Human immunodeficiency virus type 1 infection of the heart in three infants with acquired immunodeficiency syndrome and sudden death.
Explore the source record for details and available documents.
Acquired Immunodeficiency Syndrome↗
Biomedical subjects
X L Li
Publications and source records attributed to X L Li.
Expression of Aureobasidium pullulans xynA in, and secretion of the xylanase from, Saccharomyces cerevisiae.
A previous report dealt with the cloning in Escherichia coli and sequencing of both the cDNA and genomic DNA encoding a highly active xylanase (XynA) of Aureobasidium pullulans (X.-L. Li and L. G. Ljungdahl, Appl. Environ. Microbiol. 60:3160-3166, 1994). Now we show that the gene was expressed in Saccharomyces cerevisiae under the GAL1 promoter in pYES2 and that its product was secreted into the culture medium. S. cerevisiae clone pCE4 with the whole open reading frame of xynA, including the part coding for the signal peptide, had xylanase activity levels of 6.7 U ml-1 in the cell-associated fraction and 26.2 U ml-1 in the culture medium 4 h after galactose induction. Two protein bands with sizes of 25 and 27 kDa and N-terminal amino acid sequences identical to that of APX-II accounted for 82% of the total proteins in the culture medium of pCE4. These proteins were recognized by anti-APX-II antibody. The results suggest that the XynA signal peptide supported the posttranslational processing of xynA product and the efficient secretion of the active xylanase from S. cerevisiae. Clones pCE3 and pGE3 with inserts of cDNA and genomic DNA, respectively, containing only the mature enzyme region attached by a Met codon had low levels of xylanase activity in the cell-associated fractions (1.6 U ml-1) but no activity in the culture media. No xylanase activity was detected in clone pGE4, which was the same as pCE4, except that pGE4 had a 59-bp intron in the signal peptide region. A comparison of the A. pullulans and S. cerevisiae signal peptides demonstrated that the XynA signal peptide was at least three times more efficient than those of S. cerevisiae invertase or mating alpha-factor pheromone in secreting the heterologous xylanase from S. cerevisiae cells.
Amino Acid Sequence↗
[Separation and identification of the flavonoids from Buddleia officinalis Maxim].
The flowers of Buddleia officinalis Maxim have been used to cure eye inflammation in China. Eight flavonoid compounds were isolated from them. Their structures were characterized as acacetin (1), apigenin (2), luteolin (3), neobudofficide (4), linarin (acaciin 5), luteolin-7-O-rutinoside (6), luteolin-7-O-glucoside (7) and cosmosiin (8), on the basis of chemical and spectral evidences. The new compound 4 was identified as 5,7-dihydroxy-4'-O-methoxyflavone-7-O-alpha-L-rhamnopyranosyl (1-->2)-[alpha-L-rhamnopyranosyl (1-->6)]-beta-D-glucopyranoside and named neobudofficide. All the compounds were isolated from B. officinalis for the first time, except linarin and acacetin.
Ellagic Acid↗
Quenching: inhibition of development and expression of amygdala kindled seizures with low frequency stimulation.
Using low frequency (quenching) stimulation parameters (1 Hz for 15 min), similar to those that induce long-term depression (LTD) in vitro, we attempted to alter amygdala kindling in vivo in rats. Quenching completely blocked the development and progression of after-discharges and seizures in seven of eight animals. In fully kindled animals, once-daily quenching stimulation for one week (without concurrent kindling) suppressed the seizures when kindling stimulation was resumed. These effects of quenching probably resulted from the marked and long-lasting increases in the afterdischarge and seizure thresholds that were observed in these animals. These data indicate that quenching with low frequency electrical stimulation (which does not disrupt ongoing behavior) can have profound and long-lasting effects on seizure development, expression, and thresholds. The ultimate clinical applicability of low frequency stimulation in the treatment of seizures and related neuropsychiatric disorders remains to be explored.
Amygdala↗
A cyclophilin from the polycentric anaerobic rumen fungus Orpinomyces sp. strain PC-2 is highly homologous to vertebrate cyclophilin B.
A cyclophilin (CyP) purified to homogeneity from the polycentric anaerobic rumen fungus Orpinomyces sp. strain PC-2 had a molecular mass of 20.5 kDa and a pI of 8.1. The protein catalyzed the isomerization of the prolyl peptide bond of N-succinyl-Ala-Ala-(cis,trans)-Pro-Phe p-nitroanilide with a kcat/Km value of 9.3 x 10(6) M-1.s-1 at 10 degrees C and pH 7.8. Cyclosporin A strongly inhibited this peptidylprolyl cis-trans isomerase activity with an IC50 of 19.6 nM. The sequence of the first 30 N-terminal amino acids of this CyP had high homology with the N-terminal sequences of other eukaryotic CyPs. By use of a DNA hybridization probe amplified by PCR with degenerate oligonucleotide primers designed based on the amino acid sequences of the N terminus of this CyP and highly conserved internal regions of other CyPs, a full-length cDNA clone was isolated. It possessed an open reading frame encoding a polypeptide of 203 amino acids with a calculated molecular weight of 21,969, containing a putative hydrophobic signal peptide sequence of 22 amino acids preceding the N terminus of the mature enzyme and a C-terminal sequence, Lys-Ala-Glu-Leu, characteristic of an endoplasmic reticulum retention signal. The Orpinomyces PC-2 CyP is a typical type B CyP. The amino acid sequence of the Orpinomyces CyP exhibits striking degrees of identity with the corresponding human (70%), bovine (69%), mouse (68%), chicken (66%), maize (61%), and yeast (54%) proteins. Phylogenetic analysis based on the CyP sequences indicated that the evolutionary origin of the Orpinomyces CyP was closely related with CyPs of animals.
Amino Acid Isomerases↗
Green-tea consumption and risk of stomach cancer: a population-based case-control study in Shanghai, China.
The effect of drinking Chinese green tea on the risk of stomach cancer was evaluated in a population-based case-control study conducted in Shanghai, China, from October 1991 to December 1993. Eligible cases were incident cases of primary stomach cancer diagnosed during the study period among residents of Hongkou district and Nanhui county aged under 80 years. Controls were selected from the same street or commune where the case resided and were matched to the cases on age (within three years) and gender. A total of 711 cases and 711 matched controls, more than 90 percent of the eligible subjects, completed the interview. Information was obtained on the types of tea used, age when habitual tea drinking started, frequency of new batches of tea leaves used per day, number of cups brewed from each batch, total duration of drinking for each batch, strength and temperature of the tea consumed. Statistical analysis was based on modelling through conditional logistic regression. After adjusting for age, gender, place of residence, education, birthplace, alcohol consumption, and cigarette smoking, the odds ratio (OR) comparing drinkers of green tea with nondrinkers was 0.71 (95 percent confidence interval = 0.54-0.93). The adjusted OR decreased with increasing number of new batches of the green tea consumed each day (P value trend = 0.006). With the largest series of stomach cancer cases to date, this study found green-tea consumption associated with lower risk of stomach cancer. Among drinkers of green tea, the risk of stomach cancer did not depend on the age when habitual green-tea drinking started. Green tea may disrupt gastric carcinogenesis at both the intermediate and the late stages.
Adult↗
Comparison of a rapid nonisotopic polymerase chain reaction assay with four commonly used methods for the early diagnosis of human immunodeficiency virus type 1 infection in neonates and children.
To initiate antiretroviral therapy and prophylaxis for Pneumocystis carinii pneumonia, it is important to identify human immunodeficiency virus (HIV-1)-infected infants as soon after birth as possible. This study was undertaken to evaluate a novel 5-hour nonisotopic (NI) polymerase chain reaction (PCR) assay (Amplicor PCR; Roche Molecular Systems) and four other commonly used HIV-1 diagnostic tests including culture, oligonucleotide hybridization PCR, p24 antigen and immune complex-dissociated (ICD) p24 antigen tests and to determine the optimal age at which to perform these tests for the early and rapid diagnosis of HIV-1 in infants and children. We prospectively evaluated 225 infants and children, including 114 neonates, for HIV-1 infection. HIV-1 infection was defined as 2 positive HIV cultures. Of the 225 infants and children, 57 were infected, 138 were uninfected and 30 were of unknown (Centers for Disease Control and Prevention Classification P0) status. The sensitivity of NI PCR was 60% in cord blood, 40% at 0 to 2 days, 67 to 80% in the neonate (3 to 30 days) and 95 to 100% after 1 month of age. NI PCR was as sensitive as oligonucleotide hybridization PCR, culture, p24 antigen and ICD p24 antigen in the first 2 months of life and was more sensitive than p24 antigen or ICD p24 antigen thereafter. Specificity was 94% for cord blood and 99 to 100% for all age groups. The majority of HIV-1-infected newborns can be identified with NI PCR if testing is performed at birth and again between the third and fourth weeks of life. For older infants and children 2 NI PCR tests can correctly diagnose 98.5% of infected and uninfected infants and children. NI PCR of umbilical cord blood might also be useful as an initial screening test to identify infants who may be infected with HIV-1.
AIDS Serodiagnosis↗
[The cardiovascular reactions mediated by TPA and tamoxifen in spinal cord of conscious rats].
Intrathecal administration (ith) of phorbol 12-myristate (TPA), an activator of protein kinase C, (31.24, 26.5, 125 and 250 ng/10 micrograms) to conscious rats produced a marked dose-dependent pressor effect without significant change in heart rate (HR). Intrathecal administration of tamoxifen (3.125, 6.5 and 100 micrograms/10 microliters), one of the inhibitors of protein kinase C, produced a marked dose-dependent hypotensive effect. Intrathecal injection of exogenous DBcAMP (12.5, 25, 50 and 100 micrograms/10 microliters) also increased the mean arterial blood pressure (mABP) and markedly lowered HR. It was further observed that, based on the effect of DBcAMP (25 micrograms/10 microliters), the pressor effect of four doses of TPA can be augmented. The results indicate that TPA in spinal cord may exert hypertensive effect via activation of PKC and tamoxifen may exert a hypotensive effect via inhibition of PKC. In addition, the pressor effect of TPA could be augmented by preadministration of DBcAMP.
Animals↗
Biomass degrading enzymes from anaerobic rumen fungi.
Obligately anaerobic fungi are part of the natural microflora of the alimentary tract of many herbivorous mammals. They produce a complete set of polysaccharide hydrolytic enzymes which efficiently degrade plant cell-walls. This article summarizes the present work on biomass degrading enzymes with special emphasis on their cellulases, xylanases, and esterases from both monocentric and polycentric anaerobic fungi. The possibility of the cellulosome or xylanosome-like high molecular mass complexes in the fungi are also discussed.
Anaerobiosis↗
[Expression of exogenous porcine transforming growth factor beta-1 gene in ES cells and its effect on their differentiation in vitro].
A TGF-beta 1 gene expression plasmid was constructed by inserting the porcine 1.7 Kb TGF-beta 1 cDNA into BamHI site of retrovirus vector Dol. The plasmid DNA was introduced into mouse embryonic stem cells (ES-5 line) by calcium phosphate mediated transfection, and transfected ES-5 cells were then selected by stepwise increase in G418 concentration. Finally, we obtained 21 clones that could be stably grown in culture medium with G418 at 500 micrograms/ml and were designated as ES-T cells. Dot blot and Northern analysis of total RNA and polyA+ RNA extracted from those ES-T cells were shown in FIg. 2 and 3, demonstrating that 6 clones could express exogenous porcine TGF-beta 1 mRNA. The stronger hybridized signal in two clones (ES-T6 and ES-T 16) of them were further proved by southern hybridization of genomic DNA from these ES-T cells with 1.7 Kb TGF-beta 1 cDNA probe (Fig. 4). The product of TGF-beta 1 gene overexpression in ES-T 6 cells was shown in Fig. 5 and 6 by SE-LISA for TGF-beta 1 immunoreactivity to TGF-beta 1 antibodies and biological assay for CCL/64 cell growth inhibition, respectively. With respect to some biological characteristics, ES-T 6 cells, like their parent ES-5 cells, retained their pluripotent properties and positive SSEA-1 antigen (Plate I, Fig. 1). ES-T6 cells were expanded and used for studies of in vitro differentiation. Both of ES-T 6 cells and control ES-5 cells could form a lot of simple aggregates and differentiate into embryoid bodies by hanging drop culture for 3 days in the presence of retinoic acid (RA) at 10(-9) mol/L. Then individual embryoid bodies were plated on gelatinized tissue culture wells. On the third day of further culture without RA, a large amounts of epithelial-like and round cells occurred around the embryoid bodies formed either from ES-T 6 cells or ES-5 cells (Plate I, Fig. 4). However, with further culture of embryoid bodies, only the cells differentiated from ES-T6 embryoid bodies could arrange themselves and differentiate into a lot of radially arranged tubular structures (Plate II, Fig. 5). The frequency of tubular structures present in ES-T6 embryoid bodies were about 95.5%, but in ES-5 group there was only about 17.8% cases giving less defined tubular structures (Plate III, Fig. 8).(ABSTRACT TRUNCATED AT 400 WORDS)
Animals↗
[Care of rheumatoid arthritis treated with bee acupuncture].
Explore the source record for details and available documents.
Acupuncture Therapy↗
Sequence-ion enhancement of peptides digested with proteinase K.
Proteinase K has been employed to proteolyze peptides before their mass spectrometric analysis. This combination of the two methods yields abundant sequence ions in the mass spectrum, thus leading to an easy prediction of the primary structure of the peptide. It was found that both the variety of available sequence ions and also their abundances are increased strongly after proteinase K digestion, when compared with the normal mass spectrum. The shortcoming of little fragmentation encountered using conventional mass spectrometric ionization methods can mostly be overcome. The H'n and Y"m ions produced from proteolysis provided a double check of the peptide sequence.
Amino Acid Sequence↗
Pattern recognition analysis to the variation of nasal-pharynx cancer patients' trace element levels in samples of hair, whole blood, and tissue.
Pattern recognition has been used in this paper to analyze trace element levels in patients diagnosed with nasal-pharynx cancer (NPC) and in healthy control subjects. Trace elements such as Zn, Cu, Fe, Mn, and Mg have been tested in samples of hair and whole blood. Through Mahalanobis Distance Decision analysis, we have achieved good classification effects in whole blood samples: Efficiency for distinguishing patients in 96% and that of healthy controls is 90%. Classification hair samples is inferior to whole blood: Decision accuracy for patients is 58% and healthy controls is 90%. These results are also shown in a nonlinear mapping figure. At the same time, we have also determined 5 trace element levels in 16 other cancer patients' nonneoplastic and cancerous tissue, with no significant difference between them: Decision accuracy of cancerous tissue is 63%, and in nonneoplastic tissue is 50%, hence, we cannot identify them. It can be inferred that there is no idiosyncratic change of trace elements in cancer patients' neoplastic tissue, the change of a cancerous person may occur in the whole body.
Adult↗
Cloning, sequencing, and regulation of a xylanase gene from the fungus Aureobasidium pullulans Y-2311-1.
Explore the source record for details and available documents.
Amino Acid Sequence↗
Cloning, sequencing, and regulation of a xylanase gene from the fungus Aureobasidium pullulans Y-2311-1.
Aureobasidium pullulans Y-2311-1 growing on xylan secretes four major xylanases with different masses and isoelectric points. Two of these enzymes, named APX-I and APX-II, have been purified previously. Their N-terminal amino acid sequences are identical except that APX-I has Asp and APX-II has Asn at position 7. An 83-bp DNA region was amplified by PCR and used as a probe for the xylanase gene cloning. The longest cDNA (xynA) obtained by cDNA cloning and PCR amplification consisted of 895 bp. A. pullulans xynA had an open reading frame encoding a polypeptide of 221 amino acids with a calculated mass of 23,531 Da and contained a putative 34-amino-acid signal peptide in front of the amino terminus of the mature enzyme. Strong homology was found between the deduced amino acid sequence of XynA and some xylanases from bacterial and fungal sources. It is suggested that A. pullulans XynA belongs to the family G glycanases. Northern (RNA blot) analysis revealed that only one transcript of 900 bases was present in cultures grown in medium containing D-xylose or oat spelt xylan. Transcription was completely repressed in the presence of glucose in the medium. Southern blot analysis indicated that A. pullulans xynA was present as a single copy in the genome. Comparison between the genomic and cDNA sequences revealed that one intron of 59 bp was present in the coding region. The data presented suggest that the highly active xylanases, APX-I and APX-II, secreted by A. pullulans are encoded by the same gene.
Amino Acid Sequence↗
[Experimental study of the 50% damage threshold of Nd:YAG laser on IOL].
The 50% damage threshold (DT50) of Nd:YAG laser was determined for IOLs of PMMA (lathed or molded), silicone and glass. The laser resistances in increasing order were silicone 79.22 gW/cm2, glass 100.82 gW/cm2, lathed PMMA 115.23 gW/cm2 and molded PMMA 142.49 gW/cm2. The authors recommended that only dosages below the DT50 be used in posterior capsulotomy to minimize the risk of IOL damage. The various laser damage patterns on IOL were studied by scanning electron microscopy.
Glass↗
[Chemical components of Trachelospelmun jasminoides (Lindl.) Lem. var. heterophyllum Tsiang].
Five kind of crystal products were isolated from the methyl alcohol extract of Trachelospelmum jasminoides var. heterophyllum. By using chemical analysis and spectrogrophical identification, four of these five products were proved to be arctigenin-4'-beta-gentiobiosid,tracheloside and two kinds of optical isomer of beta-tracheloside. The last two were found in this genus for the first time.
4-Butyrolactone↗
Studies on mechanisms and blockade of carcinogenic action of female sex hormones.
Tumours of mice are induced by administration of Inj. Hydroxyprogesteroni Caproatis Co. (EP) in a practical subthreshold dose of carcinogenesis or 2.5-5 times the human contraceptive dose (simply referred to as 2.5- to 5-fold dose) combined with whole-body 0.5 Gy gamma-ray irradiation. Malignant transformation of Syrian golden hamster embryo (SHE) cells is also induced by 5-fold dose of EP combined with 0.3 Gy gamma-ray irradiation in vitro, thereby indicating that synergistic carcinogenesis can be obtained by combined use of physical and chemical carcinogens. The mechanisms of synergistic carcinogenesis have been further explained by cytogenetics, damage extent of the target cell DNA and production of free radicals. The Chinese traditional medicine with antioxidating effect (Sulekang Capsule, SC), food additive--butylated hydroxyanisole (BHA) and green tea can effectively inhibit the carcinogenic effect of EP or EP combined with gamma rays in mice. They all have marked ability to scavenge or remove the free radicals and thereby reduce the DNA damage.
17 alpha-Hydroxyprogesterone Caproate↗