779 research outputs found
Pelvic actinomycosis presenting as a malignant pelvic mass: a case report
<p>Abstract</p> <p>Introduction</p> <p>Pelvic actinomycosis constitutes 3% of all human actinomycosis infections. It is usually insidious, and is often mistaken for other conditions such as diverticulitis, abscesses, inflammatory bowel disease and malignant tumors, presenting a diagnostic challenge pre-operatively; it is identified post-operatively in most cases. Here we present a case that presented as pelvic malignancy and was diagnosed as pelvic actinomycosis post-operatively.</p> <p>Case presentation</p> <p>A 48-year-old Caucasian Turkish woman presented to our clinic with a three-month history of abdominal pain, weight loss and difficulty in defecation. She had used an intra-uterine device for 16 years, however it had recently been removed. The rectosigmoidoscopy revealed narrowing of the lumen at 12 cm due to a mass lesion either in the wall or due to an extrinsic lesion that prevented the passage of the endoscope. On examination, there was no gynecological pathology. Magnetic resonance imaging showed a mass, measuring 5.5 × 4 cm attached to the rectum posterior to the uterus. The ureter on that side was dilated. Surgically there was a pelvic mass adhered to the rectum and uterine adnexes, measuring 10 × 12 cm. It originated from uterine adnexes, particularly ones from the left side and formed a conglomerated mass with the uterus and nearby organs; the left ureter was also dilated due to the pelvic mass. Because of concomitant tubal abscess formation and difficulty in dissection planes, total abdominal hysterectomy and bilateral salphingo-oophorectomy was performed (our patient was 48 years old and had completed her childbearing period). The cytology revealed inflammatory cells with aggregates of <it>Actinomyces</it>. Penicillin therapy was given for six months without any complication.</p> <p>Conclusions</p> <p>Pelvic actinomycosis should always be considered in patients with a pelvic mass especially in ones using intra-uterine devices, and who have a history of appendectomy, tonsillectomy or dental infection. Surgeons should be aware of this infection in order to avoid excessive surgical procedures.</p
Observation of squeezed light from one atom excited with two photons
Single quantum emitters like atoms are well-known as non-classical light
sources which can produce photons one by one at given times, with reduced
intensity noise. However, the light field emitted by a single atom can exhibit
much richer dynamics. A prominent example is the predicted ability for a single
atom to produce quadrature-squeezed light, with sub-shot-noise amplitude or
phase fluctuations. It has long been foreseen, though, that such squeezing
would be "at least an order of magnitude more difficult" to observe than the
emission of single photons. Squeezed beams have been generated using
macroscopic and mesoscopic media down to a few tens of atoms, but despite
experimental efforts, single-atom squeezing has so far escaped observation.
Here we generate squeezed light with a single atom in a high-finesse optical
resonator. The strong coupling of the atom to the cavity field induces a
genuine quantum mechanical nonlinearity, several orders of magnitude larger
than for usual macroscopic media. This produces observable quadrature squeezing
with an excitation beam containing on average only two photons per system
lifetime. In sharp contrast to the emission of single photons, the squeezed
light stems from the quantum coherence of photon pairs emitted from the system.
The ability of a single atom to induce strong coherent interactions between
propagating photons opens up new perspectives for photonic quantum logic with
single emittersComment: Main paper (4 pages, 3 figures) + Supplementary information (5 pages,
2 figures). Revised versio
Caveats of chronic exogenous corticosterone treatments in adolescent rats and effects on anxiety-like and depressive behavior and hypothalamic-pituitary-adrenal (HPA) axis function
<p>Abstract</p> <p>Background</p> <p>Administration of exogenous corticosterone is an effective preclinical model of depression, but its use has involved primarily adult rodents. Using two different procedures of administration drawn from the literature, we explored the possibility of exogenous corticosterone models in adolescence, a time of heightened risk for mood disorders in humans.</p> <p>Methods</p> <p>In experiment 1, rats were injected with 40 mg/kg corticosterone or vehicle from postnatal days 30 to 45 and compared with no injection controls on behavior in the elevated plus maze (EPM) and the forced swim test (FST). Experiment 2 consisted of three treatments administered to rats from postnatal days 30 to 45 or as adults (days 70 to 85): either corticosterone (400 μg/ml) administered in the drinking water along with 2.5% ethanol, 2.5% ethanol or water only. In addition to testing on EPM, blood samples after the FST were obtained to measure plasma corticosterone. Analysis of variance (ANOVA) and alpha level of <it>P </it>< 0.05 were used to determine statistical significance.</p> <p>Results</p> <p>In experiment 1, corticosterone treatment of adolescent rats increased anxiety in the EPM and decreased immobility in the FST compared to no injection control rats. However, vehicle injected rats were similar to corticosterone injected rats, suggesting that adolescent rats may be highly vulnerable to stress of injection. In experiment 2, the intake of treated water, and thus doses delivered, differed for adolescents and adults, but there were no effects of treatment on behavior in the EPM or FST. Rats that had ingested corticosterone had reduced corticosterone release after the FST. Ethanol vehicle also affected corticosterone release compared to those ingesting water only, but differently for adolescents than for adults.</p> <p>Conclusions</p> <p>The results indicate that several challenges must be overcome before the exogenous corticosterone model can be used effectively in adolescents.</p
Financial considerations in the conduct of multi-centre randomised controlled trials: evidence from a qualitative study.
National Coordinating Centre for Research Methodology; Medical Research Council, UK Department of Health; Chief Scientist OfficeNot peer reviewedPublisher PD
Electrophysiological Heterogeneity of Fast-Spiking Interneurons: Chandelier versus Basket Cells
In the prefrontal cortex, parvalbumin-positive inhibitory neurons play a prominent role in the neural circuitry that subserves working memory, and alterations in these neurons contribute to the pathophysiology of schizophrenia. Two morphologically distinct classes of parvalbumin neurons that target the perisomatic region of pyramidal neurons, chandelier cells (ChCs) and basket cells (BCs), are generally thought to have the same "fast-spiking" phenotype, which is characterized by a short action potential and high frequency firing without adaptation. However, findings from studies in different species suggest that certain electrophysiological membrane properties might differ between these two cell classes. In this study, we assessed the physiological heterogeneity of fast-spiking interneurons as a function of two factors: species (macaque monkey vs. rat) and morphology (chandelier vs. basket). We showed previously that electrophysiological membrane properties of BCs differ between these two species. Here, for the first time, we report differences in ChCs membrane properties between monkey and rat. We also found that a number of membrane properties differentiate ChCs from BCs. Some of these differences were species-independent (e.g., fast and medium afterhyperpolarization, firing frequency, and depolarizing sag), whereas the differences in the first spike latency between ChCs and BCs were species-specific. Our findings indicate that different combinations of electrophysiological membrane properties distinguish ChCs from BCs in rodents and primates. Such electrophysiological differences between ChCs and BCs likely contribute to their distinctive roles in cortical circuitry in each species. © 2013 Povysheva et al
Cognitive impairment induced by delta9-tetrahydrocannabinol occurs through heteromers between cannabinoid CB1 and serotonin 5-HT2A receptors
Delta-9-tetrahydrocannabinol (THC), the main psychoactive compound of marijuana, induces numerous undesirable effects, including memory impairments, anxiety, and dependence. Conversely, THC also has potentially therapeutic effects, including analgesia, muscle relaxation, and neuroprotection. However, the mechanisms that dissociate these responses are still not known. Using mice lacking the serotonin receptor 5-HT2A, we revealed that the analgesic and amnesic effects of THC are independent of each other: while amnesia induced by THC disappears in the mutant mice, THC can still promote analgesia in these animals. In subsequent molecular studies, we showed that in specific brain regions involved in memory formation, the receptors for THC and the 5-HT2A receptors work together by physically interacting with each other. Experimentally interfering with this interaction prevented the memory deficits induced by THC, but not its analgesic properties. Our results highlight a novel mechanism by which the beneficial analgesic properties of THC can be dissociated from its cognitive side effects
Development of a Multivalent Subunit Vaccine against Tularemia Using Tobacco Mosaic Virus (TMV) Based Delivery System
Francisella tularensisis a facultative intracellular pathogen, and is the causative agent of a fatal human disease known as tularemia. F. tularensis is classified as a Category A Biothreat agent by the CDC based on its use in bioweapon programs by several countries in the past and its potential to be used as an agent of bioterrorism. No licensed vaccine is currently available for prevention of tularemia. In this study, we used a novel approach for development of a multivalent subunit vaccine against tularemia by using an efficient tobacco mosaic virus (TMV) based delivery platform. The multivalent subunit vaccine was formulated to contain a combination of F. tularensis protective antigens: OmpA-like protein (OmpA), chaperone protein DnaK and lipoprotein Tul4 from the highly virulent F. tularensisSchuS4 strain. Two different vaccine formulations and immunization schedules were used. The immunized mice were challenged with lethal (10xLD100) doses of F. tularensisLVS on day 28 of the primary immunization and observed daily for morbidity and mortality. Results from this study demonstrate that TMV can be used as a carrier for effective delivery of multiple F. tularensisantigens. TMV-conjugate vaccine formulations are safe and multiple doses can be administered without causing any adverse reactions in immunized mice. Immunization with TMV-conjugated F. tularensisproteins induced a strong humoral immune response and protected mice against respiratory challenges with very high doses of F. tularensis LVS. This study provides a proof-of-concept that TMV can serve as a suitable platform for simultaneous delivery of multiple protective antigens of F. tularensis. Refinement of vaccine formulations coupled with TMV-targeting strategies developed in this study will provide a platform for development of an effective tularemia subunit vaccine as well as a vaccination approach that may broadly be applicable to many other bacterial pathogens
Lessons from SARS: A retrospective study of outpatient care during an infectious disease outbreak
<p>Abstract</p> <p>Background</p> <p>During severe acute respiratory syndrome (SARS) outbreak in Toronto, outpatient clinics at SickKids Hospital were closed to prevent further disease transmission. In response, a decision was made by the neonatal neuro-developmental follow up (NNFU) clinic staff to select patients with scheduled appointments to have a mail/telephone assessment using Ages and Stages Questionnaire (ASQ) or to postpone/skip their visit. The objective of this study was to compare the developmental assessment and its outcome in two groups of NNFU clinic patients, SARS versus non-SARS, over three standard clinic appointments.</p> <p>Methods</p> <p>We compared the diagnostic accuracy (identification of developmental delay), and patient management (referral for therapy or communication of a new diagnosis) of the strategies used during SARS, April/May 2003, to the standard assessment methods used for patients seen in April/May 2005 (non-SARS). In all cases data were obtained for 3 patient visits: before, during and after these 2 months and were compared using descriptive statistics.</p> <p>Results</p> <p>There were 95 patients in the SARS group and 99 non-SARS patients. The gestational age, sex, entry diagnosis and age at the clinic visit was not different between the groups. The NNFU clinic staff mailed ASQ to 27 families during SARS, 17 (63%) were returned, and 8 of the 17 were then contacted by telephone. Criteria used to identify infants at risk selected for either mailed ASQ or phone interviews were not clearly defined in the patients' charts. There was a significant under identification of developmental delay during SARS (18% versus 45%). Of those who responded to the mailed questionnaire, referrals for therapy rates were similar to non-SARS group. The lost to follow up rate was 24% for the SARS group compared with 7% for non-SARS. There was no difference in the overall rate of developmental delay in the two groups as identified at the 'after' visit.</p> <p>Conclusions</p> <p>Poor advanced planning led to a haphazard assessment of patients during this infectious disease outbreak. Future pandemic plans should consider planning for outpatient care as well as in hospital management of patients.</p
The biogeography of the atlantic salmon (Salmo salar) gut microbiome
Although understood in many vertebrate systems, the natural diversity of host-associated microbiota has been little studied in teleosts. For migratory fishes, successful exploitation of multiple habitats may affect and be affected by the composition of the intestinal microbiome. We collected 96 Salmo salar from across the Atlantic encompassing both freshwater and marine phases. Dramatic differences between environmental and gut bacterial communities were observed. Furthermore, community composition was not significantly impacted by geography. Instead life-cycle stage strongly defined both the diversity and identity of microbial assemblages in the gut, with evidence for community destabilisation in migratory phases. Mycoplasmataceae phylotypes were abundantly recovered in all life-cycle stages. Patterns of Mycoplasmataceae phylotype recruitment to the intestinal microbial community among sites and life-cycle stages support a dual role for deterministic and stochastic processes in defining the composition of the S. salar gut microbiome
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