Exogenous Modulation of TGF-β1 Influences TGF-βR-III-Associated Vascularization during Wound Healing in Irradiated Tissue

BACKGROUND AND PURPOSE: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial cell carcinomas of the head and neck region, wound-healing disorders occur. Previous experimental studies showed altered expression of transforming growth factor-(TGF-)beta isoforms following surgery in irradiated graft beds. Altered levels of TGF-beta(1) are reported to promote fibrosis and to suppress vascularization during wound healing, whereas expression of TGF-beta receptor-III (TGF-betaR-III) is associated with vascularization. The aim of the study was to analyze the influence of anti-TGF-beta(1) treatment on TGF-betaR-III-associated vascularization in the transition area between irradiated graft bed and graft. MATERIAL AND METHODS: Wistar rats (male, weight 300-500 g) underwent preoperative irradiation of the head and neck region with 40 Gy (four fractions of 10 Gy each; n = 16 animals). A free myocutaneous gracilis flap taken from the groin was then transplanted to the neck in all rats. The time interval between operation and transplantation was 4 weeks. Eight animals received 1 micro g anti-TGF-beta(1) into the graft bed by intradermal injection on days 1-7 after surgery. On days 3, 7, 14, 28, 56, and 120, skin samples were taken from the transition area between transplant and graft bed and from the graft bed itself. Immunohistochemistry was performed using the ABC-POX method to analyze the TGF-betaR-III and E-selectin expression. Histomorphometry was performed to analyze the percentage and the area of positively stained vessels. RESULTS: A significantly higher expression of TGF-betaR-III was seen in the irradiated and anti-TGF-beta(1)-treated graft bed in comparison to the group receiving preoperative irradiation followed by transplantation alone. The percentage of TGF-betaR-III positively staining capillaries from the total amount of capillaries in the anti-TGF-beta(1)-treated graft bed was higher than in the group irradiated only. The total area of capillaries was also higher in the TGF-beta(1)-treated group. CONCLUSION: Neutralizing of TGF-beta(1) activity in irradiated tissue undergoing surgery leads to a higher expression of TGF-betaR-III and increased vascularization. TGF-betaR-III seems to be associated with newly formed blood vessels during neovascularization in wound healing.     

Modulation of calcium-activated chloride current via pH-induced changes of calcium channel properties in cone photoreceptors.

The activity of calcium-activated chloride channels is controlled through the complex interaction of cellular mechanisms affecting calcium entry, buffering, and extrusion, and an unknown stoichiometric relation between intracellular Ca concentration and Cl channel activation. Here, we show that calcium-activated chloride current [ICl(Ca)] in cone photoreceptors is also highly sensitive to external pH, being strongly reduced by acidification and enhanced by alkylinization of the bathing medium. We propose that this modulation is accounted for by the pH sensitivity of Ca channel activation and permeation, already well characterized in other cells, which we now extend to cone photoreceptor Ca channels. Acidification of the external medium from a control pH of 7.4 shifts the Ca channel activation range positively by about 10 mV at pH 6.8, reducing the magnitude of calcium current with a consequent reduction of chloride current. Alkylinization shifts the Ca channel activation range negatively by about 8 mV at pH 8 and produces larger calcium currents during step depolarizations that in turn elicit larger chloride tail currents. Modulation of ICl(Ca) by pH suggests other consequences of the pH-induced shift in Ca channel gating, for one, modification of Ca-dependent transmitter release, which could be especially significant in photoreceptors where the cell's operating voltage range overlaps only the lower end of the Ca channel activation range.     

Modulation of dopamine function by glycine in the nucleus accumbens of the brain of the rat

The effects of glycine on the phasic changes in locomotor activity in the rat, caused by a persistent infusion of dopamine (DA) into the nucleus accumbens (ACB) were investigated. Dopamine (25 μg/24 hr), infused into the nucleus accumbens for 13 days, caused hyperactivity, with two peaks occurring on days 3–4 and 9–11. Glycine (12.5 or 25 μg/24 hr) infused into the nucleus accumbens on its own did not alter the locomotor activity, yet when infused at the same time as DA (25 μg/24 hr), glycine (12.5 or 25 μg/24 hr) inhibited the development of the first peak of hyperactivity induced by DA, with no effect on the second peak. A larger dose of glycine (50 μg/24 hr), infused alone, significantly increased locomotor activity, and a combination of this dose with DA (25 μg/24 hr), led to a temporal shift in the response to DA such that the first peak of hyperactivity was delayed to “fuse” with the second peak. The locomotor response to a threshold dose of DA (6.25 μg/24 hr) plus glycine (50 μg/24 hr) was no greater than could be accounted for by the hyperactivity response to glycine alone (50 μg/24 hr). Strychnine (10 μg/24 hr), infused into the nucleus accumbens, produced no alteration in locomotor activity. Similarly, when infused together with DA (25 μg/24 hr), strychnine (10 μg/24 hr) caused no significant alteration in the phasic hyperactivity induced by DA. However, strychnine (10 μg/24 hr), infused together with DA and glycine (25 and 12.5 μg/24 hr respectively), prevented the inhibition by glycine of the first peak of hyperactivity induced by DA. The results indicate that while glycine may not normally exert a tonic modulatory influence on those mechanisms in the nucleus accumbens which regulate locomotor activity, when applied exogenously glycine can partially moderate the locomotor response to DA, through an action on strychnine-sensitive receptors.     

Coexisting rheumatoid arthritis and ankylosing spondylitis

Since the second publication by some of the present authors in which 10 patients with coexisting rheumatoid arthritis (RA) and ankylosing spondylitis (AS) were described, 7 new cases have been found. For accuracy, all cases of the original study still available were reexamined. Of the total of 17 cases, 13 were male and 4 female. All had positive tests for rheumatoid factor and 6 had subcutaneous nodules. The male predominance and the frequency of nodules are consistent with other publications. In addition, our study demonstrates the strong association of each of these 2 diseases with its genetic marker: the antigen HLA-DR4 was present in 8 of 12 cases tested and the antigen HLA-B27 was present in 16 of the 17 cases. The coexistence of these 2 classical rheumatological entities in the same patient appears to occur by chance and is probably often overlooked.     

Leitbild für die Leitstelle — Gefahren im Einsatz — Notfallmedizin im DRG-Zeitalter

Zusammenfassung Die 20. notfallmedizinische Jahrestagung der Arbeitsgemeinschaft Südwestdeutscher Notärzte (agswn) behandelte auch in diesem Jahr aktuelle berufspolitische Themen. Aktuelle Entwicklungen zur Verbesserung der Arbeitsabläufe in den Leitstellen wurden dargestellt, EDV-gestützte Systeme zur Notrufabfrage, die Vernetzung der Leitstellen und technische Verbesserungen der Leitstellensysteme genannt. Die Gefahren im Rettungsdienst waren ein weiterer Schwerpunkt der Tagung. Eine Ansteckungsgefahr bei Infektionstransporten bei MRSA-Patienten ist bei sachgemäßem Verhalten nicht zu befürchten. Weiterhin wurden die Möglichkeiten des terroristischen Einsatzes von biologischen Waffen realistisch deutlich relativiert. Amoklagen stellen dagegen eine nur schwer kalkulierbare Gefahrensituation dar. Als 3. Themenschwerpunkt wurden die besonderen Herausforderungen der Notfallmedizin im DRG-Zeitalter umrissen. Die Änderung des Einsatzspektrums und die Reduktion von Notarztstandorten erfordert die Bildung von Kompetenzzentren und eine hohe Qualifikation der Notärzte.     

Enhanced chondrogenesis and Wnt signaling in PTH-treated fractures.

Studies have shown that systemic PTH treatment enhanced the rate of bone repair in rodent models. However, the mechanisms through which PTH affects bone repair have not been elucidated. In these studies we show that PTH primarily enhanced the earliest stages of endochondral bone repair by increasing chondrocyte recruitment and rate of differentiation. In coordination with these cellular events, we observed an increased level of canonical Wnt-signaling in PTH-treated bones at multiple time-points across the time-course of fracture repair, supporting the conclusion that PTH responses are at least in part mediated through Wnt signaling. INTRODUCTION: Since FDA approval of PTH [PTH(1-34); Forteo] as a treatment for osteoporosis, there has been interest in its use in other musculoskeletal conditions. Fracture repair is one area in which PTH may have a significant clinical impact. Multiple animal studies have shown that systemic PTH treatment of healing fractures increased both callus volume and return of mechanical competence in models of fracture healing. Whereas the potential for PTH has been established, the mechanism(s) by which PTH produces these effects remain elusive. MATERIALS AND METHODS: Closed femoral fractures were generated in 8-wk-old male C57Bl/6 mice followed by daily systemic injections of either saline (control) or 30 microg/kg PTH(1-34) for 14 days after fracture. Bones were harvested at days 2, 3, 5, 7, 10, 14, 21, and 28 after fracture and analyzed at the tissue level by radiography and histomorphometry and at the molecular and biochemical levels level by RNase protection assay (RPA), real-time PCR, and Western blot analysis. RESULTS: Quantitative muCT analysis showed that PTH treatment induced a larger callus cross-sectional area, length, and total volume compared with controls. Molecular analysis of the expression of extracellular matrix genes associated with chondrogenesis and osteogenesis showed that PTH treated fractures displayed a 3-fold greater increase in chondrogenesis relative to osteogenesis over the course of the repair process. In addition, chondrocyte hypertrophy occurred earlier in the PTH-treated callus tissues. Analysis of the expression of potential mediators of PTH actions showed that PTH treatment significantly induced the expression of Wnts 4, 5a, 5b, and 10b and increased levels of unphosphorylated, nuclear localized beta-catenin protein, a central feature of canonical Wnt signaling. CONCLUSIONS: These results showed that the PTH-mediated enhancement of fracture repair is primarily associated with an amplification of chondrocyte recruitment and maturation in the early fracture callus. Associated with these cellular effects, we observed an increase in canonical Wnt signaling supporting the conclusion that PTH effects on bone repair are mediated at least in part through the activation of Wnt-signaling pathways.