bluuebunny/crossref_metadata_2025_split huggingface dataset:
Are the Jarvik Artificial Ventricles Limited By Inflow Resistance?
Authors: Lioi Anthony P. , Nielsen Steven D. , Olsen Don B. 
Published: November 2008

ABSTRACTThe pneumatic total artificial heart has been assumed to be inflow limited. Mock circulation studies on the Jarvik‐5 and Jarvik‐7 artificial ventricles seemed to support this assumption because a Starling's response comparable to the natural heart was not achieved. Unfortunately, mock circulation studies do not separate the effects of valvular regurgitation from inflow resistance. By using a simple filling tank, filling times were determined for the Jarvik ventricles that were a function of inflow resistance alone. Theoretical maximum cardiac outputs based on these inflow resistance‐dependent filling times were then calculated. For filling pressures around 5 mmHg and under modest diastolic vacuum of 5 cm H2O, the Jarvik ventricles yield a theoretical cardiac output as good as the natural heart's. Thus, inflow resistance is not a limiting factor and valvular regurgitation is left as the most likely cause of a less than optimal Starling's response on mock circulation and in vivo.
Numerical Simulation of Blood and Plasma Flow through the Petschek Flow Chambers
Authors: Johnson Webster R. , Madras Peter N. 
Published: November 2008

ABSTRACTThe Stagnation Point Flow Experiment is a popular means for studying blood‐surface interactions in a surface strain rate gradient. The strain rate distribution on the test surface of the flow chamber used in this experiment was originally assumed to be simply proportional to the radial distance from the stagnation point. A numerical simulation of the flows through the five most frequently used chambers shows that this is true only for one of the chambers, approximately so for another, and not true for the other three. An additional numerical simulation indicates the blood should purge the saline priming liquid within a few seconds at the beginning of the experiment.
Performance of a New Type of Blood Oxygenator
Authors: Merchuk Jose C. , Dana Rene D. , de Lew Maria M. , Dvilansky Alexander , Meyerstein Naomi , Tamir Abraham 
Published: November 2008

ABSTRACTA new type of direct‐contact oxygenator has been tested satisfactorily on dogs in nine experiments. It is based on the principle of the “packed column“ and has the advantage of a small hold‐up (meaning a small priming volume), no formation of foam, and gentle flowing of the blood. The apparatus is simple enough to be commercially available at a low price and discarded after use. Both PO2 increase and PCO2 decrease were satisfactory and plasma hemoglobin values remained low after 75 minutes of perfusion. Preliminary in vitro experiments on ox and human blood showed a low degree of blood damage.
Acid Citrate Dextrose Reduces Platelet Retention During In Vitro and In Vivo Dog Hemoperfusion: A Comparative Study of Different Charcoal Adsorbers
Authors: Tangerman Albert , Snel Pleun , van Schaik Annie , van Tongeren Jan H.M. 
Published: November 2008

ABSTRACTHemoperfusion through charcoal adsorbers has often been proposed for use in exogenous and endogenous intoxication. A serious drawback of this technique is the often encountered loss of platelets and leucocytes. In vitro hemoperfusion studies with heparinized human blood and in vivo hemoperfusion of heparinized Labrador dogs through different types of charcoal adsorbers (Becton‐Dickinson [B‐D], Gambro, Haemocol) clearly demonstrated that addition of the anticoagulant acid citrate dextrose (ACD) might reduce the loss of platelets. ACD seemed to have no distinct influence on leucocyte retention.
The Effect of Hemofiltration on Fiber Platelet Concentration
Authors: Drake Kenneth L. , Eckstein Eugene C. 
Published: November 2008

ABSTRACTExperimental methods and apparatus were developed to measure platelet concentration in an ultrafiltering hollow fiber with blood and ultrafiltrative flow rates that are characteristic of current hemofiltration practice. Values are presented for the adjusted local platelet concentration, which allows for the expected increase due to loss of ultrafiltrate volume. Platelet concentrations in fiber samples are of interest since ultrafiltration can create platelet polarization in a fashion similar to the concentration polarization that occurs for proteins. For many combinations of inlet flow rate, ultrafiltrative flow rate, and fiber dimension, there are significant elevations in adjusted fiber platelet concentration. The adjusted platelet concentrations of the outflow samples are nominally equal to those of the feed (reservoir) samples; thus, reaction and adhesion of platelets is not a significant source of fiber concentration. Experiments with fibers of different diameters indicate that, as expected in concentration polarization, the excess platelets are located near the wall. Data for the fiber platelet concentration depend in a complex fashion upon the inlet wall shear rate and ultrafiltrative velocity. For certain fixed ultrafiltrative velocities, a maximum fiber platelet concentration occurs at an intermediate inlet wall shear rate. The data are qualitatively explained by an extension of a published model involving diffusive, ultrafiltrative, and wall‐induced fluxes of red cells and platelets.
Development of Means to Augment Peritoneal Urea Clearances: The Synergistic Effects of Combining High Dialysate Temperature and High Dialysate Flow Rates with Dextrose and Nitroprusside
Authors: De Santo Natale G. , Capodicasa Giuseppe , Capasso Giovambat‐tista , Giordano Carmelo 
Published: November 2008

ABSTRACTBy combining: a) nitroprusside (4.5 mg/L); b) dextrose concentration of 42.5 gm/L; c) dialysate temperature of 42°C and d) dialysate flow rates of 3.5 L/hour in seven uremic subjects on C APD, it was possible to increase peritoneal urea clearance up to 35.6 ± 3.8 ml/min/1.73 m2 (range 30.3 to 42.2). This effect in six out of seven cases was associated with a fall in blood pressure and an increase in heart rate. This study is the first which deals with a combination of these factors and demonstrates that this approach is easy to handle, does not require the use of mechanical devices, and is available at any bedside.
Maintenance Hemodialysis in End‐Stage Renal Disease Associated with Spinal Cord Injury
Authors: Vaziri N. D. , Bruno A. , Byrne C. , Mirahmadi M. K. , Nikakhtar B. , Gordon S. , Zeien L. 
Published: November 2008

ABSTRACTData on maintenance hemodialysis in end‐stage renal disease (ESRD) associated with spinal cord injury (SCI) are lacking. Forty‐three SCI‐ESRD patients treated with hemodialysis in our unit were retrospectively studied. A control group of ESRD patients without SCI were included for comparison. Predialysis concentrations of Na, K, bicarbonate, creatinine, albumin, calcium, and phosphorus and anion gap were significantly lower in the SCI group than in the control group. In contrast, chloride concentration was significantly higher in the SCI patients. Hemodialysis was equally effective in providing azotemia control and acid‐base, electrolyte, and fluid balance in both groups. Interdialytic weight gain in the SCI group was significantly less than that of the control group. Hypotensive episodes during dialysis were quite common in the SCI patients. Interestingly, hypertensive episodes during or shortly after dialysis were also noted with considerable frequency. The hypotensive episodes usually responded to blood flow reduction and/or fluid administration. Hypertensive episodes were usually mild to moderate and reversed with continued dialysis without requiring vigorous intervention. The leg cramps often seen in ambulatory patients due to rapid ultrafiltration and fluid shifts were uncommon among the SCI patients. However, diffuse painful muscle spasms caused by uninhibited spinal reflexes were observed with considerable frequency and presented a difficult therapeutic problem. Due to prolonged immobilization and other factors, SCI‐ESRD patients appear to be at high risk of thromboembolic disorders. SCI‐ESRD patients thus appear to differ from the ambulatory ESRD patients from both clinical and biochemical viewpoints. These specific feaures can be of significant value with respect to the dietary and therapeutic considerations.
How to Comply with the Food and Drug Administration's “Investigational Device Exemption (IDE)“ Regulations Including an Application Form (Revised January 1982) Prepared by the ASAIO Standards Committee,
Authors: Morton William A. , Dobelle William H. , Lysaght Michael J. , Serkes Kenneth , Siemsen Arnold , Villarroel Fernando 
Published: November 2008

ABSTRACTThis is a revision of the IDE Application Form, “How to Comply with the Food and Drug Administration's New ‘Investigational Device Exemption (IDE)’ Regulations, Including an Application Form“ originally published in Artificial Organs, Volume 4, Number 4, November 1980.This publication updates the IDE application form to facilitate compliance with the amended investigational device exemption regulations now in effect.
Intermittent Vascular Access for Extracorporeal Circulation in Conscious Rats: A New Technique
Authors: Tabata Yoichiro , Chang Thomas Ming Swi 
Published: November 2008

ABSTRACTA new technique is described for repeated intermittent access to the systemic circulation in fully conscious rats for infusion or extracorporeal circulation. The femoral artery and vein of each rat were cannulated. The cannulas were then passed subcutaneously and exteriorized through the skin of the tail 2 cm from its base. The exposed cannulas were protected by a special plastic device. This new approach did not immobilize the rat except during access to the circulation; even then, only the distal portion of the tail was immobilized, thus allowing the animal to move freely. This way repeated access to the systemic circulation was easily achieved in the fully conscious rat.
Furosemide‐Induced Increase in Urinary and Peritoneal Excretion of Uric Acid During Peritoneal Dialysis in Patients with Chronic Uremia
Authors: Grzegorzewska Alicja , Baczyk Kazimierz 
Published: November 2008

ABSTRACTIntermittent peritoneal dialysis was performed in 17 patients with chronic uremia in order to observe the effect of furo‐semide added to the dialysate on urinary and peritoneal elimination of uric acid. Two kinds of dialysate were used: moderately hypertonic (osmolality, 431.2 mOsm/kg of water) and slightly hypertonic (osmolality, 368.9 Osm/kg of water). Significant increases in urine volume, urinary and peritoneal excretion of uric acid, and renal and peritoneal clearances were found. The increase in urinary excretion of uric acid exceeded that of urine volume. These findings were interpreted to be the result of furosemide action on renal function after being transferred through the peritoneum into the blood stream with the concomitant increase in the uric acid shift from the circulation into the peritoneal cavity. We concluded that the addition of furosemide is useful in increasing uric acid elimination in patients with chronic uremia.
Electrical Energy Converters for Practical Human Total Artificial Hearts‐An Opinion in Support of Electropneumatic Systems
Authors: Jarvik Robert K. 
Published: November 2008

Summary: Until recently, most artificial hearts have served as research tools to acquire further knowledge necessary ultimately to design practical systems for human use. Transcutaneous systems or percutaneous systems utilizing permanently implanted energy converters, batteries, and electronics packages have a number of substantial problems that would not exist if most system elements were kept outside the body. These problems include physiologic control, fit and fixation, foreign body infection, hermetic sealing, cable insulation and fatigue, inherent system complexity, stringent requirements for maintenance‐free operation with long‐term high reliability, and high cost. Percutaneous systems, particularly those in which only the blood pump is implanted, are an attractive choice for practical systems in the near future. A wearable, battery‐powered electropneumatic total heart system should be developed.A practical artificial heart is one that patients can live with. Tether‐free, electrically powered devices certainly have the potential to provide an acceptable quality of life. Energy converter design must be part of an integrated systems approach that someday makes the crucial decision to utilize either the transcutaneous or percutaneous approach. There are many difficult technical problems with transcutaneous systems that can be avoided with percutaneous leads. Furthermore, the percutaneous approach leaves external components accessible for maintenance and replacement without surgery. In my opinion, percutaneous portable electropneumatic systems have the best potential for practical application to large numbers of human patients within the foreseeable future. They are particularly suited to orthotopic total artificial hearts using free diaphragm or tethered‐sac designs. Their development should be emphasized at this time.
Study on Sodium and Potassium Balance During Hemodialysis
Authors: Kotyk P. , Lopot F. , Czech J. Bláha 
Published: November 2008

It is the goal of this section to publish material that provides information regarding specific issues, aspects of artificial organ application, approach, philosophy, suggestions, and/or thoughts for the future.Abstract: To acquire data for adequate ultrafiltration (UF) control, sodium and potassium balance was investigated during hemodialysis (HD) in 16 hemodialyzed patients. Overall balances were evaluated from concentration measurements of the in‐ and outflowing dialysate and pre‐ and postdialysis plasma. The diffusive and convective part of the electrolyte removal and its intra‐ and extracellular space (ICS, ECS) component were calculated. During a 5‐h HD, 40–110 mmol of potassium is removed, predominantly by diffusion (72–88%). Calculation shows that 40–70% of the removed amount is taken from the ICS. Sodium's overall HD showed much higher scatter, ranging from positive values to 500 mmol removal. The diffusive component was positive in most cases. By ultrafiltration sodium is removed in all cases. Calculations also showed in all cases that sodium was delivered to the ICS. This is in contradiction with the general belief that exchangeable sodium is distributed solely in ECS (1,2,6,7). This may be a sign of the effort to keep changes of ICS osmotic load at a minimum. Based on the finding of the exchange of sodium for potassium in the cellular wall, a method has been devised to calculate the UF fraction removed from EC (UFEC) expressed as a coefficient KEC=UFEC/UFToT, with UFToT being the total fluid volume removed during the HD session.
Comparative Hemolysis Study of Clinically Available Centrifugal Pumps
Authors: Naito Kozo , Suenaga Etsuro , Cao Zhi‐Li , Suda Hisao , Ueno Tetsuya , Natsuaki Masafumi , Itoh Tsuyoshi 
Published: November 2008

AbstractCentrifugal pumps have become important devices for cardiopulmonary bypass and circulatory assistance. Five types of centrifugal pumps are clinically available in Japan. To evaluate the blood trauma caused by centrifugal pumps, a comparative hemolysis study was performed under identical conditions. In vitro hemolysis test circuits were constructed to operate the BioMedicus BP‐80 (Medtronic, BioMedicus), Sams Delphin (Sarns/3M Healthcare), Isoflow (St. Jude Medical [SJM]), HPM‐15 (Nikkiso), and Capiox CX‐SP45 (Terumo). The hemolysis test loop consisted of two 1.5 m lengths of polyvinyl chloride tubing with a 3/8 ‐inch internal diameter, a reservoir with a sampling port, and a pump head. All pumps were set to flow at 6 L/min against the total pressure head of 120 mm Hg. Experiments were conducted simultaneously for 6 h at room temperature (21oC) with fresh bovine blood. Blood samples for plasma‐free hemoglobin testing were taken, and the change in temperature at the pump outlet port was measured during the experiment. The mean pump rotational speeds were 1,570, 1,374, 1,438, 1,944, and 1,296 rpm, and the normalized indexes of hemolysis were 0.00070, 0.00745, 0.00096, 0.00066, 0.00090 g/100 L for the BP‐80, Sarns, SJM, Nikkiso, and Terumo pumps, respectively. The change in temperature at the pump outlet port was the least for the Nikkiso pump (1.8oC) and the most with the SJM pump (3.8oC). This study showed that there is no relationship between the pump rotational speed (rpm) and the normalized index of hemolysis in 5 types of centrifugal pumps. The pump design and number of impellers could be more notable factors in blood damage.
Flight and oviposition behaviour of the African stem borer, Busseola fusca, on various host plant species
Authors: Calatayud Paul‐André , Guénégo Hervé , Ahuya Peter , Wanjoya Antony , Le Rü Bruno , Silvain Jean‐François , Frérot Brigitte 
Published: November 2008

AbstractThe African stem borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae), is an important pest of maize and sorghum in sub‐Saharan Africa. As in many other lepidopteran insects, the ability of B. fusca to recognize and colonize a variety of plants is based on the interaction between its sensory systems and the physical and chemical characteristics of its immediate environment. In this study, we tried to identify the behavioural steps of B. fusca leading to host selection and oviposition. Three Poaceae species commonly cultivated in Kenya for human consumption and animal forage were used in this study: the two most preferred hosts, maize (Zea mays L.) and sorghum [Sorghum bicolor (L.) Moench], and one non‐preferred host, Napier grass (Pennisetum purpureum Schumach). Wind tunnel observations revealed that volatiles produced by the different plant species did not appear to strongly influence the general orientation of B. fusca towards the plant, as similar behavioural steps were exhibited by the female moth regardless of the plant species involved. This indicated that the females were not able to recognize their preferred hosts from a distance. After landing, the female typically swept her ovipositor on the plant surface, simultaneously touching it with the tips of her antennae, and then oviposited. This behaviour was more frequently observed on maize and sorghum than on Napier grass, and indicated that both antennal and ovipositor receptors are used by the female moths to evaluate the plant surface before deciding to oviposit. As a result, the females laid more eggs on the two crops than on Napier grass. We conclude therefore that females recognized their preferred hosts only after landing. Tactile and contact‐chemoreception stimuli from the plants seemed to play a major role in oviposition decisions of B. fusca.
Gene‐drive in age‐structured insect populations
Authors: Huang Yunxin , Lloyd Alun L. , Legros Mathieu , Gould Fred 
Published: November 2008

AbstractTo date, models of gene‐drive mechanisms proposed for replacing wild‐type mosquitoes with transgenic strains that cannot transmit diseases have assumed no age or mating structure. We developed a more detailed model to analyze the effects of age and mating‐related factors on the number of engineered insects that must be introduced into a wild population to achieve successful gene‐drive based on the Medea and engineered underdominance mechanisms. We found that models without age‐structure and mating details can substantially overestimate or underestimate the numbers of engineered insects that must be introduced. In general, introduction thresholds are lowest when young adults are introduced. When both males and females are introduced, assortative mating by age has little impact on the introduction threshold unless the introduced females have diminished reproductive ability because of their age. However, when only males are introduced, assortative mating by age is generally predicted to increase introduction thresholds. In most cases, introduction thresholds are much higher for male‐only introductions than for both‐sex introductions, but when mating is nearly random and the introduced insects are adults with Medea constructs, male‐only introductions can have somewhat lower thresholds than both‐sex introductions. Results from this model suggest specific parameters that should be measured in field experiments.
Elevated choroidal blood flow velocity during systemic corticosteroid therapy in Vogt–Koyanagi–Harada disease
Authors: Hirose Shigeki , Saito Wataru , Yoshida Kazuhiko , Saito Michiyuki , Dong Zhenyu , Namba Kenichi , Satoh Hisao , Ohno Shigeaki 
Published: November 2008

Abstract.Purpose:  Laser speckle flowgraphy (LSFG) can be used to non‐invasively visualize the haemodynamics of choroidal circulation and the vascular pattern. The purpose of this study was to examine the ability of LSFG to quantitatively evaluate blood flow velocity at the macula in patients with Vogt–Koyanagi–Harada (VKH) disease before and after systemic corticosteroid therapy.Methods:  Prednisolone (200 mg/day) was systemically administered in 10 VKH disease patients with serous retinal detachment at the macular area. The drug was gradually tapered to zero over a 6‐month period. Laser speckle flowgraphy measurements were taken in the 20 eyes of these patients at their initial visit and at 1, 4 and 12 weeks after the onset of therapy. Square blur rate (SBR), a quantitative index of relative blood flow velocity, was calculated using LSFG.Results:  Serous retinal detachment resolved within 4 weeks after treatment and visual acuities improved to > 1.0 in almost all cases. There were significant increases in average SBR at the macula at 4 weeks after treatment compared with at 1 week after treatment, and also at 12 weeks after treatment compared with at 4 weeks after treatment.Conclusions:  These results suggest that systemic corticosteroid therapy improves inflammation‐related impairment in choroidal blood flow velocity at the macula. Laser speckle flowgraphy can evaluate the effect of systemic corticosteroid therapy by enabling comparisons between measurements of blood flow velocity, which is considered to reflect inflammation activity in the choroid.
The crystal chemistry of the gedrite-group amphiboles. I. Crystal structure and site populations
Authors: Schindler M. , Sokolova E. , Abdu Y. , Hawthorne F. C. , Evans B. W. , Ishida K. 
Published: November 2008

AbstractThe crystal structures of twenty-five orthorhombic Fe-Mg-Mn amphiboles, a = 18.525 – 18.620, b = 17.806-18.034, c = 5.264-5.303 Å, V = 1737.6-1776.7, space group = Pnma, Z = 4, have been refined to R indices in the range 2.1–7.8% using 790–1804 unique observed reflections measured with Mo-Kα X-radiation on a Bruker P4 automated four-circle diffractometer equipped with a 1K CCD detector. The quality of the refinements is strongly a function of the [4]Al content of the crystals because of unmixing in the central part of the series due to the presence of a low-temperature solvus. The amphibole crystals were analysed by electron microprobe subsequent to collection of the X-ray intensity data and span the anthophyllite-gedrite series from 0.17–1.82 [4]Al a.p.f.u. Mössbauer spectroscopy shows that the amphiboles of this series commonly contain small but significant amounts of Fe3+ . The amount of [4]Al is linearly related to the grand <T-O> distance by the equation <T-O> = 1.6214 + 0.171 [4]Al, R = 0.980; the slope of this relation is not significantly different from that characteristic of a hard-sphere model. The <T-O> distances indicate the following site preference for [4]Al: T1B > T2B > T1A » T2A. The <M2-O> distances are compatible with all [6]Al and Fe3+ ordered at the M2 site. The grand <M1,2,3 '3 –O> distance is related to the mean radius of the constituent cations, <rM1,2,3>, by the equation ≪M1,2,3-O≫ = 1.4684 + 0.8553(7) <rM1,2,3>.