Procalcitonin and C-reactive protein as early markers of postoperative intra-abdominal infection in patients operated on colorectal cancer.

PURPOSE: The aim of this study was to evaluate the accuracy of serum procalcitonin (PCT) and C-reactive protein (CRP) for early diagnosis of postoperative intra-abdominal infections (PIAI) after elective surgery for colorectal cancer. METHODS: Prospective observational study including patients operated on for colorectal cancer between January and December of 2015 was performed. Serum PCT and CRP levels were measured before surgery and daily until postoperative day 3. RESULTS: One hundred twenty patients were included. Seven patients (5.8%) had PIAI. PCT levels were significantly higher in patients with PIAI on postoperative days 1 and 3, whereas CRP levels only were significantly more elevated on postoperative day 3. The ratio between CRP levels on postoperative day 3 and CRP levels on postoperative days 2 (CRP D3/CRP D2) and 1 (CRP D3/CRP D1) was significantly higher in patients with PIAI. PCT on postoperative day 3, for a cutoff of 0.45 ng/mL, had the best sensitivity (100%) with a specificity of 73.8%. The ratio CRP D3/CRP D1 yielded the higher specificity and positive predictive value (90.9 and 27.3%, respectively, for a cutoff of 1.8). The higher negative predictive value was obtained for PCT on postoperative days 1 and 3 (100%, with cutoff of 0.76 and 0.45 ng/mL, respectively) and for CRP on postoperative day 3 (100% with cutoff of 10 mg/dL). CONCLUSION: PCT and CRP serum levels are associated with the appearance of PIAI after colorectal cancer surgery, although the positive predictive values were low for both PCT and CRP. However, the negative predictive values were high.

[Compliance with the PECARN and AEP guidelines in diagnostic approach of mild head trauma in patients younger than 24 months old]. / Adecuación del manejo diagnóstico del traumatismo craneoencefálico leve en menores de 24 meses a las guías de práctica clínica de PECARN y AEP.

INTRODUCTION: Mild head trauma is a frequent complaint in Pediatric Emergency Departments. Several guidelines have been published in the last few years. However, significant variability can be appreciated in terms of the demand for image tests. The aim of this study is to determine the level of compliance with PECARN and AEP guidelines in the management of patients younger than 24 months old in four different hospitals. PATIENTS AND METHODS: A multicenter retrospective study was conducted on patients presenting with mild head trauma between October 1st, 2011 and March 31st, 2013 in the Emergency Departments of four hospitals. RESULTS: In the analysis of the results obtained, only one of the four hospitals complied with the AEP guidelines in more than 50% of the patients. The other three hospitals had a level of compliance lower than 50%. Management was more suitable according to PECARN guidelines, with 3 of the 4 hospitals having a level of compliance greater than 50%. However, the best compliance achieved by a hospital was only of 70%. CONCLUSIONS: The study shows that the level of compliance with guidelines for management of mild head trauma in patients younger than 24 months old is low.

Estrogen replacement improves spatial reference memory and increases hippocampal synaptophysin in aged female mice.

Estrogen deficiency during menopause is often associated with memory dysfunction. However, inconsistencies regarding the ability of estrogen to improve memory in menopausal women highlight the need to evaluate, in a controlled animal model, the potential for estrogen to alleviate age-related mnemonic decline. The current study tested whether estrogen could ameliorate spatial reference memory decline in aged female mice. At the conclusion of testing, levels of the presynaptic protein synaptophysin, and activities of the synthetic enzymes for acetylcholine and GABA, were measured in the hippocampus and neocortex. Aged (27-28-month-old) female C57BL/6 mice were given daily subcutaneous injections of 1 microg or 5 microg of beta-estradiol-3-benzoate dissolved in sesame oil. Control mice received daily injections of sesame oil or no injections. Estradiol treatment began 5 days prior to behavioral testing and continued throughout testing. Spatial and non-spatial memory were assessed in the Morris water maze. The 5 microg dose of estradiol significantly improved spatial learning and memory in aged females. The performance of 5 microg females improved significantly more rapidly than that of control females; estradiol-treated females performed at asymptotic levels by session 2. Furthermore, 5 microg females exhibited a more robust spatial bias than controls during probe trials. In contrast, 1 microg of estradiol did not improve spatial task performance. Neither dose affected performance of the non-spatial task. In the hippocampus, synaptophysin was increased in 5 microg females relative to controls. Estrogen did not affect enzyme activities in either brain region. This study is the first to examine the effects of estrogen replacement on spatial reference memory and synaptophysin expression in aged post-estropausal female rodents. The results suggest that: (1) estrogen can profoundly improve spatial reference memory in aged females, and (2) this improvement may be related to increased hippocampal synaptic plasticity, but not modulation of the synthetic enzymes for acetylcholine and GABA.

Farnesyl diphosphate synthase. Altering the catalytic site to select for geranyl diphosphate activity.

Farnesyl diphosphate synthase (FPPase) catalyzes chain elongation of the C(5) substrate dimethylallyl diphosphate (DMAPP) to the C(15) product farnesyl diphosphate (FPP) by addition of two molecules of isopentenyl diphosphate (IPP). The synthesis of FPP proceeds in two steps, where the C(10) product of the first addition, geranyl diphosphate (GPP), is the substrate for the second addition. The product selectivity of avian FPPase was altered to favor synthesis of GPP by site-directed mutagenesis of residues that form the binding pocket for the hydrocarbon residue of the allylic substrate. Amino acid substitutions that reduced the size of the binding pocket were identified by molecular modeling. FPPase mutants containing seven promising modifications were constructed. Initial screens using DMAPP and GPP as substrates indicated that two of the substitutions, A116W and N144'W, strongly discriminated against binding of GPP to the allylic site. These observations were confirmed by an analysis of the products from reactions with DMAPP in the presence of excess IPP and by comparing the steady-state kinetic constants for the wild-type enzyme and the A116W and N114W mutants.

Infecciones hospitalarias en las unidades de cuidados intensivos / Hospital infections in intensive care units

Se presentan los resultados de un estudio de infecciones hospitalarias (IHS) realizado en 4 unidades de cuidados intensivos del Hospital de Pediatría Juan P. Garrahan en 1995. El objetivo fue conocer algunas variables epidemiológicas relacionadas con las infecciones hospitalarias. Para el estudio se utilizó la metodología del National Nosocomial Infection Surveillance (NNIS) de EStados Unidos, que analiza las tasas específicas de infección teniendo en cuenta el número de pacientes días con procedimientos que significan riesgo de infección. Se determinaron las tasas de neumonías sobre pacientes días con asistencia respiratoria mecánica (ARM), la de bacteriemias sobre pacientes días con catéter central (CC) e infecciones urinarias sobre pacientes días con catéter vesical (CV). En el caso de neonatología se analizaron por separado las tasas de los niños con peso al nacer de menos de 1500 gramos y de 1500 gramos o más. Las tasas de neumonías oscilaron entre 3.8 y 9.7 por 1000 días de ARM; las de bacteriemias entre 2.7 y 7.9 por 1000 días de CC; las de infección urinaria entre 3.4 y 10.7 por 1000 días de CV. Estas cifras son semejantes a los promedios de los servicios de NNIS. Al analizar las tasas de IH por meses se advierten grandes variaciones; los picos corresponden generalmente a brotes de distintas patologías. En la Unidad de Cuidados Intensivos Neonatales se aprecia que los niños nacidos con menos de 1500 gramos tienen tasas de IH superiores a los nacidos con mayor peso. Se analizan especialmente los microorganismos productores de las IHS en cada localización y unidad, advirtiéndose en este rubro diferencias muy marcadas con el estudios de Estados Unidos. Se concluye que es importante que cada institución y aún cada servicio analice por separados sus tasas de IH para poder llevar a cabo procedimientos de prevención que tengan base epidemiológica.

Dynamics and topographical distribution of surface glycoproteins during myoblast fusion: a resonance energy transfer study.

We have investigated changes in topography and lateral translational mobility of concanavalin A (Con A) receptors on the surface of cultured chick muscle cells during the period of myoblast fusion. A temporal correlation between these phenomena and the alteration in membrane fluidity known to occur during this time period is established. Receptor topography and mobility are studied by means of a resonance energy transfer technique employing pyrene- and FITC-Con A conjugates. All measurements are performed through a microscope on single cells. Our results reveal that during the period of myoblast fusion Con A receptors undergo a dramatic redistribution on the cell surface. Furthermore, our data suggest that the changes in membrane fluidity observed during muscle differentiation serve to modulate the lateral mobility of these receptors.

Changes in membrane dynamics associated with myogenic cell fusion.

Changes in membrane dynamic properties associated with membrane fusion are studied employing in vitro myoblast fusion as a model system. We utilize a microscopic fluorescence relaxation approach which makes feasible the study of local variations in membrane dynamics within surface subdomains of single intact cells. Studies of the average rotational mobility of the fluorescent probe-1-anilino-naphthalene-8-sulfonate by this technique indicate that myoblast fusion activity is preceded by a generalized increased in membrane fluidity and that areas of cell contact between fusing cells exhibit higher fluidity and polarity, locally, than non-fusion regions.

Cell surface distribution of lectin receptors determined by resonance energy transfer.

The surface topography of concanavalin A (con A) bound to normal and transformed murine fibroblasts has been studied by a new technique involving fluorescence resonance energy transfer (RET), RET can provide a high resolution "map" of the distances separating con A-receptor complexes in single living cells. The distribution of con A is non-random in both normal and transformed cells, but sites are more closely approximated in the transformed. Approximation is induced by the con A but occurs at extremely slow rates indicating that the topography is not primarily determined by simple diffusion of complexes.

Fluidity of natural membranes and phosphatidylserine and ganglioside dispersions. Effect of local anesthetics, cholesterol and protein.

The microviscosity of artificial lipid membranes and natural membranes was measured by the fluorescence polarization technique employing perylene as the probe. Lipid dispersions composed of brain gangliosides exhibited greater microviscosity than phosphatidylserine (268 cP vs 173 cP, at 25 degrees C). Incorporation of cholesterol (30-50%) increased the microviscosity of lipid phases by 200-500 cP. Cholesterol's effect on membrane fluidity was completely reversed by digitonin but not by amphotericin B. Incorporation of membrane proteins into lipid vesicles gave varying results. Cytochrome b5 did not alter membrane fluidity. However, myelin proteolipid produced an apparent increase in microviscosity, but this effect might be due to partitioning of perylene between lipid and protein binding sites since tha latter have a higher fluorescence anisotropy than the lipid. The local anesthetics tetracain and butacaine increased the fluidity of lipid dispersions, natural membranes and intact ascites tumor cell membranes. The effect of anesthetics appears to be due to an increased disordering of lipid structure. The fluidity of natural membranes at 25 degrees C varied as follows: polymorphonuclear leukocytes, 335 cP; bovine brain myelin, 270 cP; human erythrocyte, 180 cP; rat liver microsomes, 95 cP; rat liver mitochondria, 90 cP. In most cases the microviscosity of natural membranes reflects their cholesterol: phospholipid ratio. The natural variations in fluidity of cellular membranes probably reflect important functional requirements. Similarly, the effects of some drugs which alter membrane permeability may be the result of their effects on membrane fluidity.