Within-tree spatial variation in the leaf monoterpenes of Sequoia sempervirens

Location within a tree was analyzed as a source of variation in Sequoia sempervirens leaf monoterpenes. No differences were found for quantitative composition or total yield/dry wt among lower, middle and upper canopy positions. The awlshaped, spirally arranged leaves of vigorous upper shoots showed small quantitative compositional differences, but not differences in total yield. The intermediate leaf form of young sprouts had the most different monoterpene quantitative composition and about three times the total yield of the above two leaf forms. Analysis of a clonal ring of 17 adult trees resulted in coefficients of variation similar to those for samples collected from different canopy levels of the same shoot. Results revealed the sources and magnitudes of experimental error in comparative studies of this species' leaf monoterpenes, and did not support the concept that somatic mutation provides an important source of variation in a large, long-lived organism such as coast redwood.     

Alterations in high-affinity binding characteristics and levels of opioids in invertebrate ganglia during aging: Evidence for an opioid compensatory mechanism

In Mytilus and Leucophaea the high-affinity binding site density is significantly lower in old animals than in young animals, whereas the low-affinity site density remains unchanged. In Mytilus the estimated met-enkephalin and met-enkephalin-Arg6-Phe7 levels are significantly higher in old than in young animals. In Leucophaea only the met-enkephalin level can be determined, and it is also higher in old animals. The decrease in the high-affinity binding site density and the corresponding increase in endogenous enkephalin levels suggest the existence of an opioid compensatory mechanism associated with the aging process. In Mytilus there is a demonstrated decrease with age in intraganglionic dopamine levels in response to applied opiates. In addition, the inhibition of dopamine-stimulated adenylate cyclase activity by opiates also decreases in older animals. In Leucophaea the sex difference in opioid binding densities diminishes with age.     

Synthesis of fibronectin in normal and osteoarthritic articular cartilage

The content and the biosynthesis of fibronectin was examined in disease-free articular cartilage and in articular cartilage from osteoarthritic canine joints. Fibronectin content was increased in extracts of cartilage from osteoarthritic joints. Incubation of cartilage in vitro with [³H]phenylalanine and subsequent isolation of [³H]fibronectin from a gelatin affinity column and characterization by SDS-polyacrylamide gel electrophoresis and by immunoprecipitation indicated that disease-free and osteoarthritic cartilage explants synthesized fibronectin. About 50% of the [³H]fibronectin was recovered in the incubation medium. The osteoarthritic cartilage synthesized and accumulated up to 5-fold more [³H]fibronectin than disease-free cartilage.     

Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) parasitizing terrestrial isopods (Isopoda: Oniscoidea)

Summary A new mermithid nematode, Thaumamermis cosgrovei n. gen., n. sp. (Mermithidae: Nematoda) was found parasitizing two terrestrial isopods (Isopoda: Oniscoidea) in California. The hosts, Armadillidium vulgare (Latr.) (a pillbug) and Porcellio scaber (Latr.) (a sowbug) represent the first cases of isopods attacked by mermithid nematodes. The genus Thaumamermis can be distinguished from all previously described mermithids by the extremely dimorphic spicules, one being short and broad and the other long and filiform. It has been discovered that the nematodes are infected with an iridiovirus which commonly destroys the isopod hosts. ac]19800917     

Block by phencyclidine of acetylcholine and barium induced adrenal catecholamine secretion

Activation of the sympathetic system by phencyclidine (PCP) should result in catecholamine release from the adrenals. However, adrenalectomy does not reduce PCP-induced hypertension. In an attempt to rectify this inconsistency, the direct effects of PCP on the bovine adrenal medulla were examined. At (3×10^?6M), PCP reduced the acetylcholine-(ACh)-induced catecholamine release by 50%. Surprisingly, barium-induced secretion of catecholamines was also reduced by PCP. ACh-induced catecholamine release was not altered by 10^?3M 4-aminopyridine (4 AP), the potassium channel blocker. Thus, calcium antagonist actions of PCP and consequent block of catecholamine secretion from adrenal medulla may explain the lack of effect of adrenalectomy on PCP-induced hypertension. Possible contributions of calcium and/or potassium channel blockade to other manifestations of PCP overdosage are discussed.     

Is group progressive relaxation training as effective with hyperactive children as individual EMG biofeedback treatment?

This study examined whether group progressive relaxation training was as effective as individual EMG biofeedback training in facilitating the academic achievement and self-control of 45 hyperactive elementary school children. Academic achievement was assessed with the Gates-MacGinities Reading Tests, and self-control was measured with the Nowicki-Strickland and the Teacher Rating scales. Eight sessions were scheduled at weekly intervals. Progressive relaxation was conducted in groups of seven or eight and was induced with a commercial audiocassette program. EMG training augmented frontalis biofeedback with those taped exercises. A placebo group listened to taped children's stories. Multivariate analysis of variance indicated no significant differences among the three contrast groups when all dependent variables were considered together. However, univariate F values and discriminant analysis disclosed locus of control to be significantly more internal for the progressive relaxation condition. Also, differences between the two relaxation and the placebo groups, though not statistically significant, were all in the expected direction. While the relative efficacy of group progressive relaxation could not be established conclusively, the data appeared sufficiently positive to warrant further investigation of this cost-effective prospective intervention.The opinions expressed by the authors are not necessarily those of their respective institutions.     

Normal thymic cortical epithelial cells developmentally regulate the expression of a B-lineage transformation-associated antigen

Nonlymphoid, stromal cells in the mouse thymus are believed to be important in T cell maturation and have been proposed to play a central role in the acquisition of major histocompatibility complex (MHC) restriction and self-tolerance by maturing thymocytes. Both cortical and medullary epithelial cells in the thymus express high levels of class II (A) major histocompatibility antigens (MHC Ags). We show here that a specific subset of these A^– epithelial cells express a transformation-associated antigen (6C3Ag) found previously on the surfaces of Abelson murine leukemia virus-transformed pre-B cells and on those bone marrow-derived stromal cell clones which support normal and preneoplastic pre-B cell proliferation. Among solid lymphoid organs, only the thymus contains 6C3Ag¹ cells and within the thymus, this antigen is found exclusively on A^– epithelial cells in cortical regions. It is striking that the expression of the 6C3Ag on thymic epithelium is developmentally regulated, suggesting a role for this lymphostromal antigen in the maturation of the thymic microenvironment.     

Interleukin-1-β and Tumor Necrosis Factor-α Increase Peripheral-Type Benzodiazepine Binding Sites in Cultured Polygonal Astrocytes

Peripheral-type benzodiazepine binding sites (PTBBS) are markedly increased in the injured CNS. Astrocytes appear to be the primary cell type which express increased PTBBS. Because certain cytokines within the injured CNS are potent mitogens for astrocytes, we examined the effects of two such cytokines, interleukin (IL)-1 beta and tumor necrosis factor (TNF), on PTBBS in cultured astrocytes using [3H]Ro 5-4864 as the specific ligand. Purified cultures of either polygonal or process-bearing astrocytes were prepared from neonatal rat cerebral hemispheres. At a concentration of 1.8 nM, specific binding of the radioactive ligand to polygonal astrocytes reached equilibrium within 60 min and was half-maximal by 5-10 min. By contrast, specific binding to process-bearing astrocytes barely exceeded background levels. IL-1 and TNF increased PTBBS within polygonal astrocytes in both dose- and time-dependent manners. At 10-50 ng/ml, IL-1 beta and TNF-alpha elevated [3H]Ro 5-4864 binding in polygonal astrocyte cultures 65 and 87%, respectively, above the level in control cultures. However, no changes in PTBBS were seen within polygonal astrocytes after IL-2 treatment. Scatchard analysis of saturation binding experiments suggested that the increase in PTBBS promoted by TNF was due to an increased number of binding sites present in polygonal astrocytes and not due to an increase in receptor affinity. Binding data suggested that PTBBS within cultures of process-bearing astrocytes were virtually absent irrespective of the treatment. These in vitro data suggest that certain cytokines found in the injured brain may be involved in up-regulating PTBBS within a particular subtype of astrocyte.