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Biomedical subjects

T Yamane

Publications and source records attributed to T Yamane.

At least 307 records · Page 17Linked to original sources
PubMed1994

Immunohistochemical study on blood-brain barrier in congenitally hydrocephalic HTX rat brain.

The purpose of the present study is to examine the blood-brain barrier in brain of congenital hydrocephalus HTX rats. We investigated the rat brain from postnatal day 1 to 44 using light and electron microscopy and immunohistochemical methods with monoclonal anti-blood-brain barrier (BBB) antibody. HTX rats developed hydrocephalus at 1-2 days after birth. Most rats succumbed to brain changes within 4-5 weeks. Among 136 HTX rats examined, 45 rats succumbed within 1 week after birth, 29 rats between 1-2 weeks, and 4 rats 27-44 days after birth. Out of 88 hydrocephalic rats 54 showed a marked ventricular dilatation, and 34 showed a mild dilatation. Dilatation of lateral ventricles was mild in the rats at 1-2 days after birth, but 3-14-day-old rats showed moderate or marked dilatation. 15-30 days after birth the rats developed mostly marked dilatation of lateral ventricles and third ventricle. Lateral ventricles and third ventricle showed a symmetric dilatation, but ependymal cell layers were well preserved. Aqueduct exhibited no dilatation in any rat. There were spongy appearances and cystic cavities in the white matter around the lateral ventricles. There were glial fibers and capillaries across the cystic cavities. Cystic lesions were also found in the deep subcortical white matter, consisting of spongy changes with extended extracellular spaces and microcysts in the white matter. Immunohistochemically, the anti-BBB reactivity in the normal control rats was at first weak at 2 weeks after birth and increased with the course of development, prominently 4 weeks after birth. Three- and four-week-old HTX rats with hydrocephalus showed moderate positive anti-BBB reaction in the cerebral cortex, the basal ganglia, and around the aqueduct but only a very weak reaction in the deep subcortical white matter and in the subependymal area of lateral ventricles. Laminin immunoreactivity was not different in the capillaries of hydrocephalic brain as compared with normal brain. Electron microscopically, tight junctions were well formed between endothelial cells of capillaries in the subcortical white matter. Occasionally capillaries with partial defect of basal membrane could be found, where the cytoplasm of endothelial cell was protruding between pericytic cytoplasm. Swelling of astrocytic end-feet were found around the microvessels. The results suggest that at the site of the lesion there is underdevelopment or immaturity of the blood-brain barrier.

Aging↗
PubMed1994

[A case of brain abscess of the basal ganglia which resulted in disastrous outcome due to ventricular ruptures].

A case of deep-seated brain abscess that ruptured twice into the ventricle and resulted in death is presented. A 45-year-old man had experienced pyrexia and headache for 3 days before admission. On admission he was somnolent (GCS: 13) but there were no abnormal neurological findings except nuchal rigidity and Kernig's sign. Computed tomography (CT) scan showed a ring enhanced mass near the left caudate head and dilated ventricles. In comparison with CT performed at the former hospital it was diagnosed that a rupture into the ventricle of the brain abscess had occurred. Ventricular drainage was performed at once and white purulent cerebrospinal fluid was obtained. Thereafter, he was treated with some antibiotics and his conditions seemed to stabilize for a while. Serial CT images demonstrated that the size of the abscess seemed to be enlarging. Just when we planned to undertake stereotactic aspiration, the second ventricular rupture occurred and he died. According to this case, it is suggested that once a deep-seated brain abscess near the ventricular system is suspected, it should be aspirated by means of CT-guided stereotactic surgery immediately.

Basal Ganglia Diseases↗
PubMed1994

Three-dimensional black blood MR angiography of the liver during breath holding. A comparison with two-dimensional time-of-flight MR angiography.

In 2-D time-of-flight MR angiography (2-D TOF MRA) of the liver, artifacts caused by respiratory motion are unavoidable. Therefore, a 3-D black blood MRA of the liver was attempted in 7 healthy volunteers, using a 3-D gradient echo sequence which allows imaging during breath holding. 2-D TOF MRA was performed as well. In all subjects, 3-D MRA allowed visualization of the trunk, 1st-, and 2nd-order branches of the portal vein without interruption. Right 3rd-order branches were visualized without interruption in 6 of 7 subjects (85%). However, with 2-D MRA, the transverse portion of the left main portal vein could not be visualized in any subject, and the periphery of the portal vein was less clear than with 3-D MRA.

Adult↗
PubMed1993

Crystallographic refinement of Bowman-Birk type protease inhibitor A-II from peanut (Arachis hypogaea) at 2.3 A resolution.

The crystal structure of Bowman-Birk type protease inhibitor A-II from peanut was refined at 2.3 A resolution using a restrained least-squares method. The crystallographic R-factor is 0.196 for 7697 reflections with F > 3 sigma (F) in the range from 6.0 to 2.3 A resolution. Two molecules in an asymmetric unit are independently refined and, their structures are compared with each other. The inhibitor molecule has an elongated shape with two reactive sites, one at both ends of the longest dimension. As a secondary structure, a 4-stranded beta-sheet-like structure is found, in which two water molecules bind two 2-stranded beta-sheets together with six hydrogen bonds. The molecule is constructed by two homologous domains which are related by an intramolecular pseudo 2-fold axis. The structure and atomic B-factors of peptide loops containing a reactive site were compared with that of adzuki bean Bowman-Birk type inhibitor in the complex with bovine beta-trypsin. This comparison shows that no significant structural change occurs in the reactive site of inhibitor at the formation of the inhibitor-protease complex, but structural rigidity around the reactive site seems to increase.

Amino Acid Sequence↗
PubMed1993

Crystallization and preliminary X-ray studies on the trypsin inhibitor I-2 from wheat germ and its complex with trypsin.

A Bowman-Birk type trypsin inhibitor I-2, M(r) = 14 000, 123 amino-acid residues, isolated from wheat germ, and its complex with trypsin have been crystallized. For I-2 two morphologically different crystal forms were obtained. Crystal form 1 is tetragonal, P4(1)22 or P4(3)22, with a = 55.45 (2), c = 129.1 (2) A and V = 3.97 (2) x 10(5) A(3). The crystals diffract X-rays very anisotropically, to less than 6 A resolution normal to the c* direction, but up to 3 A resolution in the other directions. Crystal form 2 is monoclinic, space group C2. The cell parameters show significant variation even for crystals in the same batch. The median parameters are: a = 83.9, b = 41.5, c = 45.7 A, beta = 95.9 degrees and V = 1.58 x 10(5) A(3). The diffraction pattern is isotropic and reflections up to 2.2 A resolution were observed. The crystals of the complex between bovine trypsin and I-2 (2:1) belong to the orthorhombic space group P2(1)2(1)2(1) with a = 73.49 (2), b = 120.56 (3), c = 70.04 (2) A and V = 6.206 (5) x 10(5) A(3). The crystals diffract up to 2.3 A resolution, and contain one complex of 60 100 Da in an asymmetric unit.

Journal Article↗
PubMed1993

External pH regulates the slowly activating potassium current IsK expressed in Xenopus oocytes.

A slowly activating, delayed rectifier potassium current, IsK, was expressed in Xenopus laevis oocytes by injection of cRNA transcribed from a rat kidney cDNA clone. External acidification reversibly decreased the current amplitude. The effects were concentration dependent on protons with Kd at pH approximately 5.5 and a Hill coefficient of 1.0. External acidification reduced the maximal conductance (Gmax) without affecting the activation kinetics; this effect was not dependent on membrane voltages. These data suggest that H+ ions bind to the channel with a one-to-one stoichiometry, and this binding site may be located outside of the membrane electric field.

Animals↗
PubMed1993

Flow cytometric detection of recombinant human granulocyte-colony stimulating factor binding to leukemic cells.

To examine binding of recombinant human granulocyte-colony stimulating factor to myeloid cells, the factor was labeled with fluorescein isothiocyanate, and incubated with blood specimens, which were then analyzed by flow cytometry. Neutrophils demonstrated an increased fluorescence, while lymphocytes were negative. These cell fractions were used as controls for cytometric binding assays of leukemic cells. Six patients with lymphocytic leukemia were negative in this assay. Ten of 15 patients with myelocytic leukemia were positive. All patients (n = 5) in myeloblastic crisis of chronic myelogenous leukemia were also positive. The flow cytometry results correlated well with the results of colony formation in response to granulocyte-colony stimulating factor. The results indicate that our method is useful in predicting the susceptibility of leukemic cells to recombinant growth factors.

Flow Cytometry↗
PubMed1993

Enhancement of various non-specific immune effector functions in mice by local injection of aclacinomycin A adsorbed onto activated carbon particles (ACR-CH).

Local injections of aclacinomycin A adsorbed onto activated carbon particles (ACR-CH) augmented the cytotoxic activities of regional lymph node cells for 7 days. In contrast NK-activity was only slightly augmented by injections of aclacinomycin A (ACR) solution or activated carbon suspension. The effects were found in lymphocytes from all regions tested. NK-activity could only be detected when both adherent and non-adherent cells were present. The cell number of L3T4+ cells in each type of lymph node tested increased, and subset analysis of the lymphocyte subpopulations revealed an increase in the ratio of L3T4+/Lyt2+ cells, suggesting that the ACR-CH selectively increased and stimulated L3T4+ cells. Enhanced capacity of lymph node cells to produce cytokines, tumor necrosis factor (TNF) and interleukin-1 (IL-1) upon restimulation (with LPS) in vitro in the ACR-CH treated group was found. From these results, it appears that the new dosage form of aclacinomycin A, ACR-CH, with superior therapeutic efficacy against lymph node metastases, can also enhance the immune response of regional lymph node cells. The findings reported here will be valuable in the establishment of novel chemoimmunotherapeutic protocols using ACR-CH.

Aclarubicin↗
PubMed1993

Inhibitory effects of fucoxanthin, a natural carotenoid, on N-ethyl-N'-nitro-N-nitrosoguanidine-induced mouse duodenal carcinogenesis.

Fucoxanthin was shown to inhibit chemical carcinogenesis. Fucoxanthin is a natural carotenoid prepared from brown algae which is an ingredient used daily in Japanese food. In this study, all mice were given 0.01% N-ethyl-N'-nitro-N-nitrosoguanidine in their drinking water for 4 weeks. This was followed by 0.005% fucoxanthin in dimethylsulfoxide or the vehicle alone in the drinking water. In the 16-week fucoxanthin-treated group both the percentage of tumor-bearing mice and the average number of tumors per mouse were significantly lower than those of the control group. The results indicate that fucoxanthin inhibited duodenal carcinogenesis induced by N-ethyl-N'-nitro-N-nitrosoguanidine in mice.

Animals↗
PubMed1993

Abnormal systolic blood pressure response during exercise recovery in patients with angina pectoris.

OBJECTIVES: This study was conducted to clarify the mechanisms of the abnormal systolic blood pressure response after exercise in patients with angina pectoris. BACKGROUND: An abnormal systolic blood pressure response in patients with angina pectoris has been observed not only during exercise but also during the recovery period after exercise. However, the mechanisms of this abnormal response during recovery have not been elucidated. METHODS: Thirty-five patients with angina pectoris and 17 control subjects underwent bicycle ergometric studies after insertion of a Swan-Ganz catheter. RESULTS: In control subjects, all hemodynamic variables decreased rapidly after exercise. In 7 of the 35 patients, systolic blood pressure increased after exercise. The patients with angina were classified into two groups. In group I (17 patients), changes in systolic blood pressure during recovery were smaller than those in control subjects. In group II (18 patients) recovery of systolic blood pressure was normal. Changes in stroke index from rest to peak exercise were smaller in group I than in group II. Stroke index in both patient groups increased paradoxically during recovery. The increase in systemic vascular resistance index during recovery and the ratio of plasma norepinephrine concentration to cumulative work load were greater in group I than in group II. CONCLUSIONS: An abnormal systolic blood pressure response after physical exercise in patients with angina pectoris is indicative of severe myocardial ischemia during exercise and may be caused by an increase in stroke volume due to recovery from myocardial ischemia and increased systemic vascular resistance secondary to exaggerated sympathetic nervous activity.

Adult↗
PubMed1993

Enhancement of LAK-like activity and cytokine induction in regional lymph nodes and spleen cells of mice after intralymphnodal injection of OK-432, a killed streptococcal preparation.

A single dose of inactivated streptococci (OK-432) was injected into the popliteal lymph nodes of male CDF1 mice and its effects on popliteal, inguinal, and para-aortic lymph node cells and spleen cells were investigated and compared with the effects of subcutaneous injections of the same dosage of OK-432. Regional lymph node cells and spleen cells obtained from intralymphnodally injected mice lysed not only natural killer (NK)-sensitive YAC-1 cells, but also NK-resistant P-815 and meth-A cells. Lysis of target cells was inhibited when effector cells were treated with anti-Thy-1.2 or anti-Lyt-2.2 monoclonal antibody and complement, but no inhibition was apparent after treatment with anti-asialo-GM1 or anti-Lyt-1.2 antibody and complement. These results suggest that the effector cells are lymphocyte-activated killer (LAK) cells. An enhanced capacity of lymph node cells to produce cytokines, tumor necrosis factor and interleukin 1 upon restimulation with lipopolysaccharide was found only in intralymphnodally injected mice. Thus, the induction of LAK-like cells and cytokine production in regional lymph nodes and spleen cells by the intralymphnodal administration of OK-432 should be effective for the inhibition or treatment of lymph node metastases.

Animals↗
PubMed1993

Use-dependent block of Ca2+ current by moricizine in guinea-pig ventricular myocytes: a possible ionic mechanism of action potential shortening.

1. Whole cell patch clamp techniques were used to study the effects of moricizine on membrane currents in guinea-pig ventricular myocytes. 2. Application of moricizine caused reversible depression of the time-dependent outward K+ current. 3. The Na+/Ca2+ exchange current was not directly affected by moricizine. 4. Although moricizine hardly affected the L-type Ca2+ current when cells were stimulated at a frequency of 0.1 Hz, it suppressed the current at depolarized holding potentials in a use-dependent manner at 1 Hz. 5. Developments of use-dependent block of the Ca2+ current in the presence of moricizine were best expressed by two exponentials. Binding to both activated and inactivated states of the Ca2+ channel were supported from the binding kinetics study. 6. We concluded that moricizine suppressed the L-type Ca2+ current in a use-dependent manner and this might explain, at least in part, action potential shortening by the drug.

Action Potentials↗
PubMed1993

Synthesis and biological activity of 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives.

As a part of our studies on the syntheses of benzoxazinorifamycin derivatives, 3'-hydroxy-5'-aminobenzoxazinorifamycin derivatives were synthesized, and tested for their antimicrobial activities. The antimicrobial activities of these compounds against gram-positive and gram-negative bacteria were almost identical to those of rifampicin (RFP) and rifabutain (RFB), however, antimicrobial activities against Mycobacterium tuberculosis were superior to RFP, while being similar to RFB. 3'-Hydroxy-5'-(4-alkyl-1-piperazinyl)benzoxazinorifamycin derivatives also had in vitro potent activities against Mycobacterium avium complex (MAC). Their minimal inhibitory concentration values against MAC were 2-256 times greater than RFP and RFB. Their in vivo efficacies against M. tuberculosis and MAC, after oral administration to mice, were superior to RFP and RFB, except for RFB against M. tuberculosis activity in vivo. Although they were absorbed from the gastrointestinal tract, their plasma levels were lower than that of RFP. Among these 5'-(4-alkyl-1-piperazinyl) derivatives, 3'-hydroxy-5'-(4-isobutyl-1-piperazinyl)benzoxazinorifamycin, compound 19 (KRM-1648), was selected as the most promising and its preliminary pharmacokinetic characteristics in mice were investigated. Compound 19 was distributed much more in tissues, especially in spleen and lung, than in plasma and had a long elimination time from tissues.

Animals↗
PubMed1993

Early diagnosis of lumbar spondylolysis by MRI.

Radiography and CT and MRI scans of the lumbar spine were performed in young patients complaining of pain during extension of the lumbar spine but without neurological signs in the lower limbs. T1-weighted MR images in the coronal plane showed a hypo-intense area in the pars interarticularis before the detection of spondylolysis at that site by plain radiography or CT. We suggest that this may be useful in the early diagnosis of spondylolysis.

Adolescent↗
PubMed1993

[CSF in laboratory medicine].

The effect of granulocyte-colony stimulating factor (G-CSF) or macrophage-colony stimulating factor (M-CSF) on patients with malignant lymphoma was analyzed. G-CSF was administered for ten days after conventional chemotherapy causing an increase in the granulocyte and monocyte counts. The increase in these cells shortened the duration of a leukocyte count lower than 2000 or 3000/mm3. There were no detectable effects from G-CSF on other blood cells. M-CSF had no effect on any of these cells. Receptors of these cytokines on various types of leukemic cells were also analyzed by flow-cytometry using fluorescent isothianate-labelled G-CSF or M-CSF. With this simplified method, G-CSF receptors were detected on almost all of the myeloid acute leukemia cells, but not on the nonmyeloid leukemic cells. M-CSF receptors were also detected on all of the monocytic acute leukemic cells, but not on myelocytic or lymphocytic leukemic cells.

Acute Disease↗