A data-driven model for COVID-19 pandemic - Evolution of the attack rate and prognosis for Brazil.

We introduce a compartmental model SEIAHRV (Susceptible, Exposed, Infected, Asymptomatic, Hospitalized, Recovered, Vaccinated) with age structure for the spread of the SARAS-CoV virus. In order to model current different vaccines we use compartments for individuals vaccinated with one and two doses without vaccine failure and a compartment for vaccinated individual with vaccine failure. The model allows to consider any number of different vaccines with different efficacies and delays between doses. Contacts among age groups are modeled by a contact matrix and the contagion matrix is obtained from a probability of contagion p c per contact. The model uses known epidemiological parameters and the time dependent probability p c is obtained by fitting the model output to the series of deaths in each locality, and reflects non-pharmaceutical interventions. As a benchmark the output of the model is compared to two good quality serological surveys, and applied to study the evolution of the COVID-19 pandemic in the main Brazilian cities with a total population of more than one million. We also discuss with some detail the case of the city of Manaus which raised special attention due to a previous report of We also estimate the attack rate, the total proportion of cases (symptomatic and asymptomatic) with respect to the total population, for all Brazilian states since the beginning of the COVID-19 pandemic. We argue that the model present here is relevant to assessing present policies not only in Brazil but also in any place where good serological surveys are not available.

Anti-botulism single-shot vaccine using chitosan for protein encapsulation by simple coacervation

The aim of the present study was to compare the potency and safety of vaccines against Clostridium botulinum (C. botulinum) type C and D formulated with chitosan as controlled release matrix and vaccines formulated in conventional manner using aluminum hydroxide. Parameters were established for the development of chitosan microspheres, using simple coacervation to standardize the use of this polymer in protein encapsulation for vaccine formulation. To formulate a single shot vaccine inactivated antigens of C botulinum type C and D were used with original toxin titles equal to 5.2 and 6.2 log LD50/ml, respectively. For each antigen a chitosan based solution of 50 mL was prepared. Control vaccines were formulated by mixing toxoid type C and D with aluminum hydroxide [25% Al(OH)(3), pH 6.3]. The toxoid sterility, innocuity and potency of vaccines were evaluated as stipulated by MAPA-BRASIL according to ministerial directive no. 23. Encapsulation efficiency of BSA in chitosan was 32.5-40.37%, while that the encapsulation efficiency to toxoid type C was 41,03% (1.94 mg/mL) and of the toxoid type D was 32.30% (1.82 mg/mL). The single shot vaccine formulated using chitosan for protein encapsulation through simple coacervation showed potency and safety similar to conventional vaccine currently used in Brazilian livestock (10 and 2 IU/mL against C botulinum type C and D, respectively). The present work suggests that our single shot vaccine would be a good option as a cattle vaccine against these C botulinum type C and D.

Transtracheal puncture: a forgotten procedure

Transtracheal puncture has long been known as a safe, low-cost procedure. However, with the advent of bronchoscopy, it has largely been forgotten. Two researchers have suggested the use of α-amylase activity to diagnose salivary aspiration, but the normal values of this enzyme in tracheobronchial secretions are unknown. We aimed to define the normal values of α-amylase activity in tracheobronchial secretions and verify the rate of major complications of transtracheal puncture. From October 2009 to June 2011, we prospectively evaluated 118 patients without clinical or radiological signs of salivary aspiration who underwent transtracheal puncture before bronchoscopy. The patients were sedated with a solution of lidocaine and diazepam until they reached a Ramsay sedation score of 2 or 3. We then cleaned the cervical region and anesthetized the superficial planes with lidocaine. Next, we injected 10 mL of 2% lidocaine into the tracheobronchial tree. Finally, we injected 10 mL of normal saline into the tracheobronchial tree and immediately aspirated the saline with maximum vacuum pressure to collect samples for measurement of the α-amylase level. The α-amylase level mean ± SE, median, and range were 1914 ± 240, 1056, and 24-10,000 IU/L, respectively. No major complications (peripheral desaturation, subcutaneous emphysema, cardiac arrhythmia, or hemoptysis) occurred among 118 patients who underwent this procedure. Transtracheal aspiration is a safe, low-cost procedure. We herein define for the first time the normal α-amylase levels in the tracheobronchial secretions of humans.

Enhanced nonsynaptic epileptiform activity in the dentate gyrus after kainate-induced status epilepticus.

Understanding the mechanisms that influence brain excitability and synchronization provides hope that epileptic seizures can be controlled. In this scenario, non-synaptic mechanisms have a critical role in seizure activity. The contribution of ion transporters to the regulation of seizure-like activity has not been extensively studied. Here, we examined how non-synaptic epileptiform activity (NEA) in the CA1 and dentate gyrus (DG) regions of the hippocampal formation were affected by kainic acid (KA) administration. NEA enhancement in the DG and suppression in area CA1 were associated with increased NKCC1 expression in neurons and severe neuronal loss accompanied by marked glial proliferation, respectively. Twenty-four hours after KA, the DG exhibited intense microglial activation that was associated with reduced cell density in the infra-pyramidal lamina; however, cellular density recovered 7 days after KA. Intense Ki67 immunoreactivity was observed in the subgranular proliferative zone of the DG, which indicates new neuron incorporation into the granule layer. In addition, bumetanide, a selective inhibitor of neuronal Cl(-) uptake mediated by NKCC1, was used to confirm that the NKCC1 increase effectively contributed to NEA changes in the DG. Furthermore, 7 days after KA, prominent NKCC1 staining was identified in the axon initial segments of granule cells, at the exact site where action potentials are preferentially initiated, which endowed these neurons with increased excitability. Taken together, our data suggest a key role of NKCC1 in NEA in the DG.

Avaliação da atividade antibacteriana do óleo essencial de Lippia origanoides frente à Staphylococcus sp. isolados de alimentos de origem animal / Assessment of the antibacterial activity of the essential oil of Lippia origanoides in relation to Staphylococcus sp. isolated from food of animal origin

Objetivou-se no trabalho avaliar a ação antibacteriana do óleo essencial de Lippia origanoides frente à isolados de Staphylococcus sp. de alimentos de origem animal. Para tanto, realizou-se análise química da composição do óleo, teste de sensibilidade das bactérias frente a dez antibióticos de uso terapêutico e ao óleo essencial de Lippia origanoides, além da determinação da concentração inibitória mínima (CIM) e da concentração bactericida mínima (CBM). A análise cromatográfica do óleo apresentou o timol como composto majoritário (48,70%), além de pequena quantidade de carvacrol (1,14%). No teste de sensibilidade frente aos antibióticos, 75% dos isolados apresentaram resistência a, no mínimo, três antibióticos. Em relação ao óleo essencial, os isolados de Staphylococcus sp oriundos de leite bovino mostraram-se mais resistentes e os isolados de carne ovina apresentaram-se mais sensíveis. A CIM foi maior para os Staphylococcus sp. isolados de leite bovino e leite ovino (60µL/mL). Enquanto que para os isolados de carcaça de ovinos e queijo, a CIM foi de 15µL/mL e 30µL/mL respectivamente. A CBM, consequentemente, foi maior para os isolados de leite bovino e leite ovino, sendo de 240µL/mL e 120µL/mL respectivamente. O óleo essencial de Lippia origanoides apresenta atividade antimicrobiana sobre Staphylococcus sp. isolados de alimentos.

The aim of this study was to evaluate the antibacterial activity of the essential oil of Lippia origanoides in relation to Staphylococcus sp. isolated from food of animal origin. For this purpose, we performed the chemical analysis to determine the oil composition, evaluated the bacteria sensibility to ten antibiotics of therapeutic use and determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The chromatographic analysis showed that tymol was the main compound (48.70%) and that carvacrol was present in a small amount (1.14%). In the test of antibiotic susceptibility, 75% of the microorganism isolates were resistant to at least three of the ten antibiotics tested. The Staphylococcus sp isolated from bovine milk was more resistant to the essential oil of Lippia origanoides, and the microorganism isolated from sheep meat was more susceptible to this oil. The Staphylococcus sp. isolated from bovine or sheep milk showed a MIC of 60µL/mL and for those isolated from sheep carcass and cheese the MIC was 15µL/mL and 30µL/mL, respectively. Consequently, the MBC was higher for isolates from cow's (240µL/mL) and sheep's milk (120µL/mL) when compared with other food sources. These results suggest that the essential oil of Lippia origanoides has antimicrobial activity against staphylococcus sp. isolated from food.