[Mechanism of paraoxon Effect on [[3]H] GABA uptake inhibition in brain synaptosomes of rat]

Parathion is an organophosphate compound that is frequently used as an insecticide. Paraoxon is the metabolic product of parathion which previously reported that inhibits GABA uptake by rat cerebral cortex synaptosomes. The aim of this study is to investigate possible underlying inhibitory mechanism[s] of paraoxon on GABA uptake, in synaptosomes prepared from rat cerebral cortex. After preparation of synaptosomes, kinetic studies were performed to determine the effect of paraoxon on K[m] and V[max] of GABA uptake. Acetylcholine and its antagonists [atropine and mecamylamine] were used to evaluate cholinergic dependency of GABA uptake. Type of GABA transporter involved was determined using beta-alanine and DAB A. The results of the study showed that paraoxon significantly decreased V[max] [175.2 +/- 4.23 vs. 80.4 +/- 2.03 pmol/mg protein/min, P<0.001] of GABA uptake while had no effect on its k[m] [9.80 +/- 1.02 vs. 9.09 +/- 0.92micro M in paraoxon and control groups respectively]. DABA significantly decreased GABA uptake [P<0.001] while beta-alanine had no effect. Acetylcholine had no effect on GABA uptake. On the other hand, neither atropine nor mecamylamine could reverse the inhibitory effect of paraoxon on GABA uptake. In conclusion, it seems that paraoxon acts as non-competitive anatagonist of GABA uptake, which affects kinetics of GABA uptake in nerve endings. We also conclude that the inhibitory effect of paraoxon on GABA uptake is cholinergic-independent

Validation of the West Haven-Yale Multidimensional Pain Inventory [WHYMPI] for Iranian patients with chronic pain

This study aimed to validate the West Haven-Yale Multidimensional Pain Inventory [WHYMPI] for Iranian patients with chronic pain. 585 patients with chronic pain in legs, back, hands, neck and shoulders were entered into this study. The West Haven-Yale Multidimensional Pain Inventory [WHYMPI] was used for assessment of pain in these patients. For validation of this inventory the results were compared with those obtained from Brief Pain Inventory [BPI], Beck Depression Inventory [BDI], State Trait Anxiety Questionnaire and Enrich marriage inventory. Using Cronbach's alpha, validity of the first section of WHYMPI was 0.86, the second section was 0.78, and the third section was 0.75. The Test-retest correlation was 0.95. Also, the correlation of each individual section with the whole inventory was positive and significant. The results indicate that modified form of the West Haven-Yale multidimensional Pain Inventory [WHYMPI] can be used in Iran

[Frequency and pattern of diabetes insipidus following hypophyseal adenectomy in Baqyiatallah hospital, 1991-2001]

Adenoma is one of the most common pituitary tumors, with diabetes Insipidus [DI] being one of the most common complications. This study was conducted with the following aims: a] determination of relative frequency of DI following hyphophyseal adenectomy, b] assessment of correlation between DI and some variables, c] study the clinical course of DI development after surgery of hyphophyseal adenoma. Matherials and This prospective study was conducted between 1991-2001 in Baqyiatallah Hospital, Tehran, 50 Patients with pituitary adenoma without diabetes underwent trans-Sphenoidal [n = 35] or trans-cranial adenectomy [n = 15]. Development, time of onset, duration of DI, and need to use Minirin was assessed in patients. DI was categorized to Immediate DI [IDI, day 10]. DI occurred in 15 cases [30%], of which, 10 had IDI [67%] and 5 cases had DDI [33%]. DI developed in 5 [33.3%], 7 [46.6%], and 1 [6.6%] subjects, on days 1, 2 and 7 following their operation, respectively. DI was not correlated with sex, age and kind of surgery [p>0.05]. DDI was seen more after trans-Cranial surgery than after trans-Sphenoid surgery [26.6% vs 2.8%, p=0.024]. Of 15 cases of DI, 5 [33%] did not need Minirin, 5 [33%] needed it just for one day, and 5 [33%] received it for 4-180 days [4, 11, 15, 62 and over 180 days]. This study reported the relative frequency of hypophyseal adenectomy to be 33%. According to this study, one third of patients have self-limited DI and do not need drug therapy. However, we recommend that in patients with DI after these surgeries, early and routine prescription of Minirin should be avoided and treatment should be based on fluid replacement. This study also reported trans-Sphenoid surgery to be less frequently accompanied by DI, which seems to be an important factor in the selection of operation techniques for these surgeries