Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0599766 (functional recovery)
 13,441 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The time-dependent recovery of gonadotropin-releasing hormone (GnRH) responsiveness in desensitized gonadotropes was examined under conditions of altered membrane fluidity and GnRH exposure. Cultured pituitary cells were treated for 3 h with GnRH (10(-9) M; to provoke homologous desensitization) or vehicle alone (controls). When cells were washed and immediately rechallenged for 3 h with GnRH, gonadotrope responsiveness (assessed by luteinizing hormone (LH) release) was significantly lower in GnRH-pretreated cells than controls. If gonadotropes were allowed to recover in medium alone, membrane fluidity agents 2-(2-methoxyethoxy)-ethyl-8-(cis-2-n-octylcyclopropyl)-octanoate (A2C; 10(-4) M) or cis-vaccenic acid (CVA; 0.5 mM) or a low dose of GnRH (10(-10) M) for up to 48 h prior to rechallenging with GnRH, responsiveness in all cases was significantly lower in GnRH-pretreated cells than controls. However, if cells were treated with either A2C or CVA in the presence of GnRH (10(-10) M) during the recovery period, gonadotrope responsiveness to a subsequent challenge with GnRH was partially restored by 24 h; by 48 h no differences in the LH secretory response to GnRH was detected between GnRH-pretreated cells and controls. The possibility that restoration of the GnRH receptor-linked Ca2+ channel is associated with recovery of the desensitized gonadotrope was also examined. Identical protocols to those described above were used except that the functional integrity of the Ca2+ channel was assessed by measuring LH release in response to increasing doses of maitotoxin (MTX; a specific Ca2+ channel activator). Again, GnRH-pretreated cells were significantly less responsive to MTX than controls when allowed to recover for 48 h in medium alone, A2C (10(-4) M) or GnRH (10(-10) M). However, allowing cells to recover for 48 h under a condition of increased membrane fluidity and basal GnRH levels completely restored the MTX-stimulated LH secretory response in GnRH-pretreated gonadotropes. Taken together, these studies suggest that the physical state of the gonadotrope plasma membrane together with the appropriate hormonal milieu provide an important environment for the gonadotrope to recover from desensitization. Additionally, our results suggest that functional recovery of the GnRH-linked Ca2+ channel may play a requisite role in restoring GnRH responsiveness to the desensitized gonadotrope.
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PMID:Restoration of the LH secretory response in desensitized gonadotropes. 284 35

From January 1989 through June 1996, 29 patients underwent surgical repair of type A acute aortic dissection. Mean age was 59 +/- 13.5 years (range 25-76 yrs) and 21 patients (72.4%) were male. Nineteen patients (65.5%) had systemic hypertension and 3 (10.3%) Marfan syndrome. One patient (3.4%) had prior surgical repair of descending aortic dissection and CABG. Six patients (20.7%) were operated on in shock. The dissection was limited to the ascending aorta (DeBakey type II) in 12 patients (41.4%). Eleven patients (37.9%) had severe aortic regurgitation. Replacement of the ascending aorta was performed in all cases and extended to include the transverse arch in one. Twenty-three patients (79.3%) were operated upon using a tubular graft (sacron-21, homograft-2) with aortic valve resuspension. In the remaining 6 (20.7%) the aortic valve and root were replaced using a Bentall procedure, modified with a homograft in 3 cases. Five patients (17.2%) had associated surgery: CABG (4) and closure of aortic-atrial fistula (1). Mean cardiopulmonary bypass time was 134 minutes (range 70 to 285 min) and aortic cross-clamp time was 58 minutes (range 23 to 93 min). Hypothermic circulatory arrest for open distal anastomosis was used in 26 patients (89.7%) (mean time 22 min; range 10 to 32 min), with retrograde cerebral perfusion in the last 4 years (18 cases; 62.1%). Hospital mortality was 17.2% (5 patients). Eight patients (27.6%) had hospital morbidity: reexploration for bleeding (4 cases), CVA (3), A-V block necessitating permanent pacemaker (1). The mean time of hospitalization was 18 days (range 9 to 81 days). In the follow-up period (mean 38 mths; range 4 to 94 mths), 2 patients died (CVA and gastrointestinal bleeding) and 4 required hospitalization (perforated duodenal ulcer, peritonitis, suspected endocarditis, supraventricular tachyarrhythmia-1 patient each). All 22 survivors (75.9%) returned to the functional status they had prior to the dissection and 18 of them (81.8%) are in NYHA functional class I. Type A acute aortic dissection is a complex pathology and the postoperative mortality remains significant, but surgery permits good functional recovery and an active life for the survivors.
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PMID:[Surgery for acute type-A aortic dissection]. 930 6