Negative-Pressure Wound Therapy Induces Lymphangiogenesis in Murine Diabetic Wound Healing.

BACKGROUND: Decreased lymphangiogenesis contributes to impaired diabetic wound healing. Although negative-pressure wound therapy (NPWT) has been shown to be effective in the treatment of recalcitrant wounds, its impact on lymphangiogenesis remains to be elucidated. In this study, the authors investigate the mechanisms of lymphangiogenesis following NPWT treatment of diabetic murine wound healing. METHODS: Full-thickness dorsal skin wounds (1 × 1 cm 2 ) were excised on 30 db/db mice. The mice were either treated with occlusive covering (control group, n = 15), or received a 7-day treatment of continuous NPWT at -125 mmHg (NPWT group, n = 15). The wounds were photographed on days 0, 7, 10, 14, 21, and 28. Wound tissue was harvested on days 10, 14, 21, and 28 for quantitative analysis. Functional analysis of lymphatic drainage was performed on days 14 and 28 with Evans blue dye tracing. RESULTS: Lymphatic density and diameter, as visualized through podoplanin probing, was significantly higher in the NPWT group compared to the control group ( P < 0.001). NPWT up-regulated the expression of lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1) at the protein level ( P = 0.04), and significant differences were noted in lymphatic density as assessed by LYVE-1 staining ( P = 0.001). Leukocyte infiltration was significantly higher in the NPWT group ( P = 0.01). A higher speed of wound closure ( P < 0.0001) and greater wound bed thickness ( P < 0.0001) were noted in the NPWT group compared to the control group. CONCLUSIONS: NPWT increased the lymphatic vessel density and diameter with LYVE-1 up-regulation. NPWT therefore plays a positive role in lymphangiogenesis in diabetic wound healing. CLINICAL RELEVANCE STATEMENT: The authors' study investigates the association of NPWT and lymphatics and underlines the importance of a more in-depth investigation of the role of lymphatic vessels in wound healing.

Design of a digital PCR optical detection system with multiple fluorescent microdroplets.

The need for accurate nucleic acid testing is increasing with the spread of the global pandemic. Problems such as low efficiency and precision and large volume exist because the number of existing digital polymerase chain reaction (PCR) testing instrument channels is low. In order to solve these problems, a four channel micro drop digital PCR system was designed. The collimating lens set and objective lens of the LED light source are designed in ZEMAX software, and the entire optical path is simulated. It is verified that the light energy utilization rate of the system is over 93% and that stray light interference is marginal.

The Three-Dimensional Structure of Porcine Bladder Scaffolds Alters the Biology of Murine Diabetic Wound Healing.

OBJECTIVE: To determine if the various three-dimensional structures of bioscaffolds affect wound healing by investigating the efficacy of different porcine-derived urinary bladder matrix (UBM) structures in treating murine diabetic wound healing. METHODS: The authors studied three different UBM structures: particulate (pUBM), one-layer freeze-dried sheet (fdUBM), and three-layer laminated sheet (lmUBM). Scanning electron microscopy images of the structures were used to calculate a wound-exposed surface-area-to-volume ratio. A 1.0 × 1.0-cm full-thickness dorsal wound was excised on 90 db/db mice. Mice were either untreated (blank, n = 15), treated with one UBM structure (pUBM, n = 15; fdUBM, n = 15; lmUBM, n = 15), or treated with a combination of either the one- or three-layer sheet over the particulate matrix (fdUBM + pUBM, n = 15; lmUBM + pUBM, n = 15). The authors obtained macroscopic images of the wounds and harvested tissues for analyses at multiple time points. RESULTS: The surface area available to interact with the wound was highest in the pUBM group and lowest in the lmUBM group. Greater wound bed thickness was noted in the fdUBM, fdUBM + pUBM, and lmUBM groups compared with the blank group. Cellular proliferation was significantly higher in the fdUBM and fdUBM + pUBM groups than in the blank group. The lmUBM + pUBM group had the highest collagen deposition. The pUBM group induced significantly higher leukocyte infiltration compared with the lmUBM, lmUBM + pUBM, and blank groups. Microvessel density was highest in the fdUBM + pUBM group. Significant differences in the wound closure rate were noted between the blank group and the fdUBM and fdUBM + pUBM groups. CONCLUSIONS: Assessment of the three UBM bioscaffold structures highlighted differences in the wound-exposed surface area. Variations in wound healing effects, including collagen deposition, cellular proliferation, and angiogenesis, were identified, with combinations of the structures displaying synergistic effects. This study serves as a platform for future scaffold design and offers promising evidence of the benefits of combining various structures of scaffolds.

Adherence to Personal Protective Equipment Guidelines During the COVID-19 Pandemic Among Health Care Personnel in the United States.

OBJECTIVES: Protecting frontline health care workers with personal protective equipment (PPE) is critical during the coronavirus disease (COVID-19) pandemic. Through an online survey, we demonstrated variable adherence to the Centers for Disease Control and Prevention (CDC) PPE guidelines among health care personnel (HCP). METHODS: CDC guidelines for optimal and acceptable PPE usage in common situations faced by frontline health care workers were referenced to create a short online survey. The survey was distributed to national, statewide, and local professional organizations across the United States and to HCP, using a snowball sampling technique. Responses were collected between June 15 and July 17, 2020. RESULTS: Responses totaling 2245 were received from doctors, nurses, midwives, paramedics, and medical technicians in 44 states. Eight states with n > 20 (Arizona, California, Colorado, Louisiana, Oregon, South Carolina, Texas, and Washington) and a total of 436 responses are included in the quantitative analysis. Adherence to CDC guidelines was observed to be highest in the scenario of patient contact when COVID-19 was not suspected (86.47%) and lowest when carrying out aerosol generating procedures (AGPs) (42.47%). CONCLUSIONS: Further research is urgently needed to identify the reasons underlying variability between professions and regions to pinpoint strategies for maximizing adherence and improving the safety of HCPs.

Adherence to Personal Protective Equipment Guidelines During the COVID-19 Pandemic Among Health-Care Personnel: A Louisiana Case Study.

OBJECTIVE: The aim of this study was to determine the extent that appropriate personal protective equipment (PPE), per Centers for Disease Control and Prevention (CDC) guidance, was used during the coronavirus diseases 2019 (COVID-19) pandemic by health-care personnel (HCP) in Louisiana in 5 clinical settings. METHODS: An online questionnaire was distributed to the LA Nursery registry. Appropriate use of PPE in each of the 5 clinical scenarios was defined by the authors based on CDC guidelines. The scenarios ranged from communal hospital space to carrying out aerosol generating procedures (AGPs). A total of 1760 HCP participated between June and July 2020. RESULTS: The average adherence in LA was lowest for the scenario of carrying out AGPs at 39.5% compliance and highest for the scenario of patient contact when COVID-19 not suspected at 82.8% compliance. Adherence among parishes varied widely. Commentary to suggest a shortage of PPE supply and the practice of re-using PPE was strong. CONCLUSIONS: Use of appropriate PPE varied by setting. It was higher in scenarios where only face masks (or respirators) were the standard (ie, community hospital or when COVID-19 not suspected) and lower in scenarios where additional PPE (eg, gloves, eye protection, and isolation gown) was required.

Novel application of autologous micrografts in a collagen-glycosaminoglycan scaffold for diabetic wound healing.

Therapeutic strategies that successfully combine two techniques-autologous micrografting and biodegradable scaffolds-offer great potential for improved wound repair and decreased scarring. In this study we evaluate the efficacy of a novel modification of a collagen-glycosaminoglycan (collagen-GAG) scaffold with autologous micrografts using a murine dorsal wound model. db/db mice underwent a full thickness 1.0 cm2dorsal wound excision and were treated with a collagen-GAG scaffold (CGS group), a modified collagen-GAG scaffold (CGS + MG group) or simple occlusive dressing (Blank group). The modified scaffold was created by harvesting full thickness micrografts and transplanting these into the collagen-GAG membrane. Parameters of wound healing, including cellular proliferation, collagen deposition, keratinocyte migration, and angiogenesis were assessed. The group treated with the micrograft-modified scaffold healed at a faster rate, showed greater cellular proliferation, collagen deposition, and keratinocyte migration with higher density and greater maturity of microvessels. The grafts remained viable within the scaffold with no evidence of rejection. Keratinocytes were shown to migrate from the wound border and from the micrograft edges towards the center of the wound, while cellular proliferation was present both at the wound border and wound bed. We report successful treatment of diabetic wounds with a novel collagen-GAG scaffold modified with full-thickness automicrografts. Differences in cellular migration and proliferation offer maiden evidence on the mechanisms of wound healing. Clinically, the successful scaffold engraftment, micrograft viability and improved wound healing offer promising results for the development of a new therapeutic modality for wound repair.