Bone-targeting engineered small extracellular vesicles carrying anti-miR-6359-CGGGAGC prevent valproic acid-induced bone loss

The clinical role and underlying mechanisms of valproic acid (VPA) on bone homeostasis remain controversial. Herein, we confirmed that VPA treatment was associated with decreased bone mass and bone mineral density (BMD) in both patients and mice. This effect was attributed to VPA-induced elevation in osteoclast formation and activity. Through RNA-sequencing, we observed a significant rise in precursor miR-6359 expression in VPA-treated osteoclast precursors in vitro, and further, a marked upregulation of mature miR-6359 (miR-6359) in vivo was demonstrated using quantitative real-time PCR (qRT-PCR) and miR-6359 fluorescent in situ hybridization (miR-6359-FISH). Specifically, the miR-6359 was predominantly increased in osteoclast precursors and macrophages but not in neutrophils, T lymphocytes, monocytes and bone marrow-derived mesenchymal stem cells (BMSCs) following VPA stimulation, which influenced osteoclast differentiation and bone-resorptive activity. Additionally, VPA-induced miR-6359 enrichment in osteoclast precursors enhanced reactive oxygen species (ROS) production by silencing the SIRT3 protein expression, followed by activation of the MAPK signaling pathway, which enhanced osteoclast formation and activity, thereby accelerating bone loss. Currently, there are no medications that can effectively treat VPA-induced bone loss. Therefore, we constructed engineered small extracellular vesicles (E-sEVs) targeting osteoclast precursors in bone and naturally carrying anti-miR-6359 by introducing of EXOmotif (CGGGAGC) in the 3'-end of the anti-miR-6359 sequence. We confirmed that the E-sEVs exhibited decent bone/osteoclast precursor targeting and exerted protective therapeutic effects on VPA-induced bone loss, but not on ovariectomy (OVX) and glucocorticoid-induced osteoporotic models, deepening our understanding of the underlying mechanism and treatment strategies for VPA-induced bone loss.

Modern Machiavelli? The illusion of ChatGPT-generated patient reviews in plastic and aesthetic surgery based on 9000 review classifications

BACKGROUND

Online patient reviews are crucial in guiding individuals who seek plastic surgery, but artificial chatbots pose a threat of disseminating fake reviews. This study aimed to compare real patient feedback with ChatGPT-generated reviews for the top five US plastic surgery procedures.

METHODS

Thirty real patient reviews on rhinoplasty, blepharoplasty, facelift, liposuction, and breast augmentation were collected from RealSelf and used as templates for ChatGPT to generate matching patient reviews. Prolific users (n = 30) assessed 150 pairs of reviews to identify human-written and artificial intelligence (AI)-generated reviews. Patient reviews were further assessed using AI content detector software (Copyleaks AI).

RESULTS

Among the 9000 classification tasks, 64.3% and 35.7% of reviews were classified as authentic and fake, respectively. On an average, the author (human versus machine) was correctly identified in 59.6% of cases, and this poor classification performance was consistent across all procedures. Patients with prior aesthetic treatment showed poorer classification performance than those without (p < 0.05). The mean character count in human-written reviews was significantly higher (p < 0.001) that that in AI-generated reviews, with a significant correlation between character count and participants' accuracy rate (p < 0.001). Emotional timbre of reviews differed significantly with "happiness" being more prevalent in human-written reviews (p < 0.001), and "disappointment" being more prevalent in AI reviews (p = 0.005). Copyleaks AI correctly classified 96.7% and 69.3% of human-written and ChatGPT-generated reviews, respectively.

CONCLUSION

ChatGPT convincingly replicates authentic patient reviews, even deceiving commercial AI detection software. Analyzing emotional tone and review length can help differentiate real from fake reviews, underscoring the need to educate both patients and physicians to prevent misinformation and mistrust.

Moderate LMWH Anticoagulation Improves Success Rate of Hind Limb Allotransplantation in Mice

Background

The mouse hind limb model represents a powerful research tool in vascularized composite tissue allotransplantation, but its applicability is limited due to poor graft survival (62%-83%). Vascular thrombosis and massive hemorrhage are the major causes for these drop-outs. We hypothesize that because of better anticoagulation effect and lower risk of thrombocytopenia, application of low molecular weight heparin (LMWH) will minimize vascular complications and enhance graft and animal survival.

Methods

Fifty allogeneic hind limb transplantations were performed (C57BL/6 to DBA/2 mice) using five different anticoagulation protocols. Bleeding and thromboembolic events were recorded macroscopically by postoperative hemorrhage and livid discoloration of the graft, respectively. Graft perfusion and survival were monitored daily by capillary-refill-time of graft toes within 2-3 seconds. Vascular congestion and tissue necrosis were examined by histological evaluation of hematoxylin-eosin-stained tissue sections.

Results

All transplantations were technically successful. Increase in thromboembolic events and a concomitant decrease in bleeding events were observed with the decreasing concentration of heparin in the perfusion solution. Although treatment of donor and recipient with low dose of LMWH could not reduce thromboembolic events, moderate dose effectively reduced these events. Compared with the poor outcome of graft perfusion with heparin alone, additional treatment of donor and recipient with low dose of LMWH improved graft and animal survival by 18%. Interestingly, animals treated with moderate dose of LMWH demonstrated 100% graft and animal survival.

Conclusions

Treatment of donor and recipient mice with a moderate dose of LMWH prevents vascular complications and improves the outcome of murine hind limb transplants.

Cellular activation pathways and interaction networks in vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) is an evolving field of reconstructive surgery that has revolutionized the treatment of patients with devastating injuries, including those with limb losses or facial disfigurement. The transplanted units are typically comprised of different tissue types, including skin, mucosa, blood and lymphatic vasculature, muscle, and bone. It is widely accepted that the antigenicity of some VCA components, such as skin, is particularly potent in eliciting a strong recipient rejection response following transplantation. The fine line between tolerance and rejection of the graft is orchestrated by different cell types, including both donor and recipient-derived lymphocytes, macrophages, and other immune and donor-derived tissue cells (e.g., endothelium). Here, we delineate the role of different cell and tissue types during VCA rejection. Rejection of VCA grafts and the necessity of life-long multidrug immunosuppression remains one of the major challenges in this field. This review sheds light on recent developments in decoding the cellular signature of graft rejection in VCA and how these may, ultimately, influence the clinical management of VCA patients by way of novel therapies that target specific cellular processes.

Measurement of serum intact parathyroid hormone (iPTH) at the end of total thyroidectomy: A reliable parameter for hypocalcemia?

Objective

Total thyroidectomy represents the gold standard surgical procedure for patients with malignant thyroid disease. Over the past decades, the total thyroidectomy gradually replaced the subtotal thyroidectomy for benign thyroid disorders as well. Postoperative hypocalcemia remains the most frequent complication. The close proximity of parathyroid glands to the thyroid capsule leads often to devascularization or adventitious removal of parathyroid tissue. Clinical symptoms like paresthesia, tingling, muscle cramps or seizures often occur. Combined measurement of intact parathyroid hormone (iPTH) and calcium after the operation are used worldwide to predict postoperative hypoparathyroidism. The purpose of this study was to find out the incidence of decreased iPTH at the end of surgery and its reliability in predicting hypocalcemia.

Methods

We performed a retrospective analysis of 534 patients who underwent total thyroidectomy at our institution between 2000 and 2019. Medical records were reviewed to analyze the patient characteristics, indication of the procedure, laboratory and histological results, postoperative management and complications. The iPTH was measured before and at the end of the surgery, while the calcium was measured at the first postoperative day. The iPTH assay at our hospital has a normal range between 15.0 and 80.0 pg/ml. Meanwhile hypocalcemia was defined as a calcium measurement &lt; 2.2 mmol/l.

Results

The mean age of the patients was 55.34 years. The female to male ratio was 4.6:1. The mean preoperative iPTH of our cohort was 48.35 pg/ml, while the postoperative iPTH was 31.74 pg/ml, indicating a mean reduction of 35.75%. A total of 174 patients (32.6%) had a iPTH &lt; 15.0 pg/ml at the end of the surgery, indicating a reduction of 75.6%. 22 of these 174 patients (12.6%) developed clinical symptoms of hypocalcemia. In contrast only 3 patients (0.08%) with normal iPTH developed symptoms. Whole parathyroid glands were identified in 95/534 (17.8%), whereas from the 174 patients with iPTH &lt; 15.0 pg/ml, 56 (32.2%) had at least one parathyroid gland in the operative specimens.

Conclusion

Measurement of iPTH at the end of total thyroidectomy is a good predictor to detect patient who are at risk for developing symptomatic hypocalcemia and calcium substitution can be started at the same day. A normal iPTH almost excludes symptomatic hypocalcemia.

[EUROCRINE®: adrenal surgery 2015-2019- surprising initial results]

Hintergrund

Seit 2015 erfolgt in Europa mithilfe des EUROCRINE®-Registers eine systematische Dokumentation endokrin-chirurgischer Operationen. Ziel dieser ersten Auswertung war eine Darstellung der Versorgungsrealität für Nebenniereneingriffe in einem homogenen Versorgungsumfeld, entsprechend des deutschsprachigen Raums – bzw. des Präsenzgebiets der Chirurgischen Arbeitsgemeinschaft Endokrinologie (CAEK) der Deutschen Gesellschaft für Allgemein- und Viszeralchirurgie (DGAV) – einschließlich einer Analyse der Adhärenz zu geltenden Therapieempfehlungen.

Methodik

Es erfolgte eine deskriptive Analyse der präoperativen Diagnostik, der angewandten Operationstechniken sowie der zugrunde liegenden histologischen Entitäten der zwischen den Jahren 2015 und 2019 über EUROCRINE® in Deutschland, Österreich und der Schweiz dokumentierten Nebennierenoperationen.

Ergebnisse

In den insgesamt 21 teilnehmenden Kliniken des deutschsprachigen EUROCRINE®-Gebiets wurden 658 Operationen an Nebennieren durchgeführt. In 90 % erfolgten unilaterale, in 3 % bilaterale Adrenalektomien und in 7 % andere Resektionsverfahren. Die in 41 % der Operationen dokumentierte histologische Hauptdiagnose war das adrenokortikale Adenom. In 15 % lagen maligne Befunde zugrunde (einschließlich 6 % Nebennierenrindenkarzinome (ACC) und 8 % Nebennierenmetastasen). 23 % der Operationen erfolgten bei Phäochromozytomen. Diese wurden zu 82 % minimal-invasiv operiert, Nebennierenrindenkarzinome lediglich zu 28 % und Nebennierenmetastasen zu 66 %.

Schlussfolgerung

Überraschenderweise wurden nach Nebennierenadenomen und Phäochromozytomen an dritthäufigster Stelle Nebennierenmetastasen unterschiedlicher Primärtumoren reseziert. 28 % der ACC waren für minimal-invasive Techniken vorgesehen, wobei 20 % dieser Fälle eine Konversion zur offenen Operation erforderten. Die aktuelle Analyse deckte Diskrepanzen zwischen Versorgungsrealität und Leitlinienempfehlungen auf, aus denen sich zahlreiche Fragestellungen ergeben, welche nun in ein überarbeitetes EUROCRINE®-Modul zur Dokumentation von Nebennierenoperationen einfließen werden.

Development of a web tool to increase research literacy in underserved populations through public library partnerships

OBJECTIVE

Inadequate diversity in clinical trials is widely recognized as a significant contributing factor to health disparities experienced by racial/ethnic minorities and other diverse populations in the US. To address this in a scalable way, we sought to develop a web tool that could help enhance underserved minority participation in clinical research.

METHODS

We used our research literacy support flashcard tool as the initial prototype for human-centered design and usability testing of the web tool Health for All in public library settings. After forming partnerships with leadership from Chicago Public Libraries (CPL), local medical libraries, and the Chicago Department of Public Health, we conducted seven iterative design sessions with focus groups of library patrons and library staff from six CPL branches serving underserved communities followed by two rounds of usability testing and website modification.

RESULTS

Based on the qualitative research findings from Design Sessions 1-7, we enacted the design decision of a website that was a hybrid of fact-filled and vignette (personal stories) paper prototypes divided into 4 modules (trust, diversity, healthy volunteers, pros/cons), each with their own outcome metrics. The website was thus constructed, and navigation issues identified in two rounds of usability testing by library patrons were addressed through further website modification, followed by the launch of a beta version of a hybridized single-scrolling and guided module prototype to allow further development with website analytics.

CONCLUSIONS

We report the development of Health for All, a website designed to enhance racial/ethnic minority participation in clinical trials by imparting research literacy, mitigating distrust engendered by longstanding racism and discrimination, and providing connections to clinical trials recruiting participants.

Is authorship sufficient for today's collaborative research? A call for contributor roles

Assigning authorship and recognizing contributions to scholarly works is challenging on many levels. Here we discuss ethical, social, and technical challenges to the concept of authorship that may impede the recognition of contributions to a scholarly work. Recent work in the field of authorship shows that shifting to a more inclusive contributorship approach may address these challenges. Recent efforts to enable better recognition of contributions to scholarship include the development of the Contributor Role Ontology (CRO), which extends the CRediT taxonomy and can be used in information systems for structuring contributions. We also introduce the Contributor Attribution Model (CAM), which provides a simple data model that relates the contributor to research objects via the role that they played, as well as the provenance of the information. Finally, requirements for the adoption of a contributorship-based approach are discussed.

Outcomes of liver transplantation for non-alcoholic steatohepatitis: A European Liver Transplant Registry study

BACKGROUND & AIMS

Little is known about outcomes of liver transplantation for patients with non-alcoholic steatohepatitis (NASH). We aimed to determine the frequency and outcomes of liver transplantation for patients with NASH in Europe and identify prognostic factors.

METHODS

We analysed data from patients transplanted for end-stage liver disease between January 2002 and December 2016 using the European Liver Transplant Registry database. We compared data between patients with NASH versus other aetiologies. The principle endpoints were patient and overall allograft survival.

RESULTS

Among 68,950 adults undergoing first liver transplantation, 4.0% were transplanted for NASH - an increase from 1.2% in 2002 to 8.4% in 2016. A greater proportion of patients transplanted for NASH (39.1%) had hepatocellular carcinoma (HCC) than non-NASH patients (28.9%, p <0.001). NASH was not significantly associated with survival of patients (hazard ratio [HR] 1.02, p = 0.713) or grafts (HR 0.99; p = 0.815) after accounting for available recipient and donor variables. Infection (24.0%) and cardio/cerebrovascular complications (5.3%) were the commonest causes of death in patients with NASH without HCC. Increasing recipient age (61-65 years: HR 2.07, p <0.001; >65: HR 1.72, p = 0.017), elevated model for end-stage liver disease score (>23: HR 1.48, p = 0.048) and low (<18.5 kg/m²: HR 4.29, p = 0.048) or high (>40 kg/m²: HR 1.96, p = 0.012) recipient body mass index independently predicted death in patients transplanted for NASH without HCC. Data must be interpreted in the context of absent recognised confounders, such as pre-morbid metabolic risk factors.

CONCLUSIONS

The number and proportion of liver transplants performed for NASH in Europe has increased from 2002 through 2016. HCC was more common in patients transplanted with NASH. Survival of patients and grafts in patients with NASH is comparable to that of other disease indications.

LAY SUMMARY

The prevalence of non-alcoholic fatty liver disease has increased dramatically in parallel with the worldwide increase in obesity and diabetes. Its progressive form, non-alcoholic steatohepatitis, is a growing indication for liver transplantation in Europe, with good overall outcomes reported. However, careful risk factor assessment is required to maintain favourable post-transplant outcomes in patients with non-alcoholic steatohepatitis.

Identification of serological markers for pre- and postoperative fasting periods

BACKGROUND & AIMS

Prolonged preoperative fasting periods lead to catabolic states and decelerate recovery after surgery. Valid plasma markers reflecting the patients' metabolic state may improve tailored nutrition support before surgery. Within this study, we sought to advance the knowledge on fasting time-sensitive plasma markers that allow the metabolic characterisation of surgical patients for an optimised preoperative metabolic preparation.

METHODS

Patients scheduled for elective surgery of the upper (n = 23) or lower (n = 27) gastrointestinal tract participated in a prospective observational study. Patients' charateristics and nutritional status were recorded and blood samples were drawn on the day of admission. Further blood samples were collected before skin incision of the surgical procedure, on postoperative day 3 and on the day of discharge. Values of clinical chemistry, electrolytes, hemograms and plasma amino acids were determined and correlated with fasting times.

RESULTS

Preoperative fasting times were positively correlated with plasma levels of valine, leucine, serine, α-amino butyric acid, free fatty acids, 3-hydroxy butyric acid and significantly negative correlated with chloride and glutamic acid. Postoperative fasting times were correlated with erythrocytes, leukocytes and plasma levels of albumin, CRP, HDL, asparagine and 3-methylhistidine. The multivariate regression analysis revealed glutamic acid and valine as significant independent predictors of preoperative fasting periods. The regression model showed best performance (sensitivity of 90.91% and specificity of 92.31%) to detect patients fasted for ≥20 h.

CONCLUSION

Valine and glutamic acid appear as independent metabolic markers for accurate prediction of prolonged fasting periods, independent of the overall nutritional status, age or BMI of patients.

High incidence of hepatocellular carcinoma and postoperative complications in patients with nonalcoholic steatohepatitis as a primary indication for deceased liver transplantation

BACKGROUND AND AIMS

Nonalcoholic steatohepatitis (NASH) is an increasingly prevalent indication for liver transplantation (LT) across the world. The relative outcomes following transplantation are poorly described in this cohort. We aimed to analyze the incidence and outcome of LT for NASH as compared with other indications.

PATIENTS AND METHODS

This is a retrospective analysis of 513 patients who underwent deceased-donor, adult LT between 2002 and 2012 as recorded at the Medical University of Innsbruck, Austria.

RESULTS

The prevalence of NASH cirrhosis as indication for liver transplantation was 12.7% (65/513). Patient survival in patients with NASH was comparable to other indications, including alcohol-induced liver steatosis (ALD) and hepatitis C virus (HCV) (P=0.208). Patients with NASH were older, had a higher model of end-stage liver disease score and a higher BMI, but patient survival and graft survival were equivalent to other indications. Patients with hepatocellular carcinoma (HCC) as primary indication for liver transplantation showed significantly inferior overall survival as compared with the other indications (P=0.003). Patients with NASH had coexisting HCC in 53.7% of cases, whereas HCC in ALD, HCV and other indications was prevalent in 31.2, 47.7, and 34.5%, respectively (P<0.0001). Patients with NASH had a higher incidence of advanced HCCs (outside the Milan criteria) than patients with ALD, HCV, and other indications (P=0.034). Postoperative complications were significantly higher in the NASH cohort (P=0.048).

CONCLUSION

In this single-center LT database analysis, patients with NASH have a higher incidence and a more rapid progression of HCC as well as an increased incidence of postoperative complications. Our findings warrant confirmation by others.

Epigenetic enzymes influenced by oxidative stress and hypoxia mimetic in osteoblasts are differentially expressed in patients with osteoporosis and osteoarthritis

Epigenetic mechanisms including posttranslational histone modifications and DNA methylation are emerging as important determinants of bone homeostasis. With our case-control study we aimed to identify which chromatin-modifying enzymes could be involved in the pathology of postmenopausal osteoporosis and osteoarthritis while co-regulated by estrogens, oxidative stress and hypoxia. Gene expression of HAT1, KAT5, HDAC6, MBD1 and DNMT3A affected by oxidative stress and hypoxia in an in vitro qPCR screening step performed on an osteoblast cell line was analysed in trabecular bone tissue samples from 96 patients. Their expression was significantly reduced in patients with postmenopausal osteoporosis and osteoarthritis as compared to autopsy controls and significantly correlated with bone mineral density and several bone histomorphometry-derived parameters of bone quality and quantity as well as indicators of oxidative stress, RANK/RANKL/OPG system and angiogenesis. Furthermore, oxidative stress increased DNA methylation levels at the RANKL and OPG promoters while decreasing histone acetylation levels at these two genes. Our study is the first to show that higher expression of HAT1, HDAC6 and MBD1 is associated with superior quantity as well as quality of the bone tissue having a more favourable trabecular structure.

Managing Contributions to the Unified Astronomy Thesaurus

The Unified Astronomy Thesaurus (UAT) project managers have long defined the UAT as "an open, interoperable, and community-supported thesaurus." How do we solicit the detailed, comprehensive, and consistent community feedback that is required to keep the UAT relevant? The Steering Committee for the UAT has developed a visual organizational tool that lets reviewers suggest new concepts and restructure the existing hierarchy. Researchers and librarians can use this "Sorting Tool" to submit contributions and feedback to the UAT. The UAT Curator adds feedback to the UAT’s GitHub Issues, which allows for tracking, searching, and referencing the suggestions. The UAT Curator implements the accepted suggestions, preparing to include them in a future release of the Unified Astronomy The saurus. This process of continual improvement ensures that the UAT project remains community supported.

A day in the life of third-year medical students: using an ethnographic method to understand information seeking and use

Objective

The authors undertook this project to learn how third-year medical students seek and use information in the course of daily activities, especially activities conducted in clinical settings in a variety of institutions.

Methods

We recruited sixty-eight third-year undergraduate medical school students to create a mapping diary of a day that included clinical activities. We conducted semi-structured interviews based on the mapping diaries. Using content and thematic analyses of the resulting interview transcripts, we developed an ethnographic case study for each participant.

Results

In the studied sample, we identified a broad range of information resources used for personal, clinical, and educational use. Participants relied heavily on technology throughout their day, including desktop computers, smart phones, handheld tablets, and laptops. Time management was a pervasive theme in the interviews, with participants squeezing in time to study for exams wherever and whenever they could. Selection of a particular information resource or technology to use was governed largely by the convenience of using that resource or technology. When obstacles were encountered, workarounds might be sought, but in many cases, the resource or technology would be abandoned in favor of a more convenient solution. Convenience was also a consideration in choosing spaces to use for clinical duties or for study, with specific considerations of available technology, proximity to clinical areas, and security for belongings contributing to choices made.

Conclusions

Some of our results align with those of other recent studies of information use among medical students, residents, and practicing physicians. In particular, the fast-paced clinical setting favors use of information resources that are fast and easy to use. We demonstrated that the methods used are suitable to better understand clinicians’ discovery and use of information.

A Novel Rodent Orthotopic Forelimb Transplantation Model That Allows for Reliable Assessment of Functional Recovery Resulting From Nerve Regeneration

Improved nerve regeneration and functional outcomes would greatly enhance the utility of vascularized composite allotransplantation (VCA) such as hand and upper extremity transplantation. However, research aimed at achieving this goal has been limited by the lack of a functional VCA animal model. We have developed a novel rat midhumeral forelimb transplant model that allows for the characterization of upper extremity functional recovery following transplantation. At the final end point of 12 weeks, we found that animals with forelimb transplantation including median, ulnar and radial nerve coaptation demonstrated significantly improved grip strength and forelimb function as compared to forelimb transplantation without nerve approximation (grip strength: 1.71N ± 0.57 vs. no appreciable recovery; IBB scale: 2.6 ± 0.7? vs. 0.8 ± 0.40; p = 0.0005), and similar recovery to nerve transection-and-repair only (grip strength: 1.71N ± 0.57 vs. 2.03 ± 0.42.6; IBB scale: 2.6 ± 0.7 vs. 2.8 ± 0.8; p = ns). Moreover, all forelimb transplant animals with nerve coaptation displayed robust axonal regeneration with myelination and reduced flexor muscle atrophy when compared to forelimb transplant animals without nerve coaptation. In conclusion, this is the first VCA small-animal model that allows for reliable and reproducible measurement of behavioral functional recovery in addition to histologic evaluation of nerve regeneration and graft reinnervation.

The difficulty in defining extended donor criteria for liver grafts: the Eurotransplant experience

Donor criteria for liver grafts have been expanded because of organ shortage. Currently, no exact definitions for extended donor grafts have been established. The aim of this study was to analyze the impact of donor-specific risk factors, independent of recipient characteristics. In collaboration with Eurotransplant and European Liver Transplant Register, solely donor-specific parameters were correlated with 1-year survival following liver transplantation. Analyses of 4701 donors between 2000 and 2005 resulted in the development of a nomogram to estimate graft survival for available grafts. Predictions by nomogram were compared to those by Donor Risk Index (DRI). In the multivariate analysis, cold ischemic time (CIT), highest sodium, cause of donor death, γ-glutamyl transferase (γ-GT), and donor sex (female) were statistically significant factors for 3 months; CIT, γ-GT, and cause of donor death for 12-month survival. The median DRI of this study population was 1.45 (Q1: 1.17; Q3: 1.67). The agreement between the nomogram and DRI was weak (kappa = 0.23). Several donor-specific risk factors were identified for early survival after liver transplantation. The provided nomogram will support quick organ quality assessment. Nevertheless, this study showed the difficulties of determining an exact definition of extended criteria donors.

Organ donation

Liver transplantation expertise has expanded throughout the world to the point where liver transplants are available in most developed countries. In many cases, however, legislation and regulations have not kept pace with the advances in healthcare technology. In a few cases, these regulatory voids have lead to exploitation and profit making around transplantation activities. The growing patient demand has motivated governments to develop numerous national efforts to improve the standards by which organ donation and transplantation are practiced and programs to increase the number organ of donors, most notably in Spain. Although these efforts have helped, the worldwide demand for lifesaving transplantation exerts extreme pressures such that financial incentives, profit making, and overt exploitation have compelled the World Health Organization to issue guiding principles. Other efforts to increase the number of available organs have centered on expanding the medical criteria for acceptable organ donors and using donation after cardiac death protocols. Implicit in these efforts is the need to understand, both on the part of the practitioner and the recipient, the higher risks involved in using these donors, the circumstances in which taking such risks are justified, and that all parties-including those responsible for paying the higher healthcare costs associated with using these organs-are willing to assume these risks. Also important is recognizing that the risks of transmission of donor disease to recipients are very low but not zero, even though these events receive enormous media attention. As the demand for organs rises relentlessly, more research must be devoted to understanding how to make the marginal donor organs function better.

Long-term results after stapled hemorrhoidopexy: high patient satisfaction despite frequent postoperative symptoms

PURPOSE

Stapled hemorrhoidopexy has been demonstrated to be advantageous in the short term compared with the traditional techniques. We aimed to evaluate long-term results after stapled hemorrhoidopexy and to assess patient satisfaction in association with postoperative hemorrhoidal symptoms.

METHODS

This prospective study included 216 patients with Grade 2 or 3 hemorrhoids, who had stapled hemorrhoidopexy using the circular stapled technique. The results were evaluated by a standardized questionnaire at least 12 months after the operation. The primary end point was patient satisfaction; secondary end points included specific hemorrhoidal symptoms.

RESULTS

Followup data were obtained for 193 of 216 patients (89 percent) with a median follow-up of 28 (range, 12-53) months, most of whom (89 percent) were satisfied or very satisfied with the surgery. The main preoperative symptom was no longer present postoperatively in 66 percent of patients, was relieved in 28 percent, and had worsened in 2 percent. Postoperative complaints included symptoms of hemorrhoidal prolapse (24 percent of patients), anal bleeding (20 percent), anal pain (25 percent) fecal soiling/leakage (31 percent), fecal urgency (40 percent), and local discomfort (38 percent). Bivariate analysis showed significant associations between each of these symptoms and patient satisfaction. Nine patients (5 percent) were reoperated on during the follow-up period.

CONCLUSIONS

Long-term patient satisfaction was high in most of patients after stapled hemorrhoidopexy for second-degree and third-degree hemorrhoids. However, an unsatisfactory outcome was significantly related to postoperative hemorrhoidal symptoms such as prolapse, fecal soiling/leakage, and new onset of fecal urgency.

Diagnostic procedures after completion of oral immunisation against classical swine fever in wild boar

The purpose of this paper is to define diagnostic procedures for wild boar after the completion of oral immunisation against classical swine fever (CSF). Epidemiological analysis of CSF in wild boar in Germany demonstrated that it is vital to carry out virological investigations on all animals found dead, sick or involved in traffic accidents. In principle, this should ensure an effective and prompt diagnosis of CSF. In addition, a defined number of wild boar, especially young animals < or = 6 months old, should also be tested for CSF virus to guarantee a high confidence level in the virological monitoring. Which animals should be examined serologically depends on the age class investigated, the season in which vaccination was stopped and the period of time since completion of vaccination. Therefore, different serological procedures have been defined for different situations during the first three years after completion of oral immunisation.

Outcome and quality of life after open surgery versus endoscopic stapler-assisted esophagodiverticulostomy for Zenker's diverticulum

Two techniques for treatment of Zenker's diverticulum, endoscopic stapler-assisted esophagodiverticulostomy and open cricopharyngeal myotomy by transcervical approach, were compared with regard to patient satisfaction and quality of life. Between January 1994 and December 2004 a total of 47 patients with Zenker's diverticulum underwent surgery in our department. Besides the usual retrospective evaluation of details of surgery, all patients were sent a questionnaire on their actual complaints and quality of life according to the Gastrointestinal Quality of Life Index (GIQLI). Twenty patients had the endoscopic procedure (Group A), and 27 the open procedure (Group B). The preoperative symptoms were dysphagia in 96%, regurgitation of undigested food in 60%, cough in 19%, and pneumonia caused by recurrent aspiration in 9%. The length of surgery was on average 32 min (range 5-70 min) in Group A and 106 min (range 45-165 min) in Group B, and the length of hospital stay was 5.5 days (range 1-10 days) and 12.3 days (range 7-25 days), respectively. The results of the questionnaire showed that the preoperative symptoms had disappeared in up to 83%, and 91% in Group A and 100% in Group B would be willing to undergo surgery again. The mean GIQLI was 123 points in Group A and 118 points in Group B (healthy volunteers in the literature, 125 points). Both techniques showed good results in a long-term follow-up with regard to relief of symptoms and patient satisfaction. Both groups had an excellent Gastrointestinal Quality of Life Index, comparable to that of a healthy standard population.

Reduction in Slippage with 11-cm Lap-Band® and Change of Gastric Banding Technique

BACKGROUND

Slippage occurs after 2-18% of gastric bandings performed by the perigastric technique (PGT). We investigated the slippage-rate before and after the introduction of the pars flaccida technique (PFT) and the 11-cm Lap-Band, and the long-term results of the re-operated patients.

METHODS

Between Dec 1996 and Feb 2004, 360 patients with a mean BMI of 44 kg/m2 were operated. The PGT (n=168) and PFT9.75 (n=15) groups received the 9.75-cm Lap-Band, and the PFT11 group (n=177) received the new 11-cm Lap-Band. Follow-up rate was 99%.

RESULTS

Slippage occurred in a total of 31 patients from all groups (PGT, n=28, or 17%; PFT9.75, n=1, or 7%; PFT11, n=2, or 1%). Average yearly re-operation rate for slippage in the first 3 years postoperatively was 3.8%, 2.2% and 0.9%, respectively. Laparoscopic re-banding was necessary for posterior (n=19) or lateral (n=12) slippage. The late postoperative course after re-banding was: uneventful 58%, weight regain 35% and/or esophageal motility disorder 23%, secondary band intolerance 20%, and one persistent posterior slippage. 8 patients (26%) needed biliopancreatic diversion.

CONCLUSION

Since the introduction of the PFT and the 11-cm Lap-Band, we observed a significant reduction in slippage rate and no posterior slippage. Re-banding had a less favorable long-term result than did first-procedure banding.

[Twelve years of laparoscopic cholecystectomy]

We studied developments in indication, operation time, conversion rate, morbidity, and mortality from the beginning of laparoscopic cholecystectomy. Between 1990 and 2002 we prospectively evaluated 4498 patients undergoing cholecystectomy (CE), of whom 79% were treated laparoscopically (lap). In 6.6%, the procedure had to be converted from laparoscopic to open cholecystectomy (con), and 14% were performed open from the beginning (open). During the above time period, the rate of open CE decreased steadily (49% in 1990 to 7.2% in 2002). The average operation time of lap CE remained constant with an average of 74 min (range 20-330). The conversion rate decreased in spite of broader indication for lap CE in even more complicated gallstone diseases, from an initial 9.4% to 2.5%. Among intraoperative complications in lap and con, bile duct lesions remained constant with 5/3856 (0.1%), bleeding which led to conversion decreased from 1.9% to 0.3%, and the rate of gall bladder perforation increased from 12% to 20.5%. Thirty-day morbidity was 2% in lap CE, 5% in con, and 11.5% in open. The mortality was 0% in lap, 0.7% in con, and 1% in open.

CONCLUSION

Since the introduction of laparoscopic cholecystectomy the indication for this minimal-invasive operation steadily increased, the conversion-rate decreased and the complication-rate could be held low. Even with fast laparoscopic experience 7% of all cholecystectomies are technically difficult and remain to be carried out primarily in an open technique. The laparoscopic cholecystectomy has become the gold standard in the therapy of gallstone disease.

Optical pulsations from the anomalous X-ray pulsar 4U0142+61

Anomalous X-ray pulsars (AXPs) differ from ordinary radio pulsars in that their X-ray luminosity is orders of magnitude greater than their rate of rotational energy loss, and so they require an additional energy source. One possibility is that AXPs are highly magnetized neuron stars or 'magnetars' having surface magnetic fields greater than 10(14) G. This would make them similar to the soft gamma-ray repeaters (SGRs), but alternative models that do not require extreme magnetic fields also exist. An optical counterpart to the AXP 4U0142+61 was recently discovered, consistent with emission from a magnetar, but also from a magnetized hot white dwarf, or an accreting isolated neutron star. Here we report the detection of optical pulsations from 4U0142+61. The pulsed fraction of optical light (27 per cent) is five to ten times greater than that of soft X-rays, from which we conclude that 4U0142+61 is a magnetar. Although this establishes a direct relationship between AXPs and the soft gamma-ray repeaters, the evolutionary connection between AXPs, SGRs and radio pulsars remains controversial.

Oral immunisation of wild boar against classical swine fever: concluding analysis of the recent field trials in Germany

The recent oral immunisation trials in wild boar against classical swine fever (CSF) in Germany are described and evaluated in summary. After the first field study in Lower Saxony from 1993-1995 further immunisation trials started in Mecklenburg-Western Pomerania, Brandenburg, Lower Saxony, Baden-Württemberg and Saxony-Anhalt. The immunisation strategies and the size of the vaccination zones were different in the individual federal states. In principle, the bait vaccine based on the CSF virus strain "C" were laid out by hand. Later also the aerial distribution was carried out in selected areas of Mecklenburg-Western Pomerania. The application of baits by plane was introduced at the beginning of the immunisation measures in Saxony-Anhalt apart from the manual distribution. Up to now, the field trials show that the oral immunisation can be an additional tool for CSF control by increasing of herd immunity and reduction of the CSFV prevalence. However, the immunisation was not sufficient enough for young boars in the most field studies. Based on the evaluation of the immunisation experiments an improved immunisation procedure is recommended.

Cbfa1 does not regulate RANKL gene activity in stromal/osteoblastic cells

The rates of osteoblast and osteoclast formation are tightly balanced, possibly due to the requirement of mesenchymal osteoblast progenitors for osteoclastogenesis. Osteoblast differentiation requires the transcription factor Cbfa1, whereas osteoclastogenesis results from the interaction between receptor activator of NF kappa B ligand (RANKL), expressed on stromal/osteoblastic cells, and RANK, a surface receptor on hematopoietic precursors. A striking decrease in the number of osteoclasts in Cbfa1-deficient mice suggested that Cbfa1 might be involved in RANKL expression. To investigate this possibility and to elucidate the mechanisms regulating RANKL expression, we isolated the 5'-flanking region of the murine RANKL gene and found that it contains two potential binding sites for Cbfa1 (OSE2-like sites). Cbfa1 bound to either of these sites in gel shift assays and stimulated the activity of a chimeric promoter consisting of multimerized RANKL OSE2-like sites inserted upstream from a minimal thymidine kinase (tk) promoter in transient transfections. However, Cbfa1 cotransfection did not stimulate murine RANKL promoter-luciferase constructs. Further analysis revealed that removal of these sites from the RANKL promoter by either site-directed mutagenesis or 5'-deletion did not alter the basal activity of promoter-reporter constructs. Conditional expression of Cbfa1 in a stromal/osteoblastic cell line stimulated osteocalcin mRNA by fivefold, but had no significant effect on RANKL mRNA levels. Conversely, conditional expression of a dominant-negative form of Cbfa1 in the same cell line inhibited osteocalcin mRNA by threefold, but had no effect on RANKL mRNA. Although these results cannot rule out a novel function for Cbfa1 in RANKL expression, they demonstrate that Cbfa1 does not regulate RANKL gene activity in the same manner as known targets of this transcription factor, such as osteocalcin.

A new surgical concept for rectal replacement after low anterior resection: the transverse coloplasty pouch

OBJECTIVE

To analyze the feasibility, safety, complication and death rates, and early functional results of the transverse coloplasty pouch procedure after low anterior rectal resection and total mesorectal excision.

SUMMARY BACKGROUND DATA

The authors previously developed a novel neorectal reservoir, the transverse coloplasty pouch, in an animal model; they report the first clinical data of a prospective phase 1 study.

METHODS

Forty-one patients underwent low anterior rectal resection with total mesorectal excision for rectal cancer (n = 37) or benign pathology (n = 4). The continuity was restored with a transverse coloplasty pouch anastomosis, and the colon was defunctionalized for 3 months. Patients were followed up at 2-month intervals for functional outcome.

RESULTS

Intraoperative complications occurred in three patients (7%), none related to the transverse coloplasty pouch. There were no hospital deaths and the total complication rate was 27% (11/41); an anastomotic leakage rate of 7% was recorded. The stool frequency was 3.4 per 24 hours at 2 months follow-up and gradually decreased to 2.1 per 24 hours at 8 months. Stool dysfunctions such as stool urgency, fragmentation, and incontinence grade 1 and 2 were regularly observed until 6 months; the incidence significantly decreased thereafter. None of the patients had difficulties in pouch evacuation.

CONCLUSIONS

The transverse coloplasty pouch is a small-volume reservoir that can safely be used for reconstruction after sphincter-preserving rectal resection. The early functional outcome is favorable and can be compared to other colonic reservoirs. The concept of reducing early dysfunction seen after straight coloanal anastomosis and avoiding long-term problems of pouch evacuation is supported by this study. Future trials will compare the transverse coloplasty pouch with other techniques of restorative resections of the rectum.

Cbfa1 contributes to the osteoblast-specific expression of type I collagen genes

Type I collagen is composed of two chains, alpha1(I) and alpha2(I), encoded by two distinct genes, the alpha1(I) and alpha2(I) collagen genes, that are highly expressed in osteoblasts. In most physiological situations, alpha1(I) and alpha2(I) collagen expression is coregulated, suggesting that identical transcription factors control their expression. Here, we studied the role of Cbfa1, an osteoblast-specific transcription factor, in the control of alpha1(I) and alpha2(I) collagen expression in osteoblasts. A consensus Cbfa1-binding site, termed OSE2, is present at the same location in the alpha1(I) collagen promoter at approximately -1347 base pairs (bp) of the rat, mouse, and human genes. Cbfa1 can bind to this site, as demonstrated by electrophoretic mobility shift assay (EMSA) and supershift experiments using an anti-Cbfa1 antibody. Mutagenesis of the alpha1(I) collagen OSE2 at -1347 bp reduced the activity of a alpha1(I) collagen promoter fragment 2- to 3-fold. Moreover, multimers of this OSE2 at -1347bp confer osteoblast-specific activity to a minimum alpha1(I) collagen promoter fragment in DNA transfection experiments as well as in transgenic mice. An additional Cbfa1-binding element is present in the alpha1(I) collagen promoter of mouse, rat, and human at approximately position -372. This site binds Cbfa1 only weakly and does not act as a cis-acting activator of transcription when tested in DNA transfection experiments. Similar to alpha1(I) collagen, the mouse alpha2(I) collagen gene contains multiple OSE2 sites, of which one is conserved across multiple species. In EMSA, Cbfa1 binds to this site and multimers of this alpha2(I) OSE2 element confer osteoblast-specific activity to the minimum alpha1(I) collagen promoter in DNA transfection experiments. Thus, our results suggest that Cbfa1 is one of the positive regulators of the osteoblast-specific expression of both type I collagen genes.

Veno-occlusive disease, nodular regenerative hyperplasia and hepatocellular carcinoma after azathioprine treatment in a patient with ulcerative colitis

We report the case of a 66-year-old male with ulcerative colitis diagnosed in 1987, who had been treated with azathioprine (AZA) for the past two years (average dose about 1.6 mg/kg/day). In May 1999 he presented with painless jaundice, fatigue and recent weight loss. Cholestatic enzymes were elevated, alpha-fetoprotein was normal and hepatitis B/C serology negative. After diagnosis of veno-occlusive disease (VOD) and hepatocellular carcinoma (HCC) via biopsy, tumour resection was performed. The histology was typical for a well-differentiated HCC with trabecular and pseudoglandular structures. Neighbouring liver tissue was atrophic, with nodular regenerative hyperplasia (NRH), peliosis-like sinusoidal ectasias and intra-sinusoidal accumulation of blood, associated with peri-sinusoidal fibrosis. Although none of the well-established risk factors for HCC such as cirrhosis, hepatitis B/C, metabolic liver disease or toxins were present, this patient developed HCC. This and previous reports suggest that NRH and/or VOD associated with AZA represent a risk factor for HCC. AZA should therefore not only be stopped in patients with NRH/VOD but patients should also be screened for HCC.

[Oral immunization against classical swine fever (CSF) in the Federal State of Brandenburg from 1995 to 1997]

The first findings of classical swine fever in wild boar occurred in the rural district Ostprignitz-Ruppin of Brandenburg in March 1995. Up to this time the area was considered to be free of swine fever in domestic and wild boars. The swine fever cases were marked particularly by the occurence of dead games and clinically decreased individuals as well as by the involvement of young wild boars. (< 10 kg carcass weight). In Brandenburg, the eradication programme of classical swine fever was based on oral immunization with an attenuated type C vaccine (so called Dessauer wild boar lure) carried out within the frame of a field trial since 1995. The success of oral immunization was examined by the development of swine fever positive-findings within the swine fever endangered district and by the seroconversion in the entire vaccination area. Due to the oral immunization the classical swine fever prevalence decreased from 4.65% in March 1995 to 0.58% in December 1997. After the third immunization the seroconversion reached on average rates between 30% and 35%. The seroconversion increased with carcass weight and with number of subsequent immunization. During the investigation period the rate of seroconversion in wild boars up to 17 kg carcass weight was 13.2%, in wild boars from 18 to 28 kg carcass weight 23.1%, sub-adult wild boars from 29 to 56 kg carcass weight 33.2%, and the adult wild boars above 57 kg carcass weight 41.5%.

Temporal coherence of individual turbulent patterns in atmospheric seeing

We used a variation of the generalized scidar (scintillation detection and ranging) technique to examine the temporal coherence of turbulent patterns at different altitudes in the atmosphere above Palomar Observatory. This enables us to test the validity of a frozen turbulence hypothesis in the local reference frame of the moving atmosphere. The data set analyzed here contains three turbulent patterns, each at a different altitude, which remain internally coherent over time scales of 0.28-0.41 s. This measurement is significant, because it is made on a 5-m aperture, allowing moving patterns to be tracked over time scales longer than their own lifetimes.

A new form of Filgrastim with sustained duration in vivo and enhanced ability to mobilize PBPC in both mice and humans

Granulocyte colony-stimulating factor (G-CSF) has proven effective in the prophylaxis of chemotherapy-induced neutropenia and as a mobilizer of peripheral blood progenitor cells. The longevity of G-CSF action is limited by its removal from the body by two mechanisms. The first is thought to be mediated via receptors (receptor mediated clearance [RMC]) predominantly on neutrophils, the second process is likely the result of renal clearance. With the intention of developing a novel form of Filgrastim (r-met HuG-CSF) with a sustained duration of action in vivo, a new derivative named SD/01 has been made by association of Filgrastim with poly(ethylene glycol). The desired properties of this new agent would include a prolonged duration of action sufficient to cover a complete single course of chemotherapy. SD/01 is shown here to sustain significantly elevated neutrophil counts in hematopoietically normal mice for 5 days. In neutropenic mice effects were noted for at least 9 days, accompanying a significant reduction in the duration of chemotherapy induced neutropenia. Normal human volunteers showed higher than baseline ANC for around 9 to 10 days after a single injection of SD/01. Data from these normal volunteers also indicate that mobilization of CD34+ cells and progenitors may occur in a more timely manner and to around the same absolute numbers as with repeated daily injections of unmodified Filgrastim. These data indicate that SD/01 represents an efficacious novel form of Filgrastim with actions sustained for between one and two weeks from a single injection.

Incidence of classical swine fever (CSF) in wild boar in a densely populated area indicating CSF virus persistence as a mechanism for virus perpetuation

A virological survey was carried out to establish the distribution of classical swine fever (CSF) virus among wild boar in the Federal State of Brandenburg, Germany. Organ materials and blood samples were collected from 11,670 wild boar shot or found dead during the period March 1995 to December 1997. In total 211 (1.8%) wild boar were positive for CSF virus or antigen. The incidence of CSF-positive animals decreased continuously from 4.6% at the beginning of the epidemic in 1995 to 0.7% in 1997. The highest incidence of positive animals (22%) was found in wild-boar piglets younger than 3 months of age in 1995. The findings were indicative for the decisive role which young wild boar play in the epidemiology of CSF. Following intrauterine transfer some of the wild-boar piglets were probably persistently infected with CSF virus as experienced experimentally. Such piglets can be held responsible for CSF virus perpetuation within the wild-boar population. No CSF virus was isolated from adult wild boar weighing more than 75 kg. During 3 years of monitoring a sufficient number of susceptible wild boar, in particular young animals, was available to maintain the infection chain in that area. It was concluded that persistently infected piglets and the high population density of wild boar in the Brandenburg region offered optimal conditions for the establishment of an CSF epidemic.

Minimization of CD34+ cell enumeration variability using the ProCOUNT standardized methodology

The dose of cells expressing the surface antigen CD34 (CD34+) has been shown to be a reliable predictor of the time to engraftment following transplantation of PBPC to support high-dose chemotherapy. However, evaluation of rare cells is complicated by a number of factors, including the variability in operator and technical procedures. Recently, Becton Dickinson Immunocytometry Systems introduced a new CD34+ cell analysis system, the ProCOUNT cell enumeration kit, which automates the analysis of CD34+ cells and minimizes the variabilities of this procedure. We have evaluated the ProCOUNT system in comparison to a standard CD34 cell analysis (based on the Milan approach) using leukapheresis products from patients and normal donors mobilized with chemotherapy plus recombinant human G-CSF (rhG-CSF) or with rhG-CSF alone. In addition, we compared these analyses using CD34+ cell-selected mobilized leukapheresis products with purities of 75% or greater. The standard CD34 cell analysis methodology quantitated the frequency of cells identified as CD45+, low side scatter, and CD34+. A high correlation coefficient was obtained between the ProCOUNT methodology and the standard CD34 cell analysis methodology for cells obtained from leukapheresis products mobilized with chemotherapy plus rhG-CSF (r = 0.98), rhG-CSF alone (r = 0.96), and CD34+-selected mobilized leukapheresis products (r = 0.83). A comparison was also made between technicians using both analysis methods. Whereas the correlation coefficient between two technicians using the standard methodology was r = 0.77, the correlation coefficient was much higher when using ProCOUNT (r = 0.99). These data demonstrate that the use of ProCOUNT is associated with less variability between data analyzed by different operators. Also, ProCOUNT is consistent with existing CD34+ cellular analysis methodologies. An additional advantage is the ability to determine the absolute concentration of CD34+ cells, thereby allowing calculation of total CD34+ cell numbers without using WBC counts, which also have inherent errors. The ProCOUNT system provides an automated analysis procedure that minimizes the variables in CD34+ cell analysis and may be useful for standardization of methodology between laboratories.

Large-scale isolation of CD34+ cells using the Amgen cell selection device results in high levels of purity and recovery

The Amgen Cell Selection Device (ACSD) is a fully automated system based on the research scale magnetic-activated cell separation (MACS) system (Miltenyi Biotech GmbH, Bergisch Gladbach, Germany) for the selection of CD34+ cells. Leukapheresis products (LP) (n = 30) from normal donors mobilized with recombinant human granulocyte colony-stimulating factor (rhG-CSF) were selected with the ACSD to evaluate the performance of this system. The starting LP contained a median of 0.51% CD34+ cells (range 0.21%-1.54%) and a median WBC count of 3.0 x 10(10) (range 1-4.7 x 10(10) cells). After selection on the ACSD a mean purity of 91.5% +/- 0.6% CD34+ cells was obtained, with a median purity of 95.5% CD34+ cells. A median of 98 x 10(6) total CD34+ cells were recovered postselection, with a range of 31-323 x 10(6) cells collected from the LP. This represented a mean recovery of 81.7% +/- 6% of CD34+ cells and a median of 78% compared with starting CD34+ cell numbers in the LP. FACS analysis of the selected products demonstrated a 4-5 log depletion of T cell subsets, including CD3, CD4, CD8, and CD56 subsets. These data demonstrate the high performance obtained with the ACSD resulting in a final product of greater than 90% purity of CD34+ cells. CD34+ cells selected with the ACSD represent an ideal product for clinical applications, such as tumor cell purging, T cell depletion for allogeneic transplant, ex vivo expansion, and gene therapy.

UVA-induced inhibition of proliferation of PHA-stimulated lymphocytes from humans treated with 8-methoxypsoralen

Lymphocytes from healthy human donors were used as a model system for studying the combined effect of 8-methoxypsoralen (8-MOP) plus UVA. Two hours after oral administration of therapeutic doses of the drug enough 8-MOP was taken up in vivo by the circulating peripheral lymphocytes to cause significant inhibition of phytohaemagglutinin induced lymphocyte proliferation when the cells were exposed in vitro to UVA irradiation. The inhibition of proliferation as monitored by a reduced 3H-thymidine incorporation into cellular DNA was shown to be UVA-dose dependent. Control cultures of 8-MOP containing lymphocytes which were not UVA irradiated showed normal blast transformation. In lymphocytes obtained from the same donors prior to 8-MOP intake, PHA-induced lymphocyte transformation was not impaired by UVA irradiation. In 8-MOP containing lymphocytes exposed repeatedly to UVA during the 72 h culture period a cumulative effect of irradiation could be observed. A varying sensitivity towards 8-MOP plus UVA was noted when the cells were irradiated at different times after PHA stimulation. The cells were most vulnerable to UVA irradiation during the DNA-synthesis phase of the proliferating lymphocytes. The results suggest that dermal inflammatory infiltrates containing locally proliferating lymphocytes are influenced by systemic photochemotherapy since UVA penetrates well into the dermis.

The human peripheral lymphocyte--a model system for studying the combined effect of psoralen plus black light

The effect of psoralen plus long wavelength ultraviolet light (UVA) on 3H-thymidine uptake of PHA stimulated human lymphocytes was investigated. PHA induced lymphocyte transformation was inhibited by the combined action of psoralen and UVA irradiation in a dose related manner. Inhibition of DNA-synthesis occurred at concentrations of psoralen that can be expected in the serum of patients treated by systemic photochemotherapy. No effect was noted at these psoralen concentrations in the absence of UVA irradiation. Also did UVA irradiation in the absence of psoralen not inhibit 3H-thymidine incorporation into PHA stimulated lymphocytes.