Biomedical subjects
Publications and source records attributed to K Kashihara.
A patient with hepatitis C virus (HCV) infection developed neuropathy characterized by recurrent attacks of anesthesia, dysaesthesia, mild weakness and swelling of the right forearm. Serological examinations suggested an abnormal autoimmune state. HCV infection might produce neuropathy by inducing abnormal autoimmunity.
Autonomic functions were studied in 10 respiratory-support patients with motor neuron disease (MND) at its most advanced stage by means of hemodynamic function tests. The mean duration of disease was 83.4 months (SD 28.0, range 50-140 months). All the patients in this study had lost their ability to breathe spontaneously and were ventilated by respirator. Hemodynamic function tests were performed in 8 out of 10 patients. These patients showed exaggerated sympathetic vasomotor reflexes, increased reflex hypertension and tachycardia in response to the cold pressor test and increased response to administration of adrenaline. However, the responses to both the Aschner eyeball pressure test and injection of atropine were normal, indicating normal parasympathetic nervous system function. Plasma and urine levels of norepinephrine, epinephrine and their metabolites were almost normal in all 10 patients, as were serum dopamine-beta-hydroxylase levels. In patients with the most advanced stage of MND, hyperfunction of the adrenergic sympathetic nervous system was observed, and this was considered to be a symptom characteristic of MND.
A 74-year-old man presented sudden onset hoarseness and dysphagia. Two months before this event, he had developed arthralgia of the shoulders, elbows, hands and foot and pleuritis which had been alleviated by a treatment with prednisolone. On admission, the patient could not phonate nor swallow at all. His soft palate was elevated at the right side. The uvula moved left when the patient tried to speak. Laryngoscopic examination revealed the paralysis of right vocal cord. The erythrocyte sedimentation rate (79mm/1h), C-reactive protein (5.3mg/dl), rheumatoid factor (310 IU/ml) and Clq-binding immune complex (4.5 micrograms/ml) were elevated. Hepatitis C virus antibody titer was more than 10.8 IU/l. Anti-nuclear antibody was 1:20 (normal < 1:20) and anti-neutrophil cytoplasmic antibody (p-ANCA) was positive. Blood study also revealed the evidences of hemolytic anemia and hypoproteinemia. Hepatitis B virus markers, cryoglobulin, anti-ds DNA, anti-Sm, anti-RNP, anti-SS-A, anti-SS-B antibodies were negative. Magnetic resonance imaging of the brainstem was normal. A sural nerve biopsy revealed patchy demyelination of the fascicles. The teasing of nerve fibers showed segmental demyelination. Chest X-ray showed the interstitial pneumonia and pleuritis in the right lower lung. Otological examination revealed the bilateral secretory otitis media. A treatment with high dose prednisolone, ciclosporin and cyclophosphamide was partially effective. However we could not continue these medication because of the induction of liver damage. The patient died of multi-organ failure around a year after the emergence of aphonia and dysphagia. The autopsy specimen of the right vagus nerve showed the similar patchy damage of nerve fibers as was observed in the biopsied sural nerve. The present case was diagnosed as systemic rheumatoid vasculitis. The syndrome of aphonia and dysphagia due to paralysis of the unilateral soft palate and vocal cord is called Avellis syndrome. This syndrome has been reported mainly in relation with the infarction of lateral medulla. The present case shows that Avellis syndrome can be produced by mononeuritis of the vagus nerve.
We have previously isolated the rat serotonin (5-HT)1A receptor gene (G21Y2) and now report the expression and characterization of this receptor. The BamHI/Xbal fragment of this gene was cloned into Rc/RSV and stably transfected into HeLa cells by the calcium phosphate method. For determination of specific 5-HT1A receptor binding, [3H]8OH-DPAT was used as the radioligand and incubated with HeLa cell membranes. The cells expressed specific and saturable binding of [3H]8OH-DPAT with a Kd value of 0.3 nM and a Bmax value of 2 pmol/mg protein. GTP (50 microM) added to the incubation mixture increased the Kd value to 3 nM indicating that the expressed receptor is coupled to a G protein. The specific binding was inhibited by selective 5-HT1A partial agonists, such as buspirone, ipsapirone, gepirone, tandospirone, zalospirone and SUN8399 with Ki values of 1-30nM, whereas other neurotropic drugs except for spiperone (Ki = 46 nM) and nemonapride (Ki = 2.3 nM) were effective only at concentrations of more than 100 microM. The potencies of these compounds to inhibit [3H]8OH-DPAT from its specific binding sites were similar to their affinities determined in rat hippocampus binding studies. These data suggest that the expressed receptor is a 5-HT1A-type similar to 5-HT1A receptors in the rat hippocampus.
The coding sequence of the rat m3, m4 and m5 subtypes of muscarinic acetylcholine receptor (mAChR) genes was amplified by the polymerase chain reaction (PCR), cloned, and expressed in the murine fibroblast (B82) cell line. Sequencing of the cloned genes revealed some nucleotide differences when compared with the DNA sequence published in the literature. When the different sequence appeared in only one clone obtained by PCR, it was considered an error of the polymerase. The overall error frequency in the 25 cycles of PCR with either Taq polymerase or Replinase was 1 nucleotide in 1,692 base pairs. In order to evaluate the different nucleotide sequence from a PCR product as an error or as an allelic variant, at least three different clones were sequenced. The cloned genes were each stably expressed in a B82 cell line and pharmacologically evaluated. The affinity of the different antagonists to the muscarinic receptor subtypes was determined by [3H](-)MQNB/ligand inhibition experiments. In the m3, m4 and m5 transfected cells, carbachol appeared to stimulate [3H]inositol monophosphate (IP1) accumulation. Carbachol, at 3 microM, appeared to suppress the forskolin-stimulated cAMP formation in the m4 transfected cells. These findings suggest these mAChRs amplified by PCR, cloned, and expressed in the B82 cell lines exhibit the pharmacological characteristics of the muscarinic receptor subtypes.
We evaluated T/M ratios and T2 values of 6 malignant lymphomas and 8 squamous cell carcinomas in the head and neck in order to differentiate these two entities. T/M ratios were calculated by dividing intensity of tumor by that of muscle in same slice images. T2 values were calculated from T2-weighted images and proton-weighted images. Statistical difference of T/M ratios was found between malignant lymphomas and squamous cell carcinomas, but no difference of T2 values was seen between two groups. T/M ratio was considered to be a useful and quantified index for evaluation of head and neck tumor.
We report a patient with idiopathic hypoparathyroidism associated with unilateral calcification of the basal ganglia and contralateral choreic movements. A 66-year-old woman was admitted to our hospital because of involuntary movements of the left limbs. Two years before the present admission, she had operations for bilateral cataracts. Eight months before admission, she had an onset of severe carpal spasms and pain in both arms and legs. These symptoms improved after one month's rest in a hospital. About a month before admission, she noted progressive difficulty in using her left hand, followed by difficulty in walking due to the abnormal involuntary movement of the left lower limb. Two weeks before admission her carpal spasms appeared again, bilaterally. On admission, she was alert. The general physical examination was normal. Neurological examination revealed choreic movements in the left hand, arm, leg and neck, and grimacing of the left face. She also complained of the spasms and pain in her hands, dysarthria and shortness of the breath. Chvostek and Trousseau signs were positive. Laboratory examination revealed marked decrease in serum calcium level (2.57 mEq/ml) and increase in inorganic phosphorus level (6.40 mEq/ml). Serum level of parathyroid hormone was less than 10 pg/ml. Ellthworth-Howard test was positive, in that the infusion of parathyroid hormone (100 u) elicited a marked increment of the urinary excretions of phosphorus and cAMP. X-ray examination of the spine revealed ossification of the posterior longitudinal ligament in the cervical region. CT-scans of the brain revealed calcification in the region of right globus pallidus and putamen.(ABSTRACT TRUNCATED AT 250 WORDS)
Repeated administration of amphetamine or methamphetamine (MAP) causes behavioral sensitization in animals. Recently, several studies have revealed that in vivo release of dopamine from presynaptic nerve terminals of mesotelencephalic dopamine neurons is enhanced when sensitized animals are rechallenged with a psychostimulant. The present study investigated the effect of co-administration of SCH 23390 (a selective D1 dopamine receptor antagonist) or YM-09151-2 (a selective D2 dopamine receptor antagonist) prior to each MAP injection for 14 days on dopamine efflux in the striatal perfusates using in vivo dialysis. After 3 months drug abstinence, MAP challenge alone produced augmented stereotypy in the MAP group, but not in the control, the SCH 23390 + MAP or the YM-09151-2 + MAP group. In parallel with this behavioral observation, the degree to which dopamine efflux increased following the MAP challenge was significantly greater in the MAP group than that in the control, SCH 23390 + MAP group and the YM-09151-2 + MAP groups. While dopamine efflux after MAP challenge did not differ between the control and the YM-09151-2 + MAP group, it was greater in the SCH 23390 + MAP group than the control group. These results indicate that both D1 and D2 dopamine receptors play a role in the formation of behavioral sensitization, but with different mechanisms.
The effect of MK-801 at a dose of 0.5 mg kg-1, i.p., on methamphetamine-induced (MAP; 4 mg kg-1, i.p.) dopamine (DA) release was examined in the striatum of freely moving rats using an in-vivo microdialysis method. Combined treatment of MK-801 with MAP did not modify the MAP-induced increase in extracellular DA levels or the decrease in 3,4-dihydroxyphenylacetic acid levels. These findings suggest that MK-801 fails to modify the acute effect of MAP on DA release in the striatum. The blocking effect of MK-801 on the development of MAP-induced behavioral sensitization is unlikely to be mediated by DA neurons.
The effect of methamphetamine (MAP) on the efflux of endogenous dopamine (DA) in the medial frontal cortex of freely moving rats was evaluated by a microdialysis technique. The injection of MAP at 4 mg/kg, i.p., increased the extracellular levels of DA and decreased the levels of 3,4-dihydroxyphenylacetic acid significantly. Although the changes were smaller than those observed in the striatum, the direction and time course were similar. MAP increases the efflux of DA in the medial frontal cortex.
The effect of MK-801 on striatal dopamine (DA) release was investigated by using an in vivo microdialysis technique in the freely moving rat. Systemic injection of MK-801 (0.25, 0.5, 1, 2 mg/kg, i.p.) reduced the extracellular level of DA significantly and produced no change in the level of 3,4-dihydroxyphenylacetic acid. The behavioral observation, recorded simultaneously, revealed that MK-801, with smaller doses, produced ipsilateral circling toward the side with the dialysis probe. At larger doses, MK-801 predominantly evoked ataxia. These findings indicate that the behavioral effect of MK-801 may not be mediated via the release of DA.
Using a probe derived from the human 5-HT1A receptor gene (G-21), a strongly hybridizable clone was identified from a rat genomic DNA library. This clone (G21Y2) had an overall deduced amino acid sequence that was 88% homologous with that of the human 5-HT1A receptor. There was only an 18% and 19% amino acid homology with the rat 5-HT1C and 5-HT2 receptors, respectively. The G21Y2 appears to be an excellent candidate for the rat 5-HT1A receptor gene. As this manuscript was being prepared a report by Albert et al. (13) was published in which a probe to the hamster beta 2-adrenergic receptor was used to identify a rat genomic (Clone D) that demonstrated a sequence that was similar to G21Y2.
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Serial photographs of an enlarging fundal hemorrhage were taken in a 44-year-old man with a subarachnoid hemorrhage. Although clipping surgery was done successfully 17 hours after onset, the patient developed impaired vision on the third postoperative day. Funduscopic examination can document the exact moment when enlarging subhyaloid hemorrhage extends into the vitreous cavity.
Thirteen patients with acoustic neuroma were studied on a 1.5 T superconductive magnetic resonance (MR) imager. Acoustic neuromas appeared as lower signal intensity than the surrounding brain stem on T1 weighted image (W.I.), and as higher signal intensity on T2 W.I.. Axial and coronal sections of T1 W.I. were very useful in observing the tumor in the auditory canal and in investigating the anatomical relations of the tumor and the surrounding structures. MR imaging is very excellent examination to make early diagnosis of the acoustic neuroma and preoperative anatomical evaluation.
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