Microbiological assessment of arterial allografts processed in a tissue bank.

The transmission of microbial infection through tissue allografts is one of the main risks that must be controlled in tissue banks. Therefore, microbiological monitoring controls and validated protocols for the decontamination of tissues during processing have been implemented. This study is based on the evaluation of data from microbiological cultures of arteries (mainly long peripheral arteries) processed in the tissue bank of Valencia (Spain). Donors' profile, pre- and post-disinfection tissue samples were assessed. The presence of residual antibiotics in disinfected tissues was determined and the antimicrobial potential of these tissues was tested. Our overall contamination rate was 23.69%, with a disinfection rate (after antibiotic incubation) of 87.5%. Most (76.09%) of the microbial contaminants were identified as Gram positive. Arterial allografts collected from body sites affected by prior organ removal showed higher risk of contamination. Only vancomycin was detected as tissue release. The antimicrobial effect on Candida albicans was lower than that for bacterial species. Risk assessment for microbial contamination suggested the donor's skin and the environment during tissue collection as the main sources for allograft contamination. Antibiotic-disinfected arterial allografts showed antimicrobial potential.

Risk assessment of arterial allograft contamination from tissue donors colonized by Candida auris.

BACKGROUND: Microbiological contamination is one of the main risks that must be controlled in tissue banking practices. For this reason, strict donor selection criteria are applied, disinfection protocols are used, and microbiological monitoring is performed at various stages. AIM: To detect Candida auris in arterial allografts and assess its origin. METHODS: Data on two multi-tissue donations with positive microbiological cultures for C. auris were analysed. Risk factors for microbiological contamination were assessed at procurement, processing and post storage. FINDINGS: C. auris was only isolated in cultures from arteries, and was not detected in cultures from cornea, musculoskeletal tissue or skin (even in the axillary-rectal sample taken from one donor). CONCLUSION: The donor's own skin was identified as the most likely source to explain the contamination of arteries by C. auris. Due to the pathogenicity of this fungus and difficulties associated with its correct identification, the implementation of measures for its detection in tissue donations is recommended.

Nanofibrillar cellulose wound dressing in skin graft donor site treatment.

BACKGROUND: Although new therapeutic approaches for burn treatment have made progress, there is still need for better methods to enhance wound healing and recovery especially in severely burned patients. Nanofibrillar cellulose (NFC) has gained attention due to its renewable nature, good biocompatibility and excellent physical properties that are of importance for a range of applications in pharmaceutical and biomedical fields. In the present study, we investigated the potential of a wood based NFC wound dressing in a clinical trial on burn patients. Previously, we have investigated NFC as a topical functionalized wound dressing that contributes to improve wound healing in mice. METHODS: Wood based NFC wound dressing was tested in split-thickness skin graft donor site treatment for nine burn patients in clinical trials at Helsinki Burn Centre. NFC dressing was applied to split thickness skin graft donor sites. The dressing gradually dehydrated and attached to donor site during the first days. During the clinical trials, physical and mechanical properties of NFC wound dressing were optimized by changing its composition. From patient 5 forward, NFC dressing was compared to commercial lactocapromer dressing, Suprathel® (PMI Polymedics, Germany). RESULTS: Epithelialization of the NFC dressing-covered donor site was faster in comparison to Suprathel®. Healthy epithelialized skin was revealed under the detached NFC dressing. NFC dressing self-detached after 11-21days for patients 1-9, while Suprathel® self-detached after 16-28days for patients 5-9. In comparison studies with patients 5-9, NFC dressing self-detached on average 4days earlier compared with Suprathel®. Lower NFC content in the material was evaluated to influence the enhanced pliability of the dressing and attachment to the wound bed. No allergic reaction or inflammatory response to NFC was observed. NFC dressing did not cause more pain for patients than the traditional methods to treat the skin graft donor sites. CONCLUSION: Based on the preliminary clinical data, NFC dressing seems to be promising for skin graft donor site treatment since it is biocompatible, attaches easily to wound bed, and remains in place until donor site has renewed. It also detaches from the epithelialized skin by itself.

Caracterización molecular de células progenitoras del parénquima subcortical cerebral humano adulto / Molecular characterization of progenitor cells from subcortical parenchyma of adult human brain

Objetivo: Caracterizar los patrones de expresión de marcadores de indiferenciación y diferenciación y las alteraciones morfológicas de las células progenitoras procedentes de parénquima cerebral humano adulto a lo largo de los pases en cultivo, evaluando su potencial para ser empleadas como fuente de progenitores de oligodendrocitos. Materiales y Métodos: Las células progenitoras se aislaron a partir de dos muestras obtenidas de pacientes sometidos a exéresis temporal por epilepsia. Para comprobar la evolución de los niveles de expresión de marcadores moleculares de diferenciación e indiferenciación en dichas células, se procedió a la extracción de ARNm en cada pase y a su estudio mediante RT-PCR. Se llevó a cabo un análisis de su capacidad proliferativa mediante inmunocitoquímica y un estudio de la evolución morfológica mediante microscopía. Resultados: Las células mostraron capacidad proliferativa durante los primeros pases en cultivo. Además, detectamos la expresión de marcadores de indiferenciación y diferenciación temprana a oligodendrocitos. Conclusión: Las células progenitoras aisladas de parénquima subcortical de cerebro humano pueden ser susceptibles de diferenciación a oligodendrocitos maduros, aunque en protocolos de diferenciación sólo deberían utilizarse pases tempranos (AU)

Objetive: characterize the behavior of progenitor cells isolated from subcortical parenchyma of human brain in culture. We have analyzed the changes in expression patterns of differentiation/undifferentiation markers as well as cell morphology along the passages and evaluated the potential to be further used as oligodendrocyte progenitors source. Material and Methods: We isolated progenitor cells from two different samples of subcortical parenchyma human brain of patients suffering from epilepsy. Cells were kept in culture until they became quiescent/senescent. Every other passages RNAs were isolated and checked for the expression of differentiation and undifferentiation markers by using RT-PCR. Proliferation was also addressed by RT-PCR and immunocytochemistry. We carried out cell morphology studies on semithin and ultrathin sections of cells. Results: We observed decreasing proliferative capacity of both two cell lines which became quiescent/senescent around passages 8-10. We detected the expression of either undifferentiation or early neural and oligodendrocytes differentiation markers. Conclusions: As for the expression of molecular markers, progenitor cells isolated from subcortical parenchyma of human brain have the potential to differentiate into mature oligodendrocytes (AU)

Short-gut syndrome: a new surgical technique and ultrastructural study of the liver and pancreas.

Massive (85%) resection of the small bowel was performed in 24 dogs to study a new surgical technique. In 12 dogs, two valves were created in the remaining small bowel at the same time, one proximal and the other distal to the anastomosis; the other 12 dogs constituted the control group. Biochemical tests, clinical evolution, and the weight curves show satisfactory results, with high survival, high lipid absorption, and low impairment of the overall condition. The valves can be created at the same time as the resection without any increase in the surgical risk. This new technique shows some possible advantages, and should be used in combination with total parenteral nutrition during the early stages and with basic diets thereafter. Ultrastructural alterations in the liver and pancreas have been studied in both groups.

[Acute mixed portal hypertension. Experimental study (author's transl)]. / Hypertension portale aiguë mixte. Une étude expérimentale.

Experimental studies were conducted in dogs to establish a new model for portal hypertension. The model chosen depends on partial obstruction of the portal vein to obtain a portal pressure of 11 +/- 4 ml. and the injection of 600 U. of secretin over a period of 35 min. The validity of the model was demonstrated by hemodynamic studies which resulted in a portal pressure, mesenteric blood flow, and mesenteric vascular resistances similar to those observed in clinical practice (hepatic cirrhosis).

Homograft of the small intestine. Metabolic and functional changes causing irreversible shock.

Homotransplantation of the small intestine is subject to high mortality in the first 48 hours after operation. We analyzed various causes of death, underlining the importance of postoperative shock, then developed an experiment in dogs with the object of improving the survival. We applied various therapeutic measures in order to reduce the factors which participate in the evolution of chronic, hypovolemic and toxic shock. We attempted to: (1) reduce the consecutive alterations to ischemia of the homotransplant during the non-perfusion period; (2) reduce the deleterious effect of retained fecal matter; (3) reduce the metabolic acidosis secondary to clamping of the great vessels; (4) acknowledge, analyze and correct alterations in fluid and electrolyte balances; (5) correct the blood volume; and (6) prevent infection. With these measures we have increased the survival rate.