Alias-free, real coefficient m-band QMF banks for arbitrary m

Based on a generalized framework for alias free QMF banks, a theory is developed for the design of uniform QMF banks with real-coefficient analysis filters, such that aliasing can be completely canceled by appropriate choice of real-coefficient synthesis filters. These results are then applied for the derivation of closed-form expressions for the synthesis filters (both FIR and IIR), that ensure cancelation of aliasing for a given set of analysis filters. The results do not involve the inversion of the alias-component (AC) matrix

Theory and design of uniform DFT, parallel, quadrature mirror filter banks

In this paper, the theory of uniform DFT, parallel, quadrature mirror filter (QMF) banks is developed. The QMF equations, i.e., equations that need to be satisfied for exact reconstruction of the input signal, are derived. The concept of decimated filters is introduced, and structures for both analysis and synthesis banks are derived using this concept. The QMF equations, as well as closed-form expressions for the synthesis filters needed for exact reconstruction of the input signalx(n), are also derived using this concept. In general, the reconstructed. signalhat{x}(n)suffers from three errors: aliasing, amplitude distortion, and phase distortion. Conditions for exact reconstruction (i.e., all three distortions are zero, andhat{x}(n)is equal to a delayed version ofx(n))of the input signal are derived in terms of the decimated filters. Aliasing distortion can always be completely canceled. Once aliasing is canceled, it is possible to completely eliminate amplitude distortion (if suitable IIR filters are employed) and completely eliminate phase distortion (if suitable FIR filters are employed). However, complete elimination of all three errors is possible only with some simple, pathalogical stable filter transfer functions. In general, once aliasing is canceled, the other distortions can be minimized rather than completely eliminated. Algorithms for this are presented. The properties of FIR filter banks are then investigated. Several aspects of IIR filter banks are also studied using the same framework

Vasoplegic syndrome after off pump coronary artery bypass grafting surgery

We report a case of 48-years-old man who developed nor-epinephrine resistant vasoplegic syndrome after elective off pump coronary artery bypass grafting surgery. The failure of norepinephrine to improve the patients’ hemodynamics promted us to start treatment with vasopressin. Within an hour, the hemodynamics begin to improve. After 4 hours, patient was stable enough to be weaned from vasopressin, extubated at the end of 24 hrs and shifted to ward at the end of 48 hours. Vasoplegic syndrome can occur commonly after cardiopulmonary bypass and incidence can go up to 10%. This case was reported to insist upon the fact that vasoplegic syndrome can occur even after off pump surgeries. Herein we discuss the aetiology, risk factors, pathophysiology and prophylactic measures to be taken, for the prevention of vasoplegic syndrome

Diaphragmatic fenestration an effective treatment for refractory postoperative chylothorax: a case report

Postoperative chylothorax remains a clinical challenge to the surgeon with substantial morbidity and risk of mortality. Though an uncommon complication, it is known to complicate cardiac and non-cardiac thoracic surgeries. Conservative measures are first employed in managing this. Surgical options are adopted when the effusion is protracted, most recent of which includes diaphragmatic fenestration. A 9-year-old girl is presented who developed recurrent right chylothorax following thoracoscopic excision of a cystic lymphangioma. Following failed conservative therapy, she had thoracic duct ligation and right diaphragmatic fenestration (using fenestrated polytetrafluoroethylene patch) with satisfactory outcome. Aetio-pathologic mechanisms implicated in postoperative chylothorax have been classified into traumatic (iatrogenic injury to the thoracic duct or its branches) and non-traumatic. With initial conservative measures (repeated pleural aspirations and intercostal drainage, medium chain triglyceride/ low fat feeds or alternatively, fasting and total parenteral nutrition) spontaneous closure remains unpredictable. Diaphragmatic fenestration when employed resulted in faster resolution of effusion and earlier commencement of enteral feeding with no significant complication. Diaphragmatic fenestration is effective and safe for treating refractory post-operative chylothorax

Atrial myxoma invading right ventricular cavity and pulmonary artery

Study report a 42-years-old female came with complaints of dyspnoea on exertion, and recurrent cough for past one year. She gives history of significant weight loss for the past 6 months. Trans thoracic echocardiogram showed large pedunculated myxoma measuring 28*18 mm attached to posterior wall of right atrium extending into right ventricle and outflow tract. Computed tomography pulmonary angiogram showed acute bilateral pulmonary thromboembolism with left upper lobe infarct. She underwent complete removal of the tumour along with patch of atrial wall with pulmonary embolectomy using Fogarty baloon catheter through median sternotomy. Her postoperative course was uneventful. This case is reported for its rarity of presentation of right atrial myxoma with pulmonary embolism

Feasibility of Provider-Initiated HIV Testing and Counselling of Tuberculosis Patients Under the TB Control Programme in Two Districts of South India

BACKGROUND:Provider-initiated HIV testing and counselling (PITC) is internationally recommended for tuberculosis (TB) patients, but the feasibility, effectiveness, and impact of this policy on the TB programme in India are unknown. We evaluated PITC of TB patients across two districts in India considered to have generalized HIV epidemics, Tiruchirappalli (population 2.5 million) and Mysore (population 2.8 million). METHODOLOGY/PRINCIPAL FINDINGS:Starting June 2007, healthcare providers in both districts were instructed to ascertain HIV status for all TB patients, and refer those with unknown HIV status to the nearest Integrated Counselling and Testing Centre (ICTC)--often in the same facility--for counselling and voluntary HIV testing. All TB patients registered from June 2007 to March 2008 were followed prospectively. Field investigators assessed PITC practices and abstracted data from routine TB programme records and HIV counselling registers to determine the proportion of TB patients appropriately evaluated for HIV infection. Patient records were traced to determine the efficiency of referral links to HIV care and antiretroviral treatment (ART). Between July 2007 and March 2008, 5299 TB patients were registered in both study districts. Of the 4701 with unknown HIV status at the time of TB treatment initiation, 3368 (72%) were referred to an ICTC, and 3111 (66%) were newly tested for HIV. PITC implementation resulted in the ascertainment of HIV status for 3709/5299 (70%) of TB patients, and detected 200 cases with previously undiagnosed HIV infection. Overall, 468 (8.8%) of all registered TB patients were HIV-infected; 177 (37%) were documented to have also received any ART. CONCLUSIONS:With implementation of PITC in India, HIV status was successfully ascertained for 70% of TB patients. Previously undiagnosed HIV-infection was detected in 6.4% of those TB patients newly tested, enabling referral for life-saving anti-retroviral treatment. ART uptake, however, was poor, suggesting that PITC implementation should include measures to strengthen and support ART referral, evaluation, and initiation

Perceptions of Tuberculosis Patients on Provider-Initiated HIV Testing and Counseling - A Study from South India

Background: The acceptability and feasibility of provider-initiated HIV testing and counseling (PITC) in many settings across Asia with concentrated HIV epidemics is not known. A pilot study of the PITC policy undertaken within the public health care systems in two districts in India offered the opportunity to understand patient's perspectives on the process of referral for HIV testing and linking to HIV treatment and care. Methods: We conducted a cross-sectional study of randomly selected TB patients registered by the TB control program between July and November 2007 in two districts in south India. Trained interviewers met patients shortly after TB diagnosis and administered a structured questionnaire. Patients were assessed regarding their experience with HIV status assessment, referral for counseling and testing, and for HIV-infected patients the counseling itself and subsequent referral for HIV treatment and care. Results: Of the 568 interviewed TB patients, 455 (80%) reported being referred for HIV testing after they presented to the health facility for investigations or treatment for TB. Over half the respondents reported having to travel long distances and incurred financial difficulties in reaching the Integrated Counselling and Testing Centre (ICTC) and two-thirds had to make more than two visits. Only 48% reported having been counseled before the test. Of the 110 HIV-infected patients interviewed, (including 43 with previously-known positive HIV status and 67 detected by PITC), 89 (81%) reported being referred for anti-retroviral treatment (ART); 82 patients reached the ART centre but only 44 had been initiated on ART. Conclusions: This study provides the first evidence from India that routine, provider-initiated voluntary HIV testing of TB patients is acceptable, feasible and can be achieved with very high efficiency under programmatic conditions. While PITC is useful in identifying new HIV-infected patients so that they can be successfully linked to ART, the convenience and proximity of testing centres, quality of HIV counseling, and efficiency of ART services need attention

Bacterial Toxins and the Nervous System: Neurotoxins and Multipotential Toxins Interacting with Neuronal Cells

Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons

Is epidermal growth factor system dysfunction associated with schizophrenia subtypes?

© 2017 Dr Vaidyanathan SwaminathanSchizophrenia is a severe neuropsychiatric disorder characterised by positive symptoms such as delusions and hallucinations, negative symptoms such as amotivation and asociality and cognitive symptoms such as working memory and processing speed deficits. It is also accompanied by consequential clinical features and paradigms such as suicidality and treatment resistance. Clozapine, an atypical antipsychotic medication, mitigates suicidality and is efficacious in treatment resistance. The unique actions of clozapine may be due to its ability, but not other anti-psychotic medications, to recruit the Epidermal Growth Factor (EGF)/EGF Receptor (EGFR) signalling system. In this thesis, we used post mortem brain samples from the dorsolateral prefrontal cortex (DLPFC) of 37 individuals with schizophrenia and 37 without the disorder, who were a matched cohort. We utilized quantitative PCR to examine the EGF receptor. Then, to establish the distribution and localisation of EGFR in schizophrenia, we supplemented our quantitative studies with protein assays for the EGFR protein and in situ hybridization followed by autoradiography for EGFR mRNA. In order to then examine the relationship of cognitive functioning in schizophrenia and the EGF/EGFR signalling molecules, we examined the cognitive profile of 449 persons with schizophrenia and 637 control participants from the Australian Schizophrenia Research Bank database. We also examined if the cognitive performance in schizophrenia cluster to inform disorder sub typing and subsequently explored the relationship of cognition in schizophrenia to EGF/EGFR genomic signals by way of a candidate gene approach. In our studies, we found that EGFR protein levels are significantly increased in the DLPFC of persons with schizophrenia, although, there were no mRNA expression differences. The older neopallidal layers of the cortex showed that participants who had died of non-suicide had lower EGFR mRNA expression. Similarly, those without a history of suicide attempts showed a decreased mRNA expression more widely in the neopallidal layers. We also showed layer specific changes in relation to a number of clinical features in schizophrenia. In comparison to all other previous studies, we showed a case control difference without the need for stratification that persons who carry the AA genotype of the EGF A61G single nucleotide polymorphism (SNP), are more likely to have schizophrenia. We also showed that there are three clusters of cognitive performance within schizophrenia and treatment resistance and 2 NRG1 SNPs associate with various cluster memberships significantly. Our results show evidence to support the role of EGF/EGFR signalling in mediating and moderating several clinical parameters in schizophrenia such as treatment resistance, suicidality and cognitive functioning. We also have identified a relationship between EGF/EGFR signalling system hypofunction and schizophrenia and propose that clozapine may augment this signalling thereby mitigating this hypofunctional state. Together, these results may offer further insights into the relationship between the EGF signalling system, cognition and clinical features of schizophrenia and allow for development of novel biomarker strategies to identify early at-risk patients