bluuebunny/crossref_metadata_2025 huggingface dataset:
Regeneration of the Junctional Epithelium and Connective Tissue after Transplantation of Detergent-Processed Allo-Teeth
Authors: Inoue M. , Nakamura T. , Shigeno K. , Ueda H. , Tamura N. , Fukuda S. , Liu Y. , Nakahara T. , Toba T. , Yoshitani M. , Iizuka T. , Shimizu Y.
Published: March 2018

The authors have developed a new artificial dental implant and evaluated it in a dog model in terms of its potential to produce: I) regeneration of junctional epithelium; II) regeneration and attachment of connective tissue. The implants were constructed from allo-teeth. We removed the cell components from the periodontal ligaments of these teeth with a detergent (1% TritonX-100); the remaining acellular periodontal ligament acted as an extracellular matrix upon which regeneration and attachment could proceed. We placed 10 of these implants in the just-extracted sites of three beagle dogs. We observed regeneration of both junctional epithelium and connective tissue at all implant sites after 3 months. The connective tissue was attached in all cases. Use of the acellular periodontal ligament as an extracellular matrix may facilitate regeneration of host periodontal ligament tissue, thus contributing to recovery of host immunological defense and long-term oral function.
The Outcome of Patients Presenting with Crush Syndrome after the Marmara Earthquake
Authors: Kazancioğlu R. , Korular D. , Sever M.Ş. , Türkmen A. , Aysuna N. , Kayacan S.M. , Tahin S. , Yildiz A. , Bozfakioğlu S. , Ark E.
Published: March 2018

In this study, we evaluated the clinical and laboratory data of the patients presenting after the Marmara earthquake. Crush syndrome was diagnosed in 60 patients (30 M, 30 F, mean age: 31.3±13.8 years). They were buried under the rubble for a mean period of 12.3±15.1 hours. On admission, 27 patients were oligoanuric and the mean serum creatinine, creatinine phosphokinase and potassium levels were 4.4±3.2 mg/dl, 18453.1±24527.2 IU/L, and 4.9±1.7 mEq/L, respectively. The most frequent site of trauma was the lower extremity. Dialysis treatment was initiated in 40 patients (19 M, 21 F, mean age: 32.7±13.0 years). Mean number of hemodialysis sessions/patient was 8.9±6.8. Nine (23%) patients among the dialyzed and 4 (20%) among the non-dialyzed died leading to an overall mortality of 21.6%. This low mortality rate suggests that the death rate from acute renal failure due to crush syndrome could be decreased by extensive follow-up.
Evaluation of Stress on the Autonomic Nervous System of Patients on Mechanical Circulatory Assist
Authors: Tsutsui T. , Jikuya T. , Shigeta O. , Sakakibara Y. , Terada Y.
Published: March 2018

Purpose

The power density values of high (HF; 0.15 to 0.4 Hz) and low frequency (LF; 0.04 to 0.15 Hz) components of arterial pressure were adopted for evaluation of stress on the autonomic nervous system of patients supported by mechanical circulatory assist.

Methods

Power spectral analysis (PSA) of arterial pressure signals was carried out, and trends in changes in the spectral components were observed in 12 patients on mechanical circulatory support (IABP and/or PCPS) and without the support (n=10).

Results

The normalized LF was depressed initially and increased gradually in both groups of patients except for four patients on mechanical circulatory assist. Three patients among them consequently died.

Conclusions

Depressed LF represented marked stress on ANS and prolongation of the depression was related to poor outcome of patients. PSA of systemic blood pressure offers a reasonable tool for evaluation of stress on the ANS and for prediction of the prognosis of patients with circulatory assist devices.
Tissue Engineering of the Small Intestine by Acellular Collagen Sponge Scaffold Grafting
Authors: Hori Y. , Nakamura T. , Matsumoto K. , Kurokawa Y. , Satomi S. , Shimizu Y.
Published: March 2018

Tissue engineering of the small intestine will prove a great benefit to patients suffering from short bowel disease. However cell seeding in tissue engineering, such as fetal cell use, is accompanied by problems of ethical issues, rejection, and short supply. To overcome these problems, we carried out an experimental study on tissue engineering of the small intestine by acellular collagen sponge scaffold grafting. We resected the 5 cm long jejunum from beagle dogs and reconstructed it by acellular collagen sponge grafting with a silicon tube stent. The graft was covered with the omentum. At 1 month after operation, the silicon stent was removed endoscopically. Animals were sacrificed 1 and 4 months after operation, and were examined microscopically. Neo-intestinal regeneration was observed and the intestinal mucosa covered the luminal side of the regenerated intestine across the anastomosis. Thus, the small intestine was regenerated by tissue engineering technology using an acellular collagen sponge scaffold.
Bidialysis: A new Technique
Authors: Splendiani G. , Zazzaro D. , Tullio T. , Colombo R. , Beciani M. , Violante A.
Published: March 2018

An increase in solute removal, a shorter dialysis session, the patient's well being and the reduction of global costs are the principal aims of the new hemodialysis methods. The simultaneous use of two hemodialyzers in hemodialysis has been experimented by other researchers. Our technique involves the use of two cuprophan hemodialyzers in sequence (double filter system: DFS), each one connected separately to fresh dialysate.

Fifteen symptomatic large patients were treated with DFS and the results were compared to conventional hemodialysis (CHD). After the first hemodialyzer, modification of pH and electrolytes occurred in the plasma composition. In the second hemodialyzer, urea depuration occurred without further significant changes in hydroelectrolytic or acid-basic plasma patterns. The Kt/V increased from 1.10 to 1.29 (18%).

The authors conclude that in DFS there was an advantage in urea clearance, osmolarity stability and reduction of side effects.
Beneficial Clinical Effects of Ozonated Autohemotherapy in Chronically Dialysed Patients with Atherosclerotic Ischemia of the Lower Limbs - Pilot Study
Authors: Tylicki L. , Niewȩgłowski T. , Biedunkiewicz B. , Burakowski S. , Rutkowski B.
Published: March 2018

Ozonated autohemotherapy is a controversial but successful method of treatment, used in particular in European countries. There are many fields in which medical ozone could be of value: treating different infections, immunodeficiency syndromes, neoplasms. Encouraging results have also been achieved in the treatment of atherosclerotic ischemia of the lower limbs. In this preliminary study, the influence of blood ozonation on the intensity of symptoms of ischemia of the lower extremities was analysed among dialysed patients with chronic renal failure. We examined 5 hemodialyzed patients and 7 patients treated with peritoneal dialysis immediately before and after 14 sessions of ozonated autohaemotherapy. Eleven patients (91.6 %) reported a subjective decrease in perceived intensity of ischemic pains, or observed prolongation of intermittent claudication distance. During march tests performed on a treadmill, we found significant prolongation of intermittent claudication distance in all examined patients – 65.6% (mean value, p (≤0.01). Patients treated with peritoneal dialysis achieved much greater improvement than did hemodialyzed patients (165% vs. 42%). We concluded that autohemotherapy with ozone, in a concentration of 34.4 mcg/ml of blood, is safe, easily applied and may be useful In the therapy of atherosclerotic ischemia of lower extremities among dialyzed patients. It could also be a complement to current treatment, especially in cases where the latter has failed.
Oxygen Metabolism under Various bypass flow Conditions during Cardiopulmonary Support in Awake Goats
Authors: Takewa Y. , Tatsumi E. , Taenaka Y. , Takano H.
Published: March 2018

Despite its wide clinical application, patient recovery from cardiopulmonary support (CPS) is not necessarily satisfactory. To clarify what influence CPS has on organ perfusion, we investigated the oxygen metabolism under various bypass flow (BF) conditions in a series of chronic animal CPS experiments.

The CPS system, which consists of a pulsatile ventricular assist device and a compact artificial lung was installed without anesthesia in 6 adult goats weighing 49–51 kg. BF was adjusted stepwise from 0% to 50%, 75%, 90%, and 100% of total systemic blood flow (TSF) by balancing the pulmonary arterial flow. The animals’ TSF and oxygen delivery (DO2) were sufficiently maintained throughout the experiments.

The oxygen consumption (VO2) and the oxygen extraction rate (ExO2) increased from 178 ± 14 to 342 ± 19 ml/min, and from 28 ± 2% to 64 ± 1%, respectively, in proportion to the increase of CPBF dependency from 0% to 100%. The blood lactate level did not change appreciably even at 90% BF from 5.7 ± 0.3 to 11.2 ± 1.2 mg/dl, but drastically elevated to 23.5 ± 4.6 mg/dl at the total bypass. This indicates that CPS leads to a relative lack of oxygen and can induce organ dysfunction due to increasing VO2 and ExO2 in proportion to the increase of BF dependence even if TSF and DO2 are sufficiently maintained.
Hemolysis and Hematology Profile during Perfusion: Inter-Species Comparison
Authors: Mueller X. M. , Tevaearai H. T. , Jegger D. , Tucker O. , Von Segesser L.K.
Published: March 2018

Introduction

Cardiopulmonary bypass components need to be tested on an animal model before their clinical application. Because their weight is similar to that of man, the calf and pig are often used. This study compares the impact of prolonged perfusion on hemolysis and hematology profile in both species.

Methods

Three calves (mean bodyweight: 77.2±4.4 kg) and three pigs (80±5.3 kg) were connected to an extracorporeal circulation circuit by jugular venous and carotid arterial cannulation, with a mean flow rate of 3.5L/min for 6h. After 7 days, the animals were sacrificed. A standard battery of blood samples was taken before, throughout, and 24h, 48h and 7 days after bypass. ANOVA was used for repeated measurements.

Results

Absolute values of red cell count were higher in the calf (p<0.001), while normalized values were higher in the pig (p<0.001). Absolute values of white cell count were higher in the pig, while normalized values diverged toward the end of the perfusion with an increase in the calf and a decrease in the pig (p<0.001). Free plasma Hb and LDH exhibited similar profiles in both groups.

Conclusions

In the setting of prolonged perfusion, species type - bovine or porcine - has an impact on hematology profile, but not on hemolytic parameters. These findings should be taken into account when cardiopulmonary bypass components are tested.
Hydrodynamic Function of a Biostable Polyurethane Flexible Heart Valve after Six Months in Sheep
Authors: Wheatley D.J. , Bernacca G.M. , Tolland M.M. , O'connor B. , Fisher J. , Williams D.F.
Published: March 2018

Survival to six months for sheep with a non-biostable polyurethane mitral heart valve prosthesis has been reported previously, however, with surface degradation and accumulation of calcified fibrin/thrombus that impaired leaflet motion and compromised hydrodynamic function. Newly available biostable polyurethanes may overcome this problem.

Six adult sheep with biostable polyurethane trileaflet heart valve prostheses of documented hydrodynamic performance, implanted in the mitral position, were allowed to survive for 6 months. Explanted valves were photographed, resubmitted to hydrodynamic function testing, and studied by light and electron microscopy.

Explanted valves were structurally intact and differed little in appearance from their preimplant state. Hydrodynamic testing showed no deterioration in pressure gradient or energy losses compared with pre-implant values.

Biostable polyurethanes demonstrated improved blood compatibility leaving leaflets flexible and valve function unimpaired. Biostable polyurethanes may thus improve prospects for prolonged function of synthetic heart valve prostheses.
Characterization of the Distribution of Matter in Hybrid Liver Support Devices where Cells are Cultured in a 3-D Membrane Network or on Flat Substrata
Authors: Catapano G. , Euler M. , Gaylor J.D.S. , Gerlach J.
Published: March 2018

Bioreactors for liver assist tested on small animal models are generally scaled-up to treat humans by increasing their size to host a given liver cell mass. In this process, liver cell function in different culture devices is often established based on the metabolite concentration difference between the bioreactor inlet and outlet irrespective of how matter distributes in the bioreactor.

In this paper, we report our investigation aimed at establishing whether bioreactor design and operating conditions influence the distribution of matter in two bioreactors proposed for liver assist. We investigated a clinical-scale bioreactor where liver cells are cultured around a three-dimensional network of hollow fiber membranes and a laboratory-scale bioreactor with cells adherent on collagen-coated flat substrata. The distribution of matter was characterized under different operating modes and conditions in terms of the bioreactor residence time distribution evaluated by means of tracer experiments and modeled as a cascade of N stirred tanks with the same volume. Under conditions recommended by the manufacturers, matter distributed uniformly in the clinical-scale bioreactor as a result of the intense backmixing (N=1) whereas axial mixing was negligible in the laboratory-scale bioreactor (N=8). Switching from recycle to single-pass operation definitely reduced axial mixing in the clinical-scale bioreactor (N=2). Increasing feed flow rate significantly enhanced axial mixing in the laboratory-scale bioreactor (N=4). The effects of design, operating mode and conditions on matter distribution in bioreactors for liver cell culture suggest that characterization of the distribution of matter is a necessary step in the scale-up of bioreactors for liver assist and when function of liver cells cultured in different bioreactors is evaluated and compared.
The Type II Aachen-Keratoprosthesis in Humans: Case Report of the First Prolonged Application
Authors: Kompa S. , Redbrake C. , Langefeld S. , Brenman K. , Schrage N.
Published: March 2018

Purpose

To improve the prognosis of corneal grafts in silicone-oil filled eyes of patients with severe ocular trauma by a prolonged application of the Type II Aachen-Keratoprosthesis (KPro). This application endeavors to improve post-keratoplasty prognosis by avoiding corneal endothelial dystrophy in the aphakic eye due to contact with silicone oil.

Patient and Procedures

The Aachen-Keratoprosthesis’ haptic was modified to allow tight contact with cells. The Type II Aachen-Keratoprosthesis was then implanted in an 18-year-old male, with previous management of bilateral corneal rupture. Rather than utilize the device as a temporary intraoperative tool, we extended the device's lifespan in the eye.

Main Findings

Following implantation, the patient could see hand movements up to 0.1 with best correction. After 8 weeks, vision decreased and a retroprosthetic membrane proliferated. Upon conjunctival retraction, 3 months after the initial surgery, we excised the prosthesis and performed a re-vitrectomy and corneal grafting. The silicone oil was removed. After eighteen postoperative months, the graft remained clear, the retina was completely attached, and the vision was stable: 0.1 best corrected.

Conclusion

This case reports the prolonged implantation and prospect of the Type II Aachen-Keratoprosthesis to be utilized as a permanent device to restore vision in the near future.
Teletransmission system supporting intensive insulin treatment of out-clinic type 1 diabetic pregnant women. Technical assessment during 3 years’ application
Authors: Ładyzyński P. , Wójcicki J.M. , Krzymień J. , Blachowicz J. , Jóźwicka E. , Czajkowski K. , Janczewska E. , Karnafel W.
Published: March 2018

A telematic system supporting intensive insulin treatment of pregnant type 1 diabetic out-clinic patients was implemented and technical efficiency of the system was evaluated over long-term ambulatory application. The system consists of a patient teletransmission module (PTM) and a central clinical control unit (CCU). The PTM contains a one-box blood glucose meter and electronic logbook, a modem and a dial-up or cellular phone set. The CCU consists of a PC computer with a modem and DIAPRET – an original program designed to monitor the intensive insulin treatment. The system was installed in the Clinic of Gastroenterology and Metabolic Disease, MA Warsaw and was tested for 166 ± 24 days on 15 pregnant type 1 diabetic women. Telemonitoring of the patient data was done automatically. No major technical problems with proper operation or handling of the system was noted. Total effectiveness was 69.3 ± 13.0% and technical effectiveness 91.5 ± 6.1%. The efficacy of the system was not significantly influenced by patient intelligence level, education level or place of residence (p < 0.05). Significant improvement of metabolic control was noted during application of the system. In conclusion, the telematic system we developed and implemented should have a positive influence on the quality of diabetes treatment during pregnancy.
Cascade Filtration (CF) with the Haemonetics MCS+: A New Technical Adaptation
Authors: Valbonesi M. , Bo A. , De Luigi M.C. , Bruni R. , Stura P. , Sanfilippo B. , Varinelli I.
Published: March 2018

CF was introduced in clinical medicine in 1980. Up to now, exclusively two-vein procedures have been carried out with some limitations to expansion of this technique. In this report we describe the very first application of single-needle CF carried out with Haemonetics MCS + apparatus. Twenty procedures were completed without any untoward effect in patients suffering from TTP, post-hepatitic cryoblobulinemia, familial hypercholesterolemia and acute Guillan-Barrè Syndrome. From 1 to 4 sessions were carried out per patient with the expected laboratory and clinical results. The only limit is the procedure time that averages 231 +/- 48 min., approximately 40% longer than two needle procedures.
Blood flow distribution in a polymyxin coated fibrous bed for endotoxin removal. Effect of a new blood path design
Authors: Ronco C. , Brendolan A. , Scabardi M. , Ronco F. , Nakamura H.
Published: March 2018

The analysis of flow distribution in cartridges designed for hemoperfusion is extremely important. Taking advantage of a new imaging technique, based on the analysis of a helical scanner-generated imaging sequence, we studied the blood flow distribution in a series of cartridges for extracorporeal removal of endotoxin. Cartridges with improved design were compared to cartridges with a standard design. The improved design consists in a different structure of the holes of the distributor of the flow within the adsorbent unit. Cartridges were studied in vitro with human blood from voluntary donors at blood flows of 100 and 250 ml/min. The progression of density in specific regions of interest (ROI) was analyzed to detect the distribution of the dye injected in the blood circuit. The study demonstrates that both at 100 ml/min and at 250 ml/min of blood flow, the progression of flow appears more homogeneous in the devices with improved design. In detail, the flow distribution measured by the incremental density values detected in the ROIs of the proximal corners (close to the arterial port) and in the ROIs of the central region of the device (close to the inner wall of the case) displays a significant difference between the standard and the improved device. The ROIs studied in the standard devices display a slower increase in density and significantly lower absolute values expressed in Hounsfield units. The experimental method utilized to analyze flow distribution seems to represent an important means to study the performance and design of this type of device.
Pre and interdialytic acid-base balance in hemodialysis patients
Authors: Graham K.A , Hoenich N.A. , Goodship T.H.J.
Published: March 2018

In an observational study, nine hemodialysis patients using 35 mmol/l bicarbonate dialysate were studied over a 44-hour interdialytic interval. Serum bicarbonate was measured at regular intervals at home and the mean time averaged concentration was 27.0 ± 1.2 mmol/l. Seven of the nine patients showed a slow linear decline in bicarbonate whilst in two patients levels were unchanged. In 8 of 9 patients the average of the post and predialysis bicarbonate accurately predicted the time-averaged (area under the curve) bicarbonate concentration. In addition, pre-dialysis serum bicarbonate was measured in 46 patients after both a 2 and 3-day interdialytic interval. The serum bicarbonate was significantly lower after the 3-day interdialytic interval (3-day, 22.1 ± 0.6 vs 2-day, 23.0 ± 0.5 mmol/l, p<0.05). The results from this study emphasize the importance of standardization of bicarbonate measurement in order to avoid spurious acidosis.
Renal Clearances in Continuous Ambulatory Peritoneal Dialysis: Differences between Diabetic and Non-Diabetic Subjects
Authors: Tzamaloukas A.H. , Murata G.H. , Malhotra D.
Published: March 2018

We analyzed the effect of diabetes on the decline of residual renal function during the course of CAPD in a cross-sectional study including 105 diabetic subjects (41 women) who had 207 clearance studies and 125 non-diabetic subjects (50 women, 265 clearance studies). CAPD duration was 11.5±10.5 months in the diabetic group (DG) and 16.8±18.6 months in the non-diabetic group (NDG, P < 0.001). The DG had lower urine volume than the NDG (0.52±0.46 vs 0.61±0.50 L/24-h, P < 0.05), while urine-to-plasma concentration ratio was higher in the DG for creatinine (13.5±9.4 vs 11.5±11.0, P <0.05) and did not differ for urea. Weekly renal Kt/V urea (DG 0.51±0.57, NDG 0.53±0.49) and Ccr (DG 31.0±28.7 NDG 29.3±26.5 L/1.73 m2) did not differ. The slopes of the regressions of CAPD duration on renal clearances did not differ. These regressions allowed estimates of the time, from the onset of CAPD, at which renal clearances become negligible. These estimates differed for both urea clearance (DG 35.3, NDG 50.5 months) and creatinine clearance (DG 43.2, NDG 57.6 months). The slope of the regression of renal urea clearance on renal creatinine clearance was steeper in the DG, suggesting a higher renal creatinine clearance in the DG than in the NDG when renal urea clearance is the same in the two groups. Subtle differences in the rate of decline of renal function can be detected between diabetic and non-diabetic subjects on CAPD by detailed statistical analysis. These findings are supportive of the studies which have identified diabetes mellitus as a predictor of loss of residual renal function during the course of CAPD. In addition, the relationship between the renal urea and creatinine clearances differs between diabetic and non-diabetic subjects on CAPD. Therefore, the dose of CAPD required for adequate total clearances may differ between diabetic and non-diabetic subjects.
A comparative prospective study on the use of low concentrate citrate lock versus heparin lock in permanent dialysis catheters
Authors: Hendrickx L. , Kuypers D. , Evenepoel P. , Maes B. , Messiaen T. , Vanrenterghem Y.
Published: March 2018

We prospectively evaluated the efficacy and safety of a low concentrate citrate lock versus heparin lock in permanent single lumen hemodialysis catheters. The frequency of clot formation, complete catheter occlusion, flow problems and the use of urokinase as well as catheter infection episodes were monitored during 1370 dialysis sessions in 19 patients, randomised in two study groups. There was a significantly higher number of dialysis sessions with clot formation in the citrate group but regarding the need for urokinase bolus or infusion, complete obstruction of the catheter or local infections, there were no statistically significant differences between groups. The higher incidence of clotting in the citrate locked catheters had no repercussion on dialysis efficiency, effective blood flow or on the use of thrombolytic therapy. We found that low concentrate citrate is as safe as heparin for long-term interdialytic anticoagulation of permanent single lumen hemodialysis catheters but is more efficient from a pharmaco-economic viewpoint.
Endothelialization of PTFE vascular grafts under flow induces significant cell changes
Authors: Rademacher A. , Paulitschke M. , Meyer R. , Hetzer R.
Published: March 2018

Background

To minimize thrombogeneity of small diameter PTFE grafts they are usually coated in vitro with endothelial cells under static culture conditions. The disadvantage of this technique is that a cell layer is formed that fails to withstand shear stress typical in normal blood flow.

Method

Since the in vivo functional and structural status of endothelial cells correlates with the applied shear stress, we developed a computer-controlled perfusion system to seed and culture cells on PTFE-grafts up to a confluent monolayer under the influence of increasing shear stress. The confluence of endothelial coating was defined by immunohistological staining of cross sections, and by upper light microscopy of flattened graft samples. In addition, the expression of fibronectin as an important adhesion molecule was estimated.

Results and discussion

The application of pulsatile shear stress (6.6 dyn/cm2, 5 min) to grafts endothelialized under perfusion (n = 7) did not lead to a disruption of the confluent cell layer. In contrast, a 5 min long shear stress of 3 dyn/cm2was sufficient to wash more than 50% of cells off the PTFE-graft cultured under static conditions (n = 6). The perfusion cultures showed a significantly higher proliferation rate in comparison with static cultures. This effect was reproducibile in both serum-containing and serum-free culture media. The expression of fibronectin by endothelial cells was significantly higher in the perfused graft compared to the static one. These results suggest the practicability of endothelialized PTFE vascular grafts, preconditioned to shear rates similar to the in vivo situation, as an alternative bypass material in cardiac surgery.
Advanced Glycation end Products: Specific Fluorescence Changes of Pentosidine-Like Compounds during Short Daily Hemodialysis
Authors: Fagugli R.M. , Vanholder R. , De Smet R. , Selvi A. , Antolini F. , Lameire N. , Floridi A. , Buoncristiani U.
Published: March 2018

Background

Advanced glycation end products (AGE) accumulate in uremia and represent an important etiopathogenetic cause of morbidity in dialyzed patients. Conventional hemodialysis treatment seems to be ineffective in lowering AGE levels. We wished to investigate whether daily hemodialysis (DHD), a treatment that seems to result in better clinical condition in end-stage renal disease patients, is effective in the reduction of these compounds.

Methods

We evaluated 10 non-diabetic patients on standard hemodialysis (SHD = 3 × 4h/week) for more than 6 months by a crossover study. These patients were assigned randomly to 6 months of DHD (6 × 2h/week) or 6 months of SHD. Then, they were switched to 6 months of the alternative treatment. At the end of these two periods, we studied pentosidine-like AGE compounds by measuring the total fluorescence at a wavelength characteristic for these substances: Ex: 335nm / Em:385nm; we also measured protein-linked pentosidine at the same time points. Finally, we determined the AGE-related total fluorescence in the deproteinized serum of 13 uremic patients on peritoneal dialysis (CAPD) and of 10 healthy controls.

Results

Pre-HD AGE-related total fluorescence obtained after 6 months of DHD was significantly lower than that obtained with standard HD (DHD = 201.3 ± 36.4 AU/ml vs. SHD = 267.5 ± 141.4 AU/ml, p=0.03). The extraction rate per minute of dialysis was slightly, but not significantly higher during DHD than SHD (0.29 ± 0.11% vs. 0.23 ± 0.04, p = 0.07). AGE-related total fluorescence pre-HD values in patients treated by SHD and DHD were about 20-fold higher than in control subjects. They did not differ from CAPD patients. The pre-dialysis level of protein-linked pentosidine was significantly lower in DHD than in SHD (DHD = 16.12 ± 4.71 pmol/mg protein, SHD = 22.64 ± 6.86 pmol/mg protein, p < 0.01).

Conclusions

DHD showed a reduction in AGE-related total fluorescence, although the mean value remained higher than in control subjects. DHD is also accompanied by a decrease in protein-linked pentosidine.
Influence of ischemic time and temperature on endothelial cell growth after transport
Authors: Dohmen P.M. , Meuris B. , Flameng W. , Konertz W.
Published: March 2018

Background

The preparation of tissue-engineered material is a complex procedure. The possibility to transport tissue between laboratories without loosing endothelial cell (EC) function was examined.

Methods

In 3 month old juvenile sheep (n=6) a piece of vein (n = 14) was harvested and transported over 900 km to the tissue laboratory in Dulbecco's Modified Eagle's Medium (=DMEM). Vein material of each animal was transported at 4°C (Group I, n = 6) and 25°C (Group II, n = 8). EC growth potential was evaluated in function of the medium temperature and the ischemic time (between 8–24 hours). At the end of the first passage the EC of Group I and II were put together to save autologous serum of the sheep. After the 2nd passage the EC were cryopreserved at −80°C to evaluate if EC viability would change.

Results

The growth potential of hypothermic Group I was equal in 16.7% (n = 1), higher in 33.3% (n = 2) and lower in 50% (n = 3) than Group II which had the same ischemic time during transport. Increase in ischemic time up to 24 hours showed no decrease of growth potential. Cryopreservation had no significant influence on EC viability. Viability at the end of the second passage, after recultivation and at the end of the third passage was 97.4% ± 1.52, 95.5%±1.34 and 94.5% ± 1.08 respectively.

Conclusions

In sheep there is no need to transport the EC at a temperature of 4°C. Up to 24 hours growth potential and viability are maintained also at 25°C.
Requirements for an artificial intervertebral disc
Authors: Eijkelkamp M.F. , van Donkelaar C.C. , Veldhuizen A.G. , van Horn J.R. , Huyghe J.M. , Verkerke G.J.
Published: March 2018

Intervertebral disc degeneration is an important social and economic problem. Presently available artificial intervertebral discs (AIDs) are insufficient and the main surgical intervention is still spinal fusion. The objective of the present study is to present a list of requirements for the development of an AID which could replace the human lumbar intervertebral disc and restore its function. The list addresses geometry, stiffness, range of motion, strength, facet joint function, center of rotation, fixation, failsafety and implantation technique. Date are obtained from the literature, quantified where possible and checked for consistency. Existing AIDs are evaluated according to the presented list of requirements. Endplate size is a weak point in existing AIDs. These should be large and fit vertebral bodies to prevent migration. Disc height and wedge angle should be restored, unless this would overstretch ligaments. Finally, stiffness and range of motion in all directions should equal those of the healthy disc, except for the axial rotation to relieve the facet joints.
Mono and Bi-ventricular Assistance: Their Effect on Ventricular Energetics
Authors: Ferrari G. , Górczyńska K. , Mimmo R. , De Lazzari C. , Clemente F. , Tosti G. , Guaragno M.
Published: March 2018

When mono- and bi-ventricular mechanical assistance is used for heart recovery, its control strategy and circulatory variables affect ventricular energetics (external work-EW, oxygen consumption-VO2, cardiac mechanical efficiency-CME). This study is based on the data obtained in vitro and presents an analysis of the effects of the mono- and bi-ventricular mechanical assistance on ventricular energetics. The assistance was conducted on the principle of counterpulsation with atrio-arterial connection. It includes the following stages: 1) the characterisation of the isolated ventricle model in terms of EW, VO2 and CME as a function of the filling pressure and peripheral resistance, 2) modelling of left ventricular and pulmonary dysfunction, followed by left ventricular and bi-ventricular assistance. Experimental data enable us to draw the following conclusions:

• in general, the greatest hemodynamic improvement does not correspond to the highest energetic improvement,

• LVAD assistance deteriorates left ventricular CME while its effect on right ventricular energetics depends on the value of right ventricular elastance (Emax). Right ventricular CME is deteriorated by BVAD assistance irrespective of right Emax,

• the energetics optimisation in bi-ventricular assistance is closely related to the right Emax, which could probably be a deciding factor in the choice of the assistance mode.
Influence of Recombinant Human Erythropoietin Therapy on Plasma Endothelin-1 Levels during Hemodialysis
Authors: Stefanidis I. , Mertens P.R. , Wurth P. , Bach R. , Makropoulos W. , Mann H. , Heintz B.
Published: March 2018

The correction of anemia with human recombinant erythropoietin (rHuEPO) in end stage renal disease is associated with hypertension in about one third of hemodialysis patients. The pathogenesis of the rHuEPO-induced hypertension is still uncertain, though evidence of the involvement of endothelial cells has emerged. The aim of this study was to determine plasma endothelin-1 during hemodialysis and to compare the endothelin-1 levels in hemodialysis patients with and without rHuEPO substitution.

Nineteen stable patients (13 male and 6 female, mean age 62 ± 11 years) with end stage renal disease were studied. Cuprophan dialysers (GFS 12®, Gambro, Lund, Sweden) were used for hemodialysis in all cases. rHuEPO (40U/kg s.c.) was administered to 10 patients. Blood pressure (BP; RR mmHg) and blood volume changes (ΔBV; hemoglobinometry %) were serially measured. Samples were taken before and every hour during hemodialysis. Plasma endothelin-1 was measured by ELISA (R&D Systems, Minneapolis, USA) and corrected for hemoconcentration.

Endothelin-1 concentration was elevated before commencement of hemodialysis (1.16 ± 0.36 pg/ml) when compared to healthy controls (ref. 0.3 - 0.9) and increased to 1.47 ± 0.51 pg/ml by the end of the session (p<0.05). In patients under rHuEPO-substitution plasma endothelin-1 was higher when compared to patients without substitution before (1.25 ± 0.3 vs. 1.05 ± 0.3 pg/ml) and at the end of HD (1.62 ± 0.5 vs. 1.28 ± 0.3 pg/ml, p<0.05). There was no difference in BP and ΔBV between the two groups during treatment.

Plasma endothelin-1 was higher in hemodialysis patients and there was a continuous rise in plasma endothelin-1 during a session. Comparison of two groups of hemodialysis patients with and without s.c. rHuEPO-replacement treatment revealed a significantly higher plasma endothelin-1 concentration in patients with s.c. rHuEPO treatment. However, the elevated endothelin-1 levels were not accompanied by arterial hypertension.
Comparison of Pig, Human and Rat Hepatocytes as a Source of Liver Specific Metabolic Functions in Culture Systems - Implications for Use in Bioartificial Liver Devices
Authors: Vilei M.T. , Granato A. , Ferraresso C. , Neri D. , Carraro P. , Gerunda G. , Muraca M.
Published: March 2018

The limited availability of human hepatocytes results in the use of animal cells in most bioartificial liver support devices. In the present work, clinically relevant liver specific metabolic activities were compared in rat, pig and human hepatocytes cultured on liver-derived biomatrix to optimize the expression of differentiated functions. Pig hepatocytes showed higher rates of diazepam metabolism (2.549±0.821 μg/h/million cells vs. 0.474±0.079 μg/h/million cells rats, p<0.005, and vs. 0.704±0.171 μg/h/million cells in man, p<0.005) and of bilirubin conjugation (21.60116±8.433237 μmoles/l/24 h vs. 6.786809±2.983758 in man, p<0.001 and vs. 9.956538±1.781016 μmoles/l/24 h in rats, p<0.005). Urea synthesis was similar in pig and in human hepatocytes (150±46.3 vs. 144.8±21.46 nmoles/h/million cells) and it was lower in rats (84.38±35.2; p<0.001 vs. man, p<0.02 vs. pig). High liver specific metabolic activities in cultured pig hepatocytes further support their use as a substitue for human cells in bioartificial liver devices
Cuffed-tunneled Femoral Catheter for Long-term Hemodialysis
Authors: Chow K.M. , Szeto C.C. , Leung C.B. , Wong T. Y.H. , Li P.K.T.
Published: March 2018

Background

Hemodialysis access is a challenging problem in patients with exhausted dialysis access sites of their upper extremities. Femoral arterio-venous polytetrafluoroethylene (PTFE) graft is often necessary. The safety and efficacy of cuffed tunneled catheters at the femoral site for long-term hemodialysis has not been extensively studied.

Methods

We inserted 14 cuffed-tunneled femoral catheters in 11 hemodialysis patients with exhausted dialysis access sites of their upper extremities. Access survival and risk of infection were compared with the 11 femoral PTFE grafts in 10 patients of our center during the same period. The choice of dialysis access was determined by the individual nephrologist. Access survival was defined as the achievement of a blood flow rate of at least 180 ml/min.

Results

The median survival of tunneled femoral catheter and PTFE graft were 166 days and 560 days respectively (log-rank test, p = 0.33). Seven of the 14 tunneled femoral catheter remained in use 3 months after insertion. The incidence of catheter- or graft-related infection was 0.38 and 0.23 episodes per 100 catheter / graft days for tunneled femoral catheters and PTFE graft respectively (p = 0.6). Five tunneled catheters and one PTFE graft had to be removed because of infection. Blood flow rates achieved were comparable between tunneled femoral catheter and PTFE graft.

Conclusions

Our preliminary data suggest that the cuffed tunneled femoral catheter has reasonable access survival and an acceptable risk of infection. It may provide a safe and effective access for long-term hemodialysis patients with exhausted access in their upper extremities, especially high risk patients who are not suitable for femoral PTFE graft creation.
A Hybrid (Numerical-physical) Model of the Left Ventricle
Authors: Ferrari G. , Kozarski M. , De Lazzari C. , Clemente F. , Merolli M. , Tosti G. , Guaragno M. , Mimmo R. , Ambrosi D. , Głapinski J.
Published: March 2018

Hydraulic models of the circulation are used to test mechanical devices and for training and research purposes; when compared to numerical models, however, they are not flexible enough and rather expensive. The solution proposed here is to merge the characteristics and the flexibility of numerical models with the functions of physical models. The result is a hybrid model with numerical and physical sections connected by an electro-hydraulic interface - which is to some extent the main problem since the numerical model can be easily changed or modified.

The concept of hybrid model is applied to the representation of ventricular function by a variable elastance numerical model. This prototype is an open loop circuit and the physical section is built out of a reservoir (atrium) and a modified windkessel (arterial tree). The corresponding equations are solved numerically using the variables (atrial and arterial pressures) coming from the physical circuit. Ventricular output flow is the computed variable and is sent to a servo amplifier connected to a DC motor-gear pump system. The gear pump, behaving roughly as a flow source, is the interface to the physical circuit. Results obtained under different hemodynamic conditions demonstrate the behaviour of the ventricular model on the pressure-volume plane and the time course of output flow and arterial pressure.
Design Improvement of the Jellyfish Valve for Long-term Use in Artificial Hearts
Authors: Iwasaki K. , Umezu M. , Imachi K. , Iijima K. , Fujimoto T.
Published: March 2018

In a previous communication, we reported a leaflet fracture in a Jellyfish valve that was incorporated into a blood pump, after a 312-day animal implant duration. Subsequent finite element analysis revealed that the fracture location was consistent with an area of maximum strain concentration. Therefore, the aim of this study was to improve the durability in the light of these findings. Based on the engineering analysis results, a new valve seat having a concentric ring of 0.5mm width, located at a radius of 7.0 mm, was designed and fabricated. Accelerated fatigue tests, conducted under the conditions recommended by ISO 5840, demonstrated that the durability of this new prototype was extended by a factor of 10, as compared to the original valve. Moreover, further finite element analysis indicated that the maximum equivalent elastic strain of the proposed new valve was reduced by 52.3% as compared to the original valve. Accordingly, it has been confirmed that the modified Jellyfish valve is suitable for use in long-term artificial hearts.
Effect of Low Molecular Weight Heparin on Bone Metabolism and Hyperlipidemia in Patients on Maintenance Hemodialysis
Authors: Lai K.N. , Ho K. , Cheung R.C.K. , Lit L.C.W. , Lee S.K.M. , Fung K.S. , Tong M.K.L. , Lam C.W.K.
Published: March 2018

The effect of low molecular weight heparin (LMWH) on serum lipid profile in hemodialysis remains controversial and its effect on bone metabolism has not been studied. A crossover study was conducted in 40 patients on stable hemodialysis using unfractionated heparin (UFH) for more than 24 months. These patients were then treated with a LMWH (nadroparin-Ca) for 8 months during hemodialysis and subsequently switched back to UFH for 12 months. Serum lipid profile, biochemical markers for bone metabolism, and bone densitometry (BMD) were monitored at four-month intervals while all medications remained unchanged.

Cholesterol (TC), triglyceride (TG), low-density lipoprotein-cholesterol (LDL-C), lipoprotein(a) (Lp(a)), apolipoprotein B (Apo B) were raised in 35%, 29%, 12%, 24% and 24% of patients respectively. High-density lipoprotein-cholesterol (HDL-C) and apolipoprotein A1 (Apo A-1) were reduced in 47% and 9% of patients. Bone-specific alkaline phosphatase (BALP) and intact osteocalcin (OSC), both reflecting osteoblastic activity, were raised in 65% and 94% of patients. Tartrate-resistant acid phosphatase (TRACP) reflecting osteoclastic activity and parathyroid hormone (PTH) were elevated in 35% and 88% of patients. Following LMWH treatment, TC, Tg, Lp(a) and Apo B were reduced by 7%, 30%, 21% and 10% respectively (p<0.05 or <0.01) while Apo A-1 were raised by 7% (p<0.01). Simultaneously, TRACP was reduced by 13% (p<0.05). These biochemical changes were detected soon after 4 months of LMWH administration. Although BMD values in our patients were lower than those of age-matched normal subjects, significant changes were not observed with LMWH treatment. After switching back to UFH for hemodialysis, these biochemical indices reverted to previous values during UFH treatment with a significant higher level in TC and Apo B while serum Apo A-1 remained elevated. Our study suggests LMWH may partially alleviate hyperlipidemia and, perhaps, osteoporosis associated with UFH administration in patients on maintenance hemodialysis.
Heparin Coating of the Extracorporeal Circuit Combined with Leukocyte Filtration Reduces Coagulation Activity, Blood Loss and Blood Product Substitution
Authors: Martens S. , Matheis G. , Wimmer-Greinecker G. , Feuerbach J. , Jakob A. , Mierdl S. , Moritz A.
Published: March 2018

Background

Cardiopulmonary bypass is associated with activation of the coagulation cascade. Occasionally, this results in postoperative hemorrhage and consequently the need for blood products associated with increasing costs and risk of infection. Contact activation of the intrinsic coagulation pathway, and damage to cellular blood components with the release of proteolytic substances from neutrophil granulocytes have been linked to these coagulation disorders.

Methods

Eighteen routine CABG-patients were randomly assigned to totally heparin coated circuits (Bioline coating) combined with leukocyte filtration in a double blind protocol (group I), 34 patients served as controls (group II). Leukocyte filters were activated before release of the aortic crossclamp. Coagulation activity, postoperative blood loss, and substitution with blood products were assessed.

Results

Blood loss in the first 24h after surgery was significantly lower with combined application of heparin coating and leukocyte filters (group I) vs. controls (group II) (526±78ml vs. 786±88ml; p<0.05). Thrombin formation represented by prothrombin fragments 1+2 was significantly lower in group I vs. group II after declamping of the aorta (2.1±0.3nmol/L vs. 4.0±0.3nmol/L; p<0.05). Group I showed higher AT III plasma than group II (48.8±3.2% vs. 41.5±1.7%; p<0.05).

Conclusions

Leukocyte filtration during reperfusion in heparin coated cardiopulmonary bypass circuits is associated with lower coagulation activation, decreased blood loss and reduced transfusion of packed red cells in elective CABG patients.
Hydrodynamic Characterisation of Ventricular Assist Devices
Authors: Vandenberghe S. , Segers P. , Meyns B. , Verdonck P.
Published: March 2018

A new mock circulatory system (MCS) was designed to evaluate and characterise the hydraulic performance of ventricular assist devices (VADs). The MCS consists of a preload section and a multipurpose afterload section, with an adjustable compliance chamber (C) and peripheral resistor (Rp) as principal components. The MCS was connected to a pulse duplicator system for validation, simulating a wide range of afterload conditions. Both pressure and flow were measured, and the values of the different components calculated. The data perfectly fits a 4-element electrical analogon (EA). The MCS was further used to assess the hydrodynamic characteristics of the Medos VAD as an example of a displacement pump. Data was measured for various MCS settings and at different pump rates, yielding device specific pump function graphs for water and pig blood. Our data demonstrate (i) flow sensitivity to preload and afterload and (ii) the effect of test fluid on hemodynamic performance.