Shaking behaviour induced by putrescine in naive rats: a pharmacological and histological study

In untreated rats, the intraperitoneal injection of putrescine evoked a typical wet-dog shake response, that was maximal at a dose of 300 mg/kg and at room temperature (22 degrees) (number of shakes: 84.00 +/- 17.90/hr). In a hot environment (30 degrees) the number of shakes was markedly reduced (26.90 +/- 5.19/hr). The putrescine-induced shaking behaviour was unaffected by atropine, bicuculline, chlorpheniramine, cimetidine, methysergide, naloxone and noradrenaline, but was markedly antagonized by morphine. Naloxone pretreatment nullified the antagonistic activity of morphine. Histological studies showed marked alterations in brain vascular permeability, which was increased by putrescine. Morphine completely prevented this putrescine-induced vascular effect. These results suggest a correlation between WDS produced by putrescine and increase in brain vascular permeability. Furthermore they show that morphine can affect brain vascular permeability.     

Experimental acute renal congestion in rat: histological observations

An experimental model of acute and total venous stasis has been realized in kidney of rat by division of the renal vein. Different grades of histological damage have been observed, from initial interstitial edema with only degenerative changes in tubular epithelium to its final necrosis. On the contrary glomeruli appear less involved.     

Acetyl-l-carnitine as possible drug in the treatment of hypothalamic amenorrhea.

Several neuroendocrine disregulations have been demonstrated in patients with hypothalamic amenorrhea, but a definite therapeutic strategy has not yet been found. Since acetyl-l-carnitine (ALC) has been reported to have a specific effect on central cholinergic, serotoninergic, dopaminergic and opioidergic systems, 20 patients with hypothalamic amenorrhea were treated with ALC (2 g/day, per os). Both the clinical efficacy and the endocrine parameters were evaluated after 6 months. The patients were subdivided in two groups according to their LH plasma levels: A) hypogonadotropic: 10 subjects with plasma LH less than 3 mIU/ml, and B) normogonadotropic: 10 subjects with plasma LH greater than 3 mIU/ml. All subjects underwent: 1) a pulsatility study (4 h sampling every 10 min), 2) GnRH test (two bolus injections of 10 micrograms at time 0 and +120), 3) TRH test (200 micrograms). These parameters were evaluated before and after 6 months of ALC administration. The occurrence of a spontaneous menstruation was observed in 6 out of 10 hypogonadotropinemic and in 4 out of 10 normogonadotropinemic patients. Menstrual bleeding occurred between the 3rd and the 6th month of therapy. Major hormonal changes after ALC administration were observed in the hypogonadotropic subjects. They showed a significant increase in baseline plasma LH levels (from 0.9 +/- 0.1 to 3.5 +/- 0.7 mIU/ml, p less than 0.05) (mean +/- SEM), a significant increase in LH pulse amplitude (p less than 0.01) with no changes in LH pulse frequency, and a significantly increased response of LH to the latter GnRH bolus during the GnRH test. Hypogonadotropic patients also showed a significant increase in both estradiol (from 18.8 +/- 2.5 to 48 +/- 3.3 pg/ml, p less than 0.05) and PRL (from 6 +/- 1 to 11.4 +/- 1.7 ng/ml, p less than 0.05). No significant differences were observed in the hormonal parameters of normogonadotropic patients after 6 months of ALC therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Two- versus three-dimensional imaging in subjects with unerupted maxillary canines

The aim of this study was to evaluate whether there is any difference in the diagnostic information provided by conventional two-dimensional (2D) images or by three-dimensional (3D) cone beam computed tomography (CBCT) in subjects with unerupted maxillary canines. Twenty-seven patients (17 females and 10 males, mean age 11.8 years) undergoing orthodontic treatment with 39 impacted or retained maxillary canines were included. For each canine, two different digital image sets were obtained: (1) A 2D image set including a panoramic radiograph, a lateral cephalogram, and the available periapical radiographs with different projections and (2) A 3D image set obtained with CBCT. Both sets of images were submitted, in a single-blind randomized order, to eight dentists. A questionnaire was used to assess the position of the canine, the presence of root resorption, the difficulty of the case, treatment choice options, and the quality of the images. Data analysis was performed using the McNemar-Bowker test for paired data, Kappa statistics, and paired t-tests. The findings demonstrated a difference in the localization of the impacted canines between the two techniques, which can be explained by factors affecting the conventional 2D radiographs such as distortion, magnification, and superimposition of anatomical structures situated in different planes of space. The increased precision in the localization of the canines and the improved estimation of the space conditions in the arch obtained with CBCT resulted in a difference in diagnosis and treatment planning towards a more clinically orientated approach.