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Biomedical subjects

M M Azar

Publications and source records attributed to M M Azar.

At least 19 recordsLinked to original sources
PubMed1998

Bacteremia with esophageal dilation.

BACKGROUND: Antibiotic prophylaxis has been recommended for selected patients undergoing esophageal stricture dilation because of a reported high rate of bacteremia. The aim of this study was to determine the rate of bacteremia after esophageal dilatation in a large series and the source of the organisms recovered. METHODS: Blood cultures and oral temperatures were obtained before esophageal dilation and at 5 and 30 minutes after dilation. Dilators were cultured immediately before dilation. Procedural data collected included type of dilation, number of passes, and presence of malignancy. RESULTS: Of 100 procedures in 86 patients undergoing esophageal dilation, 22 (22%) were associated with a positive post-dilation blood culture. Bacteremia was more frequent with dilation of malignant strictures compared with benign strictures (9 of 17 [52.9%] vs. 13 of 83 [15.7%], respectively, p = 0.002) and with passage of multiple dilators compared with passage of a single dilator (16 of 46 [34.8%] versus 6 of 54 [11.1%], respectively, p = 0.007). Bacterial isolates from 22 positive blood cultures matched those from a dilator in only one episode (4.5%). CONCLUSION: The rate of bacteremia after esophageal dilation is 22% and is associated with dilation of malignant strictures or passage of multiple dilators. Organisms cultured from the blood are not transmitted from the dilator.

Bacteremia↗
PubMed1996

The viability of Mycobacterium tuberculosis in formalin-fixed pulmonary autopsy tissue: review of the literature and brief report.

Formalin is commonly thought to decrease the risk of Mycobacterium tuberculosis infection. However, the true disinfection efficacy of formalin for tissue infected with M tuberculosis is unclear. We reviewed all pertinent literature from 1900 until the present regarding the disinfection efficacy of formalin for tissue infected with M tuberculosis. We also retrospectively cultured five cases of M tuberculosis from formalin-fixed archival pulmonary tissue. All cultures from our archived tissue were negative. The literature review revealed limited and contradictory information concerning the viability of M tuberculosis in formalin-fixed human tissue. There are no studies which specifically address the viability of M tuberculosis in tissue exclusively fixed in 10% buffered formalin. The disinfection efficacy of formalin for tuberculosis infected tissue remains unclear. Larger, prospective studies using current methodologies are needed to establish guidelines to ensure the safety for those handling infected, fixed tissue.

Autopsy↗
PubMed1987

Nonresponsiveness to Mlsd in F1 hybrid mice carrying Mlsa and Mlsc genes.

Neither the biological function nor a basic understanding of the enigmatic chromosome 1-encoded Mls locus of the mouse has yet been uncovered despite extensive investigations. The present report is a continuation of our genetic analyses of the Mls locus in an attempt to better define the system. Data presented here indicate that in contrast to cells of mice expressing either the Mlsa or Mlsc allele which respond in mixed leukocyte reactions to cells expressing the Mlsd allelic products, cells from (Mlsa X Mlsc)F1-hybrid mice do not. In addition, the nonresponder phenotype appears to segregate as a single autosomal genetic system in backcross animals. These findings fail to support two recently advanced hypotheses: first, that the Mls locus is nonpolymorphic, or second, that the Mls locus controls differential expression of Ia antigenic determinants. Although the mechanism by which a (responder X responder) converts to a nonresponder remains unknown, three models involving gene complementation are discussed.

Animals↗
PubMed1985

Immune responses in vitro. XIII. MLR detectability of Mlsa-, Mlsb-, Mlsc-, and Mlsd-encoded products.

The Mls locus was originally defined to have four alleles; all controlled products that were detectable in MLR except b, which was described as being null. More recent evidence led other investigators to postulate that the Mls locus is nonpolymorphic, being composed of only the b null allele and a singly expressed allele previously ascribed to be the a and d alleles. Our results indicate that Mlsa and Mlsd control products that are antigenically distinct and, therefore, the products cannot be controlled by the same allele. In addition, the product of Mlsb was easily detectable by Mlsa and Mlsd responding cells and cannot be considered null. Alternative explanations are considered for these conflicting results.

Animals↗
PubMed1984

Immune responses in vitro, XIV. Undetectability of Mlsb- and Mlsc-encoded products on F1 cells possessing Mlsa or Mlsd.

The Mls locus was originally defined to have four alleles; three controlled products that were detectable in primary mixed leukocyte reactions (MLR), whereas one, b, was described as being null. Recently, other investigators postulated that the Mls locus is nonpolymorphic, being composed of the b null allele and of a singly expressed allele previously thought to be the a and d alleles. We previously reported that products controlled by Mlsa and Mlsd were antigenically distinct and therefore are not controlled by the same allele, and the product of Mlsb on cells of three different strains was easily detectable by Mlsa and Mlsd responding cells. Thus the b allele is not null. In the present report evidence is presented which indicates that both Mlsb and Mlsc encoded products were undetectable by MLR when in the presence of Mlsa or Mlsd. This was demonstrated by the inability of Mlsa/Mlsc and Mlsa/Mlsb F1 cells to stimulate Mlsa responding cells and Mlsd/Mlsc and Mlsd/Mlsb cells to stimulate Mlsd cells; the positive response of Mlsa/Mlsb and Mlsd/Mlsb F1-hybrid cells to Mlsb-encoded products; and the reactivity of Mlsa/Mlsc and Mlsd/Mlsc F1 hybrid cells to Mlsc-encoded determinants.

Alleles↗
PubMed1982

Immune responses in vitro. XII. Two independently segregating loci control Mis product(s).

Distribution analyses of Misa in (BALB/c x DBA/2)F2 animals indicate that two independently segregating loci control the expression of Misa products. The results were dependent upon the use of x-irradiated cells a the antigen in MLR. The use of non-x-irradiated antigen in the MLR led to results that were uninterpretable because both DBA/2 and (BALB/c x DBA/2)F1 cells responded to x-irradiated BALB/c cells. Even though DBA/2 cells did not respond to (BALB/c x DBA/2)F1 cells, their reactivity to BALB/c cells indicates that the Misb of BALB/c is not null.

Alleles↗
PubMed1980

An enzymatic approach to lipoprotein quantification.

Lipoprotein cholesterol levels were determined without ultracentrifugation by using modified enzymatic methods for cholesterol, high-density-lipoprotein (HDL) cholesterol, and triglyceride and the formula, low-density-lipoprotein (LDL) cholesterol = total cholesterol-HDL cholesterol-triglycerides/5. The methods for cholesterol and triglyceride determinations were standardized for accuracy and precision by the Center for Disease Control's Lipid Standardization Laboratory, which monitored this laboratory for 16 months. The lipoprotein cholesterol values obtained correlated well with lipoprotein cholesterol values determined at the Minnesota Lipid Research Clinic Laboratory using ultracentrifugation. LDL cholesterol determined at the Minneapolis Veterans Administration Hospital Laboratories (Y axis) produced a curve with an intercept of 9.38 mg/dl, a slope of .977, standard error of the estimate (Sy.x) of 8.8 mg/dl, and a correlation coefficient (r) of .983 (n = 32). HDL cholesterol was Y = 0.998 X + .89 mg/dl, Sy.x = 1.6 mg/dl (r = .984, n = 53), and very-low-density-lipoprotein (VLDL) cholesterol was Y = 1.010 X -1.32 mg/dl, Sy.x = 1.3 mg/dl (r = .996, n = 54).

Cholesterol↗
PubMed1979

Inheritance of tolerance susceptibility to human gamma-globulin in congenic mice.

The genetic control of susceptibility to tolerance induction with human gamma-globulin (HGG) was studied by using H-2 congenic mice. Strains tested that were congenic with C57BL/10Sn were completely tolerized by 1.0 mg deaggregated HGG. In contrast A/Sn mice showed full tolerance whereas A.SW mice were only intermediately tolerant. It was further shown that (B10 X SJL)F1 mice could be rendered tolerant but (B10.S X SJL)F1 mice could not. These data indicate a role for H-2 linked genes in control of tolerance susceptibility. Results obtained with the progeny of (B10.S X SJL)F1 backcrossed to B10.S indicate that two non-H-2 linked genes are involved in control of tolerance induction. Preliminary mapping studies show the H-2 gene located to the left of the IC subregion. These results confirm our previous finding that both H-2 and non-H-2 genes control susceptibility of adult mice to tolerance induction with HGG.

Animals↗
PubMed1978

An enzymatic triglyceride method that is suitable for long-term population studies.

An enzymatic triglyceride method has been shown to be a suitable alternative to the Lipid Research Clinics' extraction/fluorometry method in long-term population studies. Correlation of results obtained with this method by this laboratory (y-axis) and by the Minneapolis Lipid Research Clinic Laboratory (x-axis) during a nine-week standardization period produced a curve with an intercept of -72 mg/liter, a slope of 1.019, and a correlation coefficient of r=0.996 (n=47). During this standardization period certain methodological problems were observed and corrected. An increase in background in certain clinical specimens, caused by spontaneous degradation of NADH, was observed, accurately measured, and taken into account when appropriate.

Glycerol Kinase↗
PubMed1978

Genetic control of tolerance induction to human gamma-globulin in mice.

Susceptibility to tolerance induction with monomeric human gamma-globulin (HGG) was tested in different inbred strains of mice. The results indicated a differential tolerance susceptibility among the strains and that the basis for the variation is genetic in nature. By using a protocol that permits genetic analysis, F1, F2, and backcross generations of the parental strains SJL/J and C3H/Bi were examined. A multigenic control model by H-2-linked and non-H-2-linked genes showing Mendelian autosomal inheritance is proposed.

Animals↗
PubMed1977

Comparison of murine delayed hypersensitivity reactions elicited with particle-associated versus soluble human gamma-globulin.

Footpad reactions elicited in DHS mice using human gamma-globulin (HGG)-coated polystyrene latex particles and soluble HGG (sHGG) were compared. Both the magnitude and the persistence of DHS lesions produced by HGG-latex were considerably greater; at 24, 48 and 72 h after challenge, the level of reactivity induced by HGG-latex was 24, 41 and 71% higher, respectively, than those elicited with sHGG. Early nonspecific swelling following injection of HGG-latex in footpads of normal mice was negligible by 24 h, whereas Arthus-responsive animals did not return to control levels until 48 h. The possible advantages and limitations of using particle-associated protein to elicit DHS reactions are discussed.

Animals↗