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Biomedical subjects

Y Konagaya

Publications and source records attributed to Y Konagaya.

At least 19 recordsLinked to original sources
PubMed1992

The mechanism of perturbation in monoamine metabolism by L-dopa therapy: in vivo and in vitro studies.

In the cerebrospinal fluid of the patients with Parkinson's disease treated with L-DOPA, L-3-O-methyldopa was the major metabolite of administered L-DOPA. Using a dopaminergic cell model, clonal rat phenochromocytoma PC 12h cells, and by microdialysis of the rat striatum it was proved that L-3-O-methyldopa was taken up into monoamine neurons by transport system specific for aromatic L-amino acids and inhibited transport of L-DOPA and other amino acids competitively. L-3-O-Methyldopa depleted allosteric regulation of the biopterin cofactor on activity of tyrosine hydroxylase, the rate-limiting enzyme of catecholamine synthesis. Depletion of the allostery may perturb the buffer action of endogenous L-DOPA synthesis that stabilizes dopamine level in the brain. By these mechanisms L-3-O-methyldopa may reduce clinical effectiveness of administered L-DOPA and be involved in wearing-off phenomenon. L-DOPA inhibited the activity of tryptophan hydroxylase and thus serotonin synthesis, which may be related to psychiatric side-effects in the patients under L-DOPA therapy.

Aged↗
PubMed1992

Quadriceps myositis.

A young woman with slowly progressive muscular weakness and atrophy localized in both thighs is reported. Laboratory, electromyographic and histological findings suggested that the patient suffered from chronic myositis with a background of autoimmune disorder. Quadriceps myositis is a rare condition. The previously reported cases of this disease in the literature are reviewed.

Adult↗
PubMed1992

[CSF acetylcholinesterase activity in central neurological diseases involving cholinergic systems].

The enzymatic activity of acetylcholinesterase (AchE) in the cerebrospinal fluid (CSF) is considered to be a marker of central cholinergic neuron integrity. Then, we evaluated CSF AchE activity in 90 cases of neurological diseases involving cholinergic system and their related disease, and 28 control cases without central organic lesions or abnormal findings in routine CSF study. AchE activity was evaluated according to Ellman's method using acetylthiocholine iodide as a substrate and tetraisopropyl-pyrophosphoramide, a specific inhibitor of butyrylocholinesterase. CSF AchE of Alzheimer type dementia (AD/SDAT, N = 12: 21.9 +/- 4.7 nmol/ml/min) showed no significant change from those of both control group (22.1 +/- 3.9) and vascular dementia (9: 21.7 +/- 6.7). In extrapyramidal diseases, reduction of the activity was observed in Huntington's chorea (HC, 4: 16.3 +/- 1.4) and progressive supranuclear palsy (PSP, 4: 17.6 +/- 1.7), whereas normal activity was shown in Parkinson's disease (PD, 19: 22.5 +/- 4.6), dentatorubropallidoluysian atrophy (DRPLA, 4: 22.6 +/- 4.2) and striatonigral degeneration (SND, 4: 20.4 +/- 4.3). In olivopontocerebellar atrophy (OPCA, N = 16), we disclosed reduced CSF AchE activity (15.8 +/- 2.4) which had significant correlations with the atrophy of the pontine base (r = 0.6017, p less than 0.02) and cerebellar vermis (r = 0.5450, p less than 0.05) in MRI. AchE activity in cerebellar cortical atrophy (CCA, 5: 20.6 +/- 2.2) remained within the control values. Normal activity was demonstrated in both amyotrophic lateral sclerosis (6: 24.3 +/- 7.3) and spinal muscular atrophy (4: 22.9 +/- 3.9).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1991

[Abnormality of hypothalamic dopaminergic system in neuro-degenerative diseases--evaluation of alpha-melanocyte-stimulating hormone-like immunoreactivity in cerebrospinal fluid].

Dopaminergic neuron controls CNS functions such as meso-limbic, striato-nigral and tubero-infundibular systems. The purpose of the present study is the evaluation of the hypothalamic dopaminergic neuron activity in neuro-degenerative disorders. alpha-melanocyte-stimulating hormone (alpha-MSH) is synthesized in the arcuate nucleus and lateral part of the hypothalamus, and its secretion is under the inhibitory control of the dopaminergic neuron both in the hypothalamus and pituitary. alpha-MSH-like-immunoreactivity (alpha-MSH-LI) in CSF is thought to be representative to the dopaminergic neuron activity in the hypothalamus. We therefore evaluated CSF levels of alpha-MSH-LI in spinocerebellar degenerations and extrapyramidal diseases. The subjects are 11 patients with Parkinson's disease, 16 with Shy-Drager syndrome (SDS), 16 with cerebellar cortical atrophy, 3 with Machado-Joseph disease, 3 with dentato-rubro-pallido-luysian atrophy and 2 with Huntington's disease as well as 24 controls. All patients with Parkinson's disease were administered levodopa and carbidopa. CSF was sampled through lumbar puncture in the morning. After the centrifugation, supernatant of CSF was stored at -40 degrees C until used. alpha-MSH in CSF was extracted by Rainero's method and measured by RIA. alpha-MSH-LI levels in control was 23.9 +/- 2.6 pg/ml (mean +/- SD). The significant elevation was observed in Parkinson's disease (40.3 +/- 7.5, p less than 0.001) and SDS (42.3 +/- 9.4, p less than 0.001). The levels showed not significant correlation with age, duration of illness or severity of autonomic disorder. Most of other diseases demonstrated the levels within normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Magnetic stimulation study in mirror movements.

A young man with congenital mirror movements was studied by non-invasive magnetic stimulation. Radiological examination showed no craniocervical or pituitary abnormality except for mild atrophy of the right hippocampus. Magnetic stimulation of the motor cortex caused large amplitudes in the ipsilateral hand muscles, indicating the possibility of functional disorder in the motor pathways from the motor cortex to muscles in the upper extremities.

Adult↗
PubMed1990

Neural control of glutamine synthetase activity in rat skeletal muscles.

The mechanism of glutamine synthetase induction in rat skeletal muscle after denervation or limb immobilization was investigated. Adult male rats were subjected to midthigh section of the sciatic nerve. At 1, 2, and 5 h and 1, 2, and 7 days after denervation, rats were killed and denervated, and contralateral control soleus and plantaris muscles were excised, weighted, homogenized, and assayed for glutamine synthetase. Glutamine synthetase activity increased approximately twofold 1 h after denervation in both muscles. By 7 days postdenervation enzyme activity had increased to three times the control level in plantaris muscle and to four times the control level in soleus muscle. Increased enzyme activity after nerve section was associated with increased maximum velocity with no change in apparent Michaelis constant. Immunotitration with an antiglutamine synthetase antibody suggested that denervation caused an increase in the number of glutamine synthetase molecules in muscle. However, Northern-blot analysis revealed no increase in the steady-state level of glutamine synthetase mRNA after denervation. A mixing experiment failed to yield evidence for the presence of a soluble factor involved in regulating the activity of glutamine synthetase in denervated muscle. A combination of denervation and dexamethasone injections resulted in additive increases in glutamine synthetase. Thus the mechanism underlying increased glutamine synthetase after denervation appears to be posttranscriptional and is distinct from that of the glucocorticoid-mediated glutamine synthetase induction previously described by us.

Animals↗
PubMed1990

[Pentose phosphate pathway in neuromuscular diseases--evaluation of muscular glucose 6-phosphate dehydrogenase activity and RNA content].

There have been several reports concerning elevated glucose 6 phosphate dehydrogenase (G6PDH), the rate-limiting enzyme of pentose phosphate pathway (PPP), in experimental muscle disturbances. PPP produces ribose, a substrate of RNA, and NADPH which is a cofactor of fatty acid synthesis. PPP also has a role of by-path pathway of glycolysis. Then, we evaluated G6PDH activity and RNA content in biopsied quadriceps muscle. The subjects were muscles from 23 neurogenic amyotrophy, 54 myopathy including 19 progressive muscular dystrophy (PMD), and 10 controls whose muscle was obtained at orthopedic surgery. Neurogenic amyotrophy consisted of 12 amyotrophic lateral sclerosis (ALS), 4 spinal muscular atrophy and 7 peripheral nerve disorders. Myopathy were 3 Duchenne dystrophy, 2 congenital muscular dystrophy, 8 limb-girdle type dystrophy, 6 facio-scapular +-humeral muscular dystrophy, 6 myotonic dystrophy, 6 mitochondrial myopathy, 5 endocrinological myopathy, 3 hypokalemic myopathy, 8 polymyositis and 4 other inflammatory myopathy. The assays of G6PDH and RNA were performed after Glock's and Fleck's methods, respectively. The control values were 3.6 +/- 0.8 nmol formed NADPH/mg protein/min (M +/- SD) in G6PDH and 0.69 +/- 0.17 micrograms/mg non-collagen protein in RNA. Most cases of PMD, as well as some cases of ALS, hyperthyroidism, mitochondria hypokalemic myopathy, inflammatory myopathy showed increased values (beyond M + 2SD of control) both in G6PDH and RNA. There were significant positive correlations between G6PDH activity and RNA content in PMD and motor neuron disease. Myotonic dystrophy showed normal values in both G6PDH and RNA. Half number of cases of mitochondrial myopathy demonstrated increased G6PDH alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Studies on enzyme activities relating to amino acid mobilization in biopsied muscles].

We evaluated glutamine synthetase (GS) and alanine aminotransferase (GPT) activities in biopsied muscle from 40 cases of various neuromuscular diseases. GS and GPT catalyze the synthesis of glutamine and alanine, respectively, from amino acids derived in part from the breakdown of muscle proteins. The subjects were 7 cases of muscular dystrophy; 1 Duchenne type (DMD), 3 limb-girdle type, 2 facioscapulohumeral type (FSH), 1 Fukuyama type (FCMD); and 1 myotonic dystrophy (MyD); 5 mitochondrial myopathies; 11 inflammatory myopathies including 6 polymyositis and 3 myopathy associated with collagen disease; 5 endocrinological myopathies including 2 periodic paralysis; and, 11 cases of neurogenic amyotrophies [4 amyotrophic lateral sclerosis (ALS), 4 spinal progressive muscular atrophy (SPMA) and 3 other types]. Control subjects were 8 patients with thigh operations. Biopsied muscle was homogenized and assayed for GS activity by the method of Smith et al.; GPT was assayed by commercial kit. Protein was assayed by the method of Lowry et al. Enzyme activities between mean -2SD and mean +2SD of controls were considered to be the normal range. GS activity in control subjects was 28.22 +/- 7.13 (mean +/- SD) nmol glutamine formed/mg protein/hr. Fifteen of 40 cases showed increased enzyme activity, including DMD and FCMD, the acute phase of polymyositis, and periodic paralysis. GPT activity in controls was 16.56 +/- 4.05 IU/mg protein. Sixteen of 40 patients showed increased enzyme activity: FCMD, FSH, MyD, inflammatory and endocrinological myopathy, and ALS. On the other hand, mitochondrial myopathy showed significantly decreased activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[An MRI study of hereditary spinocerebellar degenerations].

We evaluated magnetic resonance image (MRI) in 21 cases of hereditary spinocerebellar degenerations (SCD) of autosomal dominant trait. By the discriminant formula based on size of the cerebellar vermis and ventral pons, which was reported in our previous study, the patients were classified into three types. Group 1 included the cases with atrophies in the vermis and pons; OPCA type. Group 2 showed vermian atrophy and less significant atrophy in pons; LCCA type. And Group 3 was no significant atrophies both in vermis and pons. Cases in Group 1 were furthermore divided into two groups according to width of the midbrain tegmentum. Group 1A, with normal midbrain tegmentum, was consisted of five cases. Four cases were diagnosed as Menzel type OPCA. Another case showed various clinical symptoms and relatively mild atrophies for his duration of illness. His family members were classified to Group 3. Seven cases in Group 1B showed reduced midbrain tegmentum. Four cases showed ataxia, spasticity, ocular symptoms, bladder dysfunction and amyotrophy with or without fasciculation, and they seemed to be a special type of SCD mimicking Joseph disease. One case showed bulging eyes, ocular movement palsy and dystonia. However, his sister manifested only ataxia with very mild ocular movement disorder. Their MRI demonstrated severe atrophies in the cerebellum, pons and afferent cerebellar peduncli, and this pedigree was thought to be Menzel type OPCA with various associated disorders. Another case was clinically diagnosed as dentate-rubro-pallido-luysian atrophy. Group 2 was consisted of 6 cases who were clinically diagnosed as Holmes type LCCA. MRI demonstrated medial dominant cerebellar atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[MRI findings of the tongue in neurodegenerative diseases with bulbar sign].

We examined the magnetic resonance image (MRI) of the tongue in cases of amyotrophic lateral sclerosis (ALS), bulbo-spinal muscular atrophy (SBMA) and Shy-Drager syndrome (SDS) with sleep apnea. ALS case with severe bulbar disorder showed atrophic, irregularly margin tongue with increased signal intensity in T1-weighted MRI. ALS with less severe bulbar disorder demonstrated mixed hyperintensity and normointensity areas in the tongue. ALS without lingual symptoms showed increased intensity of tongue which suggested subclinical involvement of lingual muscle. BSMA case also showed atrophic tongue with diffusely increased signal intensity. SDS case with sleep apnea was revealed to have round shaped tongue without increased signal intensity, but his tongue fell into the posterior oral cavity, indicating hypotonus of genioglossus muscle. We concluded that MRI of the tongue is useful to determine the bulbar symptoms due to lower neuron disorder or not.

Aged↗
PubMed1990

[MRI study of three siblings of suspicious Sjögren-Larsson syndrome].

We report the characteristics of high field magnetic resonance imaging (MRI) of three siblings with hereditary spastic paraplegia (HSP), probably of autosomal recessive inheritance. The proband was a 25-year-old woman who manifested slowly progressive spastic paraplegia, mental deficit, decayed teeth since her childhood. The siblings of the proband, 29-year-old woman and 27-year-old man, also showed the same clinical course as hers, and the symptoms are more severe in elder siblings. The proband solely had ichthyosis on her neck and lower thighs, which suggested Sjögren-Larsson syndrome. Sagittal and transverse slices of high field MRI (1.5T), T2-weighted (SE 2800/90) and T1-weighted (500/15) images were obtained. The cerebral atrophies were observed in the frontal and the parietal lobes, especially at the precentral and superior frontal gyri, whereas the occipital lobes were relatively spared. The atrophies of motor cortex seemed to be responsible for the disorder of voluntary movement. T2WI demonstrated a diffuse hyperintensity in the cerebral white matter, which suggested demyelination. T2WI also showed remarkable hypointensities in the globus pallidus, putamen, and thalamus. The degenerative involvement in these regions was also suspected. These abnormal intensities, both hyper- and hypo-intensities, were stronger in elder siblings, which indicated the intensity changes to be of progressive nature. Severe atrophy or hypoplasia of corpus callosum was also observed, however the cingulate gyri could be confirmed. We were not able to detect the callosal disconnection syndrome, because of their severe mental impairment. Spinal cord was slender and its degenerative changes were suggested. The high field MRI of a HSP family showed the extensive abnormal findings of the central nervous system in this HSP family, such as cerebral motor area, extrapyramidal system, corpus callosum, and spinal cord.

Adult↗
PubMed1989

Human PTH(1-34) infusion test in differential diagnosis of various types of hypoparathyroidism: an attempt to establish a standard clinical test.

To introduce a simple procedure and reliable diagnostic criteria for parathyroid hormone (PTH) infusion test, 128 patients with either pseudo- (PsH) or idiopathic hypoparathyroidism (IdH) and 25 normocalcemic controls were studied. Incremental responses of urinary cyclic AMP and phosphate to 20 micrograms (67 U) or 30 micrograms (100 U) of human PTH(1-34) were assessed by using simple parameters of urinary excretion rates of the two substances. The results are summarized as follows. (1) PTH dose-cyclic AMP response relation suggests that 100 U of PTH is more appropriate than 67 U as a standard test dose for adults. (2) By presenting the magnitude of cyclic AMP response as either net increase or fold increase during 1 h after 100 U of PTH infusion, we can differentiate PsH type I from others without overlap. (3) Differentiation between PsH and IdH or normocalcemic subjects by phosphaturic response is less clearcut than that made by cyclic AMP response whatever indices and criteria are used. Thus it seems difficult to diagnose PsH type II merely based on the discrepancy between cyclic AMP and phosphaturic responses to exogenous PTH. (4) The test results are essentially similar in the examinations performed before and during vitamin D therapy. However, when the magnitude of phosphaturic response is expressed as net increase during 2 h after PTH, it tends to be enhanced after vitamin D therapy in patients with PsH compared to the response before therapy.

Adolescent↗
PubMed1989

[Correlation of clinical course with MRI findings in olivo-pontocerebellar atrophy and late-cortical cerebellar atrophy].

We quantitatively analyzed 1.5 T MRI in 36 cases of sporadic spinocerebellar degeneration (SCD) and 30 control cases without intracranial lesions, using graphic analyzer. SCD consisted of 21 olivo-ponto-cerebellar atrophy (OPCA) and 15 late cortical cerebellar atrophy (LCCA). There was negative correlation between vermian size and the duration of illness both in OPCA (r = 0.8960, p less than 0.001) and LCCA (r = 0.7756, p less than 0.01), but the progression rate in OPCA was three times greater than that in LCCA. LCCA was suggested the preclinical vermian atrophy by the statistical regression study. In OPCA, the duration of illness also revealed significant correlations with atrophy of ventral pons (r = 0.8308, p less than 0.001) and also cerebellar hemisphere (medial hemisphere; r = 0.7278, p less than 0.001. lateral hemisphere; r = 0.6039, p less than 0.01). OPCA showed diffuse atrophy of cerebellar hemisphere, whereas LCCA showed medial dominant atrophy. OPCA demonstrated significant correlation between the fourth ventricle dilatation and the duration of illness (r = 0.6005, p less than 0.01). A discriminant study significantly separated OPCA, LCCA and control each other by sizes of ventral pons and cerebellar vermis (p less than 0.001). In T2 weighted MRI, 10 cases out of 14 LCCA did not show hypointensity in dentate nucleus in spite of normal appearance in the other portions usually decreased intensity. The dentate nucleus of OPCA showed a significant atrophy. The incidence of putaminal hypointensity in OPCA was significantly greater than that of control group (chi-square = 6.476, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Nuclear glucocorticoid receptor binding in L6 skeletal muscle cells in culture.

Mechanisms underlying glucocorticoid hormone actions on skeletal muscle remain incompletely understood. This problem may be amenable to solution with a simple cell culture system in which the hormonal environment can be controlled. In this report, we demonstrate that the L6 muscle cell line may provide such a system. These cells, which possess many morphological and functional characteristics of skeletal muscle, originate as mononuclear myoblasts, which fuse to form multinucleated myotubes. L6 myoblasts and myotubes contain an intracellular glucocorticoid receptor that has binding parameters and ligand specificity similar to those of glucocorticoid receptors of classical glucocorticoid target tissues. A major advantage of the use of cultured cells is ease of isolation of myonuclei that display specific glucocorticoid receptor binding. L6 muscle cells should provide a valuable model system for further studies of the mechanisms of glucocorticoid hormone actions on muscle.

Animals↗
PubMed1988

Dexamethasone regulates glutamine synthetase expression in rat skeletal muscles.

The regulation of glutamine synthetase expression by dexamethasone was studied in rat skeletal muscles. Daily administration of dexamethasone caused striking enhancement of glutamine synthetase activity in plantaris, soleus, and diaphragm muscles. Northern blot analysis revealed that the dexamethasone-mediated increase of glutamine synthetase activity was associated with dramatically increased levels of glutamine synthetase mRNA. Both glutamine synthetase activity and mRNA levels were significantly elevated in plantaris muscle at 0.5 mg.kg-1.day-1 of dexamethasone, a dose that approximates endogenous corticosteroid levels in animals under severe stress. Quantification of changes in glutamine synthetase mRNA on the basis of total mRNA (by oligo dT hybridization) also revealed a major increase in glutamine synthetase mRNA. Dexamethasone was without effect on beta-tubulin mRNA levels, indicating that glutamine synthetase induction is not part of a global response to glucocorticoids. Dexamethasone treatment resulted in only an approximately 15% increase in glutamine synthetase activity in heart; there was no change in glutamine synthetase mRNA level in this tissue. Thus glucocorticoids regulate glutamine synthetase gene expression in rat skeletal muscles.

Animals↗
PubMed1987

Increased serum myosin light chain 3 level in neuromuscular diseases.

A radioimmunoassay for human skeletal muscle myosin light chain 3 (MLC-3) was developed. The serum level of MLC-3 was evaluated in 143 patients suffering from neuromuscular diseases. Increased MLC-3 level was observed in muscular dystrophies. There were significant positive correlations between serum levels of MLC-3 and creatine kinase (CK) in Duchenne and limb-girdle type muscular dystrophy, but the regression lines were different. Patients with neurogenic amyotrophy, especially amyotrophic lateral sclerosis, also showed elevated MLC-3 levels with or without high CK, and the frequency of increase in MLC-3 was greater than that of CK. The results of the present study suggest that circulating MLC might be a useful marker for muscle breakdown not merely in myopathies but in neurogenic disorders.

Circadian Rhythm↗
PubMed1987

Evaluation of the endogenous glucocorticoid hypothesis of denervation atrophy.

We studied the effects of oral administration of RU38486, a potent and selective glucocorticoid antagonist, on muscle weight, non-collagen protein content, and selected enzyme activities (choline acetyltransferase, glucose-6-phosphate dehydrogenase, and glutamine synthetase) following denervation of rat skeletal muscle. Neither decreases in muscle weight, protein content, and choline acetyltransferase activity, nor increases in the activities of glucose-6-phosphate dehydrogenase and glutamine synthetase were affected by RU38486. These data do not support the hypothesis that denervation atrophy results from enhanced sensitivity of muscle to endogenous glucocorticoids.

Animals↗