432 research outputs found

    In vitro co-culture and ex vivo organ culture assessment of primed and cryopreserved stromal cell microcapsules for intervertebral disc regeneration

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    Priming towards a discogenic phenotype and subsequent cryopreservation of microencapsulated bone marrow stromal cells (BMSCs) may offer an attractive therapeutic approach for disc repair. It potentially obviates the need for in vivo administration of exogenous growth factors, otherwise required to promote matrix synthesis, in addition to providing 'off-the-shelf' availability. Cryopreserved and primed BMSC microcapsules were evaluated in an in vitro surrogate co-culture model system with nucleus pulposus (NP) cells under intervertebral disc (IVD)-like culture conditions and in an ex vivo bovine organ culture disc model. BMSCs were microencapsulated in alginate microcapsules and primed for 14 d with transforming growth factor beta-3 (TGF-β3) under low oxygen conditions prior to cryopreservation. For the in vitro phase, BMSC microcapsules (unprimed or primed) were cultured for 28 d in a surrogate co-culture model system mimicking that of the IVD. For the ex vivo phase, microcapsules (unprimed or primed) were injected into the NP of bovine discs that underwent nucleotomy. In vitro results revealed that although NP cells produced significantly more matrix components in co-culture with BMSC microcapsules regardless of the differentiation state, unprimed microcapsules were inadequate at synthesising matrix as compared to primed microcapsules. However, this difference was diminished when evaluated in the ex vivo organ culture model,withboth unprimed and primed BMSC microcapsules accumulating large amounts of sulphated glycosaminoglycan (sGAG) and collagen and filling the defect cavity. Both models demonstrated that cryopreservation of BMSC microcapsules may offer a feasible strategy for predesigned delivery through cryobanking for on-demand regeneration of the IVD

    Acute ST segment elevation during exercise stress echocardiography due to severe pulmonary hypertension

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    A 51-year-old female undergoing an outpatient stress echocardiogram to evaluate atypical chest pain developed acute ST elevation in the anterior precordial leads on electrocardiogram following exercise. Echocardiography revealed a severe rise in pulmonary artery systolic pressure (PASP) with marked right ventricular (RV) enlargement and interventricular septum flattening. Subsequently, cardiac catherization confirmed an exercise-induced elevation in PASP and diagnosed pulmonary arterial hypertension without evidence of coronary artery disease. This case suggests that an acute elevation in pulmonary artery pressure with RV dilation may be a potential cause of acute ST elevation during stress testing

    Educating and Informing Patients Receiving Psychopharmacological Medications: Are Family Physicians in Pakistan up to the Task?

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    Introduction: Studies have shown a high prevalence of psychiatric illnesses among Patients in primary health care settings. Family physicians have a fundamental role in managing psychiatric illness with psychopharmacological medications. Providing information about the disease, its management and the potential adverse effects of the medications is an important part of the management of mental illnesses. Our objective was to determine if Patients who were prescribed psychopharmacological drugs by family physicians at a community health center in Karachi, Pakistan were provided adequate education about their disease and its management. Methods: A cross-sectional study was conducted at the Community Health Centre (CHC), Aga Khan University Hospital Karachi, Pakistan. Details about the prescriptions and Patient education were acquired from the Patients after their consultations. Results: A total of 354 adult Patients were interviewed during 3 days. Among them, 73 (20.6%) were prescribed psychopharmacological medications. Among Patients receiving psychopharmacological medicines, 37 (50.7%) did not know their diagnosis, 50 (68.5%) were unaware of the disease process, 52 (71.2%) were unaware of alternative treatments, 63 (86.3%) were not cautioned about the potential adverse effects of the drugs, 24 (32.9%) were unaware of the duration of treatment and in 60 (82.2%) of the participants an appropriate referral had not been discussed. For all aspects of education, Patients prescribed psychopharmacological medications knew less as compared to those Patients that were prescribed other medications. Discussion: The practice of imparting information to Patients who receive psychopharmacological medications seems to be inadequate in Pakistan. We have hypothesized about the possible reasons for our findings, and identified a need for further research to determine the cause for such findings and to address them accordingly. At the same time there is a need to educate family physicians in Pakistan about the special importance of providing adequate information to such Patients

    Sr-Nd isotope geochemistry of the early Precambrian sub-alkaline mafic igneous rocks from the southern Bastar craton, Central India

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    Sr–Nd isotope data are reported for the early Precambrian sub-alkaline mafic igneous rocks of the southern Bastar craton, central India. These mafic rocks are mostly dykes but there are a few volcanic exposures. Field relationships together with the petrological and geochemical characteristics of these mafic dykes divide them into two groups; Meso-Neoarchaean sub-alkaline mafic dykes (BD1) and Paleoproterozoic (1.88 Ga) sub-alkaline mafic dykes (BD2). The mafic volcanics are Neoarchaean in age and have very close geochemical relationships with the BD1 type. The two groups have distinctly different concentrations of high-field strength (HFSE) and rare earth elements (REE). The BD2 dykes have higher concentrations of HFSE and REE than the BD1 dykes and associated volcanics and both groups have very distinctive petrogenetic histories. These rocks display a limited range of initial 143Nd/144Nd but a wide range of apparent initial 87Sr/86Sr. Initial 143Nd/144Nd values in the BD1 dykes and associated volcanics vary between 0.509149 and 0.509466 and in the BD2 dykes the variation is between 0.510303 and 0.510511. All samples have positive εNd values the BD1 dykes and associated volcanics have εNd values between +0.3 and +6.5 and the BD2 dykes between +1.9 to +6.0. Trace element and Nd isotope data do not suggest severe crustal contamination during the emplacement of the studied rocks. The positive εNd values suggest their derivation from a depleted mantle source. Overlapping positive εNd values suggest that a similar mantle source tapped by variable melt fractions at different times was responsible for the genesis of BD1 (and associated volcanics) and BD2 mafic dykes. The Rb–Sr system is susceptible to alteration and resetting during post-magmatic alteration and metamorphism. Many of the samples studied have anomalous apparent initial 87Sr/86Sr suggesting post-magmatic changes of the Rb–Sr system which severely restricts the use of Rb–Sr for petrogenetic interpretation

    Under pressure: Response urgency modulates striatal and insula activity during decision-making under risk

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    When deciding whether to bet in situations that involve potential monetary loss or gain (mixed gambles), a subjective sense of pressure can influence the evaluation of the expected utility associated with each choice option. Here, we explored how gambling decisions, their psychophysiological and neural counterparts are modulated by an induced sense of urgency to respond. Urgency influenced decision times and evoked heart rate responses, interacting with the expected value of each gamble. Using functional MRI, we observed that this interaction was associated with changes in the activity of the striatum, a critical region for both reward and choice selection, and within the insula, a region implicated as the substrate of affective feelings arising from interoceptive signals which influence motivational behavior. Our findings bridge current psychophysiological and neurobiological models of value representation and action-programming, identifying the striatum and insular cortex as the key substrates of decision-making under risk and urgency

    Gustatory Imagery Reveals Functional Connectivity from the Prefrontal to Insular Cortices Traced with Magnetoencephalography

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    Our experience and prejudice concerning food play an important role in modulating gustatory information processing; gustatory memory stored in the central nervous system influences gustatory information arising from the peripheral nervous system. We have elucidated the mechanism of the 'top-down" modulation of taste perception in humans using functional magnetic resonance imaging (fMRI) and demonstrated that gustatory imagery is mediated by the prefrontal (PFC) and insular cortices (IC). However, the temporal order of activation of these brain regions during gustatory imagery is still an open issue. To explore the source of "top-down" signals during gustatory imagery tasks, we analyzed the temporal activation patterns of activated regions in the cerebral cortex using another non-invasive brain imaging technique, magnetoencephalography (MEG). Gustatory imagery tasks were presented by words (Letter G-V) or pictures (Picture G-V) of foods/beverages, and participants were requested to recall their taste. In the Letter G-V session, 7/9 (77.8%) participants showed activation in the IC with a latency of 401.7 +/- 34.7 ms (n = 7) from the onset of word exhibition. In 5/7 (71.4%) participants who exhibited IC activation, the PFC was activated prior to the IC at a latency of 315.2 +/- 56.5 ms (n = 5), which was significantly shorter than the latency to the IC activation. In the Picture G-V session, the IC was activated in 6/9 (66.7%) participants, and only 1/9 (11.1%) participants showed activation in the PFC. There was no significant dominance between the right and left IC or PFC during gustatory imagery. These results support those from our previous fMRI study in that the Letter G-V session rather than the Picture G-V session effectively activates the PFC and IC and strengthen the hypothesis that the PFC mediates "top-down" control of retrieving gustatory information from the storage of long-term memories and in turn activates the IC

    Awareness and perceptions of electroconvulsive therapy among psychiatric patients: a cross-sectional survey from teaching hospitals in Karachi, Pakistan

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    <p>Abstract</p> <p>Background</p> <p>Electroconvulsive therapy (ECT) is shown to be effective in many psychiatric illnesses, but its distorted projection by the Pakistani media and its unregulated use by many physicians across the country have adversely affected its acceptability. Given this situation we aimed to assess the awareness and perceptions regarding ECT as a treatment modality among the psychiatric patients.</p> <p>Methods</p> <p>This was a questionnaire based cross-sectional study carried out at 2 tertiary care hospitals in Karachi, Pakistan.</p> <p>Results</p> <p>We interviewed 190 patients of which 140 were aware of ECT. The study showed that the level of education had a significant impact on the awareness of ECT (p = 0.009). The most common source of awareness was electronic and print media (38%), followed by relatives (24%) and doctors (23%). Physical injuries (42%) and neurological (12%) and cognitive disturbances (11%) were the commonly feared side effects. The most popular belief about ECT was that it was a treatment of last resort (56%). Thirty-nine percent thought that ECT could lead to severe mental and physical illness and 37% considered it inhumane. Patients' willingness to receive ECT was dependant on whether or not they were convinced of its safety (p = 0.001) and efficacy (p = 0.0001).</p> <p>Conclusion</p> <p>We identified a serious lack of dissemination of information regarding ECT by the psychiatrists and the mental health care providers. This may be the result of an inadequate postgraduate training in Pakistan or just a lack of concern about the mentally ill patients. The media seemed to be the major source of information for our patients. We also saw the prevalence of a variety of myths regarding ECT in our society, which we feel may be responsible for the patients' adverse attitudes. Given the widespread applicability of ECT there is a dire need to dispel these misconceptions and improve its acceptability.</p
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