Estabilidad fisicoquímica y microbiológica de un colirio de insulina 10 UI/mL / Physicochemical and microbiological stability of a 10 IU/mL insulin eye drop

Objetivo: Los pacientes con defectos epiteliales corneales persistentes son, a menudo, refractarios a los tratamientos convencionales. La insulina tópica surge como una posible alternativa, habiendo demostrado su efectividad y seguridad. Sin embargo, en la bibliografía actual disponible, hay una falta de estudios de estabilidad. El objetivo del presente trabajo fue evaluar la estabilidad fisicoquímica y microbiológica de un colirio de insulina 10 UI/ml durante 28 días. Método: Estudio de estabilidad fisicoquímica y microbiológica. Se elaboraron 2 lotes (A y B) de colirios de insulina 10 UI/ml, manteniendo el lote B cerrado hasta el día 15. Las variables fisicoquímicas analizadas fueron la concentración de insulina mediante inmunoanálisis quimioluminiscente, pH y osmolaridad. El estudio microbiológico se realizó mediante pruebas de esterilidad mientras que el estudio descriptivo se analizó mediante visualización directa. Resultados: No se observaron cambios significativos de concentración (±10%) en los colirios a excepción de 2 valores en una de las muestras del lote B. El pH y la osmolaridad se mantuvieron dentro de los rangos fisiológicos del ojo. No se observó crecimiento microbiano ni cambios en las características organolépticas. Conclusiones: Se puede considerar al colirio de insulina 10 UI/ml estable durante 28 días en refrigeración manteniendo el frasco abierto desde el día de su elaboración.(AU)

Objective: Patients with persistent corneal epithelial defects are often refractory to conventional treatments. Topical insulin emerges as a possible alternative of proven effectiveness and safety. However, in the current available literature, there is a lack of stability studies. The main objective of this study was to evaluate the physicochemical and microbiological stability of a 10 IU/ml insulin eye drop for 28 days. Methods: Physicochemical and microbiological stability study. Two batches (A and B) of 10 IU/ml insulin eye drops were prepared, keeping batch B closed until day 15. The physicochemical variables analysed were insulin concentration by chemiluminescent immunoassay, pH and osmolarity. The microbiological study was performed by sterility tests while the descriptive study was assessed by direct visualization. Results: No significant concentration changes (±10%) were observed in the eye drops except for 2 values in one of the samples from batch B. The pH and osmolarity remained within the physiological ranges of the eye. No microbiological growth or changes in organoleptic characteristics were observed. Conclusions: Insulin 10 UI/ml eye drops can be considered stable for 28 days under refrigeration if the bottle is kept open from the day of its preparation.(AU)

Pronóstico de la enfermedad tromboembólica venosa en cirugía ortopédica o pacientes traumatológicos y uso de tromboprofilaxis / Prognosis of venous thromboembolism in orthopaedic surgery or trauma patients and use of thromboprophylaxis

Antecedentes: Hay escasa evidencia sobre el pronóstico de la tromboembolia venosa en pacientes sometidos a cirugía ortopédica y en pacientes que sufren un trauma no quirúrgico. Métodos: Utilizamos la base de datos RIETE (Registro Informatizado de pacientes con Enfermedad TromboEmbólica) para comparar el pronóstico del tromboembolismo venoso y el uso de tromboprofilaxis en pacientes sometidos a diferentes procedimientos ortopédicos y en pacientes con traumatismo que no requiere cirugía. Resultados: Desde marzo de 2001 a marzo de 2015, se inscribieron un total de 61.789 pacientes en RIETE. De estos, 943 (1.52%) desarrollaron tromboembolismo venoso después de artroplastia electiva, 445 (0.72%) después de fractura de cadera, 1.045 (1.69%) después de cirugía ortopédica no mayor y 2,136 (3.46%) después de trauma no quirúrgico. En general, 2.283 pacientes (50%) presentaron inicialmente embolia pulmonar. En los primeros 90 días de tratamiento, 30 pacientes (0.66%, IC 95% 0.45-0.93) murieron por embolia pulmonar. La tasa de embolia pulmonar fatal fue significativamente mayor después de cirugía de fractura de cadera (n = 9 [2.02%]) que después de la artroplastia electiva (n = 5 [0.53%]), cirugía ortopédica no mayor (n = 5 [0.48%]) o traumatismo no quirúrgico (n = 11 [0,48%]). La tromboprofilaxis se utilizó con mayor frecuencia para la fractura de cadera (93%) o la artroplastia electiva (94%) que para la cirugía ortopédica no mayor (71%) o traumatismo no quirúrgico (32%). La hemorragia mayor fue significativamente mayor después de la cirugía de fractura de cadera (4%) que después de artroplastia electiva (1,6%), cirugía ortopédica no mayor (1,5%) o traumatismo no quirúrgico (1,4%). Conclusiones: La tromboprofilaxis se utilizó con menos frecuencia en los procedimientos de menor riesgo a pesar del número absoluto de embolia pulmonar fatal después de cirugía ortopédica no mayor o traumatismo no quirúrgico, excedieron los observados después de procedimientos de alto riesgo

Background: There is scarce evidence about the prognosis of venous thromboembolism in patients undergoing orthopedic surgery and in patients suffering non-surgical trauma. Methods: We used the RIETE database (Registro Informatizado de pacientes con Enfermedad Trombo Embólica) to compare the prognosis of venous thromboembolism and the use of thromboprophylaxis in patients undergoing different orthopedic procedures and in trauma patients not requiring surgery. Results: From March 2001 to March 2015, a total of 61,789 patients were enrolled in RIETE database. Of these, 943 (1.52%) developed venous thromboembolism after elective arthroplasty, 445 (0.72%) after hip fracture, 1,045 (1.69%) after non-major orthopedic surgery and 2,136 (3.46%) after non-surgical trauma. Overall, 2,283 patients (50%) initially presented with pulmonary embolism. Within the first 90 days of therapy, 30 patients (0.66%; 95% CI 0.45-0.93) died from pulmonary embolism. The rate of fatal pulmonary embolism was significantly higher after hip fracture surgery (n = 9 [2.02%]) than after elective arthroplasty (n = 5 [0.53%]), non-major orthopedic surgery (n = 5 [0.48%]) or non surgical trauma (n = 11 [0.48%]). Thromboprophylaxis was more commonly used for hip fracture (93%) or elective arthroplasty (94%) than for non-major orthopedic surgery (71%) or non-surgical trauma (32%). Major bleeding was significantly higher after hip fracture surgery (4%) than that observed after elective arthroplasty (1.6%), non-major orthopedic surgery (1.5%) or non-surgical trauma (1.4%). Conclusions: Thromboprophylaxis was less frequently used in lower risk procedures despite the absolute number of fatal pulmonary embolism after non-major orthopedic surgery or non-surgical trauma, exceeded that observed after high risk procedures

Prognosis of venous thromboembolism in orthopaedic surgery or trauma patients and use of thromboprophylaxis. / Pronóstico de la enfermedad tromboembólica venosa en cirugía ortopédica o pacientes traumatológicos y uso de tromboprofilaxis.

BACKGROUND: There is scarce evidence about the prognosis of venous thromboembolism in patients undergoing orthopedic surgery and in patients suffering non-surgical trauma. METHODS: We used the RIETE database (Registro Informatizado de pacientes con Enfermedad Trombo Embólica) to compare the prognosis of venous thromboembolism and the use of thromboprophylaxis in patients undergoing different orthopedic procedures and in trauma patients not requiring surgery. RESULTS: From March 2001 to March 2015, a total of 61,789 patients were enrolled in RIETE database. Of these, 943 (1.52%) developed venous thromboembolism after elective arthroplasty, 445 (0.72%) after hip fracture, 1,045 (1.69%) after non-major orthopedic surgery and 2,136 (3.46%) after non-surgical trauma. Overall, 2,283 patients (50%) initially presented with pulmonary embolism. Within the first 90 days of therapy, 30 patients (0.66%; 95% CI 0.45-0.93) died from pulmonary embolism. The rate of fatal pulmonary embolism was significantly higher after hip fracture surgery (n = 9 [2.02%]) than after elective arthroplasty (n = 5 [0.53%]), non-major orthopedic surgery (n = 5 [0.48%]) or non surgical trauma (n = 11 [0.48%]). Thromboprophylaxis was more commonly used for hip fracture (93%) or elective arthroplasty (94%) than for non-major orthopedic surgery (71%) or non-surgical trauma (32%). Major bleeding was significantly higher after hip fracture surgery (4%) than that observed after elective arthroplasty (1.6%), non-major orthopedic surgery (1.5%) or non-surgical trauma (1.4%). CONCLUSIONS: Thromboprophylaxis was less frequently used in lower risk procedures despite the absolute number of fatal pulmonary embolism after non-major orthopedic surgery or non-surgical trauma, exceeded that observed after high risk procedures.

Disección coronaria espontánea en el puerperio quirúrgico mediato / Spontaneous coronary dissection in the mediate surgical puerperium

Resumen: La disección coronaria espontánea, también llamada disección coronaria primaria, se trata de una afección subdiagnosticada, dadas las características variables de manifestación clínica, que incluyen dolor precordial, síndrome coronario agudo, arritmias ventriculares y muerte súbita. Afecta frecuentemente a mujeres entre 30 y 40 años de edad, y con frecuencia afecta a mujeres embarazadas o que cursan el puerperio, que además se caracterizan por no tener factores de riesgo cardiovascular. Este artículo comunica el caso de una paciente de 43 años de edad en la que se estableció el diagnóstico de disección coronaria espontánea y realizamos una revisión del tema.

Abstract: Spontaneous coronary dissection or primary coronary dissection is an underdiagnosed condition, given the variable characteristics of clinical presentation including precordial pain, acute coronary syndrome, ventricular arrhythmias and sudden death. It frequently affects women between the ages of 30 and 40, and frequently affects pregnant or postpartum women, who are also characterized by a lack of cardiovascular risk factors. The following article discusses the case of a 43-year-old woman in whom a diagnosis of spontaneous coronary dissection was established, and we performed a brief review of the topic.

La adiponectina como blanco terapéutico / Adiponectin as therapeutic target

Resumen: La adiponectina es una adipocina con acciones ubicuas, con propiedades antiinflamatorias y efectos antiapoptósicos. Entre sus acciones, esta proteína aumenta la sensibilidad a la insulina y disminuye el riesgo cardiovascular. Las concentraciones reducidas de adiponectina se asocian con mayor riesgo de diabetes mellitus tipo 2, síndrome metabólico, aterosclerosis y enfermedades cardiovasculares. Debido a esta evidencia, los esfuerzos de los estudios básicos y clínicos se han enfilado a ampliar la comprensión del metabolismo de esta proteína, así como al desarrollo de métodos para modular su concentración y su bioactividad como prometedoras herramientas terapéuticas. El objetivo de este trabajo es revisar el metabolismo de la adiponectina y explorar su utilidad como objetivo terapéutico.

Abstract: Adiponectin is an adipokine with ubiquitous actions, anti-inflammatory properties and antiapoptotic effects. Among its actions, this protein increases insulin sensitivity and reduces cardiovascular risk. A reduced level of adiponectin is associated with an increased risk of developing type 2 diabetes mellitus, metabolic syndrome, atherosclerosis and cardiovascular disease. Due to this evidence, the efforts of the basic and clinical studies have been directed to increase the understanding of the metabolism of this protein, as well as to develop methods to modulate its concentration and its bioactivity. The aim of this work is to review the metabolism of adiponectin and to explore its usefulness as a therapeutic target.

Enfermedad de Kikuchi-Fujimoto / Kikuchi-Fujimoto disease

Resumen: La enfermedad de Kikuchi-Fujimoto es poco común, de curso natural con alivio espontáneo, de causa desconocida, que se manifiesta por linfadenopatías, fiebre y síntomas menos específicos como diaforesis nocturna, pérdida de peso, cefalea, fatiga, náusea y artralgias. La única forma de establecer el diagnóstico es mediante los hallazgos histopatológicos, caracterizados por necrosis coagulativa con abundantes restos de cariorrexis en zonas paracorticales. El tratamiento es sintomático y debe realizarse diagnóstico diferencial con procesos infecciosos y neoplasias. Se comunica el caso de una mujer de 37 años de edad en la que se integró el diagnóstico de enfermedad de Kikuchi-Fujimoto y se realiza una revisión de la bibliografía.

Abstract: Kikuchi-Fujimoto disease is a rare, self-limiting disease of unknown etiology, manifested by lymphadenopathy, fever and less specific symptoms such as nocturnal diaphoresis, weight loss, headache, fatigue, nausea and arthralgias. The only way to establish the diagnosis is through the histopathological findings, characterized by coagulative necrosis with abundant remains of karyorrhexis in paracortical zones. The treatment is symptomatic, and a differential diagnosis must be made with infectious and neoplastic processes. We present the case of a 37-year-old woman in whom the diagnosis of Kikuchi-Fujimoto disease was integrated, and a review of the literature is made.

Probabilidad de éxito de obtener un hemocultivo positivo / Probability of success of obtaining a positive hemoculture

Resumen ANTECEDENTES: la sepsis se define como la existencia posible o documentada de una infección junto con manifestaciones sistémicas de infección. El hemocultivo es el estudio de primera línea en pacientes con sospecha de infección; el objetivo principal de los hemocultivos consiste en confirmar bacteremia. En la bibliografía se reporta que la sensibilidad para el diagnóstico de bacteremias es baja, con crecimiento en cultivos menor a 10%; en otras palabras, los hemocultivos son positivos en únicamente una tercera parte de los casos. OBJETIVO: determinar la tasa de hemocultivos positivos en el Hospital Ángeles Pedregal de la Ciudad de México, así como describir los microorganismos encontrados con mayor frecuencia y sus resistencias. MATERIAL Y MÉTODO: estudio retrospectivo, observacional y descriptivo, en el que se revisaron todos los hemocultivos realizados en el hospital citado, de enero a diciembre de 2015. RESULTADOS: de la muestra total (1,598 hemocultivos), únicamente 213 resultaron positivos, con lo que se reportó una probabilidad de éxito de 13%. Los microorganismos más frecuentes fueron Escherichia coli (43%), de los que 35 (16%) fueron organismos resistentes (BLEE), Burkholderia cepacia (6%) y Enterococcus faecalis (5%) en el grupo de los gramnegativos y Staphylococcus epidermidis (9%) y Staphyloccocus aureus (6%) en el grupo de los grampositivos. CONCLUSIONES: el número de hemocultivos que resultan positivos en el Hospital Ángeles Pedregal de la Ciudad de México es ligeramente mayor al reportado en la bibliografía. Además, se encontró mayor positividad para Escherichia coli, lo que confirma que las poblaciones de microorganismos son diferentes en cada hospital.

Abstract BACKGROUND: Sepsis is defined as the possible or documented presence of infection along with systemic manifestations of infection. Blood culture is the first-line study in patients with suspected infection, the main objective of blood cultures consists of confirming bacteremia. Literature reports that sensitivity for diagnosis of bacteremias is low, with a growth in crops <10%; in other words, blood cultures are positive in only 1/3 of the cases. OBJECTIVES: To determine the rate of positive blood cultures at Hospital Angeles Pedregal, Mexico City, as well as to describe the most commonly found microorganisms and their resistances. MATERIAL AND METHOD: A descriptive observational retrospective study was carried out. We reviewed all blood cultures performed at the Hospital Angeles Pedregal, Mexico, City, from January 2015 to December 2015. RESULTS: Of the total sample (1,598 blood cultures), only 213 were positive, finding a probability of success of 13%. The most common microorganisms were Escherichia coli (43%) of whom 35 (16%) were resistant organisms (BLEE), Burkholderia cepacia (6%) and Enterococcus faecalis (5%) in the gram-negative group. Staphylococcus epidermidis (9%) and Staphyloccocus aureus (6%) in the gram-positive group. CONCLUSIONS: Number of blood positive cultures at Hospital Angeles Pedregal, Mexico City, is slightly higher than that reported in literature. In addition, more positivity was found for Escherichia coli, confirming that the populations of microorganisms will be different at each hospital.

Prolonged exposure to GH impairs insulin signaling in the heart.

Acromegaly is associated with cardiac hypertrophy, which is believed to be a direct consequence of chronically elevated GH and IGF1. Given that insulin is important for cardiac growth and function, and considering that GH excess induces hyperinsulinemia, insulin resistance, and cardiac alterations, it is of interest to study insulin sensitivity in this tissue under chronic conditions of elevated GH. Transgenic mice overexpressing GH present cardiomegaly and perivascular and interstitial fibrosis in the heart. Mice received an insulin injection, the heart was removed after 2  min, and immunoblotting assays of tissue extracts were performed to evaluate the activation and abundance of insulin-signaling mediators. Insulin-induced tyrosine phosphorylation of the insulin receptor (IR) was conserved in transgenic mice, but the phosphorylation of IR substrate 1 (IRS1), its association with the regulatory subunit of the phosphatidylinositol 3-kinase (PI3K), and the phosphorylation of AKT were decreased. In addition, total content of the glucose transporter GLUT4 was reduced in transgenic mice. Insulin failed to induce the phosphorylation of the mammalian target of rapamycin (mTOR). However, transgenic mice displayed increased basal activation of the IR/IRS1/PI3K/AKT/mTOR and p38 signaling pathways along with higher serine phosphorylation of IRS1, which is recognized as an inhibitory modification. We conclude that GH-overexpressing mice exhibit basal activation of insulin signaling but decreased sensitivity to acute insulin stimulation at several signaling steps downstream of the IR in the heart. These alterations may be associated with the cardiac pathology observed in these animals.

Intususcepción ileal por tumor carcinoide en paciente con insuficiencia renal crónica / No disponible

No disponible

Vitamin D3 cannot revert desensitization of growth hormone (GH)-induced STAT5-signaling in GH-overexpressing mice non-calcemic tissues.

Growth hormone (GH) binding to a membrane receptor dimer triggers multiple intracellular signaling pathways. Signal transducers and activators of transcription are the most relevant of these pathways for GH action. GH also activates several inhibitory mechanisms, particularly suppressors of cytokine signaling (SOCS/CIS) proteins. GH-overexpressing mice exhibit hepatic desensitization of the JAK2/STAT5 GH-signaling pathway, associated with an increased abundance of CIS. Vitamin D3 has been shown to inhibit GH-induced expression of CIS and SOCS-3 and therefore prolong GH signaling in osteoblast-like cells. The purpose of the present study is to determine if vitamin D3 could attenuate CIS expression in GH-overexpressing mice, and consequently allow GH JAK2/STAT5 signaling in GH-responsive tissues in these animals. The abundance of CIS, SOCS-2, SOCS-3, STAT5b and GHR, as well as STAT5b tyrosine phosphorylation after a GH stimulus, were measured in liver and muscle of GHRH-transgenic mice treated with 1alpha,25-dihydroxyvitamin D3 for 7 days. This treatment did not diminish CIS expression in GH-overexpressing mice tissues, nor did the content of SOCS-2 and SOCS-3 significantly vary. GH-induced STAT5b phosphorylation levels were similar to basal values in transgenic mice liver treated with or without vitamin D; the refractoriness to GH was also present in muscle. Therefore, treatment with vitamin D was not sufficient to revert STAT5 GH signaling desensitization in non-calcemic tissues in GH-overexpressing mice.

Differential regulation of membrane associated-growth hormone binding protein (MA-GHBP) and growth hormone receptor (GHR) expression by growth hormone (GH) in mouse liver.

Growth hormone (GH) binding to GH receptor (GHR) is the initial step that leads to the physiological functions of the hormone. Proteolytical cleavage of the GHR in humans and rabbits and alternative processing of the GHR transcript in rodents generates circulating growth hormone binding protein (GHBP). Moreover, other GHR truncated forms that result from alternative processing of the GHR mRNA transcript have been described. These GHR short forms are inserted in the plasma membrane but they are unable to transduce the signal. In rodents, membrane associated-GHBP (MA-GHBP), which accounts for a significant proportion of liver GH binding capacity, represents the main GHR short form found in membranes, and may therefore function as a negative form of the receptor. In the present study, GHR and MA-GHBP content in liver were analyzed using mutant and transgenic mice expressing different concentrations of growth hormone to evaluate the correlation between GH levels, body weight (BW), GHR and MA-GHBP expression. It was found that GH deficiency was associated with diminished BW, GHR and MA-GHBP expression, while increased GH concentration led to increased BW, GHR and MA-GHBP expression, but MA-GHBP upregulation was more pronounced than the observed increase in GHR expression. Since GHR and MA-GHBP both contribute to liver GH binding capacity, GH-induced enrichment of the dominant negative form would represent a compensatory mechanism triggered by high levels of the hormone. This attempt to attenuate the effects of supraphysiological concentrations of GH may be critical to reduce or prevent their plausible damaging effects on the organism.

Increased SH2-Bbeta content and membrane association in transgenic mice overexpressing GH.

Transgenic mice overexpressing GH present a marked GH signaling desensitization, reflected by low basal phosphorylation levels of the tyrosine kinase JAK2, and signal transducer and activator of transcription-5 (STAT5) and a lack of response of these proteins to a high GH dose. To evaluate the mechanisms involved in the regulation of JAK2 activity by high GH levels in vivo, the content and subcellular distribution of SH2-Bbeta were studied in GH-overexpressing transgenic mice. SH2-B is a member of a conserved family of adapter proteins characterized by the presence of a C-terminal SH2 domain, a central pleckstrin homology (PH) domain, and an N-terminal proline rich region. The isoform SH2-Bbeta modulates JAK2 activity by binding to the phosphorylated enzyme, further increasing its activity. However, it may also interact with non-phosphorylated inactive JAK2 via lower affinity binding sites, preventing abnormal activation of the kinase. SH2-Bbeta may also function as an adapter protein, acting as a GH signaling mediator. We now report that, in an animal model of GH excess in which JAK2 is not phosphorylated, although it is increased in the membrane-fraction, both the level of SH2-Bbeta, and especially its association to membranes, are augmented (67% and 13-fold vs normal mice values respectively), suggesting SH2-Bbeta could modulate JAK2 activity in vivo.

Increased sensitivity to GH in liver of Ames dwarf (Prop1df/Prop1df) mice related to diminished CIS abundance.

To investigate the influence of chronic GH deficiency on GH signaling in vivo, we have analyzed Janus kinase (JAK) 2/signal transducers and activators of transcription (STAT) 5 GH signaling pathway, and its regulation by the suppressors of the cytokine signaling SOCS and by the JAK2-interacting protein SH2-Bbeta, in liver of Ames dwarf (Prop1df/Prop1df) mice, which are severely deficient in GH, prolactin and TSH, and of their normal littermates. Prop1df/Prop1df mice displayed unaltered GH receptor, JAK2 and STAT5a/b protein levels. No significant differences in the basal tyrosine-phosphorylation levels of JAK2 and STAT5a/b were found between both groups of animals. After in vivo administration of a high GH dose (5 microg/g body weight (BW)), the tyrosine-phosphorylation levels of JAK2 and STAT5a/b increased significantly, reaching similar values in normal and dwarf mice. However, after stimulation with lower GH doses (50 and 15 ng/g BW) the tyrosine-phosphorylation level of STAT5a/b was higher in dwarf mice. The protein content of CIS, a SOCS protein that inhibits STAT5 signaling, was approximately 80% lower in dwarf mice liver, while SOCS-2 and SOCS-3 levels were unaltered. The content of SH2-Bbeta, a modulator of JAK2 activity, was reduced by approximately 30% in dwarf mice, although this was associated with normal JAK2 response to a high GH dose. In summary, Prop1df/Prop1df mice display increased hepatic sensitivity to GH, an effect that could be related to the lower abundance of CIS in this tissue. Furthermore, the lower CIS content found in this model of GH deficiency suggests that CIS protein levels are regulated by GH in vivo.

Cytokine-inducible SH2 protein up-regulation is associated with desensitization of GH signaling in GHRH-transgenic mice.

The effects of continuous high GH levels on GH signal transduction through the GH receptor (GHR)/Janus kinase 2 (JAK2)/signal transducer and activator of transcription 5 (STAT5) pathway as well as the desensitization of this pathway by suppressors of cytokine signaling (SOCS) were studied in transgenic mice overexpressing GHRH. In transgenic mice, hepatic GHR levels were 4.5-fold higher than in normal animals, whereas the protein contents of JAK2, STAT5a, and STAT5b did not vary. This same pattern was found for basal tyrosine phosphorylation (PY-): PY-GHR was 4.5-fold increased in transgenic mice, whereas there were no differences in PY-JAK2 and PY-STATs between normal and transgenic animals. After GH administration, tyrosine phosphorylation of GHR, JAK2, and STAT5s increased 3- to 7-fold in normal mice, but no significant changes were found in transgenic mice, indicating a decreased GH sensitivity in these animals. The content of cytokine-inducible SH2 protein, a member of the SOCS family, was 18-fold higher in GHRH-transgenic than in normal mice. Conversely, SOCS-3, present in normal mice, was hardly seen in transgenic animals, whereas SOCS-2 levels did not vary. These findings suggest that cytokine-inducible SH2 protein, significantly induced by continuously elevated GH levels, may be the SOCS protein responsible for the GH signaling desensitization in transgenic animals.

Chemical composition, nutritive value, and toxicology evaluation of Mexican wild lupins.

The nutrient composition, toxic factors content, and nutritional and toxicological value of Lupinus splendens, L. rotundiflorus, L. elegans, L. simulans, L. exaltatus, L. reflexus, and L. madrensis species from Mexico were analyzed. The seeds of these species were a good source of protein. All the species showed a high lysine and tryptophan content, though sulfur amino acids were limiting. Cyanogenic glycosides were absent, and lectins, trypsin inhibitors, and tannins were present in low concentrations. Lupanine was the major alkaloid in almost all the samples, although sparteine was the major alkaloid in Lupinus reflexus (26.63 mg/g of sample). Cytisine was not found in any of the studied lupins. L. reflexus showed the highest acute toxicity, and L. elegans exhibited no toxicity as evaluated using a mice model. The alkaloid was reduced by hot-water extraction. The protein efficiency ratio in water-debittered seeds was relatively poor (1.1-1.5). These results suggest that the wild lupins studied represent a potential protein supply, and they could be domesticated and used for animal feed if the alkaloids were eliminated and the protein was supplemented with methionine, or if the lupins were used in mixture with cereals.

Growth hormone (GH) and estradiol regulation of membrane-associated GH binding protein and GH receptors in GH releasing hormone transgenic mice.

Growth hormone (GH) releasing hormone (GHRH) transgenic mice were used to examine the influence of GH on GH receptor (GHR) and membrane-associated GH binding protein (MA-GHBP) levels by means of specific radioimmunoassays and Western blot analysis, since MA-GHBP was described as the major constituent of somatogenic binding to liver membranes in mice. In transgenic animals, a 10-fold increment over normal values was found for hepatic somatogenic binding that could be accounted for by a 3--4-fold increase in GHR and a 9-fold augmentation of MA-GHBP levels. The apparent molecular weight of MA-GHBP was smaller than that of serum GHBP, a difference that was partially abolished by endoglycosidase F digestion. In vivo treatment of female mice with 17 beta-estradiol led to an unexpected down-regulation of MA-GHBP and GHR by 60--75% only in transgenic animals. MA-GHBP and GHR levels are strongly up-regulated by GH, although MA-GHBP up-regulation is much more important than that of GHR.

[Low cholesterol egg powder. Nutritive and quality characteristics of the product]. / Huevo en polvo con bajo contenido de colesterol. Características nutricias y sanitarias del producto.

The purpose of this study is to obtain a low cholesterol egg powder for the preparation of different foods for persons whose egg consumption is restricted. Egg white and yolk mixtures prepared in different proportions were dehydrated; the following dried mixtures were obtained: A (1:1), B (2:1) and C (3:1) of egg white:yolk respectively. These mixtures were evaluated using the following parameters: proximal analysis, microbiological assay and protein quality evaluation. Physical characteristics of the powder and the sensorial tests of foods prepared with these mixtures were carried out. The fat and the cholesterol content in the mixture C were decreased by 40% and 20% respectively. The microbiological tests showed that the three mixtures were safe for human consumption. The PER of sample A (whole egg) was 3.65 and for the mixture C 3:1 egg white:yolk was 3.05. The PER of the 50:50 protein mixtures eggs white and yolk: with corn lime treated flour (HMN) were higher than that of the casein standard. The sensorial tests of the foods prepared with all the mixtures were acceptable.

High-performance liquid chromatographic determination of the glycoalkaloids alpha-solanine and alpha-chaconine in 12 commercial varieties of Mexican potato.

The glycoalkaloid content in 12 commercial varieties of Mexican potatoes was measured by HPLC in both the peel and the flesh of the potato. The principal glycoalkaloids alpha-solanine and alpha-chaconine were present in higher concentration in the peel than in the flesh of all varieties. The main alkaloid in the peel of the potatoes was alpha-chaconine and comprised about 65-71% of the total glycoalkaloids. The high concentration of alpha-chaconine in peel, which is more toxic than alpha-solanine, gives more protection to the tuber against predators. The total alkaloids in the peel of Alpha, Juanita, Michoacan, Norteña, Rosita, and Tollocan varieties were higher than the limit recommended for food safety. However, the peel represents less than 10% of the total tuber in most of the varieties. The total alkaloids contained in the peel of Atzimba, Lopez, Marciana, Montsama, Murca, and Puebla was lower than the limits recommended for food safety. The glycoalkaloid content in the boiled peeled potatoes was less than 9 mg/100 g but in Alpha, Montsama, and Puebla varieties, both glycoalkaloids were absent. According to the results, the consumption of the 12 commercial varieties of Mexican potatoes does not represent any danger to human health.

Synthesis and study of the cluster [Pd(AuPPh3)6(HgNO3)](NO3) by reversed-phase high-performance liquid chromatography, thermoanalysis, infrared, nuclear magnetic resonance, and fast atom bombardment mass spectrometry.

The addition reaction of Hg0 and Hg(2)2+ to the bimetallic cluster [(PPh3)Pd(AuPPh3)6](NO3)2 (I) has been studied. The reaction, monitored by HPLC, showed the time elapsed to obtain the pure cluster [Pd(AuPPh3)6(HgNO3)](NO3) (II). The use of 31P[1H] NMR, IR spectra, FABMS and thermoanalysis data was very useful for confirming the results. The reaction was monitored by taking five samples after 3, 6, 17, 21 and 24 h. The process was finalised after 24 h and the pure trimetallic cluster II, free of the intermediate, appeared in the chromatogram as a large, unique peak.