Expression cloning of beta 1,4 N-acetylgalactosaminyltransferase cDNAs that determine the expression of GM2 and GD2 gangliosides.
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Biomedical subjects
Publications and source records attributed to Y Nagata.
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Free D-serine distribution in vertebrate brains was investigated. In various brain regions of the lower vertebrate species, carp, frog and chick, free D-serine levels were low. On the contrary, in the mammals, mouse, rat and bull, the contents of free D-serine were high in the forebrain (around 400 nmol/g wet weight, and the ratio of D-serine to L-serine, was D/L = 0.4), and low in the hindbrain. In developing mice, D-serine levels in the cerebrum increased with age and attained the adult level (D/L = 0.40) 8 weeks after birth. In the cerebellum and brain stem, the free D-serine levels increased with age until 2 weeks, followed by a decrease to the adult levels: the D/L ratios remained constant until 2 weeks of age, then decreased to 0.03 in the cerebellum and 0.12 in the brain stem. Free D-serine was shown not to be of microbial origin using germ-free mice. In the rat forebrain, D-serine was evenly distributed in two cerebral regions, namely frontal and occipital lobes. The D/L ratios in other regions of forebrain, hippocampus and hypothalamus, were comparable to the cerebrum (D/L = 0.4), while that in the olfactory bulb was lower (D/L = 0.12). In the rat cerebrum, the D-serine content in the grey matter was significantly higher than that in the white matter. The contents of free D-serine in bovine cerebrum and cerebellum were similar to those in other mammalian brains, but the D/L ratio for bovine cerebral grey matter was lower than that for the cerebral white matter.(ABSTRACT TRUNCATED AT 250 WORDS)
In order to map the gene that is responsible for the DNA-repair defect in severe combined immune deficient (SCID) mice, a mixture of microcells independently isolated from mouse A9 cells containing pSV2neo-tagged human chromosomes 5, 7, 8, 9, 11, 15, 18 or 20 were fused with SCID fibroblast cell lines SCVA2 and SCVA4, which were originally established from lung tissue of the C.B.17-scid/scid mouse by SV40 virus transfection. After irradiation with 60Co gamma-rays and selection with antibiotic G418, 12 independent clones were obtained, of which 4 contained an intact chromosome 8, 3 clones contained a deleted chromosome 8 [del(8)q22-->qter or del(8)q23--> qter] and remaining 5 had no detectable or specific human chromosome. We further independently transferred a single human chromosome 8 or 11 into the SCVA cells via microcell fusion, and examined the radiation sensitivity of the microcell hybrids. Complementation of the radiation sensitivity was correlated with the presence of human chromosome 8 in microcell hybrids, whereas no correlation was observed in clones following the transfer of human chromosome 11. Thus, the results indicate that human chromosome 8 restored high sensitivity to ionizing radiation. A number of subclones that were radiation resistant or sensitive were isolated from the microcell hybrids. The concordance of the radiation sensitivity with the presence or absence of specific DNA fragments on chromosome 8 indicates that the human gene is located on the centromeric region of chromosome 8, i.e., 8p11.1--> q11.1.
Liver injury by endotoxin given during regeneration following a 70% hepatectomy was examined in Wistar rats. The intravenous administration of endotoxin caused an elevation of the serum GPT level, and severe damage of the remnant liver showing centrilobular necrosis with microthrombi. The highest mortality was induced by the administration of endotoxin to rats 24 h after hepatectomy. Kupffer cells in the regenerative phase of the liver showed an augmented in vitro production of both tumor necrosis factor (TNF) and interleukin-1 (IL-1). The simultaneous administration of heparin and prostagladin E1 (PGE1), which is known to suppress the production of TNF and IL-1, reduced the magnitude of liver injury and the mortality of these rats. The absence of any direct cytotoxic effect of TNF and IL-1 against liver cells suggested that the cytokines, produced by Kupffer cells, play an important but indirect role in the remnant liver injury induced by endotoxin after hepatectomy.
The hypocholesterolemic and antioxidant activities of probucol (PB) were examined in rats which were fed for 10 days with diets supplemented with or without 0.02% polychlorinated biphenyls (PCB). Dietary intake of PCB caused multiple effects on lipid metabolism, such as increased levels of both serum and HDL cholesterol, and increased TBA-reactive substances (TBARS), in hepatic subcellular fractions. PB 1% in comparison with either control or alpha-tocopherol (Toc) 0.1%, reduced the serum cholesterol levels in normolipemic as well as in PCB-induced hypercholesterolemic rats. In addition, this drug ameliorated the elevated TBARS induced by PCB in the hepatic subcellular fractions, although less antioxidant activity was noted in rats fed PB than in those fed Toc. The microsomes isolated from various groups were incubated for 2h at 37 degrees C in the presence or the absence of ferrous iron in vitro; microsomes from the PB-fed rats were as much resistant against lipid peroxidation in ferrous-free incubation medium as were those from Toc-fed rats, while in the presence of ferrous iron there was a higher antioxidant effect on lipid peroxidation in the latter fraction than in the former. HPLC analyses showed that less PB than Toc was incorporated into the hepatic subcellular fractions, suggesting that the concentration of antioxidants in hepatic subcellular fractions determine the extent of lipid peroxidation in situ. These results suggest that the administration of PB is an effective approach for the treatment of both hypercholesterolemia and elevated lipid peroxidation while Toc ameliorates only an elevated lipid peroxidation.
D-Alanine was administered orally to mutant mice lacking D-amino acid oxidase (EC 1.4.3.3). The mice had free access to drinking water containing 0.5% D- or L-alanine or 0.1% D-alanine for 2 weeks. The mice were then killed, and levels of the D- and L-enantiomers of free alanine, serine, proline, glutamate, and aspartate were determined in serum, liver, kidney, cerebrum, and cerebellum tissues. D-Alanine content increased by 60-fold (liver) to 110-fold (serum, brain), although the L-alanine level did not change. The increase of serum and brain D-alanine concentrations in animals fed 0.5% D-alanine was approximately five times more than that in animals fed 0.1% D-alanine, ie, the increase was roughly D-alanine dose-dependent in these tissues. The increase due to 0.5% D-alanine administration was reduced by 50% 17 hours after administration of D-alanine was stopped. Administration-induced increases in D-alanine levels in the cerebrum and cerebellum were not less than those in the serum, suggesting that D-alanine passed the blood-brain barrier quite freely. In the liver but not in other tissues, there were slight increases in D-serine and D-proline levels after administration of D-alanine. Administration of D-alanine produced no alterations in free glutamate and aspartate levels. No D-enantiomers of alanine, serine, proline, glutamate, or aspartate were detected in the liver and kidney tissue proteins of any animals, even in the mutant mice that received 0.5% D-alanine.
A rare case of chronic subdural hematoma associated with a middle meningeal arteriovenous fistula was treated by a combination of embolization and burr hole drainage. This clinical situation might be missed in this era of computed tomography, when cerebral angiography is seldom indicated for the diagnosis of neuro-traumatic diseases. We should bear in mind the possibility of this clinical situation of a chronic subdural hematoma associated with a linear skull fracture crossing the middle meningeal groove in order to avoid possible hemorrhagic complications during surgery for chronic subdural hematoma.
A CT simulator (CT-S) is a real-time, CT-linked, 3-D treatment planning system, which consists of a CT scanner, a multi-image display, a treatment planning device with real-time visual optimization, and a laser beam projector. This system was clinically evaluated in 339 Stage 0, I and II breast cancers in 337 patients who received breast conserving therapy. Following quadrantectomy or wide excision with complete axillary dissection, a total of 50 Gy was delivered to the ipsilateral breast using 60Co gamma-rays. In patients with involved surgical margins, boost electron irradiation was also given. Treatment planning could be accomplished within 40-50 min using the CT-S. The parameters for the tangential portals could be optimized for each patient, and the wedge filters and the electron energy for boost irradiation could be appropriately selected. The incidence of moist desquamation and depigmentation at the areola was slightly decreased with the use of wedge filters. During the follow-up for 2-71 months (median, 22 months), local recurrence and symptomatic radiation pneumonitis occurred in one patient each. The CT-S appears to be useful for the individualized optimization of tangential irradiation fields in breast conserving therapy.
Cyclic GMP (cGMP) production in superior cervical sympathetic ganglia (SCG) isolated from rats was markedly enhanced (approx. 4.5-fold) by the addition of L-arginine (L-Arg, 100 microM) plus an inhibitor (3-isobutyl-1-methylxanthine) for cGMP hydrolytic enzyme during in vitro aerobic incubation at 37 degrees C for 10 min. This accelerated accumulation of ganglionic cGMP was effectively reversed by approximately 50% when NG-monomethyl-L-arginine (L-NMMA, 50 microM), a compound that inhibits nitric oxide (NO) synthesis from L-Arg, was further added to the medium. These observations imply that cGMP production with possible involvement of a mechanism depending on NO synthesis may be functionally operating in the ganglionic tissue. Application of norepinephrine (NE, 50 microM) with pargyline, a monoamine oxidase inhibitor, to the medium also elevated the ganglionic cGMP level at a magnitude comparable to that shown by L-Arg addition, while co-addition of L-NMMA largely (approx. -60%) eliminated the NE-induced increase in ganglionic cGMP formation. In axotomized SCG one week prior to examination, where sympathetic neurons were degenerated and reactive proliferation of glial cells was in progress, augmented stimulatory effect (more than 8-fold) of NE on cGMP production was seen compared to that caused in unoperated ganglia or in SCG 1 week following denervation, where preganglionic cholinergic nerve terminals were destroyed. When axotomized SCG were transferred to in vitro incubation conditions, addition of an alpha-1 adrenergic antagonist, prazosin (1 microM) to the medium virtually reduced the accelerative effect of NE to less than 25% of the NE-induced cGMP level in the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)
The activity of transglutaminase (TG), a Ca(2+)-dependent enzyme indicating tissue degradation or differentiation, showed in isolated adult rat superior cervical ganglia (SCG) a rapid (within 15 to 30 min) and marked (approx. 5- to 8-fold) increase with the addition of either GM1 ganglioside (GM1, 5 nM), which is rich in synapses, or sialyl cholesterol (SC, 20 microM), a synthetic sialic acid-containing compound, to the incubation medium at 37 degrees C. Under the same incubation conditions, addition of GM1 or SC decreased protein kinase C (PKC) activity (-26% to -39%) in the cytosolic fraction of the SCG, but increased the enzymic activity (+39% to +61%) in the particulate (cell membrane) fraction, suggesting that a sialic acid-containing compound (GM1 or SC) promotes PKC translocation from the cytosol to the membrane in ganglionic neurons. By contrast, addition of a promoting factor for survival of sympathetic neurons even in adulthood, nerve growth factor, (NGF, 0.25 micrograms/ml) to the medium significantly decreased ganglionic TG activity (-43%). This inhibition was completely antagonized by the co-addition of NGF-monoclonal antibody (0.75 microgram/ml). An effective blockade of GM1- or SC-induced stimulation of ganglionic TG activity was seen by further addition of NGF to the medium. Also, NGF almost abolished the translocation of ganglionic PKC activity induced by the sialic acid-containing compounds, although either NGF or 12-O-tetradecanoylphorbol ester (TPA) alone stimulated the cytosolic PKC activity (approx. +30%) in the tissue.(ABSTRACT TRUNCATED AT 250 WORDS)
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In Pseudomonas paucimobilis UT26, gamma-hexachlorocyclohexane (gamma-HCH) is converted to 2,5-dichloro-2,5-cyclohexadiene-1,4-diol (2,5-DDOL), which is then metabolized to 2,5-dichlorohydroquinone. Here, we isolated from the genomic library of UT26 two genes which expressed 2,5-DDOL dehydrogenase activity when they were transformed into P. putida and Escherichia coli. Both gene products had an apparent molecular size of 28 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The first gene, named linC, located separately from the two genes (linA and linB) which we had already cloned as genes involved in the gamma-HCH degradation. The other, named linX, located about 1 kb upstream of the linA gene encoding gamma-HCH dehydrochlorinase. A gamma-HCH degradation-negative mutant, named UT72, which lacked the whole linC gene but had the intact linX gene was isolated. The linC gene given in a plasmid could complement UT72. These results strongly suggest that the linC gene but not the linX gene is essential for the assimilation of gamma-HCH in UT26. Deduced amino acid sequences of LinC and LinX show homology to those of members of the short-chain alcohol dehydrogenase family.
Pseudomonas sp. strain KKS102 is able to degrade biphenyl and polychlorinated biphenyls via the meta-cleavage pathway. We sequenced the upstream region of the bphA1A2A3BCD (open reading frame 1 [ORF1]) A4 and found four ORFs in this region. As the deduced amino acid sequences of the first, second, and third ORFs are homologous to the meta-cleavage enzymes from Pseudomonas sp. strain CF600 (V. Shingler, J. Powlowski, and U. Marklund, J. Bacteriol. 174:711-724, 1992), these ORFs have been named bphE, bphG, and bphF, respectively. The fourth ORF (ORF4) showed homology with ORF3 from Pseudomonas pseudoalcaligenes KF707 (K. Taira, J. Hirose, S. Hayashida, and K. Furukawa, J. Biol. Chem. 267:4844-4853, 1992), whose function is unknown. The functions of meta-cleavage enzymes (BphE, BphG, and BphF) were analyzed by using crude extracts of Escherichia coli which expressed the encoding genes. The results showed that bphE, bphG, and bphF encode 2-hydroxypenta-2,4-dienoate hydratase, acetaldehyde dehydrogenase (acylating), and 4-hydroxy-2-oxovalerate aldolase, respectively. The biphenyl and polychlorinated biphenyl degradation pathway of KKS102 is encoded by 12 genes in the order bphEGF (ORF4)A1A2A3BCD (ORF1)A4. The functions of ORF1 and ORF4 are unknown. The features of this bph gene cluster are discussed.
The nucleotide sequence of the downstream region of the bph operon from Pseudomonas sp. strain KKS102 was determined. Two open reading frames (ORF1 and ORF2) were found in this region, and the deduced amino acid sequence of ORF2 showed homology with the sequences of four ferredoxin reductases of dioxygenase systems. When this region was inserted just upstream of the bph operon, which does not contain a gene encoding ferredoxin reductase, biphenyl dioxygenase activity was detected. The 24- and 44-kDa polypeptides predicted from the two open reading frames were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Crude extract which contained the products of ORF2 and bphA1A2A3 showed cytochrome c reduction activity. These data clearly suggest that ORF2 encodes ferredoxin reductase. The deduced amino acid sequence of ORF1 does not show significant homology with the sequences of any other proteins in the SWISS-PROT data bank, and the function of ORF1 is unknown.
Among mushrooms of Pleurotus cornucopiae two kinds of fruit bodies, lectin (PCL)-containing and -deficient, were found. The PCL-deficient fruit body was found to contain a 16.5-kDa protein, which was purified to homogeneity and crystallized. Properties of the protein were investigated in comparison with PCL. The protein consisted of four identical subunits each having a molecular mass of 16.5 kDa, which was close to that of PCL. Partial amino acid sequences of the two proteins were analyzed and some sequence homology was found, although the protein did not cross-react with anti-PCL serum and it was devoid of binding activity for mucin, an inhibitor of PCL. The 16.5-kDa protein was not found in vegetatively growing mycelia, indicating that the synthesis of the protein was developmentally regulated as was PCL. The results suggest that the 16.5-kDa protein was related to PCL.
The complete amino acid sequence of a lectin-related 16.5-kDa protein (PCL-RP) isolated from fruit bodies of a lectin-deficient strain of P. cornucopiae is presented. The sequences of six out of the seven peptides generated by digestion with lysylendopeptidase and four of the five peptides generated by cyanogen bromide cleavage were completely analyzed. Overlapping peptides were obtained by arginylendopeptidase digestion. PCL-RP was a single-chain protein consisting of 144 amino acid residues and its N-terminal serine was blocked with acetate. A proline-rich sequence was found in the carboxyl terminal portion. The N-terminal sequence of PCL-RP showed some homology with those of two known Basidiomycete lectins.
Five patients with kissing aneurysms (adherent internal carotid-posterior communicating artery and ipsilateral internal carotid-anterior choroidal artery aneurysms) are reported. There was female predominance and the subarachnoid hemorrhage was commonly due to rupture of the proximal posterior communicating artery aneurysm. Despite the demonstration of angiographic cleavage, the two aneurysms adhere to each other, which makes surgical dissection difficult. Meticulous dissection of the aneurysmal necks and preservation of the blood flow in the anterior choroidal artery are of vital importance.
We report the clinical course of cytomegalovirus (CMV) retinitis associated with acquired immunodeficiency syndrome (AIDS) from the initial onset. The patient was a 40-year-old human immunodeficiency virus antibody-positive male with hemophilia A. He was diagnosed as having AIDS on the basis of pneumocystis carinii pneumonia. Ophthalmoscopic examination disclosed a small white punctate lesion at the macular area in his right eye. Because the lesion enlarged gradually with hemorrhages, it was suspected to be CMV retinitis. However, further examination was impossible due to his severe general condition. He died five months later and the autopsy disclosed disseminated CMV infection. Ocular histopathological examination revealed CMV retinitis. The earliest sign of CMV retinitis is supposed to be a white punctate retinal lesion, which becomes a small white patchy lesion resembling a cotton-wool spot. It may gradually progress to diffuse retinal involvement, frequently associated with hemorrhages.