Association of CD14 G(-1145)A and C(-159)T polymorphisms with reduced risk for tuberculosis in a Chinese Han population.

Although the role of CD14 in mediating signals from Toll-like receptors to recognize Mycobacterium tuberculosis is known, how polymorphisms in this gene affect the susceptibility to develop tuberculosis are still not clear. We examined whether single nucleotide polymorphisms at positions -1145 and -159 in the promoter region of the CD14 gene are associated with tuberculosis in a Chinese Han population in a case-control study of 432 Chinese patients with tuberculosis and 404 ethnically matched healthy controls. Genotyping was performed to identify polymorphisms of the CD14 gene by PCR-DNA sequencing. Both the frequency of allele T in the C(-159)T polymorphism (odds ratio (OR) = 1.4; 95% confidence interval (95%CI) = 1.148-1.708) and allele G in the G(-1145)A polymorphism (OR = 1.512; 95%CI = 1.236- 1.849) were significantly more frequent in cases than in controls. The frequencies of genotypes CC and CT in the C(-159)T polymorphism, as well as the frequencies of genotypes AA and AG, were lower in cases than in controls. Based on our results, we conclude that G(-1145)A and C(-159)T polymorphisms of CD14 are associated with decreased risk for the development of tuberculosis in the Chinese Han population.

Differences in antigen presentation to MHC class I-and class II-restricted influenza virus-specific cytolytic T lymphocyte clones.

We have examined requirements for antigen presentation to a panel of MHC class I-and class II-restricted, influenza virus-specific CTL clones by controlling the form of virus presented on the target cell surface. Both H-2K/D- and I region-restricted CTL recognize target cells exposed to infectious virus, but only the I region-restricted clones efficiently lysed histocompatible target cells pulsed with inactivated virus preparations. The isolated influenza hemagglutinin (HA) polypeptide also could sensitize target cells for recognition by class II-restricted, HA-specific CTL, but not by class I-restricted, HA-specific CTL. Inhibition of nascent viral protein synthesis abrogated the ability of target cells to present viral antigen relevant for class I-restricted CTL recognition. Significantly, presentation for class II-restricted recognition was unaffected in target cells exposed to preparations of either inactivated or infectious virus. This differential sensitivity suggested that these H-2I region-restricted CTL recognized viral polypeptides derived from the exogenously introduced virions, rather than viral polypeptides newly synthesized in the infected cell. In support of this contention, treatment of the target cells with the lysosomotropic agent chloroquine abolished recognition of infected target cells by class II-restricted CTL without diminishing class I-restricted recognition of infected target cells. Furthermore, when the influenza HA gene was introduced into target cells without exogenous HA polypeptide, the target cells that expressed the newly synthesized protein product of the HA gene were recognized only by H-2K/D-restricted CTL. These observations suggest that important differences may exist in requirements for antigen presentation between H-2K/D and H-2I region-restricted CTL. These differences may reflect the nature of the antigenic epitopes recognized by these two CTL subsets.

Influence of the axotomy to cell body distance in rat rubrospinal and spinal motoneurons: differential regulation of GAP-43, tubulins, and neurofilament-M.

Axotomized motoneurons regenerate their axons regardless of whether axotomy occurs proximally or distally from their cell bodies. In contrast, regeneration of rubrospinal axons into peripheral nerve grafts has been detected after cervical but not after thoracic injury of the rubrospinal tract. By using in situ hybridization (ISH) combined with reliable retrograde tracing methods, we compared regeneration-associated gene expression after proximal and distal axotomy in spinal motoneurons versus rubrospinal neurons. Regardless of whether they were axotomized at the iliac crest (proximal) or popliteal fossa (distal), sciatic motoneurons underwent highly pronounced changes in ISH signals for Growth Associated Protein 43 (GAP-43) (10-20x increase) and neurofilament M (60-85% decrease). In contrast, tubulin ISH signals substantially increased only after proximal axotomy (3-5x increase). To compare these changes in gene expression with those of axotomized rubrospinal neurons, the rubrospinal tract was transected at the cervical (proximal) or thoracic (distal) levels of the spinal cord. Cervically axotomized rubrospinal neurons showed three- to fivefold increases in ISH signals for GAP-43 and tubulins (only transient) and a 75% decrease for neurofilament-M. In sharp contrast, thoracic axotomy had only marginal effects. After implantation of peripheral nerve transplants into the spinal cord injury sites, retrograde labeling with the sensitive retrograde tracer Fluoro-Gold identified regenerating rubrospinal neurons only after cervical axotomy. Furthermore, rubrospinal neurons specifically regenerating into the transplants were hypertrophied and expressed high levels of GAP-43 and tubulins. Taken together, these data support the concept that, even if central nervous system (CNS) axons are presented with a permissive/supportive environment, appropriate cell body responses to injury are a prerequisite for CNS axonal regeneration.

Mathematical model for addiction: application to multiple risk factor intervention trial data for smoking.

Describes habituation and addiction, both psychological and physiological, using the simple equations of the mathematical model of ideodynamics. The parameters in these equations were optimized to smoking data from the Multiple Risk Factor Intervention Trial (MRFIT) program. With only 4 constant parameters, it was possible to calculate accurate time trends for recidivism to smoking among quitters, time trends for secondary cessation among recidivists, and final percentage of smokers in a population with both recidivism and secondary cessation occurring simultaneously. These same parameters further permit predictions for the long-range success of intervention programs to decrease substance dependency. Ideodynamics can also predict time trends of public opinion based on stories in the mass media.

Use of open-ended essays and computer content analysis to survey college students' knowledge of AIDS.

This study used computer content analysis of written essays to explore university students' knowledge and attitudes about AIDS. Because the essays were long, averaging 650 words each, and were on the very general topics of what individuals and society should do about AIDS, it was possible to study a wide variety of subjects. Computer scoring of the essays showed that education and individual changes in sexual behavior were the two methods of prevention mentioned most often. The majority of students accurately identified the most important methods of transmitting the disease. Only one fourth of the respondents discussed casual contact; a majority of those knew that the disease could not be transmitted in this manner. A minority of the students advocated isolating people infected with HIV or marking these individuals in ways that are accessible to others in society. The new computer methods used to analyze the essays offer flexible and efficient procedures for analyzing text on a variety of topics.

Impact of the mass media on calls to the CDC National AIDS Hotline.

This paper considers new computer methodologies for assessing the impact of different types of public health information. The example used public service announcements (PSAs) and mass media news to predict the volume of attempts to call the CDC National AIDS Hotline from December 1992 through to the end of 1993. The analysis relied solely on data from electronic databases. Newspaper stories and television news transcripts were obtained from the NEXIS electronic database and were scored by machine for AIDS coverage. The PSA database was generated by computer monitoring of advertising distributed by the Centers for Disease Control and Prevention (CDC) and by others. The volume of call attempts was collected automatically by the public branch exchange (PBX) of the Hotline telephone system. The call attempts, the PSAs and the news story data were related to each other using both a standard time series method and the statistical model of ideodynamics. The analysis indicated that the only significant explanatory variable for the call attempts was PSAs produced by the CDC. One possible explanation was that these commercials all included the Hotline telephone number while the other information sources did not.

News media framing sets public opinion that drugs is the country's most important problem.

Responses by the public to the question of whether drugs was the United States' most important problem ranged from under 5% to over 60% during the 9 years from 1985 to 1994. Time series analysis showed that changes in this opinion could be explained by the press describing drugs as a crisis. Other types of drug discussion contributed negligibly. In the reverse direction, public opinion about drugs was a weak but significant contributor to press coverage.

Quantitative estimates for the effects of AIDS public education on HIV infections.

Previous projections of HIV infection have not accounted explicitly for AIDS public information. The present analysis does so, using computer content analysis of AIDS news stories to make time trend forecasts of both HIV infection and knowledge, attitudes, and sexual behaviors relevant to AIDS. The data show that there was a rapid rise in infections before public information took effect. Then news about AIDS, its modes of transmission and high risk groups led to a 3-4-fold decrease in high risk sex among gay/bisexual men by the late 1980s. The result was a diminished infection rate saving 580,000 to 1.9 million lives. In more recent times, rates of HIV infection are forecast to increase again, although slowly, in small part because people are less prudent and in large part because the pool of infected individuals has greatly expanded.

Cell wall binding properties of the Bacillus subtilis autolysin(s).

Cell walls isolated from exponentially growing Bacillus subtilis have autolysin(s) attached to them. An autolysin can be released from the walls by incubation at 0 C with 3 m LiCl. The enzyme can reattach to walls when the salt concentration is reduced. The bound enzyme cannot be removed or destroyed by washing the walls with 8 m urea at 0 C. The binding of free enzyme to walls at 0 C can take place normally in the presence of 2 m urea.

Autolysin(s) of Bacillus subtilis as dechaining enzyme.

Bacillus subtilis bacteria grow exponentially as long filaments in well-aerated cultures at 48 C. These filaments are chains of cells which can become unlinked when a B. subtilis autolysin or egg white lysozyme is added to the culture medium.

Interleukin 3 augments the murine primary cytolytic T lymphocyte response to allogeneic tumor cells.

The primary anti-H-2k allospecific cytolytic T lymphocyte (CTL) response by BALB/c (H-2d) spleen cells in vitro to x-irradiated RDM4 (H-2k) tumor cells is weak. This response has been shown to be augmented by CTL helper factor (CHF), a factor present in supernatants of spleen cells cultured with Sendai virus (SC-CM). Conditioned medium from WEHI-3 cells (WEHI-CM) also contains activity that augments the BALB/c anti- RDM4 CTL response. Attempts to separate the CHF activity from interleukin 3 (IL 3), also present in WEHI-CM, were unsuccessful. Purified IL 3 was then tested, and was found to increase the BALB/c anti- RDM4 CTL response by five- to 10-fold. IL 3 is apparently the only material in WEHI-CM that is active in this assay. The response is apparently a classical CTL response because: 1) the effector cells are sensitive to monoclonal anti-Thy-1.2 antibody plus C; 2) the response is dependent on antigen stimulation, and it peaks on day 5 or 6 of culture; and 3) the effector cells are specific for H-2k targets. IL 3 must be added very early during the in vitro culture period for maximal augmentation of the response, consistent with possible action of IL 3 as a differentiation factor.

Time trends of smoking cessation: a micro-population computer simulation model.

The Micro-population model of Risk-group Dynamics (MRD) approaches smoking behavior at the level of the individual and integrates physiological and social factors to describe the evolution of behavior change in the population. MRD is innovative in several ways: (1) the model describes mathematically the interactions among these behavioral factors; (2) the model accounts for both the variability of these factors among different persons and the universality of basic rules describing these factors in all individuals; and (3) the model can be applied to various types of populations and a wide range of intervention strategies. MRD combines the physiological, psychological and social determinants into a hazard function for relapse to smoking. This hazard function is then organized into a three term expression incorporating: a baseline hazard characteristic to each individual, a decreasing term for the diminishing aspect of the initial hazard and an effect of external interventions. The model gives promising results when applied to the Multiple Risk Factors Intervention Trial (MRFIT) data using the assumptions of a Weibull distribution for the baseline hazard, a negative exponential for the decrease in the initial hazard and a constant intensity for the external intervention.

Essential genes in the metB-malB region of Escherichia coli K-12.

We isolated 25 independent mutants that are deficient in essential genes located in the metB-malB region of the Escherichia coli chromosome. The mutations were mapped within this region by using several F' factors and were also classified into 11 cistrons by complementation testing. There is clustering of mutations in essential genes within the metB-malB region.

Identification of an isolated protein essential for peptidoglycan synthesis as the N-acetylglucosaminyltransferase.

We have identified a protein extractable from Bacillus megaterium membranes by LiCl as the enzyme in peptidoglycan synthesis which catalyzes the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine to N-acetyl-D-muramyl-L-analyl-D-gamma-glutamyl-meso-diaminopimelyl-D-alanyl-D-alanine-P-P-lipid. This identification demonstrates the isolation and characterization of a membrane-associated enzyme involved in a complex series of reactions without the ready availability of a substrate for the enzyme.

Purification and properties of a protein factor stimulating peptidoglycan synthesis in toluene- and Licl-treated Bacillus megaterium cells.

A protein factor, called PG-I, can be solubilized from toluene-treated Bacillus megaterium cells by LiCl extraction. After LiCl extraction, peptidoglycan synthesis by the toluene-treated cells is decreased. Protein PG-I can be added back to the extracted cells to stimulate peptidoglycan synthesis. This factor has now been purified 124-fold. It has a molecular weight of 42,000 as estimated by Sephadex gel filtration in the presence of 0.4 M KCl and 52,000 as determined by sodium dodecyl sulfate disc gel electrophoresis. Periodate-Schiff staining of the polyacrylamide gel indicates that factor PG-I is a glycoprotein. The reconstitution of LiCl-extracted cells requires Mg2+ with an apparent Km of 1.9 X 10(-3) M. The Mg2+ ions can be replaced by Ca2+ and by Mn2+ ions to some extent; Zn2+ and Cu2+ ions had no effect. The available data suggest that factor PG-I is essential for peptidoglycan synthesis and requires at least one thiol group for stimulatory activity.

Further characterization of a non-essential mutator gene in Escherichia coli K-12.

The properties of mutR, a mutator closely linked to thyA, have been further characterized. We have found that the mutator gene is carried on a specialized transducing phage (lambdapcI857 thyA) generated by the excision of lambdacI857 integrated at a secondary attachment site between lysA and thyA. We present three lines of evidence indicating that mutR is a nonessential gene. (i) Deletions of the mutator can be found amoung survivors of heat induction of lambdacI857 when the phage is integrated between lysA and thyA. (ii) Mutations in mutR can be induced with the frameshift mutagen ICR-191. (iii) An amber mutant in mutR has been found. Viable strains could be made by combining the mutator with polB, polA polR, ligts7, and uvrA mutations. The mutator was still able to increase the spontaneous mutation frequency in these genetic backgrounds. When the reversion patterns of a series of well-characterized trpA mutations were analyzed, the results suggested that mutR is more efficient at causing transitions than transversion mutations.

Optimization of simulation models with GADELO: a multi-population genetic algorithm.

In this paper, a new Genetic Algorithm based on the Dynamic Exploration of Local Optima (GADELO) was used to estimate the parameters of the MRD (Micro-population model of Risk-group Dynamics) micro-population model for smoking cessation by minimizing a deviation function between the model's predictions and the smoking cessation data of the Multiple Risk Factor Intervention Trial (MRFIT). The efficiency and accuracy of the GADELO estimations were consistently superior to those obtained using the standard genetic algorithm or the simplex algorithm of Nelder-Mead.