Hypothalamus-pituitary-adrenal modifications consequent to chronic stress exposure in an experimental model of depression in rats.

UNLABELLED: The modifications in the hypothalamus-pituitary-adrenal (HPA) axis function induced by repeated unavoidable stress exposure, according to a standardized procedure used for inducing an experimental model of depression, were studied. Rats exposed to this procedure show hyporeactivity to both pleasurable and aversive stimuli and this condition is antagonized by the repeated administration of classical antidepressant drugs. We also studied whether imipramine administration during stress exposure would interfere with the possible modifications in the HPA axis. Rats were exposed to a 4-week stress procedure with and without imipramine treatment and then tested for escape, as compared with non-stressed control animals. Twenty-four hours later all rats were bled through a tail nick for plasma corticosterone measurement before and after dexamethasone (10 microg/kg) or corticotropin-releasing hormone (CRH, 1 microg/kg) administration. Rats were then killed, adrenals and thymus weighed, brain areas dissected out and frozen for glucocorticoid receptors (GRs) and corticotropin-releasing hormone receptor 1 (CRHR1) immunoblotting and for the assessment of hypothalamic corticotropin-releasing hormone levels. RESULTS: Rats exposed to a 4-week unavoidable stress showed escape deficit and their basal plasma corticosterone levels were higher than those of control animals. Moreover, they had decreased response to dexamethasone administration, adrenal hypertrophy, and decreased GR expression in the hippocampus, hypothalamus, medial prefrontal cortex and pituitary. No significant modifications in CRHR1 expression were observed in the pituitary nor in different discrete brain areas. CRH levels in the hypothalamus and the plasma corticosterone response to CRH administration were found to be higher in stressed rats than in controls. Imipramine treatment offset all the behavioral and neurochemical stress-induced modifications. In conclusion, the present results strengthen the assumption that the escape/avoidance behavioral deficit induced by inescapable stress exposure is accompanied by steadily increased HPA activity, and that imipramine effect is strongly related to a normalization of HPA axis activity.

Extracorporeal shock wave lithotripsy in ureteral and kidney malformations.

INTRODUCTION: Extracorporeal shock wave lithotripsy (SWL) has long been accepted worldwide in the treatment of kidney stone disease. Upper ureter calculi in ureteral and kidney malformations are rather frequent (10-25%). The aims of this retrospective study were to determine whether malformations might impair fragment expulsion. MATERIAL AND METHODS: From 1986 to 1995, 203 patients with ureteral and kidney malformations were treated and followed up for a minimum of 1 year to a maximum of 9 years. Malformations included: ureteropelvic junction stenosis, horseshoe kidney, renal malrotation, renal ectopia, duplicated ureter, nonobstructive megaureter, medullary sponge kidney and caliceal diverticula. As pretreatment workup, all patients underwent conventional studies prior to SWL treatment: X-rays, renal ultrasound, intravenous pyelography, routine blood tests and urinalysis. All examinations were repeated at regular intervals for the first 6 months. Patients with metabolic disorders were excluded from the study. We also excluded patients with a follow-up of under 1 year. We considered three groups of patients: (1) stone-free patients at plain X-rays and ultrasound; (2) >90% elimination, i.e. stone-free patients at plain X-rays and positive at ultrasound; (3) patients with residual fragments at plain X-rays and ultrasound. RESULTS: 96 (55%) patients were in group 1 (stone free), 40 (19%) were in group 2 (>90% elimination) and 67 (26%) were in group 3 (residual). Residual stones were more frequent in patients with medullary sponge kidney (82%). In patients with renal ectopia the residual stone rate accounted for only 13% of cases. CONCLUSIONS: There is evidence that SWL should always be offered to patients with ureteral and kidney malformations. These patients should however be considered at high risk for recurrences and so they need to be carefully followed up.