Clinical Evaluation of Atrial Synchronous Ventricular Inhibited Pacemakers

The technical specifications and the operation of two atrial synchronous ventricular inhibited (ASVIP) pacemaker designs are described along with the results of clinical evaluation of these pacemakers in 30 patients. Clinical advantages of such pacemakers are contrasted with the performance of A-V sequential (DVI) and atrial synchronous (VAT) systems.     

The mechanism of white cell reduction by synthetic fiber cell filters

The mechanism of white cell (WBC) retention by synthetic fiber-based WBC filters was studied. Filters were made of nonwoven fleece prepared from polyester, surface-modified polyester, or polypropylene fibers. Human platelet concentrates were filtered through experimental filters consisting of 8 to 54 layers of nonwoven fleece with mean pore sizes from 7.3 to 14.2 microns. Filters made of fleece of smaller pore size removed WBCs less effectively than filters with larger-pore fleece. Retention of lymphocytes and granulocytes gradually dropped to 0 percent as increasing loads were applied to the filters. The maximal retention capacity for these cell types (i.e., the number of cells retained when "saturating" numbers of WBCs were applied) was proportional to the number of layers of filter material used. Platelet retention did not correlate with WBC retention. Depth filtration, rather than mechanical sieving, seems to be the principal means of WBC removal by nonwoven fiber filters. A low initial number of WBCs in the component to be filtered is important for successful WBC filtration.     

IMPROVED TOLERABILITY OF FELODIPINE COMPARED WITH AMLODIPINE IN ELDERLY HYPERTENSIVES: A RANDOMISED,DOUBLE-BLIND STUDY IN 535 PATIENTS,FOCUSING ON VASODILATORY ADVERSE EVENTS

SUMMARY The primary aim of this double-blind, parallel group trial was to compare incidence of newly occurring vasodilatory adverse events in elderly patients treated with recommended once-daily doses of felodipine extended release (ER) or amlodipine. A total of 535 patients over 65 years old with a sitting diastolic blood pressure of 90-115 mmHg and/or systolic blood pressure 160-220 mmHg, were recruited at 46 centres worldwide. Patients were randomised to felodipine ER 2.5 mg or amlodipine 5 mg. If blood pressure was >160/90 mmHg after three or six weeks, felodipine ER was increased to 5 and 10 mg and amlodipine to 10 mg. After nine weeks, average doses of felodipine ER and amlodipine were 5.5 mg and 7.3 mg, respectively. Newly occurring vasodilatory adverse events were reported by 32% of felodipine ER patients and 43% of amlodipine patients (p=0.007). Both treatments effectively reduced blood pressure 24 hours post-dose. Using a low starting dose and individual titration, felodipine ER achieves good control of blood pressure with few vasodilatory side-effects.     

Inhibition of an anti-Pr1d cold agglutinin by citrate present in commercial red cell preservative solutions

A patient with known cold autoimmune hemolyticanemia was admitted for surgery. Routine cold agglutinin evaluations, using commercial red cells (RBCs) in modified Alsever's preservative solution, revealed a cold agglutinin titer of 4 to 16. However, using RBCs washed four times with saline, a high-titer (greater than 2000 at 4 degrees C) cold autoagglutinin was demonstrated. The cold agglutinin was shown to be an IgM kappa paraprotein with anti-Pr1d specificity. The addition of Alsever's solution to washed RBCs inhibited the cold agglutinin. Each major component of Alsever's solution (neomycin, chloramphenicol, inosine, dextrose, and citrate) was tested individually; only citrate inhibited the patient's cold agglutinin. Various compounds structurally related to citrate were tested and found to cause various degrees of inhibition. The strongest inhibition correlated with the presence of either three carboxyl groups on molecules devoid of double-bonded carbon atoms or two carboxyl groups in cis configuration. A panel of 54 cold agglutinins, including 7 with anti-Pr specificity, was analyzed. None was significantly inhibited by Alsever's solution, although one with anti-Pr2 specificity was weakly inhibited. In summary, these studies describe an anti-Pr1d cold autoagglutinin that was inhibited by citrate in RBC preservative solutions. The failure to detect such a cold agglutinin can result from not washing RBCs free of citrate before testing.     

A review of the Transitional Emergency Nurse Practitioner

Introduction

A retrospective exploratory study was conducted to (i) explore the practice patterns of a Transitional Emergency Nurse Practitioner (TENP) working across two urban Emergency Departments (ED); (ii) identify the demographic characteristics of the TENP patient cohort; and (iii) identify if TENP patients were appropriately and timely managed.

Method

The study was conducted across two hospital sites over two consecutive years for a 3-month period. Data collection occurred during the months of December through to February. TENP patients were identified by hospital electronic medical record and were then grouped into a model that included ‘Fast Track’ or ‘See and Treat’ cohort. The cohorts were then analysed for diagnostic groups, age, sex, length of stay, triage category, and re-presentations.

Results

The TENP worked a total of 600 h (Site 1 252 h; Site 2 348 h) across the study period. The TENP managed a total of 481 patients (262 Site 1; 220 Site 2) during the study period. The majority of patients (412; 84%) were managed in the ‘See and Treat’ cohort (Site 1 246, 94%; Site 2 166, 75%) and 70 patients (16%) were managed in the ‘Fast Track’ cohort (Site 1 16, 4%; Site 2 54, 25%). The median length of stay for TENP managed patients was 143 min, with 96% of patients leaving the ED in less than 8 h. There were no TENP unplanned re-presentations at either site. The TENP managed more male patients across both sites. The majority (75%) of patients the TENP managed had musculoskeletal and/or wound conditions or injuries.

Conclusion

TENP practice across the two Sydney metropolitan ED sites was similar. The model adapted for Tertiary Referral centres was appropriate for smaller urban EDs. The study supports existing evidence of timely and appropriate care being delivered by TENPs across Australian EDs. Given the work practice similarities, the study demonstrates that State and/or National standards and policies could be developed for emergency advanced practice roles.     

Uptake of Cationized Albumin Coupled Liposomes by Cultured Porcine Brain Microvessel Endothelial Cells and Intact Brain Capillaries

The suitability of protein-coupled liposomes as drug carriers for brain specific targeting was investigated using albumin (BSA) and cationized albumin (CBSA), respectively, as model proteins. Liposomes coated with polyethylene glycol (sterically stabilized, PEG-liposomes) were prepared from phosphatidylcholine, cholesterol, and a PEG-derivatized phospholipid and covalently coupled to thiolated BSA or CBSA. Liposomes were loaded with carboxy-fluorescein and rhodamine-labeled dipalmitoyl-phosphatidylethanolamine as hydrophilic and lipophilic marker compounds, respectively. The interaction of these constructs with monolayers of porcine brain capillary endothelial cells (BCEC) and freshly isolated porcine brain capillaries was studied by means of fluorescence assays and confocal laser scanning fluorescence microscopy (CLSFM). In contrast to BSA, CBSA was rapidly taken up by cultured BCECs. BSA-coupled liposomes did not interact with endothelial cells, whereas CBSA-coupled liposomes bound to cellular surfaces and exhibited time dependently a high intracellular accumulation. CBSA-conjugated liposomes were also taken up by intact brain capillaries. Cellular uptake could be inhibited by free cationized albumin, phenylarsineoxide, nocodazole, and filipin, but not by dansylcadaverine, suggesting a caveolae-mediated incorporation process. Immunostaining demonstrated a high expression of caveolin in the capillary endothelium. In conclusion, liposomes coupled to CBSA are taken up into brain endothelium via an endocytotic pathway and may therefore be a suitable carrier for drug delivery to the brain.     

Structural abnormalities of ventrolateral and orbitofrontal cortex in patients with familial bipolar disorder

Objectives: Abnormalities of ventral prefrontal function have been widely reported in bipolar disorder, but reports of structural abnormalities in the same region are less consistent. We examined the presence and location of ventral prefrontal abnormalities in a large sample of individuals with bipolar disorder and their relationship to gender, psychotic symptoms, and age. Methods: Structural magnetic resonance imaging brain scans were carried out on 66 individuals with bipolar disorder, type I, and 66 controls. Voxel‐based morphometry was used to examine differences in grey and white matter density between the groups and their relationship with a lifetime occurrence of psychotic symptoms and age. Results: Reductions in grey matter density were seen in the left and right lateral orbital gyri and the right inferior frontal gyrus, while white matter density reductions were seen in the corona radiata and the left temporal stem. In contrast, hallucinations and positive symptoms were associated with grey matter reduction in the left middle temporal gyrus. Age was more strongly associated with the right inferior frontal gyrus grey matter reductions in the bipolar group than in the controls, but not with any other finding. Conclusion: Abnormalities of the ventral prefrontal cortex are likely to be involved in the aetiopathology of bipolar disorder, while hallucinations appear to be more closely associated with temporal lobe abnormality, extending earlier work in schizophrenia. Further prospective studies are required to comprehensively address the trajectory of these findings.