Tibia segment deformation in response to simulated muscle forces: a cadaveric study with a novel optical segment tracking (OST) approach

OBJECTIVES

A novel optical segment tracking (OST) approach reliant upon motion capturing was previously proposed to assess human tibia segment deformation. The purposes of the present study were to validate the OST approach and assess the contribution of muscular forces to the bone deformation in a well-defined ex vivo human model.

METHODS

A custom-made Lower Extremity Loading Device (LELD) was developed to simulate physiological muscle contractions in six human cadaveric lower extremities. Tibia segment deformation was measured by tracking the relative movement between two marker clusters which were affixed into the proximal and distal tibia, respectively.

RESULTS

Compared to the physiological norms, the simulated muscle forces remained at a low level. When quadriceps muscle was loaded with forces from 198 N to 505 N, posterior bending (0.12°-0.25°) and lateral bending (0.06°-0.21°) of the tibia segment were found. Large tibia bending angles were found when simulating the co-contraction of upper leg muscles and plantar flexors, and of all leg muscles, respectively. The standard deviations of the deformation angles between the repetitions remained at a low level.

CONCLUSIONS

We conclude that the OST approach has the potential to be applied in vivo and quantify muscle-induced bone deformations.

Open resource metagenomics: a model for sharing metagenomic libraries

Both sequence-based and activity-based exploitation of environmental DNA have provided unprecedented access to the genomic content of cultivated and uncultivated microorganisms. Although researchers deposit microbial strains in culture collections and DNA sequences in databases, activity-based metagenomic studies typically only publish sequences from the hits retrieved from specific screens. Physical metagenomic libraries, conceptually similar to entire sequence datasets, are usually not straightforward to obtain by interested parties subsequent to publication. In order to facilitate unrestricted distribution of metagenomic libraries, we propose the adoption of open resource metagenomics, in line with the trend towards open access publishing, and similar to culture- and mutant-strain collections that have been the backbone of traditional microbiology and microbial genetics. The concept of open resource metagenomics includes preparation of physical DNA libraries, preferably in versatile vectors that facilitate screening in a diversity of host organisms, and pooling of clones so that single aliquots containing complete libraries can be easily distributed upon request. Database deposition of associated metadata and sequence data for each library provides researchers with information to select the most appropriate libraries for further research projects. As a starting point, we have established the Canadian MetaMicroBiome Library (CM(2)BL [1]). The CM(2)BL is a publicly accessible collection of cosmid libraries containing environmental DNA from soils collected from across Canada, spanning multiple biomes. The libraries were constructed such that the cloned DNA can be easily transferred to Gateway® compliant vectors, facilitating functional screening in virtually any surrogate microbial host for which there are available plasmid vectors. The libraries, which we are placing in the public domain, will be distributed upon request without restriction to members of both the academic research community and industry. This article invites the scientific community to adopt this philosophy of open resource metagenomics to extend the utility of functional metagenomics beyond initial publication, circumventing the need to start from scratch with each new research project.

Long-term outcome of patients with argininosuccinate lyase deficiency diagnosed by newborn screening in Austria

Twenty-three patients with late onset argininosuccinate lyase deficiency (ASLD) were identified during a 27-year period of newborn screening in Austria (1:95,600, 95% CI=1:68,036-1:162,531). One additional patient was identified outside the newborn screening with neonatal hyperammonemia. Long-term outcome data were available in 17 patients (median age 13 years) ascertained by newborn screening. Patients were treated with protein restricted diet and oral arginine supplementation during infancy and childhood. IQ was average/above average in 11 (65%), low average in 5 (29%), and in the mild intellectual disability range in 1 (6%) patients. Four patients had an abnormal EEG without evidence of clinical seizures and three had abnormal liver function tests and/or evidence of hepatic steatosis. Plasma citrulline levels were elevated in four patients. Plasma ammonia levels were within normal range prior and after a protein load in all patients. Seven different mutations were identified in the 16 alleles investigated. Four mutations were novel (p.E189G, p.R168C, p.R126P, and p.D423H). All mutations were associated with low argininosuccinate lyase activities (0-15%) in red blood cells. Newborn screening might be beneficial in the prevention of chronic neurologic and intellectual sequelae in late onset ASLD, but a proportion of benign variants might have contributed to the overall favorable outcome as well.

In vitro to in vivo comparison of the substrate characteristics of sorafenib tosylate toward P-glycoprotein

Sorafenib (Nexavar) is a novel oral Raf kinase and vascular endothelial growth factor receptor inhibitor. Most anticancer drugs are substrates for ATP-binding cassette efflux pumps especially for P-glycoprotein (P-gp). To evaluate the influence of P-gp on the pharmacokinetics of sorafenib substrate properties for this transporter were investigated. Therefore, permeability of sorafenib across Caco-2 and P-gp-overexpressing cells was determined. To determine the in vivo relevance of these in vitro findings, pharmacokinetics of sorafenib in mdr1a/1b(-/-) and wild-type (WT) mice was studied. Sorafenib is highly permeable and exhibits a slight efflux across Caco-2 cells. In P-gp-overexpressing cells, a small concentration-dependent efflux was observed, which was completely blocked by the addition of ivermectin. In mdr1a/1b(-/-) and WT mice, unchanged compound represented by far the majority of radioactivity in plasma. After intravenous and oral administration, brain/plasma concentration ratios in mdr1a/1b(-/-) mice were 1.3- to 1.5-fold higher than those in WT mice. However, after intravenous or oral administration, plasma concentrations were similar in both mouse strains. In conclusion, sorafenib is highly permeable and a weak P-gp substrate in vitro. These findings were confirmed by the small factor of 1.3 to 1.5 observed for the brain/plasma ratios in mdr1a/1b(-/-) versus WT mice in vivo. Based on these in vitro and in vivo results, it is unlikely that P-gp has a major effect on the plasma concentrations of sorafenib in humans. Because of the high permeability and low P-gp-mediated transport, sorafenib might be able to cross the blood-brain barrier and target tumors within the brain.

Highly variable clinical phenotype of carbamylphosphate synthetase 1 deficiency in one family: an effect of allelic variation in gene expression?

Deficiency of the urea cycle enzyme carbamylphosphate synthetase 1 (CPS1) causes hyperammonemia with a vast range of clinical severity from neonatal onset with early lethality to onset after age 40 with rare episodes of hyperammonemic confusion. The cause for this variability is not understood. We report two patients from one family with highly divergent clinical course, one presenting neonatally with a fatal form and the other at age 45 with benign diet-responsive disease. The patients are compound heterozygous for two mutations of the CPS1 gene, c.3558 + 1G > C and c.4101 + 2T > C. The haplotypes containing each mutation are identical between the two patients, as are the sequences of CPS1 exons and flanking introns. Transcriptional experiments show that the abnormal CPS1 transcripts generated by both mutations are identical in these two patients. We characterize promoter and enhancer sequences of the CPS1 gene and find also in these regions no sequence differences between patients. Finally, we perform cloning experiments and find that in the neonatal-onset case, clones of messenger RNA (mRNA) expressed from the allele carrying the c.4101 + 2T > C mutation are threefold more than clones of mRNA from the allele with the c.3558 + 1G > C mutation, whereas in the adult-onset case the two types of clones are equal, indicating skewed expression towards the c.4101 + 2T > C allele in the neonatal case. Although we are yet to understand the mechanism of this differential expression, our work suggests that allelic imbalance may explain clinical variability in CPS1 deficiency in some families.

Nocturnal urinary cortisol excretion over a randomized controlled trial with paroxetine vs. placebo combined with relaxation training or aerobic exercise in panic disorder

INTRODUCTION

Data on basal hypothalamo-pituitary-adrenomedullary (HPA) function over controlled treatment trials with serotonergic drugs in anxiety disorders are still rare.

METHODS

29 patients with panic disorder participating in a 10 week randomized, controlled trial (paroxetine vs. placebo with exercise or relaxation; N=60) collected urine for cortisol excretion over 3 consecutive nights before start and before termination of the treatment episode. Urinary cortisol was measured by radioimmunoassay. Efficacy measures were the Clinical Global Impression Scale (CGI) and the Panic and Agoraphobia Scale (P&A). 83% were female (p<.05 vs. males). 55% received additional aerobic exercise, and 45% relaxation. 55% received paroxetine treatment, and 45% placebo. Significantly fewer males received placebo treatment (p<.05).

RESULTS

All subjects improved significantly. Cortisol excretion did not differ between treatment groups or at pre-/post measurements. Females showed a significantly higher variability of cortisol excretion compared to males, at pre-(p<.005) and post (p=.015) assessments. Males displayed a trend to lower basal HPA function at end of treatment (p=.08). HPA variability after treatment showed a trend to be higher in the paroxetine (p=.052) -who clinically improved significantly better- compared to the placebo group. No relationship between HPA activity and treatment response or with exercise was detected.

DISCUSSION

HPA function shows significant gender differences, with females having a higher HPA function variability. Future studies on HPA function in treatment trials should address gender and medication effects.

Three-generational alkaptonuria in a non-consanguineous family

OBJECTIVE

Alkaptonuria (AKU) is a rare inborn error of metabolism of aromatic amino acids and considered to be an autosomal recessive trait caused by mutations in the homogentisate 1,2-dioxygenase (HGD) gene. A dominant pattern of inheritance has been reported but was attributed to extended consanguinity in many cases. However, we have observed a non-consanguineous family segregating AKU in a dominant manner over three generations.

RESULTS

All affected individuals presented with typical features of AKU including darkening of the urine, ochronosis, arthropathy, and elevated urinary excretion of homogentisic acid. Sequence analysis of the HGD gene from genomic DNA of two affected individuals, uncle and niece, revealed a heterozygous missense mutation (M368V) in the uncle that was not present in his niece. Microsatellite genotyping demonstrated that both were heterozygous at the HGD locus and shared one haplotype. This haplotype did not contain a detectable HGD mutation. The haplotype was also found in a healthy son of the niece, making a dominant HGD mutation unlikely. Moreover, sequencing of cDNA from lymphoblastoid cells of the niece did not reveal an HGD mRNA with a potentially dominant-negative effect.

CONCLUSION

Rare causes of the uncommon AKU inheritance in this family have to be considered, ranging from the coincidence of undetectable HGD mutations to a dominant mutation of a second, hitherto unknown AKU gene.

[Early detection of anxiety disorders]

Anxiety disorders represent a widespread illness. Those affected with initial symptoms usually seek the help of their family doctor. In many cases, considerable time passes before the diagnosis has been established and specialised treatment applied, with the result that chronification is furthered. Physical symptoms of an anxiety disorder, and fears of contracting somatic disease are almost always the first to be described. In patients abusing alcohol and/or hypnotics consideration must always be given to an anxiety disorder. Previously existing symptoms almost always include depressive moods or avoidance behavior. Stressful life events and other psychosocial stressful factors may also point the way to the early diagnosis of an anxiety disorder.

Penetration of Pollen Proteins into the Skin

Atopic dermatitis is a chronic remittent skin disease. In the extrinsic form of atopic dermatitis, type IgE-mediated reactions play an important pathophysiological role. The aim of the present study was to examine whether type I allergens can penetrate into the skin. Therefore, pollen proteins were labeled with fluorescein isothiocyanate (FITC), and their penetration profile was studied qualitatively. Solutions of FITC-labeled pollen proteins were applied in vitro on porcine skin and in vivo on human skin. In vitro, the FITC-labeled proteins were observed within the complete stratum corneum (SC) and inside the hair follicles even 15 min after application. They were also distributed inside the dermis around the hair follicles. In vivo, a similar pattern of distribution within the SC and the hair follicles was observed. These results indicate penetration via the SC lipid layers and a faster penetration via the hair follicles. The FITC-labeled proteins entered the dermis via the follicular pathway. Therefore, the follicular penetration should be considered in the development of skin protection strategies. To evaluate such strategies, the developed method can be used, and further studies in atopic dermatitis patients are necessary to determine whether the penetration of type I allergens is increased.

Structural and functional evolution of the P2Y(12)-like receptor group

Metabotropic pyrimidine and purine nucleotide receptors (P2Y receptors) belong to the superfamily of G protein-coupled receptors (GPCR). They are distinguishable from adenosine receptors (P1) as they bind adenine and/or uracil nucleotide triphosphates or diphosphates depending on the subtype. Over the past decade, P2Y receptors have been cloned from a variety of tissues and species, and as many as eight functional subtypes have been characterized. Most recently, several members of the P2Y₁₂-like receptor group, which includes the clopidogrel-sensitive ADP receptor P2Y₁₂, have been deorphanized. The P2Y₁₂-like receptor group comprises several structurally related GPCR which, however, display heterogeneous agonist specificity including nucleotides, their derivatives, and lipids. Besides the established function of P2Y₁₂ in platelet activation, expression in macrophages, neuronal and glial cells as well as recent results from functional studies implicate that several members of this group may have specific functions in neurotransmission, inflammation, chemotaxis, and response to tissue injury. This review focuses specifically on the structure-function relation and shortly summarizes some aspects of the physiological relevance of P2Y₁₂-like receptor members.

Usnea barbata extract prevents ultraviolet-B induced prostaglandin E2 synthesis and COX-2 expression in HaCaT keratinocytes

Usnea barbata and its major constituent usnic acid are potent antimicrobial agents. Here, we have investigated anti-inflammatory properties of an U. barbata extract (UBE) containing 4% usnic acid in an ultraviolet-B (UVB) model with HaCaT keratinocytes. UVB irradiation induced PGE(2) production and COX-2 expression in a time and dose-dependent manner. UBE inhibited PGE(2) production at a half-maximal concentration of 60 microg/ml (2.4 microg/ml usnic acid) that did not affect the UVB-induced upregulation of COX-2, suggesting an effect on enzyme activity rather than on protein expression. The inhibition of PGE(2) production by UBE was not due to cytotoxicity. Besides its known antimicrobial properties, UBE displays specific UVB protective effects that might be useful in the topical treatment of UVB-mediated inflammatory skin conditions.

Composition and biological activity of different extracts from Schisandra sphenanthera and Schisandra chinensis

Plants of the Schisandraceae family contain a variety of pharmacologically active lignans like schizandrin, deoxyschizandrin, deangeloylgomisin B, gomisin A, gomisin O, gamma-schizandrin and isogomisin O. Here we have compared the composition of different polar and non-polar extracts of Schisandra sphenanthera and Schisandra chinensis. We also have screened the extracts for antiproliferative and anti-inflammatory effects in different cell-based and cell-free assays. Extracts produced with the non-polar solvents CO(2), hexane and CO(2)/5% ethanol had a similar composition. In contrast, polar extraction with ethanol provided a considerably higher yield, but a lower content of volatiles and lignans in comparison to the non-polar extracts. The proliferation of the epidermal cell lines HaCaT and A431 was dose-dependently inhibited by both the Schisandra sphenanthera and Schisandra chinensis extracts, the non-polar extracts being superior to the polar ones. The non-polar Schisandra sphenanthera extract was the most active with a half-maximal inhibitory concentration of 20 microg/mL. In a cell-free enzyme inhibition assay with recombinant cyclooxygenase-2 (COX-2) the non-polar Schisandra sphenanthera extract dose-dependently inhibited COX-2 catalysed prostaglandin (PG) production (IC(50) = 0.2 microg/mL). It also reduced the ultraviolet-B (UVB)-induced PGE (2) production (IC(50) = 4 microg/mL) and COX-2 expression in HaCaT keratinocytes. We conclude that non-polar SChisandra extracts obtained by CO(2) extraction might be useful in the prevention and treatment of hyperproliferative and inflammatory skin diseases.

Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance

There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema.