaud's sign or Argyll Robertson pupil. Diagnostic imaging produced heterogeneous pictures indicating calcifications and cyst in 2 patients and homogeneous pictures of the tumor parenchyma in the other 2 patients. Histologically, the former cases were found to have many pineal-sand-like calcifications. Median sagittal MR images demonstrated expansive growth of pineocytoma. Quadrigeminal plates which kept their shapes were observed in 2 patients. Craniotomy was performed in all cases, removing the tumor totally in 2 patients. Radiation therapy was given to 3 patients, resulting in complete remission, but radiosensitivity varied according to cases. During the follow-up period of 12 to 42 months, one patient died of peritonitis caused by shunt infection. No recurrence of the tumor was seen in any of the patients. The incidence of pineocytoma was very low. Further evaluation of the tumor involving many cases is advisable.

Adolescent↗

PubMed1991

Glutathione and cellular response of ACNU-resistant rat glioma sublines to drugs and radiation.

Three ACNU-resistant sublines (R1, R3 and R12) from rat glioma 9L cells showed cross-resistance to vinblastine, adriamycin, and VP-16. Among these, the R3 subline also acquired radioresistance under aerobic conditions. Total glutathione levels in these sublines were elevated 2- to 3-fold. Treatment of the cells with BSO, a specific inhibitor of GSH synthesis, resulted in decreased intracellular total glutathione levels in all 4 cell lines to about 10% of control levels. However, sensitivity to radiation or to chemicals did not change accordingly. Treatment of 9L cells with OTZ, a precursor of cysteine, resulted in a rise in intracellular GSH levels but it did not correlate with sensitivity to X-ray or to ACNU. These results suggest that, in terms of cellular sensitivity to radiation or ACNU, total glutathione level alone cannot serve as a predictive indicator.

Animals↗