Techniques, Outcomes, and Complications of Preloaded, Trifolded Descemet Membrane Endothelial Keratoplasty Using the DMEK EndoGlide

PURPOSE

To describe 2 insertion techniques, outcomes, and complications of preloaded, trifolded Descemet membrane endothelial keratoplasty (DMEK) cases using the DMEK EndoGlide inserter.

METHODS

This retrospective, consecutive case series analyzed the first 35 cases using the DMEK EndoGlide performed between October 2018 and October 2019 at a single center. Preloaded, trifolded DMEK tissues were delivered through a fluid-injected or pull-through technique. To inject the tissue, a burst of fluid was delivered into the lumen of the injector with a second instrument. Postoperatively, best-spectacle corrected visual acuity (BSCVA), pachymetry, graft survival, and complications were assessed.

RESULTS

Thirty-five eyes of 29 patients underwent DMEK alone (n = 11), with cataract surgery (n = 21), or with additional surgeries (n = 3). Of these, 19 (54.3%) grafts were injected. Video analysis revealed a median time of 3.5 minutes from graft insertion to opening for gas insertion. Median preoperative BSCVA of 0.398 logMAR improved to 0.097 logMAR (P = 0.02) at 9 months. Median pachymetry decreased from 619 μm to 551 μm (P = 0.03) at 9 months. Median donor endothelial cell count of 2890.5 cells/mm2 reduced to 2123 cells/mm2 (26.6% endothelial cell loss; P = 0.008) 6 months postoperatively. One (2.9%) graft failed due to inverted marking at the eye bank and subsequent reverse implantation.

CONCLUSIONS

Pre-loaded, tri-folded tissues can be implanted with acceptable levels of endothelial cell loss. We describe a no-touch method of injecting pre-loaded, tri-folded tissue and highlight incorrect marking as a potential complication. This may not be identifiable intraoperatively due to lack of scroll formation.

Osteoporosis in Skin Diseases

Osteoporosis (OP) is defined as a generalized skeletal disease characterized by low bone mass and an alteration of the microarchitecture that lead to an increase in bone fragility and, therefore, an increased risk of fractures. It must be considered today as a true public health problem and the most widespread metabolic bone disease that affects more than 200 million people worldwide. Under physiological conditions, there is a balance between bone formation and bone resorption necessary for skeletal homeostasis. In pathological situations, this balance is altered in favor of osteoclast (OC)-mediated bone resorption. During chronic inflammation, the balance between bone formation and bone resorption may be considerably affected, contributing to a net prevalence of osteoclastogenesis. Skin diseases are the fourth cause of human disease in the world, affecting approximately one third of the world's population with a prevalence in elderly men. Inflammation and the various associated cytokine patterns are the basis of both osteoporosis and most skin pathologies. Moreover, dermatological patients also undergo local or systemic treatments with glucocorticoids and immunosuppressants that could increase the risk of osteoporosis. Therefore, particular attention should be paid to bone health in these patients. The purpose of the present review is to take stock of the knowledge in this still quite unexplored field, despite the frequency of such conditions in clinical practice.

Secondary spontaneous pneumothorax and bullous lung disease in cannabis and tobacco smokers: A case-control study

Background

The notion that smoking cannabis may damage the respiratory tract has been introduced in recent years but there is still a paucity of studies on this subject. The aim of this study was to investigate the relationship between cannabis smoking, pneumothorax and bullous lung disease in a population of operated patients.

Methods and findings

We performed a retrospective study on patients operated on for spontaneous pneumothorax. Patients were divided into three groups according to their smoking habit: cannabis smokers, only-tobacco smokers and nonsmokers. Cannabis lifetime exposure was expressed in dose-years (1d/y = 1 gram of cannabis/week for one year). Clinical, radiological and perioperative variables were collected. The variables were analyzed to find associations with smoking habit. The impact of the amount of cannabis consumption was also investigated by ROC curves analysis.

Of 112 patients, 39 smoked cannabis, 23 smoked only tobacco and 50 were nonsmokers. Median cannabis consumption was 28 dose/years, median tobacco consumption was 6 pack/years. Cannabis smokers presented with more severe chronic respiratory symptoms and bullous lung disease and with a higher incidence of tension pneumothorax than both tobacco smokers and nonsmokers. Cannabis smokers also developed a larger pneumothorax, experienced prolonged postoperative stay and demonstrated a higher incidence of pneumothorax recurrence after the operation than nonsmokers did. The risk of occurrence of chronic respiratory symptoms and bullous lung disease in cannabis smokers was dose-related.

Conclusions

Cannabis smoking seems to increase the risk of suffering from respiratory complaints and can have detrimental effects on lung parenchyma, in a dose-dependent manner. Cannabis smoking also negatively affected the outcome of patients operated for spontaneous pneumothorax. A history of cannabis abuse should always be taken in patients with pneumothorax. There may be need for a specific treatment for pneumothorax in cannabis smokers.

Photo Rounds: Painful blisters on fingertips and toes

Our patient had visited the emergency department for painful blisters on her fingertips and toes. A follow-up visit to our clinic unearthed the cause.

Amino acid duplication in the coiled-coil structure of collagen XVII alters its maturation and trimerization causing mild junctional epidermolysis bullosa

The function and stability of collagens depend on the accurate triple helix formation of three distinct polypeptide chains. Disruption of this triple-helical structure can result in connective-tissue disorders. Triple helix formation is thought to depend on three-stranded coiled-coil oligomerization sites within non-collagenous domains. However, only little is known about the physiological relevance of these coiled-coil structures. Transmembrane collagen XVII, also known as 180 kDa bullous pemphigoid antigen provides mechanical stability through the anchorage of epithelial cells to the basement membrane. Mutations in the collagen XVII gene, COL17A1, cause junctional epidermolysis bullosa (JEB), characterized by chronic trauma-induced skin blistering. Here we exploited a novel naturally occurring COL17A1 mutation, leading to an in-frame lysine duplication within the coiled-coil structure of the juxtamembranous NC16A domain of collagen XVII, which resulted in a mild phenotype of JEB due to reduced membrane-anchored collagen XVII molecules. This mutation causes structural changes in the mutant molecule and interferes with its maturation. The destabilized coiled-coil structure of the mutant collagen XVII unmasks a furin cleavage site that results in excessive and non-physiological ectodomain shedding during its maturation. Furthermore, it decreases its triple-helical stability due to defective coiled-coil oligomerization, which makes it highly susceptible to proteolytic degradation. As a consequence of altered maturation and decreased stability of collagen XVII trimers, reduced collagen XVII is incorporated into the cell membrane, resulting in compromised dermal-epidermal adhesion. Taken together, using this genetic model, we provide the first proof that alteration of the coiled-coil structure destabilizes oligomerization and impairs physiological shedding of collagen XVII in vivo.

A New Method for Revision of Encapsulated Blebs after Trabeculectomy: Combination of Standard Bleb Needling with Transconjunctival Scleral Flap Sutures Prevents Early Postoperative Hypotony

Purpose

A simple needling procedure is the standard method for restoring the function of an encapsulated bleb after trabeculectomy. However, postoperative hypotony represents a possible hazard. This study describes a new surgical approach for treating encapsulated blebs with reduced risk of early postoperative hypotony: bleb needling combined with transconjunctival sutures tightening the scleral flap directly.

Methods

The study included two groups of 23 patients with failing bleb following trabeculectomy: “Group 1” underwent simple needling revision of the filtering bleb and served as a control group, while “Group 2” received needling revision with additional transconjunctival scleral flap sutures, if intraoperatively the intraocular pressure was estimated to be very low. Intraocular pressure (IOP), postoperative management and complications were analyzed over a follow-up period of 4 weeks postoperatively. Results were compared using t-test or Mann-Whitney U-tests.

Results

Adverse effects occurred with a higher frequency after sole needling of the bleb (5 cases of choroidal effusion and 1 case of choroidal hemorrhage) than after the combined method with additional scleral sutures (1 case of choroidal effusion). The IOP on the first postoperative day was significantly lower in group 1, with 9.43 ± 9.01 mm Hg vs. 16.43 ± 8.35 mm Hg in group 2 (P = 0.01). Ten patients with ocular hypotony (IOD of 5 mmHg or lower) were found in group 1 and only two in group 2. One week and one month after surgery the intraocular pressure was similar in both groups (P>0.05).

Conclusions

This new needling technique with additional transconjunctival scleral flap sutures appears to reduce postoperative hypotony, and may thus protect from further complications, such as subchoroidal hemorrhage.

Hand Blisters in Major League Baseball Pitchers: Current Concepts and Management

Friction blisters are a common sequela of many athletic activities. Their significance can range from minor annoyance to major performance disruptions. The latter is particularly true in baseball pitchers, who sustain repeated trauma between the baseball seams and the fingers of the pitching hand, predominately at the tips of the index and long fingers. Since 2010, 6 Major League Baseball (MLB) players accounted for 7 stints on the disabled list (DL) due to blisters. These injuries resulted in a total of 151 days spent on the DL. Since 2012, 8 minor league players spent time on the DL due to blisters. Moreover, there have been several documented and publicized instances of professional baseball pitchers suffering blisters that did not require placement on the DL but did result in injury time and missed starts. The purpose of this article is to review the etiology and pathophysiology of friction blisters with particular reference to baseball pitchers; provide an overview of past and current prevention methods; and discuss our experience in treating friction blisters in MLB pitchers.

Assessment of Filtration Bleb and Endplate Positioning Using Magnetic Resonance Imaging in Eyes Implanted with Long-Tube Glaucoma Drainage Devices

Background

To evaluate ocular fluid filtration and endplate positioning in glaucomatous eyes with long-tube glaucoma drainage devices (GDDs) using magnetic resonance imaging (MRI) and the effects of various factors on postoperative intraocular pressure (IOP).

Methods

This observational case series included 27 consecutive glaucomatous eyes (18 men, 7 women; mean age ± standard error, 63.0±2.0 years) who underwent GDD implantation (n = 8 Ahmed Glaucoma Valves [AGV] and n = 19 Baerveldt Glaucoma Implants [BGI]). Tubes were inserted into the pars plana in 23 eyes and anterior chamber in 4 eyes. Six months postoperatively, high-resolution orbital images were obtained using 3-Tesla MRI with head-array coils, and the filtering bleb volume, bleb height, and distances between the anterior endplate edge and corneal center or limbus or between the endplate and orbital wall were measured.

Results

In MR images obtained by three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequences, the shunt endplate was identified as low-intensity signal, and the filtering bleb was identified as high-intensity signals above and below the endplate in all eyes. The 6-month-postoperative IOP level was correlated negatively with bleb volume (r = -0.4510, P = 0.0182) and bleb height (r = -0.3954, P = 0.0412). The postoperative IOP was significantly (P = 0.0026) lower in BGI-implanted eyes (12.2±0.7 mmHg) than AGV-implanted eyes (16.7±1.2 mmHg); bleb volume was significantly (P = 0.0093) larger in BGI-implanted eyes (478.8±84.2 mm³) than AGV-implanted eyes (161.1±52.3 mm³). Other parameters did not differ.

Conclusions

The presence of intraorbital/periocular accumulation of ocular fluid affects postoperative IOP levels in eyes implanted with long-tube GDDs. Larger filtering blebs after BGI than AGI implantations explain lower postoperative IOP levels achieved with BGI than AGV. The findings will contribute to better understanding of IOP reducing mechanism of long-tube GDDs.

Transplant rejection following endothelial keratoplasty and penetrating keratoplasty in the United Kingdom: incidence and survival

PURPOSE

To investigate the incidence and outcome of cornea transplant rejection following endothelial keratoplasty (EK) and penetrating keratoplasty (PK) for Fuchs endothelial dystrophy (FED) and pseudophakic bullous keratopathy (PBK).

DESIGN

Multicenter cohort study.

METHODS

Patients registered on the United Kingdom Transplant Registry (UKTR) who had an EK or PK for FED or PBK between April 1, 2005 and March 31, 2011 were included. Data were collected from UKTR forms at 1 and 2 years. Postoperative steroid use varies between surgeons and cannot be captured in this reporting system. Rejection events were identified as those recorded as endothelial rejection.

RESULTS

A total of 3486 corneal transplants were undertaken: 1973 for FED, 1513 for PBK. For FED, 2-year rejection-free survival was 93% (95% confidence interval [CI] 90%-94%) for PK and 94% (95% CI 92%-96%) for EK (P = .3). In transplants that had a rejection episode, 50% of PKs (17) and 60% of EKs (15) subsequently failed. For PBK, 2-year rejection-free survival for PK was 88% (95% CI 86%-90%) and 90% (95% CI 86%-92%) for EK (P = .6). In transplants that had a rejection episode, 85% of PKs (41) and 76% of EKs (22) subsequently failed. Inflammation (ie, conjunctival injection, presence of keratic precipitates and intraocular signs) at the time of surgery for patients with FED was significant for developing rejection: 3.5 times greater compared with those with no inflammation (P = .02).

CONCLUSIONS

There is no significant difference in rejection-free survival between EK and PK for FED or PBK. The presence of inflammation is an important risk factor, and attention to its control before and following surgery is important.

Deletion of the major bullous pemphigoid epitope region of collagen XVII induces blistering, autoimmunization, and itching in mice

Bullous pemphigoid (BP) is the most common autoimmune subepidermal blistering skin disease with a characteristic of pruritus and blistering. BP patients carry inflammation-triggering autoantibodies against the collagen XVII (ColXVII, also known as BP180) juxtamembraneous extracellular noncollagenous 16A (NC16A) domain involved in ectodomain shedding. Deletion of the corresponding NC14A region in a genetically modified mouse model (ΔNC14A) decreased the amount of ColXVII in skin, but it did not prevent ectodomain shedding. Newborn ΔNC14A mice had no macroscopic phenotypic changes. However, subepidermal microblisters, rudimentary hemidesmosomes, and loose basement membrane zone were observed by microscopy. ΔNC14A mice grow normally, but at around 3 months of age they start to scratch themselves and develop crusted erosions. Furthermore, perilesional eosinophilic infiltrations in the skin, eosinophilia, and elevated serum IgE levels are detected. Despite the removal of the major BP epitope region, ΔNC14A mice developed IgG and IgA autoantibodies with subepidermal reactivity, indicating autoimmunization against a dermo-epidermal junction component. Moreover, IgG autoantibodies recognized a 180-kDa keratinocyte protein, which was sensitive to collagenase digestion. We show here that ΔNC14A mice provide a highly reproducible BP-related mouse model with spontaneous breakage of self-tolerance and development of autoantibodies.

Quantitative assessment of emphysematous parenchyma using multidetector-row computed tomography in patients scheduled for endobronchial treatment with one-way valves†

OBJECTIVES

To investigate the role of volume quantitative assessment using multidetector-row computed tomography to select patients scheduled for endobronchial one-way valves treatment.

METHODS

Twenty-five consecutive patients (15 with heterogeneous emphysema and 10 with giant emphysematous bulla) undergoing endobronchial valves treatment were enrolled. All patients were studied pre- and postoperatively with standard pulmonary functional tests and quantitative volume assessment of target lobe and entire lung. Emphysematous parenchyma was obtained applying density thresholds of -1.024/-950 Hounsfield units. Among different subtype of patients, we evaluated: (i) the differences between preoperative versus postoperative data; (ii) the correlation between functional and volumetric quantification changes and (iii) the critical threshold value of volumetric quantification of the target lobe in close association with clinical effects.

RESULTS

Among heterogeneous emphysematous and giant emphysematous bulla patients, a significant improvement of flow-expiratory volume in 1 s (from 36.9 ± 15.3 to 43.9 ± 10.4; P = 0.01; and from 35.8 ± 6.0 to 47.5 ± 7.9; P < 0.0001, respectively); and of forced vital capacity (from 41.9 ± 5.9 to 47.3 ± 9.3; P = 0.0009 and from 40.7 ± 5.9 to 48.8 ± 4.9; P = 0.0002, respectively); and a significant reduction of residual volume (from 185 ± 14 to 157 ± 14.7; P = 0.005; and from 196 ± 13.5 to 137 ± 21; P < 0.0001, respectively) and of total lung volume (from 166.7 ± 13 to 137 ± 18 ; P = 0.0003, and from 169 ± 15 to 134 ± 18; P < 0.0001, respectively) were seen after treatment. The volumetric measurements showed a reduction of volume of the treated lobe among heterogeneous emphysematous patients (from 1448 ± 204 to 1076 ± 364; P = 0.0008); and in those with giant emphysematous bulla (from 1668 ± 140 to 864 ± 199; P < 0.0001). The entire lung and target lobe volume changes were inversely correlated with change in forced expiratory volume in 1 s in patients with heterogeneous emphysematous (r = -0.7; P = 0.0006; and r = -0.7; P = 0.0009, respectively) and giant emphysematous bulla (r = -0.8; P = 0.001; and r = -0.7; P = 0.009, respectively). Among patients with heterogenous emphysematous and giant emphysematous bulla, the value of sensitivity and specificity were 66.6 and 83%, respectively (for a volumetric qunatification >1.5239), and of 60 and 100%, respectively (for a volumetric qunatification >1.762).

CONCLUSIONS

Our study showed that the volumetric quantification adds further informations to the routine evaluation for optimizing the selection of patients scheduled for endobronchial valve treatment.

[Bullectomy of giant bullae gave significant improvement of lung function]

A 49-year-old male smoker experienced acute deterioration of a progressive breathlessness. Spontaneous pneumothorax was diagnosed, and drainage was applied. Subsequent computed tomography revealed severe bilateral emphysematous bullae with right-sided predominance, and basal atelectasis. A lung function test showed severe obstructive disease. Right-sided bullectomy was performed through anterior thoracotomy with removal of giant bullae. Postoperative examination revealed markedly improved lung function and expansion of right-sided, previously consolidated lung tissue.

Pleural controversy: aetiology of pneumothorax

Pneumothoraces are classified as spontaneous, traumatic and iatrogenic. Spontaneous pneumothoraces that occur without recognized lung disease are termed primary spontaneous pneumothoraces (PSP), whereas those that occur due to an underlying lung disease are termed secondary spontaneous pneumothoraces. The aetiology of secondary, traumatic or iatrogenic pneumothoraces is not usually debated. However, the aetiology of PSP is potentially controversial and often debated. Therefore, PSP is the focus of this article. There are several purported causes, which include blebs, bullae, emphysema-like changes (ELC) and pleural porosity. The controversy is valid because of the importance of recurrence prevention. This article reviews the current available evidence for the causes of PSP. The causes of PSP are likely a combination ELC, pleural porosity and other potential factors.

[Respiratory management for a patient with a giant bulla and pulmonary dysfunction during off-pump coronary artery bypass grafting]

This case report describes a successful anesthetic management of a 74-year-old patient with a giant bulla and pulmonary dysfunction during off-pump coronary artery bypass grafting (OPCAB). BiPAP Vision with a laryngeal mask airway (LMA) was used for intraoperative respiratory management. General anesthesia was induced with propofol. After insertion of a LMA anesthesia was maintained with propofol and dexmedetomidine under spontaneous breathing with bilevel positive airway pressure. Epidural analgesia was used in combination with general anesthesia. The LMA was removed without coughing and bucking soon after the end of the surgery. There was no complication during and after anesthesia. This respiratory management may be beneficial for patients with a giant bulla and pulmonary dysfunction during OPCAB.

[A 49 year old male with a giant pulmonary bulla--a case report and review of the literature]

A 49 year old previously healthy smoker was diagnosed with a giant bulla in his right lung, following a history of dry cough, repeated upper airway infections and increasing dyspnea for several years. Computed tomography (CT) confirmed the presence of a giant bulla in the right inferior lobe and several smaller bullae in the right superior lobe. The giant bulla was 17 cm in diameter, occupying more than half of the right hemithorax. On spirometry a moderate restrictive and a mild obstructive pattern was observed. Lung volume was measured with two different techniques, nitrogen washout and plethysmography, with volume of the bullae estimated at 2.9 L, similar to the 3.2 L determined by CT. The patient underwent thoracotomy, where the giant bulla together with the inferior lobe were removed with lobectomy and the small bullae in the superior lobe with wedge resection. Five months postoperatively the patient is in good health and is back at work. Postoperatively significant improvements in spirometry values and lung volume measurements have been documented. This case demonstrates that giant bullae can be successfully managed with surgical resection and their size can be determined by different techniques, including lung volume measurements and chest CT.

Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy

BACKGROUND

The existing classifications for evaluating glaucoma filtering blebs rely mostly on external bleb characteristics and the postoperative control of intraocular pressure (IOP). Internal bleb structures are not carefully observed. This study aimed to analyze and compare glaucoma filtering bleb morphology using slit-lamp-adapted optical coherence tomography (SL-OCT) and ultrasound biomicroscopy (UBM), and to classify blebs according to results and intraocular pressure.

METHODS

We followed 29 eyes of 21 male patients and 40 eyes of 32 female patients who underwent glaucoma filtering surgery in Sixth People's Hospital of Shanghai, between 2002 and 2006. The blebs were imaged using SL-OCT and UBM and classified according to the intrableb morphology and control of IOP after surgery. A Fisher's exact test was used to compare the sensitivity for predicting a functioning bleb differed significantly between SL-OCT and UBM. A Fisher's exact test was also used for morphological analysis of the trabeculectomy blebs based on SL-OCT.

RESULTS

In the 69 eyes, there were 45 (65.2%) functioning blebs and 24 (34.8%) non-functioning blebs. We classified the blebs into four categories on the basis of SL-OCT images: diffuse, cystic, encapsulated and flat. Diffuse and cystic blebs were typically functional, whereas the other two types were always non-functional. The sensitivity of SL-OCT for predicting a functioning bleb was 92.7% (38/41 eyes) and specificity of predicting a non-functioning bleb was 83.3% (20/24 eyes). By contrast, sensitivity of UBM was 66.7% (30/45 eyes) and specificity was 75.0% (18/24 eyes). The sensitivity for predicting a functioning bleb differed significantly between the two techniques (P = 0.003).

CONCLUSIONS

SL-OCT provides high-axial-resolution images of anterior segment structures. The non-contact approach of SL-OCT enables visualization of intrableb structures at any time after surgery. SL-OCT has greater sensitivity and specificity than UBM in evaluating filtering bleb function. The morphological classification supported the assessment of bleb function and could provide objective data for evaluating the outcome of antiglaucoma surgery or the need for a second procedure.

Residual-limb skin temperature in transtibial sockets

The insulated environment of the lower-limb prosthesis can result in elevated residual-limb skin temperatures that may contribute to skin irritation, blistering, and a reduced quality of life. The design and materials of the prosthetic socket, suspension system, and liner can potentially alleviate these conditions, but the thermal load may vary with activity and location within the socket. To characterize the thermal environment at the skin-prosthesis interface, we made temperature measurements on five transtibial amputees at 14 locations on the residual limbs. After the participants donned their prosthesis and rested in the seated position for 15 min, the mean skin temperatures of their residual limbs increased by 0.8 degrees Celcius. Subsequent walking for 10 min resulted in a 1.7 degrees Celsius total increase in mean skin temperature. Thermal contour maps revealed the skin was coolest at the anterior proximal location and warmest across the posterior section, correlating with areas of low and high perfusion. From the results, we determined that residual-limb skin temperature depends on activity and locality. This information may aid in understanding where and why skin problems develop on lower-limb residual limbs and may provide design requirements for new prosthetic socket systems intended to alleviate temperature-related discomfort.

What's new in blistering disorders?

From the characterization of new animal models for the study of disease pathogenesis, to the demonstration of new therapeutic modalities, many developments have revolutionized the field of autoimmune bullous diseases in the past several years. This review highlights many of the significant advances that have taken place in the diagnosis, pathogenesis, and treatment options for pemphigus, pemphigoid, epidermolysis bullosa acquisita, and immunoglobulin (Ig) A-mediated bullous disorders.

Skin friction blistering: computer model

BACKGROUND/PURPOSE

Friction blisters, a common injury in sports and military operations, can adversely effect or even halt performance. Given its frequency and hazardous nature, recent research efforts appear limited. Blistering can be treated as a delamination phenomenon; similar issues in materials science have been extensively investigated in theory and experiment. An obstacle in studying blistering is the difficulty of conducting experiment on humans and animals. Computer modeling thus becomes a preferred tool.

METHOD

This paper used a dynamic non-linear finite-element model with a blister-characterized structure and contact algorithm for outer materials and blister roof to investigate the effects on deformation and stress of an existing blister by changing the friction coefficient and elastic modulus of the material in contact with the blister.

RESULTS

Through the dynamics mode and harmonic frequency approach, we demonstrated that the loading frequency leads to dramatic changes of displacement and stress in spite of otherwise similar loading. Our simulations show that an increased friction coefficient does not necessarily result in an increase in either the stress on the hot spot or blister deformation; local maximum friction stress and Von Mises stress exist for some friction coefficients over the wide range examined here. In addition, the stiffness of contact material on blistering is also investigated, and no significant effects on deformation and Von Mises stress are found, again at the range used. The model and method provided here may be useful for evaluating loading environments and contact materials in reducing blistering incidents.

CONCLUSION

The coupling finite-element model can predict the effects of friction coefficient and contacting materials&apos stiffness on blister deformation and hot spot stress.

Differential ventilation with spontaneous respiration for bilateral emphysema

In patients with bilateral bullous disease and empyema in one lung, controlled ventilation may be hazardous and result in severe hypoxia. A 50-year-old man with bullous disease and thoracic empyema on the left side was operated on under general anesthesia with spontaneous respiration using differential lung ventilation.

The relevance of the IgG subclass of autoantibodies for blister induction in autoimmune bullous skin diseases

Autoimmune bullous skin diseases are characterized by autoantibodies and T cells specific to structural proteins maintaining cell-cell and cell-matrix adhesion in the skin. Existing clinical and experimental evidence generally supports a pathogenic role of autoantibodies for blister formation. These autoantibodies belong to several IgG subclasses, which associate with different functional properties and may thus determine the pathogenic potential of IgG antibodies. In pemphigus diseases, binding of IgG to keratinocytes is sufficient to cause intraepidermal blisters without engaging innate immune effectors and IgG4 autoantibodies seem to mainly mediate acantholysis. In contrast, in most subepidermal autoimmune blistering diseases, complement activation and recruitment and activation of leukocytes by autoantibodies are required for blister induction. In these conditions, tissue damage is thought to be mainly mediated by IgG1, but not IgG4 autoantibodies. This review summarizes the current knowledge on the pathogenic relevance of the IgG subclass of autoantibodies for blister formation. Characterization of the pathogenically relevant subclass(es) of autoantibodies not only provides mechanistic insights, but should greatly facilitate the development of improved therapeutic modalities of autoimmune blistering diseases.

Searching for experimental models of Pemphigus vulgaris

The current knowledge on Pemphigus vulgaris (PV) pathophysiology suggests that blister formation relies on both PV IgG and non-IgG serum factors activity. PV autoimmunity seems to develop against both desmoglein 1/3 and acetylcholine receptors leading to transduction of signals to the cell mediated by phosphorilation events. Serum factors other than IgG also participate to PV acantholysis through apoptotic or cytokine-mediated mechanisms. Apart from the role played by each actor within the acantholysis, however, the current scenario arises important methodological issues. For example, the use of PV IgG or monoclonal anti-Dsg3 antibodies to experimentally reproduce the disease appears inadequate, as it does not take into account the role of non-IgG factors. On the basis of the above observations and those from our laboratories, here we propose that using whole sera from PV patients with active disease represents the most faithful manner to mimic the disease.

Early Results of Small-Incision Descemet’s Stripping and Automated Endothelial Keratoplasty

PURPOSE

To describe our technique and early results of Descemet's stripping and automated endothelial keratoplasty (DSAEK), identify perioperative complications, and discuss their management.

DESIGN

Prospective, noncomparative, surgical case series.

PARTICIPANTS

Twenty-six eyes of 26 patients who had corneal edema from Fuchs' endothelial dystrophy, pseudophakic bullous keratopathy, or aphakic bullous keratopathy.

INTERVENTION

The donor corneal lenticule was prepared using a microkeratome and an artificial anterior chamber maintainer. Stripping of the diseased host endothelium was performed under viscoelastic using a 2.75-mm clear corneal temporal incision. The incision was enlarged to approximately 4.2 mm to allow placement of a folded 8.5-mm-diameter donor corneal lenticule. The donor graft was positioned using a temporary air bubble that was partially evacuated after 7 minutes. The corneal wound was closed with a single 10-0 nylon suture.

MAIN OUTCOME MEASURES

Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction, keratometry, topographic astigmatism, corneal pachymetry, and perioperative complications.

RESULTS

Three months postoperatively, all donor grafts remained clear. The average 3-month postoperative BSCVA was 20/45 (range, 20/20-20/150). The average change in refractive astigmatism was 0.12+/-1.15 diopters (D) (range, -1.50 to 3.25). In patients who underwent simple DSAEK (i.e., no intraocular lens implantation), the average postoperative shift in spherical equivalent refractive error was 1.15+/-1.35 D (range, -0.25 to +4.25). Nine of 26 initial grafts dislocated postoperatively and had to be repositioned. Three of the repositioned grafts dislocated again and were replaced with new donor corneal lenticules, all of which remained clear.

CONCLUSIONS

Descemet's stripping and automated endothelial keratoplasty uses a mechanical microkeratome to harvest the donor corneal lenticule and mechanical stripping of the diseased host endothelium and Descemet's membrane. Despite a smooth graft-host interface, only 2 patients in the series achieved > or =20/25 vision. The average visual results were comparable to vision after deep lamellar endothelial keratoplasty. Although patients experienced excellent postoperative acuity with minimally induced surgical astigmatism, nearly one third of the donor lenticules needed to be either repositioned or replaced. Nevertheless, DSAEK offers significant advantages over standard penetrating keratoplasty for patients with Fuchs' dystrophy in pseudophakic bullous keratopathy.

Increased endothelin-1 and diminished nitric oxide levels in blister fluids of patients with intermediate cold type complex regional pain syndrome type 1

Background

In complex regional pain syndrome type 1 (CRPS1) pro-inflammatory mediators and vascular changes play an important role in the sustained development and outcome of the disease. The aim of this study was to determine the involvement of vasoactive substances endothelin-1 (ET-1) and nitric oxide (NO) during early chronic CRPS1.

Methods

Included were 29 patients with CRPS 1 who were diagnosed during the acute stage of their disease and observed during follow-up visits. Disease activity and impairment were determined and artificial suction blisters were made on the CRPS1 and the contralateral extremities for measurements of IL-6, TNF-α, ET-1 and nitrate/nitrite (NOx).

Results

The levels of IL-6, TNF-α and ET-1 in blister fluid in the CRPS1 extremity versus the contralateral extremity were significantly increased and correlated with each other, whereas NOx levels were decreased.

Conclusion

The NOx/ET-1 ratio appears to be disturbed in the intermediate stage of CRPS, resulting in vasoconstriction and consequently in a diminished tissue blood distribution.

Long-term intraocular pressure control of eyes that developed encapsulated blebs following trabeculectomy

PURPOSE

To evaluate the long-term intraocular pressure (IOP) control of eyes that developed an encapsulated bleb (EB) following trabeculectomy.

METHODS

Between 1994 and 1995, 25 eyes developed EBs and were randomized to medical treatment or needling without adjunct antimetabolites. Among the 25 patients who developed an EB, 21 were followed for at least 6 months. A control group of 21 consecutive eyes, which underwent trabeculectomy during the same period and that did not develop EBs was retrospectively selected. Success was defined as IOP <21 mmHg with or without medications. Kaplan-Meier survival analysis was performed to compare the groups.

RESULTS

Among the 21 eyes that developed EBs, 12 (57%) had undergone transconjunctival needling and nine (43%) had received medical treatment. Mean follow-ups were 30.0 +/- 14.0 months, 33.3 +/- 18.5 months, and 37.4 +/- 2.6 months for the needling, medical treatment, and control groups, respectively (P = 0.19). Kaplan-Meier survival curves demonstrated that the control group showed a significantly lower chance of failure than both the needling and the medical treatment groups (P < 0.0001).

CONCLUSION

Encapsulated blebs may be associated with an increased risk for surgical failure.

A new technology for reducing shear and friction forces on the skin: implications for blister care in the wilderness setting

OBJECTIVE

It is well known that physical trauma to skin caused by repetitive friction is a primary component of blister formation. Although friction blisters in a wilderness setting particularly occur on the feet and ankles, they often form on the hands and fingers during such activities as white-water rafting, kayaking, and canoeing. These blisters are often incapacitating and can have disabling consequences. This article describes laboratory and clinical experiments testing the efficacy of a new bandage technology in reducing shear and friction forces on the skin.

METHODS

A custom-made apparatus was used in a laboratory setting to measure and compare the surface coefficient of friction of 11 bandages. In addition, a controlled clinical study was conducted on 15 healthy, able-bodied female subjects (mean age 35 years), where the same apparatus was used to measure the coefficient of friction of the skin over the medial tibial cortex with and without the new technology device in place.

RESULTS

This laboratory study demonstrated the new device to have the lowest surface coefficient of friction of any bandage tested (0.57). For example, the common product Moleskin was 21% higher (0.67), with all other products testing at least 64% higher (>0.94). In the clinical study, the new technology device reduced the coefficient of friction on the skin by 31% (0.225 vs. 0.327), and this difference was statistically significant (P < .001).

CONCLUSIONS

A bandage containing a new technology demonstrated the lowest surface coefficient of friction of any bandage tested. In addition, clinical tests performed with the same bandage demonstrated significant reduction of the coefficient of friction on the skin.

A case of bullous tinea pedis with dermatophytid reaction caused by Trichophyton violaceum

Summary The authors report a case of bullous tinea pedis caused by Trichophyton violaceum with dermatophytid reaction in a 26-year-old woman who had been in Africa. Diagnosis was based on mycological examination (direct microscope observation and culture). Recovery was achieved after systemic antimycotic therapy with itraconazole and topical imidazole for a month.

Hostile marital interactions, proinflammatory cytokine production, and wound healing

CONTEXT

A growing epidemiological literature has suggested that marital discord is a risk factor for morbidity and mortality. In addition, depression and stress are associated with enhanced production of proinflammatory cytokines that influence a spectrum of conditions associated with aging.

OBJECTIVE

To assess how hostile marital behaviors modulate wound healing, as well as local and systemic proinflammatory cytokine production.

DESIGN AND SETTING

Couples were admitted twice to a hospital research unit for 24 hours in a crossover trial. Wound healing was assessed daily following research unit discharge.

PARTICIPANTS

Volunteer sample of 42 healthy married couples, aged 22 to 77 years (mean [SD], 37.04 [13.05]), married a mean (SD) of 12.55 (11.01) years.

INTERVENTIONS

During the first research unit admission, couples had a structured social support interaction, and during the second admission, they discussed a marital disagreement.

MAIN OUTCOME MEASURES

Couples' interpersonal behavior, wound healing, and local and systemic changes in proinflammatory cytokine production were assessed during each research unit admission.

RESULTS

Couples' blister wounds healed more slowly and local cytokine production (IL-6, tumor necrosis factor alpha, and IL-1beta) was lower at wound sites following marital conflicts than after social support interactions. Couples who demonstrated consistently higher levels of hostile behaviors across both their interactions healed at 60% of the rate of low-hostile couples. High-hostile couples also produced relatively larger increases in plasma IL-6 and tumor necrosis factor alpha values the morning after a conflict than after a social support interaction compared with low-hostile couples.

CONCLUSIONS

These data provide further mechanistic evidence of the sensitivity of wound healing to everyday stressors. Moreover, more frequent and amplified increases in proinflammatory cytokine levels could accelerate a range of age-related diseases. Thus, these data also provide a window on the pathways through which hostile or abrasive relationships affect physiological functioning and health.

Bullous emphysema versus diffuse emphysema: a functional and radiologic comparison

The contribution of bullous emphysema (BE) to the functional impairment of patients with concomitant diffuse emphysema (DE) and the confounding effects of BE on functional measurements were investigated. Twenty-nine patients (Group I), with BE and DE were compared with a group of patients without BE matched, among other criteria, for radiographic extent of DE (Group II). Group I showed significantly lower PaO2, FEV1 and DLCO values and higher MRC score than Group II. In Group I the radiographic extent of BE and the extent of DE did not predict the functional impairment. The FEV1/FVC ratio in the subgroup with BE extent > 25% of total lung volume was higher than in subgroups with BE extent > 20% and 15%, respectively. In the same subgroups the correlation between DE and DLCO increased with the extent of BE. We conclude that BE contributes to the functional impairment of patients with concomitant DE. The confounding functional effect of bullae depends on BE extent: relatively milder obstruction can be observed with severe BE, whereas moderate BE causes modest deterioration of diffusing capacity, explaining the lack of functional-radiologic correlations in Group I. Therefore the computed tomographic scan is very useful in the work-up of BE with DE associated.

Effect of jaundice and its resolution on wound re-epithelization, skin collagen synthesis, and serum collagen propeptide levels in patients with neoplastic pancreaticobiliary obstruction

BACKGROUND

Wound and anastomotic healing is considered to be delayed in patients with obstructive jaundice. The study was designed to find out whether the healing of experimental suction blister wounds, skin collagen synthesis, and serum procollagen levels are affected by obstructive jaundice, and if biliary drainage may cause any alterations in these processes.

PATIENTS AND METHODS

Suction blisters were induced on 24 patients with obstructive jaundice caused by neoplastic pancreaticobiliary obstruction and 17 control patients with the corresponding condition without jaundice, to compare healing parameters and collagen synthesis between the groups. A second set of suction blisters were induced on 13 formerly jaundiced patients after the resolution of jaundice and on 14 control patients, to find out whether drainage or time modifies healing or collagen synthesis. By using this model, it is possible to evaluate the re-epithelization and inflammation on wound healing and to assess the baseline skin collagen synthesis. The healing of suction blisters was followed up by measuring water evaporation and blood flow in the wound. Blister fluids and serum samples were collected to study collagen propeptides.

RESULTS

Healing of the blister wound was unaffected by obstructive jaundice. Drainage had no effect on healing. The baseline synthesis of type I and type III collagen in the skin was decreased in jaundiced patients. Biliary drainage improved the synthesis. Serum type III procollagen propeptide levels were elevated in jaundiced patients, but began to normalize after drainage.

CONCLUSION

Healing of an experimental blister wound is not disturbed by obstructive jaundice. The decreased baseline skin collagen synthesis is partly restored by the resolution of jaundice. The results indicate that cell protein synthesis is disturbed earlier than cell dynamics in obstructive jaundice. The elevated serum PIIINP levels, which are most likely to be related to early fibrosis in liver, decreased after drainage.

Inherited junctional epidermolysis bullosa in the German Pointer: establishment of a large animal model

Junctional epidermolysis bullosa (JEB) is a genodermatosis suitable for gene therapy because conventional treatments are ineffective. Here, we elucidate the genetic basis of mild JEB in a breed of dogs that display all the clinical traits observed in JEB patients. The condition is associated with reduced expression of laminin 5 caused by a homozygous insertion (4818+207ins6.5 kb) of repetitive satellite DNA within intron 35 of the gene (lama3) for the laminin alpha3 chain. The intronic mutation interferes with maturation of the alpha3 pre-messenger RNA resulting in the coexpression of a transcript with a 227 nucleotide insertion and a wild-type mRNA that encodes scant amounts of the alpha3 polypeptide. Our results show that the amino acid sequence and structure of the canine and human alpha3 chain are highly conserved and that the reduced expression of laminin 5 affects the adhesion and clonogenic potential of the JEB keratinocytes. These JEB dogs provide the opportunity to perform gene delivery in a naturally occurring genodermatosis and to evaluate host tolerance to recombinant laminin 5.

Avancées moléculaires dans la physiopathologie des maladies bulleuses autoimmunes

Autoimmune blistering skin diseases are characterized by the production of autoantibodies directed against adhesive structures of the skin. These organ specific autoimmune diseases included pemphigus in which autoantibodies target proteins of the desmosomal complex, and subepidermal autoimmune diseases characterized by autoantibodies directed against structural proteins of the dermoepidermal junction. Binding of autoantibodies to their targets induces a loss of adhesion between keratinocytes in pemphigus and alterations of the dermoepidermal junction in subepidermal autoimmune diseases. Progresses during the last twenty years had allowed the identification of target autoantigens and the characterization of their adhesive functions, a better understanding of the pathogenesis of these diseases and the development of new diagnostic tools.

Breast blisters in groups of slow-growing broilers in relation to strain and the availability and use of perches

1. The relationship between perching behaviour, availability of perches and the incidence and severity of breast blisters in broilers was investigated together with a comparison between two slow-growing broiler strains. 2. Sixteen single strain groups (n = 60) of Labresse and i657 broilers were subjected throughout the experiment to one of three perch availabilities: 15 cm per bird (Labresse and i657), 7.5 cm per bird (i657 only), and 0 cm per bird (i657 only) with 4 replicates per treatment. The birds were housed indoors from one day old, and at 43 d of age 52 birds from each group were moved to outdoor housing facilities with access to grass-covered outdoor areas until slaughter at 84 d of age. 3. The use of perches was monitored via video recordings throughout the experimental period. The severity of breast blisters was recorded on a scale from 0 to 2 at slaughter. 4. Groups of i657 with 15 cm perch per bird used these more than groups with 7.5 cm perch per bird (19% vs 8% of birds perching at midnight). A positive association between access to perches and severe breast blisters (score 2) was found in the groups of i657, with odds ratios of 3.1 and 3.4 for 7.5 and 15.0 cm per bird, respectively, relative to the no-perch treatment. 5. Labresse were more likely to develop breast blisters than i657 (odds ratio 3.5), but used the perches less (0.1 vs 9.5 birds perching at midnight) and weighed less (2011 g vs 2246 g) than i657. 6. Males had a higher incidence of breast blisters than females (odds ratio 12.2), and this was most prominent in the Labresse strain (odds ratio 40.0). 7. In some broiler strains access to perches may be associated with an increase in the occurrence of severe breast blisters, but strain and sex of broiler chickens appear to have a much larger influence than access to perches on the incidence of breast blisters.

The miscellaneous blistering disorders

Historically, the classification of the blistering disorders has been arbitrarily assigned by common clinical features (ie, vesicle, bullae), etiologic factors (ie, infectious, immunologic), or histologic parameters (ie, intraepidermal and subepidermal). There are distinct advantages to each of these classification systems, yet there remain a small number of either common conditions that rarely manifests as a blistering disorder or uncommon conditions that routinely blister, defying conventional classification. Such misfits comprise a miscellaneous group of blistering conditions that merit special consideration.

Solar-Simulated Ultraviolet Radiation-Induced Upregulation of the Melanocortin-1 Receptor, Proopiomelanocortin, and α-Melanocyte-Stimulating Hormone in Human Epidermis In Vivo

Ultraviolet light is one of the most crucial environmental factors with regard to its capacity to induce skin cancer, premature aging of the skin, and immunosuppression. Although ultraviolet directly affects the function of epidermal cells, many of these effects are mediated by induction of cytokines, growth factors, and neuropeptides, such as alpha-melanocyte-stimulating hormone. Recently, in addition to its well-known pigmentation inducing activity, a strong anti-inflammatory as well as an immunomodulatory potential of alpha-melanocyte-stimulating hormone has been recognized. The aim of this study was to determine, whether ultraviolet irradiation affects the expression of both alpha-melanocyte-stimulating hormone and the melanocortin-1 receptor in human epidermis in vivo. The volar aspects of the forearms were exposed to twice the minimal erythema dose of solar-simulating radiation. Three, 6, and 24 h after irradiation, the proopiomelanocortin and interleukin-10 mRNA levels in suction blister induced epidermal sheets were considerably upregulated as detected by semiquantitative reverse transcription-polymerase chain reaction. Furthermore, alpha-melanocyte-stimulating hormone and interleukin-10 protein levels in blister fluids were significantly increased 24 h after ultraviolet irradiation, an effect that could be abolished by application of the broad-spectrum sunscreen Anthélios XL prior to ultraviolet (solar-simulating radiation) exposure. In addition, enhanced melanocortin-1 receptor mRNA and receptor protein expression upon solar-simulating radiation was ascertained by reverse transcription-polymerase chain reaction and immunohistochemistry of the epidermal sheets, respectively. Proopiomelanocortin-derived neuropeptides, such as alpha-melanocyte-stimulating hormone may therefore play an important part in modulating ultraviolet-induced inflammation.

Targeted inactivation of murine laminin gamma2-chain gene recapitulates human junctional epidermolysis bullosa

Junctional forms of epidermolysis bullosa (JEB) are associated with mutations in six distinct genes expressed in the cutaneous basement membrane zone; these include LAMA3, LAMB3, and LAMC2, which encode laminin 5 subunit polypeptides, the alpha3-, beta3-, and gamma2-chains, respectively. Here we generated a mouse model for JEB by inactivating the laminin gamma2-chain gene by targeted frameshift deletion of exon 8 in Lamc2. Heterozygous mice were phenotypically normal, whereas the majority of Lamc2-/- mice showed blistering phenotype on days 1 to 2 and died within 5 days of birth. The Lamc2-/- mice demonstrated absent expression of laminin gamma2-chain on the basement membrane zone as well as attenuated expression of alpha3- and beta3-chains of laminin. Transmission electron microscopy revealed rudimentary, poorly developed hemidesmosomes. The epidermis of the Lamc2-/- mice revealed induced apoptosis in the basal cells of the blistered skin, suggesting that cell-matrix adhesion provided by laminin 5 plays a role in cell survival in vivo. Cultured Lamc2-/- keratinocytes demonstrated slightly positive staining with gamma2-chain-specific antibodies, which could be explained by the presence of a transcript with partial restoration of the reading frame owing to alternative splicing in vitro. These cells proliferated in different matrices and attached to type IV collagen and Matrigel as efficiently as the wild-type keratinocytes, whereas their attachment on plastic and laminin was significantly weaker. In summary, Lamc2-/- mouse recapitulates human JEB and provides novel insight into the role of laminin 5 in keratinocyte biology.

Plectin-isoform-specific rescue of hemidesmosomal defects in plectin (-/-) keratinocytes

The various plectin isoforms are among the major crosslinking elements of the cytoskeleton. The importance of plectin in epithelia is convincingly supported by the severe skin blistering observed in plectin-deficient humans and mice. Here, we identified plectin 1a (> 500 kDa), a full length plectin variant containing the sequence encoded by the alternative first exon 1a, as the isoform most prominently expressed in human and mouse keratinocytes. In skin sections and cultured keratinocytes, plectin 1a was shown to colocalize with hemidesmosomal structures. In contrast, a second isoform expressed in epithelia, plectin 1c, differing from 1a merely by a short N-terminal sequence, colocalized with microtubules. Expression of plectin 1a, but not of its N-terminal fragment alone, or of a third alternative full length isoform (plectin 1), restored the reduced number of hemidesmosome-like stable anchoring contacts in cultured plectin-null keratinocytes. Our results show for the first time that different isoforms of a cytolinker protein expressed in one cell type perform distinct functions. Moreover, the identification of plectin 1a as the isoform defects in which cause skin blistering in plectin-related genetic diseases, such as epidermolysis bullosa simplex MD and epidermolysis bullosa simplex Ogna, could have implications for the future development of clinical therapies for patients.

Managing blisters in competitive athletes

Friction blisters can have a negative effect on an individual's ability to perform his or her sport or duties. In a recent study, 69% of soldiers participating in a 20-km road march were found to have blisters, 10% of whom required medical intervention. Blistering of the feet is one of the most common injuries sustained by runners while training and racing. Although most blisters are minor and can be treated conservatively, others can lead to intense pain, cellulitis, and even sepsis. The best way to treat friction blisters is to prevent them; however, if they do occur, timely and effective treatment will help prevent the complications that can impede athletic performance.