Opposite reaction of ERK and JNK in ischemia vulnerable and resistant regions of hippocampus: involvement of mitochondria

Delayed ischemic death of neurones is observed selectively in CA1 region of hippocampus at 3-4 days of reperfusion. Signals generated immediately during and after ischemia are further propagated by a variety of kinases, proteases and phosphatases. Tissue samples from dorsal (vulnerable) and abdominal (resistant) parts of gerbil hippocampi were collected to determine the activation state of key signaling molecules: Akt, Raf-1, JNK, ERK1/2 in the course of reperfusion after 5 min of global cerebral ischemia. Western blot analysis of phosphorylated forms of the kinases revealed persistent activation of JNK, being limited mostly to vulnerable CA1 region. On the contrary, activation of ERK, although observed transiently in both parts, was enhanced for a longer time in the abdominal hippocampus. The levels of the active/phosphorylated Akt and Raf-1 kinases did not change significantly during the recovery period. No significant correlation between postischemic JNK activation and c-Jun phosphorylation or its contribution to AP1-like complex formation was found. In contrast, the amount of active JNK linked with mitochondrial membranes was significantly increased and preceded neuronal death in CA1. In the same period of time the AP1 complex, augmented in CA1 region, did not appear to contain a classical c-Fos protein. These results are consistent with the theory that either long-lasting activation of JNK and/or contrasting ERK and JNK activities in critical time of reperfusion, contribute to selective apoptosis of CA1 neurons. This, in connection with the translocation of activated JNK to mitochondria and time/regional differences in AP1 binding protein complexes can affect final postischemic outcome.     

Dysfunction of peripheral blood granulocyte oxidative metabolism in children with recurrent upper respiratory tract infections

Granulocytes play a key role in the defence against bacterial infections. Their dysfunction may both predispose to and result from infections. The oxidative metabolism of peripheral blood granulocytes was studied in 50 children aged from 1 to 10 years, with recurrent upper respiratory tract infections and/or tonsillar hypertrophy. Four groups of patients were recruited: 15 healthy controls, seven patients with idiopathic tonsillar hypertrophy, 12 patients with upper respiratory tract infections and 16 patients with upper respiratory tract infections with concurrent tonsillar hypertrophy. The ability of granulocytes to produce reactive oxygen species was assessed by nFMLP-induced chemiluminescence. Both increased and depressed granulocyte activity was observed in all studied groups, with the exception of controls. Altered granulocyte function was observed in 30% of patients in the idiopathic tonsillar hypertrophy group. In children with recurrent infections abnormal chemiluminescence results were found in from 75% to nearly 90% of patients. This preliminary study demonstrates the possible relationship between recurrent upper respiratory tract infections, tonsillar hypertrophy and impaired peripheral blood granulocyte chemiluminescence.     

Bone Turnover Rate in Postmenopausal Women: Bimodal Distribution?

There is considerable evidence that elevated bone turnover is an independent form of low bone mineral density (BMD) risk factor of osteoporotic fractures. The aim of our study was to test whether a group of postmenopausal women could be divided into subgroups of high and low bone turnover rate using different pairs of bone turnover markers (one resorption, one formation). Cluster analysis was used to obtain high and low bone turnover subgroups within the study group. A magnitude of difference in lumbar spine BMD (expressed as Z-score) between high- and low-turnover groups was used as a criterion of division success. According to this criterion, the division obtained with a urinary type I collagen crosslinked N-telopeptide/bone alkaline phosphatase pair of markers appeared to be the most significant. This method of separation of two subgroups was highly concordant with the division based on the upper thresholds of the normal values for those markers found for the premenopausal women. It seems that the observed existence of high-and low-turnover subject clusters is not an incidental phenomenon, because the effects obtained for the whole study group were further confirmed by the consistent results of cluster analysis, performed separately for two randomly selected subgroups (A and B) from the study group. The results obtained appear to support the view that bone turnover rate in postmenopausal women is distributed in the bimodal fashion. This finding seems to justify further investigations of more elaborated models, enabling clinicians to individually classify their patients as low- or high-turnover cases with higher efficiency, as in the case of cutoff values for single markers.     

Differentiated neuroblastoma cells are more susceptible to aluminium toxicity than developing cells

The influence of aluminium (20–50 μg/ml) on neuronal function was examined using electrophysiological techniques and neuroblastoma clone cells which offer a convenient model of differentiating and fully active neurons. Two specific questions were addressed: 1) Can differentiated cells maintain their normal excitable function when exposed to aluminium? 2) Can proper development of electrophysiological properties be achieved in its presence? We report that aluminium caused premature onset of deterioration in fully differentiated cells. Within 4–6 days they depolarized from ?29.3+-0.9 mV to levels lower than ?15 mV; compound polyphasic action potentials were gradually replaced by slow monophasic spikes before the final loss of excitable properties and structural deformations was noticed. Developing cells followed the normal pattern of differentiation in the presence of aluminium: within 7 days they extended neurites, hyperpolarized and exhibited polyphasic spikes. These results show that neuroblastoma cells are apparently less susceptible to aluminium's toxicity during the process of development than after differentiation. Possible mechanisms by which aluminium may exert its effects are discussed in view of these observations.     

Schwefelsäure-Vergiftung durch direkte Einführung der Säure ins Duodenum

Ohne Zusammenfassung     

Long-term outcome in the treatment of mandibular condylar fractures

Background. Fractures of the condylar process of the mandible, whether isolated or coexisting with other injuries, are often difficult to manage. Treatment outcome in patients with mechanical injuries of the temporomandibular joints and fractures of mandibular condylar process, which is an element of this joint, depends mostly when and how treatment is initiated. The goal of our study was to assess functional abnormalities in patients following fractures of the condylar process of the mandible in relation to the treatment method used. Material and methods. We analyzed patient documentation and the results of follow-up examinations of 147 patients hospitalized for fractures of the condylar process. This material included both isolated fractures of the condylar process and those accompanied by fractures of the body of the mandible. All mandibular body fractures were managed by means of multiplate osteosynthesis. Fractures of the condylar process were treated in a conservative-orthopedic manner or surgically, depending on the degree of shortening of the mandibular ramus. Anamnesis regarding pain and a functional examination of mandibular kinetics and audible effects gave a basis for assessing the function of temporomandibular joints following treatment. The Helkimo Dysfunction Index was used to assess changes in masticatory function and disorders in the temporomandibular joint. Results. Functional disturbances of the temporomandibular were observed in 38.1% of the examined patients. The most frequently observed symptoms of dysfunction were periodic pain and crackles on mandibular abduction, subluxation, deviation of the mandible, and slight limitation of jaw opening. The intensity depended mainly on when rehabilitation was commenced, and to a less degree on the type of treatment used. No joint dysfunctions were observed in patients of developmental age who sustained isolated condylar process fractures.     

Stromal cell-derived factor 1 promotes angiogenesis via a heme oxygenase 1-dependent mechanism

Stromal cell-derived factor 1 (SDF-1) plays a major role in the migration, recruitment, and retention of endothelial progenitor cells to sites of ischemic injury and contributes to neovascularization. We provide direct evidence demonstrating an important role for heme oxygenase 1 (HO-1) in mediating the proangiogenic effects of SDF-1. Nanomolar concentrations of SDF-1 induced HO-1 in endothelial cells through a protein kinase C zeta-dependent and vascular endothelial growth factor-independent mechanism. SDF-1-induced endothelial tube formation and migration was impaired in HO-1-deficient cells. Aortic rings from HO-1(-/-) mice were unable to form capillary sprouts in response to SDF-1, a defect reversed by CO, a byproduct of the HO-1 reaction. Phosphorylation of vasodilator-stimulated phosphoprotein was impaired in HO-1(-/-) cells, an event that was restored by CO. The functional significance of HO-1 in the proangiogenic effects of SDF-1 was confirmed in Matrigel plug, wound healing, and retinal ischemia models in vivo. The absence of HO-1 was associated with impaired wound healing. Intravitreal adoptive transfer of HO-1-deficient endothelial precursors showed defective homing and reendothelialization of the retinal vasculature compared with HO-1 wild-type cells following ischemia. These findings demonstrate a mechanistic role for HO-1 in SDF-1-mediated angiogenesis and provide new avenues for therapeutic approaches in vascular repair.     

T lymphocytes containing β-endorphin ameliorate mechanical hypersensitivity following nerve injury

Neuropathic pain is a debilitating consequence of nerve injuries and is frequently resistant to classical therapies. T lymphocytes mediate adaptive immune responses and have been suggested to generate neuropathic pain. In contrast, in this study we investigated T cells as a source of opioidergic analgesic β-endorphin for the control of augmented tactile sensitivity following neuropathy. We employed in vivo nociceptive (von Frey) testing, flow cytometry and immunofluorescence in wild-type and mice with severe combined immunodeficiency (SCID) subjected to a chronic constriction injury of the sciatic nerve. In wild-type mice, T lymphocytes constituted approximately 11% of all immune cells infiltrating the injury site, and they expressed β-endorphin and receptors for corticotropin-releasing factor (CRF), an agent releasing opioids from leukocytes. CRF applied at the nerve injury site fully reversed neuropathy-induced mechanical hypersensitivity in wild-type animals. In SCID mice, T cells expressing β-endorphin and CRF receptors were absent at the damaged nerve. Consequently, these animals had substantially reduced CRF-mediated antinociception. Importantly, the decreased antinociception was fully restored by transfer of wild-type mice-derived T lymphocytes in SCID mice. The re-established CRF antinociception could be reversed by co-injection of an antibody against β-endorphin or an opioid receptor antagonist with limited access to the central nervous system. We propose that, in response to CRF stimulation, T lymphocytes accumulating at the injured nerves utilize β-endorphin for activation of local neuronal opioid receptors to reduce neuropathy-induced mechanical hypersensitivity. Our findings reveal β-endorphin-containing T cells as a crucial component of beneficial adaptive immune responses associated with painful peripheral nerve injuries.     

Changes in the expression of ion channels, connexins and Ca2+-handling proteins in the sino-atrial node during postnatal development

There are important postnatal changes in the sino-atrial node (SAN), the pacemaker of the heart. Compared with the neonate, the adult has a slower intrinsic heart rate and a longer SAN action potential. These changes may be due to differences in ion channel expression. Consequently, we investigated postnatal developmental changes in the expression of ion channels and Ca(2+)-handling proteins in the SAN to see whether this is indeed the case. Using quantitative PCR, in situ hybridization and immunohistochemistry, we investigated the expression of ion channels, Ca(2+)-handling proteins and connexins in the SAN from neonatal (2-7 days of age) and adult (～6 months of age) New Zealand White rabbits. The spontaneous beating rate of adult SAN preparations was 21% slower than that of neonatal preparations. During postnatal development, quantitative PCR revealed a significant decline in the SAN of the following mRNAs: HCN4 (major isoform responsible for I(f)), Na(V)1.5 (responsible for I(Na)), Ca(V)1.3 (in part responsible for I(Ca,L)) and NCX1 (responsible for inward I(NaCa)). These declines could be responsible for the slowing of the pacemaker during postnatal development. There was a significant decline during development in mRNA for delayed rectifier K(+) channel subunits (K(V)1.5, responsible for I(K,ur), K(V)LQT1 and minK, responsible for I(K,s), and ERG, responsible for I(K,r)) and this could explain the prolongation of the action potential. In situ hybridization confirmed the changes observed by quantitative PCR. In addition, immunohistochemistry revealed hypertrophy of nodal cells during postnatal development. Moreover, there were complex changes in the expression of Ca(2+)-handling proteins with age. In summary, there are significant postnatal changes in the expression of ion channels and Ca(2+)-handling proteins in the SAN that could explain the established changes in heart rate and action potential duration that occur during normal development.