PubMed Health⌕ Search

Biomedical subjects

T Kitajima

Publications and source records attributed to T Kitajima.

At least 163 records · Page 9Linked to original sources
PubMed1993

Roles of CD4+ and CD8+ cells in UVB-induced suppression of splenic alloantigen-presenting function.

Whole body ultraviolet light (UV) radiation causes systemic immunosuppression. Splenic antigen-presenting cell (APC) activity is decreased by UV radiation. To determine whether splenic CD4+ or CD8+ cells are involved in the UV-induced depression of splenic alloantigen-presenting function, we investigated the effect of in vivo UV radiation on the splenic stimulatory function in allogeneic mixed lymphocyte reaction in mice after the elimination of CD4+ or CD8+ cells by administering anti-CD8 or anti-CD4 Ab. Ab-treated and non-treated mice were exposed to UVB radiation (2.5 kJ/m2) twice or eight times. Two exposures to UVB radiation significantly suppressed the splenic alloantigen-presenting function of mice previously treated with anti-CD4 Ab, but hardly affected that of anti-CD8 Ab-treated or non-treated mice 2 days after the last radiation. On the other hand, eight exposures to UVB radiation suppressed this function in all mice. FACS analysis revealed that the UV-induced suppression is not associated with a significant decrease in the number of IA+ cell, as stimulator cells. It is suggested that CD4+ cells are somewhat preventive of the UV-induced depression of splenic allo-antigen-presenting function.

Animals↗
PubMed1993

Role of endothelin and platelet-activating factor in indomethacin-induced gastric mucosal injury in rats.

The current study was designed to investigate the role of two potent vasoactive substances, endothelin (ET) and platelet-activating factor (PAF), in the pathogenesis of indomethacin-induced gastric lesions in rats. Treatment with anti-ET antibody before indomethacin administration resulted in a significant decline in the total length of the lesions as determined by gross evaluation. In contrast, CV-6209, a specific PAF antagonist, had no effect on the total length of the lesions. The results strongly suggest the incorporation of endogenous ET in the mechanism of gastric damage after indomethacin administration.

Animals↗
PubMed1993

Spindle cell carcinoma arising in a port-wine stain.

We report a 75-year-old man with a port-wine stain (PWS) in whom spindle cell carcinoma (SCC) arose within a hemangiomatous area. Although reports on basal call carcinoma in association with a PWS exist, no literature is available about the development of an SCC within a PWS.

Aged↗
PubMed1993

Effect of a single exposure to in vivo UVB radiation on the allogeneic mixed lymphocyte reaction of spleen cells.

We investigated the effect of a single exposure to in vivo UVB radiation on the splenic T cell alloreactivity and antigen presenting cell (APC) function needed for alloantigen presentation. Splenic T cells from UVB-irradiated C57BL/6 mice were used as responders, and spleen cells from UVB-irradiated BALB/c mice were used as stimulators for a source of APCs in mixed lymphocyte culture. A single UVB radiation suppressed T cell alloreactivity, although the proliferative response to T cell mitogens was still normal. Moreover, UVB radiation impaired APC function. FACS analysis revealed a reduction not in the number of APCs but the intensity of class II alloantigen expression on APCs. Our findings suggest that, unlike repeated UVB exposure which impairs splenic APC function by the decrease in the number of APCs, a single UVB exposure impairs APC function by decreasing class II alloantigen expression.

Animals↗
PubMed1993

[Anesthetic management of a patient with Bernard-Soulier syndrome].

Bernard-Soulier syndrome (BSS) is a hereditary hemorrhagic disease characterized by prolonged bleeding time due to abnormal platelet aggregation and giant platelets. Transfusion of platelet-rich plasma is the only treatment available for the hemorrhagic episodes in patients with this disease. A 20-year-old female with BBS was scheduled for sagittal osteotomy of the mandibular rami under general anesthesia. Anesthesia was induced with fentanyl and diazepam, and was maintained with nitrous oxide, fentanyl, and 0.5% enflurane. No exacerbation of the bleeding tendency was observed during or after the surgery. We consider that the use of halothane should be avoided in patients with BBS because it may inhibit the aggregation of platelets and prolong the bleeding time.

Adult↗
PubMed1993

[Influence of bilateral stellate ganglion block on hemodynamics].

This study was designed to investigate the influence of bilateral stellate ganglion block (SGB) on hemodynamics in 15 mongrel dogs. Following general anesthesia, each dog received SGB with 1.5% mepivacaine. Cardiovascular effect of bilateral SGB was assessed by measuring mean artery pressure (MAP), heart rate (HR), cardiac output (CO), right atrial pressure (RAP), mean pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP) and common carotid arterial blood flow (CCAF). These were measured directly by a Swan-Ganz catheter and ultrasonic blood flow meter, during the first 15 minutes after SGB. A decrease of MAP and HR was observed after bilateral SGB. CO decreased for 13% compared with the control value. However, this change was not statistically significant. There was a significant increase in the bilateral CCAF, but the degree of the increase of CCAF was greater after unilateral SGB than after the bilateral SGB.

Animals↗
PubMed1993

[Analysis of water content in young rats brain edema by Raman spectroscopy].

Cerebral edema, classified into vasogenic edema and cytotoxic edema, has long been studied and recognized to be complicated. The authors studied the cerebral edema models of young rats suffered from cryo-injury and triethyl tin chloride (TET) injury by Raman spectroscopy which can physiologically evaluate the cerebral water content (%) of very restricted area. The cryo-injury model was conducted in the following manner. A cryo-probe (-196 degrees C) was contacted to the exposed cranium for 20 seconds in an anesthetized 4-5-week-old Sprague-Dawley young rat. A coronal section of the injured brain covered with a slide glass and wrapped by Parafilm was obtained 2, 4, 6, 8, 12, 24, 48, 72 hours after the cryo-injury in order to measure the water content by Raman spectroscopy employed by Tashibu and Huizinga. TET injury model was obtained by intraperitoneal administration of TET (4.5 mg/Kg). The water content was observed by the same manner as for the cryo-injury model. Subsequent to the cryo-injury, the water content of the white matter which seemed to be higher than in adult rats increased rapidly and persisted in the same condition within 72 hours. Subsequent to TET injury, the water content of the white matter increased more rapidly than that of the gray matter, however, in adult rats the water content of the gray matter showed more rapid increase than that of the white matter. Increased water content followed by TET injury was higher in adult rats than in young rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1992

Synthesis of an octasaccharide fragment of high-mannose-type glycans of glycoproteins.

O-(alpha-D-Mannopyranosyl)-(1----2)-O-(alpha-D-mannopyranosyl)-(1----3)- O- [(alpha-D-mannopyranosyl)-(1----2)-O-(alpha-D-mannopyranosyl)-(1----6)]- O- (alpha-D-mannopyranosyl)-(1----6)-O-(beta-D-mannopyranosyl)-(1----4)-O-( 2- acetamido-2-deoxy-beta-D-glucopyranosyl)-(1----4)-2-acetamido-2-deoxy- glucopyranose, an octasaccharide fragment of high-mannose type glycan of glycoproteins, was synthesized. Crucial glycosylation of trisaccharide intermediate, benzyl O-(2,4-di-O-benzyl-beta-D-mannopyranosyl)-(1----4)-O-(2-acetamido-3,6-di -O- benzyl-2-deoxy-beta-D-glucopyranosyl)-(1----4)-2-acetamido-3,6-di-O-benz yl-2- deoxy-beta-D-glucopyranoside, was successful only with a di-O-acetyltetradeca-O-benzyl-D-mannopentaosyl chloride. The use of the corresponding hexadeca-O-acetyl-D-mannopentaosyl bromide did not give the desired product.

Acetylglucosamine↗
PubMed1992

Histological detection of c-myb and c-myc proto-oncogene expression in infiltrating cells in cutaneous lupus erythematosus-like lesions of MRL/l mice by in situ hybridization.

A relationship between lymphocytic activation and the overexpression of proto-oncogenes such as c-myb or c-myc has been demonstrated in human autoimmune disease. In autoimmune-prone MRL/l mice, which spontaneously develop lupus erythematosus (LE)-like lesions on the back, increased expression of myb RNA has been found in the lymphoid organs. We detected the overexpression of c-myb and c-myc proto-oncogenes in infiltrating cells in the cutaneous lesions of MRL/l mice by using in situ hybridization. No specific hybridization signals of either of the probes used were seen in the nonlesional skin of MRL/l mice or in the apparently normal skin of aged MRL/n and young MRL/l mice. These results suggest that the increased expression of myb and myc proto-oncogenes in the cutaneous LE-like lesions of MRL/l mice is related to a state of activation in the infiltrating cells and is involved in the development of these lesions.

Animals↗
PubMed1992

An ESR-CT imaging of the head of a living rat receiving an administration of a nitroxide radical.

Three-dimensional ESR imaging of a living rat has been performed by an L-band ESR system, which is composed of an L-band ESR spectrometer, a field gradient coil, and a data processor. The imaging was carried out by Lauterbur's method. A nitroxide, 3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (Carbamoyl-PROXYL), was used as an imaging agent in saline solution at a concentration of 0.2 M and administered intraperitoneally to obtain a constant concentration in the head for about an hour. It took about 40 min to obtain one set of ESR-CT images. The cross-sectional images were made, both as coronal and horizontal images. In the images of the rat head the nitroxide-rich region was clearly distinguished from the deficient region. The nitroxide-deficient areas corresponded well to the brain of the rat.

Animals↗
PubMed1992

[Differences of regional blood flow after stellate ganglion block with local anesthetic and that after stellate ganglion resection using ultrasonic Doppler flowmeter].

Ten mongrel dogs were divided into two groups; stellate ganglion block (SGB, n = 5) group and stellate ganglion resection (SGR, n = 5) group. Anesthesia was induced with pentobarbital 25 mg.kg-1. The animals were mechanically ventilated to maintain a constant PaCO2 (35-40 mmHg). Left common carotid arterial flow (CCAF), left external carotid arterial flow (ECAF), left vertebral arterial flow (VAF) and left brachial arterial flow (BAF) were measured using an ultrasonic transit time flowmeter. Internal carotid arterial flow (ICAF) was calculated by subtracting ECAF from CCAF. After thoracotomy, the first SGB with 0.5% mepivacaine 1.5 ml or SGR was performed. Ninety minutes after the first SGB, the second SGB was performed. The data were taken for 180 minutes after the first SGB or SGR. In SGB, CCAF and BAF increased significantly for the duration of action of local anesthetic. But VAF and ICAF increased significantly for a short time after the block. In SGR, CCAF, BAF and ICAF increased significantly during the experiment. But VAF showed a transitory increase immediately after the resection. The authors conclude that sympathetic ganglion block with local anesthetic should be performed repeatedly when increase of blood flow in blood vessels with strong autoregulation from the brain is anticipated.

Animals↗
PubMed1991

Chemical synthesis and biological activities of 6,6'-di-O-mycoloyl-beta,beta- and -alpha,beta-trehalose.

6,6'Di-O-mycoloyl-beta,beta-trehalose (beta,beta-TDM) and 6,6'-di-O-mycoloyl-alpha,beta-trehalose (alpha,beta-TDM) were synthesized and their toxicity and ability to activate peritoneal macrophages in situ were examined in mice, in comparison with 6,6'-di-O-mycoloyl-alpha,alpha-trehalose (TDM). Both beta,beta-TDM and alpha,beta-TDM caused a decrease in body weight two days after injection, however the weights reverted to a normal level. No deaths were caused by either analog. On the other hand, TDM showed potent toxicity, causing decrease in body weight and death of all animals injected. Beta,beta-TDM and alpha,beta-TDM were effective in the in situ activation of mouse peritoneal macrophages.

Animals↗
PubMed1991

A model of the mechanism of cooperativity and associativity of long-term potentiation in the hippocampus: a fundamental mechanism of associative memory and learning.

Long-Term Potentiation (LTP) has three properties: (1) input specificity, (2) cooperativity and (3) associativity. In a previous paper, we proposed an integrated model of the mechanisms of the induction and maintenance of LTP with input specificity. In this paper, a model of the mechanism of cooperative and associative LTP is described. According to computer simulations of the model, its mechanism is based on the spread of synaptic potentials.

Animals↗