A steady-state kinetic interface-sensitive tracer (KIS-SST) method to measure capillary associated interfacial area in a simultaneous co-flow condition

We propose a novel method to measure the specific capillary-associated interfacial area (a_wn) between non-wetting and wetting fluids by applying kinetic interface-sensitive (KIS) tracers under steady-state two-phase co-flow conditions. Seven column experiments were conducted with a column filled with glass beads (diameter d₅₀ = 170 μm), serving as the solid grain network of a porous granular material. The experiments were performed for two flow scenarios, i.e., five experiments were performed for drainage conditions (increasing non-wetting saturation) and two experiments for imbibition conditions (increasing wetting saturation). To obtain different saturation levels in the column and, consequently, different capillarity-induced interfacial areas between the fluids, the experiments were performed for different fractional flow ratios (i.e., the ratio between injection rate of the wetting phase and total injection rate). The concentrations of the KIS tracer reaction by-product were recorded at each saturation level and the corresponding interfacial area was calculated. As a result of the fractional flow condition a wide range of wetting phase saturation is created (0.3 < S_w < 0.8). The measured a_wn increases with decreasing wetting phase saturation for the range 0.55 < S_w < 0.8, and then is followed by a drop in wetting phase saturation of 0.3 < S_w < 0.55. A good fit for our calculated a_wn is obtained (RMSE <0.16) using a polynomial model. Additionally, the results of the proposed method are compared to published experimental data and the method's main advantages and limitations are discussed.

Comparison of the antiarrhythmic potential of doxapram and its metabolite ketodoxaparam

Background

A few years ago, the TASK-1 channel has been established as a potential new target for the therapy of atrial fibrillation (AF). In the heart, TASK-1 is almost exclusively expressed in the atria and is significantly upregulated in AF patients. Therefore, it plays an important role in the shortening of the atrial action potential observed during AF, making TASK-1 a promising target for AF therapy. This could be proven in a porcine model of persistent AF in which an intravenous application of the TASK-1 inhibitor doxapram led to a termination of AF and the restoration of sinus rhythm (SR). Doxapram's metabolite ketodoxapam is described in the literature as being active with limited data available on its usage. Therefore, the effect of ketodoxapram on TASK-1 and its possible use in AF therapy still needs to be investigated.

Purpose

The purpose of the present study was to assess the potential of ketodoxapram in the termination of AF. Furthermore, a comparison between doxapram and ketodoxapram was performed based on electrophysiological and pharmacological data.

Methods

UPLC-MS/MS assays were developed and validated for the measurement of doxapram and ketodoxapram in porcine plasma and brain tissue. Using these assays, the pharmacokinetics of both substances, after intravenous injections of 1 mg/kg, were determined in pigs. Furthermore, brain and plasma concentrations were measured to assess brain-to-plasma ratios. A porcine AF model was used to estimate the antiarrhythmic potential. Electrophysiological properties were evaluated, using two-electrode voltage clamp experiment on Xenopus laevis oocytes which heterologously expressed atrial potassium channels, to calculate the effect of doxapram and ketodoxapram on channel function. Furthermore, whole-cell patch clamp measurements were performed on isolated human cardiomyocytes.

Results

Doxapram and ketodoxapram showed strong inhibitory effects on TASK-1 (IC50 1.0 μM and 0.8 μM) and TASK-3 (5.9 μM and 1.5 μM), but no significant effect on the other measured ion channels. The maximal inhibition on TASK-1 was 96%. The brain-to-plasma ratio for doxapram (0.58) was almost ten-fold higher than for ketodoxapram (0.065), hinting at a reduced crossing of the blood-brain barrier (BBB) for ketodoxapram. The terminal half-life (t1/2) of ketodoxapram (1.71 h) was longer and the maximal concentration (Cmax; 4,604 ng/ml) was higher than for doxapram (1.38 h; 1,780 ng/ml). In a porcine model of AF, ketodoxapram led to a significantly reduced AF burdens comparable to doxapram.

Conclusions

Doxapram and ketodoxapram both show strong inhibitory effects on TASK-1, making them good candidates for a TASK-1 based AF therapy. Ketodoxapram with its longer t1/2, reduced crossing of the BBB and higher Cmax points towards a possible superiority in the treatment of AF compared to doxapram. Studies in a porcine AF model showed promising results for the use of doxapram and ketodoxapram in AF therapy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation

Measurement of Lepton-Jet Correlation in Deep-Inelastic Scattering with the H1 Detector Using Machine Learning for Unfolding

The first measurement of lepton-jet momentum imbalance and azimuthal correlation in lepton-proton scattering at high momentum transfer is presented. These data, taken with the H1 detector at HERA, are corrected for detector effects using an unbinned machine learning algorithm (multifold), which considers eight observables simultaneously in this first application. The unfolded cross sections are compared with calculations performed within the context of collinear or transverse-momentum-dependent factorization in quantum chromodynamics as well as Monte Carlo event generators.

Targeting Cell-Specific Molecular Mechanisms of Innate Immunity in Atherosclerosis

Mechanisms of innate immunity contribute to inflammation, one of the major underlying causes of atherogenesis and progression of atherosclerotic vessel disease. How immune cells exactly contribute to atherosclerosis and interact with molecules of cholesterol homeostasis is still a matter of intense research. Recent evidence has proposed a potential role of previously underappreciated cell types in this chronic disease including platelets and dendritic cells (DCs). The pathophysiology of atherosclerosis is studied in models with dysfunctional lipid homeostasis and several druggable molecular targets are derived from these models. Specific therapeutic approaches focussing on these immune mechanisms, however, have not been successfully introduced into everyday clinical practice, yet. This review highlights molecular insights into immune processes related to atherosclerosis and potential future translational approaches targeting these molecular mechanisms.

[Emergency room activation due to trauma mechanism]

BACKGROUND

The quality of trauma care in Germany has been significantly increased due to the establishment of standards in the white paper on severe injury care and the S3 guidelines. A key issue of multiple trauma treatment is the trauma resuscitation unit (TRU)/emergency room management, which is associated with extensive material and human resources. From the very beginning of the introduction of structured care for the severely injured, the choice of the target hospital and the indications for TRU have been the focus of scientific research. Furthermore, a reduction of the TRU team for presumably less seriously injured patients is discussed.

MATERIAL AND METHODS

The emergency room assignments of a level I trauma center (n = 686) were analyzed in more detail. Of the patients 235 were assigned with the TRU indications according to the cause of the accident (GoR B criteria) and compared with the collective of TRU patients admitted according to the severity of injuries or life-threatening signs, the so-called GoR A criteria (n = 104) during the corresponding period. In addition to basic data (age, sex), the injured region and severity (injury severity score, ISS), the length of stay in the intensive care unit (ICU) and hospital as well as the necessity for surgery and transfusion were compared.

RESULT

Of the emergency room allocations at the trauma center 34% were due to the cause of the accident and the severity of the injuries in this patient group was almost half as high as that of the control group with an ISS of 11. Of the patients 74% were admitted to the IMC/ICU and stayed there for an average of almost 3 days. There were between 4% and 18% severe injuries (abbreviated injury scale, AIS 3) and 17.9% were characterized as polytrauma with an ISS ≥ 16 points.

CONCLUSION

A significant number of patients admitted to a TCU due to the cause of accident (the so-called B criteria of the white book), have severe and potentially life-threatening injuries, which necessitate a prioritized and immediate treatment by a TCU team. Whether a reduced TCU team is sufficient in this situation needs to be critically examined.

Coating of PLA-nanoparticles with cyclic, arginine-rich cell penetrating peptides enables oral delivery of liraglutide

Until today, the oral delivery of peptide drugs is hampered due to their instability in the gastrointestinal tract and low mucosal penetration. To overcome these hurdles, PLA (polylactide acid)-nanoparticles were coated with a cyclic, polyarginine-rich, cell penetrating peptide (cyclic R9-CPP). These surface-modified nanoparticles showed a size and polydispersity index comparable to standard PLA-nanoparticles. The zeta potential showed a significant increase indicating successful CPP-coupling to the surface of the nanoparticles. Cryo-EM micrographs confirmed the appropriate size and morphology of the modified nanoparticles. A high encapsulation efficiency of liraglutide could be achieved. In vitro tests using Caco-2 cells showed high viability indicating the tolerability of this novel formulation. A strongly enhanced mucosal binding and penetration was demonstrated by a Caco-2 binding and uptake assay. In Wistar rats, the novel nanoparticles showed a substantial, 4.5-fold increase in the oral bioavailability of liraglutide revealing great potential for the oral delivery of peptide drugs.

Hypoxia and the group VII ethylene response transcription factor HRE2 promote adventitious root elongation in Arabidopsis

Soil water-logging and flooding are common environmental stress conditions that can impair plant fitness. Roots are the first organs to be confronted with reduced oxygen tension as a result of flooding. While anatomical and morphological adaptations of roots are extensively studied, the root system architecture is only now becoming a focus of flooding research. Adventitious root (AR) formation shifts the root system higher up the plant, thereby facilitating supply with oxygen, and thus improving root and plant survival. We used Arabidopsis knockout mutants and overexpressors of ERFVII transcription factors to study their role in AR formation under hypoxic conditions and in response to ethylene. Results show that ethylene inhibits AR formation. Hypoxia mainly promotes AR elongation rather than formation mediated by ERFVII transcription factors, as indicated by reduced AR elongation in erfVII seedlings. Overexpression of HRE2 induces AR elongation to the same degree as hypoxia, while ethylene overrides HRE2-induced AR elongation. The ERFVII transcription factors promote establishment of an AR system that is under negative control by ethylene. Inhibition of growth of the main root system and promotion of AR elongation under hypoxia strengthens the root system in upper soil layers where oxygen shortage may last for shorter time periods.

Determination of the strong coupling constant α s ( m Z ) in next-to-next-to-leading order QCD using H1 jet cross section measurements: H1 Collaboration

The strong coupling constant α s is determined from inclusive jet and dijet cross sections in neutral-current deep-inelastic ep scattering (DIS) measured at HERA by the H1 collaboration using next-to-next-to-leading order (NNLO) QCD predictions. The dependence of the NNLO predictions and of the resulting value ofα s ( m Z ) at the Z-boson mass m Z are studied as a function of the choice of the renormalisation and factorisation scales. Using inclusive jet and dijet data together, the strong coupling constant is determined to beα s ( m Z ) = 0.1157 ( 20 ) exp ( 29 ) th . Complementary,α s ( m Z ) is determined together with parton distribution functions of the proton (PDFs) from jet and inclusive DIS data measured by the H1 experiment. The valueα s ( m Z ) = 0.1142 ( 28 ) tot obtained is consistent with the determination from jet data alone. The impact of the jet data on the PDFs is studied. The running of the strong coupling is tested at different values of the renormalisation scale and the results are found to be in agreement with expectations.

[Therapy refractory stromal Herpes keratitis under aciclovir]

We report the case of a patient with suspected ulcerating necrotizing herpetic stromal keratitis who showed no improvement despite intensive (amongst others antiherpetic) topical and systemic therapy. The ulcer healed following amniotic membrane transplantation and penetrating excimer laser keratoplasty was performed to improve visual acuity. The excision showed deep stromal proof of herpes simplex virus (HSV) type 1 antigens.

Inter-observer agreement for diagnostic classification of esophageal motility disorders defined in high-resolution manometry

High-resolution esophageal manometry (HRM) is a recent development used in the evaluation of esophageal function. Our aim was to assess the inter-observer agreement for diagnosis of esophageal motility disorders using this technology. Practitioners registered on the HRM Working Group website were invited to review and classify (i) 147 individual water swallows and (ii) 40 diagnostic studies comprising 10 swallows using a drop-down menu that followed the Chicago Classification system. Data were presented using a standardized format with pressure contours without a summary of HRM metrics. The sequence of swallows was fixed for each user but randomized between users to avoid sequence bias. Participants were blinded to other entries. (i) Individual swallows were assessed by 18 practitioners (13 institutions). Consensus agreement (≤ 2/18 dissenters) was present for most cases of normal peristalsis and achalasia but not for cases of peristaltic dysmotility. (ii) Diagnostic studies were assessed by 36 practitioners (28 institutions). Overall inter-observer agreement was 'moderate' (kappa 0.51) being 'substantial' (kappa > 0.7) for achalasia type I/II and no lower than 'fair-moderate' (kappa >0.34) for any diagnosis. Overall agreement was somewhat higher among those that had performed >400 studies (n = 9; kappa 0.55) and 'substantial' among experts involved in development of the Chicago Classification system (n = 4; kappa 0.66). This prospective, randomized, and blinded study reports an acceptable level of inter-observer agreement for HRM diagnoses across the full spectrum of esophageal motility disorders for a large group of clinicians working in a range of medical institutions. Suboptimal agreement for diagnosis of peristaltic motility disorders highlights contribution of objective HRM metrics.

[Nephrotic syndrome in a woman with tuberous sclerosis]

HISTORY AND CLINICAL FINDINGS

A 50-year-old woman with known tuberous sclerosis complex (TSC) was referred for further work-up of nephrotic syndrome. A left-side nephrectomy due to an anamnestically reported "shrunken kidney" had been performed at the age of 15 years. The patient presented with massive edematous swelling of all extremities and typical cutaneous lesions of TSC. DIAGNOSTIC FINDINGS, TREATMENT AND CLINICAL COURSE: Laboratory analysis revealed nephrotic proteinuria, hypalbuminemia and advanced impairment of kidney function. Computed tomography revealed a massively enlarged remaining kidney with confluent angiomyolipomata. As kidney biopsy was deemed to be too hazardous, a thorough work-up for potentially underlying diseases finally revealed endometrial carcinoma. Hysterectomy resulted in a prompt and sustained decrease of proteinuria and disappearance of edema.

CONCLUSION

Although a renal involvement is typical in TSC the occurrence of nephrotic syndrome is not and should give reason for further evaluation.

Toward more accurate measurements of anorectal motor and sensory function in routine clinical practice: validation of high-resolution anorectal manometry and Rapid Barostat Bag measurements of rectal function

BACKGROUND

Measurements of anorectal function using high-resolution anorectal manometry (HR-ARM) and rectal barostat technology provide more reliable results than standard ARM with an elastic balloon; however, HR-ARM results have not been compared to ARM and standard barostat protocols are impractical in routine clinical practice. The aim of this study was to validate HR-ARM against standard ARM and standard barostat against a novel Rapid Barostat Bag (RBB) measurement and elastic balloon measurements of rectal function.

METHODS

Twenty-six healthy volunteers (15 female, 11 male, 19-52 years) were studied. Measurements of anal function and simulated defecation were compared for 12-sensor HR-ARM and 6-sensor standard ARM using line plots from the same recording. Rectal capacity, compliance, and sensation (volume threshold) were measured by elastic balloon, standard barostat, and RBB methods using stepwise inflation of a 700-mL polyethylene bag to 40 mmHg distension by electronic barostat and handheld syringe monitored by sphygmo-manometer, respectively. Results are reported as mean ± SD. Bland-Altman plots and correlation coefficients (r) for measurements were calculated.

KEY RESULTS

There was excellent agreement between HR- and standard ARM measurements (r > 0.86, <25 mmHg difference) and between standard barostat and RBB measurements of rectal capacity (r = 0.97, <25 mL difference). Correlation coefficients of threshold volumes for initial perception, urgency and discomfort were 0.37, 0.71, and 0.95, respectively. No significant correlation was present with elastic balloon measurements. Time to complete studies was shorter for HR-ARM than standard ARM and for RBB than standard barostat in historical controls.

CONCLUSIONS & INFERENCES

HR-ARM with RBB measurements of anorectal function provides quick and reasonably accurate measurements of continence function suitable for use in routine clinical practice (ClinicalTrial.gov NCT01456442).

The effect of standard compared to enhanced instruction and verbal feedback on anorectal manometry measurements

BACKGROUND

Guidelines recommend instruction and motivation during anorectal manometry; however, its impact on findings has not been reported. This study assessed the effects of standard versus enhanced instruction and verbal feedback on the results of anorectal manometry.

METHODS

High-resolution manometry was performed by a solid-state catheter with 10 circumferential sensors at 6 mm separation across the anal canal and two rectal sensors. Measurements were acquired first with standard instruction and then with enhanced instruction and verbal feedback. On both occasions, squeeze pressure and duration during three voluntary contractions and intra-rectal pressure and recto-anal pressure gradient (RAPG) during three attempts at simulated defecation were assessed.

KEY RESULTS

A total of 70 consecutive patients (54 female; age 25-82 years) referred for investigation of fecal incontinence (n = 31), constipation, and related disorders of defecation (n = 39) were studied. Enhanced instruction and verbal feedback increased maximum squeeze pressure (Δ10 ± 28.5 mmHg; P < 0.0038) and duration of contraction (Δ3 ± 4 s; P < 0.0001). During simulated defecation, it increased intra-rectal pressure (Δ12 ± 14 mmHg; P < 0.003) and RAPG (Δ11 ± 20 mmHg; P < 0.0001). Using standard diagnostic criteria, the intervention changed manometric findings from locally validated 'pathologic' to 'normal' values in 14/31 patients with incontinence and 12/39 with disorders of defecation.

CONCLUSIONS & INFERENCES

Enhanced instruction and verbal feedback significantly improved voluntary anorectal functions and resulted in a clinically relevant change of manometric diagnosis in some patients. Effective explanation of procedures and motivation during manometry is required to ensure consistent results and to provide an accurate representation of patient ability to retain continence and evacuate stool.

Measuring the interaction of meal and gastric secretion: a combined quantitative magnetic resonance imaging and pharmacokinetic modeling approach

BACKGROUND

The stimulation and intragastric accumulation of gastric secretion has been recognized as an important factor in gastroesophageal reflux disease. However, the interaction of gastric secretion and meal emptying has not been fully understood. Current methods to assess gastric secretion are either invasive or unable to provide information on its volume, distribution and dynamics. The aim of this study was to quantify the interaction between meal emptying and meal induced gastric secretion by using quantitative magnetic resonance imaging (MRI) and pharmacokinetic analysis.

METHODS

A chocolate test meal was developed which is secretion stimulating and MRI compatible. Meal emptying and gastric secretion were assessed in fourteen healthy volunteers using a validated quantitative MRI technique. A population based pharmacokinetic model was developed and applied to the extracted volume data, assessing the meal emptying rate, rate of secretion and their interaction.

KEY RESULTS

The test meal continuously induced gastric secretion in all subjects, which partly accumulated at the meal-air interface, forming a 'secretion layer' in the proximal stomach. Traditional fitting detected a significant correlation between meal emptying rate and rate of secretion. The pharmacokinetic model quantified this interaction and estimated a 2.3 ± 1 fold higher effect of meal on secretion than vice versa. The efficacy of the emptied meal to produce gastric secretion was 61%.

CONCLUSIONS & INFERENCES

The combined quantitative MRI and pharmacokinetic model approach allows for the quantification of gastric secretion volume and its interaction on meal emptying. The observed secretion layer might explain previous findings postulating the presence of an intragastric 'acid pocket'.

Exploring the influence of operational parameters on the reactivity of elemental iron materials

In an attempt to characterize material intrinsic reactivity, iron dissolution from elemental iron materials (Fe(0)) was investigated under various experimental conditions in batch tests. Dissolution experiments were performed in a dilute solution of ethylenediaminetetraacetate (Na(2)-EDTA - 2mM). The dissolution kinetics of 18 Fe(0) materials were investigated. The effects of individual operational parameters were assessed using selected materials. The effects of available reactive sites [Fe(0) particle size (<or=2.0mm) and metal loading (2-64 g L(-1))], mixing type (air bubbling, shaking), shaking intensity (0-250 min(-1)), and Fe(0) pre-treatment (ascorbate, HCl and EDTA washing) were investigated. The data were analysed using the initial dissolution rate (k(EDTA)). The results show increased iron dissolution with increasing reactive sites (decreasing particle size or increasing metal loading), and increasing mixing speed. Air bubbling and material pre-treatment also lead to increased iron dissolution. The main output of this work is that available results are hardly comparable as they were achieved under very different experimental conditions. A unified experimental procedure for the investigation of processes in Fe(0)/H(2)O systems is suitable. Alternatively, a parameter (tau(EDTA)) is introduced which could routinely used to characterize Fe(0) reactivity under given experimental conditions.

Evaluation of the effects of shaking intensity on the process of methylene blue discoloration by metallic iron

The term mixing (shaking, stirring, agitating) is confusing because it is used to describe mass transfer in systems involving species dissolution, species dispersion and particle suspension. Each of these mechanisms requires different flow characteristics in order to take place with maximum efficiency. This work was performed to characterize the effects of shaking intensity on the process of aqueous discoloration of methylene blue (MB) by metallic iron (Fe(0)). The extent of MB discoloration by three different materials in five different systems and under shaking intensities varying from 0 to 300 min(-1) was directly compared. Investigated materials were scrap iron (Fe(0)), granular activated carbon (GAC), and deep sea manganese nodules (MnO(2)). The experiments were performed in essay tubes containing 22 mL of the MB solution (12 mg/L or 0.037 mM). The essay tubes contained either: (i) no reactive material (blank), (ii) 0-9.0 g/L of each reactive material (systems I, II and III), or (iii) 5g/L Fe(0) and 0 to 9.0g/L GAC or MnO(2) (systems IV and V). The essay tubes were immobilized on a support frame and shaken for 0.8-5 days. Non-shaken experiments lasted for duration up to 50 days. Results show increased MB discoloration with increasing shaking intensities below 50 min(-1), a plateau between 50 and 150 min(-1), and a sharp increase of MB discoloration at shaking intensities >or=200 min(-1). At 300 min(-1), increased MB discoloration was visibly accompanied by suspension of dissolution products of Fe(0)/MnO(2) and suspension of GAC fines. The results suggest that, shaking intensities aiming at facilitating contaminant mass transfer to the Fe(0) surface should not exceed 50 min(-1).

Endogenous retroviruses and cancer

The genomes of vertebrates contain sequences that are similar to present-day exogenous retroviruses. Such sequences, called endogenous retroviruses (ERVs), have resulted from ancestral germ line infections by exogenous retroviruses which have thereafter been transmitted in a Mendelian fashion. By analogy to exogenous tumorigenic retroviruses, ERVs have been implicated in the pathogenesis of cancer. Cumulative evidence from animal models indicates that ERVs may participate in the process of malignant transformation or promote tumor growth, e.g. through insertional mutagenesis or via counteracting tumor immunosurveillance. Here, we review the role of ERVs in tumorigenesis with focus on human ERVs (HERVs) in human cancer. Although available data suggest a potential role of HERVs in human cancers, in particular germ cell tumors, the contributions of HERVs to human tumorigenesis warrant further elucidation. (Part of a multi-author review).

Efficacy, safety and tolerability of rivastigmine capsules in patients with probable vascular dementia: the VantagE study

OBJECTIVE

The aim was to evaluate the efficacy, safety and tolerability of rivastigmine capsules in patients diagnosed with probable vascular dementia (VaD).

METHODS

VantagE (Vascular Dementia trial studying Exelon) was a 24-week, multicentre, double-blind study. VaD patients aged 50-85 years were randomized to rivastigmine capsules (3-12 mg/day) or placebo. Efficacy assessments included global and cognitive performances, activities of daily living and neuropsychiatric symptoms. Adverse events were recorded. Additional exploratory analyses determined whether heterogeneity in pathologies and symptoms extended to differential treatment effects.

TRIAL REGISTRATION

NCT00099216.

RESULTS

710 patients were randomized. Rivastigmine demonstrated superiority over placebo on three measures of cognitive performance (Vascular Dementia Assessment Scale, Alzheimer's Disease Assessment Scale cognitive subscale, Mini-Mental State Examination; all p< or = 0.05, intent-to-treat population [ITT]), but not other outcomes. Predominant adverse events were nausea and vomiting. Exploratory analyses indicated that older patients (> or =75 years old), assumed more likely to also have Alzheimer's disease (AD) pathology, demonstrated significant cognitive responses to rivastigmine and a safety profile similar to that seen in AD patients. Younger patients, assumed less likely to have concomitant AD pathology, showed no efficacy response and were associated with slight elevations of blood pressure, cerebrovascular accidents and mortality. Rivastigmine-placebo differences in patients with, versus those without, medial temporal atrophy (also suggestive of concomitant AD) showed a numerical difference similar to that seen between the older versus younger patients, but did not attain statistical significance.

CONCLUSION

Consistent with trials evaluating other cholinesterase inhibitors, rivastigmine did not provide consistent efficacy in probable VaD. The efficacy apparent on cognitive outcomes was derived from effects in older patients likely to have concomitant Alzheimer pathology. This is supportive of an existing argument that the putative cholinergic deficit in VaD reflects the presence of concomitant Alzheimer pathology.

Comet assay analysis of single-stranded DNA breaks in circulating leukocytes of glaucoma patients

PURPOSE

To investigate the amount of single-stranded DNA breaks in circulating leukocytes of primary open-angle glaucoma (POAG) patients.

METHODS

A comparative quantification of DNA breaks was performed in circulating leukocytes of POAG patients and healthy controls. The following groups of subjects were compared: (1) POAG patients having primary vascular dysregulation (PVD), (2) POAG patients without PVD, (3) healthy controls with PVD, and (4) healthy controls without PVD. The damage to DNA resulting in single-stranded breaks was assessed by means of the alkaline comet assay in which the damaged DNA migrates out of the nucleus forming a tail, which can be quantified using image analysis. Damage was quantified as the comet tail moment, which represents the extent of DNA damage in individual cells.

RESULTS

Leukocytes of POAG patients exerted a significantly higher amount of comet tails, which are indicative of DNA damage, in comparison to control leukocytes (p<0.001). DNA breaks occurred particularly in the subgroup of POAG patients with PVD in comparison to glaucoma patients without PVD (p=0.002). In the control group, there was no significant difference between controls with PVD and controls without PVD (p=0.86).

CONCLUSIONS

POAG patients with PVD have a significantly higher rate of DNA breaks than both POAG patients without PVD and healthy controls with and without PVD.

Lupus nephritis

Lupus nephritis is a common complication of systemic lupus erythematosus (SLE). Early recognition of lupus nephritis requires routine serum creatinine determination, urinalysis and urinary microscopy. Since mild urinary abnormalities such as leucocyturia or proteinuria can be associated with severe lupus nephritis, a renal biopsy is usually indicated in patients with SLE and urinary abnormalities. A renal biopsy is required to determine the class of lupus nephritis which is based on histopathological criteria which have recently been revised. Aggressive immunosuppressive therapy is indicated in diffuse proliferative lupus nephritis. In class III or class V the treatment indication depends on additional prognostic criteria. Intravenous cyclophosphamide is still used but doses and intervals have been modified based on large clinical trials. Mycopheno-late may establish as an alternative for cyclophosphamide in the induction phase, but the data of the transcontinental multicenter Aspreva Lupus Management Study (ALMS) trial have not yet been published in detail. Controlled clinical trials support the use of azathioprine and mycophenolate for maintaining remission of lupus nephritis, and cyclophosphamide is no longer used in that phase. Additional control of cardiovascular risk factors and combined angiotensin and angiotensin receptor blockade are mandatory for all proteinuric SLE patients. Novel treatment options are ahead of us based on the molecular mechanisms of SLE and lupus nephritis, but as evidence from controlled clincial trials is still lacking they are not yet approved for broad clinical use. However, the treatment options for severe lupus nephritis have been improved and are likely to further improve in the near future.

Up-regulation of the human serum and glucocorticoid-dependent kinase 1 in glomerulonephritis

Glomerulonephritis is paralleled by excessive formation of transforming growth factor-beta (TGF-beta), which participates in the pathophysiology of the disease. Recently, a novel downstream target of TGF-beta has been identified, i.e. the human serum and glucocorticoid-dependent kinase 1 (hSGK1), a serine/threonine kinase participating in the regulation of Na(+) transport. The present study was performed to elucidate transcriptional regulation of hSGK1 in glomerulonephritis. To this end, in situ hybridization was performed in biopsies from patients with clinical diagnosis of glomerulonephritis. hSGK1 transcript levels were moderately enhanced in 5 out of 9 patients and strongly enhanced in 4 out of 9 patients. Distal nephron epithelial cell hSGK1 transcript levels were low or absent in 7 of the 9 patients but markedly enhanced in 2 of the 9 patients. In conclusion, glomerulonephritis leads to glomerular and in some cases to epithelial up-regulation of hSGK1 transcription.

Use of Short Chained Alkylphenols (SCAP) in Analysis of Transport Behaviour of Oil Contaminated Groundwater

Shortchained alkylphenols (SCAP) represent a main constituent of crude oil and coal liquefaction products. Due to their specific oil/water partitioning behaviour and high aqueous solubility they can be detected in oil exploitation waters and groundwaters affected by various spills near oil pipelines, oil exploitation sites and coal liquefaction plants. New efficient and powerful analytical techniques have been developed that allow the identification of all 34 individual compounds (C0-C3) without derivatisation and in complex matrices. Due to the different physico-chemical properties of the SCAP, differential transport behaviour in groundwater can be observed, changing the relative concentrations of SCAP downgradient in space and time. These characteristic ratios can be employed to derive information on migration direction and the ageing of the source of contamination. A case study is presented to illustrate the use of this new tool. 

Assessments of the sensitivity to climate change of flow and natural water quality in four major carbonate aquifers of Europe

A numerical modelling approach has been developed to predict the vulnerability of aquifers to future climate change. This approach encompasses changes in recharge regime, dynamics of flow and storage patterns within aquifers, and natural hydrochemical changes. An application of the approach has been made to four hypothetical spring catchments representative of major carbonate aquifers in three European climatic zones. Since prolific carbonate aquifers typically combine a high transmissivity with a low specific yield, they can be expected to be more sensitive than clastic aquifers to changes in recharge patterns. Simulations of the study systems to the middle of the 21st century predict different outcomes in the three different climate zones: (1) in the northern maritime zone (UK) recharge (and therefore discharge) is predicted to increase by as much as 21 0n response to anticipated increases in precipitation; (2) in the continental zone (Germany) recharge in winter is predicted to remain approximately the same as at present, but summer recharge will decline dramatically (by as much as 32%), so that a net decrease in aquifer discharge is predicted; and (3) in the Mediterranean zone (Spain) recharge is predicted to decrease by as much as 160f the present-day values. For all three systems, increases in water hardness in response to rising CO2 are predicted, but are expected to be negligible in water resources terms.

HERV-K(OLD): ancestor sequences of the human endogenous retrovirus family HERV-K(HML-2)

Sequences homologous to the human endogenous retrovirus (HERV) family HERV-K(HML-2) are present in all Old World primate species. A previous study showed that a central region of the HERV-K(HML-2) gag genes in Hominoidea species displays a 96-bp deletion compared to the gag genes in lower Old World primates. The more ancient HERV-K(HML-2) sequences present in lower Old World primates were apparently not conserved during hominoid evolution, as opposed to the deletion variants. To further clarify the evolutionary origin of the HERV-K(HML-2) family, we screened GenBank with the 96-bp gag-sequence characteristic of lower Old World primates and identified, to date, 10 human sequence entries harboring either full-length or partially deleted proviral structures, probably representing remnants of a more ancient HERV-K(HML-2) variant. The high degree of mutations demonstrates the long-time presence of these HERV-K(OLD) proviruses in the genome. Nevertheless, they still belong to the HML-2 family as deduced from dot matrix and phylogenetic analyses. We estimate, based on the family ages of integrated Alu elements and on long terminal repeat (LTR) divergence data, that the average age of HERV-K(OLD) proviruses is ca. 28 million years, supporting an integration time before the evolutionary split of Hominoidea from lower Old World primates. Analysis of HERV-K(OLD) LTR sequences led to the distinction of two subgroups, both of which cluster with LTRs belonging to an evolutionarily older cluster. Taken together, our data give further insight into the evolutionary history of the HERV-K(HML-2) family during primate evolution.

The Rev/Rex homolog HERV-K cORF multimerizes via a C-terminal domain

Expression of human endogenous retrovirus K (HERV-K) is associated with germ-cell neoplasia. HERV-K encodes a protein of the Rev/Rex family, cORF, that supports cellular transformation and binds the promyelocytic leukemia zinc finger (PLZF) protein implicated in spermatogenesis. Rev/Rex function invariably depends on multimerization. Here we show that cORF likewise self-associates to form higher-order oligomers. Amino acids (aa) 47-87 in cORF are sufficient, aa 75-87 essential for self-association. Consistently, this domain is predicted to form a hydrophobic alpha-helix that may represent an oligomerization interface. The existence of a dimerization-competent cORF mutant lacking PLZF-binding activity (cORF47-87) suggests a way of dominant negative inhibition of the proposed tumor susceptibility factor cORF.

Genomic organization of the human endogenous retrovirus HERV-K(HML-2.HOM) (ERVK6) on chromosome 7

Recently, we reported an almost intact human endogenous retrovirus (HERV-K(HML-2.HOM); HGMW-approved symbol ERVK6) located on human chromosome 7, with open reading frames for all retroviral genes and a mutation only within the reverse transcriptase. We further characterized the genomic organization of this endogenous retrovirus by subcloning and sequencing of the proviral insert contained within a chromosome 7-specific cosmid clone and found HERV-K(HML-2.HOM) to be organized as a tandem repeat. Examination of various human DNA samples for this specific proviral repeat suggests a relatively ubiquitous distribution of the HERV-K(HML-2.HOM) tandem structure. However, we identified two human samples having only a single provirus at this locus. In addition, we investigated the presence of HERV-K(HML-2.HOM) alleles having an intact YXDD motif within the reverse transcriptase domain by sequencing the corresponding polymerase gene from various human DNA samples. We identified a HERV-K(HML-2.HOM) polymerase with an intact YXDD motif in two samples, thus potentially coding for an active reverse transcriptase. Our results show for the first time an endogenous retrovirus tandem repeat in human populations and suggest the existence of alleles harboring an intact human endogenous retrovirus including an intact polymerase gene.

Expression of cell volume-regulated kinase h-sgk in pancreatic tissue

Transcript levels of the human serine/threonine kinase h-sgk have been found to be highest in pancreas. In the present study, localization and regulation of h-sgk transcription in pancreatic tissue were elucidated. As was apparent from radioactive in situ hybridization, most pancreatic acinar cells expressed high levels of h-sgk mRNA. h-sgk mRNA-positive cells were also found in ductal epithelia but not in pancreatic islets. In biopsy specimens from patients with pancreatitis, h-sgk mRNA levels were decreased in acinar cells but abundant in numerous mononuclear interstitial cells within areas of pancreatic necrosis and fibrosis. As shown by Northern blotting, h-sgk transcription in DAN-G pancreatic tumor cells is upregulated by osmotic cell shrinkage, serum, phorbol esters (phorbol 12,13-didecanoate), and Ca(2+) ionophore A-23187 and decreased by staurosporine and cAMP. In conclusion, h-sgk transcription is regulated not only by cell volume but also by serum, protein kinase C stimulation, cAMP, and increase of intracellular Ca(2+) activity. The kinase may participate not only in normal function of exocrine pancreas but also in fibrosing pancreatitis.

Ethylene induces epidermal cell death at the site of adventitious root emergence in rice

In deepwater rice (Oryza sativa), adventitious root primordia initiate at the nodes as part of normal development. Emergence of the roots is dependent on flooding of the plant and is mediated by ethylene action. Root growth was preceded by the induced death of epidermal cells of the node external to the tip of the root primordium. Cell death proceeded until the epidermis split open. Through this crack the root eventually emerged. Induced death was confined to nodal epidermal cells covering the tip of the primordia. Our results suggest that this process facilitates adventitious root emergence and prevents injury to the growing root. Cell death was inducible not only by submergence but also by application of 1-aminocyclopropane-1-carboxylic acid, the natural precursor of ethylene and it was suppressed in the presence of 2,5-norbornadiene (bicyclo[2.2.1]hepta-2,5-diene), an inhibitor of ethylene action. Adventitious root growth and epidermal cell death are therefore linked to the ethylene signaling pathway, which is activated in response to low oxygen stress.

Activation of CDK-activating kinase is dependent on interaction with H-type cyclins in plants

cDNAs encoding cyclin H homologs were isolated from poplar (Populus tremula X tremuloides) and rice (Oryza sativa) plants, and were designated Pt;cycH;1 and Os;cycH;1, respectively. The deduced amino-acid sequences showed 40-60% similarity to human cyclin H and Schizosaccharomyces pombe Mcs2, with higher similarity in the cyclin box region. While Pt;cycH;1 and Os;cycH;1 were expressed in all tissues examined, the transcripts accumulated abundantly in dividing cells. Expression of Os;cycH;1 was abundant in the S-phase in partially synchronized suspension cells, and was induced by submergence in internodes of deepwater rice. A yeast two-hybrid assay demonstrated that both Pt;CycH;1 and Os;CycH;1 were able to interact with rice R2 kinase, which is structurally and functionally similar to cyclin-dependent kinase (CDK)-activating kinase (CAK) of vertebrates. Moreover, an in vitro pull-down assay showed that Os;CycH;1 specifically bound to R2 but not to other rice CDKs. When R2 was expressed in budding yeast CAK mutant, the suppression activity in terms of temperature-sensitivity was enhanced by co-expression with Os;cycH;1. Furthermore, in vitro kinase assay indicated that the kinase activities of R2 on CDKs and the carboxy-terminal domain (CTD) of the largest subunit of RNA polymerase II were markedly elevated by binding to Os;CycH;1. Our results suggest that cyclin H is a regulatory subunit of CAK, which positively controls CDK- and CTD-kinase activities in plant cells.

Human endogenous retrovirus protein cORF supports cell transformation and associates with the promyelocytic leukemia zinc finger protein

Human endogenous retrovirus sequences (HERVs) reside in the genomes of primates and humans for several million years. The majority of HERVs is non-coding but a limited set is intact and can express proteins. We have recently identified an almost intact HERV-K(HML-2) provirus on chromosome 7 and have documented that most patients with germ cell tumors (GCTs) display antibodies directed against proteins of HERV-K(HML-2). To address whether these proteins merely represent tumor markers or contribute to neoplastic transformation, we examined the transforming potential of various HERV sequences and studied physical interactions between HERV and cellular proteins by yeast two-hybrid and biochemical assays. cORF, a protein encoded by the C-terminal open reading frame within the env gene, supports tumor growth in nude mice and associates with the promyelocytic leukemia zinc finger protein (PLZF). The interaction domains map between amino acid residues 21 and 87 of cORF, and between residues 245 and 543 of PLZF. PLZF is critical for spermatogenesis in mice. Abnormal spermatogenesis or maturation of gonocytes is thought to predispose humans to the development of germ cell tumors. Thus, cORF of human endogenous retroviruses may contribute to tumor development by interfering with processes during spermatogenesis that involve PLZF.