Search tips
Search criteria

Results 1-16 (16)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
1.  Epigenetic mechanisms in cancer: push and pull between kneaded erasers and fate writers 
Research concerning the epigenome over the years has systematically and sequentially shown substantial development and we have moved from global inhibition of modifications of the epigenome toward identification and targeted therapy against tumor-specific epigenetic mechanisms. In accordance with this approach, several drugs with epigenetically modulating activity have received considerable attention and appreciation, and recently emerging scientific evidence is uncovering details of their mode of action. High-throughput technologies have considerably improved our existing understanding of tumor suppressors, oncogenes, and signaling pathways that are key drivers of cancer. In this review, we summarize the general epigenetic mechanisms in cancer, including: the post-translational modification of DNA methyltransferase and its mediated inactivation of Ras association domain family 1 isoform A, Sonic hedgehog signaling, Wnt signaling, Notch signaling, transforming growth factor signaling, and natural products with epigenetic modification ability. Moreover, we introduce the importance of nanomedicine for delivery of natural products with modulating ability to epigenetic machinery in cancer cells. Such in-depth and comprehensive knowledge regarding epigenetic dysregulation will be helpful in the upcoming era of molecular genomic pathology for both detection and treatment of cancer. Epigenetic information will also be helpful when nanotherapy is used for epigenetic modification.
PMCID: PMC4425311  PMID: 25995628
epigenetic; modification; methylation; natural products; cancer
2.  Recent progress in fungus-derived bioactive agents for targeting of signaling machinery in cancer cells 
It is becoming increasingly understood that tumor cells may have different mutations and dependencies on diverse intracellular signaling cascades for survival or metastatic potential. Overexpression of oncogenes, inactivation of tumor suppressor genes, genetic/epigenetic mutations, genomic instability, and loss of apoptotic cell death are some of the mechanisms that have been widely investigated in molecular oncology. We partition this multicomponent review into the most recent evidence on the anticancer activity of fungal substances obtained from in vitro and xenografted models, and these fungal substances modulate expression of oncogenic and tumor suppressor miRNAs. There are some outstanding questions regarding fungus-derived chemical-induced modulation of intracellular signaling networks in different cancer cell lines and preclinical models. Certain hints have emerged, emphasizing mechanisms via which apoptosis can be restored in TRAIL-resistant cancer cells. Reconceptualization of the knowledge obtained from these emerging areas of research will enable us to potentially identify natural agents with notable anticancer activity and minimal off-target effects. Integration of experimentally verified evidence obtained from cancer cell line gene expression with large-scale functional screening results and pharmacological sensitivity data will be helpful in identification of therapeutics with substantial efficacy. New tools and technologies will further deepen our understanding of the signaling networks that underlie the development of cancer, metastasis, and resistance to different therapeutics at both a personal and systems-wide level.
PMCID: PMC4381899  PMID: 25848216
fungal products; cell signaling; cancer; apoptosis; miRNA; xenograft
3.  Severe Plasmodium falciparum infection mimicking acute myocardial infarction 
Malaria Journal  2014;13:341.
This case report describes a case of presumed acute myocardial infarction in a returned traveler who was later diagnosed to have severe malaria. Emergency coronary angiography was normal and subsequent peripheral blood film was positive for Plasmodium falciparum.
PMCID: PMC4161891  PMID: 25176417
Myocardial infarction; Severe Plasmodium falciparum; Malaria; Coronary angiography
4.  Association of the use of bacterial cell wall synthesis Inhibitor drugs in early childhood with the Developmental Defects of Enamel 
Objective: Our objective of the study was to determine the association between frequent use of Penicillins and Cephalosporins with developmental defects of enamel in pediatric age group.
Methods: This is a cross sectional study, conducted at Ziauddin University. A total of 367 children, having the history of either Penicillin or Cephalosporin exposure were included. The parents of children were asked to complete a questionnaire related to disease and drug history. Dental examination was carried out to assess the hypomineralization in tooth enamel based on modified Developmental Defects of Enamel (DDE) index.
Results: Out of 367 children, 124 (34%) were males and females were 243(66%). In the study group 22.6% (n= 83) of children were found to be hypomineralized. The maximum type of teeth defects were diffused opacities that was 12.0% (n=44). The statistically significant association (p-value < 0.05) was found between frequency of antibiotic use and hypomineralization for most teeth. Children who were exposed to either Penicillins or Cephalosporin in early childhood showed significant (p-value < 0.002) hypomineralized enamel.
Conclusion: This study concludes that frequent use of antibiotics such as penicillins and cephalosporins has positive association with enamel hypomineralization in developing tooth structure.
PMCID: PMC3999017  PMID: 24772150
Molar Incisor Hypomineralization (MIH); Developmental Defects of Enamel (DDE); Hypominerelization
5.  Forming-free bipolar resistive switching in nonstoichiometric ceria films 
The mechanism of forming-free bipolar resistive switching in a Zr/CeO x /Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrO y layer at the Zr/CeO x interface. X-ray diffraction studies of CeO x films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeO x film and in the nonstoichiometric ZrO y interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).
PMCID: PMC3927661  PMID: 24467984
Resistive switching; Space charge-limited conduction (SCLC); Metal-insulator-metal structure; Cerium oxide; Oxygen vacancy
6.  Sn doping induced enhancement in the activity of ZnO nanostructures against antibiotic resistant S. aureus bacteria 
Highly ionic metal oxide nanostructures are attractive, not only for their physiochemical properties but also for antibacterial activity. Zinc oxide (ZnO) nanostructures are known to have inhibitory activity against many pathogens but very little is known about doping effects on it. The antibacterial activity of undoped ZnO and tin (Sn) doped ZnO nanostructures synthesized by a simple, versatile, and wet chemical technique have been investigated against Escherichia coli, methicillin-resistant Staphylococcus aureus, and Pseudomonas aeruginosa bacterial strains. It has been interestingly observed that Sn doping enhanced the inhibitory activity of ZnO against S. aureus more efficiently than the other two bacterial strains. From cytotoxicity and reactive oxygen species (ROS) production studies it is found that Sn doping concentration in ZnO does not alter the cytotoxicity and ROS production very much. It has also been observed that undoped and Sn doped ZnO nanostructures are biosafe and biocompatible materials towards SH-SY5Y Cells. The observed behavior of ZnO nanostructures with Sn doping is a new way to prevent bacterial infections of S. aureus, especially on skin, when using these nanostructures in creams or lotions in addition to their sunscreen property as an ultraviolet filter. Structural investigations have confirmed the formation of a single phase wurtzite structure of ZnO. The morphology of ZnO nanostructures is found to vary from spherical to rod shaped as a function of Sn doping. The excitation absorption peak of ZnO is observed to have a blue shift, with Sn doping leading toward a significant tuning in band gap.
PMCID: PMC3792850  PMID: 24109181
nanostructures; Sn doped ZnO; S. aureus; antibacterial activity
7.  Is It Possible to Improve Memory Function by Upregulation of the Cholesterol 24S-Hydroxylase (CYP46A1) in the Brain? 
PLoS ONE  2013;8(7):e68534.
We previously described a heterozygous mouse model overexpressing human HA-tagged 24S-hydroxylase (CYP46A1) utilizing a ubiquitous expression vector. In this study, we generated homozygotes of these mice with circulating levels of 24OH 30–60% higher than the heterozygotes. Female homozygous CYP46A1 transgenic mice, aged 15 months, showed an improvement in spatial memory in the Morris water maze test as compared to the wild type mice. The levels of N-Methyl-D-Aspartate receptor 1, phosphorylated-N-Methyl-D-Aspartate receptor 2A, postsynaptic density 95, synapsin-1 and synapthophysin were significantly increased in the hippocampus of the CYP46A1 transgenic mice as compared to the controls. The levels of lanosterol in the brain of the CYP46A1 transgenic mice were significantly increased, consistent with a higher synthesis of cholesterol. Our results are discussed in relation to the hypothesis that the flux in the mevalonate pathway in the brain is of importance in cognitive functions.
PMCID: PMC3712995  PMID: 23874659
8.  Validation of PCR Assay for Identification of Sarcoptes scabiei var. hominis  
Iranian Journal of Parasitology  2013;8(3):437-440.
Infestation of the skin by the “itch mite” Sarcoptes scabiei var. hominis results in a contagious skin infection in humans called “scabies”. By resolving morphology issues, the present study was designed to be acquainted with itch mite by molecular markers.
The mite samples were collected from scabies patients by visiting government hospitals of twin City, Pakistan. For successful molecular detection approach, preparation of Sarcoptes mite DNA by commercial DNA extraction kit method. Furthermore, two primers i.e. Sarms 15 F/R and 16S D1/D2 were used to amplify target sequence by using PCR. The amplified products were then separated by agarose gel, electrophoresis and analyzed after staining and visualizing in UV transilluminator.
Analysis of PCR product showed one specific band of 178 bp with primer Sarms 15 F/R, while, with primer 16S D1/D2 bands of 460 bp and 600 bp were observed on 2% agarose gel. The appearance of different band of 600 bp revealed that it might be due to heteroplasmy state present in the Pakistani Sarcoptes mites population.
Current study adds validity to the claim that PCR is more accurate, specific and sensitive in the detection of the ectoparasites even in smallest amount.
PMCID: PMC3887246  PMID: 24454438
Sarcoptes scabiei; PCR technique; DNA extraction; Itch mite DNA
9.  Antibacterial, Antifungal, Cytotoxic, Phytotoxic, Insecticidal, and Enzyme Inhibitory Activities of Geranium wallichianum 
The present study describes the phytochemical investigations of the crude extracts of rhizomes and leaves of Geranium wallichianum. The crude extracts were fractionated to obtain n-hexane, ethyl acetate, and n-butanol fractions, which were subjected to different biological activities and enzyme inhibition assays to explore the therapeutic potential of this medicinally important herb. The results indicated that the crude extracts and different fractions of rhizomes and leaves showed varied degree of antimicrobial activities and enzyme inhibitions in different assays. Overall, the rhizome extract and its different fractions showed comparatively better activities in various assays. Furthermore, the purified constituents from the repeated chromatographic separations were also subjected to enzyme inhibition studies against three different enzymes. The results of these studies showed that lipoxygenase enzyme was significantly inhibited as compared to urease. In case of chemical constituents, the sterols (2–4) showed no inhibition, while ursolic acid (1) and benzoic ester (6) showed significant inhibition of urease enzymes.
PMCID: PMC3461298  PMID: 23049606
10.  Group 10 allergens (tropomyosins) from house-dust mites may cause covariation of sensitization to allergens from other invertebrates 
Allergy & Rhinology  2012;3(2):e74-e90.
Group 10 allergens (tropomyosins) have been assumed to be a major cause of cross-reactivity between house-dust mites (HDMs) and other invertebrates. Despite all of the published data regarding the epidemiology, percent IgE binding and level of sensitization in the population, the role of tropomyosin as a cross-reactive allergen in patients with multiple allergy syndrome still remains to be elucidated. Homology between amino acid sequences reported in allergen databases of selected invertebrate tropomyosins was determined with Der f 10 as the reference allergen. The 66.9 and 54.4% identities were found with selected crustacean and insect species, respectively, whereas only 20.4% identity was seen with mollusks. A similar analysis was performed using reported B-cell IgE-binding epitopes from Met e1 (shrimp allergen) and Bla g7 (cockroach allergen) with other invertebrate tropomyosins. The percent identity in linear sequences was higher than 35% in mites, crustaceans, and cockroaches. The polar and hydrophobic regions in these groups were highly conserved. These findings suggest that tropomyosin may be a major cause of covariation of sensitization between HDMs, crustaceans, and some species of insects and mollusks.
PMCID: PMC3548612  PMID: 23342293
Cross-reactivity of tropomyosins; group 10 allergens; HDM allergens; homology; IgE-binding epitopes; multiple allergy syndrome; tropomyosins
11.  World Allergy Organization Study on Aerobiology for Creating First Pollen and Mold Calendar With Clinical Significance in Islamabad, Pakistan; A Project of World Allergy Organization and Pakistan Allergy, Asthma & Clinical Immunology Centre of Islamabad 
Pollen and mold allergies are highly problematic in Islamabad. This study was conducted to investigate the type and concentration of airborne pollens/molds causing allergic diseases in susceptible individuals. A volumetric spore trap (Burkard) was placed at the height of 11 m and ran continuously for 3 years. Once a week, the collecting drum was prepared by affixing Melinex tape with a double sided adhesive that was coated with a thin layer of silicone grease. Every Sunday at 9:00 AM the drum was replaced by another drum and the pollen/mold spores were removed and permanently mounted on slides. Using a microscope, the trapped particles were identified and recorded as counts per cubic meter of air per hour. From these data, the pollen and mold calendars were constructed and expressed as counts per cubic meter of air per day. Skin prick tests were performed on more than 1000 patients attending the Pakistan Allergy, Asthma & Clinical Immunology Centre of Islamabad. The results indicated that there were 2 main pollen plants that contributed to seasonal allergies. These were Broussonetia papyrifera and Cannabis sativa during the March/April season and the July/September season, respectively. Although mold spores were continuously detected throughout the year, the most prominent mold was undetected mold and unconfirmed mold species similar to Stachybotrys species, which was high from July to September/October. Two additional molds contributing to allergic reactions were Pithomyces species and Cladosporium species, which were active during January and April, with the latter also being detected between October and November. These results may prove beneficial to both patients and physicians in planning a therapeutic protocol for avoidance and amelioration.
PMCID: PMC3651178  PMID: 23283209
pollen and mold calendar; aerobiology; Islamabad; Burkard spore trap; Broussonetia papyrifera; Cannabis sativa; skin prick test; SPT; asthma; allergic rhinitis
12.  Oculodentodigital Syndrome with Syndactyly Type III in a Pakistani consanguineous family 
Oculodentodigital syndrome (ODD; OMIM #164200) is a rare autosomal dominant disorder with pleiotropic effects. It is caused by mutation in gap junction protein α 1 (GJA1) gene which encodes connexion 43. ODD is characterised by symptoms i.e. craniofacial, neurologic, limb, ocular abnormalities, syndactyly type III of the hands, phalangeal abnormalities, diffuse skeletal dysplasia, enamel dysplasia, and hypotrichosis.
To study the Molecular Genetics of Oculodentodigital syndrome.
Patients/materials and methods
Our current study includes a Pakistani family affected with ODD. Clinical evaluation revealed that this family shows typical form of ODD with Syndactyly type III. Mutations in GJA1 have been reported in ODD and also in syndactyly type III. In this study we sequenced the coding exons of GJA1 gene in affected and normal individuals of the family for mutation detection.
Direct sequencing of the affected individuals showed a mutation at the nucleotide position 389 T>C. This mutation changed the codon 130 from Isoleucine to Threonine. Normal family members did not show this mutation.
Our study showed no gross neurological upset with I130T mutation in GJA1 gene. This may present novel phenotypic outcome with the I130T. The study will help in better understanding of pathophysiology of oculodentodigital syndrome and type III syndactyly.
PMCID: PMC3399675  PMID: 22826718
diffuse skeletal dysplasia; GJA1 gene; Oculodentodigital Syndrome; Syndactyly Type III
13.  TRAIL and vitamins: opting for keys to castle of cancer proteome instead of open sesame 
Cancer is a multifaceted molecular disorder that is modulated by a combination of genetic, metabolic and signal transduction aberrations, which severely impair the normal homeostasis of cell growth and death. Accumulating findings highlight the fact that different genetic alterations, such as mutations in tumor suppressor genes, might be related to distinct and differential sensitivity to targeted therapies. It is becoming increasingly apparent that a multipronged approach that addresses genetic milieu (alterations in upstream and/or parallel pathways) eventually determines the response of individual tumors to therapy. Cancerous cells often acquire the ability to evade death by attenuating cell death pathways that normally function to eliminate damaged and harmful cells. Therefore impaired cell death nanomachinery and withdrawal of death receptors from cell surface are some of major determinants for the development of chemotherapeutic resistance encountered during treatment. It is therefore essential to emphasize underlying factors which predispose cells to refractoriness against TRAIL mediated cell death pathway and the relevant regulatory components involved. We bring to limelight the strategies to re-sensitize TRAIL resistant cells via vitamins to induce apoptosis.
PMCID: PMC3502079  PMID: 22672528
15.  Homozygous frame shift mutation in ECM1 gene in two siblings with lipoid proteinosis 
The extracellular matrix protein 1 (ECM1) is a glycoprotein, expressed in skin and other tissues. Loss-of-function mutation in ECM1 causes a rare autosomal recessive disorder called lipoid proteinosis. Lipoid proteinosis is presented by varying degrees of skin scars, beaded papules along the eyelid margins, variable signs of hoarseness of voice and respiratory disorders. More than 250 cases of this disorder have been described in the literature, but occurrence of lipoid proteinosis in siblings is very rare. This study was designed to investigate the possible mutation causing lipoid proteinosis in a Pakistani family and to elaborate the scope of possible genetic changes, causing the genodermatosis in Pakistan.
Main observations
In this study, two siblings (12 and 9-years sisters) were presented with scaly itchy lesions on whole body, hoarse voice and macroglossia. Their deceased father had similar clinical manifestations but mother and younger brother were unaffected. Blood samples from clinically affected and unaffected family members were collected with informed consent. The coding region of ECM1 gene containing 10 exons were amplified and sequenced.
Both the affected siblings were shown to have homozygous frame shift mutation by deletion of the nucleotide T at 507, codon 169, exon 6. This resulted in a frame shift from codon 169 and appearance of a premature stop codon at 177, causing formation of a mutated protein (176 amino acids) instead of normal ECM1 protein (540 amino acids).
A case of homozygous 62-bp insertion in ECM1 gene causing lipoid proteinosis has been reported in another Pakistani family. The current study presents a homozygous frame shift mutation supporting an unusual function of ECM1 protein and broadens the spectrum of disease-linked mutations in this rare case of genodermatosis in this region.
PMCID: PMC3157823  PMID: 21886756
extracellular matrix protein 1; ECM1; gene; genodermatosis; lipoid proteinosis; mutation

Results 1-16 (16)