Hemodynamic Parameters Influencing Clinical Performance of Novacor Left Ventricular Assist System

The interrelationships between hemodynamic variables including right ventricular (RV) performance with filling/ejection dynamics of the Novacor left ventricular assist system (LVAS) were determined in 10 of 11 patients who received LVAS as a bridge to heart transplant. Nine were successfully transplanted. Data were obtained intraoperatively, at periodic intervals up to 48 h postimplant and at explant. The hypotheses investigated included (a) RV performance influences LVAS filling characteristics and (b) LVAS pump output is influenced by systemic vascular resistance (SVR). During the period of LVAS support (2-126 days), pumping characteristics included a mean filling volume of 51 ml (range, 24-70), residual volume of 4.9 ml (range, 1-18), pump rate of 113/min (range, 63-175), and pump output of 5.81/min (range, 2.8-8.2). Multiple regression analysis identified pulmonary vascular resistance (PVR), RV stroke work index (RVSWI), and pulmonary capillary wedge pressure, but not RV ejection fraction, pulmonary artery pressure, or central venous pressure (CVP) as the most important correlates with LVAS filling volume (p less than 0.001, R2 = 0.6). In addition, LVAS pump output was influenced mainly by RVSWI, PVR, and SVR (p less than 0.001, R2 = 0.7). It was concluded that LVAS performance is highly dependent on RV function and systemic/pulmonary vascular resistances.     

Extracorporeal shock wave lithotripsy: impact on a large diagnostic radiology department.

Extracorporeal shock wave lithotripsy is a new therapeutic technology that has received instant and widespread acceptance. The history and technical aspects of the procedure are presented, but most importantly, the authors discuss radiology's role and note the importance of management's awareness of the potential impact on departmental fiscal, equipment and personnel resources.     

Sialyltransferase activity and hepatic tumor growth in a nude mouse model of colorectal cancer metastases.

Sialyltransferase activity (EC 2.4.99.6) was measured in the microsomal fraction of colorectal cancer cell lines using an assay based on the incorporation of [14C]CMP-sialic acid into asialofetuin. In the poorly differentiated lines MIP101 and Clone A, sialyltransferase activity had a Vmax of 0.36 and 0.31 nmol/mg protein/h, respectively, while the moderately differentiated to well-differentiated cell lines HT-29, CCL188, and CX-1 had Vmaxs of 2.46, 1.05, and 1.24 nmol/mg protein/h, respectively. All cell lines tested had a Km of 15.4 (+/- 0.7)(SD) mumol/liter. The better differentiated cells had higher levels of sialyltransferase activity, which correlated with their higher levels of sialic acid and their enhanced ability to form liver metastases in the nude mouse following intrasplenic injection compared to the poorly differentiated cell lines. Treatment of the cell lines with KI-8110, a CMP-sialic acid derivative which prevents incorporation of sialic acid into glycoconjugates, resulted in reduced formation of hepatic metastases by the colorectal carcinoma cell lines in the nude mouse model. It is suggested that reduced sialylation of adhesion molecules such as carcinoembryonic antigen may change the biology of the tumor cell, one consequence of which is the prevention of implantation of the cells into distant sites, resulting in a reduced incidence of metastases.     

Elbow ganglion arising from medial epicondyle pseudarthrosis.

We present a patient with an asymptomatic painless medial elbow swelling of one year's duration, which was diagnosed as a ganglion originating from a non-united avulsion fracture of the medial epicondyle with a pseudarthrosis. Medial elbow ganglia are unusual lesions typically arising from the medial aspect of the ulnohumeral joint capsule, often in combination with symptoms of cubital tunnel syndrome. To our knowledge, a ganglion arising from a pseudarthrosis has not been reported in the literature, and should be considered in the differential diagnoses of lesions encountered over the site of fracture non-union in proximity to a joint.     

A comparison of dummy variable versus traditional multiple discriminant function analysis.

The authors compare the use of dummy variable and traditional multiple discriminant function analysis when dealing with research questions where ratio or nominal scale independent variables can be used. A healthcare-related example of using dv MDF is given and the authors conclude that it is superior to traditional MDF for determining variable importance and developing market segment profiles.     

Biological characteristics of newly diagnosed poor prognosis acute myelogenous leukemia

A pilot study was conducted of the biological characteristics of the leukemia cells of newly diagnosed patients with poor prognosis acute myelogenous leukemia (AML). This study included measurements of the pretherapy proliferative rate of the leukemia cells in vivo, assessment of differentiation in vivo during remission induction therapy, and the level of expression of the fms, myc, and IL1β genes in pretherapy leukemia cells. Short cell cycle times were characteristic of the best prognostic category and were associated with a rapid reduction in marrow leukemia cells in cytosine arabinoside (araC)-sensitive patients. Expression of c-fms was associated with rapid reduction in marrow leukemia cells during araC therapy and with a successful treatment outcome. Expression of the IL1β gene was associated with short remissions. These studies suggest that when compared to newly diagnosed standard prognosis AML, the leukemia of poor prognosis patients is more likely to exhibit long cell cycle times, low levels of fms expression, and is less likely to be associated with myeloid differentiation during remission induction therapy. © 1993 Wiley-Liss, Inc.     

The use of a low phenylalanine diet in response to the challenging behaviour of a man with untreated phenylketonuria and profound learning disabilities

If phenylketonuria (PKU) is not treated from an early age with a reduced phenylalanine diet, irreversible brain damage may occur. Although dietary intervention can do nothing to alter this impairment once it occurs, there is some evidence to suggest that a low phenylalanine diet may help to reduce the level of behavioural disturbances frequently experienced by people with untreated PKU. Using this evidence, dietary intervention was used in response to the challenging behaviour of a 30-year-old man with profound learning disabilities. Initial improvements were observed, but overall the results were inconclusive. Possible confounding factors are discussed. An unusual reaction to neuroleptic medication whilst on the diet is also documented.     

Signal transduction pathways involved in the acute potentiation of NMDA responses by 1S,3R-ACPD in rat hippocampal slices.

1. A grease-gap recording technique has been used to investigate the mechanisms underlying the acute potentiation of N-methyl-D-aspartate (NMDA) responses by aminocyclopentane-1S,3R-dicarboxylic acid (1S,3R-ACPD) in area CA1 of rat hippocampal slices. 2. 1S,3R-ACPD (10 microM), but not 1R,3S- ACPD (10 microM), potentiated submaximal responses to NMDA (dose-ratio of 0.81 +/- 0.02 (mean +/- s.e.mean); n = 55), but not to alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), in a readily reversible manner. Potentiation also occurred in slices treated with 0.2 microM tetrodotoxin, and in slices perfused with Mg(2+)-free medium. 3. 1S,3R-ACPD-induced potentiation was unaffected by the protein kinase inhibitors K-252b (0.1 microM) and staurosporine (1 microM) and the intracellular Ca2+ store depletor, thapsigargin (10 microM). Coapplication of staurosporine and thapsigargin was also without effect. 4. 1S,3R-ACPD-induced potentiation was unaffected by inhibitors of arachidonic acid formation, bromophenacyl bromide (50 microM) and RG80267 (100 microM). Arachidonic acid (10-50 microM) depressed reversibly NMDA-induced responses. The potentiation was unaffected by 8-bromo cyclic AMP (500 microM) or the PKA inhibitor Rp-adenosine 3,5-cyclic monophosphothioate triethylamine (Rp-cAMPS; 50 microM). 5. 1S,3R-ACPD-induced potentiation was abolished in slices perfused with Ca(2+)-free medium. The potentiation was also blocked by phorbol-12,13-diacetate (1 microM), in a staurosporine-sensitive manner. 6. It is concluded that the potentiation of NMDA responses by 1S,3R-ACPD is not mediated by protein kinase A or C, by release of Ca2+ from intracellular stores or by arachidonic acid.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tumor vascular signals in renal masses: detection with Doppler US

The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses.     

Changing antibiotic prescribing by educational marketing

A controlled cross-over study in 12 Victorian public hospitals was performed to examine the power of marketing techniques in influencing prescribing. The targeted prescribing behaviour was the use of antibiotic prophylaxis in surgery, and the criteria for judging the appropriateness of therapy were its duration and timing, as are detailed in the fourth edition of the booklet Antibiotic guidelines. The first intervention was mounted in 1985 in six hospitals (two metropolitan teaching hospitals, one suburban general hospital and three rural hospitals), and six matched hospitals acted as control hospitals. One year later, the intervention was mounted in the six hospitals that previously had been the control hospitals. The interventional campaign consisted of material that was similar to that which is used by the pharmaceutical industry, including an "academic" representative. Its effect was assessed by audits that were performed before and after the first interventional campaign and again, one year later, after the second interventional campaign. The proportion of antibiotic courses that were assessed as satisfactory in terms of duration increased significantly after the first campaign in the hospitals where the intervention was mounted. No significant changes in prescribing occurred in the control hospitals. In the hospitals which were control hospitals in 1985, and in which the intervention occurred in 1986, the proportion of antibiotic courses that were assessed as satisfactory also increased significantly after the interventional campaign. A fall-off in performance occurred during the 12 months after the campaign in the 1985-interventional hospitals. Calculated cost savings more than outweighed the costs of the campaign. We conclude that inappropriate prescribing behaviour in hospitals can be modified successfully by educational marketing techniques.