FEASIBILITY OF CONDUCTING CARDIOVASCULAR OUTCOME RESEARCH IN AUSTRALIAN GENERAL PRACTICE: RESULTS FROM THE ANBP2 PILOT STUDY

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.     

Differential role of the vagus in diurnal gene expression rhythms in the small intestine

The objective of this study was to examine the function of vagal innervation in maintaining diurnal rhythmicity in the expression of intestinal absorptive genes. Rats underwent truncal vagotomy and were maintained for 7 days on nighttime scheduled feeding (12-h light/12-h dark cycle). Vagotomized rats (V; n = 9) were pair-fed with sham-operated controls (S; n = 4). Unoperated normal rats (N; n = 6) were also included as controls. Half the rats were killed 3 h after lights on (ZT3; Zeitgeber Time, with lights-on considered ZT0) and the other half at ZT9, the time interval over which we have previously shown that sucrase and sugar transporter expression exhibits a significant anticipatory increase. RNA and protein extracted from mucosa of proximal jejunums were subjected to Northern and Western blot analyses to assess the increase in gene expression. Sham operation did not alter the normal diurnal rhythmicity of intestinal gene expression. Control rats (S plus N) exhibited the expected increase in RNA levels at ZT9 versus ZT3 for SGLT1 (4.5-fold), GLUT2 (5.3-fold), GLUT5 (4.1-fold), and sucrase (2.9-fold; P > 0.001 in all cases). In contrast, the induction in V rats was markedly blunted for GLUT2 (1.3-fold) and sucrase (1.5-fold) but not for SGLT1 (5.0-fold) or GLUT5 (4.2-fold). The mRNA levels for GLUT2 and sucrase at ZT9 were significantly lower in V rats versus controls (P < 0.001). GLUT2 and SGLT1 protein levels exhibited a parallel pattern: SGLT1 induction was 4.3-fold in control rats (P < 0.01) and 3.8-fold in V rats (P <0.01), whereas GLUT2 induction was 3.3-fold in control rats (P < 0.01) but only 1.4-fold in V rats (NS). Our results indicate that signaling through the vagus nerve is necessary to maintain the anticipatory induction pattern of GLUT2 and sucrase. The persistent rhythm in both SGLT1 and GLUT5 indicates that (1) diurnal induction of these genes is independent of vagal innervation and (2) the procedure did not cause an overall loss of intestinal function. Thus, entrainment of anticipatory diurnal gene expression in the intestine occurs via two separate pathways that are differentially dependent on vagal input.     

Astrocyte RNA in relation to neuronal RNA depletion in Alzheimer's disease

Summary A new double-staining procedure, in which the techniques of immunocytochemistry of glial fibrillary acidic protein (GFAP) and quantitative microdensitometry of azure B-RNA were combined, was used to study nucleic acid alterations in fibrous astrocytes in Alzheimer's disease (AD). RNA contents of GFAP-positive cells of the hippocampal endplate (Rose's H₃-H₅ fields) and the dentate gyrus molecular layer were determined in ten autopsy-proven AD patients (ages 51–88) and ten age-matched, non-demented control. In addition, RNA contents of pyramidal neurons of the endplate were examined. While there were no differences in RNA contents of astrocytes of either region between AD patients and controls, neuronal RNA was markedly depleted. These data suggest that astrocytes maintain protein synthetic capabilities in AD and that RNA loss is limited to the neuronal compartment.Supported by Grants 1P01-AG05119 and 1P50-AG05144 from the National Institutes of Health and by a Small Research Project Award from the University of Kentucky Medical Center     

Decreasing the level of translation initiation factor 4E with antisense rna causes reversal of ras-mediated transformation and tumorigenesis of cloned rat embryo fibroblasts

Transformation of cloned rat embryo fibroblasts (CREF) with the T24-ras oncogene results in loss of contact inhibition, growth in soft agar and tumor formation in nude mice. Previously we showed that in such cells (CREF T24), the phosphorylation rate of protein synthesis initiation factor 4E (elF-4E) is increased, correlating with an increase in the general rate of protein synthesis. In the present study, we have expressed antisense RNA complementary to elF-4E mRNA in CREF T24 cells using a stably integrated vector. Cells expressing antisense RNA (CREF T24/AS) contained 30-50% of the normal level of elF-4E and exhibited many of the properties of untransformed cells. CREF T24 had a spindle-shaped, refractile appearance, whereas CREF T24/AS grew in ordered, parallel patterns and exhibited contact inhibition similar to untransformed CREF. The rates of growth and protein synthesis in CREF T24/AS were decreased compared to CREF T24 but were not as low as in CREF. The efficiency of growth in soft agar was 11-fold lower for CREF T24/AS compared with CREF T24. The latency period for tumor formation in nude mice was increased from 8 days for CREF T24 to 17-27 days for CREF T24/AS and various clonal lines derived from them. Cell lines established from these CREF T24/AS-derived tumors were shown to have partially regained the elF-4E levels characteristic of CREF T24. These results demonstrate that many of the phenotypic alterations associated with ras-induced malignant transformation can be reversed by a moderate reduction of the translational initiation capacity and therefore may be mediated through a translational mechanism.