32 research outputs found
How Can We Improve the Delivery of Urology Teaching to Medical Students Using Modern Educational Techniques?
No full textFortis Gaba,1 Qassi Q Gaba,2 Dilini A Fernando3 1University of Edinburgh Medical School, University of Edinburgh, Edinburgh, UK; 2Department of Medical Sciences, University of Oxford, Oxford, UK; 3Ninewells Hospital and Medical School, University of Dundee, Dundee, UKCorrespondence: Fortis Gaba, University of Edinburgh Medical School, University of Edinburgh, 47 Little France Cres, Edinburgh, EH16 4TJ, UK, Tel +447783985984, Email [email protected]: It is generally well-known that the medical school curriculum is becoming increasingly busy, more so with the COVID-19 pandemic. By itself, urology education will need to adapt to meet the changing circumstances, but it remains uncertain on how best to address this need. In this article, we will discuss several methods that will allow institutions to ease and overcome pressures using modern educational techniques. These methods can be classified based on the aspect of the curriculum they seek to improve, namely core-curricular teaching, anatomy training, virtual reality, and electronic learning opportunities. We anticipate that the implementation of these suggestions will enhance medical school teaching.Keywords: surgical education, urology, medical school curriculum, modern educational technique
Ethnomedicine-based discovery and characterization of plant-derived GABAΑ receptor modulators with new scaffolds
No full textInhibitory neurotransmission in the central nervous system (CNS) largely relies on the actions of gamma aminobutyric acid (GABA) on GABAA receptors, heteropentameric ligand-gated chloride channels assembled from 19 possible subunits (α1-6, β1-3, γ1-3, δ, ε, θ, π, ρ1-3). GABA-induced chloride influx through GABAA receptors causes neuronal hyperpolarization and inhibition of further action potentials. Therefore, impaired GABAergic function results in CNS conditions such as epilepsy, insomnia, anxiety, and mood disorders. A number of clinically important drugs like benzodiazepines, barbiturates, neuroactive steroids, anesthetics, and certain other CNS depressants bind GABAA receptors. However, these drugs lack of subunit specificity and, therefore, induce serious side effects.
In the search for GABAA receptor modulators with new scaffolds, a plant extract library was screened at Prof. Hamburger’s group by means of an automated two-microelectrode voltage clamp functional assay in Xenopus laevis oocytes. Among others, the lipophilic extracts of Bupleurum chinense roots, Pholidota chinensis stems and roots, Adenocarpus cincinnatus roots and tubers, and Boswellia thurifera resin positively modulated GABAA receptors of the subtype α1β2γ2s, the most abundant one in the human brain.
In this work, GABAergic activity in the four extracts was tracked using of an HPLC-based activity profiling approach. In total, 22 natural products, eight of them new, were isolated by diverse chromatographic methods and characterized by HR-TOF-MS and microprobe NMR. Absolute configuration of chiral compounds was determined by CD-spectroscopy and polarimetry. Fourteen of the 22 isolates showed GABAA receptor modulatory activity in the oocyte functional assay. Dihydrostilbenes, cis-pterocarpans, and abietane diterpenes were identified as new scaffolds for GABAA receptor modulators with favorable physicochemical properties for blood-brain barrier permeation.
HPLC-based activity profiling of P. chinensis enabled the identification of the dihydrostilbene batatasin III as a very efficient, non-selective GABAA receptor modulator. Two structurally related non-flexible stilbenoids, coelonin and pholidotol D, were also isolated from the extract but showed no activity in the oocyte assay, suggesting conformational flexibility to be crucial for receptor modulation. This was confirmed by a preliminary structure-activity relationship study conducted with a series of commercially available stilbenes and their dihydro derivatives.
Fifteen flavonoid and isoflavonoid derivatives, including eight new natural products, were isolated from A. cincinnatus and tested in the oocyte assay. At a concentration of 100 μM, 12 of the 15 compounds significantly enhanced the GABA-induced chloride current through GABAA receptors. Two pterocarpans and one isoflavone showed remarkably higher potency than other natural products previously isolated in this working group (EC50 below 10 μM).
B. thurifera and B. chinense yielded two more GABAA receptor modulators, dehydroabietic acid and aristolactone, respectively. However, isolation of aristolactone from a commercial sample of the traditional Chinese herbal drug Chaihu (Bupleurum chinense roots) led to detection of adulteration of the sample with roots of the nephrotoxic species Aristolochia manshuriensis. This case raised concerns about adequate quality control of TCM drugs commercialized in Europe
Anàlisi genètica i funcional de la migranya hemiplègica i la migranya comuna
No full text[cat] Aquesta tesi es centra en la genètica de la migranya. La migranya comuna és un trastorn neurològic caracteritzat per episodis recurrents de mal de cap. Els criteris de la IHS (International Headache Society) subclasifiquen la malaltia en migranya amb aura (MA) i migranya sense aura (MO). L'aura són símptomes neurològics transitoris que poden acompanyar el mal de cap. Les aures més freqüents són les aures visuals, tot i que també existeixen les aures sensorials essent l'aura hemiplègica la seva forma severa. La nostra investigació es va dividir en dues areas d'acord amb la base genètica dels trastorns, d'una banda, s'ha estudiat la genètica complexa de la migranya comuna, d'altra banda s'ha estudiat una forma rara de la migranya que presenta una herència mendeliana anomenada migranya hemiplègica familiar (FHM).
Per entendre més la base genètica de la migranya comuna es va utilitzar un estudi d'associació tipus cas-control amb gens candidats. Amb aquesta finalitat es van seleccionar al voltant de 550 pacients amb migranya (MA i MO) i el seu corresponent grup de control. Per tal d'analitzar la seva implicació en la susceptibilitat genètica a la migranya, es van triar gens que codifiquen per als canals de la superfamília heterogeni de potencial receptor transitori (Transient Receptor Potential- TRP) que se sap que estan implicats en les vies nociceptives. Aquesta feina ha donat lloc a una publicació (Carreño et al. SNP variants within the vanilloid TRPV1 and TRPV3 receptor genes are associated with migraine in the Spanish population. Am J Med Genet B Neuropsychiatr Genet. 2012).
En el cas particular de les formes monogèniques de FHM es coneixen tres gens involucrats en la malatia (CACNA1A, ATP1A2 i SCN1A), les proteïnes codificades per aquests gens tenen un paper rellevant en la neurotransmissió del glutamat. L'anàlisi funcional de les mutacions que causen FHM han mostrat en última instància un augment de l'alliberament de la neurotransmissió. En el cas de mutacions al CACNA1A s'ha vist un efecte de guany de funció, a diferència de les mutacions al ATP1A2 que presenten un efecte de pèrdua de funció. En aquest treball s'ha fet un screening mutacional per identificar mutacions en pacients per seqüenciació directa. Quan les mutacions eren suficientment interessants s'han generat construccions en vectors d'expressió per subseqüents estudis funcionals en cèl·lules eucariotes. Aquesta feina ha donat lloc a tres publicacions. A la primera (Serra et al. A mutation in the first intracellular loop of CACNA1A prevents P/Q channel modulation by SNARE proteins and lowers exocytosis. Proc Natl Acad Sci. 2010) es va identificar un canvi que modula la funció del canal de CACNA1A. Aquest estudi ajuda a explicar la contribució genètica en la heterogeneïtat clínica d'una família i a entendre millor el mecanisme molecular dels canals de calci tipus P/Q. El segon (Carreño et al. Acute striatal necrosis in hemiplegic migraine with the novo CACNA1A mutation. Headache. 2011) és un informe d'un pacient que presenta una necrosi aguda stratial. Té una rellevància clínica a causa de l'aparició primerenca dels símptomes neurològics previs als atacs hemiplègics. El tercer i últim treball (Carreño et al. Screening of the ATP1A2 and CACNA1A genes in patients with hemiplegic migraine: clinical, genetic and functional studies. [work in progress]) recull l'screening mutacional al gens ATP1A2 i CACNA1A en 19 pacients amb FHM. Es van identificar 5 mutacions prèviament descrites i dues mutacions noves.[eng] This Thesis is focused in migraine genetics, migraine is a prevalent neurological disorder characterized by recurrent episodes of headache. This research was divided in two areas according to the genetic basis of the disorders; on the one hand we studied the common migraine with a complex genetics, on the other hand we studied the rare mendelian forms of familial hemiplegic migraine (FHM).
To understand more the genetic basis of the common migraine a case-control association study approach was used with candidate genes. For that purpose, around 550 patients with migraine and their corresponding control group were selected. In order to analyze their involvement in the genetic susceptibility to migraine, we chose genes encoding for channels of the heterogeneous superfamily of Transient Receptor Potential (TRP) which are known to be involved in the nociceptive pathway.
In the particular case of FHM, a monogenic form of the disorder, there are three genes known to be involved in the FHM (CACNA1A, ATP1A2 and SCN1A), whose encoded proteins are playing a relevant role in the neurotransmission of the glutamate. Functional analysis of the mutations causing FHM have shown ultimately an increased neurotransmission release. CACNA1A previous studies reveled a gain-of-function effect from FHM mutations, unlike mutations on ATP1A2 that present a loss-of-function effect. Our work consisted on identifying mutations in patients by direct sequencing. If the mutations were interesting enough vector constructions were generated for functional studies in eukaryotic cells. This work gave rise to three publications: First; the identification of a change that modulates the function of the CACNA1A channel. This study contributes to explain the genetic contribution in the clinical heterogeneity of one family and to know more about the molecular mechanism of the P/Q calcium channel. Second; a report of a patient that presents an acute stratial necrosis that had clinical relevance because of the early onset of the neurological symptoms previous to the hemiplegic attacks. Third; a mutational screening of ATP1A2 and CACNA1A genes in 19 patients with FHM. 5 previously described mutations and two new mutations were found. Functional studies were carried out for the newly mutations
The role of the lectin VIP36 in the early secretory pathway
No full textLectins are of emerging importance for quality control and intracellular transport of glycoproteins in mammalian cells. One of the most prominent lectins involved in intracellular transport is ERGIC-53, which belongs to the family of L-type lectins. ERGIC-53 mediates the ER export of several glycoproteins like cathepsin Z, α1-antitrypsin (α1-AT) or blood coagulation factors. VIP36 belongs to the same family as ERGIC-53, but its cellular function remains poorly understood. VIP36 is a type I membrane protein. It cycles within the early secretory pathway and binds high mannose glycans. In order to gain insight into the function of VIP36 we decided to search for a luminal interaction partner for VIP36.
We used a YFP-protein fragmentation complementation (YFP-PCA) based FACS screen of a human adult liver library to unravel an interaction partner for VIP36. Complementation of YFP is irreversible. Therefore, the YFP-PCA is well suited to detect weak interactions, like those between mammalian lectins and glycoproteins. YFP2-VIP36 was used as the bait in our screen. The human liver library was tagged with YFP1. Our screen identified α1-AT as an interaction partner for VIP36. VIP36 recognized high mannose containing α1-AT, which is consistent with the previously obtained results about the glycan affinity of VIP36. This interaction was increased upon inhibition of complex glycosylation by kifunensine. The complex formed by α1-AT and VIP36 was localized to the Golgi and the ER. α1-AT was previously identified as a cargo for ERGIC-53. Knockdown of ERGIC-53 slowed down α1-AT transport, consistent with a role for ERGIC-53 in ER export of α1-AT. In contrast, knockdown of VIP36 accelerated transport of endogenous α1-AT in HepG2 cells. This effect was specific for α1-AT, as the non-glycosylated protein albumin showed no acceleration in transport. In addition, VIP36 knockdown did not affect general protein secretion. This finding makes it unlikely that VIP36 acts as an anterograde cargo receptor for α1-AT. Further studies on the dynamics of the complex formed by VIP36 and α1-AT revealed that VIP36 recycles α1-AT back to the ER, which argues for a role of VIP36 in post-ER quality control. This notion is further supported by the finding that the chaperone BiP co-immunoprecipitated with the complex of VIP36 and α1-AT. This chaperone was previously described as an interaction partner for VIP36. This argues for a complex consisting of VIP36 and BiP acting together in post-ER quality control to detect misfolded α1-antitrypsin in the Golgi and retrieve it back to the ER.
Apart from searching for an interaction partner, I also determined the effect of depletion of VIP36 on the morphology of the secretory pathway. The rationale behind this is the observation that cargo receptors contribute to the structural integrity of organelles of the secretory pathway. Knockdown of VIP36 had no effect on ER exit sites or on the ERGIC. However, VIP36 knockdown resulted in fragmentation of the Golgi apparatus. The fragmented Golgi was not the consequence of disturbed bidirectional protein transport and not due to effects on microtubules. Knockdown of VIP36 reduced COPI staining on the Golgi. VIP36 is likely to provide COPI binding sites on the Golgi via its cytosolic tail and thereby contribute to Golgi structural integrity. Our results underscore the importance of cargo receptors, not only for intracellular transport within the secretory pathway, but also to maintain the integrity of the secretory pathway itself.
In conclusion, my thesis provides a deeper insight into the function of VIP36 in the early secretory pathway
Effects of fermentation products of silage on its intake by cattle
No full textThe end-products of silage fermentation have been implicated as factors limiting its intake by ruminant animals, although the contribution of individual chemical
components is not clearly understood. A series of experiments were conducted to investigate the effect of short-term intra-ruminal infusions of silage fermentation end products on roughage intake by cattle.
Infusions of lactic acid, the predominant organic acid found in well preserved silages were found to reduce the short-term intake of roughage by both steers and dairy
cows. The short-term intake of hay- and silage- fed steers was reduced by infusions of 32 g lactic acid/kgDMI. The reduction in intake was greater when the acid was infused
over two hours as opposed to one hour. The same amount of lactic acid (32 g/kgDMI) reduced the intake of silage fed dairy cows. These results were substantiated by a further
experiment in which intra-ruminal infusions of 16, 32 or 48 g lactic acid/kgDMI over a two hour period reduced the short-term intake of silage-fed steers in a dose related
manner.
The mechanism by which lactic acid reduces intake was not clear from these trials. Infusions of acetic and propionic acids in the molar proportions to which lactic acid is metabolised in the rumen depressed silage intake by dairy cows, but this was attributed to a fall in rumen pH.
Urea, used to mimic silage ammonia had no effect on voluntary intake of hayand silage- fed cattle. This supports the theory that rather than ammonia per se limiting
intake it is other fermentation end-products, such as silage amines, produced in similar conditions to ammonia that are responsible for poor intakes.
Amines were detected in noticeable amounts in silages made at Hurley. The predominant one being gamma amino-n-butyric acid (Gaba). Infusion of Gaba intraruminally, reduced the intake of silage-fed steers by up to 22%. Given in combination with putrescine the depressing effect of intake depression was doubled (44%), although these results were not significant. Physical gut fill was found to have
little effect in the limitation of short-term silage intake. Rumen emptying studies showed that the maximum amount of digesta present within the rumen, in terms of DM, OM and NDF occurred after the cessation of the first meal
Efeitos comportamentais da microinjeção de mCPP na concha do núcleo accumbens de ratos sob restrição alimentar
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-graduação em Neurociências, Florianópolis, 2010Efeito do sistema serotonérgico sobre a ingestão de alimentos e o consumo de água, bem como nos níveis de comportamentos relacionados à ansiedade/medo em ratos submetidos à restrição parcial de alimentos. Investigação do envolvimento dos receptores serotonérgicos 5-HT1B e 5-HT2C através da administração local bilateral de mCPP na região concha do núcleo accumbens, a fim de estabelecer uma possível relação entre o comportamento de ingestão de alimentos e o comportamento de ansiedade
Changes in Muscle Strength in U19 Soccer Players During an Annual Training Cycle
No full textThe aim of the study was to investigate the seasonal variation in isokinetic strength of the knee flexors and extensors, and conventional (H/QCONV) and functional (H/QFUNC) hamstring to quadriceps strength ratios in highly trained adolescent soccer players. The players (n=11; age 17.8±0.3) were measured at the end of the competitive season (autumn), at the beginning and the end of pre-season (winter) and during the sixth week of a new competitive season. Isokinetic peak torque (concentric and eccentric) was measured at 60°·s-1 in a sitting position with the hip flexed at 100°. The testing range of motion was set from 10 – 90° of knee flexion. The players performed a set of five maximum repetitions for both the dominant and non-dominant leg. Statistically significant differences (p<0.001) between the four seasonal measurements were noted for peak torque of the dominant leg knee flexors in concentric muscle action only. A post hoc analysis revealed a statistically significant increase in peak torque from the 1st to the 4th measurement (p<0.001; d=0.692) and from the 2nd to the 4th (p<0.01; d=0.564). The differences in the changes of peak torque of the knee flexors and extensors depending on type of muscle action and tendencies found in the H/Q ratios throughout the annual training cycle indicate that strength assessment of the knee flexors and extensors and their balance throughout the annual training cycle could be beneficial for elite male adolescent soccer players both in terms of performance and risk of injury
Parent-of-origin-specific allelic associations among 106 genomic loci for age at menarche.
No full textAge at menarche is a marker of timing of puberty in females. It varies widely between individuals, is a heritable trait and is associated with risks for obesity, type 2 diabetes, cardiovascular disease, breast cancer and all-cause mortality. Studies of rare human disorders of puberty and animal models point to a complex hypothalamic-pituitary-hormonal regulation, but the mechanisms that determine pubertal timing and underlie its links to disease risk remain unclear. Here, using genome-wide and custom-genotyping arrays in up to 182,416 women of European descent from 57 studies, we found robust evidence (P < 5 × 10(-8)) for 123 signals at 106 genomic loci associated with age at menarche. Many loci were associated with other pubertal traits in both sexes, and there was substantial overlap with genes implicated in body mass index and various diseases, including rare disorders of puberty. Menarche signals were enriched in imprinted regions, with three loci (DLK1-WDR25, MKRN3-MAGEL2 and KCNK9) demonstrating parent-of-origin-specific associations concordant with known parental expression patterns. Pathway analyses implicated nuclear hormone receptors, particularly retinoic acid and γ-aminobutyric acid-B2 receptor signalling, among novel mechanisms that regulate pubertal timing in humans. Our findings suggest a genetic architecture involving at least hundreds of common variants in the coordinated timing of the pubertal transition
A possible role of the locus coeruleus in complex regional pain syndrome
No full textHeightened sensitivity to painful stimulation commonly spreads from the affected limb to the ipsilateral forehead in patients with complex regional pain syndrome (CRPS). In addition, acoustic startle evokes greater auditory discomfort and increases in limb pain when presented on the affected than unaffected side. In contrast, limb pain ordinarily evokes analgesia in the ipsilateral forehead of healthy participants, and acoustic startle suppresses limb pain. Together, these findings suggest that hemilateral and generalized pain control mechanisms are disrupted in CRPS, and that multisensory integrative processes are compromised. Failure to inhibit nociceptive input from the CRPS-affected limb could sensitize spinal and supraspinal neurons that receive convergent nociceptive and auditory information from hemilateral body sites. Somatosensory, auditory and emotional inputs may then aggravate pain by feeding into this sensitized nociceptive network. In particular, a disturbance in hemilateral pain processing that involves the locus coeruleus could exacerbate the symptoms of CRPS in some patients
