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81.
Heat Shock Protein 70 of the Agent of Human Granulocytic Ehrlichiosis Binds to Borrelia burgdorferi Antibodies
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Jacob W. Ijdo Yan Zhang Matthew L. Anderson David Goldberg Erol Fikrig 《Clinical and Vaccine Immunology : CVI》1998,5(1):118-120
We describe a patient with human granulocytic ehrlichiosis (HGE), a diagnosis confirmed by PCR and immunoblot analysis. Unexpectedly, immunoglobulin G (IgG) directed towards an 80-kDa ehrlichial antigen (without detectable IgM) was present in the patient’s serum in the first week of illness. Lyme disease immunoblots were reactive for IgG (but not IgM), a result indicative of prior exposure to the Lyme disease spirochete. Amino-terminal sequencing revealed that the 80-kDa ehrlichial antigen was an HSP-70 homolog similar to Borrelia burgdorferi HSP-70. We conclude that antibodies against B. burgdorferi HSP-70 may cross-react with the ehrlichial heat shock protein and that this possibility must be considered when serologic test results for HGE and Lyme disease are interpreted. 相似文献
82.
Tangir J Bonafé N Gilmore-Hebert M Henegariu O Chambers SK 《Clinical & experimental metastasis》2004,21(6):477-483
The aggressive behavior of breast cancer cells can at times be modulated by hormonal mechanisms. Exposure to glucocorticoids
(GC) has been shown to stimulate the invasiveness, motility and adhesiveness of breast cancer cells containing the glucocorticoid
receptor. This is largely explained by GC-associated overexpression of the c-fms proto-oncogene, which encodes the receptor for the colony stimulating factor-1 (CSF-1). Our objective is to investigate additional
GC-associated genetic alterations that could modulate c-fms related malignant behavior in breast cancer cells. A microarray technique using an oligonucleotide array representing 16,700
known expressed human genes was used to analyze the gene expression profile of breast cancer cells exposed to dexamethasone
(Dex) or vehicle. Results were confirmed by western blot analysis. Six genes were found to be consistently differentially
overexpressed in the Dex-exposed cells compared to control. We focused on serum-glucose kinase 1 (SGK1), a serine-threonine
kinase known to be involved in intracellular signal transduction pathways and induced by GC and serum. An adhesion assay was
performed on extracellular matrix after exposing the breast cancer cells to Dex, CSF-1 or to Dex or CSF-1 plus LY294002, a
functional inhibitor of SGK1 action. Exposure to LY294002 significantly decreased both CSF-1 and Dex-induced adhesiveness
to the level of control cells. SGK1 may act as a downstream intracellular regulator of c-fms, particularly of c-fms-induced adhesiveness of breast cancer cells after exposure to GC or CSF-1. This finding may have implications for potential
therapeutic interventions aimed at decreasing the aggressiveness of breast cancer cells.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
83.
Comparative recombination rates in the rat, mouse, and human genomes 总被引:18,自引:3,他引:18
Jensen-Seaman MI Furey TS Payseur BA Lu Y Roskin KM Chen CF Thomas MA Haussler D Jacob HJ 《Genome research》2004,14(4):528-538
Levels of recombination vary among species, among chromosomes within species, and among regions within chromosomes in mammals. This heterogeneity may affect levels of diversity, efficiency of selection, and genome composition, as well as have practical consequences for the genetic mapping of traits. We compared the genetic maps to the genome sequence assemblies of rat, mouse, and human to estimate local recombination rates across these genomes. Humans have greater overall levels of recombination, as well as greater variance. In rat and mouse, the size of the chromosome and proximity to telomere have less effect on local recombination rate than in human. At the chromosome level, rat and mouse X chromosomes have the lowest recombination rates, whereas human chromosome X does not show the same pattern. In all species, local recombination rate is significantly correlated with several sequence variables, including GC%, CpG density, repetitive elements, and the neutral mutation rate, with some pronounced differences between species. Recombination rate in one species is not strongly correlated with the rate in another, when comparing homologous syntenic blocks of the genome. This comparative approach provides additional insight into the causes and consequences of genomic heterogeneity in recombination. 相似文献
84.
cagA-Positive Helicobacter pylori Populations in China and The Netherlands Are Distinct 总被引:9,自引:0,他引:9
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Arie van der Ende Zhi-Jun Pan Aldert Bart Ren W. M. van der Hulst Monique Feller Shu-Dong Xiao Guido N. J. Tytgat Jacob Dankert 《Infection and immunity》1998,66(5):1822-1826
The aim of this research was to study whether and to what extent Chinese cagA-positive Helicobacter pylori isolates differ from those in The Netherlands. Analysis of random amplified polymorphic DNA (RAPD)-PCR-assessed DNA fingerprints of chromosomal DNA of 24 cagA-positive H. pylori isolates from Dutch (n = 12) and Chinese (n = 10) patients yielded the absence of clustering. Based on comparison of the sequence of a 243-nucleotide part of cagA, the Dutch (group I) and Chinese (group II) H. pylori isolates formed two separate branches with high confidence limits in the phylogenetic tree. These two clusters were not observed when the sequence of a 240-bp part of glmM was used in the comparison. The number of nonsynonymous substitutions was much higher in cagA than in glmM, indicating positive selection. The average levels of divergence of cagA at the nucleotide and protein levels between group I and II isolates were found to be high, 13.3 and 17.9%, respectively. Possibly, the pathogenicity island (PAI) that has been integrated into the chromosome of the ancestor of H. pylori now circulating in China contained a different cagA than the PAI that has been integrated into the chromosome of the ancestor of H. pylori now circulating in The Netherlands. We conclude that in China and The Netherlands, two distinct cagA-positive H. pylori populations are circulating. 相似文献
85.
Expression of a novel combination of fast and slow troponin T isoforms in rabbit extraocular muscles
Margaret M. Briggs Jean Jacoby Jacob Davidowitz Frederick H. Schachat 《Journal of muscle research and cell motility》1988,9(3):241-247
Summary The properties of extraocular muscles (EOMs) are quite different from those of the trunk and limb. Here we show that there is a novel pattern of troponin T (TnT) expression in EOMs which most likely contributes to the fine control of ocular movement and may reflect their innervation by cranial motoneurons. Three regions of the muscle were analysed to distinguish the TnT isoforms present in the fast singly-innervated fibres from those in the multiply-innervated fibres. More than 95% of the TnT in the singly-innervated fibres is TnT3f, which exhibits the most graded response to changes in calcium concentration during activation (Schachatet al., J. molec. Biol.
198, 551–4). In multiply-innervated fibres, which exhibit tonic contractures, the slow troponin T TnT2s is expressed. While neither TnT3f nor TnT2s is unique to EOM, this pattern is unusual in two respects: first, both TnT3f and TnT2s are minor components of the trunk and limb musculature, and second, most muscles express several fast and both slow TnT species. Although EOM occupies a highly specialized physiological niche, its unusual physiology is not reflected in the presence of new TnT isoforms but in the expression of a different ratio of the known species of TnT. 相似文献
86.
The purpose of this study was to assess the knowledge, practices and attitudes towards HIV Positive/AIDS patients among 112 dentists from public institutions in Nairobi using a self-administered questionnaire. 94(83.9%) responded. Over 74% had managed HIV positive/AIDS patients. In general, respondents' knowledge and preventive measures against HIV infection were satisfactory. 8.5% did not find use of protective eye wear absolutely necessary. 33% used protective covers routinely. 52.1% advocated for the screening of all suspected cases of AIDS before treatment. 27.7% felt that HIV positive health workers and those with AIDS should not be allowed to treat patients. 53.2% felt that they should be given the right to decide on treating HIV Positive/AIDS patients. 10.6% supported the idea that AIDS patients be isolated from uninfected individuals. It is concluded that a substantial number of dentists were wanting in their attitudes towards HIV positive/AIDS patients. 相似文献
87.
L-carnitine: metabolism, functions and value in pathology] 总被引:1,自引:0,他引:1
Although L-carnitine is not considered as an essential nutrient, endogenous synthesis may fail to ensure adequate L-carnitine levels in neonates, especially those born prematurely. Free L-carnitine is found in many foods, mainly those from animal sources. Absorption of free L-carnitine is virtually complete. Lysine and methionine are necessary ingredients for the biosynthesis of L-carnitine. All tissues in the body can produce deoxy-carnitine but, in humans, the enzyme that enables hydroxylation of deoxy-carnitine to carnitine is found only in the liver, brain and kidneys. Complex exchanges of carnitine and its precursors occur between tissues. Muscles take up carnitine from the bloodstream and contain most of the body carnitine stores. L-carnitine and L-carnitine esters are eliminated mainly through the kidneys, which may play a central role in the homeostasis of this compound. Thyroid hormones adrenocorticotrophin (ACTH), and diet all influence urinary excretion of L-carnitine. Free L-carnitine can be assayed in plasma and urine and is occasionally measured in muscle biopsy specimens. Plasma L-carnitine levels may not accurately reflect L-carnitine body stores. L-carnitine ensures transfer of fatty acids to the mitochondria where they undergo oxidation. This process is associated with production of short-chain acylcarnitine which exit from the mitochondria or peroxisomes. L-carnitine ensures regeneration of coenzyme A and is thus involved in energy metabolism. L-carnitine also ensures elimination of xenobiotic substances. Carnitine deficiencies are common. Currently, these deficiencies are classified into two groups. In deficiencies with myopathy, only the muscles are deficient in L-carnitine, perhaps as a result of a primary anomaly of the L-carnitine transport system in muscles. In systemic deficiencies, L-carnitine levels are low in the plasma and in all body tissues. Systemic L-carnitine deficiencies are usually the result of a variety of disease states including deficient intake in premature infants or long-term parenteral nutrition; renal failure; organic acidemias; and Reye's syndrome. Modifications in L-carnitine metabolism have also been reported in patients with diabetes mellitus, malignancies, myocardial ischemia, and alcohol abuse. A large number of supplementation trials have been carried out. 相似文献
88.
Bareket Falk Ruth Burstein Isaack Ashkenazi Ofer Spilberg Jacob Alter Ester Zylber-Katz Ardon Rubinstein Nava Bashan Yair Shapiro 《European journal of applied physiology》1989,59(3):168-173
Summary The purpose of this study was to determine the effect of caffeine ingestion on physical performance after prolonged endurance
exercise. Twenty three trained male volunteers participated in a 40-km march and were divided into two groups, matched for
caffeine clearance rate and aerobic capacity. The experimental group ingested, prior to the march, a caffeinated drink at
a dose of 5 mg·kg−1 body mass and at the 3rd and 5th h of marching an additional drink at a dose of 2.5 mg·kg−1 body mass. The control group ingested a drink of equal volume at the same times. Upon termination of the march each subject
performed a cycle ergometer test at an intensity of 90% maximal oxygen consumption. Time to exhaustion and rate of perceived
exertion (RPE) were recorded. Blood samples were drawn predrink, at the 3rd and 5th h of marching and immediately after the
cycle ergometer test, and were analysed for caffeine, free fatty acids (FFA), lactate and glucose levels. Plasma FFA levels
increased during the march (p<0.05), with no significant difference between groups. Lactate levels increased in the experimental group (p<0.05), with no significant change in the control group. Glucose levels did not change significantly in either group. After
the cycle ergometer test, lactate levels were significantly higher in the experimental, as compared to the control group (3.77±0.33
vs 2.52±0.35 mmol·l−1, respectively). There was no significant difference between treatments in the time to exhaustion on the cycle ergometer,
but RPE was different (p<0.05). Under the conditions of this study, the results do not indicate caffeine ingestion as an ergogenic aid which will
postpone exhaustion following prolonged endurance exercise.
This work was presented, in part, at the Canadian Association of Sports Sciences Annual Meeting, October 1987, Lake Louise,
Alberta, Canada 相似文献
89.
Molecular determinants of human uveal melanoma invasion and metastasis 总被引:19,自引:0,他引:19
Seftor EA Meltzer PS Kirschmann DA Pe'er J Maniotis AJ Trent JM Folberg R Hendrix MJ 《Clinical & experimental metastasis》2002,19(3):233-246
The molecular analysis of cancer has benefited tremendously from the sequencing of the human genome integrated with the science
of bioinformatics. Microarray analysis technology has the potential to classify tumors based on the differential expression
of genes. In the current study, a collaborative, multidisciplinary approach was utilized to study the molecular determinants
of human uveal melanoma invasion and metastasis. Uveal melanoma is considered the most common primary intraocular cancer in
adults, resulting in the death of approximately 50% of patients affected. Unfortunately, at the time of diagnosis, many patients
already harbor microscopic metastases, thus underscoring a critical need to identify prognostic markers indicative of metastatic
potential. The investigative strategy consisted of isolating highly invasive vs. poorly invasive uveal melanoma cells from
a heterogeneous tumor derived from cells that had metastasized from the eye to the liver. The heterogeneous tissue explant
MUM-2 led to the derivation of two clonal cell lines: MUM-2B and MUM-2C. Further morphological and functional analyses revealed
that the MUM-2B cells were epithelioid, interconverted (expressing mesenchymal and epithelial phenotypes) highly invasive,
and demonstrated vasculogenic mimicry. The MUM-2C cells were spindle-like, expressed only a vimentin mesenchymal phenotype,
poorly invasive, and were incapable of vasculogenic mimicry. The molecular analysis of the MUM-2B vs. the MUM-2C clones resulted
in the differential expression of 210 known genes. Overall, the molecular signature of the MUM-2B cells resembled that of
multiple phenotypes – similar to a pluripotent, embryonic-like genotype. Validation of select genes that were upregulated
and down-regulated was conducted by semiquantitative RT-PCR measurement. This study provides a molecular profile that will
hopefully lead to the development of new molecular targets for therapeutic intervention and possible diagnostic markers to
predict the clinical outcome of patients with uveal melanoma.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
90.
Ueno T Tremblay J Kunes J Zicha J Dobesova Z Pausova Z Deng AY Sun YL Jacob HJ Hamet P 《Journal of molecular medicine (Berlin, Germany)》2003,81(1):51-60
Acute pharmacogenetic analysis was carried out in an intercross F2 population derived from Prague hypertensive-hypertriglyceridemic and Lewis rats. Quantitative trait loci (QTL) mapping was performed for baseline blood pressure (BP) and for BP after blockade of the renin-angiotensin system by losartan, of the sympathetic nervous system (SNS) by pentolinium, and of the nitric oxide system by N(G)-nitro- L-arginine methyl ester. Two significant loci for baseline BP were found on chromosome (Chr) 3 (logarithm of likelihood, LOD, 3.8) and Chr 5 (LOD 3.6), and one suggestive locus on Chr 1 (LOD 2.7). The QTL on Chr 3 persisted after treatment with the three agents while the QTL on Chr 5 and Chr 1 disappeared after pentolinium administration. This suggests independence of the locus on Chr 3 from each acute BP regulatory system examined, whereas the loci on Chr 5 and Chr 1 appeared to be controlled mainly by the SNS. Although not apparent at baseline, a significant locus appeared on Chr 8 (LOD 7.0) after blockade of the SNS, and NO system blockade led to the appearance of a new QTL on Chr 1 (LOD 3.6), indicating the contribution of the inhibited systems to these loci. Pharmacogenetic dissection of the BP trait is a powerful tool to unravel the underlying physiological mechanisms of QTL affecting baseline BP and to identify specific QTL for the response to drugs. This pharmocogenetic approach enabled us to determine the main causative acute BP regulatory systems and should lead to better selection of suitable antihypertensive drugs for individual patients. 相似文献