Civilian and military doctors' knowledge of tranexamic acid (TXA) use in major trauma: a comparison study.

INTRODUCTION: Tranexamic acid (TXA) administration within the recommended time of 3 hours has been demonstrated to improve outcomes following trauma. The aim of this study was to identify potential knowledge gaps in the administration of TXA in order to target further educational training in those doctors responsible for the management of acute trauma. METHODS: 104 military and 852 civilian doctors were invited to complete a four-item web-based questionnaire pertaining to the indications, dose, side effects and evidence base for TXA administration in trauma. Doctors of all grades and surgical specialties including emergency trainees and anaesthetics were surveyed. RESULTS: 65 military and 460 civilian doctors responded with a response rate of 62% and 54%, respectively. Responses were required for every question to allow progression and submission. 93% of military doctors knew the initial dose of TXA compared with 34% of civilian doctors. The Clinical randomisation of an Antifibrinolytic in Significant Haemorrhage (CRASH) 2 trial was known to 91% of military doctors compared with 24% of civilian doctors. The optimal time for delivery of TXA in under 3 hours was correctly identified by 91% of military doctors compared with 10% by civilian doctors. DISCUSSION: Military doctors are more familiar with TXA and its side effect profile. Given the potential impact of TXA on patient outcome and the findings of this study, further education of all doctors is recommended including dose, timing and potential side effects.

Pre-operative gastric emptying time correlates with clinical response to gastric electrical stimulation in the treatment of gastroparesis.

BACKGROUND: Gastric electrical stimulation (GES) may be of benefit in cases of gastroparesis that fail to respond to standard medical therapy. Response to this treatment is varied and prediction of clinical improvement is difficult. METHODS: This was a retrospective review and symptom questionnaire survey for all patients who underwent GES insertion in a single institution from November 2008 until May 2010 using the gastroparesis cardinal symptom index (GCSI). RESULTS: 14 out of 17 patients who had GES insertion responded to telephone or postal questionnaire. Mean pre-operative gastric emptying time was 151 min (median 146 min, range 18-318). Median follow up was 14 months (range 7-25 months). The mean reduction in GCSI score after GES insertion was 51% (13.4 vs 6.4, Z = 0.0013). Percentage reduction in GCSI correlated with pre-operative solid gastric emptying time (p = 0.0086). Two patients who responded to questionnaire required device removal, one due to a gastric perforation and the other for discomfort related to the implant and a poor clinical response. CONCLUSIONS: GES significantly improves symptoms of gastroparesis on the GCSI score. Not all patients respond equally to GES, and response may be predicted by pre-operative solid gastric emptying times.

Generational and occupational differences in human factors knowledge and awareness: a comparison study.

INTRODUCTION: Increasing healthcare sector litigation, accountability and governance has resulted in the identification of human factors (HF) as a common source of error. Both NHS and military doctors must have awareness of HF to enhance safety and productivity. There is limited published evidence examining knowledge of HF in these two healthcare professional groups. METHODS: Doctors of all grades and specialties across the NHS and 3 military groups including the Defence Deanery within the UK were invited to complete a 10-item web-based survey. Questions focused on training undertaken, HF knowledge and potential future training needs. RESULTS: The survey link was emailed to 250 military and 1400 NHS doctors, 191 military and 776 NHS responded (response rate: 76% and 55%, respectively). Military doctors above foundation trainees are more familiar with HF, have had more training and recognise a requirement for additional training. Military foundation trainees had similar responses to their NHS colleagues. Doctors who had not undertaken any HF training are less likely to appreciate its value, with almost 60% of senior NHS doctors reporting no training. Foundation trainees have more training in HF than their senior peers when military seniors are excluded and more frequently identified a need for further training. Junior doctors identified stress, fatigue, communication and leadership more frequently, with seniors identifying work environment and music in theatre correctly more often. CONCLUSION: Non-training grade doctors are less likely to seek HF training. Military doctors are more familiar with HF and have undertaken more training. Given the role of HF in communication, human error, potential litigation, stress, conflict and gross negligence manslaughter convictions, further education is vital.

Does using the WHO surgical checklist improve compliance to venous thromboembolism prophylaxis guidelines?

BACKGROUND: Using the World Health Organisation (WHO) surgical checklist has been shown to improve the safety of patients undergoing surgery. Its effect on the compliance to venous thromboembolism (VTE) guidelines has not been established before. Our objective was to assess if using the WHO checklist improved compliance to VTE prophylaxis guidelines. METHODS: Compliance to NICE VTE guidelines were prospectively assessed in all general surgery patients over two separate audit periods, before and after 6 months of the routine use of the WHO checklist. Correct completion of the checklist was verified. RESULTS: 370 patients (173 [47%] male, 197 [53%] female, mean age 61.6 yrs). Non compliance to NICE VTE guidelines was reduced form 16/233 (6.9%) to 3/137 (2.1%) after introduction of the checklist (p = 0.046 Fisher exact test). Non compliance was reduced in both emergency and elective procedures. CONCLUSIONS: Establishment of the WHO checklist for routine use in all general surgery patients may significantly improve VTE guideline compliance of all general surgery patients.

Malignant T cells in cutaneous T-cell lymphoma lesions contain decreased levels of the antiapoptotic protein Ku70.

BACKGROUND: Malignant T cells in primary cutaneous T-cell lymphoma (CTCL) are genetically unstable and exhibit prolonged lifespans potentially explained by dysregulation of apoptosis, yet are responsive to apoptosis-inducing therapies. The heterodimeric protein Ku70/80 is known to play a role in DNA repair (Ku70 and Ku80) and inhibition of apoptosis (Ku70 only). OBJECTIVES: To investigate the expression of Ku70/80 in CD3+ T cells derived from skin and blood in patients with CTCL and normal samples, as well as benign dermatoses. METHODS: Normal (n=10), CTCL (n=9) and benign dermatoses (n=13) skin samples were stained for confocal imaging of Ku70/80 and CD3 and analysed using imaging software. Circulating CD4+ T cells in normal and CTCL peripheral blood were analysed by flow cytometry and Western blot for Ku70/80 expression (n=6). RESULTS: Ku70 and Ku80 were significantly diminished in T cells of CTCL lesions relative to T cells of control skin. Decreased T-cell Ku70 expression was not a feature of the benign dermatoses psoriasis and contact dermatitis, suggesting that loss of Ku70/80 in CTCL is not simply the result of cutaneous inflammation. Reduced Ku70 was also noted in circulating CD4+ T cells in patients with CTCL with peripheral blood involvement. CONCLUSIONS: Deficient expression or lack of Ku70/80 may result in genomic instability and play a role in tumorigenesis, as well as account for the increased susceptibility of malignant T cells to apoptosis-inducing treatment modalities in the setting of intrinsic resistance to apoptosis.

Avoidance of tattoo disruption: a further benefit of laparoscopic surgery.

INTRODUCTION: Tattoos are increasingly common in both male and female patients. Abdominal skin tattoos may be present at the site of proposed incisions for conventional surgery whereas laparoscopic port site placement can be adjusted to accommodate tattoo constraints. METHODS: Patients with tattoos were questioned by face-to-face interview to determine how long ago they had their tattoo, financial cost of the tattoo, and potential degree of distress caused by disruption of their tattoo (on a scale of 1-10). Consultant and higher surgical trainee general surgeons were asked by e-mail survey whether they had encountered a patient with a tattoo at the site of a proposed incision, did they avoid incising the tattoo during surgical intervention, and had they received a complaint from a patient about tattoo distortion. RESULTS: Ninety six patients (50 male, median age 29 years) were questioned. Median cost of the tattoos was pound35 ($70). Female patients were more likely to be distressed and complain than men about tattoo disruption (p = 0.0003) and there was a significant inverse correlation between time from tattooing and distress (p = 0.02). Most (79%) of the general surgeons questioned (n = 107, response rate 82%) had encountered tattoos at proposed incision sites; 61% had avoided making an incision through it and 4% had received a complaint about tattoo disruption by a patient. CONCLUSION: Tattoo disruption by surgical incision may cause distress especially in female patients who had their tattoo recently. Tattoos should be avoided where possible by alternative port site placement.

Day-case laparoscopic Nissen fundoplication.

INTRODUCTION: Nissen fundoplication has been performed laparoscopically for over 15 years, being associated with shorter hospital stay and fewer complications than conventional open surgery with good long-term outcomes. Day-case laparoscopic Nissen fundoplication (LNF) is rarely performed in the UK and most series in the literature report length of stay >2 days. METHODS: The objective of this study was to examine the safety and efficacy of day-case LNF. The clinical records of all patients undergoing LNF under the care of three surgeons in a district general hospital (DGH) during a 5-year period (January 2003 to December 2007) were reviewed to examine length of stay, complications, length of procedure, grade of operating surgeon and symptoms on follow-up. RESULTS: One hundred thirteen day-case LNFs were recorded in this series. Day-case LNF patients had median age of 45 years (range 20-68 years, 65% (64.6%) male) and 98% were American Society of Anesthesiologists (ASA) grade I or II. Twenty-one cases (19%) were performed by higher surgical trainees. Median operative time was 54 minutes (range 25-120 min). Only one perioperative complication (port-site bleed) occurred, treated without prolonging length of stay. The proportion of all LNF performed as day cases increased from 8% to 52% during the study period. Median operative time has significantly reduced from the first 20 consecutive LNF cases to the latest 20 cases [65 min (range 40-120 min) versus 48 min (range 25-72 min); p = 0.037]. At follow-up (median 7 weeks, range 2-31 weeks) 82% of patients had improvement in all presenting symptoms. Eight patients had postoperative complications [wound infection (n = 2), persistent regurgitation requiring laparoscopic division of a gastric band adhesion (n = 1), dysphagia (n = 5 with two patients requiring redo partial fundoplication and one patient requiring dilatation) and there were no conversions to open surgery. CONCLUSION: Day-case LNF is safe and effective for treating selected patients with gastroesophageal reflux disease (GERD) in a DGH. The proportion of day-case LNFs is increasing in our unit. Half of the LNFs in a DGH can be done as day cases. Experience is associated with a significant reduction in operative time.

The carbon footprint of laparoscopic surgery: should we offset?

The aim of this study was to estimate the effect that the expansion of laparoscopic surgery has had on global warming. Laparoscopic procedures performed in a hospital over a 10-year period were analysed. The number of CO(2) cylinders (size C) used over a 2.5-year period and the "carbon footprint" of each cylinder was calculated. There was a fourfold increase of in the number of laparoscopic procedures performed over the past 10 years (n = 174-688). Median operative time for the laparoscopic procedures performed over the past 2.5-years (n = 1629) was 1.01 h (range 0.3-4.45 h) with 415 cylinders used in this period giving an operative time per cylinder of 3.96 h. Each cylinder produces only 0.0009 of tonnes of CO(2). Despite increasing frequency of the laparoscopic approach in general surgery, its impact on global warming is negligible.

Day case emergency laparoscopic appendectomy.

BACKGROUND: Laparoscopic appendectomy (LA) is associated with a shorter hospital stay and fewer complications than conventional open appendectomy (OA). This study aimed to examine the safety and efficacy of day case emergency LA. METHODS: The records of patients undergoing emergency LA under the care of two laparoscopic surgeons over a 3-year period (Februrary 2003 to February 2006) were reviewed to examine hospital length of stay (LOS), complications, histology, grade of the operating surgeon, and time required to perform the procedure. RESULTS: A total of 104 patients (median age, 25 years; range, 11-72 years; 58 men) underwent LA, with 9 and 66 patients discharged in 8 and 24 hours, respectively (median LOS 22 hours: range 6-170 hours). One patient underwent conversion to OA. Histologically, 86 patients had appendicitis and 18 had normal appendices with another pathology present. The median operative time was 35 min (range, 20-80 min). The complications included three wound infections and two pelvic abscesses not requiring further operative intervention. CONCLUSION: Day case emergency LA is safe and effective for treating selected patients.

T cells reactive to a single immunodominant self-restricted allopeptide induce skin graft rejection in mice.

Alloreactive T lymphocytes can respond to foreign MHC complexed with foreign peptides through the direct pathway of allorecognition and can additionally recognize allopeptides expressed in the context of recipient (self) MHC through the indirect pathway. To better elucidate how indirect pathway-responsive CD4(+) T cells mediate allograft rejection, we isolated and characterized a TH1 T cell line from BALB/c recipients of B10.A skin that responds to a defined immunodominant, self-restricted allopeptide, I-Abetak58-71. When transferred into BALB/c severe combined immunodeficiency recipients of B10.A skin allografts, this cell line specifically induced a form of skin graft rejection characterized by the presence of TH1 cytokines, macrophage infiltration, and extensive fibrosis. Recall immune responses and immunofluorescence of the rejecting skin revealed only the presence of the peptide-specific T cells within the recipient animals, with no evidence of a direct pathway alloresponse. These studies demonstrate that T cells reactive to a single self-restricted allopeptide can mediate a form of allogeneic skin graft rejection that exhibits characteristics of a chronic, fibrosing process.

The effect of jaundice on the generation of anti-gastrin antibodies in G17DT immunized patients with advanced pancreatic cancer.

AIM: The aim of this study was to determine the ability of G17DT to generate anti-gastrin antibodies in jaundiced patients with biliary obstruction due to advanced pancreatic cancer. METHODS: G17DT was administered to 41 patients with advanced pancreatic adenocarcinoma by intramuscular (i.m.) injection at a dose of 250mcg at weeks 0, 1 and 3 of the study. RESULTS: Thirty-five of 41 patients participating in the study were categorized as responders in terms of their gastrin-17 antibody response. There was no correlation between the maximum G17 antibody response and the bilirubin level at either week 0 or week 12. The median survival of patients from the time of the first injection of G17DT was 204 days with 25% of patients surviving for or=305 days. CONCLUSION: This study shows that G17DT administered to jaundiced patients with advanced pancreatic cancer is immunogenic and well tolerated.

Antibiotic regimens for secondary peritonitis of gastrointestinal origin in adults.

BACKGROUND: Secondary peritonitis is associated with a high mortality rate and if not treated successfully leads to development of abscesses, severe sepsis and multi-organ failure. Source control and adjunctive antibiotics are the mainstay of treatment. However, no conclusive evidence suggest that one antibiotic regimen is better than any other but at the same time have a lower toxicity. OBJECTIVES: To ascertain the efficacy and adverse effects of different antibiotic regimens in treating intra-abdominal infections in adults. Outcomes were divided into primary (clinical success and effectiveness in reducing mortality) and secondary (microbiological success, preventing wound infection, intra-abdominal abscess, clinical sepsis, remote infection, superinfection, adverse reactions, duration of treatment required, effectiveness in reducing hospitalised stay, and time to defervescence). SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 4, 2004), MEDLINE (from 1966 to November 2004), EMBASE (from 1980 to November 2004) and Cochrane Colorectal Cancer Group specialised register SR-COLOCA. Bibliographies of identified studies were screened for further relevant trials. SELECTION CRITERIA: Randomised and quasi-randomised controlled trials comparing different antibiotic regimens in the treatment of secondary peritonitis in adults were selected. Trials reporting gynaecological or traumatic peritonitis were excluded from this review. Ambiguity regarding suitability of trials were discussed among the review team. DATA COLLECTION AND ANALYSIS: Six reviewers independently assessed trial quality and extracted data. Data collection was standardised using data collection form to ensure uniformity among reviewers. Statistical analyses were performed using the random effects model and the results expressed as odds ratio for dichotomous outcomes, or weight mean difference for continuous data with 95% confidence intervals. MAIN RESULTS: Fourty studies with 5094 patients met the inclusion criteria. Sixteen different comparative antibiotic regimens were reported. All antibiotics showed equivocal comparability in terms of clinical success. Mortality did not differ between the regimens. Despite the potential high toxicity profile of regimens using aminoglycosides, this was not demonstrated in this review. The reason for this could be the inherent bias within clinical trials in the form of patient selection and stringency in monitoring drug levels. AUTHORS' CONCLUSIONS: No specific recommendations can be made for the first line treatment of secondary peritonitis in adults with antibiotics, as all regimens showed equivocal efficacy. Other factors such as local guidelines and preferences, ease of administration, costs and availability must therefore be taken into consideration in deciding the antibiotic regimen of choice. Future trials should attempt to stratify patients and perform intention-to-treat analysis to allow better external validity.

Day-case breast cancer axillary surgery.

INTRODUCTION: The standard locoregional management of breast cancer is excision of the primary tumour and axillary staging with suction drainage of the axilla. The objective of this study was to determine the safety, tolerability and efficacy of day-case surgery without suction drainage. PATIENTS AND METHODS: A review of complete, prospectively collected data was performed on all breast cancer patients (screening and symptomatic) planned to undergo day-case axillary surgery at a University Teaching Hospital between 2000 and 2002. Postoperative complications were recorded and the notes of patients not discharged on the day of their surgery were also examined to establish the reason for overnight stay. RESULTS: 165 patients underwent intended day-case axillary surgery (axillary dissection level 1/2; median age, 55 years; range, 39-76 years). Of these, 16 (9.7%) were admitted overnight usually due to over-running of theatre lists (n = 13; 81%). 29 patients (17.6%) underwent axillary dissection alone, the remainder had axillary surgery combined with wide local excision (median number of lymph nodes excised 11; range, 2-18). Complications included symptomatic seroma formation in 37 patients (22%) and wound infection in 16 patients (10%). CONCLUSIONS: Day-case axillary surgery can be performed safely with surgical morbidity comparing favourably to published work of 'traditional' axillary drainage following lymphadenectomy.

Routine versus selective histological examination after cholecystectomy to exclude incidental gallbladder carcinoma.

Introduction Gallstone disease is treated commonly with cholecystectomy. Malignant disease of the gallbladder may present similarly and has a poor prognosis. It is common for cholecystectomy specimens to be sent for histological examination to exclude malignancy. However, the incidence of incidental gallbladder carcinoma (IGBC) is low and it has therefore been suggested that macroscopic inspection of the gallbladder by the surgeon, followed by selective histological examination of abnormal specimens, may be safe and cost saving. Methods All cholecystectomies performed between 1 May 2003 and 1 September 2009 were identified from clinical coding. Pathology records were used to identify gallbladder malignancies; these were searched manually to identify IGBC. Pathology reports and case notes were cross-referenced to determine whether there were macroscopic abnormalities present. Annual cost savings were estimated by comparing the number of gallbladder specimens over one year (May 2013 - April 2014) with the total number of cholecystectomies performed in that time. Results Of 4,776 cholecystectomies identified, 12 (0.25%) were cases of IGBC. These cases had a higher median age (68 vs 54 years, p<0.001) and a higher proportion were emergency operations (50% vs 12%, p<0.001). All cases had some form of macroscopic abnormality, most commonly wall thickening (n=6, 50%). Only two cases (17%) had a visible tumour present. Conclusions All cases of IGBC in this study had a macroscopically abnormal gallbladder. Our findings suggest it is safe to adopt a selective approach to histological examination. Savings of almost £20,500 per annum have been achieved.

Apoptosis is the predominant form of epithelial target cell injury in acute experimental graft-versus-host disease.

Cutaneous and mucosal epithelial cells are primary targets of injury in acute graft-versus-host disease (GVHD), the principal complication of allogeneic bone marrow transplantation. Recent experimental data in skin suggest that early lesion may precede morphologic evidence of direct infiltration by effector cells. The purpose of this study was to further elucidate the mechanism and kinetics of epithelial injury in acute GVHD produced in mouse strains (B10.BR/CBA) receiving bone marrow transplants across minor histocompatibility loci. Skin and tongue mucosa of hosts receiving CD8 T-cell-enriched, whole T-cell-enriched, or T-cell-depleted bone marrow transplants were sequentially harvested and studied histologically and by the terminal uridine deoxynucleotidyl transferase end ligation technique to detect apoptotic cells. Apoptosis involving putative stem cells is the predominant form of cellular injury in acute experimental GVHD. Although apoptosis correlated with the onset of lymphocyte infiltration relatively late in CD8-mediated disease, apoptosis was bimodal in whole T-cell-mediated disease, with an early peak that preceded histologic evidence of lymphocyte infiltration. These findings establish a central role for apoptosis in epithelial cell injury in acute GVHD and indicate that T-cell composition of the donor marrow inoculum may influence the pattern and kinetics of epithelial damage.

Cellular fibronectin is induced in ultraviolet-exposed human skin and induces IL-10 production by monocytes/macrophages.

CD11b+ monocytic/macrophagic cells that infiltrate human skin after in vivo ultraviolet exposure potently produce interleukin-10. We hypothesized that binding of monocyte beta1 integrins to ultraviolet-induced extracellular matrix ligands, such as fibronectin, after entry of blood monocytes into the dermis, is involved in the modulation of immunoregulatory monocytic cytokines. Immunostaining of human skin and reverse transcriptase-polymerase chain reaction studies revealed that the embryonic isoform of cellular fibronectin, in which the extra domain A (EDA) segment is spliced in (EDA+ cellular fibronectin), and confers enhanced binding to beta1 integrins, is newly induced and is associated with infiltrating CD11b+ cells post in vivo ultraviolet exposure. We then tested the effect of fibronectin on resting purified peripheral monocytes in vitro. We found that monocyte interleukin-10, but not interleukin-12, was significantly induced in a concentration-dependent manner by in vitro binding to cellular fibronectin (n = 6), but not plasma fibronectin. Tumor necrosis factor-alpha was also induced in a concentration-dependent manner, but to a lesser extent. Monoclonal antibodies to beta1 integrins beta-subunit (CD29) also strongly induced tumor necrosis factor-alpha and interleukin-10 production, but not interleukin-12. Neutralization of tumor necrosis factor-alpha reduced by 54% the interleukin-10 production that was induced by monocytes binding to cellular fibronectin, indicating that interleukin-10 induction is at least in part dependent upon concomitant autocrine tumor necrosis factor-alpha release. In conclusion, ultraviolet skin injury results in increased production and deposition of EDA+ cellular fibronectin in the papillary dermis, which may be one of the key signals capable of inducing interleukin-10 but not interleukin-12 in monocytes that infiltrate micromilieu of human skin after ultraviolet exposure.

In human skin, UVB initiates early induction of IL-10 over IL-12 preferentially in the expanding dermal monocytic/macrophagic population.

In contrast to Langerhans cells, which make interleukin (IL)-12, differentiated macrophages that infiltrate the epidermis 72 h after ultraviolet B (UV) irradiation potently produce IL-10 mRNA and secrete IL-10 protein. We asked whether differentiated UV macrophages in the epidermis acquired their activated, IL-10hi status as a result of entering the epidermis or as a result of encountering UV-induced changes in the dermal microenvironment. In this study, sequential section immunostaining directly showed dynamic and reciprocal changes of infiltrating CD11b+ macrophages and CD1a+ Langerhans cell loss in human epidermis and dermis after in vivo UV exposure in relation to the microanatomic localization of newly appearing dermal cells that stain for IL-10 mRNA by in situ hybridization. Using quantitative reverse transcriptase polymerase chain reaction on purified dermal cell subsets, the first significant rise in IL-10 mRNA occurred 6 h after UV in the dermal CD11b+ (CD1-, 3-, 24-, 56-) monocytic/macrophagic population. Significant induction of IL-10 mRNA 24 h post-UV was limited to the CD11b+ CD1- subset (p = 0.006). The fold increase of IL-10 mRNA relative to 0 h by the CD11b+ dermal monocytic/macrophagic population peaked at 24-48 h and tapered thereafter. Intense IL-10 production by macrophages in the epidermis appeared to follow dermal changes, with maximum production at 72 h, indicating migration/activation of this population from the dermis, and the remainder of dermal cells, depleted of monocyte/macrophages and Langerhans cell-like antigen-presenting cells, showed no increase in IL-10 at any time point post-UV. IL-10 protein-producing CD11b+ macrophages in the dermis were also documented by flow cytometry. IL-12 mRNA was differentially regulated from IL-10 after UV, in that IL-12 was consistently downregulated in the CD11b+ monocytic/macrophagic population (p < 0.0002). Taken together, monocytic/macrophagic cells with high IL-10 and low IL-12 expression initially appear in the dermis as early as 6 h, and then appear in the epidermis, implicating the dermis as the primary site of activation/signaling for IL-10 upregulation in cutaneous antigen-presenting cells.

Overexpression of the oncofetal Fn variant containing the EDA splice-in segment in the dermal-epidermal junction of psoriatic uninvolved skin.

The extracellular matrix protein, Fn, has critical functions in cell attachment, migration, differentiation, and proliferation. We have previously shown that fibronectin (Fn) is abnormally expressed and potentiates entry into the cell cycle of basal keratinocytes in uninvolved psoriatic skin, in combination with T cell lymphokines. It is not known what type of Fn is present in psoriatic skin, however, and how this Fn may regulate signaling. Embryonic forms of cellular Fn containing extra domains, designated EDA and EDB, are generated by alternative splicing and are seen in proliferating, developing tissue and in wound healing. Because the EDA segment enhances the integrin binding sequence Arg, Gly, Asp (RGD), which, when present, has been shown to be critical in integrin-extracellular matrix signaling, we were particularly interested in determining whether or not EDA-containing Fn (EDA+Fn) represented the aberrantly expressed Fn in psoriasis. Increased EDA+ Fn protein was demonstrated by immunostaining at the dermal-epidermal junction in clinically uninvolved skin from six of six patients with psoriasis, but not in skin from control subjects. Using reverse transcription polymerase chain reaction an increased ratio of EDA+ Fn versus EDA- Fn mRNA was present in epidermal samples from psoriatic but not control individuals. Interestingly, the EDA+Fn in the psoriatic epidermis had the IIICS region spliced out (EDA+, FDB-, IIICS-, III9+), which was shared with normal epidermis (EDA-, EDB-, IIICS-, III9+). These results suggest a selective predominance of the EDA+ Fn isoform at the dermal-epidermal junction of psoriatic skin. The consistent aberrant localization of EDA+ Fn at the dermal-epidermal junction in uninvolved skin of psoriatics may confer the hyperresponsiveness of psoriatic uninvolved basal keratinocytes for rapid cellular proliferation in response to T cell signals. Key words: immunohistochemistry/integrin/keratinocyte/RT-PCR.

The human hair follicle: a reservoir of CD40+ B7-deficient Langerhans cells that repopulate epidermis after UVB exposure.

The ability of skin to maintain its protective structural and functional integrity depends on both resident and circulating cells. Until now, it was thought that dendritic antigen presenting cells of epidermis (Langerhans cells) were replaced by circulating bone marrow derived precursors. Here we show by immunostaining studies of timed biopsies taken from human skin after ultraviolet exposure, that hair follicle is a critical reservoir of Langerhans cells that repopulate epidermis depleted of Langerhans cells by a single four minimal erythema dose of ultraviolet B. Immunostaining with antibodies to thymidine dimers showed that ultraviolet B only penetrated the superficial hair follicle opening, whereas deeper follicle was relatively protected. Langerhans cells migrating from hair follicle into epidermis 72 h after ultraviolet exposure have a partial deficiency of molecules important to T cell costimulation. We used four color flow cytometry to show that Langerhans cells isolated from epidermis 72 h after ultraviolet B can upregulate CD40 but not B7-1 or B7-2 expression in culture, suggesting a different phenotype of hair follicle Langerhans cells. Therefore, the hair follicle is a specialized immune compartment of the skin that serves as an intermediate reservoir of Langerhans cells between bone marrow and epidermis, and that may play a critical role in immune surveillance.