Exercise protects synaptic density in a rat model of Parkinson's disease.

BACKGROUND: Parkinson's disease (PD) is characterized by Lewy body and neurite pathology associated with dopamine terminal dysfunction. Clinically, it is associated with motor slowing, rigidity, and tremor. Postural instability and pain are also features. Physical exercise benefits PD patients - possibly by promoting neuroplasticity including synaptic regeneration. OBJECTIVES: In a parkinsonian rat model, we test the hypotheses that exercise: (a) increases synaptic density and reduces neuroinflammation and (b) lowers the nociceptive threshold by increasing µ-opioid receptor expression. METHODS: Brain autoradiography was performed on rats unilaterally injected with either 6-hydroxydopamine (6-OHDA) or saline and subjected to treadmill exercise over 5 weeks. [3H]UCB-J was used to measure synaptic vesicle glycoprotein 2A (SV2A) density. Dopamine D2/3 receptor and µ-opioid receptor availability were assessed with [3H]Raclopride and [3H]DAMGO, respectively, while neuroinflammation was detected with the 18kDA translocator protein (TSPO) marker [3H]PK11195. The nociceptive threshold was determined prior to and throughout the exercise protocol. RESULTS: We confirmed a dopaminegic deficit with increased striatal [3H]Raclopride D2/3 receptor availability and reduced nigral tyrosine hydroxylase immunoreactivity in the ipsilateral hemisphere of all 6-OHDA-injected rats. Sedentary rats lesioned with 6-OHDA showed significant reduction of ipsilateral striatal and substantia nigra [3H]UCB-J binding while [3H]PK11195 showed increased ipsilateral striatal neuroinflammation. Lesioned rats who exercised had higher levels of ipsilateral striatal [3H]UCB-J binding and lower levels of neuroinflammation compared to sedentary lesioned rats. Striatal 6-OHDA injections reduced thalamic µ-opioid receptor availability but subsequent exercise restored binding. Exercise also raised thalamic and hippocampal SV2A synaptic density in 6-OHDA lesioned rats, accompanied by a rise in nociceptive threshold. CONCLUSION: These data suggest that treadmill exercise protects nigral and striatal synaptic integrity in a rat lesion model of PD - possibly by promoting compensatory mechanisms. Exercise was also associated with reduced neuroinflammation post lesioning and altered opioid transmission resulting in an increased nociceptive threshold.

The rpl23 gene and pseudogene are hotspots of illegitimate recombination in barley chloroplast mutator seedlings.

Previously, through a TILLING (Targeting Induced Local Lesions in Genomes) approach applied on barley chloroplast mutator (cpm) seedlings a high frequency of polymorphisms in the rpl23 gene was detected. All the polymorphisms corresponded to five differences already known to exist in nature between the rpl23 gene located in the inverted repeats (IRs) and the rpl23 pseudogene located in the large single copy region (LSC). In this investigation, polymorphisms in the rpl23 gene were verified and besides, a similar situation was found for the pseudogene in cpm seedlings. On the other hand, no polymorphisms were found in any of those loci in 40 wild type barley seedlings. Those facts and the independent occurrence of polymorphisms in the gene and pseudogene in individual seedlings suggest that the detected polymorphisms initially arose from gene conversion between gene and pseudogene. Moreover, an additional recombination process involving small recombinant segments seems to occur between the two gene copies as a consequence of their location in the IRs. These and previous results support the hypothesis that the CPM protein is a component of the plastome mismatch repair (MMR) system, whose failure of the anti-recombination activity results in increased illegitimate recombination between the rpl23 gene and pseudogene.

Tin-carbon clusters and the onset of microscopic level immiscibility: Experimental and computational study.

We report the experimental observation and computational analysis of the binary tin-carbon gas phase species. These novel ionic compounds are generated by impact of C60(-) anions on a clean tin target at some kiloelectronvolts kinetic energies. Positive Sn(m)C(n)(+) (m = 1-12, 1 ≤ n ≤ 8) ions were detected mass spectrometrically following ejection from the surface. Impact induced shattering of the C60(-) ion followed by sub-surface penetration of the resulting atomic carbon flux forces efficient mixing between target and projectile atoms even though the two elements (Sn/C) are completely immiscible in the bulk. This approach of C60(-) ion beam induced synthesis can be considered as an effective way for producing novel metal-carbon species of the so-called non-carbide forming elements, thus exploring the possible onset of molecular level miscibility in these systems. Sn2C2(+) was found to be the most abundant carbide cluster ion. Its instantaneous formation kinetics and its measured kinetic energy distribution while exiting the surface demonstrate a single impact formation/emission event (on the sub-ps time scale). Optimal geometries were calculated for both neutral and positively charged species using Born-Oppenheimer molecular dynamics for identifying global minima, followed by density functional theory (DFT) structure optimization and energy calculations at the coupled cluster singles, doubles and perturbative triples [CCSD(T)] level. The calculated structures reflect two distinct binding tendencies. The carbon rich species exhibit polyynic/cummulenic nature (tin end capped carbon chains) while the more stoichiometrically balanced species have larger contributions of metal-metal bonding, sometimes resulting in distinct tin and carbon moieties attached to each other (segregated structures). The Sn2C(n) (n = 3-8) and Sn2C(n)(+) (n = 2-8) are polyynic/cummulenic while all neutral Sn(m)C(n) structures (m = 3-4) could be described as small tin clusters (dimer, trimer, and tetramer, correspondingly) attached to a nearly linear carbon chain. For example, the 1:1 (Sn:C) Sn3C3 and Sn4C4 clusters are composed of all-tin triangle and rhombus, correspondingly, with a short carbon chain (C3, C4) attached on top. The cationic Sn3C(n)(+) (n = 1-5) and Sn4C(n)(+) (n = 1-4) species exhibit various intermediate geometries. Structure calculations at the CCSD(T) level are essential since the segregation effect is not as easily evident based on the most stable structures calculated by DFT alone. Dependences of bond energies (per atom) reflect the evolution of the segregation effect. The mass spectral abundances could be reasonably rationalized in terms of calculated stabilities of the cluster ions with respect to various dissociation channels.

An evaluation of the first time performance of international medical graduates in the MRCOG Part 1 and Part 2 written examinations.

OBJECTIVES: To evaluate the performance of international medical graduates in the MRCOG Part 1 and Part 2 written examinations. STUDY DESIGN: Using the database of the Royal College of Obstetricians and Gynaecologists, a retrospective analysis was performed of the performance of overseas candidates who appeared for the first time in the Part 1 (n=11,863) and Part 2 written (n=5336) MRCOG examinations between 2000 and 2010. Candidates were grouped according to the RCOG geographical bands. RESULTS: In the Part 1 MRCOG examination the graduates of band E (India and Pakistan) and band B (Australia, New Zealand and Canada) performed well (pass rate 41.2% and 39.3% respectively) but the candidates of band C (East Africa 27.1%) and bands J and A (Europe 29.9%, Ireland 17.9%) underperformed. In the MRCOG Part 2 written examination the medical graduates of band D (Singapore and Hong Kong) and band B (Australia, New Zealand and Canada) performed well (pass rates 65.9% and 54.8%), but the candidates of band H (Middle East, pass rate 8.5%) and band C (Africa West, pass rate 12.7%) performed worse than the remaining cohort. The greatest number of candidates in the Part 2 written examinations appeared from India and Pakistan (n=2999, pass rate 22.2%). CONCLUSION: Our results have shown that there is variation in performance among the IMG from different geographical regions in the Part 1 and Part 2 written MRCOG examinations.

An analysis of the performance of UK medical graduates in the MRCOG Part 1 and Part 2 written examinations.

BACKGROUND: There is a lack of evidence on whether graduates from different medical schools perform differently in postgraduate examinations. OBJECTIVE: To evaluate the variations in performance of UK medical graduates in Member of the Royal College of Obstetricians and Gynaecologists (MRCOG) examination. METHODS: A retrospective analysis of performance of 1335 doctors graduating in UK medical schools who entered the Part 1 MRCOG and 822 doctors taking the Part 2 MRCOG written examination for the first time between 1998 and 2008. The main outcome measures were to evaluate medical school effects, gender effects and academic performance effect. RESULTS: Graduates of UK medical schools performed differently in the Part 1 and Part 2 written MRCOG examination. The graduates of Oxford (pass rate 82.6%), Cambridge (75%), Bristol (59.3%) and Edinburgh (57.5%) performed significantly better and the graduates of Liverpool (26.8%), Southampton (21.8%) and Wales (18.2%) performed significantly worse than the remaining cohort in the Part 1 examination. The candidates of Newcastle (88.9%), Oxford (82.4%), Cambridge (81%) and Edinburgh (78.2%) performed significantly better and the graduates of Glasgow (49.2%) and Leicester (36.2%) have significantly underperformed compared with the remaining cohort in Part 2 written examination. There was no difference in the success rates of male (47.5%) and female (42.0%) candidates in the Part 1; however, female candidates had a significantly better success rate in the Part 2 written examination than male candidates (65.6% vs 52.9%). CONCLUSION: These results show that there is variation in performance among the graduates from different medical schools in the Part 1 and Part 2 MRCOG written examination.

Sensory neuron and substance P involvement in symptoms of a zymosan-induced rat model of acute bowel inflammation.

Intestinal inflammation is a painful syndrome with multiple symptoms, including chronic pain. This study examined the possible role of sensory neurons and substance P in symptoms of an animal model of acute intestinal inflammation. The model was induced by injecting ethanol and zymosan into the colon of anesthetized male rats. Three hours later, sections of the colon were stained with hematoxylin and eosin. To determine the role of substance P, 5 mg/kg of the neurokinin-1 receptor (NK-1r) antagonist, CP-96,345, or 300 microg/kg of an antisense oligonucleotide targeted at NK-1r mRNA was administered. Spinal cord sections were examined for internalization of NK-1r, as an indicator of substance P release. Sections of colon revealed infiltration of inflammatory cells following ethanol and zymosan treatment. Plasma extravasation in rats given ethanol and zymosan was significantly greater than in controls given saline only (P<0.0001) or saline and ethanol (P<0.001). In ethanol- and zymosan-treated rats given CP-96,345, plasma extravasation was significantly less than in rats given ethanol and zymosan without the antagonist (P<0.0001). Administration of the antisense oligonucleotide also resulted in lower levels of plasma extravasation compared with controls (P<0.01). Internalization of the NK-1r was observed in neurons of lamina I in the T13-L2 and L6-S2 regions of the spinal cord, as well as in sympathetic preganglionic neurons at the L1 level. This internalization was observed in the absence of any other stimulus besides the inflammation itself. This study implicates substance P and its receptor, the NK-1r, in acute inflammation of the colon.

Liver injuries in children: the role of selective non-operative management.

INTRODUCTION: This review article on the management of blunt liver injury in children is based on the authors' experience of 311 patients over a 22-year period. MATERIAL AND METHODS: All children presenting to our institution with confirmed blunt liver trauma were studied retrospectively. Hospital folders of 311 patients were analysed. Information was gathered about the clinical presentation, associated injuries, grade of injury, transfusion requirements and haemodynamic stability to examine factors influencing outcome. RESULTS: The age of patients ranged between 3 weeks and 12 years (mean of 7 years). Injuries as a result of motor vehicle accidents (MVAs) were the most common (268; 232 pedestrian and 36 passenger), other causes were falls (26) assaults or child abuse(15), bicycle handle bar injury (2). One hundred and thirty-six patients sustained an isolated hepatic injury and 175 had multiple injuries. Associated injuries included 147 head injuries, 131 fractures, 66 thoracic and 143 intra-abdominal (74 spleen, 45 renal, 4 pancreatic and 4 hollow viscus). Two patients died soon after arrival, 21 underwent laparotomy, 13 of which were liver related, while 288 were treated non-operatively. One hundred and six patients required blood transfusion (mean of 21.3 ml/kg); 30% of the nonoperative group and 100% of the operative group. There were three fatalities from the operative group (1% total mortality), one secondary to a severe, head injury, one liver haemorrhage and one from multi-organ failure DISCUSSION: The vast majority (93%) was successfully treated non-operatively with only 4% coming to liver related laparotomy, complications were lower, transfusions less and the in-hospital occupancy was shorter. Complication rate was 8% and mortality was 1%. CONCLUSION: We confirm the success selective non-operative management of blunt liver trauma as adopted by this institution 20 years ago. It is now proven treatment in an appropriate centre. However, the challenge is to identify the severely injured child early and institute aggressive resuscitation and expedite laparotomy when indicated.

Fas-beyond death: a regenerative role for Fas in the nervous system.

Fas (CD95, APO-1), a member of the TNF superfamily, is a prototypical "death receptor" which transduces apoptotic signals in a variety of cell types. However, cell death is not the only possible outcome of Fas signalling. Fas engagement by Fas Ligand can also trigger proliferation or differentiation, promote tumour progression and angiogenesis, and induce cytokine secretion and integrin expression. Recently, we have reported that Fas engagement induces a potent regenerative response in sensory neurons in vitro, and enhances peripheral nerve regeneration in vivo. In contrast, other types of neurons, notably motoneurons, are acutely sensitive to Fas-induced apoptosis. Here, we review the literature on non-apoptotic Fas signalling pathways, and discuss the potential roles, molecular mechanisms, and regulators of Fas signalling in the nervous system.

A cytoplasmically inherited mutant controlling early chloroplast development in barley seedlings.

Cytoplasmic line 2 (CL2) has been previously reported as a cytoplasmically inherited chlorophyll-deficient mutant selected from a chloroplast-mutator genotype of barley. It was characterized by a localized effect on the upper part of the first-leaf blade. At emergence the CL2 seedlings-phenotype varied from a grainy light green to an albino color. They gradually greened during the following days, starting from the base of the blade and extending to cover most of its surface when it was fully grown. The present results, from both light microscopy and transmission electron microscopy (TEM), confirmed the previously described positional and time-dependent expression of the CL2 syndrome along the first-leaf blade. During the first days after emergence, light microscopy showed a normally developed chloroplast at the middle part of the CL2 first-leaf blade, meanwhile at the tip only small plastids were observed. TEM showed that the shapes and the internal structure of the small plastids were abnormal, presenting features of proplastids, amyloplasts and/or senescent gerontoplasts. Besides, they lack plastid ribosomes, contrasting with what was observed inside chloroplasts from normal tips, which presented abundant ribosomes. Phenotypic observations and spectrophotometric analysis of seedlings produced by mother plants that had been grown under different temperatures indicated that higher temperatures during seed formation were negatively associated with pigment content in CL2 seedlings. In contrast, higher temperatures during the growth of CL2 seedlings have been associated with increased pigment content. Aqueous solution with kanamycin and streptomycin, which are antibiotics known to interfere with plastid gene translation, were used for imbibition of wild-type and CL2 seeds. Antibiotic treatments differentially reduced the chlorophyll content in the upper part of the first-leaf blade in CL2, but not in wild-type seedlings. These results suggest that in the wild-type, plastid-gene proteins which are necessary for chloroplast development and chlorophyll synthesis in the upper part of the first-leaf blade are usually synthesized during embryogenesis. However, under certain circumstances, in CL2 seedlings, they would be synthesized after germination. In addition, a shortening of the sheath has been observed in association with pigment decrease suggesting the existence of plastid factors affecting the expression of some nuclear genes. We consider the CL2 mutant a unique experimental material useful to study biological phenomena and external factors regulating plastid, and nuclear gene expression during embryogenesis and early seedling development.

Long-term efficacy of combination therapy with interferon-alpha 2b and ribavirin for severe chronic hepatitis C in HIV-infected patients.

BACKGROUND: We have assessed the long-term efficacy and safety of a combination therapy of interferon alpha-2b (IFN) and ribavirin (RBV) for the treatment of severe chronic hepatitis C in co-infected HIV-seropositive patients in an open prospective study. METHODS: Fifty-one patients were treated for 12 months. Mean baseline CD4 cell count, alanine aminotransferase and aspartate aminotransferase were 412 +/- 232 x 106/l, 113 +/- 75 IU/l and 111 +/- 84 IU/l respectively. The mean Knodell score was 11.5 +/- 2.1 with 28 patients (55%) exhibiting histological evidence of active cirrhosis. RESULTS: Fifteen (29%) patients discontinued the treatment prematurely because of adverse events. An end of treatment response (ETR) as defined by the lack of detectable hepatitis C virus (HCV) RNA in plasma at the end of treatment was achieved in 15 patients (29%). A sustained virological response (SVR), defined by the lack of detectable HCV RNA in plasma 6 months after completion of combination therapy, was achieved in 11 patients (21%). The HCV genotype 3a was associated with ETR and SVR (P = 0.002 and P = 0.003, respectively). HCV viraemia at baseline was lower in patients who achieved SVR and ETR than in those who did not (6.7 +/- 7.8 versus 24 +/- 26.7 x 10(6) genome equivalents/ml, P = 0.03 and 14.3 +/- 28.7 versus 22.5 +/- 23, P = 0.05, respectively). CONCLUSION: Our results indicate that combination therapy with IFN and RBV is effective in approximately 20% of co-infected patients with severe liver disease.

Safety and efficacy of interferon-ribavirin combination therapy in HCV-HIV coinfected subjects: an early report.

BACKGROUND: More severe liver disease together with a poor response rate to alpha interferon argue for the use of more potent anti-hepatitis C virus (HCV) therapies in human immunodeficiency virus (HIV)-HCV coinfected patients, but the efficacy and safety of interferon-ribavirin combination therapy in HIV infected subjects are unknown. AIM: To retrospectively evaluate the efficacy and safety of anti-HCV combination therapy in 21 HCV-HIV coinfected patients receiving antiretroviral therapy, and to access the clinical relevance of in vitro inhibition of phosphorylation by ribavirin of potent inhibitors of HIV-that is, zidovudine, stavudine, and zalcitabine. PATIENTS: Twenty one patients were treated with combined antiretroviral therapy including zidovudine (n=8) or stavudine (n=13) (in association with protease inhibitors in 12). All received ribavirin (1000 or 1200 mg/day) and alpha interferon (3 MU three times/week) for chronic hepatitis C infection. All patients had not responded (n=20) or relapsed (n=1) after a previous six month course of alpha interferon therapy. METHODS: HIV viral load (Monitor test) and CD4 cells count were measured at the beginning and every three months during and after ribavirin plus alpha interferon therapy over a mean period of 11 (1) months. Clinical and biological adverse effects were recorded. RESULTS: There was no significant variation in HIV viral load or CD4 cell counts after three or six months of ribavirin therapy compared with baseline values. Of the 21 subjects, three (14%) had an increase in HIV viral load of more than 0.5 log leading to discontinuation of ribavirin in one. Eleven of 21 (52.4%) had initial negative HCV viraemia at three (n=10) or six (n=1) months but only six were polymerase chain reaction negative at the end of therapy, leading to rates for primary response and breakthrough of 23.8% and 28.5%, respectively. Six months after completion of therapy, three patients relapsed (14. 3%) and three (14.3%) had sustained virological response. Median haemoglobin concentration decreased significantly after three and six months of ribavirin therapy (p= 0.0002 and p=0.0003, respectively) leading to withdrawal of therapy in one patient. CONCLUSIONS: These preliminary results show that: (1) despite in vitro interactions between ribavirin, zidovudine, and stavudine, significant variation in HIV replication does not usually occur in HCV-HIV coinfected patients receiving ribavirin and different antiretroviral regimens, including zidovudine and stavudine; (2) alpha interferon and ribavirin combination therapy induced primary and sustained virological responses in 28.5% and 14.3% of treated subjects (who were previous non-responders to interferon therapy), respectively; (3) anaemia is a frequent adverse event. Such results should be confirmed in larger prospective trials.

Efficacy and safety of combination therapy with interferon-alpha2b and ribavirin for chronic hepatitis C in HIV-infected patients.

OBJECTIVES: To evaluate the efficacy and safety of a combination therapy of interferon-alpha2b (IFN) and ribavirin for the treatment of chronic hepatitis C in HIV-seropositive patients. DESIGN: Open prospective trial. METHODS: Twenty patients co-infected with hepatitis C virus (HCV) and HIV, with a mean CD4 cell count of 350 +/- 153 x 10(6)/l were treated with IFN (3 MU three times per week) in combination with ribavirin (500 mg or 600 mg twice a day) for 6 months. Tolerance and efficacy were monitored at weeks 12 (month 3) and 24 (month 6). The primary endpoint was a complete virological response, as defined by the lack of detectable HCV RNA in serum. RESULTS: Baseline values of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were 121 +/- 72 IU/l and 75 +/- 67 IU/l, respectively. The total Knodell score was 10.4 +/- 2.4, with nine patients showing histological evidence of active cirrhosis (45%). All patients exhibited circulating HCV RNA. The treatment was well tolerated, with no impact on the course of HIV infection. After 6 months of combination therapy with IFN and ribavirin, 10 patients (50%) exhibited no further detectable HCV RNA viraemia, seven of whom achieved undetectable viraemia at month 3. Levels of ALT and AST decreased after 6 months of treatment from a mean of 121 +/- 72 to 51 +/- 40 IU/l and from a mean of 129 +/- 58 IU/l to 68 +/- 61 IU/l, respectively (P < 0.0002 and P < 0.0001). CONCLUSION: Our results indicate that combination therapy with IFN and ribavirin is effective in 50% of cases in clearing serum HCV RNA and may thus provide effective means of therapy in HIV-HCV-coinfected patients as initial treatment or in patients who have previously failed IFN monotherapy.

Delay in opening the infarct related coronary artery increases plasma atrial natriuretic peptide levels.

Plasma atrial natriuretic peptide (ANP) levels were measured in rabbits during the late healing phase of myocardial infarcts. Significant differences in plasma ANP levels (P < 0.02) were found between rabbits that had undergone very late (6 h) or early reperfusion (20 and 45 min of ischemia) of the infarct related coronary artery. Differences in ANP levels were independent of infarct size, ventricular remodeling and infarct expansion. We conclude late reperfusion of infarct related artery, independent of myocardial salvage, is associated with increased circulating ANP plasma levels.

Rapidly evolving hepatitis C virus-related cirrhosis in a human immunodeficiency virus-infected patient receiving triple antiretroviral therapy.

Triple antiretroviral therapy combining reverse transcriptase and protease inhibitors modifies the prognosis of human immunodeficiency virus (HIV) infection, with dramatic improvement in immune status. The precise impact, if any, of anti-HIV triple therapy on hepatitis C virus (HCV) infection is unknown. We describe an unusual case of rapidly evolving HCV-related cirrhosis that paralleled restoration of immune status in an HIV-infected patient and discuss the possible link between such a severe course of hepatitis C and anti-HIV triple therapy.