bluuebunny/crossref_metadata_2025 huggingface dataset:
Background and perioperative risk factors for prolonged hospital stay after resection of colorectal cancer
Authors: Rickard Matthew J. F. X. , Dent Owen F. , Sinclair Gael , Chapuis Pierre H. , Bokey E. Leslie
Published: December 2004

Background:  The aim of this study was to identify independent background and perioperative risk factors for prolonged postoperative hospital stay among patients having a resection for colorectal cancer.

Methods:  Data from 1095 consecutive resections performed by specialist colorectal surgeons between 1995 and 2001 were examined by multiple least squares regression. Each putative risk factor was coded 0 if absent and 1 if present and postoperative stay was measured in days, so that the unstandardized partial regression coefficients (B) represent days of additional stay if the factor was present. Confidence intervals are at the 95% level.

Results:  Of 35 factors examined, the following 11 had a significant independent association with postoperative stay: urgent operation (B = 4.2, CI 2.2−6.2); preoperative stay>5 days (B = 4.2, CI 2.7−5.7); perioperative transfusion (B = 3.1, CI 2.2−4.2); adjacent organ or structure involved (B = 3.0, CI 1.2−4.9); stoma constructed (B = 2.6, CI 1.8−3.5); peripheral vascular disease (B = 2.3, CI 0.4−4.1); age ≥75 years (B = 2.2, CI 1.2−3.1); respiratory disease (B = 1.7, CI 0.5−2.8); American Society of Anesthetists’ (ASA) classification>Class 2 (B = 1.5, CI 0.4−2.5); splenic flexure mobilized (B = 1.4, CI 0.5−2.3); private hospital (B = 1.4, CI 0.3−2.5).

Conclusions:  Together these factors accounted for only a fifth of the variability in length of stay and few, except possibly ASA, were susceptible of interventions that might reduce stay. Postoperative morbidity, which is largely unpredictable, remains the major cause of prolonged hospital stay.
Priority assessment of patients for elective general surgery: game on?
Authors: MacCormick Andrew D. , Tan Chuan P. , Parry Bryan R.
Published: December 2004

Background:  Clinical priority assessment criteria (CPAC) are used to generate a score by which patients are prioritized and rationed for elective surgery. It is widely believed that surgeons elevate scores to ensure their patients’ acceptance for elective surgery, colloquially called gaming. The purpose of the present paper was therefore to investigate whether there was a temporal trend to an increase in the assigned priority score from the inception of CPAC to the present.

Methods:  Priority and weighted inlier equivalent separations (WIES) scores between 23 April 1999 and 23 July 2002 were collected for elective general surgical cases at Auckland Hospital. A total of 5440 cases was retrospectively analysed using multiple regression techniques. Priority score was included as the dependent variable and time as an independent variable. Any change in case complexity over that period was accounted for by including the WIES score as a covariate. Multiple regression was undertaken for the combined surgeons and for individuals.

Results:  The combined model was statistically significant but accounted for only 17% of the priority score variance. An increase of one WIES unit leads to an increase of 2.7 in priority score (P = 0.0001). The relationship of priority score with time was dependent on the surgeon performing the prioritization. However, only half the surgeons had individual models that indicated gaming.

Conclusions:  The results show that gaming is occurring but that not all surgeons participate in this. The difference between surgeons’ participation in gaming is a potential source of practice variation in the prioritization process.
Role of endoscopic ultrasonography in preoperative staging of gastric carcinoma
Authors: Javaid Gul , Shah Omar J. , Dar Manzoor A. , Shah Parveen , Wani Nazir A. , Zargar Showkat A.
Published: December 2004

Background:   Preoperative staging of tumour extent in upper gastrointestinal malignancy greatly facilitates planning of therapy. The present study was undertaken to see whether preoperative endoscopic ultrasonography (EUS) accurately predicts the tumour stage in gastric carcinoma.

Methods:  Endoscopic ultrasonography was performed preoperatively on 112 patients with gastric cancer. All 112 patients underwent surgery. The results of EUS were compared with postoperative histological staging.

Results:  Endoscopic ultrasonography was correct in determining the primary tumour (T) and regional lymph node (N) staging in 83.0% and 64.2% of patients, respectively. EUS was correct in determining the absence of lymph node metastasis in 87.5% but was not reliable in determining metastasis in one to six regional lymph nodes (N1) and metastasis in seven to 15 regional lymph nodes (N2) stages; (61.5% and 33.3%, respectively). Of 26 patients with N1 stage, 10 had false negative results, whereas 11 patients in stage N2 were diagnosed endoscopically as stage N1. The sensitivity and specificity were 67.2% and 89%, respectively. The actual resection rate (75%) was almost identical to the rate predicted preoperatively by EUS (78%).

Conclusion:  Endoscopic ultrasonography staging is the most accurate method for discriminating between potentially resectable (tumour invading lamina propria or submucosa (T1) to tumour that penetrates the serosa (visceral peritoneum) without invading adjacent structures (T3)) and potentially non‐resectable (tumour invading adjacent structures (T4)) cases of upper gastrointestinal cancer.
Implication of intraoperative sentinel node imprint cytology for consent in the SNAC trial
Authors: Bochner Melissa A. , Kollias James , Gill P. Grantley , Farshid Gelareh , Dodd Thomas J.
Published: December 2004

Background:  Women randomized into the sentinel node biopsy‐only arm of the Sentinel Node versus Axillary Clearance Trial require axillary clearance if the sentinel node is unable to be identified, or if the sentinel node contains metastases. The aim of the present study was to determine the likelihood of immediate and delayed axillary clearance in patients in the trial when nodes were subjected to intraoperative imprint cytology.

Methods:  A prospective database for 400 patients with operable breast cancer was analysed to determine the likelihood of lymph node involvement according to tumour size. The ability to successfully remove a sentinel node and the accuracy of intraoperative imprint cytology of sentinel nodes was investigated. These data were used to predict the likelihood of patients proceeding to immediate or delayed axillary clearance.

Results:  The rate of lymph node involvement was 0%, 10%, 30%, and 53% in tumours measuring <5 mm, 6−10 mm, 11−20 mm and 21−30 mm, respectively. A sentinel node was identified in 95% of cases. In a series of 79 consecutive cases using intraoperative imprint cytology, 37% of sentinel nodes containing metastases were identified intraoperatively. The estimated likelihood of undergoing immediate axillary clearance therefore ranges from 5% for tumours <5 mm, up to 24% for tumours 21−30 mm. Similarly the likelihood of delayed clearance ranges from 0% to 32% depending on tumour size.

Conclusions:  It is possible to give detailed and accurate information to patients undergoing sentinel node biopsy about both the risk of lymph node involvement and the likelihood of requiring immediate or secondary axillary clearance.
Oesophagectomy for early adenocarcinoma and dysplasia arising in Barrett's oesophagus
Authors: Thomson Benjamin N. J. , Cade Richard J.
Published: December 2004

Background:  Oesophagectomy for high‐grade dysplasia is controversial.

Methods:  A prospective study was carried out on all patients who presented between 1993 and 2001 with dysplasia or early adeno­carcinoma who were considered fit for surgery. Details of endoscopic biopsies, appearance, surveillance, operative pathology and outcome were recorded.

Results:  Of 18 patients, one had low‐grade dysplasia, six had high‐grade dysplasia and 11 had early adenocarcinoma. No patient had their biopsy diagnosis down‐staged following final pathology, but two patients with high‐grade dysplasia on biopsy were upstaged to adenocarcinoma. Our only death from disease occurred in a 39‐year‐old man who had undergone yearly surveillance for 86 months until adenocarcinoma was confirmed. There was no operative mortality.

Conclusion:  Oesophagectomy for early adenocarcinoma and dysplasia in Barrett's oesophagus can be done with acceptable rates of mortality and morbidity. Surveillance until adenocarcinoma is confirmed does not guarantee curable disease.
Improved design knot pusher for laparoscopic extracorporeal suturing
Authors: Barto Walid , Chen Stanley
Published: December 2004

Background:  Reliable instruments are essential for a hassle free laparoscopic operation. We describe a new knot pusher for improved extracorporeal suturing.

Methods:  A new knot pusher was designed and tested in laparoscopic Nissen fundoplication.

Results:  The instrument was used satisfactorily in 13 laparoscopic Nissen fundoplications. There were no complications and the instrument was found, overall, to be superior to the commercially available knot pushers.

Conclusion:  The new knot pusher offers a tailored instrument for extracorporeal knot tying.
Laparoscopic placement of peritoneal dialysis catheters: 7 years experience
Authors: Lu Cu T. , Watson David I. , Elias Tony J. , Faull Randall J. , Clarkson Anthony R. , Bannister Kym M.
Published: December 2004

Background:  Since 1994 we have placed all peritoneal dialysis (Tenckhoff) catheters at our hospital laparoscopically using a technique that incorporates suture fixation into the pelvis. The purpose of this study was to determine the long‐term outcome of this approach.

Method:  Perioperative and follow‐up data for all patients undergoing placement of a peritoneal dialysis catheter at the Royal Adelaide Hospital were collected prospectively and managed on unit specific and hospital wide computerized databases. A total of 148 procedures were carried out in 123 patients from March 1994 to November 2001. Follow‐up ranged from 3 to 68 months (median, 42 months). All procedures were undertaken or supervised by one surgeon, and catheters were routinely sutured into the pelvis at laparoscopy.

Results:  There was no perioperative mortality in this series, and only one catheter could not be placed laparoscopically. This was in a patient with extensive intra‐abdominal adhesions. Mean operative time was 27 min (range, 10−100 min), and mean postoperative stay was 2.8 days (range, 1−12 days). Seven (5%) patients experienced peri/postoperative haemorrhage, and four of these underwent surgical re‐exploration. Twenty‐five (17%) catheters are still used for dialysis. Thirty‐four (23%) catheters were removed when the recipient received a subsequent renal transplant, and 42 (28%) patients died during follow‐up. Forty‐six (31%) patients required catheter revision or removal because of technical problems; 26 (18%) recurrent peritonitis or exit site infection; and 20 (14%) catheter blockage. Twenty‐eight reinsertion procedures were carried out in 25 patients. Ten (7%) patients developed port site hernias at late follow‐up, and required hernioplasty. Catheter migration leading to malfunction (poor drainage) occurred in eight (5%) patients only.

Conclusions:  Laparoscopic placement of peritoneal dialysis catheters is a safe and effective procedure. The majority of patients will dialyse successfully using this technique. Suturing the catheter tip into the pelvis is associated with a low rate of catheter migration.
Transfer of one fascicle of ulnar nerve to functioning free gracilis muscle transplantation for elbow flexion
Authors: Sungpet Adisak , Suphachatwong Chanyut , Kawinwonggowit Viroj
Published: December 2004

Background:  In brachial plexus injury, elbow flexion is the first priority in reconstruction. Neglected cases need functioning free muscle transplantation that requires the donor nerve to supply the transplanted muscle. The purpose of this study was to investigate the effects and results of transferring one fascicle of the ulnar nerve to the transplanted gracilis muscle.

Methods:  One woman and two men with neglected avulsions of the C5,C6 roots of the brachial plexus underwent free gracilis muscle transfer for elbow flexion. One fascicle of the ulnar nerve was used as the donor nerve.

Results:  The mean period of follow‐up was 33.3 months. The average reinnervation time of gracilis muscle was 3.7 months. At the final examination, the mean strength of elbow flexion was 4.3 kgf. The grip strength, moving two‐point discrimination and the strength of the wrist volar flexion on the affected side was not worse than before surgery in any patient at the last follow‐up examination.

Conclusions:  A fascicle of the ulnar nerve can be one of the most effective options for functioning free muscle transplantation for elbow flexion.
Diabetes and the outcome of infrainguinal bypass for critical limb ischaemia
Authors: AhChong Ah Kian , Chiu Kai Ming , Wong Maket Wai Chun , Hui Hiu Kit , Yip Andrew Wai Chun
Published: December 2004

Aim:  To examine the influence of diabetes mellitus (DM) on the outcome of infrainguinal bypass operations performed for critical foot ischaemia in Chinese patients.

Methods:  A prospective audit of 265 consecutive infrainguinal bypass operations.

Results:  Diabetic patients suffered more frequently from ischaemic heart disease (48%vs 25%, P= 0.001) and tissue loss (90%vs 79%, P = 0.01) at presentation. Cigarette smoking was more prevalent in the non‐diabetic (NDM) group (72%vs 51%, P = 0.001). Arterial segments distal to the common femoral artery were more often used as inflow to bypass graft in DM patients (36%vs 22%, P = 0.02). Operative mortality (seven DMvs one NDM, P = 0.19). Early graft failure (7% in DM group vs 10% in NDM group, P = 0.24), wound infection rate (24% in DM group vs 17% in NDM group, P = 0.21), early limb loss (9% in DM group vs 6% in NDM group, P = 0.66) were comparable. However, hospital mortality was higher in DM patients (8%vs 1%, P = 0.04). DM patients more frequently required further surgical debridement postoperatively (20%vs 9%, P = 0.04). Long‐term, patient survival was inferior in the DM group (43% NDM vs 33% DM at 5 years, P = 0.03). Primary graft patency (46% DM vs 34% NDM at 4 years P = 0.19), secondary graft patency (57% DM vs 47% NDM at 4 years P = 0.14) and limb salvage rate (78%vs 81% at 5 years, P = 0.79) were comparable.

Conclusion:  Diabetes mellitus adversely affects hospital mortality and long‐term survival. Graft patency and limb salvage are not compromised by the presence of DM.
The fine structure of the muscle system in the female of the orthonectid Intoshia variabili (Orthonectida)
Authors: Slyusarev George S.
Published: December 2004

The contractile system of the female Intoshia variabili (Orthonectida) consists of smooth muscles. The attachment of the longitudinal muscle fibres at the anterior and the posterior tips of the body is rather peculiar, accomplished by means of elongated terminal muscle cells piercing through several ciliated cells. In the last ciliated cell, the muscle cell invaginates the ciliated cell basal membrane almost up to the ciliated cell surface. Here, around the protrusion terminus, there is an electron‐dense zone in contact with the cilia rootlets.
Chondrocranial, hyobranchial and internal oral morphology in larvae of the basal bufonid genus Melanophryniscus (Amphibia: Anura)
Authors: Larson Peter M. , De Sá Rafael O. , Arrieta Diego
Published: December 2004

Melanophryniscus
is a genus of small toads inhabiting the southern portion of South America. This genus is considered basal within the family Bufonidae. Data on larval chondrocranial morphology do not exist for the genus and larval internal oral anatomy has only been described for a single species. Here, we describe chondrocranial and internal oral morphology in
Melanophryniscus montevidensis
,
M. orejasmirandai
and
M. sanmartini
. Chondrocranial morphology is similar among the species examined. Comparisons with other bufonids and with outgroup taxa suggest that the following chondrocranial characters may represent synapomorphies for the Bufonidae: free (or absent) ceratobranchial IV, a reduced or absent larval crista parotica, the lack of a larval otic process, and late development of thin, poorly chondrified orbital cartilages. The presence of an elongated processus anterior dorsalis of the suprarostral alae and the absence of a chondrified commissura quadratoorbitalis appear to be unique in
Melanophryniscus
among bufonids. Internal oral anatomy is conserved in
Melanophryniscus , and among bufonids in general.
The complex relationship between smoking in pregnancy and very preterm delivery
Authors: Burguet Antoine , Kaminski Monique , Abraham‐Lerat Laurence , Schaal Jean‐Patrick , Cambonie Gilles , Fresson Jeanne , Grandjean Hélène , Truffert Patrick , Marpeau Loïc , Voyer Marcel , Rozé Jean‐Christophe , Treisser Alain , Larroque Béatrice ,   EPIPAGE Study Group,   The EPIPAGE Study Group (listed in the Appendix)
Published: December 2004

Objective  To assess the relationship between cigarette smoking during pregnancy and very preterm births, according to the main mechanisms of preterm birth.

Design  Case–control study (the French Epipage study).

Setting  Regionally defined population of births in France.

Population  Eight hundred and sixty‐four very preterm live‐born singletons (between 27 and 32 completed weeks of gestation) and 567 unmatched full‐term controls.

Methods  Data from the French Epipage study were analysed using a polytomous logistic regression model to control for social and demographic characteristics, pre‐pregnancy body mass index and obstetric history. The main mechanisms of preterm delivery were classified as gestational hypertension, antepartum haemorrhage, premature rupture of membranes, spontaneous preterm labour and other miscellaneous mechanisms.

Main outcome measures  Odds ratios for very preterm birth for low to moderate (1–9 cigarettes/day) and heavy (≥10 cigarettes/day) maternal smoking in pregnancy, estimated according to the main mechanisms leading to preterm birth.

Results  Smokers were more likely to give birth to very preterm infants than non‐smokers [adjusted odds ratio (aOR) 1.7, 95% confidence interval (CI) 1.3–2.2]. Heavy smoking significantly reduced the risk of very preterm birth due to gestational hypertension (aOR 0.5, 95% CI 0.3–1.0), whereas both low to moderate and heavy smoking increased the risk of very preterm birth due to all other mechanisms (aOR between 1.6 and 2.8).

Conclusion  These data from the Epipage study show that maternal smoking during pregnancy is a risk factor for very preterm birth. The impact of maternal smoking on very preterm birth appears to be complex: it lowers the risk of very preterm birth due to gestational hypertension, but increases the risk of very preterm birth due to other mechanisms. These findings might explain why maternal smoking is more closely related to preterm birth among multiparous women than among nulliparous women.
Breastfeeding, Bed‐Sharing, and Infant Sleep
Authors: Ball Helen L.
Published: December 2004

Abstract:  Background:  Expectations for infant sleep development and for the appropriate degree of parental proximity for infant sleep are culturally weighted and historically shifting aspects of parenting behavior, and are known to affect breastfeeding prevalence and duration. This paper examined how new parents managed night‐time feeding in the first 4 months, with a particular focus on the relationship between breastfeeding, infant sleep location, and sleep bout duration.

Methods:  Sleep logs and semistructured interviews were used with a sample of 253 families in North Tees, United Kingdom, to explore how parents responded to their infant's sleep patterns, how breastfeeding parents managed night‐time feeding, and whether bed‐sharing was a common strategy.

Results:  A clear relationship between breastfeeding and parent‐infant bed‐sharing was demonstrated. Some evidence indicated that bed‐sharing may promote breastfeeding.

Conclusions:  An understanding of the role of infant feeding practice on infant sleep and parental caregiving at night is a crucial element in breastfeeding promotion and enhancement of infant health. Health professionals should discuss safe bed‐sharing practices with all parents. (BIRTH 30:3 September 2003)
Selected Coping Strategies in Labor: An Investigation of Women's Experiences
Authors: Spiby Helen , Slade Pauline , Escott Diane , Henderson Beverley , Fraser Robert B.
Published: December 2004

Abstract:  Background:  Antenatal education classes offer women information about labor and birth and ways of coping with pain and emotional distress. The purpose of this paper was to describe women's experiences of using, starting, and discontinuing three coping strategies in labor that were taught in antenatal education classes.

Methods:  An exploratory research design was used in which 121 women were interviewed within 72 hours of the birth of their first child. Information was obtained on why women initiated and discontinued their use of three coping strategies (breathing technique, postural changes, relaxation technique) and the reported effects of use.

Results:  The effects of the coping strategies investigated varied widely among participants. Common aspects of care, changes of environment, and use of pharmacological pain relief affected women's discontinuation of coping strategies.

Conclusions:  The implications of study findings for clinical practice include the need for caregivers to provide women with accurate information about the effects of coping strategies and to be alert to aspects of care that may disrupt women's use of strategies. (BIRTH 30:3 September 2003)
Commissural Dehiscence and Pannus Formation of Porcine Heart Valve Bioprostheses
Authors: Kimura Michio , Iwakuma Akio , Morishige Noritsugu , Nakamura Katsuhiko , Tachikawa Yutaka , Shibano Ryuichi , Iwahashi Hidehiko , Zaitsu Ryuji , Motomura Tadashi , Takeuchi Kazuma , Tashiro Tadashi , Kitasato Katsushi
Published: December 2004

Abstract:  From May 1976 to June 2001, 95 porcine heart valve bioprostheses (BPs) were explanted. Among them, 85 prostheses were available for an analysis of structural valve deterioration (SVD). There were 32 Hancock (H) BPs and 53 Carpentier‐Edwards (CE) BPs, with a mean implantation duration of 12 ± 3.5 and 11.0 ± 4 years, respectively. There were two extraordinary complications. One was commissural dehiscence (CD) of the CEBPs in 10/53 cases (18.9%), with a mean duration of 12.7 ± 2.7 years. This was not observed in the HBPs. The other was pannus formation in both BPs. In the mitral position, it was 25/32 (78.1%) in HBPs and 37/53 (69.8%) in CEBPs. In the aortic position, it was 4/32 (1.3%) in the HBPs and 11/53 (20.8%) in the CEBPs. We conclude that CD could not be diagnosed preoperatively and anticoagulation is therefore indicated to prevent pannus formation of such prostheses, particularly in those located in the mitral position.
Measurement of the Closing Behavior of the Björk‐Shiley Monoleaflet Mechanical Heart Valve with an Electrohydraulic Total Artificial Heart
Authors: Lee Hwansung , Tsukiya Tomonori , Homma Akihiko , Taenaka Yoshiyuki , Tatsumi Eisuke , Takano Hisateru
Published: December 2004

Abstract:  When cavitation occurs near a material surface of a mechanical heart valve (MHV), pits on the surface of the MHV and hemolysis are caused. Therefore, it is very important to investigate the possibility of the occurrence of cavitation in an MHV. To study the possibility of cavitation occurrence in a 25 mm Björk‐Shiley monoleaflet, we analyzed the closing behavior of these valves. The closing event of these valves in the mitral and aortic positions was simulated in an electrohydraulic total artificial heart with a stroke volume of 100 ml. Tests were conducted under physiologic pressures at heart rates of 50, 60, 70, and 80 beats/min with cardiac outputs of 4.8, 5.9, 7.0, and 8.1 L/min, respectively. The disk‐closing behavior was measured by a laser displacement sensor. The closing behaviors were investigated with various cardiac outputs and gravity direction. The maximum velocities of the aortic valve ranged from 0.8 to 0.9 m/s, and for the mitral valve ranged from 1.48 to 1.6 m/s. In aortic position valves, the maximum closing velocities were less than the reported cavitation thresholds, but the maximum closing velocities of the mitral valve were similar to the cavitation threshold. Therefore, we suggest that there should be the possibility of cavitation occurrence in the mitral valve of an electrohydraulic total artificial heart.
Mechanical Properties of Various Z‐Stent Designs: An Endovascular Stent‐Grafting Perspective
Authors: Bashar Abul Hasan Muhammad , Kazui Teruhisa , Washiyama Naoki , Terada Hitoshi , Yamashita Katsushi , Haque Mohammad E.
Published: December 2004

Abstract:  Purpose: To comparatively assess the mechani‐cal behavior of various clinically relevant Z‐stent designs. Methods: A total of 16 Z‐stents of original, biliary, spiral, and double‐skirted designs (n=4 for each) were constructed using similar specifications for all. Stents were then evaluated for stiffness, snap opening force (SOF), flexibility, and displacement force using a novel tensiometer. Differences among the stents were determined using statistical methods. Stents explanted from dog aorta after a mean follow‐up of 13 months were examined under a scanning electron microscope for surface defects. Results: Forces required for about 50% reduction in diameter were 1.88 ± 0.16 N, 3.81 ± 0.21 N, 2.76 ± 0.22 N, and 3.35 ± 0.19 N for original, biliary, spiral, and skirted designs, respectively. Differences among the four designs were statistically significant at almost all points of measurement (P < 0.0001). Biliary and skirted designs showed higher SOF values in the early measurements. Stents explanted from dog aorta after a mean duration of 13 months showed no obvious corrosion or breakage in the wire struts. Conclusions: Significant differences exist among the various Z‐stent designs in terms of their mechanical properties. Understanding them should help to select the appropriate stent for a given lesion. 316L stainless steel shows a favorable long‐term tissue interaction.
Ammonium Detoxification Performed by Porcine Hepatocyte Spheroids in a Bioartificial Liver for Pediatric Use: Preliminary Report
Authors: Lorenti Alicia , Barbich Mariana , Santibáñes Martin de , Ielpi Marcelo , Vazquez Juan Carlos , Sorroche Patricia , Argibay Pablo
Published: December 2004

Abstract: Bioartificial liver devices are alternative therapies for patients suffering from acute hepatic failure or metabolic defects. Here, we show a bioartificial device, developed with a cartridge used for pediatric hemofiltration and spheroids of porcine hepatocytes housed in the extracapillary space of the cartridge. The cartridge was attached to a robotic arm that supplied a continuous, oscillatory movement. It was connected through the capillary circulation to a neonatal membrane oxygenator contain‐ing human blood supplemented with ammonium and diazepam. A decrease in ammonium concentration was observed, reaching an almost 70% decrease upon 9 h of operation. In addition, urea was detected and diazepam metabolism proved from the fourth hour of operation. It is worth mentioning that the system described was assembled with commercially available components for current clinical use. The setup may be done in a short period, thus eliminating long‐term culture times and the need for cell anchoring to matrices.
Magnetically Suspended Centrifugal Blood Pump with an Axially Levitated Motor
Authors: Masuzawa Toru , Ezoe Shiroh , Kato Tsuyoshi , Okada Yohji
Published: December 2004

Abstract: The longevity of a rotary blood pump is mainly determined by the durability of its wearing mechanical parts such as bearings and seals. Magnetic suspension techniques can be used to eliminate these mechanical parts altogether. This article describes a magnetically suspended centrifugal blood pump using an axially levitated motor. The motor comprises an upper stator, a bottom stator, and a levitated rotor‐impeller between the stators. The upper stator has permanent magnets to generate an attractive axial bias force on the rotor and electric magnets to control the inclination of the rotor. The bottom stator has electric magnets to generate attractive forces and rotating torque to control the axial displacement and rotation of the rotor. The radial displacement of the rotor is restricted by passive stability. A shrouded impeller is integrated within the rotor. The performance of the magnetic suspension and pump were evaluated in a closed mock loop circuit filled with water. The maximum amplitude of the rotor displacement in the axial direction was only 0.06 mm. The maximum possible rotational speed during levitation was 1,600 rpm. The maximum pressure head and flow rate were 120 mm Hg and 7 L/min, respectively. The pump shows promise as a ventricular assist device.
Influence of Different Heparin Concentrations on the Results of In Vitro Investigations in Plasmaseparation Technology Using Capillary Membrane Filters
Authors: Unger Juliane Katharina , Haltern Claudia , Dohmen Bernd , Rossaint Rolf
Published: December 2004

Abstract: Capillary membrane filters are devices commonly used for plasmapheresis and recirculating detoxification systems, including plasmaseparation units. Besides clinical trials and case reports, research on plasmafiltration techniques is carried out using in vitro systems. Notably, such hemoperfused in vitro systems require anticoagulation protocols suitable for investigating the clearance performance and hemocompatibility of a plasmafilter. This study analyzes how different heparin concentrations affect filtration performance and the hemocompatibility under conditions typically employed during in vitro experiments. Porcine blood from healthy slaughtered animals was used in an in vitro circuit. The blood collecting system was primed with heparin. Depending on the study group, blood was anticoagulated with either 2.5 IU/ml or 5 IU/ml heparin. The filters were n=10 PF1000N (effective membrane surface: 0.15 m2). For each experiment, the maximal permissible flow rate was established by determining the point where spontaneous hemolysis occurred and/or pressure values exceeded the highest limit of the pressure units on the apheresis monitor. Sieving coefficients of ten parameters, platelet counts, and coagulation patterns were determined at the lowest and highest blood flow (Qb) and filtration rates (Qf). Except for the activated clotting time (ACT), both anticoagulation protocols caused the blood to respond to its exposition to the plasmafilters concerning the activation and inhibition of the coagulation system. A significant decrease in platelet counts did not occur. There were sporadic differences in sieving properties between the groups. However, heparinization with 2.5 IU/ml resulted in unreproducible flow rate profiles, and pressure levels were higher than in the group with 5 IU/ml heparin. Compared to heparinization at 2.5 IU/ml, higher levels of heparinization stabilize rheological properties of the blood, and thereby increase the reliability of data obtained from plasmafiltration experiments carried out in vitro.
Release of (1→3)‐β‐D‐Glucan from Depth‐type Membrane Filters and Their In Vitro Effects on Proinflammatory Cytokine Production
Authors: Ohata Atsushi , Usami Makoto , Horiuchi Takashi , Nagasawa Koichi , Kinoshita Keiko
Published: December 2004

Abstract:  To clarify the origin of (1→3)‐β‐D‐glucan in blood products and assess the biological activity of filter extracts, we evaluated (1→3)‐β‐D‐glucan extraction from depth filters used to process blood products and their in vitro effects on proinflammatory cytokine production from macrophages. Cellulose or nylon filters were analyzed for (1→3)‐β‐D‐glucan using the Fungitec G test. To evaluate the biological activity of the filter extracts, Mono Mac 6 cells (a human macrophage cell line) were cultured with filter extracts with or without lipopolysaccharide, and tumor necrosis factor‐alpha (TNF‐α) and interleukin‐1 beta (IL‐1β) concentrations in the culture media were measured. (1→3)‐β‐D‐Glucan was released from seven cellulose filters but the nylon filter level was undetectable. Proinflammatory cytokine production ranged from 74.3% to 119.0% of the control for TNF‐α and 81.2% to 115.9% for IL‐1β. TNF‐α and IL‐1β levels were low without lipopolysaccharide. The data indicate that (1→3)‐β‐D‐glucan in blood products is contaminated with the depth filters and that these filter extracts modulate proinflammatory cytokine production from macrophages.
Bioartificial Liver Inoculated with Porcine Hepatocyte Spheroids for Treatment of Canine Acute Liver Failure Model
Authors: Chen Zhong , Ding Yitao , Xu Qingxiang , Yu Decai
Published: December 2004

Abstract: The aim of this study was to evaluate a novel bioartificial system in a canine model of acute liver failure. An acute liver failure model in canines was induced by an end‐side portocaval shunt combined with common bile duct ligation and transection. The bioartificial liver system, which utilized blood perfusion through a hollow fiber bioreactor from BIOLIV A3A inoculated with 1.0 − 3.1 × 1010 porcine hepatocyte spheroids, was developed for the treatment of acute liver failure. Sixteen acute liver failure model canines were divided between a group treated with bioartificial liver (n=8) and a control group (n=8) for 5 h. Blood alanine aminotransferase (ALT), alkaline phosphatase (AKP), total bilirubin (TBi), direct bilirubin (DBi), prothrombin time (PT), ammonia levels, and the ratio of branched chain to aromatic amino acids (Fischer's ratio) were determined. ALT, AKP, TBi, DBi, and ammonia levels were significantly elevated, PT was significantly prolonged, and Fischer's ratio decreased significantly in the canine model of the two groups on day 14 after operation compared to baseline. There were no significant differences between the two groups in laboratory data before treatment. In canines treated with the bioartificial liver system, ALT, AKP, TBi, DBi, and ammonia levels decreased significantly, PT was significantly shortened, Fischer's ratio was significantly elevated after treatment, and the survival rate by day 7 after treatment was 100%. In canines in the control group, on the other hand, there were no significant differences in ALT, AKP, TBi, DBi, PT, and ammonia levels between pretreatment and posttreatment, though these indices decreased to a slight degree after treatment. The survival rate by day 7 after treatment was 62.5% in the control group. Fischer's ratio decreased after treatment. ALT, AKP, TBi, DBi, PT, and ammonia levels in the bioartificial liver system group were lower, and Fischer's ratio and survival rate were higher than those in the control group after treatment. These results indicate that the novel bioartificial liver system we developed has a significant impact on the course of canine acute liver failure model and has potential advantages for clinical use in patients with acute liver failure.
Liposomal Entrapment of Cefoxitin to Improve Cellular Viability and Function in Human Saphenous Veins
Authors: Park Jong‐Chul , Suh Hwal , Sung Hak‐Joon , Han Dong‐Wook , Lee Dong Hee , Park Bong Joo , Park Young Hwan , Cho Bum Koo
Published: December 2004

Abstract: Liposomal cefoxitin was prepared and applied to the pretreatment of human saphenous vein (HSV) for implantation. The possible use of liposomal cefoxitin to improve cellular viability and function and to maintain its potential sterilization effect was investigated. Entrapment efficiency and size distribution of liposomal cefoxitin were 75.7% and 652 ± 75.7 nm, respectively. The weight ratio between cefoxitin and liposome was calculated at 1 : 40.6. When cefoxitin was entrapped with liposome, the released amount of cefoxitin was not affected by temperature conditions (37°C, 25°C, and 4°C). The amount of free cefoxitin present in HSV reached 59% at 0.5 h and gradually decreased with time, while liposomal cefoxitin showed a maximum amount (63%) at 1.5 h, indicating that liposomal cefoxitin seemed to control the initial amount of cefoxitin present in HSV. Liposomal cefoxitin showed better viabilities of whole cells and endothelial cells dissociated from HSV than free cefoxitin and remarkably superior function of endothelial cells, as determined by Griffonia simplicifolia agglutinins‐fluorescein isothiocyanate/propidium iodide double‐staining methods combined with flow cytometry and endothelial nitric oxide synthase assay, respectively. In terms of sterilization effect, there was no significant difference between liposomal cefoxitin and free cefoxitin. These results suggest that liposomal entrapment of cefoxitin could improve cellular viability and functions and maintain the original sterilization effect.
Oxidant Stress in Hemodialysis Patients: What Are the Determining Factors?
Authors: Ward Richard A. , McLeish Kenneth R.
Published: December 2004

Abstract: Oxidant stress contributes to morbidity in hemodialysis patients. Three possible causes of oxidant stress have been suggested: the uremic state, the dialyzer membrane, and bacterial contaminants from the dialysate. Oxidant stress occurs in uremia before dialysis therapy is initiated, as evidenced by increased production of reactive oxygen species, increased levels of oxidized plasma proteins and lipids, and decreased antioxidant defenses. It has been proposed that increased production of reactive oxygen species during hemodialysis is also an important contributor to oxidant stress. Hemodialysis is associated with a transient increase in production of reactive oxygen species, particularly with cellulose membranes. In addition, surveys have shown widespread contamination of dialysate by endotoxin, which may cross membranes and prime production of reactive oxygen species by phagocytic cells. Recent studies, however, show a decrease in protein oxidation from pre‐ to post‐dialysis and a normalization of neutrophil reactive oxygen species production. Taken together, these data suggest that uremia, per se, is the most important cause of oxidant stress in hemodialysis patients. Dialysate quality may also contribute to oxidant stress, but evidence that the dialyzer membrane plays a role is weak.
Ultrafiltration and Dry Weight—What Are the Cardiovascular Effects?
Authors: Stegmayr Bernd G.
Published: December 2004

Abstract: Long‐term prognosis in dialysis is poor compared to that in healthy control persons. A worsening of the prognosis is noted especially for patients who at initiation of dialysis have congestive heart failure, ischemic heart disease, or left ventricular dysfunction or hypertrophy. This is the main reason that cardiovascular causes are the most common for morbidity in these patients. The weight obtained when normal urine output is present is the dry weight. With reduced ability to excrete the volume by the kidneys in end‐stage renal disease (ESRD), the body will retain water and the patient will gain weight. This extra weight is due to volume overload. While volume overload may induce a rise in blood pressure, if the heart is in acceptable condition, a fast removal of fluid by ultrafiltration (UF) during dialysis may instead cause hypotension. Ultrafiltration failure in peritoneal dialysis (PD) patients may lead to successive water retention and overhydration with subsequent cardiac failure, while volume overload may occur over a few days in hemodialysis (HD) patients. Anemia or even too‐high hematocrit may impair cardiac function further and worsen conditions caused by wrong dry weight. Thus, during long‐term and sustained volume overload, left ventricular (LV) hypertrophy will occur in an eccentric manner. A sustained overload then may lead to cell death and LV dilatation and, eventually, systolic dysfunction. Once a severe left ventricular dilatation has developed, the blood pressure may decrease during volume overload. A worsened prognosis is seen if malnutrition and low albumin levels are present. Volume overload necessitates ultrafiltration to achieve dry weight. Thereby, volume contraction contributes to exaggerated stimulation of or response to activation of the RAS and alpha‐adrenergic sympathetic systems. If ultrafiltration goes beyond these compensatory mechanisms, hypotension will occur and increase the risk for hypoperfusion of vital organs. Such episodes may cause cardiac morbidity, aspiration pneumonia, vascular access closure, or neurological complications (seizures, cerebral infarction), besides a more rapid lowering of residual renal function. Preventive measures are, first, finding the right dry weight; second, minimizing interdialytic weight gain; third, optimizing the target for hemoglobin (110–120 g/l); fourth, lowering dialysate calcium (1.25 mmol/l); and fifth, eventually using higher dialysate potassium if long dialyses are performed.
Nutritional Effect of Dialysis Therapy
Authors: Sanaka Tsutomu
Published: December 2004

Abstract: The prognosis of patients with end‐stage renal disease has been improved by the recent remarkable advances in medical and engineering technology. However, there are still many unsolved problems in the clinical field. One of the problems is an intractable malnutrition characterized by clinical manifestations including hypoproteinemia and decrease in muscular volume, which is associated with deterioration in the quality of the patient's life. Malnutrition in hemodialysis patients involves abnormal energy metabolism and aberrant amino acid metabolism. In the most malnourished patients, immunodefense mechanisms and homeostasis are disrupted, greatly influencing the prognosis. Moreover, when the performance of dialyzer used is too high, the dialysis treatment might remove a necessary nutrient for the patient. There is also a possibility that the protein catabolism is accelerated when the biocompatibility is inferior. On the other hand, in malnutri‐tion, the circulating level of insulin‐like growth factor‐1 (IGF‐1) falls while the level of insulin‐like growth factor binding protein‐1 (IGFBP‐1) is remarkably increased. It has been recognized that IGF‐1 and IGFBP‐1 are indicators reflecting the initiation of a malnutritional state in patients with chronic renal failure, although there are many indicators such as albumin, prealbumin, and anthropometric measurement for nutritional assessment. We have suggested that r‐hGH and IGF‐1 improve the malnutritional state by alleviating hypoproteinemia and abnormality of serum amino acid profile in uremic patients on hemodialysis. The serum IGF‐1/IGFBP‐1 ratio is useful not only as a nutritional parameter but also as a predicting index of responsiveness to r‐hGH. It is necessary to examine the problem from various angles to improve malnutrition in the dialysis patient, while considering the above mentioned.
Is Serum Albumin a Marker of Nutritional Status in Hemodialysis Patients without Evidence of Inflammation?
Authors: Santos Nelma Scheyla José dos , Draibe Sergio Antonio , Kamimura Maria Ayako , Canziani Maria Eugênia Fernandes , Cendoroglo Miguel , Júnior Alexandre Gabriel , Cuppari Lilian
Published: December 2004

Abstract:  Hypoalbuminemia, a strong predictor of morbidity and mortality in hemodialysis patients, can be a consequence of a combination of malnutrition and inflammatory reactions. The purpose of this study was to analyze serum albumin as a marker of nutritional status in maintenance hemodialysis patients with no signs of inflammation. In a cross‐sectional study, we selected 40 stable hemodialysis patients with normal levels of C‐reactive protein (<0.8 mg/dL). The patients were classified as well nourished (65%) or malnourished (35%) according to the subjective global assessment. No significant differences were observed in serum albumin concentrations (immunoturbidimetric method) between well‐nourished (4.3 ± 0.3 g/dL) and malnourished (4.0 ± 0.5 g/dL) patients, and the mean values were within the normal range in both groups. Albumin was inversely correlated with age (n=40; r=−0.32; P=0.02) and directly with energy intake (n=28; r=0.43; P=0.04). In this study, serum albumin did not discriminate well‐nourished and malnourished hemodialysis patients without evidence of inflammation.
Noninvasive Assessment of Hemodynamic Parameters in Experimental Stenosis of the Ascending Aorta
Authors: Pires Mara D. , Salemi Vera M.C. , Cestari Idágene A. , Picard Michael H. , Leirner Adolfo A. , Mady Charles , Cestari Ismar N.
Published: December 2004

Abstract:  We sought to noninvasively evaluate left ventricular (LV) function after cardiac hypertrophy induced by experimental stenosis of the ascending aorta. Male Wistar rats (70–90 g) underwent ascending aorta constriction by the surgical placement of a titanium clip (n=5) or sham operation (n=6). High‐resolution bidimensional, pulsed‐wave Doppler (PWD) and pulsed‐wave tissue Doppler imaging (TDI) were performed 22 weeks after surgery. PWD was used to obtain mitral flow velocities, and TDI was used to obtain velocities along the septal mitral annulus and LV posterior wall. Clip placement produced myocardial hypertrophy with decreased systolic myocardial peak velocity in both the long and short axes. Increased myocardial mass, that is, posterior wall and septal thickness, was indicative of ventricular remodeling. Diastolic dysfunction was observed, with an increased early to late ratio of mitral velocities and increased left atrium dimension, consistent with a left ventricular restrictive filling pattern.
Asymptomatic Occlusive Lesions of Cerebral Arteries in Japanese Hemodialysis Patients
Authors: Nakatani Tatsuya , Naganuma Toshihide , Uchida Junji , Masuda Chikayoshi , Wada Seiji , Sugimura Takeshi , Sugimura Kazunobu
Published: December 2004

Abstract: While cerebrovascular diseases (CVD) are very common in hemodialysis (HD) patients, the prevalence and risk factors of asymptomatic occlusive lesions (AOL) of cerebral arteries in HD patients have not yet been elucidated. We performed cerebral magnetic resonance angiography (MRA) on 123 HD patients without symptomatic cerebrovascular disease and on 52 control subjects. On the basis of these images, we investigated the prevalence and risk factors of AOL. Stenosis greater than 25% narrowing of the cerebral arteries was found in 27 HD patients. The prevalence of AOL of cerebral arteries in HD patients was significantly higher than in the control group [27 (22.0%) versus 4 patients (7.7%), χ.2=4.2, p=0.0411]. Multiple logistic regression analysis showed that independent risk factors of AOL of cerebral arteries were uremic state, dyslipidemia, and age in all subjects and dyslipidemia and age in HD patients (R.2=0.162, p=0.0004; R.2 =0.138, p=0.0145, respectively). Our findings suggest that chronic renal failure maintained by hemodialysis increases the prevalence of AOL, and that age and dyslipidemia are also significantly associated with AOL in HD patients.