[Establishment of a topographic map assessment system for facial and cervical wounds and scars of burn patients based on the Delphi method].

Objective: To construct a targeted and accurate evaluation system for facial and cervical wounds and scars of burn patients. Methods: The method combining literature analysis and survey research was adopted, and the basic principles of item system construction were followed. From June to August 2020, based on the aesthetic standards of facial and cervical plastic surgery, the topographic map assessment system for facial and cervical wounds and scars of burn patients was preliminarily formed, focusing on the assessment of wounds and scars in the necks and faces of patients after burns. In September 2020, 38 experts in the relevant fields were consulted in advance and the questionnaire was revised according to the experts' opinions. From December 2020 to March 2021, the Delphi method was applied to conduct inquiry by correspondence with 35 experts in relevant fields from Guangzhou, Shenzhen, Shanghai, Beijing, and other cities, who met the inclusion criteria, and the items were screened and established. The effective recovery rate of inquiry questionnaire was calculated to determine the level of enthusiasm of experts, the average authority coefficient of all items was calculated to determine the level of expert authority, the average importance expert score, the average coefficient of variation, and the average full score rate of all the third-level items were calculated to determine the concentration of expert opinions, the average coefficients of variation and Kendall's harmony coefficients of the importance, sensitivity, and operability expert scores of all the third-level items were calculated to determine the degree of coordination of expert opinions. The Kendall's harmony coefficients for the importance, sensitivity, and operability expert scores of all the third-level items were statistically analyzed with chi-square test. Results: Among the 35 experts consulted by Delphi method, mainly were male, aged (48±10) years, with 8-38 years of working experience, mainly with associate senior titles and above, all with a bachelor's degree or above education background, and of whom 11 were burn experts, 7 were wound repair experts, 4 were plastic surgery experts, and 13 were rehabilitation medicine experts. Finally, a topographic map assessment system for facial and cervical wounds and scars of burn patients was formed, including 4 first-level items, 21 second-level items, 40 third-level items, and 1 mask. The effective recovery rate of inquiry questionnaire was 100% (35/35). The average authority coefficient of all items was 0.89. The average importance expert score was 4.67, the average coefficient of variation of importance expert score was 0.01, and the average full score rate of all the third-level items was 86.3%. The average coefficients of variation of the importance, sensitivity, and operability expert scores of all the third-level items were 0.01, 0.01, and 0.02, respectively. The Kendall's harmony coefficients for the importance, sensitivity, and operability expert scores of all the third-level items were statistically significant (with χ2 values of 1 201.53, 745.67, and 707.07, respectively, P<0.05). Conclusions: The established topographic map assessment system for facial and cervical wounds and scars of burn patients has high scientificity and reliability, which can be used for the evaluation of facial and neck wounds or scars in burn patients.

[Effects and mechanisms of allogeneic epidermal stem cells on the survival of allogeneic full-thickness skin grafts in nude mice with full-thickness skin defect wounds].

Objective: To investigate the effects and mechanisms of allogeneic epidermal stem cells (ESCs) on the survival of allogeneic full-thickness skin grafts in nude mice with full-thickness skin defect wounds. Methods: Experimental research methods were applied. Primary ESCs that appeared paving stone-like after being cultured for 7 d were obtained by enzymatic digestion method from one 4-week-old male BALB/c-NU nude mouse (the same strain, age, and sex below). The cells of third passage were identified by flow cytometry to positively express ESC marker CD44 and negatively express CD45, meanwhile, the positive expression of ESC markers of p63 and integrin 6α, and negative expression of CD71 were identified by immunofluorescence method. The ESCs of third passage in the logarithmic growth phase were used for the following experiments. Twenty-six nude mice were equally divided into phosphate buffered saline (PBS) group and ESCs group according to the random number table. A full-thickness skin defect wound was made on the back of each nude mouse, and then the wounds of the two groups were sprayed with equal volumes of PBS and ESCs, respectively. The wounds were transplanted with full-thickness skin grafts cut from the backs of 4 other nude mice. Each ten nude mice from the two groups were selected, the wound healing and skin survival on post surgery day (PSD) 0 (immediately), 3, 7, 14, and 21 were observed, and the survival ratio and shrinkage rate of skin grafts on PSD 3, 7, 14, and 21 were calculated (the number of sample was the number of surviving skin grafts at each time point); the blood perfusion in the skin grafts on PSD 3, 7, and 14 was detected by the laser speckle blood flow imager, and the blood flow ratio of nude mice skin grafts in ESCs group to PBS group at each time point was calculated (the number of sample was the pair number of surviving skin grafts in group pairing at each time point). The skin graft tissue of each 3 nude mice remained in the two groups were collected on PSD 7, and the mRNA expressions and protein expressions of tumor necrosis factor α (TNF-α), interleukin 8 (IL-8), IL-10, type Ⅰ collagen, type Ⅲ collagen, and matrix metalloproteinase 9 (MMP-9) in the tissue were detected by real-time fluorescent quantitative reverse transcription polymerase chain reaction and Western blotting, respectively. Data were statistically analyzed with Log-rank test, analysis of variance for repeated measurement, one-way analysis of variance, independent sample t test, and Bonferroni correction. Results: Taking the condition on PSD 0 as a reference, the wounds of nude mice in the two groups healed gradually on PSD 3, 7, 14, and 21, and the shrinkage of skin grafts was gradually obvious. Among them, the shrinkage healing of wound of nude mice in PBS group was more significant than that in ESCs group. On PSD 3, the skin graft of 1 nude mouse failed in ESCs group, while the skin graft of 3 nude mice failed in PBS group. On PSD 7, the skin graft of another nude mouse failed in PBS group. The survival ratio of skin grafts of nude mice in the two groups was similar on PSD 3, 7, 14, and 21 (P>0.05). On PSD 3, 7, 14, and 21, the shrinkage rates of skin grafts of nude mice in ESCs group were (9.2±0.4)%, (19.7±1.2)%, (53.6±3.5)%, and (62.2±5.1)%, respectively, which was significantly lower than (11.0±0.9)%, (47.8±2.8)%, (86.1±7.1)%, and (89.7±9.0)% in PBS group (t=5.719, 26.650, 11.940, 7.617, P<0.01). On PSD 3, 7, and 14, blood perfusion signals were observed in the skin grafts of nude mice in the two groups. The average blood perfusion ratios of the skin grafts of nude mice in ESCs group to PBS group were greater than 1, and there was no statistically significant difference in the overall comparison of 3 time points (P>0.05). On PSD 7, compared with those of PBS group, the mRNA and protein expressions of TNF-α, IL-8, type Ⅰ collagen, and type Ⅲ collagen in the skin graft tissue of nude mice in ESCs group were significantly reduced, while the mRNA and protein expressions of IL-10 and MMP-9 in the skin graft tissue of nude mice in ESCs group were significantly increased (in mRNA comparison, t=2.823, 2.934, 2.845, 2.860, 3.877, 2.916, P<0.05). Conclusions: Allogeneic ESCs can reduce the shrinkage of allogeneic full-thickness skin grafts transplanted on full-thickness skin defect wounds in nude mice, promote the formation of new blood vessels between the skin graft and the wound, reduce inflammation and collagen protein expression, and promote the expression of MMP-9, thus improving the survival quality of skin grafts.

Effects of lipids and surfactants on the fermentation production of echinocandin B by Aspergillus nidulans.

AIMS: Echinocandin B (ECB) is a kind of lipopeptide antifungal antibiotic, as well as the key precursor of antifungal drug Anidulafungin. Its efficient bioproduction plays an important role in promoting the industrial production of Anidulafungin. METHODS AND RESULTS: In this study, methyl oleate and Tween 80 were firstly used to enhance the ECB fermentation by Aspergillus nidulans, the results showed that the ECB titre was significantly enhanced with the addition of methyl oleate and Tween 80. Among the lipids, methyl oleate was found to play a pivotal role in increasing the ECB titre to 2123 mg l-1 , which was more than five times higher than that of the control. The addition of Tween 80 in the medium resulted in ECB titre increased to 2584 mg l-1 . The scanning electron microscope (SEM) and N-phenyl-1-naphthylamine (NPN) assay indicated that Tween 80 could influence the cell membrane permeability of A. nidulans, and enhance the intracellular and extracellular substance exchange, therefore lead to the increasing of ECB titre. CONCLUSIONS: Methyl oleate and Tween 80 are optimal carbon sources and surfactants for efficient ECB biosynthesis respectively. SIGNIFICANCE AND IMPACT OF THE STUDY: Surfactant was used in ECB fermentation for the first time, which provided feasible ideas for optimizing the fermentation process of other fungi.

[Current status and quality analysis of interventional therapy for patients with atrial fibrillation in China].

Objective: To define the current status and analyze the medical quality of interventional therapy for patients with atrial fibrillation (AF) in China. Methods: This survey was performed in all seven large regions of China, one to three regional major medical centers were selected from each region. Medical records of patients underwent interventional therapy for AF in the year 2017 were randomly inspected. CHA2DS2-VASc score, prescribed anticoagulant after ablation, indication of left atrial appendage occlusion (LAAO), and complications in the medical records were analyzed. Results: A total of 10 800 AF catheter ablations and 447 LAAOs were performed in 17 regional medical centers in 2017. There were 10/17 centers performing AF catheter ablation<500 cases and 7/17 centers performing LAAO<20 cases. A total of 1 347 cases of catheter ablation and 160 cases of LAAO were selected for further analysis. Among all selected cases, 15.8% (238/1 505) non-valvar AF cases recorded CHA2DS2-VASc scores. The anticoagulation rate after AF catheter ablation was 98.6% (1 328/1 347), anticoagulation rate was higher than 90% in 16 out of 17 centers. The complication and severe complication rates of AF catheter ablation were 0.9% (12/1 347) and 0.4% (5/1 347), respectively. The differences of complication and severe complication rates in AF catheter ablation were similar between centers performing<500 cases and centers performing ≥500 cases (0.5% (2/413) vs. 1.1% (10/934), P>0.05; 0.5% (2/413) vs. 0.3% (3/934), P>0.05). The coincidence rate of LAAO indication was 81.3% (130/160), and the rate was higher in center performing ≥20 cases than in centers performing<20 cases (84.8% (106/125) vs. 68.6% (24/35), P<0.05). The complication and severe complication rates of LAAO were 3.1% (5/160) and 1.9% (3/160). The rate of complications in LAAO was higher in center performing<20 cases than in centers performing ≥20 cases (8.6% (3/35) vs. 1.6% (2/125), P<0.05), and there was no significant difference in severe complication rate (5.7% (2/35) vs. 0.8% (1/125), P>0.05). Conclusions: Interventional therapy for AF in China is generally standardized and safe. The overall incidence of complications post AF interventional ablation is low, the anticoagulation rate after AF catheter ablation is high, and the adherence rate of LAAO indication is fair. The indicators mentioned above vary widely among centers.

[Meta-analysis of the effects of dexmedetomidine combined with ketamine during dressing changes in burn patients].

Objective: To systematically evaluate the safety and efficacy of dexmedetomidine combined with ketamine during dressing changes in burn patients using meta-analysis. Methods: Foreign language databases including PubMed, Cochrane Central, Embase, and Web of Science were searched with the terms of " burns, dexmedetomidine, ketamine, and dressing" , and Chinese databases including Chinese Journal Full-Text Database, Wanfang Data, and China Academic Journal Network Publishing Database were searched with the terms in Chinese version of ",,,,," to retrieve the publicly published randomized controlled trials on the application of dexmedetomidine combined with ketamine for sedation and analgesia during dressing changes in burn patients from the establishment of each database to March 2019. The outcome indexes included systolic blood pressure at 5 minutes after administration, arousal restlessness score, ketamine dosage, dressing change time, body movement/recovery time, pain score, Ramsay sedation scores at 10 minutes after the start of dressing change and 1 hour after dressing change, physician satisfaction score, neuropsychological symptoms, nausea and vomiting times, nausea and vomiting score. RevMan 5.3 and Stata 14.0 statistical software were used to conduct a meta-analysis of eligible studies. Results: A total of 396 burn patients were included in 7 articles, including 198 patients in dexmedetomidine+ ketamine group who received dexmedetomidine and ketamine for sedation and analgesia, and 198 patients in ketamine alone group who received ketamine alone for sedation and analgesia. The bias risks of the seven studies included were uncertain. Compared with those of ketamine alone group, the systolic blood pressure at 5 minutes after administration, arousal restlessness score, nausea and vomiting score of patients in dexmedetomidine+ ketamine group were significantly decreased, with standardized mean differences of -13.89, -0.84, and -0.99 (95% confidence interval=-20.89--6.89, -1.17--0.52, -1.31--0.68, P<0.01), the Ramsay sedation score at 10 minutes after the start of dressing change and that at 1 hour after dressing change were significantly increased, with standardized mean differences of 1.53 and 0.72 (95% confidence interval=1.05-2.02, 0.13-1.31, P<0.05 or P<0.01), and the number of neuropsychological symptom and number of nausea and vomiting were significantly reduced, with relative risks of 0.20 and 0.16 (95% confidence interval=0.07-0.58, 0.05-0.58, P<0.01). The patients in the two groups were similar in ketamine dosage, dressing change time, body movement/recovery time, pain score, and physician satisfaction score. There was no publication bias in dressing change time or ketamine dosage (P>0.05), while the other indexes might have publication bias (P<0.05). Conclusions: Compared with ketamine alone, combination of dexmedetomidine and ketamine during dressing changes in burn patients can reduce the occurrence of restlessness, nausea and vomiting, neuropsychological symptoms, and other complications, better stabilize blood pressure, and enhance sedation effect.

[Clinical characteristics of cardiomyopathies complicated with ventricular thrombosis].

Objective: To summarize the clinical characteristics of cardiomyopathy complicated with ventricular thrombosis. Methods: The clinical data of inpatients suffered from cardiomyopathy complicated with ventricular thrombosis in Fuwai Hospital between January 2015 and May 2019 were analyzed retrospectively. Results: A total of 125 cases were reviewed, and 24.8% were female. Dilated cardiomyopathy was the most common disease (62.4%), followed by arrhythmogenic right ventricular cardiomyopathy (ARVC) (13.6%) and hypertrophic cardiomyopathy (11.2%). There were 74.4% thrombosis in left ventricle, 12.8% in right ventricle and 12.8% in biventricle. The proportions of right ventricle thrombosis were higher in ARVC than in other cardiomyopathies (52.9% vs 6.5%, P<0.01). The majority suffered from cardiac function New York Heart Association (NYHA) Class Ⅲ (45.6%) and class Ⅳ (39.2%). The ratio of NYHA Class Ⅳ was higher in female patients than in male ones (25.8% vs 10.6%, P<0.05). In lab detection, positive results of D-Dimer and N terminal-pro B type natriuretic peptide (NT-proBNP) accounted for 72.8% and 97.6%, respectively. There were 2.5% patients died in the hospital or discharged because of the worsening of illness, the chances were higher in female than male patients (9.7% vs 0, P<0.01). Among these patients, one succumbed to massive ischemic stroke caused by ventricular thrombus detachment under standard anticoagulation therapy. Conclusions: Dilated cardiomyopathy is the most common cardiomyopathy complicated with ventricular thrombosis. The most common location of thrombosis is left ventricle. Right ventricle thrombosis is more common in ARVC. The majority suffer from moderate or severe cardiac dysfunction. Higer proportion of female patients suffer from anemia, severe condition and poor prognosis.

[Advances in the research of heterotopic ossification caused by burns].

Heterotopic ossification is a rare complication of burns, and its incidence and risk factors are still unclear. Through summarizing the literature on heterotopic ossification caused by burns at home and abroad, the author searched for the risk factors of heterotopic ossification after burn and the new progress of its prevention and treatment. It was realized that the size, depth and healing time of burn wounds were related to heterotopic ossification; the nonsteroidal anti-inflammatory drugs, radiation therapy, and their combination therapy can be used for the prevention of heterotopic ossification; surgery is an effective means of treating heterotopic ossification.

Three-dimensional digital reconstruction of skin epidermis and dermis.

This study describes how three-dimensional (3D) human skin tissue is reconstructed, and provides digital anatomical data for the physiological structure of human skin tissue based on large-scale thin serial sections. Human skin samples embedded in paraffin were cut serially into thin sections and then stained with hematoxylin-eosin. Images of serial sections obtained from lighting microscopy were scanned and aligned by the scale-invariant feature transform algorithm. 3D reconstruction of the skin tissue was generated using Mimics software. Fibre content, porosity, average pore diameter and specific surface area of dermis were analysed using the ImageJ analysis system. The root mean square error and mutual information based on the scale-invariant feature transform algorithm registration were significantly greater than those based on the manual registration. Fibre distribution gradually decreased from top to bottom; while porosity showed an opposite trend with irregular average pore diameter distribution. A specific surface area of the dermis showed a 'V' shape trend. Our data suggested that 3D reconstruction of human skin tissue based on large-scale serial sections could be a valuable tool for providing a highly accurate histological structure for analysis of skin tissue. Moreover, this technology could be utilized to produce tissue-engineered skin via a 3D bioprinter in the future.

[Meta-analysis on the clinical effects of allogenic acellular dermal matrix treatment for diabetic foot ulcer].

Objective: To analyze the clinical effects of allogenic acellular dermal matrix (ADM) treatment for diabetic foot ulcer (DFU) with meta-analysis. Methods: Databases including PubMed, Cochrance Library, Embase, and OVID EBM Reviews were searched using key words " diabetic foot, diabetic ulcer, diabetic wound, acellular dermal matrix, acellular dermal regenerative tissue matrix, acellular regenerative tissue matrix, AlloDerm, SureDerm, KaroDerm, Graftjacket, Hyalomatrix PA, and Hyalograft 3D" , and Chinese Biological Abstracts, Chinese Journals Full-text Database, VIP Database, and Wanfang Database were searched using key words in Chinese version ",,," to obtain the published trials of allogenic ADM treatment for DFU from January 1990 to July 2015, and then meta-analysis was used to analyze the trials. The measurement indexes were wound contraction rate, wound healing rate, complete epithelization time of wound, and complication rate. Meta-analysis was conducted by RevMan 5.2 statistical software. Results: A total of 5 trials involving 426 DFU patients were included, with 224 patients in group ADM who received allogenic ADM treatment and 202 patients in conventional treatment group (CT) who received conventional moist treatment. There was no statistically significant difference between group ADM and group CT in wound contraction rate, with mean difference 20.34 (with 95% confidence interval -25.27-65.94, P=0.38). The wound healing rate of patients in group ADM was higher than that in group CT, with relative risk (RR) 1.90 (with 95% confidence interval 1.29-2.80, P<0.01). There was no statistically significant difference between group ADM and group CT in complete epithelization time of wound, with mean difference 1.20 (with 95% confidence interval -2.93-0.52, P=0.17). The complication rate of patients in group ADM was lower than that in group CT, RR=0.54 (with 95% confidence interval 0.38-0.76, P<0.001). Publication bias might exist in wound contraction rate, wound healing rate, complete epithelization time of wound, and complication rate. Conclusions: Compared with conventional moist treatment, allogenic ADM treatment can accelerate wound healing and reduce complication rate in patients with DFU.

IRAK1 mediates TLR4-induced ABCA1 downregulation and lipid accumulation in VSMCs.

The activation of Toll-like receptor 4 (TLR4) signaling has an important role in promoting lipid accumulation and pro-inflammatory effects in vascular smooth muscle cells (VSMCs), which facilitate atherosclerosis development and progression. Previous studies have demonstrated that excess lipid accumulation in VSMCs is due to an inhibition of the expression of ATP-binding cassette transporter A1 (ABCA1), an important molecular mediator of lipid efflux from VSMCs. However, the underlying molecular mechanisms of this process are unclear. The purpose of this study was to disclose the underlying molecular mechanisms of TLR4 signaling in regulating ABCA1 expression. Primary cultured VSMCs were stimulated with 50 µg/ml oxidized low-density lipoprotein (oxLDL). We determined that enhancing TLR4 signaling using oxLDL significantly downregulated ABCA1 expression and induced lipid accumulation in VSMCs. However, TLR4 knockout significantly rescued oxLDL-induced ABCA1 downregulation and lipid accumulation. In addition, IL-1R-associated kinase 1 (IRAK1) was involved in the effects of TLR4 signaling on ABCA1 expression and lipid accumulation. Silencing IRAK1 expression using a specific siRNA reversed TLR4-induced ABCA1 downregulation and lipid accumulation in vitro. These results were further confirmed by our in vivo experiments. We determined that enhancing TLR4 signaling by administering a 12-week-long high-fat diet (HFD) to mice significantly increased IRAK1 expression, which downregulated ABCA1 expression and induced lipid accumulation. In addition, TLR4 knockout in vivo reversed the effects of the HFD on IRAK1 and ABCA1 expression, as well as on lipid accumulation. In conclusion, IRAK1 is involved in TLR4-mediated downregulation of ABCA1 expression and lipid accumulation in VSMCs.

Randomized clinical trial of autologous skin cell suspension combined with skin grafting for chronic wounds.

BACKGROUND: Treatment of chronic wounds using traditional surgical procedures is challenging because of the low graft take rates. This study investigated the combination approach of split-thickness autografts with harvested skin cell suspension for chronic wound treatment. METHODS: This randomized clinical trial enrolled patients with chronic wounds between March 2012 and December 2013. Patients who were assigned randomly to the active treatment received a split-thickness autograft combined with harvested skin cell suspension. Control patients received the split-thickness autograft alone. The primary outcome was the rate of complete wound closure by postoperative day 28. Analysis was by intention to treat. Patients who achieved wound closure were followed up for a minimum of 6 months to evaluate the quality of healing. RESULTS: A total of 88 patients were included, 44 in each group. More patients achieved complete wound closure in the skin cell group than in the control group (41 versus 34 patients; P = 0·035). Complete wound closure was observed at a median of 14 (95 per cent c.i. 12·0 to 16·0) days in the skin cell group and 20 (15·7 to 24·3) days in the control group (P = 0·001). The skin cell group had significantly fewer complications (4 versus 11 patients; P = 0·047). The autografted sites displayed better physical attributes and a reduced tendency for wound recurrence in the skin cell group. CONCLUSION: Complementary split-thickness autologous skin grafting with autologous skin cells harvested using ReCell® (Avita Medical, Cambridge, UK) technology improved the healing rate of chronic wounds. REGISTRATION NUMBER: UMIN000011966 (http://www.umin.ac.jp/ctr).

Expression of insulin-like growth factor-1 receptor in keloid and hypertrophic scar.

BACKGROUND: Keloid and hypertrophic scar (HS) are two pathological forms of excessive dermal fibrosis, which are due to aberrant wound-healing responses. Accumulating evidence suggests that aberrant activity of growth factors and increased numbers of growth factor receptors play an important role in the formation of pathological scar. AIM: We examined the expression level of insulin-like growth factor-1 receptor (IGF-IR) in keloid, HS and normal skin. METHODS: IGF-IR expression was analyzed by immunohistochemistry, real-time PCR and western blotting on tissues and fibroblasts from 30 patients, comprising 10 patients with keloid and 20 with HS (10 with immature and 10 with mature HS), and from 10 age-matched and sex-matched healthy controls. RESULTS: Immunoreactivity to IGF-IR was found in dermal fibroblasts of keloid (90%), immature HS, (80%) and mature HS (30%), but not in normal skin. There was no statistically significant difference in immunoreactivity scores between keloid and immature HS, but there was a significant difference (P < 0.01) between mature and immature HS. Real-time PCR and western blot analysis confirmed that there was high expression of IGF-IR in keloid and immature HS fibroblasts, but not in mature HS or normal skin fibroblasts. IGF-IR was expressed in the overlying epidermis, and there was no significant difference between the groups. CONCLUSIONS: IGF-IR may be involved in the pathogenesis of keloid and HS. Given that IGF-IR are predominantly expressed on dermal fibroblasts, targeting of IGF-IR in fibroblasts may be of benefit to prevent scarring.

Characterization of immobilized enzymes in polyurethane foams in a dynamic bed reactor.

beta-D-Galactosidase (E 3.2.1.23) from Aspergillus oryzae was immobilized with polyurethane foam (PUF). Among several immobilization methods attempted in this work, the immobilized enzyme preparation by in-situ co-polymerization between enzyme and prepolymer HYPOL 3000 showed the highest activity. The intrinsic kinetics of PUF-immobilized enzyme was determined in a dynamic bed reactor, used to increase transport rates. The immobilization mechanism in PUF was studied by measurements of immobilized enzyme kinetics and by using scanning electron microscopy combined with immuno-gold labeling techniques. The results showed that immobilization was predominantly by covalent bonding between primary amino groups of beta-D-galactosidase and isocyanate groups of the prepolymers. Entrapment in the PUF micropores assisted the immobilization of enzymes, and adsorption on the surface of macropores was not important for immobilization. The bicinchoninic acid method was applied for the determination of PUF loading capacity and specific enzyme activity and used to determine enzyme deactivation during immobilization.