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Biomedical subjects

K Mizoguchi

Publications and source records attributed to K Mizoguchi.

At least 19 recordsLinked to original sources

L-threo-3,4-dihydroxyphenylserine, a noradrenaline precursor, inhibits dopamine release and metabolism in the rat striatum in vivo.

The effect of L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) on dopamine (DA) release and metabolism in the striatum was studied in freely moving rats by intracerebral microdialysis techniques. The DA level as well as the levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid were significantly decreased 140 min after the administration of L-threo-DOPS (50 mg/kg intraperitoneally). The results suggest that L-threo-DOPS inhibits the release and metabolism of DA in the striatum.

Animals

Eating and drinking cause increased dopamine release in the nucleus accumbens and ventral tegmental area in the rat: measurement by in vivo microdialysis.

Dopamine (DA) release was simultaneously monitored in the nucleus accumbens (NAC) and ventral tegmental area (VTA) of conscious rats using in vivo microdialysis. During dialysis perfusion, rats were allowed access to food or water for 20 min following a 36 h food and water deprivation period. DA release increased significantly in the NAC and VTA in response to eating and drinking. The increases in both regions continued until 20-60 min after the end of the feeding or drinking session. These results show that the mesolimbic DA pathway is activated in response to ingestive behavior, and that DA release occurs in the cell body (A10) region as well as in the mesolimbic DA nerve terminals.

Animals

Expression cloning of a sheep adreno-ferredoxin using the polymerase chain reaction.

In addition to the selective amplification of cDNA from total RNA by the PCR method, the distinctive properties of ferredoxin-expressing colonies can be used for cloning a ferredoxin cDNA. This strategy for cloning and expressing cDNA in E. coli was applied to a sheep adreno-ferredoxin. The expressed sheep ferredoxin showed a spectral pattern typical of [2Fe-2S] proteins. The amino acid sequence deduced from the DNA sequence showed that the mature form of sheep ferredoxin consists of 128 amino acid residues. This rapid and simple method for cloning and expressing cDNA can be applied to other ferredoxins.

Adrenal Cortex

Stress induces neuronal death in the hippocampus of castrated rats.

Whereas loss of CA3 neurons in the hippocampus of monkeys which died of stress ulcers suggests that some structural changes may occur, there is no direct evidence that shows stress-induced irreversible changes of neurons. When rats were orchidectomized (castrated) and stressed by restraint and immersion in water for 15 min/day for 30 days, significant loss of hippocampal CA3 and CA4 neurons was observed. Furthermore, primary cultured hippocampal neurons survived shorter when treated with corticosterone. This neuronal loss was prevented by simultaneous administration of testosterone in vivo and in vitro. These findings indicate that stress can contribute to neuronal degeneration associated with hypogonadal conditions such as aging.

Androstanols

IgM M-protein in a patient with sensory-dominant neuropathy binds preferentially to polysialogangliosides.

A 77-year-old man presented sensory-dominant neuropathy associated with IgM M-protein reacting with various gangliosides. The M-protein bound to gangliosides with polysialosyl residue, such as GD1b, GD3, GT1b, GT3, GQ1b, and GQ1c. In addition, GD1a, GM3 and LM1, having a terminal monosialosyl epitope, were also recognized. Previously, Ilyas et al. described a similar case in which sensory symptoms were associated with IgM M-protein reacting with gangliosides containing a disialosyl group, such as GD3, GD1b, and GT1b, but not GM3 and GD1a. It is suggested that the reactivity of IgM M-protein with polysialogangliosides may be associated with the pathogenesis of sensory-dominant neuropathy.

Aged

[A case of chronic toluene poisoning with myopathic changes].

We reported a 27-year-old man, who had inhaled toluene vapor for 11 years and developed both polyneuropathy and myopathy. He gradually developed progressive muscular weakness in the limbs 2 months after the last inhalation and became nonambulant. Neurological examination revealed distal dominant muscular weakness and hypoactive deep tendon reflexes, especially in the legs. The cranial nerves were intact and neither sensory disturbances nor cerebellar signs were observed. Laboratory studies demonstrated mildly elevated serum CK value, but serum electrolytes and urinalysis were normal. Electromyogram showed a neurogenic pattern in the limbs and also a myogenic in the gastrocnemius muscle. Motor nerve conduction velocities were delayed in the limbs. The sural nerve biopsy specimens showed demyelination, myelin avoids, and axonal swelling compatible with toxic neuropathy. The muscle biopsy of the gastrocnemius revealed necrotic muscle fibers, vacuolated muscle fibers, phagocytosis, a disordered intermyofibrillary network, and small group atrophy on light microscopy. On electron microscopy, two outstanding findings were observed; the first, dilatation and proliferation of the membrane system, and the second, appearance of irregular membrano lamellar structures and vacuoles associated with abnormal membrane system. These histological findings suggest that toluene may affect directly the membrane system of muscle fibers and consequently induce rhabdomyolysis.

Adult

[A case of carcinosarcoma of the lung].

A 78-year-old man was admitted to our hospital with cough and left anterior chest pain. Chest X-ray examination on admission revealed a tumor shadow in the left upper lobe. Malignant tumor cells were observed on histopathological examination of a specimen obtained by bronchoscopic biopsy. Radiotherapy was performed but was not effective, and the patient died of respiratory failure 4 months after admission. Autopsy revealed a 15 cm diameter tumor with marked local invasion tendency without distant metastasis. Microscopically, the tumor consisted partly of squamous cell carcinomas, and partly of fibrosarcomas, composed of spindle cells and osteo-chondrosarcoma. The tumor was therefore diagnosed as carcinosarcoma. Immunohistochemical examination showed positive keratin and EMA staining only in the squamous cell carcinoma component of the tumor.

Aged

Noradrenaline release in the rat amygdala is increased by stress: studies with intracerebral microdialysis.

The effects of immobilization and tail-pinch stress on extracellular noradrenaline (NA) release in the amygdala were studied in freely moving rats with intracerebral microdialysis techniques. After collection of basal levels of NA (2.63 +/- 0.26 pg/50 microliters/20 min), the rat was exposed to either immobilization stress or tail-pinch stress for 20 min. Immobilization and tail-pinch stress increased NA release to 250 and 243% of basal levels, respectively and the elevation of NA release was observed for 60 min and 40 min after release from stress, also respectively. These data suggest that microdialysis is a useful way to study extracellular NA release in the amygdala and that NA neurons in this region are activated by both immobilization and tail-pinch stress.

Amygdala

Psychological stress-induced increases in noradrenaline release in rat brain regions are attenuated by diazepam, but not by morphine.

By measuring levels of noradrenaline (NA) and its major metabolite, 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MHPG-SO4) in the hypothalamus, amygdala and locus coeruleus region, we investigated the effects of diazepam 5.0 mg/kg, morphine 6.0 mg/kg, or naloxone at 5.0 or 10 mg/kg injected SC immediately before stress exposure, on increases in NA release caused by psychological stress. Psychological stress, wherein rats were exposed to emotional responses which were displayed by other electrically shocked rats, significantly increased MHPG-SO4 levels in the three brain regions examined and elevated plasma corticosterone levels. Both increases in brain MHPG-SO4 levels and elevations of plasma corticosterone levels induced by stress were attenuated significantly by diazepam but neither by morphine nor by naloxone. MHPG-SO4 levels in the hypothalamus and amygdala in the morphine-stress group were significantly higher than those in the saline-stress group. These findings suggest that psychological stress, in which an emotional factor is predominantly involved, causes increases in NA release in these brain regions examined and that these increases are attenuated only by diazepam, in contrast to the previous report, where increases in brain NA release caused by immobilization stress are attenuated not only by diazepam but also by morphine and are enhanced by naloxone.

Amygdala

Consultation-liaison psychiatric approach for school-refusal students in Hiratsuka City, Kanagawa Japan.

In current school health care programs, it is necessary to check not only the physical condition but also for mental disorders caused by changes of sociocultural, economic or environmental conditions and, in fact, the relative importance of the latter is increasing every year. Taking these changes into consideration, the Kanagawa Prefectural Joint Teacher-Visiting School Doctor Mental Health Committee started various activities aimed at raising the psychiatric ability of school doctors in 1983. In parallel with the activities of the Kanagawa Prefectural committee, the Hiratsuka Medical Society established the Hiratsuka City Joint Teacher-Visiting School Doctor Mental Health Committee in May 1985. In April 1988, as an extention of the activities of the Hiratsuka Committee, a counseling class for non-attending junior high school students was set up. The purpose of this class was, to provide an opportunity for school, families and medical organization to exchange information and to collaborate to provide more effective treatment and education to cope with recent advanced and prolonged cases of school refusal. In addition to Hiratsuka City, Fukuoka is engaged in practical activities under the direction of a joint committee led by the local Medical Society.

Adaptation, Psychological

Direct evidence of conditioned fear-elicited enhancement of noradrenaline release in the rat hypothalamus assessed by intracranial microdialysis.

Inescapable footshock stress produced marked increases in noradrenaline (NA) release, which was assessed by intracranial microdialysis, in the hypothalamus of conscious rats. Emotional stress, without physical stimuli (replacement to the environment where the rats had received footshock previously), also increased hypothalamic NA release. These results suggest that foodshock stress caused increases in NA release and this activation of NA neurons appears to be reinstated simply by re-exposure to the environment previously associated with shock.

Animals

Decreased serum levels of IgE and IgE-binding factors in individuals infected with HTLV-I.

The cell surface expression of low-affinity Fc epsilon receptor (Fc epsilon RII), which is identical to CD23, and the serum levels of IgE binding factors (IgE BFs), a soluble form of Fc epsilon RII, and IgE were investigated in HTLV-I-infected individuals, and the results were compared with those for HTLV-I-negative controls. The occurrence of Fc epsilon RII+ mononuclear cells did not differ among the blood samples from the HTLV-I-infected groups; however, the levels of serum IgE BFs were significantly decreased (P less than 0.001) in patients with adult T cell leukaemia (ATL), compared with HTLV-I-negative controls. The serum IgE levels were also significantly decreased in these groups, including cases of ATL (P less than 0.001) and HTLV-I-associated myelopathy (P less than 0.05), and HTLV-I carriers (P less than 0.05), as compared with HTLV-I-negative controls. Since cases of strongyloidiasis or filariasis are frequently found among HTLV-I-infected individuals in Japan, these results may explain in part their defective defence mechanisms for parasites. The possible involvement of IgE BFs in the development of immune deficiency state in HTLV-I infection is also discussed.

Adult

Antipurified-protein-derivative antibody in tuberculous pleural effusions.

Using ELISA, we studied anti-PPD antibody values in 31 tuberculous and 39 carcinomatous pleural effusions. Mean ODI values of anti-PPD IgG, IgA and IgM antibodies in tuberculous pleural effusions were higher than those in carcinomatous pleural effusions (p less than 0.01 in IgG and IgA, p less than 0.05 in IgM antibodies). We also analyzed the detected antigens in PPD and BCG whole cell fraction recognized by IgG antibody in tuberculous pleural effusions. Among heteromolecular components, the antigen band from 25 to 40 Kd region was most frequently stained. This antigen was heat-stable, contained sugar components, and included no disulfide bonds.

Adolescent

A case of ornithine transcarbamylase deficiency with acute and late onset simulating Reye's syndrome in an adult male.

A 15-year-old male was admitted to the hospital because of a disturbance of consciousness. He was in good mental and physical condition until the previous day, when he vomited and experienced a reduction of consciousness. He was brought to the hospital the day following the onset of symptoms. On admission the patient was stuporous. Neurological focal signs were not demonstrated. Computed tomographic (CT) scanning on admission showed no definite abnormality. Cerebrosprinal fluid had no pleocytosis. At this time, Reye's syndrome was suspected because of the acute change of consciousness and the presence of hyperammonemia. The disturbance of consciousness progressed and he became comatose on the day following admission. CT scanning showed that the suprasellar, ambient and quadrigeminal cisterns could almost not be detected and the bilateral ventricles were narrowed. The plasma aminogram demonstrated an elevation of alanine, lysine, glutamine, glutamic acid, aspartate and proline. Ketonuria was negative, but the urinary excretion of orotic acid was markedly increased. This data was indicative of the existence of an ornithine transcarbamylase (OTC) deficiency. The patient was died on the third day after hospitalization. The OTC activity in the liver was 10% of normal. Activities of other enzymes in the urea cycle were within normal limits. It is unusual that the symptoms of the enzyme deficiency occurred, both acutely and late at an adult age, as in this case. This case demonstrates that OTC deficiency should be considered in the differential diagnosis of hyperammonemia of adult onset.

Adolescent

Benign exertional headaches induced by swimming.

A 57 year-old woman with benign exertional headaches induced by swimming is described. The headaches were bilateral, throbbing and occurred while swimming. She had a history of occasional similar headaches while straining during bowel movements. The neurological examination and computed tomographic (CT) scanning were normal. The electroencephalogram (EEG) had diffuse alpha activity, and no symptoms or significant changes of the EEG were triggered by the Valsalva maneuver, which causes a transient increase in cranial blood pressure and alters the normal vascular balance. She has stopped swimming and since then has never had a headache. No medications were needed. This case demonstrates that not all headaches are triggered by intracranial lesions. Benign exertional headaches should also be considered in the differential diagnosis of this type of headache in the elderly.

Female

Effects of stress, non-stress cyclicity on hypothalamic noradrenaline release in rats.

The effects of continuous stress and intermittent stress at short intervals on rat hypothalamic noradrenaline (NA) release were assessed by measuring the levels of a principal metabolite of NA, 3-methoxy-4-hydroxy-phenylethyleneglycol sulfate (MHPG-SO4) in male Wistar rats. The rats were exposed to one of five restraint stress conditions, unstressed (control), six 15 min intermittent stress periods (interspersed with 18 min non-stress periods), three 30 min intermittent stress periods (interspersed with 45 min non-stress periods), 90 min continuous stress period or 180 min continuous stress period. The 15 min intermittently stressed rats had significantly larger increases in hypothalamic MHPG-SO4 than the single 90 min and 180 min continuously stressed rats, while the 30 min intermittently stressed rats were significantly different from only the 180 min continuously stressed rats. In a comparison of the 15 min and 30 min intermittently stressed rats, which had the same total duration of stress exposure; the 15 min group had larger increases in MHPG-SO4 levels than the 30 min group. This study provides supporting evidence for the role of stress cyclicity in determining the extent of stress-induced NA release from the hypothalamus.

Animals

Effects of progesterone on concentrations of monoamines in hypothalamic areas and plasma prolactin levels in rats.

The role of progesterone to increase prolactin (PRL) secretion on the first estrous day in pubertal rats was compared with its role in adult cyclic rats. The first estrus was induced by the administration of pregnant mare serum gonadotrophin (5 IU) at 28 days of age. A subcutaneous administration of 2.5 or 7.5 mg of progesterone/100 g body wt significantly increased the concentration of plasma PRL in pubertal rats within 4 hr. The PRL level obtained after progesterone administration was greater than that in similarly treated adult rats. The concentration of dopamine in the arcuate nucleus-median eminence (ARC-ME) in pubertal rats significantly decreased after a lower dosage of progesterone was administered, but no change was found in the preoptic area concentration. In adult estrous rats, the concentration of dopamine in the ARC-ME showed a tendency to decrease after the administration of a larger dose of progesterone (7.5 mg/100 g body wt). No change was observed in the concentrations of indoleamines in the preoptic area and ARC-ME after the administration of progesterone in both pubertal and adult rats. The concentrations of dopamine in the preoptic area and ARC-ME were lower in pubertal rats than in adults. The concentration of 5-hydroxyindole acetic acid and the ratio of 5-hydroxyindole acetic acid to 5-hydroxytryptamine in the ARC-ME were higher in pubertal rats than in adults. These results indicate that progesterone causes a greater increase in tonic PRL secretion in pubertal rats than in adult rats and that a lower hypothalamic dopamine activity and a higher serotonin activity in pubertal rats may account for these differences.

Animals