Biomedical subjects

T Kosaka

Publications and source records attributed to T Kosaka.

At least 127 records · Page 7Linked to original sources

PubMed1996

Dense GABAergic input on somata of parvalbumin-immunoreactive GABAergic neurons in the hippocampus of the mouse.

GABAergic neurons in the hippocampus proper are greatly diverse in their morphological and physiological features. In the present study we examined whether or not they are also diverse regarding the density of GABAergic input on their somata. GABAergic neurons were immunocytochemically identified with antibodies against glutamic acid decarboxylase (GAD), and the densities of GAD-immunoreactive (GAD-IR) boutons that abutted on GAD-IR somata were estimated by conventional light microscopic, combined light and electron microscopic, and confocal laser scanning microscopic analyses. GAD-IR somata were apparently diverse regarding the density of GABAergic input on them, and those surrounded by higher densities of GAD-IR boutons were distributed mainly in the strata pyramidale and oriens of the CA3 and CA1 regions and could be correlated to a parvalbumin (PV)-IR subpopulation of GABAergic neurons. Quantitative analysis clearly revealed the statistically significant difference between PV-positive and PV-negative GAD-IR neurons in the densities of their somatic GAD-IR boutons. Particularly, most of PV-IR neurons in the CA3 stratum pyramidale as well as some in other layers are characterized by an exceedingly high density of perisomatic GAD-IR boutons. Furthermore, the majority of GAD-IR boutons on PV-IR somata in the stratum pyramidale were also PV-IR. Bilateral transection of the fimbria-fornix, which was supposed to remove GABAergic afferents from the septum, had only partial effects on the densities of PV-IR boutons on PV-IR somata, indicating these PV-IR boutons mainly originated from intrinsic PV-IR neurons. These observations indicate the dense mutual connection between PV-IR GABAergic neurons through perisomatic synaptic contacts, particularly in the stratum pyramidale.

Animals↗

PubMed1996

Production, binding characteristics and protective immunity of monoclonal antibody to pneumococcal type-9V conjugate.

A monoclonal antibody (MAb) to pneumococcal type-9V polysaccharide (PS) was produced using PS conjugated to inactivated pneumolysin as the immunogen. The MAb to 9V PS was of the IgG1 subclass. The antigen-antibody reaction increased rapidly at low concentrations and reached a plateau at 10 micrograms PS/ml as measured by nephelometry of the group 9 PS against 9V MAb binding. In contrast, the binding of group 9 PS against rabbit 9V antiserum (AS) increased proportionally and continued to increase up to the highest concentration of PS tested (20 micrograms PS/ml). The 9V MAb reacted with all group 9 PSs (9A, 9L, 9N and 9V) by immunodiffusion. In the homologous 9V Ag-MAb reaction, there were marked differences in the inhibition of binding by the cross-reactive 9L PS (19.2% inhibition) and the 9N PS (0.2%). In contrast, inhibition of the homologous 9V Ag-rabbit AS binding by cross-reactive 9L and 9N PSs ranged from 57.8 to 62.7%. Removal of the O-acetyl group from 9V PS by alkali hydrolysis resulted in decreased binding with rabbit 9V AS. However, the binding reaction with 9V MAb was less affected by the loss of O-acetyl content. The 9V MAb was both opsonic and passively protected young mice against challenge with type-9V pneumococci.

Animals↗

PubMed1996

Case report: portal-systemic encephalopathy due to a congenital extrahepatic portosystemic shunt.

We present a case of portal-systemic encephalopathy due to a congenital splenorenal shunt. A 69 year old woman was admitted to hospital because of recurrent episodes of disturbed consciousness. The present episode had begun 3 months prior to admission. Although the patient demonstrated mildly slurred speech, the remainder of her neurological examination was unremarkable. She showed no clinical signs of portal hypertension and her liver function, except for a serum hepaplastin test of 58% and an ICG retention rate of 28% at 15 min, was normal. Her serum ammonium level was 210 micrograms/dL. The venous phase of a superior mesenteric arteriogram revealed a splenorenal shunt and narrowing of the portal vein, which was 4 mm in diameter. The histological findings, demonstrated by a needle liver biopsy specimen, were consistent with mild fibrosis and lymphocytic infiltration. Following the diagnosis of a splenorenal shunt in the absence of liver cirrhosis, ligature of the shunt was performed with a splenectomy. The portal vein pressure after ligature of the shunt rose from 12.5 to 18.8 mmHg. This shunt was thought to be of congenital origin. The high preoperative serum ammonia concentration decreased to the normal range postoperatively and the serum hepaplastin test and ICG retention rate similarly improved postoperatively. A follow-up superior mesenteric arteriogram was performed during the venous phase, demonstrating resolution of the shunt and decreased portal vein narrowing. The patient has suffered no further episodes of disturbed consciousness postoperatively.

Aged↗

PubMed1996

Diffusivity of oxygen in microvascular beds as determined from PO2 distribution maps.

Dynamic changes in the distribution of PO2 in the rat mesentery were measured to determine the O2 diffusion coefficient (DO2) and consumption rate (VO2). The distribution of PO2 was obtained in two-dimensional maps by microscopic fluorometry on the basis of oxygen quenching. The corresponding vasculature was also recorded on a video recorder to analyze the PO2 distribution consistent with the arrangement of the microvessels. Anesthetized rats breathing room air were subjected to 100% O2 ventilation to induce dynamic changes in PO2 distribution. We assumed a homogenous and constant VO2 in the tissue, and a one-dimensional diffusion equation was applied to simulate oxygen transport. The PO2 data corresponded very well to the theoretical curves, and calculated DO2 was 1.04 +/- 0.78 X 10(-5) cm2/s (mean +/- SD, n = 38) and VO2 was 8.2 +/- 3.9 x 10(-6) cm3 O2.cm-3 tissue.s-1 (n = 27) at 37 degrees C. However, PO2 values at points remote from the arterioles remained higher than the theoretical prediction.

Animals↗

PubMed1996

Effect of chitosan implantation on activation of canine macrophages and polymorphonuclear cells after surgical stress.

The effect of cotton type chitosan implantation under the skin on the immunological response mediated by macrophages and whole blood was evaluated by chemiluminescence (CL) in dogs. The number of white blood cells was significantly decreased until 120 hr after operation in the control group (p < 0.05), while chitosan implantation increased the number of white blood cells, particularly neutrophils, from 24 to 96 hr after implantation (p < 0.05). The CL response of whole blood in the control group seemed to be reduced at 48 and 96 hr after operation (p < 0.05), but in the chitosan groups it maintained higher activity until 120 hr after implantation (p < 0.05). The macrophage activity measured by CL assay in the control group was markedly decreased from 24 to 120 hr after operation, and that for the 5 mg/kg chitosan group was also decreased at 24 and 48 hr after implantation (p < 0.05), although high activity was observed from 72 to 120 hr after implantation (p < 0.05). Neither 5 mg/kg nor 10 mg/kg chitosan groups showed any reduction in CL response of macrophages after operation, and the 20 mg/kg chitosan group retained high CL response of macrophages until 120 hr after operation (p < 0.05). These findings suggest that chitosan may be an efficacious and useful immunopotentiator for preventation of immunosuppression after surgery.

Adjuvants, Immunologic↗

PubMed1996

Activation of canine monocytes and polymorphonuclear cells by serum thymic factor (FTS) in vivo.

The effect of serum thymic factor (FTS) was evaluated from the immunoresponse augmented in canine monocytes and polymorphonuclear cells (PMN) using the chemiluminescence technique. FTS did not affect the number of leukocytes and differential count of leukocytes. CL activity of the whole blood was significantly elevated by FTS from 72 hr to 120 hr after administration (p < 0.05), and that at 96 hr after administration was about 3-fold higher than that before the administration. The CL response of PMN was significantly elevated by FTS administration from 24 hr to 96 hr after administration (p < 0.05), and that at 48 hr after administration was about 7-fold higher than prior treatment. FTS also significantly elevated the CL response of monocyte from 24 hr to 96 hr after administration (p < 0.01), and the CL count of monocyte in 24 hr and 48 hr was about 100-fold higher than that before FTS administration. These findings suggested that FTS may be efficacious and useful immuno-potentiator for canine monocytes and PMN.

Animals↗

PubMed1996

Spheroid cultures of human hepatoblastoma cells (HuH-6 line) and their application for cytotoxicity assay of alcohols.

Spheroid cultures of human hepatoblastoma cells (HuH-6 line) were established by rotating 3 x 10(6) cells/3 ml culture medium in 25-ml Erlenmeyer flasks on a gyratory shaker. The size of the spheroids rapidly increased until 4 days of culture, and thereafter their size gradually increased until 8 days of culture. A considerable amount of lactate dehydrogenase (LDH) was detected in the culture medium at 24h after seeding because of cell damage by subculturing, but thereafter the amount released was small, indicating that the spheroids were in healthy condition. Albumin production, one of the differentiated functions of hepatocytes, was higher in spheroid cultures than in monolayer cultures. Using this spheroid culture model, the cytotoxic effects of alcohols on HuH-6 cells were studied by measuring the activity of LDH released in the medium from damaged cells. The results indicate that the increasing order of toxicity of the alcohols was as follows: methanol < ethanol < propanol.

Albumins↗

PubMed1996

Comparison of various methods of assaying the cytotoxic effects of ethanol on human hepatoblastoma cells (HUH-6 line).

The sensitivity of five kinds of cytotoxicity assays using ethanol on human hepatoblastoma cells (HUH-6 line), which were cultured as monolayers or spheroids, was compared. Ethanol was chosen as a test because it acts on cell membranes directly without being metabolized and exerts its cytotoxicity. The assay methods used were as follows: 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), colony formation, cell growth and DNA assays. The sensitivity of the assays was: LDH < DNA < cell growth < MTT < colony formation. LDH assay had the advantage that the same culture could be used for multiple assays, but when a small number of cells were assayed, no significant increase in the release of LDH was detected in the assay cultures compared with the control cultures. Although the DNA and cell growth assays were more sensitive than the LDH assay, the extent of cell damage may be underestimated because the damaged cells and DNA present in the cultures are included in the assay samples. On the other hand, both MTT and colony formation assays showed a high sensitivity. The MTT assay was done within 24 h after ethanol was added to the cultures and was applicable to both monolayer and spheroid cultures, while the colony formation assay required 1-2 weeks and it was applicable only to monolayer cultures. Taken together, the MTT assay was the most suitable method to evaluate the cytotoxic effects of ethanol on HUH-6 cells cultured as either monolayers or spheroids.

Cell Survival↗

PubMed1996

[A study of arterial infusion chemotherapy for gastric cancer patients with peritoneal metastasis].

We analyzed the clinical response, toxicities, out-patient and overall survival time among 41 gastric cancer patients with peritoneal metastasis to evaluate chemotherapies and drug delivery routes. Sixteen patients were treated by arterial infusion (AI) and 25 by systemic therapy (ST), with either 5-FU/MTX (FMTX) therapy or 5-FU/CDDP (FP) therapy. Partial response was observed in 8 patients (50%) among 16 with AI and in 6 (24%) among 25 with ST (p = 0.09). There were no differences in the incidence of side effects (> or = grade 2 according to WHO criteria) between AI and ST group, at 25% and 36%, respectively. No significant differences were observed in either survival time or home care duration among patients with AI chemotherapy and those with ST procedure.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1995

Flow cytometer and imaging device used in combination.

This report presents a flow cytometer devised by the authors and equipped with a CCD camera to obtain images of selected particles. Each image is linked to a point in the scattergram from which it can be retrieved from memory. The system uses an argon ion laser for flow-cytometric analysis and a diode-pumped pulse laser (532nm) to generate CCD images. Aggregated platelets in a blood sample and casts in a urine sample can be detected by this system. A fast flow rate is suitable for efficient flow-cytometric detection, and image resolution is sufficiently adequate for recognizing aggregated platelets and casts. Flow-cytometric and morphological data are used together to distinguish different types of cells in the same region on the scattergram and identify cells present in extremely small numbers among the majority.

Blood Platelets↗

PubMed1995

Collisionally-activated dissociation spectra of linear peptides in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Collisionally-activated dissociation (CAD) studies of linear peptides were performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Four different gases, viz. helium, nitrogen, argon and xenon, were introduced into a gas cell, installed close to the ion source of TOF mass spectrometer, to obtain high-energy CAD information. The CAD spectral patterns for the linear peptides obtained using the four gases were almost the same as each other. The fragments characteristically obtained in conventional high-energy CAD using tandem mass spectrometry were observed also in these spectra. A difference between CAD spectra and post-source decay product-ion spectra has been demonstrated.

Amino Acid Sequence↗

PubMed1995

A case of gallbladder cancer associated with a common bile duct neuroma, and a cystic lesion of the liver with histologic findings similar to those of an inflammatory pseudotumor.

We report a rare case of gallbladder cancer associated with a common bile duct neuroma, and a cystic liver lesion with histologic findings similar to an inflammatory pseudotumor, in a patient who had had no previous abdominal surgery. The patient was a 62-year-old man whose major complaint was fever. Ultrasonography and a computed tomography scan revealed gallstones, an elevated lesion in the gallbladder, and a cystic liver lesion. Endoscopic retrograde cholangiopancreatography demonstrated stenosis of the common bile duct. Cultures of the cystic fluid and gallbladder bile were positive for Staphylococcus aureus. The patient underwent hepatectomy (inferior S4, S5, and S6), cholecystectomy, resection of the common bile duct, and right hemicolectomy. The resected specimens revealed gallbladder cancer with the microscopic appearance of a papillary adenocarcinoma, and a 12 x 4.5 x 3.5 cm cystic liver lesion with a wall 7 mm thick. Histologic studies of the wall of the cystic liver lesion revealed infiltration by histiocytes and plasma cells, and the presence of fibrous connective tissue, which findings are characteristic of inflammatory pseudotumors. A 9 x 6 mm elevated lesion, with the microscopic appearance of a neuroma, was resected from the common bile duct.

Adenocarcinoma, Papillary↗

PubMed1995

Correlation between canine NK cell mediated cytotoxicity and radical production.

We investigated the relationship between natural killer (NK) mediated cytotoxicity and radical production in canine peripheral blood lymphocytes (PBLs). Canine NK cell mediated cytotoxicity, measured by 51Cr release assay, was found to be the highest in the T-cell (Thymus cell) subpopulation which partitioned into the 35-40% percoll fraction by centrifugation through a discontinuous gradient. Radical production showed a similar tendency in luminol-dependent chemiluminescence (CL) assay. Furthermore, enrichment of large granular lymphocytes (LGL) was observed in the cell fraction from the same percoll density. These results suggest that NK cell mediated cytotoxicity is related to radical production in canines.

Animals↗

PubMed1995

Distribution of the calcium binding proteins, calbindin D-28K and parvalbumin, in the subicular complex of the adult mouse.

The immunohistochemical localizations of two specific calcium binding proteins, calbindin D-28K (calbindin) and parvalbumin (PV) were examined in the subicular complex, that is, the subiculum, presubiculum, and parasubiculum, of the adult mouse and were compared in detail with staining pattern of the acetylcholinesterase (AChE) histochemistry. The calbindin immunoreactivity exhibited a conspicuous regional and laminar pattern of distribution, which somewhat resembled the AChE staining pattern but was apparently different from the latter in various points. The PV immunoreactivity also exhibited a characteristic regional difference, although less prominent. The subiculum could be divided into two subregions, intensely calbindin-immunoreactive (calbindin-IR) and AChE stained proximal subiculum and only faintly calbindin-IR and AChE stained distal subiculum. In the subiculum most of calbindin-IR neurons were pyramidal cells which were clustered in the superficial half of the cell layer in the proximal subiculum and appeared to be segregated from calbindin negative pyramidal cells located in the distal subiculum and in the basal part of the proximal subiculum. In the presubiculum calbindin-IR neurons were clustered in layer 2, most of which were supposed to be presubicular pyramidal cells. In the parasubiculum, the overall immunostaining pattern of PV and calbindin were somewhat complementary. In the transition area calbindin-IR neurons were clustered but few PV-IR neurons were located, and thus the distribution of immunoreactive neuronal somata was apparently different from the adjacent parts of the parasubiculum, indicating that the transition area might be a separate entity. In addition to calbindin-IR presumable principal neurons, calbindin-IR and PV-IR nonpyramidal cells were scattered throughout the subicular complex. Furthermore, these two calcium binding proteins were colocalized in some nonpyramidal cells in the subicular complex. The present study revealed some new aspects of the areal and laminar organization of the subicular complex, which had not been shown by previous classical purely morphological approaches.

Acetylcholinesterase↗

PubMed1995

Alteration of gamma-ray-induced chromosome aberration by 0.5 M NaCl in Chinese hamster cells.

Hypertonic treatment (0.5 M NaCl in phosphate-buffered saline, pH 7.2) at 37 degrees C for 20 min slightly delayed the mitotic frequency for non-irradiated cells in G1 and G2 phases. The mitotic frequency for irradiated cells in G2 was delayed by hypertonic treatment, and that in G1 was slightly delayed by hypertonic treatment. Hypertonic treatment in non-irradiated cells did not induce any chromosomal or chromatid aberrations in either G1 or G2. Chromosomal aberrations caused by gamma-irradiation were slightly enhanced by hypertonic treatment, and chromatid aberrations were markedly enhanced by hypertonic treatment. The enhancement ratio of gamma-irradiation-induced chromatid breaks and exchanges was 1.4 and 3.0, respectively. This cell cycle dependency of chromosome aberrations induced by postirradiation hypertonic treatment was the same as that of cell survival. These findings suggested that hypertonic treatment modifies the rejoining of DNA strand breaks in G2, but slightly modifies that in G1.

Animals↗

PubMed1995

Release of natural killer cytotoxic factor (NKCF) from canine natural killer (NK) cells stimulated with cytoplasmic membrane of target cells.

The presence of canine natural killer cytotoxic factor (NKCF) and the mechanism of the release of the NKCF by canine natural killer (NK) cells were studied. The cytotoxicity in the culture supernatant of effector cells cultured with target cells was dependent on the count of NK cells. Therefore, this suggests that the cytotoxic factor in this culture supernatant is NKCF. The NK-sensitive live target cells stimulated the release of NKCF from NK cells, but the NK-insensitive target cells did not. Moreover, NKCF was also released from NK cells stimulated with either killed target cells or their cytoplasmic membrane as well as live target cells. These findings suggest that the structure of the cytoplasmic membrane of target cells is involved in the recognition, binding and the release of NKCF by NK cells.

Animals↗

PubMed1995

A simple construction of dual-slit red cell velocimeter.

A simple method of building a dual-slit red cell velocimeter is introduced. The basis of this technique is to utilize the body of a 35-mm photomicrography camera as the photometric device, exactly centering a pair of highly sensitive photodiodes on the film plane of the camera. By this arrangement, the microvascular image can be accurately focused on the sensing windows of the photodiodes. Because this velocimeter is not based on videophotometry, it was possible to measure red cell velocity up to 30 mm/s in the benchmark test. The maximum red cell velocity actually measured in the rat mesenteric microvessels (6.0 to 48 microns in diam) was 9 mm/s.

Blood Flow Velocity↗

PubMed1995

Chemically defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb.

Chemically-defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb were revealed immunocytochemically using antibodies against gamma-amino butyric acid (GABA), tyrosine hydroxylase (TH), methionin-enkephalin-Arg6-Gly7-Leu8 (ENK), calretinin (CR), calbindin-D28K (calbindin) and thyrotropin-releasing hormone (TRH). GABA-like immunoreactive (GABA-LIR) neurons and CR immunoreactive (CR-IR) neurons were most numerous; they were about 1.5-3 times more numerous than calbindin immunoreactive (calbindin-IR), TH immunoreactive (TH-IR), ENK-like immunoreactive (ENK-LIR) and THR-like immunoreactive (TRH-LIR) neurons. We identified at least three distinct chemically-defined neuron groups, GABA-LIR neurons, CR containing neurons and calbindin containing neurons, since these three neuron groups were almost separate from one another. On the other hand, TH-IR and ENK-LIR neurons were nearly included in and thus considered to be subpopulations of GABA-LIR and CR-IR neurons, respectively, for about 80% of these two neuron groups contained GABA-L and CR immunoreactivities, respectively. TRH-LIR neurons appeared to be divided into two subpopulations, one containing the GABA-L immunoreactivity and the other containing the CR immunoreactivity. Thus in the glomerular layer of the rat olfactory bulb, GABA-LIR, CR-IR and calbindin-IR cells could be considered to be three distinct chemically-defined neuron groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons groups, whereas TH-IR, TRH-LIR and ENK-LIR neurons were regarded as their subpopulations. Furthermore, some neurons are supposed to contain three substances (e.g. GABA + TH + TRH, GABA + TRH + EnK, CR + TRH + ENK, GABA + TRH + CR) or a few might even contain four substances (e.g. GABA + TRH + CR + ENK). Preliminary quantitative analysis using the optical disector method showed percentages of these three main neuron groups to total cells in the glomerular layer; that is, neuron groups containing GABA, CR and calbindin were about 20%, 20% and 10%, respectively.

Animals↗