Biomedical subjects

Nasir Ahmad

Publications and source records attributed to Nasir Ahmad.

6 recordsLinked to original sources

PubMed2006

Determination of gamma-emitting radionuclides in the inter-tidal sediments off Balochistan (Pakistan) Coast, Arabian Sea.

Natural radionuclide contents of 226Ra, 228Ra and (40)K were studied for inter-tidal sediments collected from selected locations off the745 km long Balochistan Coast using HPGe detector based gamma-spectrometry system. The sampling zone extends from the beaches of Sonmiani (near Karachi metropolis) through Jiwani (close to the border of Iran). The natural radioactivity levels detected in various sediment samples range from 14.4 +/- 2.5 to 36.6 +/- 3.8 Bq kg(-1) for 226Ra, 9.8 +/- 1.2 to 35.2 +/- 2.0 Bq kg(-1) for (228)Ra and 144.6 +/- 9.4 to 610.5 +/- 23.9 Bq kg(-1) for (40)K. No artificial radionuclide was detected in any of the marine coastal sediment samples. 137Cs, (60)Co, 106Ru and 144Ce contents in sediment samples were below the limit of detection. The measured radioactivity levels are compared with those reported in the literature for coastal sediments in other parts of the world. The information presented in this paper will serve as the first ever local radioactivity database for the Balochistan/Makran Coastal belt of Pakistan. The presented data will also contribute to the IAEA's, Asia-Pacific Marine Radioactivity Database (ASPAMARD) and the Global Marine Radioactivity Database (GLOMARD).

Gamma Rays↗

PubMed2006

Does steroid exposure adversely affect the outcome of subacute bacterial endocarditis? Report of two cases.

Multivalvular endocarditis of native cardiac valves due to streptococci in patients without any predisposing conditions has not been reported previously. Moreover, the effect of exposure to systemic steroids on the outcome of subacute bacterial endocarditis (SBE) is not well known. We describe 2 patients with SBE involving 3 native cardiac valves, who were initially exposed to systemic steroid therapy under the clinical impression of 'rheumatologic disorders'.

Adult↗

PubMed2005

Gamma-emitting radionuclides in the shallow marine sediments off the Sindh coast, Arabian Sea.

Determination of gamma emitting radionuclides in shallow marine sediments off the Sindh coast has been carried out using a gamma spectrometry technique. The activity concentration measured in various sediment samples off the Sindh coast has been found to vary from 15.93 +/- 5.22 to 30.53 +/- 4.70 Bq kg(-1) for 226Ra, from 11.72 +/- 1.22 to 33.94 +/- 1.86 Bq kg(-1) for 228Ra and from 295.22 +/- 32.83 to 748.47 +/- 28.75 Bq kg(-1) for 40K. The calculated mean values of radium equivalent activity, absorbed dose rate and effective dose are 98 Bq kg(-1), 49 nGy h(-1) and 0.06 mSv y(-1), respectively. No artificial radionuclide was detected in the samples measured from the study area. As no data on radioactivity of the coastal environment of Pakistan are available, the data presented here will serve as baseline information on radionuclide concentration in shallow sea sediments off the Sindh coast. The data will also be useful for tracking pollution inventories from unusual radiological events (if any) in the territorial waters of the study area. Further, the information presented will contribute to modelling of a regional radioactivity database from the perspectives of the International Atomic Energy Agency's Asia-Pacific Marine Radioactivity Database and Global Marine Radioactivity Database.

Asia↗

PubMed2004

Assessment of iodine levels in the Pakistani diet.

OBJECTIVE: To prevent iodine-related diseases in Pakistan, baseline analytical data for nutritionally and radiologically important elements in typical Pakistani diets were generated. METHODS: Iodine concentrations of representative Pakistani diets were measured by using epithermal and radiochemical neutron activation analyses. RESULTS: The measured iodine values ranged from 26.56 to 239.48 ng/g (dry weight). The geometric mean by geometric standard deviation of the iodine concentration was 67.6 ng/g x 1.8, which equates to a daily iodine intake of 40.0 microg/d x 1.8. CONCLUSIONS: The iodine content of the Pakistani diet is significantly lower than the intakes recommended by the U.S. Food and Nutrition Board (150 microg/d) and the International Commission of Radiological Protection Board (200 microg/d). The iodine intake of the Pakistani population needs to be improved substantially.

Diet↗

PubMed2003

Uranium concentration in typical Pakistani diet.

To strengthen the radiation protection infrastructure in Pakistan, the uranium concentration in daily diet was measured and its associated radiation risks were estimated for the adult population. Food samples were collected from major cities and districts of the country by the market basket method, from which daily diets were prepared. These diet samples were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) at the National Institute of Radiological Sciences, Japan, the regional Central Reference Laboratory of the Reference Asian Man Project. The measured values of the uranium content were found to vary from 2.3 ng (g dry)(-1) to 11 ng (g dry)(-1). The geometric mean concentration and geometric standard deviation were 4.5 x//1.7 ng (g dry)(-1). This leads to a daily dietary intake of 2.6 x// 1.7 microg d(-1) or 33 x// 1.7 mBq d(-1), which is approximately 40% higher than the ICRP value. The measured value, i.e. 33 mBq d(-1), contributes 12 Bq y(-1) to annual intake of 238U activity and 0.54 microSv to the committed effective dose to the adult population. This is a very small fraction of the ICRP annual effective dose limit of 1 mSv for the general public. Therefore, it would pose no significant health hazard.

Diet↗

PubMed2002

Assessment of dietary zinc ingestion in Pakistan.

Zinc concentration was determined in the Pakistani diet with the use of instrumental neutron activation analysis. It varied from 12.94 to 37.77 microg/g, with an average value of 22.94 +/- 5.54 microg/g, indicating a daily intake of 13.59 +/- 3.31 mg/d for a reference Pakistani man weighing 63.9 kg. These values are comparable to those recommended by the International Commission of Radiological Protection for a man weighing 70 kg. We also found that the Pakistani diet contains zinc concentrations recommended by the U.S. Food and Nutrition Board and the International Commission of Radiological Protection.

Body Weight↗