The establishment of national diagnostic reference levels for adult SPECT-CT in Saudi Arabia.

This study aims to introduce national diagnostic reference levels (NDRLs) for adult hybrid single photon emission computed tomography (SPECT-CT) in nuclear medicine (NM) departments in the Kingdom of Saudi Arabia. The administered activity (AA) of radiopharmaceuticals, volume-weighted computed tomography dose index (CTDIvol) and dose length product (DLP) for ten hybrid SPECT/CT examinations were collected and analysed for one year. The median of AA, CTDIvoland DLP for each dose quantity was derived and the suggested national DRLs were determined based on the 75thpercentile for all identified SPECT-CT examinations. A comparison of the defined adult NDRLs in Saudi Arabia with the published data of other countries was performed. Although there are no significant variations of the proposed NDRL of AA between countries, the proposed NDRLs of the integrated CT metrics exceed the published data in most procedures. NM departments are urged to consider optimisation for both image quality and radiation protection.

Green Synthesis of Silver Nanoparticles Using Aerial Part Extract of the Anthemis pseudocotula Boiss. Plant and Their Biological Activity.

Green syntheses of metallic nanoparticles using plant extracts as effective sources of reductants and stabilizers have attracted decent popularity due to their non-toxicity, environmental friendliness and rapid nature. The current study demonstrates the ecofriendly, facile and inexpensive synthesis of silver nanoparticles (AP-AgNPs) using the extract of aerial parts of the Anthemis pseudocotula Boiss. plant (AP). Herein, the aerial parts extract of AP performed a twin role of a reducing as well as a stabilizing agent. The green synthesized AP-AgNPs were characterized by several techniques such as XRD, UV-Vis, FT-IR, TEM, SEM and EDX. Furthermore, the antimicrobial and antibiofilm activity of as-prepared AP-AgNPs were examined by a standard two-fold microbroth dilution method and tissue culture plate methods, respectively, against several Gram-negative and Gram-positive bacterial strains and fungal species such as Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), multidrug-resistant Pseudomonas aeruginosa (MDR-PA) and Acinetobacter baumannii (MDR-AB), methicillin-resistant S. aureus (MRSA) and Candida albicans (C. albicans) strains. The antimicrobial activity results clearly indicated that the Gram-negative bacteria MDR-PA was most affected by AgNPs as compared to other Gram-negative and Gram-positive bacteria and fungi C. albicans. Whereas, in the case of antibiofilm activity, it has been found that AgNPs at 0.039 mg/mL, inhibit biofilms formation of Gram-negative bacteria i.e., MDR-PA, E. coli, and MDR-AB by 78.98 ± 1.12, 65.77 ± 1.05 and 66.94 ± 1.35%, respectively. On the other hand, at the same dose (i.e., 0.039 mg/mL), AP-AgNPs inhibits biofilm formation of Gram-positive bacteria i.e., MRSA, S. aureus and fungi C. albicans by 67.81 ± 0.99, 54.61 ± 1.11 and 56.22 ± 1.06%, respectively. The present work indicates the efficiency of green synthesized AP-AgNPs as good antimicrobial and antibiofilm agents against selected bacterial and fungal species.

Distinct anti-proliferative effects of herbal melanin on human acute monocytic leukemia THP-1 cells and embryonic kidney HEK293 cells.

BACKGROUND: Herbal melanin (HM) is a dark pigment extracted from the seed coat of Nigella sativa L. and known to exert biological effects via toll-like receptor 4 (TLR4). Recently, TLR4 was described as involved in natural programmed cell death (apoptosis). Tumor and embryonic cells are used as in vitro cellular models for drug and anti-cancer agent screening. To date, no cytotoxic studies have been reported of HM in TLR4-positive acute monocytic leukemia THP-1 cells compared to TLR4-negative human embryonic kidney HEK293 cells. METHODS: We studied the anti-proliferative effects of several HM concentrations on THP-1 and HEK293 cells by evaluating cell viability using the CellTiter-Glo® luminescent assay, assessing the TLR4 expression level, determining the apoptotic status, and analyzing the cell cycle distribution using flow cytometry. Apoptotic pathways were investigated using mitochondrial transition pore opening, caspase activity assays and immunoblot technology. RESULTS: Low HM concentrations did not affect THP-1 cell viability, but high HM concentrations (62.5-500 µg/mL) did decrease THP-1 cell viability and induced G0/G1 phase cell cycle arrest. Only at the highest concentration (500 µg/mL), HM slightly increased the TLR4 expression on the THP-1 cell surface, concomitantly upregulated TLR4 whole protein and gene expression, and induced apoptosis in THP-1 cells via activation of the extrinsic and intrinsic pathways. No change of apoptotic status was noticed in TLR4-negative HEK293 cells, although HM decreased HEK293 cell viability and induced cell growth arrest in the G2 phase. CONCLUSION: HM exerts distinct anti-proliferative effects on human acute monocytic leukemia and embryonic kidney cells mainly through cell cycle interference in a TLR4-independent manner and through apoptosis induction in a TLR4-dependent manner, as observed in only the THP-1 cells.

New findings: a very high natural radiation area in Afra hot springs, Jordan.

A high natural radiation zone was investigated for the first time in Afra hot springs of Jordan. The radiation levels were measured using a portable Geiger-Muller counter and an Na(Tl) detector. The measured absorbed dose rates in air ranged from 10 to 1800 nGy h(-1), suggesting that the concentration of natural radioactive materials is very high compared with their normal abundance in crustal rocks. A single high-radiation zone was also found in a nearby area where a gamma radiation dose rate of 4.0 mGy h(-1) was measured. On the basis of this measurement, the area was marked as a high-radiation zone. This region is far from tourist areas and not easily reached. No intervention measures are needed to protect people because the spa area is not well inhabited, having only daily visitors (average frequency of 10 days per year per individual). The dose received by workers in the spa area should be considered and the worker should be monitored by personal radiation dosimeters, such as thermoluminescent dosimeters.

Fractional-calculus diffusion equation.

BACKGROUND: Sequel to the work on the quantization of nonconservative systems using fractional calculus and quantization of a system with Brownian motion, which aims to consider the dissipation effects in quantum-mechanical description of microscale systems. RESULTS: The canonical quantization of a system represented classically by one-dimensional Fick's law, and the diffusion equation is carried out according to the Dirac method. A suitable Lagrangian, and Hamiltonian, describing the diffusive system, are constructed and the Hamiltonian is transformed to Schrodinger's equation which is solved. An application regarding implementation of the developed mathematical method to the analysis of diffusion, osmosis, which is a biological application of the diffusion process, is carried out. Schrödinger's equation is solved. CONCLUSIONS: The plot of the probability function represents clearly the dissipative and drift forces and hence the osmosis, which agrees totally with the macro-scale view, or the classical-version osmosis.

Interpretation of fission product effects on human body.

The behaviors of fission products is studied in this study with the principal objective of making a comparison between Deep Atomic Binding (DAB) Approach and other models used to interpret the health effects of fission products on human body. Large numbers of fatalities, malignancies, thyroid cancer, born (genic) defects were predicted as health effects of fission products on human body. Nevertheless, the facts after real releases of fission products were not consistent with what was predicted. DAB Approach interprets these facts and reduces radiophobia as well as radiation protection expenses.