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Nagarajan S, Chen HC, Li SC, Li YT, Lockyer JM. Evidence for two cDNA clones encoding human GM2-activator protein. Biochem J 1992; 282 ( Pt 3):807-13. [PMID: 1554364 PMCID: PMC1130859 DOI: 10.1042/bj2820807] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Two cDNAs encoding GM2 activator, pGM2A (648 bp) and GAP (1093 bp), were isolated from human placenta lambda gt11 libraries. The DNA sequence of pGM2A from 1 to 302 was almost identical with GAP, but diverged from 303-648. PCR was used to demonstrate the presence of both species of GM2 activator in placental RNA. Both cDNAs hybridized to mRNAs of approximately 2.3 kb and to identical single bands on genomic Southern blots.
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Qin H, Li SC. [Case control study on risk factors of cerebral thrombosis]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1991; 12:354-6. [PMID: 1811895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In order to explore the pathogenic risk factors or protective factors of cerebral thrombosis, 1:1 matched case control study was done in 110 cases diagnosed by computerized tomography (CT). Both cases and controls were selected from several provincial and municipal hospitals in Jinan, Shandong Province, China. Every case was matched with one control on sex, race, age, occupation, residential area, educational level and economic status. 31 factors were analysed and 9 risk or protective factors were found by univariate analysis and multiple stepwise regression. Using the same 9 factors as independent variables, conditional logistic regression was performed and 4 factors were confirmed as pathogenic risk factors or protective factor of cerebral thrombosis (alpha = 0.01). They are high blood pressure (beta = 3.46, OR = 7.57), abdominal skinfold thickness (beta = 3.21, OR = 3.77), familial aggregation of stroke (beta = 2.25, OR = 12.64) and high level HDL2-C (beta = -2.99, OR = 0.16). Moreover, reliability of collective data and control o: bias were evaluated and discussed.
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Banerjee P, Siciliano L, Oliveri D, McCabe NR, Boyers MJ, Horwitz AL, Li SC, Dawson G. Molecular basis of an adult form of beta-hexosaminidase B deficiency with motor neuron disease. Biochem Biophys Res Commun 1991; 181:108-15. [PMID: 1720305 DOI: 10.1016/s0006-291x(05)81388-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A patient (KL) with progressive motor neuron disease associated with partial Hex A (alpha beta) and no Hex B (beta beta) activity, synthesized beta-chains which only associated with alpha-chains. To identify the molecular basis of this inability of beta-chains to self associate, RNA from cultured fibroblasts was reverse transcribed, the cDNA encoding the beta-chain amplified by polymerase chain reaction, subcloned, and sequenced to reveal two types of single missense mutation. The first mutation, (Type I) 619A----G, was paternally inherited and converted a 207IIe----Val in a highly conserved region believed to be associated with catalytic activity and activator protein binding. Biochemical evidence for impaired activator protein binding was obtained by purifying Hex A from KL urine and demonstrating a greater than 50% reduction of in vitro GM2 hydrolysis compared to normal urinary Hex A. In other cDNA species (Type II), a maternally inherited 1367A----C mutation converted 456Tyr----Ser in another highly conserved region of the beta-chain and we propose that this mutation leads to the inability of the beta-chains to self associate and thus reach maturity. These same cDNA species contained a second 362A----G mutation which converted 121Lys----Arg, but is apparently a polymorphism since it also occurs in some normal subjects. We propose that the patient is a compound heterozygote in which a combination of no self-association of the mutant beta-chains and impaired activator protein binding to alpha-beta (mutant) (Hex A) required for GM2 hydrolysis result in total beta-Hex B deficiency and slow accumulation of GM2 ganglioside, primarily in motor neurons.
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Rothman P, Li SC, Gorham B, Glimcher L, Alt F, Boothby M. Identification of a conserved lipopolysaccharide-plus-interleukin-4-responsive element located at the promoter of germ line epsilon transcripts. Mol Cell Biol 1991; 11:5551-61. [PMID: 1922063 PMCID: PMC361925 DOI: 10.1128/mcb.11.11.5551-5561.1991] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Treatment of splenic B lymphocytes and certain B-lineage cell lines with the mitogen lipopolysaccharide (LPS) and the lymphokine interleukin-4 (IL-4) induces expression of germ line immunoglobulin C epsilon transcripts and class switching to the C epsilon gene. We show that LPS-plus-IL-4 induction of germ line epsilon transcripts (termed I epsilon transcripts) occurs at the transcriptional level in an Abelson murine leukemia virus-transformed pre-B-cell line. A 1.1-kb region of DNA surrounding the I epsilon promoter endows inducible transcription to a heterologous reporter gene stably transfected into these cells; such inducible expression depends on combined treatment with LPS and IL-4. Analyses of constructs transiently introduced into a B-cell lymphoma line demonstrated that LPS-plus-IL-4-inducible expression can be conferred by a 179-bp segment of DNA spanning the I epsilon transcriptional initiation site. Mutational analyses demonstrated that this expression depended on DNA sequences within a conserved region directly upstream from the I epsilon transcriptional initiation region. One nuclear protein that is constitutively expressed in normal B cells binds to the downstream end of the conserved sequence; its binding specificity correlates with the functional effect of several mutations. Two additional proteins, which are induced by IL-4 treatment of splenic B cells, bind to the transcription initiation sites of I epsilon. These proteins are indistinguishable in binding assays from proteins previously shown to bind an enhancer region of the class II major histocompatibility complex gene A alpha.
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Li SC, Bowes G, Ioannides-Demos LL, Spicer WJ, Hooper RE, Spelman DW, Tong N, McLean AJ. Dosage adjustment and clinical outcomes of long-term use of high-dose tobramycin in adult cystic fibrosis patients. J Antimicrob Chemother 1991; 28:561-8. [PMID: 1761450 DOI: 10.1093/jac/28.4.561] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A two-phase study was undertaken designed to investigate the impact of computer-aided drug monitoring on tobramycin concentrations and clinical outcomes in adult patients with cystic fibrosis. In phase one, a baseline (historical control) study of drug use patterns was performed. During the second phase, patients admitted for intravenous treatment with tobramycin for acute exacerbations of pseudomonal pulmonary infections were randomly allocated to one of two schedules. Group A patients had tobramycin dosage regimens decided by clinicians based on pre-existing protocols using serum tobramycin assay data determined three times weekly. Group B patients had dosage regimens determined by a computerized pharmacokinetic predictive program using both population-based pharmacokinetic parameter estimation and fitting of serum concentration-time data using Bayesian regression. The agreed therapeutic target was a peak serum tobramycin concentration of 8-10 mg/L and a trough concentration of 1-2 mg/L. There was a major difference between the two groups comparing the number of paired trough and peak concentrations within the target concentration ranges (group A-14%; group B-34.7%, chi 2 test, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
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Zhao F, Emoto SE, Lavine L, Nelson KB, Wang CC, Li SC, Cheng XM, Bolis CL, Schoenberg BS. Risk factors for febrile seizures in the People's Republic of China: a case control study. Epilepsia 1991; 32:510-4. [PMID: 1868808 DOI: 10.1111/j.1528-1157.1991.tb04685.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A case control study was conducted to investigate the association of family history of febrile seizures (FS) and history of maternal, pregnancy and delivery, and postnatal factors with FS. Information was gathered by door-to-door survey in six major cities in the People's Republic of China. Factors present before the date of onset of FS were assessed in 182 subjects and in an equal number of controls matched for age, sex, and geographic area. The odds ratio for risk of FS in children with a family history of FS in a first-degree relative was 10.0 (confidence interval 2.7-58.6), confirming other observations that familial factors are an important predisposing characteristic for FS. Maternal acute respiratory infection during the first trimester of pregnancy was slightly more frequent in children with FS (odds ratio, 1.9 confidence interval 1.0-3.9). None of the other examined pregnancy or delivery factors was associated with an increased risk, suggesting that birth history is not an important factor predisposing to FS.
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232
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Li YT, Carter BZ, Rao BN, Schweingruber H, Li SC. Synthesis of neoglycoconjugates using oligosaccharide transferring activity of ceramide glycanase. J Biol Chem 1991; 266:10723-6. [PMID: 2040590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Ceramide glycanase (CGase) isolated from the leech Macrobdella decora was found to transfer the oligosaccharide en bloc from various glycosphingolipids to suitable acceptors. For example, CGase transferred the intact II3NeuAcGgOse4 from GM1 to 4-phenyl-1-butanol, 1,8-octanediol and various 1-alkanols having a chain length of six or more carbons. Among various 1-alkanols, 1-octanol was found to be the best acceptor. In an incubation mixture of 50 microliters containing 30 nmol of GM1, 50 micrograms of sodium cholate, 20 microliters of 1-octanol, and 0.1 unit of CGase, the ratio between hydrolysis and transglycosylation was approximately 3:1. Negative fast atom bombardment-mass spectral analysis of the enzymatically synthesized octyl-II3NeuAcGgOse4 showed a mass ion at m/z 1109.7 for the parent ion, consistent with its expected mass. NMR analysis of the enzymatically synthesized octyl-II3NeuAcGgOse4 showed that the Glc residue is linked to the octanol through a beta-linkage. Vicinal coupling constants of the ring protons of the sugar residues indicate that their pyranose ring geometries are not affected by the transferase activity. CGase also transferred the oligosaccharide from GM1 to CF3CO-NH(CH2)5CH2OH, (CH3)3CO-CO-NH(CH2)5CH2OH, (HOCH2)3C-NHCO-(CH2)4-COOMe, CH2 = CH-(CH2)7CH2OH and 1,2:3,4-di-O-isopropylidene-D-galactopyranose. The oligosaccharide transferring reaction carried out by CGase should become useful for the synthesis of neoglycoconjugates to study the biological functions expressed by glycan chains in glycosphingolipids.
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Ko YC, Li SC, Yen YY, Yeh SM, Hsieh CC. Horizontal transmission of hepatitis B virus from siblings and intramuscular injection among preschool children in a familial cohort. Am J Epidemiol 1991; 133:1015-23. [PMID: 2035502 DOI: 10.1093/oxfordjournals.aje.a115810] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The authors followed 147 children from 113 families who were susceptible to hepatitis B virus infection for a total of 275 person-years. Among these children, 19 became infected with the hepatitis B virus and thus became new subclinical cases. In this cohort study, parents played a minor role in hepatitis B virus horizontal transmission. On the other hand, the estimated incidence rate ratio of hepatitis B virus infection for siblings of a hepatitis B e antigen (HBeAg) carrier was 2.8 (95% confidence interval 1.1-7.4) when compared with those children without a HBeAg sibling carrier as analyzed by multiple logistic regression. The adjusted incidence rate ratio among siblings increased with increased number of HBeAg carriers. In addition, intramuscular injections played an important role in hepatitis B virus transmission in children. It was found that 61.8% (170/275 person-years) of the children had received intramuscular injections. Most of the injections were administered at private clinics over a 2-year period. Hepatitis B virus infection showed a correlation with injection (adjusted incidence rate ratio = 3.3, 95% confidence interval 1.1-9.5) and with frequency of injections. The authors concluded that HBeAg was a valuable marker for infectivity in hepatitis B virus horizontal transmission. Furthermore, the authors found that hepatitis B virus infection is independently transmitted from sibling to sibling, and by iatrogenic injections because improperly sterilized syringes were shared in areas where hepatitis B is prevalent and intramuscular injection is common.
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Li SC, Rothman P, Boothby M, Ferrier P, Glimcher L, Alt FW. Control of immunoglobulin heavy chain constant region gene expression. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1991; 292:245-51. [PMID: 1950776 DOI: 10.1007/978-1-4684-5943-2_27] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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235
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Li YT, Nakagawa H, Ross SA, Hansson GC, Li SC. A novel sialidase which releases 2,7-anhydro-alpha-N-acetylneuraminic acid from sialoglycoconjugates. J Biol Chem 1990; 265:21629-33. [PMID: 2254319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The leech (Macrobdella decora) was found to contain two sialic acid-cleaving enzymes: an ordinary sialidase and a novel sialic acid-cleaving enzyme. This novel enzyme released 2,7-anhydro-alpha-N-acetylneuraminic acid (Neu2,7-anhydro5Ac) instead of alpha-N-acetylneuraminic acid (Neu5Ac) from 4-methylumbelliferyl-Neu5Ac, glycoproteins, and gangliosides. We have partially purified this novel sialidase from M. decora. We have also isolated Neu2,7-anhydro5Ac released from 4-methylumelliferyl-Neu5Ac and whale nasal keratan sulfate in pure form. The novel sialidase produced Neu2,7-anhydro5Ac only from sialoglycoconjugates, but not from free Neu5Ac. The structure of Neu2,7-anhydro5Ac produced by the novel sialidase was established by chemical analysis, mass spectrometry, and NMR spectroscopy. NMR analysis showed that instead of the original 2C5 conformation, the pyranose ring of Neu2,7-anhydro5Ac was in the 5C2 conformation, which makes the formation of the 2,7-anhydro bridge possible.
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Li YT, Nakagawa H, Ross SA, Hansson GC, Li SC. A novel sialidase which releases 2,7-anhydro-alpha-N-acetylneuraminic acid from sialoglycoconjugates. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)45787-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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237
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Mason-Garcia M, Beckman BS, Brookins JW, Powell JS, Lanham W, Blaisdell S, Keay L, Li SC, Fisher JW. Development of a new radioimmunoassay for erythropoietin using recombinant erythropoietin. Kidney Int 1990; 38:969-75. [PMID: 2266682 DOI: 10.1038/ki.1990.299] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of a 24 hour radioimmunoassay for erythropoietin (EPO) using EPO derived from recombinant DNA as both immunogen and ligand is described in the present paper. Mixed breed rabbits immunized with 10 micrograms/kg of EPO derived from a stably transfected cell line (Elanex Pharmaceuticals Inc., Bothel, Washington, USA, through McDonnell Douglas Corp., St. Louis, Missouri, USA; "MD") produced antibodies to EPO with high titer (up to 1:896,000 final dilution in the tube), high affinity (8.4 x 10(11) liter/M), and good specificity. Purified EPO from the above source or from AmGen Biologicals (Thousand Oaks, California, USA; "AG") were successfully radioiodinated with the chloramine-T method and used as ligand in the radioimmunoassay. Standard dose-response curves prepared with EPO from both commercial sources were not significantly different and showed a sensitivity of 0.75 to 0.96 mU/tube. The dose-response curves in both systems also showed parallelism with serially diluted serum from a patient with aplastic anemia. Within-assay and between-assay precision were determined by assaying multiple replicates of a serum pool. Recovery of exogenous EPO added to a serum pool averaged 97% for both systems. The range of normal human serum EPO was determined by assaying the sera of 153 hematologically-normal adult subjects and was found to be 1.1 to 27.3 mU/ml for MD EPO and 0.5 to 16.7 mU/ml for AG EPO. Sera from several patients with hematologic abnormalities were also assayed, including those of 36 patients with anemia of end-stage renal disease (mean +/- SEM, 29.5 +/- 4.0 mU/ml; P less than 0.01). In conclusion, this new, more rapid and sensitive radioimmunoassay system can be used to measure EPO levels in sera from normal human subjects and patients with several types of anemia, and should also be very useful in therapeutic drug monitoring of patients receiving EPO from various commercial sources.
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Ferrier P, Covey LR, Li SC, Suh H, Malynn BA, Blackwell TK, Morrow MA, Alt FW. Normal recombination substrate VH to DJH rearrangements in pre-B cell lines from scid mice. J Exp Med 1990; 171:1909-18. [PMID: 2112584 PMCID: PMC2187946 DOI: 10.1084/jem.171.6.1909] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
To further analyze the VDJ recombination defect in lymphoid pre-B cells from mice with severe combined immune deficiency (scid mice), we have assayed the ability of Abelson murine leukemia virus (A-MuLV) transformed pre-B cells from scid mice to rearrange a recombination substrate in which inverted VH to DJH joins activate a selectable (gpt) gene. In unselected populations, substrate rearrangements occurred frequently, but were aberrant and probably analogous to the aberrant rearrangements observed at endogenous scid Ig gene loci. In contrast, populations of scid pre-B lines selected for gpt activity within the substrate contained mostly "normal" VH to DJH joins within the introduced substrate. These findings demonstrate that scid pre-B cells can make normal joins at low efficiency and are discussed with respect to the potential mechanism of the scid defect and the occurrence of Igs in leaky scid mice.
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Yancopoulos GD, Nolan GP, Pollock R, Prockop S, Li SC, Herzenberg LA, Alt FW. A novel fluorescence-based system for assaying and separating live cells according to VDJ recombinase activity. Mol Cell Biol 1990; 10:1697-704. [PMID: 2320007 PMCID: PMC362275 DOI: 10.1128/mcb.10.4.1697-1704.1990] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We describe two retroviral vector-based recombination substrate systems designed to assay for lymphoid VDJ recombinase activity in cultured cells. Both substrates incorporate a constitutive dominant marker gene (the simian virus promoter-driven neo gene) to allow selection of cells that stably integrate the substrate. Both substrates also include a second marker gene that becomes transcriptionally active only when inverted by a site-specific recombination event between flanking immunoglobulin variable-region gene segments. The first vector, similar in structure to previous retrovirus-based recombination substrates, utilizes the bacterial guanine-xanthine phosphoribosyltransferase gene (gpt) as its activatable marker; detection of inversion (VDJ recombinase activity) involves drug selection and Southern blotting analyses. We have used this vector to make a more extensive and quantitative survey of VDJ recombinase activity in B-lineage cell lines than has previously been performed with stable substrates, and we have compared our results with those of other studies that use transient recombination substrates. In the second vector, the activatable gene is the bacterial beta-galactosidase gene (lacZ). Detection for inversional activation of this gene is achieved by a fluorogenic assay, termed FACS-Gal, that detects beta-galactosidase activity in viable cells. The latter assay has the unique advantage of rapidly detecting cells that undergo recombination and also allows viable sorting of cells on the basis of the presence or absence of VDJ recombinase activity. We have used the lacZ vector to rapidly quantitate VDJ recombinase activity in B-lineage cell lines and compared the results with those obtained with the gpt vector. We have also used the lacZ vector to isolate variant pre-B-cell lines with low and high levels of VDJ recombinase activity.
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Rothman P, Chen YY, Lutzker S, Li SC, Stewart V, Coffman R, Alt FW. Structure and expression of germ line immunoglobulin heavy-chain epsilon transcripts: interleukin-4 plus lipopolysaccharide-directed switching to C epsilon. Mol Cell Biol 1990; 10:1672-9. [PMID: 2157139 PMCID: PMC362272 DOI: 10.1128/mcb.10.4.1672-1679.1990] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We have isolated cDNA clones complementary to a truncated immunoglobulin heavy-chain C epsilon RNA transcript previously found to be induced in B lymphoid cells by treatment with lipopolysaccharide (LPS) combined with interleukin-4 (IL-4). We demonstrate that this transcript initiates from a promoter upstream of the germ line epsilon class-switch recombination region (S epsilon region). The major germ line C epsilon transcript contains a small 5' exon contributed by sequences upstream of the S epsilon region spliced to the normal C epsilon exons. Treatment of splenic B lymphoid cells with LPS plus IL-4 induces the expression of transcripts from the germ line epsilon transcription unit followed by expression of normal immunoglobulin epsilon heavy-chain mRNA. Furthermore, we demonstrate that similar treatment of transformed precursor B cell lines induces the expression of germ line epsilon transcripts followed by class switching to epsilon expression in these lines. This is the first demonstration of switching to epsilon in cells of the pre-B stage. The general structure of the germ line epsilon transcript and transcription unit is similar to that previously characterized for germ line gamma 2b transcripts. However, expression of these two germ line transcription units in B-lineage cells is inversely regulated by IL-4 (plus LPS) treatment, correlating with the effects of these treatments on switching to these loci.
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Li SC, Wang CC, Fu YG, Cheng XM, Feng EJ, Wang WJ, Shu Q, Yang QD, Chen SM, Su QG. Risk factors for stroke in rural areas of the People's Republic of China: results of a case-control study. Neuroepidemiology 1990; 9:57-67. [PMID: 2333124 DOI: 10.1159/000110752] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A case-control study on stroke was carried out in 1985 in conjunction with a prevalence survey on neurologic disorders in 22 rural communities of the People's Republic of China. 585 cases of stroke, detected from the survey, together with an equal number of matched controls were investigated. The statistically significant factors associated with stroke in this study were: hypertension (history, findings at examination); high salt intake; family member(s) with cerebrovascular disease and/or hypertension; heart disease (history, abnormal findings at examination); history of transient ischemic attacks, and arteriosclerotic funduscopic findings. These factors were analyzed separately for hemorrhagic and ischemic strokes.
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Rothman P, Li SC, Alt FW. The molecular events in heavy chain class-switching. Semin Immunol 1989; 1:65-77. [PMID: 15630960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Heavy chain class-switching is the process by which B lymphoid cells change the constant region of the immunoglobulin heavy chain they produce. Class-switching is most commonly accomplished by recombinationldeletion between switch recombination regions that lie upstream of each germline heavy chain constant region gene. Recent studies support a model that recombination to specific switch regions is directed by modulation of the accessibility of these regions to a common class-switch recombination system. T cell lymphokines seem to be able to alter the accessibility of different heavy chain constant region loci, and thereby direct the specificity of class-switch recombination in B cells.
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Li SC, Ioannides-Demos LL, Spicer WJ, Berbatis C, Spelman DW, Tong N, McLean AJ. Prospective audit of aminoglycoside usage in a general hospital with assessments of clinical processes and adverse clinical outcomes. Med J Aust 1989; 151:224-32. [PMID: 2761465 DOI: 10.5694/j.1326-5377.1989.tb115996.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A comprehensive, multiphasic review of gentamicin and tobramycin utilization was undertaken with audits of the microbiological sensitivity of Gram-negative pathogens; indications for the prescription of aminoglycoside agents; the utilization of assay services; the adequacy of clinical drug delivery by measures of serum antibiotic levels; and the assessment of adverse outcomes by markers of nephrotoxicity. The great majority of clinical isolates of target organisms (n = 4208) was more sensitive to gentamicin (96%) and to tobramycin (99%) than to all alternative agents, including first- and third-generation cephalosporin agents. A review of the indications for the prescription of aminoglycoside agents by clinical criteria showed that in 85.6% of 278 documented cases, the choice of agent was appropriate by clinical and microbiological criteria. In a substantial (77.6%) proportion of the 511 patients who were receiving therapeutic courses of an aminoglycoside agent, serum drug assays had been performed. Assay data could not be interpreted adequately in 52.6% of 3079 assayed cases as a result of inadequate data on administration regimens (39.7%) or sampling regimens (12.9%). Where sampling was documented adequately, there was extreme variation (zero to five hours) in post-dose sampling. In only 33.2% of cases could it be concluded unambiguously that the patients were receiving safer, adequate therapy for clinically significant infections, 5.6% of patients were receiving potentially toxic doses, and 8.6% of patients showed suboptimal concentration profiles. The majority of potentially toxic levels were associated with adverse effects.(ABSTRACT TRUNCATED AT 250 WORDS)
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Zhou B, Li SC, Laine RA, Huang RT, Li YT. Isolation and characterization of ceramide glycanase from the leech, Macrobdella decora. J Biol Chem 1989; 264:12272-7. [PMID: 2745442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have devised a simple method for achieving 890-fold purification of ceramide glycanase with 17% recovery from a North American leech, Macrobdella decora. The method includes water extraction, ammonium sulfate fractionation, and chromatography on octyl-Sepharose, Matrex gel blue A, and Bio-Gel A-0.5m columns. The final preparation showed one major protein band at 54 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. By using Bio-Gel A-0.5m filtration, the native enzyme was found to have a molecular mass of 330 kDa. With GM1 as substrate, the optimum pH of this enzyme was determined to be 5.0; the enzyme was stable between pH 4.5 and 8.5. Zn2+ at 5 mM and Cu2+, Ag+, and Hg2+ at 1 mM strongly inhibited the hydrolysis of GM1 by ceramide glycanase. The ceramide glycanase released the intact glycan chain from various glycosphingolipids in which the glycan chain is linked to the ceramide through a beta-glucosyl linkage. This enzyme also cleaved lyso-glycosphingolipids such as lyso-GM1 and lyso-LacCer and synthetic alkyl beta-lactosides. Among seven alkyl beta-lactosides tested, the enzyme only hydrolyzed the ones with an alkyl chain length of four or more carbons. The enzyme also hydrolyzed 2-(octadecylthio)ethyl O-beta-lactoside and 2-(2-carbomethoxyethylthio)ethyl O-beta-lactoside. p-Nitrophenyl, benzyl, and phytyl beta-lactosides, on the other hand, were not hydrolyzed. These results suggest that the enzyme can recognize the hydrophobic portion of glycolipid substrates. The fact that 2-(2-carbomethoxyethylthio)ethyl O-beta-N-acetyllactosaminide and DiGalCer were refractory to the enzyme indicated that in the substrate the first sugar attached to the hydrophobic chain cannot be N-acetylglucosamine and galactose. Furthermore, dodecyl maltoside, Gal alpha 1----6Glc beta Cer, and the LacCer in which the --CH2OH of the galactose was converted into --CHO were also resistant to the enzyme, and Man beta 1----4 Glc beta Cer was hydrolyzed at a much slower rate than LacCer. These results indicate that the nature and the linkage of the sugar attached to the glucose have a profound effect on the action of this enzyme. The hydrolysis of glycosphingolipids by ceramide glycanase is stimulated by bile salts. Among various bile salts tested, sodium cholate at a concentration of 1 microgram/microliter was found to be most effective in stimulating the hydrolysis of various glycosphingolipids with the exception of LacCer. For LacCer, sodium taurodeoxycholate at a concentration of 2-3 micrograms/microliters was most effective. Tween 20, Nonidet P-40, and Triton X-100 did not stimulate the hydrolysis of GM1.(ABSTRACT TRUNCATED AT 400 WORDS)
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DeGasperi R, Li YT, Li SC. Isolation and characterization of an activator protein for the hydrolysis of ganglioside GM2 from the roe of striped mullet (Mugil cephalus). Biochem J 1989; 260:777-83. [PMID: 2527497 PMCID: PMC1138744 DOI: 10.1042/bj2600777] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
After the revelation of the presence of ganglioside GM2 as the major ganglioside in the roe of striped mullet, Mugil cephalus [Li, Hirabayashi, DeGasperi, Yu, Ariga, Koerner & Li (1984) J. Biol. Chem. 259, 8980-8985], we have continued to investigate the catabolism of GM2 in this tissue. We have found that mullet roe contains a specific activator protein which stimulates the hydrolysis of GM2 carried out by the beta-hexosaminidase isolated from the same tissue. This activator has been purified by using conventional procedures including ammonium sulphate fractionation and chromatography on Sepharose 6B, DEAE-Sephadex A-50, octyl-Sepharose and Matrex Gel Blue A columns. This activator protein is also able to stimulate the hydrolysis of GM2 carried out by human beta-hexosaminidase A. Unlike human GM2-activator, the roe activator protein does not stimulate the hydrolysis of GgOse3Cer or GbOse4Cer. The molecular mass (18 kDa) of the roe activator protein was found to be similar to that of human GM2-activator; however, the pI (pH 4.1) was found to be lower than that of human GM2-activator. This is the first report on the presence of a GM2-activator protein in a source other than mammalian tissues.
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DeGasperi R, Li YT, Li SC. Presence of two endo-beta-N-acetylglucosaminidases in human kidney. J Biol Chem 1989; 264:9329-34. [PMID: 2498329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have isolated for the first time two kinds of endo-beta-N-acetylglucosaminidases (E-beta-GNases) simultaneously from human kidney. E-beta-GNase 1 was purified by water extraction, ammonium sulfate fractionation, and chromatography on Sephadex-G-200, DEAE-Sephadex, concanavalin A-Sepharose and Hypatite C columns. After the DEAE-Sephadex step, 107 units of E-beta-GNase 1 with a specific activity of 0.53 units/mg was obtained and after hydroxyapatite column, the enzyme recovery was 26 units with a specific activity of 10.4 units/mg. This enzyme hydrolyzed the high mannose-type asparaginylglycopeptide efficiently and had little activity toward the complex-type glycopeptide. This enzyme had an pH optimum at about 4.5 and was not inhibited by acetate ion. The Asn residue in a glycopeptide appeared not to be an important recognition site for E-beta-GNase 1 to express its activity because the acetylation or the dansylation of Asn residues as well as the elimination of Asn residue from the glycopeptide did not change the susceptibility of the oligosaccharide to E-beta-GNase 1. E-beta-GNase 2 was purified by water extraction, ammonium sulfate fractionation, and chromatography on Sephadex G-200, DEAE-Sephadex, concanavalin A-Sepharose, and Mono S columns. This enzyme was purified about 110-fold with 6.6% recovery. E-beta-GNase 2 was found to be a novel type of E-beta-GNase that hydrolyzed both the high mannose-type and the complex-type oligosaccharide with chitobiosyl group at the reducing end and without the Asn. E-beta-GNase 2 activity was found to be dependent on a L-aspartamido-beta-D-N-acetylglucosamine amidohydrolase (Asn-GNase) for the hydrolysis of asparaginylglycopeptide. Asn-GNase cleaved off the Asn residue from the glycopeptide, and the resulting oligosaccharide was hydrolyzed by E-beta-GNase 2. Because the acetylation or the dansylation of Asn residue in a glycopeptide rendered the glycopeptide resistant to Asn-GNase, the use of the modified asparaginylglycopeptide could not reveal the existence of E-beta-GNase 2 activity. The pH optimum of E-beta-GNase was found to be about 3.5. Like beta-hexosaminidases, this enzyme was inhibited by acetate ion, suggesting the recognition of GlcNAc moiety by this enzyme.
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Li SC. [The evaluation of lipoprotein as a screening test for coronary heart disease]. ZHONGHUA LIU XING BING XUE ZA ZHI = ZHONGHUA LIUXINGBINGXUE ZAZHI 1989; 10:167-71. [PMID: 2776196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Up to now there is no screening test suitable for coronary heart disease (CHD) among population. 38 cases of CHD diagnosed by electrocardiographic bicycle exercise and 71 cases with negative results as controls were studied concurrently to evaluate the screening test of CHD. According to the significant difference between the two groups, the ratio of TC/HDL-C.HDL-C/TC.LDL-C/HDL-C.HDL2-C/HDL3-C were selected to evaluate their validity and predictivity etc, on several cutoff vale respectively. TC/HDL-C and HDL2-C/HDL3-C were used in parallel to promote the detective value of CHD to 92%. TC/HDL-C was only selected in stepwise regression formula, so the positive likelihood of five-grade value of TC/HDL-C was calculated and different prior-test probability was estimated to predict the post-test probability of CHD. As a result cutoff value 3.2 of TC/HDL-C could be determined as atherogenic index in chinese population.
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Li SC. [A report on a feasibility test of "community control of epilepsy" proposed by WHO]. ZHONGHUA SHEN JING JING SHEN KE ZA ZHI = CHINESE JOURNAL OF NEUROLOGY AND PSYCHIATRY 1989; 22:144-7, 190. [PMID: 2512104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
According to a protocol proposed by the Division of Mental Health, WHO, a feasibility test for "Community Control of Epilepsy" was carried out in rural areas of Beijing and Sichuan. This project means to detect, control and follow-up patients with generalized tonic-clonic seizures using primary health care workers 40 patients were chosen to be administrated phenobarbital and divided randomly into two groups. 20 in community "A" treated by primary health care workers who were trained by a three-day course, 20 in community "B" treated by neurologists. Patients in both communities were compliant and the curative effects were no difference between the two groups. The primary health care workers could master the fixed method and manage patients conveniently. This present study revealed that the "Community Control of Epilepsy" is a feasible project in the rural areas of China.
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Li YT, Li SC. Ceramide glycanase from leech, Hirudo medicinalis, and earthworm, Lumbricus terrestris. Methods Enzymol 1989; 179:479-87. [PMID: 2695772 DOI: 10.1016/0076-6879(89)79147-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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