Autosomal dominant thrombocytopenia with microthrombocytes: a family study.

A family demonstrating autosomal dominant thrombocytopenia is described. A 28-year-old Malay housewife was found to have a platelet count of 40 x 10(9)/l with a low mean platelet volume (6.8 fl) while being investigated prior to ovarian cystectomy.

High-luminosity blue and blue-green gallium nitride light-emitting diodes.

Compact and efficient sources of blue light for full color display applications and lighting eluded and tantalized researchers for many years. Semiconductor light sources are attractive owing to their reliability and amenability to mass manufacture. However, large band gaps are required to achieve blue color.

Markers of thromboembolization in a bovine ex vivo left ventricular assist device model.

The production of blood microemboli (BME) was studied using an ex vivo exteriorized left ventricular assist device (LVAD) model in calves. Each of eight calves received a series of three LVADs, each operating for 24 hr. Blood microemboli were measured directly by a laser (624 nm and 828 nm) light scattering microemboli detection (LSMD) system through the LVAD outflow cannula and by constant pressure filtration (CPF) of blood samples from the LVAD outflow cannula.

Oxygen metabolism in animals with total artificial hearts.

The relationship between indices of oxygen metabolism has been widely used in clinical practice to evaluate the adequacy of tissue perfusion, to predict the outcome of the critically ill patient, and to evaluate the effectiveness of therapies. This study quantitated and correlated the relationship between oxygen delivery (DO2), oxygen consumption (VO2), and oxygen extraction rate (EO2) in 14 animals with total artificial hearts (TAH) to investigate the oxygen metabolism in animals with TAH during different physiologic and pathologic conditions. These 14 animals were subdivided into healthy, critical, and exercise groups.

Magnetic field enhancement of antibiotic activity in biofilm forming Pseudomonas aeruginosa.

Device related infection initiated by biofilm bacteria are often difficult to resolve with antimicrobial therapy. Study results indicate that application of static magnetic fields may enhance the activity of gentamicin against biofilm forming Pseudomonas aeruginosa adherent to a polymer substrate. Results indicate a maximal reduction of 86.

Anaerobic threshold in total artificial heart animals.

The anaerobic threshold represents an objective measure of functional capacity and is useful in assessment of pulmonary and cardiovascular dysfunction. This study determined the anaerobic threshold in total artificial heart animals and evaluated the performance of the total artificial heart system. Five animals with total artificial hearts were put under incremental exercise testing after exercise training.

Acute phase vascular endothelial injury: a comparison of temporary arterial occlusion using an endovascular occlusive balloon catheter versus a temporary aneurysm clip in a pig model.

We compared the degree of acute endothelial injury after temporary vessel occlusion using two different occlusion modalities--external clipping and endovascular balloon occlusion. The common carotid and subclavian arteries in eight weanling pigs were temporarily occluded with either a 5 Fr occlusion balloon catheter or a temporary microvascular clip for 0 (control), 5, 10, and 30 minutes. Two animals (eight vessels; four clip and four balloon occluded) were used at each time interval.

Aortic valve replacement with pulmonary homografts. Early experience.

The increasing use of the aortic homograft as aortic valve substitute and the limited availability of donor valves prompted us to consider the pulmonary homograft as an alternative substitute for aortic valve replacement. The aim of our study is to compare the ultrastructural and biomechanical properties of pulmonary homograft leaflets with those of their aortic counterpart and to present the early results of using the pulmonary homograft for aortic valve replacement. Light and transmission electron microscopy have shown that pulmonary homograft leaflets are thinner than the aortic with a lesser content of elastic tissue in the ventricularis layer.

Alprostadil: an effective antiplatelet agent for calves.

Aspirin and other nonsteroidal, antiinflammatory drugs inhibit human platelets, but their effect as an antiplatelet agent on bovine platelets is not certain. Since calves are used for cardiovascular implant research, need exists for an effective antiplatelet agent for this animal model. After screening a number of potential antiplatelet drugs for calves, Alprostadil (prostaglandin E1) appeared to be the most promising.

In vitro investigation of thrombogenesis in rotary blood pumps.

Thrombus formation at sealing and stagnation areas remains a major problem in the development of rotary blood pumps. Until now, the complex phenomena could only be studied in vivo. In this study, an in vitro mock circulation previously used for hemolysis studies was adapted for thrombosis evaluation.

Adaptive responses of total artificial heart animals to treadmill exercise.

The hemodynamic and metabolic adaptations to exercise in five calves implanted with the Utah-100 total artificial heart (TAH) were investigated. The outputs of the left and right ventricles (LCO, RCO) were measured with a cardiac output monitoring and diagnostic unit (COMDU). Arterial and venous oxygen content (CaO2, CvO2) and blood lactate levels (Lac) were measured by blood gas analysis and enzymatic methods.

Psychiatric morbidity: prevalence, associated factors and significance.

A cross-sectional observational systematic study was carried out on ambulatory patients at a tertiary care hospital to determine the probable prevalence, associated factors and significance of psychiatric morbidity by using an Urdu translation of the hospital anxiety and depression (HAD) scale over a period of 6 days in a week. Results showed a prevalence of 38.4% which is slightly higher than what has been generally reported (30%).

Interaction of heparin with polyallylamine-immobilized surfaces.

A new method to bind ionically and remove heparin from solution and dilute serum is described. Utilizing cellulose diacetate (CA) as the polymer substrate, a cationic polymer chain--poly(allylamine)-PALA--was immobilized directly onto the CA surface and onto the surface using poly(ethylene glycol) (PEG) spacer groups. The ionic interaction between the anionic heparin molecule and the cationic PALA polymer is specific and effective to remove heparin from the bulk solution.

111Indium labeling of microorganisms to facilitate the investigation of bacterial adhesion.

The ability of bacteria to adhere to polymeric interfaces has attracted considerable attention in recent years. Metabolic labeling of microorganisms with 35S-methionine or other beta-emitters is commonly utilized for quantification of bacterial adhesion to biopolymers. Since the use of these isotopes is cumbersome, the possibility of labeling the microorganisms with 111Indium, a strong gamma-emitter, was explored.

Heparin removal from blood using poly(L-lysine) immobilized hollow fiber.

Based on the negative charge density characteristics of heparin, an affinity adsorption technique has been developed for the removal of heparin from blood. Poly(L-lysine) . HBr (PLL .

Animal implantation results with the Utah-100 total artificial heart.

The Utah-100 total artificial heart was designed to have increased reliability over the Jarvik-7 total artificial heart, achieve better fit, and minimize device associated thrombus formation, without decreasing the function. The Utah-100 heart was tested in 28 calves and 3 sheep. The smallest animal at the time of implantation weighted 54 kg.

The influence of harvesting technique on endothelial preservation in saphenous veins.

To study optimal conditions of preparation of saphenous veins as coronary artery bypass grafts, segments of saphenous veins were obtained from 29 consecutive patients undergoing coronary artery bypass grafting. The saphenous vein segments were divided into three groups. In Group I, 10 saphenous vein segments were harvested using a "no-touch" technique without any other preparation aids.

Microbially infected thrombus in animals with total artificial hearts.

In a retrospective study of 330 animals with total artificial hearts (TAH), 103 (31%) had microbially infected thrombi (MIT). The incidence of MIT approximated 75% in the animals surviving more than 100 days. The most common pathogen isolated from animals with MIT was Pseudomonas.

SPUU-PEO-heparin graft copolymer surfaces. Patency and platelet deposition in canine small diameter arterial grafts.

The influence of an SPUU-PEO-Heparin (B-PEO-HEP) copolymer coated blood contacting surface on patency and platelet deposition in small diameter (4 mm i.d.) Biomer grafts was investigated using a canine model.

The role of plasma proteins in formation of obstructive protamine complexes.

Formation of complexes between heparin and protamine (in saline), or heparin, plasma proteins, and protamine (in plasma) was assessed by measurements of light transmission through different test solutions. To examine the formation of these complexes, 125I-labeled protamine was used. Addition of 125I-protamine to plasma or blood resulted in the sedimentation of 125I-protamine in the form of insoluble complexes.

Detection of microemboli by constant-pressure filtration during in vitro circulation of bovine and human blood.

The constant-pressure filtration (CPF) method has been developed to assess blood microemboli (BME) in terms of their ability to occlude microvascular flow. Previous reports suggest that the method is sensitive to the effects of platelet stimulation and to blood-pumping conditions. BME production and heparin activity were studied in bovine and human blood pumped by a Pellethane ventricle with Pellethane molded valves connected via smooth quick-connects to a Pellethane horseshoe-shaped reservoir.

Quantification of perivalvular thrombus formation in blood pumps by polar coordinate mapping.

A polar coordinate mapping technique (PCMT) to quantitatively describe perivalvular thrombus formation was applied in the examination of prosthetic valves from paracorporeal assist devices. The method begins by photographing the upstream and downstream views of the freshly retrieved valves using transparency film. The valve images are then projected onto 10 x planforms of the valves, and the boundaries of the observable thrombi are traced.