ABSTRACT
Weighing is a key activity in every quality control laboratory as it is one of the first steps in the preparation of samples and reagents for most analytical procedures. It is also critical because weighing errors will add up and propagate throughout the whole analysis, affecting the accuracy and precision of the reported results. A new general chapter, Balances for analytical purposes (2.1.7), has recently been published in the European Pharmacopoeia (Ph. Eur.). This new text sets out clear requirements for an instrument that is essential to every analytical procedure described within the pages of the Ph. Eur. This article explains in detail these requirements and generally reviews the other quantity-related requirements present in Ph. Eur. texts.
Subject(s)
Laboratories , Europe , Quality Control , Reference StandardsABSTRACT
The influence of ionic strength up to 3 mol kg-1 (background electrolytes NaCl or CaCl2) on U(VI) sorption onto montmorillonite was investigated as function of pHc in absence and presence of CO2. A multi-method approach combined batch sorption experiments with spectroscopic methods (time-resolved laser-induced fluorescence spectroscopy (TRLFS) and in situ attenuated total reflection Fourier-transform infrared spectroscopy (ATR FT-IR)). In the absence of atmospheric carbonate, U(VI) sorption was nearly 99% above pHc 6 in both NaCl and CaCl2 and no significant effect of ionic strength was found. At lower pH, cation exchange was strongly reduced with increasing ionic strength. In the presence of carbonate, U(VI) sorption was reduced above pHc 7.5 in NaCl and pHc 6 in CaCl2 system due to formation of aqueous UO2(CO3)x(2-2x) and Ca2UO2(CO3)3 complexes, respectively, as verified by TRLFS. A significant ionic strength effect was observed due to the formation of Ca2UO2(CO3)3(aq), which strongly decreases U(VI) sorption with increasing ionic strength. The joint analysis of determined sorption data together with literature data (giving a total of 213 experimental data points) allowed to derive a consistent set of surface complexation reactions and constants based on the 2SPNE SC/CE approach, yielding log K°≡SSOUO2+ = 2.42 ± 0.04, log K°≡SSOUO2OH = -4.49 ± 0.7, and log K°≡SSOUO2(OH)32- = -20.5 ± 0.4. Ternary uranyl carbonate surface complexes were not required to describe the data. With this reduced set of surface complexes, an improved robust sorption model was obtained covering a broad variety of geochemical settings over wide ranges of ionic strengths and groundwater compositions, which subsequently was validated by an independent original dataset. This model improves the understanding of U(VI) retention by clay minerals and enables now predictive modeling of U(VI) sorption processes in complex clay rich natural environments.
Subject(s)
Bentonite , Uranium , Adsorption , Carbonates , Hydrogen-Ion Concentration , Osmolar Concentration , Spectroscopy, Fourier Transform Infrared , Uranium/analysisABSTRACT
A new (N2H4)WO3 compound has been obtained by mixing WO3 and aqueous hydrazine solution at room temperature for 24â h. The reaction is catalyzed by the presence of lithium. X-ray, synchrotron and neutron diffraction techniques have shown that the material crystallizes in trigonal space group P3221 (No. 154). Chains of distorted WO4 tetrahedra extend along the a axis of the unit cell, linked by a corner-sharing oxygen atom: the N2H4 are in the voids between them. The thermal characterization shows that this new compound is stable up to 220°C, greatly beyond the boiling point of N2H4 (114°C); thus making it a promising candidate for catalysis or trapping applications.
ABSTRACT
To investigate safety and efficacy of high-dose chemotherapy followed by autologous stem cell transplantation (HCT-ASCT) in relapsed/refractory (r/r) primary central nervous system lymphoma (PCNSL), we conducted a single-arm multicentre study for immunocompetent patients (<66 years) with PCNSL failing high-dose methotrexate)-based chemotherapy. Induction consisted of two courses of rituximab (375 mg/m2), high-dose cytarabine (2 × 3 g/m2) and thiotepa (40 mg/m2) with collection of stem cells in between. Conditioning for HCT-ASCT consisted of rituximab 375 mg/m2, carmustine 400 mg/m2 and thiotepa (4 × 5 mg/kg). Patients commenced HCT-ASCT irrespective of response after induction. Patients not achieving complete remission (CR) after HCT-ASCT received whole-brain radiotherapy. Primary end point was CR after HCT-ASCT. We enrolled 39 patients; median age and Karnofsky performance score are 57 years and 90%, respectively. About 28 patients had relapsed and 8 refractory disease. About 22 patients responded to induction and 32 patients commenced HCT-ASCT. About 22 patients (56.4%) achieved CR after HCT-ASCT. Respective 2-year progression-free survival (PFS) and overall survival (OS) rates were 46.0% (median PFS 12.4 months) and 56.4%; median OS not reached. We recorded four treatment-related deaths. Thiotepa-based HCT-ASCT is an effective treatment option in eligible patients with r/r PCNSL. Comparative studies are needed to further scrutinise the role of HCT-ASCT in the salvage setting.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Central Nervous System Neoplasms/pathology , Central Nervous System Neoplasms/therapy , Hematopoietic Stem Cell Transplantation , Lymphoma/pathology , Lymphoma/therapy , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Brain/diagnostic imaging , Brain/pathology , Central Nervous System Neoplasms/diagnostic imaging , Central Nervous System Neoplasms/mortality , Combined Modality Therapy , Drug Resistance, Neoplasm , Female , Hematopoietic Stem Cell Transplantation/adverse effects , Hematopoietic Stem Cell Transplantation/methods , Humans , Lymphoma/diagnostic imaging , Lymphoma/mortality , Male , Middle Aged , Prospective Studies , Recurrence , Retreatment , Transplantation, Autologous , Treatment OutcomeABSTRACT
In this retrospective multicentre study, we investigated the outcomes of elderly primary central nervous system lymphoma (PCNSL) patients (⩾65 years) who underwent high-dose chemotherapy followed by autologous stem cell transplantation (HDT-ASCT) at 11 centres between 2003 and 2016. End points included remission, progression-free survival (PFS), overall survival (OS) and treatment-related mortality. We identified 52 patients (median age 68.5 years, median Karnofsky Performance Status before HDT-ASCT 80%) who all underwent thiotepa-based HDT-ASCT. Fifteen patients (28.8%) received HDT-ASCT as first-line treatment and 37 (71.2%) received it as second or subsequent line. Remission status before HDT-ASCT was: CR 34.6%, PR 51.9%, stable disease 3.8% and progressive disease 9.6%. Following completion of HDT-ASCT, 36 patients (69.2%) achieved CR (21.2% first-line setting and 48.1% second or subsequent line setting) and 9 (17.3%) PR (5.8% first-line setting and 11.5% second or subsequent line setting). With a median follow-up of 22 months after HDT-ASCT, median PFS and OS were reached after 51.1 and 122.3 months, respectively. The 2-year PFS and OS rates were 62.0% and 70.8%, respectively. We observed two HDT-ASCT-associated deaths (3.8%). In selected elderly PCNSL patients, HDT-ASCT, using thiotepa-based conditioning regimes, is feasible and effective. Further prospective and comparative studies are warranted to further evaluate the role of HDT-ASCT in elderly PCNSL patients.
Subject(s)
Central Nervous System Neoplasms/therapy , Hematopoietic Stem Cell Transplantation/methods , Thiotepa/administration & dosage , Aged , Aged, 80 and over , Antineoplastic Agents, Alkylating/administration & dosage , Central Nervous System Neoplasms/mortality , Combined Modality Therapy , Disease-Free Survival , Europe , Hematopoietic Stem Cell Transplantation/mortality , Humans , Remission Induction , Retrospective Studies , Survival Analysis , Transplantation Conditioning/methods , Transplantation Conditioning/mortality , Transplantation, AutologousABSTRACT
A quantum spin liquid is a state of matter characterized by quantum entanglement and the absence of any broken symmetry. In condensed matter, the frustrated rare-earth pyrochlore magnets Ho2Ti2O7 and Dy2Ti2O7, so-called spin ices, exhibit a classical spin liquid state with fractionalized thermal excitations (magnetic monopoles). Evidence for a quantum spin ice, in which the magnetic monopoles become long range entangled and an emergent quantum electrodynamics arises, seems within reach. The magnetic properties of the quantum spin ice candidate Yb2Ti2O7 have eluded a global understanding and even the presence or absence of static magnetic order at low temperatures is controversial. Here we show that sensitivity to pressure is the missing key to the low temperature behaviour of Yb2Ti2O7. By combining neutron diffraction and muon spin relaxation on a stoichiometric sample under pressure, we evidence a magnetic transition from a disordered, non-magnetic, ground state to a splayed ferromagnetic ground state.
ABSTRACT
To investigate immuno-chemotherapy for elderly immuno-competent patients (⩾65 years) with newly diagnosed primary central nervous system lymphoma, we conducted a multicentre single-arm trial. One cycle consisted of rituximab (375 mg/m2, days 1, 15, 29), high-dose methotrexate (3 g/m2 days 2, 16, 30), procarbazine (60 mg/m2 days 2-11) and lomustine (110 mg/m2, day 2)-R-MPL protocol. Owing to infectious complications, we omitted lomustine during the study and consecutive patients were treated with the R-MP protocol. Three cycles were scheduled and repeated on day 43. Subsequently, patients commenced 4 weekly maintenance treatment with procarbazine (100 mg for 5 days). Primary end point was complete remission (CR) after 3 cycles. We included 107 patients (69 treated with R-MPL and 38 with R-MP). In all, 38/107 patients achieved CR (35.5%) and 15 (14.0%) achieved partial remission. R-MP was associated with a lower CR rate (31.6%) compared with R-MPL (37.7%), but respective 2-year progression-free survival (All 37.3%; R-MP 34.9%; R-MPL 38.8%) and overall survival (All 47.0%; R-MP 47.7%; R-MPL 46.0%) rates were similar. R-MP was associated with less ⩾grade 3 toxicities compared with R-MPL (71.1% vs 87.0%). R-MP is more feasible while still associated with similar efficacy compared with R-MPL and warrants further improvement in future studies.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Central Nervous System Neoplasms/drug therapy , Lymphoma/drug therapy , Aged , Aged, 80 and over , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Central Nervous System Neoplasms/diagnosis , Central Nervous System Neoplasms/mortality , Female , Humans , Immunologic Factors/administration & dosage , Lymphoma/diagnosis , Male , Methotrexate/administration & dosage , Neoplasm Staging , Proportional Hazards Models , Quality of Life , Remission Induction , Treatment Outcome , Tumor BurdenSubject(s)
Central Nervous System Neoplasms/immunology , HIV Infections/complications , Lymphoma, Non-Hodgkin/etiology , Stem Cell Transplantation/methods , Adult , Central Nervous System Neoplasms/drug therapy , Female , Humans , Lymphoma, Non-Hodgkin/drug therapy , Lymphoma, Non-Hodgkin/pathology , Male , Middle Aged , Treatment OutcomeABSTRACT
BACKGROUND: To investigate prognosis and effects of first-line therapy in elderly primary central nervous system lymphoma (PCNSL) patients. PATIENTS AND METHODS: A systematic review of studies about first-line therapy in immunocompetent patients ≥60 years with PCNSL until 2014 and a meta-analysis of individual patient data from eligible studies and international collaborators were carried out. RESULTS: We identified 20 eligible studies; from 13 studies, we obtained individual data of 405 patients, which were pooled with data of 378 additional patients (N = 783). Median age and Karnofsky Performance Score (KPS) was 68 years (range: 60-90 years) and 60% (range: 10%-100%), respectively. Treatments varied greatly, 573 (73%) patients received high-dose methotrexate (HD-MTX)-based therapy. A total of 276 patients received whole-brain radiotherapy (median 36 Gy, range 28.5-70 Gy). KPS ≥ 70% was the strongest prognostic factor for mortality [hazard ratio (HR) 0.50, 95% confidence interval (CI) 0.41-0.62]. After a median follow-up of 40 months, HD-MTX-based therapy was associated with improved survival (HR 0.70, 95% CI 0.53-0.93). There was no difference between HD-MTX plus oral chemotherapy and more aggressive HD-MTX-based therapies (HR 1.39, 95% CI 0.90-2.15). Radiotherapy was associated with an improved survival, but correlated with an increased risk for neurological side-effects (odds ratio 5.23, 95% CI 2.33-11.74). CONCLUSIONS: Elderly PCNSL patients benefit from HD-MTX-based therapy, especially if combined with oral alkylating agents. More aggressive HD-MTX protocols do not seem to improve outcome. WBRT may improve outcome, but is associated with increased risk for neurological side-effects. Prospective trials for elderly PCNSL patients are warranted.
Subject(s)
Antimetabolites, Antineoplastic/therapeutic use , Central Nervous System Neoplasms/drug therapy , Lymphoma/drug therapy , Methotrexate/therapeutic use , Aged , Central Nervous System Neoplasms/mortality , Humans , Lymphoma/mortality , Prognosis , Survival RateABSTRACT
BACKGROUND: High-dose chemotherapy followed by autologous stem-cell transplantation (HCT-ASCT) is a promising approach in eligible patients with primary central nervous system lymphoma (PCNSL). We report long-term data of patients who were treated according to HCT-ASCT containing protocols. PATIENTS AND METHODS: We analyzed survival and relapse rates in 43 (<67 years) immunocompetent patients with newly diagnosed PCNSL being treated according to two different high-dose methotrexate-based protocols followed by high-dose carmustine/thiotepa (BCNU/TT) plus ASCT (±whole brain irradiation). Analysis was conducted for all patients (intention-to-treat) and those patients who actually received HCT-ASCT (per-protocol). RESULTS: Thirty-four patients achieved complete remission, of those 12 relapsed (35%), while 6 of them relapsed 5 years after diagnosis. After a median follow-up of 120 months, median overall survival (OS) was reached after 104 months. Two- and 5-year OS was 81% and 70% and 2- and 5-year event-free survival (EFS) was 81% and 67%, respectively. In per-protocol analysis (N = 34), 5-year OS and EFS was 82% and 79%, respectively. HCT-ASCT associated related mortality was not observed. CONCLUSIONS: Sequential high-dose MTX containing chemotherapy followed by high-dose carmustine/thiotepa plus ASCT (±whole brain irradiation) is safe and leads to high survival rates in eligible patients with newly diagnosed PCNSL.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Central Nervous System Neoplasms/therapy , Lymphoma/therapy , Stem Cell Transplantation , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Carmustine/administration & dosage , Central Nervous System Neoplasms/drug therapy , Central Nervous System Neoplasms/surgery , Dose-Response Relationship, Drug , Female , Follow-Up Studies , Humans , Lymphoma/drug therapy , Lymphoma/surgery , Male , Middle Aged , Prognosis , Recurrence , Thiotepa/administration & dosageABSTRACT
BACKGROUND: Primary central nervous system lymphoma (PCNSL) is an aggressive extranodal non-Hodgkin lymphoma confined to the central nervous system. In this article, we report the results of a pilot trial adding rituximab to the established regimen consisting of methotrexate, procarbazine, and lomustine (R-MCP). DESIGN AND METHODS: PCNSL patients ≥65 years without Karnofsky performance score (KPS) limit were included. R-MCP regimen consisted of rituximab (375 mg/m(2) i.v. on days -6, 1, 15, and 29), methotrexate (3 g/m(2) i.v., days 2, 16, and 30) followed by folinic rescue, procarbazine (60 mg/m(2) orally, days 2-11), and lomustine (110 mg/m(2) orally, day 2). A maximum of three 43-day cycles were applied. Primary end point was response to treatment obtained by magnetic resonance imaging. Secondary end points were overall survival (OS) and progression-free survival (PFS). RESULTS: Twenty-eight patients were included (median age 75, median KPS 60%). Best documented response: complete remission in 18 of 28 (64%), partial remission in 5 of 28 (18%), stable disease in 1 of 28 (4%), and progressive disease in 2 of 28 (7%) patients. Response was not assessed in two patients. Two treatment-associated deaths were observed. After a median follow-up of 36 months, the 3-year PFS and OS was 31%. CONCLUSION: R-MCP regimen is well tolerated and active in elderly patients with newly diagnosed PCNSL.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Central Nervous System Neoplasms/therapy , Lymphoma, Non-Hodgkin/therapy , Age Factors , Aged , Aged, 80 and over , Antibodies, Monoclonal, Murine-Derived/administration & dosage , Antibodies, Monoclonal, Murine-Derived/adverse effects , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Central Nervous System Neoplasms/drug therapy , Central Nervous System Neoplasms/immunology , Combined Modality Therapy , Female , Humans , Lomustine/administration & dosage , Lomustine/adverse effects , Lymphoma, Non-Hodgkin/drug therapy , Lymphoma, Non-Hodgkin/immunology , Male , Methotrexate/administration & dosage , Methotrexate/adverse effects , Pilot Projects , Procarbazine/administration & dosage , Procarbazine/adverse effects , Rituximab , Survival AnalysisABSTRACT
BACKGROUND: It is critical to ensure that nurses have the skills and knowledge to respond effectively and to contribute to the psychosocial recovery of survivors of emergencies, particularly as an increasing proportion of the population is at risk of being exposed to a catastrophe. Over a decade ago it was reported that 16% of the world's population was at risk of experiencing some kind of catastrophic event. That has now risen with a total of 16% vulnerable to flood alone worldwide (Ministry of Health 2005). In the first semester of 2005, there were 174 natural disasters affecting 86 countries, resulting in the deaths of 5967 people, affecting a total of 60 million with an estimated damage of $6.3 billion (US$) (Centre for Research on the Epidemiology of Disasters 2005). AIM: To describe the nursing contribution to the psychosocial recovery of survivors of emergencies during the emergency preparedness and planning stage and in promoting recovery over the longer term. METHODS: Data for this article was sourced from relevant literature including World Health Organization policy and guidelines regarding mental health in emergencies. IMPLICATIONS FOR EDUCATION, TRAINING AND PRACTICE: It is vital that nurses realize they are too vulnerable to the effects of an emergency situation and that steps can be taken to protect nurses from enduring psychosocial effects.
Subject(s)
Emergencies , Nurse's Role , Stress Disorders, Post-Traumatic/nursing , Adolescent , Adult , Child , Counseling , Disaster Planning , Female , Humans , Stress, Psychological/nursingABSTRACT
In this work we investigate the electrical transport properties and growth conditions of tungsten carbon (WC) and palladium carbon (PdC) nanostructures on Si substrates using a focused ion beam and scanning electron microscope. In situ energy dispersive x-ray (EDX) characterizations reveal that electron-beam-induced WC and PdC nanostructure depositions (EBID) show a lower metal concentration (below 3% atomic percentage) than in ion-beam-induced deposition (IBID) (above 20%). In the case of PdC the growth pattern and the Pd/C content were optimized by adjusting the deposition temperature of the precursor material. In situ measurements of the resistivity of the nanostructures as a function of thickness reveal a minimum at a thickness approximately 200 nm. The lowest resistivity obtained for the PdC and WC structures is two orders of magnitude higher than the corresponding bulk values for pure Pd and W. The EBID samples show a non-metallic behaviour due to the low metal content. The temperature and magnetic field dependence of the IBID structures reveal a behaviour similar to disordered or granular conductors. The upper critical field and critical current density of the WC structures were measured below the superconducting critical temperature of approximately 5 K.
ABSTRACT
QUESTIONS UNDER STUDY: Swiss guidelines for the management of chronic obstructive pulmonary disease (COPD) were published in 2002. We aimed at assessing adherence to the proposed guidelines by the physicians in charge for all patients referred to our hospital for acute exacerbations of COPD over a one year period. METHODS: In a prospective observational study, data from a questionnaire and from records of all patients referred to our hospital with acute exacerbation of COPD were collected. Diagnostic steps as well as therapeutic and prophylactic interventions were reviewed. Where applicable, interventions were stratified according to proposed levels of evidence A-D. RESULTS: 45 patients in whom the diagnosis of COPD had been made before were included. Diagnosis was established by spirometry in 71%, in the remaining diagnosis was based on clinical grounds only. Non-smoking advice was given to 69%, and 16% were offered a nicotine-replacement trial (level A). Information about a disease management plan was given in 40% of the patients (level B), 22% had done a six minute walking distance test. 27% of the patients had participated in a pulmonary rehabilitation program (level A). 93% were on regular bronchodilator therapy (level B), and 56% had regular inhaled corticosteroids (level B). CONCLUSION: Confirmation of the diagnosis of COPD by spirometry is lacking in a significant number of patients. Most patients were treated with regular bronchodilators, however, relevant over-treatment with beta-adrenergic substances and overuse of inhaled corticosteroids in mild disease stages are common. Efforts for disease prevention and education as well as awareness of the potential benefits of pulmonary rehabilitation programs are still insufficient. Efforts to improve the adherence to the Swiss guidelines for the management of COPD should be intensified.
Subject(s)
Guideline Adherence , Practice Guidelines as Topic , Pulmonary Disease, Chronic Obstructive/diagnosis , Pulmonary Disease, Chronic Obstructive/therapy , Adrenal Cortex Hormones/therapeutic use , Aged , Bronchodilator Agents/therapeutic use , Drug Utilization/statistics & numerical data , Female , Hospitals, Teaching , Humans , Male , Nicotine/therapeutic use , Nicotinic Agonists/therapeutic use , Oxygen Inhalation Therapy/statistics & numerical data , Patient Education as Topic , Pneumonectomy/statistics & numerical data , Prospective Studies , Respiratory Function Tests , Smoking/epidemiology , Smoking Cessation , Surveys and Questionnaires , Switzerland/epidemiologyABSTRACT
Our purpose was to investigate side effects of sleep apnea treatment by removable oral appliances (OA) that advance the mandible. In 22 patients suffering from obstructive sleep apnea (OSA), questionnaire evaluations, polysomnographies, cephalographies, and dental plaster casts were obtained before initiation of treatment with OA that fully covered both dental arches. Patients were reevaluated after 3 to 12 mo (questionnaires, polysomnographies) and 12 to 30 mo (questionnaires, cephalographies, plaster casts) during continuous treatment. Polysomnographies confirmed improved breathing by OA. All patients experienced persistent alleviation of symptoms after 12 to 30 mo and wished to continue treatment. Side effects were common but only mildly disturbing: mucosal dryness (86% of patients), tooth discomfort (59%), and hypersalivation (55%). Cephalographies revealed a decrease in the mean (+/- SE) upper incisors to maxillary plane angle from 102 +/- 2 degrees at baseline, to 101 +/- 2 degrees after 12 to 30 mo (p < 0.05). Overbite and overjet were also slightly (mean reduction < 1 mm) but significantly reduced. None of these side effects required discontinuation of treatment. OA are an effective therapy of obstructive sleep apnea. Mild side effects are common but rarely require intervention. Nevertheless, close follow-up during long-term therapy by OA is advisable in order to timely detect potentially relevant orthodontic changes.
Subject(s)
Orthodontic Appliances/adverse effects , Sleep Apnea Syndromes/therapy , Snoring/therapy , Humans , Middle Aged , Orthodontic Appliance Design , Prospective Studies , Sleep Apnea Syndromes/etiology , Snoring/complicationsSubject(s)
Arm Injuries/etiology , Athletic Injuries/etiology , Fractures, Bone/etiology , Adult , Child , Humans , Risk FactorsABSTRACT
Non-surgical treatment of the sleep apnea syndrome comprises behavioral modification such as sleep hygiene, weight reduction, and positional training as an adjunct to standard therapy with continuous positive airway pressure (CPAP) applied via a nasal mask. For patients who cannot tolerate or are not willing to use CPAP for psychological or other reasons, removable intraoral appliances that advance the mandible during sleep are a valuable treatment alternative. Randomised controlled trials have confirmed effectiveness of intraoral appliances in relieving symptoms and measured sleep and respiratory disturbances. Side effects including hypersalivation, mucosal dryness, tooth and temporo-mandibular joint discomfort are common but usually mild. To timely detect effects of oral appliances on occlusion and on the temporo-mandibular joint longterm orthodontic monitoring is advisable.
Subject(s)
Jaw , Orthopedic Fixation Devices , Sleep Apnea, Obstructive/therapy , Humans , Positive-Pressure Respiration , Randomized Controlled Trials as Topic , Snoring/therapy , Treatment Outcome , Weight LossABSTRACT
A simple procedure is described for the extraction and purification of alginate from the inner stipes of the kelp Laminaria pallida. Alginate yield was about 10-15% of the dry mass, with a 70:30 mannuronic/guluronic acid ratio. Analysis of the purified alginate revealed a low polyphenol content while proteins were below detection level. The purified alginate was highly viscous, with 10-15 mPa s and 281 mPa s for a 0.1% and 0.5% solution, respectively, indicating a very high molecular mass (larger than 250 kDa). Bead formation occurred in the presence of divalent cations, but also in the presence of artificial serum (FCSIII) without added divalent cations. The biocompatibility of the alginate was tested with the in vitro mice lymphocyte test as well as by implantation of Ba2+ cross-linked beads beneath the kidney capsule of BB/OK rats. There was no evidence for significant mitogenic activity or fibrotic reaction. Biocompatibility of the alginate was also demonstrated by the encapsulation of human chondrocytes into Ca2+ cross-linked alginate beads. Immobilized chondrocytes grew and remained functional (i.e. they produced collagen).
Subject(s)
Alginates/chemistry , Biocompatible Materials/chemistry , Laminaria/chemistry , Alginates/isolation & purification , Alginates/pharmacology , Animals , Biocompatible Materials/isolation & purification , Biocompatible Materials/pharmacology , Cells, Cultured , Chondrocytes/drug effects , Chondrocytes/metabolism , Collagen/metabolism , Drug Compounding , Foreign-Body Reaction/pathology , Humans , Kidney/drug effects , Kidney/pathology , Lipopolysaccharides , Mice , Rats , Rats, Inbred BB , Transplantation, Heterologous , ViscosityABSTRACT
The redistribution of spin- or fluorescence-labeled phospholipid analogs across the plasma membrane of human osteoblast cells, either in suspension or grown as monolayers, was investigated. After incorporation into the outer membrane leaflet, analogs of the aminophospholipids phosphatidylserine and phosphatidylethanolamine moved rapidly to the inner monolayer, whereas the choline-containing analogs of phosphatidylcholine and sphingomyelin disappeared more slowly from the outer leaflet. The fast inward movement of the aminophospholipids became reduced after lowering the intracellular ATP, suggesting the presence of an aminophospholipid translocase activity in the plasma membrane of these cells. From these data, a transverse phospholipid asymmetry in osteoblasts can be inferred with the aminophospholipids mainly concentrated in the inner monolayer and the choline-containing phospholipids in the outer leaflet. A similar pattern of phospholipid internalization was inferred for osteoblasts from human osteoporotic bones and for a human osteosarcoma cell line. The relevance of the enrichment of phosphatidylserine in the cytoplasmic membrane leaflet for calcification in skeletal tissues is emphasized.