1101
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Killick-Kendrick R, Tang Y, Killick-Kendrick M, Johnson RN, Ngumbi PM, Sang DK, Lawyer PG. Phlebotomine sandflies of Kenya (Diptera: Psychodidae). III. The identification and distribution of species of the subgenus Larroussius. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1994; 88:183-96. [PMID: 8067814 DOI: 10.1080/00034983.1994.11812857] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The six species of phlebotomine sandflies of the subgenus Larroussius recorded in Kenya are Phlebotomus aculeatus, P. elgonensis, P. guggisbergi, P. longipes, P. orientalis and P. pedifer. Five are proven vectors of leishmaniasis in that country or elsewhere. Males of all six can be identified by the morphology of the aedeagus or the number and position of the hairs on the inner surface of the coxite. Additional features separating some of the species are the sizes of the palpal and antennal segments. The females have usually been considered difficult or impossible to distinguish. A comparison of the base of the spermathecal ducts is made and it is shown that all six can be identified by this character alone. A map of Kenya is given, showing the presently known distribution of the six Larroussius species. Further surveys are necessary in parts of the country that have not been systematically surveyed.
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1102
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Abstract
A new model is proposed based on signal transduction via G proteins for adaptation of the signal relay process in the cellular slime mold Dictyostelium discoideum. The kinetic constants involved in the model are estimated from Dictyostelium discoideum and other systems. A qualitative analysis of the model shows how adaptation arises, and numerical computations show that the model agrees with observations in both perfusion and suspension experiments. Several experiments that can serve to test the model are suggested.
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1103
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Gloor P, Tang Y, Kostanska A, Hamielec A. Chemical modification of polyolefins by free radical mechanisms: a modelling and experimental study of simultaneous random scission, branching and crosslinking. POLYMER 1994. [DOI: 10.1016/0032-3861(94)90946-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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1104
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Killick-Kendrick R, Killick-Kendrick M, Tang Y. Anthroponotic cutaneous leishmaniasis in Kabul, Afghanistan: the low susceptibility of Phlebotomus papatasi to Leishmania tropica. Trans R Soc Trop Med Hyg 1994; 88:252-3. [PMID: 8036692 DOI: 10.1016/0035-9203(94)90320-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Females of a laboratory colony of Phlebotomus papatasi from Kabul were fed through a membrane on a high dose of amastigotes of Leishmania tropica from the same place. Less than one-third of the flies became infected and only 6% developed heavy infections of the stomodaeal valve. From these observations, and previous studies by other workers, it is concluded that P. papatasi probably plays little or no part in the transmission of anthroponotic cutaneous leishmaniasis in Kabul. As in Saudi Arabia and Morocco, the most likely vector in Afghanistan is P. sergenti.
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1105
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Tang Y, Taylor KT, Sobieski DA, Medved ES, Lipsky RH. Identification of a human CD36 isoform produced by exon skipping. Conservation of exon organization and pre-mRNA splicing patterns with a CD36 gene family member, CLA-1. J Biol Chem 1994; 269:6011-5. [PMID: 7509795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
During an examination of different cell types for CD36 mRNA splice variants, a partial cDNA from HEL cells was isolated and characterized. This CD36 cDNA had a 309-base pair deletion following the region encoding the first putative transmembrane domain of CD36. The open reading frame of the deleted CD36 cDNA was retained and was predicted to yield a protein lacking 103 amino acid residues. The presence of this variant was confirmed in RNA pools from placental tissue by a reverse transcriptase-coupled polymerase chain reaction assay. Comparison of the HEL CD36 cDNA with the genomic sequence revealed that the mRNA represented by this variant CD36 cDNA was produced by a pre-mRNA splicing reaction that excluded exons 4 and 5. Transient expression of the variant CD36 cDNA in COS-1 cells showed that CD36 immunoreactive protein was expressed on the cell surface but lacked an antigenic epitope defined by amino acid residues 41-143. This cell surface glycoprotein (M(r) approximately 57,000) was of identical molecular weight as a CD36 isoform observed on the surface of HEL cells. The exclusion of exons during CD36 pre-mRNA processing appears to be conserved within one other CD36 gene family member, CLA-1.
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1106
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Tang Y, Taylor K, Sobieski D, Medved E, Lipsky R. Identification of a human CD36 isoform produced by exon skipping. Conservation of exon organization and pre-mRNA splicing patterns with a CD36 gene family member, CLA-1. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)37562-2] [Citation(s) in RCA: 28] [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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1107
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Xu K, Tang Y, Grifo JA, Rosenwaks Z, Cohen J. Primer extension preamplification for detection of multiple genetic loci from single human blastomeres. Hum Reprod 1993; 8:2206-10. [PMID: 8150925 DOI: 10.1093/oxfordjournals.humrep.a138004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A new technology called primer extension preamplification (PEP), which has been applied to single spermatozoa, increases the amount of polymerase chain reaction (PCR) templates by amplifying DNA of the whole genome. The current investigation was aimed at applying PEP to single human blastomeres. Two blastomeres with nuclei from arrested embryos were selected for this study. Using three different PEP protocols (experiments I, II and III), DNA from single blastomeres was amplified using 15-base oligonucleotide random primers. The efficiency of the procedure was determined by further amplifications of aliquots of the PEP products with two specific sequences. Three aliquots from each PEP product were used as PCR templates for the human X chromosome (X) or the exon 10 of the cystic fibrosis gene (CF). PCR amplified products were analysed by gel electrophoresis. In experiment I, when X primers were used, positive signals were detected in all 10 embryos (100%), 90.0% (18/20) of the blastomeres, and in 80.0% (96/120) of the replicates. When CF primers were amplified, all embryos (100%, 10/10), 90.9% (18/20) of the blastomeres and 78.3% (47/60) of the replicates were positive. In experiment II, efficiency was significantly reduced when total time for the procedure was minimized from 8 h to 5 h and 45 min. Although the time was further reduced to 4 h and 40 min in experiment III, the efficiency remained the same as in experiment I when the volume of PEP was reduced from 60 microliters (experiments I and II) to 40 microliters. One out of 132 control replicates (0.8%) was contaminated.(ABSTRACT TRUNCATED AT 250 WORDS)
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1108
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Taylor KT, Tang Y, Sobieski DA, Lipsky RH. Characterization of two alternatively spliced 5'-untranslated exons of the human CD36 gene in different cell types. Gene 1993; 133:205-12. [PMID: 7693552 DOI: 10.1016/0378-1119(93)90639-k] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We determined the nucleotide sequence of a 2.6-kb BamHI-EcoRI fragment from the 5'-end of the human gene encoding the cell adhesion receptor, CD36. This region contains the first coding exon, exon 3, as well as two non-coding exons, exons 2a and 2b, from the 5'-flanking region. Also present in the 5'-flanking region are two Alu repeats belonging to the Alu-Sa subfamily. When the determined genomic sequence was compared to a placental cDNA sequence [Oquendo et al., Cell 58 (1989) 95-101] and to a human erythroid leukemia (HEL) cell CD36 cDNA sequence (this report), we found that exons 2a and 2b do not occur within the same mRNA, suggesting that alternative splicing occurs within the 5'-untranslated region (UTR) of human CD36 pre-mRNA. These observations were confirmed by reverse transcriptase-coupled polymerase chain reaction (RT/PCR) assays using RNA from placental tissue, HEL cells and human platelets. Exon 2b encodes two alternative translation initiation codons which may render exon 2b-containing CD36 mRNA untranslatable. To test this hypothesis, we transfected COS-1 cells with an exon 2b-containing CD36 cDNA construct. Using anti-CD36 polyclonal antibody, we were able to detect an immunoreactive protein, consistent in size with the mature protein observed in transfected COS-1 cells. Therefore, exon 2b itself is insufficient to block translation of CD36 mRNA.
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1109
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Jin Y, Liu S, Li G, Tang Y, Chi Z. The crystal structure of the ternary complex of mung bean trypsin inhibitor with two porcine trypsin (PTRY-MBI-PTRY) at 2.8 Å resolution. Acta Crystallogr A 1993. [DOI: 10.1107/s0108767378096920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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1110
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Huang Q, Liu S, Tang Y, Jing S, Wang Y. Active center geometry and depurine mechanism studies of complexes of two ribosome-inactivating proteins. Acta Crystallogr A 1993. [DOI: 10.1107/s0108767378098207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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1111
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Tang Y, Lin CM, Chen TT, Kawauchi H, Dunham RA, Powers DA. Structure of the channel catfish (Ictalurus punctatus) growth hormone gene and its evolutionary implications. MOLECULAR MARINE BIOLOGY AND BIOTECHNOLOGY 1993; 2:198-206. [PMID: 8293072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A DNA fragment of 1.6 kilo base pairs (kb), encoding part of the channel catfish (Ictalurus punctatus) growth hormone (GH) gene, was generated by the polymerase chain reaction (PCR) using 2 degenerate synthetic oligonucleotides (30 and 33 mer) derived from the N- and C-terminal amino acid sequences of the catfish GH polypeptide as amplification primers and with catfish genomic DNA as a template. This DNA fragment was used as a probe for the isolation of a catfish GH gene from a genomic library constructed in a lambda phage cloning vector, lambda Dash II. Three positive clones were isolated, and their complete nucleotide sequences were determined. Nucleotide sequences from clones 1 and 3 were identical, whereas clone 2 had 2 base substitutions. The gene spans approximately 3 kb and is comprised of 5 exons and 4 introns. The initiation codon, the termination codon, and the canonical polyadenylation sequence were identified. The amino acid sequence deduced from the predicted coding region of the gene is in agreement with that of the native GH polypeptide sequence. A sequence (TATAAAA) matching the TATA box consensus sequence was located at nucleotide positions -30 to -23. Furthermore, 2 sequences corresponding to the mammalian Pit-1/GHF-1 binding sites (consensus sequence TT[AA]TATNCAT) were identified in the 5' flanking region starting at positions -113 and -134. Another sequence (GTACCAGTGA) conserved among the GH genes of the channel catfish and other known animal species was also identified at position -220. The biological functions of this sequence remain to be determined.(ABSTRACT TRUNCATED AT 250 WORDS)
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1112
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Tang Y, Norcia AM. Improved processing of the steady-state evoked potential. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1993; 88:323-34. [PMID: 7688287 DOI: 10.1016/0168-5597(93)90056-u] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two related procedures for estimating the parameters of steady-state evoked potentials (SSEPs) are introduced. The first procedure involves an initial stage of digital bandpass filtering followed by a Discrete Fourier Transform analysis. In the second method, a high resolution method based on parametric modelling is applied to the filtered data. The digital pre-filter consists of a non-phase shifting Chebychev bandpass filter. The parametric modelling method considers the evoked-response-plus-noise distribution to consist of a set of exponentially damped sinusoids. The frequency, amplitude, phase and damping factors of these components are estimated by calculating the mean of the forward and backward prediction filters and linear regression. We compared the signal-to-noise ratio (SNR) of the new procedures to the conventional Discrete Fourier Transform method for Monte Carlo simulations utilizing known sinusoids buried in white noise, known sinusoids buried in human EEG noise and for a sample of visual evoked potential data. Both of the new methods produce substantially more accurate and less variable estimates of test sinusoid amplitude. For VEP recording, the EEG background noise level is reduced by 5-6 dB over that obtained with the DFT. The new methods also provide approximately 5 dB better SNR than the DFT for detection of sinusoids based on the Rayleigh statistic. The parametric modelling approach is particularly suited for the analysis of very short data records including cycle-by-cycle analysis of the SSEP.
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1113
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Luo Y, Lai L, Xu X, Tang Y. Defining topological equivalences in protein structures by means of a dynamic programming algorithm. PROTEIN ENGINEERING 1993; 6:373-6. [PMID: 8332594 DOI: 10.1093/protein/6.4.373] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
An automatic algorithm for defining topological equivalences in protein structures is presented. The algorithm is based on a dynamic programming technique and self-consistent scoring method. We have used it to align pairs of similar protein structures of several protein families and to identify recurrent structural domains in aspartic proteinase 2APR. Its ability to find suboptimal paths permits a thorough comparison of proteins at each level in the hierarchy of the protein structure: secondary structure, super-secondary structure, domain and entire globular structure. The algorithm has been extended to the structure alignment of ribonucleic acid and can be extended to the structure alignment of any linear polymer.
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1114
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Wu SX, Tang Y. Molecular epidemiologic study of an outbreak of Salmonella typhimurium infection at a newborn nursery. Chin Med J (Engl) 1993; 106:423-7. [PMID: 8222893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Plasmid analysis, restriction endonuclease analysis, antimicrobial susceptibility testing, biotyping, phage typing and outer membrane protein electrophoresis were used to study an outbreak of Salmonella typhimurium infection at a newborn nursery. Seven out of the 12 neonates had positive blood cultures for S. typhimurium, and 2 of them died of severe sepsis. Thirty epidemic strains of S. typhimurium belonging to phage type 12 had the same plasmid profiles (98.0, 6.7 and 3.8 Kb) and identical restriction digest patterns (23.0, 20.4, 15.0, 9.6, 8.2, 7.4, 5.8, 4.3, 3.8, 2.0 and 1.8 Kb) which were different from those of the 2 non-epidemic strains. Laboratory data suggested that the source of the infection was the index patient's mother who had a slight diarrhea; the mode of transmission was most likely due to the transfer of organisms from infant to infant by the contaminated hands of nurses during milk feeding.
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1115
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Zou Z, Wang H, Chen D, Tang Y, Qiao X. [The applicability of a new stable fluorescence reagent CGE (N) for TLC measurements and spectrofluorimetry]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1993; 24:194-7. [PMID: 8244302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A new stable fluorescent reagent, CGE (N), was designed and synthesized in our laboratory. This paper presents the results of using it to detect a compound having aminogroup. Glycine as an example was derived by using CGE (N), the best condition of derivatisation reaction was pH8, T 50 +/- 1 degree C, and time 3-5 h. Spread agent was CHCl3: CH3OH:CH3COOC2H5: iceHAc (1:3:5:1). Rf of glycine-CGE (N) was 0.45, of which fluorescent spectrum Em was 356nm (at Ex = 277nm). The correlation coefficient between the fluorescent scanning area and quantity was over 0.99, the linear relation retained for 24 h, the detection limit 0.24 microgram, and the linear range 0.24-19.2 micrograms. The data revealed that stability, sensitivity and reproducibility were good. These indicate that CGE(N) is a fine fluorescent reagent for compounds having primary amino-group and this method is reliable.
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1116
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Tang Y, Reed SI. The Cdk-associated protein Cks1 functions both in G1 and G2 in Saccharomyces cerevisiae. Genes Dev 1993; 7:822-32. [PMID: 8491379 DOI: 10.1101/gad.7.5.822] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The CKS1 gene of Saccharomyces cerevisiae encodes a small essential protein shown to interact genetically and physically with the Cdc28 protein kinase. To investigate the specific functions of the CKS1 gene product, conditional temperature-sensitive mutant alleles were generated. The mutations were found to impair the ability of cells to undergo both the G1/S-phase and G2/M-phase transitions of the cell cycle, as well as the ability to bud. Mutants were not defective, however, in their ability to activate Cdc28 kinase as assayed in vitro on the substrate histone H1. It is likely, therefore, that Cks1 mediates a more specialized function of the Cdc28 kinase such as its ability to form specific multimeric complexes or to localize properly in cellular compartments.
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1117
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Killick-Kendrick R, Killick-Kendrick M, Tang Y, Sang DK, Johnson RN, Ngumbi PM. Phlebotomine sandflies of Kenya (Diptera: Psychodidae). I. The validity of Phlebotomus (Larroussius) elgonensis Ngoka, Madel and Mutinga. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1993; 87:207-15. [PMID: 8561529 DOI: 10.1080/00034983.1993.11812756] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Sandflies collected in Kitum cave on the Kenyan side of Mount Elgon were identified as Phlebotomus (Larroussius) elgonensis Ngoka, Madel and Mutinga, a species synonymized with P. (L.) aculeatus Lewis, Minter and Ashford, by D. J. Lewis. A comparison of the flies from Kitum cave with P. aculeatus from Lake Elmentaita, Kenya, shows marked differences in the lengths of: (a) the spermathecal ducts of the female; (b) the style, coxite, genital pump and aedeagus of the male; and (c) the palpal segments of both sexes. Other notable differences are in the shape of the base of the spermathecal ducts; the position of spines on, and the shape of, the tip of the aedeagus; and the appearance of the pharyngeal armatures of both sexes. Phlebotomus elgonensis is redescribed and it is concluded that it is sufficiently different from P. aculeatus to deserve recognition as a valid species.
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1118
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Tang Y, Hügin AW, Hartley JW, Fredrickson TN, Morse HC, Chattopadhyay SK. Effects of immunization with the p12 proteins of LP-BM5 defective and ecotropic viruses on development of MAIDS. Arch Virol 1993; 129:155-66. [PMID: 8385912 DOI: 10.1007/bf01316892] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Among murine leukemia viruses (MuLV) present in the LP-BM5 virus mixture, the agent etiologic for an acquired immunodeficiency syndrome (MAIDS) is replication defective, containing only a single open reading frame which includes all of gag. The Gag polyprotein encoded by the defective virus, termed BM5def, differs most in p12 from that of nonpathogenic ecotropic virus (BM5eco). As one approach to examining the role of p12 in disease, the ecotropic and defective virus forms of the protein, synthesized in bacteria, were used to immunize three strains of mice differing in their sensitivity to MAIDS. In each strain, both proteins elicited substantial antibody responses that were cross-reactive with either p12 and recognized the proteins as part of intact viral Gag polyproteins. Immunization with either p12 before infection with LP-BM5 viruses had no effect on the sensitivity or resistance of mice to MAIDS or on the extent of helper virus spread. The variant p12 of BM5def, when presented on its own, is thus not a crucial antigenic determinant of disease. Alternative mechanisms by which BM5def may contribute to MAIDS are discussed.
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1119
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Fredrickson TN, Tang Y, Chattopadhyay SK, Morse HC, Hartley JW. Retrovirus-induced lymphoproliferation as a model for developing diagnostic criteria for malignant lymphoma in mice. Toxicol Pathol 1993; 21:219-28. [PMID: 8210944 DOI: 10.1177/019262339302100214] [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: 01/29/2023]
Abstract
Several methods for evaluating lymphoproliferative lesions in mice were compared. The model systems included spontaneous lymphomas arising in CWD mice and NFS mice congenic for ecotropic murine leukemia virus (MuLV) induction loci and a series of transplants in mice with severe combined immunodeficiency disease mutation of cells derived from mice infected with LP-BM5 MuLV. Primary lymphomas and donor tissues and transplants were examined using histopathology, flow cytometry, and Southern blot analysis of DNA for rearrangements of immunoglobulin and T-cell receptor genes and for viral integrations. The use of flow cytometric analysis, to establish cell lineage and define population size, and DNA analysis, for cell lineage and clonality determination, allowed the identification of malignant lymphoproliferations. Histologic evaluation did not define clonal populations of particular lineage but did provide other indications of malignancy such as invasiveness and presence of a dominant morphologic cell type. Thus, the precision of diagnosis of mouse lymphomas can be considerably enhanced by augmenting histopathologic examination with antigenic and molecular characterizations that can define malignant populations.
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1120
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Tang Y, Wang JM, Huang CH. Syncope in nasopharyngeal carcinoma: report of three cases and review of the literature. CHANGGENG YI XUE ZA ZHI 1993; 16:59-65. [PMID: 8490777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Syncope is an uncommon symptom in patients with nasopharyngeal carcinoma (NPC). Here we report three cases of NPC with syncope. One had bilateral neck masses, invasion of the skull base, and lower cranial nerve palsies. The other two presented with neck mass only. Repeated episodes of syncope were initially controlled by intravenous atropine followed by radiotherapy and/or chemotherapy. The large primary tumor with parapharyngeal space extension and neck lymph node involvement, the invasion of the skull base and the presence of lower cranial nerve palsies are the three important risk factors for developing syncope. This is probably mainly due to the mass compression of the carotid sinus or the glossopharyngeal nerve invasion. We therefore classified these 3 cases into carotid sinus syncope type, glossopharyngeal neuralgia type and parapharyngeal space lesions type. The prognosis is poor for cases of NPC with syncope because most patients have advanced or recurrent disease, however, atropine and radiotherapy with or without chemotherapy are effective for the symptomatic treatment of syncope from locally advanced NPC.
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1121
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Ni Z, Li S, Liu Y, Tang Y, Pang D. [Induction of micronucleus by organophosphorus pesticides both in vivo and in vitro]. HUA XI YI KE DA XUE XUE BAO = JOURNAL OF WEST CHINA UNIVERSITY OF MEDICAL SCIENCES = HUAXI YIKE DAXUE XUEBAO 1993; 24:82-6. [PMID: 8340099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
A total of 22 organophosphorus pesticides (OPPs), including 8 ethyl-, 9 methyl-, and 5 other OPPs, were tested for mutagenicity in micronucleus assay system both in 615 mouse marrow cells in vivo with multi-intraperitoneal administrations and in cultured Chinese hamster lung (CHL) cells in vitro; and structure-mutagenicity relationship of OPPs was analyzed. Among the OPPs tested in vivo, 5 ethyl-(diazinon, chlorpyrifos, disulfoton, ethion, and parathion), and only 1 methyl-(dimethoate) were found mutagenic, while the other OPPs were negative. Six ethyl- (azinphos ethyl, chlorpyrifos, ethion, parathion, phosaione, and quinaphos), 8 methyl- (azinophos methyl, chlorpyrifos methyl, dichlorvos, dimethoate, fenitrothion, malathion, parathion methyl, and trimethyl phosphate), and 2 other OPPs (EII and MIA), however, induced micronucleus in CHL cells in vitro. The results indicated that most of the ethyl-OPPs tested showed the ability to induce micronucleus both in vivo and in vitro, and that most of the methyl-OPPs were positive only in vitro. The mechanism for the adversity of mutagenic activity in micronucleus assay in vivo and in vitro produced by different kinds of OPPs was also discussed.
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1122
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Huang Q, Liu S, Tang Y. Refined 1.6 A resolution crystal structure of the complex formed between porcine beta-trypsin and MCTI-A, a trypsin inhibitor of the squash family. Detailed comparison with bovine beta-trypsin and its complex. J Mol Biol 1993; 229:1022-36. [PMID: 8445634 DOI: 10.1006/jmbi.1993.1102] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The crystal structure of the complex formed by porcine beta-trypsin with the MCTI-A inhibitor (Momordica charantia, Linn. Cucurbitaceae) has been determined at 1.6 A resolution using the molecular replacement method. The sequence of MCTI-A was determined by recognizing the electron density, and shows that MCTI-A is a member of the squash family of trypsin inhibitors. We report the first high-resolution structure of porcine beta-trypsin. Detailed comparisons have been made on the overall structure, solvent structure and active-site geometries between this complex and bovine beta-trypsin and its complexes. On the basis of our results, we discuss the interaction patterns between inhibitor and trypsin. Unlike other complex structures formed by bovine trypsin with inhibitors, no out-of-plane distortion around the inhibitor's scissible peptide was observed. The role of the trypsin catalytic triad is also discussed on the basis of this structure.
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1123
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Cui Y, Withers DE, Rae CF, Norrie CJ, Tang Y, Sinclair BD, Sibbett W, Dunn MH. Widely tunable all-solid-state optical parametric oscillator for the visible and near infrared. OPTICS LETTERS 1993; 18:122-124. [PMID: 19802058 DOI: 10.1364/ol.18.000122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An all-solid-state optical parametric oscillator (OPO) has been developed in which the signal and idler waves can be tuned over the ranges 455-665 and 760-1620 nm, respectively, with the potential for covering the entire range 420-2300 nm. The OPO uses a critical type I phase-matching geometry in lithium triborate and is pumped at 355 nm by frequency-tripled radiation from a diode-laser-pumped Nd:YAG laser. Oscillation thresholds (minimum 0.3 mJ), pump depletions (>35%), and linewidths of the OPO are reported.
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1124
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Chen YT, Tang Y. [Experimental and clinical study on cryptosporidiasis. III. Ultrastructural observation on Cryptosporidium in immunosuppressed mice]. ZHONGGUO JI SHENG CHONG XUE YU JI SHENG CHONG BING ZA ZHI = CHINESE JOURNAL OF PARASITOLOGY & PARASITIC DISEASES 1993; 11:291-293. [PMID: 8082271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The ultrastructure of Cryptosporidium parvum, which parasitized on the surface of the intestine of the immunosuppressed mice, was studied by transmission electron microscopy. The parasite was enveloped by the parasitophorous vacuole developed from the host epithelial cell. An electron dense band was found at the attachment site between the Cryptosporidium and the host cell. At the attachment site, the cytoplasma membrane of Cryptosporidium appeared in the form of many membranous folds, and contacted closely with the plasma membrane of the epithelial cell. Rhoptry-like structure and small electron dense granules were found in the merozoite, but their effects on the development of Cryptosporidium are still unknown (Figs. 1-5).
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Tang Y. No alpha-lactalbumin-like activity detected in a low molecular mass protein fraction of rat epididymal extract. Reprod Fertil Dev 1993; 5:229-37. [PMID: 8265806 DOI: 10.1071/rd9930229] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The same low M(r) protein fraction of epididymal luminal fluid as that studied previously by Hamilton in 1981 was assayed for alpha-lactalbumin (alpha-lac) activity with bovine milk galactosyltransferase (GalTase) as the enzyme source and bovine serum albumin (BSA) to make the total protein concentrations of all the samples in each assay constant. No alpha-lac activity could be detected in this fraction. When glucose was used as an acceptor, radioactivity passing through the ion exchange column used to retain the remaining UDP-galactose did increase with the amount of the proteins of the low M(r) fraction, but this increase was observed not only for samples with an acceptor but also for samples without. The increased radioactive product co-migrated in high-voltage electrophoresis with galactose, not lactose. When GlcNAc was used as an acceptor, the situation was the same, and the increased radioactive product co-migrated with galactose, not LacNAc. No inhibition of bovine milk GalTase activity by the low M(r) proteins was observed. Addition of protein, either BSA or the low M(r) fraction of epididymal luminal fluid, to assay medium that contained no proteins other than GalTase enhanced the GalTase activity both in forming lactose in the presence of glucose and also LacNAc in the presence of GlcNAc. It appears that the earlier reports of alpha-lac-like activity in epididymal fluids and extracts may have been due to the presence of enzymes liberating free galactose from UDP-galactose and/or a stimulatory non-specific effect of the protein in the solutions on the lactose synthesis activity of the GalTase.
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