Trophic effects of essential fatty acids on pig skin

The daily oral administration of 3 ml of two oils (So-5407 and So-1129) containing essential fatty acids (EFAs) for 16 weeks resulted in a transient increase in cell proliferative activity in the skin of female Large White pigs. The So-5407 oil contained 7% gamma-linolenic acid (GLA) whereas So-1129 was an oil of similar composition, but with no GLA. Hyperplasia of the epidermis was observed after the administration of both oils, and this was characterized by an increase in the size of the rete pegs. The maximum effect occurred at 4 weeks after the start of oil administration, at which time the number of viable cell layers had increased by a factor of approximately 1.5, and mean epidermal thickness (excluding the stratum corneum) was approximately 40% greater than that of the epidermis prior to oil administration. There was a marked increase in the labelling index (LI) of the basal cell layer of the epidermis in pigs receiving So-5407. Maximum LIs were quantified at 4 weeks after the start of administration and were 18.8 ± 1.3% and 13.1 ± 1.7% for pigs receiving So-5407 and So-1129, respectively. After this time the LI declined prgressively and had returned to values within normal limits (P>0.1) by 8 weeks after the start of administration of both oils. A similar pattern of change in the LI was seen in the follicular epithelium, although the peak values at 4 weeks after the start of oil administration of 12.2 ± 1.8% and 10.8 ± 0.9 for the groups receiving So-5407 and So-1129, respectively, were lower than in the epidermis. Labelled cells were also counted in the papillary dermis and maximum values were again seen at 4 weeks after the start of oil administration. Of the two oils, So-1129 had the greatest effect, with the number of labelled cells in the papillary dermis being a factor of three to four-fold higher than in skin prior to oil administration, between 2 and 12 weeks after the start of administration.     

Relationship between levels of nerve growth factor (NGF) and its messenger RNA in sympathetic ganglia and peripheral target tissues.

We have developed a sensitive assay for the quantification of nerve growth factor mRNA (mRNANGF) in various tissues of the mouse using in vitro transcribed RNANGF. Probes of both polarities were used to determine the specificity of the hybridization signals obtained. Comparison of NGF levels with its mRNA revealed that both were correlated with the density of sympathetic innervation. Thus, vas deferens contained high levels of both NGF and mRNANGF, whereas skeletal muscle levels were barely detectable, indicating that in peripheral tissues NGF levels are primarily regulated by the quantity of mRNANGF and not by the rate of processing of NGF precursor to NGF. However, although superior cervical ganglia contained the highest levels of NGF, its mRNA was barely detectable. Thus, the high levels of NGF in sympathetic ganglia result from retrograde axonal transport rather than local synthesis. The quantity of NGF found in the submandibular glands of female animals was three orders of magnitude higher than expected from their mRNA levels. This observation is discussed in the context of the difference between the mechanism of storage and exocytosis of exocrine glands versus the constitutive release from other tissues.     

The nature of the trifluoperazine binding sites on calmodulin and troponin-C

We have employed 1H-nuclear magnetic resonance spectroscopy to study the interaction of the drug trifluoperazine with calmodulin and troponin-C. Distinct trifluoperazine-binding sites exist in the N- and C-terminal halves of both proteins. Each site consists of a group of hydrophobic side-chains brought into proximity by the Ca2+-dependent juxtaposition of two alpha-helical segments of the protein, each, in turn, belonging to a different Ca2+-binding site in the protein half. The trifluoperazine-induced inhibition of the biological activating ability of calmodulin appears to result from conformational restrictions conferred upon the protein by the bound drug.     

The muscle layer of the canine gallbladder and cystic duct

The muscle layer of the canine gallbladder wall and cystic duct was found to be a three-dimensional meshwork of smooth muscle bundles which appear loosely and irregularly arranged on the mucosal aspect and consolidate to form a homogeneous plate-like layer on the serosal aspect. The muscle bundles are tightly woven around interspersed pockets of loose connective tissue in the gallbladder wall and gradually become loosely arranged with more prominent amounts of intervening connective tissue in the cystic duct. The muscle layer is thickest in the gallbladder wall and becomes progressively thinner out into the cystic duct. No anatomic sphincter was observed. Ultrastructural organization revealed individual muscle fibers to be of irregular profile, often branching, widely spaced with intervening collagen fibers, and having few cell-to-cell contacts.     

Role of Chlamydia trachomatis and HLA-B27 in sexually acquired reactive arthritis.

Inflammatory arthritis, tendinitis, and fasciitis after non-specific urethritis ("sexually acquired reactive arthritis" (SARA)) was studied prospectively in 531 men with non-specific urethritis, with particular reference to the frequency of isolation of Chlamydia trachomatis and the presence of HLA-B27. Satisfactory cultures were obtained from the urethral swabs from 384 patients; and HLA typing was performed on 482, of whom 30 (6%) were HLA-B27-positive. Arthritis developed in 16 patients, and five of the 14 (36%) with satisfactory cultures were positive for C trachomatis; 135 of the patients without arthritis were also positive for C trachomatis, an identical proportion. Seven of the 15 patients (40%) with arthritis who were HLA-typed were HLA-B27-positive. Six of the 30 patients with HLA-B27 developed peripheral arthritis in contrast to only nine of the 452 patients lacking the antigen, suggesting a tenfold increase susceptibility. C trachomatis, however, was no more prevalent in cultures from HLA-B27-positive men than from the others. Thus carriage of C trachomatis is unlikely to be influenced by HLA-B27. C trachomatis may be an important pathogen in some cases of SARA but does not appear to be an exclusive trigger factor for this condition.