Researchers within and outside China have suggested that large cities function as the most efficient center of growth or most powerful driving engine for China’s national development because of the operation of such natural market forces as the economies of scale and agglomeration. Zhou and Yang, for instance, have compared industrial economic returns among Chinese cities of different size and found that large cities outperformed their smaller counterparts [46]. Similar findings have been presented in other studies [40,47,48]. Based on these findings, it has been contended that the existing Chines
Botulism is the clinical term for the neuroparalytic disease caused by one of several protein toxins produced by Clostridium botulinum.
In spite of its relatively low rate of incidence, foodborne botulism is still considered a public health emergency due to its high mortality rate and the potential for widespread ingestion of contaminated foodstuffs [1]. The mortality rate has decreased to approximately 15% in the last 50 years [2] �D primarily due to improvements in supportive and respiratory care and to administration of antitoxin in the early stage of illness [3]. In spite of these improvements, the high lethality of these toxins has served as an inducement for nefarious activities, as evidenced by state-sponsored programs for their weaponization and two intentional releases of the toxins by the Aum Shinrikyo cult [4].The neurotoxins produced by C. botulinum exist as structurally similar but antigenically distinct serotypes.
Each toxin is synthesized as a 150 kDa polypeptide that is activated by proteolysis Dacomitinib and selective reduction, yielding a heavy chain (H, 100 kDa) and a light chain (L, 50 kDa) linked by an interchain disulfide. Regions of sequence homology suggest that all serotypes employ similar modes of action in neurotoxicity. The H chains provide cholinergic specificity. The L chains are zinc endopeptidases that cleave the SNARE proteins found in the presynaptic junction of neuronal cells at toxin-specific loci; cleavage of any of these SNARE proteins prevents release of acetylcholine, resulting in blockage of motor nerve terminals and flaccid paralysis. Botulinum neurotoxins are the most potent biological toxins in the world [5, 6]. By extrapolation from primate studies, the lethal amount of neurotoxin A toxin for a 70-kg human would be approximately 0.09-0.15 ��g delivered intravenously or intramuscularly, 0.70-0.90 ��g delivered by inhalation, and 70 ��g taken orally [5].The only currently approved test for laboratory confirmation of botulism and identification of a source food is the mouse bioassay, which can detect as little as 10 pg of neurotoxin [7, 8].