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Biomedical subjects

K Tada

Publications and source records attributed to K Tada.

At least 253 records · Page 14Linked to original sources
PubMed1990

Identification of a common mutation in patients with medium-chain acyl-CoA dehydrogenase deficiency.

Medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is one of the most common recessively inherited metabolic diseases in man. We have studied fibroblast cultures obtained from three patients with MCAD deficiency by sequencing the entire coding region of MCAD mRNA. A single A to G nucleotide replacement which resulted in lysine329-to-glutamic acid329 substitution of the MCAD protein was identified in all cultures. Furthermore, this point mutation was present in 91% (31 of 34) of mutant MCAD alleles, indicating that the majority of cases with MCAD deficiency are caused by this type of mutation.

Acyl-CoA Dehydrogenase↗
PubMed1990

Enzymatic diagnosis of 3-hydroxy-3-methylglutaryl-CoA lyase deficiency with high-performance liquid chromatography.

A new non-radiochemical method for determination of 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) lyase is described. Acetyl-CoA, the product of the enzymatic reaction, is separated from the substrate by high-performance liquid chromatography and is quantified. The mean 3-hydroxy-3-methylglutaryl-CoA lyase activity in control fibroblasts was 7.8 +/- 2.1 (SD) nmol/min per mg protein, and its apparent Km value was 77.8 +/- 14.3 microM (R/S mixture) with a calculated Vmax of 12.4 +/- 2.2 nmol/min per mg protein. Using this method, we could easily differentiate a patient with 3-hydroxy-3-methylglutaryl-CoA lyase deficiency from control subjects.

Acetyl Coenzyme A↗
PubMed1990

Effect of phosphorylation on 68 KDa neurofilament subunit protein assembly by the cyclic AMP dependent protein kinase in vitro.

The effect of phosphorylation by cyclic AMP dependent protein kinase on the assembly of the core-forming 68 KDa neurofilament subunit protein (NF-L) was studied in vitro by fluorescence energy transfer and electron microscopy. Phosphorylation of unassembled NF-L in a low ionic strength buffer by cyclic AMP dependent protein kinase led to the incorporation of 1-2 phosphate groups/mole protein. Assembly of this phosphorylated NF-L was inhibited significantly; compared to non-phosphorylated NF-L, the critical concentration of phosphorylated NF-L was raised by greater than 30-fold. Assembled NF-L filaments could also be phosphorylated by cyclic AMP dependent protein kinase indicating that the sites were accessible. Phosphorylation of NF-L in the filamentous state induced their disassembly. The results suggest that phosphorylation by cyclic AMP dependent protein kinase is a possible means to modulate the assembly state of NF-L.

Animals↗
PubMed1990

Bone blood flow after spinal paralysis in the rat.

The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow.

Animals↗
PubMed1990

Mosaicism of mitochondria in mitochondrial myopathy: an electronmicroscopic analysis of cytochrome c oxidase.

Electron microscopic histochemistry was applied to the study of cytochrome c oxidase activity in each mitochondrion of biopsied muscles from four patients with mitochondrial myopathy [one case of fatal infantile mitochondrial myopathy, one case of myoclonus epilepsy associated with ragged-red fibers (MERRF), and two cases of mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS)]. In the patient with fatal infantile mitochondrial myopathy, intercellular heterogeneity of mitochondria was recognized. In the three patients with either MERRF or MELAS, cytochrome c oxidase activity was segmentally changed from positive to negative within single muscle fibers. In the two patients with MELAS, small groups of positive-stained mitochondria were located among negative-stained mitochondria in the negative segment of a few muscle fibers. These findings revealed that there were heterogeneous populations of normal and abnormal mitochondria intracellularly or intercellularly within the muscles of these patients.

Adult↗
PubMed1990

Acute autonomic and sensory neuropathy: a case report.

A female patient with acute autonomic and sensory neuropathy is described. Urinary disturbance developed rapidly and was followed by orthostatic syncope, absence of lacrimation, salivation and sweating, and sensory impairment. Muscle strength had been consistently normal despite diffuse muscular atrophy. Marked decrease in the number of small myelinated and unmyelinated fibres was revealed in biopsied sural nerve. Eighteen months after the onset, her autonomic symptoms have partially improved.

Acute Disease↗
PubMed1990

Aged-onset Kienböck's disease.

Kienböck's disease with onset after 50 years of age was studied. Of 127 patients with Kineböck's disease seen over the past 30 years, the cases of 15 (12 female, 3 male) were analyzed. The average age of onset was 58.3 years. Five specimens were obtained operatively in which necrosis of the lunate bone mixed with empty lacunae was identified, as was bony remodelling. Ulnar variance in the aged diseased group (group A) was smaller than that of the aged control group (group C). Moreover, it was noteworthy that the variance among aged controls (group C) was higher than among the young controls (group D). The metacarpal index of the patients with aged-onset Kienböck's disease was markedly lower than that of the young. Considering the increase of ulnar variance with age, the persistence of minus variance and the presence of osteoporosis might make the lunate bone susceptible to injury.

Age Factors↗
PubMed1990

Type 4 renal tubular acidosis (subtype 2) in a patient with methylmalonic acidaemia.

A 10-month-old male infant with vitamin B12 non-responsive methylmalonic acidaemia is reported. Laboratory results revealed hyperkalaemic, hyperchloraemic, metabolic acidosis with slight azotaemia. The urinary pH decreased (below 5.5) to compensate for acidaemia. Levels of plasma renin activity and plasma aldosterone concentration were low. The renal biopsy showed tubulo-interstitial nephritis. We suggested the diagnosis of type 4 renal tubular acidosis, subtype 2, i.e. hyporeninaemic hypoaldosteronism. We suggest that chronic renal disease may be a common complication of methylmalonic acidaemia.

Acidosis, Renal Tubular↗
PubMed1990

Secondary amyloidosis in glycogen storage disease type Ib.

We observed the development of generalized amyloidosis in a girl with glycogen storage disease type Ib (GSD-Ib) who showed neutropenia, neutrophil dysfunction and recurrent infections. Renal and thyroid biopsies showed secondary amyloidosis, characterized by the presence of potassium permanganate sensitive Dylon positive deposits in glomeruli, renal vessels and thyroid interstitium. Immunohistochemistry showed that the deposits were composed of amyloid A (AA) protein. Possibly neutrophil abnormalities are involved in the pathogenesis of amyloidosis.

Amyloidosis↗
PubMed1990

Restoration of axial and appendicular bone volumes by h-PTH(1-34) in parathyroidectomized and osteopenic rats.

Effects of h-PTH(1-34) were histomorphometrically evaluated in both cancellous and cortical bone tissues of axial and appendicular skeletons of parathyroidectomized and osteopenic rats. Osteopenia was induced by hemicordotomy immobilization and by estrogen depletion as a result of ovariectomy. The rats received intramuscular injections of 50 units (15 micrograms) of h-PTH(1-34) six times weekly during weeks 11 through 18 of the experiment. Significant restoration of cancellous and cortical bone volumes was observed in axial and appendicular skeletons of animals treated with h-PTH(1-34). The stimulatory effects of h-PTH(1-34) on osteoid surface, independent of eroded surface, in cancellous and cortical bone tissues, were clearly observed histomorphometrically. Mineralizing surface, mineral apposition rate and bone formation rate in cancellous bone tissues were markedly increased by h-PTH(1-34). It should be noted that h-PTH(1-34) increased trabecular thickness, but did not increase trabecular number. In conclusion, h-PTH(1-34) stimulated bone formation independent of bone resorption, and restored cancellous and cortical bone volumes in parathyroidectomized and osteopenic rats.

Animals↗
PubMed1990

Somatosensory evoked potentials in acute renal failure: effect of parathyroidectomy.

Effects of acute renal failure (ARF) on somatosensory evoked potentials (SEP) were studied in rats. Cervical and cortical SEPs were measured both before and after bilateral ureteral ligation. A significant augmentation of amplitudes and an increase in latencies of the cortical SEP were observed in ARF. The peripheral nerve conduction velocities were unchanged. Serum parathyroid hormone (PTH) levels in uremic rats were significantly elevated after the bilateral ureteral ligation. In previously parathyroidectomized rats, the bilateral ureteral ligation had no effects on amplitudes of SEP or serum PTH levels.

Acute Kidney Injury↗
PubMed1990

An acute form of tyrosinemia type I with multiple intrahepatic mass lesions.

The acute form of tyrosinemia type I usually causes severe hepatocellular dysfunction. We report a 4-month-old infant with hepatosplenomegaly, ascites, and multiple intrahepatic mass lesions mimicking hepatoma. A marked increase of serum alpha-fetoprotein (97.6 micrograms/ml) and multiple small low-density lesions in the liver demonstrated by computed tomography suggested the presence of hepatoma. The liver specimens obtained at laparatomy showed mixed nodular cirrhosis with fatty metamorphosis. Serum levels of tyrosine (6.6 mg/100 ml) and methionine (5.9 mg/100 ml) were increased. Urinary organic acid analyses disclosed increased excretions of succinylacetone (1,330 mg/g creatinine) and delta-amino-levulinic acid (113.6 mg/g creatinine). Histological abnormalities and biochemical evidences led to the correct diagnosis. This case emphasizes the need for complete investigations of puzzling cases and warns against undue reliance on noninvasive imaging techniques.

Amino Acid Metabolism, Inborn Errors↗