Differential regulation of matrix degrading enzymes in a TNFalpha-induced model of nucleus pulposus tissue degeneration

Intervertebral disc degeneration occurs commonly and is linked to persistent back pain and the development of disc herniation. The mechanisms responsible for tissue catabolism have not yet been fully elucidated. Previously we characterized an in vitro model of TNFalpha-induced nucleus pulposus degeneration, which demonstrates decreased expression of matrix macromolecules, increased expression of matrix degrading enzymes, and the activation of aggrecanase-mediated proteoglycan degradation [Seguin, C.A., Pilliar, R.M., Roughley, P.J., and Kandel, R.A. 2005. Tumor necrosis factor-alpha modulates matrix production and catabolism in nucleus pulposus tissue. Spine 30: 1940-1948]. This study explores the intracellular pathways activated during TNFalpha-induced matrix degradation. We demonstrate that in nucleus pulposus cells, the p38 and JNK pathways regulate induction of MMP-1 and -3; p38, JNK, and NF-kappaB regulate the induction of MMP-13; and ERK regulates the up-regulation of MT1-MMP mRNA in response to TNFalpha. Induction of ADAMTS-4 and -5 mRNA occurred downstream of NF-kappaB activation. Depletion of tissue proteoglycans was mediated by ERK and NF-kappaB-dependent "aggrecanase" activity, suggesting MT1-MMP and ADAMTS-4 and -5 as effectors of TNFalpha-induced tissue catabolism.

[The influence of twenty years of Rh (D) factor incompatibility immunoprophylaxis on reducing the occurrence of hemolytic disease in newborns]

The study presents the frequency of occurrence of newborn haemolitic disease caused by Rh (D) system incompatibility in the years 1980-1999. Serological incompatibility prophylaxis was introduced in 1980. Routine use of anti-D immunoglobulin has led to a significant reduction in the number of newborns with haemalitic disease caused by Rh (D) system incompatibility. In the years 1990-1999 no newborn deaths attributable to this immunization were recorded. Long-term prophylaxis has greatly reduced the occurrence of this pathology in newborns. Nonetheless, in contemporary perinatology we continue to record occasional cases of haemolitic disease in newborns caused by blood group incompatibility between mother and foetus.

[Cesarean section by the Misgav Ladach+ with the abdominal opening surgery by the Joel Cohen method]

The purpose of this study was to compare 90 Misgav-Ladach cesarean section by the Joel-Cohen method with 45 others with Pfannenstiel incision. The Misgav-Ladach technique involves the Joel-Cohen method, that is a superficial transverse cut in the cutis, a small midline incision in the fascia, then blunt preparation of deeper layers, including the peritoneum, followed by manual transverse traction applied to tear the recti muscles and subcutis. The uterus is also opened using the blunt preparation after a small cut in the midline. After the delivery of the fetus and placenta the uterus is lifted through the incision onto the draped abdominal wall. Then the uterus is closed with one layer of continuous vicryl suture. The abdomen is closed by a continuous suture of fascia, and widely spaced silk stitches of the skin. We sometimes use continuous suture of the skin. We do not close visceral and parietal peritoneum, recti muscles and subcutis. In our experience Misgav-Ladach method is 50% less time consuming, it reduces blood loss by about 250 ml. and allows for a much faster delivery of the fetus than Pfannenstiel method. The post operative outcome of the two methods is similar. Using the blunt preparation in the Joel-Cohen method causes less trauma and shortens convalescence time. We therefore recommend Misgav-Ladach method for cesarean section.

The role of reflex activity in the regulation of muscle tone in rats

The aim of the study was to assess the contribution of reflex activity to the regulation of muscle tone in rats. The experiment was carried out on young Wistar male and female rats. The hindfoot of a rat was flexed or extended at the ankle joint by 25 deg over 250 ms. The resistance of the foot to passive movements, as well as the electromyographic (EMG) activity in the gastrocnemius and the tibialis anterior muscles, were recorded simultaneously. During passive movements, reflex EMG activity developed simultaneously in both antagonistic muscles of the foot. Three components were distinguished: a short-latency EMG-A (within the first 0-20 ms of a movement), long-latency EMG-B (within 60-160 ms), and EMG-C (within 220-340 ms). When the amplitudes of EMG-B and EMG-C components of the gastrocnemius muscle reflex response were greater than 50 microV, a significant correlation was found between them and the maximum resistance of the hindfoot (MMGmax) during flexion, whereas no such correlation was observed for the tibialis anterior muscle. No correlation was found when the amplitudes of the log-latency components of the gastrocnemius muscle were less than 50 microV. Moreover, no correlation was observed between the EMG-A and the MMG(max). The above results suggest that: (1) the muscle tone of the gastrocnemius muscle in rats seems to be regulated by long-latency (supraspinal) reflexes only when the level of EMG activity exceeds a critical threshold of ca 50 microV; (2) when the level of EMG activity is lower, a major role in the resistance of hindlimb muscles is played by some non-neuronal factors; and (3) the proposed animal model emphasizes new aspects of the reflex which may be useful in a search for basic mechanisms underlying changes in the muscle tone.