HUBUNGAN EKSPRESI BRAFV600E DENGAN VARIAN HISTOPATOLOGI DAN INFILTRASI LIMFOSIT PADA PAPILLARY THYROID CARCINOMA (PTC)

Karsinoma tiroid merupakan keganasan kelenjar endokrin yang paling sering ditemukan yaitu sekitar 95 % dari seluruh keganasan endokrin. Papillary thyroid carcinoma (PTC) memiliki angka kejadian paling tinggi dari karsinoma tiroid yaitu sekitar 60-80%. Papillary thyroid carcinoma secara umum mempunyai pertumbuhan lambat dan memiliki prognosis yang sangat baik. Mutasi BRAFV600E berperan penting pada karsinogenesis beberapa karsinoma termasuk PTC. BRAFV600E adalah suatu RAS-regulated serin-threonine kinase dan aktivator kaskade jalur MAPK, yang berfungsi mengatur proliferasi, differensiasi dan survival sel. Mutasi BRAFV600E pada PTC dikaitkan dengan tingginya kejadian rekurensi, invasi ekstratiroid, metastasis kelenjar getah bening dan metastasis jauh, stadium lanjut dan mengurangi kelangsungan hidup. Studi sebelumnya menunjukkan terdapat hubungan ekspresi BRAFV600E dengan faktor prognostik yang buruk pada PTC diantaranya varian histopatolgik dan infiltrasi limfosit. Namun hal lain masih menjadi kontroversi. Tujuan penelitian ini untuk melihat hubungan ekspresi BRAFV600E dengan varian histopatologik dan infiltrasi limfosit pada papillary thyroid carcinoma. Penelitian ini merupakan penelitian observasional dengan desain cross sectional dengan sampel penelitian sebanyak 40 kasus PTC yang telah didiagnosis di 4 Laboratorium Patologi Anatomik di Sumatera Barat. Sampel diperoleh dari blok paraffin yang berasal dari jaringan hasil operasi dan dilakukan reevaluasi terhadap varian histopatologik dan infiltrasi limfosit. Ekspresi BRAFV600E pada sel tumor dilihat dengan pewarnaan imunohistokimia. Analisis statistik bivariat menggunakan uji chi square dengan p<0,05 dianggap bermakna. Ekspresi BRAFV600E positif ditemukan pada 24 kasus (60%). Ekspresi BRAFV600E positif paling banyak ditemukan pada kasus classic PTC (50%). Kasus PTC dengan infiltrasi limfosit paling banyak ditemukan dengan ekspresi BRAFV600E negatif (79,2 %). Analisis statistik menunjukkan tidak terdapat hubungan bermakna antara ekspresi BRAFV600E dengan varian histopatologik dengan (p=0,74) dan tidak terdapat hubungan bermakna antara ekspresi BRAFV600E dengan infiltrasi limfosit (p=0,12). Kesimpulan penelitian ini tidak terdapat hubungan bermakna antara ekspresi BRAFV600E dengan varian histopatologi dan tidak terdapat hubungan yang bermakna antara ekspresi BRAFV600E dengan infiltrasi limfosit. Kata kunci : papillary thyroid carcinoma, ekspresi BRAFV600E, varian histopatologik, infiltrasi limfosit

Synaptic plasticity in medial vestibular nucleus neurons: comparison with computational requirements of VOR adaptation

Background: Vestibulo-ocular reflex (VOR) gain adaptation, a longstanding experimental model of cerebellar learning, utilizes sites of plasticity in both cerebellar cortex and brainstem. However, the mechanisms by which the activity of cortical Purkinje cells may guide synaptic plasticity in brainstem vestibular neurons are unclear. Theoretical analyses indicate that vestibular plasticity should depend upon the correlation between Purkinje cell and vestibular afferent inputs, so that, in gain-down learning for example, increased cortical activity should induce long-term depression (LTD) at vestibular synapses. Methodology/Principal Findings: Here we expressed this correlational learning rule in its simplest form, as an anti-Hebbian, heterosynaptic spike-timing dependent plasticity interaction between excitatory (vestibular) and inhibitory (floccular) inputs converging on medial vestibular nucleus (MVN) neurons (input-spike-timing dependent plasticity, iSTDP). To test this rule, we stimulated vestibular afferents to evoke EPSCs in rat MVN neurons in vitro. Control EPSC recordings were followed by an induction protocol where membrane hyperpolarizing pulses, mimicking IPSPs evoked by flocculus inputs, were paired with single vestibular nerve stimuli. A robust LTD developed at vestibular synapses when the afferent EPSPs coincided with membrane hyperpolarisation, while EPSPs occurring before or after the simulated IPSPs induced no lasting change. Furthermore, the iSTDP rule also successfully predicted the effects of a complex protocol using EPSP trains designed to mimic classical conditioning. Conclusions: These results, in strong support of theoretical predictions, suggest that the cerebellum alters the strength of vestibular synapses on MVN neurons through hetero-synaptic, anti-Hebbian iSTDP. Since the iSTDP rule does not depend on post-synaptic firing, it suggests a possible mechanism for VOR adaptation without compromising gaze-holding and VOR performance in vivo

Hypothalamic Melanocortin Regulation of Energy Balance and Metabolism

Genetic and environmental factors both contribute to obesity, however studies in twins and adoptees demonstrate that genetic predisposition and susceptibility are driving factors in the development of this disease. Although numerous human mutations are associated with an increase in obesity prevalence, melanocortin-4 receptor (MC4-R) mutations are the most common monogenic form of severe obesity and genetic deletion of this receptor in rodents also leads to an obese phenotype. The G-protein coupled MC4-R is a target for the peptide products of Proopiomelanocortin (POMC) and Agouti-related peptide (AgRP) neurons residing in the arcuate nucleus of the hypothalamus. POMC-derived alpha-melanocyte-stimulating hormone (MSH) is an agonist for the MC4-R and promotes negative energy balance, while the melanocortin-receptor antagonist AgRP promotes positive energy balance. Given the strong influence of the hypothalamic melanocortin system on energy balance, this thesis sought to investigate unexplored aspects of this system in relation to obesity. POMC is post-translationally processed to biologically active peptides with opposing actions. Alpha-MSH is well established to decrease food intake and increase energy expenditure, however POMC-derived beta-endorphin (beta-EP) has been shown in limited studies to increase food intake. Our experiments in intracerebroventricular (icv) cannulated rats demonstrate that the effects of beta-EP alone on feeding are complex. Beta-EP acutely stimulated food intake during both the light and dark cycle, however orexigenic effects were not sustained in a chronic model; in fact, higher doses of chronic beta-EP decreased food intake. Subthreshold doses of beta-EP also reversed alpha-MSH-induced suppression in feeding and weight gain in an acute fasting and refeeding model as well as a chronic infusion model. Beta-EP 1-27, a product of C-terminal beta-EP cleavage reported to have reduced opioid activity, did not stimulate food intake alone, nor could it reverse alpha-MSH-induced suppression in feeding. These studies show that POMC-derived peptides alpha-MSH and beta-EP can interact to regulate food intake and body weight and highlight the importance of understanding how the balance between these peptides is maintained, as well as the potential role of differential POMC processing in regulating energy balance. AgRP is also a critical component of the melanocortin system; however, studies in which the AgRP peptide was deleted show only a mild phenotype suggesting that developmental compensation exists in this model. Consequently the role of the AgRP peptide was investigated using a novel AgRP inhibitor developed by TransTech Pharma, Inc. Results show that this inhibitor was extremely effective in reversing exogenous icv AgRP-induced metabolic and neuroendocrine parameters in rats, and these parameters were unaffected in saline infused rats receiving this drug. This AgRP inhibitor also reduced food intake, weight gain and adiposity in diet-induced obese (DIO) and ob/ob mice and increased thyroxine (T4) levels in DIO mice, consistent with AgRP's reported effects; however this drug did not affect food intake or weight gain in lean chow fed mice. The AgRP inhibitor also suppressed rebound feeding and potently reduced food intake in mice immediately upon initiation of a high fat diet (HFD). As some of these effects were also observed in AgRP knockout (KO) mice, this indicates that there are clear off-target effects that are not due to AgRP antagonism. Although there are many potential reasons why a drug may yield anorexia and weight loss, the fact that these effects were only observed in obese models or in the presence of increased dietary fat, suggests the possibility that another molecule that promotes positive energy balance and fat intake is also being targeted. As the melanocortin system can also regulate pituitary function, this thesis investigated circulating and pituitary prolactin levels in models with genetic manipulation of this system. Previous studies have shown that acute stimulation of the melanocortin system by alpha-MSH or antagonism by AgRP decreases and increases prolactin levels, respectively. However, the effects of chronic melanocortin manipulation were unknown. Male mice with selective MSH overexpression and AgRP deletion were found to have decreased blood prolactin levels under both stressed and unstressed conditions, and mice with AgRP deletion also had lower prolactin content in the pituitary. As prolactin is tonically inhibited by dopamine and acute melanocortin regulation of prolactin release has been shown to be dopamine-mediated, we sought to show this mechanism in these genetic models. Measurements of mediobasal hypothalamic (MBH) tyrosine hydroxylase mRNA levels as well as dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content did not differ between groups, nor did prolactin measurements after functional dopamine receptor antagonism. However, these results do not preclude changes in dopamine activity as dopamine turnover was not directly investigated. This is the first report of reduced baseline and stress-induced prolactin release and pituitary prolactin content in mice with genetic alterations of the melanocortin system and suggests that changes in hypothalamic melanocortin activity may be reflected in measurements of serum prolactin levels. The melanocortin system has been shown to mediate some of the adaptive responses after introduction to the HFD including attenuation of hyperphagia and weight gain; thus, preliminary studies sought to investigate the effects of the HFD on hypothalamic melanocortin gene and peptide expression, as well as expression of enzymes responsible for POMC post-translational processing. Mice administered a 60% HFD were found to have increased levels of POMC precursor peptide after both acute (3 and 7 days) and chronic (8 week) HFD administration. After 3 days of HFD feeding, increased POMC peptide levels were accompanied by increased Pomc mRNA and alpha-MSH and beta-EP, however after chronic HFD feeding POMC peptide levels were elevated without an increase in these parameters. Additionally, chronic HFD feeding suppressed AgRP mRNA and peptide levels and tended to increase the alpha-MSH/beta-EP ratio and suppress mRNA levels of prolylcarboxypeptidase (Prcp), an enzyme responsible for inactivating alpha-MSH. These data suggest that the HFD can modulate melanocortin gene and peptide expression with distinct time-related changes and are consistent with the hypothesis that POMC-derived peptides act in concert to regulate energy balance and metabolism. However, these results are preliminary and further investigation of the effects of HFD feeding on peptide and processing enzyme expression in more anatomically discrete hypothalamic nuclei as well as dynamic studies of peptide release are required. These data provide a contribution to the field of melanocortin regulation of energy balance by further elucidating the effects of POMC processed peptides both alone and in interaction, by providing insight into the effects of a novel AgRP inhibitor on energy balance and metabolism, by investigating the effects of genetic models of chronic melanocortin manipulation on the pituitary hormone prolactin, as well as by examining the effects of HFD feeding on melanocortin gene and peptide expression

Community-based physical activity interventions for adolescents and adults with complex cerebral palsy : A scoping review

Aim To identify implementation strategies and safety outcomes (adverse events) of community-based physical activity interventions for adolescents and adults with complex cerebral palsy (CP). Method Five electronic databases were systematically searched to April 2022. Data were extracted on the implementation and safety of physical activity interventions for adolescents and adults with CP, classified in Gross Motor Function Classification System (GMFCS) levels IV and V, delivered in a community setting. Results Seventeen studies with 262 participants (160 participants classified in GMFCS levels IV or V) were included. Community settings included schools (n = 4), participants' homes (n = 3), gymnasia (n = 2), swimming pools (n = 2), and other settings (n = 4). Most studies specified medical or safety exclusion criteria. Implementation strategies included pre-exercise screening, use of adapted equipment, familiarization sessions, supervision, physical assistance, and physiological monitoring. Attendance was high and attrition low. Nine studies reported non-serious, expected, and related events. Four studies reported minor soreness and four studies reported minor fatigue post-exercise. Serious adverse events related to exercise were infrequent (reported for 4 of 160 participants [<2%]: three participants withdrew from an exercise programme and one participant ceased exercise for a short period). Most frequently reported was pain, requiring temporary exercise cessation or programme change, or study withdrawal (three participants). Interpretation For most adolescents and adults with CP classified in GMFCS levels IV and V, physical activity interventions can be safely performed in a community setting, without post-exercise pain or fatigue, or serious adverse events

The excitation of muscle stretch receptors by suxamethonium

1. Changes in the response of cat soleus muscle spindle primary, secondary and "intermediate" sensory endings to ramp stretchin during intravenous and intra-arterial infusions of suxamethonium (SCh) in the intact anaesthetised animal have been studied. The effects of SCh on the spindle sensory endings have been related to the known action of SCh and ACh on the two nuclear bag intrafusal muscle fibres of isolated cat muscle spindles in vitio (Gladden 1976) 2. The application of repetitive short-duration ramp-and-hold test stretches to the soleus muscle during continuous slow infusion of SCh enabled the gradual activation of the spindle sensory endings to be studied in detail. Typical muscle spindle primary sensory endings were activated in three consecutive stages during infusion of SCh, which will be termed Phases I, II and III of excitation. In Phase I of excitation, a gradual facilitatory effect of SCh on tha discharge of the Ia sensory endings accompanied by a progressive reduction in the sensitivity of the endings to liuscle shortening was observed. This occurred without a potentiation of, and usually a decrease in, the dynamic and position sensitivities of the Ia endings to muscle stretch. The Phase I facilitatory effects of SCh on la endings appear not to be caused by the contraction of intrafusal muscle fibres, and are probably the result of a direct or indirect depolarising action of SCh on the sensory nerve terminals of the la afferent axon. In Phase II of excitation, the sensitivity of the Ia endings to the dynamic phase of the ramp stretch increased dramatically, and the response of the endings to stretch was very similar to that of la endings during strong dynamic fusimotor activation. This increase in the dynamic sensitivity is very likely the result of the recruitment of the dynamic nuclear bag (DNB) fibre, which has the lower threshold of SCh of the two nuclear bag fibres (Gladden 1976), and which is made to contract by dynamic fusi- motor axons (Boyd, Gladden, McWilliam&Ward 1977), In Phase III of excitation, a marked increase in the position sensitivity of the Ia endings was superimposed on the already enhanced dynamic sensitivity, and the response of the la endings to stretch became very similar to that during combined stimulation of powerful dynamic and static fusi-motor axons. The increase in the position sensitivity of the Ia endings in Phase III of activation no doubt reflects the contraction of the static nuclear bag (SNB) fibre, which has the higher threshold to SCh of the two nuclear bag fibres (Gladden 1976). The characteristic response to stretch of la endings in Phase III of excitation is thus the result of the combined activation of the dynamic and static nuclear bag fibres by SCh. 3. Unlike soleus muscle spindle primary sensory endings, secondary endings showed only a gradual facilitation of their discharge during infusion of SCh, and behaved in a similar way to Ia endings in Phase I of excitation. while Ia endings subsequently experienced large increases in their dynamic and position sensitivities following the recruitment of the two nuclear bag fibres, secondary sensory endings did not show similar effects. The activation of typical secondary sensory endings by SCh therefore appears to be entirely the result of a direct or indirect depolarising action of SCh on the afferent nerve terminals, without any apparent contribution from the contraction of the two nuclear bag fibres

Pathological changes in the spleens of gamma interferon receptor-deficient mice infected with murine gammaherpesvirus:a role for CD8 T cells

Murine gammaherpesvirus is a natural rodent pathogen which causes a primary infection in the lungs and establishes a persistent infection in B lymphocytes. During the primary infection, large amounts of gamma interferon (IFN-gamma) are produced by spleen, mediastinal, and cervical lymph node cells. To investigate the role of IFN-gamma in control of the virus infection, mice lacking the cellular receptor for IFN-gamma (IFN-gamma R-/- mice) were infected with murine gammaherpesvirus 68 (MHV68). IFN-gamma R-/- mice showed no difference from wild-type mice in the titers of infectious virus in the lungs or in the rate of clearance of the lung infection. In the spleen, however, clear differences were observed. By 14 days postinfection, spleens from IFN-gamma R-/- mice were pale, shrunken, and fibrous. Histological examination showed that there was an early (day 10) infiltration of granulocytes followed by widespread destruction of splenic architecture (days 14 to 17). A marked decrease in the number of splenic B cells and CD4+ and CD8+ T cells occurred. These changes were accompanied by a 10- to 100-fold greater load of latently infected cells in IFN-gamma R-/- mice than in wild-type mice at 14 to 17 days postinfection, but this was reduced to the levels found in wild-type mice by 21 days postinfection. Treatment of the mice with the antiviral drug 2'-deoxyl-5-ethyl-beta-4'-thiouridine from 6 days postinfection did not prevent the occurrence of these changes. The changes were, however, completely reversed by depletion of CD8+ T cells prior to and during the primary infection. Depletion of CD4+ T cells also reversed the major pathological and virological changes, although in this case there was evidence of some histological changes. Thus, the lack of IFN-gamma receptor had profound consequences in spleens of MHV68-infected mice. The possible mechanisms involved in these changes are discussed

Time cost associated with sports participation for athletes with high support needs : A time-motion analysis of tasks required for para swimming

Objectives People with cerebral palsy and high support needs (CP&HSN) are profoundly inactive but also under-represented in studies evaluating physical activity interventions. Reasons for their exclusion have not been evaluated. We hypothesised that CP&HSN would be associated with high time costs of preparatory activities (eg, getting dressed/undressed), possibly contributing to low participation and under-representation. Accordingly, this pilot study aimed to: (1) evaluate whether the time required for preparatory activities was extremely different (≥3 SD) between swimmers with and without CP&HSN; and (2) provide a qualitative indication of the preparatory tasks undertaken by swimmers with CP&HSN. Methods Each of three experienced (5 years) para swimmers with CP&HSN and 20 non-disabled swimmers were timed entering and then exiting the pool on three occasions. Mean entry and exit time for each para swimmer was compared with the group mean for non-disabled swimmers, and differences of greater than 3.0 SD were considered extreme. A qualitative description of the tasks completed by the para swimmers was recorded. Results The differences in time costs between para and non-disabled swimmers met the criterion of extreme. Pool entry times for para swimmers were 8–13 times greater (Effect size = 4.1–8.7). Pool exit times were 6–10 times greater (ES=7.0–9.5). 90% of tasks completed by para swimmers required personal assistance or wheeled mobility. Conclusions This pilot study suggests that, compared with non-disabled swimmers, time costs for preparation to commence or depart training are extremely high for swimmers with CP&HSN. Further research is required to evaluate the veracity of these findings

Concurrent infection with the filarial helminth Litomosoides sigmodontis attenuates or worsens Influenza A virus pathogenesis in a stage-dependent manner

Filarial helminths infect approximately 120 million people worldwide initiating a type 2 immune response in the host. Influenza A viruses stimulate a virulent type 1 pro-inflammatory immune response that in some individuals can cause uncontrolled immunopathology and fatality. Although coinfection with filariasis and influenza is a common occurrence, the impact of filarial infection on respiratory viral infection is unknown. The aim of this study was to determine the impact of pre-existing filarial infection on concurrent infection with influenza A virus. A murine model of co-infection was established using the filarial helminth Litomosoides sigmodontis and the H1N1 (A/WSN/33) influenza A virus (IAV). Co-infection was performed at 3 different stages of L. sigmodontis infection (larval, juvenile adult, and patency), and the impact of co-infection was determined by IAV induced weight loss and clinical signs, quantification of viral titres, and helminth counts. Significant alterations of IAV pathogenesis, dependent upon stage of infection, was observed on co-infection with L. sigmodontis. Larval stage L. sigmodontis infection alleviated clinical signs of IAV co-infection, whilst more established juvenile adult infection also significantly delayed weight loss. Viral titres remained unaltered at either infection stage. In contrast, patent L. sigmdodontis infection led to a reversal of age-related resistance to IAV infection, significantly increasing weight loss and clinical signs of infection as well as increasing IAV titre. These data demonstrate that the progression of influenza infection can be ameliorated or worsened by pre-existing filarial infection, with the outcome dependent upon the stage of filarial infection