Impairment of muscular endothelial cell regeneration in dermatomyositis

Background and aim

Inflammatory myopathies are heterogeneous in terms of etiology, (immuno)pathology, and clinical findings. Endothelial cell injury, as it occurs in DM, is a common feature of numerous inflammatory and non-inflammatory vascular diseases. Vascular regeneration is mediated by both local and blood-derived mechanisms, such as the mobilization and activation of so-called proangiogenic cells (PACs) or early endothelial progenitor cells (eEPCs). The current study aimed to evaluate parameters of eEPC integrity in dermatomyositis (DM), compared to necrotizing myopathy (NM) and to non-myopathic controls.

Methods

Blood samples from DM and NM patients were compared to non-myositis controls and analyzed for the following parameters: circulating CD133⁺/VEGFR-2⁺ cells, number of colony-forming unit endothelial cells (CFU-ECs), concentrations of angiopoietin 1, vascular endothelial growth factor (VEGF), and CXCL-16. Muscle biopsies from DM and NM subjects underwent immunofluorescence analysis for CXCR6, nestin, and CD31 (PECAM-1). Finally, myotubes, derived from healthy donors, were stimulated with serum samples from DM and NM patients, subsequently followed by RT-PCR for the following candidates: IL-1β, IL-6, nestin, and CD31.

Results

Seventeen (17) DM patients, 7 NM patients, and 40 non-myositis controls were included. CD133⁺/VEGFR-2⁺ cells did not differ between the groups. Both DM and NM patients showed lower CFU-ECs than controls. In DM, intramuscular CD31 abundances were significantly reduced, which indicated vascular rarefaction. Muscular CXCR6 was elevated in both diseases. Circulating CXCL-16 was higher in DM and NM in contrast, compared to controls. Serum from patients with DM but not NM induced a profound upregulation of mRNS expression of CD31 and IL-6 in cultured myotubes.

Conclusion

Our study demonstrates the loss of intramuscular microvessels in DM, accompanied by endothelial activation in DM and NM. Vascular regeneration was impaired in DM and NM. The findings suggest a role for inflammation-associated vascular damage in the pathogenesis of DM.

Pathophysiological Concepts and Treatment of Camptocormia

Camptocormia is a disabling pathological, non-fixed, forward bending of the trunk. The clinical definition using only the bending angle is insufficient; it should include the subjectively perceived inability to stand upright, occurrence of back pain, typical individual complaints, and need for walking aids and compensatory signs (e.g. back-swept wing sign). Due to the heterogeneous etiologies of camptocormia a broad diagnostic approach is necessary. Camptocormia is most frequently encountered in movement disorders (PD and dystonia) and muscles diseases (myositis and myopathy, mainly facio-scapulo-humeral muscular dystrophy (FSHD)). The main diagnostic aim is to discover the etiology by looking for signs of the underlying disease in the neurological examination, EMG, muscle MRI and possibly biopsy. PD and probably myositic camptocormia can be divided into an acute and a chronic stage according to the duration of camptocormia and the findings in the short time inversion recovery (STIR) and T1 sequences of paravertebral muscle MRI. There is no established treatment of camptocormia resulting from any etiology. Case series suggest that deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) is effective in the acute but not the chronic stage of PD camptocormia. In chronic stages with degenerated muscles, treatment options are limited to orthoses, walking aids, physiotherapy and pain therapy. In acute myositic camptocormia an escalation strategy with different immunosuppressive drugs is recommended. In dystonic camptocormia, as in dystonia in general, case reports have shown botulinum toxin and DBS of the globus pallidus internus (GPi-DBS) to be effective. Camptocormia in connection with primary myopathies should be treated according to the underlying illness.

Rechallenge with temozolomide with different scheduling is effective in recurrent malignant gliomas

Treatment of recurrent malignant glioma, which has a poor patient prognosis, has not been standardised. Moreover, it is unclear whether repeated treatment with temozolomide is effective in patients who received previous temozolomide treatment before developing a recurrence. Here, we present the results of a high-dose individually adapted 21-day regimen demonstrating that rechallenge is effective even in patients expressing O6-methylguanine-DNA methyltransferase (MGMT) in the tumor. Twenty-one patients with recurrent malignant gliomas pre-treated with temozolomide, 18 WHO IV glioblastoma (GBM) and 3 WHO III patients, received 100 mg/m2 temozolomide on days 1-21/28. The GBM patients had a median Karnofsky performance status of 60% and a median age of 54.8 years. Blood counts decreased continuously, enabling a gradual dose adaptation. When blood counts dropped below normal values, temozolomide was applied on days 1-5/7. Dosage was reduced to 50-75 mg/m2 in 11 patients and gradually increased up to 130 mg/m2 in 3 patients. WHO grade 3/4 toxicity was hematological in 3 patients and non-hematological in 3 patients. In GBM patients (n=18), response after >3 months was complete in 3 patients, partial in 1 (22%), stable disease in 7 (39%) and progressive disease in 7 (39%). Progression-free survival at 6 months (PFS-6M) was 39%. Median survival was 9.1 months from relapse and 17.9 months overall. Of the patients with unmethylated MGMT promoter, 2/7 were progression-free for >6 (15 and 19) months. The data indicate that rechallenge with near-continuous, higher-dose temozolomide (100 mg/m2 on days 1-21/28 or days 1-5/7 with individual dose adaptation) is also feasible in patients with critical blood counts. Objective responses can be achieved even after relapse during a conventional 5/28-day regimen. The resistance of tumors characterized by unmethylated MGMT promoter may be overcome by near continuous temozolomide administration, which is probably most effective with a 5/7-day schedule. In spite of the relatively poor clinical prognosis, the data indicate that rechallenge with temozolomide with a dose-dense and long-lasting administration protocol is tolerable and comparable with other reported treatment protocols involving temozolomide.

Detection of classical and atypical/Nor98 scrapie by the paraffin-embedded tissue blot method

The paraffin-embedded tissue (PET) blot method was used to investigate sections of the central nervous system and lymphatic tissues from 24 cases of classical scrapie and 25 cases of atypical/Nor98 scrapie in sheep and four healthy control sheep. The PET blot detected deposits of PrP(Sc) in the brain tissue of all 49 sheep with scrapie but no PrP(Sc) labelling could be detected in the control sheep. By contrast, not all the atypical/Nor98 scrapie cases were detectable by immunohistochemistry. The high sensitivity of the PET blot method made it possible to observe that in some atypical/Nor98 cases, deposits of PrP(Sc) may be restricted to supratentorial brain structures and that the diagnosis may be missed when only testing the obex area, where deposits are common in classical scrapie, and the cerebellar structures, where deposits are considered to be common in atypical/Nor98 cases.

A selection system to study C5a-C5a-receptor interactions: phage display of a novel C5a anaphylatoxin, Fos-C5aAla27

Binding and effector domains of the human anaphylatoxin C5a have been determined by either site directed mutagenesis or synthetic peptide studies. However, the lack of specific selection methods, which allow direct investigation of C5a-C5a-receptor interaction made these studies laborious. To overcome these limitations we have constructed a novel Fos-C5a expressed on the tip of a filamentous phage. To guarantee for a free C-terminus which is required for C5a activity C5a cDNA was cloned into the phagemid vector pJuFo. Helper phage infection of pJuFc-C5a transformed cells resulted in a mutant phage displaying Fos-C5a on its surface. However studies with Bt2cAMP differentiated U937 cells revealed that phage displayed Fos-C5a is functional inactive. Subsequently we replaced a nonconserved cysteine residue at position 27 by alanine and obtained Fos-C5aAla27. Both the purified and the phage displayed Fos-C5aAla27 proteins were functional active and induced enzyme release from differentiated U937 cells. In addition, purified Fos-C5aAla27 exhibited the same binding profile as compared to rhC5a. Fos-C5aAla27 displaying phages were mixed with phage harboring only the pJuFo plasmid at a ratio of 10(6). After four successive rounds of panning on differentiated U937 cells Fos-C5aAla27 phages were enriched to 100% as shown by C5a-specific ELISA. We expect this approach to prove helpful for studying C5a-C5a-receptor interactions. i.e. to screen C5a libraries for high affinity binders with agonistic or antagonistic properties directly on cells.

Genotypic identification of mycobacteria by nucleic acid sequence determination: report of a 2-year experience in a clinical laboratory

Clinical isolates of Mycobacterium spp. were identified by direct sequence determination of 16S rRNA gene fragments amplified by polymerase chain reaction. Identification was based on a hypervariable region within the 16S rRNA gene in which mycobacterial species are characterized by species-specific nucleotide sequences. A manually aligned data base including the signature sequences of 52 species of mycobacteria easily allowed rapid and correct identification. The results of this study demonstrate that polymerase chain reaction-mediated direct sequence determination can be used as a rapid and reliable method for the identification of mycobacteria in the clinical laboratory. In addition, the prompt recognition of previously undescribed species is now feasible.

Molecular basis of streptomycin resistance in Mycobacterium tuberculosis: alterations of the ribosomal protein S12 gene and point mutations within a functional 16S ribosomal RNA pseudoknot

Multidrug-resistant strains of Mycobacterium tuberculosis have resulted in several recent outbreaks. Recognition of drug resistance is important both for treatment and to prevent further transmission. Here we use molecular biology techniques to study the basis of streptomycin resistance in single and multidrug-resistant M. tuberculosis. We demonstrate that streptomycin resistance is associated with mutations implicated in ribosomal resistance. The mutations found either lead to amino acid changes in ribosomal protein S12 or alter the primary structure of the 16S rRNA. The 16S rRNA region mutated perturbs a pseudoknot structure in a region which has been linked to ribosomal S12 protein.

The effect of modification of cytosines in Escherichia coli 16-S rRNA on reconstitution and function of 30-S ribosomes

O-Methylhydroxylamine (methoxyamine) was used for selective modification of cytosine residues in Escherichia coli 16-S rRNA. It was shown that cytosines accessible for methoxyamination are randomly distributed along the 16-S rRNA chain. Preparations of methoxyaminated 16-S rRNA, containing 2--130 modified cytosines/chain, still retained the ability to bind 30-S proteins, but the physical assembly of reconstituted particles was incorrect. The protein compositions of the reconstituted and native particles did not differ qualitatively from each other. However, the amount of protein in reconstituted particles decreased with an increasing number of methoxyaminated cytosines in 16-S rRNA. The particles obtained sedimented slower than native 30-S subunits, lost their ability to associate with 50-S ribosomes and to bind native phage f2 RNA. In contrast, modification of 16-S rRNA did not affect binding of poly(U) by reconstituted particles.

[Research concerning carriage of school-children (author's transl)]

By this research the percentage of school-children living in a mainly rural district in Nether Saxony whose carriage is endangered is to be stated and besides that it is to be examined whether and how far orthopedic training, practised by special nurses for physical training, can help to improve their carriage.