Removal and recovery of phosphate and ammonium as struvite from supernatant in anaerobic digestion.

Removal of phosphorus and nitrogen is required to prevent eutrophication problems in lakes and enclosed coastal seas. And recovery of phosphorus from wastewater has been attracting attention because of lack in phosphorus resources in the near future. In this study, reaction kinetics and design parameters of struvite production are experimentally investigated by using basic reaction type and a draft-tube type reactors. Struvite production rate, which is a very important parameter in reactor design and efficiency estimation, is formulated in an equation consisting of a rate constant (k2), and magnesium, phosphate and ammonium concentrations. The value of k2 is shown to be increased with struvite concentration and mixing intensity in the reactor. The developed equation is applied to the results obtained from the draft-tube type reactor experiments and verified for its applicability. High struvite concentration of 10-25% is maintained in the draft-tube reactor experiments. 92% removal and recovery efficiency with effluent phosphorus concentration of 17 mg/L is achieved under the conditions of 4 minutes reaction time, pH of 8.5 and Mg/P molar ratio of 1.1.

Human biotin-containing subunit of 3-methylcrotonyl-CoA carboxylase gene (MCCA): cDNA sequence, genomic organization, localization to chromosomal band 3q27, and expression.

3-Methylcrotonyl-CoA carboxylase (MCCase; EC 6.4.1.4) is a mitochondrial biotin enzyme and plays an essential role in the catabolism of leucine and isovalerate in animals, bacterial species, and plants. MCCase consists of two subunits, those that are biotin-containing and non-biotin-containing. The genes responsible for these subunits have been isolated in soybean, Arabidopsis thaliana, and tomatoes, but not in mammals. In humans, MCCase deficiency has been thought to be a rare metabolic disease, but the number of patients with MCCase deficiency appears to be increasing with a wide range of clinical presentations, some that result in a lethal condition and others that are asymptomatic. In this report, we have isolated and carried out chromosomal mapping of the gene for the biotin-containing subunit (A subunit) of the human MCCase gene, MCCA. The cDNA predicts an open reading frame coding for a 725-amino-acid protein with mitochondrial signal peptide, biotin carboxylase, and biotin-carrier domains. The gene is composed of at least 19 exons and covers more than 70 kb of sequence on band q27 of chromosome 3. MCCA was abundantly expressed in mitochondria-rich organs, such as the heart, skeletal muscles, kidney, and liver. In exon 13, we observed a His/Pro polymorphism at codon 464 (an A to C transition at nucleotide position 1391 in the cDNA sequence). Then, we determined the DNA sequences of the 5' untranslated region and entire coding regions in two patients with MCCase deficiency, but no sequence substitution was detected, suggesting that the gene mutations might be in the non-biotin-containing subunit (B subunit) gene, MCCB, in these patients.

Management of acute metabolic decompensation in maple syrup urine disease: a multi-center study.

BACKGROUND: Therapeutic modalities in acute metabolic decompensation in maple syrup urine disease (MSUD) are variable, and outcomes of each therapeutic measure have been known only individually. Factors that affect neurological outcome are not clear. METHODS: A questionnaire was sent throughout Japan to each pediatrician treating any of the 42 MSUD patients. RESULTS: Necessary information was available for 13 patients through the questionnaire, and through a publication for one patient. In nine of the 14 patients episodes of metabolic decompensation developed in the neonatal period. In the other five, the onset of disease was delayed until infancy or later. In the nine patients with neonatal onset, a pretreatment level of plasma leucine greater than 40 mg/100 mL or a duration of altered level of alertness longer than 10 days was associated with a poor neurological outcome. The therapeutic measures employed included intravenous infusion of glucose and electrolyte solution or hypertonic glucose and electrolyte solution, exchange transfusion, peritoneal dialysis, a large dose of thiamine and intravenous hyperalimentation. All patients had survived the episodes and were alive at the time of the survey. Five of the nine patients with neonatal onset have developed neurological sequelae to varying degrees. Episodes of metabolic decompensation in infancy or thereafter did not affect, or only minimally affected, the neurological outcome. CONCLUSION: Therapeutic goals to improve neurological outcome are to shorten the duration of the altered level of consciousness, and to minimize the peak plasma leucine level as much as possible.

Primary systemic carnitine deficiency is caused by mutations in a gene encoding sodium ion-dependent carnitine transporter.

Primary systemic carnitine deficiency (SCD; OMIM 212140) is an autosomal recessive disorder characterized by progressive cardiomyopathy, skeletal myopathy, hypoglycaemia and hyperammonaemia. SCD has also been linked to sudden infant death syndrome. Membrane-physiological studies have suggested a defect of the carnitine transport system in the plasma membrane in SCD patients and in the mouse model, juvenile visceral steatosis. Although the responsible loci have been mapped in both human and mouse, the underlying gene has not yet been identified. Recently, we cloned and analysed the function of a novel transporter protein termed OCTN2. Our observation that OCTN2 has the ability to transport carnitine in a sodium-dependent manner prompted us to search for mutations in the gene encoding OCTN2, SLC22A5. Initially, we analysed the mouse gene and found a missense mutation in Slc22a5 in jvs mice. Biochemical analysis revealed that this mutation abrogates carnitine transport. Subsequent analysis of the human gene identified four mutations in three SCD pedigrees. Affected individuals in one family were homozygous for the deletion of a 113-bp region containing the start codon. In the second pedigree, the affected individual was shown to be a compound heterozygote for two mutations that cause a frameshift and a premature stop codon, respectively. In an affected individual belonging to a third family, we found a homozygous splice-site mutation also resulting in a premature stop codon. These mutations provide the first evidence that loss of OCTN2 function causes SCD.

Spontaneous regression of hepatocellular carcinoma: a case report.

We report a hepatocellular carcinoma that appeared to undergo spontaneous regression twice. On June 5, 1995, two hepatocellular carcinomas were detected by ultrasonography in a 72-year-old woman. On July 1, 1995, the tumor in the lateral segment had increased in size from 2.0 cm to 3.2 cm in 27 days, and the level of alpha-fetoprotein (AFP) had increased from 743 to 1300 ng/ml. On September 22, 1995, one tumor appeared as a typical hypervascular lesion on contrast-enhanced computed tomography. It was 3.9 cm in size and located in the posterior segment. The other was a 3.9-cm cystic mass located in the lateral segment. The tumor in the posterior segment was treated with an emulsion of epirubicin and lipiodol administered via the posterior branch of the right hepatic artery and percutaneous ethanol injection. The tumor in the lateral segment was kept under observation because it was avascular, had regressed to 2.0 cm in size, and the patient's AFP level had decreased to 237 ng/ml by December 5, 1995. By February 21, 1996, the AFP level had increased again to 105,340 ng/ml, and by March 22, 1996, the latter tumor had increased in size to 3.8 cm. However, it later regressed again to 1.6 cm, and the AFP level decreased spontaneously to 7 ng/ml. From the changes in the contrast-enhanced computed tomographic images, and the level of AFP, we cannot rule out the possibility that the spontaneous regression might have been caused by the tumor's rapid growth.

Suppression of presynaptic calcium influx by metabotropic glutamate receptor agonists in neonatal rat hippocampus.

Mechanisms of presynaptic inhibition by metabotropic glutamate receptor (mGluR) agonists were investigated in neonatal rat hippocampal CA1 region using the optical recording technique recently developed. Following selective loading of presynaptic terminals with a fluorescent Ca2+ indicator dye rhod-2 AM, changes in Ca2+ signals and the corresponding field excitatory postsynaptic potentials (EPSPs) induced by single electrical stimuli to the Schaffer collateral-commissural (SCC) pathway were recorded simultaneously. Application of a mGluR agonist, 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD; 100 microM) or (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (trans-ACPD; 100 microM), reversibly reduced both the field EPSP and the presynaptic Ca2+ transient, and the quantitative relationship between them was quite similar to that observed during application of Cd2+, a non-selective Ca2+ channel blocker, or in a Ca(2+)-free solution. Application of 4-aminopyridine (4-AP; 1 mM), a blocker of certain subtypes of voltage-dependent K+ channels, significantly inhibited the 1S,3R-ACPD effect. Application of DCG-IV, a novel mGluR2/mGluR3-selective agonist, suppressed field EPSPs only slightly even at a high dose (3 microM). These results suggest that activation of presynaptic mGluR different from mGluR2/mGluR3 suppresses the action potential-triggered Ca2+ influx, probably via 4-AP-sensitive mechanisms, and thereby reduces glutamate release in neonatal rat hippocampal CA1 region.

[Late phase II trial of high-dose l-leucovorin and 5-fluorouracil in advanced colorectal carcinoma. l-Leucovorin and 5-FU Study Group (Japan Eastern Group)].

A multicenter cooperative study was conducted from Dec. 1992 to April 1994 to evaluate the clinical efficacy of high-dose l-leucovorin (l-LV) and 5-fluorouracil (5-FU) treatment in 76 patients with advanced colorectal carcinoma. Treatment consisted of intravenous bolus injection of 5-FU (600 mg/m2) 1-hour after the initiation of a 2-hour infusion l-LV (250 mg/m2), 6 weekly treatments were administered followed by a two-week rest. These treatment were repeated until progressive disease or intolerable toxicity. Seventy patients were evaluated for response. Responses were the following: PR 21, NC 29, PD 20 and the overall response rate was 30%. Grade 4 hematological side-effect was observed in three cases, and severe diarrhea in one case. These data suggested that high-dose l-LV and 5-FU was effective for advanced colorectal carcinoma but showed some hematological toxicity, and a further investigation should be carried out.

[High-dose leucovorin and 5-fluorouracil in advanced gastric and colorectal cancer. High-Dose Leucovorin and 5-FU Study Group].

A multicenter cooperative study was conducted from June 1988 to July 1989 to evaluate the clinical efficacy of high-dose dl-Leucovorin (dl-LV) and 5-FU treatment in 61 cases of advanced gastric and colorectal cancer. The administration schedule was a 2-hour infusion of dl-LV (500 mg/m2) and an IV bolus of 5-FU (600 mg/m2), given 1 hour after the beginning of LV infusion. Patients (pts.) were treated q week x 6 then evaluated for response. Thirty one gastric cancer pts. were divided into two groups; nine pts. treated with 30 min. infusion of 5-FU, and the remaining 23 pts. treated with IV bolus. PR was obtained in 2/9 (22.2%) and in 7/22 (31.8%) of the first and second group, respectively. An overall response rate was 9/31 (29%). Thirty colorectal cancer pts. were divided the same: 13 pts. treated with 30 min. infusion of 5-FU and the remaining 17 pts. treated with IV bolus. PR was obtained in 2/13 (15.4%) and in 7/17 (41.2) of the first and second groups, respectively. An overall response rate was 9/30 (30%). Median survival time for the gastric cancer group was 9.4 months, and for the colorectal cancer group was 13.6 months. Toxicity was within acceptable limits. Toxic effects included diarrhea, stomatitis, anorexia and myelohypoplasia. Our data suggests that high dose LV and 5-FU seems to be a very promising combination and warrants a further investigation.

Evaluation of the possible role of glucose, carnitine, coenzyme Q10 and steroids in the treatment of Reye's syndrome using the margosa oil animal model.

Glucose and steroids have been used in the treatment of children with Reye's syndrome, while carnitine and coenzyme Q10 have been the subject of some recent studies which suggest that these agents may have a role in the treatment of Reye's syndrome and Reye-like syndrome due to margosa oil poisoning. Because of the paucity of causes of Reye's syndrome seen at any one centre, the clinical variability of the disease, and limited knowledge of definite aetiologic factors, controlled clinical trials are not easy to carry out or to interpret in human cases. These caveats were overcome by evaluation of these four treatment modalities in an established margosa-oil-induced animal model of Reye's syndrome. Effectiveness of the treatment modalities was determined from clinical response and histopathologic parameters (grading of light microscopic fatty changes and ultrastructural changes in the hepatocytes). Results show that carnitine per se produces a small improvement in survival, but statistically, more significant benefit is seen with glucose administration. Carnitine plus 10% dextrose appears to produce better results. Evaluation of coenzyme Q10 and carnitine on histopathologic parameters in the liver after a sublethal dose of margosa oil showed no obvious ameliorating effect on liver pathology. Steroids (dexamethasone/methylprednisolone) had no beneficial effects in reducing mortality, affecting glycogen storage or lipid accumulation. Changes in the mitochondria, ribosomes and endoplasmic reticulum were unaltered from the groups treated with margosa oil alone. While glucose and carnitine supplements appear to be beneficial, the other modes of therapy do not seem to hold much promise in the treatment of Reye-like syndrome in the margosa-oil-induced animal model.

Segmented heterochromia in black scalp hair associated with iron-deficiency anemia. Canities segmentata sideropaenica.

A newly recognized disorder of black scalp hair is characterized by the irregularly alternating segmentation of hair into dark and light bands. A 15-year-old girl had segmented heterochromic scalp hair in association with iron-deficiency anemia. The clinical and laboratory investigations support the view that low serum iron levels play a critical role in reducing eumelanogenesis and in the possible failure of melanin transfer. The segmented heterochromic hair recovered completely after iron supplementation, which coincided with increased eumelanogenesis in the recovered hair. This clinical experience indicated participation of iron in the kinetics of melanogenesis within the follicular melanocytes.

Inhibition of mitochondrial functions by margosa oil: possible implications in the pathogenesis of Reye's syndrome.

Margosa oil (MO), a fatty acid-rich extract of the seeds of the neem tree and a reported cause of Reye's syndrome, has been used in the induction of an experimental model of Reye's syndrome in rats. It has been reported that MO causes a decrease in in vivo mitochondrial enzyme activity similar to that seen in Reye's syndrome. We have attempted to uncover some of the biochemical mechanisms of MO's toxicity by examining its effect in vitro on isolated rat liver mitochondria. Male rat liver mitochondria were isolated by centrifugation; oxygen uptake, reduced forms of cytochrome b, c + c1, a + a3, and flavoprotein, intramitochondrial concentrations of acetyl coA, acid-soluble coA, acid-insoluble coA, and ATP content were measured after incubation with and without MO. Our results reveal that MO is a mitochondrial uncoupler. State 4 respiration was increased while the respiratory control ratio was decreased. The intramitochondrial content of ATP was also decreased. There were substantial changes in the reduction of the respiratory chain components after incubation of mitochondria with MO. This decelerative effect on mitochondrial electron transport was alleviated by the addition of coenzyme Q and/or carnitine. These effects of MO on mitochondrial respiration may be due to changes in fatty acid metabolism caused by MO as MO caused a shift in the proportion of acid-soluble or acid-insoluble coA esters. Supplementary therapy with L-carnitine and coenzyme Q may be useful in the management of MO-induced Reye's syndrome.