Recovery of binocular responses by cortical neurons after early monocular lesions.
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Animals↗
Biomedical subjects
B Zhang
Publications and source records attributed to B Zhang.
Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions.
Plants synthesize the osmoprotectant glycine betaine (GB) via choline-->betaine aldehyde-->glycine betaine[1]. Two enzymes are involved in the pathway, choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). A full length CMO cDNA (1,643bp) was cloned from Amaranthus tricolor. The open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with CMOs in Spinacia oleracea L. and Beta vulgaris L. DNA gel blot analysis indicated the presence of one copy of CMO gene in the A. tricolor genome. The expressions of CMO and BADH proteins in A.tricolor leaves significantly increased under salinization, drought and heat stress (42 degrees C), as determined by immunoblot analysis, but did not respond to cold stress (4 degrees C), or exogenous ABA application. The increase of GB content in leaves was parallel to CMO and BADH contents.
Aldehyde Oxidoreductases↗
A highly efficient and consistent method for harvesting large volumes of high-titre lentiviral vectors.
Lentiviral vectors pseudotyped with vesicular stomatitis virus glycoprotein (VSV-G) are emerging as the vectors of choice for in vitro and in vivo gene therapy studies. However, the current method for harvesting lentivectors relies upon ultracentrifugation at 50,000 g for 2 h. At this ultra-high speed, rotors currently in use generally have small volume capacity. Therefore, preparations of large volumes of high-titre vectors are time-consuming and laborious to perform. In the present study, viral vector supernatant harvests from vector-producing cells (VPCs) were pre-treated with various amounts of poly-L-lysine (PLL) and concentrated by low speed centrifugation. Optimal conditions were established when 0.005% of PLL (w/v) was added to vector supernatant harvests, followed by incubation for 30 min and centrifugation at 10,000 g for 2 h at 4 degrees C. Direct comparison with ultracentrifugation demonstrated that the new method consistently produced larger volumes (6 ml) of high-titre viral vector at 1 x 10(8) transduction unit (TU)/ml (from about 3,000 ml of supernatant) in one round of concentration. Electron microscopic analysis showed that PLL/viral vector formed complexes, which probably facilitated easy precipitation at low-speed concentration (10,000 g), a speed which does not usually precipitate viral particles efficiently. Transfection of several cell lines in vitro and transduction in vivo in the liver with the lentivector/PLL complexes demonstrated efficient gene transfer without any significant signs of toxicity. These results suggest that the new method provides a convenient means for harvesting large volumes of high-titre lentivectors, facilitate gene therapy experiments in large animal or human gene therapy trials, in which large amounts of lentiviral vectors are a prerequisite.
Animals↗
Selection of a high-biomass, chromium-rich yeast strain and optimization of cultivation conditions.
Saccharomyces cerevisiae LZ-53 was selected from 240 primary yeast strains from different genera and species, whose chromium (Cr) resistance and biomass were higher than others were. The highest biomass and Cr content of the strain was obtained in 30 h at 28 degrees C and 200 rpm, when 20 ml of the culture in 250-ml shake flasks was grown in wort containing 1200 microg/ml Cr. The initial pH was adjusted to 6.0. The optimal inoculum volume was 10% (v/v). The Cr content of the cells was determined by neutron activation analysis. Under the optimized cultivation conditions, the Cr content reached 3248 microg/g.
Biomass↗
Public health impact of adverse bone effects of oral corticosteroids.
AIMS: The objective of this study was to estimate the number of fractures attributed to oral corticosteroid use. METHODS: Information was obtained from the General Practice Research Database which contains medical records of general practitioners in the UK. The total number of corticosteroid-related fractures during a course of treatment was estimated using the formula for attributable risk among the exposed. RESULTS: A total of 244 235 patients was prescribed an oral corticosteroid. The rate of hip fractures increased exponentially with age in both males and females. The excess number of hip fracture cases among females aged 85 years or older using 7.5 mg prednisolone per day or more was 1.4 cases per 100 patients per year. About 47% of all hip and 72% of all vertebral fractures that occurred can be attributed to oral corticosteroid use. Among 10 000 female users of higher doses, 99.7 nonvertebral, 31.6 hip and 45.8 vertebral fractures can be attributed to use of oral corticosteroids. CONCLUSIONS: The targeting of high-risk patients will be important for implementing preventative strategies in a cost-effective manner.
Administration, Oral↗
Chronic hypoosmolality induces a selective decrease in magnocellular neurone soma and nuclear size in the rat hypothalamic supraoptic nucleus.
The magnocellular neurones of the hypothalamo-neurohypophysial system (HNS) play a vital role in the maintenance of body homeostasis by regulating oxytocin (OT) and vasopressin (VP) secretion from the posterior pituitary. During hyperosmolality, OT and VP mRNA levels are known to increase by approximately two-fold, whereas during chronic hypoosmolality, OT and VP mRNA levels decrease to approximately 10-20% of basal levels. In these studies, we evaluated changes in cell size associated with these physiological conditions. Cell and nuclear sizes of neurones in the supraoptic nucleus (SON), the nucleus of the lateral olfactory tract (LOT) and the medial habenular nucleus (MHB) were measured from neurones identified by in situ hybridization histochemistry for beta(III)-tubulin mRNA, and measurements were made from OT and AVP magnocellular neurones in the SON after phenotypic identification by immunohistochemistry. Under hypoosmolar conditions, the cell and nuclear sizes of OT and VP magnocellular neurones decreased to approximately 60% of basal values, whereas cell and nuclear sizes of OT and VP neurones in hyperosmolar rats increased to approximately 170% of basal values. In contrast, neither hyperosmolality, nor hypoosmolality significantly affected cell and nuclear sizes in the LOT and MHB. These results confirm previous studies that showed that magnocellular neurones increase cell size in response to hyperosmolar conditions and, for the first time, demonstrate a marked decrease in cell size in the SON in response to chronic hypoosmolar conditions. These dramatic changes in cell and nuclear size directly parallel changes in OT and VP gene expression in the magnocellular neurones of the SON and, consequently, are consistent with the pronounced bidirectional changes in gene expression and cellular activity found during these osmotic perturbations. Our results therefore support the concept of global alterations in the synthetic activity of magnocellular OT and AVP neurones in response to extracellular osmolality.
Animals↗
Do we measure the right end points? A systematic review of primary outcomes in recent neonatal randomized clinical trials.
OBJECTIVES: We performed a systematic review of primary outcomes in recently published neonatal randomized clinical trials to determine what end points are chosen for the evaluation of therapies in newborn infants. METHODS: MEDLINE was searched in May 1998 for neonatal RCTs that had been published since 1993 in the British Medical Journal, The Journal of Pediatrics, Lancet, The New England Journal of Medicine, and Pediatrics. The primary outcome was identified wherever possible. Continuous measures were distinguished from discrete outcome events. The latter were classified as "long-term" if they were ascertained at least 6 months after birth. The hypothesized relative risk reduction for primary outcome event rates was calculated, where possible. RESULTS: Of 119 eligible reports, 91 had an identifiable primary outcome that was a continuous measure in 46 trials and a discrete event in 45 trials. The median relative risk reduction was 50% for 28 of 40 short-term trials and 40% for 3 of 5 long-term trials. CONCLUSIONS: Most authors of recently published neonatal RCTs in 5 high-profile journals either failed to specify a primary end point or chose a continuous outcome measure. Trials with a discrete primary outcome were often short-term and designed to detect large risk reductions. Therefore modest but important treatment effects were likely missed by many of these trials.
Data Interpretation, Statistical↗
Human beta-defensin 2 is up-regulated during re-epithelialization of the cornea.
PURPOSE: Human beta-defensins 1 and 2 (hBD-1, -2) are antimicrobial peptides found in several epithelia including corneal epithelium. Breach of the epithelium leaves the cornea vulnerable to infection so we sought to determine if there is an increase in defensin expression after injury. METHODS: The epithelium from human cadaver corneas was collected by scraping (original samples). The corneas were then placed into organ culture to permit regeneration of the epithelium. Samples of re-grown epithelium were collected when healing was partially and 100% complete as determined by fluorescein staining. Total RNA was extracted from original and re-grown samples and used in RT-PCR reactions using primers specific for hBD-1 and hBD-2 and the constitutively expressed gene glyceraldehyde-3-phosphate dehydrogenase. Immunoblotting was performed to detect defensin peptide in original and re-grown samples. RESULTS: hBD-1 mRNA was detected in all original epithelial tissue samples (n = 10) examined suggesting that it is constitutively expressed. hBD-2 mRNA was detectable in only two of the ten samples. Of six corneas placed in to organ culture, hBD-1 mRNA expression was unchanged in the re-grown epithelial samples compared to the original epithelium samples, however the expression of hBD-2 mRNA was markedly increased. hBD-1 and hBD-2 peptides showed the same pattern of expression as their respective transcripts. CONCLUSIONS: These data show that hBD-2 mRNA and peptide is up-regulated in the corneal epithelium during re-epithelialization which is in keeping with the role of this defensin as an antimicrobial peptide.
Aged↗
Monoclonal antibodies against human telomerase reverse transcriptase (hTERT): preparation, characterization, and application.
The catalytic subunit of human telomerase reverse transcriptase (hTERT), is the necessary and rate-limiting component to telomerase activation in cancer cells. To develop monoclonal antibodies (MAbs) against hTERT, a peptide-hTERT(9)-derived from specific motif T of hTERT was synthesized. Through fusion of splenocytes of BALB/c mice immunized with hTERT(9) with mouse myeloma cells, hybridomas were generated and clones secreting anti-hTERT(9) antibody were screened. After three rounds of limited dilution of candidate clones, three of which present stable and constant antibody production. The MAbs were hTERT(9)-specific and reactive with native hTERT of human cancer cells or tissues in Western blot and immunohistochemistry. The heavy chain variable regions from three hybridomas were cloned and sequenced confirming their mouse Ig derivation. The described investigation suggested that the generated MAbs to hTERT(9) could recognize native hTERT and be useful to cancer research.
Amino Acid Sequence↗
Rapid determination of the binding affinity and specificity of the mushroom Polyporus squamosus lectin using frontal affinity chromatography coupled to electrospray mass spectrometry.
The binding affinity and specificity of the mushroom Polyporus squamosus lectin has been determined by the recently developed method of frontal affinity chromatography coupled to electrospray mass spectrometry (FAC/MS). A micro-scale affinity column was prepared by immobilizing the lectin ( approximately 25 microg) onto porous glass beads in a tubing column (9.8 microl column volume). The column was then used to screen several oligosaccharide mixtures. The dissociation constants of 22 sialylated or sulfated oligosaccharides were evaluated against the immobilized lectin. The lectin was found to be highly specific for Neu5Acalpha2-6Galbeta1-4Glc/GlcNAc containing oligosaccharides with K(d) values near 10 microM. The FAC/MS assay permits the rapid determination of the dissociation constants of ligands as well as a higher throughput screening of compound mixtures, making it a valuable tool for affinity studies, especially for testing large numbers of compounds.
Agaricales↗
The Drosophila homolog of mammalian zinc finger factor MTF-1 activates transcription in response to heavy metals.
Metallothioneins (MTs) are short, cysteine-rich proteins for heavy metal homeostasis and detoxification; they bind a variety of heavy metals and also act as radical scavengers. Transcription of mammalian MT genes is activated by heavy metal load via the metal-responsive transcription factor 1 (MTF-1), an essential zinc finger protein whose elimination in mice leads to embryonic lethality due to liver decay. Here we characterize the Drosophila homolog of vertebrate MTF-1 (dMTF-1), a 791-amino-acid protein which is most similar to its mammalian counterpart in the DNA-binding zinc finger region. Like mammalian MTF-1, dMTF-1 binds to conserved metal-responsive promoter elements (MREs) and requires zinc for DNA binding, yet some aspects of heavy metal regulation have also been subject to divergent evolution between Drosophila and mammals. dMTF-1, unlike mammalian MTF-1, is resistant to low pH (6 to 6.5). Furthermore, mammalian MT genes are activated best by zinc and cadmium, whereas in Drosophila cells, cadmium and copper are more potent inducers than zinc. The latter species difference is most likely due to aspects of heavy metal metabolism other than MTF-1, since in transfected mammalian cells, dMTF-1 responds to zinc like mammalian MTF-1. Heavy metal induction of both Drosophila MTs is abolished by double-stranded RNA interference: small amounts of cotransfected double-stranded RNA of dMTF-1 but not of unrelated control RNA inhibit the response to both the endogenous dMTF-1 and transfected dMTF-1. These data underline an important role for dMTF-1 in MT gene regulation and thus heavy metal homeostasis.
Amino Acid Sequence↗
Characteristics of colorectal cancer that produce positive immunochemical occult blood test results on stool obtained by digital rectal examination.
OBJECTIVE: To clarify the clinicopathological features of colorectal cancer that show positive results on an immunochemical fecal occult blood test of stool obtained by digital rectal examination. METHODS: In a cross-sectional study, 9952 subjects received both an immunochemical fecal occult blood test of stool obtained by digital rectal examination and colonoscopy annually over a nine-year period of medical checkups; 64 patients with colorectal cancer were identified. The study subjects comprised 39 patients with colorectal cancer who had positive results (positive group) and 25 patients with colorectal cancer who had negative results (negative group) on an immunochemical fecal occult blood test of stool obtained by digital rectal examination. The positive and negative groups were compared in terms of their individual factors, such as site, size, Dukes classification and histological type of the cancer lesions. RESULTS: The prevalence of rectal cancers was higher in the positive group than in the negative group (P<0.05), but there were no differences between the two groups with respect to any other factors. CONCLUSIONS: These findings indicate that stool obtained during the digital rectal examination is unsuitable for detecting fecal occult blood, especially for the detection of proximal colon neoplasms.
Adenocarcinoma↗
Polymorphisms in matrix metalloproteinase-1, -3, -9, and -12 genes in relation to subarachnoid hemorrhage.
BACKGROUND AND PURPOSE: Intracranial aneurysm, which underlies the vast majority of subarachnoid hemorrhage incidences, has a multifactorial etiology, and the importance of genetic factors is increasingly recognized. Development and rupture of intracranial aneurysms involve degradation and remodeling of the vascular wall matrix in which the matrix metalloproteinases (MMPs) play an important role. The possible impact of MMP gene polymorphisms on susceptibility to intracranial aneurysms is still controversial, with conflicting data from different reported studies. METHODS: In this study we analyzed 5 different functional promoter polymorphisms in the MMP-1, MMP-3, MMP-9, and MMP-12 genes in a sample of 92 patients with aneurysmal subarachnoid hemorrhage and 158 healthy control subjects, all from southern England. RESULTS: No significant difference was detected between the patient and control groups in genotype distribution of any of the polymorphisms studied. CONCLUSIONS: The data do not support the hypothesis that MMP gene variations influence the development of intracranial aneurysms in the population studied.
Adult↗
Drosophila Amphiphysin is implicated in protein localization and membrane morphogenesis but not in synaptic vesicle endocytosis.
Amphiphysin family members are implicated in synaptic vesicle endocytosis, actin localization and one isoform is an autoantigen in neurological autoimmune disorder; however, there has been no genetic analysis of Amphiphysin function in higher eukaryotes. We show that Drosophila Amphiphysin is localized to actin-rich membrane domains in many cell types, including apical epithelial membranes, the intricately folded apical rhabdomere membranes of photoreceptor neurons and the postsynaptic density of glutamatergic neuromuscular junctions. Flies that lack all Amphiphysin function are viable, lack any observable endocytic defects, but have abnormal localization of the postsynaptic proteins Discs large, Lethal giant larvae and Scribble, altered synaptic physiology, and behavioral defects. Misexpression of Amphiphysin outside its normal membrane domain in photoreceptor neurons results in striking morphological defects. The strong misexpression phenotype coupled with the mild mutant and lack of phenotypes suggests that Amphiphysin acts redundantly with other proteins to organize specialized membrane domains within a diverse array of cell types.
Actins↗
The D allele of the angiotensin-converting enzyme gene and reperfusion-induced ventricular arrhythmias in patients with acute myocardial infarction.
The renin-angiotensin system may play a pivotal role in reperfusion ventricular arrhythmias (RVA). The purpose of this study was to investigate the association between angiotensin-converting enzyme (ACE) gene polymorphism and RVA in patients with acute myocardial infarction (AMI) in a case-control study. Patients who had undergone successful coronary intervention for AMI were enrolled (n= 127, male/female: 97/30, mean age, 62.6 years). The incidence of RVA was continuously monitored by ECG at a coronary care unit. The severity of ventricular arrhythmias was evaluated in terms of the Lown's grade and patients with a high risk of ventricular arrhythmias that may cause sudden cardiac death (Lown's grade > or =2) within 5 h of coronary intervention were defined as cases (n=59), and otherwise as controls (n=68). A receiver operating characteristic curve was used to determine the discriminatory ability of continuous variables and to produce dummy variables for use in a logistic regression analysis. Cases had a significantly higher body mass index, higher maximal levels of serum creatine kinase, and a shorter time preceding coronary intervention than controls. The severity of coronary atherosclerosis was similar between the 2 groups. The frequency distribution of ACE genotypes in cases differed from that in controls (II/ID/DD: 22.0%/52.6%/25.4% vs 44.1%/41.4%/14.7%, p<0.05, by the Mantel-Haenzel chi-square test). The ACE-D allele had additive and dominant effects with regard to the occurrence of significant ventricular arrhythmias after adjusting for other risk factors. The ACE-D allele may play a pivotal role in sudden cardiac death in patients with AMI.
Accelerated Idioventricular Rhythm↗
The effect of Bcl-2 adenovirus against murine hepatocyte apoptosis caused by tumor necrosis factor alpha and D-galactosamine.
OBJECTIVE: To evaluate the role of Bcl-2 family proteins in hepatic apoptosis caused by TNF-alpha and D-galactosamine. METHODS: We induced mouse liver injury with TNF-alpha and D-galactosamine, and detected hepatic apoptosis, the expression of Bcl-2, Bax, and Bak proteins on hepatocytes by using TUNEL or immunohistochemistry, respectively. We also observed the expression of Bcl-2 protein on hepatocytes infected with Bcl-2 adenovirus vector and its protection against hepatocyte apoptosis. RESULTS: Hepatocyte apoptosis was induced in BalB/c mice pretreated with TNF-alpha plus D-galactosamine, accompanying the enhanced expression of Bax, Bak proteins in hepatocytes. Bcl-2 protein was expressed in murine hepatocytes and lasted at least 1 month after injection of Bcl-2 adenovirus vector, which also lowered ALT level from (1372.9+/-251.4)U/L to (796.5+/-78.7)U/L and reduced hepatocyte apoptosis caused by TNF-alpha and D-galactosamine. CONCLUSIONS: The enhanced expression of Bax, Bak proteins may play a role in hepatocyte apoptosis induced by TNF-alpha and D-galactosamine. D-galactosamine adenovirus vector can partially reduced hepatocyte apoptosis induced by TNF- alpha and D-galactosamine.
Adenoviridae↗
Changes and significance of circulating hepatocellular carcinoma cells in recurrent hepatocellular carcinoma patients after combined treatment.
OBJECTIVE: To study the changes and significance of circulating hepatocellular carcinoma cells in recurrent hepatocellular carcinoma (HCC) patients after combined treatment of transarterial chemo-embolization(TACE) and percutaneous ethanol injection(PEI). METHODS: We detected 19 blood samples from the recurrent HCC patients by nested RT-PCR to find out AFP mRNA before and after the treatment. RESULTS: There were 7 patients with AFP mRNA positive before treatment (36.8%), and none of patients with AFP mRNA positive after treatment. CONCLUSIONS: Combined treatment of TACE and PEI can effectively eliminate circulating hepatocellular carcinoma cells and thereby prevent metastasis and recurrence of HCC.
Adult↗