RESUMO
A purpose-designed anthraquinone-horseradish peroxidase (HRP)-cell penetrating peptide hybrid 1 showed high and effective cell permeability. Furthermore, 1 exhibited enzymatic activity without photo-irradiation, whereas significant self-degradation and loss of enzymatic activity occurred upon photo-irradiation in living cells.
Assuntos
Antraquinonas/efeitos da radiação , Peptídeos Penetradores de Células/efeitos da radiação , Peroxidase do Rábano Silvestre/efeitos da radiação , 3,3'-Diaminobenzidina/química , Antraquinonas/síntese química , Antraquinonas/química , Antraquinonas/toxicidade , Armoracia/enzimologia , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Peptídeos Penetradores de Células/síntese química , Peptídeos Penetradores de Células/química , Peptídeos Penetradores de Células/toxicidade , Corantes/química , Desenho de Fármacos , Peroxidase do Rábano Silvestre/síntese química , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/toxicidade , Humanos , Indicadores e Reagentes/química , Raios UltravioletaRESUMO
Single whiskers are topographically represented in the trigeminal (V) nucleus principalis (PrV) by a set of cylindrical aggregates of primary afferent terminals and somata (barrelettes). This isomorphic pattern is transmitted to the thalamus and barrel cortex. However, it is not known if terminals in PrV from neighboring whiskers interdigitate so as to violate rules of spatial parcellation predicted by barrelette borders; nor is it known the extent to which higher order inputs are topographic. The existence of inter-whisker arbor overlap or diffuse higher order inputs would demand additional theoretical principles to account for single whisker dominance in PrV cell responses. In adult rats, first, primary afferent pairs responding to the same or neighboring whiskers and injected with Neurobiotin or horseradish peroxidase were rendered brown or black to color-code their terminal boutons. When collaterals from both fibers appeared in the same topographic plane through PrV, the percentage of the summed area of the two arbor envelopes that overlapped was computed. For same-whisker pairs, overlap was 5 ± 6% (mean ± SD). For within-row neighbors, overlap was 2 ± 5%. For between-row neighbors, overlap was 1 ± 4%. Second, the areas of whisker primary afferent arbors and their corresponding barrelettes in the PrV were compared. In the transverse plane, arbor envelopes significantly exceeded the areas of cytochrome oxidase-stained barrelettes; arbors often extended into neighboring barrelettes. Third, bulk tracing of the projections from the spinal V subnucleus interpolaris (SpVi) to the PrV revealed strict topography such that they connect same-whisker barrelettes in the SpVi and PrV. Thus, whisker primary afferents do not exclusively project to their corresponding PrV barrelette, whereas higher order SpVi inputs to the PrV are precisely topographic.
Assuntos
Rede Nervosa/fisiologia , Núcleos do Trigêmeo/fisiologia , Vibrissas/anatomia & histologia , Vibrissas/inervação , Vias Aferentes/fisiologia , Animais , Biotina/análogos & derivados , Biotina/metabolismo , Biotina/toxicidade , Mapeamento Encefálico , Dextranos/metabolismo , Feminino , Peroxidase do Rábano Silvestre/toxicidade , Masculino , Ratos , Ratos Sprague-Dawley , Tempo de Reação/fisiologia , Vibrissas/lesõesRESUMO
In our previous double-labeling studies, the fluorescent anatomical tracers Fluorogold (FG) and Texas red dextran amine (TRDA) were used to demonstrate that descending brain neurons, approximately 80% of which are reticulospinal (RS) neurons, in spinal cord-transected larval lamprey regenerate their axons. However, the numbers of FG-labeled descending brain neurons decreased significantly with increasing recovery times, from 2 to 16 weeks. For some FG-labeled mammalian neurons, FG appears to degrade and/or be lost over time, while in other neurons this tracer can kill neurons. In the present study, these possibilities were examined in larval lamprey for FG-labeled descending brain neurons. As in our previous studies, FG was applied to the spinal cord at 40% body length (BL, relative distance from the head) to retrogradely labeled descending brain neurons, and after recovery times of 2, 8, or 16 weeks, HRP, a non-toxic retrograde tracer, was applied to the spinal cord at 20% BL to determine if the numbers of HRP-labeled neurons were reduced. At these three recovery times, the numbers of HRP-labeled descending brain neurons were not significantly different than the numbers of HRP-labeled neurons in control animals that were not labeled with FG. Furthermore, the size and morphology of cell bodies and dendritic trees were not noticeably different in descending brain neurons with and without FG. Thus, in larval lamprey, FG does not appear to kill these neurons, but some FG probably is degraded and/or lost from neurons with increasing recovery times.
Assuntos
Tronco Encefálico/efeitos dos fármacos , Vias Eferentes/efeitos dos fármacos , Lampreias/metabolismo , Larva/metabolismo , Degeneração Neural/induzido quimicamente , Estilbamidinas/toxicidade , Animais , Tronco Encefálico/citologia , Tronco Encefálico/metabolismo , Contagem de Células , Morte Celular/efeitos dos fármacos , Morte Celular/fisiologia , Vias Eferentes/citologia , Vias Eferentes/metabolismo , Corantes Fluorescentes/metabolismo , Corantes Fluorescentes/toxicidade , Cones de Crescimento/efeitos dos fármacos , Cones de Crescimento/metabolismo , Peroxidase do Rábano Silvestre/metabolismo , Peroxidase do Rábano Silvestre/toxicidade , Lampreias/anatomia & histologia , Lampreias/crescimento & desenvolvimento , Larva/anatomia & histologia , Degeneração Neural/fisiopatologia , Regeneração Nervosa/fisiologia , Neurotoxinas/metabolismo , Neurotoxinas/toxicidade , Formação Reticular/citologia , Formação Reticular/efeitos dos fármacos , Formação Reticular/metabolismo , Traumatismos da Medula Espinal/fisiopatologia , Coloração e Rotulagem/métodos , Estilbamidinas/metabolismo , Fatores de TempoRESUMO
An enzyme-based iodine (EBI) disinfectant that continuously generates free molecular iodine in a controlled fashion was developed and evaluated for use in disinfecting flexible fibreoptic endoscopes (FFEs). EBI is a powder concentrate that produces iodine from sodium iodide and calcium peroxide when catalyzed by horseradish peroxidase. After dissolution in water, it delivers relatively high concentrations of free molecular iodine (> 15 ppm) at relatively low concentrations of total iodine (30-40 ppm). It demonstrates the ability to function as an effective low level iodine disinfectant by rapidly inactivating bacteria, fungi and viruses. A unique feature of the EBI system is the ability to reoxidize reduced iodine which results in a constant level of active (free molecular) iodine during use. EBI inactivates Mycobacterium bovis var BCG more rapidly than 2% glutaraldehyde (Cidex-7). Its sporicidal activity, however, was found to be slower than the aldehyde formulation. The qualification of EBI for use as a practical disinfectant was shown by its negligible toxicity in dermal, ocular, oral and inhalation studies on animals, which is attributed to the low level of total iodine in the solution.
Assuntos
Desinfetantes/farmacologia , Peroxidase do Rábano Silvestre/farmacologia , Iodo/farmacologia , Animais , Bactérias/efeitos dos fármacos , Desinfetantes/toxicidade , Combinação de Medicamentos , Endoscópios/microbiologia , Contaminação de Equipamentos/prevenção & controle , Fungos/efeitos dos fármacos , Cobaias , Peroxidase do Rábano Silvestre/toxicidade , Iodo/toxicidade , Dose Letal Mediana , Testes de Sensibilidade Microbiana/estatística & dados numéricos , Pós , Coelhos , Ratos , Esporos Bacterianos/efeitos dos fármacos , Fatores de Tempo , Vírus/efeitos dos fármacosRESUMO
After intratracheal or subcutaneous priming with horseradish peroxidase (HRP), no anti-HRP-forming cells were present in the bronchus-associated lymphoid tissue (BALT) or the lung of the rat. After intratracheal priming and intratracheal boosting with HRP no specific antibody-forming cells were observed either in the BALT or the lung. A few blast cells containing anti-HRP antibody were found in paratracheal lymph nodes, which is possibly the source of anti-HRP-forming cells. After subcutaneous priming in the hind footpad and intratracheal boosting specific antibody-forming cells were present in both the BALT and in the lung. In the BALT these cells were found peripherally, and in the lung perivascularly and peribronchiolarly. The simultaneous appearance of these anti-HRP-forming cells at both sites, their localization and their morphology strongly indicate that they are recruited from the circulation and not formed in situ; the probable source is the popliteal lymph node.
Assuntos
Células Produtoras de Anticorpos/imunologia , Brônquios/patologia , Peroxidase do Rábano Silvestre/toxicidade , Pulmão/patologia , Peroxidases/toxicidade , Animais , Brônquios/efeitos dos fármacos , Brônquios/imunologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Masculino , Ratos , Ratos EndogâmicosRESUMO
The possible neurotoxic effects of five commonly used steroid agents were examined. Using histologic studies and studies of the microneural circulation, it was found the steroids can indeed cause neurotoxicity. The injection site was critical in effecting injury. Only intrafascicular injection caused damage. The damage produced varied with the agent used. Dexamethasone (Decadron) caused minimal damage, while hydrocortisone (Solu-Cortef) and triamcinolone hexacetonide (Aristospan) caused widespread axonal and myelin degeneration. Disturbance in the blood-nerve barrier correlated with the changes noted on light and electron microscopy, but is thought to be coincidentally and not causally related. In conclusion, it was shown that the intrafascicular injection of commonly used steroid agents had a direct toxic effect on peripheral nerve-fibers and caused a disruption of the blood-nerve barrier. Use of the more toxic agents in the vicinity of peripheral nerves should probably be avoided.
Assuntos
Nervos Periféricos/efeitos dos fármacos , Esteroides/toxicidade , Animais , Dexametasona/toxicidade , Peroxidase do Rábano Silvestre/toxicidade , Hidrocortisona/toxicidade , Injeções , Masculino , Metilprednisolona/toxicidade , Ratos , Ratos Endogâmicos , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/patologia , Esteroides/administração & dosagem , Triancinolona Acetonida/análogos & derivados , Triancinolona Acetonida/toxicidadeRESUMO
When guinea pig cochlea was perfused in vivo with a solution of 1% horseradish peroxidase (HRP) in artificial perilymph, the enzyme was found in the basilar membrane, spiral limbus, some outer and inner hair cells and some supporting cells and it was gradually cleared away with time. Acute signs of cell damage included swelling, vacuolization and diffuse labeling of some hair cells, but stereocilia remained normal in configuration. Albino melanocytes of the spiral ligament were also damaged, and vacuolization of Reissner's membrane occurred after 10% HRP. Both concentrations caused a gradual decline in CM, showing that HRP is acutely ototoxic but its mode of action is unknown. No retrograde transport of HRP to spiral ganglion cells or to brain stem neurons occurred, but some brain stem neurons took up HRP from the neuropil following diffusion from the cochlea.