Localization of the Miller-Dieker critical region is proximal to locus D17S34 (p144D6) in 17p13.3

A child with normal growth and development and the abnormal karyotype 46,XY,17ps, was analyzed using molecular probes localized to 17p13. The results indicated the presence of two copies of the probes YNZ22.1 (D17S5) and YNH37.3 (D17S28), previously shown to be deleted in all Miller-Dieker (MDS) patients studied. However, the patient was hemizygous for probe p144D6 (D17S34), which is absent in approximately 75% of the MDS patients. As the patient is active at 9 months of age, with no clinical signs of MDS, the results confirm that the absence of locus D17S34 does not lead to the phenotypic expression of MDS. Furthermore, this deletion should assist in defining the distal limits of this contiguous gene syndrome.     

Ligand-receptor interactions involved in the stimulation of Swiss 3T3 fibroblasts by insulin-like growth factors and insulin.

1. The binding of 125I-labelled insulin-like growth factor 1 (125I-IGF-1) to Swiss mouse 3T3 fibroblasts was time- and concentration-dependent. Unlabelled IGF-1 had a slightly higher potency than multiplication-stimulating activity (MSA) in inhibiting the binding of 125I-IGF-1, and insulin gave a parallel inhibition curve at 300-1000-fold lower potency. Chemical cross-linking of bound 125I-IGF-1 to its receptors, followed by polyacrylamide-gel electrophoresis under reducing conditions, revealed a major band of Mr 130,000, the labelling of which was inhibited by IGF-1 or high concentrations of insulin. 2. The binding of 125I-IGF-1 was not affected by either co-incubation or preincubation of the cells with a range of heterologous growth factors and mitogens. However, IGF-1 and MSA each induced down-regulation of 125I-IGF-1 binding sites. 3. The maximal stimulations of DNA synthesis induced by IGF-1, MSA and insulin, in the presence of a synergizing mitogen, were similar. The dose-response curve for insulin was not parallel to those for IGF-1 and MSA; in particular, low concentrations of insulin induced a greater stimulation than expected on the basis of its potency in the inhibition or down-regulation of 125I-IGF-1 binding. 4. The preincubation of 125I-IGF-1 with Swiss 3T3 cells at 37 degrees C decreased its ability to bind to a second batch of cells. This inactivation did not occur when the preincubation was performed at 4 degrees C or in the presence of cycloheximide. Chemical cross-linking revealed that the cells released an IGF-binding protein, giving a complex of Mr about 48,000. 5. It is concluded that type I IGF receptors mediate the stimulation of Swiss 3T3 cells by insulin-like mitogens, but that insulin probably stimulates the cells through insulin receptors. The cells can modulate the amount of ligand binding, both by down-regulation of the receptors and by the secretion of an IGF-binding protein.     

Dexamethasone influences the lipid fluidity, lipid composition and glycosphingolipid glycosyltransferase activities of rat proximal-small-intestinal Golgi membranes.

Experiments were performed to examine the effects of subcutaneous administration of the synthetic glucocorticoid dexamethasone (100 micrograms/day per 100 g body wt.) on the lipid fluidity, lipid composition and glycosphingolipid glycosyltransferase activities of rat proximal-small-intestinal Golgi membranes. After 4 days of treatment, Golgi membranes and liposomes prepared from treated rats were found to possess a greater fluidity than their control (diluent or 0.9% NaCl) counterpart, as assessed by steady-state fluorescence-polarization techniques using three different fluorophores. Moreover, analysis of the effects of temperature on the anisotropy values of 1,6-diphenylhexa-1,3,5-triene, using Arrhenius plots, demonstrated that the mean break-point temperatures of treated preparations were 4-5 degrees C lower than those of control preparations. Changes in the fatty acyl saturation index and double-bond index of treated membranes, secondary to alterations in stearic acid, linoleic acid and arachidonic acid, at least in part, appeared to be responsible for the differences in fluidity noted between treated and control Golgi membranes. Concomitant with these fluidity and lipid-compositional alterations, treated membranes possessed higher specific activities of UDP-galactosyl-lactosylceramide galactosyltransferase and CMP-N-acetylneuraminic acid:lactosylceramide sialyltransferase than their control counterparts. Experiments utilizing benzyl alcohol, a known fluidizer, furthermore suggested that the fluidity alteration induced by dexamethasone may be responsible for the increased activity of the former, but not the latter, glycosphingolipid glycosyltransferase.     

Evolutionary conservation of the human homologue of the yeast cell cycle control gene cdc2 and assignment of Cd2 to chromosome 10

Summary The human homologue of the fission yeast Schizosaccharomyces pombe cell cycle control gene cdc2 has been assigned to chromosome 10. DNA hybridization reveals that this gene is highly conserved in vertebrates. The human CDC2 gene probe detects a simple two-allele polymorphism in Taq1-digested DNA.     

Endogenous lipid pneumonia in opossums from Louisiana

Endogenous lipid pneumonia was present in 19 of 27 opossums (Didelphis virginiana) trapped in the vicinity of Baton Rouge, Louisiana. The severity of lesions varied from small pleural and subpleural aggregates of foamy macrophages with minimal disruption of pulmonary architecture to large nodular accumulations of foam cells with cholesterol clefts and localized emphysema. The cause of the lipid pneumonia may be related to pulmonary nematode parasite infections, which were evident in 13 of the affected animals.     

Peptide injections into the amygdala of conscious rats: effects on blood pressure, heart rate and plasma catecholamines

The central nucleus of the amygdala (Ce) mediates cardiovascular and autonomic changes associated with defense or fear responses. At least 16 different neuropeptides have been identified within nerve terminals within the Ce. The role that these peptides play in the Ce regulation of cardiovascular and autonomic function has been assessed. Neuropeptides were microinjected into the region of the Ce and mean arterial pressure (MAP), heart rate (HR) and plasma catecholamine concentrations were measured. Five of the 16 peptides caused changes of MAP and HR. Thyrotropin releasing factor (TRF) and calcitonin gene-related peptide (CGRP) induced increases of MAP and HR. Angiotensin-II (A-II) and somatostatin-28 (SS-28) injection produced increases of MAP and decreases of HR. Bombesin (Bom) injections into the Ce induced an increase of MAP but did not alter HR. Corticotropin releasing factor (CRF), TRF and CGRP were the only peptides found to increase plasma catecholamine concentrations. These results support the conclusion that the Ce contains several peptides that could be involved in the regulation of cardiovascular and autonomic nervous system function. A role of the amygdala in mediating the observed effects of CRF, TRF, CGRP, A-II, SS-28, and Bom is suggested by these studies.     

Modulation of lymphocyte nuclear matrix organization in vivo by 5,6-dichloro-1-beta-D-ribofuranosyl benzimidazole: an autoradiographic and immunofluorescence study

Assembly of active nuclei in lymphocytes stimulated by mitogen is paralleled by the elaboration of a structurally and biochemically complex nuclear matrix (NM). To examine the dynamics of individual NM polypeptide components during blastogenesis, we have applied immunofluorescence labelling with anti-NM antibodies to concanavalin A-stimulated mouse splenocytes. Whereas peripherin and PI2 antigens did not reorganize during stimulation, labelling of PI1 and small nuclear ribonucleoprotein (snRNP) antigens increased markedly in intensity and redistributed in concert with the previously reported NM restructuring. Double-labelling showed, furthermore, that snRNPs and the internal staining component of PI1 were largely co-localized. As an approach to studying the role of RNA and RNA synthesis in NM organization, we have further examined the effects of the inhibitor of RNA synthesis, 5,6-dichloro-1-beta-D-ribofuranosyl benzimidazole (DRB), on NM antigen distribution. The rapid inhibition of 3H-uridine incorporation by DRB was accompanied by coordinate aggregation of snRNPs and of the internal PI1 component into large, brightly stained patches. Both 3H-uridine incorporation levels and antigen localization were readily reversed upon removal of DRB. We conclude that NM antigens behave independently during nuclear and NM assembly and that NM organization, as reflected by NM antigen distribution, is modulated by con A- and DRB-induced alterations in RNA synthesis. We propose, furthermore, that the PI1 antigen plays a role in RNA metabolism, and is possibly involved in RNA transport to the nuclear periphery.     

Field Evaluation of Steinernema feltiae Against the Web-spinning Larch Sawfly Cephalcia lariciphila

Field trials were conducted in Rheola Forest, Wales, Great Britain, to determine the effectiveness of Steinernema feltiae UK strain in controlling the web-spinning larch sawfly Cephalcia lariciphila. Foliar sprays at the rate of 5,000-20,000 nematodes/100 cm branch resulted in 3.4-29.4% infection of sawfly larvae. Soil application of 200 nematodes/cm² resulted in 61% infection of sawfly prepupae and 17.3% of pupae. Prepupal infection ranged from 4.8 to 14.7% 1 year after nematode application. Soil applications of this nematode show that it has potential for biological control of sawfly prepupae.