Part 2. Comparison of emergency washing solutions in 70% hydrofluoric acid-burned human skin in an established ex vivo explants model

Background: Hydrofluoric acid (HF) is a small and partially dissociated acid (pK_a 3.2), able to deeply penetrate into human skin in addition to the corrosiveness of the hydrogen ion (H⁺) and the toxicity of the fluoride ion (F^?). However, there has been a lack of experimental studies to objectively characterize the results of human HF skin exposure decontamination.

Methodology/principal findings: A previously established experimental method using a human skin explants ex vivo model (Part 1. Experimental 70% hydrofluoric acid (HF) burns: Histological observations in an established human skin explants ex vivo model) described the lesions that appeared following 70% HF penetration. Within 5?min, 70% HF penetrates to the dermis. Using the same experimental conditions, a comparison study of two different washing protocols was performed: water + topical calcium gluconate (CaG) versus Hexafluorine^®. In these conditions, washing for 15?min with running tap water followed by topical CaG ointment only delayed burn onset, while severe tissue damage appeared later. In contrast, after washing with Hexafluorine^® over 10?min, no histological lesions developed. These results are in accordance with the results of accidental human industrial case reports.

Conclusion/significance: Amphoteric and hypertonic Hexafluorine^® can deactivate H⁺ and chelate F^? ions. Based on these results, it should be considered as a promising first-aid decontamination solution to prevent or minimize significant local and systemic consequences of concentrated HF skin exposures.     

Clinical Evaluation of the Trophic Effect of Polydeoxyribonucleotide (PDRN) in Patients Undergoing Skin Explants. A Pilot Study

SUMMARY

Objective: The purpose of this double-blind, randomised, placebo-controlled study was to assess the effects of intramuscular and subcutaneous PDRN in favouring the wound-healing process in donor sites of grafts.

Methods: 26 adult patients of both sexes (15 males and 11 females; mean age: 68.2?±?16.1 years) subjected to skin explants due to plastic surgery were eligible to participate in this double-blind, placebo-controlled study. Patients were randomly allocated into the PDRN group (14 subjects) or the placebo group (12 subjects). PDRN (5625?mg/vial) or placebo were administered by the intramuscular route once daily, associated with a subcutaneous administration of the same dosage form (2 vials every 3 days) for 10 consecutive days.

The primary end point for efficacy was the evolution of wound healing in donor sites, which was evaluated measuring wound surface area and then calculating percentage re-epithelialisation. Secondary end points were local subjective symptoms, such as pain and itching, and objective signs such as perilesional erythema and blisters. Signs and symptoms were quantified through an analogue scale.

Results: At day 7 of the treatment period, the difference in percentage of re-epithelialisation was statistically significant (p?<?0.008) in; favour of the PDRN group. At the end of the observational period, between-group comparison demonstrated that patients treated: with PDRN had a more prompt trophic effect.

No adverse events were reported during the trial.

Conclusions: The findings of our study demonstrated that PDRN is able to modify positively the repair processes in donor sites of autologous skin grafts. This could improve the clinical outcome and decrease the need for additional therapies or hospital stay.     

CPS49‐induced neurotoxicity does not cause limb patterning anomalies in developing chicken embryos

Thalidomide notoriously caused severe birth defects, particularly to the limbs, in those exposed in utero following maternal use of the drug to treat morning sickness. How the drug caused these birth defects remains unclear. Many theories have been proposed including actions on the forming blood vessels. However, thalidomide survivors also have altered nerve patterns and the drug is known for its neurotoxic actions in adults following prolonged use. We have previously shown that CPS49, an anti‐angiogenic analog of thalidomide, causes a range of limb malformations in a time‐sensitive manner in chicken embryos. Here we investigated whether CPS49 also is neurotoxic and whether effects on nerve development impact upon limb development. We found that CPS49 is neurotoxic, just like thalidomide, and can cause some neuronal loss late developing chicken limbs, but only when the limb is already innervated. However, CPS49 exposure does not cause defects in limb size when added to late developing chicken limbs. In contrast, in early limb buds which are not innervated, CPS49 exposure affects limb area significantly. To investigate in more detail the role of neurotoxicity and its impact on chicken limb development we inhibited nerve innervation at a range of developmental timepoints through using β‐bungarotoxin. We found that neuronal inhibition or ablation before, during or after limb outgrowth and innervation does not result in obvious limb cartilage patterning or number changes. We conclude that while CPS49 is neurotoxic, given the late innervation of the developing limb, and that neuronal inhibition/ablation throughout limb development does not cause similar limb patterning anomalies to those seen in thalidomide survivors, nerve defects are not the primary underlying cause of the severe limb patterning defects induced by CPS49/thalidomide.     

Association of mannose‐binding lectin‐2 gene polymorphism with the development of hepatitis C‐induced hepatocellular carcinoma

Background: Development of end‐stage liver and graft disease is suspected to be partially determined by the individual genetic background. Mannose‐binding lectin (MBL) is an important immunomodulatory factor, which is supposed to be involved in complement activation and oncogenesis. Genetic polymorphisms of MBL‐2 alter MBL functionality. The aim of our study was to determine the prevalence of MBL‐2 polymorphism (rs7096206) in hepatitis C virus (HCV)‐induced hepatocellular carcinoma (HCC) based on histological analysis of explanted livers in patients undergoing liver transplantation (LT). Methods: One hundred and seventy‐seven patients, who underwent LT for HCV‐induced liver disease, were genotyped for MBL‐2 by TaqMan genotyping assay. Sixty‐two patients with histologically confirmed HCC were compared with 115 patients without HCC. MBL‐2 genotypes were corelated with the growth patern, tumour size and pretransplant α‐fetoprotein (AFP) level of HCC patients. Results: The prevalence of GG/GC genotypes was significantly higher among HCC patients compared with tumour‐free explanted livers (P=0.004; odds ratio 2.5; 1.3–4.8). GG/GC genotype group was significantly associated with the size of HCC (P=0.022), higher pretransplant AFP level (P=0.010) and bilobar tumour growth (P=0.038). Furthermore, CC genotype was found to be significantly more frequent in AFP‐negative HCCs (P=0.002). Conclusion: Mannose‐binding lectin‐2 polymorphism seems to be involved in the development of pretransplant HCV‐induced HCC and should be further investigated as potential risk factor for HCV‐associated carcinogenesis.     

The effect of sulfasalazine on rheumatoid arthritic synovial tissue chemokine production

Rheumatoid arthritis (RA) is an aggressive inflammatory disease in which chemokines are thought to recruit leukocytes and induce angiogenesis. The aim of this study was to investigate the effects of sulfasalazine (SASP) and its metabolites, sulfapyridine (SP), and 5-aminosalicylic acid (5ASA) on chemokine production by RA synovial tissue explants and interleukin (IL)-1beta-stimulated RA synovial tissue fibroblasts using enzyme-linked immunosorbent assays and flow cytometry. Synovial tissue explants from RA patients secreted a decreased amount of the chemokines IL-8 and growth-related gene product alpha (GROalpha) when treated with SASP over a broad range of concentrations based on the typical clinical dosage of 2 g/day. SP had a significant effect in that it decreased RA synovial tissue explant secretion of IL-8 (22%), GROalpha (55%), and monocyte chemotactic protein-1 (MCP-1) (42%) (P < 0.05). 5ASA had no effect on RA synovial tissue explant production of IL-8 and MCP-1, while increasing GROalpha production. In IL-1beta-stimulated RA synovial tissue fibroblasts, SASP significantly increased chemokine secretion, while SP significantly decreased IL-8 (24%) and GROalpha (21%) secretion (P < 0.05). Flow cytometry showed that the number of IL-8 expressing RA synovial tissue fibroblasts did not significantly change following SP treatment. These data suggest that SASP may function to reduce inflammation in RA through the effects of its metabolite SP to reduce the secretion of the inflammatory chemokines IL-8, GROalpha, and MCP-1.     

Role of Cardiac Glycosides in Regulation of the Growth of Retinal Tissue Explants

We studied the role of cardiac glycosides in the regulation of the growth of retinal tissue explants from 10–12-day-old chicken embryos in organotypic culture. The studied compounds produced a dose-dependent effect on cell proliferation in retinal tissue explants. Ouabain (10⁻¹³ M), strophanthin K (10⁻¹³ M) and digoxin (10⁻¹¹ M) significantly stimulated explant growth. It was hypothesized that the physiological role of endogenous oubain is associated with regulation of tissue modeling. Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 146, No. 12, pp. 651-653, December, 2008     

Rat ventral mesencephalon grown as organotypic slice cultures and co-cultured with striatum,hippocampus, and cerebellum

Summary Tissue slices of rat ventral mesencephalon (VM), striatum, hippocampus and cerebellum were prepared from late fetal (E21) to 7 day old (P7) rats and cultured for 3 to 60 days by the roller tube technique before they were stained immunocytochemically for tyrosine hydroxylase (TH), a marker of dopaminergic (DA) neurons and fibres. The TH immunoreactive (TH-i), DA neurons retained their morphological in vivo characteristics in the VM slice cultures consisting of the substantia nigra (SN) and the ventral tegmental area (VTA). The general morphology of the described neuronal cell types did not appear to change when the VM slices were cocultured with striatal tissue, a major normal target of the DA neurons, but an extensive innervation of the striatum by TH-i nerve fibres was observed. In co-cultures of VM and hippocampus, a minor target organ of DA fibres, growth of TH-i nerve fibres was observed mainly into the opposing edge of the hippocampal slice. In co-cultures of VM and cerebellum, which is normally devoid of DA fibres, no significant growth of TH-i nerve fibres into the cerebellar slices was observed. Besides suggesting a target orientated growth of ventral mesencephalic DA fibres, the results point to the further use of VM slice cultures in the study of the developmental, plastic and regenerative properties of DA neurons.     

Influence of azelastine and some selected drugs on mucociliary clearance

The effect of azelastine and some selected compounds on ciliary beating frequency (CBF) was investigated in vitro using human mucosal samples and in vivo using anesthetized guinea pigs. Further influence of azelastine on mucus secretion was evaluated in mice and on mucociliary clearance in anesthetized rabbits. Azelastine influenced the ciliary beating frequency neither in vitro nor in vivo. Azelastine, similarly to salbutamol, ambroxol, and bromhexine, increased mucus secretion measured by the tracheal output of phenol red. Azelastine dose-dependently enhanced mucociliary clearance measured by elimination of ^99mTc-labeled erythrocytes in rabbits. The activity of azelastine proved to be about 10 times stronger than that of bromhexine. Since the ciliary activity remained unchanged under the influence of azelastine, it is likely that azelastine increases the mucociliary clearance by enhancing bronchial secretion. It is possible that the observed increase in mucociliary clearance may contribute to the beneficial effect of azelastine in the treatment of respiratory diseases. Offprint requests to: I. Szelenyi     

Incorporation of purified plasma fibronectin into explants of articular cartilage from disease-free and osteoarthritic canine joints

The purpose of this study was to determine if articular cartilage was able to accumulate fibronectin, a large molecule of 440,000 daltons, from the external medium, and if so, to compare the extent of accumulation by normal and osteoarthritic cartilage and to localize the sites of fibronectin accumulation within the articular cartilage. The uptake of canine serum albumin, another protein present in plasma and synovial fluid with a lower molecular weight (67,000 daltons) and a lower pI, was compared. Purified plasma fibronectin and canine albumin were labelled with 125I or N-hydroxysuccinimidobiotin by standard procedures and incubated with articular cartilage explants. The 125I-fibronectin that had bound to cartilage components was extracted with 4 M urea, and both extract and cartilage residues were counted. Cartilage accumulated fibronectin to a greater extent than albumin. For normal cartilage, a level of saturation appeared to be reached at an external concentration for fibronectin of about 150 micrograms/ml. Degenerated cartilage accumulated about 10-fold more fibronectin than normal cartilage. Biotinylated fibronectin was localized within frozen sections of articular cartilage by probing with peroxidase-linked avidin. Fibronectin accumulation in normal cartilage was restricted to the articular surface and the cut edge. In degenerated cartilage, penetration of fibronectin was more extensive but proceeded only from the articular surface. Staining of adjacent sections with peroxidase-linked antifibronectin antibody confirmed previous observations that endogenous fibronectin is present throughout the cartilage matrix. The possibility that synovial fluid fibronectin could be a source of cartilage fibronectin, especially in degenerated cartilage, was discussed.