bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Transmyocardial Laser Revascularization (TMLR) on Regional Cardiac Function and Metabolism in an Isolated Hemoperfused Working Pig Heart
Authors: Modersohn D. , Eddicks S. , Ast I. , Holinski S. , Konertz W.
Published: January 2018

The mechanism of an indirect revascularization in ischemic myocardium by transmyocardial laser revascularization (TMLR) is not yet fully understood. An improvement of clinical symptoms caused by TMLR is reported in many clinical trials with patients in which a direct revascularization is not possible. An increase of myocardial perfusion through laser channels is doubtful, because the myocardial pressure in the wall is higher than in the cavum. Therefore we measured the local cardiac function (intramyocardial pressure, wall thickness, pressure-length curves) and acute metabolic changes (tissue lactate content, tissue pO2) in ischemic and non-ischemic regions before and after TMLR in isolated hemoperfused pig hearts. An isolated heart was chosen because it enabled us to separate coronary flow from flow through ventricular channels. The ischemia was induced by coronary occlusion or microembolization (eight hearts each). It should be noted that microembolization leads to conditions which are more comparable with those found in patients selected for TMLR. In the isolated working heart, the coronary perfusion can be controlled independently from perfusion through the ventricular cavum. Under the ischemic conditions mentioned above, we observed that the intramyocardial pressure in the ischemic region decreased below the left ventricular pressure, so one premise for indirect perfusion was met. TMLR after microembolization led to a significant improvement of regional cardiac work and the tissue oxygen pressure. These acute effects demonstrate the possibility of functional and metabolic amelioration by TMLR after ischemia induced by microembolization in an isolated hemoperfused pig heart.
Regenerative Repair of the Mandible using a Collagen Sponge Containing TGF-ß1
Authors: Shigeno K. , Nakamura T. , Inoue M. , Ueda H. , Kobayashi E. , Nakahara T. , Lynn A.K. , Toba T. , Yoshitani M. , Fukuda S. , Kawanami R. , Shimizu Y.
Published: January 2018

Introduction:

Alveolar bone resorption and atrophy of the mandible are a major challenge for regeneration medicine. In the present investigation, a collagen sponge that contained TGF-ß1 was placed at a mandibular defect and the osteogenic effects of collagen-TGF-ß1 complex were evaluated.

Material and Methods:

The Pm2, Pm3, and Pm4 teeth on both sides of the mandibles of 12 adult beagle dogs (9.0–12.0 kg) were extracted. After the extraction-site wounds healed, a bone defect (10.0 × 15.0 mm-wide, 10.0mm-deep or 10.0 × 10.0mm-wide,10.0mm-deep) was created on the mandible. A collagen sponge (10.0 × 10.0 × 10.0 mm) that contained TGF-ß1 (1.0 μg, 5.0 μg, or 10.0 μg, in physiological saline) was placed at the bottom of the defect and the overlying mucous membrane was sutured with 4–0 prolene. As a control, a collagen sponge that contained physiological saline only was placed in a defect on the opposite side. Two weeks after the surgery the wounds above the bone defects on both the control and TGF-ß1-treated sides had healed completely.

Results:

At four, six, or eight weeks post-operatively animals were killed. Soft X-ray and bone-salt measurement analyses confirmed clearly that there was greater calcified bone formation in the defects into which TGF-ß1 had been incorporated than with the control defects. The implanted collagen sponges were fully resorbed and the bone tissue had regenerated from the bottom of the defects on the TGF-ß1 side by four weeks. On the control side, no such regeneration was observed.

Conclusions:

These results indicate that TGF-ß1 released slowly from a collagen sponge was effective in promoting bone remodeling when applied to mandibular defects in adult dogs.
Mechanical Resistance of Biological Repair Cartilage: Comparative in vivo Tests of Different Surgical Repair Procedures
Authors: Gerber B.E. , Robinson D. , Nevo Z. , Brosh T. , Ash H. , Yayon A. , Aviezer D.
Published: January 2018

The former common knowledge that cartilage lesions do not heal has been modified over the last few years due to new technologies. For repair of deeper circumscribed lesions osteochondral press-fit grafting and tissue engineering are used in clinical application.

The histological data of the hyaline-like tissue obtained by engineering are just as satisfactory as the surviving grafted hyaline cartilage on top of osteochondral cylinders. But comparative studies are still lacking. To fill the gap and with a view to repairing larger osteoarthritic defects we have performed an in vivo study on 16 goats.

Three months after the creation of a full thickness wide cartilage defect on the femoral condyle with harvesting of cartilage samples for tissue cultures we performed secondary cartilage repair procedures on the installed osteoarthritis areas: 1) grafting with autogenic osteochondral press-fit cylinders from the opposite knee, 2) autologous engineered chondrocyte grafting under periosteal flaps, 3) both in combination. The harvesting defects were either left as controls or filled with a hyaluronate fleece. After eight months the repaired areas and the harvesting defects were examined for cartilage stiffness as a novel comparative parameter.

Compared to normal the cartilage on top of osteochondral grafts is considerably stiffer. Engineered cartilage is weaker than normal. Spontaneously ingrown fibrous cartilage is much weaker even with a carrier fleece. A combination of osteochondral press-fit grafts with engineered autologous cells restores biomechanical qualities to repaired larger degenerative cartilage defects.
Platelet Activation and PDGF-AB Release during Dialysis
Authors: Donati G. , Cianciolo G. , D'addio F. , Colì L. , La Manna G. , Feliciangeli G. , Stefoni S.
Published: January 2018

During hemodialysis the blood-membrane contact causes a release of platelet granule content, which contains Platelet Derived Growth Factor (PDGF-AB). In view of its possible role in accelerated atherosclerotic processes, we evaluated the intra- and post-dialytic changes in PDGF-AB serum levels during hemodialysis sessions performed with Hemophan and Polysulfone membranes.

PDGF-AB, PF4, ßTG and MPV levels were determined in the peripheral blood in 30 patients each of whom underwent 6 dialysis sessions: 3 with Hemophan (HE) membrane and 3 with Polysulfone (PS) membrane, interpolated by a wash out session with PS membrane. Blood samples were taken at times 0’, 30’, 120’, 180’, 240’ during dialysis sessions and at 1, 4 and 20 hours after the end of the session. Statistical analysis was done using the ANOVA one way test and Student's t test. PDGF-AB serum levels initially increased and, except for a sharp fall at 120’, remained constantly high during HD with both membranes tested, not returning to basal values until 20 hours after the end of the session. PF4, ßTG and MPV all showed a similar trend to PDGF. No statistically significant difference was found between the two membranes tested.

PDGF-AB, a powerful growth factor in cells of mesenchymal origin, is released during dialysis mainly as a result of the blood-membrane contact. This we found regardless of the type of dialyzer we tested, and, above all, proved to return very slowly to basal values. We speculate that the release of PDGF-AB could play a part like other atherosclerosis risk-factors in the appearance and worsening of atherosclerotic lesions in hemodialysis patients.
Heart Rate Effect on Hemodynamics during Mechanical Assistance by the Intra-Aortic Balloon Pump
Authors: Papaioannou T.G. , Terrovitis J. , Kanakakis J. , Stamatelopoulos K.S. , Protogerou A.D. , Lekakis J.P. , Nanas J.N. , Stamatelopoulos S.F.
Published: January 2018

Heart rate (HR) has been characterized as an important cardiovascular parameter that affects acute hemodynamic performance of intra-aortic balloon counterpulsation (IABC). However, the effect of HR on hemodynamics during mechanical assistance by the IABC has neither been clarified nor quantified. We sought to evaluate the relationship between IABC and HR and also to examine whether there is a range of HR with optimum hemodynamic response to IABC.

Methods.

20 patients (14 males - 6 females, mean age 64.4±11.4 years) with post-infarction cardiogenic shock undergoing IABC treatment were evaluated. Hemodynamics were recorded for each patient once per day during the assistance period; 131 measurements were taken and thus a wide range of heart rates was obtained (64–141 bpm). The following changes in aortic pressures were used to evaluate acute IABC performance on: a) the maximal increase of diastolic aortic pressure induced by IABC and b) the reduction in systolic and end-diastolic aortic pressure.

Results.

Non-linear regression analysis and analysis of variance revealed that a significant correlation exists between IABC performance indices and heart rate. At HR<80 bpm, IABC performance tended to be reduced, whereas the increase in HR above 110 bpm resulted in a significant reduction of all IABC performance indices. In contrast, IABC operating at 80–110 bpm resulted in optimum hemodynamic performance. In conclusion, the effect of heart rate on IABC performance is non-linear indicating that IABC may be more effective when operating within 80–110 bpm.
Impact of Continuous Veno-venous Hemofiltration on Acid-base Balance
Authors: Rocktäschel J. , Morimatsu H. , Uchino S. , Ronco C. , Bellomo R.
Published: January 2018

Background

Continuous veno-venous hemofiltration (CVVH) appears to have a significant and variable impact on acid-base balance. However, the pathogenesis of these acid-base effects remains poorly understood. The aim of this study was to understand the nature of acid-base changes in critically ill patients with acute renal failure during continuous veno-venous hemofiltration by applying quantitative methods of biophysical analysis (Stewart-Figge methodology).

Methods

We studied forty patients with ARF receiving CVVH in the intensive care unit. We retrieved the biochemical data from computerized records and conducted quantitative biophysical analysis. We measured serum Na+, K+, Mg2+, Cl-, HCO3-, phosphate, ionized Ca2+, albumin, lactate and arterial blood gases and calculated the following Stewart-Figge variables: Strong Ion Difference apparent (SIDa), Strong Ion Difference Effective (SIDe) and Strong Ion Gap (SIG).

Results

Before treatment, patients had mild acidemia (pH: 7.31) secondary to metabolic acidosis (bicarbonate: 19.8 mmol/L and base excess: −5.9 mEq/L). This acidosis was due to increased unmeasured anions (SIG: 12.3 mEq/L), hyperphosphatemia (1.86 mmol/L) and hyperlactatemia (2.08 mmol/L). It was attenuated by the alkalinizing effect of hypoalbuminemia (22.5 g/L). After commencing CVVH, the acidemia was corrected within 24 hours (pH 7.31 vs 7.41, p <0.0001). This correction was associated with a decreased strong ion gap (SIG) (12.3 vs. 8.8 mEq/L, p <0.0001), phosphate concentration (1.86 vs. 1.49 mmol/L, p <0.0001) and serum chloride concentration (102 vs. 98.5 mmol/L, p <0.0001). After 3 days of CVVH, however, patients developed alkalemia (pH: 7.46) secondary to metabolic alkalosis (bicarbonate: 29.8 mmol/L, base excess: 6.7 mEq/L). This alkalemia appeared secondary to a further decrease in SIG to 6.7 mEq/L (p <0.0001) and a further decrease in serum phosphate to 0.77 mmol/L (p <0.0001) in the setting of persistent hypoalbuminemia (21.0 g/L; p=0.56).

Conclusions

CVVH corrects metabolic acidosis in acute renal failure patients through its effect on unmeasured anions, phosphate and chloride. Such correction coupled with the effect of hypoalbuminemia, results in the development of a metabolic alkalosis after 72 hours of treatment.
Inflammatory Response of a New Synthetic Dialyzer Membrane. a Randomised Cross-over Comparison between Polysulfone and Helixone
Authors: Stefoni S. , Colì L. , Cianciolo G. , Donati G. , Ruggeri G. , Ramazzotti E. , Pohlmeier R. , Lang D.
Published: January 2018

Hemodialysis patients suffer from chronic inflammation due to intradialytic contact of blood with artificial materials. The FX 60 dialyzer which belongs to the new FX-class series of dialyzers is composed of the new membrane Helixone®. This membrane is derived from the original Fresenius Polysulfone® membrane. The FX-class design is based on modified geometry of fibres and housing and has resulted in a new dialyzer with improved efficiency, safety and ease of handling compared to the F series (F 60S) dialyzer.

The aim of the study was to investigate whether the biocompatibility pattern in terms of inflammatory parameters of the new type of polysulfone dialyzer has changed compared to the standard. A clinical in vivo study was conducted to compare the intradialytic inflammatory response of the two dialyzers, FX 60 and F 60S. Eight chronic dialysis patients were selected for the study: mean age 65.5±15.5 years, mean time on dialysis 100±95 months. The randomized cross-over study involved a treatment period of 2 weeks (total 6 sessions), one week with each dialyzer, starting with one or the other according to the randomization scheme. Blood samples were taken at 0 (T0), 15, 60, and 240 minutes to evaluate white blood cell (WBC) count, complement factor C5a, leukocyte elastase, soluble intercellular adhesion molecule 1 (sICAM-1), platelet count, C-reactive protein (CRP).

At 15 min, WBC count showed a comparably, low decrease for both dialyzers: −7.6 % for FX 60 versus −6.6 % for F 60S, p=not significant (ns). At the same time the C5a concentration decreased from 15.0±7.5 ng/ml to 13.5±6.7 ng/ml (p=ns) for FX 60, and from 15.1±12.5 ng/ml to 14.9±25.0 ng/ml for F 60S (p=ns). The elastase concentration progressively increased over time with no statistical difference between the two dialyzers. The levels of sICAM-1, CRP, and platelet count were similar at each time point for both dialyzers, varying around the baseline values (p=ns).

No significant difference emerged in terms of inflammatory response between the two dialyzers, demonstrating that the biocompatibility of the F-series was maintained in the FX-class series of dialyzers and is independent of design factors.
Successful ex Vivo Normothermic Liver Perfusion with Purely Artificial Products using Artificial Blood
Authors: Nui A. , Katsuramaki T. , Kikuchi H. , Kukita K. , Nagayama M. , Meguro M. , Kimura H. , Isobe M. , Hirata K.
Published: January 2018

We tried to make an ex vivo functioning liver with an artificial perfusate that consisted of artificial blood in the pig liver. A liver graft from a female pig weighing 20 kg was harvested in the usual manner. The perfusion solution consisted of artificial blood, L-15 medium, distilled water, bovine serum albumin, NaHCO3, NaOH, KCl, human regular insulin, 50% glucose solution, and dexamethasone. The isolated liver was perfused with this oxygenated perfusate through the portal vein at a rate of 300 ml/min for 9 hours. Seven livers were perfused for 9 hours in this system. Five of the livers showed mean oxygen consumption of over 8 ml-02/min during perfusion. Histological findings showed that the hepatic architecture was almost completely preserved and numerous hepatocytes exhibited PAS-positive cytoplasmic glycogen deposits in these livers.

These observations indicate that we have succeeded in developing an ex vivo functioning liver with an artificial perfusate employing artificial blood.
Pathological Patient in Protocol Definition for Bench Testing of Mechanical Cardiac Support System
Authors: Grigioni M. , Daniele C. , Romanelli C. , Morbiducci U. , D'Avenio G. , Del Gaudio C. , Barbaro V.
Published: January 2018

Clinical techniques for the restoration of a failing heart are mainly based on the use of mechanical assist devices. In recent years, with the growing need for mechanical circulatory support, these devices have been shown to be a useful therapeutic tool, thanks to their intrinsic capability to unload the failing ventricle, allowing the heart to recover. Mechanical circulatory support systems (MCSS) require an accurate biomechanical characterization of the complex interaction that occurs between the patient and the mechanical support. A protocol for MCSS testing is proposed which takes into account several working conditions, in a modified test mock loop apparatus able to mimic various pathological conditions. Both physiological and pathological conditions can be replicated to show the actual efficacy of a MCSS device in correctly supporting a wide spectrum of ventricular conditions. The test bench is able to simulate the recovery of the pathological condition quite accurately, showing, at the same time, that this set up can be a reliable choice to characterize cardiac support devices. Thus the results of this experimentation can be useful to clinicians in forecasting the response of the heart affected by a cardiac disease and to set appropriate parameters for suitable assistance.
Impact of Blood and Dialysate Flow and Surface on Performance of New Polysulfone Hemodialysis Dialyzers
Authors: Mandolfo S. , Malberti F. , Imbasciati E. , Cogliati P. , Gauly A.
Published: January 2018

Optimization of hemodialysis treatment parameters and the characteristics of the dialyzer are crucial for short- and long-term outcome of end stage renal disease patients. The new high-flux membrane Helixone® in the dialyzer of the FX series (Fresenius Medical Care, Germany) has interesting features, such as the relationship of membrane thickness and capillary diameter which increases middle molecule elimination by convection, as well as higher capillary packing and microondulation to improve the dialysate flow and distribution.

Blood flow, dialysate flow and surface area are the main determinants of the performance of a dialyzer, however the impact of each parameter on small and middle molecule clearance in high flux dialysis has not been well explored. In order to find the best treatment condition for the new dialyzer series, we evaluated urea, creatinine, phosphate clearances and reduction rate of ß2-microglobulin in ten stable patients treated with different blood flows (effective Qb 280 and 360 ml/min), dialysate flow (Qd 300 or 500 ml/min) and dialyzer surfaces (1.4 and 2.2 m2, FX60 or FX100). KoA and Kt/V were also calculated.

Blood flow, dialysate flow and surface area demonstrated a significant and independent effect on clearance of urea, creatinine and phosphate, as well as on Kt/V. Small solute clearance was stable over the treatment. In contrast to small solutes, reduction rate of ß2-microglobulin was related to increasing dialyzer surface only.

The new dialyzer design of the FX series proves highly effective due to improved dialysate distribution and reduced diffusive resistance as shown by the small solute clearance. A high reduction rate of ß2-microglobulin is favored by improved fiber geometry and pore size distribution. These findings have potential long-term benefits for the patient
Peritoneal Leukocyte Survival and Respiratory Burst Responses in Patients Treated with a Low Glucose Degradation and High pH Peritoneal Dialysis Fluid
Authors: Jonasson P. , Albrektsson A. , Ljungman S. , Wieslander A. , Braide M.
Published: January 2018

The discovery of toxicity related to glucose degradation products (GDP) has initiated the development of new PD fluids with low GDP concentrations and higher, more physiological, pH levels.

Cell numbers, differential counts and the respiratory burst responses of peritoneal leukocytes were compared between patients treated with the low GDP, high pH fluid Gambrosol-trio® (n=10) and a conventional fluid (n=12). Effluents from over-night dwells were collected and leukocytes were evaluated morphologically and by luminol-amplified chemiluminescence (CL) after stimulation with opsonized zymosan. The frequency of necrosis and early apoptosis was quantified by means of annexin V binding and propidium iodide uptake. The Gambrosol-trio® group produced significantly higher (p<5%) macrophage counts and stronger CL responses (p<10%) than did the conventional fluid group. The cell compositions did not differ significantly between the groups. Necrosis was significantly more common among the cells in the conventional fluid group. The occurrence of apoptosis did not differ between the fluids.
Relationship between Diabetes Mellitus and Degree of Coronary Artery Disease in Uraemic Patients Investigated with Coronary Angiography
Authors: Fabbian F. , Benussi P. , Cacici G. , Cavallini L. , Loschiavo C. , Ortalda V. , Todini V. , Maschio G.
Published: January 2018

Prevalence of cardiovascular disease is high in diabetic patients on renal replacement therapy (RRT); therefore we examined the role of diabetes mellitus on determining the degree of coronary artery stenosis. Twenty-five patients underwent coronary angiography, 12 were awaiting kidney transplantation and the examination was performed regardless of cardiac symptoms, 13 were affected by ischaemic heart disease (IHD). Diabetic and nondiabetic status together with the other risk factors for cardiovascular disease such as age, sex, length of time on RRT, smoking and elevated phosphorus levels history, clinical diagnosis of IHD, cerebrovascular and peripheral vascular disease, mean blood pressure, cholesterol, triglycerides, calcium, phosphate, albumin, haemoglobin, haematocrit and weekly dose of erythropoietin were derived from clinical records. All investigated parameters were matched in diabetic (group 1, n=10) and nondiabetic patients (group 2, n=15) and showed no differences. Clinical evidence of IHD was detected in 80% of patients in group 1 and 46% in group 2 and the percentage of patients on the renal transplant waiting list was not statistically different in the two groups (30 vs 60%). In 60% of patients in group 1 there were 3 or more stenotic lesions equal or greater than 75% of normal reference segment in the major coronary arteries, whilst in 53% in group 2 there were no haemodynamically significant narrowings. Narrowing percentage of the coronaries in group 1 and 2 were: right coronary artery 83±30 vs 32±41 (p <0.05), left anterior descending artery 80±25 vs 44±34 (p <0.05), left circumflex artery 46±37 vs 18±29 (p=0.05) respectively. Our study confirms that IHD is a clinical feature of uraemic diabetic patients and that diabetes is the main cardiovascular risk factor for determining the degree of coronary stenosis.
Demand Dynamic Bio-girdling in Heart Failure: Improved Efficacy of Dynamic Cardiomyoplasty by LD Contraction during Aortic Out-flow
Authors: Carraro U. , Rigatelli G. , Rossini K. , Barbiero M. , Rigatelli G.
Published: January 2018

Purpose

The value of dynamic cardiomyoplasty has been brought into question by the disappointing results produced by slow contraction-relaxation cycle and possibly degeneration of the latissimus dorsi muscle (LD) secondary to temporary tenotomy and chronic daily electrical stimulation. Objective of our study is to determine whether daily periods of rest introduced by demand stimulation in the continuous contraction protocol produce systolic assistance and improve clinical results.

Methods

Twelve dynamic cardiomyoplasty patients (mean age 58.2±5.8 years, M/F=11/1, sinus rhythm/atrial fibrillation=11/1) with dilated myocardiopathy were enrolled in an unrandomized trial of Demand Dynamic Heart Bio-Girdling in a public regional teaching hospital. Periods of LD inactivity, each lasting several hours, were introduced daily on a heart rate-based demand regime. To avoid full transformation of LD, fewer impulses per day were delivered, daily providing the LD with long periods of rest (Demand light stimulation). The contractile properties were measured by transcutaneous non-invasive LD tensiomyogram interrogation (LD tensiomyogram). Bio-Girdle activation was synchronized to heart beat by combining tensiomyogram and echocardiography. Clinical, echocardiographic and hemodynamic records, as well as aortic flow measurements by Doppler aortic flow wire were taken during the follow-up.

Main findings

Mean duration of the demand stimulation follow-up was 40.2+13.8 months. At five years, “Demand stimulation” shows: 1) no operative death; 2) 83% actuarial survival; 3) highly significant 47.4% decrease of the NYHA class (from 3.17±0.38 to 1.67±0.77, p=0.0001); 4) 41.6% improvement of LVEF (from 22.6±4.38 to 32.0±7.0, p=0.001); 5) 7.5±3.0% increase in aortic flow velocity peak in assisted vs. unassisted beats, and 6) preservation of LD from slowness (TFF value 33±7.86 at follow-up versus 15.8±11.1 Hz just before switching from continuous to demand stimulation, p=0.0001) and muscle degenerative atrophy.

Conclusions

In dynamic cardiomyoplasty the demand light stimulation maintains LD contraction properties over time, produces effective systolic assistance, and improves clinical results. Demand dynamic bio-girdling is a safe and effective treatment for end-stage heart failure in selected patients.
Effectiveness of Long-term Heparin-induced Extracorporeal LDL Precipitation (HELP) in Improving Coronary Calcifications
Authors: Ramunni A. , Morrone L.F. , Baldassarre G. , Montagna E. , Saracino A. , Coratelli P.
Published: January 2018

There is clear clinical evidence that a drastic lowering of plasma LDL- Cholesterol (LDL) concentrations significantly reduces the rate of total and coronary mortality as well as the incidence of cardiovascular events in high risk hypercholesterolemic patients. We describe the case of a 51-year-old woman with coronary heart disease (CHD) who presented with increasing angina on exertion in 1995, at the age of 45. She suffered from a heterozygous familial hypercholesterolemia and in 1985 her total cholesterol (TCHO) was 328±62 mg/dl (mean value of ten analysis). After ten years of statins her mean values (20 analysis, 2 per year) were: TCHO 259±71, LDL 209±47, HDL 35±7 mg/dl. Coronary angiography (CA) performed in 1995 disclosed three vessel coronary heart disease with significant stenoses of the distal right coronary artery, multiple calcifications of the interventricularis artery and multiple plaques with significant stenoses in the ramus circumflexus. The woman underwent coronary by-pass surgery. Thereafter the patient was treated for six years with HELP in biweekly intervals, in combination with statins. TCHO, LDL, HDL and fibrinogen (fb) levels were measured before and after each treatment. Their mean values for an amount of 120 sessions were: TCHO pre 216±23, post 111±18 LDL pre 152±16 post 67±18, HDL pre 42±5 post 35±4 fb pre 306±48 post 125±31. In 2001 a new CA was performed. Calcifications disappeared and stenoses were identical to the previous CA or reduced. There were no further clinical manifestations of CHD. We trust that the clinical benefit of the HELP procedure will be substantial for those patients who have problems in clearing LDL from their plasma pool and who are at the same time sensitive to elevated LDL levels by the development of premature coronary sclerosis.
System Design of a Bioartificial Liver with a High Performance Hemodialyzer as an Immunoisolator Using a Mathematical Kinetic Model
Authors: Kanamori T. , Yanagi K. , Sato T. , Shinbo T. , Ohshima N.
Published: January 2018

We propose a new bioartificial liver (BAL) system equipped with a high performance hemodialyzer to act as an immunoisolation device. We discuss the design of the BAL system using a mathematical kinetic model with the experimentally obtained mass-transfer performances of various hemodialyzers. The mass transfer resistances of the hemodialyzers did not adversely influence the ammonia-removal and bioactive-substance-supply performances of the BAL system. A suitable hemodialyzer for the BAL system is available even at present using an engineering design. The remaining problems to be overcome before realizing clinical use of the BAL system are to increase the rate constant of the first order reaction of the BAL for ammonia metabolism and to develop a new method of blood access that can be used safely with long term reliability at a high blood flow rate (ca. 556 ml/min).
Is There a Survival Advantage in Asian Peritoneal Dialysis Patients?
Authors: Li Philip K.-T. , Chow K.M. , Szeto C.C.
Published: January 2018

Over the last decade, epidemiological surveys and qualitative research literature have demonstrated and validated a better survival in the Asian peritoneal dialysis population. This review summarizes the current understanding of Asian peritoneal dialysis patient survival and attempts to scrutinize the supposed survival advantage of this population group. We outlined the published peritoneal dialysis survival data from a literature search, with reference to dialysis patient cohorts from 1983 through 2002 for prevalent cases and 1980 through 2002 for incident patients. Two-year and 5-year patient survival rates in excess of 80% and 60% respectively were demonstrated in Asian countries, which compared favorably with the CANUSA, ADEMEX and most Caucasian series. Better end-stage renal disease patient survival is apparent despite a dialysis adequacy disadvantage, for reasons yet to be identified. As is the case of other racial disparities in medical care, such a difference is a product of more than biological differences and include budgetary barrier, health care system and geographic variation, physician bias and statistical pitfalls. Particular efforts should therefore be made to explore the underlying reason(s) for the Asian peritoneal dialysis patient survival advantage. Alternative approach and guidelines to peritoneal dialysis delivery in Asia might be warranted.
AnyHeart: A Single-piece Heart-saving Implantable Artificial Heart (BVAD) - Monitoring and Estimation
Authors: Park J.W. , Choi J. , Lee J.J. , Nam K. , Chung J. , Park S.K. , Park C.Y. , Sun K. , Kim W.G. , Kim J. , Min B.G.
Published: January 2018

AnyHeart is a single-piece, implantable biventricular assist device. This electromechanical BVAD has a moving-actuator mechanism.

To monitor the status of AnyHeart from anywhere at any time, a portable personal digital assistant (PDA) monitor and web-based remote monitoring system were developed. The PDA local monitoring system has replaced bulky personal computer monitoring systems. The web-based remote monitoring system has several functions such as data collecting, storing, and posting through the internet.

Basically, interventricular pressure (IVP) is a parameter indicating the filling level of the blood chambers of AnyHeart. The pump output can be estimated using IVP, which is acquired noninvasively from AnyHeart. With the proposed method, we can estimate the pump output with a small margin of error.
Applications of the Pulsatile Flow Versatile ECLS: In Vivo Studies
Authors: Rho Y. R. , Choi H. , Lee J.C. , Choi S.W. , Chung Y.M. , Lee H.S. , Hwang C.M. , Lee H.S. , Ahn S.S. , Lee R.Y. , Son H.S. , Choi M.J. , Baek K.J. , Kim J.S. , Suh G.J. , Won Y.S. , Sun K. , Min B.G.
Published: January 2018

Introduction

T-PLS (Twin-Pulse Life Support) is the first commercial pulsatile ECLS (Extra Corporeal Life Support) device (1). The dual sac structure of T-PLS can effectively reduce high membrane oxygenator inlet pressure and hemolysis. To verify both the use of T-PLS for ECLS and the advantages of T-PLS, we tested various models.

Method and Results

In the partial CPB (cardio pulmonary bypass) model (swine), T-PLS (N=6), and Biopump (N=2), a single pulsatile pump (N=2), were compared. In the case of single pulsatile flow, during pump systole, pressure increased to 700 - 800 mmHg at the inlet port of the membrane oxygenator. fHb, a hemolysis measurement value, was about 80 mg / dL at 3 hours. On the contrary, because of T-PLS's dual sac system, the pressure of T-PLS had a maximum value of about 250 mmHg and fHb was similar to that of the commercial centrifugal pumps. In the total CPB model (bovine, N=6), the heart was stopped via cardioplegia (Kcl). T-PLS flow was maintained at 3.0 - 4.5 L/min. T-PLS functioned like a natural heart, having a pulse pressure of 26 - 43 mmHg and a pulse rate of 40 - 60 bpm (beats per minute). In the emergency case model (canine, N=6), T-PLS was started 10 minutes after cardiac arrest from electronic shock. In spite of cardiac arrest for a period of 40 minutes, the heart was recovered after defibrillation. In the ARDS (Acute Respiratory Distress Syndrome) model (canine, N=6), minimal ventilator parameters were set: tidal volume 130 ml, respiration rate = bpm, FiO2 = 10%. Three hours after starting T-PLS, PO2 of the carotid artery blood (after 2 hours: 195 ±89.4; after 3 hours: 258 ±99.3 mmHg) was above half the value of the femoral artery but was within normal range.

Conclusion

It is suggested that a portable pulsatile ECLS like T-PLS may be used as a CPB device and as an alternative CPR (cardiopulmonary resuscitation) device in the case of cardiac arrest. Due to the pulsatile flow, oxygenated blood is delivered to the patient without overloading the ARDS patient's heart.
Diacap® α-Polysulfone HI PS: a New Dialysis Membrane with Optimum β2-Microglobulin Elimination
Authors: Mann H. , Al-Bashir A. , Melzer H. , Stiller S.
Published: January 2018

Background

Plasma concentration of β2-microglobulin (β2-m) in the case of renal insufficiency is about 20 to 30 times higher than normal. β2-m is associated with secondary amyloidosis, a late complication of regular dialysis therapy. To prevent the complications of secondary amyloidosis β2-m should therefore be eliminated as efficiently as possible during dialysis treatment. This can be accomplished with dialysis membranes which guarantee sufficient clearance for this molecule. It is a matter of discussion whether removal of β2-m by dialysis may be able to prevent secondary amyloidosis.

Methods

The dialyzers Diacap HI PS 15 (B. Braun Melsungen) and F70 S (Fresenius Medical Care) were compared in five anuric dialysis patients. Arterial blood was taken at the start and at the end of dialysis. Dialysate samples were taken after 30 and 210 minutes and filtrate samples after 60 and 240 minutes from the start of dialysis. β2-m and total protein concentration were measured in plasma, filtrate and dialysate. SDS-PAGE of proteins in the filtrate was carried out and kinetics of β2-m (Kt/Vβ2-m) were calculated using the Stiller/Mann model (4, 5).

Results

In both dialyzers β2-m is detectable at any time in the dialysate leaving the dialyzer. In the filtrate β2-m concentration is about 10 times higher than in the dialysate. Protein pattern in filtrate of both dialyzers is similar and corresponds to that of the glomerulum filtrate. β2-m reduction ratio is slightly lower than urea reduction ratio. Using both dialyzers Kt/Vβ2-m was 0.80, removing about 60% of the generated β2-m.

Conclusions

In both dialyzers there is considerable removal of β2-m. Examination of β2-m kinetics showed an optimum of Kt/Vβ2 of 0.80 which can not be surpassed. Only 60% of generated β2-m can be removed by three times per week hemodialysis therapy using high-flux dialyzers.
Coencapsulation of Hepatocytes and Bone Marrow Stem Cells: In Vitro Conversion of Ammonia and in Vivo Lowering of Bilirubin in Hyperbilirubemia Gunn Rats
Authors: Liu Z.C. , Chang T.M.S.
Published: January 2018

Backgrounds/aims

This study investigates the ammonia removal capacity of coencapsulated hepatocytes and bone marrow stem cells in culture, and the treatment effect on hyperbilirubinemia Gunn rats when transplanted.

Methods

The hepatocytes and bone marrow stem cells isolated from Wistar rats were encapsulated alone or coencapsulated. In vitro, the encapsulated cells were cultured in media supplemented with 2.4 mMol/L concentration of ammonium chloride and the ammonia removal and urea synthesis were evaluated. In vivo, the encapsulated cells were transplanted intraperitoneally into hyperbilirubinemia Gunn rats and plasma bilirubin levels were measured before and after transplantation at intervals of 85 days.

Results

The ammonia removal capacity was maintained longer in the different ammonia concentration media in the coencapsulated hepatocytes and bone marrow cells culture. In the coencapsulation transplantation group, the plasma bilirubin levels were significantly lower than those in the group of hepatocytes encapsulation transplantation during the period of 3 to 10 weeks posttransplantion.

Conclusions

The coencapsulated heaptocytes and bone marrow cells when compared to encapsulated hepatocytes could improve the maintenance of hepatocyte function both in vitro of ammonia removal in culture, and in vivo of the lowering the Gunn rats blood total bilirubin when transplanted.
Proliferation of Myocytes on Different ECM-Components of Animal/Human Origin in Vitro
Authors: Falkner E. , Kapeller B. , Eberl H. , Frick W. , Losert U.M. , Macfelda K.
Published: January 2018

For the purpose of tissue regeneration gels of reconstitued basement membrane have been suggested as a vehicle to transfer autologous cells. Results do look promising, but it should be considered that extracellular matrix (ECM) gel (Matrigel™) is a soluble extract of Engelbreth-Holm-Swarm (EHS) mouse tumor: Therefore objections arising concerning possible risks complicate clinical use in human subjects. Aim of this study was to determine whether ECM-components of human origin can be used as substitutes for tissue engineering tasks as proposed previously (1). Proliferation capability and viability of primary rat myocytes and rat myocyte cell lines were determined on days 1, 2, 4 and 8 after inocculation of the cells. Pooled data suggest that an appropriate combination of human ECM and human Collagen Type IV may represent an approach with good prospects.
Structural Changes in Silicon Rubber Peritoneal Dialysis Catheters in Patients using Mupirocin at the Exit Site
Authors: Khandelwal M. , Bailey S. , Izatt S. , Chu M. , Vas S. , Bargman J. , Oreopoulos D.
Published: January 2018

Structural damage to polyurethane PD (peritoneal dialysis) catheters in patients using mupirocin ointment is widely appreciated, but damage to silicon rubber PD catheters is less well described. Ten catheters (6.6%) out of 152 were found to have structural alterations such as opacification, ballooning, thinning, and rupture. The duration of PD in these 10 patients ranged from 23 months to 80 months (mean duration 51.1 months). The frequency of mupirocin application varied from daily (2 cases) to 2–3 times per week (7 cases). In eight catheters opacification occurred at the exit site whereas one catheter showed opacification midway between the exit site and the titanium adaptor. One catheter showed opacification, ballooning, and thinning at the exit site ruptured in the form of two slit-like openings. In conclusion, various structural changes such as opacification, ballooning or thinning were seen in 6.6% of silicon rubber PD catheters in patients using mupirocin at the exit site. Although the mechanism remains elusive, mupirocin or the antiseptic solution alone or in combination may be contributory. We believe that this is an under-reported complication and encourage other health care givers to incorportate a search for such changes during clinic visits.
Continuous Flow Peritoneal Dialysis: A New Double Lumen Catheter
Authors: Ronco C. , Dell'Aquila R. , Bonello M. , Gloukhoff A. , Amerling R. , Cruz C. , Levin N.
Published: January 2018

Continuous flow peritoneal dialysis (CFPD) is a therapy originally utilized in the sixties. It was then abandoned because of technical reasons, but, today, a new interest in this technique is emerging, because of new technical solutions and new hardware capabilities. CFPD is a peritoneal dialysis technique in which a certain amount of fluid is maintained in the peritoneal cavity, while a continuous inflow and outflow is provided via twin catheters or through a double lumen catheter. In this paper a new double lumen catheter is presented. The catheter is characterized by the presence of a diffuser in the inflow lumen, while a standard coiled shape characterizes the outflow lumen. The diffuser allows the use of high dialysate flows without peritoneal damage and with an excellent distribution of the fluid. The other feature of the catheter is the removable hub which allows for an easy subcutaneous tunneling of the catheter with a subsequent connection to the y segment. The special shape also guarantees a minimum recirculation during treatment. Data obtained in the first implanted catheter showed a progressive increase in small solute clearances in relation to an increase of the flow and the tidal volume in the peritoneal cavity. In particular, urea clearances up to 48 ml/min and creatinine clearances up to 39 ml/min were obtained. No major complications were observed after one year of use of the catheter.
Seasonal Variations of Chronic Hemodialysis Dose in South Croatia
Authors: Kovacic V. , Roguljic L.
Published: January 2018

Introduction

The dialysis parameters are used for prescribing the dose of dialysis therapy. Delivered dialysis dose could be calculated from predialysis and postdialysis blood urea concentrations. Seasonal variations in some clinical and laboratory variables occur among chronic hemodialysis patients. Seasonal variations in chronic hemodialysis dose have not been investigated. We prospectively compared hemodialysis adequacy parameters in order to demonstrate its seasonal differences.

Subjects and methods

Data were processed on 201 single dialysis treatments involving a group of 51 anuric chronic hemodialysis patients. The study period was 12 months. Four measurements per subject were obtained (in January, April, July, and October).

Results

We could not demonstrate seasonal variability in prescribed and delivered hemodialysis dose, in “delta” values (absolute differences between prescribed and delivered dialysis doses for the same hemodialysis treatment), or in ultrafiltration per hemodialysis. Seasonal differences were found in blood urea concentrations before and after hemodialysis (p=0.001, p=0.010). When the data were grouped into two groups: cold (January and October) and mild (April and July) months; we could not demonstrate significant differences in dialysis adequacy parameters, but there were differences in blood urea concentration before hemodialysis (26.06±14.73 vs. 24.35±4.50, p=0.004), blood urea concentration alter hemodialysis (10.24±2.96 vs. 9.43±2.60, p=0.019), and ultrafiltration per hemodialysis (3.36±1.13 vs. 3.10±1.11, p=0.046).

Conclusion

Based of the results of this investigation conducted on chronically hemodialyzed patients in the mild Mediterranean climate in South Croatia, Europe; we have concluded that clinicians should not pay attention to season when they prescribe hemodialysis dose or analyze delivered hemodialysis dose.
Preadipocyte-Loaded Collagen Scaffolds with Enlarged Pore Size for Improved Soft Tissue Engineering
Authors: Von Heimburg D. , Kuberka M. , Rendchen R. , Hemmrich K. , Rau G. , Pallua N.
Published: January 2018

Extended soft tissue defects after extensive deep burns or tumor resections are still an unresolved problem in plastic and reconstructive surgery. There is a clinical need for an adequate solution to this problem but currently, no adequate implant material is available for the correction of these defects. Since the autologous transplantation of mature adipose tissue gives poor results, this study explores the advantages of using human preadipocytes in collagen sponges for tissue reconstruction purposes.

Human preadipocytes of young adults were isolated, cultured, seeded onto collagen sponges with uniform pore size, and implanted into immunodeficient mice. After 24 hours of incubation in vitro and after explantation at 3, 8, and 12 weeks, sponges were examined for macroscopic appearance, weight, thickness, histology, immuno-histochemistry, and ultrastructure.

We find good penetration of cells into the scaffold, layers of adipose tissue, and new vessels on all grafts while controls appear unchanged. These results are promising for improving the reconstruction of soft tissue defects.
Robln Heart 2003 - Present State of the Polish Telemanipulator Project for Cardiac Surgery Assistance
Authors: Nawrat Z. , Podsędkowski L. , Mianowski K. , Wróblewski P. , Kostka P. , Pruski R. , Małota Z. , Religa Z.
Published: January 2018

The Polish telemanipulator (RobIn Heart), for use in cardiac surgery, has been realized by the Foundation of Cardiac Surgery Development in Zabrze, Poland, in cooperation with specialists from the Technical University of Lodz and Warsaw University of Technology. The brief history of robotic surgery and fundamental advantages of employing robots in this field – safe, reliable and repeatable operative results with less patient pain, trauma and recovery time – follow the assumptions of the Polish Cardio-Robot project.

The cardiac surgery robot, RobIn Heart, is an original construction with a segment type structure which allows the various combination of its parts for different types of surgery. The telemanipulator for cardiac surgery will consist of two arms equipped with tools and one arm holding the camera. Several models suitable for surgeon contact systems, using the experience of centers designing the artificial hand and haptic systems have been worked out. The detailed mechanical analysis and original construction of main parts of the robot and development of the surgical planning system are presented in further sections.
Endovascular Stents: Market Vigilance and Risk Factors
Authors: Grigioni M. , Daniele C. , Abbate M. , D'avenio G. , Morbiducci U. , Del Gaudio C. , Barbaro V.
Published: January 2018

With the aim of enhancing the safety and reliability level of coronary stents, we analyzed data collected from accident reports drawn from the MAUDE database (Manufacturer and User Facility Device Experience Database) of the FDA from 1996 to 2000. This analysis allowed us to highlight problems related to the use of coronary stents by means of the analysis of these reports at different levels, beginning from the causes that can lead to a certain type of accident up to the possible complication related to that event. Moreover we analyzed the procedure outcomes in terms of stent position inside the patient's body and the possible therapies adopted to solve the problems. The results showed that the most probable event that can lead to an accident is the stent separation from the balloon which, alone, turns up in a number of cases equal to the sum of all the others.

This result highlights the importance of the technical skill of the operators accomplished by special training and of the importance of clarity and completeness in the instructions for the use of the device. Another critical point is the reliability of the device which must guarantee an adequate safety level when it is used according to the instructions.
Adhesion and Function of Rat Liver Cells Adherent to Silk Fibroin/Collagen Blend Films
Authors: Cirillo B. , Morra M. , Catapano G.
Published: January 2018

Collagen is often used in bioartificial livers as a biomimetic coating to promote liver cell adhesion and differentiation. Animal proteins are expensive and expose the host to risks of cross-species infection due to contamination with prions. Silk fibroin (SF) is a biocompatible protein produced by Bombyx mori silk worms and possibly an alternative to collagen. We prepared SF-collagen blend films with different SF content adherent to the bottom of standard tissue culture dishes, and characterized their surface morphology by SEM, their wettability and examined them for their capacity to support rat liver cell adhesion and metabolism. Cell metabolism was characterized by estimating the rate at which cells eliminated ammonia and synthesized urea for up to 48h of culture. SF-containing films were smooth, clear and more wettable than collagen. Cells readily adhered, formed junctions and small size aggregates on all films. As many cells adhered on SF as on collagen films. Cell adhesion to high collagen content blend films could not be reliably estimated because cells dwelt in the large cavities in the film. The effect of SF on cell metabolism differed with the investigated metabolic pathway. However, cells on SF-containing films eliminated ammonia and synthesized urea at rates generally comparable to, for urea synthesis at times higher than, that of cells on collagen. These results suggest that silk fibroin is a suitable substratum for liver cell attachment and culture, and a potential alternative to collagen as a biomimetic coating.