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 Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy.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.     

Left ventricular filling: relationship with arterial blood pressure, left ventricular mass, age, heart rate and body build.

The relationships of age, heart rate, body build and, in particular, of arterial blood pressure and left ventricular mass to several Doppler indexes of diastolic function were evaluated in a series of 80 subjects with a wide range of blood pressure levels (106-217/68-144 mmHg). Body build and age results were inversely correlated to the indexes, reflecting the early contribution to left ventricular filling, whereas the increase in heart rate was associated with an increase in late diastolic contribution. Strong correlations (in most instances, P less than 0.0001) were observed with arterial blood pressure and left ventricular mass: the increase of these parameters was associated with a decrease of early transmitral peak velocity (E peak) and of early filling fraction, with an increase of late diastolic transmitral peak velocity (A peak) and of A:E ratio and, finally, with an increase of both deceleration time of E peak and acceleration time to A peak. Blood pressure or left ventricular mass were also confirmed as strong predictors of nearly all the Doppler-derived diastolic indexes by stepwise multiple regression analysis. When the subjects were subdivided into quintiles according to diastolic blood pressure and the average values of the five subgroups were compared, age, heart rate and body build results were similar in the quintiles while diastolic blood pressure increased stepwise by 10 mmHg. Analysis of variance showed significant differences for all the indexes of left ventricular filling except deceleration time of and acceleration time to E peak (P less than 0.05 to P less than 0.0001) and almost all the echo-Doppler indexes showed a linear trend with diastolic blood pressure and left ventricular mass.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hemodynamic reserve in carotid surgery and the use of "superselective" shunt]

The aim of this study is to establish whether a preoperative evaluation of the Cerebral Hemodynamic Reserve, carried out by means of transcranial Doppler and SPECT with provocative test (acetazolamide) can single out those patients who, because they are supplied with a poor cerebral reserve, are truly in need of intraoperative shunting after carotid clamping. All patients were intraoperatively monitored by means of Somato Sensitive Evoked Potentials (SSEPs). Those patients who were shunted due to abnormalities in SSEPs were also those who showed a perfusion and velocity increase below 15%, and therefore supplied, in our opinion, with a scanty cerebral reserve. No, but one, neurological deficit appeared on awakening in patients who were not shunted.     

Urea rebound and delivered Kt/V determination with a continuous urea sensor

BACKGROUND: The recent introduction of urea sensors for dialysis monitoring has made possible new approaches to urea kinetic modelling. In this study we show how the equilibrated postdialysis urea concentration (Ceq) and Kt/V corrected for double-pool urea kinetics (Kt/Vdp) can be accurately determined using an on-line sensor providing a continuous measure of blood water urea. A modification of the Smye constant volume double-pool theory led to the following equations for Ceq and Kt/Vdp [formula: see text] where Cpre is the blood concentration measured at the start of dialysis, t is the length of the dialysis session (in min) and S(ex) is the constant slope of the blood urea logarithm concentration decline following development of the intercompartmental urea concentration gradient in the first 30-60 min of dialysis. METHODS: These equations were tested in 11 patients undergoing 165-240 min of paired filtration dialysis with continuous monitoring of blood urea concentration. Cpre was determined as the plateau concentration during a preliminary period of 15-20 min of slow isolated ultrafiltration. S(ex) was accurately determined from linear regression applied to the urea sensor data from the 80-min point to the end of dialysis. RESULTS: Ceq and Kt/Vdp determined from the above equations compared closely to values determined from 25-40 min of urea rebound monitoring with the urea sensor: 10.6 +/- 3.0 versus 10.8 +/- 2.7 mmol/l (mean +/- SD) for Ceq and 1.21 +/- 0.24 versus 1.18 +/- 0.20 for Kt/Vdp, compared to single-pool values of Kt/V = 1.34 +/- 0.23. CONCLUSION: This technique may be readily programmed into on-line urea monitors to provide current and extrapolated values of Ceq and Kt/Vdp from about the first hour of dialysis.      

Small interfering RNA inhibits SARS-CoV nucleocapsid gene expression in cultured cells and mouse muscles

SARS-CoV isa newly identified coronavirus that causes severe acute respiratory syndrome （SARS）. Currently, there is no effective method available for prophylaxis and treatment of SARS-CoVinfections. In the present study, the influence of small interfering RNA （siRNA） on SARS-CoV nucleocapsid （N） protein expression was detected in cultured cells and mouse muscles. Four siRNA expression cassettes driven by mouse U6 promoter targeting SARS-CoV N gene were prepared, and their inhibitory effects on expression of N and enhanced green fluorescence protein （EGFP） fusion protein were observed.