Lack of difference between retinoic acid and retinol in stimulating progesterone production by luteinizing granulosa cells in vitro

Receptors for retinoids in the immature rat ovary and the effects of retinol and retinoic acid on luteinizing granulosa cells were studied. Radioreceptor assay demonstrated the presence of specific cellular retinol-binding protein and cellular retinoic acid-binding protein in the ovaries of rats injected with PMSG alone or PMSG and hCG. In addition, when luteinizing granulosa cell from PMSG/hCG-injected immature rats were cultured with or without retinoic acid, the morphology, viability, number of cells in culture, and progesterone (P) accumulation were not affected by up to 10 microM retinoic acid. Beyond 10 microM, the cells began to round up, which was associated with a decrease in cell viability. Surprisingly, the deleterious concentrations of retinoic acid increased progesterone accumulation significantly higher than the medium control value. This increase in progesterone, however, was not accompanied by an increase in cAMP. When cells preincubated for 2 days with 1 microM of either retinoic acid or retinol were subsequently incubated in retinoid-free medium containing various substrates for steroidogenesis, the following results were obtained. Basal progesterone and its accumulation in response to human low density lipoprotein were significantly higher in cells preincubated with retinoids than in the control cells. However, no difference was seen in the degree of stimulation between retinol and retinoic acid pretreatments. Both 25-hydroxycholesterol, a substrate for side-chain cleavage enzyme, and pregnenolone, a substrate for 3 beta-hydroxysteroid dehydrogenase, significantly stimulated the accumulation of progesterone in cells preincubated with retinoids over the control value. Again, no appreciable difference was observed between retinol and retinoic acid pretreatments. Our results suggest that receptors for retinoids are present in gonadotropin-primed immature rat ovaries, retinoids increase luteal cell progesterone accumulation, and no difference exists between retinol and retinoic acid in their ability to increase the accumulation of progesterone by these cells.     

Expression of CYP1B1 but not CYP1A1 by primary cultured human mammary stromal fibroblasts constitutively and in response to dioxin exposure: role of the Ah receptor

The expression of CYP1B1 in human mammary fibroblasts (HMFs) was characterized as a potential modulator of their individual function as well as effects on adjacent mammary epithelia. We have used these characteristics to explore the diversity of fibroblast cells isolated from reduction mammoplasty patients and from different breast locations in breast cancer patients (tumors, peripheral to tumor and skin). These parameters have also been used to examine differences between two donors. The results have shown that while none of these HMFs expressed a detectable CYP1A1 protein basally or in response to TCDD, they all expressed CYP1B1 constitutively at similar levels (0.5-0.9 pmol/mg microsomal proteins) and they were induced by TCDD (up to 5-fold) consistent with mediation by the Ah receptor (AhR). DMBA metabolism by HMFs exhibited high proportions of 5,6-, 10,11- and 3,4-dihydrodiols, a profile that is typical of human CYP1B1 regioselectivity. RT-PCR followed by Southern blot analyses demonstrated that CYP1B1 mRNA expression in HMFs parallels levels of respective microsomal proteins. The AhR is expressed in these HMFs as two cytosolic forms (approximately 106 and 104 kDa) and a substantial proportion of the 104 kDa form was localized to the nucleus even prior to TCDD treatment. In all HMFs isolated directly from collagenase digested breast tissues the AhR is expressed at levels 10-fold lower than in breast epithelial cells. However, HMFs that were isolated after serial passaging of mammary epithelial cultures had shown much higher levels of the AhR expression and more dramatic TCDD-induced down-regulation (>80% in 24 h) associated with more efficient nuclear translocation. These differences suggested the presence of two functionally distinct subtypes of HMFs: interstitial stromal fibroblasts that are readily released by collagenase digestion of breast tissues, and lobular stromal fibroblasts which are more tightly associated with the breast epithelia.      

Long-segment femoropopliteal stenoses: is angioplasty a boon or a bust?

Analysis of 193 femoropopliteal angioplasties demonstrated patency rates in the stenotic group of 75.5% at 6 months and 54.4% at 54 months. The patency rates for the occlusive group were 93.7% at 6 months and 72.9% at 54 months; these rates were significantly better than those in patients with stenoses. A group of 14 patients with long-segment (greater than 7 cm) stenosis had the highest risk of early failure, with a 6-month patency of 23.1%. After removal of the long-segment stenosis group from the results, there were no significant differences between the long-term patencies for stenotic and occlusive lesions. If angioplasty of long stenoses is attempted, a high initial success rate but early failure should be anticipated.     

Scintigraphy in laryngopharyngeal and gastroesophageal reflux disease: A definitive diagnostic test?

AIM: To investigate the utility of scintigraphic studies in predicting response to laparoscopic fundoplication(LF) for chronic laryngopharyngeal reflux symptoms.METHODS: Patients with upper aero-digestive symptoms that remained undiagnosed after a period of 2 mo were studied with conventional p H and manometric studies. Patients mainly complained of cough, sore throat, dysphonia and globus. These patients were imaged after ingestion of 99m-technetium diethylene triamine pentaacetic acid. Studies were quantified with time activity curves over the pharynx, upper and lower oesophagus and background. Late studies of the lungs were obtained for aspiration. Patients underwent LF with post-operative review at 3 mo after surgery.RESULTS: Thirty four patients(20 F, 14 M) with an average age of 57 years and average duration of symptoms of 4.8 years were studied. Twenty four hour p H and manometry studies were abnormal in all patients. On scintigraphy, 27/34 patients demonstrated pharyngeal contamination and a rising or flat pharyngeal curve. Lung aspiration was evident in 50% of patients. There was evidence of pulmonary aspiration in 17 of 34 patients in the delayed study(50%). Pharyngeal contamination was found in 27 patients. All patients with aspiration showed pharyngeal contamination. In the 17 patients with aspiration, graphical time activity curve showed rising activity in the pharynx in 9 patients and a flat curve in 8 patients. In those 17 patients without pulmonary aspiration, 29%(5 patients) had either a rising or flat pharyngeal graph. A rising or flat curve predicted aspiration with a positive predictive value of 77% and a negative predictive valueof 100%. Over 90% of patients reported a satisfactory symptomatic response to LF with an acceptable sideeffect profile. CONCLUSION: Scintigraphic reflux studies offer a good screening tool for pharyngeal contamination and aspiration in patients with gastroesophageal reflux disease.