Antimicrobial Resistance Patterns and Antibiotic Use during Hospital Conversion in the COVID-19 Pandemic.

OBJECTIVE: To describe empirical antimicrobial prescription on admission in patients with severe COVID-19, the prevalence of Hospital-Acquired Infections, and the susceptibility patterns of the causing organisms. METHODS: In this prospective cohort study in a tertiary care center in Mexico City, we included consecutive patients admitted with severe COVID-19 between March 20th and June 10th and evaluated empirical antimicrobial prescription and the occurrence of HAI. RESULTS: 794 patients with severe COVID-19 were admitted during the study period. Empiric antibiotic treatment was started in 92% of patients (731/794); the most frequent regimes were amoxicillin-clavulanate plus atypical coverage in 341 (46.6%) and ceftriaxone plus atypical coverage in 213 (29.1%). We identified 110 HAI episodes in 74/656 patients (11.3%). Ventilator-associated pneumonia (VAP) was the most frequent HAI, in 56/110 (50.9%), followed by bloodstream infections (BSI), in 32/110 (29.1%). The most frequent cause of VAP were Enterobacteriaceae in 48/69 (69.6%), followed by non-fermenter gram-negative bacilli in 18/69 (26.1%). The most frequent cause of BSI was coagulase negative staphylococci, in 14/35 (40.0%), followed by Enterobacter complex in 7/35 (20%). Death occurred in 30/74 (40.5%) patients with one or more HAI episodes and in 193/584 (33.0%) patients without any HAI episode (p < 0.05). CONCLUSION: A high frequency of empiric antibiotic treatment in patients admitted with COVID-19 was seen. VAP and BSI were the most frequent hospital-acquired infections, due to Enterobacteriaceae and coagulase negative staphylococci, respectively.

Recomendaciones Rama de Dermatología Pediátrica, Sociedad Chilena de Pediatría. Pandemia COVID-19 / Recommendations Pediatric Dermatology Branch, Chilean Society of Pediatrics. COVID-19 pandemic

Resumen: La actual pandemia por Covid-19 (SARS-CoV-2) corresponde a una zoonosis viral altamente con tagiosa que ha requerido extremar las medidas de protección personal con el fin de disminuir la transmisión del virus, tanto en ambientes hospitalarios como fuera de ellos, siendo necesaria la adopción de estrictos métodos de aislamiento tanto de contacto como aerosoles. Esto ha reque rido la adopción de múltiples equipos de protección personal, dentro de los que se encuentran la protección ocular, mascarillas, escudo de protección facial, gorros, guantes, etcétera. Lo anterior ha generado un aumento en el daño de la barrera cutánea y, por lo tanto, la aparición de diversas dermatosis dentro de las que se encuentran dermatitis de contacto irritativa o alérgica, reaccio nes acneiformes, agravamiento de dermatosis previas, entre otras, cobrando así vital importancia el cuidado y restablecimiento de la barrera cutánea con medidas esenciales como aplicación de productos humectantes o emolientes y el correcto uso de los equipos en mención. No obstante, no solo se generan dermatosis derivadas del uso de equipos de protección personal, sino que tam bién, dentro del amplio espectro de manifestaciones dermatológicas que puede generar la enfer medad por Covid-19 propiamente tal, incluyendo compromiso cutáneo, piloso (efluvio telógeno) o ungueal (onicomadesis). Por otro lado pero no motivo de este artículo, el compromiso cutáneo puede corresponder a la primera expresión clínica de la enfermedad o ser un predictor de su evolu ción. Dentro de lo anterior encontramos la urticaria aguda, exantema maculo-papular, exantema varicela-like, erupción petequial, perniosis-like y lívedo reticularis como las principales formas de afección cutánea hasta el momento.

Abstract: The current Covid-19 pandemic (SARS-CoV-2) corresponds to a highly contagious viral zoonosis that has required to extreme measures in order to decrease the transmission of the virus in hospi tal settings and outside of them, requiring adoption of strict isolation methods, both contact and aerosols. This has required the adoption of multiple personal protective equipment, including eye protection, masks, face shield, medical caps, gloves, etc. The aforementioned has generated an in crease in the damage of the skin barrier, and therefore, the appearance of various dermatoses, among which are irritative o alergic contact dermatitis, acneiform reactions, aggravation of previous der matoses, and others, thus becoming vital protection and restoration of the skin barrier with mea sures such as the application of moisturizing or emollient products and the correct use of personal protection equipment. However, not only dermatoses are generated derived from the use of perso nal protection equipment, but also, within the wide spectrum of dermatological manifestations that Covid-19 disease itself can generate, including cutaneous, hairy involvement (telogen effluvium) or nail (onychomadesis). Cutaneous involvement may correspond to the first clinical expression of the disease or be a predictor of its evolution. Among the above we find acute urticaria, maculo-papular rash, chickenpox-like rash, petechial rash, perniosis-like, and livedo reticularis as the main forms of skin condition to date.

Ventanillas de Salud: A Collaborative and Binational Health Access and Preventive Care Program.

While individuals of Mexican origin are the largest immigrant group living in the U.S., this population is also the highest uninsured. Health disparities related to access to health care, among other social determinants, continue to be a challenge for this population. The government of Mexico, in an effort to address these disparities and improve the quality of life of citizens living abroad, has partnered with governmental and non-governmental health-care organizations in the U.S. by developing and implementing an initiative known as Ventanillas de Salud-Health Windows-(VDS). The VDS is located throughout the Mexican Consular network and aim to increase access to health care and health literacy, provide health screenings, and promote healthy lifestyle choices among low-income and immigrant Mexican populations in the U.S.

Ganancia inicial de peso del recién nacido de término hijo de madre adolescente / Early weight gain of infants born to adolescent mothers

Introducción: el embarazo de la adolescente es frecuente en Chile; sus hijos pueden tener mayor riesgo de lactancia materna insuficiente de cuidados inadecuados y mal incremento ponderal. Objetivo: Estudiar la ganancia de peso durante el 1er mes de vida de recién nacidos (RN) hijos de madres adolescentes y su asociación con riesgo de ictericia, hospitalización y abandono de lactancia materna. Sujetos y métodos: Se estudiaron 40 RN de término, hijos de madres primíparas adolescentes < 19 anos, de estratos socioeconómicos bajos, adecuados para la edad gestacional (AEG), sin patología aguda o malformaciones, (GE; H/M: 27/ 13) y se compararon con 36 RN de madres adultas primíparas (GC; H/M: 19/17), de un hospital público de Santiago. Fueron controlados en atención primaria (peso, talla) con mediana a los 8 y 30 días en ambos grupos, se consultó por ictericia, lactancia materna y hospitalización. Resultados: Al 8° día la ganancia de peso fue: GE -1,5 g/día (-107 vs +36) vs GC -5,7 g/d (-59 a +39) (NS), < al incremento esperado por OMS (14-21g/d), habían recuperado peso de nacimiento 52% de GE y 44% GC (NS). Al mes no hubo diferencias en el incremento diario (GE 31; -1,7 a 79 g/d, GC 28; -3 a 63 g/d NS), semejantes a estándares OMS (x: 34g/día en hombres y 29g/día en mujeres). Al subdividir GE en grupos de madres: de 15 a 16 y de 17 a 18 anos, se observó un mayor incremento diario el 1er mes en el grupo de 15 a 16 anos: 38 g/d (9-79) vs 17 a 18 anos: 25g/d (-1,7 a 57) (p< 0,02) y con el GC (p<0,02). No hubo diferencias en el riesgo de ictericia al 3° día: GE:12/40, GC: 7/36 (NS), pero hubo diferencia al 8° día, GE: 13/40, GC 2/36 (OR: 8,2 IC:1,7-39; p=0,003), sin mayor riesgo de hospitalización. Ambos grupos recibieron lactancia materna, con fórmula artificial en GE: 8/40, GC: 10/36 (NS). Conclusiones: Los hijos de madre adolescentes no presentan mayor riesgo de retraso en la recuperación de PN comparados con hijos de madres primíparas adultas, el sub-grupo de hijos de adolescentes de 15 a 16 anos tuvieron un mayor incremento de peso que el de 17 a 18 anos y el GC. Si bien el riesgo de ictericia al 8° día es mayor en el GE, este no constituyó un factor de hospitalización. Presentan buena adherencia a lactancia materna.

Background: Adolescent pregnancy is frequent in Chile, and their infants could present an increased risk of inadequate breast feeding and weight gain. Objectives: To assess the early weight gain in infants born to Chilean adolescent mothers and their association with breast feeding, risk ofjaundice and hospitalization. Subjects and methods: Fortyfull-term and adequatefor gestational age newborns (SG; M/F: 27/13), born to healthy adolescent mothers (less than < 19 y at delivery) (SG) from low socioeconomic groups, were recruited in a public hospital in Santiago, Chile. They were paired with 36 born to healthy primiparous adult mothers (control group CG; M/F:19/17); those born with low birth weight or congenital malformations were excluded. They were assessed at well baby clinics in primary care centers for weight, length, (median age: 8 and 30 d.; breast feeding, jaundice and hospitalization were registered). Results: No significant differences were found in weight gain at 8th day of age (SG: -15 g/d (-107 to +36); CG -5,7 g/d (-59 to +39) (NS), both lower than the weight increments of WHO standards (14-21 g/d); birth weight recovery was found in SG: 52%% and CG: 44% (NS). Neither a difference was found at 30 days (SG: 31g/d (-1.7 to +79), CG: 28 g/d (-3 to63); (NS), comparable to WHO standards (males: 34 g/d; females: 29 g/d). However, the sub-group of infants born to adolescent mothers 15-16 y. presented a greater weight gain than those to adolescents mothers 16-17 y. (38 g/d (9 to 79 vs 25 g/d ,-1,7 to + 57) than the CG (p<0.02). Formula breast feeding was provided to 8/40 in SG and 10/36 in CG (NS). No differences in jaundice was found at the 3rd day, but an increased rate was observed at the 8th day (SG 13/40 vs CG2/36) (OR 8.2; CI: 1.7-39; p=0.003), without an increased risk of hospitalization. Conclusions: Infants born to Chilean adolescent mothers have a comparable weight gain to infants born to adult mothers, with a comparable time of birth weight recovery. Those born to mothers 15-16 years of age had a greater weight gain than those born to mothers 17-18 years or adult mothers. Jaundice to the 8° day was greater in the SG with no increased rate of hospitalization. They present a good rate of breast feeding.

[Idiopathic hypertrophic pachymeningitis: a case report]. / Paquimeningitis hipertrófica idiopática: a propósito de un caso.

INTRODUCTION: Hypertrophic pachymeningitis is a clinical condition that is caused by a diffuse or localised thickening of the dura mater. It predominantly affects males and manifests as chronic headache, with or without association to neurological manifestations, such as paralysis of the cranial nerves, cerebellar ataxia and neuro-ophthalmic complications. CASE REPORT: A 61-year-old male, with no relevant past history, who, one month before admission, had begun to suffer from right frontotemporal headache that irradiated to the ipsilateral orbital region and was more pronounced at night. A week later he was affected by a decrease in visual acuity in the right eye and two weeks later he noted the presence of right palpebral ptosis, while the headaches increased. The examination showed: right palpebral ptosis with global ophthalmoparesis with predominance of adduction and abduction, and diminished photomotor reflex in the right eye. The visual acuity of the right eye was reduced and the palpebral fissure was 0 in the right eye. The fundus oculi was normal. Infectious and non-infectious causations of meningitis were precluded. Magnetic resonance imaging revealed a diffuse thickening of the supratentorial and infratentorial meninges, as well as diffuse uptake of the paramagnetic substance; thickening of the mucus in both paranasal maxillary sinuses was also observed. A meningeal biopsy study confirmed the existence of hypertrophic pachymeningitis. Treatment was established with prednisone and the clinical symptoms improved. CONCLUSIONS: Idiopathic hypertrophic pachymeningitis is an underdiagnosed condition that must be taken into consideration in cases of patients with a history of subacute or chronic meningitis in which infectious and non-infectious causations have been precluded, and high-dose steroid treatment must be established.

Paquimeningitis hipertrófica idiopática: a propósito de un caso / Idiopathic hyperthophic pachymeningitis: a case report

Introducción. La paquimeningitis hipertrófica es una entidad clínica que se debe a un engrosamiento difuso o localizado de la duramadre; suele afectar predominantemente a hombres y se manifiesta como una cefalea crónica, con o sin asociación a manifestaciones neurológicas, como parálisis de nervios craneales, ataxia cerebelosa y complicaciones neuroftalmológicas. Caso clínico. Varón de 61 años, sin antecedentes de interés, que comienza, un mes antes del ingreso, con cefalea frontotemporal derecha irradiada a la región orbitaria ipsilateral, de predominio nocturno. Una semana después se ve afectado por una disminución de la agudeza visual en el ojo derecho y dos semanas después nota ptosis palpebral derecha, con incremento de la cefalea. En la exploración se evidencian: ptosis palpebral derecha con oftalmoparesia global derecha con predominio de la aducción y abducción, y disminución de la respuesta fotomotora derecha. La agudeza visual en el ojo derecho se encuentra disminuida y la hendidura palpebral es 0 en el ojo derecho. El fondo de ojo es normal. Se descartan etiologías infecciosas y no infecciosas de meningitis. En la resonancia magnética se observa un engrosamiento difuso de las meninges supratentoriales e infratentoriales, así como una captación difusa de sustancia paramagnética; también se evidencia un engrosamiento de la mucosa en ambos senos paranasales maxilares. En la biopsia meníngea se confirma la existencia de paquimeningitis hipertrófica. Se instaura tratamiento con prednisona y la sintomatología mejora. Conclusiones. La paquimeningitis hipertrófica idiopática es una entidad subdiagnosticada que debe tenerse en cuenta en pacientes con historia de meningitis subagudas o crónicas en quienes se hayan descartado etiologías infecciosas y no infecciosas, y debe instaurarse tratamiento con esteroides en altas dosis (AU)

Introduction. Hypertrophic pachymeningitis is a clinical condition that is caused by a diffuse or localised thickening of the dura mater. It predominantly affects males and manifests as chronic headache, with or without association to neurological manifestations, such as paralysis of the cranial nerves, cerebellar ataxia and neuro-ophthalmic complications. Case report. A 61-year-old male, with no relevant past history, who, one month before admission, had begun to suffer from right frontotemporal headache that irradiated to the ipsilateral orbital region and was more pronounced at night. A week later he was affected by a decrease in visual acuity in the right eye and two weeks later he noted the presence of right palpebral ptosis, while the headaches increased. The examination showed: right palpebral ptosis with global ophthalmoparesis with predominance of adduction and abduction, and diminished photomotor reflex in the right eye. The visual acuity of the right eye was reduced and the palpebral fissure was 0 in the right eye. The fundus oculi was normal. Infectious and non-infectious causations ofmeningitis were precluded. Magnetic resonance imaging revealed a diffuse thickening of the supratentorial and infratentorial meninges, as well as diffuse uptake of the paramagnetic substance; thickening of the mucus in both paranasal maxillary sinuses was also observed. A meningeal biopsy study confirmed the existence of hypertrophic pachymeningitis. Treatment was established with prednisone and the clinical symptoms improved. Conclusions. Idiopathic hypertrophic pachymeningitis is an underdiagnosed condition that must be taken into consideration in cases of patients with a history of subacute or chronic meningitis in which infectious and non-infectious causations have been precluded, and high-dose steroid treatment must be established (AU)

20p12.3 microdeletion predisposes to Wolff-Parkinson-White syndrome with variable neurocognitive deficits.

BACKGROUND: Wolff-Parkinson-White syndrome (WPW) is a bypass re-entrant tachycardia that results from an abnormal connection between the atria and ventricles. Mutations in PRKAG2 have been described in patients with familial WPW syndrome and hypertrophic cardiomyopathy. Based on the role of bone morphogenetic protein (BMP) signalling in the development of annulus fibrosus in mice, it has been proposed that BMP signalling through the type 1a receptor and other downstream components may play a role in pre-excitation. METHODS AND RESULTS: Using the array comparative genomic hybridisation (CGH), we identified five individuals with non-recurrent deletions of 20p12.3. Four of these individuals had WPW syndrome with variable dysmorphisms and neurocognitive delay. With the exception of one maternally inherited deletion, all occurred de novo, and the smallest of these harboured a single gene, BMP2. In two individuals with additional features of Alagille syndrome, deletion of both JAG1 and BMP2 were identified. Deletion of this region has not been described as a copy number variant in the Database of Genomic Variants and has not been identified in 13 321 individuals from other cohort examined by array CGH in our laboratory. CONCLUSIONS: Our findings demonstrate a novel genomic disorder characterised by deletion of BMP2 with variable cognitive deficits and dysmorphic features and show that individuals bearing microdeletions in 20p12.3 often present with WPW syndrome.

The in vitro protective effect of alpha-tocopherol on oxidative injury in the dog retina.

Oxidative stress is a risk factor for eye diseases. Free radicals elicited during the inflammatory process often lead to oxidative damage of lipids (lipid peroxidation). The retina is highly vulnerable because of its high content of polyunsaturated fatty acids (PUFAs). The aim of this study was to investigate in vitro the effect of alpha-tocopherol on the Fe(2+)-ascorbate induced lipid peroxidation in the canine retina. Lipid peroxidation of retinal homogenates was carried out with and without the addition of alpha-tocopherol and monitored both by chemiluminescence and production of thiobarbituric acid reactive substances (TBARS). Total chemiluminescence counts per minute was lower in those homogenates pre-incubated with alpha-tocopherol. Thus, with 1 micromol alpha-tocopherol/mg of protein, 100% inhibition of chemiluminescence and a decrease of TBARS content from 20.46+/-0.85 to 2.62+/-2.77 nmol/mg protein were observed. Simultaneously, changes produced by oxidative stress were noted in the fatty acid composition of retinal lipids. Docosahexaenoic acid was decreased from 14.33+/-2.32% to 1.84+/-0.14% after peroxidation, but this fatty acid remained unaltered in the presence of 1 micromol alpha-tocopherol. These results show that under these experimental conditions, alpha-tocopherol may act as anti-oxidant protecting retinal membranes from deleterious effects. Further studies are required to assess its use in free radical generating conditions affecting the canine retina.

Estudio de cepas nativas amilolíticas / Study of amilolytic native microbial stocks

En el presente trabajo se realiza el estudio de cepas microbianas aisladas de diferentes nichos ecológicos, productoras de las enzimas amilolíticas, así: procesado de maíz, de papa y de yuca. Los criterios utilizados para el aislamiento de las cepas amilolíticas, son el crecimiento sobre los medios modificados con almidón y la positividad frente al Test de Lugol. Los medios empleados fueron CZAPEK, PCA y MRS modificados. Las cepas obtenidas son debidamente purificadas, crío conservadas e identificadas bioquímicamente, obteniendo un total de 103 cepas nativas. De éste total de cepas, se seleccionan debido a la similitud fisiológica entre microorganismos aislados, 9 cepas. Estas últimas son identificadas bioquímicamente y se obtienen los géneros Bacillus sp ,Clostridium sp y Kurthia sp. Las enzimas amilolíticas obtenidas a partir de las cepas nativas presentan pesos moleculares que oscilan entre 30 y 150 kDa aproximadamente

Fistula enterocutanea en abdomen abierto / Enterocutanea fistula in trauma

Se analizó una serie clínica de 23 pacientes con diagnóstico de abdomen abierto complicado con fístula intestinal para evaluar su respuesta a la terapia nutricional en lo que respecta al comportamiento de la fístula y a la incidencia sobre la mortalidad global y otras variables de la hospitalización. La edad promedio fue de 44 años. El análisis inicial mostró una preponderancia de la etiología posquirúrgica no traumática sobre la traumática (61 por ciento vs. 39 por ciento). Un 56 por ciento de pacientes se diagnosticó como malnutrido, con una albúmina de ingreso promedio de 1.9 gr/dl. La fístula fue de alto gasto en el 78 por ciento de los casos, 83 por ciento(21) requirió más de 2 cirugías, con un promedio de 4.7 cirugías / paciente. El soporte nutricional mixto fue el más frecuente 16 (74 por ciento) con un promedio de 1282 cal. /día, 14.3 gramos/ N/día y 17 días/pte. El porcentaje global de cierre fue del 65 por ciento (15), 8 (35 por ciento) con tratamiento conservador y 7 (30 por ciento) con cierre quirúrgico. La estancia hospitalaria fue de 62 días (rango 11-168), los costos de atención oscilan entre (pesos colombianos) 1.619.391 y 58.939.583 y el costo global de atención se calculó en 451.341.680 pesos colombianos. El 60 por ciento (15) de los pacientes tuvieron un costo de atención superior a los 15.000.000. La mortalidad fue del 34 por ciento (8), similar a la reportada mundialmente. El análisis del impacto del soporte nutricional sobre la mortalidad y la estancia no mostró ninguna correlación estadísticamente significativa con variables como tiempo de inicio del soporte, calorías administradas, tipo de cierre, tipo de soporte. Otras usualmente pronosticó como albúmina, proteínas y balance nitrogenado al ingreso y egreso tampoco mostraron correlación con la muerte, la tasa de cierre y el pronóstico. Los datos obtenidos permiten concluir que el abdomen abierto complicado con fístula intestinal en una entidad que demanda un enorme cuidado y manejo multidisciplinario en la que el soporte nutricional intensivo pese a la dificultad en la medición de su valor aditivo a la terapia, es una importante herramienta en el afán de disminuir el perfil de mobimortalidad de este síndrome

Adapting pharmacokinetic properties of a humanized anti-interleukin-8 antibody for therapeutic applications using site-specific pegylation.

A neutralizing anti-interleukin-(IL-)8 monoclonal antibody was humanized by grafting the complementary determining regions onto the human IgG framework. Subsequent alanine scanning mutagenesis and phage display enabled the production of an affinity matured antibody with a >100-fold improvement in IL-8 binding. Antibody fragments can be efficiently produced in Escherichia coli but have the limitation of rapid clearance rates in vivo. The Fab' fragment of the antibody was therefore modified with polyethylene glycol (PEG) in order to obtain a more desirable pharmacokinetic profile. PEG (5-40 kDa) was site-specifically conjugated to the Fab' via the single free cysteine residue in the hinge region. In vitro binding and bioassays showed little or no loss of activity. The pharmacokinetic profiles of the 20 kDa, 30 kDa, 40 kDa, and 40 kDa branched PEG-Fab' molecules were evaluated in rabbits. Relative to the native Fab', the clearance rates of the PEGylated molecules were decreased by 44-175-fold. In a rabbit ear model of ischemia/reperfusion injury, all PEGylated Fab' molecules were as efficacious in reducing oedema as the original monoclonal antibody. These studies demonstrate that it is possible to customize the pharmacokinetic properties of a Fab' while retaining its antigen binding activity.

Expanded bed adsorption in the purification of monoclonal antibodies: a comparison of process alternatives.

Expanded bed adsorption (EBA) was examined as the initial capture/purification step in the purification of monoclonal antibodies from Chinese hamster ovary (CHO) cultures. Two process alternatives each using EBA were compared to a conventional Protein A process without EBA. One alternative used Protein A affinity EBA followed by packed-bed cation and anion-exchange steps. The other alternative used cation-exchange EBA as the capture step followed by packed-bed Protein A and anion-exchange steps. The process using Protein A EBA produced comparable purity (host cell protein, DNA, Protein A, antibody aggregate) to the conventional process. However, the Protein A EBA column showed a significant decrease in dynamic capacity with a limited number of cycles. The process using cation EBA achieved comparable levels of host cell proteins (HCP) and DNA but not antibody aggregate or leached Protein A compared to the conventional process.

Modulating pharmacokinetics of an anti-interleukin-8 F(ab')(2) by amine-specific PEGylation with preserved bioactivity.

By covalently attaching biocompatible polyethylene-glycol (PEG) groups to epsilon-amino groups of the F(ab')(2) form of a humanized anti-interleukin-8 (anti-IL-8) antibody, we sought to decrease the in vivo clearance rate to give a potentially more clinically acceptable therapeutic. The in vivo clearance was modulated by changing the hydrodynamic size of the PEGylated antibody fragments. To achieve significant increases in the hydrodynamic size with minimal loss in bioactivity, high molecular weight linear or branched PEG molecules were used. Modification involved N-hydroxy-succinamide reaction of the PEGs with primary amines (lysines and/or the N-terminus) of the anti-IL-8 F(ab')(2). The process of adding up to four linear 20 kDa PEG, or up to two branched 40 kDa PEG, gave reproducible distribution of products. The components with uniform size (as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) were purified by a single-step ion-exchange high-performance liquid chromatography and showed no significant loss of biological activity in ligand binding and cell-based assays. Addition of a single branched 40 kDa PEG to a F(ab')(2) (molecular weight (MW)=1.6 million Da) or up to two 40 kDa branched PEG (MW=1.9 million Da) increased the serum half-life to 48 h as compared with the unPEGylated F(ab')(2) with a half-life of 8.5 h. This study shows that by attaching high molecular weight PEGs at a one or two sites, bioactive antibody fragments can be made reproducibly with sizes tailored to achieve the desired pharmacokinetics.

Diagnóstico y tratamiento de la lesión labral acetabular / Diagnostic and treatment of the acetabular lebrum lesion

Se describe un caso de lesión labral acetabular, haciendo un estudio sobre el diagnóstico y tratamiento de esta lesión

Expanded bed protein A affinity chromatography of a recombinant humanized monoclonal antibody: process development, operation, and comparison with a packed bed method.

We show that expanded bed protein A affinity chromatography using Streamline rProtein A media is an efficient method for purifying a recombinant humanized monoclonal antibody from unclarified Chinese hamster ovary cell culture fluid and that it provides purification performance comparable to using a packed bed. We determined that the dynamic capacity of the expanded bed media is related to flow rate (measured in column volumes per hour) by a power function, which allows a high capacity at a low flow rate. At 250 cm h-1 with a 25 cm bed height (10 column volumes h-1), the dynamic capacity is 30 g l-1. The yield and purity (measured by the amount of host cell proteins, DNA, SDS-PAGE, and turbidity) of the antibody purified by expanded bed is comparable to the yield and purity obtained on a standard packed bed method using Prosep A media.

Identification of Arg-12 in the active site of Escherichia coli K1 CMP-sialic acid synthetase.

Escherichia coli K1 CMP-sialic acid synthetase catalyses the synthesis of CMP-sialic acid from CTP and sialic acid. The active site of the 418 amino acid E. coli enzyme was localized to its N-terminal half. The bacterial CMP-sialic acid synthetase enzymes have a conserved motif, IAIIPARXXSKGLXXKN, at their N-termini. Several basic residues have been identified at or near the active site of the E. coli enzyme by chemical modification and site-directed mutagenesis. Only one of the lysines in the N-terminal motif, Lys-21, appears to be essential for activity. Mutation of Lys-21 in the N-terminal motif results in an inactive enzyme. Furthermore, Arg-12 of the N-terminal motif appears to be an active-site residue, based on the following evidence. Substituting Arg-12 with glycine or alanine resulted in inactive enzymes, indicating that this residue is required for enzymic activity. The Arg-12-->Lys mutant was partially active, demonstrating that a positive charge is required at this site. Steady-state kinetic analysis reveals changes in k(cat), K(m) and K(s) for CTP, which implicates Arg-12 in catalysis and substrate binding.

Na2Zn3(CO3)4.3H2O: a potentially useful compound for zinc supplementation.

The infrared and Raman spectra of the title compound were recorded and are briefly discussed on the basis of its structural characteristics. Its thermal behaviour was investigated by means of TG and DTA measurements. Several dissolution tests were also performed. The results support the potential usefulness of this double carbonate as a useful compound for Zn(II) supplementation.

Purification of CMP-N-acetylneuraminic acid synthetase from bovine anterior pituitary glands.

CMP-beta-N-acetylneuraminic acid (CMP-neuNAc) is the substrate for the sialylation of glycoconjugates by sialyltransferases in microbes and higher eukaryotes. CMP-neuNAc synthetase catalyzes the formation of this substrate, CMP-neuNAc, from CTP and neuNAc. In this report we describe the purification of CMP-neuNAc synthetase from bovine anterior pituitary glands. The enzyme was purified by ion exchange, gel filtration, and affinity chromatography. The protein was homogeneous on SDS-PAGE with a molecular weight of 52 kDa, a subunit size similar to that of the E.coli K1 (48.6 kDa). The identity of the 52 kDa protein band was confirmed by native gel electrophoresis in that the position of the enzyme activity in gel slices coincided with the position of major bands in the stained gel. Photoaffinity labeling with 125I-ASA-CDP ethanolamine resulted in the modification of a 52 kDa polypeptide that was partially protected against modification by the substrate CTP. Enzyme activity in crude fractions could be adsorbed onto an immunoadsorbent prepared from antibody against the purified 52 kDa protein. Taken together these data suggest that the 52 kDa polypeptide purified by this procedure described in this report is indeed CMP-neuNAc synthetase. The active enzyme chromatographed on a gel filtration column at 158 kDa suggesting it exists in its native form as an oligomer.

Extracting fuzzy control rules from experimental human operator data.

This paper proposes an approach where the interpretation of manual control strategies is carried out by modeling the human operator as a fuzzy logic controller. The linguistic rules thus obtained can provide a better insight into the operator's actions, allowing mistakes to be more easily pinpointed and corrected. Instead of extracting the control rules directly from raw experimental data, an intermediary ARMA model for the operator is employed to improve the data consistency. For illustration, this method is applied to the problem of supervising an apprentice operator, with basis on rules extracted from the actions of an experienced manual operator.

Remodeling domain interfaces to enhance heterodimer formation.

An anti-p185HER2/anti-CD3 humanized bispecific diabody was previously constructed from two cross-over single-chain Fv in which YH and VL domains of the parent antibodies are present on different polypeptides. Here this diabody is used to evaluate domain interface engineering strategies for enhancing the formation of functional heterodimers over inactive homodimers. A disulfide-stabilized diabody was obtained by introducing two cysteine mutations, VL L46C and VH D101C, at the anti-p185HER2.VL/VH interface. The fraction of recovered diabody that was functional following expression in Escherichia coli was improved for the disulfide-stabilized compared to the parent diabody (> 96% versus 72%), whereas the overall yield was > 60-fold lower. Eleven "knob-into-hole" diabodies were designed by molecular modeling of sterically complementary mutations at the two VL/VH interfaces. Replacements at either interface are sufficient to improve the fraction of functional heterodimer, while maintaining overall recoverable yields and affinity for both antigens close to that of the parent diabody. For example, diabody variant v5 containing the mutations VL Y87A:F98M and VH V37F:L45W at the anti-p185HER2 VL/VH interface was recovered as 92% functional heterodimer while maintaining overall recovered yield within twofold of the parent diabody. The binding affinity of v5 for p185HER2 extracellular domain and T cells is eightfold weaker and twofold stronger than for the parent diabody, respectively. Domain interface remodeling based upon either sterically complementary mutations or interchain disulfide bonds can facilitate the production of a functional diabody heterodimer. This study expands the scope of domain interface engineering by demonstrating the enhanced assembly of proteins interacting via two domain interfaces.