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Biomedical subjects

K Fujimura

Publications and source records attributed to K Fujimura.

At least 19 recordsLinked to original sources
PubMed1992

Action of habenular efferents on ventral tegmental area neurons studied in vitro.

Action of habenular efferents on neurons of the ventral tegmental area (VTA) was studied with a slice preparation that preserved the habenula (Hb) and the VTA together with the interconnecting fiber bundle, the fasciculus retroflexus (FR). In the VTA, two types of neurons, presumably corresponding to the dopaminergic and nondopaminergic neurons, were discerned on the basis of the electrophysiological properties. Of 52 VTA neurons sampled, 42 [with the mean resting membrane potential of 56 +/- 7 mV (mean +/- SD)] responded with excitatory postsynaptic potentials (EPSPs) to FR stimulation. The EPSPs were monosynaptic in nature and rather weak in effect in the sense that they rarely triggered spikes. No significant differences in latency, duration, and time to peak were noted between the EPSPs generated in different types of neurons. FR stimulation evoked inhibitory postsynaptic potentials (IPSPs) in only six neurons, their resting membrane potential being 51 +/- 4 mV. The IPSPs frequently showed a fluctuation in latency. FR stimulation also produced antidromic responses in a few VTA neurons, but their long latencies precluded the possibility that the VTA-Hb projections contributed to the FR-evoked orthodromic responses in the VTA. EPSPs evoked by FR stimulation could be suppressed by kynurenic acid (1 mM). The findings indicate that the efferents of the Hb primarily have an excitatory effect on VTA neurons of any type and that the excitation may be mediated by amino acid receptors.

Animals↗
PubMed1992

Alexithymia and depression in families with alcoholics.

Alexithymia and depression in family members of alcoholics were examined among 48 families. Results were as follows: (1) The prevalence of alexithymia was 47.9% (23 cases), whereas that of depression was only 6.3% (3 cases); (2) no significant correlation between alexithymia and depression was noted; (3) expressiveness and conflict were significantly lower in families with alcoholics than in healthy families without alcoholics, although families with alcoholics do have strong conflicts. The results suggest the possibility that half of them forcefully suppress their conflicts, unconsciously deny the existence of alcoholics, and finally manifest secondary alexithymia.

Adult↗
PubMed1992

Burn-induced gastric mucosal hemodynamic disturbance in the rat. Role of platelet-activating factor.

The role of platelet-activating factor (PAF) as a mediator of gastric damage associated with burn injury was examined in the rat. Gastric mucosal hemodynamics was recorded continuously by means of laser-Doppler flowmetry and reflectance spectrophotometry. Burn injury induced prolonged hypotension and rapid-onset and long-lasting gastric mucosal hemodynamic derangement-that is, ischemia with congestion. This hemodynamic disturbance was significantly inhibited by CV-6209, a specific PAF antagonist. Elevated tissue levels of thiobarbituric acid reactants and pathologic changes in the gastric mucosa subsequent to burn injury were also significantly alleviated by the preadministration of CV-6209. These results strongly suggest a role of PAF as an important mediator of gastric damage after burn injury through its potent vasoactive effect on gastric microcirculation.

Animals↗
PubMed1992

[Aplastic anemia].

Explore the source record for details and available documents.

Anemia, Aplastic↗
PubMed1992

Automated microanalysis of creatinine by coupled enzyme reactions.

Hydrogen peroxide was generated from creatinine by the sequential enzyme reactions of creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase. Hydrogen peroxide was, in turn, used stoichiometrically for the condensation of 4-aminoantipyrine and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine catalyzed by horse-radish peroxidase, resulting in the formation of quinone dye with maximum absorbance at 546 nm. The optimized assay conditions for the enzymatic determination of creatinine in a HITACHI 7250 autoanalyzer was established. This system, which requires less than 5 microliters of sample, was found to be the most economical for laboratories equipped with autoanalyzers.

Autoanalysis↗
PubMed1992

[Platelet membrane glycoprotein V and clinical significance of plasma GPVf 1 level].

Thrombin hydrolyzes platelet membrane glycoprotein V (GPV) which has leucine rich repetitive modules specifically, and releases GPVf1 (fragment of N terminal in GPV). The GPV related antigen level in plasma will thus reflect activation of platelet in vivo. The ELISA assay to measure the concentration of GPV and GPVf1 in plasma using polyclonal anti-GPV antibody, was established. The concentration of GPV and GPVf1 in plasma by using polyclonal anti-GPV antibody was established. The concentration of GPV related antigen in plasma is significantly higher in patients with thrombosis and correlated well with thrombotic episodes. It was suggested that the measurement of plasma-GPV-related antigen level is a useful marker for the diagnosis of thrombosis or prethrombotic states.

Enzyme-Linked Immunosorbent Assay↗
PubMed1991

Functional Ca2+ channel produced by purified platelet membrane glycoprotein IIB-IIIA complex incorporated into planar phospholipid bilayer.

The ability of the platelet membrane glycoprotein (GP) IIb-IIIa complex to function as a Ca2+ channel was investigated by electrophysiological methods. The GPIIb-IIIa complex was purified with an electrically silent detergent, CHAPS, and reconstituted into liposomes. After incorporation of these liposomes to a planar phospholipid bilayer, Ba(2+)-permeable channel currents were detected. Since neither residual detergent nor dissociated GPIIb and IIIa produced any currents, the observed channel currents were attributed to the GPIIb-IIIa complex. These channel currents showed similar electrical properties with the Ca2+ channel previously described in platelet plasma membrane; a single channel conductance of approximately 10 pS in 53 mM Ba2+ solution and voltage-independency. It was concluded that the purified GPIIb-IIIa complex can act as a divalent cation-permeable channel in the artificial phospholipid bilayer.

Calcium Channels↗
PubMed1991

Electrophysiological evidence that glycoprotein IIb-IIIa complex is involved in calcium channel activation on human platelet plasma membrane.

The involvement of platelet glycoprotein (GP) IIb-IIIa complex in calcium channel activity on the plasma membrane was investigated using an electrophysiological approach. Plasma membrane vesicles were prepared from thrombin-stimulated platelets and incorporated into planar lipid bilayers. Voltage-independent Ca2+ channel currents with a conductance of about 10 pS (in 53 mM Ba2+) were observed, in membranes derived from thrombin-stimulated, but not unstimulated platelet membranes. These channel activities were markedly reduced by exposure of membranes to EGTA at 37 degrees C. This reduction was specifically related to the dissociation of the GPIIb-IIIa complex since preincubation of the membranes with a monoclonal antibody to the GPIIb-IIIa complex (AP-2) could protect the channel activities from the effect of EGTA. Thrombasthenic platelets, which lack the GPIIb-IIIa complex, showed impaired channel activities characterized by decreased open probability and lowered conductance states. Furthermore, when platelets were stimulated by thrombin in the presence of EGTA, AP2, or the synthetic peptide RGDS, to prevent fibrinogen binding to the GPIIb-IIIa complex, open probabilities of the channel currents in these membrane vesicles were also decreased. These results suggest that the GPIIb-IIIa complex is involved in platelet Ca2+ channel activation and that ligand binding to the complex during platelet activation may modify the activation of Ca2+ channels.

Amino Acid Sequence↗
PubMed1991

Molecular heterogeneity of platelet-activating factor (PAF) in rat glandular stomach determined by gas chromatography/mass spectrometry. PAF molecular species changes upon water-immersion stress.

The molecular heterogeneity of 1-alkyl-2-acetyl-sn-glycero-3-phosphocholine (alkylacetyl-GPC) and 1-acyl-2-acetyl-sn-glycero-3-phosphocholine (acylacetyl-GPC) in normal rat glandular stomach was studied by gas chromatography/mass spectrometry (GC/MS) and tandem mass spectrometry. The percentage compositions of the molecular species of 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC in the antrum were, respectively, 1-alkyl [16:0 (34%) and 18:0 (66%)]-2-acetyl-GPC and 1-acyl [16:0 (60%), 18:0 (14%) and 18:1 (26%)]-2-acetyl-GPC. The alkyl chain composition of 1-alkyl-2-acetyl-GPC was quite different from that of 1-alkyl-2-acyl-GPC in both the antrum and corpus, demonstrating a high degree of selectivity of alkyl chain utilization in PAF biosynthesis. The amount of 1-acyl-2-acetyl-GPC was much greater than that of 1-alkyl-2-acetyl-GPC. The molecular heterogeneity of 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC in the corpus was similar to that in the antrum. Water-immersion stress affected not only the amount of 1-alkyl-2-acetyl-GPC and 1-acyl-2-acetyl-GPC, but also their molecular heterogeneity in the antrum and corpus. Whereas the amounts of 1-hexadecyl-2-acetyl-GPC and 1-acyl [16:0, 18:0 and 18:1]-2-acetyl-GPC decreased markedly (to less than one-fifth) in the antrum after such stress for 1 hr, the amount of 1-octadecyl-2-acetyl-GPC increased markedly (up to 4-fold) in the corpus and severe lesions were observed after stress for 7 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Correlation between pain and synovitis in patients with internal derangement of the temporomandibular joint.

A correlation between pain scores by questionnaire and synovitis index via arthroscopic inspection was made in 28 patients with internal derangement of the temporomandibular joint (TMJ) with closed lock. A statistically significant but weak correlation was found between the visual analog scale of pain and the index of distribution of synovitis. However, in the questionnaire, pain on chewing had a positive correlation with both the intensity and distribution of synovitis in the TMJ. This study indicates that synovitis is one cause of TMJ pain in patients with closed lock.

Adult↗
PubMed1991

[Plasma cell tumor of the parieto-occipital bone; a case report].

Plasmacytoma originating in the cranial bone is a rare disease. A report is presented of a case of plasmacytoma originating in the parieto-occipital region. The patient was a 62-year-old male with palpation of a parieto-occipital mass as chief complaint. He showed no neurological deficit. Ig-G in the serum was 2240 mg/dl, and M-protein (n-type) was demonstrated in the serum. Bence-Jones protein was negative and bone marrow was normal. Skull X-ray showed osteolytic change in the parieto-occipital region. CT scan and MRI demonstrated a markedly enhanced mass extending from the epidural to the subcutaneous space at the parieto-occipital region. Common carotid angiography showed remarkable tumor stain flowing from the occipital artery, the superficial temporal artery, and the middle meningeal artery. Following embolization of the bilateral occipital artery, parieto-occipital horse shoe scalp incision was done. The tumor was elastic soft and bled easily around the margin of destroyed bone. Subtotal removal of the tumor was accomplished. The removed surgical specimen of the tumor was found to be plasmacytoma. The patient's postoperative course was favorable and no neurological deficit was found. Laboratory studies revealed a remarkable reduction of Ig-G in the serum to 1170 mg/dl. Six months after the operation, no signs of recurrence were seen on CT scan. Plasmacytoma originating in the cranial bone is so rare that only 18 cases have been reported to date. In these cases, laboratory studies have shown no evidence of anemia, Bence-Jones protein in urine, and abnormality of the bone marrow which are characteristic of multiple myeloma.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗