Regional skin blood flow in deep burn wounds: a preliminary report

The Effect of Betulin Diphosphate in Wound Dressings of Bacterial Cellulose-ZnO NPs on Platelet Aggregation and the Activity of Oxidoreductases Regulated by NAD(P)+/NAD(P)H-Balance in Burns on Rats

The inhibition of platelet aggregation, and the activity of oxidoreductases and microhemocirculation in a burn wound on the treatment of burns with wound dressings based on bacterial nanocellulose (BC)-zinc oxide nanoparticles (ZnO NPs)-betulin diphosphate (BDP) were studied. The control of the treatment by BC-ZnO NPs-BDP on burned rats by the noninvasive DLF method showed an increase in perfusion and the respiratory component in wavelet spectra, characterizing an improvement in oxygen saturation in the wound. The study on the volunteers' blood found the inhibition of ADP-induced platelet aggregation by 30-90%. Disaggregation depends on the dose under the action of the ionized form of BDP and ZnO NPs-BDP in a phosphate buffer; it was reversible and had two waves. It was shown on rats that the specific activity of LDHreverse and LDHdirect (control-intact animals) on day 21 of treatment increased by 11-38% and 23%, respectively. The LDHreverse/LDHdirect ratio increased at BC-ZnO NPs-BDP treatment, which characterizes efficient NAD+ regeneration. AlDH activity increased significantly in the first 10 days by 70-170%, reflecting the effectiveness of the enzyme and NAD+ in utilizing toxic aldehydes at this stage of burn disease. The activities of GR and G6PDH using NADP(H) were increased with BC-ZnO NPs-BDP treatment.

Wound Healing Composite Materials of Bacterial Cellulose and Zinc Oxide Nanoparticles with Immobilized Betulin Diphosphate

A design of new nanocomposites of bacterial cellulose (BC) and betulin diphosphate (BDP) pre-impregnated into the surface of zinc oxide nanoparticles (ZnO NPs) for the production of wound dressings is proposed. The sizes of crystalline BC and ZnO NPs (5-25%) corresponded to 5-6 nm and 10-18 nm, respectively (powder X-ray diffractometry (PXRD), Fourier-infrared (FTIR), ultraviolet (UV), atomic absorption (AAS) and photoluminescence (PL) spectroscopies). The biological activity of the wound dressings "BC-ZnO NPs-BDP" was investigated in rats using a burn wound model. Morpho-histological studies have shown that more intensive healing was observed during treatment with hydrophilic nanocomposites than the oleophilic standard (ZnO NPs-BDP oleogel; p < 0.001). Treatment by both hydrophilic and lipophilic agents led to increases in antioxidant enzyme activity (superoxide dismutase (SOD), catalase) in erythrocytes and decreases in the malondialdehyde (MDA) concentration by 7, 10 and 21 days (p < 0.001). The microcirculation index was restored on the 3rd day after burn under treatment with BC-ZnO NPs-BDP wound dressings. The results of effective wound healing with BC-ZnO NPs-BDP nanocomposites can be explained by the synergistic effect of all nanocomposite components, which regulate oxygenation and microcirculation, reducing hypoxia and oxidative stress in a burn wound.

The New Pharmaceutical Compositions of Zinc Oxide Nanoparticles and Triterpenoids for the Burn Treatment

We studied oleogels containing zinc oxide nanoparticles (ZnO NPs) and lupane triterpenoids in sunflower oil for the treatment of burns. The modification of ZnO was carried out by treatment with alcohol solutions of betulin, betulonic acid, betulin diacetate and betulin diphosphate. The properties of modified ZnO NPs were studied by powder XRD (average sizes of 10-20 nm), FTIR (νZnO 450 cm-1), UV-vis (345-360 nm), and blue-violet emission (380-420 nm). The identification and assay of modified ZnO NPs and triterpenoids were estimated. The treatment by oleogels of deep II-degree burns was studied on rats using histological studies, Doppler flowmetry and evaluation of enzymes activity and malonic dialdehyde (MDA) level. After the action of oleogels, burn wound area, and the necrosis decreased twice on the 10th day in comparison with the 1st day after burn. The microcirculation index in the near-wound zone by 20-30% improved compared with the group without treatment. Evaluation of the enzyme activity and the MDA level after treatment by oleogels during the course of 10 days showed them returning to normal. The improvement of antioxidant biochemical indexes, as well as wounds' healing, was mainly determined by the influence of zinc oxide nanoparticles.

Functional properties of granulocytes after thermal injury

Thermal injury, as well as other forms of severe trauma, induces simultaneous hyper- and anti-inflammatory response. While data about decreased number and responsiveness of T lymphocytes are largely consistent, reports concerning granulocytes following trauma are contradictory. Contrary to the evidence on the increased accumulation of granulocytes in the lungs or liver, the results from our laboratory demonstrated reduced granulocyte influx in the wound that heals in conditions of thermal injury. We also demonstrated evidence that indicates impaired signal transduction in granulocytes following thermal injury, as well as their divergent response regarding the adhesiveness, oxidative burst and nitric oxide production at the wound site.

Accidental radioisotope burns - Management of late sequelae

Accidental radioisotope burns are rare. The major components of radiation injury are burns, interstitial pneumonitis, acute bone marrow suppression, acute renal failure and adult respiratory distress syndrome. Radiation burns, though localized in distribution, have systemic effects, and can be extremely difficult to heal, even after multiple surgeries. In a 25 year old male who sustained such trauma by accidental industrial exposure to Iridium192 the early presentation involved recurrent haematemesis, pancytopenia and bone marrow suppression. After three weeks he developed burns in contact areas in the left hand, left side of the chest, abdomen and right inguinal region. All except the inguinal wound healed spontaneously but the former became a non-healing ulcer. Pancytopenia and bone marrow depression followed. He was treated with morphine and NSAIDs, epidural buprinorphine and bupivicaine for pain relief, steroids, antibiotics followed by wound excision and reconstruction with tensor fascia lata(TFL) flap. Patient had breakdown of abdominal scar later and it was excised with 0.5 cm margins up to the underlying muscle and the wound was covered by a latissimis dorsi flap. Further scar break down and recurrent ulcers occurred at different sites including left wrist, left thumb and right heel in the next two years which needed multiple surgical interventions.

Considerations in the treatment of dyslipidemia associated with chronic kidney failure and renal transplantation

In comparison to the general population, individuals with chronic kidney failure experience an increased risk for atherosclerotic cardiovascular disease attributed predominantly to pronounced abnormalities in lipid metabolism. The emerging consensus is that patients with chronic kidney failure should be treated aggressively for dyslipidemia. Statins reduce the risk of cardiovascular disease in a range of at-risk patients; this class of lipid-lowering drugs should be considered first-line treatment of dyslipidemia observed in renal disease patients. Although the statins share a common lipid-lowering effect, there are differences within this class of drugs. The statins differ in their pharmacokinetic effects, drug interaction profiles, and risk of myotoxicity. This article characterizes the dyslipidemia observed in the renal failure setting and reviews the therapeutic considerations involved in selecting among the statins. Lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, and rosuvastatin are the available statins in the United States.

Red blood cell and tissue water content in experimental thermal injury

Oedema formation and changes in local blood flow are known phenomena in burns. The relationship between these two is not clearly described. The aim of this study was firstly to examine both the contents of red blood cells and tissue water in skin and subcutaneous fat after experimental burns of different depths in pigs, and secondly, to confirm our recent findings of the increased dielectric constant of skin and subcutaneous fat reflecting considerable oedema formation, especially in fat after thermal injury.

METHODS

Superficial, partial and full thickness contact burns were created to pigs and followed for 24h. Radioactive Cr-51 labelling of red cells was used to estimate the number of red cells in tissue, and the absolute amount of water was determined by lyophilization.

RESULTS

A decreased number of labelled red cells in skin and an increase in tissue water in subcutaneous fat were found regardless of burn depth. The highest water amount in fat was found in the partial thickness burns.

CONCLUSION

All burn depths resulted in a diminished number of labelled red blood cells in skin and a significant increase in the absolute water amount in subcutaneous fat at 24h post injury. The findings in fat support our recent findings of highly elevated dielectric constants measured by the new in vivo method of dielectric measurements.

Dynamics of tissue neutrophil sequestration after cutaneous burns in rats

BACKGROUND

Neutrophil recruitment in organs after burns may cause local vascular damage, which can be reduced by agents blocking neutrophil adhesion to the vascular wall. Because these agents may increase susceptibility to infection, it is important to characterize the dynamics of neutrophil sequestration in order to optimize an eventual anti-adhesion therapy.

MATERIALS AND METHODS

Rats were scald burned over 20 or 40% of their total body surface area (TBSA) and saline resuscitated. Sham controls were used. Myeloperoxidase (MPO) activity was measured in lungs, liver, kidney, gut, and burned skin up to 1 week postburn. Extravascular accumulation of (125)I-labeled bovine serum albumin ((125)I-BSA) was measured at 12 h postburn.

RESULTS

MPO activity in lungs, liver, and kidney was increased within 3 h postburn and returned to normal within 24-48 h. Peak MPO levels occurred at 6-12 h postburn and were similar for both burn sizes. No MPO increase was observed in gut. MPO levels in burned skin did not increase before 6 h, peaked at 24 h, decreased at 48 h, but remained elevated for up to 7 days. Neutrophil recruitment in lungs and liver was confirmed histochemically. No neutrophils were found in kidneys. Extravascular (125)I-BSA was increased in lungs, liver, kidneys, and gut, in the 40% TBSA group only.

CONCLUSIONS

Neutrophil sequestration in remote organs is a transient phenomenon while neutrophil homing into the wound site is sustained. Neutrophil accumulation dynamics are independent of burn size, although a minimum size is required to trigger vascular damage. Temporary early anti-adhesion therapy to reduce lung and liver neutrophil sequestration with little impact on neutrophil homing into the burn wound may be possible.

Controlled partial skin thickness burns: an animal model for studies of burnwound progression

A practicable, reliable and reproducible model for infliction of partial skin thickness burn lesions in rabbits is presented. The model is dedicated to experimental studies investigating the influence of drugs on burn wounds. A round aluminium stamp with a contact area of 4 cm2, weight 85 g, was heated up to 80 degrees C and applied for 14 s without additional pressure on the depilated dorsal skin of rabbits. This procedure produced the desired partial skin thickness burn injury. The depth of the burn lesions was investigated by HE-stained paraffin sections. The border of the necrotic zone was found in the central third of the dermis in 80% of cases, and in the central two quarters in 100%. These results are achieved when the rabbit's hair at the site of infliction is in the anagen phase of the hair growth cycle. For obtaining reproducible results we recommend using rabbits of the same strain and weight, anagen hair growth phase, the described procedure of infliction, an identical stamp and the specified temperature and infliction time.