Publications by authors named "Talat Mahmood"

16 Publications

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Custom-designed Small Animal focal iRradiation Jig (SARJ): design, manufacture and dosimetric evaluation.

BJR Open 2020 6;2(1):20190045. Epub 2020 Mar 6.

Medical Physics and Radiation Engineering, Canberra Health Services, Canberra, ACT, Australia.

Objective: Preclinical animal models allow testing and refinement of novel therapeutic strategies. The most common preclinical animal irradiators are fixed source cabinet irradiators, which are vastly inferior to clinical linear accelerators capable of delivering highly conformal and precise treatments. The purpose of this study was to design, manufacture and test an irradiation jig (mall nimal focal iradiation ig, SARJ) that would enable focal irradiation of subcutaneous tumours in a standard fixed source cabinet irradiator.

Methods And Materials: A lead shielded SARJ was designed to rotate animal holders about the longitudinal axis and slide vertically from the base plate. Radiation dosimetry was undertaken using the built-in ion chamber and GAFChromic RTQA2 and EBT-XD films. Treatment effectiveness was determined by irradiating mice with subcutaneous melanoma lesions using a dose of 36 Gy in three fractions (12 Gy x 3) over three consecutive days.

Results: The SARJ was tested for X-ray shielding effectiveness, verification of dose rate, total dose delivered to tumour and dose uniformity. Accurate and uniform delivery of X-ray dose was achieved. X-ray doses were limited to the tumour site when animal holders were rotated around their longitudinal axis to 15 and 195, allowing sequential dose delivery using parallel-opposed tangential beams. Irradiation of subcutaneous melanoma tumour established on the flanks of mice showed regression.

Conclusion: SARJ enabled delivery of tangential parallel-opposed radiation beams to subcutaneous tumours in up to five mice simultaneously. SARJ allowed high throughput testing of clinically relevant dose delivery using a standard cabinet-style fixed source irradiator.

Advances In Knowledge: A custom designed jig has been manufactured to fit into conventional cabinet irradiators and is dosimetrically validated to deliver clinically relevant dose distributions to subcutaneous tumours in mice for preclinical studies.
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http://dx.doi.org/10.1259/bjro.20190045DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594899PMC
March 2020

Surfing Behind a Boat: Quality and Reliability of Online Resources on Scaphoid Fractures.

J Hand Surg Asian Pac Vol 2016 10;21(3):374-81

* Department of Trauma & Orthopedic Surgery, Mayo General Hospital, Castlebar, Co. Mayo, Ireland.

Background: Patients seeking information and advice on treatment of scaphoid fractures unknowingly confront longstanding medical controversies surrounding the management of this condition. However, there are no studies specifically looking into the quality and reliability of online information on scaphoid fractures.

Methods: We identified 44 unique websites for evaluation using the term "scaphoid fractures". The websites were categorized by type and assessed using the DISCERN score, the Journal of the American Medical Association (JAMA) benchmark criteria and the Health on the net (HON) code.

Results: The majority of websites were commercial (n = 13) followed by academic (n = 12). Only seven of the websites were HON certified. The mean DISCERN score was 43.8. Only 4 websites scored 63 or above representing excellent quality with minimal shortcomings but 13 websites scored 38 or below representing poor or very poor quality. The mean JAMA benchmark criteria score was 2.2. The Governmental and Non-Profit Organizations category websites had the highest mean JAMA benchmark score. The websites that displayed the HON-code seal had higher mean DISCERN scores and higher mean JAMA benchmark scores compared to websites that did not display the seal.

Conclusions: Good quality health information is certainly available on the Internet. However, it is not possible to predict with certainty which sites are of higher quality. We suggest clinicians should have a responsibility to educate their patients regarding the unregulated nature of medical information on the internet and proactively provide patients with educational resources and thus help them make smart and informed decisions.
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http://dx.doi.org/10.1142/S2424835516500375DOI Listing
October 2016

Anti-proliferative and computational studies of two new pregnane glycosides from Desmidorchis flava.

Bioorg Chem 2016 08 31;67:95-104. Epub 2016 May 31.

UoN Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, P.O. Box 33, Postal Code 616, Birkat Al Mauz, Nizwa, Oman. Electronic address:

Two new pregnane glycosides named desmiflavasides C (1) and D (2) were isolated from the sap of Desmidorchis flava (N.E.Br.) Meve & Liede and have had their structures confirmed from 1D and 2D NMR spectroscopic techniques and mass spectrometry (ESIMS). Further, the effects of desmiflavasides C (1) and D (2) on the proliferation of breast and ovarian cancer cells as well as normal breast epithelial cells in culture were examined. Interestingly, desmiflavasides C (1) and D (2) were able to cause a substantial decline in the viability of cancer cells in a concentration-dependent manner. Moreover, treatment of normal cells with compound 2 resulted in no significant growth inhibition, indicating that its cytotoxicity was selective towards cancer cells. Furthermore, the activity of compound 2 against cancer as well as normal epithelial cells was found to be similar to that of a previously reported pregnane glycoside, nizwaside (3). Molecular docking studies of desmiflavasides C (1) and D (2) and nizwaside (3) were carried out to ascertain if it was possible to predict any important binding orientations required of small molecule drug candidates with suggested protein target molecules for the purposes of being able to predict the affinity and activity to an acceptable degree by such compounds. Desmiflavaside D (2) showed a relatively good binding affinity (-22.4449kcal/mol) as compared to the other two compounds viz., nizwaside (3) (-20.0319kcal/mol), and desmiflavaside C (1) (-19.4042kcal/mol). Docking results of the three pregnane glycosides viz., 1-3 revealed that these ligand molecules can accurately interact with the target protein.
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http://dx.doi.org/10.1016/j.bioorg.2016.05.008DOI Listing
August 2016

Storage Stability of Kinnow Fruit (Citrus reticulata) as Affected by CMC and Guar Gum-Based Silver Nanoparticle Coatings.

Molecules 2015 Dec 18;20(12):22645-61. Epub 2015 Dec 18.

Section of Food Science and Technology, Department of Agricultural Sciences, University of Haripur, Haripur 22620, KPK, Pakistan.

The influence of carboxy methyl cellulose (CMC) and guargum-based coatings containing silver nanoparticles was studied on the postharvest storage stability of the kinnow mandarin (Citrus reticulata cv. Blanco) for a period of 120 days (85%-90% relative humidity) at 4 °C and 10 °C. Physicochemical and microbiological qualities were monitored after every 15 days of storage. Overall results revealed an increase in total soluble solid (TSS), total sugars, reducing sugars and weight loss but this increase was comparatively less significant in coated fruits stored at 4 °C. Ascorbic acid, total phenolics, and antioxidant activity was significantly enhanced in coated fruits stored at 4 °C. Titratable acidity significantly decreased during storage except for coated kinnow stored at 4 °C. In control samples stored at 10 °C, high intensity of fruit rotting and no chilling injury was observed. Total aerobic psychrotrophic bacteria and yeast and molds were noticed in all treatments during storage but the growth was not significant in coated fruits at 4 °C. Kinnow fruit can be kept in good quality after coating for four months at 4 °C and for 2 months at 10 °C.
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http://dx.doi.org/10.3390/molecules201219870DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6332021PMC
December 2015

Nizwaside: a new anticancer pregnane glycoside from the sap of Desmidorchis flava.

Arch Pharm Res 2015 Dec 3;38(12):2137-42. Epub 2015 Sep 3.

UoN Chair of Oman's Medicinal Plants and Marine Natural Products, University of Nizwa, Birkat Al Mauz, P. O Box 33, 616, Nizwa, Sultanate of Oman.

The sap from the succulent Desmidorchis flava (N.E.Br) Meve and Liede yielded a new pregnane glycoside, named nizwaside whose structure was established using 1D and 2D NMR techniques as well as mass spectrometry (ESIMS). Nizwaside was tested for anticancer, DPPH antioxidant, urease enzyme inhibition, α-glucosidase enzyme inhibition and acetylcholinesterase inhibition activities. Interestingly, nizwaside showed significant anti-proliferative effects on MDA MB231 breast cancer cells with an IC(50) of 23.5 µg/ml. Moreover, nizwaside was more effective than Doxorubicin, a well-known clinical anticancer drug, in suppressing MDA MB231 cell proliferation even at concentrations lower than that of Doxorubicin (75 µg/ml nizwaside vs. 100 µg/ml Doxorubicin). On the other hand, nizwaside showed relatively weak antioxidant activity with 15 % inhibition.
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http://dx.doi.org/10.1007/s12272-015-0653-0DOI Listing
December 2015

Report: complexation of β-sitosterol with tris (dibenzylideneacetone) dipalladium and its anti-microbial activity.

Pak J Pharm Sci 2015 Mar;28(2):631-4

Federal Urdu University of Arts, Sciences and Technology, Gulshan-e-Iqbal Campus, Karachi, Pakistan.

β-sitosterol is a naturally occurring plant sterol (phytosterol) present in many fruits and vegetables. Scientific research has proven that β-sitosterol is helpful in maintaining the proper functioning of our body. Previously we described the complexation of β-sitosterol with trace metals (Mahmood et al., 2013). Trace metals after the formation of complex unable to absorb in the body and hence eliminated out from the body thus reducing metal toxicity (Marsha, 1996). The present article describes the complexation of μ-sitosterol with Palladium (Pd) metal. Palladium is a toxic metal and due to polluted and hazardous environment traces of this metal can be transferred into the body, which is harmful for human health. Our aim is to make Pd-sterol complex so that this toxic metal (Pd) does not absorb in the body and hence excreted out from the body in the complex form. In order to form this complex μ-sitosterol (Ib) is reacted with Tris (dibenzylideneacetone) dipalladium or [Pd(2) (DBA)(3)] (Ia) in 2:1 ratio in an inert atmosphere and dimethylformamid (DMF) added as a solvent. The resulting complex [Pd(2) (DBA)(3).(β-sitosterol) (Ic) was identified by various spectroscopic techniques such as IR, Mass and (1)H-NMR. This new organo metallic complex (Ic) also showed significant antibacterial and antifungal activity. The present work revealed that Pd-sterol complex does not only reduce metal toxicity but also helpful in minimizing bacterial and fungal infections present in the body. Our research also concluded that we must take plenty of fruits and vegetables in our diet so that natural plant sterol such as β-sitosterol can enhance our defense mechanism and maintain other functions of our body.
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March 2015

Optimization and partial characterization of bacteriocin produced by Lactobacillus bulgaricus -TLBFT06 isolated from Dahi.

Pak J Pharm Sci 2015 Mar;28(2):561-7

Department of Agriculture University of Haripur, Pakistan.

Lactobacillus bulgaricus is one of the predominant lactic acid bacteria of dahi, conferring technological and functional attributes. In the present study thirty dahi samples were investigated for bacteriocin producing L. bulgaricus. Fourteen different isolates were obtained and five were scrutinized for antibacterial activities against food born pathogens. Amongst, a strain TLB06FT was found to have a wide array of antibacterial activities against Gram positive and negative bacteria was selected for further characterization. Growth media optimization for this strain revealed maximum bacteriocin production on MRS media supplemented with glucose (2%), sodium chloride (1%), Tween-80 (0.5%) and yeast extract (1 %). In addition, optimization of growth conditions revealed maximum bacteriocin production at pH 5.5 and temperature of 30-37°C. Bacteriocin showed thermo stability at 90°C and remained highly active in the pH range of 3.5-7.5, inactive by protein catalyzing enzymes and showed no change in activity (800AumL(-1)) when treated with organic solvents and surfactants. The obtained bacteriocin was purified to 1600AU mL(-1) by ammonium sulfate precipitation (80%) by using dialyzing tubing. In the same way, a single peak was obtained by RP-HPLC having antibacterial activity of 6400AU mL(-1). Thus, wild strains of L. bulgaricus have great potential for the production new and novel type of bacteriocins.
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March 2015

Liver transplantation at KFSHRC: achievement and challenges.

Ann Saudi Med 2014 Mar-Apr;34(2):103-6

Prof. Mohammed Al Sebayel, Department of Liver and Small Bowel Transplantation and Hepatobiliary Surgery,, King Faisal Specialist Hospital and Research Centre, T: +966114424818, F: +966114424817,

The liver transplantation program at KFSHRC has been active since 2001. More than 450 liver transplants have been performed so far. The program evolved from adult cadaveric transplant to living donor and recently to pediatric and split techniques. The 1-year survival of patients for both pediatric and adult exceeded 90% and the 5-year survival of patients is more than 80%. Associated with this success are challenges that include: organ shortage, quality of organ harvested, inability to meet the growing national need, increased demand of resource to meet the need of the program, and lack of a collaborative national strategy in organ donation and transplantation.
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http://dx.doi.org/10.5144/0256-4947.2014.103DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6074861PMC
November 2015

Some probiotic and antibacterial properties of Lactobacillus acidophilus cultured from dahi a native milk product.

Int J Food Sci Nutr 2014 Aug 1;65(5):582-8. Epub 2014 Apr 1.

Department of Food Technology, Pir Mehr Ali Shah Arid Agriculture University , Rawalpindi , Pakistan.

In this study, different strains of Lactobacillus acidophilus from dahi were analyzed for certain probiotic and antibacterial properties. Initially, these strains were confirmed by the amplification of 16S rRNA regions and then screened for antibacterial activities against food borne pathogens. The phenotypic relationship between apparent antibacterial activity and cell wall proteins were established by cluster analysis. It was observed that those strains, which have prominent bands having size 22-25 kDa possess antibacterial activity. On the basis of wide spectrum of killing pattern, a strain LA06FT was further characterized that showed no change in its behavior when subjected to the antibiotic protected environment and grow well in acid-bile conditions. The bacteriocin produced by this strain has specific antibacterial activity of 5369.13 AU mg(-1). It remained stable at 60-90 °C and pH range of 4.5-6.5 while proteolytic enzymes inactivate the bacteriocin that confirm its proteinic nature having molecular weight of ≤8.5 kDa.
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http://dx.doi.org/10.3109/09637486.2014.880666DOI Listing
August 2014

Selection and characterization of probiotic culture of Streptococcus thermophilus from dahi.

Int J Food Sci Nutr 2013 Jun 6;64(4):494-501. Epub 2012 Dec 6.

Department of Food Technology, Pir Mehr Ali Shah Arid Agriculture University, Rawalpindi, Pakistan.

For the isolation of probiotic cultures of Streptococcus thermophilus from dahi, we collected 120 samples from the southern regions of Punjab, Pakistan. Eleven isolates were obtained, and six were scrutinized for antibacterial activities against food-borne pathogens. The carbohydrate fermentation profile of these six strains was determined by the API50 CHL system. Additionally, these strains were amplified for their 16S rRNA regions to confirm their genotypic relationship. Furthermore, phenotypic characteristics among these strains were established by S-layer protein analysis of their cell walls by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and by plasmid profiling. The outer cell wall layers of these strains have 6-14 different sizes of protein bands of 27, 34, 37, 40, 45 and 60 kDa molecular weight. Similarly, except S02FT, all strains have a single prominent plasmid of 23 kbp, whereas S02FT has an additional plasmid of 9 kbp. On the basis of this unique feature and a wide spectrum of killing patterns against pathogenic bacteria, S. thermophilus S02FT was further characterized. This culture showed an optimum antibacterial activity of 800 AU/ml at pH 5.0-5.5 and a temperature of 30-37°C. It grows well in in vitro acidic conditions and tolerates bile salt up to 2% concentration. It was resistant to nalidixic acid, ciprofloxacin, gentamicin and sulphamethoxazol, but showed intermediate behaviour to vancomycin and erythromycin.
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http://dx.doi.org/10.3109/09637486.2012.749840DOI Listing
June 2013

Comparison of mechanical pretreatment methods for the enhancement of anaerobic digestion of pulp and paper waste activated sludge.

Water Environ Res 2012 Jun;84(6):497-505

FPInnovations, 570 Saint-Jean Boulevard, Pointe-Claire, Quebec, Canada H9R 3J9.

The conventional anaerobic digestion process, requiring long solids retention times (SRTs) to digest solids, is currently viewed as impractical for the pulp and paper industry because of high capital costs associated with the construction of new digesters. Recent developments in sludge solubilization technology could be promising in reducing digester size, which also allows for the potential use of decommissioned tanks, both of which can reduce the capital cost. Three pretreatment technologies for use with anaerobic digestion were tested on laboratory-scale to investigate their feasibility. The SRTs in all three digesters systematically decreased from 20 to 3 days. The reference digester was fed waste activated sludge (WAS) to serve as the control at the same SRTs. The other digesters were fed WAS that had been preconditioned using mechanical shearing, sonication, or high-pressure homogenization technology. Anaerobic digestion with high-pressure homogenization produced as much methane at 3-day mean SRT as that from the reference digester operated at 20-day SRT. Therefore, a new digester can theoretically be 85% smaller than a conventional digester. An added benefit of WAS to methane conversion is the recovery of nutrients nitrogen and phosphorus.
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http://dx.doi.org/10.2175/106143012x13347678384602DOI Listing
June 2012

Implications of aerated stabilization basin dredging on potential effluent toxicity to fish.

Water Environ Res 2010 May;82(5):440-6

FPInnovations-Paprican Division, Pointe-Claire, Quebec, Canada.

Benthal solids accumulated in aerated stabilization basins (ASBs) must be dredged to regain treatment capacity. While dredging restores treatment performance, it has been associated occasionally with the failure to meet regulatory effluent toxicity limits at the time of dredging. A first study of its kind was undertaken to investigate the implications of ASB dredging on potential effluent toxicity to fish. The study showed that benthal solid slurry removed from the quiescent zone of an ASB with a hydraulic dredge was toxic to rainbow trout with a 96-hour median lethal concentration (LC50) of 2.2%. The high ammonia concentration in the sample was the main cause of fish mortality. Hydrogen sulfide and resin and fatty acids also were present in the dredged material at concentrations that could cause fish mortality. These findings have led to best management practices that can be used to mitigate or eliminate fish toxicity issues during dredging operations.
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http://dx.doi.org/10.2175/106143009x12529484815313DOI Listing
May 2010

Insights into the enhancement of the ASB benthal solids digestion rate.

Authors:
Talat Mahmood

Water Res 2008 May 20;42(10-11):2411-20. Epub 2008 Jan 20.

FPInnovations-Paprican, 570 St-Jean Blvd., Pointe-Claire, QC, Canada H9R 3J9.

Aerated stabilization basins (ASB) accumulate benthal solids as they provide biotreatment to wastewaters. The accumulated solids must digest at a rate that matches the rate of settling of fresh solids in order to maintain the water column depth at the design value. In practice, however, the deposited solids digest at rates much slower than the fresh deposition rates, resulting in solids accumulation in the system. Excessive build-up of solids warrants dredging or abandoning the solids-filled cells in favour of opening new ones, often due to prohibitive dredging costs. An investigating study on factors affecting digestion rate was carried out using benthal solids from a pulp and paper ASB. The rate of digestion was not limited by the lack of macronutrients N, P, and S in the system or by toxicity due to ammonia or sulphide. Oxidation-reduction potential and pH were found conducive to anaerobic digestion throughout the 1120-day study. However, the generation of volatile organic acids from liquefaction/fermentation of solid substrate appeared to be a major factor limiting the digestion rate. Based on laboratory data, operating an ASB in the optimal mesophilic temperature range could be a practical way of enhancing the benthal solids digestion rate.
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http://dx.doi.org/10.1016/j.watres.2008.01.013DOI Listing
May 2008

Pretreatment technologies for advancing anaerobic digestion of pulp and paper biotreatment residues.

Water Res 2007 Nov 15;41(19):4273-86. Epub 2007 Jun 15.

FPInnovations-Paprican, 570 boul. St. Jean, Pointe-Claire, QC, Canada H9R 3J9.

While anaerobic digestion is commonly practiced in the municipal sector, it has not gained popularity in the pulp and paper industry mainly because of its long sludge residence time requirement of 20-30 days. The construction of large digesters to provide such extended residence times is capital-intensive and thus the implementation of anaerobic digestion has remained economically prohibitive. A review of the literature suggests that recent developments in sludge preconditioning technologies have substantially reduced the sludge residence time requirement to the order of 7 days. Also, the preconditioned sludges have been reported to hold potential for higher methane recovery with reduced excess sludge production requiring disposal. Such advantages, coupled with escalating fuel prices and the introduction of carbon credits under the Kyoto Accord, have significantly improved the economics of anaerobic digestion. As the cost of sludge management varies from one mill to another, mill-specific economic assessment of anaerobic digestion could identify cost-saving opportunities.
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http://dx.doi.org/10.1016/j.watres.2007.06.017DOI Listing
November 2007

Use of acid preconditioning for enhanced dewatering of wastewater treatment sludges from the pulp and paper industry.

Water Environ Res 2007 Feb;79(2):168-76

Paprican, 570 St. John's Blvd., Pointe-Claire, Quebec, Canada, H9R 3J9.

In municipal and industrial practices, wastewater treatment sludges are generally conditioned with organic polymers before dewatering. The dewatering polymers are expensive and contribute significantly to the overall sludge management cost. This paper discusses a preconditioning strategy that holds great promise for enhancing dewatering properties of wastewater treatment sludges, while reducing the cost. In this approach, the waste activated sludge (WAS) is briefly preconditioned with an acid before flocculating with an organic polymer. Experimental results showed that acid preconditioning significantly enhanced dewatering. Separately acidifying WAS and subsequently combining it with primary sludge produced higher presscake solids than acidifying the combined sludge to the same final pH. Acidification exhibited the added benefit of reducing Escherichia coli counts in sludge, thus improving its biological character. This may provide flexibility in choosing a beneficial use application.
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http://dx.doi.org/10.2175/106143006x111970DOI Listing
February 2007

A review of secondary sludge reduction technologies for the pulp and paper industry.

Water Res 2006 Jun 15;40(11):2093-112. Epub 2006 May 15.

Paprican, 570 St. John's Boulevard, Pointe-Claire, Que., Canada H9R 3J9.

The broader application of the activated sludge process in pulp and paper mills, together with increased production, have amplified sludge management problems. With sludge management costs as high as 60% of the total wastewater treatment plant operating costs, and increasingly stringent environmental regulations, it is economically advantageous for pulp and paper mills to reduce their biosolids production. In order to provide a state-of-the-art review of secondary sludge reduction technologies, we have considered the scenarios of lower sludge production through process modifications, and waste-activated sludge reduction through post-treatment. A critical evaluation of all candidate reduction technologies indicates that sludge reduction through treatment process changes appears more appealing than post-treatment alternatives. The former approach offers a clear advantage over the latter in that the treatment process changes reduce sludge production in the first place, thus decreasing sludge management cost. Although it is technically feasible to eliminate the need for sludge disposal, it is unlikely to be economically feasible at this time.
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http://dx.doi.org/10.1016/j.watres.2006.04.001DOI Listing
June 2006