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Harvesting Procedure (harvesting + procedure)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Crystallization conditions and formation of orthorhombic paracetamol from ethanolic solution

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2002
N. Al-Zoubi
Orthorhombic paracetamol exhibits far better tabletability than the monoclinic form and its bulk crystallization from solution attracts much interest. In this study, temperature changes in supersaturated ethanolic solution have been recorded after seeding with orthorhombic crystals under different cooling temperatures (TC) and agitation rates (AR). Average cooling rate (CR), time for maximum temperature deviation (tmax) and area confined between curves of measured and reference temperature plots (AUC) were calculated and correlated with crystal yield (Y). The micromeritic (size and shape) and the compression properties, the density and the orthorhombic content of the crystalline product were evaluated and related to the main crystallization conditions applied (TC and AR). Conditions for optimal crystal yield and orthorhombic content were elucidated. It was found that crystal yield (Y) increased with AR and decreased with TC. The ratio tmax/CR provided good prediction of crystal yield (Y = 58.92 ,1.386 tmax/CR, r2 = 0.964 and P = 0.0001). TC and AR linearly affected crystal size and the size distribution, probably due to alterations in supersaturation, but they did not affect the crystal shape significantly. Density and compression properties (yield pressure and elastic recovery) were determined by the content of the orthorhombic form, which increased linearly with AR (P = 0.009) and with TC (P = 0.039) when agitation was between 300 and 500 rev min,1, while tmax decreased. At 700 rev min,1 orthorhombic content was maximized and became independent to TC. Higher orthorhombic content and crystal yield was expected for lower TC and for lower tmax, which corresponded to higher AR and might have also been affected by alteration of seeding and harvesting procedure. [source]

Preparation Techniques for the Injection of Human Autologous Cartilage: An Ex Vivo Feasibility Study,

THE LARYNGOSCOPE, Issue 1 2008
J Pieter Noordzij MD
Abstract Objectives: To determine the optimum donor site and preparation technique for injecting human autologous cartilage as a potentially permanent implant material for vocal fold medialization. Study Design: Prospective ex vivo experimental model. Methods: Human nasal septal and auricular cartilage was obtained from eight surgical cases after institutional review board approval. The auricle and nasal septum were chosen as potential donor sites because of ease of accessibility, volume of cartilage potentially available, and minimal subsequent cosmetic deformity after the tissue harvesting procedure. Various preparation techniques readily available in most operating rooms were tested for their efficacy in generating an injectable cartilage slurry. The various cartilage slurries were injected through sequentially smaller needles and examined cytologically. Results: The best injection properties for both nasal septal and auricular cartilage were obtained by drilling the cartilage down with a 5 mm otologic cutting bur, which allowed free passage through an 18 gauge needle. Cytologic examination of drilled septal cartilage showed good uniformity of cartilage pieces with a mean largest dimension of 0.44 ± 0.33 mm, and 33% of lacunae contained viable-appearing chondrocytes. Cytologic examination of drilled auricular cartilage was similar, exceptonly 10% of lacunae were occupied by chondrocytes. Other techniques tested (knife, morselizer, and cartilage crusher) did not yield injectable cartilage slurries. Conclusions: Both nasal septal and auricular cartilage can be prepared for injection via an 18 gauge needle using a cutting otologic bur. Further testing of in vivo viability and long-term volume retention is needed. [source]

The use of porous calcium phosphate scaffolds with transforming growth factor beta 1 as an onlay bone graft substitute

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2004
An experimental study in rats
Abstract Objectives: Autogeneous bone grafting is regarded to be the golden standard for onlay grafts, but it requires a harvesting procedure and the remodeling pattern over time is unpredictable. New materials are constantly being sought to overcome these problems. An in vivo experiment was carried out to evaluate whether (1) porous calcium phosphate cement is a suitable biomaterial for onlay bone grafting, and (2) the addition of transforming growth factor beta 1 (TGF-,1) accelerates de novo bone formation inside the cement porosity. Material and methods: A carrier of porous calcium phosphate cement (Calcibon®) was designed and 16 rats received one preshaped implant each. In 8 out of 16 implants 0.75 ,g TGF-,1 was applied. The animals were killed after 4 weeks and the characteristics of tissue ingrowth into the onlay graft were evaluated. Results: Histologic and quantitative histomorphometrical measurements demonstrated osteoid-like tissue formation in both experimental groups. The addition of TGF-,1 did not induce significantly more osteoid-like tissue formation. On the other hand, in TGF-,-loaded implants, a higher number of pores contained an inflammatory infiltrate. Conclusion: This study indicated that porous calcium phosphate cement is a promising material for clinical situations where bone formation has to be supported. Résumé La greffe osseuse autogène est considérée comme la meilleure technique actuelle pour les greffons onlay mais elle requiert un processus de prélevement et le remodelage qui s'en suit est imprévisible. De nouveaux matériaux sont donc constamment recherchés. Cette étude in vitro a essayé d'évaluer si 1) le cément phosphate calcium poreux était un biomatériel favorable pour le greffage osseux onlay, 2) si l'addition de TGF-,1 accélérait la néoformation osseuse à l'intérieur de la porosité du cément. Un porteur de cément phosphate calcium poreux (Calcibon®) a été fabriqué et seize rats ont reçu chacun un implant prédécoupé. Au niveau de huit des seize implants 0,75 ,g de TGF ,1 a été appliqué. Les animaux ont été euthanasiés après quatre semaines et les caractéristiques de la croissance interne tissulaire dans le greffon onlay ont étéévaluées. Les mesures histologiques et histomorphométriques quantitatives ont démontré une formation tissulaire semblable à l'ostéogénie dans les deux groupes expérimentaux. L'addition de TGF-ß1 n'induisait pas plus de formation tissulaire ressemblant à celle d'ostéogénie. D'un autre côté, dans les implants chargés de TGF-,1, un nombre plus important de pores contenaient un infiltrat inflammatoire. Cette étude indique que le cément phosphate calcium poreux est un matériau prometteur pour les situations cliniques dans lesquelles la formation osseuse doit être améliorée. Zusammenfassung Ziel: Die Transplantation von autologem Knochen wird heute als Goldstandard für die Onlay-Transplantate betrachtet. Es braucht dazu aber einen zusätzlichen Eingriff für die Entnahme und eine Prognose bezüglich der anschliessenden Remodellationsvorgänge sind kaum möglich. Man sucht ständig nach neuen Produkten, um diese Probleme zu überwinden. Man führte eine in vivo Studie durch und untersucht, ob (1) ein poröser Kalziumphosphatzement ein brauchbares Biomaterial für ein Onlay-Transplantat ist, und (2) der Zusatz von TGF-,1 die Neubildung von Knochen in den Porositäten des Zementes positiv beeinflusst. Material und Methode: Man entwickelte einen Trägerzement aus porösem Kalziumphosphat (Calcibon®) und 16 Ratten erhielten je ein vorgeformtes Implantat eingesetzt. Bei 8 der 16 Implantate fügte man zusätzlich 0.75 ,g TGF-,1 dazu. Vier Wochen später opferte man die Tiere und konnte nun die Charakteristika des in die Implantate einwachsenden Gewebes untersuchen. Resultate: Die histologischen und quantitativen histomorphometrischen Messungen zeigten in beiden experimentellen Gruppen osteoidähnliche Gewebsbildungen. Der Zusatz von TGF-,1 bewirkte keine signifikante Zunahme dieser osteoidähnlichen Gewebsbildungen. Die mit TGF-,1 durchsetzten Implantate enthielten aber mehr mit entzündlichem Infiltrat angefüllte Poren. Zusammenfassung: Diese Arbeit zeigte uns, dass ein poröser Kalziumphosphatzement bei klinischen Situationen, wo die Knochenbildung unterstützt werden muss, ein erfolgsversprechendes Material ist. Resumen Objetivos: El injerto de hueso autógeno está considerado como el estándar de oro para injertos superpuestos, pero requiere un procedimiento de recolección y el patrón de remodelado a lo largo del tiempo es impredecible. Constantemente se están buscando materiales nuevos para superar estos problemas. Se llevó a cabo un experimento in vivo para evaluar si (1) el cemento de fosfato cálcico poroso es un biomaterial apropiado para injerto óseo superpuesto, y (2) la adición de TGF-,1 acelera la formación de hueso de novo dentro de la porosidad del cemento. Material y Métodos: Se diseñó un portador de cemento de fosfato cálcico (Calcibon®) y 16 ratas recibieron un implante preformado cada una. En 8 de 16 implantes se aplicaron 0.75 ,g de TGF-,1. Los animales se sacrificaron tras 4 semanas y se evaluaron las características del tejido crecido hacia adentro del injerto superpuesto. Resultados: Las mediciones histológicas e histomorfométricas cuantitativas demostraron formación de tejido tipo osteoide en ambos grupos experimentales. La adición de TGF-,1 no indujo significativamente más formación de tejido tipo osteoide. Por otro lado, en los implantes cargados con TGF-,1, un mayor número de de poros contenían infiltrado inflamatorio. Conclusión: Este estudio indica que el cemento de fosfato cálcico poroso es un material prometedor para situaciones clínicas donde la formación de hueso ha de ser favorecida. [source]

Analysis of suspended sediment yields after low impact forest harvesting

HYDROLOGICAL PROCESSES, Issue 26 2007
Norifumi Hotta
Abstract Disturbances to forest catchments have profound effects on the environment of headwater streams and have an impact on suspended sediment (SS) management. Forest harvesting is a dominant factor in increasing SS yields. Road construction, skidder activity and ploughing associated with harvesting cause serious soil disturbance that results in SS increases. However, few studies have shown whether harvesting itself increases SS yields. This study examined how harvesting influenced SS yields in a steep forested area. During harvesting, soil surface disturbance was prevented as much as possible by using skyline logging treatments and piling branches and leaves at selected locations in the watershed. Using these methods, the representative SS rating curve did not change significantly after harvesting. The results also show that the characteristics of SS transport were related to the SS source area, and reveal that the riparian zone/stream bank was a dominant SS source area at the study site. Annual SS yields did not increase despite increasing annual water yields after harvesting. The limited water capacity of the soil at the study site likely led to only slight differences in pre- and post-harvest water discharge from heavy rainfall events. Most SS was transported during heavy rainfall events, and increases in SS yields were not detected after harvesting. We concluded that it is possible to prevent post-harvest SS increases by performing careful, low-impact harvesting procedures. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Haematological malignancies developing in previously healthy individuals who received haematopoietic growth factors: report from the Research on Adverse Drug Events and Reports (RADAR) project

BRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2006
Charles L. Bennett
Summary Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) and granulocyte colony-stimulating factor (G-CSF) promote haematopoietic progenitor cell maturation. We reviewed the findings for healthy volunteers/donors who developed haematological malignancies following PEG-rHuMGDF or G-CSF administration. Information was reviewed for three of 538 volunteers who received PEG-rHuMGDF in clinical trials and two of 200 donors who underwent G-CSF mobilised stem cell harvesting procedures for sibling stem cell transplants. Mantle cell, diffuse large B-cell lymphoma and chronic lymphocytic leukaemia were diagnosed 1,5 years after PEG-rHuMGDF exposure among three volunteers. For one patient, thrombocytopenia due to autoantibodies to PEG-rHuMGDF developed shortly after PEG-rHuMGDF administration and persisted until chemotherapy was administered. All three achieved complete remission, although one patient relapsed. Acute myeloid leukaemia was diagnosed 4 and 5 years after G-CSF mobilisation in two donors who underwent peripheral blood stem cell donation for sibling allogeneic haematopoietic stem cell transplantation. Following intensive chemotherapy, one died from acute leukaemia and the second is in complete remission. Controversy exists over the appropriateness of administering haematopoietic growth factors to healthy individuals. While a causal relationship with haematological malignancies cannot be demonstrated, long-term follow-up among healthy individuals who receive haematopoietic growth factors is needed. [source]