Karachi, Pakistan
Karachi, Pakistan

The University of Karachi is a public research university located in the neighborhood of Gulshan-e-Iqbal of Karachi, Sindh, Pakistan. It is one of the oldest universities in Pakistan and ranked among the top ten universities of the country in terms of the international standard, according to the Higher Education Commission in 2013. In 2009, the university successfully entered its name in the THE-QS World University Rankings for the top 500 universities in the world. World renowned and notable scholars have been associated and affiliated with the university as faculty, researchers, or alumni since its establishment. The university offers wide range of undergraduate and graduate degree programs and more than 19 world-class research institutes are under the university in all over Karachi.With an approximated of more than 80,000 students currently attending the university, the KU is the university with the largest nation-wide enrollment as well as the most popular university in Pakistan and abroad by the number of applicants. The university is also a member of Association of Commonwealth Universities of the United Kingdom.The Karachi University holds a unique position in the country's educational system and is distinguished reputation for conducting multi-disciplinary research in science and technology, medical research, and social science. As a respected research and reaching institution, the university is committed to intellectual leadership, and to excellence in both developing knowledge and conveying that knowledge to its students. The University of Karachi meets the commitments to preserve knowledge through its instructional and research programs for higher level education. Wikipedia.

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Nadeem A.,University of Karachi | Howarth M.P.,University of Surrey
IEEE Communications Surveys and Tutorials | Year: 2013

In the last decade, mobile ad hoc networks (MANETs) have emerged as a major next generation wireless networking technology. However, MANETs are vulnerable to various attacks at all layers, including in particular the network layer, because the design of most MANET routing protocols assumes that there is no malicious intruder node in the network. In this paper, we present a survey of the main types of attack at the network layer, and we then review intrusion detection and protection mechanisms that have been proposed in the literature. We classify these mechanisms as either point detection algorithms that deal with a single type of attack, or as intrusion detection systems (IDSs) that can deal with a range of attacks. A comparison of the proposed protection mechanisms is also included in this paper. Finally, we identify areas where further research could focus. © 1998-2012 IEEE.

Khan A.,University of Karachi
World journal of gastroenterology : WJG | Year: 2012

To determine antibiotic resistance of Helicobacter pylori (H. pylori) in Pakistan and its correlation with host and pathogen associated factors. A total of 178 strains of H. pylori were isolated from gastric biopsies of dyspeptic patients. Susceptibility patterns against first and second-line antibiotics were determined and trends of resistance were analyzed in relation to the sampling period, gastric conditions and cagA gene carriage. The effect of cagA gene on the acquisition of resistance was investigated by mutant selection assay. The observations showed that monoresistant strains were prevalent with rates of 89% for metronidazole, 36% for clarithromycin, 37% for amoxicillin, 18.5% for ofloxacin and 12% for tetracycline. Furthermore, clarithromycin resistance was on the rise from 2005 to 2008 (32% vs 38%, P = 0.004) and it is significantly observed in non ulcerative dyspeptic patients compared to gastritis, gastric ulcer and duodenal ulcer cases (53% vs 20%, 18% and 19%, P = 0.000). On the contrary, metronidazole and ofloxacin resistance were more common in gastritis and gastric ulcer cases. Distribution analysis and frequencies of resistant mutants in vitro correlated with the absence of cagA gene with metronidazole and ofloxacin resistance. The study confirms the alarming levels of antibiotic resistance associated with the degree of gastric inflammation and cagA gene carriage in H. pylori strains.

Haider S.,University of Karachi
Neurochemical research | Year: 2012

Memory impairment is a major problem afflicting mankind. The association between memory functions and neurotransmitter functions is of great interest for understanding brain function. Serotonergic pathways play an important role in the modulation of memory functions but the importance of its receptor types and subtypes on memory functions is still unclear. Activation and blockade of various serotonin (5-HT) receptors has been reported to alter cognitive processes and 5-HT receptor antagonism could be beneficial in the treatment of cognitive diseases. The role of 5-HT on memory functions is complicated. Among the 5-HT receptors subtypes, 5-HT(1A) receptors are of special interest because these receptors are present in the brain areas involved in learning and memory functions such as hippocampus and cortex. The present study was therefore designed to investigate the effect of activation and blockade of somatodendritic and/or postsynaptic 5-HT(1A) receptor on learning and memory functions in rats using modified version of water maze. In this study, 8-OH-DPAT (8-hydroxy-2-(di-N-propylamino) tetralin) at 0.3 mg/kg significantly enhanced learning acquisition (LA), short-term memory (STM) and long term memory (LTM) of rats pre-injected with saline suggesting that the activation of pre-synaptic 5-HT(1A) receptors by its agonist enhanced the memory functions of rats. Conversely, rats injected with 8-OH-DPAT at 1.0 mg/kg exhibited impaired LA and STM and had no effect on LTM. It was also shown in this study that blockade of 5-HT(1A) receptors by spiperone enhanced LA, had no effect on STM but impaired the LTM, which showed that the blockade of 5-HT(1A) receptors by its antagonist exerts different effect on different types of memory. This study suggests that 5-HT(1A) receptor could be used as a significant pharmacological target for the treatment of CNS diseases. Unraveling the role of serotonin in cognition and memory disorders could provide better therapy and it may lead to new insights in our understandings of learning and memory.

Karim Z.,University of Karachi
Bulletin of Environmental Contamination and Toxicology | Year: 2011

Health risk caused by the exposure to trace metals in water through different exposure pathways was investigated. Graphite furnace atomic absorption spectrometry was used for the determination of trace metals (nickel, copper, chromium, lead, cobalt, manganese and iron) in drinking water samples. The concentration of metals was compared with the world health organization (WHO) drinking water quality guideline values. Risk of metals on human health was evaluated using Hazard Quotient (HQ). Hazard quotients of all metals through oral ingestion and dermal absorption are found in the range of 1.11 × 10 -2 to 1.35 × 10 -1 and 8.52 × 10 -5 to 9.75 × 10 -2, respectively. The results of the present study reflect the unlikely potential for adverse health effects to the inhabitants of Karachi due to the oral ingestion and dermal absorption of water containing these metals. © 2011 Springer Science+Business Media, LLC.

Stress is the major predisposing and precipitating factor in the onset of depression which is the most significant mental health risk for women. Behavioral studies in animal models show that female sex though less affected by an acute stressor; exposure to repeated stressors induces coping deficits to impair adaptation in them. A decrease in the function of 5-hydroxytryptamine (5-HT; serotonin) in the hippocampus and an increased function of the 5-HT-1A receptor in the raphe nucleus coexist in depression. Pharmacological and neurochemical data are relevant that facilitation of serotonin neurotransmission via hippocampus due to desensitization of somatodendritic 5-HT1A receptors may lead to adaptation to stress. The present article reviews research on sex related differences of raphe-hippocampal serotonin neurotransmission to find a possible answer that may account for the sex differences of adaptation to stress reported in preclinical research and greater incidence of depression in women than men. © 2011 Bentham Science Publishers.

Haleem D.J.,University of Karachi
Behavioural Pharmacology | Year: 2012

Patients with anorexia nervosa (AN) show extreme dieting weight loss, hyperactivity, depression/anxiety, self-control, and behavioral impulsivity. 5-Hydroxytryptamine (5-HT; serotonin) is involved in almost all the behavioral changes observed in AN patients. Both genetic and environmental factors contribute toward the pathogenesis of AN. It is a frequent disorder among adolescent girls and young women and starts as an attempt to lose weight to look beautiful and attractive. Failure to see the turning point when fasting becomes unreasonable leads to malnutrition and AN. Tryptophan, the precursor of serotonin and an essential amino acid, is only available in the diet. It is therefore likely that excessive diet restriction and malnutrition decrease brain serotonin stores because the precursor is less available to the rate-limiting enzyme of 5-HT biosynthesis, which normally exists unsaturated with its substrate. Evidence shows that diet restriction-induced exaggerated feedback control over 5-HT synthesis and the smaller availability of tryptophan decreases serotonin neurotransmission at postsynaptic sites, leading to hyperactivity, depression, and behavioral impulsivity. A compensatory upregulation of postsynaptic 5-HT-1A receptors and hypophagic serotonin receptors may be involved in anxiety and suppression of appetite. It is suggested that tryptophan supplementation may improve pharmacotherapy in AN. © Lippincott Williams & Wilkins.

The work presented here describes the fabrication of a novel drug delivery system, which consists of gold nanorods and doxorubicin, with the attachment of thioctic acid and folic acid, for the targeted release of drug to cancer cells. Doxorubicin, the potent anticancer drug, is widely used to treat various cancers. Gold nanorods were functionalized chemically to generate active groups for the attachment of drug molecules and subsequently attached to folic acid. The resulting nanostructure was characterized by UV-visible-NIR spectrophotometry, TEM techniques, zeta potential measurement and subsequently used to target folate receptorexpressing cancers cells for the delivery of doxorubicin. We generated a release profile for the release of doxorubicin from the nanostructures in KB cells using single-molecule fluorescence intensity images and fluorescence lifetime images. The results indicated that the nanorods were able to enter the target cells because of the attachment of folic acid and used as a carriers for the targeted delivery of doxorubicin. © 2014 Informa UK Ltd.

Azmat R.,University of Karachi
Current Pharmaceutical Biotechnology | Year: 2013

The effect of mixed inoculums of VAM (Vesicular Arbuscular Mycorrhizas) fungi on seed growth and photosynthetic apparatus in green house was monitored. The plants were watered daily with tap water. Plants were cultivated in natural environment in mid of March (2011). A direct relation between root length and water contents suggests a defense mechanism of MP (microrihzal plants) against the fungal stress. It was also supported by the fact that the leaf area of MP was much greater as compared to the NMP (non microrihzal plants) with elevated concentration of all chlorophyllus pigments in 30 days. An increase in the surface area of the leaf and concentration of the pigments, may be for an acceleration in absorption of CO2 for reduction of it into glucose through oxidation of water molecule. The non-significant decline in glucose contents support the above hypothesis of rapid redox reaction mechanism which was established to overcome the stress. The positive effects of mycorrhizal which were already mentioned in the literature were reported in this article in relations of survival strategies of the plant, adapted in stress conditions. An increase in the chlorophyll contents (30 d) and leaf area of plants possibly attributed with absorption of solar radiation for the protection of plants. It was also supported by the higher concentration of carotenoids (30 d) that may have an additional function of regulation of certain developmental responses and screening of light to save the plants from stress conditions. © 2013 Bentham Science Publishers.

Class II major histocompatibility complex (MHC II) molecules as expressed by antigen-presenting cells are heterodimeric cell-surface glycoprotein receptors that are fundamental in initiating and propagating an immune response by presenting tumor-associated antigenic peptides to CD4+/T H cells. The loading efficiency of such peptides can be improved by small organic compounds (MHC Loading Enhancers-MLEs), that convert the non-receptive peptide conformation of MHC II to a peptide-receptive conformation. In a reversible reaction, these compounds open up the binding site of MHC II molecules by specific interactions with a yet undefined pocket. Here, we performed molecular docking and molecular dynamics simulation studies of adamantyl compounds on the predicted cavity around the P1 pocket of 2 allelic variants of HLA-DRs. The purpose was to investigate the suitability of adamantyl compounds as MLEs at the dimorphic β86 position. Docking studies revealed that besides numerous molecular interactions formed by the adamantyl compounds, Asnβ82, Tyrβ83, and Thrβ90 are the crucial amino acid residues that are characterized as the "sensors" of peptide loading. Molecular dynamics simulation studies exposed the dynamical structural changes that HLA-DRs adopted as a response to binding of 3-(1-adamantyl)-5-hydrazidocarbonyl- 1H-pyrazole (AdCaPy). The conformations of AdCaPy complexed with the Glyβ86 HLA-DR allelic variant are well correlated with the stabilized form of peptide-loaded HLA-DRs, further confirming the role of AdCaPy as a MLE. Hydrogen bonding interaction analysis clearly demonstrated that after making suitable contacts with AdCaPy, HLA-DR changes its local conformation. However, AdCaPy complexed with HLA-DR having Valβ86 at the dimorphic position did not accommodate AdCaPy as MLE due to steric hindrance caused by the valine. © 2010 Springer Science+Business Media B.V.

Dysfunctions of the basal ganglia are associated with a number of neurological and psychiatric conditions including Parkinson's disease and schizophrenia. Current treatments of these disorders are mostly symptomatic and inadequate, and are often associated with a number of unwanted side-effects. The striatum, the terminal region of the nigrostriatal dopamine pathway, is the main input nucleus of the basal ganglia, and dopamine neurotransmission through the nigrostriatal pathway plays a crucial role in the modulation of basal ganglia output and mediated behaviors. Evidence suggests a role of 5-hydroxytryptamine (5-HT; serotonin)-1A receptors in the modulation of dopamine neurotransmission and in improving pharmacotherapy in schizophrenia and Parkinson's disease. This review concerns the role of 5-HT1A receptors in the modulation of nigrostriatal dopamine neurotransmission, with the aim of providing guidelines for future research to improve pharmacotherapy. The current state of knowledge suggests that drugs simultaneously targeting dopamine D2 and 5-HT1A receptors may improve pharmacotherapy for schizophrenia and Parkinson's disease. Activation of somatodendritic 5-HT1A receptors in the dorsal raphe nucleus has an important role in the alleviation of extrapyramidal symptoms and levodopa-induced dyskinesia induced by antipsychotic treatment. Drugs acting exclusively through dopamine D2 and 5-HT1A receptors are highly needed to validate the potential role of 5-HT1A receptors in improving therapeutics for Parkinson's disease and schizophrenia. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

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