Effect of the menstrual cycle and oral contraceptives on aromatase and cyclooxygenase-2 expression in adenomyosis.

OBJECTIVES: To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle. PATIENT AND METHODS: This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods. RESULTS: Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle. CONCLUSION: Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase.     

The precision of positron emission tomography: theory and measurement

The limits of quantitation with positron emission tomography (PET) are examined with respect to the noise propagation resulting from radioactive decay and other sources of random error. Theoretical methods for evaluating the statistical error have been devised but seldom applied to experimental data obtained on human subjects. This paper extends the analysis in several ways: (1) A Monte Carlo method is described for tracking the propagation of statistical error through the analysis of in vivo measurements; (2) Experimental data, obtained in phantoms, validating the Monte Carlo method and other methods are presented; (3) A difference in activation paradigm, performed on regional CBF (rCBF) data from five human subjects, was analyzed on 1.6-cm diameter regions of interest to determine the mean fractional statistical error in PET tissue concentration and in rCBF before and after stereotactic transformation; and (4) A linear statistical model and calculations of the various statistical errors were used to estimate the magnitude of the subject-specific fluctuations under various conditions. In this specific example, the root mean squared (RMS) noise in flow measurements was about three times higher than the RMS noise in the concentration measurements. In addition, the total random error was almost equally partitioned between statistical error and random fluctuations due to all other sources.     

Impact of a specialized outpatient heart failure follow-up program on hospitalization frequency and functional status of patients with advanced heart failure.

BACKGROUND: High rates of morbidity and mortality are observed in patients with advanced heart failure (AHF). AHF is now considered the most costly syndrome in cardiology owing to the substantial economic burden associated with hospitalizations for acute decompensation. A management program that involves specialized follow-up by a multidisciplinary team has been suggested as a desirable strategy for improving outcomes for these patients. ObjectivE: To evaluate the impact of a specialized outpatient heart failure (HF) follow-up program for patients with AHF on frequency and duration of hospitalization for HF and functional status. METHODS: We retrospectively studied 167 consecutive patients with AHF who were referred to the outpatient HF follow-up program in our institution between January and November 2002, of whom 147 followed for > or =30 days were included in the analysis. In addition to demographic and baseline clinical characteristics, HF medication and NYHA functional class, the number and duration of hospitalizations for HF during the previous 12 months were recorded and compared at the time of referral and after a follow-up period of 6.5+/-3 months. RESULTS: Of the 147 patients analyzed (aged 60.8+/-13 years; 79% male; left ventricular ejection fraction 27+/-11%), 67% were in NYHA functional class III, 20% in class II and 13% in class IV at the time of referral. There was a significant improvement in functional class during the mean follow-up period: 55% of the patients were in class III, 37% in class II, 5% in class I and 3% in class IV (p<0.0001). The proportion of patients on beta-blockers or spironolactone increased from 33% and 51% at the time of referral to 69% and 71% respectively after referral (p<0.0001). In the 12 months before referral, 39% of the patients had been hospitalized for acute decompensation of HF (87 hospitalizations - mean 7.2/month) versus 13% of the patients during the mean follow-up period (25 hospitalizations - 3.8/month, p<0.0001). No significant differences were found in the proportion of patients on angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, digoxin or diuretics, or in the mean duration of hospitalization before and after referral. ConclusioN: The specialized follow-up of patients with AHF by a team with expertise in HF resulted in significant therapeutic optimization. Increased use of beta-blockers and spironolactone was associated with significant improvement in functional capacity and significant reduction in hospitalizations.     

Selective inactivation of mouse liver cytochrome P-450IIIA by cannabidiol

Cannabidiol (CBD) inhibits hepatic drug metabolism in mice, particularly those activities known to be catalyzed by the cytochrome P-450IIIA (P-450IIIA) subfamily. CBD treatment (120 mg/kg) inhibited more than 75% of hepatic 6 beta-testosterone hydroxylase and erythromycin N-demethylase activities (functional markers of P-450IIIA) after 2 hr. An isozyme of the P-450IIIA subfamily (Mr 49,960) was purified to apparent homogeneity from hepatic microsomes of untreated mice and was found to catalyze testosterone hydroxylation at the 2 beta-, 6 beta-, and 15 beta-positions exclusively. Incubation of this isozyme with CBD in a reconstituted system resulted in a time- and concentration-dependent inactivation, with almost complete loss of P-450 chromophore and corresponding increase in P-420 content. NH2-terminal sequence analysis of the isozyme revealed an 86% similarity to the corresponding sequence of rat P-450IIIA2, a constitutive P-450 isozyme in the male rat liver. Pretreatment of mice with dexamethasone markedly (6-fold) increased the steroid-inducible P-450IIIA-dependent activities 6 beta-testosterone hydroxylation and erythromycin N-demethylation. CBD treatment of dexamethasone-pretreated animals failed to inhibit these activities, indicating that the steroid-inducible P-450IIIA was refractory to CBD-mediated inactivation. 3-Methylcholanthrene-inducible P-450IA and phenobarbital-inducible P-450IIB also appear to be refractory to CBD-mediated inactivation. On the other hand, erythromycin N-demethylase activity increased 4-fold after phenobarbital pretreatment and, as in untreated animals, was comparably inhibited by CBD, demonstrating its susceptibility to this drug. Thus, CBD appears to inactivate the P-450IIIA isozymes that are constitutively present in hepatic microsomes of untreated mice and/or inducible by phenobarbital pretreatment but not those that are steroid inducible.     

Congenitally corrected transposition of the great arteries and aortic coarctation--an uncommon association.

Congenitally corrected transposition of the great arteries, L-TGA, is a rare abnormality accounting for less than 0.5% of clinically apparent congenital heart disease. Age at time of diagnosis and survival rate are variable and depend mostly on associated anomalies. The authors present a clinical case of a twenty-four-year-old woman in whom, in a routine echocardiogram, congenitally corrected transposition of the great arteries and aortic coarctation were diagnosed, an unusual association. They describe the results of complementary exams (echocardiography, chest X-ray, electrocardiogram and cardiac angiography) that they believe to be useful for the correct diagnosis of this clinical situation. Additionally, the authors make a brief review of the literature relevant to the case.     

Specifically designed thiosteroids as active-site-directed probes for functional dissection of rat liver cytochrome P450 3A isozymes.

Testosterone (T) 6 beta-hydroxylase (6 beta-OHase) is a well-recognized functional marker of rat liver cytochrome P450 3A (P450 3A) isozymes. Pretreatment of rats with inducers or specific or nonspecific inhibitors of P450 3A isozymes is associated not only with stimulation or inhibition of hepatic microsomal T 6 beta-OHase activity but also with parallel changes in the corresponding T 2 beta-, 15 beta-, and 18-OHase activities and T 4,6-diene formation. At the time these studies were conducted, no fully functionally active rat hepatic P450 3A isozymes had been isolated. To determine whether each of these activities was due to a single P450 3A isozyme, or whether multiple isozymes contributed to these activities, we specifically synthesized two thiotestosterone (6 beta- and 2 beta-SHT) analogues as potential mechanism-based inactivators of rat liver T 6 beta- and 2 beta-OHases. In addition, to assess their relative stereoselectivity, 2 alpha-SHT was also included as a control. Our studies revealed that although all three thiosteroids were excellent suicide substrates of P450 3A isozymes, they inactivated these T OHases differentially. Such differential inactivation and determination of the kinetic parameters of inactivation allowed the functional classification of rat hepatic P450 3A isozymes into at least two and possibly three categories: (i) forms (catalyzing 4,6-diene and 6 beta-OHT formation but with characteristically low 6 beta/2 beta-OHase ratios) highly susceptible to inactivation by SHTs; (ii) forms (catalyzing T 6 beta-, 2 beta-, 15 beta-, and 18-hydroxylations with high 6 beta-/2 beta-OHase ratios) moderately susceptible to the SHTs; and (iii) forms somewhat resistant to inactivation, at least at the SHT concentrations tested. Although no specific T OHase could be ascribed to a single P450 3A isozyme, it appears that each of these P450s catalyzed such T regiohydroxylations, albeit at considerably different extents. Furthermore, our studies also revealed that 2 alpha-SHT preferentially inactivated P450 3A forms but surprisingly failed to inactivate rat hepatic P450 2C11, thereby confirming the rather high substrate promiscuity of the P450 3A family of isozymes.     

Measurement of end-capillary PO2 with positron emission tomography

The analysis of positron emission tomography measurements of oxygen metabolism has been extended to provide a quantitative estimate of end-capillary PO2. The principle of this extension rests on the idea that the oxygen extraction fraction can be used to calculate the end-capillary oxygen saturation of the blood. The relation between oxygen saturation and PO2 is obtained through the oxygen dissociation curve. Our studies show that in addition to the local oxygen extraction fraction, arterial PO2 and pH values are needed in the calculation, whereas fairly large variations in factors such as PCO2, hematocrit, hemoglobin, and plasma protein levels have little or no effect. Rough estimates of end-capillary PO2 can be made using standard O2 dissociation nomograms. Blood gas and acid-base properties of blood have been known for decades, making it possible to account accurately for individual differences that may be encountered when studying patients. Measurements in nine normal subjects yielded a mean end-capillary PO2 value of 31.2 mm Hg. The ability to make a quantitative visualization of altered patterns of end-capillary PO2 provides an additional dimension to the investigation of stroke disease and tumor metabolism.     

Effect of converting enzyme inhibitors in cardiac insufficiency mortality in the elderly]

In a retrospective study we analyse two populations of aged patients in congestive heart failure, one treated with ACE inhibitors other not and the other with conventional therapy. Both populations received the same medication (diuretics and digitalis) and are equivalent in age, sex distribution, NYHA functional class and echocardiographic left ventricular parameters. Comparing the mortality of the two populations at the first, second and third year of follow-up, a statistically significant reduction in mortality was found on the ACE inhibitors treated population, at the first year. However, this reduction did not reach statistical significance at second and third years. The results are similar to trials in which the effects of ACE inhibitors are studied on general populations in heart failure.