European expert consensus statement on the systemic treatment of alopecia areata.

Alopecia areata is an autoimmune form of non-scarring hair loss. It is usually characterized by limited areas of hair loss. However, the disease may progress to complete scalp and body hair loss (alopecia totalis, alopecia universalis). In patients with alopecia areata hair loss significantly impacts the quality of life. Children and adolescents with alopecia areata often experience bullying, including physical aggression. The disease severity evaluation tools used in clinical practice are: the Severity of Alopecia Tool (SALT) score and the Alopecia Areata Scale (AAS). A SALT score equal to or greater than 20 constitutes a commonly accepted indication for systemic therapy in alopecia areata. When using the AAS, moderate to severe alopecia areata should be considered a medical indication for systemic treatment. Currently, the only two EMA-approved medications for alopecia areata are baricitinib (JAK 1/2 inhibitor) for adults and ritlecitinib (JAK 3/TEC inhibitor) for individuals aged 12 and older. Both are EMA-approved for patients with severe alopecia areata. Other systemic medications used off-label in alopecia areata include glucocorticosteroids, cyclosporine, methotrexate and azathioprine. Oral minoxidil is considered an adjuvant therapy with limited data confirming its possible efficacy. This consensus statement is to outline a systemic treatment algorithm for alopecia areata, indications for systemic treatment, available therapeutic options, their efficacy and safety, as well as the duration of the therapy.

Consensus statement on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: Localized scleroderma, systemic sclerosis and overlap syndromes.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present consensus provides an update to the 2017 European Dermatology Forum Guidelines, focusing on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, updated strategies for the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this consensus provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes.

Genomic testing for copy number and single nucleotide variants in spermatogenic failure.

PURPOSE: To identify clinically significant genomic copy number (CNV) and single nucleotide variants (SNV) in males with unexplained spermatogenic failure (SPGF). MATERIALS AND METHODS: Peripheral blood DNA from 97/102 study participants diagnosed with oligozoospermia, severe oligozoospermia, or non-obstructive azoospermia (NOA) was analyzed for CNVs via array comparative genomic hybridization (aCGH) and SNVs using whole-exome sequencing (WES). RESULTS: Of the 2544 CNVs identified in individuals with SPGF, > 90% were small, ranging from 0.6 to 75 kb. Thirty, clinically relevant genomic aberrations, were detected in 28 patients (~ 29%). These included likely diagnostic CNVs in 3/41 NOA patients (~ 7%): 1 hemizygous, intragenic TEX11 deletion, 1 hemizygous DDX53 full gene deletion, and 1 homozygous, intragenic STK11 deletion. High-level mosaicism for X chromosome disomy (~ 10% 46,XY and ~ 90% 47,XXY) was also identified in 3 of 41 NOA patients who previously tested normal with conventional karyotyping. The remaining 24 CNVs detected were heterozygous, autosomal recessive carrier variants. Follow-up WES analysis confirmed 8 of 27 (30%) CNVs (X chromosome disomy excluded). WES analysis additionally identified 13 significant SNVs and/or indels in 9 patients (~ 9%) including X-linked AR, KAL1, and NR0B1 variants. CONCLUSION: Using a combined genome-wide aCGH/WES approach, we identified pathogenic and likely pathogenic SNVs and CNVs in 15 patients (15%) with unexplained SPGF. This value equals the detection rate of conventional testing for aneuploidies and is considerably higher than the prevalence of Y chromosome microdeletions. Our results underscore the importance of comprehensive genomic analysis in emerging diagnostic testing of complex conditions like male infertility.

Therapeutic management in paediatric alopecia areata: A systematic review.

Alopecia areata is the third most common cause of dermatology consultations in children but the treatment of paediatric alopecia areata remains challenging. A systematic review of the literature about the treatment of alopecia areata in children (≤18 years old) was performed on 11 May 2020 by searching the PubMed, Scopus and EBSCO databases. The terms used for the search were: 'alopecia areata', 'alopecia totalis' or 'alopecia universalis' combined with 'paediatric', 'children' or 'childhood'. A total of 89 articles were included in final evaluation. The most commonly assessed treatment options in paediatric alopecia areata were topical immunotherapy (response rate in monotherapy: 54%; 187/345) intralesional glucocorticosteroids (75%; 211/280), systemic glucocorticosteroids (73%; 102/140), and anthralin (42%; 31/74). Topical glucocorticosteroids (81%; 35/43), systemic Janus kinase (JAK) inhibitors (90%; 27/30), topical calcineurin inhibitors (42%; 8/19), topical JAK inhibitors (65%; 11/17), PUVA therapy (56%; 9/16) and 308-nm excimer laser (77%; 10/13) were also evaluated. Additionally, evaluation in smaller numbers of paediatric patients included methotrexate (100%; 10/10), topical minoxidil (44%; 4/9) and cyclosporine (83%; 5/6). There were limited data considering children with alopecia areata treated with azathioprine, hydroxychloroquine, topical sildenafil, topical prostaglandin analogues, fractional carbon dioxide laser, leflunomide, mesalazine, apremilast, dupilumab, ustekinumab, efalizumab, botulinum toxin, and compound glycyrrhizin. On the basis of the limited data available glucocorticosteroids (systemic, intralesional or topical) and JAK inhibitors (systemic or topical) may be considered the best documented and most effective treatment options in alopecia areata in children. There are no sufficient paediatric data to compare treatment safety and relapse rates in these therapeutic modalities.

Assessment of the bacterial viability of chlorine- and quaternary ammonium compounds-treated Lactobacillus cells via a multi-method approach.

AIMS: The assessment of the bacterial viability of chlorine- and quaternary ammonium compounds (QACs)-treated Lactobacillus cells by culture-dependent and -independent methods. METHODS AND RESULTS: Lactobacillus isolates (Lactobacillus plantarum G1, Lactobacillus plantarum B1, Lactobacillus brevis S1 and Lactobacillus paracasei W1) in biofilm and planktonic cell suspensions were treated with chlorine-based (0·018 and 0·18%) and QACs-based (0·2 and 2·0%) disinfectants for 5 min and then analysed by plate counting, flow cytometry (FCM) and fluorescence activated cell sorting (FACS). The reaction of sessile cells to disinfectants was assessed with the confocal laser scanning microscopy (CLSM). Plate counts revealed L. paracasei W1 to be substantially inactivated by both disinfectants, while counts of the other isolates to be significantly reduced only by QACs, with L. plantarum B1 and L. brevis S1 showing a greater difference between QACs concentrations and cell types. In several cases, the disinfectants caused slightly higher inactivation of planktonic than biofilm cells, with L. plantarum B1 being significantly less sensitive to QACs in biofilm cells (P < 0·05). Following FCM with a Syto® 9/PI assay, which addresses cell membrane integrity, the emergence of damaged (Syto® 9- PI+ ) and injured (Syto® 9+ PI+ ) subpopulations was often observed in cells when they were treated with QACs, whereas intact (Syto® 9+ PI- ) and unstained (Syto® 9- PI- ) subpopulations were mostly encountered in chlorine-treated cells. Except Syto® 9- PI+ , all subpopulations were recovered on agar plates following FACS, with biofilm cells showing higher culturability irrespective of conditions, probably because of the residues of the biofilm matrix which serve as a protective cover for the bacteria. The CLSM revealed a substantial cell membrane damage within the QACs-treated biofilms, however, some cells deep in the biofilm were still intact and thus remained protected against this disinfectant. CONCLUSION: We found that FCM/FACS proved useful in the analysis of lactobacilli membrane integrity in disinfection experiments as well as in recovery evaluation of planktonic-biofilm cell subpopulations. In turn, CLSM was particularly useful in investigating the resistance mechanism when Lactobacillus cells were embedded in biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights the need for treatment optimization on a case-by-case basis to avoid the emergence of cells in intermediate states with recovery potential and to reach and, thus, kill all bacteria in already developed lactobacilli biofilms.

Increased risk of severe course of pemphigus in patients with pemphigus-associated alopecia: a prospective observational study.

BACKGROUND: Pemphigus-associated alopecia is considered rare, and has not been studied in detail. AIM: To evaluate the clinical and immunological characteristics of patients with pemphigus-associated alopecia. METHODS: This prospective observational study included 80 consecutive patients with histopathologically and immunopathologically confirmed pemphigus, of whom 11 (13.8%) were found to have pemphigus-associated alopecia. Alopecia was observed in 11/52 patients with pemphigus and scalp involvement: [0/28 (35.7%) with pemphigus vulgaris and 1/24 (4.2%) with pemphigus foliaceus. The clinical and immunological characteristics of these patients were analysed. RESULTS: Patients with pemphigus-associated alopecia had a significantly higher Pemphigus Disease Area Index total activity score compared with patients who had no pemphigus-associated alopecia (21.8 ± 18.6 and 11.0 ± 20.5, respectively; P = 0.02). Mean serum anti-desmoglein (Dsg)1 antibody concentration was 141.8 ± 66.9 U/mL and 60.0 ± 52.6 U/mL, respectively (P = 0.03), and mean serum anti-Dsg3 concentration was 126.6 ± 36.7 U/mL and 67.4 ± 52.5 U/mL, respectively (P = 0.03). The values for achieving serological remission were 10% and 70%, respectively (P = 0.02). CONCLUSIONS: Pemphigus-associated alopecia is a marker of severe disease and a treatment-resistant disease course.

Claudin-3 - a new intestinal integrity marker in patients with psoriasis: association with disease severity.

BACKGROUND: Gut dysbiosis and increased intestinal permeability play a significant role in the pathogenesis of psoriasis and its comorbidities. Claudin-3 is a key component of tight junctions, which may serve as marker of gut barrier integrity. OBJECTIVES: The aim of the study was to investigate circulating plasma claudin-3 in patients with psoriasis and to evaluate clinical and metabolic factors, which determine its concentration. METHODS: This cross-sectional study included 60 patients with psoriasis (39 men and 21 women, mean age: 45.6 ± 12.1 years) and 30 healthy controls (18 men and 12 women, mean age: 46.3 ± 15.5 years) age, sex and body mass index-matched. Plasma claudin-3 concentration was measured using an enzyme-linked immunosorbent assay. RESULTS: Plasma claudin-3 concentration was significantly higher in patients with psoriasis in comparison with healthy control [median (interquartile range), 50.7 ng/mL (47.3-54.2) vs. 43.3 ng/mL (42.3-44.2), P < 0.001]. Patients who achieved ΔPASI90 response after 16 weeks of treatment showed tendency to decrease in circulating claudin-3 plasma concentration. Positive correlations between claudin-3 concentration and the PASI score (r = 0.828; P < 0.001) as well as claudin-3 and neutrophil-to-lymphocyte ratio (r = 0.847; P < 0.001) were found. A multivariable linear regression analysis confirmed association of claudin-3 with the PASI score (P < 0.001), neutrophil-to-lymphocyte ratio (P < 0.01) and active smoking (P < 0.05). CONCLUSION: Claudin-3, a biomarker for gut permeability, is increased in psoriasis and correlates with disease severity and smoking. Further investigations are needed to determine whether reinforcing intestinal barrier may be a new therapeutic target in psoriasis.

The value of dermoscopy in diagnosing eyebrow loss in patients with alopecia areata and frontal fibrosing alopecia.

INTRODUCTION: Alopecia areata and frontal fibrosing alopecia are common causes of eyebrow loss (madarosis). OBJECTIVE: Assessment of trichoscopic markers of eyebrow loss in alopecia areata and frontal fibrosing alopecia. MATERIALS AND METHODS: The analysis included 50 patients with scalp alopecia areata with madarosis, 50 patients with scalp frontal fibrosing alopecia with madarosis and 50 healthy controls. In every case, trichoscopy of the eyebrow area was performed. RESULTS: Empty follicular and eccrine duct openings were observed in all patients and presented predominantly as yellow dots. Exclamation mark hairs were only detected in patients with alopecia areata (30%). Tapered hairs, broken hair, black dots and Pohl-Pinkus constrictions were observed in 14%, 36%, 26% and 4% of patients with alopecia areata, respectively, 4%, 16%, 2% and 0% of patients with frontal fibrosing alopecia, respectively, and they were not present in healthy controls. Dystrophic hairs and whitish areas were observed only in patients with frontal fibrosing alopecia (28% and 32%, respectively). Eyebrow regrowth in distinct directions was present in 32% of patients with frontal fibrosing alopecia, 8% of patients with alopecia areata and 4% of healthy controls. Diffuse erythema was detected in 60% of patients with alopecia areata and frontal fibrosing alopecia and 56% of healthy controls. Vellus hairs and upright regrowing hairs were observed in patients with alopecia areata (62% and 58%, respectively), frontal fibrosing alopecia (60% and 84%, respectively) and healthy controls (100% and 100%, respectively). CONCLUSION: Trichoscopy of the eyebrow area is useful in diagnosing patients with isolated eyebrow loss. The most characteristic trichoscopic features of eyebrow loss in alopecia areata include exclamation mark hairs, tapered hairs, broken hairs and black dots. Frontal fibrosing alopecia of the eyebrows is characterized by the presence of dystrophic hairs, white areas and eyebrow regrowth in distinct directions.

Efficacy of perilesional and intralesional triamcinolone acetonide injections in pemphigus vulgaris lesions of the scalp: an effective therapeutic option.

The scalp is a common location for pemphigus vulgaris (PV), and scalp lesions may be resistant to standard treatment. Perilesional/intralesional triamcinolone acetonide (TA) injections have been used successfully to treat oropharyngeal and ocular involvement in PV. Data on the efficacy of perilesional and intralesional triamcinolone acetonide injections in scalp lesions in PV are lacking. We report two patients with immunopathologically and histopathologically confirmed PV and residual scalp lesions resistant to standard treatment, who were treated with perilesional and intralesional injections of TA 10 mg/mL. Clearance of scalp lesions was achieved after one after, respectively, one and two perilesional and intralesional injections. Perilesional and intralesional TA injections may serve as an effective and safe treatment for recalcitrant scalp lesions in pemphigus.

European dermatology forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 2: Scleromyxedema, scleredema and nephrogenic systemic fibrosis.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 2 of this guideline provides clinicians with an overview of the diagnosis and treatment of scleromyxedema, scleredema (of Buschke) and nephrogenic systemic sclerosis (nephrogenic fibrosing dermopathy).

European Dermatology Forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: localized scleroderma, systemic sclerosis and overlap syndromes.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this guideline provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes of systemic sclerosis with diseases of the rheumatological spectrum.

Reflectance confocal microscopy as a non-invasive diagnostic tool for Hailey-Hailey disease.

BACKGROUND/PURPOSE: Reflectance confocal microscopy (RCM) is a non-invasive method for high-resolution, in vivo imaging of the epidermis and upper dermis. The purpose of the study was to evaluate the potential usefulness of RCM as a non-invasive diagnostic tool for Hailey-Hailey disease (familial benign chronic pemphigus). METHODS: Four patients with Hailey-Hailey disease were examined by RCM. Subsequently, punch biopsies were taken to compare RCM images with corresponding histopathologic findings. RESULTS: On RCM images, the most sticking feature was acantholysis at the level of the granular and spinous layer, resembling a 'dilapidated brick wall'. We suggest the term 'dilapidated brick wall RCM sign' to describe this feature and to distinguish from the corresponding histopathology finding. Other RCM features included: epidermal disarray, intraepidermal clefts, inflammatory cells in the epidermis and in the superficial dermis. These RCM abnormalities correlated with analogous histopathology findings. CONCLUSION: Reflectance confocal microscopy is a promising non-invasive diagnostic tool for Hailey-Hailey disease. The method may also be considered useful for choosing the best site for biopsy, which may aid pathology evaluation and spare time needed to establish the diagnosis.

An assessment of the usefulness of a coconut as a model of the human skull for forensic identification of a homicide weapon.

The authors made an attempt to verify if a coconut can be used as a model of human skull to determine the homicide weapon. During our experiment 27 strike attempts were performed with the use of 9 different tools. Among them there were authentic murder weapons and instruments which had been used in similar experiments conducted on human skulls in 1955. Depending on the size of an area in contact with a coconut, weapons caused dents corresponding to the shape of a weapon, irregular fractures or long linear cracks. Our results have shown that coconut can be used as an inexpensive screening model of human skull, but only to determine fractures made by tools with small striking surface.

'Black dots' seen under trichoscopy are not specific for alopecia areata.

BACKGROUND: 'Black dots' are macrocomedo-like round structures localized to the follicular ostium, and are considered a specific trichoscopic feature of alopecia areata (AA). AIM: To characterize specific features of 'black dots', and assess their possible presence in common hair and scalp disorders. METHODS: In total, 107 patients with hair loss [30 with alopecia areata (AA), 37 with androgenetic alopecia (AGA), 17 with chronic telogen effluvium (TE), 23 with other hair and scalp diseases] and 93 healthy controls were examined, using a videodermoscope with 20-70 times magnification. RESULTS: There was a correlation between the black dots and the early acute phase of the various alopecia types with the presence of the black dots. Black dots were found in 11% (22/107) of patients with hair loss, including 53.3% (16/30) with AA; in 40% (2/5) of patients with severe chemotherapy-induced alopecia, and in 100% of patients with dissecting cellulitis of the scalp (n = 2), hypotrichosis simplex (n = 1), and congenital aplasia cutis (n = 1). No black dots were seen in patients with AGA or TE. CONCLUSIONS: Black dots are not specific for AA, and may be present in other hair and scalp diseases.

Avian influenza viruses in wild birds at the Jeziorsko reservoir in Poland in 2008-2010.

During a 3-year surveillance study for avian influenza virus (AIV) infections at the Jeziorsko reservoir in central Poland, 549 oropharyngeal or cloacal swabs from 366 birds of 14 species belonging to 3 orders (Anseriformes, Charadriiformes and Gruiformes) were tested. AIV was detected in 14 birds (3.8%): Common Teals (12x), Mallard (1x) and Garganey (1x). Three potentially dangerous H5 AIV were detected in Common Teals (2x) and Garganey (1x) but all of them revealed a low pathogenic pathotype. A unique cleavage site amino acid motif PQREIR*GLF was found in one H5 isolate from a Garganey.

Plasma concentrations of TNF-alpha and its soluble receptors sTNFR1 and sTNFR2 in patients with coronary artery disease.

Tumour necrosis factor alpha (TNF-alpha) is implicated in post-ischemic myocardial dysfunction. Two distinct TNF-alpha receptors are shed from cell membranes and circulate in plasma as soluble sTNFR1 and sTNFR2 proteins. The aim of the study was to establish factors associated with plasma concentrations of TNF-alpha and its receptors in patients with coronary artery disease (CAD). Since adenosine inhibits the expression of TNF-alpha, two functional polymorphisms in genes encoding enzymes participating in adenosine metabolism, i.e. AMP deaminase-1 (AMPD1, C34T) and adenosine deaminase (ADA, G22A), were analyzed. Plasma concentrations of TNF-alpha, sTNFR1, and sTNFR2 were measured using ELISA in 167 patients with CAD. Common factors significantly associated with higher TNF-alpha, sTNFR1, and sTNFR2 were lower glomerular filtration rate (GFR), older age, higher BNP, lower blood haemoglobin, and the presence of asthma or chronic obstructive pulmonary disease (COPD). Higher TNF-alpha and sTNFR1 concentrations were also associated with the presence of heart failure (HF), lower ejection and shortening fraction, the presence of diabetes or metabolic syndrome, lower serum HDL cholesterol, and higher uric acid. In multivariate analysis the common independent predictors of higher TNF-alpha, sTNFR1, and sTNFR2 were lower GFR, lower HDL cholesterol, higher BNP, and the presence of asthma or COPD. There were no associations between AMPD1 C34T or ADA G22A genotypes and TNF-alpha or its receptors. In conclusion, the concentrations of TNF-alpha, sTNFR1, and sTNFR2 reflect the impairment of cardiac and renal function in patients with CAD. Metabolic syndrome and diabetes are associated with higher plasma concentrations of TNF-alpha and its receptors.

Circulating adhesion molecules and purine nucleotides during kidney allograft reperfusion.

The impairment of organ function due to ischemia-reperfusion injury is still an important problem in solid organ transplantation. Numerous experimental and clinical studies of native organs have shown that ischemia-reperfusion constitutes an acute inflammatory process involving cell surface adhesion molecule expression. These markers are crucial for the recruitment and infiltration of effector cells into the postischemic tissue. Purines released by the postischemic tissue as the products of the degradation of high-energy nucleotides can be regarded as markers of disturbed energy metabolism. The aim of this study was to examine the correlation between circulating adhesion molecules and purine metabolites in graft renal vein plasma during 49 cases of kidney reperfusion. E-selectin, ICAM-1, and VCAM-1 concentrations correlated positively with hypoxanthine concentrations during reperfusion, whereas the concentrations of ICAM-1 correlated negatively with xanthine concentrations. The results of the present study suggested that the concentrations of adhesion molecules in the renal vein during reperfusion correlated with purine metabolites, reflecting metabolic changes in renal tissue.

Adropin, nesfatin-1 and angiotensin II receptor expression in the abdominal aorta in ovariectomized rats after nesfatin-1 treatment.

The aim of the research was to assess the effect of nesfatin-1 on the structure, flexibility parameters, and expression of adropin, nesfatin-1, and angiotensin II receptor type 1 (AT1R) in the abdominal aorta in ovariectomized rats. Fragments of aortas were collected after euthanasia of female sham-operated (CONT) and ovariectomized Wistar rats (EXP), which were administered intraperitoneal injection of physiological saline (CONT, n = 7; EXP-O, n = 7) or nesfatin-1 (EXP-N, n = 7) in an amount of 2 µg/kg b.w. once a day for 8 weeks. The samples of aortas were collected for measurement of elasticity as well as histomorphometric, immunohistochemical, FTIR, and Raman spectroscopy analysis. The ovariectomy caused a significant increase in the thickness of the total wall and its particular layers in the aorta, in comparison to the CONT and EXP-N groups. However, the ovariectomy led to a decrease in the amount of elastin, collagen (mature, immature collagen, collagen maturity ratio 1660 - 1690 cm-1), and amides, with a simultaneous increase in lipids, especially in the tunica intima-media of the abdominal aorta compared to the other groups. The use of nesfatin-1 significantly increased the amount of collagen, elastin and amides with a simultaneous decrease in the amount of lipids and the expression of AT1R, adropin and nesfatin-1 in the abdominal aorta of ovariectomized rats. In conclusion, our study showed that the ovariectomy surgery induced changes in the abdominal aorta wall characteristic for aging females. Application of nesfatin-1 may prevent the negative consequences in the vessel wall structure in females in conditions of estrogen deficiency and prevent atherosclerotic changes in the cardiovascular system.

Quantitative analysis of clinically relevant mutations occurring in lymphoid cells harboring gamma-retrovirus-encoded hsvtk suicide genes.

The in vivo regulation of T lymphocyte activity by the activation of a suicide mechanism is an essential paradigm for the safety of adoptive cell therapies. In light of reports showing that gamma-retroviral vector-encoded herpes simplex virus thymidine kinase (hsvtk) undergoes recombination, we undertook a thorough investigation of the genomic stability of SFG-based vectors using two variants of the wild-type hsvtk gene. In a large panel of independent clones, we demonstrate that both hsvtk genes undergo recombination with molecular signatures indicative of template switching in GC-rich regions displaying homology at the deletion junctions or RNA splicing. In the absence of ganciclovir selection, the frequency of recombination is 3% per retroviral replication cycle. Our results underscore the importance of the five nucleotide difference between the two hsvtk genes that account for the presence of recombinogenic hot spots in one variant and not the other, indicating that the probability of RNA splicing is influenced by minute nucleotide changes in sequences adjacent to the splice donor and acceptor sites. Furthermore, our mutational analysis in an unbiased panel of human lymphoid cells (that is, without immune or ganciclovir-mediated selective pressure) provides a robust in vitro assay to predict and quantify clinically relevant mutations in hsvtk suicide genes, which can be applied to studying and improving the stability of any transgene expressed in gamma-retroviral or lentiviral vectors.

Comparison of human erythrocyte purine nucleotide metabolism and blood purine and pyrimidine degradation product concentrations before and after acute exercise in trained and sedentary subjects.

This study aimed at evaluating the concentration of erythrocyte purine nucleotides (ATP, ADP, AMP, IMP) in trained and sedentary subjects before and after maximal physical exercise together with measuring the activity of purine metabolism enzymes as well as the concentration of purine (hypoxanthine, xanthine, uric acid) and pyrimidine (uridine) degradation products in blood. The study included 15 male elite rowers [mean age 24.3 ± 2.56 years; maximal oxygen uptake (VO2max) 52.8 ± 4.54 mL/kg/min; endurance and strength training 8.2 ± 0.33 h per week for 6.4 ± 2.52 years] and 15 sedentary control subjects (mean age 23.1 ± 3.41 years; VO2max 43.2 ± 5.20 mL/kg/min). Progressive incremental exercise testing until refusal to continue exercising was conducted on a bicycle ergometer. The concentrations of ATP, ADP, AMP, IMP and the activities of adenine phosphoribosyltransferase (APRT), hypoxanthine-guanine phosphoribosyltransferase (HGPRT) and phosphoribosyl pyrophosphate synthetase (PRPP-S) were determined in erythrocytes. The concentrations of hypoxanthine, xanthine, uric acid and uridine were determined in the whole blood before exercise, after exercise, and 30 min after exercise testing. The study demonstrated a significantly higher concentration of ATP in the erythrocytes of trained subjects which, in part, may be explained by higher metabolic activity on the purine re-synthesis pathway (significantly higher PRPP-S, APRT and HGPRT activities). The ATP concentration, just as the ATP/ADP ratio, as well as an exercise-induced increase in this ratio, correlates with the VO2max level in these subjects which allows them to be considered as the important factors characterising physical capacity and exercise tolerance. Maximal physical exercise in the group of trained subjects results not only in a lower post-exercise increase in the concentration of hypoxanthine, xanthine and uric acid but also in that of uridine. This indicates the possibility of performing high-intensity work with a lower loss of not only purine but also pyrimidine.