COVA1-18 neutralizing antibody protects against SARS-CoV-2 in three preclinical models.

One year into the Coronavirus Disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2), effective treatments are still needed 1-3 . Monoclonal antibodies, given alone or as part of a therapeutic cocktail, have shown promising results in patients, raising the hope that they could play an important role in preventing clinical deterioration in severely ill or in exposed, high risk individuals 4-6 . Here, we evaluated the prophylactic and therapeutic effect of COVA1-18 in vivo , a neutralizing antibody isolated from a convalescent patient 7 and highly potent against the B.1.1.7. isolate 8,9 . In both prophylactic and therapeutic settings, SARS-CoV-2 remained undetectable in the lungs of COVA1-18 treated hACE2 mice. Therapeutic treatment also caused a dramatic reduction in viral loads in the lungs of Syrian hamsters. When administered at 10 mg kg - 1 one day prior to a high dose SARS-CoV-2 challenge in cynomolgus macaques, COVA1-18 had a very strong antiviral activity in the upper respiratory compartments with an estimated reduction in viral infectivity of more than 95%, and prevented lymphopenia and extensive lung lesions. Modelling and experimental findings demonstrate that COVA1-18 has a strong antiviral activity in three different preclinical models and could be a valuable candidate for further clinical evaluation.

Permanence time in the herd and milk production of Holstein cows with up to five successive extended lactations.

A total of 1338 high-yielding cows with five lactations from a large well-managed commercial dairy operation in a hot environment of northern Mexico were used to evaluate milk yield and reproductive performance of cows undergoing unplanned extended lactations (EL; > 450 days). The null hypothesis that cumulative milk yield during five consecutive lactations is the same in cows not having unplanned EL and cows with several EL was tested. All EL resulted from cows failing to become pregnant with ≥ 4 services. Cows were allocated to 1 of 6 groups according to the number of EL (EL0 for cows with no EL to EL5 for cows with 5 EL). Cumulative milk yield was highest (P < 0.01) for EL5 cows (95,499 kg) and lowest for EL0 cows (56,236 kg). Likewise, cumulative days in milk were greatest (P < 0.01) in EL5 (2968 days) and lowest in EL0 (1857 days) cows. Mean milk yield per lactation increased linearly with the increase in the number of extended lactations with a maximum of 19,099 kg of milk/lactation for EL5 cows. Mean daily milk yield/productive life was lowest (P < 0.01) for EL0 (30.2 kg) and highest for EL5 (32.1 kg). The percentage of days in milk relative to days from birth to the end of the fifth lactation was highest for EL5 (78.1%) and lowest for EL0 (59.6%), with EL2 to EL4 cows intermediate. Length of calving interval was longest (P < 0.01) for EL5 (24.7 months) and shortest for EL0 (15.5 months) cows. It was concluded that it is worthwhile maintaining high-yielding cows incapable to conceive before 230 days in milk because they did conceive again and produced considerable amounts of milk during their productive life, which substantially prolonged their permanence time in the herd.

Factors influencing English Bulldog bitch fertility after surgical uterine deposition of fresh semen.

The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P4) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500 × 106) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (P < 0.05) in bitches with >23 kg than bitches with <23 kg (83.9 vs 63.8%). Whelping rate was greater (P < 0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (P < 0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4 mL or >4 mL of semen). Litter size was larger (P < 0.05) in bitches >23 kg than lighter animals (3.72 ±â€¯1.79 and 2.30 ±â€¯1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P4 concentration and infusion of oxytocin in the uterus at AI (P > 0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4 mL semen volume maximize whelping rates in this breed of dogs.

Differential frontal alpha oscillations and mechanisms underlying loss of consciousness: a comparison between slow and fast propofol infusion rates.

Mechanisms underlying loss of consciousness following propofol administration remain incompletely understood. The objective of this study was to compare frontal lobe electroencephalography activity and brainstem reflexes during intravenous induction of general anaesthesia, in patients receiving a typical bolus dose (fast infusion) of propofol compared with a slower infusion rate. We sought to determine whether brainstem suppression ('bottom-up') predominates over loss of cortical function ('top-down'). Sixteen ASA physical status-1 patients were randomly assigned to either a fast or slow propofol infusion group. Loss of consciousness and brainstem reflexes were assessed every 30 s by a neurologist blinded to treatment allocation. We performed a multitaper spectral analysis of all electroencephalography data obtained from each participant. Brainstem reflexes were present in all eight patients in the slow infusion group, while being absent in all patients in the fast infusion group, at the moment of loss of consciousness (p = 0.010). An increase in alpha band power was observed before loss of consciousness only in participants allocated to the slow infusion group. Alpha band power emerged several minutes after the loss of consciousness in participants allocated to the fast infusion group. Our results show a predominance of 'bottom-up' mechanisms during fast infusion rates and 'top-down' mechanisms during slow infusion rates. The underlying mechanisms by which propofol induces loss of consciousness are potentially influenced by the speed of infusion.

Analysis of radioprotection and antimutagenic effects of Ilex paraguariensis infusion and its component rutin.

DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.

Dexmedetomidine metabolic clearance is not affected by fat mass in obese patients.

BACKGROUND: Obesity has been associated with reduced dexmedetomidine clearance, suggesting impaired hepatic function or reduced hepatic blood flow. The aim of this study was to clarify the effect of obesity in dexmedetomidine metabolic clearance. METHODS: Forty patients, ASA I-III, 18-60 yr old, weighing 47-126 kg, scheduled for abdominal laparoscopic surgery, were enrolled. Anaesthetic agents (propofol, remifentanil, and dexmedetomidine) were dosed based on lean body weight measured by dual X-ray absorptiometry. Serial venous samples were drawn during and after dexmedetomidine infusion. A pharmacokinetic analysis was undertaken using non-linear mixed-effect models. In the modelling approach, the total body weight, lean body weight, and adjusted body weight were first tested as size descriptors for volumes and clearances. Hepatic blood flow, liver histopathology, liver enzymes, and gene expression of metabolic enzymes (UGT2B10 and UGT1A4) were tested as covariates of dexmedetomidine metabolic clearance. A decrease in NONMEM objective function value (ΔOFV) of 3.84 points, for an added parameter, was considered significant at the 0.05 level. RESULTS: A total of 637 dexmedetomidine serum samples were obtained. A two-compartmental model scaled to measured lean weight adequately described the dexmedetomidine pharmacokinetics. Liver blood flow was a covariate for dexmedetomidine clearance (ΔOFV=-5.878). Other factors, including fat mass, histopathological damage, and differential expression of enzymes, did not affect the dexmedetomidine clearance in the population studied (ΔOFV<3.84). CONCLUSIONS: We did not find a negative influence of obesity in dexmedetomidine clearance when doses were adjusted to lean body weight. Liver blood flow showed a significant effect on dexmedetomidine clearance. CLINICAL TRIAL REGISTRATION: NCT02557867.

Analysis of radioprotection and antimutagenic effects of Ilex paraguariensis infusion and its component rutin

DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.

Association of polymorphisms in growth hormone and leptin candidate genes with live weight traits of Brahman cattle.

Polymorphisms in candidate genes can produce significant and favorable changes in the phenotype, and therefore are useful for the identification of the best combination of favorable variants for marker-assisted selection. In the present study, an assessment to evaluate the effect of 11 single nucleotide polymorphisms (SNPs) in candidate genes on live weight traits of registered Brahman cattle was performed. Data from purebred bulls were used in this assessment. The dataset included birth (BW), weaning (WW), and yearling (YW) weights. A panel of 11 SNP markers, selected by their formerly reported or apparent direct and indirect association with live weight traits, was included in an assessment previously confirming their minimum allele frequency (<0.05). Live weights were adjusted BW (aBW), WW (aWW), and YW (aYW) using a generalized linear model, which included the fixed effects of herd and season of birth and the random effect of the sire and year of birth. An SNP in a growth hormone gene (GH4.1) was significantly related to aWW (P = 0.035) with an estimate substitution effect of 3.97 kg (P = 0.0210). In addition, a leptin SNP (LEPg.978) was significantly associated with aYW (P = 0.003) with an estimate substitution effect of 9.57 kg (P = 0.0007). The results suggest that markers GH4.1 and LEPg.978 can be considered as candidate loci for assisted genetic improvement programs in Mexican Brahman cattle.

Post-operative cognitive dysfunction at 3 months in adults after non-cardiac surgery: a qualitative systematic review.

BACKGROUND: Post-operative cognitive dysfunction is defined as a decline in cognitive functions that occurs after surgery, but different diagnostic criteria and incidences have been reported in medical literature. Our aim was to determine incidence of post-operative cognitive dysfunction 3 months after non-cardiac surgery in adults. METHODS: A systematic review of available evidence was performed by PRISMA guidelines. A search was done in May-July 2015 on PubMed, EMBASE, CINAHL, LILACS, Scielo, Clinical Trials, and Grey Literature Reports. Inclusion criteria were prospective design studies with patients over 18 years old, surgery under general or regional anesthesia, follow-up for 3 months, and use of a neurocognitive battery for diagnosis. We excluded studies made on cardiac or brain surgery patients. Risk of bias was assessed using tools from National Heart Lung and Blood Institute. RESULTS: We selected 24 studies. Average age was 68 years. Only five studies reported incidence of cognitive decline for a non-surgical control group. Median number of tests used was 5 (range 3-13). Pooled incidence of post-operative cognitive dysfunction at 3 months was 11.7% [95% CI 10.9-12.5] but with several methodological differences between studies. Increasing age was the most consistent risk factor identified (seven studies). CONCLUSIONS: Post-operative cognitive dysfunction in patients is frequent, especially in patients over 60 years old. Limitations include methodological differences in studies. Efforts must be made to reach a consensus in definition and diagnosis for future research.

Prematuros tardíos: estudio clínico retrospectivo de sus causas y consecuencias / Late preterm infants: a retrospective clinical study of their causes and consequences

ANTECEDENTES: Los niños nacidos entre las 34 0/7 y 36 6/7 semanas se denominan prematuros tardíos (PT), constituyen 5-7% de los nacidos y poseen mayor morbimortalidad que los niños de término. OBJETIVO: Analizar las causas de partos PT en nuestra institución. Comparar morbilidad neonatal de nacidos PT y de término. MÉTODOS: Estudio de cohorte retrospectivo. Se revisan registros de nacimientos entre enero de 2009 y diciembre de 2012 identificando los nacidos vivos entre las 34 0/7 y 36 6/7 y entre las 39 0/6 y 40 6/7 semanas. Se identifica grupo clínico de parto prematuro al que pertenecen. Se compara frecuencia de resultados perinatales de nacidos PT y de término completo. RESULTADOS: En el período estudiado nacieron 8.890 niños vivos. Tasa de partos PT fue 7,49% (n = 666). El 64,11% fue por causa idiopática o asociado a rotura de membranas y 35,89% por indicación médica. Dentro del grupo de indicaciones médicas un 19,25% de interrupciones no están basadas en evidencia y ninguna puramente electiva. Los PT, comparados con niños de término, tienen más riesgo de hospitalización y morbilidad neonatal; este riesgo es mayor a menor edad gestacional. CONCLUSIONES: En nuestro hospital 1 de cada 5 PT pudo haber nacido a una edad gestacional mayor, lo que podría haber evitado los riesgos perinatales asociados. Se sugiere que las instituciones de salud analicen las causas de interrupciones del embarazo en el grupo de PT, lo que podría ser un indicador de calidad obstétrica.

BACKGROUND: Children born between 34 0/7 and 36 6/7 weeks of gestation are called late-preterm infants. Represent 5 to 7% of live births and they are at higher risk of morbidity and mortality than term infants. OBJECTIVE: To analyze causes of late preterm births in our institution. To compare neonatal morbidity in late-preterm and term infants. METHODS: A retrospective cohort study. Birth records between January 2009 and December 2012 were reviewed identifying live births between 34 0/7 and 36 6/7 and between 39 0/6 and 40 6/7 weeks of gestation. Clinical group of preterm labor to which they belong was identified. Frequency of perinatal outcomes of late-preterm and term infants were compared. RESULTS: In the period under study there were 8890 live birth. The late-preterm birth rate was 7.49% (n = 666); 64.11% of them was idiopathic in cause or associated with rupture of membranes and 35.89% was for medical indication. In the group of medical indications 19.25% of the interruptions were not based on evidence and none were purely elective. Late-preterm infants have higher risk of hospitalization and neonatal morbidity than term infants; this risk is higher at earlier gestational ages. CONCLUSIONS: In our hospital 1 in 5 late-preterm birth could have been born at higher gestational age, preventing perinatal risks. It is suggested that health institutions analyze causes of interruption of pregnancy in the late-preterm group, which could constitute an indicator of obstetric quality.

Rhabdomyolysis after initial session of indoor cycling: analysis of 11 patients.

AIM: The aim of this paper was to highlight the special frequency of cases of rhabdomyolysis related to the practice of indoor cycling and to define the characteristics, course, and outcome of this disease. METHODS: Retrospective review of clinical histories of patients diagnosed with rhabdomyolysis after indoor cycling in our unit from January 2012 to April 2013. RESULTS: Eleven patients were analyzed. All patients, regardless of the degree of previous physical training, were diagnosed after a first session of indoor cycling. Mean age was 27.63 years (SD=5.74). Fifty-four percent were women. Creatine kinase (CK) levels gradually decreased in response to rest and intensive intravenous hydration. Only in two cases was renal failure observed, and in none were electrolyte disorders, disseminated intravascular coagulation (DIC) or compartmental syndrome detected. CONCLUSION: A first session of indoor cycling has become a common cause of rhabdomyolysis secondary to the physical exercise in recent years, which should alert those responsible for teaching this sport of the need for a gradual start under adequate hydration and environmental conditions, because although the condition has a benign course with adequate treatment and the complication rate is low, there are patients with increased susceptibility to very high CK blood levels requiring hospitalization for treatment and follow-up of possible complications.

Double-pulse and calibration-free laser-induced breakdown spectroscopy at low-ablative energies.

The use of double-pulse laser-induced breakdown spectroscopy (DP-LIBS) in quantitative analysis generally depends on standards and calibration curves. To our knowledge, in this Letter, we report the first quantitative analysis based on DP-LIBS at low ablative energies with a self-calibrated method. We compare the effects of plasmas on the calibration-free LIBS technique, generated by DP-LIBS, and the traditional single-pulse (SP) LIBS on a steel sample. Our analyses reveal that when SP-LIBS and DP-LIBS reach comparable emission line intensities, plasma parameters and quantitative analysis are practically the same for both experiments. Additionally, we report the behavior of the emission enhancement of some elements (Fe and Cr) at low ablative pulse energies (0.2-8 mJ) using the orthogonal reheating DP-LIBS configuration.

[Cross-sectional study of deviated nasal septum in unilaterally operated fissures]. / Estudio transversal de la desviación del tabique nasal en las fisuras unilaterales operadas.

INTRODUCTION: Nasal septum deviation is one the most significant nasal deformities among cleft and lip patients and its anatomical variations along the anterior-posterior axis within the nasal cavity has not been specified. AIM: To define whether there are differences in the degree of nasal septum deviation between the anterior, middle and posterior areas of the nasal cavity in operated unilateral cleft lip and palate patients. MATERIAL AND METHOD: Twenty-nine unilateral complete cleft lip and palate patients, between 5 and 17 years, attending San Borja Arriarán Hospital and the University of Chile's School of Dentistry were included. The nasal septum deviation index was measured at different depths across the anteroposterior axis by cone-beam computed tomography. A random effects model was performed for data analysis. RESULTS: The nasal septum deviation index presented differences between the three planes studied. The plane with lesser deviation was the anterior, while the plane with greater deviation was the posterior. These differences resulted statistically significant (P < 0.05). CONCLUSION: In complete unilateral cleft and lip patients mainly the posterior part of the nasal septum should be corrected, because there is a greater deviation in that area.

Estudio transversal de la desviación del tabique nasal en las fi suras unilaterales operadas / Fertility survey of patients opened on of cryptorchidism in the pediatric age

Introducción. La desviación del tabique nasal es una de las deformaciones nasales más significativas entre los pacientes fisurados unilaterales y sus variaciones anatómicas dentro de la cavidad nasal no han sido del todo precisadas en relación al eje antero-posterior Objetivo. Determinar si existen diferencias en el grado de desviación del tabique nasal entre las zonas anterior, media y posterior de la cavidad nasal, en pacientes operados de fi sura-labio-máxilo-palatina unilateral. Material y método. Veintinueve pacientes operados de fi sura labiomáxilo-palatina unilateral entre 5 y 17 años, controlados en el Hospital San Borja Arriarán y Facultad de Odontología de la Universidad de Chile fueron incluidos. El coeficiente de desviación del tabique nasal fue medido a distintas profundidades a lo largo del eje antero-posterior mediante tomografía computarizada de haz cónico, y comparado utilizando un programa para estimar modelos de efectos aleatorios. Resultados. El coeficiente de desviación del tabique nasal presentó diferencias entre los tres planos estudiados. El plano con menor desviación fue el anterior, mientras que el plano con la mayor desviación fue el posterior. Estas diferencias resultaron estadísticamente significativas (P<0,05).Conclusiones. Durante la corrección quirúrgica del tabique nasal de los pacientes portadores de fi sura unilateral completa se debe prestar mayor atención a la porción posterior de esta estructura, ya que se encuentra más comprometida por la deformidad (AU)

Introduction. Nasal septum deviation is one the most significant nasal deformities among cleft and lip patients and its anatomical variations along the anterior-posterior axis within the nasal cavity has not been specified.Aim. To defi ne whether there are differences in the degree of nasal septum deviation between the anterior, middle and posterior areas of the nasal cavity in operated unilateral cleft lip and palate patients. Material and method. Twenty-nine unilateral complete cleft lip and palate patients, between 5 and 17 years, attending San Borja Arriarán Hospital and the University of Chile’s School of Dentistry were included. The nasal septum deviation index was measured at different depths across the anteroposterior axis by cone-beam computed tomography. A random effects model was performed for data analysis. Results. The nasal septum deviation index presented differences between the three planes studied. The plane with lesser deviation was the anterior, while the plane with greater deviation was the posterior. These differences resulted statistically significant (P<0.05).Conclusion. In complete unilateral cleft and lip patients mainly the posterior part of the nasal septum should be corrected, because there is a greater deviation in that area (AU)

Recent advances on Ilex paraguariensis research: minireview.

Ilex paraguariensis dried and minced leaves are made into a brewed tea, prepared in a sui generis manner by large populations in South America, having evolved from a tea drunk by the Guarani ethnic group to a beverage that has a social and almost ritualistic role in some South American modern societies. It is used both as a source of caffeine, in lieu or in parallel with tea and coffee, but also as a therapeutic agent for its alleged pharmacological properties. Although with some exceptions, research on biomedical properties of this herb has had a late start and strongly lags behind the impressive amount of literature on green tea and coffee. However, in the past 15 years, there was a several-fold increase in the literature studying Ilex paraguariensis properties showing effects such as antioxidant properties in chemical models and ex vivo lipoprotein studies, vaso-dilating and lipid reduction properties, antimutagenic effects, controversial association with oropharyngeal cancer, anti-glycation effects and weight reduction properties. Lately, promising results from human intervention studies have surfaced and the literature offers several developments on this area. The aim of this review is to provide a concise summary of the research published in the past three years, with an emphasis on translational studies, inflammation and lipid metabolism. Ilex paraguariensis reduces LDL-cholesterol levels in humans with Ilex paraguariensis dyslipoproteinemia and the effect is synergic with that of statins. Plasma antioxidant capacity as well as expression of antioxidant enzymes is positively modulated by intervention with Ilex paraguariensis in human cohorts. A review on the evidence implicating Ilex paraguariensis heavy consumption with some neoplasias show data that are inconclusive but indicate that contamination with alkylating agents during the drying process of the leaves should be avoided. On the other hand, several new studies confirm the antimutagenic effects of Ilex paraguariensis in different models, from DNA double breaks in cell culture models to mice studies. Novel interesting work has emerged showing significant effect on weight reduction both in mice and in rat models. Some mechanisms involved are inhibition of pancreatic lipase, activation of AMPK and uncoupling of electron transport. Intervention studies in animals have provided strong evidence of anti-inflammatory effects of Ilex paraguariensis, notably protecting cigarette-induced lung inflammation acting on macrophage migration and inactivating matrix-metalloproteinase. Research on the effects of Ilex paraguariensis in health and disease has confirmed its antioxidant, anti-inflammatory, antimutagenic and lipid-lowering activities. Although we are still waiting for the double-blind, randomized prospective clinical trial, the evidence seems to provide support for beneficial effects of mate drinking on chronic diseases with inflammatory component and lipid metabolism disorders.

Hallazgos tomográficos pulmonares y su asociación con niveles de linfocitos T CD4+ en pacientes portadores del virus de inmunodeficiencia humana / CT pulmonary findings and their association with CD4+ T lymphocytes levels in human immunodeficiency virus carriers

Respiratory diseases are frequent complications in HIV infection. High Resolution Computed Tomography (HRCT) has proven superior to conventional imaging techniques to establish a pulmonary disease diagnosis. A study was conducted in order to establish the association between tomographic pulmonary patterns and immune status of HIV-infected patients. We evaluated 35 patients with respiratory symptoms and / or abnormal chest radiograph. An association was observed between the presence of ground glass pattern and P jirovecii infection. Likewise, a correlation between pulmonary histoplasmosis diagnosis and honeycomb pattern, lung cysts and nodules was established. Few correlation between tomographic patterns and CD4 + T lymphocyte counts was observed. In summary, HRCT findings can predict certain types of infection; nevertheless, further studies are required to extrapolate this association to other noninfectious lung diseases in HIV-infected patients.

Las enfermedades respiratorias constituyen complicaciones frecuentes en la infección por VIH. La Tomografía Axial Computarizada de Alta Resolución (TACAR) ha demostrado ser superior a las técnicas de imagen convencionales para establecer diagnóstico de enfermedad pulmonar. Se realizó un estudio con la finalidad de establecer la asociación entre patrones tomográficos pulmonares y el estado inmunológico de pacientes VIH+. Se evaluaron 35 pacientes sintomáticos respiratorios y/o con radiografía torácica patológica. Se observó una asociación entre la presencia de patrón en vidrio esmerilado e infección por P jirovecii. Asimismo, se observó una asociación entre diagnóstico de histoplasmosis pulmonar y patrón de panal de abejas, quistes pulmonares y nódulos. Se demostraron pocas correlaciones entre patrones tomográficos y conteo de linfocitos T CD4+. En conclusión, los hallazgos en la TACAR pueden predecir determinados tipos de infección requiriendo de más estudios para extrapolar esta asociación a otras enfermedades pulmonares no infecciosas en el paciente VIH+.

Morphological, rheological and mechanical characterization of polypropylene nanocomposite blends.

In the present work, the effectiveness of styrene/ethylene-butylene/styrene rubbers grafted with maleic anhydride (MA) and a metallocene polyethylene (mPE) as toughening materials in binary and ternary blends with polypropylene and its nanocomposite as continuous phases was evaluated in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), oscillatory shear flow and dynamic mechanical thermal analysis (DMA). The flexural modulus and heat distortion temperature values were determined as well. A metallocene polyethylene and a polyamide-6 were used as dispersed phases in these binary and ternary blends produced via melt blending in a corotating twin-screw extruder. Results showed that the compatibilized blends prepared without clay are tougher than those prepared with the nanocomposite of PP as the matrix phase and no significant changes in shear viscosity, melt elasticity, flexural or storage moduli and heat distortion temperature values were observed between them. However, the binary blend with a nanocomposite of PP as matrix and metallocene polyethylene phase exhibited better toughness, lower shear viscosity, flexural modulus, and heat distortion temperature values than that prepared with polyamide-6 as dispersed phase. These results are related to the degree of clay dispersion in the PP and to the type of morphology developed in the different blends.