RESUMO
One of the challenges for producing active chitinase formulations relies on the gap between the laboratory tests and the biological scenarios where the enzyme will perform its function. In this work, we have employed different Langmuir monolayer arrays to evaluate the interfacial behavior of a recently purified recombinant chitinase, Chi18-5. We have demonstrated that two conformations exist for the chitinase at pH values close to its pI, showing very distinct structural properties at the air/aqueous interface. Enzyme activity was assessed by implementing different kinetic approaches and using a chitosan-1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) mixed film as organized substrate model membrane. Combining these strategies, we demonstrated that better catalytic efficiencies can be obtained for Chi18-5 at pH 5. Moreover, the chitinase activity at the air/aqueous interface can be tuned by introducing in situ pH modifications over the surrounding milieu. We also studied the changes in the topography at the mesoscale level using Brewster Angle Microscopy (BAM). We found that Chi18-5 segregated onto the chitosan domains of the membrane, showing differences in homogeneity depending on the pH imposed. Alternatively, pure Chi18-5 was tested for immobilization onto a hydrophilic activated solid support using the Langmuir-Blodgett technique. Atomic Force Microscopy (AFM) analyses showed successfully stabilization and preservation of molecular features attributed to the pH at which the enzyme deposition was performed.
Assuntos
Quitosana , Microscopia de Força Atômica , Propriedades de SuperfícieRESUMO
A functional skeletal criterion, as an extension of the van der Klaauw's cranial theory, was adopted in the present study. The null hypothesis tested was: "The major skeletal components of the platyrrhine body grow linearly, regardless of their functional dependence to different demands." The acceptance of the hypothesis will imply that all Saimiri skeletal growth may be satisfactorily explained by independent variables in a single equation. The rejection will suggest that such skeletal growth patterns have to be explained by variables in several different equations, and perhaps these equations may vary with the effect of sex and undernutrition. Control and undernourished squirrel monkeys were radiographed monthly for 2 years; they were also measured; and their volumetric and morphometric neurocranial, facial, and pelvic indices were calculated. The curves that best described each of the 24-point sequences were obtained. Three main growth patterns were observed: 1) Simple linear (femur length for all groups, and pelvic index for control and undernourished females), for which the simple regression equation explained more than 95% of the variation; 2) Complex linear (pelvic index for control and undernourished males, and neurocranial and facial indices for all of the groups), for which more than 95% of the variation was explained by one of the four four-function type equations; and 3) Noncorrelated with age (neurofacial index for undernourished males, and pelviofemoral index for control females and undernourished males and females), which showed nonsignificant correlations with respect to age. The food intake and the oscillations of the environmental temperature might help to explain the undulating growth trajectory observed in the complex linear components.
Assuntos
Desenvolvimento Ósseo , Distúrbios Nutricionais/veterinária , Saimiri/crescimento & desenvolvimento , Animais , Feminino , Fêmur/crescimento & desenvolvimento , Estudos Longitudinais , Masculino , Modelos Teóricos , Pelve/crescimento & desenvolvimento , Saimiri/anatomia & histologia , Fatores SexuaisRESUMO
The environmental effect on growth and sexual dimorphism is mediated by endocrinological dysfunctions. It was shown that malnutrition acts on the hypotalamus-pituitary-glandular axis. An experiment was made in Wistar rats to determine the effect of some gonadic hormones on the functional components of the skull to which sex dimorphism was alterated by a postnatal undernutrition. The effects of these hormones in restoring sexual cranial dimorphism was tested. Four treatments were applied: control, with food intake ad-libitum; undernutrition (50% of the control food intake); undernutrition plus periodic injections of testosterone and estradiol to males and females, respectively and sham-operated animals, which were injected with oil vehicle only. A radiological longitudinal study was performed between 20 and 80 days of postnatal age. The length width and height of the neural and facial components were measured on each radiograph. Data were processed by ANOVA and Mann-Whitney statistical tests were performed by means of the SYSTAT 7.0 statistical package. Results showed that gonadic hormones restored the sexual cranial dimorphism by stimulating (testosterone) or suppressing (estradiol) the growth of the cranial components.
Assuntos
Estradiol/análogos & derivados , Distúrbios Nutricionais/complicações , Caracteres Sexuais , Testosterona/análogos & derivados , Análise de Variância , Animais , Estradiol/farmacologia , Feminino , Masculino , Radiografia , Ratos , Crânio/anatomia & histologia , Crânio/diagnóstico por imagem , Crânio/efeitos dos fármacos , Estatísticas não Paramétricas , Testosterona/farmacologia , Fatores de TempoRESUMO
Se presenta un neonato con atresias intestinales ubicadas en el píloro, yeyuno, íleon y colon respectivamente. En la primera operación se realizó una gastrostomía seguida de una piloroplastía instalando una sonda de Petzzer como gastrostomía y una sonda transpilórica. La atresia ileall fue resecada y se realizó una ileostomía. La atresia colónica múltiple obligó a una colectomía y se efectuó el cierre del rectosigma distal a lo Hartmann. Por persistir la oclusión intestinal alta se lo reoperó resecándose un diafragma yeyunal no detectado en la primera cirugía. Ante la persistencia de oclusión se efectuó una tercera operación enhebrándose todo el intestino desde la gastrostomía a la ileostomía, con una sonda de silicona multiperforada que fue mantenida por 7 días, permitiendo la progresiva alimentación enteral satisfactoria. El niño falleció en pleno período de recuperación por la aspiración de un vómito. En la atresia intestinal múltiple existiría un proceso inflamatorio que produce alteraciones estructurales en el intestino que llevan a su obstrucción, su etiología sería diferente a la atresia intestinal única cuyo origen es probablemente vascular...
Assuntos
Humanos , Recém-Nascido , Atresia Intestinal/cirurgiaRESUMO
Se presenta un neonato con atresias intestinales ubicadas en el píloro, yeyuno, íleon y colon respectivamente. En la primera operación se realizó una gastrostomía seguida de una piloroplastía instalando una sonda de Petzzer como gastrostomía y una sonda transpilórica. La atresia ileall fue resecada y se realizó una ileostomía. La atresia colónica múltiple obligó a una colectomía y se efectuó el cierre del rectosigma distal a lo Hartmann. Por persistir la oclusión intestinal alta se lo reoperó resecándose un diafragma yeyunal no detectado en la primera cirugía. Ante la persistencia de oclusión se efectuó una tercera operación enhebrándose todo el intestino desde la gastrostomía a la ileostomía, con una sonda de silicona multiperforada que fue mantenida por 7 días, permitiendo la progresiva alimentación enteral satisfactoria. El niño falleció en pleno período de recuperación por la aspiración de un vómito. En la atresia intestinal múltiple existiría un proceso inflamatorio que produce alteraciones estructurales en el intestino que llevan a su obstrucción, su etiología sería diferente a la atresia intestinal única cuyo origen es probablemente vascular...
Assuntos
Humanos , Recém-Nascido , Atresia Intestinal/cirurgiaRESUMO
A nine months old boy was admitted to the hospital with the diagnosis of meningoencephalitis 15 days after having a clinically diagnosed chickenpox. Lumbar puncture showed clear CSF with 0.23 g/l of proteins, 57 mg/dl of glucose, 30 red cells/mm3 and 5 leukocytes/mm3. Blood count showed a packed red cell volume of 22%, a hemoglobin of 7 g/dl, 14800 leukocytes with 1% eosinophils, 5% band and 39% segmented neutrophils, 50% lymphocytes and 5% monocytes and a decreased platelet count. On the fourth hospitalization day, the patient had vomiting, irritability and stiff neck. A new lumbar puncture showed a clear CSF that differed from the former only in the glucose level that increased to 102 mg/dl. The patient died and the necropsy showed a congestive and enlarged brain and congestive meninges infiltrated with lymphocytes. There was lymphoid follicle hyperplasia in the small bowel and enlarged mesenteric lymph nodes. Samples of brain, brain stem, spinal cord and stools were sent for virological study. A Coxsackie B-5 virus was isolated from the spinal cord sample.
Assuntos
Infecções por Coxsackievirus/diagnóstico , Enterovirus Humano B/isolamento & purificação , Meningoencefalite/virologia , Encéfalo/patologia , Infecções por Coxsackievirus/líquido cefalorraquidiano , Evolução Fatal , Humanos , Lactente , MasculinoRESUMO
Two cases of malignant vulvar tumors are presented: a malignant Melanoma and a case of Carcinoma of the Bartholin Gland. Both were diagnosticated during 1993 in the Obstetrics and Gynecology Department of Dr. Félix Bulnes Cerda Hospital. Clinical and anatomophatological aspects are studied.