Dynamic behavior of a spring-powered micronozzle needle-free injector

Conventional injection is still the leading method to deliver macromolecular therapeutics. Needle injection is considered a low compliance administration strategy, principally due to pain and needle phobia. This has fostered the research on the development of alternative strategies to circumvent the skin barrier. Among needle-free drug delivery methods, jet injection is an old strategy with great potential not yet completely disclosed. Here, the design, engineering and dynamic behavior of a novel spring-powered micronozzle needle-free injector is presented. Fluid mechanics was first studied in air to calculate jet force and speed as well as injection duration in different conditions. Polyacrylamide gel was used to simulate a soft tissue and to investigate the jet evolution over time of different injected doses. Finally, ex vivo characterization was carried out on pig skin. Results evidenced a direct dependence of the force, velocity, and duration with the injection volume. The model material allowed individuating the different steps of jet penetration and to attempt a mechanistic explanation. A different behavior has been recorded in the skin with interesting findings for subcutaneous and/or dermal delivery. Peculiar features with respect to existing jet injectors confers to this device good potentiality for a future clinical application.

In vitro and in vivo toxicity evaluation of plant virus nanocarriers

The use of biological self-assembling materials, plant virus nanoparticles in particular, appears very intriguing as it allows a great choice of symmetries and dimensions, easy chemical and biological engineering of both surface and/or internal cavity as well as safe and rapid production in plants. In this perspective, we present an initial evaluation of the safety profile of two structurally different plant viruses produced in Nicotiana benthamiana L. plants: the filamentous Potato virus X and the icosahedral Tomato bushy stunt virus. In vitro haemolysis assay was used to test the cytotoxic effects, which could arise by pVNPs interaction with cellular membranes, while early embryo assay was used to evaluate toxicity and teratogenicity in vivo. Data indicates that these structurally robust particles, still able to infect plants after incubation in serum up to 24h, have neither toxic nor teratogenic effects in vitro and in vivo. This work represents the first safety-focused characterization of pVNPs in view of their possible use as drug delivery carriers.

[Hospital-based internal medicine: year 2011 in chief resident's perspective]

The year 2011 was full of significant advances in all areas of medicine. Whether small or large issues, they all have an impact on daily practice in general internal medicine. For example, intravenous administration of diuretics in heart failure shows no benefit. But double dose may improve symptoms faster. Direct Xa inhibitors are emerging as alternative to anti-vitamin K. beta-blockers reduce overall mortality in COPD and do not worsen lung function significantly. Each year, the chief residents from the Department of internal medicine at the University hospital of Lausanne meet to share their readings. Twelve new therapeutic considerations of 2011 are reviewed here.

[An experimental model for assessing the risk factors for work-related stress in four Italian universities]

This study, a collaborative effort among the Local Health Authority 2 of Perugia, Italy, the National Coordination of Worker's Safety Representatives for University and Research Institutions and the National Coordination for Protection and Prevention Services for Universities and Research Institutions, describes the results of a method used to evaluate work-related stress. Personnel from four Italian universities, which we call University I, II, III and IV geographically distributed in nord (1), center (2) and south (1) of Italy, responded to a questionnaire regarding risk evaluation of work-related stress in response to the Italian Law 81/2008. The methodology includes a preliminary analysis of the physical/technological and organizational/relational aspects of the company in order to determine a risk factor of work-related stress. This is followed by an evaluation by agencies competent in the areas of prevention and protection, (Administrative personnel of the company, Medical support persons, heads of the Prevention and Protection Service, employee representatives, and others) that apply a specific algorithm and by the employees through the completion of a questionnaire. The employees, mostly men, of the various universities, completed 510 questionnaires. Based on the results of the questionnaires and on a comparison between the expectations of the administration and the employees, the preventative measures that need to be adopted were identified. The results of this study show that there is not complete agreement between the administration and the employees regarding the work-related expectations. This difference in viewpoints could be a source of work-related stress. Some aspects of the study were shown to be of common concern in the various universities, while for other aspects, there were significantly different perceptions between male and female employees. An immediate response is needed with respect to some aspects in the work context and to plan further investigations where the results are not clear. The method used provides an adequate response to the legislative requirements and labor principles, in evaluating the risk of work related stress. In addition the method allows employees to contribute directly to the evaluation process.

Biochemical activity and multiple locations of particulate guanylate cyclase in Rhyacophila dorsalis acutidens (Insecta: Trichoptera) provide insights into the cGMP signalling pathway in Malpighian tubules

In insect renal physiology, cGMP and cAMP have important regulatory roles. In Drosophila melanogaster, considered a good model for molecular physiology studies, and in other insects, cGMP and cAMP act as signalling molecules in the Malpighian tubules (MTs). However, many questions related to cyclic nucleotide functions are unsolved in principal cells (PC) and stellate cells (SC), the two cell types that compose the MT. In PC, despite the large body of information available on soluble guanylate cyclase (sGC) in the cGMP pathway, the functional circuit of particulate guanylate cyclase (pGC) remains obscure. In SC, on the other side, the synthesis and physiological role of the cGMP are still unknown. Our biochemical data regarding the presence of cyclic nucleotides in the MTs of Rhyacophila dorsalis acutidens revealed a cGMP level above the 50%, in comparison with the cAMP. The specific activity values for the membrane-bound guanylate cyclase were also recorded, implying that, besides the sGC, pGC is a physiologically relevant source of cGMP in MTs. Cytochemical studies showed ultrastructurally that there was a great deal of pGC on the basolateral membranes of both the principal and stellate cells. In addition, pGC was also detected in the contact zone between the two cell types and in the apical microvillar region of the stellate cells bordering the tubule lumen. The pGC signal is so well represented in PC and, unexpectedly in SC of MTs, that it is possible to hypothesize the existence of still uncharacterized physiological processes regulated by the pGC-cGMP system.

Metabolomics: the "new clinical chemistry" for personalized neonatal medicine

Metabolomics is a new approach based on the systematic study of the full complement of metabolites in a biological sample. This technology consists of two sequential steps: (1) an experimental technique, based on mass spectrometry or nuclear magnetic resonance (NMR) spectroscopy, designed to profile low molecular weight compounds, and (2) multivariate data analysis. Metabolomic analysis of biofluids or tissues has been successfully used in the fields of physiology, diagnostics, functional genomics, pharmacology, toxicology and nutrition. Recent studies have evaluated how physiological variables or pathological conditions can affect metabolomic profiles of different biofluids in pediatric populations. Little is known about the overall metabolic status of the term and preterm neonate. On the other hand, the management of sick or preterm newborns might be improved if more information on perinatal/neonatal maturational processes and their metabolic background were available. At present, the use of metabolomics in Neonatology is still in the pioneering phase. Meaningful diagnostic information and simple, non-invasive collection techniques make urine a particularly suitable biofluid for metabolomic approach in neonatal medicine. Using NMR-based metabolomic analysis of urine, distinct metabolic patterns have been shown to be associated with different classes of gestational age in a population of preterm and term infants. Together with genomics and proteomics, metabolomics appears to be a promising tool in Neonatology for the monitoring of postnatal metabolic maturation, the identification of biomarkers as early predictors of outcome, the diagnosis and monitoring of various diseases and the "tailored" management of neonatal disorders.

Vagal nerve stimulation improves cerebellar tremor and dysphagia in multiple sclerosis

Vagus nerve stimulation (VNS), an adjunctive approach for the treatment of epilepsy, was performed in three multiple sclerosis (MS) patients displaying postural cerebellar tremor (PCT) and dysphagia. Following VNS, improvement of PCT and dysphagia was manifested over a period of two and three months, respectively. In view of the involvement of the main brainstem visceral component of the vagus, the nucleus tractus solitarius (NTS), in modulating central pattern generators (CPGs) linked to both olive complex pathway and swallowing, improvement is likely to be VNS related. The results obtained suggest an additional therapeutic application for VNS and may represent a novel form of treatment in patients with severe MS.

A novel Cx32 mutation causes X-linked Charcot-Marie-Tooth disease with brainstem involvement and brain magnetic resonance spectroscopy abnormalities

The objective of this study was to study genetic and phenotypic features of a family with X-linked Charcot-Marie-Tooth consisting of a healthy father, affected mother, two affected sons and one healthy one. A detailed electrophysiological and neuroimaging study, along with sequencing of the Cx32 gene, was performed in all family members. A novel Cx32 123 G>C mutation, determining an aminoacid variation (Glu41Asp), was found in the mother and the affected sons. An alteration in brainstem evoked potentials was found in the mother and one affected son. The affected son, who underwent magnetic resonance imaging, showed symmetrical hyperintensities in paratrigonal white matter, not found in his heterozygous mother, while both subjects exhibited alterations in brain metabolite ratios derived from localised proton-magnetic resonance spectroscopy. These data extend previous findings about central nervous system involvement in Cx32 mutated subjects and further support a functional role of the protein expression in oligodendrocytes.

Increase in 20–50Hz (gamma frequencies) power spectrum and synchronization after chronic vagal nerve stimulation

OBJECTIVE

Though vagus nerve stimulation (VNS) is an important option in pharmaco-resistant epilepsy, its mechanism of action remains unclear. The observation that VNS desynchronised the EEG activity in animals suggested that this mechanism could be involved in VNS antiepileptic effects in humans. Indeed VNS decreases spiking bursts, whereas its effects on the EEG background remain uncertain. The objective of the present study is to investigate how VNS affects local and inter regional syncronization in different frequencies in pharmaco-resistant partial epilepsy.

METHODS

Digital recordings acquired in 11 epileptic subjects 1 year and 1 week before VNS surgery were compared with that obtained 1 month and 1 year after VNS activation. Power spectrum and synchronization were then analyzed and compared with an epileptic group of 10 patients treated with AEDs only.

RESULTS

VNS decreases the synchronization of theta frequencies (P < 0.01), whereas it increases gamma power spectrum and synchronization (< 0.001 and 0.01, respectively).

CONCLUSIONS

The reduction of theta frequencies and the increase in power spectrum and synchronization of gamma bands can be related to VNS anticonvulsant mechanism. In addition, gamma modulation could also play a seizure-independent role in improving attentional performances.

SIGNIFICANCE

These results suggest that some antiepileptic mechanisms affected by VNS can be modulated by or be the reflection of EEG changes.

Localization of acid phosphatases in the cell fractions of chick liver

3 molecular forms (P1, P2 and P3) of acid phosphatase (E.C. 3.1.3.2) have been detected in chicken liver homogenate. The different intracellular localization of these molecules has been demonstrated by cellular fractionation and electrophoretic analysis. P1 and P2 phosphatases are both present in the particulate fraction. P3 is present in a pure form in the soluble fraction. The difference between the enzyme molecules present in the particulate fraction and that in the soluble one is confirmed by the different activation-inhibition effect of various ions and substances on the enzymatic activity of subcellular fractions.

Acid and alkaline phosphatase heterogeneity in liver, heart and intestine of the adult chick

The molecular heterogeneity of acid and alkaline phosphatase from chick liver, intestine and heart is demonstrated by polyacrilamide disc gel electrophoresis. Liver and heart show the same number of molecular forms of acid and alkaline phosphatases. In contrast, the intestine homogenate shows electrophoretic bands different in number and in gel position from those of the liver and of the heart.