A prospective study of tobacco use and multiple myeloma: evidence against an association

The relationship between the use of cigarettes and other tobacco products and the risk of multiple myeloma was examined in a cohort of nearly 250,000 American veterans followed prospectively for 26 years. Compared with men who had never used tobacco, the risk of death from myeloma was not increased among current (relative risk [RR]=0.9, 95 percent confidence interval [CI]=0.8–1.2) or former (RR=1.0, CI=0.8–1.3) cigarette smokers, nor among users of chewing tobacco or snuff (RR=1.0, CI=0.4–2.3). Risk was only slightly and nonsignificantly increased among pipe or cigar smokers (RR=1.2, CI=0.9–1.5). There was no indication of increasing risk with amount of tobacco used or earlier age at first use. With over 90 percent power to detect a 30 percent increased risk of this tumor occuring among current cigarette smokers, this study provides the strongest evidence to date against an association of cigarette smoking with multiple myeloma.Epidemiology and Biometry Program, Division of Cancer Etiology, National Cancer Institute. Westat, Inc. Rockville, MD. National Cancer Institute, 6130 Executive Blvd, Room 418, Rockville, MD 20892, USA.     

Development of a reconstructed human skin model for angiogenesis

We have previously shown that reconstructed human skin engineered from autologous keratinocytes, fibroblasts, and sterilized donor allodermis stimulates angiogenesis within 5-7 days when placed on well-vascularized wound beds in nude mice. When this reconstructed skin was used clinically in more demanding wound beds, some grafts were lost, possibly due to delayed vascularization. As this reconstructed skin lacks any endothelial cells, our aim in this study was to develop an angiogenic reconstructed skin model in which to explore strategies to improve angiogenesis both in vitro and in vivo. We report that culture of small-vessel human dermal microvascular endothelial cells (HuDMECs) was achieved using magnetic beads coated with an antibody to platelet cell adhesion molecule as a means of purifying the culture. Keratinocytes, fibroblasts, and HuDMECs could be cultured from the same skin biopsy. Initial studies culturing HuDMECs and other sources of endothelial cells with the tissue-engineered skin showed that these cells were capable of slowly entering the dermis under standard culture conditions in vitro. In conclusion, this provides us with a model in which to explore strategies for improving angiogenesis in vitro and also establishes the culture methodologies for the production of reconstructed skin containing autologous keratinocytes, fibroblasts, and endothelial cells.     

Short-Term Malaria Reduction by Single-Dose Azithromycin during Mass Drug Administration for Trachoma,Tanzania

Single-dose mass drug administration of azithromycin (AZT) is underway to eliminate trachoma worldwide. Studies in Ethiopia showed a reduction in all-cause childhood deaths after administration. To examine the effect of single-dose AZ MDA on prevalent malaria infections in a large prospective cohort of children and parents in Dodoma Province, Tanzania, we quantified the temporal prevalence of malaria parasitemia by real-time PCR for 6 months after single-dose AZT. In the first month after treatment but not in subsequent months, Plasmodium falciparum infections were reduced by 73% (95% CI 43%–89%) in treatment versus control villages and differences remained significant (p = 0.00497) in multivariate models with village-level random effects. Genetic sequencing of P. falciparum ribosomal L4 protein showed no mutations associated with AZT resistance. AZT mass drug administration caused a transient, 1-month antimalarial effect without selecting for P. falciparum ribosomal L4 resistance mutations in a region with a 10-year history of treating trachoma with this drug.     

Acute and chronic liver toxicity resulting from exposure to chlorinated naphthalenes at a cable manufacturing plant during World War II

Historical records were used to reconstruct an outbreak of chloracne and acute liver toxicity due to chlorinated napthalene exposure at a New York State plant which manufactured “Navy cables” during World War II. A cohort mortality study was conducted of the population (n = 9.028) employed at the plant from 1940 to 1944. Vital status followed through December 31, 1985. The study found an excess of deaths from cirrhosis of the liver [observed (OBS) = 150; standardized mortality ratio (SMR) = 1.84; 95% confidence interval (CI) = 1.56-2.16]; cirrhosis deaths were elevated to a similar degree in the 460 individuals who had chloracne (OBS = 8; SMR = 1.51; CI = 0.65-2.98). The SMR for “non-alcoholic cirrhosis” (OBS = 83; SMR = 1.67; CI = 1.33-2.07) was similar to the SMR for “alcoholic cirrhosis” (OBS = 59; SMR = 1.96; CI = 1.49-2.53). There was no evidence for increased alcoholism in the overall cohort based on mortality from alcohol-related causes of death other than cirrhosis (SMR for esophageal cancel = 1.01 and for deaths from alcoholism = 0.99). We conclude that the excess mortality from cirrhosis of the liver observed in this cohort is due to the chronic effect of chlorinated naphthalene exposure. © 1996 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

MicroRNA-27a/b regulates cellular cholesterol efflux,influx and esterification/hydrolysis in THP-1 macrophages

Rationale

Macrophage cholesterol homeostasis maintenance is the result of a balance between influx, endogenous synthesis, esterification/hydrolysis and efflux. Excessive accumulation of cholesterol leads to foam cell formation, which is the major pathology of atherosclerosis. Previous studies have shown that miR-27 (miR-27a and miR-27b) may play a key role in the progression of atherosclerosis.

Objective

We set out to investigate the molecular mechanisms of miR-27a/b in intracellular cholesterol homeostasis.

Methods and results

In the present study, our results have shown that the miR-27 family is highly conserved during evolution, present in mammals and directly targets the 3′ UTR of ABCA1, LPL, and ACAT1. apoA1, ABCG1 and SR-B1 lacking miR-27 bind sites should not be influenced by miR-27 directly. miR-27a and miR-27b directly regulated the expression of endogenous ABCA1 in different cells. Treatment with miR-27a and miR-27b mimics reduced apoA1-mediated cholesterol efflux by 33.08% and 44.61% in THP-1 cells, respectively. miR-27a/b also regulated HDL-mediated cholesterol efflux in THP-1 macrophages and affected the expression of apoA1 in HepG2 cells. However, miR-27a/b had no effect on total cellular cholesterol accumulation, but regulated the levels of cellular free cholesterol and cholesterol ester. We further found that miR-27a/b regulated the expression of LPL and CD36, and then affected the ability of THP-1 macrophages to uptake Dil-oxLDL. Finally, we identified that miR-27a/b regulated cholesterol ester formation by targeting ACAT1 in THP-1 macrophages.

Conclusion

These findings indicate that miR-27a/b affects the efflux, influx, esterification and hydrolysis of cellular cholesterol by regulating the expression of ABCA1, apoA1, LPL, CD36 and ACAT1.     

Occupation and risk of non-Hodgkin's lymphoma and chronic lymphocytic leukemia

To investigate the association between occupation and the risk of non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL), and to test whether the associations may vary by histological type of NHL, we analyzed data from two population-based, case-control studies of NHL performed in Kansas and Nebraska. A total of 555 incident NHL cases, 56 CLL cases, and 2380 population-based controls were included in the analysis. Information on occupation and other confounding factors was collected through telephone interviews. Study pathologists reviewed slides of tumor tissues in all cases. In men, we found an increased risk of NHL and CLL for those working in agricultural, forestry, and logging industries (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.2 to 2.1). The OR was 1.9 (95% CI, 1.4 to 2.6) for those producing crops. An increased risk was also observed for industries involving metalworking machinery and equipment (OR, 8.4; 95% CI, 1.4 to 50.6), motor vehicles and motor vehicle equipment (OR, 4.2; 95% CI, 1.3 to 13.9), and telephone communications (OR, 3.1; 95% CI, 1.2 to 8.0), and for teachers (OR, 2.5; 95% CI, 1.0 to 6.5), farmers (OR, 2.0; 95% CI, 1.5 to 2.8), and welders and solderers (OR, 2.9; 95% CI, 1.2 to 6.9). The risks for these associations increased by duration of employment and seem to vary by histological type. Work in the printing and publishing industry was also associated with an increased risk of NHL among women. These data suggest that the workers employed in these industries or occupations experienced an increased risk of NHL and CLL, and the risks associated with these industries or occupations may vary by histological type of NHL.