[A randomized controlled trial on the effect of early eschar dermabrasion combined with antimicrobial soft silicone foam dressing in the treatment of deep partial-thickness burn wounds in children]

Objective: To explore the effect of early eschar dermabrasion combined with antimicrobial soft silicone foam dressing (hereinafter referred to as foam dressing) in treating the deep partial-thickness burn wounds in children. Methods: This study was a randomized controlled trial. From June 2021 to December 2022, 78 pediatric patients with deep partial-thickness burns who met the inclusion criteria were admitted to the Department of Burns in Guiyang Steel Plant Employees Hospital. According to the random number table, the pediatric patients were divided into two groups, with 38 cases left in combined treatment group (with 20 males and 18 females, aged 26.00 (16.75, 39.75) months) and 39 cases in foam dressing group (with 21 males and 18 females, aged 19.00 (14.00, 31.00) months) after the exclusion of one dropped-out child in follow-up. The pediatric patients in combined treatment group underwent eschar dermabrasion of the wound within 48 hours after injury, the wound was covered with foam dressing after operation, and the dressing was replaced once every 7 days; for the pediatric patients in foam dressing group, the wound was sterilized within 48 hours after injury and covered with foam dressing, and the dressing was replaced once every 2 to 3 days. After the wound healing, the children in both groups were routinely applied with silicone gel twice a day for 3 weeks before started wearing elastic sleeves for more than 18 hours a day, and continuously for over than 6 months. The degree of pain during dressing change was evaluated using the children's pain behavior inventory FLACC. The adverse reactions during the treatment period, number of dressing changes, and wound healing time were observed and recorded. Six months after wound healing, the Vancouver scar scale (VSS) was used to evaluate the condition of the wound scar. Results: When changing dressing, the FLACC score for pain of pediatric patients in combined treatment group was 3.5 (2.0, 5.0), which was significantly lower than 6.0 (5.0, 8.0) in foam dressing group (Z=-5.40, P<0.05). During the treatment period, no adverse reactions such as wound edema, fluid accumulation, or peripheral skin rash allergies occurred in any pediatric patient in both groups. The number of dressing changes of pediatric patients in combined treatment group was 3 (3, 4) times, which was significantly less than 8 (7, 10) times in foam dressing group (Z=-7.58, P<0.05). The wound healing time of pediatric patients in combined treatment group was (19±5) days, which was significantly shorter than (25±6) days in foam dressing group (t=-4.48, P<0.05). Six months after wound healing, the VSS score for scar of pediatric patients in combined treatment group was 5 (2, 8), which was significantly lower than 7 (5, 10) in foam dressing group (Z=-3.05, P<0.05). Conclusions: Compared with using foam dressings alone, early eschar dermabrasion combined with foam dressings can reduce the number of dressing changes, alleviate the pain during dressing changes, and shorten the wound healing time in treating children with deep partial-thickness burns, and effectively alleviate scar hyperplasia by combining with anti-scar treatment post burns.

Determination of the potential of induced pluripotent stem cells to differentiate into mouse nucleus pulposus cells in vitro

We determined the potential for induced pluripotent stem (iPS) cells to differentiate into nucleus pulposus (NP)-like cells in mice. iPS cells were generated from tail-tip fibroblasts. We used a pellet culture model with the aim of determining the applicability of iPS cell-based therapy to intervertebral disc degeneration (IVD). The cell pellet was cultured in an NP cell basal medium comprising Dulbecco's modified Eagle's medium supplemented with transforming growth factor beta 1, dexamethasone, ascorbate-2-phosphate, and 1% ITS-Premix. The pellet was evaluated by quantitative reverse transcription polymerase chain reaction, immunohistochemical staining, and biochemical composition. The differentiation of iPS cells into NP cells was demonstrated by the protein and mRNA expression levels of proteoglycan, collagen II, aggrecan, and CD24. Furthermore, increased hydroxyproline content and dimethylmethylene blue staining demonstrated that the collagen II and glycosaminoglycan content in the NP cells increased with time. We have shown that cultured mouse iPS cells can be induced to differentiate into NP cells. Such proof-of-concept opens up the possibility of producing patient-specific NP cells in a relatively simple and straightforward manner with high efficiency. We are confident that such cells could be immediately useful for the study of IVD disease.

Concurrent optical parametric down-conversion in χ(2) nonlinear photonic crystals

We experimentally investigated concurrent parametric downconversion processes in a two-dimensional hexagonally poled lithium tantalate crystal. The substantial enhancement of parametric gain was observed when concurrent processes shared a common parametric beam. Both degenerate and nondegenerate concurrent parametric downconversion processes were studied. Analyses of the spatial forms and output angles showed a strong dependence on the working temperature, during which a well-defined beamlike parametric output was observed. Our results will stimulate the design for coherent high-gain generation of multiple parametric beams and also shed light on the compact engineering of path-entanglement with specific spatial forms based on concurrent spontaneous parametric downconversion processes.

Compact engineering of path-entangled sources from a monolithic quadratic nonlinear photonic crystal

An integrated realization of photonic entangled states becomes an inevitable tendency toward integrated quantum optics. Here we report the compact engineering of steerable photonic path-entangled states from a monolithic quadratic nonlinear photonic crystal. The crystal acts as a coherent beam splitter to distribute photons into designed spatial modes, producing the heralded single-photon and appealing beamlike two-photon path entanglement. We characterize the path entanglement by implementing quantum spatial beating experiments. Such a multifunctional entangled source can be further extended to the high-dimensional fashion and multiphoton level, which paves a desirable way to engineering miniaturized quantum light sources.

Intracellular chloride channel protein CLIC1 regulates macrophage function through modulation of phagosomal acidification

Intracellular chloride channel protein 1 (CLIC1) is a 241 amino acid protein of the glutathione S transferase fold family with redox- and pH-dependent membrane association and chloride ion channel activity. Whilst CLIC proteins are evolutionarily conserved in Metazoa, indicating an important role, little is known about their biology. CLIC1 was first cloned on the basis of increased expression in activated macrophages. We therefore examined its subcellular localisation in murine peritoneal macrophages by immunofluorescence confocal microscopy. In resting cells, CLIC1 is observed in punctate cytoplasmic structures that do not colocalise with markers for endosomes or secretory vesicles. However, when these macrophages phagocytose serum-opsonised zymosan, CLIC1 translocates onto the phagosomal membrane. Macrophages from CLIC1(-/-) mice display a defect in phagosome acidification as determined by imaging live cells phagocytosing zymosan tagged with the pH-sensitive fluorophore Oregon Green. This altered phagosomal acidification was not accompanied by a detectable impairment in phagosomal-lysosomal fusion. However, consistent with a defect in acidification, CLIC1(-/-) macrophages also displayed impaired phagosomal proteolytic capacity and reduced reactive oxygen species production. Further, CLIC1(-/-) mice were protected from development of serum transfer induced K/BxN arthritis. These data all point to an important role for CLIC1 in regulating macrophage function through its ion channel activity and suggest it is a suitable target for the development of anti-inflammatory drugs.

Urinary 2/16 alpha-hydroxyestrone ratio: correlation with serum insulin-like growth factor binding protein-3 and a potential biomarker of breast cancer risk

Metabolism of estradiol occurs via two mutually exclusive hydroxylative pathways, yielding metabolites of divergent biological properties. 2-hydroxyestrone (2OHE1) is anti-estrogenic while 16 alpha-hydroxyestrone (16 alpha OHE1) is a potent estrogen. The ratio of 2OHE1 to 16 alpha OHE1 (2/16 alpha-OHE1 ratio) represents the net in vivo estrogenic activity. In this study, we sought to determine if the urinary 2/16 alpha-OHE1 ratio could be a predictor of breast cancer risk and the factors which influence this ratio. Variables analysed included age at diagnosis, menopausal status, parity, use of oral contraceptives, body mass index, serum levels of insulin-like growth factor-I (IGF-I), IGF binding proteins (BPs) and the presence of breast cancer. Serum and urine were collected from 65 breast cancer patients and 36 controls after an overnight fast. Urinary estrogen metabolites were measured by enzyme immunoassays while serum levels of IGF-I, BP-1 and BP-3 were determined by immunoradiometric assays. 2OHE1 levels and 2/16 alpha-OHE1 ratios were significantly lower (P < 0.05) while 16 alpha OHE1 levels were higher (P < 0.01) in cancer patients. Multiple linear regression analysis showed that levels of urinary metabolites were influenced by parity and breast carcinoma. 2/16 alpha-OHE1 ratio correlated positively with serum BP-3 level (P = 0.03). By multiple logistic regression, 2/16 alpha-OHE1 ratio was the most significant factor predictive of breast cancer. The odds ratio for women with higher 2/16 alpha-OHE1 ratios was 0.10 (0.03-0.38, 95% confidence interval). In conclusion, the profile of urinary estradiol metabolites was distinctly altered in breast cancer patients. In addition, BP-3 may be a potential mechanism by which estradiol metabolites influence breast cancer progression. As 16 alpha OHE1 has been shown to initiate neoplastic transformation of mammary epithelial cells, the 2/16 alpha-OHE1 ratio may serve as a biomarker of increased risk of breast cancer.

Serum DDT and DDE levels in Singapore general population

A simple and fast method was used to determine 1,1'-(2,2,2-trichloroethylene)-bis(4-chlorobenzene) (DDT) and 1,1'-(2,2-dichloroethylidene)-bis(4-chlorobenzene) (DDE) in blood serum. Serum samples pre-treated with formic acid were extracted with n-hexane and determined by gas chromatography (GC-ECD), using PTE-5 capillary column. Detection limits for DDT and DDE were 0.5 ppb. Recovery with a fortified pooled sample at 1 ppb level was 107.0% for DDT and 106.0% for DDE. At 10 ppb level, the recoveries for DDT and DDE were 96.1% and 92.7%, respectively. Eighty-nine random blood samples collected from volunteers were analyzed. The geometric mean (GM) serum level of DDT was 1.9 ppb (0.2-8.9 ppb) and that of DDE was 10.8 ppb (1.5-88.1 ppb). There was a positive correlation between DDE and DDT level (r = 0.33, P < 0.01). The serum DDE level was positively correlated with age (r = 0.49, P < 0.01) and DDT x Age (r = 0.62, P < 0.01). No correlation was observed between DDT and age. These results suggest that DDE, a metabolite of DDT, is cumulative in the body. Therefore blood DDE could be used as a cumulative exposure marker for DDT, whereas blood DDT may be used to reflect its recent exposure.

Evaluation of biomarkers for occupational exposure to benzene

OBJECTIVE

To evaluate the relations between environmental benzene concentrations and various biomarkers of exposure to benzene.

METHODS

Analyses were carried out on environmental air, unmetabolised benzene in urine, trans, trans-muconic acid (ttMA), and three major phenolic metabolites of benzene; catechol, hydroquinone, and phenol, in two field studies on 64 workers exposed to benzene concentrations from 0.12 to 68 ppm, the time weighted average (TWA). Forty nonexposed subjects were also investigated.

RESULTS

Among the five urinary biomarkers studied, ttMA correlated best with environmental benzene concentration (correlation coefficient, r = 0.87). When urinary phenolic metabolites were compared with environmental benzene, hydroquinone correlated best with benzene in air. No correlation was found between unmetabolised benzene in urine and environmental benzene concentrations. The correlation coefficients for environmental benzene and end of shift catechol, hydroquinone, and phenol were 0.30, 0.70, and 0.66, respectively. Detailed analysis, however, suggests that urinary phenol was not a specific biomarker for exposure below 5 ppm. In contrast, ttMA and hydroquinone seemed to be specific and sensitive even at concentrations of below 1 ppm. Although unmetabolised benzene in urine showed good correlation with atmospheric benzene (r = 0.50, P < 0.05), data were insufficient to suggest that it is a useful biomarker for exposure to low concentrations of benzene. The results from the present study also showed that both ttMA and hydroquinone were able to differentiate the background level found in subjects not occupationally exposed and those exposed to less than 1 ppm of benzene. This suggests that these two biomarkers are useful indices for monitoring low concentrations of benzene. Furthermore, these two metabolites are known to be involved in bone marrow leukaemogenesis, their applications in biological monitoring could thus be important in risk assessment.

CONCLUSION

The good correlations between ttMA, hydroquinone, and atmospheric benzene, even at concentrations of less than 1 ppm, suggest that they are sensitive and specific biomarkers for benzene exposure.