Reconstruction of the anterior cruciate ligament with a cyropreserved ACL allograft

Summary. The ACL in the rabbit is innervated by three types of nerve fibres. These subserve vasoconstriction, nociceptive and proprioceptive purposes. The aim of this paper was to investigate the revascularisation and reinnervation of cyropreserved ACL allografts in 22 New Zealand white rabbits. Cyropreserved grafts were used as they may excite less host immune response. Both microangiographic and immunohistochemical methods were used. We found that cryopreserved allografts exhibited little immune response, revascularisation was considerable by the 24th postoperative week and reinnervation was essentially complete by then. No mechanoreceptors were found in ACL allografts. In rabbits, the anatomical basis for the participation of ACL allografts in sensorimotor reflexes is not given before the twelfth week after transplantation.

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Résumé. Nous avons examiné par méthodes micro-angiographiques et immuno-histo-chimiques la revascularisation et l’innervation d’un allogreffon cryopréservé (os – ligament croisé antérieur – os), chez 22 lapins de Nouvelle Zélande. Au sein de la greffe, existe une hypervascularisation maximale à 6 semaines, persistante à 12 semaines et se normalisant 24 semaines après la transplantation. Le panicule adipeux du genou était une source importante pour la revascularisation du greffon. L’immuno-histo-chimie a montré la présence de 3 types de fibres nerveuses au sein du ligament croisé: des afférents sensoriels mécano-réceptifs, des afférents sensoriels nociceptifs et des efférents sympathiques vaso-moteurs. Les contr?les ont montré l’existence de plusieurs fibres des 3 types de nerf; les terminaisons sensitives étaient toutes des corpuscules de Ruffini. Il n’y avait pas de fibre nerveuse au sein de l’allogreffe du ligament croiséà 3 et 6 semaines après la transplantation. Des fibres d’aspect cicatriciel étaient détectées à 12 semaines, tandis que des contr?les plus tardifs montraient un nombre et une distribution presque normale des filets nerveux. Aucun récepteur mécanique ne fut trouvé dans l’allogreffe. Chez le lapin, les bases anatomiques de la participation sensitivo-motrice de l’allogreffe du ligament croisé antérieur n’existent pas avant la 12ème semaine après la transplantation.

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Accepted: 11 May 1995     

The effect of estrogens and dietary calcium deficiency on the extracellular matrix of articular cartilage in G?ttingen miniature pigs.

Clinical observations have suggested that estrogens are involved in the pathogenesis of postmenopausal osteoarthritis (OA). However, positive and negative associations between the incidence of OA and serum estrogen concentrations have been reported. In contrast to this, osteoporosis is regarded as a disease with a strong estrogen-dependent component. Moreover, there is an interaction between estrogen and calcium deficiency: calcium supplementation potentiates the effect of estrogen therapy. The present study was designed to investigate how estrogen deficiency affects the articular cartilage depending on calcium supply. The distribution of different types of glycosaminoglycans and collagens can be used as an indicator for extracellular matrix changes induced by estrogen deficiency. Different levels of dietary calcium were therefore fed to intact and ovariectomized G?ttingen miniature pigs for one year before articular cartilage was harvested. The histochemical staining for heavy sulfated glycosaminoglycans in the extracellular matrix of ovariectomized miniature pigs, especially of those fed with a low calcium diet, was stronger in comparison to intact animals. In intact animals type II-collagen was immunodetected in all zones of unmineralized and mineralized articular cartilage, while immunostaining for this protein was negative to weak in the deep radiated fiber zone of ovariectomized minipigs. These results suggest that the synthesis of heavy sulfated glycosaminoglycans and immunohistochemically detectable type II-collagen is possibly influenced by estrogen deficiency. In conclusion, under estrogen deficiency, the extracellular matrix of articular cartilage underwent similar changes to those observed in physiologically aging cartilage where keratan sulfate is increased as a heavy sulfated glycosaminoglycan.     

5-Oxo-1H-3,4,5,6-tetrahydro-2,6-methano-2-benzazocin und seine Reduktionsprodukte

3,4,5,6-Tetrahydro-1H-2,6-methano-2-benzazocin-5-one and its Reduction Products 3,4,5,6-Tetrahydro-1H-2,6-methano-2-benzazocin-5-one 2 has been prepared by oxidation of N-benzyl-4-piperidone 1 with cerium(IV) sulfate. 2 was reduced by sodium borohydride or lithium aluminum hydride in various solvents. The stereoselectivity of these reductions is high. The configurations of the epimeric alcohols were determined by ¹H-NMR spectroscopy.     

Cerebrospinal fluidCHOLINESTERASES—MARKERS for loss ofcholinergic basal forebrain neurons?

The present study was conducted to test the hypothesis that cholinergic basalforebrain neurons are a major source of cerebrospinal fluid (CSF) cholinesterases. To address thisquestion enzyme activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inboth CSF and parietal cortex were assayed following selective lesion of basal forebrain cholinergicneurons by a single intracerebroventricular application of the cholinergic immunotoxin192IgG-saporin. Cholinergic immunolesions led to a dramatic decrease in total AChE activity inparietal cortex, which was due to the specific loss of the G4 molecular form while the activity ofthe G1 form was increased as compared to nonlesioned animals. In contrast, the total enzymeactivity of BChE and its molecular forms were not affected by cholinergic lesion in both parietalcortex and CSF. The data suggest, that cholinergic basal forebrain neurons are seemingly not amajor source of cholinesterases in the CSF, and do not provide any evidence for using CSFcholinesterases as a diagnostic marker of basal forebrain cholinergic cell loss in humans.     

Disorders of thermoregulation in adaptation to external cold and heat stimuli in patients with atopic eczema

Patients suffering from atopic eczema (AE) often exhibit disturbances of various neurovegetative (in particular, vasomotoric) skin functions. Thus, in 21 patients with AE we studied the response of the skin of one forearm to standardized 15-min exposure of the other arm to a cold and a warm bath (17 degrees-18 degrees C and 40 degrees-41 degrees C respectively). The results were compared with those in 23 age- and sex-matched healthy controls under similar environmental conditions. In most patients, during exposure of one forearm to warmth the skin temperature of the contralateral forearm remained unchanged or decreased slightly, whereas exposure to cold induced either a slight rise in skin temperature or an almost indiscernible decrease. In contrast to the normal temperature reaction of the non-exposed forearm to warmth exposure of the contralateral arm in most controls, our findings in atopic patients indicated a "rigid" or even "paradoxical" response to thermic stimuli. This abnormal pattern of thermoregulation may reflect an intrinsic disturbance of the peripheral and hypothalamic autonomous system involved in the pathogenetic conditions of AE.     

Covalent binding of chemicals to plant cuticles: Quantitative determination of epoxide contents of cutins

The epoxy groups contained in the cuticles of some plant species covalently bind residues of chemicals having a carboxyl function. This may lead to an increased persistence of these compounds in the environment. In order to assess the ecotoxicological potential of this reaction, an analytical method for the determination of cuticular epoxides was developed. Stable derivatives can be quantitatively formed by treating cuticles with 0.2M HC1 in 1,4-dioxane. This reaction leads to the formation of the corresponding chlorohydrins. It proceeds rapidly and without side-effects both in isolated cuticles andin situ. The derivatives can be analyzed by standard thin-layer and capillary gas Chromatographic methods. Electron impact and chemical ionization mass spectrometry was used to identify the chlorohydrins derived fromClivia andFicus leaf cutin.