Evaluation of alpha-defensins as a marker of severity in chronic obstructive pulmonary disease.

BACKGROUND: Defensins are key effector molecules of innate immunity that can contribute towards the diagnosis and monitoring of chronic obstructive pulmonary disease (COPD). The present study was conducted to investigate the role of alpha-defensins in patients with COPD by quantifying serum and sputum samples. METHODS: A total of 180 patients were enrolled and divided into four groups, and sputum and serum values of alpha-defensins were assessed. The sensitivity, specificity, and accuracy of sputum alpha-defensin as a diagnostic biomarker were evaluated to assess its utility in diagnosing COPD. RESULTS: The mean value of sputum alpha-defensins was found to be statistically significant amongst the four groups (P < 0.001). The highest levels were found in subjects with AECOPD (385.76 ± 116.62 ng/mL). Sputum alpha-defensins were found to be negatively correlated with FEV 1 values (rho = -0.31, P < 0.001). CONCLUSION: Sputum alpha-defensins can be used as a potential marker for predicting acute exacerbation of COPD. In addition, they could serve as an indicator of disease severity in COPD patients.

How 'eye' helped in von Hippel-Lindau syndrome.

BACKGROUND: Von Hippel-Lindau syndrome is a rare autosomal dominantly inherited multisystemic oncologic syndrome, presenting predominantly with angiomatosis in embryologically similar neurologic tissue such as retina, cerebellum and adrenals. Retinal hemangioblastomas are the hallmark ophthalmic finding. In this case report, we describe the importance of timely diagnosis, thorough systemic examination and treatment of bilaterally asymmetrical retinal hemangioblastomas in a young adult male. CASE PRESENTATION: A 31-year-old male presented with painless diminution of vision in both eyes, associated with eyestrain and headache. Multiple asymmetric retinal lesions and dilated feeder vessels were noted on ophthalmoscopic examination and confirmed by fluorescein angiography to be retinal hemangioblastomas. Comprehensive systemic examination revealed cerebellar hemangioblastomas and multiple pancreatic and renal cysts. Treatment of retinal lesions was done by combination therapy of argon laser photocoagulation and cryopexy, which lead to a good visual outcome. Subsequently, neurosurgical resection of cerebellar hemangioblastoma proved to be lifesaving for the patient. CONCLUSION: RHBs are the earliest, easiest and the most frequently detected manifestation of VHL. Identification of ocular manifestations play a pivotal role in early diagnosis and timely intervention in VHL syndrome, thereby significantly reducing associated morbidity and mortality. Therefore, an ophthalmologist's role is crucial in the management of these potentially deadly tumours.

Potent and Broad Inhibition of HIV-1 by a Peptide from the gp41 Heptad Repeat-2 Domain Conjugated to the CXCR4 Amino Terminus.

HIV-1 entry can be inhibited by soluble peptides from the gp41 heptad repeat-2 (HR2) domain that interfere with formation of the 6-helix bundle during fusion. Inhibition has also been seen when these peptides are conjugated to anchoring molecules and over-expressed on the cell surface. We hypothesized that potent anti-HIV activity could be achieved if a 34 amino acid peptide from HR2 (C34) were brought to the site of virus-cell interactions by conjugation to the amino termini of HIV-1 coreceptors CCR5 or CXCR4. C34-conjugated coreceptors were expressed on the surface of T cell lines and primary CD4 T cells, retained the ability to mediate chemotaxis in response to cognate chemokines, and were highly resistant to HIV-1 utilization for entry. Notably, C34-conjugated CCR5 and CXCR4 each exhibited potent and broad inhibition of HIV-1 isolates from diverse clades irrespective of tropism (i.e., each could inhibit R5, X4 and dual-tropic isolates). This inhibition was highly specific and dependent on positioning of the peptide, as HIV-1 infection was poorly inhibited when C34 was conjugated to the amino terminus of CD4. C34-conjugated coreceptors could also inhibit HIV-1 isolates that were resistant to the soluble HR2 peptide inhibitor, enfuvirtide. When introduced into primary cells, CD4 T cells expressing C34-conjugated coreceptors exhibited physiologic responses to T cell activation while inhibiting diverse HIV-1 isolates, and cells containing C34-conjugated CXCR4 expanded during HIV-1 infection in vitro and in a humanized mouse model. Notably, the C34-conjugated peptide exerted greater HIV-1 inhibition when conjugated to CXCR4 than to CCR5. Thus, antiviral effects of HR2 peptides can be specifically directed to the site of viral entry where they provide potent and broad inhibition of HIV-1. This approach to engineer HIV-1 resistance in functional CD4 T cells may provide a novel cell-based therapeutic for controlling HIV infection in humans.

Membrane stresses induced by overproduction of free fatty acids in Escherichia coli.

Microbially produced fatty acids are potential precursors to high-energy-density biofuels, including alkanes and alkyl ethyl esters, by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversion of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs in Escherichia coli have achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain of E. coli that overproduces medium-chain-length FFAs was compared to an engineered control strain. By early stationary phase, an 85% reduction in viable cell counts and exacerbated loss of inner membrane integrity were observed in the FFA-overproducing strain. These effects were enhanced in strains endogenously producing FFAs compared to strains exposed to exogenously fed FFAs. Under two sets of cultivation conditions, long-chain unsaturated fatty acid content greatly increased, and the expression of genes and proteins required for unsaturated fatty acid biosynthesis were significantly decreased. Membrane stresses were further implicated by increased expression of genes and proteins of the phage shock response, the MarA/Rob/SoxS regulon, and the nuo and cyo operons of aerobic respiration. Gene deletion studies confirmed the importance of the phage shock proteins and Rob for maintaining cell viability; however, little to no change in FFA titer was observed after 24 h of cultivation. The results of this study serve as a baseline for future targeted attempts to improve FFA yields and titers in E. coli.

Wispy, the Drosophila homolog of GLD-2, is required during oogenesis and egg activation.

Egg activation is the process that modifies mature, arrested oocytes so that embryo development can proceed. One key aspect of egg activation is the cytoplasmic polyadenylation of certain maternal mRNAs to permit or enhance their translation. wispy (wisp) maternal-effect mutations in Drosophila block development during the egg-to-embryo transition. We show here that the wisp gene encodes a member of the GLD-2 family of cytoplasmic poly(A) polymerases (PAPs). The WISP protein is required for poly(A) tail elongation of bicoid, Toll, and torso mRNAs upon egg activation. In Drosophila, WISP and Smaug (SMG) have previously been reported to be required to trigger the destabilization of maternal mRNAs during egg activation. SMG is the major regulator of this activity. We report here that SMG is still translated in activated eggs from wisp mutant mothers, indicating that WISP does not regulate mRNA stability by controlling the translation of smg mRNA. We have also analyzed in detail the very early developmental arrest associated with wisp mutations. Pronuclear migration does not occur in activated eggs laid by wisp mutant females. Finally, we find that WISP function is also needed during oogenesis to regulate the poly(A) tail length of dmos during oocyte maturation and to maintain a high level of active (phospho-) mitogen-activated protein kinases (MAPKs).