bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simple Method for Emax Evaluation: in Vitro Results
Authors: Ferrari G. , De Lazzari C. , Guaragno M. , Tosti G. , Mancini A.
Published: January 2018

Emax is an important parameter to evaluate the state of the heart and of its contractile capability. Its determination is not easy and rather inaccurate: However, it can be clinically relevant during mechanical and/or pharmacological heart assistance as it can suggest how to modify pharmacological therapy or the control strategy of the device.

Aim of this study is to develop a method based on ventricular energetics to evaluate Emax. If arterial elastance line slope is modified, for example by a slight peripheral resistance increase, Emax (assuming that it is constant) can be evaluated computing the energy transferred to the arterial elastance before and after the change. The corresponding equation contains known or easily computable variables and the difference Δ between end diastolic volume and ventricular rest volume. If the ratio of s before and after the disturbance is near to 1, the equation returns a fair estimation of Emax. The method was tested in vitro, in different circulatory conditions, using an open loop numerical model of the circulation built out of a variable elastance model of the ventricle connected to a modified windkessel representing the systemic arterial tree.

The results obtained in in vitro experiments suggest clinically testing this method.
Diffusive Clearance of Small and Middle-Sized Molecules in Combined Dialyzer Flow Configurations
Authors: Eloot S. , De Vos J-Y. , Hombrouckx R. , Verdonck P.
Published: January 2018

Clearance of low (LMW) and middle molecular weight (MMW) solutes was investigated in vitro for different dialyzer configurations and mutual flow directions. Single pass tests were performed with two low flux Fresenius F6HPS hemodialyzers placed in series (12 tests) and in parallel (6 tests), and results were compared with those for one single dialyzer (2 tests). Either high concentrated (45mS/cm) bicarbonate dialysis fluid (surrogate LMW) or trisodiumphosphate (surrogate MMW) concentration (31mS/cm) was used as blood substitution fluid. Standard blood and dialysate flows of 250 and 500ml/min, respectively, were prescribed. Clearance was derived from conductivity measurements in blood and dialysate compartment, correcting for the overall ultrafiltration rate of 0.1–0.5l/h. In a single dialyzer, changing the counter current flow to co-current deteriorates diffusive clearance by 14% (LMW) and 18% (MMW). Compared to one single dialyzer using counter current flow, clearance increases by 3 to 8% (LMW) and by 15 to 18% (MMW) using two dialyzers in parallel and in series, respectively. As a consequence, the benefit by using a second dialyzer is more prominent for larger molecules. Moreover, pressure profiles drawn for the different configurations show the impact of limited convection on diffusive clearance.
Maintenance of Residual Renal Function 10 Years after the Start of Hemodialysis: The Advantage of Tailored Schedules?
Authors: Piccoli G.B. , Burdese M. , Mezza E. , Consiglio V. , Mangiarotti G. , Thea A. , Bermond F. , Gai M. , Lanfranco G. , Jeantet A. , Segoloni G.P.
Published: January 2018

Maintenance of residual renal clearance is a clinical advantage, protecting against the long-term effects of uremia: although demonstrated in peritoneal dialysis, the strategies in hemodialysis are less clear. This case suggests that dialysis schedules individualized on the basis of renal clearances may help preserve residual function.

SB is a 58 year-old male who started dialysis in emergency (creatinine 30.7 mg/dL) in 1993. He had a history of gout, small shrunken kidneys and moderate hypertension. The clinical diagnosis was vasculointerstitial nephropathy. Eighteen months after starting hemodialysis on a conventional thrice weekly schedule, the patient was switched to 2 sessions/week (creatinine clearance increased to 6 ml/min). Thereafter, clearances were checked in alternate months and treatment was tailored to an equivalent renal clearance 12 ml/min (1–2 sessions, 2-3.30 hours/week). Ten years after beginning dialysis, he is on a twice weekly schedule (3.30 hours), is normotensive, works full-time and does not want to go on a transplant waiting list.
Efficacy of Immunoadsorbent Devices for Maintaining Hepatic Function in Ex Vivo Direct Xenogenic Hemoperfusion
Authors: Shindoh J. , Naruse K. , Sakai Y. , Makuuchi M.
Published: January 2018

We have developed a new system for direct xenogenic hemoperfusion of a bioartificial liver support system adopting two types of immunoadsorbent devices. In this study, we compared the efficacy of each immunoadsorbent device in maintaining porcine hepatocyte function during 3 h perfusion treatment in a canine liver failure model. Suppression of humoral immunity by the immunoglobulin adsorber prevented immunogenic hepatocyte injury more effectively, and the system showed higher hepatic function when compared with suppression of cell-mediated immunity by the leukocyte adsorber. However, single use of immunoglobulin adsorber was less effective in reducing patients' systemic ammmonia levels and modulating the Fischer's ratio compared with the case of combined use of both immunoadsorbent devices. These results suggest that suppression of humoral immunity was of primary importance in preventing immunogenic hepatocyte injury, however the adsorption of leukocytes may have a synergic effect on maintaining hepatocyte function in direct xenogenic hemoperfusion.
Morphological Analysis of in Vivo Velocity Field in the Alteration of the Vasomotor Tone
Authors: Grigioni M. , Daniele C. , Morbiducci U. , D'avenio G. , Di Benedetto G. , Barbaro V.
Published: January 2018

Vessel wall remodeling is involved in atherogenesis and in several important vascular diseases affecting mainly aged and prosthetic implanted patients. This adaptive response to pathological states in arterial hemodynamics strongly suggests that flow-derived stresses act as mechanical stimuli to the release of endothelium-derived vasoactive factors, leading to vascular alterations. As the correlation of intimal hyperplasia (IH) with blood flow alterations in arteries has been shown to be significant, and as it is well-known that clinical procedures carry a substantial risk of development of vascular disease, the relevance of local hemodynamics must be investigated to describe changes in compliance matching in prosthetic applications. The aim of our research is to investigate the use of principal components analysis, together with varimax rotation, in the individuation process of morphological characteristics of real time ultrasound in in vivo recordings of blood flow velocities, as provided by two different carotid perivascular manipulations. This would be of use in the clinical assessment of atherogenesis, hypertension, prosthetic replacement or more in general in all applications in which vascular tone may be impaired. Data recordings refer to previous animal experiments where the Moncada model was investigated by means of an ultrasound profilometer. The present study confirms the feasibility of the proposed analysis to follow vascular pathology evolution, distiguishing between an in progress and a static situation.
Cutaneous Plasmacytoma in a Hemodialysis Patient
Authors: Fabbian F. , Tessari G. , Colato C. , Cavallini L. , Martino F. , Ortalda V. , Loschiavo C. , Lupo A. , Maschio G.
Published: January 2018

Background

Extramedullary plasma cell dyscrasias are rare.

Case report

We report a case of a 56-year-old male Caucasian hemodialysis patient with cutaneous plasmacytoma. The diagnosis was made a few months after surgical removal of his renal graft due to chronic rejection. Investigations for the presence of an associated myeloma were negative. He underwent local radiotherapy with complete resolution of the skin lesion.

Conclusions

Nephrologists should be aware that the frequency of post-transplant lymphoproliferative disorders is increasing in the dialysis population, especially in those previously or currently treated with immunosuppressive drugs.
Hydrodynamic Stimulation and Long Term Cultivation of Nucleus Pulposus Cells: A New Bioreactor System to Induce Extracellular Matrix Synthesis by Nucleus Pulposus Cells Dependent on Intermittent Hydrostatic Pressure
Authors: Gokorsch S. , Nehring D. , Grottke C. , Czermak P.
Published: January 2018

A novel bioreactor system was constructed to induce extracellular matrix (ECM) synthesis by intervertebral disc (ID) cells due to intermittent hydrostatic pressure. The developed system is completely sterilizable and reusable. It is viable for cultivation, immobilization, and stimulation of various other cell types and tissues especially for cartilage. The custom made lid allows long-run cultivation through semi-continuous operation. Manual interferences and therefore the risk of contamination are reduced. Sampling, medium changing and addition of supplements are easily performed from the connected conditioning vessel, which could be placed in an incubator.

For the present investigations nucleus pulposus cells from pigs were taken and immobilized in agarose to obtain three-dimensional cell matrix constructs which were subjected to intermittent hydrostatic pressure. Afterwards the construct was biochemically examined. The proven constituents of ECM were found to be released in dependence of the magnitude and profile of the applied pressure.
No Genotoxicity of a New Nickel-Free Stainless Steel
Authors: Montanaro L. , Cervellati M. , Campoccia D. , Prati C. , Breschi L. , Arciola C.R.
Published: January 2018

Stainless steel is a metallic alloy largely employed in orthopedics, maxillofacial surgery and orthodontic therapy. However, the presence in its composition of a high quantity of nickel, an agent known to trigger toxic, allergic and cancerogenous responses in humans, is cause of some concern. In this study, we have investigated the in vitro mutagenicity and genotoxicity of a new nickel-free stainless steel, namely P558, in comparison to the conventional stainless steel AISI 316L. The cytogenetic effects were evaluated by studying the frequency of Sister Chromatid Exchanges (SCE) and chromosomal aberrations. Ames test was performed to detect the mutagenic activity. Both P558 and AISI 316L did not cause any significant increase in the average number of SCE and in chromosomal aberrations, either with or without metabolic activation. Furthermore, the Ames test showed that the extracts of both P558 and of AISI 316L are not mutagenic. Overall, these findings prove that P558 is devoid of genotoxicity and mutagenicity. The present results, together with other previous interesting observations that P558 promotes osseointegration, suggest that this new nickel-free stainless steel can represent a better alternative to other conventional steel alloys.
The Influence of X-ray Radiation on the Mineral/Organic Matrix Interaction of Bone Tissue: An FT-IR Microscopic Investigation
Authors: Hübner W. , Blume A. , Pushnjakova R. , Dekhtyar Y. , Hein H.-J.
Published: January 2018

Fourier transform infrared microscopy was used to investigate human cortical bone samples before and after treatment with increasing doses of X-ray radiation. Especially the spectral region of the v1 and v3 phosphate vibrations of hydroxyapatite, the main mineral component of bone, and the region of the amide I and amide II vibrational bands due to the collagen extracellular matrix were examined. Major spectral changes in the phosphate region between 1250–1000 cm–1 occur after irradiation doses between 1 and 4 Gray. These findings are explained by a decrease in size of mineral crystallites and by variances of the stoichiometric/non-stoichiometric apatite composition. The Ca2+/PO43-/HPO42- composition in the biological apatite is altered near the bone surface. The secondary structure of the collagen matrix is not affected by cumulative irradiation up to doses of 15 Gray as indicated by the unchanged frequency maximum and contour shape of the amide I band between 1600–1700 cm–1. However, side chain carboxylate groups of the collagen matrix that are involved in coordination with apatite bound calcium ions are partially removed by decarboxylation upon irradiation. Concomitantly, a loss of acidic phosphate groups due to a formation of phosphate groups with bound calcium is observed. These changes on a molecular level can be correlated with alterations in the mechanical properties of the bone samples, e.g. with an increased embrittlement as deduced from experiments with a scanning acoustic microscope (1).
Tissue Engineering Scheming by Artificial Intelligence
Authors: Xu J. , Ge H. , Zhou X. , Yang D.
Published: January 2018

Tissue engineers are often confused when seeking the most effective, economical and secure scheme for tissue engineering. The aim of this study is to generate tissue engineering schemes with artificial intelligence instead of human intelligence. The experimental data of tissue engineered cartilage were integrated and standardized with a centralized database, and a scheme engine was developed using artificial intelligent methods (artificial neural networks and decision trees). The scheme engine was trained with existing cases in the database, and then was used to generate tissue engineering schemes for new experimental animals. Following the schemes generated by the artificial intelligent system, we cured 18 of the 20 experimental animals. In conclusion, artificial intelligence is a powerful method for decision making in the tissue engineering realm.
Tissue Models of Peritoneal Fibrosis
Authors: Jiménez-Heffernan J.A. , Cirugeda A. , Bajo M.A. , Del Peso G. , Pérez-Lozano M.L. , Perna C. , Selgas R. , LÓpez-Cabrera M.
Published: January 2018

Objective

To evaluate the utility of peritoneal pathologic samples, unrelated to peritoneal dialysis (PD) treatment, for the study of peritoneal fibrosis and inflammation.

Methods

Comparative morphologic and immunohistochemical study of peritoneal pathologic samples unrelated to PD with peritoneal biopsies from PD patients with special emphasis on the expression of myofibroblastic and epithelial-to-mesenchymal transition markers.

Results

Regarding morphology, PD-related simple fibrosis was less cellular, with greater stromal hyalinization, determining a homogeneous, hypocellular aspect of the submesothelium. In contrast, non-PD fibrosis was more cellular with an extracellular matrix showing a dense and fibrillar quality with wide bundles of collagen. Hylinazing vasculopathy was only present in PD samples. Myofibroblastic differentiation and epithelial-to-mesenchymal transition were common findings in all situations of peritoneal fibrosis. Calponin and calretinin are useful cellular markers to study such fibrogenic mechanisms and correlate with other well-known markers such as α-SMA and cytokeratins. Their expression was much more intense in those samples showing acute inflammation (peritonitis).

Conclusions

Non-PD models of peritoneal fibrosis seem very useful to evaluate important features of human peritoneal pathology such us fibrogenesis, and inflammation. Fibrogenic events such as myofibroblastic differentiation and epithelial-to-mesenchymal transition are evident in these tissue samples allowing us to use them as an accessible source for in vivo and ex vivo studies. Both events show their maximal expression in situations of acute inflammation supporting the important role that peritonitis episodes play in the progression of fibrosis.
Simple Peritoneal Sclerosis and Sclerosing Peritonitis: Related or Distinct Entities?
Authors: Di Paolo N. , Sacchi G. , Garosi G. , Taganelli P. , Gaggiotti E.
Published: January 2018

Aim

The etiopathogenesis of sclerosing peritonitis is still debated, with some sustaining that it is a rare form of progression of simple peritoneal sclerosis and others that it is a primitive form. The aim of the present research was to clarify this question.

Material and Methods

438 peritoneal biopsies from 253 patients were re-examined. 174 were obtained prior to peritoneal dialysis and 224 after various periods of dialysis. Forty biopsies were from peritoneal dialysis patients who developed sclerosing peritonitis. Peritoneal morphology was studied for signs of transition from simple sclerosis to sclerosing peritonitis.

Results

Evidence was found sustaining the hypothesis that simple sclerosis to sclerosing peritonitis patients have distinct pathologies.

Conclusions

The results confirm previous observations, excluding the existence of any type of relation between simple peritoneal sclerosis to sclerosing peritonitis.
Atorvastatin Improves Peritoneal Sclerosis Induced by Hypertonic PD Solution in Rats
Authors: Duman S. , ŞEn S. , SÖZmen E.Y. , Oreopoulos D.G.
Published: January 2018

Background

Peritoneal sclerosis is a complication of peritoneal dialysis and results in ultrafiltration failure. It is related to chronic peritoneal injury due to dialysis solution content and recurrent peritonitis. Statins have anti-inflammatory properties which may be of value in modulating responses to injury. We evaluated the capacity of atorvastatin to modify peritoneal alterations secondary to hypertonic glucose.

Methods

Thirty-two non-uremic rats were divided into three groups: group I (Sham) rats received no treatment (n=11), group II received hypertonic (3.86%, 10 ml/day) PD solution (n=10) and group III received hypertonic PD solution (10 ml/day) plus 80 mg/L atorvastatin in drinking water (n=11). After four weeks, a one-hour peritoneal equilibration test (PET) was performed with 3.86% PD solution. Dialysate-to-plasma urea ratio (D/P urea), glucose reabsorption (D1/D0 glucose), ultrafiltration volume (UF), dialysate protein, TGF-ß1 and VEGF levels were determined.

Results

Administration of atorvastatin resulted in preserved UF (4.9±0.8 vs 7.5±0.6 mL, p <0.01), protein loss (2.2±0.2 vs 2.1±0.1 g/L, p >0.05), and peritoneal thickness (53±3 vs 26±4 μm, p <0.01). D1/D0 glucose was significantly reduced in the dextrose group (0.70±0.02 vs 0.56±0.04, p <0.01). Both higher levels of TGF-ß1 (206±40 vs 474±120 pg/mL, p<0.05), and VEGF in dialysate effluent (4±0.4 vs 7.9±3 pg/mL, p>0.05), was determined in the dextrose group.

Conclusion

Exposure to hypertonic glucose solution resulted in alterations in peritoneal transport manifested by a rapid dissipation of the glucose gradient and resultant impaired UF response. Administration of atorvastatin led to prevention of these alterations. We suggest that the anti-inflammatory properties of statins are useful in providing protection of the peritoneal membrane from the effects of hypertonic glucose.
Prevention of Peritoneal Sclerosis: A New Proposal to Substitute Glucose with Carnitine Dialysis Solution (Biocompatibility Testing in Vitro and in Rabbits)
Authors: Gaggiotti E. , Arduini A. , Bonomini M. , Valentini G. , Sacchi G. , Sansoni E. , Salvo D. , Di Paolo N.
Published: January 2018

Aim

Commercial glucose peritoneal dialysis solutions expose the peritoneum to hyperosmolar glucose containing variable amounts of non-enzymic breakdown products of glucose. These solutions are toxic for the peritoneum. The aim of the present study is to compare in vitro and in vivo characteristics of a new dialysis solution containing carnitine, a naturally occurring compound, as substitute of glucose.

Material and Methods

We compared in vitro and in the rabbit a new peritoneal dialysis solution containing carnitine, with two standard bicarbonate glucose peritoneal dialysis solutions and a solution containing icodextrin.

Results

In vitro and in vivo the solution containing carnitine seems to be more biocompatible than standard glucose solutions and those containing icodextrin.

Conclusions

In our study the peritoneal dialysis solution containing carnitine seems to prevent the mesothelial changes observed with solutions containing glucose. Since carnitine has been extensively studied and seems to be well tolerated by hemodialysis patients, even at high doses for long periods, clinical trials in humans may be planned in the near future.
Lamivudine in the Treatment of HBV-related Liver Disease after Renal Transplantation: An Update
Authors: Fabrizi F. , Martin P. , Bunnapradist S. , Villa M. , Rusconi E. , Messa P.G.
Published: January 2018

Diminished survival due to hepatitis B has been observed after renal transplantation (RT). Lamivudine, a second-generation nucleoside analogue, has been approved for the treatment of chronic hepatitis B virus (HBV) infection in patients with normal renal function. Numerous clinical experiences with lamivudine after RT have been recently published. Despite numerous shortcomings, all of these reports have shown encouraging results. The rate of clearance of HBV viremia ranged between 67% and 100%, and the frequency of ALT normalization was between 50% and 100% with lamivudine use. Even patients with fibrosing cholestatic hepatitis, a serious form of HBV-related liver disease with ominous course, have been successfully treated with lamivudine. Lamivudine therapy significantly improved the survival of HBsAg positive renal allograft recipients. However, numerous issues concerning the treatment of hepatitis B after RT remain unclear: the optimal time to initiate lamivudine, the appropriate duration of antiviral therapy after RT, and the role for pre-transplantation liver biopsy. Also, the management of lamivudine resistance remains a concern for physicians. Clinical trials are under way.
Low-dose Citrate Continuous Veno-venous Hemofiltration (CVVH) and Acid-base Balance
Authors: Naka T. , Egi M. , Bellomo R. , Cole L. , French C. , Wan L. , Fealy N. , Baldwin I.
Published: January 2018

Objective

To evaluate the acid-base effect of low-dose regional citrate anticoagulation (RCA) during continuous veno-venous hemofiltration (CVVH).

Design

Prospective observational study.

Setting

ICUs of tertiary public and private hospitals.

Subjects

Thirty critically ill patients with acute renal failure at risk of bleeding or with a major contraindication to heparin-CVVH and/or short filter life.

Methods

We used a commercial citrate-based fluid (11 mmol/L, sodium: 140 mmol/L, chloride: 108 mmol/L and 1 mol/L of potassium) as pre-dilution replacement fluid during CVVH. Further potassium was added according to serum potassium levels. We measured all relevant variables for acid-base analysis according to the Stewart-Figge methodology.

Results

Before treatment, study patients had a slight metabolic acidosis, which worsened over 6 hours of RCA-CVVH (pH from 7.39 to 7.38, p<0.005; bicarbonate from 23.2 to 21.6 mmol/L, p<0.0001 and base excess from −2.0 to −3.0 mEq/L, p<0.0001) due to a significant increase in SIG (from 5.8 to 6.6 mEq/L, p<0.05) and a decrease in SIDa (from 37.5 to 36.6 mEq/L, p<0.05). These acidifying effects were attenuated by hypoalbuminemia and a decrease in lactate (from 1.48 to 1.34 mmol/L, p<0.005) and did not lead to progressive acidosis. On cessation of treatment, this acidifying effect rapidly self-corrected within six hours.

Conclusions

Low dose RCA-CVVH induces a mild acidosis secondary to an increased strong ion gap and decreased SIDa which fully self-corrects at cessation of therapy. Clinicians need to be aware of these effects to correctly interpret changes in acid-base status in such patients.
New Fiber Configuration for Intravenous Gas Exchange
Authors: Cattaneo G.F. , Reul H.
Published: January 2018

Implantation of a membrane oxygenator (IO) into the vena cava for blood oxygenation in patients with acute lung failure has been researched for the last 25 years. Compared to the extra corporeal blood oxygenation, where blood is handled outside the body, IO doesn't present tubes, housings or heat exchangers, thus reducing considerably blood contact surface and setting priming volume to zero. Otherwise, restricted space in the vena cava and unadvantageous blood flow conditions represent so far a limitation for sufficient gas exchange. A new fiber configuration for intravenous use is being developed, which increases the implantable fiber surface and enhances gas exchange due to the increased blood convection. This is made possible by new fiber bundles, which are free to slide on a catheter and after implantation assume a twisted shape characterized by high homogeneity and fiber density.
Hemofiltration for Cytokine-Driven Illnesses: The Mediator Delivery Hypothesis
Authors: Di Carlo J.V. , Alexander S.R.
Published: January 2018

Hemofiltration is evolving as an adjunctive therapy for sepsis and other forms of systemic inflammation. Designed as a substitute for lost renal function, it is sometimes employed prior to the onset of renal failure to facilitate the nonspecific clearance of pro-inflammatory mediators. Prevailing theories suggest that hemofiltration attenuates the immune response when a threshold amount of excess cytokine is removed at the semi-permeable membrane. In this article we introduce an alternative hypothesis, in which hemofiltration exerts its effect by reinvigorating lymphatic flow and function. Crystalloid “replacement” solution, as much as 48 to 72 liters daily, is infused to restore intravascular volume lost through production of ultrafiltrate. Partial redistribution into interstitium and lymph mobilizes inflammatory mediators and other proteins, cellular byproducts, excessive ground matrix, fragments of apoptotic cells and free DNA. These substances are then metabolized, scavenged or cleared at multiple sites, including the reticuloendothelial system, liver, kidney, erythrocyte, and hemofilter.
PMEA Polymer-Coated PVC Tubing Maintains Anti-Thrombogenic Properties during in vitro Whole Blood Circulation
Authors: Yoshizaki T. , Tabuchi N. , Van Oeveren W. , Shibamiya A. , Koyama T. , Sunamori M.
Published: January 2018

Poly(2-methoxyethylacrylate) (PMEA) is a new coating material that appears to reduce protein and platelet adsorption. However, the exact performance of PMEA coated circuit remains to be revealed in well-controlled experiments. Therefore, we compared its hemocompatibility with covalent-bound heparin-, and non-coated circuits during 6 hours of in vitro circulation, using donor blood from six volunteers. In our model, simple tubing circuits containing one-way ball valve were placed on the rotary table, which moved alternatively to generate pulsatile recirculation of heparinized human blood inside the tubing. Using this model, we expected fine assessment of the material surface, because we could reduce blood damage by avoiding air and a blood pump. Moreover, the small capacity of circuit allowed us to compare three kinds of circuits using a single unit of donor blood, eliminating effects by possible variations between blood donors.

The anti-thrombin capacity of the PMEA-coated circuits was maintained even after six hours blood circulation, whereas surface thrombin generation increased markedly after use in non-coated circuits (P<0.05). Deposition of fibrin onto PMEA circuits was reduced more than 30% compared with heparin and non-coated circuits (P<0.05). However, the increase of plasma Factor XIIa was similar in all circuits. Increase of CD11b expression on circulating leukocytes and of plasma C3a was ameliorated in the heparin- and PMEA-coated circuits (P<0.05). PMEA-coated circuits appear to maintain their anti-thrombogenicity during use, otherwise PMEA-coated and heparin-coated circuits showed a similar character in hemocompatibility. This long-standing anti-thrombogenicity might be attributable to less adsorption of activated blood components onto the surface.
Shock Wave Therapy as an Innovative Technology in Skeletal Disorders: Study on Transmembrane Current in Stimulated Osteoblast-Like Cells
Authors: Martini L. , Giavaresi G. , Fini M. , Torricelli P. , Borsari V. , Giardino R. , De Pretto M. , Remondini D. , Castellani G.C.
Published: January 2018

Extracorporeal shock wave treatment (ESWT) is successfully used in various musculoskeletal disorders and pathologies. Despite the increasing use of this kind of therapy, some aspects of its mechanism of action are still unclear. In vitro bone cell behavior under ESWT were previously investigated by the present author and MG63 osteoblast-like cells showed an enhancement in proliferation and in the osteoblast differentiation after therapy with a low-energy flux density. The aim of the present study was to evaluate the effect of ESWT on the permeabilization of cell membrane. We characterized physiological changes in the MG63 associated with ESWT generated by an ESW device and patch clamp recording was performed to study ion channels. Experiments were carried out using the whole-cell recording configuration of the patch-clamp technique and the ionic current measurements were performed on cell samples of ESW treated and control groups. The patch-clamp technique showed the effect of ESWT on the amplitude of transmembrane currents. The treatment with ESW enhanced the transmembrane current as well the voltage dependence of Ca-activated and K channels that mediate these currents: the differences between treated cells and control at 80mV were over 1000 pA (P<0.05). These modifications of ion channels activity positively influence cell proliferation (MTT test, P<0.0001) without interfering with the normal synthesis activity of stimulated osteoblasts.
Plasma Acid-base Changes in Chronic Renal Failure: A Stewart Analysis
Authors: Story D.A. , Tosolini A. , Bellomo R. , Leblanc M. , Bragantini L. , Ronco C.
Published: January 2018

The bicarbonate centered approach to acid-base physiology involves complex explanations for the metabolic acidosis associated with chronic renal failure. We used the alternate Stewart approach to acid-base physiology to quantify the acid-base chemistry of patients with chronic renal failure. We examined the plasma and urine chemistry of 19 patients with chronic renal failure who were predialysis and 20 healthy volunteers. We compared the plasma strong-ion-difference due to sodium, potassium, and chloride ions as well as the weak acids albumin and phosphate. We used a simplified Fencl-Stewart approach to quantify the effects of sodium-chloride, albumin, and unmeasured ions on base-excess. The chronic renal failure group had a greater metabolic acidosis, with a base-excess that differed from the healthy group by a mean of −2.7 mmol/L, p= 0.04. This was associated with a strong ion acidosis due to both increased chloride and decreased sodium. The anion gap, strong-ion-gap, and base-excess effect of unmeasured ions were similar in both groups suggesting that unmeasured ions had only a minor role in the acid-base status in this group of patients.
Hyperviscosity Syndrome in Hematological Diseases and Therapeutic Apheresis
Authors: Accorsi P. , Passeri C. , Onofrillo D. , Iacone A.
Published: January 2018

The hyperviscosity syndrome classified into pleiocytosic, sclerotic and sieric syndromes according to the blood components involved are characterized by a different degree of clinical signs and symptoms related to rheological modification of blood. Therapeutic management of these syndromes is complex and the choice of apheresis treatment is generally restricted to emergency episodes in order to overcome the acute phase and to reverse the symptoms until definitive therapy is effective.
Biofilm in Implant Infections: Its Production and Regulation
Authors: Costerton J.W. , Montanaro L. , Arciola C.R.
Published: January 2018

A significant proportion of medical implants become the focus of a device-related infection, difficult to eradicate because bacteria that cause these infections live in well-developed biofilms.

Biofilm is a microbial derived sessile community characterized by cells that are irreversibly attached to a substratum or interface to each other, embedded in a matrix of extracellular polymeric substances that they have produced.

Bacterial adherence and biofilm production proceed in two steps: first, an attachment to a surface and, second, a cell-to-cell adhesion, with pluristratification of bacteria onto the artificial surface. The first step requires the mediation of bacterial surface proteins, the cardinal of which is similar to S. aureus autolysin and is denominated AtlE.

In staphylococci the matrix of extracellular polymeric substances of biofilm is a polymer of β-1,6-linked N-acetylglucosamine (PIA), whose synthesis is mediated by the ica operon. Biofilm formation is partially controlled by quorum sensing, an interbacterial communication mechanism dependent on population density.

The principal implants that can be compromised by biofilm associated infections are: central venous catheters, heart valves, ventricular assist devices, coronary stents, neurosurgical ventricular shunts, implantable neurological stimulators, arthro-prostheses, fracture-fixation devices, inflatable penile implants, breast implants, cochlear implants, intra-ocular lenses, dental implants.

Biofilms play an important role in the spread of antibiotic resistance. Within the high dense bacterial population, efficient horizontal transfer of resistance and virulence genes takes place.

In the future, treatments that inhibit the transcription of biofilm controlling genes might be a successful strategy in inhibiting these infections.
Etiology of Implant Orthopedic Infections: A Survey on 1027 Clinical Isolates
Authors: Arciola C.R. , An Y.H. , Campoccia D. , Donati M.E. , Montanaro L.
Published: January 2018

In spite of the recent achievements derived from modern protocols of prophylaxis, orthopedic surgical infections still remain unacceptably frequent, especially in light of the often devastating outcomes of septic complications. The spectrum and the prevalence of the bacteria most frequently involved in orthopedic infections are here explored, with particular reference to those infections associated to implant biomaterials, which were grouped based on device typology. During a 30 months period (from September 2000 to April 2003), 1027 microbial strains were consecutively isolated from 699 patients undergoing revision surgery at the Rizzoli Orthopedic Institute. 775 (75.5%) of all these microorganisms were identified as belonging to the Staphylococcus genus, 82 (8%) to the Enterobacteriaceae family, 75 (7.3%) to the Pseudomonas genus, 54 (5.3%) to the Enterococcus genus and 20 (1.9%) to the Streptococcus genus. While confirming the importance of staphylococci as the most diffuse cause of infection, our data indicate an unexpectedly high prevalence of S. epidermidis on infected hip and knee arthroprostheses, respectively of 42% and 44%. The spectrum of bacteria infecting either internal or external fracture fixation devices appears to differ from that of hip and knee arthroprostheses and more closely resembles that of infections non-associated to medical devices, being characterized by a relatively higher prevalence of Staphylococcus aureus (over 40%) and Pseudomonas aeruginosa. Enterobacteriaceae and members of the Streptococcus and Corynebacterium genera are frequently associated with implants in which surgical incisions were made near the perineum, determining a completely altered spectrum.
Effects of Sterilization on Implant Mechanical Property and Biocompatibility
Authors: An Y.H. , Alvi F.I. , Kang Q. , Laberge M. , Drews M.J. , Zhang J. , Matthews M.A. , Arciola C.R.
Published: January 2018

This article concisely reviews the effects of sterilization on the mechanical properties and surface chemistries of implantable biomaterials. This article also summarizes the biological effects of the sterilization-related changes in the implant. Because there are so many different types of implant materials currently in use (including metals, polymers, and diverse biological materials), the response of tissue to these different materials varies dramatically. This review further discusses the effects of sterilization on in vivo and in vitro tissue response specifically to implantable metals and polyethylene, with the possibility of future biocompatibility testing of the implants sterilized with supercritical phase carbon dioxide sterilization.
Antibiotic Resistance in Staphylococcus Aureus and Staphylococcus Epidermidis Clinical Isolates from Implant Orthopedic Infections
Authors: Campoccia D. , Montanaro L. , Baldassarri L. , An Y.H. , Arciola C.R.
Published: January 2018

In the last decade the rising phenomenon of resistance to most common antibiotic drugs among staphylococcal clinical isolates has been a reason for serious concern and alarm. The present study investigated the prevalence of antibiotic resistance within a large microbial collection including 530 clinical strains of S. aureus and 408 strains of S. epidermidis to a panel of 16 different drugs. All strains were isolated from orthopedic infections, either associated or non-associated with implant materials. Interestingly, our data show that the profile of the prevalence of antibiotic resistance within the two species of pathogens is extremely similar for the vast majority of the drugs screened. The only statistically significant variations in prevalence concerned, in order of relevance, the following 5 out of 16 antibiotics: sulfamethoxazole (in combination with trimethoprim), erythromycin, and, to a lesser extent, oxacillin, imipenem, and clindamycin. In the case of Staphylococcus aureus, the isolates associated to implant materials were found more frequently resistant to all 4 aminoglycosides screened as well as to ciprofloxacin.
Antimicrobial Agents and Catheter-Related Interventions to Prevent Peritonitis in Peritoneal Dialysis: Using Evidence in the Context of Clinical Practice
Authors: Bonifati C. , Pansini F. , Torres D.D. , Navaneethan S.D. , Craig J.C. , Strippoli G.F.M.
Published: January 2018

Background

Peritonitis still represents a common and major complication of peritoneal dialysis. The broader adoption of several strategies, including antimicrobial and catheter related interventions, has been advocated to prevent or reduce the risk of peritonitis in peritoneal dialysis.

Methods

In this article we start with the presentation of a clinical case where concern exists about the strategies for preventing peritoneal dialysis peritonitis. We then look at the available evidence in the form of systematic reviews of randomized trials and individual randomized trials of interventions to prevent peritonitis in peritoneal dialysis. A summary of the evidence is provided and then put in context with the clinical case scenario.

Results

Nineteen eligible trials (1949 patients) of antimicrobial agents and 37 (2822 patients) of catheter related interventions to prevent peritonitis in peritoneal dialysis were identified. Nasal mupirocin compared with placebo significantly reduced the exit-site and tunnel infection rate (1 trial, 2716 patient months, RR 0.58, 95% CI 0.40 to 0.85) but not peritonitis rate (1 trial, 2716 patient months, RR 0.84, 95% CI 0.44 to 1.60). As for antimicrobial strategies, perioperative intravenous antibiotics compared with no treatment significantly reduced the risk of early peritonitis (4 trials, 335 patients, RR 0.35, 95% CI 0.15 to 0.80) but not exit site and tunnel infection (3 trials, 114 patients, RR 0.32, 95% CI 0.02 to 4.81). As for catheter related strategies, Y-set and twin-bag systems were superior to conventional spike systems (7 trials, 485 patients, RR 0.64, 95% CI 0.53 to 0.77) and no other catheter-related intervention was demonstrated to prevent peritonitis in PD.

Conclusions

Evidence exists to support the use of perioperative intravenous antibiotic prophylaxis at the time of catheter placement, the twin-bag and Y-set system, as well as prophylaxis with mupirocin in Staphylococcus aureus nasal carriers. Despite lack of evidence, several other agents are used and recommended in major international guidelines, which is reasonable but requires further investigation.
Complications of Peritoneal Dialysis Catheters: Early and Late
Authors: Diaz-Buxo J.A.
Published: January 2018

The complications of peritoneal dialysis catheters are often due to errors made during the initial catheter insertion procedure. Other complications relate to the improper selection of the catheter type or size. Thus, many complications are preventable. This review summarizes the complications resulting from the insertion or presence of a PD catheter and classifies them as either early or late events. A short comment on early diagnosis and appropriate management is also provided.
The Toronto Western Hospital Catheter: One Center's Experience and Review of the Literature
Authors: Sikaneta T. , Cheung K.M. , Abdolell M. , Tam P. , Ting R. , Fung J. , Roscoe J. , Woods E. , Le Blanc D. , Oreopoulos D.
Published: January 2018

Background

We report our center's experience with the Toronto Western Hospital (TWH) catheter, and discuss our catheter survival and complication rates.

Methods

Retrospective chart review of patients receiving peritoneal dialysis therapy via a TWH catheter. Catheter complication rates of peritonitis, exit site infection, obstruction, leak, and malfunction were assessed. A catheter was considered failed if removed because of exit site infection, obstruction, or malfunction. All other catheters, even if removed for other reasons, were considered censured. Survival was defined as the period from insertion to failure or censure date, and reported using Kaplan Meier analysis.

Results

192 patients with a total of 208 TWH catheters (4,845.3 catheter months) were analyzed. Our overall 1- and 3-year catheter survival rates were identical at 0.9182. Our catheter complication rates (expressed as number of catheter months per event) were 31.3 for peritonitis, 42.9 for exit site infection, 72.3 for obstruction, 538.4 for malfunction, and 969.1 for catheter leak. Our findings were similar to those reported in the literature for TWH and other peritoneal catheters.
Why Bury the Distal end of the Peritoneal Dialysis Catheter
Authors: Moncrief J.W.
Published: January 2018

The first catheters for peritoneal dialysis were made in silicone with a Dacron cuff, which allowed tissue ingrowth, creating a barrier to the entrance of bacteria from the skin surface. However, the interruption of the skin envelope produces recurrent exit site and tunnel infections and peritonitis, which are the leading causes of discontinuing peritoneal dialysis. Experimental evidence suggests that the use of a double cuff silastic catheter and subcutaneous implantation of the distal catheter for 5–6 weeks before exposure reduces such infections, thus improving catheter life. Early preparation of peritoneal dialysis access with subcutaneous implantation allows healing of scar tissue into the cuffs and formation of an excellent bacteriological barrier.
Chronic Peritoneal Dialysis Catheters: Challenges and Design Solutions
Authors: Ash S.R.
Published: January 2018

Although highly successful as transcutaneous access devices, today's peritoneal dialysis catheters still have imperfect hydraulic function, biocompatibility and resistance to infection. Success of Tenckhoff catheters is greatly improved by the proper positioning of deep and subcutaneous cuffs and intraperitoneal segment. Newer peritoneal catheter designs are intended to improve hydraulic function, avoid outflow failure, and diminish exit site infection. These catheter designs serve as excellent alternatives for patients with various types of failure of Tenckhoff catheters. Catheters have been designed for Continuous Flow Peritoneal Dialysis, and have generally been successful in providing high peritoneal dialysis flow rate, but not always successful in optimally distributing flow of peritoneal fluid. Improvements in catheter design may expand the use of peritoneal dialysis as a successful home dialysis therapy.
Management of Fluid Overload in Congestive Heart Failure: Learning from a Case Report
Authors: Salvatori G. , Ronco F. , Bonello M. , Bottero M.
Published: January 2018

A case of refractory fluid overload due to congestive heart failure and consequent renal insufficiency is reported. The case was approached multidisciplinarily, at the beginning with conservative and pharmacological therapy, subsequently with extracorporeal fluid removal in which a specific attention was payed to the maintenance of circulating blood volume and achievement of dry weight, and finally with chronic peritoneal dialysis as a maintenance therapy. The case seems to summarize the pathway of many patients seen initially in intensive care and cardiology departments and subsequently in nephrological wards.
Formation of a Sheet-Shaped Organoid Using Rat Primary Hepatocytes for Long-Term Maintenance of Liver-Specific Functions
Authors: Ishihara K. , Mizumoto H. , Nakazawa K. , Kajiwara T. , Funatsu K.
Published: January 2018

In recent years, use of hepatocyte aggregates has led to development of a hybrid artificial liver support system (HALSS) that has high performance. However, in general, their thickness is 100 μm or more, and generation of a dead cell layer due to oxygen exhaustion inside the aggregates has been a universal problem. The present study proposes a novel organoid culture method with better performance than previous organoid culture methods by forming a sheet-shaped organoid (organoid-sheet) with a thickness of approximately 100 μm. The cell number of the organoid-sheet was maintained at approximately 75% of the initial number at 4 days of culture. On the other hand, that of a cylindrical organoid (cylindroid), which formed inside of a plasma separation hollow fiber with 285 μm inner diameter in our previous study, decreased to approximately 50% within 2 days. The ammonia removal rate of the cells in the organoid-sheet was higher than that of the cells in the cylindroid on the first day, but it decreased during the culture time. At day 15, the rate was reduced by almost 50% with respect to the value on the first day. The cells in the cylindroid displayed a lower ammonia removal rate. A significant difference was not observed between the albumin synthesis rates of the two cultures on the first day. However, over a period of time the cells in the organoid-sheet showed a higher albumin synthesis rate than cells in the cylindroid. As this novel organoid maintains these functions for at least 1 month, it is expected to be applied for the development of a HALSS with higher performance.
Emerging Staphylococcus Species as New Pathogens in Implant Infections
Authors: Von Eiff C. , Arciola C.R. , Montanaro L. , Becker K. , Campoccia D.
Published: January 2018

The vast use of prosthetic materials in medicine over the last decades has been accompanied by the appearance of new opportunistic pathogens previously considered incapable of causing infections with significant morbidity and/or mortality. In this regard, the genus Staphylococcus enlisting numerous species usually characterized by a saprophytic habit covers a special role. Apart from Staphylococcus aureus and Staphylococcus epidermidis, well known for their large prevalence in implant-related infections, a number of further staphylococcal species are progressively being indicated for their pathogenic potential. The increasing attention on these opportunistic bacteria is due to an ever growing number of clinical reports, which is also deriving from a more accurate identification of these species with currently available techniques. This synopsis intends to offer an overview on recently emerging coagulase-negative staphylococci (CoNS) as well as coagulase-positive/-variable staphylococci exhibiting distinct traits of virulence, pathogenicity, and epidemiologic impact depending among others on the medical field, the type of prosthetic device and its anatomic location.