Occurrence and Distribution of Lactate Dehydrogenase in Knee Joint Carilage in Healthy and Osteoarthrotic Dogs

According to clinical studies, degenerative diseases of canine joints lead to higher lactate dehydrogenase (LDH) levels in synovial fluid. The goal of the present study was to examine the intraarticular distribution of LDH in healthy and osteoarthrotic knee joints in order to identify possible sources of LDH in synovial fluid. As synovial LDH concentrations neither correlate with the number of leukocytes nor with synovitis, our investigation focused on the articular cartilage. Samples from healthy and osteoarthrotic knee joints were fixed and processed for transmission electron microscopy (TEM), immunohistochemistry (IHC), and immunocytochemistry (ICC). In addition, fresh cartilage samples were investigated cytochemically by the tetrazolium‐formazan reaction. Analyses of blood and synovial fluid samples were used to confirm the absence of inflammatory disease. Morphology of articular cartilage was assessed macroscopically and by means of TEM. IHC revealed highest levels of LDH in chondrones and a diffuse labelling of the matrix with a distinctive decrease in signal from superficial to deeper cartilage layers. Ultrastructural localization by ICC showed LDH to be present in the cytoplasm of all chondrocytes and confirmed the density gradient in the matrix. Labelling was absent from nuclei and from pericellular rims. Cytochemistry confirmed the distribution pattern and, thus, expanded our findings beyond immunological evidence by providing proof of enzymatic activity of LDH in articular cartilage. The present results indicate that LDH is transferred from chondrocytes to the cartilaginous matrix. We suggest, therefore, that LDH found in synovial fluid originates from the articular cartilage and that osteoarthrotic processes promote LDH release from the cartilaginous matrix.     

Anatomical Atlas of the Quail's Ear (Coturnix coturnix)

This study aims to enhance the anatomical knowledge of the ear of the adult quail (Coturnix coturnix) through the creation of a scaled 3D model utilizing data from micro‐CT images. In addition, 17 annotated histological sections of the quail's ear are aligned to their 3D position in the model. The resulting anatomical atlas provides an intuitive insight into the 3D anatomy and can be used for medical education. The model also allows measuring anatomical structures and can thus serve as reference for the quail's auricular anatomy and as a basis to evaluate clinical diagnostic imaging results.     

Exposure of rainbow trout (Oncorhynchus mykiss) to nonylphenol is associated with an increased chloride cell fractional surface area

Nonylphenol is a biodegradation product of a widely used group of non-ionic detergents. Because of its ubiquitous distribution and persistence, nonylphenol is present in surface waters as a pollutant. Little is known about its biological effects at environmentally relevant concentrations other than its action as a xenoestrogen. The goal of the present paper was to study the trout gill surface epithelium as the major interface between fish and water in view of possible morphological alterations due to exposure to nonylphenol. Rainbow trout were intermittently exposed to 10 micrograms/l nonylphenol and gill samples from experimental and control animals were investigated by scanning electron microscopy. Gill surface epithelium was scrutinised for changes in chloride cell density and their status regarding cell surface modifications. In addition, chloride cell fractional surface area (CCFA) was determined by morphometrical methods. Statistical analysis revealed a highly significant increase of CCFA in animals exposed to nonylphenol as compared to control animals (P = 0.0001). Semi-quantitative assessment of the other parameters suggested a higher chloride cell density and a larger proportion of chloride cells bearing microvilli. Taken together, these results provide evidence that exposure of trout to nonylphenol is associated with a substantial increase in the active interface of chloride cells with water. We interpret these findings as being a means to further the fish's capacity for calcium exchange.     

The Glandular Chambers of the Placenta of the Bitch in the Second Third of Pregnancy (day 30–44): An Ultrastructural, Ultrahistochemical and Lectinhistochemical Investigation

The present study represents the first comprehensive investigation of the glandular chambers of the placenta of the bitch. We examined the glandular chambers by SEM, TEM, ultrahistochemical and lectinhistochemical methods. The glandular epithelium is a high columnar epithelium with club-shaped apical protrusions bearing short microvilli. The epithelium forms extensive folds which fill up most of the lumen of the glandular chambers. Proceeding to the placental labyrinth, the glandular chambers are covered by the tips of the chorionic tufts. The trophoblast and the glandular epithelium are separated by a thick layer of secretions. The ultrastructure cytology of the columnar epithelium is characterized by several Golgi complexes and abundant apical-located mucus vesicles with a positive dialysed iron reaction. Lectin histochemistry reveals in general a strong reaction of these mucus vesicles with all lectins used. The mucus in the lumen of the glandular chamber reacts strongly with WGA. NeuWGA, LPA and ConA. The trophoblastic villi projecting into the lumen of the glandular chambers are covered by a pseudostratified epithelium consisting of a flat basal layer and a superficial columnar one. Its cytoplasm is filled with large fusing vacuoles containing longish screw-shaped structures. No morphological equivalent of absorption is found. According to the ultrastructure of the trophoblast, the significance of the mucus in the glandular chambers in stopping the invasive growth of the trophoblast is discussed.     

Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase

A thermostable DNA polymerase was used in an in vitro DNA amplification procedure, the polymerase chain reaction. The enzyme, isolated from Thermus aquaticus, greatly simplifies the procedure and, by enabling the amplification reaction to be performed at higher temperatures, significantly improves the specificity, yield, sensitivity, and length of products that can be amplified. Single-copy genomic sequences were amplified by a factor of more than 10 million with very high specificity, and DNA segments up to 2000 base pairs were readily amplified. In addition, the method was used to amplify and detect a target DNA molecule present only once in a sample of 10(5) cells.     

Observations of the periodontal ligament and cementum in cats with dental resorptive lesions

The etiology of feline dental resorptive lesions is unknown, but some evidence suggests that interactions between components of the periodontium may be initiating factors in the development of these lesions. In the present study, 22 clinically normal teeth were harvested from 7 cats. The teeth and periodontium were radiographed and examined histologically. In addition, 14 of the 22 teeth were examined histometrically. Two teeth were histologically normal with an open apical foramen and two were normal with a closed apical foramen. Histological evidence of periodontal ligament degeneration without cementum resorption was observed in 8 teeth, and varying degrees of cementum resorption were observed in 10 teeth. Mandibular molar and premolar teeth had distal drift, and mandibular canine teeth had mesial drift. Alterations in the periodontal ligament may represent a preclinical stage of dental resorption.     

Distribution of muscarinic receptor subtypes and interstitial cells of Cajal in the gastrointestinal tract of healthy dairy cows

OBJECTIVE: To describe the distribution of muscarinic receptor subtypes M(1) to M(5) and interstitial cells of Cajal (ICCs) in the gastrointestinal tract of healthy dairy cows. SAMPLE POPULATION: Full-thickness samples were collected from the fundus, corpus, and pyloric part of the abomasum and from the duodenum, ileum, cecum, proximal loop of the ascending colon, and both external loops of the spiral colon of 5 healthy dairy cows after slaughter. PROCEDURES: Samples were fixed in paraformaldehyde and embedded in paraffin. Muscarinic receptor subtypes and ICCs were identified by immunohistochemical analysis. RESULTS: Staining for M(1) receptors was found in the submucosal plexus and myenteric plexus. Antibodies against M(2) receptors stained nuclei of smooth muscle cells only. Evidence of M(3) receptors was found in the lamina propria, in intramuscular neuronal terminals, on intermuscular nerve fibers, and on myocytes of microvessels. There was no staining for M(4) receptors. Staining for M(5) receptors was evident in the myocytes of microvessels and in smooth muscle cells. The ICCs were detected in the myenteric plexus and within smooth muscle layers. Distribution among locations of the bovine gastrointestinal tract did not differ for muscarinic receptor subtypes or ICCs. CONCLUSIONS AND CLINICAL RELEVANCE: The broad distribution of M(1), M(3), M(5), and ICCs in the bovine gastrointestinal tract indicated that these components are likely to play an important role in the regulation of gastrointestinal tract motility in healthy dairy cows. Muscarinic receptors and ICCs may be implicated in the pathogenesis of motility disorders, such as abomasal displacement and cecal dilatation-dislocation.     

Fresh-stem bending of silver fir and Norway spruce

The bending and growth characteristics of large fresh stems from four silver fir (Abies alba Mill.) and three Norway spruce (Picea abies (L.) Karst.) trees were studied. Twenty logs taken from different stem heights were subjected to four-point bending tests. From the bending test records, we calculated stress-strain curves, which accounted for detailed log taper, shear deformation and self weight. From these curves we determined, among other parameters, the modulus of elasticity (MOE), the modulus of rupture (MOR) and the work absorbed in bending (W). No significant differences were found between species for the wood properties examined. Values of MOE, MOR and W generally decreased with stem height, with MOR in the range of 43 to 59 MPa and MOE ranging from 10.6 to 15.6 GPa. These MOE values are twice or more those reported for stems of young Sitka spruce (Picea sitchensis (Bong.) Carr.) trees. Based on the radial growth properties measured in discs from the logs, we calculated predicted values of MOE and MOR for the stem cross section. The predictions of MOE were precise, whereas those of MOR were approximate because of a complex combination of different failure mechanisms. Methods to test and calculate MOE, MOR and W for the stems of living trees are discussed with the aim of improving analyses of tree biomechanics and assessments of forest stability protection.     

Rockfall and snow avalanche impacts leave different anatomical signatures in tree rings of juvenile Larix decidua

Rockfall and snow avalanche events often cause injury to European larch (Larix decidua Mill.) trees, giving rise to the formation of callus tissue and tangential rows of traumatic resin ducts (TRDs). We analyzed and quantified anatomical reactions of juvenile trees injured before the start of the growing season by snow avalanches (15 trees, 324 cross sections) or rockfalls (18 trees, 270 cross sections). Traumatic resin ducts were observed in the growth ring formed following injury in 94.3% of the rockfall samples and 87.3% of the snow avalanche samples. Traumatic resin ducts were formed at the beginning of the new annual ring around wounds caused by rockfalls. In contrast, in trees injured by snow avalanches, TRDs were not formed until after the formation of several rows of early earlywood (EE) tracheids (mean +/- SD = 4.19 +/- 2.56 rows). The dimensions of the EE tracheids observed in the snow avalanche samples were greatly reduced in the tissues bordering the wound, with radial width reaching an average of only 50% and lumen cross-sectional area an average of only 46% of pre-event values. It is therefore possible to differentiate injuries due to past snow avalanches from injuries due to rockfall based on anatomical growth reactions in the tissues bordering scars.