Optic nerve and spinal cord manifestations of malignant atrophic papulosis (Degos disease)

A fatal case of malignant atrophic papulosis (Degos disease) with optic nerve and spinal cord involvement is described. Magnetic resonance imaging (MRI) of the optic nerve showed abnormal signal enhancement on fat suppressed T1 weighted images after intravenous meglumine gadopentetate infusion. On T2 weighted sagittal images, a sawtooth pattern was observed over seven vertebral segments of the spinal cord. On necropsy, a severe loss of myelinated nerve fibres in the left optic nerve was seen, with thrombotic obstruction of the central retinal artery. Spongy degeneration was observed in all levels of the spinal cord, with patchy and motheaten patterns caused by thromboses and endothelial proliferation in subarachnoid vessels. Findings on MRI were consistent with findings on pathological examination.

Characterization of the metal-substituted dipeptidyl peptidase III (rat liver)

Dipeptidyl peptidase III (DPP III) (EC 3.4.14.4), which has a HELLGH-E (residues 450-455, 508) motif as the zinc binding site, is classified as a zinc metallopeptidase. The zinc dissociation constants of the wild type, Leu(453)-deleted, and E508D mutant of DPP III at pH 7.4 were 4.5 (+/-0.7) x 10(-13), 5.8 (+/-0.7) x 10(-12), and 3.2 (+/-0.9) x 10(-10) M, respectively. The recoveries of the enzyme activities by the addition of various metal ions to apo-DPP III were also measured, and Co(2+), Ni(2+), and Cu(2+) ions completely recovered the enzyme activities as did Zn(2+). The dissociation constants of Co(2+), Ni(2+), and Cu(2+) ions for apo-DPP III at pH 7.4 were 8.2 (+/-0.9) x 10(-13), 2.7 (+/-0.3) x 10(-12), and 1.1 (+/-0.1) x 10(-14) M, respectively. The shape of the absorption spectrum of Co(2+)-DPP III was very similar to that of Co(2+)-carboxypeptidase A or Co(2+)-thermolysin, in which the Co(2+) is bound to two histidyl nitrogens, a water molecule, and a glutamate residue. The absorption spectrum of Cu(2+)-DPP III is also very similar to that of Cu(2+)-thermolysin. The EPR spectrum and the EPR parameters of Cu(2+)-DPP III were very similar to those of Cu(2+)-thermolysin but slightly different from those of Cu(2+)-carboxypeptidase A. The five lines of the superfine structure in the perpendicular region of the EPR spectrum in Cu(2+)-DPP III suggest that nitrogen atoms should coordinate to the cupric ion in Cu(2+)-DPP III. All of these data suggest that the donor set and the coordination geometry of the metal ions in DPP III, which has the HExxxH motif as the metal binding site, are very similar to those of the metal ions in thermolysin, which has the HExxH motif.

ATP-binding cassette transporter-1 induces rearrangement of actin cytoskeletons possibly through Cdc42/N-WASP

Positional cloning approaches revealed that Tangier disease (TD), a genetic high density lipoprotein deficiency, is associated with mutations in the ATP-binding cassette transporter-1 (ABCA1) gene. However, the biological function of ABCA1 is still not fully investigated. Recently, we have reported that the cells from the patients with TD had abnormal actin cytoskeletons in association with decreased expression of Cdc42, a member of RhoGTPases family. In the present study, we have found that actin cytoskeletons were altered in HEK293 cells transfected with human ABCA1 (hABCA1) cDNA. Cells expressing hABCA1 were divided into the following two groups by the distinct morphology with altered actin cytoskeletons: one had increased formation of filopodia (designated as Type I) and the other had long protrusions (designated as Type II). Type I cells had morphology similar to that of cells transfected with dominant active form of Cdc42 (Cdc42-DA, V12Cdc42Hs-DA). Type II cells had morphology similar to that of cells transfected with neural Wiskott-Aldrich Syndrome Protein (N-WASP),one of the established downstream effector molecules of Cdc42. We have obtained the data showing a possible pathway of ABCA1/Cdc42/N-WASP by the following experiments. Introduction of mutant of Cdc42 (dominant negative form of Cdc42, N17Cdc42Hs-DN) and N-WASP (N-WASP lacking verprolin homology domain, N-WASPDeltaVPH), both of which are supposed to have potential to inhibit rearrangement of actin cytoskeletons, significantly inhibited the morphological changes induced by expression of hABCA1. Immunoprecipitation study with FLAG-tagged ABCA1 (hABCA1-FLAG) revealed that Cdc42 was coimmunoprecipitated with hABCA1-FLAG. In addition, we have demonstrated possible intracellular colocalization of these two molecules in the overexpressing cells by the confocal laser microscopy. These results may suggest that hABCA1 regulates actin organization through the possible interaction with Cdc42Hs.

Decreased expression of a member of the Rho GTPase family, Cdc42Hs, in cells from Tangier disease - the small G protein may play a role in cholesterol efflux

Cholesterol efflux (CE) is the initial and important step of reverse cholesterol transport (RCT), a major protective system against atherosclerosis. However, most of the molecular mechanism for CE still remains to be clarified. In the present study, cDNA subtraction revealed that the expression of a member of the Rho GTPase family, Cdc42Hs, was markedly decreased in both passaged fibroblasts and macrophages (Mφ) from patients with Tangier disease (TD), a rare lipoprotein disorder with reduced CE. This small G protein is known to have many cell biological activities such as rearrangement of actin cytoskeleton and vesicular transport, however the association between this molecule and lipid transport has never been reported. We demonstrate that MDCK cells expressing the dominant negative form of Cdc42Hs had reduced CE, inversely ones expressing the dominant active form had increased CE. From these observations, we would like to raise a novel hypothesis that this type of small G protein may play a role in some steps of CE. To our knowledge, the present study is the first demonstration that the expression of this molecule is altered in cells from human disease.

Human alpha-N-acetylgalactosaminidase: site occupancy and structure of N-linked oligosaccharides

Human alpha-N-acetylgalactosaminidase (alpha-GalNAc; also known as alpha-galactosidase B) is the lysosomal exoglycohydrolase that cleaves alpha-N-acetylgalactosaminyl moieties in glycoconjugates. Mutagenesis studies indicated that the first five (N124, N177, N201, N359, and N385) of the six potential N-glycosylation sites were occupied. Site 3 occupancy was important for enzyme function and stability. Characterization of the N-linked oligosaccharide structures on the secreted enzyme overexpressed in Chinese hamster ovary cells revealed highly heterogeneous structures consisting of complex (approximately 53%), hybrid (approximately 12%), and high mannose-type (approximately 33%) oligosaccharides. The complex structures were mono-, bi-, 2,4-tri-, 2,6-tri-, and tetraantennary, among which the biantennary structures were most predominant (approximately 53%). Approximately 80% of the complex oligo-saccharides had a core-region fucose and 50% of the complex oligosaccharides were sialylated exclusively with alpha-2,3-linked sialic acid residues. The majority of hybrid type oligo-saccharides were GalGlcNAcMan(6)GlcNAc-Fuc(0-1)GlcNAc. Approximately 54% of the hybrid oligosaccharide were phosphorylated and one-third of these structures were further sialylated, the latter representing unique phosphorylated and sialylated structures. Of the high mannose oligosaccharides, Man(5-7)GlcNAc(2) were the predominant species (approximately 90%) and about 50% of the high mannose oligosaccharides were phosphorylated, exclusively as monoesters whose positions were determined. Comparison of the oligosaccharide structures of alpha-GalNAc and alpha-galactosidase A, an evolutionary-related and highly homologous exoglycosidase, indicated that alpha-GalNAc had more completed complex chains, presumably due to differences in enzyme structure/domains, rate of biosynthesis, and/or aggregation of the overexpressed recombinant enzymes.

Expression of human scavenger receptor class B type I in cultured human monocyte-derived macrophages and atherosclerotic lesions

The scavenger receptor class B type I (SR-BI) and its human homologue CLA-1 (CD36 and LIMPII Analogous-1) have recently been identified to bind HDL and mediate the selective uptake of HDL lipids. Tissue distribution of both murine and human receptors is quite similar, in that they are expressed abundantly in liver and steroidogenic tissues. However, expression and function of the human SR-BI (hSR-BI), in the periphery of reverse cholesterol transport such as macrophages, are still unclear. In the present study, we have raised two different kinds of anti-hSR-BI polypeptide antibodies (Abs): one against the extracellular domain and the other against the intracellular domain. We have investigated the expression of hSR-BI mRNA and immunoreactive mass in freshly isolated cultured human monocyte-derived macrophages (hMphi) and in atherosclerotic lesions. Contrary to the earlier report, hSR-BI mRNA was expressed in cultured hMphi and markedly upregulated with differentiation, determined by Northern blot and reverse transcriptase-based polymerase chain reaction analyses. The mRNA expression pattern during differentiation of hMphi was very similar to those of SR class A and another member of SR class B, CD36. Protein expression was confirmed by Western blot analyses with the above Abs to show a major 83-kDa band. Modified lipoproteins such as oxidized LDL and acetylated LDL induced a 5-fold increase in mRNA and protein expression of hSR-BI. Confocal immunofluorescence microscopy demonstrated that hSR-BI immunoreactive mass was detectable as a heterogeneous, punctate staining pattern. Furthermore, immunohistochemical analysis showed that immunoreactive mass of hSR-BI was detected in foam cells in human aortic atherosclerotic lesions and that there was no significant difference of staining patterns between the two Abs. This study clearly demonstrates that hSR-BI is expressed in the lipid-laden macrophages in human atherosclerotic lesions, suggesting that it is very important to know its function and regulation in hMphi to understand the biological utility of this molecule.

Biosynthesis of 1,2-dieicosapentaenoyl-sn-glycero-3-phosphocholine in Caenorhabditis elegans

Previously, we showed that lowering the growth temperature increased the level of eicosapentaenoic acid (EPA) in the phosphatidylcholine (PtdCho) of Caenorhabditis elegans. In this study, we investigated the molecular species composition of PtdCho of C. elegans, with an emphasis on EPA-containing species. C. elegans contained a substantial amount of 1,2-dipolyunsaturated fatty acid-containing PtdCho (1,2-diPUFA-PtdCho) species, such as arachidonic acid/EPA and EPA/EPA, which are unusual phospholipids in higher animals. The EPA/EPA-PtdCho content was significantly increased in C. elegans grown at a low temperature. To examine the possibility that the acyltransferase activity involved in the remodeling of phospholipids accounts for the production of 1,2-diPUFA-PtdCho, we investigated the substrate specificity of this enzyme in C. elegans and found that it did not exhibit a preference for saturated fatty acid for acylation to the sn-1 position of PtdCho. The efficacy of the esterification of EPA to the sn-1 position was almost equal to that of stearic acid. The lack of preference for a saturated fatty acid for acylation to the sn-1 position of PtdCho is thought to result in the existence of the unusual 1,2-diEPA-PtdCho in C. elegans.

Activation of monocytes in vivo causes intracellular accumulation of lipoprotein-derived lipids and marked hypocholesterolemia--a possible pathogenesis of necrobiotic xanthogranuloma

Necrobiotic xanthogranuloma (NXG) is a rare histiocytic disease with generalized xanthomatosis. However, most cases with NXG are normolipidemic or hypolipidemic. The mechanism for the formation of xanthoma in NXG has not yet been clarified. We observed a case of NXG with severe hypocholesterolemia (total cholesterol: 1.69 mmol/l) and analyzed the function of monocytes in this case. Histological examinations by light microscopy revealed a large amount of lipid deposition in the patient's freshly isolated monocytes. The patient's monocytes showed a 3-fold increase in cholesteryl ester content and a 3-fold enhancement of acetyl low density lipoprotein (LDL) uptake compared with the control monocytes. However, no significant difference was noted in the expression of CD36 protein and the mRNA levels of scavenger receptor-class A (SR-A) between the monocytes of the patient and the control. The phagocytotic ability of the patient's monocytes was enhanced 1.5-fold compared with that of the control monocytes. These findings suggest that the activated monocytes may have degraded the modified LDL via a pathway other than CD36 or SR-A, and accumulated a great amount of lipids in vivo. In conclusion, the present study has demonstrated a possible pathogenesis of NXG that the activation of monocytes in vivo may contribute to the intracellular accumulation of lipoprotein-derived lipids leading to non-inherited xanthomatosis and the marked hypocholesterolemia.

Effect of visceral fat accumulation on uric acid metabolism in male obese subjects: visceral fat obesity is linked more closely to overproduction of uric acid than subcutaneous fat obesity

We investigated the relationship between uric acid (UA) metabolism and fat distribution in 36 obese men with a mean +/- SD age of 38 +/- 16 years and mean body-mass index (BMI) of 34 +/- 4 kg/m2. Subjects were divided into two groups: subcutaneous fat obesity (SFO) and visceral fat obesity (VFO), according to their abdominal fat distribution based on the results of computed tomography (CT). SFO was defined as having a ratio of visceral fat area (VFA) to subcutaneous fat area (V/S) of less than 0.4, and VFO was defined as having a V/S ratio > or = 0.4. The levels of serum total cholesterol (T-Chol), triglyceride (TG), and fasting plasma glucose (FPG), and the diastolic blood pressure (dBP) were significantly higher in the VFO group than in the SFO group. Serum UA levels were much higher in both the SFO and VFO groups than in the non-obese control group (492 +/- 107 and 474 +/- 90 v 309 +/- 48 micromol/L, respectively). The 24-hour urinary urate excretion (u-UA24h) and the UA clearance (Cua) to creatinine clearance (Ccr) ratio were significantly higher in the VFO group than in the SFO group (3.75 +/- 1.43 v 2.69 +/- 1.12 mmol/d, P < .05; and 5.9% +/- 2.0% v 3.6% +/- 1.7%, P < .001, respectively). The frequency of hyperuricemia was markedly higher in both the SFO and VFO groups compared with the control group (71% and 73% v 0%, respectively). Although the high serum UA level seemed to be related to low u-UA24h in 80% of SFO subjects with hyperuricemia, this was the case in only 10% of VFO subjects. While 44% of VFO subjects with hyperuricemia were designated as an overproduction type. These results suggest that the mechanism of hyperuricemia in obesity may be affected by the difference in body fat distribution and that the assessment of body fat distribution and types of hyperuricemia is crucial for the treatment of obese patients with hyperuricemia.

Human alpha-galactosidase A: characterization of the N-linked oligosaccharides on the intracellular and secreted glycoforms overexpressed by Chinese hamster ovary cells

Human alpha-galactosidase A (alpha-Gal A) is the lysosomal glycohydrolase that cleaves the terminal alpha-galactosyl moieties of various glycoconjugates. Overexpression of the enzyme in Chinese hamster ovary (CHO) cells results in high intracellular enzyme accumulation and the selective secretion of active enzyme. Structural analysis of the N -linked oligosaccharides of the intracellular and secreted glycoforms revealed that the secreted enzyme's oligosaccharides were remarkably heterogeneous, having high mannose (63%), complex (30%), and hybrid (5%) structures. The major high mannose oligosaccharides were Man5-7GlcNAc2 species. Approximately 40% of the high mannose and 30% of the hybrid oligosaccharides had phosphate monoester groups. The complex oligosaccharides were mono-, bi-, 2,4-tri-, 2,6-tri- and tetraantennary with or without core-region fucose, many of which had incomplete outer chains. Approximately 30% of the complex oligosaccharides were mono- or disialylated. Sialic acids were mostly N -acetylneuraminic acid and occurred exclusively in alpha2, 3-linkage. In contrast, the intracellular enzyme had only small amounts of complex chains (7.7%) and had predominantly high mannose oligosaccharides (92%), mostly Man5GlcNAc2 and smaller species, of which only 3% were phosphorylated. The complex oligosaccharides were fucosylated and had the same antennary structures as the secreted enzyme. Although most had mature outer chains, none were sialylated. Thus, the overexpression of human alpha-Gal A in CHO cells resulted in different oligosaccharide structures on the secreted and intracellular glycoforms, the highly heterogeneous secreted forms presumably due to the high level expression and impaired glycosylation in the trans- Golgi network, and the predominately Man5-7GlcNAc2 cellular glycoforms resulting from carbohydrate trimming in the lysosome.

Acetylcholine-induced coronary microvascular vasospasm in a patient with angina pectoris and normal coronary angiogram--a case report

We demonstrated a continuous intracoronary infusion of acetylcholine-induced marked decrease of coronary blood flow estimated by intracoronary Doppler flow wire without significant epicardial coronary narrowing. This case can be called a patient with microvascular vasospastic angina.

Biochemical and morphological expression of early prenatal caprine beta-mannosidosis

Lysosomal storage diseases associated with early-onset pathological changes may require prenatal therapy to avert the profound effects of the metabolic error on organs, especially the central nervous system. The present investigation determined the extent of expression of beta-mannosidase deficiency in the caprine fetus at 62 days of gestation, near the end of the period of immunotolerance when donor cells can engraft in various organs without immune rejection and supply missing enzyme. Three pairs of obligate carrier goats from the beta-mannosidosis colony were mated. Out of six fetuses delivered at 62 days of gestation, one (V385) was identified by measurement of beta-mannosidase activity as the only fetus affected with beta-mannosidosis. Thin-layer chromatography and quantitation of oligosaccharides revealed the presence of tri- and disaccharides, typical of beta-mannosidosis, only in V385. Morphological analysis revealed cytoplasmic vacuolation typical of beta-mannosidosis in V385; in thyroid, spinal cord, and kidney, the pattern of vacuolation was similar to, but less severe than, that observed previously in newborn affected goats. On the basis of these results, it will be possible to determine the effects of prenatal cell transplantation therapeutic strategies performed during the period of immunotolerance by monitoring phenotypic characteristics after treatment.

Novel beta-D-galactofuranose-containing high-mannose type oligosaccharides in ascorbate oxidase from Acremonium sp. HI-25

Ascorbate oxidase from the fungus Acremonium sp. HI-25 is a copper-containing glycoprotein that catalyzes the oxidation of ascorbic acid to dehydroascorbic acid. Monosaccharide composition analysis showed that the enzyme contains exclusively N-linked oligosaccharide chains. Following liberation by hydrazinolysis/re-N-acetylation, and fractionation by HPLC on anion exchange. Amide-80 and/or octadecyl silica columns after derivatization with p-aminobenzoic ethyl ester, the structures of the twelve major neutral oligosaccharides were identified by FAB-MS, 400 MHz 1H-NMR, methylation analysis, mild acid hydrolysis, and/or sequential exoglycosidase digestions. Acremonium sp. ascorbate oxidase was found to consist of high-mannose type oligosaccharides (76.3%) having 4 to 9 mannose residues and a series of novel D-galactofuranose-containing high-mannose type oligosaccharides (18.6%) with the following structure.

Phospholipids from the free-living nematode Caenorhabditis elegans

The phospholipid and the fatty chain compositions of diacyl, alkylacyl and alkenylacyl glycerophospholipids of the free-living nematode, Caenorhabditis elegans, were investigated. The phospholipids were comprised of 54.5% ethanolamine glycerophospholipid (EGP), 32.3% choline glycerophospholipid (CGP), 8.1% sphingomyelin and 5.1% others. The most abundant fatty acid in CGP was eicosapentaenoic acid (20:5n-3). The fatty acids in CGP were more unsaturated than those in EGP. Alkenylacyl and alkylacyl subclasses accounted for 1.0 and 2.6%, respectively, of CGP and 14.0 and 19.6%, respectively, of EGP. At least 80% of the alkenyl and alkyl groups were 18:0 chains and the remaining were odd numbered chains. The potential presence of platelet-activating factor (PAF) was examined by bioassay, but PAF-like activity was not detected in the extracts of this nematode.

Structures of asparagine linked oligosaccharides of immunoglobulins (IgY) isolated from egg-yolk of Japanese quail

Structures of the Asn linked oligosaccharides of quail egg-yolk immunoglobulin (IgY) were determined in this study. Asn linked oligosaccharides were cleaved from IgY by hydrazinolysis and labelled with p-aminobenzoic acid ethyl ester (ABEE) after N-acetylation. The ABEE labelled oligosaccharides were then fractionated by a combination of Concanavalin A-agarose column chromatography and anion exchange, normal phase and reversed phase HPLC before their structures were determined by sequential exoglycosidase digestion, methylation analysis, HPLC, and 500 MHz 1H-NMR spectroscopy. Quail IgY contained only neutral oligosaccharides of the following categories: the glucosylated oligomannose type (0.6% Glc alpha 1-3Glc alpha 1-3Man9GlcNAc2; 35.6%, Glc alpha 1-3Man7-9GlcNAc2). oligomannose type (15.0%, with the structure Man5-9GlcNAc2) and biantennary complex type with core structures of -Man alpha 1-3(-Man alpha 1-6)Man beta 1-4GlcNAc beta 1-4GlcNAc (9.9%), -Man alpha 1-3 (GlcNAc beta 1-4)(-Man alpha 1-6)Man beta 1-4GlcNAc beta 1-4GlcNAc (25.1%) and -Man alpha 1-3(GlcNAc beta 1-4)(-Man alpha 1-6)Man beta 1-4GlcNAc beta 1-4(Fuc alpha 1-6)GlcNAc (11.4%). Although never found in mammalian proteins, glucosylated oligosaccharides (Glc1Man7-9GlcNAc2) have been located previously in hen IgY.

Possible beta-mannosidosis chimera. Altered expression of metabolic perturbations

An aberrant beta-mannosidosis phenotype in a 5-month-old triplet goat kid was characterized by a late postnatal onset of mild neurological symptoms. Necropsy examination revealed relatively normal myelination; however, the distribution of cytoplasmic vacuolation in the kidney and brain was similar to that observed in neonatal beta-mannosidosis. Variable engraftment of donor stem cells, resulting from transplacental transfusion of stem cells from a normal sibling during the immunotolerant period, may have modified the expected severe beta-mannosidosis phenotype. This investigation was designed to determine the effects of a possible chimeric state on organ-specific metabolic perturbations. Residual beta-mannosidase enzyme activity was found in plasma, kidney, liver and spleen but not in brain. Other lysosomal enzyme activities were comparable to normal values. Immunoreactive beta-mannosidase was estimated to be less than 10% of normal levels. Kidney, brain grey matter and brain white matter contained 33%, 12% and 4%, respectively, of the oligosaccharides expected in the organs of beta-mannosidosis animals. There were no detectable oligosaccharides or cytoplasmic vacuolation in the liver or spleen. Studies of this possible chimera provided preliminary evidence for the efficacy of prenatal treatment of early-onset neurodegenerative disorders.

The combination of normal phase with reversed phase high performance liquid chromatography for the analysis of asparagine-linked neutral oligosaccharides labelled with p-aminobenzoic ethyl ester

We have developed a novel approach for the analysis of asparagine-linked neutral oligosaccharides derived from glycoproteins. The oligosaccharides are labelled with p-aminobenzoic ethyl ester and the derivatives are separated on two high performance liquid chromatographic columns, one containing amide-silica and the other containing octadecyl-silica. The elution positions of 39 different ABEE-oligosaccharides on the two columns were plotted on a two-dimensional map. Unique non-overlapping positions of these oligosaccharides demonstrate that this technology would be useful for the identification of Asn-linked oligosaccharides at high sensitivity.

Oligosaccharides accumulated in the bovine beta-mannosidosis kidney

The phenotype of bovine beta-mannosidosis (beta-mannosidase deficiency), recently identified in Salers cattle, is similar to the caprine form of the disease (Abbitt et al., 1991). This investigation was designed to characterize accumulated kidney oligosaccharides in bovine beta-mannosidosis. Oligosaccharides were extracted from the kidney of an affected Salers calf and purified by chromatographic techniques. The amount of accumulating oligosaccharides in 1 g of wet tissue was about 21 mumol. Structures of derivatized oligosaccharides were characterized by high-performance liquid chromatography, mass spectrometry, methylation analysis and sequential exoglycosidase digestions. The major accumulating oligosaccharides were Man beta 1-4GlcNAc and Man beta 1-4GlcNAc beta 1-4GlcNAc. Oligosaccharides accumulating in minor amounts were Man beta 1-4GlcNAc beta 1-4Man beta 1-4GlcNAc, Man alpha 1-6Man beta 1-4GlcNAc beta 1-4GlcNAc and Man beta 1-4GlcNAc beta 1-4Man beta 1-4GlcNAc beta 1-4GlcNAc. As in caprine beta-mannosidosis, oligosaccharides with terminal beta-mannose residues and cleaved as well as uncleaved chitobiose linkages were identified in bovine beta-mannosidosis kidney. The accumulating oligosaccharides in tissue were thus identical in bovine and caprine beta-mannosidosis; however, the source of the novel oligosaccharides remains to be determined.

Further characterization of allergenically active oligosaccharitols isolated from a sea squirt H-antigen

Complete primary structures of five allergenically active oligosaccharitols (HPG-beta 2-N5a, -N6, -N7a, -N7b, and -N9) derived from a sea squirt H-antigen were studied. Structural characterization was carried out by a new method in which products of limited periodate oxidation, followed by derivatization with p-aminobenzoic acid ethyl ester, were analyzed by a combination of HPLC, fast atom-bombardment mass spectrometry, sequential glycosidase digestion, methylation analysis, and 500-MHz 1H NMR. Established structures of GalNAc beta 1-4 (GalNAc alpha 1-2Fuc alpha 1-3) GlcNAc beta 1-3GalNAc-ol, GalNAc beta 1-4GlcNAc beta 1-3 (GalNAc beta 1-4GlcNAc beta 1-6) GalNAc-ol, GalNAc beta 1-4GlcNAc beta 1-3[GalNAc beta 1-4 (Fuc alpha 1-3) GlcNAc beta 1-6] GalNAc-ol, GalNAc beta 1-4 (Fuc alpha 1-3) GlcNAc beta 1-3[GalNAc beta 1-4 (Fuc alpha 1-3) GlcNAc beta 1-6] GalNAc-ol, and GalNAc beta 1-4 (GalNAc alpha 1-2Fuc alpha 1-3)GlcNAc beta 1-3 [GalNAc beta 1-4 (GalNAc alpha 1-2Fuc alpha 1-3)GlcNAc beta 1-6]GalNAc-ol are represented by HPG-beta 2-N5a, -N6, -N7a, -N7b, and -N9, respectively. These structures have not been encountered previously. Oligosaccharide units GalNAc alpha 1-2Fuc alpha 1-, GalNAc beta 1-4GlcNAc beta 1-, and Fuc alpha 1-3GlcNAc beta 1- are considered to be the allergenically specific epitopes. Partial assignments of 500-MHz 1H NMR spectra of these novel O-linked oligosaccharitols were attempted.

Structures of asparagine-linked oligosaccharides from hen egg-yolk antibody (IgY). Occurrence of unusual glucosylated oligo-mannose type oligosaccharides in a mature glycoprotein

Asparagine-linked oligosaccharides present on hen egg-yolk immunoglobulin, termed IgY, were liberated from the protein by hydrazinolysis. After N-acetylation, the oligosaccharides were labelled with a UV-absorbing compound, p-aminobenzoic acid ethyl ester (ABEE). The ABEE-derivatized oligosaccharides were fractionated by anion exchange, normal phase and reversed phase HPLC, and their structures were determined by a combination of sugar composition analysis, methylation analysis, negative ion FAB-MS, 500 MHz 1H-NMR and sequential exoglycosidase digestions. IgY contained monoglucosylated oligomannose type oligosaccharides with structures of Glc alpha 1-3Man7-9-GlcNAc-GlcNAc, oligomannose type oligosaccharides with the size range of Man5-9GlcNAc-GlcNAc, and biantennary complex type oligosaccharides with core region structure of Man alpha 1-6(+/- GlcNAc beta 1-4)(Man alpha 1-3)Man beta 1-4GlcNAc beta 1-4(+/- Fuc alpha 1-6)GlcNAc. The glucosylated oligosaccharides, Glc1Man8GlcNAc2 and Glc1Man7GlcNAc2, have not previously been reported in mature glycoproteins from any source.

Purification and characterization of a major glycoprotein in rat liver lysosomal membrane

A major lysosomal membrane glycoprotein (LGP107) which has an apparent molecular weight (Mr) of 107 kilodaltons (kDa) was purified from rat liver by a simple method with a yield of 1 mg/87 g wet weight of liver. The purification procedures include; preparation of tritosomal membranes of triton-filled lysosomes (tritosomes), extraction of tritosomal membranes by Lubrol PX, wheat germ agglutinin (WGA)-Sepharose affinity chromatography, and monoclonal antibody-Sepharose affinity chromatography. The quantitative immunoblot analysis indicated that LGP107 represents 6.2% of the total protein of tritosomal membranes. The isoelectric point of the purified glycoprotein was 2.7, and it moved toward neutral pH after sialidase treatment, with its molecular weight decreased by about 10 kDa. LGP107 contained 52% carbohydrates, and the carbohydrate moiety was compared of Fuc, Man, Gal, GlcNAc and sialic acid in a molar ratio of 7.2:68.2:40.6:63.0:32.3, respectively, indicating that LGP107 was highly glycosylated with N-linked complex-type olgosaccharide chains. Out of the N-linked glycans released from the glycoprotein by hydrazinolysis/N-reacetylation, about 70% was sialylated. Anion exchange and reverse-phase high performance liquid chromatography analysis on the structure of N-glycans revealed that a disialyl biantennary form is a major component in the oligosaccharide chains of LGP107.

Structure of an allergenic pentasaccharitol, Gp-1 beta-b6, isolated from a sea squirt antigen, Gi-rep, as a minimum structural unit responsible for its allergenicity

An allergenic pentasaccharitol, Gp-1 beta-b6, was isolated as a minimum structural unit responsible for the allergic reaction in skin of patients with sea squirt allergy from a saccharitol fraction, Gp-1 beta-b, that had been liberated by beta-elimination from a glycopeptide in a Pronase digest of a sea squirt antigen, Gi-rep. Methylation/GC-MS and FAB-MS analyses indicated the sugar sequence of Gp-1 beta-b6 to be GalNAcl----2Fucl----(GalNAc1----) 3,4GlcNAc1----3GalNAc-ol. To analyze the structure in more detail, Gp-1 beta-b6 was labeled with p-aminobenzoic acid ethyl ester (ABEE), i.e., the reducing terminal 3-O-substituted GalNAc-ol of the saccharitol was oxidized to 2-O-substituted L-ThrNAc with equimolar periodate, and the resultant aldehyde was labeled with ABEE by reductive amination. The ABEE-labeled Gp-1 beta-b6 was subjected to sequential exoglycosidase digestion with beta-N-acetylhexosaminidase, alpha-N-acetylgalactosaminidase, and alpha-fucosidase, and the digests were chromatographed on an HPLC column of TSK gel Amide 80. From the results of the HPLC, methylation/GC-MS, and FAB-MS analyses of the digests of the labeled substrate, the structure of Gp-1 beta-b6 was determined to be GalNAc alpha 1----2Fuc alpha 1----3(GalNAc beta 1----4)GlcNAc beta 1----3GalNAc-ol. Enzymatic elimination of either the non-reducing terminal beta-GalNAc or the non-reducing terminal alpha-GalNAc led to inactivation of the allergenic pentasaccharitol. Accordingly, it is possible that the allergenic saccharitol contains two disaccharide units as the allergy-specific epitopes, one GalNAc alpha 1----2Fuc alpha 1---- and the other GlcNAc beta 1----4GLcNAc beta 1----.

Hearing of forest workers with vibration-induced white finger: a five-year follow-up

To examine the association between vibration-induced white finger (VWF) and hearing loss, 108 male forest workers who regularly used vibrating tools were followed up for five years. Case-control pairs matched for initial age and hearing level and exposure time to noise during the study period were selected from men with and without VWF. The hearing levels significantly worsened during the follow-up period at 2, 4 and 8 kHz in the affected cases but only at 8 kHz in the controls. Since threshold shift at 4 kHz, which is a typical effect of noise exposure, was significant only in the affected cases, it is suggested that the hearing of people with VWF was more vulnerable to noise. A pathological change causing VWF might also increase the susceptibility of hearing to noise damage.

Quantification of urinary glucose and protein with test-strips through reflectometric analysis

Reflectometric measurement of urine test-strips, using the Urotron RL9, was employed to quantify urinary glucose and protein. Although the test-strips (Combur-9-Test) are designed for qualitative use, the reflectance intensities determined by the Urotron RL9 are applicable to quantitative analysis. Reflectance quantitation and conventional colorimetric methods were closely correlated for glucose (r = 0.953) and protein (r = 0.906). Intra-assay coefficients of variation of reflectance value were less than 5%. The negative influence of ascorbic acid on glucose determination was defined quantitatively. A significant positive interference from hemoglobin on protein determination was also demonstrated, but effectively eliminated after compensating for urine color.

Structural studies of sialylated oligosaccharides of human midcycle cervical mucin

It was previously shown that reductive alkali treatment of purified human cervical mucin releases a heterogeneous population of reduced neutral, sialylated, and sulfated oligosaccharides (Yurewicz, E. C., and Moghissi, K. S. (1981) J. Biol. Chem. 256, 11895-11904). Four major sialylated oligosaccharide fractions were isolated with approximate compositions of Fuc:GlcNac:Gal:NeuAc:N-acetylgalactosaminitol (GalNAcol) = 0:0:0:1:1 (B1a), 0:0:1:1:1 (B2b), 0:1:2:1:1 (B3a), and 1:1:2:1:1 (B4a), where Fuc is fucose. They comprised roughly 3, 11, 7, and 6% of recovered oligosaccharide chains, respectively. On the basis of periodate oxidations, methylation analyses, and sequential degradations with glycosidases, the following structures were determined. (Formula: see text) Oligosaccharides 1 and 2 are characterized by the presence of N-acetylneuraminic acid in alpha 2,6-linkage to N-acetylgalactosaminitol. The remaining oligosaccharides contain N-acetylneuraminic acid in alpha 2,3-linkage to galactose residues. Oligosaccharides 3 and 4 and oligosaccharides 5 and 6 were isolated as unresolved isomeric mixtures in fractions B3a and B4a, respectively. Oligosaccharides 3 and 4 were distinguished on the basis of susceptibility to digestion with Aspergillus niger beta-galactosidase whereas oligosaccharides 5 and 6 were distinguished on the basis of differential rates of digestion with beef kidney alpha-fucosidase. The structural data indicate the presence of at least two sialyltransferases in human cervical epithelium and further suggest a potential physiologically significant competition between sialyltransferase and beta-N-acetylglucosaminyltransferase for C-6 of the N-acetylgalactosamine residue O-glycosidically linked to serine/threonine of the polypeptide core.

Structural characterization of novel complex oligosaccharides accumulated in the caprine beta-mannosidosis kidney. Occurrence of tetra- and pentasaccharides containing a beta-linked mannose residue at the nonreducing terminus

Four oligosaccharide fractions were isolated and purified from the kidney of goats affected with beta-mannosidosis by repeating Bio-Gel P-2 column chromatography. The structural characterization of the purified oligosaccharide fractions (oligosaccharides A, B, C1,2, and D) included sugar composition analysis by gas chromatography, sugar sequence analysis by mass spectrometry of their permethylated alditols, and by methylation analysis as well as anomeric configuration studies by exoglycosidase digestions. Oligosaccharides A and B were the major oligosaccharides accumulating in the kidney and were elucidated as Man beta 1-4GlcNAc and Man beta 1-4GlcNAc beta 1-4GlcNAc, respectively (Matsuura, F., Laine, R. A., and Jones, M. Z. (1981) Arch. Biochem. Biophys. 211, 485-493). Oligosaccharide C1,2 was a mixture of two tetrasaccharides and oligosaccharide D was a pentasaccharide. The proposed structures are: oligosaccharide C1, Man beta 1-4GlcNAc beta 1-4Man beta 1-4GlcNAc; oligosaccharide C2, Man alpha 1-6Man beta 1-4GlcNAc beta 1-4GlcNAc; oligosaccharide D, Man beta 1-4GlcNAc beta 1-4Man beta 1-4GlcNAc beta 1-4GlcNAc. Tetrasaccharide C1 and pentasaccharide D are heretofore undiscovered oligosaccharides. There is no precedent for these structures in glycoproteins or other glycoconjugates. One possibility which accounts for the presence of oligosaccharide C1 and D is that a bisecting N-acetylglucosamine (the beta-N-acetylglucosamine residue linked at the C-4 position of the beta-mannosyl residue of the trimannosyl core of the asparagine-linked sugar chains) is linked by a beta-mannosyl residue. Moreover, the detection of oligosaccharides containing two N-acetylglucosamine residues at the reducing terminus, together with those containing a single N-acetylglucosamine residue, is further corroboration of species-specific differences in glycoprotein catabolic pathways (Hancock, L. W., and Dawson, G. (1984) Fed. Proc. 43, 1552) or in glycoprotein structures.

Electron ionization mass spectra of reduced and permethylated urinary oligosaccharides from patients with mannosidosis

The electron ionization mass spectra of reduced and permethylated isomeric mixtures of the major urinary tri- to deca-oligosaccharides of patients with mannosidosis are reported. Many of the oligosaccharide isomers can be differentiated in the mixtures on the basis of their distinct fragmentation patterns.

Substrate specificity of D-galactose oxidase. Evidence for the oxidation of internally linked galactosyl residues of Helix pomatia galactogen

Linkage analysis of the carbohydrate portion of glycoproteins and glycolipids is widespread. Sequential treatment with D-galactose oxidase and tritiated borohydride is a standard method for incorporation of radioactive marker into what has been assumed to be exclusively terminal residues of D-galactose or N-acetyl-D-galactosamine. The data presented here establishes the ability of D-galactose oxidase to act upon a specific subterminal D-galactosyl residue, [----2)-D-Gal(1----], as well as upon terminal nonreducing galactosyl residues. Helix pomatia galactogen, a high molecular weight galactose homopolymer, was sequentially treated with D-galactose oxidase and tritiated borohydride. The 3H-galactogen was recovered and analyzed to determine which galactosyl units carried radioactive label. After complete methylation and then acid hydrolysis of 3H-galactogen, its partially methylated galactosyl components were reduced and acetylated for identification by gas chromatography and mass spectroscopy. Radioactivity was located by collection of effluent fractions during gas chromatography. The only subterminal residue to be labeled was the 2-linked D-galactose, although another with a free oxidizable 6-carbon was present, 3-linked D-galactose, [----3)-D-Gal(1----]. Linkage analysis of internal radiolabeled galactosyl residues could be used to detect changes in saccharide structure during cellular events.