RESUMEN
BACKGROUND: Acellular nerve allografts (ANA) recellularized with mesenchymal stem cells (MSC) or Schwann cells (SC) are, at present, a therapeutic option for peripheral nerve injuries (PNI). This study aimed to evaluate the regenerative and functional capacity of a recellularized allograft (RA) compared with autograft nerve reconstruction in PNI. METHODS: Fourteen ovines were randomly included in two groups (n=7). A peroneal nerve gap 30 mm in length was excised, and nerve repair was performed by the transplantation of either an autograft or a recellularized allograft with SC-like cells. Evaluations included a histomorphological analysis of the ANA, MSC pre differentiated into SC-like cells, at one year follow-up functional limb recovery (support and gait), and nerve regeneration using neurophysiological tests and histomorphometric analysis. All evaluations were compared with the contralateral hindlimb as the control. RESULTS: The nerve allograft was successfully decellularized and more than 70% of MSC were pre differentiated into SC-like cells. Functional assessment in both treated groups improved similarly over time (p <0.05). Neurophysiological results (latency, amplitude, and conduction velocity) also improved in both treated groups at twelve months. Histological results demonstrated a less organized arrangement of nerve fibers (p <0.05) with an active remyelination process (p <0.05) in both treated groups compared with controls at twelve months. CONCLUSIONS: ANA recellularized with SC-like cells proved to be a successful treatment for nerve gaps. Motor recovery and nerve regeneration were satisfactorily achieved in both graft groups compared with their contralateral nontreated nerves. This approach could be useful for the clinical therapy of PNI.
Asunto(s)
Traumatismos de los Nervios Periféricos , Nervio Ciático , Animales , Aloinjertos/fisiología , Regeneración Nerviosa/fisiología , Traumatismos de los Nervios Periféricos/cirugía , Células de Schwann/fisiología , Nervio Ciático/lesiones , Ovinos , Trasplante Homólogo/métodosRESUMEN
Silver physical developers consist of silver ions and a reducing (developing) agent. They were formulated for developing latent images on photosensitive materials such as photographic emulsions. The mechanism of how the latent image nuclei catalyze the reduction of silver ions by a reducing agent to form black colloidal silver particles has been extensively studied. These developers also happen to visualize latent prints on porous surfaces such as paper. Several hypotheses exist that identify the components in latent print residue that trigger physical development; also several hypotheses exist that explain why such developers work better on porous rather than non-porous surfaces. The more common of these developers use ferrous ions (from a ferrous/ferric redox couple) to reduce silver ions on the surface of latent print residue. Five such silver physical developers are compared through their cell potential ΔE (and the corresponding reaction quotient Q). Each developer is represented by a point on a line given by R = QC where R = [Fe3+]/[Fe2+] and C = [Ag+] and has a point on the line given by Req = QeqCeq where Qeq = K = 1.22 corresponds ΔE = 0. The quantity C - Ceq is the maximum amount of silver it can deposit. The development rate of a silver physical developer is directly related to its cell potential ΔE, the temperature, the maximum amount of silver that it can deposit, and the magnitude of [Fe2+]/[Ag+]. The contrast of a physically developed latent print (on light or dark surfaces) can be enhanced by optical, image enhancement, scanning electron, x-ray, and chemical methods. The latter includes bleaching or intensifying methods, fluorescent dye toning, and radioactive sulfur toning.
RESUMEN
An assembly that allows a pseudo real-time (one second delay) observation of latent fingerprints by their short ultraviolet luminescence was designed. It is composed of a mercury-xenon lamp and a CCD camera, both water-cooled and computer-controlled. The system is used to study the behaviour of latent fingerprints and stains of body fluids such as blood, semen and saliva under short-UV illumination.
Asunto(s)
Líquidos Corporales/química , Sistemas de Computación , Dermatoglifia/clasificación , Medicina Legal/métodos , Rayos Ultravioleta , Glándulas Ecrinas/metabolismo , Fluorescencia , Medicina Legal/instrumentación , Humanos , Mediciones LuminiscentesRESUMEN
Long term administration of 3'-azidothymidine (AZT) for the treatment of AIDS has led to detrimental clinical side effects in some patients, the biochemical causes of which are still being delineated. Base-substituted, azido-nucleotide photoaffinity analogs have routinely proven to be effective tools for identifying and characterizing nucleotide-utilizing enzymes. Therefore, we have synthesized 5-azido-3'-azido-2',3'-dideoxyuridine, which is a potential photoaffinity analog of two human immunodeficiency virus drugs, AZT and 3'azido-2',3'-dideoxyuridine. A partially purified herpes simplex virus type 1 thymidine kinase and [gamma-32P]ATP were used to make an AZT monophosphate analog, [32P]5-azido-3'-azido-2',3'-dideoxyuridine monophosphate. The photoaffinity properties of this analog were initially tested with herpes simplex virus type 1 thymidine kinase. Photoaffinity labeling of this enzyme was saturable (half-maximal, 30 microM) and could be specifically inhibited by AZT, AZT monophosphate, thymidine, and thymidine monophosphate. Photolabeling of rat liver microsomal membranes was also done, and several membrane proteins that interact with AZT monophosphate were identified. The antiviral and cytotoxic activities of 5-azido-3'-azido-2',3'-dideoxyuridine were determined using human immunodeficiency virus, type 1 strain IIIB and an AZT drug-resistant strain in human T lymphocyte H9 cells.
Asunto(s)
Marcadores de Afinidad/metabolismo , Antivirales/metabolismo , Herpesvirus Humano 1/enzimología , Timidina Quinasa/metabolismo , Zidovudina/análogos & derivados , Marcadores de Afinidad/farmacología , Animales , Antivirales/síntesis química , Antivirales/farmacología , VIH/efectos de los fármacos , Microsomas Hepáticos/metabolismo , Ratas , Zidovudina/metabolismo , Zidovudina/farmacologíaRESUMEN
Two methods are presented for the identification of ink, both of which are currently being used by laboratories involved in ink analysis. Both methods incorporate physical and chemical procedures. The differences are primarily in chemical methods involving spot tests and thin layer chromatographic (TLC) techniques. Furthermore, one method utilizes spectrophotometric scanning of the TLC plate whereas the other method utilizes solution spectrophotometry. It is recommended that both methods be evaluated by several laboratories.