Biomedical subjects

R Tanaka

Publications and source records attributed to R Tanaka.

At least 181 records · Page 10Linked to original sources

PubMed1999

Survival of a probiotic, Lactobacillus casei strain Shirota, in the gastrointestinal tract: selective isolation from faeces and identification using monoclonal antibodies.

Lactobacillus casei strain Shirota (LCS) is a probiotic bacterium used in the production of fermented milk products and lactic acid bacteria preparations. To investigate the survival of LCS in the gastrointestinal tract, we have developed a selective medium and specific monoclonal antibodies to isolate and identify this strain. Selective LLV agar medium was prepared by modifying LBS medium, a selective medium for lactobacilli, through the replacement of glucose with lactitol as a carbon source and vancomycin as a selective antibiotic. Culture in LLV agar medium followed by ELISA using monoclonal antibodies specific for LCS was able to detect the organism in faeces. Using this method, we studied the faecal recovery of LCS in individuals who drank 125 ml of fermented milk which contained 10(10) live LCS for 3 days. The mean recovery was about 10(7) live bacteria per gram of faeces, indicating that LCS survived transit through the gastrointestinal tract after ingestion of the fermented milk.

Adult↗

PubMed1999

Patients with temporal lobe epilepsy show an increase in brain-derived neurotrophic factor protein and its correlation with neuropeptide Y.

Model studies on animal seizures have proposed potential involvement of the neurotrophins, BDNF and NGF, in human epilepsy. However, their biological significance in this disease itself remains to be evaluated. Here we demonstrate that patients with intractable temporal lobe epilepsy show a marked increase in protein levels of BDNF (2.6-fold, p<0.01) but not other neurotrophins. Moreover, the specific BDNF increase was significantly correlated with contents of neuropeptide Y. Thus, these results indicate the activity-dependent expression of BDNF in human subjects and its potential contribution to the pathophysiology of human epilepsy via neuropeptide Y.

Adolescent↗

PubMed1999

Intracranial malignant lymphomas: clinicopathological study of 26 autopsy cases.

We examined 26 autopsy-proven cases of intracranial malignant lymphoma (IML) in immunocompetent patients to determine the extent of neoplastic involvement of the central nervous system (CNS) and to evaluate the effects of radiation on the tumor and brain tissue. All tumors were identified as diffuse non-Hodgkin's lymphomas of B-cell origin. In six patients who had not received radiotherapy, the clinical course of the disease was short and extensive infiltration of the tumor was seen. The remaining 20 patients were treated with radiotherapy and had a longer survival time. Leptomeningeal involvement was common, but extensive subarachnoid proliferation of the tumor was seen in only two cases. The posterior, but not anterior, lobe of the pituitary was involved in 5 of 22 cases, and choroid plexus involvement was seen in 4 of 21. Direct invasion of the tumor into the spinal cord, which tended to occur in patients with posterior fossa masses, was observed in 5 of 21 cases. Following irradiation, coagulation necrosis was frequently found in the invading zone as well as in the tumor mass, and degeneration of the white matter was also seen. We suggest that IML can extensively infiltrate into the CNS, including the posterior lobe of the pituitary and spinal cord, and that radiation injury to the brain appears to occur relatively easily in this disease.

Adult↗

PubMed1999

Clinicopathological study of pineal parenchymal tumors: correlation between histopathological features, proliferative potential, and prognosis.

This study describes the clinicopathologic features of 13 cases with pineal parenchymal tumors. Based on the histopathologic findings, especially the extent of atypia and pineocytic differentiation as determined by Bodian's staining, we classified these tumors into pineocytomas (4), pineocytomas with anaplasia (4) and pineoblastomas (5). All the cases with pineocytoma and pineocytoma with anaplasia were adults, and all the cases with pineoblastoma were younger children. One patient with pineocytoma died of other disease 7 months after initial treatment. One patient with pineocytoma with anaplasia died 168 months after initial treatment. The other patients with pineocytoma and pineocytoma with anaplasia survived between 9 and 179 months after surgery. However, all of the five pineoblastoma patients died within 14 months after initial treatment. The mean MIB-1 index in pineoblastomas was significantly higher than that in other types of pineal parenchymal tumors, but there were no differences between pineocytomas and pineocytomas with anaplasia with respect to the MIB-1 index. The mean MIB-1 index in neurofilament protein-immunopositive cases was significantly lower than that in immunonegative cases. With regard to the malignant potential, we emphasize that a clear distinction should be made between pineoblastomas in children and other types of pineal parenchymal tumors in adults.

Adult↗

PubMed1999

A noninvasive method of measuring wave intensity, a new hemodynamic index: application to the carotid artery in patients with mitral regurgitation before and after surgery.

Wave intensity (WI) is a new hemodynamic index, which is defined as (dP/dt)(dU/dt) at any site of the circulation, where dP/dt and dU/dt are the time derivatives of blood pressure and velocity, respectively. Arterial WI in normal subjects has two positive sharp peaks. The first peak occurs during early systole when a forward-traveling compression wave is generated by the left ventricle. The magnitude of this peak increases markedly with an increase in cardiac contractility. The second peak, which occurs towards the end of systole, is caused by generation of a forward-traveling expansion wave by the ability of the left ventricle to actively stop aortic blood flow. The interval between the R wave of the ECG and the first peak of WI (R-1st peak interval) and the interval between the first and second peaks (1st-2nd interval) are approximately equal to the preejection period and left ventricular ejection time, respectively. Using a combined Doppler and echo-tracking system, we obtained carotid arterial WI noninvasively. We examined the characteristics of WI in 11 patients with mitral regurgitation (MR) before and after surgery, and 24 normal volunteers. In the MR group before surgery, the second peak was decreased and the (1st-2nd interval)/(R-R interval) ratio was reduced, compared with the normal group (140 +/- 130 vs 750 +/- 290mmHg m/s3. P < 0.0083; 20.7% +/- 3.4% vs 26.7% +/- 2.8%, P < 0.083). There were no significant differences in the first peak between the normal group and the MR group before and after surgery. The second peak in the MR group was increased significantly (P < 0.016 vs before surgery) to 1,150 +/- 830mmHg m/s3 in the early period after surgery (stage I), and to 1,090 +/- 580mmHgm/s3 in the late period after surgery (stage II). These values did not differ significantly from that of the normal group. At stage I, the (R-1st peak interval)/ (R-R interval) ratio was increased from 13.4% +/- 2.7% to 20.6% +/- 5.6% (P < 0.016 vs before surgery). At stage II, this ratio decreased to 16.2% +/- 2.8% (P < 0.016 vs stage I). but was still significantly higher than that before surgery. The (1st-2nd interval)/(R-R interval) ratio increased significantly after surgery (P < 0.016 vs before surgery) to values (27.0% +/- 4.5% at stage I and 28.9% +/- 2.6% at stage II) which did not differ significantly from that of the normal group. The recovery of the second peak after surgery suggests that the left ventricle had recovered the ability to actively stop aortic blood flow. Wave intensity is useful for analyzing changes in the working condition of the heart.

Adult↗

PubMed1999

The factors influencing haematoma volume due to arteriovenous malformations.

Haemorrhage due to cerebral arteriovenous malformations (AVMs) varies from massive, requiring urgent operations, to clinically silent. The present study was designated to identify factors influencing haematoma size, and the pathophysiological mechanisms of massive haemorrhage were studied. 55 patients with intracerebral haematomas due to supratentorial AVMs were included in this study. Angiographic and clinical findings were retrospectively evaluated in relation to haematoma size. Statistical analysis demonstrated that small size and the presence of only one draining vein were high risk factors for massive haemorrhage. The haematoma volume in small AVMs (30 +/- 4 cm3) was significantly larger than in other AVMs (7 +/- 3 cm3) (p = 0.0005). AVMs with only one draining vein were associated with massive haematoma volume as compared to AVMs with two or more draining veins (30 +/- 4 versus 11 +/- 3 cm3, p = 0.0023). Our previous study demonstrated that feeding artery pressure (FAP) was significantly higher in AVMs with haemorrhage than in those without, as was draining vein pressure (DVP), and FAP and DVP were inversely related to the number of draining veins and the size of the AVMs. Thus, in small AVMs and AVMs with only one draining vein, local increase in DVP may thus contribute to massive haemorrhage.

Arteriovenous Malformations↗

PubMed1999

Inhibition of experimental bone resorption and osteoclast formation and survival by 2-aminoethanesulphonic acid.

It is known that bone resorption is mediated by osteoclasts, and lipopolysaccharide (LPS) and inflammatory mediators such as interleukin-1 (IL-1) and prostaglandin E2 (PGE2) induce osteoclast differentiation from haemopoietic cells, 2-aminoethanesulphonic acid, which is known as taurine, is an important nutrient and is added to most synthetic human infant milk formulas. In this study, it was found that 2-aminoethanesulphonic acid inhibits the stimulation of bone resorption mediated by LPS of the periodontopathic microorganism Actinobacillus actinomycetemcomitans Y4 in organ cultures of newborn mouse calvaria. The effect of 2-aminoethanesulphonic acid on the development and survival of osteoclast-like multinucleated cells produced in a mouse bone-marrow culture system was also examined. 2-aminoethanesulphonic acid (100 microg/ml) suppressed the formation of these osteoclast-like cells in the presence of LPS of A. actinomycetemcomitans Y4, IL-1alpha or PGE2 in mouse marrow cultures. On the other hand, 2-aminoethanesulphonic acid did not inhibit 1alpha, 25-dihydroxyvitamin D3-mediated osteoclast differentiation. Although IL-1alpha elongated the survival of the osteoclast-like cells, 2-aminoethanesulphonic acid blocked the supportive effect of IL-1alpha on osteoclast survival. 2-aminoethanesulphonic acid showed no effect on the growth of mouse osteoblasts. Finally, it was found that 2-aminoethanesulphonic acid inhibited alveolar bone resorption in experimental periodontitis in hamsters. These results suggest that 2-aminoethanesulphonic acid is an effective agent in preventing inflammatory bone resorption in periodontal diseases.

Aggregatibacter actinomycetemcomitans↗

PubMed1999

Role of platelet-activating factor acetylhydrolase gene mutation in Japanese childhood IgA nephropathy.

Platelet-activating factor (PAF) is a potent mediator of inflammatory injury in renal diseases. PAF is degraded to inactive products by PAF acetylhydrolase. Recently, a point mutation (G to T transversion) of the PAF acetylhydrolase gene was observed at position 994, and this mutation was found to contribute to the variability in plasma PAF levels, with undetectable plasma PAF acetylhydrolase activity occurring in homozygous patients (TT genotype) and reduced levels of activity in heterozygous patients (GT genotype). Therefore, we investigated the effect of the PAF acetylhydrolase gene mutation on the pathogenesis and progression of immunoglobulin A (IgA) nephropathy. Genomic DNA was obtained from 89 children with IgA nephropathy and 100 controls. We identified the PAF acetylhydrolase gene mutation (G994T) by polymerase chain reaction. There was no significant difference in genotypic frequency between patients and controls. However, urinary protein excretion at the time of biopsy was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. The percentage of glomeruli with mesangial cell proliferation was significantly greater in patients with the GT/TT genotypes than in those with the GG genotype. These results indicate the PAF acetylhydrolase gene mutation may influence the degree of proteinuria and the extent of mesangial proliferation in the early stage of childhood IgA nephropathy.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed1999

The effect of muscle-tone-reducing procedures in athetotic head movements: partial nerve block by lidocaine and surgical release of the neck muscles.

OBJECTIVE: To investigate the effect of muscle-tone-reducing procedures (MTRPs), i.e. partial nerve block by lidocaine (PNB) and surgical release of muscle attachment to bone (SRMAB), on incessant involuntary head movements in athetotic patients. METHODS: Pre/post-MTRP changes in neck-muscle activities, glabella movement and maximum isometric forces of the head were measured in six athetotic patients with severe spondylotic myelopathy resulting from incessant involuntary head movements. RESULTS: Pre/post-MTRP changes in neck-muscle activities resembled those after gamma-block. In four patients, PNB reduced the maximum isometric force by no more than 40% of pre-PNB force, while decreasing the amount of involuntary head movements to 37-65% of the pre-PNB value in the frontal plane. MRSAB reduced the force by less than 40% of pre-SRMAB force in 4 MRSAB tested patients, while decreasing the amount of involuntary head movements to 12-45% of the pre-SRMAB value in all 6 patients. CONCLUSION: MTRPs reduced involuntary head movements significantly while preserving voluntary muscle forces relatively well. PNB and SRMAB procedures have in common the effect of reducing gain in the myotatic reflex pathway by decreasing the excitatory inflows to alpha-motoneurons via muscle spindle Ia-afferents, which resulted from blocking mainly gamma-efferent conduction by PNB, and reducing background tension in muscle spindles by SRMAB.

Adult↗

PubMed1999

Two novel lanostane-type triterpenes from the stem bark of abies mariesii

Two novel lanostane-type triterpene lactones, 3alpha, 11alpha-dihydroxy-7-oxolanosta-8,24-dien-26,23(R)-olide (1) and 1alpha,3alpha,11alpha-trihydroxy-7-oxolanosta-8,24-dien-26, 23(R)-olide (2), were isolated from the stem bark of Abies mariesii, together with a known triterpene, 3-oxo-9betaH-lanosta-7,24-dien-26, 23(R)-olide. The structures of 1 and 2 were determined on the basis of 2D NMR techniques.

Journal Article↗

PubMed1999

Establishment of two glioma cell lines from two surgical specimens obtained at different times from the same individual.

We established two glioma cell lines from two surgical specimens obtained at different times from the same patient. One (No. 9R), which was derived from the recurrent tumor (glioblastoma, grade IV), proliferated more rapidly in vitro than the other (No. 9) from the primary tumor (slightly anaplastic astrocytoma, grade II-III). No. 9R showed heterotransplantability in nude mice, whereas No. 9 did not. These findings indicate that No. 9R has a more aggressive or malignant nature than No. 9. Both cell lines showed homozygous deletion of the representative tumor suppressor p16 and p15 genes, but no p53 gene alteration. However, examination of the overall mRNA expression profile using a commercially available cDNA-spotted membrane revealed much higher expression levels of several mRNAs, at least, in No. 9R than in No. 9, although the relationship between these mRNAs and the growth potentials remained unknown. These two cell lines, derived from the same individual, with different proliferating potentials may be useful for studies on the molecular bases of glioma malignancy and progression.

Animals↗

PubMed1999

Suppression of TGF-beta1 in human gliomas by retroviral gene transfection enhances susceptibility to LAK cells.

Human glioma cell line, Onda 10 produces TGF-beta1. TGF-beta1 has a biological role for the immunosuppression of the host. We have investigated whether suppression of TGF-beta1 on human glioma cell enhanced the susceptibility to lymphokine-activated killer (LAK) cells. In vitro, susceptibility to LAK cells on Onda 10 cell is augmented by retroviral gene transfection with antisense TGF-beta1. Nude mice bearing Onda 10 cells transduced with antisense TGF-beta1 gene has a longer life span compared to mice carrying that of sense TGF-beta1 gene or vector alone. The cytotoxic activity of LAK cells induced from spleen cells of mice carrying antisense TGF-beta1 gene transduced cells is higher against Onda 10 cell than that of LAK cells from mice carrying vector alone transduced cells. Also, antisense TGF-beta1 gene transduced cells are much more sensitive to LAK cells compared to Onda 10. These suggest that the augmented host systemic immunity in mice is one of the mechanisms of the reduced tumorigenicity of antisense TGF-beta1 gene transduced cells and that the increased systemic immunity could be ascribed to the increased immunogenicity of the tumor cells. The gene therapy for malignant glioma with antisense TGF-beta1 gene is expected to be promising.

Animals↗

PubMed1999

The relationship between modified pulse wave transit time and cardiovascular changes in isoflurane anesthetized dogs.

OBJECTIVE: To clarify the relationship between blood pressure and pulse wave transit time at the peripheral artery from the R wave of the electrocardiogram (m-PWTT), the effects of cardiovascular interventions on this relationship was evaluated. METHODS: Ten mongrel dogs were anesthetized by isoflurane inhalation, and catheter tip pressure transducers were inserted into the ascending aorta and at the bifurcation of abdominal aorta to measure central and peripheral pulse wave arrival. Pulse wave arrival at the ascending aorta from the R wave represents pre-ejection period (PEP) and pulse wave arrival between the ascending aorta and bifurcation of aorta represents pulse wave transit time (PWTT), thus m-PWTT = PEP + PWTT. Hypertension was induced by the continuous infusion of dobutamine and phenylephrine, and hypotension was induced by deepening isoflurane anesthesia, acute blood loss and nitroglycerine infusion. The relationship between timing components (PWTT, PEP, and m-PWTT) and blood pressure was recorded and analyzed by using the least squares method. RESULTS: The relationship between timing components (PWTT, PEP and, m-PWTT) and blood pressure was significant and highly correlated. When the change in blood pressure was due to the myocardial contractility, such as after dobutamine infusion, the relationship between all timing components and blood pressure was consistent and negative. However, when the change in blood pressure was due to the vasoactive agents, such as phenylephrine, the relationship between timing components and blood pressure was dependent on the reflex change in PEP. CONCLUSIONS: Change in m-PWTT is a good parameter to predict blood pressure changes, although the absolute blood pressure value cannot be obtained.

Anesthetics, Inhalation↗

PubMed1999

Anti-tumor-promoting rearranged abietane diterpenes from the leaves of Larix kaempferi.

Two novel rearranged abietane-type diterpene acids, karamatsuic acid (1) and larikaempferic acid (2) were isolated as their corresponding methyl esters, 1a and 2a, from the leaves of Larix kaempferi (Lamb.) Carr. Their structures were established as 9,10 alpha-epoxy-9,10-seco-abieta-8,11,13-trien-18-oic acid and 9 alpha,13 alpha-epoxy-8-oxo-9(8-->7)abeo-7 beta H-abietan-18-oic acid, respectively, by spectral evidence. Compounds 1a, 2a and 12,15-dihydroxydehydroabietic acid (3) exhibited potent inhibitory effects against 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced Epstein-Barr virus early antigen (EBV-EA) activation in Raji cells.

Animals↗

PubMed1999

Vascular endothelial growth factor-C gene expression in papillary and follicular thyroid carcinomas.

BACKGROUND: Vascular endothelial growth factor-C (VEGF-C) is known to be related to development of lymphatic vessels. Papillary thyroid carcinoma characteristically metastasizes to regional lymph nodes, whereas follicular thyroid carcinoma commonly spreads hematogenously. The present study was designed to determine whether expression of the VEGF-C gene is related to the different metastatic features of these 2 types of thyroid carcinoma. METHODS: Thyroid carcinoma specimens were obtained from 15 patients with papillary carcinoma and 4 patients with follicular carcinoma of the thyroid. VEGF-C gene expression was examined by Northern blotting and in situ hybridization. Immunohistochemistry was performed to localize the deposition of VEGF-C protein. RESULTS: The ratios of VEGF-C gene expression determined by Northern blot analysis were significantly higher in papillary than in follicular carcinoma. Nonmalignant thyroid tissue from patients with papillary carcinoma also expressed higher levels of VEGF-C than tissue from patients with follicular carcinoma. Expression of the VEGF-C gene was observed by in situ hybridization in cells of papillary thyroid carcinoma but not in those of follicular carcinoma. Positive staining with antibody against VEGF-C was detected in papillary cancer cells. CONCLUSIONS: Concurrent overexpression of the VEGF-C gene by both tumor cells and the surrounding tissue may be related to the prevalence of intrathyroidal spread through lymphatics and regional lymph node metastasis in patients with papillary thyroid carcinoma.

Adenocarcinoma, Follicular↗

PubMed1999

Spontaneous carotid cavernous fistulas with special reference to the influence of estradiol decrease.

The etiology of the dural arteriovenous fistula (AVF) involving the cavernous sinus is still unknown. However, it is of interest that this condition usually occurs in post-menopausal women. The purpose of the present study was therefore to clarify the relationship between sex hormone blood levels and the occurrence of dural AVFs in the cavernous sinus. Serum sex hormone levels and factors associated with atherosclerosis were examined in 26 consecutive patients with dural AVF involving the cavernous sinus presenting at our institute during the last eight years and compared with those of a post-menopause control group. Of the present patient series, 21 (81%) were women. All except five had passed menopause. Five (24%) of the women patients presented with symptoms consistent with cessation of menstruation, namely, a blood level of estradiol significantly lower than the control value. Hypertension was recognized in 10 (71%) of 14 females who had experienced menopause 10 or more years previously and in all male patients. A sudden abnormal decrease of blood estradiol levels in female patients demonstrating symptoms consistent with menopause may thus be an important precipitating factor in the occurrence of dural AVFs involving the cavernous sinus. Hypertension, in older female and male patients, with or without longstanding low blood estradiol levels, may cause atherosclerosis of the feeding vessels in the dura mater, resulting in the opening of a normal AV shunt to provide collateral circulation.

Aged↗

PubMed1999

Phosphorothioate G3T4G3 motifs inhibits the early stage of HIV-1 infection.

It is well known that G-rich phosphorothioate oligonucleotides (G-rich PS) bind to the V3 loop of HIV-1 gp120 and inhibit HIV-1 infection. In this study, we investigated the inhibitory mechanism of a new type of G-rich PS (PS-G3T4G3) on the replication cycle of HIV-1. PS-G3T4G3 inhibits both cell to cell and cell free infections. Binding and entry assays revealed that the inhibitory step of PS-G3T4G3 occurs at the early stage of HIV-1 infection. V3 loop-specific mAb test showed that PS-G3T4G3 binds to the V3 loop and prevents its interaction with chemokine receptors. These results suggest that PS-G3T4G3 may be a novel candidate for an HIV-1 inhibitor.

Base Composition↗

PubMed1999

Effects of OK-432 on the proliferation and cytotoxicity of lymphokine-activated killer (LAK) cells.

We studied the effect of a streptococcal preparation, OK-432, on the cytotoxicity and the proliferation of lymphokine-activated killer (LAK) cells for use in adoptive immunotherapy. Peripheral blood mononuclear cells (PBMC) were derived from healthy donors and patients with malignant brain tumors. We divided PBMC into two groups; these cells then were stimulated with interleukin-2 in the presence or absence of OK-432. OK-432 was added only in the initial 3 days during the 3-week midterm culture period. Then, we compared OK-432-stimulated LAK (OK-LAK) cells with standard LAK (sLAK) cells in terms of their rate of proliferation and cytotoxicity. OK-LAK cells proliferated more rapidly than sLAK cells. The cytotoxicity of OK-LAK cells increased, whereas that of sLAK cells decreased. We also investigated the phenotypic differences between these two types of LAK cells and found that, on day 21, the OK-LAK cells consisted mostly of CD3-CD56+ NK cells, whereas the sLAK cells consisted mostly of CD3+CD56- T cells. The difference in their level of cytotoxic potential might be explained by the difference of predominant phenotype.

Antigens, CD↗