Erythema Ab Igne: A Rare Presentation of Toasted Skin Syndrome With the Use of a Space Heater.

Erythema ab igne, also known as toasted skin syndrome, is an acquired asymmetric hyperpigmented dermatosis that is caused by repeated exposure to moderate heat or infrared radiation. Hyperpigmentation is caused by the degeneration of elastic fibers and basal cells resulting in the release of melanin. Historically found in bakers and industrial workers, this condition has recently resurfaced in medical literature with the use of novel heat sources such as laptops and heated car seats. While this condition can resolve spontaneously after removal of heat exposure, delay in diagnosis and persistent exposure can lead to permanent pigmentation or progression to Merkel cell carcinoma, basal cell carcinoma, and squamous cell carcinoma.

Insecticidal activity of a basement membrane-degrading protease against Heliothis virescens (Fabricius) and Acyrthosiphon pisum (Harris).

ScathL is a cathepsin L-like cysteine protease derived from the flesh fly Sarcophaga peregrina that functions in basement membrane (BM) remodeling during insect development. A recombinant baculovirus expressing ScathL (AcMLF9.ScathL) kills larvae of the tobacco budworm, Heliothis virescens, significantly faster than the wild-type virus. Here, we show that the occurrence of larval melanization prior to death was closely associated with the onset of high cysteine protease activity of ScathL in the hemolymph of fifth instars infected with AcMLF9.ScathL, but not with AcMLF9.ScathL.C146A, a recombinant baculovirus expressing a catalytic site mutant of ScathL. Fragmented fat body, ruptured gut and malpighian tubules, and melanized tracheae were observed in AcMLF9.ScathL-infected larvae. Phenoloxidase activity in hemolymph was unchanged, but the pool of prophenoloxidase was significantly reduced in virus-infected larvae and further reduced in AcMLF9.ScathL-infected larvae. The median lethal dose (LD(50)) for purified ScathL injected into fifth-instar H. virescens was 11.0 microg/larva. ScathL was also lethal to adult pea aphids, Acyrthosiphon pisum with a similar loss of integrity of the gut and fat body. Injection with purified ScathL.C146A or bovine trypsin at 20 microg/larva did not produce any effect in either insect. These results illustrate the potent insecticidal effects of ScathL cysteine protease activity and the potential for use of ScathL in development of insect resistant transgenic plants when combined with an appropriate delivery system.

Characterisation of functional and insecticidal properties of a recombinant cathepsin L-like proteinase from flesh fly (Sarcophaga peregrina), which plays a role in differentiation of imaginal discs.

ScathL is a cathepsin L-like cysteine proteinase from Sarcophaga peregrina (flesh fly), which is involved in differentiation of imaginal discs, through proteolysis of components of basement membranes. An expression system based on the methylotrophic yeast Pichia pastoris was used to produce recombinant ScathL. Although the expression construct contained the full proprotein coding sequence for ScathL, the proprotein was only detected in culture supernatant at early stages of expression by Western blotting. The purified recombinant protein contained only a polypeptide similar to mature ScathL, as a result of autocatalytic processing. After activation by reducing agents, the enzyme hydrolysed the cathepsin L substrate Z-Phe-Arg-AMC, with optimal activity at pH 5.5. ScathL showed decreasing activity with increasing ionic strength above 0.3M NaCl, and lost activity irreversibly at pH > or = 7.5. The enzyme showed limited activity towards protein substrates, digesting only to large fragments. ScathL was insecticidal towards larvae of the tomato moth, Lacanobia oleracera, following injection into the haemolymph. It caused melanisation, although no evidence of extensive proteolysis in haemolymph or gut was observed. Production of a inactive mutant form of ScathL showed that enzyme activity was necessary for the complete proprotein processing observed during production as a recombinant protein, and for insecticidal activity.

Structural comparison of two CSPG-binding DBL domains from the VAR2CSA protein important in malaria during pregnancy.

Severe malaria during pregnancy is associated with accumulation of parasite-infected erythrocytes in the placenta due to interactions between VAR2CSA protein, expressed on the surface of infected-erythrocytes, and placental chondroitin sulfate proteoglycans (CSPG). VAR2CSA contains multiple CSPG-binding domains, including DBL3X and DBL6 epsilon. Previous structural studies of DBL3X suggested CSPG to bind to a positively charged patch and sulfate-binding site on the concave surface of the domain. Here we present the structure of the DBL6 epsilon domain from VAR2CSA. This domain displays the same overall architecture and secondary structure as that of DBL3X but differs in loop structures, disulfide bond positions and surface charge distribution. In particular, despite binding to CSPG, DBL6 epsilon lacks the key features of the CSPG-binding site of DBL3X. Instead DBL6 epsilon binds to CSPG through a positively charged surface on the distal side of subdomain 2 that is exposed in intact VAR2CSA on the erythrocyte surface. Finally, unlike intact VAR2CSA, both DBL3X and DBL6 epsilon bind to various carbohydrates, with greatest affinity for ligands with high sulfation and negative charge. These studies provide further insight into the structure of DBL domains and suggest a model for the role of individual domains in CSPG binding by VAR2CSA in placental malaria.

Enhancement of antibody responses to influenza vaccination in the elderly following a cognitive-behavioural stress management intervention.

BACKGROUND: Previous research has demonstrated that the psychological morbidity experienced by informal caregivers is associated with increased vulnerability to infectious diseases, in particular influenza. A pragmatic trial was conducted to examine whether a stress management intervention (SMI) could reduce psychological morbidity and enhance the antibody response to influenza vaccination in the elderly, and whether changes in immune response of SMI participants were associated with hypothalamic-pituitary-adrenal (HPA) axis activity. METHODS: Forty-three elderly spousal carers of dementia patients and 27 non-carer controls were recruited. Sixteen carers were allocated to an 8-week SMI or a non-intervention condition (n = 27). The non-carers formed a no treatment, 'normal' comparison group. At the end of the SMI or its equivalent time period, all participants received an influenza vaccination. IgG antibody titres to the vaccine were measured 0, 2, 4 and 6 weeks post-vaccine. RESULTS: There was evidence of elevated distress in both carer groups compared with non-carer controls throughout the SMI period, but no between-group differences in salivary cortisol. Immune responses to the vaccine revealed that 50% of SMI carers, 7% of non-intervention carers and 29% of non-carer controls produced a four-fold increase in antibody titre. CONCLUSIONS: The immune response to influenza vaccination appears amenable to improvement through stress management, although the mechanisms underlying this effect remain unclear.