Experience in geriatric patients at the Gastrointestinal Surgery Department of the Hospital Español, Mexico, 2013-2019. Five-year experience in GI surgery in geriatric patients.

INTRODUCTION: The aging of the population is one of the most widely studied and impactful social phenomena of this century. Up to 25% of all emergency hospital admissions can be due to diseases that require general surgery. AIMS: To describe the experience at the Department of Gastrointestinal Surgery of the Hospital Español, Mexico, in patients above 65 years of age. MATERIALS AND METHODS: A retrospective, observational, analytic, and cross-sectional study was conducted that included 595 medical records of geriatric patients that underwent surgical procedures, within the time frame of November 2013 and February 2019. RESULTS: A total of 52% (309) of the patients were men and 48% (286) were women. Mean patient age was 75.38 years, with a mode of 73 years, and a maximum age of 100 years. Mean hospital stay was 4.5 days. Postoperative complications presented in 12.77% of the patients, 3.02% of which were severe. Reoperation was required in 13 patients (0.02%). The perioperative mortality rate was 2.02%. CONCLUSIONS: The morbidity and mortality rates of the procedures that corresponded to general surgery in our case series were similar to those reported in the literature. A statistically significant number of patients underwent laparoscopic surgery, within the study period.

Lactose drives Enterococcus expansion to promote graft-versus-host disease.

Disruption of intestinal microbial communities appears to underlie many human illnesses, but the mechanisms that promote this dysbiosis and its adverse consequences are poorly understood. In patients who received allogeneic hematopoietic cell transplantation (allo-HCT), we describe a high incidence of enterococcal expansion, which was associated with graft-versus-host disease (GVHD) and mortality. We found that Enterococcus also expands in the mouse gastrointestinal tract after allo-HCT and exacerbates disease severity in gnotobiotic models. Enterococcus growth is dependent on the disaccharide lactose, and dietary lactose depletion attenuates Enterococcus outgrowth and reduces the severity of GVHD in mice. Allo-HCT patients carrying lactose-nonabsorber genotypes showed compromised clearance of postantibiotic Enterococcus domination. We report lactose as a common nutrient that drives expansion of a commensal bacterium that exacerbates an intestinal and systemic inflammatory disease.

Manejo de la depresión en fase de remisión en Atención Primaria / Management of depression in remissionphase in Primary Care

OBJETIVO. La depresión es el problema de salud mental más frecuente en Atención Primaria (AP). Su manejo terapéutico puede ser diferente en AP al del ámbito especialista, sobre todo durante la fase de estabilización. El objetivo del presente estudio fue conocer la actitud del médico de AP frente al paciente depresivo en remisión y evaluar si la resolución total del cuadro es un objetivo factible en este ámbito. MÉTODOS. 1.a parte: encuesta a médicos de AP sobre su experiencia en el manejo de la depresión en remisión. 2.a parte: estudio transversal, multicéntrico, donde se recogieron datos clínicos de pacientes con depresión en fase de remisión, según criterio clínico. Cada médico debía recoger datos de 5 pacientes, de forma consecutiva, durante 3 meses. Se evaluó la proporción de pacientes con remisión total según escala HDRS, versión reducida de 6 ítems (remisión total: HDRS-6 ≤5), y los factores relacionados con un peor estado clínico mediante un test de regresión lineal. RESULTADOS. 1.a parte: la mayoría de entrevistados coincidía en la necesidad de un tratamiento prolongado (entre 6 meses y 1 año), con el mismo fármaco y dosis a las que respondió el paciente. La baja adherencia fue referida como el principal problema de esta etapa. 2.a parte: el 37% de pacientes reunían criterios de remisión total. Edad, ocupación, tiempo de evolución, comorbilidad psiquiátrica, antecedentes depresivos o satisfacción al tratamiento se relacionaron con un peor estado clínico. CONCLUSIONES. El manejo clínico de la depresión en fase de remisión en AP coincide con las guías terapéuticas vigentes. La proporción de pacientes con remisión total fue similar a la observada en otros ámbitos clínicos

OBJECTIVE. Depression is the most common problem of psychiatric disorders encountered in Primary Care. Its management can differ from the psychiatrist's management, mainly during the remission phase. This study aimed to explore attitudes on management of depressed patients in remission in Primary Care and evaluate whether full remission is a feasible objective in this setting. METHODS. Part 1: semi-structured interview to Primary Care physicians on the management of depression in remission. Part 2: cross-sectional, multicenter study. Clinical data from depressed patients in remission (according to physician's criterion) were collected. Each physician should collect data on 5 consecutive patients seen over 3 months. The percentage of patients with full remission was evaluated by the Hamilton Depression Rating scale (6 items-short version) (full remission: HDRS-6 ≤5). Factors related with a worst clinical condition were evaluated by a lineal regression test. RESULTS. Part 1: most of the physicians agreed with the requirement to continue full-dose maintenance therapy for 6 to 12 months. Low adherence to treatment was reported as the main problem in this period. Part 2: 37% of patients met the full-remission criteria. Age, occupation, episode duration, psychiatric comorbidity, psychiatric antecedents, and treatment satisfaction were related with worst clinical condition. CONCLUSIONS. The long-term management of depression in Primary Care agrees with the current treatment guidelines. The percentage of patients fulfilling remission criteria was similar to the reports in other clinical settings

Propuesta para un registro clínico de demencias / A proposal for a clinical registry of dementias

Objetivo. Se presenta una propuesta de las característicasestructurales y funcionales necesarias para desarrollar un registrode demencias que permita recoger con garantías de fiabilidady validez la información estandarizada de los casos diagnosticadosde demencia en los centros sanitarios de atención especializada deun área geográfica definida. Desarrollo. Debido a la falta de informaciónsobre los aspectos relativos al impacto de las demenciassobre el sistema sanitario, en términos de utilización de recursos yen patrones de detección, derivación, diagnóstico y tratamiento enla práctica clínica habitual por parte de atención primaria y secundaria,se propone una implementación secuencial del registro paraadaptarse a cada territorio o región sanitaria. En primer lugar, sedeberían identificar los casos y las fuentes de información; en segundolugar, desarrollar un sistema de recogida de datos que permitaadoptar de forma estandarizada la recogida de información yestablecer una estrecha colaboración con los especialistas que llevena cabo el diagnóstico de demencia; y, en tercer lugar, aportar alregistro una estructura logística y de personal que centralice todaslas funciones y actividades del registro. Conclusiones. La vigilanciaepidemiológica es un instrumento fundamental para la planificación,gestión y distribución de los recursos sociosanitarios, para elseguimiento de la evolución natural de enfermedades crónicas asícomo para evaluar el impacto de programas preventivos. En estesentido, y desde un punto de vista funcional, la propuesta de unregistro de demencias cumple todos los requisitos básicos de la vigilanciaepidemiológica

Aims. We outline a proposal for the structural and functional features needed to develop a registry of dementiaswhich can be used to collect standardised information that is both reliable and valid concerning cases of dementia in thespecialised health care centres within a particular geographical area. Development. Due to the shortage of information aboutaspects concerning the impact of dementias on the health care system (in terms of the usage of resources and patterns ofdetection, referral, diagnosis and treatment in usual clinical practice in primary and secondary care), a sequentialimplementation of the registry is proposed so that it can be adapted to each health district or region. The first step is to identifythe cases and sources of information; second, a system for collecting data must be developed that allows information to begathered in a standardised manner while at the same time making it possible to work in close collaboration with thespecialists who diagnose dementia; and, third, it must be set up with the logistics and staff needed to centralise all thefunctions and activities of the registry. Conclusions. Epidemiological surveillance is an essential instrument for planning,managing and distributing community health resources, for following up the natural history of chronic diseases and forassessing the impact of programmes of prevention. In this respect, and from a functional point of view, the proposed registry ofdementias meets all the basic requirements of epidemiological surveillance

[A proposal for a clinical registry of dementias]. / Propuesta para un registro clinico de demencias.

AIMS: We outline a proposal for the structural and functional features needed to develop a registry of dementias which can be used to collect standardised information that is both reliable and valid concerning cases of dementia in the specialised health care centres within a particular geographical area. DEVELOPMENT: Due to the shortage of information about aspects concerning the impact of dementias on the health care system (in terms of the usage of resources and patterns of detection, referral, diagnosis and treatment in usual clinical practice in primary and secondary care), a sequential implementation of the registry is proposed so that it can be adapted to each health district or region. The first step is to identify the cases and sources of information; second, a system for collecting data must be developed that allows information to be gathered in a standardised manner while at the same time making it possible to work in close collaboration with the specialists who diagnose dementia; and, third, it must be set up with the logistics and staff needed to centralise all the functions and activities of the registry. CONCLUSIONS: Epidemiological surveillance is an essential instrument for planning, managing and distributing community health resources, for following up the natural history of chronic diseases and for assessing the impact of programmes of prevention. In this respect, and from a functional point of view, the proposed registry of dementias meets all the basic requirements of epidemiological surveillance.

Ectopic growth hormone-releasing hormone secretion by thymic carcinoid tumour.

The case of a 33-year-old-woman with Multiple Endocrine Neoplasia Type 1 (MEN1) syndrome and acromegaly due to ectopic growth hormone-releasing hormone (GHRH) secretion by a thymic carcinoid tumour is reported. Immunohistochemistry revealed positive immunoreactivity for GHRH, vasoactive intestinal polypeptide, somatostatin and alpha-subunit in the tumour cells. A previously undescribed new germ line mutation of the MEN1 protein gene was revealed.

Comparative study of human papillomavirus DNA infection detected in cervical lavage and brushing specimens by polymerase chain reaction

El papilomavirus humano (PVH es considerado uno de los principales factores involucrados en la génesis del cáncer del cuello uterino. El ADN del PVH se detectó empleando la reacción en cadena de la polimerasa (RCP) en 53 mujeres con citología previa de lesión escamosa intraepitelial de bajo grado (LEI) en célula cérvicovaginales obtenidas empleando el lavado cérvicovaginal y el escobillo cervical. En 35 mujeres (66.0 por ciento) los resultados fueron positivos con el método de lavado cervicovaginal, de las cuales sólo 18 de ellas fueron también positivas en las muestras obtenidas con escobillado. Ninguna de las mujeres tuvo ADN del PVH detectado en el escobillado sin haber sido detectado en el lavado cérvicovaginal. En el lavado encontramos 12 infecciones simples y 23 múltiples y en el escobillado detectamos 7 y 8 infecciones simples y múltiples respectivamente. El tipo viral mas frecuente en las muestras del lavado fue el PVH-18 (57.1 por ciento), y en las de escobillado el PVH-16 (93.3 por ciento). Comparando los resultados del lavado y escobillado ADN/PVH positivo con el diagnóstico citológico observamos mayor positividad con el método de lavado, así mismo con algunos factores epidemiológicos como la edad de inicio de la actividad sexual, poliandria y paridad se detectó también mayor positividad en las muestras de lavado. Concluimos que el lavado cérvicovaginal es un buen método de colección de células para detectar ADN del PVH en mujeres aparentemente sanas y para minimizar el sesgo en los estudio clínicos con el diagnóstico molecular.

Gastric myoelectrical activity in healthy children and children with functional dyspepsia.

The aim of this study was to investigate abnormalities in pediatric patients with functional dyspepsia. Fifteen symptomatic pediatric patients diagnosed with functional dyspepsia and 17 aged-matched healthy controls were studied. Gastric myoelectrical activity was recorded using surface electrogastrography for 1 hr in the fasting state and 1 hr after a test meal. It was found that, in comparison with the controls, the children with functional dyspepsia had a lower percentage of 2- to 4-cpm slow waves in both fasting state (66.0+/-4.7% vs 79.7+/-3.1%, P < 0.07) and fed state (72.4+/-5.4% vs 85.0+/-2.9%, P < 0.04), and a significantly higher instability of the dominant frequency in both fasting state (0.50+/-0.05 vs 0.31+/-0.04, P < 0.01) and fed state (0.39+/-0.05 vs 0.25+/-0.03, P < 0.05). It was also found the postprandial increase in EGG dominant power in the patients was inversely correlated with the total symptom score (r = 0.63, P = 0.03). It was concluded that abnormal gastric myoelectrical activity may play a role in the pathogenesis of pediatric functional dyspepsia.

Estudio citogenetico simultaneo en cáncer de cuello uterino y en linfocitos de sangre periferica / I study simultaneous citogenetico in cancer of uterine neck and in linfocitos of outlying blood

Los estudios citogenéticos y genéticos moleculares han confirmado que en el desarrollo y la progresión de las neoplasias malignas están involucrados cambios del material genético. En el cáncer de cuello uterino se han descrito aberraciones en los cromosomas; en la literatura hay algunos reportes de alteraciones cromosómicas en el cariotopo de los linfocitos perifericos en pacientes con cáncer. El objetivo del presente trabajo fue estudiar simultaneamente el cariotipo de las células tumorales y linfocitos de sangre periférica en las pacientes con cáncer de cuello uterino. Se estudiarón 68 pacientes atendidas en el Departamento de Detección y diagnóstico del Instituto de Enfermedades Neoplásicas, desde mayo de 1993 hasta agosto de 1997. El estudio citogenético se efectuó de acuerdo a la metodología de Verma y Babu. Las alteraciones más frecuentes fueron a) estructurales a nivel del cromosoma 1 en el 36.76 por ciento y del cromosoma 3 en el 20.58 por ciento y b)numéricas mayores de 46 cromosomas (25 por ciento) y menores de 46 cromosomas (30.88 por ciento). Se observaron otras alteraciones como trisomía 19, monosomía del gonosoma X y dobles minutos. El cariotipo de los linfocitos de la sangre periférica fue normal en número, en estructura y distribución. Se hace hincapié en el hallazgo de que los 4 casos estudiados de adenocarcinoma tenían un número menor de 46 cromosomas en el cariotipo tumoral y se sugiere el estduio de una casuística mayor para ver si esta es una característica de este tipo tumoral. Se concluye que las alteraciones encontradas están de acuerdo en mucho a lo que ha sido descrito en la literatura y que debe estudiar un número mayor de casos tratando de correlacionar las alteraciones cromosómicas con la respuesta al tratamiento y el pronóstico igualmente si algunas alteraciones tienen correlación con el grado histólogico del tumor, y si los mismos cambios se ven tanto en las lesiones precursoras como en enfermedad avanzaa. También se sugiere estudiar el cariotipo de los linfocitos de la sangre de pacientes con alto riesgo de desarrollar cáncer y en pacientes con neoplasias múltiples.

[Spanish version of ECBI (Eyberg Child Behavior Inventory): measurement of validity]. / Versión española del ECBI (Eyberg Child Behavior Inventory): medida de validez.

OBJECTIVES: To translate into Castilian (Spanish) and measure the validity of the ECBI (Eyberg Child Behaviour Inventory), a questionnaire to screen behavioural disorders in pre-school children. DESIGN: Translation and back-translation of the ECBI. A descriptive crossover study. SETTING: Primary Care Paediatrics. PATIENTS: All the 3, 4 and 5-year olds from 4 paediatric clinics at 4 Health Centres (n = 527). One refusal. MEASUREMENTS AND MAIN RESULTS: The questionnaire was filled in by the children's mothers and was repeated 20 days afterwards for 35 children. High coefficients of internal consistency (Cronbach's alpha = 0.87) and stability (intragroup correlation = 0.89 [0.78-0.94]) were obtained. There was good factorial validity, as 84% of the variance was explained by the four factors with value greater than 1. CONCLUSIONS: The Spanish version of the ECBI is a brief and easy questionnaire with good results in psychometric assessment. Therefore, it can be recommended for use in paediatric Primary Care in order to detect children with behavioural problems.

Patterns of gastric myoelectrical activity in human subjects of different ages.

The aim of this study was to investigate the developmental change of gastric myoelectrical activity in humans. Five groups of healthy subjects were studied, including 10 preterm newborns, 8 full-term newborns, 8 full-term infants (ages 2-6 mo), 9 children (ages 4-11 yr), and 9 adults. Gastric myoelectrical activity was recorded using surface electrogastrography for 30 min before and 30 min after a test meal in each subject. Spectral analysis methods were applied to compute the parameters of the electrogastrogram (EGG). The results showed that the percentage of 2- to-4-cycles/min (cpm) slow waves was 26.6 +/- 3.9% in the preterm newborns, 30.0 +/- 4.0% in full-term newborns, 70 +/- 6.1% in 2- to 6-mo-old infants (P < 0.001 compared with newborns), 84.6 +/- 3.2% in 4- to 11-yr-old children (P < 0.03 compared with infants), and 88.9 +/- 2.2% in the adults (P > 0.05 compared with children). In conclusion, gastric slow waves are absent at birth, and there is a maturing process after birth. Age-matched controls are necessary for the interpretation of EGG data from neonates and infants, whereas EGG data in children are the same as in adults.

Living related liver transplantation in Oklahoma.

Living related liver transplantation (LRLT) presents several advantages as compared to cadaveric liver transplantation, and it has become an increasingly popular option for children with end-stage liver diseases. Since 1995, five LRLT procedures have been performed at the authors' facility. Recipients were three boys and two girls, whose mean age was 2.6 years. Recipients' primary diagnoses were primary hyperoxaluria (PH) (n = 3), Alagille's syndrome (n = 1), and Byler's disease (n = 1). Left lateral segments harvested from their parents were used as the liver grafts on all patients. The donors included three mothers and two fathers, with a mean age of 29 years. Tacrolimus with steroids was used as immunosuppressive therapy. In all cases (mean follow-up time of 11 months), graft function was excellent and four children are doing very well. One boy died of post-transplant lymphoproliferative disorder (PTLD) 7 months after LRLT. All donors are doing very well with no postoperative complications. The authors believe that LRLT is a safe procedure for both the donor and the recipient, and provides, in children, an excellent alternative to cadaveric liver transplantation.

Algunos aspectos epidemiológicos-clínicos de la infección por PVH del cuello uterino confirmado histológicamente / Some clinical epidemiologic aspect of infection for HPV of the uterine cervix histologicall confirmed

Las fichas clínicas de 142 mujeres con infección cervical subclínica por PVH de cuello uterino, confirmadas histológicamente, que acudieron al Departamento de Detección y Diagnóstico del INEN, desde enero de 1991 a diciembre de 1993, fueron revisadas, para estudiar algunos aspectos clínico-epidemiológicos. El promedio de edad fue 35.8 años con un rango más frecuente de 20 a 49 años. La proporción de procedencia de mujeres de los diferentes distritos de Lima fue similar. El 1.6 por ciento era analfabeta. La unión conyugal se halló en el 85.9 por ciento. El 63.1 por ciento tuvo su primera relación sexual antes de los 20 años. casi la totalidad de mujeres no usó método de barrera. La localización anatómica más frecuente fue el labio anterior. El epitelio blanco característico de PVH fue la imagen colposcópica más frecuente. Este grupo de mujeres será considerada una cohorte y es importante el estudio de ADN y la tipificación del PVH para confirmar o rechazar la infección subclínica por PVH de cuello uterino. Este ha sido uno de los motivos para realizar un Protocolo de Investigación de la infección por PVH de cuello uterino mediante el estudio molecular de ADN que se está desarrollando en este departamento

Cáncer de cuello uterino: Rol de los factores masculino y femenino como riesgo: Estudio de casos y controles / Cervical cancer: risk factors

El cáncer de cuello uterino es la neoplasia más frecuente en la mujer peruana y representa uno de los principales problemas de salud pública en nuestro medio. La causa del cáncer de cuello uterino es considerada multifactorial, siendo la edad temprana de la primera relación sexual y la poliandria, reportadas como los factores de riesgo más importantes. Entre enero de 1988 y julio de 1990 en el Departamento de Detección y Diagnóstico, del Instituto Nacional de Enfermedades Neoplásicas se diseñó un estudio de casos y controles, con la finalidad de determinar el perfil del riesgo de cáncer de cuello uterino de la mujer peruana. Se estudió 644 personas: 161 parejas casos y 161 parejas controles, con la finalidad de evaluar los factores de riesgo de cáncer de cuello uterino, analizándose edad, vida sexual, alimentación, higiene sexual, hábitos, uso de anticonceptivos, antecedentes de Papanicolau y enfermedades venéreas previas, entre otros factores. Los datos se analizaron usando un modelo de "regresión logística multivariante" para un estudio de caso-control. Al inicio del análisis hubieron 27 variables para los hombres y 17 para las mujeres, habiéndose reducido el número de ellas -sin perder información- al emplearse un análisis de "componentes principales". "La regresión logística multivariante" estableció que los factores de riesgo más importantes fueron: abortos antes del primer parto (APP), número de gestaciones (NGES), edad de la primera relación sexual de la mujer (EPRS), uso del preservativo por parte del hombre (PRESERV), edad de la menarquia (MENR) y número de abortos (ABORT). Para estos factores se obtuvieron los ODDS RATIOS siguientes: a) No uso de preservativo. OR:4.938 (IC 95 por ciento, 1.82-13.39); b) APP,OR: 2.815 (IC 95 por ciento, 1.25-6.29); c) EPRS, OR:2.483 (IC 95 por ciento, 1.564-3.94) y NGES. OR, 1.945 (IC 95 por ciento, 1.20-3.13). Los resultados del presente estudio sugieren que el cáncer de cuello uterino puede ser una enfermedad de transmisión sexual

Chronic diarrhea and soy formulas. Inhibition of diarrhea by lactose.

Soy protein formulas are often poorly tolerated by infants with chronic nonspecific or postinfectious diarrhea syndrome. We found that these adverse responses may be prevented by using lactose, instead of sucrose or dextrimaltose, in soy formula. We studied 40 infants diagnosed as soy intolerant. They were given soy formula with differing carbohydrate contents in a randomized, blinded prospective study. Stool output, stool sodium content, and symptoms were significantly improved in infants receiving a soy-lactose formula; no difference was seen in formulas with sucrose or maltose. Improvement occurred in three to five days in most infants. Furthermore, the characteristic frequency distribution of the favorable response to lactose suggested a specific mechanism for the inhibition of water and electrolyte losses through the bowel. The results indicate that, in the absence of lactose intolerance, a soy-lactose formula could be useful in treating chronic diarrhea and secondary protein intolerance.

Maturational changes in terminal glycosylation of small intestinal microvillar proteins in the rat.

Studies were performed to identify rat intestinal microvillar proteins which undergo changes in terminal glycosylation during postnatal development. Pulse-labeling with [3H]fucose or N-[3H]acetylgalactosamine showed significantly higher incorporation into purified microvillar membranes of weanling than suckling rats. In contrast, the incorporation of [3H]sialic acid after pulse-labeling with N-[3H]acetylmanosamine was higher in suckling rats. SDS-polyacrylamide gel electrophoresis revealed these developmental differences in radioactive sugar incorporation to involve mainly proteins above Mr 90,000. 125I-labeled peanut lectin autoradiography revealed an Mr greater than 330,000 binding protein in suckling rats. Neuraminidase treatment of the membranes revealed the presence of sialyl-substituted sites in this protein in suckling, weaning and weanling animals, but the unmasking of sites decreased with advancing maturation. 125I-labeled Ulex europeus I autoradiography showed marked increases in binding of this lectin to Mr 66,000, 92,000, 130,000, 150,000 and greater than 330,000 proteins from weaning to weanling periods. Similar age-related increases in soybean lectin binding to Mr 130,000-150,000, and greater than 330,000 proteins were demonstrated by affinity chromatography. The Mr values of the major lectin-binding proteins were close to those reported for several hydrolases (trehalase, alkaline phosphatase, sucrase-isomaltase and glucoamylase). Comparison of the Coomassie blue-stained electrophoretograms from each age-group against the corresponding autoradiograms of lection-binding proteins led us to conclude that, while the content of these proteins in the membrane achieve their mature levels at or before weaning, their terminal glycosylation (desialylation, fucosylation, N-acetylgalactosamination) is not fully established until later development.

Effect of hormone administration on the sialylation and fucosylation of intestinal microvillus membranes of suckling rats.

Cortisone, thyroxine, epidermal growth factor, or insulin were administered to 8-day-old rats for 4 days. In comparison to saline-injected controls, cortisone treatment: 1) lowered the sialic acid and raised the fucose content of the intestinal microvillus membranes, 2) increased [3H]fucose incorporation into these membranes, and 3) decreased the membrane binding of 125I-wheat germ agglutinin, while increasing the binding of 125I-ulex europeus agglutinin I and 125I-peanut agglutinin. Thyroxine treatment had similar effects on fucose content and 125I-ulex europeus agglutinin I binding, but did not alter [3H] fucose incorporation or sialic acid content. At the doses used, epidermal growth factor and insulin had no significant effects. The effect of cortisone treatment on sialic acid and fucose was commensurate with a 5- to 6-day acceleration of postnatal intestinal maturation. The changes in lectin binding, however, suggested qualitative differences between developmental and cortisone-induced membrane glycosylation. In addition, this study demonstrates significant quantitative and qualitative differences in the response of intestinal glycosylation to pharmacologic doses of the four hormones.

Differential toxicity of RCAII (ricin) on rabbit intestinal epithelium in relation to postnatal maturation.

The purpose of this work was to assess the toxic lectin ricin (RCAII) as a probe for the study of intestinal permeability in the developing small bowel. Jejunal explants from suckling and adult rabbits were exposed to varying dosages of RCAII for 30 min at 25 degrees C and then cultured in toxin-free medium. The RCAII dose required to inhibit protein synthesis during 6 h of culture increased from 0.1 microgram/ml in 4-day-old rabbits to 25 micrograms/ml in weanling rabbits. RCAII cytotoxicity was almost completely blocked by 0.1 M lactulose in all age groups. The kinetics of 125I-RCAII binding to purified microvillus membranes were determined by incubating a fixed concentration of membrane protein (30 micrograms) with increasing concentrations of labeled lectin (2-18 micrograms/ml). Binding attained saturation with adult but not with suckling animal membranes. The latter yielded a curvilinear relationship in Scatchard plots, suggesting either several classes of binding sites or negative cooperativity. RCAII binding was confined to the delipidated fraction of the membranes and decreased by 42% from 6 days old to adult age. The extreme sensitivity of colostral epithelium to RCAII is probably related to the high level of endocytosis exhibited by the immature membrane of suckling rabbits. The development of increasing resistance to the toxin, and associated decrease in binding, might be related to disappearance of saccharide sites in productive surface receptors occurring in the developmental course of intestinal glycosylation.

Postnatal changes in biosynthesis of microvillus membrane glycans of rat small intestine: I. Evidence of a developmental shift from terminal sialylation to fucosylation.

We present evidence of a change from sialylation to fucosylation of intestinal microvillus membrane oligosaccharides during postnatal development in the rat. The initial high sialic acid to fucose molar ratio in native and delipidated membranes was completely reversed after weaning. The specific binding of 125I-labeled wheat germ agglutinin to neuraminidase-sensitive sites in the native and delipidated membranes decreased markedly from early suckling to weaning ages. The binding of 125I-labeled Ulex europeus agglutinin I showed an age-related pattern opposite to that of wheat germ agglutinin. The changes in membrane reactivities to these lectins were entirely consistent with the existence of a developmentally-controlled shift from terminal sialyl to fucosyl substitutions among various glycoconjugate classes. This could play a key role on the functional transformation experienced by the intestinal epithelium of suckling rats.