Physiology and pathophysiology of nitrosative and oxidative stress in osteoarthritic joint destruction

Osteoarthritis (OA) is one of the most common chronic diseases, with increasing importance due to increased life expectancy. On a cellular level, the pathophysiology of joint function impairment and ultimate destruction associated with OA remains poorly understood. Free radicals are highly reactive molecules involved in both normal intracellular signal transduction and degenerative cellular processes. An imbalance between the free radical burden and cellular scavenging mechanisms, defined as oxidative stress, has been identified as a relevant factor in OA pathogenesis. This literature review elucidates the involvement of nitrosative and oxidative stress in cellular ageing in joints, cell senescence, and apoptosis. Free radical exposure is known to promote cellular senescence and apoptosis, and the involvement of radical oxygen species (ROS) in inflammation, fibrosis control, and pain nociception has been proven. A relatively novel approach to OA pathophysiology considers the joint to be a dynamic system consisting of 3, continuously interacting compartments, cartilage, synovial tissue, and subchondral bone. Current knowledge concerning free radical involvement in paracrine signalling in OA is reviewed. The interrelationship between oxidative imbalances and OA pathophysiology may provide a novel approach to the comprehension, and therefore modification, of OA disease progression and symptom control.     

A short amino-terminal part of Arabidopsis phytochrome A induces constitutive photomorphogenic response

Phytochrome A (phyA) is the dominant photoreceptor of far-red light sensing in Arabidopsis thaliana. phyA accumulates at high levels in the cytoplasm of etiolated seedlings, and light-induced phyA signaling is mediated by a complex regulatory network. This includes light- and FHY1/FHL protein-dependent translocation of native phyA into the nucleus in vivo. It has also been shown that a short N-terminal fragment of phyA (PHYA406) is sufficient to phenocopy this highly regulated cellular process in vitro. To test the biological activity of this N-terminal fragment of phyA in planta, we produced transgenic phyA-201 plants expressing the PHYA406-YFP (YELLOW FLUORESCENT PROTEIN)-DD, PHYA406-YFP-DD-NLS (nuclear localization signal), and PHYA406-YFP-DD-NES (nuclear export signal) fusion proteins. Here, we report that PHYA406-YFP-DD is imported into the nucleus and this process is partially light-dependent whereas PHYA406-YFP-DD-NLS and PHYA406-YFP-DD-NES display the expected constitutive localization patterns. Our results show that these truncated phyA proteins are light-stable, they trigger a constitutive photomorphogenic-like response when localized in the nuclei, and neither of them induces proper phyA signaling. We demonstrate that in vitro and in vivo PHYA406 Pfr and Pr bind COP1, a general repressor of photomorphogenesis, and co-localize with it in nuclear bodies. Thus, we conclude that, in planta, the truncated PHYA406 proteins inactivate COP1 in the nuclei in a light-independent fashion.     

Heterogeneous pattern of retinal nerve fiber layer in multiple sclerosis. High resolution optical coherence tomography: potential and limitations

Background

Recently the reduction of the retinal nerve fibre layer (RNFL) was suggested to be associated with diffuse axonal damage in the whole CNS of multiple sclerosis (MS) patients. However, several points are still under discussion. (1) Is high resolution optical coherence tomography (OCT) required to detect the partly very subtle RNFL changes seen in MS patients? (2) Can a reduction of RNFL be detected in all MS patients, even in early disease courses and in all MS subtypes? (3) Does an optic neuritis (ON) or focal lesions along the visual pathways, which are both very common in MS, limit the predication of diffuse axonal degeneration in the whole CNS? The purpose of our study was to determine the baseline characteristics of clinical definite relapsing-remitting (RRMS) and secondary progressive (SPMS) MS patients with high resolution OCT technique.

Methodology

Forty-two RRMS and 17 SPMS patients with and without history of uni- or bilateral ON, and 59 age- and sex-matched healthy controls were analysed prospectively with the high resolution spectral-domain OCT device (SD-OCT) using the Spectralis 3.5mm circle scan protocol with locked reference images and eye tracking mode. Furthermore we performed tests for visual and contrast acuity and sensitivity (ETDRS, Sloan and Pelli-Robson-charts), for color vision (Lanthony D-15), the Humphrey visual field and visual evoked potential testing (VEP).

Principal Findings

All 4 groups (RRMS and SPMS with or without ON) showed significantly reduced RNFL globally, or at least in one of the peripapillary sectors compared to age-/sex-matched healthy controls. In patients with previous ON additional RNFL reduction was found. However, in many RRMS patients the RNFL was found within normal range. We found no correlation between RNFL reduction and disease duration (range 9–540 months).

Conclusions

RNFL baseline characteristics of RRMS and SPMS are heterogeneous (range from normal to markedly reduced levels).     

Characterization of 13 newly isolated strains of anaerobic, cellulolytic, thermophilic bacteria

Characteristics of 13 newly isolated thermophilic, anaerobic, and cellulolytic strains were compared with previously described strains of Clostridium thermocellum: ATCC 27405 and JW20 (ATCC 31549). Colony morphology, antibiotic sensitivity, fermentation end-products, and cellulose degradation were documented. All 13 strains were sensitive to erythromycin (5 μg/ml) and chloramphenicol (25 μg/ml), and all strains but one were sensitive to kanamycin (20 μg/ml). Polymerase chain reaction (PCR) amplification using primers based on gene sequences from C. thermocellum ATCC 27405 was successful for all 13 strains in the case of the hydrogenase gene and 11 strains in the case of phosphotransacetylase/acetate kinase genes. Ten strains amplified a product of the expected size with primers developed to be specific for C. thermocellum 16SrRNA primers. Two of the 13 strains did not amplify any product with the PCR primers designed for the phosphotransacetylase/acetate kinase and 16SrRNA primers. A MboI-like GATC- recognizing restriction activity was present in all of the five strains examined. The results of this study have several positive implications with respect to future development of a transformation system for cellulolytic thermophiles. Journal of Industrial Microbiology & Biotechnology (2001) 27, 275–280. Received 12 September 2000/ Accepted in revised form 20 November 2000     

A simple and rapid microwave-assisted hematoxylin and eosin staining method using 1,1,1 trichloroethane as a dewaxing and a clearing agent

The use and practicability of microwave-assisted staining procedures in routine histopathology has been well established for more than 17 years. In the study reported here, we aimed to examine an alternative approach that would shorten the duration of dewaxing and clearing steps of hematoxylin and eosin (H & E) staining of paraffin sections by using a microwave oven. Although xylene is one of the most popular dewaxing and clearing agents, its flammability restricts its use in a microwave oven; thus we preferred 1,1,1 trichloroethane, which is not flammable, as the dewaxing and clearing agent in the present study. In Group I and Group II (control groups), intestine was processed with xylene and 1,1,1 trichloroethane, respectively. The sections were then stained with H & E according to the conventional staining protocol at room temperature and subdivided into two groups according to the duration of dewaxing and clearing in xylene. In Groups III and IV (experimental groups) similar tissues were processed with xylene and 1,1,1 trichloroethane, respectively; however, sections from these groups were divided into four subgroups to study the period required for dewaxing and clearing in 1,1,1 trichloroethane, then stained with H & E in the microwave oven at 360 W for 30 sec. Our conventional H & E staining procedure, which includes dewaxing, staining and clearing of sections, requires approximately 90 min, while our method using 1,1,1 trichloroethane and microwave heating required only 2 min. Our alternative method for H & E staining not only reduced the procedure time significantly, but also yielded staining quality equal or superior to those stained the conventional way. Our results suggest that 1,1,1 trichloroethane can be used effectively and safely as a dewaxing and clearing agent for H & E staining in a microwave oven.     

Computed tomography of the thorax in rabbits: a prospective study in ten clinically healthy New Zealand White rabbits

Background

Literature investigating the normal cross-sectional anatomy of rabbits with computed tomography (CT) is sparse and incomplete. The purpose of the present study was to investigate the normal thoracic structures, in particular the cranial thorax, with CT angiography in 10 clinically healthy New Zealand White (NZW) rabbits.

Results

Absolute and relative measurements of the trachea, heart, thoracic caudal vena cava and aorta, right and left principal bronchi, right and left caudal lobar bronchi and the accompanying branches of the right and left pulmonary artery and vein, right and left lung volume and lung density were taken. The three lobes of the thymus (right ventral, right dorsal and left thoracic lobes) were identified in all rabbits. Both the right dorsal and left thoracic lobes of the thymus extended between the heart and thoracic wall in all individuals with the left lobe reaching more caudally in seven animals. Consequently, the craniocaudal extension of the left lung was smaller than the right lung in these rabbits. Volume of the left lung was significantly smaller than the right (P = 0.005). The cranial mediastinal, right and left tracheobronchial and the aortic thoracic lymph nodes were very small and identified in four, four, seven and ten rabbits, respectively. The heart took up a median of 4.0 intercostal spaces, and in seven rabbits, it was located in the 2nd–5th intercostal space. Median relative cardiac height and width measured 74 and 88%, respectively. The median angle of the trachea to the spine was 5°. Median density between the right and left lung did not significantly differ (? 549 and ? 583 Hounsfield units, respectively). In all but one rabbit, atelectasis was present and classified as mild, moderate or severe in six, two and one individuals, respectively. Mild subclinical bronchopneumonia was diagnosed in seven rabbits.

Conclusions

The present study provides species-specific anatomical CT information and reference values for structures in the thorax of the NZW rabbit. Subclinical bronchopneumonia appears to be a common CT finding.