In vitro and in vivo detection of microbial gene expression in bioactivated scaffolds seeded with cyanobacteria.

Dermal replacement materials bioactivated with cyanobacteria have shown promising potential for wound regeneration. To date, extraction of cyanobacteria RNA from seeded scaffolds has not been described. The aim of this study was to develop a method to isolate total RNA from bioactivated scaffolds and to propose a new approach in determining living bacteria based on real-time PCR. Transgenic Synechococcus sp. PCC 7002 (tSyn7002) were seeded in liquid cultures or scaffolds for dermal regeneration in vitro and in vivo for 7 days. RNA was extracted with a 260/280 ratio of ≥2. The small subunit of the 30S ribosome in prokaryotes (16S) and RNAse P protein (rnpA) were validated as reference transcripts for PCR analysis. Gene expression patterns differed in vitro and in vivo. Expression of 16S was significantly upregulated in scaffolds in vitro, as compared to liquid cultures, whilst rnpA expression was comparable. In vivo, both 16S and rnpA showed reduced expression compared to in vitro (16S: in vivo Ct value 13.21 ± 0.32, in vitro 12.44 ± 0.42; rnpA in vivo Ct value 19.87 ± 0.41, in vitro 17.75 ± 1.41). Overall, the results demonstrate rnpA and 16S expression after 7 days of implantation in vitro and in vivo, proving the presence of living bacteria embedded in scaffolds using qPCR.

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.

Recomendación Clínica: "Recomendaciones para el manejo de pacientes con COVID-19 con indicación terapéutica de ventilación mecánica que eventualmente son conectados a máquinas de anestesia" / Recommendations for patient management with COVID-19 with therapeutic indication mechanical ventilation that eventually are connected to anesthesia machines

La pandemia de COVID-19 producida por SARS-CoV-2 actualmente en curso anticipa una gran demanda por ventiladores mecánicos (VM), ya que un porcentaje relevante de los contagiados cae rápidamente en insuficiencia respiratoria y requiere de cuidados intensivos. Anticipándose a ese exceso de demanda y considerando que es muy probable que el número actual de ventiladores mecánicos en las unidades de cuidados intensivos (UCI) sean insuficientes, se ha solicitado a la SACH un informe técnico en relación al uso de las máquinas de anestesia como VM.

Recomendaciones para el manejo de pacientes con COVID19 en el perioperatorio / Recommendations for the management of patients with COVID19 in the perioperative period

En diciembre de 2019, una serie de casos de neumonía de causa desconocida surgieron en Wuhan, Hubei, China, con presentaciones clínicas muy parecidas a la neumonía viral. El análisis de secuenciación profunda de muestras del tracto respiratorio inferior indicó un nuevo coronavirus, que se denominó nuevo coronavirus 2019 (2019-nCoV o SARS-CoV2) [15]. La propagación del virus ha sido extremadamente rápida, tanto así que el 11 de marzo de 2020 y luego de más de 118.000 infectados en 114 países con 4.300 fallecidos a esa fecha, la organización mundial de la salud declaró a la enfermedad COVID-19, causada por 2019-nCoV, como una pandemia.

Acute stimulation of mesenchymal stem cells with cigarette smoke extract affects their migration, differentiation, and paracrine potential.

Mesenchymal stem cells (MSCs) are known to play a key role in tissue regeneration, while smoking cigarettes is described to impair it. This work focuses on the effect cigarette smoke extract (CSE) has on the migration, differentiation, and paracrine potential of human adipose derived MSCs (AdMSCs). To mimic native conditions in vitro, AdMSCs were cultured in either monolayer or three-dimensional pellet cultures. While constant exposure to high concentrations of CSE had lethal effects on AdMSCs, lower concentrations of CSE impaired cell migration when compared to control conditions. The secretion of key interleukins was downregulated when CSE was exposed to the cells at low concentrations. Moreover, in this work AdMSCs were exposed to CSE while simultaneously being induced to differentiate into adipocytes, osteoblasts, and chondrocytes to determine the effect of CSE on the cells potential to differentiate. While adipogenic differentiation showed no significant variation, AdMSCs exposed to osteogenic and chondrogenic supplements showed both early and late genetic level variation when acutely exposed to low concentrations of CSE. Our results indicate that even a small amount of cigarette smoke can have detrimental effects on the regenerative potential of MSCs.

The influence of pancreas-derived stem cells on scaffold based skin regeneration.

It has been shown that Pancreatic Stem Cells (PSCs) share many features with skin stem cells. Yet, their potential role in skin regeneration remains to be elucidated. 5x10(5) PSCs from male Rattus norwegicus were seeded on Matriderm scaffold overnight. Cells survival and proliferation were then tested in vitro showing the survival of the cells and their homogenous distribution in the scaffolds. Afterwards, scaffolds were used to replace bilateral full-thickness skin wounds made on the dorsum of Nu/Nu mice. A control group of nude mice received the Matriderm scaffolds without cells. Two weeks after transplantation, wound areas were harvested and analyzed with respect to epithelialization, vascularization and wound closure. The healing area and regeneration rate were significantly increased in the group used the PSCs-seeded scaffolds (factor of 2.1). Vascularization rate showed a significant increase in the PSCs-seeded scaffolds(factor of 1.5). Morphology and immunohistochemistry showed new skin-like structures positive to epidermal markers in the healing wound bed. PSCs were detected in the regenerated tissues. This study showed that the combined use of PSCs with the Matriderm as a scaffold for dermal regeneration significantly increased the epidermalization, vascularization and healing in full-thickness wounds.

Use of Erythropoietin as adjuvant therapy in nerve reconstruction.

BACKGROUND AND AIMS: Adjuvant therapies may improve the outcome after nerve reconstruction. We analyzed the influence of recombinant human Erythropoietin (rHuEpo), which has proven angiogenic and neuroprotective effects, on the quality of peripheral nerve regeneration. METHODS: Thirty two female Lewis rats underwent nerve reconstruction by means of tubulization (groups I and II) or autologous sciatic nerve grafting (groups III and IV). Groups I and III received daily subcutaneous rHuEpo injections over 2 weeks (1,000 U/kg bw) with normal saline injections as controls (groups II and IV). Data on histology and muscle weight were collected after 7 weeks. Axon count and diameter were assessed by a new method based on digital segmentation. RESULTS: Atrophy of the tibial muscle was less severe in the rHuEpo-treated group compared to controls resulting in significant higher muscle weight quotients (p = 0.006). The same trend was found in the gastrocnemius muscle, but without being statistically significant. No significant differences in axon count or axon diameter were detected in the presence of rHuEpo treatments. CONCLUSION: Our findings give evidence for a positive effect of Erythropoietin on functional recovery after nerve grafting. Muscle recovery benefited from rHuEpo administration despite absence of improved neural morphology. Semi-automated axon detection facilitated accurate morphometrical assessment.

Observations on the failure of stent-grafts in the aortic arch.

INTRODUCTION: The results of endovascular stent-grafts in the abdominal aorta and descending thoracic aorta have been encouraging. Expanding the use of thoracic stent-grafts in to the aortic arch has been associated with increasing numbers of complications. Recently isolated cases of stent-graft collapse have been reported. METHODS: This was a multi-centre European case series. Data was collected retrospectively on seven patients from five experienced endovascular centres with thoracic stent-graft collapse. RESULTS: Of the seven patients four were treated for traumatic aortic rupture. Six were male, median age 33 (range 17-54) years. During the ensuing 2 months all patients suffered stent-graft collapse. This was symptomatic in 3 patients and the rest were identified on CT. Endovascular management was possible in 6/7 patients using either a balloon expandable stent (n=6) or further stent-graft (n=1). Two patients had persistent type I endoleak despite treatment. Two of the 7 patients died, both of which presented with symptomatic thoracic stent-graft occlusion. Both deaths were a direct result of stent-graft collapse. CONCLUSIONS: Thoracic stent-graft collapse may be asymptomatic underscoring the importance of stent-graft surveillance. Endovascular management of collapse is possible in most cases using a large balloon expandable stent. Symptomatic collapse is associated with high morbidity and mortality.

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo.

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Odor response properties of neighboring mitral/tufted cells in the rat olfactory bulb.

Olfactory perception initiates in the nasal epithelium wherefrom olfactory receptor neurons--expressing the same receptor protein--project and converge in two different glomeruli within each olfactory bulb. Recent evidence suggests that glomeruli are isolated functional units, arranged in a chemotopic manner in the olfactory bulb. Exposure to odorants leads to the activation of specific populations of glomeruli. In rodents, about 25-50 mitral/tufted cells project their primary dendrites to a single glomerulus receiving similar sensory input. Yet, little is known about the properties of neighboring mitral/tufted cells connected to one or a few neighboring glomeruli. We used tetrodes to simultaneously record multiple single-unit activity in the mitral cell layer of anesthetized, freely breathing rats while exposed to mixtures of chemically related compounds. First, we characterized the odorant-induced modifications in firing rate of neighboring mitral/tufted cells and found that they do not share odorant response profiles. Individual units showed a long silent (11.01 ms) period with no oscillatory activity. Cross-correlation analysis between neighboring mitral/tufted cells revealed negligible synchronous activity among them. Finally, we show that respiratory-related temporal patterns are dissimilar among neighboring mitral/tufted cells and also that odorant stimulation results in an individual modification that is not necessarily shared by neighboring mitral/tufted cells. These results show that neighboring mitral/tufted cells frequently exhibit dissimilar response properties, which are not consistent with a precise chemotopic map at the mitral/tufted cell layer in the olfactory bulb.

First-generation aortic endografts: analysis of explanted Stentor devices from the EUROSTAR Registry.

PURPOSE: To examine the structure and healing characteristics of chronically implanted Stentor endografts that were explanted due to migration, endoleak, thrombosis, or aneurysm expansion. METHODS: The devices were harvested following reoperation (n = 5) or autopsy (n = 1) with implantation times ranging from 13 to 53 months. Structural modifications to the metal components were examined using radiography, endoscopy, and magnetic resonance imaging (MRI). Specimens taken from components of the modular stent-grafts were examined histologically and with scanning electron microscopy (SEM) to assess healing behavior. Physical and chemical stability of the nitinol wires and woven polyester graft material was evaluated using SEM and electron spectroscopy for chemical analysis. RESULTS: Although the endografts were retrieved for a variety of reasons, they exhibited similar healing and structural modifications. The woven polyester sleeve showed evidence of yarn shifting and distortion, yarn damage, and filament breakage leading to the formation of openings in the fabric. The luminal surface endografts showed incomplete healing characterized by a poorly organized, nonadherent thrombotic matrix of variable thickness. Radiographic and endoscopic observations indicated that structural failure of the grafts, particularly in the main aortic component, was related to severe compaction and dislocation of the metallic frame due to suture breaks. Corrosion marks were observed on some nitinol wires in all devices. Chemical analysis and ion bombardment of the nitinol wires revealed that the surface concentrations of titanium and nickel were not homogenous. The first layer was composed of carbon or organic elements, followed by a stratum of highly oxidized titanium with a low nickel concentration; the titanium-nickel alloy lay beneath these layers. CONCLUSIONS: Although the materials selected for construction of endovascular grafts appears judicious, the assembly of these biomaterials into various interrelated structures within the device requires further improvement.

Treatment of popliteal artery aneurysms with uncovered Wallstents.

We report two patients with acutely thrombosed popliteal artery aneurysms that were successfully treated with a combination of thrombolytic therapy and placement of noncovered Wallstents.

[Endovascular treatment of abdominal aorta aneurysms using bifurcated endoprosthesis]. / Tratamiento endovascular de los aneurismas de aorta abdominal con endoprótesis bifurcadas.

OBJECTIVE: To obtain an initial assessment of the implantation technique of bifurcated vascular endoprothesis in the treatment of abdominal aorta aneurysms (AAA). METHODS: Eleven Vanguard type endoprostheses were implanted in eleven patients with infra-renal aortic aneurysm. The technique was performed with surgical approach in one femoral artery, and percutaneously in the other. The procedure was performed with epidural anesthesia. RESULTS: A technical success--i.e., the exclusion of the aneurysm--was obtained in all cases. No technical complications occurred during the procedure. Three patients had low degree contrast leak in the angiographic control immediately after the procedure. Eight patients had low grade fever in the immediate follow-up which resolved with medical therapy, two patients had hematomas in the approach sites, one renal infarction, one ileus for two days, another one for five days, and three patients had lymphatic effusion. During follow-up the patients with leak had to undergo co-axial endoprosthesis implantation. CONCLUSIONS: It is our view that bifurcated vascular endoprostheses offer a valid alternative in the treatment of AAA. The procedure can be performed with epidural anesthesia and sedation, with a low rate of complications. The long term follow-up and the perfecting of the approach and resection systems will ultimately dictate their usefulness in this and other vascular conditions.

[Arteriovenous malformation of the superior mesenteric artery with secondary portal hypertension]. / Malformación arteriovenosa de la mesentérica superior con hiperaflujo e hipertensión portal secundaria.

The case of a 60-year-old patient who was repeatedly admitted for ascitic decompensation secondary to hyperflow portal hypertension provoked by congenital arteriovenous malformation of the superior mesenteric artery is presented. Diagnosis was performed by arteriography. Surgical treatment was conducted with total resection of the malformation thereby achieving complete resolution and normalization of portal pressure. The literature is reviewed and the pathophysiologic mechanism as well as the clinical manifestations, diagnosis and treatment are discussed.

Sweet lupin protein quality in young men.

The protein quality of Lupinus albus cv Multolupa was evaluated in young adult males using the nitrogen balance technique at graded levels of N intake, and compared with egg protein. Lupin protein was consumed at levels of 0.4, 0.6 and 0.8 g/(kg.d) and egg protein at 0.3, 0.45 and 0.6 g/(kg.d). Each period started with 1 d of consuming a protein-free diet; the next 6 d were used as adaptation and the last 4 d for balance. The levels of protein intake were randomly assigned by a modified Latin square. Energy intake was individually adjusted. Mean apparent N digestibility values of lupin protein were 78.8, 76.1 and 70.2% for the levels of 0.8, 0.6 and 0.4 g protein(kg.d), respectively, and 83.8, 78.3 and 67.1% for egg protein consumed at levels of 0.6, 0.45 and 0.3 g protein/(kg.d), respectively. The N balance results obtained when subjects consumed lupin were 16.4, 0.2 and -15.1 mg N/(kg.d) for protein intakes of 0.8, 0.6 and 0.4 g/(kg.d), respectively. Those obtained for egg consumption were 12.6, -3.6 and -17.1 mg N/(kg.d) for protein intakes of 0.6, 0.45 and 0.3 g/(kg.d), respectively. The linear regressions of intake and absorbed N to retained N for lupin were: N retained = -43.41 + 0.50 N intake and N retained = -36.30 + 0.53 N absorbed. The corresponding regressions for egg were: N retained = -45.0 + 0.65 N intake and N retained = -30.65 + 0.58 N absorbed. The net protein utilization of lupin was 77% that of egg protein.

[The effect of extrusion on the acceptability and digestibility of diets for growing dogs]. / Efecto de la extrusión sobre la aceptabilidad y digestibilidad de dietas para perros en crecimiento.

Eight German Shepherd pups, about 75 days old and a live weight of 11 kg at the beginning of the trial, were used to assay a diet formulated according to NRC, 1985 (Nutrient Requirements of Dogs). The diet was administered either pelletized (PD) or extruded (ED). Acceptability was evaluated through a cafeteria test, and diet utilization by a digestion trial, wherein dry matter (DM), crude protein (CP), ether extract (EE), crude fiber (CF), nitrogen-free extract (NFE), energy (E), Ca and P were considered. At the beginning and at the end of the digestibility trial, venous blood samples were obtained to run biochemical profiles. Results of the cafeteria test showed that extrusion-cooking improved significantly (P greater than 0.01) diet consumption, which for the ED was 512 and for the PD, 253 g/animal/day. Extrusion also improved significantly (P less than 0.01), the digestibility of DM, CP, EE, NFE and E, reaching values of 82.6, 75.2, 83.9, 90.8 and 83.6% for ED, and 68.0, 64.6, 76.7, 73.5 and 69.7 for PD, respectively. For CF, Ca and P, there was no effect (P greater than 0.05) of extrusion over digestibility. The biochemical profiles, only exhibited minor changes, all figures being considered within the normal range for puppies. It is concluded that extrusion-cooking significantly improves acceptability and biological utilization of normal diets for dogs.

Popliteal artery and venous aneurysm as a complication of arthroscopic meniscectomy.

A 29-year-old man presented a 2-week history of right popliteal fossa and leg swelling following an arthroscopic meniscectomy. Roentgenographic evaluation showed an arterial and venous aneurysm at the popliteal level, with an associated arteriovenous fistula. Popliteal aneurysm in young men is very rare and generally related to open surgical techniques; incidence with arthroscopic techniques is extremely infrequent.

[Plasma zinc and copper in infants with protein-calorie malnutrition]. / Zinc y cobre plasmáticos en lactantes con desnutrición proteínico-energética.

Forty-five marasmic infants were studied for plasma zinc and copper levels. They were selected from those children admitted to a nutritional recovery center. The mean plasma zinc level was 92.4 +/- 24 micrograms/dl (mean +/- SD); 7% of the infants had low zinc values as defined by zinc less than 70 micrograms/dl. Median copper was 90 micrograms/dl (range 27-172) and 49% of the children had copper levels below 90 micrograms/dl (established as our normal limit). Birth weight, breast feeding and prior hospitalization for acute diarrhea with dehydration were studied as antecedents related to low Cu and Zn. Children with prior diagnosis of acute diarrhea and hospitalization had lower copper levels than those sent from primary care centers. Breast feeding was associated with higher Cu levels. No relationship was found between zinc levels and those antecedents, but differences were found in regard to the degree of malnutrition, season of the year and Zn status. In this investigation no Zn deficiency was found in marasmus cases. Hypocupremia, however, is a very significant problem in marasmic infants, especially when associated with early weaning and the presence of previous hospitalization for acute diarrhea.