Transmission patterns of smallpox: systematic review of natural outbreaks in Europe and North America since World War II

BACKGROUND: Because smallpox (variola major) may be used as a biological weapon, we reviewed outbreaks in post-World War II Europe and North America in order to understand smallpox transmission patterns. METHODS: A systematic review was used to identify papers from the National Library of Medicine, Embase, Biosis, Cochrane Library, Defense Technical Information Center, WorldCat, and reference lists of included publications. Two authors reviewed selected papers for smallpox outbreaks. RESULTS: 51 relevant outbreaks were identified from 1,389 publications. The median for the effective first generation reproduction rate (initial R) was 2 (range 0–38). The majority outbreaks were small (less than 5 cases) and contained within one generation. Outbreaks with few hospitalized patients had low initial R values (median of 1) and were prolonged if not initially recognized (median of 3 generations); outbreaks with mostly hospitalized patients had higher initial R values (median 12) and were shorter (median of 3 generations). Index cases with an atypical presentation of smallpox were less likely to have been diagnosed with smallpox; outbreaks in which the index case was not correctly diagnosed were larger (median of 27.5 cases) and longer (median of 3 generations) compared to outbreaks in which the index case was correctly diagnosed (median of 3 cases and 1 generation). CONCLUSION: Patterns of spread during Smallpox outbreaks varied with circumstances, but early detection and implementation of control measures is a most important influence on the magnitude of outbreaks. The majority of outbreaks studied in Europe and North America were controlled within a few generations if detected early

Naturally Occurring Genetic Variants in Human Chromogranin A (CHGA) Associated with Hypertension as well as Hypertensive Renal Disease

Chromogranin A (CHGA) plays a fundamental role in the biogenesis of catecholamine secretory granules. Changes in storage and release of CHGA in clinical and experimental hypertension prompted us to study whether genetic variation at the CHGA locus might contribute to alterations in autonomic function, and hence hypertension and its target organ consequences such as hypertensive renal disease (nephrosclerosis). Systematic polymorphism discovery across the human CHGA locus revealed both common and unusual variants in both the open reading frame and such regulatory regions as the proximal promoter and 3′-UTR. In chromaffin cell-transfected CHGA 3′-UTR and promoter/luciferase reporter plasmids, the functional consequences of the regulatory/non-coding allelic variants were documented. Variants in both the proximal promoter and the 3′-UTR displayed statistical associations with hypertension. Genetic variation in the proximal CHGA promoter predicted glomerular filtration rate in healthy twins. However, for hypertensive renal damage, both end-stage renal disease and rate of progression of earlier disease were best predicted by variants in the 3′-UTR. Finally, mechanistic studies were undertaken initiated by the clue that CHGA promoter variation predicted circulating endothelin-1. In cultured endothelial cells, CHGA triggered co-release of not only the vasoconstrictor and pro-fibrotic endothelin-1, but also the pro-coagulant von Willebrand Factor and the pro-angiogenic angiopoietin-2. These findings, coupled with stimulation of endothelin-1 release from glomerular capillary endothelial cells by CHGA, suggest a plausible mechanism whereby genetic variation at the CHGA locus eventuates in alterations in human renal function. These results document the consequences of genetic variation at the CHGA locus for cardiorenal disease and suggest mechanisms whereby such variation achieves functional effects

Beneficial Effects of Soy Isoflavones on Blood Pressure and Lipid Profile in Indian Postmenopausal Women

Background: The studies have suggested that dietary isoflavones intake in postmenopausal women had protective role against cardiovascular disease (CVD). Objectives: This study ascertained the effect of isoflavone in the form of soyflour on lipid profiles and blood pressure (BP) in postmenopausal women diagnosed with medium risk of CVD. Materials and Methods: It was a 16-week placebo controlled trial that was conducted on 60 postmenopausal women aged 45–55 years. Participants in the treatment group were provided with 40 g soyflour/day for 16 weeks. The participants in the control group were asked not to change their usual dietary habits and lifestyles and were instructed to avoid taking soybean and soybean products. The changes in BP and blood lipid profile were measured at baseline and at the end of the study. Results: There were non-significant differences in any of the variables between two groups at baseline. Biochemical results indicated the beneficial effect of intervention in significantly reducing systolic (6.28%) and diastolic (4.73%) BP of the treatment group. It also exhibited an effective role in significantly (P < 0.05) reducing the serum cholesterol (17.29%), triglyceride (22.22%), low density lipoprotein (24.53%), very low density lipoprotein (22.21%), and significantly increasing the high density lipoprotein (13.55%) in the treatment group. Conclusion: The study indicates that daily administration of 40g soyflour for 16 weeks improved the BP and lipid profile of postmenopausal subjects

Identification of Amino Acid Residues of Anthrax Protective Antigen Involved in Binding with Lethal Factor

Protective antigen (PA) and lethal factor (LF) are the two components of anthrax lethal toxin. PA is responsible for the translocation of LF to the cytosol. The binding of LF to cell surface receptor-bound PA is a prerequisite for the formation of lethal toxin. It has been hypothesized that hydrophobic residues P184, L187, F202, L203, P205, I207, I210, W226, and F236 of domain 1b of PA play an important role in the binding of PA to LF. These residues are normally buried in the 83-kDA version of PA, PA83, as determined by the crystal structure of PA. However, they become exposed due to the conformational change brought about by the cleavage of PA83 to PA63 by a cell surface protease. Mutation of the above-mentioned residues to alanine resulted in mutant proteins that were able to bind to the cell surface receptors and also to be specifically cleaved by the cellular proteases. All the mutant proteins except the F202A, L203A, P205A, and I207A mutants were able to bind to LF and were also toxic to macrophage cells in combination with LF. It was concluded that residues 202, 203, 205, and 207 of PA are essential for the binding of LF to PA

Involvement of residues 147VYYEIGK153 in binding of lethal factor to protective antigen of Bacillus anthracis

Anthrax toxin is a complex of protective antigen (PA, 735 aa), lethal factor (LF, 776 aa), and edema factor (EF, 767 aa). PA binds to cell surface receptors and is cleaved by cell surface proteases into PA<SUB>63</SUB>, while LF and EF compete for binding to PA<SUB>63</SUB>. The PA<SUB>63</SUB>-LF/EF complex is internalized into the cytosol and causes different pathogenic responses in animals and cultured cells. 1-300 amino acid residues of LF have been viewed as the region responsible for the high affinity binding of LF to PA. Amino acid analysis of LF and EF revealed a common stretch of 7 amino acids (147VYYEIGK153). In the present study, each amino acid of this stretch was replaced by alanine at a time. Y148A, Y149A, I151A, and K153A mutants were found to be deficient in their ability to lyse J774A.1 cells and their binding ability to PA<SUB>63</SUB> was drastically reduced. We propose that these four amino acids play a crucial role in the process of binding of LF to PA<SUB>63</SUB>

Asp 187 and Phe 190 residues in lethal factor are required for the expression of anthrax lethal toxin activity

Anthrax toxin consists of three proteins, protective antigen, lethal factor, and edema factor. Protective antigen translocates lethal factor and edema factor to the cytosol of mammalian cells. The amino-termini of lethal factor and edema factor have several homologous stretches. These regions are presumably involved in binding to protective antigen. In the present study we have determined the role of one such homologous stretch in lethal factor. Residues 187AspLeuLeuPhe190 were replaced by alanine. Asp187Ala and Phe190Ala were found to be non-toxic in combination with protective antigen. Their protective antigen-binding ability was drastically reduced. We propose that Asp187 and Phe190 are crucial for the expression of anthrax lethal toxin activity

Trp 346 and Leu 352 residues in protective antigen are required for the expression of anthrax lethal toxin activity

The three separate proteins that make up anthrax toxin-protective antigen (PA), edema factor (EF) and lethal factor (LF) act in binary combinations to produce two distinct reactions in experimental animals: edema (PA+EF) and death (PA+LF). PA is believed to interact with a membrane receptor and, after proteolytic processing, to mediate endocytosis and subsequent translocation of EF or LF into the cytosol. Residues W346, M350, and L352 in loop 3 of domain 2 have been implicated to induce a conformational change when the pH is lowered from 7.4 to 6.5. Modification of the residues Trp (346), Met (350), and Leu (352) to alanine individually and all the three residues together to alanine residues resulted in the loss of cytotoxic activity in combination with LF. The mutant proteins were able to bind to the cell surface receptor, become cleaved by trypsin, bind LF, and oligomerize. These residues might play an important role in the membrane insertion of PA and/or translocation of LF/EF into the cytosol

Constitutive expression of protective antigen gene of Bacillus anthracis in Escherichia coli

The fatal bacterial infection caused by inhalation of the Bacillus anthracis spores results from the synthesis of protein toxins-protective antigen (PA), lethal factor (LF), and edema factor (EF)-by the bacterium. PA is the target-cell binding protein and is common to the two effector molecules, LF and EF, which exert their toxic effects once they are translocated to the cytosol by PA. PA is the major component of vaccines against anthrax since it confers protective immunity. The large-scale production of recombinant protein-based anthrax vaccines requires overexpression of the PA protein. We have constitutively expressed the protective antigen protein in E. coli DH5a strain. We have found no increase in degradation of PA when the protein is constitutively expressed and no plasmid instability was observed inside the expressing cells. We have also scaled up the expression by bioprocess optimization using batch culture technique in a fermentor. The protein was purified using metal-chelate affinity chromatography. Approximately 125 mg of recombinant protective antigen (rPA) protein was obtained per liter of batch culture. It was found to be biologically and functionally fully active in comparison to PA protein from Bacillus anthracis. This is the first report of constitutive overexpression of protective antigen gene in E. coli

A Comparison of Four-Year Health Outcomes following Combat Amputation and Limb Salvage.

Little research has described the long-term health outcomes of patients who had combat-related amputations or leg-threatening injuries. We conducted retrospective analysis of Department of Defense and Department of Veterans Affairs health data for lower extremity combat-injured patients with (1) unilateral amputation within 90 days postinjury (early amputation, n = 440), (2) unilateral amputation more than 90 days postinjury (late amputation, n = 78), or (3) leg-threatening injuries without amputation (limb salvage, n = 107). Patient medical records were analyzed for four years postinjury. After adjusting for group differences, early amputation was generally associated with a lower or similar prevalence for adverse physical and psychological diagnoses (e.g., pain, osteoarthritis, posttraumatic stress disorder) versus late amputation and/or limb salvage. By contrast, early amputation was associated with an increased likelihood of osteoporosis during the first year postinjury. The prevalence of posttraumatic stress disorder increased for all patient groups over four years postinjury, particularly in the second year. The different clinical outcomes among combat extremity injured patients treated with early amputation, late amputation, or limb salvage highlight their different healthcare requirements. These findings can inform and optimize the specific treatment pathways that address the physical and psychological healthcare needs of such patients over time