Surface characterization and interfacial activity of chitinase chi18-5 against chitosan in langmuir monolayers.

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.

Alemtuzumab induction with tacrolimus monotherapy in de novo renal transplantation.

OBJECTIVES: Alemtuzumab is increasingly being used as induction therapy for kidney transplantation, allowing immunosuppression minimization. This study examined the efficacy of alemtuzumab induction followed by low-dose tacrolimus monotherapy in standard risk primary kidney transplant patients. METHODS: This retrospective cohort of primary standard risk renal transplant recipients were given alemtuzumab induction and low-dose tacrolimus maintenance immunosuppression (target trough 7 to 10 ng/mL for the first 6 months and 5 to 7 ng/mL thereafter). Serum creatinine values, acute rejection episodes, and graft survival were noted at week 1 as well as months 3, 6, 12, and 18. RESULTS: At the time of analysis, 47 patients were at 6 months, 28 at 12 months, and 6 patients at 18 months from transplant. Mean follow-up was 12.53 months (range, 6 to 23). Mean serum creatinine was 1.47 +/- 0.65 mg/dL at 3 months, 1.56 +/- 0.84 at 6 months, 1.45 +/- 0.37 at 12 months, and 1.74 +/- 0.35 at 18 months. The 1-year clinical acute rejection rate was 21% (6/28), occurring at 0 to 3 months in 2 (33%), 4 to 6 months in 1 (17%), and >6 months in 3 patients (50%). Biopsy-proven acute rejection was 14% (4/28). The episodes were classified as borderline in one, Banff 2A in two, and Banff 3 in one patients. One patient had both acute cellular and acute humoral rejection; half responded to steroid pulse therapy. The 1-year patient survival rate was 90%. The 1-year death-censored graft survival rate was 98%. CONCLUSION: Alemtuzumab induction with tacrolimus monotherapy is an acceptable option in standard risk patients. BPAR was 14%, but renal function remained satisfactory at 18 months posttransplant.

Detection of cytomegalovirus in the meconium of infected newborns by polymerase chain reaction.

OBJECTIVE: Congenital cytomegalovirus (CMV) infection is a leading cause of hearing loss and mental retardation throughout the world. Detection of the CMV DNA by polymerase chain reaction (PCR) offers a sensitive, rapid, and specific means of identification. Meconium, the stool formed in utero, may be an ideal specimen for CMV detection. The objective of this study was to develop a PCR-based methodology for the detection of CMV in the meconium of neonates. METHODS: Meconium was collected from 10 newborn infants (seven with positive viral cultures and three uninfected infants born to CMV-seropositive mothers). For each, DNA was isolated from meconium by organic extraction and attachment to a DNA-binding matrix, and PCR was performed using amplimers specific for the major intermediate early (MIE) and late antigenic (LA) regions of CMV. RESULTS: Gel electrophoresis demonstrated an anticipated PCR product of 250 base pairs (bp) corresponding to the MIE region of CMV in all infected and positive control meconium samples. Furthermore, a single band of 150 bp corresponding to the LA region of CMV was also amplified in several of the infected infants. Conversely, no amplification of these antigenic regions was noted in either uninfected infants born to CMV-seropositive mothers or negative controls. CONCLUSIONS: CMV is present within the meconium of infected neonates and is readily detectable by PCR.

Growth of skeletal components in the young squirrel monkey (Saimiri sciureus boliviensis): a longitudinal experiment.

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.

[Effect of gonadal hormones on sexual dimorphism in malnutrition substrates]. / Efecto de las hormonas gonadales sobre el dimorfismo sexual en substrato de desnutrición.

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.

Decreased gene expression of endothelial nitric oxide synthase in newborns with persistent pulmonary hypertension.

Previous studies in adults have shown that chronic pulmonary hypertension is associated with decreased endothelial nitric oxide synthase (eNOS) expression in pulmonary arteries. However, the role of decreased eNOS expression in persistent pulmonary hypertension of the newborn (PPHN) is unknown. We investigated the hypothesis that umbilical vein endothelial cells cultured from infants with PPHN will have decreased eNOS expression. Umbilical cords were collected from meconium-stained infants at birth, and endothelial cells were isolated if the infants developed PPHN. Endothelial cells were grown in primary culture, and total RNA was isolated. cDNA was reverse transcribed from mRNA and amplified by PCR. An expected product of approximately 550 bp was found in all control infants but only in two of the six infants with PPHN. Identity of the PCR product was confirmed by Southern hybridization to a separate internal eNOS-specific probe. Amplification of beta-actin cDNA, an internal control, was detected in all controls and in all infants with PPHN, including the four infants without the eNOS band. There was no difference in the course and outcome of patients with presence or absence of the eNOS band. However, there was an acidotic arterial blood pH (7.19-7.29) and intrapartum fetal heart rate decelerations in all four infants without eNOS expression. In conclusion, eNOS mRNA was detected in all normal term infants but was notably absent in the majority of infants with PPHN in this pilot study. The development of PPHN is multifactorial, and a decrease in eNOS gene expression may occur in some infants. Whether the decreased eNOS transcript is a cause of PPHN or a result of intrapartum stress remains to be determined.

Atresia intestinal múltiple: manejo quirúrgico / Surgical Management of multiple intestina atresias

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...

Atresia intestinal múltiple: manejo quirúrgico / Surgical Management of multiple intestina atresias

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...

[Isolation of Coxsackieviruses B5 in a fatal case of meningoencephalitis]. / Aislamiento de virus Coxsackie B-5 en un caso fatal de meningoencefalitis.

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.

[2 infrequent vulvar tumors]. / Dos tumores vulvares poco frecuentes.

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.

The control of glycogen metabolism in yeast. 1. Interconversion in vivo of glycogen synthase and glycogen phosphorylase induced by glucose, a nitrogen source or uncouplers.

The addition of glucose to a suspension of yeast initiated glycogen synthesis and ethanol formation. Other effects of the glucose addition were a transient rise in the concentration of cyclic AMP and a more prolonged increase in the concentration of hexose 6-monophosphate and of fructose 2,6-bisphosphate. The activity of glycogen synthase increased about 4-fold and that of glycogen phosphorylase decreased 3-5-fold. These changes could be reversed by the removal of glucose from the medium and induced again by a new addition of the sugar. These effects of glucose were also obtained with glucose derivatives known to form the corresponding 6-phosphoester. Similar changes in glycogen synthase and glycogen phosphorylase activity were induced by glucose in a thermosensitive mutant deficient in adenylate cyclase (cdc35) when incubated at the permissive temperature of 26 degrees C, but were much more pronounced at the nonpermissive temperature of 35 degrees C. Under the latter condition, glycogen synthase was nearly fully activated and glycogen phosphorylase fully inactivated. Such large effects of glucose were, however, not seen in another adenylate-cyclase-deficient mutant (cyr1), able to incorporate exogenous cyclic AMP. When a nitrogen source or uncouplers were added to the incubation medium after glucose, they had effects on glycogen metabolism and on the activity of glycogen synthase and glycogen phosphorylase which were directly opposite to those of glucose. By contrast, like glucose, these agents also caused, under most experimental conditions, a detectable rise in cyclic AMP concentration and a series of cyclic-AMP-dependent effects such as an activation of phosphofructokinase 2 and of trehalase and an increase in the concentration of fructose 2,6-bisphosphate and in the rate of glycolysis. Under all experimental conditions, the rate of glycolysis was proportional to the concentration of fructose 2,6-bisphosphate. Uncouplers, but not a nitrogen source, also induced an activation of glycogen phosphorylase and an inactivation of glycogen synthase when added to the cdc35 mutant incubated at the restrictive temperature of 35 degrees C without affecting cyclic AMP concentration.