Risk of cataract for people with tuberculosis: results from a population-based cohort study.

BACKGROUND: Tuberculosis (TB) is an infectious disease involving multiple organs, including the eyes. We examined the risk of cataract among patients with TB using population data. METHOD: Using data from the National Health Insurance (NHI) system of Taiwan, we established a TB cohort with 6994 patients newly diagnosed between 2000 and 2010. For each TB patient, four subjects without TB were randomly selected for the non-TB cohort, frequency matched by age, sex and diagnosis years. The incidence of cataract was measured by the end of 2011. The hazard ratio (HR) of cataract was estimated using Cox proportional hazards regression analysis. RESULTS: The overall incidence rate of cataract was 21% greater in the TB cohort than in the non-TB cohort (22.9 vs. 18.8/1000 person-years, P < 0.001), with an adjusted HR (aHR) of 1.26 (95%CI 1.16-1.37). Cataract incidence increased with age, and was higher in men than women and much higher for those with comorbidity. The hazard of cataract was higher in the first 6 months after TB diagnosis. CONCLUSION: TB patients are at elevated risk of developing cataract. Although the incidence decreased with time, the aHR remains statistically significant through the follow-up years.

CCAAT/enhancer binding protein beta regulates expression of the cystatin-related epididymal spermatogenic (Cres) gene.

The CRES protein is a member of the cystatin superfamily of cysteine protease inhibitors with restricted expression in stage-specific germ cells, proximal caput epididymidis, and anterior pituitary gonadotroph cells. To elucidate the molecular mechanisms regulating the highly restricted expression of the cres gene, we have sequenced 1.6 kilobases of mouse cres 5' flanking sequence and performed studies to examine the cres gene promoter. Two putative CCAAT/enhancer binding protein (C/EBP) transcription factor binding motifs exist within the first 135 base pairs of cres promoter. Furthermore, our studies demonstrate that cres mRNA levels are dramatically reduced in the epididymides of C/EBP beta-deficient mice. These data suggest that the C/EBP family of transcription factors, in particular C/EBP beta, plays a role in the regulation of cres gene expression. In support of this finding, Northern blot analysis showed that C/EBP beta is the predominant C/EBP family member expressed in the L beta T2 gonadotroph cell line and the proximal caput epididymidis. Also, gel shift and supershift assays demonstrated that C/EBP beta protein in nuclear extracts from L beta T2 gonadotroph cells and epididymal cells bound to the two C/EBP sites in the cres promoter. Finally, to test the in vivo function of the C/EBP sites in cres gene expression, transfection studies were performed in L beta T2 gonadotroph cells and two heterologous cell systems. These experiments showed a significant reduction of cres transactivation when either C/EBP sites were mutated, and no transC/EBP activation of the cres promoter when both C/EBP sites were mutated. Taken together, these studies demonstrate that the C/EBP beta transcription factor is necessary for high levels of cres gene expression in the proximal caput epididymidis and anterior pituitary gonadotroph cells.

B-Myc, a proximal caput epididymal protein, is dependent on androgens and testicular factors for expression.

The myc family of transcriptional regulators carries out critical roles in the control of cellular proliferation, differentiation, apoptosis, and tumorigenesis. The B-myc gene is a recently identified myc family member that has not been well characterized. Previously, we have shown that B-Myc inhibits the ability of c-Myc to transform cells and can inhibit cellular proliferation. Because B-myc is primarily expressed in hormonally regulated tissues with predominant expression in the epididymis, we examined in greater detail B-myc expression in the epididymis to ultimately understand potential roles B-myc may play in this and other hormonally regulated tissues. Herein we demonstrate that, in contrast to c-myc, B-myc mRNA and protein expression are highly regionalized with expression predominantly in the proximal caput epididymal region. Furthermore, in situ and immunohistochemical analyses show that within the epididymis B-myc mRNA and protein are specifically expressed by the epithelial cells and that B-Myc protein is localized to both the nuclear and cytosolic compartments. Castration and hormone replacement studies further show that expression of the B-myc mRNA is highly dependent on the presence of androgens and testicular factors. Finally, mRNA turnover studies demonstrate that the B-myc mRNA is relatively unstable with a half-life of 3.5 h. Taken together, the highly restricted and regulated expression of the B-myc gene suggests it may play important regulatory roles in the epididymis and perhaps other hormonally regulated tissues.

Structure, alternative splicing and chromosomal localization of the cystatin-related epididymal spermatogenic gene.

The cystatin superfamily of cysteine protease inhibitors consists of three major families, including the stefins, cystatins and kininogens. However, the recent identification of several genes that possess sequence similarity with the cystatins but have different gene or protein structures indicates that several new cystatin families or subgroups of families might exist. We previously identified the cystatin-related epididymal spermatogenic (Cres) gene, which is related to the family 2 cystatins but exhibits highly tissue-specific expression in the reproductive tract. In the studies presented here, an analysis of gene structure as well as chromosomal mapping studies suggest that the Cres gene might represent a new subgroup within the family 2 cystatins. Although the Cres gene possesses an additional exon encoding 5' untranslated sequences, its coding exons are similar in size to the three coding exons of the cystatin family 2 genes, and the Cres exon/intron splice junctions occur in identical locations as in the cystatin C gene. Furthermore, chromosomal mapping studies show that the Cres gene co-segregates with the cystatin C gene on mouse chromosome 2. Similar to the cystatin family 2 proteins, the Cres protein possesses the type A and B disulphide loops that are necessary for cystatin folding. Interestingly, Cres protein also possesses half of a type C disulphide loop. Although probably related to the cystatin genes, the Cres gene is distinct in that its promoter contains consensus motifs typical of regulated genes. Finally, reverse transcriptase-mediated PCR studies and the identification of new Cres cDNA clones indicate that the Cres mRNA is alternatively spliced, resulting in two Cres mRNAs that might be involved in the regulation of Cres function.

ADAM7, a member of the ADAM (a disintegrin and metalloprotease) gene family is specifically expressed in the mouse anterior pituitary and epididymis.

The maturation of spermatozoa in the epididymis is a complex process that requires the active involvement of the epididymal epithelium. The primary focus toward elucidating the role of the epididymis in the maturation process has been the study of epididymal secretory proteins and their interaction with spermatozoa. To date there is a paucity of information regarding epididymal epithelial cell surface proteins, which may also play important roles in epididymal function. Through a subtractive hybridization approach to identify genes specifically expressed in the caput epididymidis, the mouse homologue of a member of the ADAM (a disintegrin and metalloprotease) family of proteins was identified. This rapidly growing gene family encodes cell surface proteins that possess putative adhesion and protease domains. Northern blot analyses demonstrated that the mouse ADAM gene, termed ADAM7, is expressed in the caput region of the epididymis and in the anterior pituitary gonadotropes with no detectable expression in the twenty-six other tissues examined. Furthermore, in situ hybridization experiments revealed that the ADAM7 messenger RNA (mRNA) exhibited an apical localization within the proximal caput epididymal epithelium that may correlate with an unusual sparsely granulated endoplasmic reticulum uniquely present in the proximal region of the epididymidis and to which no known function has been ascribed. Hormonal, surgical, and genetic strategies demonstrated that ADAM7 gene expression requires, in a region-dependent manner, androgens as well as testicular factors for expression. Interestingly, the apical localization of ADAM7 mRNA is dependent upon an intact testis, because in situ hybridization analyses of the proximal caput epididymidis from a testosterone maintained castrate mouse did not show the apical localization of ADAM7 mRNA. Finally, chromosomal mapping demonstrated that the ADAM7 gene maps to the central region of mouse Chromosome 14, approximately 4-5 cM distal from the fertilin beta locus, which encodes another reproductive-specific ADAM protein.

The toxicities of native and modified hemoglobins.

Recent research on the potential use of hemoglobin derivatives as a blood substitute has revealed that the administration of large quantities of free hemoglobin into the circulation results in a variety of toxic side effects. Because it has been well established that hemoglobin, like myoglobin, has considerable pro-oxidant activity, a number of studies have appeared suggesting that the administered hemoglobins may catalyze various oxidative and peroxidative reactions, which in turn, would cause the observed pathologic conditions. This occurs as a result of the in vivo formation of highly oxidized forms of the native and modified hemoglobins. In addition, it has been proposed that considerable amounts of free hemin and iron may be generated as a result of the catabolism of the injected hemoglobin. Hemin is known to be very toxic when present in large amounts, and iron could catalyze the formation of hydroxyl radicals via Fenton-type reactions. Thus, the toxic activities of catabolic products of hemoglobin could also be involved in all or part of the observed side effects. The purpose of this review is to consider the conditions under which reactive species of hemoglobin may be formed in vivo, their potential reactivity, and whether their individual or combined oxidative activities could account for the biological damage that is observed in vivo following hemoglobin transfusions.

The cytotoxic activities of human hemoglobin and diaspirin crosslinked hemoglobin.

It is well known that hemoglobin (Hb) possesses many oxidative enzyme activities, including a pseudo-peroxidase activity. It has also been shown by many investigators that various peroxidases in the presence of hydrogen peroxide and a halide ion exert a potent cytotoxic activity toward various mammalian cell types. It has further been observed by various investigators that the administration of relatively large amounts of purified Hb or a Hb derivative to a host animal during resuscitation experiments leads to a number of unrelated types of tissue damage and cell damage in the host. The first objective of this investigation was to determine if the observed tissue and cell damage may be due to a cytotoxic activity that Hb may exert in vivo analogous to that of the peroxidases. We also showed some time ago that peroxidases are able to activate peritoneal macrophages to the cytocidal state. Hence, we also addressed the question whether or not Hb is able to activate macrophages in a similar manner. Our results were negative with regard to both questions. Further investigations indicated that, unlike the peroxidases, ferryl-Hb is unable to oxidize iodide to iodine at a measurable rate, which appears to be the reason for the lack of cytotoxic activity.