59 research outputs found
Non-Slender <i>n</i>-Link Chain Driven by Single-Joint and Multi-Joint Muscle Actuators: Closed-Form Dynamic Equations and Joint Reaction Forces
No full textThe author has derived the closed-form dynamic equations for a planar musculoskeletal chain composed of a generic number n of rigid links connected by ideal revolute joints. Single-joint and multi-joint muscles have been modeled as linear force actuators that can span from one joint to all the joints of the chain. The generic shape and size of each individual link of the chain accounts for different alignments among the center of mass of the link, the centers of rotation of the joints that articulate the link with its neighbors, and the points of application of the muscle forces and the possible contact external resistances acting on the link. The joint torque and the reaction force acting on each joint have been determined in closed-form by analytical quantification of the unique contribution of each individual kinematic and kinetic variable: (1) force of each single-joint or multi-joint muscle spanning or non-spanning the joint; (2) weight and contact external resistances acting on each individual link of the chain; (3) position, angular velocity, and angular acceleration of each individual link of the chain. The analytical results derived in this study can be applied to multilink musculoskeletal chains with deep/superficial and segmental/global muscles
A case of Corynebacterium striatum endocarditis successfully treated with an early switch to oral antimicrobial therapy
No full text: Patients with Corynebacterium striatum endocarditis are usually managed with long-term intravenous antibiotic therapy and hospitalization. Here we describe a case of a 76-year-old woman with hepatitis C virus (HCV) related cirrhosis who developed endocarditis due to Corynebacterium striatum associated with severe aortic regurgitation. To our knowledge, this is the first case to be successfully treated with an early switch to oral linezolid after three weeks of vancomycin. We performed a literature review using the PubMed database and found 27 cases which showed the enhanced virulence of this pathogen especially for long-term hospitalized patients with a frequent need of surgical treatment (44.4%) and long course of parenteral antimicrobial therapy, with vancomycin as drug of choice. There are no studies confirming the possibility of using oral treatment in non-diphtheritic Corynebacteria infective endocarditis. This case report provides us with the evidence that once the patient is in a stable condition, the efficacy and safety of linezolid might be similar to vancomycin administration. New trials and prospective studies are needed to confirm the opportunity of an early switch to oral therapy in this specific setting
Clinical and microbiological characteristics of reactive infectious mucocutaneous eruption: A case series of 5 patients
No full textDaptomycin Pharmacokinetics and Pharmacodynamics in Patients on Methadone Substitution Therapy
No full textBackground and Objective When administered for severe infections in intravenous drug users (IDUs) at a daily dose of 6 mg/kg, daptomycin displayed abnormal pharmacokinetic parameters compared with those seen in healthy volunteers; specifically, decreased trough and maximum concentrations (C-trough; C-max) and increased clearance (CL). The objective of this study was to evaluate the pharmacokinetics and pharmacodynamics of daptomycin administered at a daily dosage of 12 mg/kg for Staphylococcus aureus infective endocarditis (IE) in patients concomitantly treated with methadone, and to compare the results with those published in the literature for healthy controls treated with the same daily dose. Methods Antibiotic treatment included daptomycin (12 mg/kg daily) in combination with an antistaphylococcal beta-lactam (cefazolin 2 g three times a day). The minimum inhibitory concentration (MIC) of Staphylococcus aureus isolated through blood cultures was used to calculate pharmacokinetic and pharmacodynamic parameters such as the ratio of the area under the concentration-time curve over 24 h to the MIC (AUC(0-24)/MIC) and C-max/MIC. Results Five IDUs hospitalized for IE were enrolled. The mean measured daptomycin C-max and C-trough were 54.1 mu g/mL (CV: 0.32) and 8.7 mu g/mL (CV: 0.59), respectively; the mean calculated AUC(0-24) was 742.7 mu g x h/mL (CV: 0.31). The estimated average volume of distribution at the steady state (V-d,V-ss) and the half-life (t(1/2)) were 316.5 mL/kg (CV: 0.53) and 14.4 h (CV: 0.30), respectively. The mean daptomycin clearance from plasma normalized for body weight (CLwp) was 17.3 mL/(h x kg) (CV: 0.33). The calculated average C-max and AUC(0-24) (183.7 mu g/mL and 1277.4 mu g x h/mL, respectively) were lower than and statistically significantly different from (p p = 0.001, respectively) those expected for healthy volunteers. Conclusions Treatment of Staphylococcus aureus IE in IDUs on methadone treatment requires the use of high daptomycin daily doses in order to achieve satisfactory pharmacodynamic parameters. Close monitoring of the daptomycin plasma concentration is suggested
A case of Corynebacterium striatum endocarditis successfully treated with an early switch to oral antimicrobial therapy
No full textPatients with Corynebacterium striatum endocarditis are usually managed with long-term intravenous antibiotic therapy and hospitalization. Here we describe a case of a 76-year-old woman with hepatitis C virus (HCV) related cirrhosis who developed endocarditis due to Corynebacterium striatum associated with severe aortic regurgitation. To our knowledge, this is the first case to be successfully treated with an early switch to oral linezolid after three weeks of vancomycin. We performed a literature review using the PubMed database and found 27 cases which showed the enhanced virulence of this pathogen especially for long-term hospitalized patients with a frequent need of surgical treatment (44.4%) and long course of parenteral antimicrobial therapy, with vancomycin as drug of choice. There are no studies confirming the possibility of using oral treatment in non-diphtheritic Corynebacteria infective endocarditis. This case report provides us with the evidence that once the patient is in a stable condition, the efficacy and safety of linezolid might be similar to vancomycin administration. New trials and prospective studies are needed to confirm the opportunity of an early switch to oral therapy in this specific setting
Customizing Properties of β-Chitin in Squid Pen (Gladius) by Chemical Treatments
No full textThe squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications. - See more at: http://www.mdpi.com/1660-3397/12/12/5979/htm#sthash.7aVdC53H.dpu
The obesity paradox: Analysis from the SMAtteo COvid-19 REgistry (SMACORE) cohort
No full textBackground and aims: Obesity has been suggested as a possible risk factor for a more severe course of COVID-19; however, conclusive evidence is lacking and few studies have investigated the role of BMI as a risk factor for admission to intensive care unit (ICU) and mortality. We retrospectively analyzed a COVID-19 cohort recruited during the first 40 days of the epidemic in Italy. We examined the association between obesity and 30-day mortality, admission to ICU, mortality and length of hospital stay in patients with COVID-19. Methods and results: Demographic, clinical and outcome data were retrospectively analyzed in 331 patients with COVID-19 admitted to hospital between 21 February and 31 March 2020. The predictive effect of obesity on mortality was assessed using a Cox proportional-hazard regression model, its effect on ICU admission and mortality in the ICU using logistic regressions, and its effect on length of hospital stay using a linear regression. Seventy-four of 331 patients had a BMI ≥30 kg/m2. Among obese patients, 21 (28.4%) required admission in ICU and 25 died (33.8%). After controlling for sex, age, comorbidities and clinical data, obesity was not significantly associated with mortality, mortality in ICU and length of hospital stay. The effect of obesity on ICU admission remained significant after controlling for sex, age, interstitial lung disease, heart disease and serum C-reactive protein. Conclusions: Obese patients with COVID-19 were more likely to be admitted to ICU than non-obese patients. However, there were no significant differences in mortality between the two groups
Analysis of hindgut microbiome of sheep and effect of different husbandry conditions
No full textThe microbiome is now seen as an important resource to understand animal health and welfare in many species. However, there are few studies aiming at identifying the association between fecal microbiome composition and husbandry conditions in sheep. A wide range of stressors associated with management and housing of animals increases the hypothalamic–pituitary axis activity, with growing evidence that the microbiome composition can be modified. Therefore, the purpose of the present study was to describe the core microbiome in sheep, characterized using 16S rRNA gene sequencing, and to explore whether exposure to stressful husbandry conditions changed sheep hindgut microbiome composition. Sheep (n = 10) were divided in two groups: isolated group (individually separated for 3 h/day) and control group (housed in the home pen for the entire trial period). Sheep core microbiome was dominated by Firmicutes (43.6%), Bacteroidetes (30.38%), Proteobacteria (10.14%), and Verrucomicrobia (7.55%). Comparative results revealed few operational taxonomic units (OTUs) with significantly different relative abundance between groups. Chao1, abundance-based coverage estimator (ACE), and Fisher’s alpha indices did not show differences between groups. OTU-based Bray–Curtis distances between groups were not significant (p-value = 0.07). In conclusion, these results describing the core microbiome of sheep do not suggest a strong effect of stressful husbandry conditions on microbial composition
Retinoic acid/calcite micro-carriers inserted in fibrin scaffolds modulate neuronal cell differentiation
No full textThe controlled release of cell differentiating agents is crucial in many aspects of regenerative medicine. Here we propose the use of hybrid calcite single crystals as micro-carriers for the controlled and localized release of retinoic acid, which is entrapped within the crystalline lattice. The release of retinoic acid occurs only in the proximity of stem cells, upon dissolution of the calcite hybrid crystals that are dispersed in the fibrin scaffold. These hybrid crystals provide a sustained dosage of the entrapped agent. The environment provided by this composite scaffold enables differentiation towards neuronal cells that form a three-dimensional neuronal network
Customizing Properties of β-Chitin in Squid Pen (Gladius) by Chemical Treatments
No full textThe squid pen (gladius) from the Loligo vulgaris was used for preparation of β-chitin materials characterized by different chemical, micro- and nano-structural properties that preserved, almost completely the macrostructural and the mechanical ones. The β-chitin materials obtained by alkaline treatment showed porosity, wettability and swelling that are a function of the duration of the treatment. Microscopic, spectroscopic and synchrotron X-ray diffraction techniques showed that the chemical environment of the N-acetyl groups of the β-chitin chains changes after the thermal alkaline treatment. As a consequence, the crystalline packing of the β-chitin is modified, due to the intercalation of water molecules between β-chitin sheets. Potential applications of these β-chitin materials range from the nanotechnology to the regenerative medicine. The use of gladii, which are waste products of the fishing industry, has also important environmental implications
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