MS-MS tandem mass spectrometeric studies of some nitropyridyl substituted phenyl ether derivatives

Nitro substituted pyridyl sulfide and amine derivatives were found to exhibit many fragmentation mechanisms a behaviour which is due to the high reactivity of nitropyridyl, nitro heterocyclic and nitro aromatic compounds. The most common mechanism in nitropyridyl derivatives is the ring closure through expulsion of nitrous acid molecule either by elimination of hydrogen and nitro radicals in two steps or a concerted mechanisms. Moreover, the elimination of nitrous acid molecule may occure via skeletal rearrangement of the molecular ion followed by successive loss of hydride and nitroside radicals to form a cyclic fragment. These mechanisms showed the importance of ortho effect, which favours the elimination of HNO2 molecule from the molecular ion. These mechanisms of ring closure could be confirmed on the basis of studied fragmentation processes by tandem mass spectrometry. It is usually used to propose the fragmentations pathways by following up the mass spectra produced from each individual ion

prevalence of hypertension in Saudi Arabia

Blood pressure [BP] is measured as part of a screening physical examination at the time of opening a family health record file in the Primary Health Care Centres [PHCC] of Almedina Almounawarah. We selectively screened Saudis in the 'high risk' age group [50-60 years]. The total number of the study sample was 1713: 1021 males, 692 females [24.3% of the target population]. They were recalled and had their BP measured again using standard methods. On the basis of a single reading, the BP was known in 1495 [20.8% of the target population: 880 [86.2%] of males 615 [88.8%] of females]. Hypertension, defined as receiving antihypertensive drug treatment or BP> 160/95 or both, was present in 10%, 6.8% and 14.6% of the total, male and female populations respectively. The percent period prevalence in subjects who had second BP readings was almost identical, there being an equal number of subjects with increased and decreased pressures. From the evidence we gathered, the prevalence of hypertension in Almedina Almounawarah is far less than that reported in British and American surveys. It is unknown whether other parts of the Kingdom have similar rates. Also it will be of great interest to evaluate, in future, the effects of a changing life-style, brought about by affluence, on the prevalence of hypertension