Purification and properties of a histidine decarboxylase from Tetragenococcus muriaticus, a halophilic lactic acid bacterium.

AIMS: A histidine decarboxylase from Tetragenococcus muriaticus, a halophilic histamine-producing bacterium isolated from Japanese fermented squid liver sauce, was purified to homogeneity, for the first time. METHODS AND RESULTS: The enzyme was purified 16-fold from cell-free extract by ammonium sulphate precipitation, anion exchange chromatography and hydroxyapatite chromatography. The pure enzyme consisted of two polypeptide chains with molecular mass of 28.8 and 13.4 kDa. The N-terminal amino acid sequences of these polypeptides highly correlated with those of the alpha- and beta-chains of other Gram-positive bacterial histidine decarboxylases. The optimum and stable pH for the enzyme was 4.5-7.0 and 4.0-7.0, respectively. This enzyme did not decarboxylate lysine, arginine, tyrosine, tryptophan and ornithine. The enzyme activity decreased with the addition of NaCl. At pH 4.8, the Vmax and Km values were 16.8 micromol histamine min-1 mg-1 and 0.74 mmol l-1, respectively. CONCLUSIONS: The very similar physiological properties of this enzyme and almost identical N-terminal amino acid sequences to those from other Gram-positive bacteria indicated that this enzyme may be evolutionally highly conserved among Gram-positive bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: Information on this enzyme could be useful for studying the mechanism of histamine accumulation in salted foods. In addition, the N-terminal amino acid sequence can be utilized to design oligonucleotide probes, which may prove valuable in the rapid monitoring of halophilic histamine producers in salted products.

Upper motor neuron predominant degeneration with frontal and temporal lobe atrophy.

The autopsy findings of a 78-year-old man mimicking primary lateral sclerosis (PLS) are reported. He showed slowly progressive spasticity, pseudobulbar palsy and character change, and died 32 months after the onset of symptoms. Autopsy revealed severe atrophy of the frontal and temporal lobes, remarkable neuronal loss and gliosis in the precentral gyrus, left temporal lobe pole and amygdala, mild degeneration of the Ammon's horn, degeneration of the corticospinal tract, and very mild involvement of the lower motor neurons. The anterior horn cells only occasionally demonstrated Bunina body by cystatin-C staining, and skein-like inclusions by ubiquitin staining. This is a peculiar case with concomitant involvement in the motor cortex and temporal lobe in motor neuron disease predominantly affecting the upper motor neuron.

[Significance of serum myosin light chain-1 level in neuroleptic malignant syndrome].

In Parkinson disease, the interruption of medication often results in neuroleptic malignant syndrome, which is caused by acute inhibition of the dopaminergic system. It is a serious question in the management of Parkinson disease, whether episode of pyrexia is derived from neuroleptic malignant syndrome or other origins. In this syndrome, muscle damage enhances serum titers of myogenic enzymes and proteins. Myosin light chain-1 (MLC-1), which is a small fragment of myosin, has been reported to show long lasting elevation compared with CK in neuromuscular diseases and cardiac infarction. Then, we evaluated the clinical significance of serum MLC-1 in six patients with neuroleptic malignant syndrome, i.e., four cases of Parkinson disease, one multiple system atrophy and one schizophrenia with acute administration of haloperidol. Muscle breakdown was observed by the elevation of serum MLC-1 titer, which sustained several days after normalization of serum CK titer. In two cases of Parkinson disease, high level of serum MLC-1 was observed in spite of normal body temperature, which suggested pre-clinical stage of neuroleptic malignant syndrome. Thus, we concluded that the estimation of serum MLC-1 is useful in those patients with high risk of neuroleptic malignant syndrome.

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.

[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)

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.

Chronic polyneuropathy and ulcerative colitis.

A case of chronic polyneuropathy associated with ulcerative colitis was reported. The patient was 57-year-old man who developed sensory disturbances and muscle weakness in four extremities along with the digestive symptoms of ulcerative colitis. Neurological examination revealed that sensory impairment in all modalities, muscular atrophy and weakness in the distal portions of all extremities and decreased or absent muscle stretch reflexes. Laboratory data included sedimentation rate 119mm/hour, CRP 4+, increased IgG and IgM. Lumbar puncture revealed normal CSF pressures, increased protein and IgG content with almost normal cell count. Nerve conduction velocity was delayed dominantly in sensory nerves. Sural nerve biopsy demonstrated degeneration of myelin sheath and decreased number of large fibers. Teased nerve study showed shortened internodal distances with myelin ovoids. These data together with the clinical course of this patient suggested that this peripheral neuropathy might be resulted from the common pathogenesis for ulcerative colitis which is considered as autoimmune disease.

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.

Evaluation of renal parathyroid hormone receptor function in myotonic dystrophy.

Endocrine abnormalities in myotonic dystrophy (MyD) reflect some of the multi-systemic involvement resulting from this disorder. One of these, abnormal insulin secretion, is considered to be caused by receptor dysfunction. Bone abnormalities, cataract and calcium transport defect suggest the abnormal calcium metabolism in MyD. The calcium metabolism is chiefly regulated by parathyroid hormone (PTH). An interest in the similarity between MyD and pseudohypoparathyroidism, which is a disorder of PTH receptor dysfunction, encouraged the authors to evaluate renal PTH receptor function from the responses of urinary adenosine 3',5'-monophosphate (cAMP) and phosphate excretion after administration of human PTH(1-34). The responses of cAMP were high in 3 cases, low in one case, but normal in the 4 other cases. The phosphaturic responses were elevated in 3 cases, reduced in 3 cases, and normal in 2 other cases. Since these abnormal responses closely mimic those in hypoparathyroidism, there may also be renal PTH receptor dysfunction in some cases of MyD. The results of the present study suggest another peptide hormone receptor defect, similar to insulin, which supports the hypothesis of generalised receptor dysfunction in MyD.

Tuberoinfundibular dopaminergic system and anterior pituitary dopamine receptor in Shy-Drager syndrome.

Tuberoinfundibular dopaminergic system (TIDA) together with anterior pituitary dopamine receptor was evaluated in 9 patients with Shy-Drager syndrome (SDS) through the responses of serum growth hormone (GH) and prolactin (PRL) to dopaminergic stimulation or dopamine receptor inhibition. A variety of abnormal responses of serum GH and/or PRL following the administration of these drugs suggests the TIDA involvement as well as the nigrostriatal system and moreover the different degeneration processes in each dopaminergic system in SDS.

Studies of circulating parathyroid hormone in man by a homologous amino-terminal specific radioimmunoassay.

A homologous radioimmunoassay specific for amino-terminal portion of human parathyroid hormone(PTH) was developed in order to study the clearance of biologically active species of the hormone in the circulation in man. Characterization of the assay system with synthetic analogues of human PTH (1-34) indicated that the carboxyl-terminal region of human PTH(1-34) is an important recognition site. Plasma amino-terminal PTH levels were less than 0.3 ng/ml in all of 35 normal subjects. The levels were elevated above 0.3 ng/ml in 15 of 24 patients with primary hyperparathyroidism. In 5 patients in whom the levels were determined before and after parathyroidectomy, the elevated levels were all normalized within 60 minutes after the removal of adenomata. The disappearance of exogenous human PTH(1-34) was studied after intravenous administration in 17 patients with hypoparathyroidism. A graphical analysis of the data disclosed two major components of the disappearance curve with estimated half-disappearance time of 3 and 28 minutes respectively, suggesting that multiple mechanisms are involved in the clearance of the peptide from the circulation. These results demonstrate usefulness of homologous radioimmunoassay for human PTH(1-34) in diagnosis and management of hyperparathyroidism, as well as in studying the clearance of amino-terminal portion of PTH which is known to represent biological activity.

Urinary adenosine 3',5'-monophosphate, circulating amino-terminal PTH (1--34) and carboxyl-terminal PTH in hypoparathyroidism.

In 38 patients with hypoparathyroidism, electrolytes, amino-terminal PTH(1--34) and carboxyl-terminal PTH in serum and urinary cyclic AMP were measured. Serum PTH(1--34) levels were low and C-PTH levels measured simultaneously in the same sera were low except one having a high level. In pseudohypoparathyroidism, serum C-PTH was elevated and in 1 of 2 patients serum PTH(1--34) was elevated. Urinary cyclic AMP was decreased in hypoparathyroidism and there was a positive correlation between urinary cyclic AMP and serum PTH in normal subjects and parathyroid dysfunctions. Responses of urinary cyclic AMP to PTH were better in hypoparathyroidism and less in primary hyperparathyroidism than normal subjects. These data suggest that measurements of serum PTH(1-34), C-PTH and urinary cyclic AMP are important in the diagnosis and pathophysiological classification of hypoparathyroidism.