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991.
Bacillus cereus 569 (ATCC 10876) germinates in response to inosine or to L-alanine, but the most rapid germination response is elicited by a combination of these germinants. Mutants defective in their germination response to either inosine or to L-alanine were isolated after Tn917-LTV1 mutagenesis and enrichment procedures; one class of mutant could not germinate in response to inosine as a sole germinant but still germinated in response to L-alanine, although at a reduced rate; another mutant germinated normally in response to inosine but was slowed in its germination response to L-alanine. These mutants demonstrated that at least two signal response pathways are involved in the triggering of germination. Stimulation of germination in L-alanine by limiting concentrations of inosine and stimulation of germination in inosine by low concentrations of L-alanine were still detectable in these mutants, suggesting that such stimulation is not dependent on complete functionality of both these germination loci. Two transposon insertions that affected inosine germination were found to be located 2.2 kb apart on the chromosome. This region was cloned and sequenced, revealing an operon of three open reading frames homologous to those in the gerA and related operons of Bacillus subtilis. The individual genes of this gerI operon have been named gerIA, gerIB, and gerIC. The GerIA protein is predicted to possess an unusually long, charged, N-terminal domain containing nine tandem copies of a 13-amino-acid glutamine- and serine-rich sequence. 相似文献
992.
S Shahabuddin I Al-Ayed MO Gad El-Rab MI Qureshi 《Canadian Metallurgical Quarterly》1998,5(5):632-635
The age-related changes in absolute and percentage values of lymphocyte subsets in the peripheral blood of healthy children of different ages (1 month to 13 years) were studied by flow cytometry. The absolute and percentage values for most lymphocyte subpopulations differed substantially with age. Comparisons among age groups from infants through adults revealed progressive declines in the absolute numbers of leukocytes, total lymphocytes, and T, B, and natural killer (NK) cells. The percentages of T cells increased with age. Within the T-lymphocyte population, the CD8(+) subset increased but the CD4(+) subset decreased, resulting in a declining CD4(+)/CD8(+) ratio. The percentage of B cells declined, but that of NK cells remained unchanged. The percentage of HLA-DR+ T cells increased over time, but their number changed inconsistently. Our findings confirm and extend earlier reports on age-related changes in lymphocyte subpopulations. These data should be useful in the interpretation of disease-related changes, as well as therapy-dependent alterations, in lymphocyte subsets in children of different age groups. 相似文献
993.
SF Keevil B Barbiroli JC Brooks EB Cady R Canese P Carlier DJ Collins P Gilligan G Gobbi J Hennig H Kügel MO Leach D Metzler V Mlynárik E Moser MC Newbold GS Payne P Ring JN Roberts IJ Rowland T Thiel I Tkác S Topp HJ Wittsack F Podo 《Canadian Metallurgical Quarterly》1998,16(9):1093-1106
We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy. 相似文献
994.
K Liitsola I Tashkinova T Laukkanen G Korovina T Smolskaja O Momot N Mashkilleyson S Chaplinskas H Brummer-Korvenkontio J Vanhatalo P Leinikki MO Salminen 《Canadian Metallurgical Quarterly》1998,12(14):1907-1919
OBJECTIVES: To investigate the molecular epidemiology and genetic structure of the virus strain(s) causing an outbreak of HIV-1 infection in the Kaliningrad province of the Russian Federation and to investigate the relationship of this outbreak to some other emerging HIV-1 epidemics in the countries of the former Soviet Union. DESIGN: A molecular epidemiological investigation was conducted in the city of Kaliningrad amongst individuals recently diagnosed as HIV-1-positive. Samples were also collected from neighbouring Lithuania and from the Ukraine. METHODS: Incident and population data was collected from official health statistics in Kaliningrad. A standardized questionnaire was administered to newly diagnosed individuals to assess risk factors for HIV-1 infection. For genotyping, two regions of the virus (env C2-V3 and gag NCp7) were directly sequenced. RESULTS: The number of newly diagnosed individuals testing seropositive for HIV-1 infection in Kaliningrad rose from less than one per month to more than 100 per month during the period of July-October 1996. A total of 1335 new infections were identified between 1 July 1996 and 30 June 1997. The main reported risk factor for HIV-1 infection (80%) was injecting drug use, in particular with a locally produced opiate. Sequence analysis of patient viruses in Kaliningrad (n = 50) showed that the epidemic was caused by a highly homogenous HIV-1 strain, recombinant between the genetic subtypes A and B. Comparison with subtype A strains prevalent amongst injecting drug users (IDU) in the Ukraine showed that one of these strains was the direct subtype A parent of the epidemic A/B recombinant strain in Kaliningrad. CONCLUSIONS: The HIV-1 epidemic in Kaliningrad probably started from a single source, with rapid spread of the virus through the IDU population. The origin of the epidemic strain is a recombination event occurring between the subtype A strain virus prevalent among IDU in some southern CIS countries, and a subtype B strain of unknown origin. 相似文献
995.
996.
Prevalence of diabetes in rural and urban populations in southern Sierra Leone: a preliminary survey
MM Ceesay MW Morgan MO Kamanda VR Willoughby DR Lisk 《Canadian Metallurgical Quarterly》1997,2(3):272-277
BACKGROUND: Immunodominant epitopes of Bet v 1a had been identified before, using recombinant (r) Bet v 1a-reactive T cell clones generated from peripheral blood mononuclear cells of patients allergic to birch pollen. This study aimed at evaluating the T cell-stimulating capacity of immunodominant Bet v 1a-derived peptides in a polyclonal system corresponding more closely to the situation in patients. METHODS: Short-term T cell lines (TCL) were established in presence of a protein extract of birch pollen (BP extract). TCL proliferation induced by the BP extract, by natural Bet v 1, rBet v 1a, rBet v 2 or 5 selected immunodominant Bet v 1a-derived peptides was determined. RESULTS: Consistent with the knowledge that Bet v 1 is the major IgE-binding allergen of birch pollen, we found comparable T cell reactivity to natural Bet v 1 and the BP extract within the majority of the TCL. Accordingly, the response to rBet v 2 was low compared with the reactivity to the BP extract. The response of the TCL to rBet v 1a proved to be highly heterogeneous. Furthermore, the TCL response to the 5 immunodominant Bet v 1a-derived peptides showed considerable diversity. The proliferative responses of most TCL (with one exception) following stimulation by these peptides were low, in relation to the expansion induced by the BP extract. CONCLUSION: These findings argue against the use of selected peptides derived from Bet v 1a in specific immunotherapy of patients with birch allergy. 相似文献
997.
HJ Super NR McCabe MJ Thirman RA Larson MM Le Beau J Pedersen-Bjergaard P Philip MO Diaz JD Rowley 《Canadian Metallurgical Quarterly》1993,82(12):3705-3711
Chromosome band 11q23 is frequently involved in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) de novo, as well as in myelodysplastic syndromes (MDS) and lymphoma. Five percent to 15% of patients treated with chemotherapy for a primary neoplasm develop therapy-related AML (t-AML) that may show rearrangements, usually translocations involving band 11q23 or, less often, 21q22. These leukemias develop after a relatively short latent period and often follow the use of drugs that inhibit the activity of DNA-topoisomerase II (topo II). We previously identified a gene, MLL (myeloid-lymphoid leukemia or mixed-lineage leukemia), at 11q23 that is involved in the de novo leukemias. We have studied 17 patients with t-MDS/t-AML, 12 of whom had cytogenetically detectable 11q23 rearrangements. Ten of the 12 t-AML patients had received topo II inhibitors and 9 of these, all with balanced translocations of 11q23, had MLL rearrangements on Southern blot analysis. None of the patients who had not received topo II inhibitors showed an MLL rearrangement. Of the 5 patients lacking 11q23 rearrangements, some of whom had monoblastic features, none had an MLL rearrangement, although 4 had received topo II inhibitors. Our study indicates that the MLL gene rearrangements are similar both in AML that develops de novo and in t-AML. The association of exposure to topo II-reactive chemotherapy with 11q23 rearrangements involving the MLL gene in t-AML suggests that topo II may play a role in the aberrant recombination events that occur in this region both in AML de novo and in t-AML. 相似文献
998.
MO Olatawura 《Canadian Metallurgical Quarterly》1976,5(1):67-92
An analysis of the result of administering electroconvulsive therapy (E.C.T.) to 292 patients suffering predominantly from psychosis and depression is presented. The results show that the courses of E.C.T. administered range from three to twenty-five. The most frequently administered course was six to eight. Favourable response to treatment was reported in all diagnostic groups immediately after completing the course but less so in cases of depression and paranoid schizophrenia. The reasons thought to account for this were discussed. It is concluded that there is need for careful selection of patients for E.C.T. 相似文献
999.
T Obeid MO el Rab AK Daif CP Panayiotopoulos K Halim H Bahakim E Bamgboye 《Canadian Metallurgical Quarterly》1994,35(2):319-321
In a study of 32 unrelated Arab patients with juvenile myoclonic epilepsy (JME), we compared the frequencies of human leukocyte antigen (HLA) class I and II alleles with those of unrelated healthy controls. A significant difference between the phenotypic frequencies in JME patients and controls was observed for DRW13, the split of DRW6 (37.5 vs 11% of controls). The strength of association as measured by the relative risk was 4.85 for this antigen (p = 0.002). The possible association of JME with HLA-DRW6 recently reported in Caucasians was confirmed in this study. This finding speaks for the homogeneity of the disease among Arabic and Caucasian JME patients. The existence of this association is evidence of a locus in the HLA region that influences expression of JME. 相似文献
1000.