Interaction of Androgens with Cardiotonic Drugs in Isolated Left Atrium of Rat

Pharmacological concentrations of androgens are known to elicit a rapid positive inotropism in isolated left atrium of male rats. Upon short-term exposure to androgens, an increase in intracellular cAMP levels has been observed, though delayed with respect to the time course of contraction, suggesting that other mechanisms may participate in initiating the contraction. Therefore, the interaction of positive inotropism elicited by ouabain, an inhibitor of Na(+)-K(+)-ATPase, and androgens was studied in isolated left atrium of rat. Androgens antagonized ouabain-elicited positive inotropism and increased the basal tone. Vanadate, an inhibitor of the Ca(2+) pump, produced a similar effect as androgens on ouabain-elicited positive inotropism. Therefore, androgens might interact with the Ca(2+) pump and this may explain the increase in basal tone. The conjugation of 5 alpha-dihydrotestosterone with bovine serum albumin produced the same effect, suggesting an extracellular interaction of androgens inhibiting the Na(+)-K(+)-ATPase that could increase intracellular Ca(2+) via the Na(+)-Ca(2+) exchange.

Unprotected left main coronary artery stenting: correlates of midterm survival and impact of patient selection

BACKGROUND

The study served to present the in-hospital and six-month clinical outcome and also the long-term survival data of a consecutive series of patients undergoing stenting for unprotected left main coronary artery (LMCA) disease.

METHODS

Revascularization with coronary bypass surgery has been generally recommended for treatment of left main coronary stenosis. Improvements in angioplasty and coronary stent techniques and equipment may result in the wider applicability of a percutaneous approach. A total of 92 consecutive patients underwent unprotected LMCA stenting between March 1994 and December 1998. For the initial 39 patients (group I) angioplasty was performed only when surgical revascularization was contraindicated. The remaining 53 patients (group II) also included patients in whom surgery was feasible. Patients were followed for 7.3 +/- 5.8 months (median 239 days; range 49 to 1,477 days).

RESULTS

Compared to group I, group II patients had higher left ventricular ejection fraction (60 +/- 12% vs. 51 +/- 16%, p < 0.01), less severe LMCA stenosis (68 +/- 12% vs. 80 +/- 10%, p < 0.001), lower surgical risk score (13 +/- 7 vs. 20 +/- 7, p < 0.001), and had angioplasty more often performed via the radial approach (88% vs. 23%, p < 0.001) with smaller guiding catheters (6F: 49% vs. 15%; 8F: 2% vs. 77%, p < 0.001). The procedural success rate was 100%. In-hospital mortality was 4% (4 deaths, 3 cardiac). During follow-up there were six deaths, 13 patients required repeat percutaneous transluminal coronary angioplasty (4 LMCA), and two required coronary artery bypass graft surgery. Estimated survival (+/- SEE) was 89 +/- 6.3% at 500 days and 85 +/- 12% at 1,000 days post-stenting. Overall mortality was 3.8% in group II and 20.5% in group I (p < 0.02).

CONCLUSIONS

Coronary stenting can be performed safely in high-risk individuals with acceptable intermediate-term outcome. It may be feasible to broaden the application of this technique in selected patients needing revascularization for left main coronary disease.

In-stent restenosis: long-term outcome and predictors of subsequent target lesion revascularization after repeat balloon angioplasty

OBJECTIVES

We sought to evaluate the long-term clinical outcome of patients undergoing successful balloon angioplasty for in-stent restenosis, and to determine correlates of the need for subsequent target lesion revascularization (TLR).

BACKGROUND

In-stent restenosis can be safely treated by repeat percutaneous intervention. Reported subsequent TLR rates have varied from 20% to 80% and seem related to the type of restenotic lesion.

METHODS

The study population comprised 234 patients with follow-up data who were successfully treated with repeat balloon angioplasty for in-stent restenosis in 257 lesions between May 1995 and January 1998 at our institution.

RESULTS

Clinical follow-up was available at 459 (286 to 693) days after the repeat procedure. Event-free survival was 78.5% and 74.6% at 12 and 24 months, respectively. Recurrent events occurred in 58 patients (24.8%), including 6 deaths (2.6%), 4 myocardial infarction (1.7%) and repeat target vessel revascularization in 50 patients (21.4%). Independent predictors of repeat TLR were time to in-stent restenosis <90 days (Hazard ratio 4.67, p < 0.001), minimal luminal diameter after repeat procedure (Hazard ratio 0.38, p = 0.034) and the angiographic pattern of in-stent restenosis (Hazard ratio 1.65, p = 0.036).

CONCLUSIONS

Balloon angioplasty is an effective means of treating in-stent restenosis. The long-term results are acceptable particularly for focal restenotic lesions. Further restenosis is more common in patients with early initial recurrence, more proliferative lesions and a poorer angiographic result from repeat angioplasty.

Role of c-myc in tamoxifen-induced apoptosis estrogen-independent breast cancer cells

BACKGROUND

The antiestrogen tamoxifen (TAM) is effective in the treatment of estrogen receptor (ER)-positive as well as some ER-negative breast cancers. However, the precise mechanism of action of TAM, especially in estrogen-independent cells, remains unclear. Previous work by our laboratory has demonstrated that TAM induces the morphologic and biochemical changes that are characteristic of apoptosis in both ER-positive and ER-negative cells.

PURPOSE

We compared the effect of TAM at a clinically achievable concentration on cell growth and apoptosis with the effect of TAM on c-myc (also known as C-MYC) messenger RNA (mRNA) and protein expression in ER-negative MDA-231 cells.

METHODS

MDA-231 cells were treated for up to 72 hours with 1.0 microM TAM alone or in the presence of 50 microM c-myc antisense or nonsense oligonucleotides. c-myc mRNA expression was determined by northern blot analysis, protein expression by western blot analysis, cell growth inhibition counts, and DNA cleavage by agarose gel electrophoretic analysis. Differences between the mean values from different treatment groups were compared with the use of the two-sided Wilcoxon Ranksum test.

RESULTS

TAM treatment for 72 hours increased c-myc mRNA five-fold (from a relative radiolabeled hybridization signal intensity of 17 +/- 4 up to 93 +/- 10; P<.05) and c-MYC protein threefold (from a relative immunofluorescence signal intensity of 28 +/- 7 up to 83+/-21; P< .05). The induction of c-myc by TAM was accompanied by internucleosomal DNA cleavage characteristic of apoptotic cell death. Addition of c-myc antisense oligonucleotide (5'CACGTTGAGGGGCAT-3') to MDA-231 cells resulted in a nearly twofold decrease of basal c-myc mRNA (P< .05) and a sevenfold decrease of basal c-Myc protein (P< .05) expression. Addition of c-myc antisense oligomer also antagonized the TAM-induced increase in c-myc mRNA (P< .05) and protein expression (P< .05) and inhibited TAM-induced cytostasis (P< .01) and apoptosis. In parallel experiments, addition of the nonsense oligomer had no effect on any of the measured parameters.

CONCLUSIONS

These results indicate that the effects of TAM on ER-negative MDA-231 cells may be mediated through c-myc overexpression. c-myc may play a critical role in the growth and progression of MDA-231 breast cancer cells.

Adaptation mechanisms during myocardial ischemia in chronic unstable angina pectoris

Unstable angina with a clinical duration of < 2 months is characterized angiographically by a high incidence of complex lesions. Some patients have ischemic rest pain syndromes of longer duration. Thus, we retrospectively analyzed, in blinded fashion, the clinical and angiographic findings in 52 patients with unstable angina of < 2 months' duration (group A), and compared the results with those of 32 patients with unstable angina of > 6 months' duration (group B). Group B had a greater number of diseased vessels and better collateral circulation, but had fewer eccentric lesions. There were no differences in age, left ventricular function, or history of prior myocardial infarction. Thus, chronic unstable angina is associated with more extensive coronary disease than unstable angina of shorter duration. The role of different anatomic substrata and collateral circulation is discussed.

Prevalence and upper limit of cardiac hypertrophy in professional cyclists

The term athlete's heart refers to an increased left ventricular mass. Few studies have assessed the prevalence and normal upper limit of cardiac hypertrophy in highly trained cyclists and this was the aim of this study. A group of 40 professional road cyclists [mean age 26 (SD 3) years] who had participated in European competitions for 3-10 years, were evaluated at the beginning of the 1992-93 season. Evaluation included a clinical history and physical examination, one and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. Systolic and diastolic blood pressure were measured at rest and at peak exercise. Of the group 23 cyclists (58%) presented a LVMI greater than 130 g.m-2, 21 cyclists presented a diastolic ventricular thickness equal to or greater than 13 mm, with a superior limit of 19 mm; 3 cyclists presented asymmetrical septum hypertrophy; and the relationship between posterior wall and left ventricular diastolic radius was equal to or greater than 0.45 in 14 cases (35%). Electrocardiographic abnormalities of ST-T segment were seen in only 1 subject. No correlation was found between the degree of ventricular hypertrophy and arterial blood pressure. We concluded that these professional cyclists showed a high prevalence of cardiac hypertrophy (58%). The distribution of this hypertrophy was concentric in 20/33 and asymmetric in 3/23 of the subjects with left ventricular hypertrophy. The electrocardiograms were normal in 98% of the subjects.

Management and prognosis of adenocarcinoma of the appendix

PURPOSE

Adenocarcinoma of the appendix is a rare neoplasm, and controversies persist regarding management. The purpose of this study was to identify prognostic factors and define management strategies for patients with adenocarcinoma of the appendix.

METHODS

A retrospective case series was conducted at three medical school teaching hospitals over a 20-year period from 1972 to 1992. Overall survival was determined by the actuarial life table method. Comparisons of prognostic factors were made using exact nonparametric log-rank tests.

RESULTS

Thirteen patients were diagnosed during the study period. Median age was 62 years. There were five males and eight females. The disease was not suspected in any patient preoperatively. Seventy-seven percent of patients had metastatic disease at presentation. Second primary malignancies were found in 15 percent of patients. Thirty-eight percent of female patients had synchronous ovarian lesions. Median survival was 22 months, with an estimated five-year survival of 43 percent (95 percent confidence interval, 22-84 percent). Patients with colonic histology had significantly worse survival than patients with mucinous histology (P = 0.0093). Patients with carcinomatosis had a significantly worse survival than noncarcinomatosis patients (P = 0.0078). Patients who underwent right hemicolectomy had a better prognosis for survival than appendectomy patients, but the difference was not statistically significant.

CONCLUSIONS

Carcinoma of the appendix is very difficult to diagnose preoperatively, and most patients are not identified until disease is advanced. Good prognostic factors include mucinous histology and the absence of carcinomatosis. Right hemicolectomy appears to be a reasonable option, although its superiority to appendectomy alone has not been definitively proven. High frequency of ovarian metastases in women suggests a role for bilateral oophorectomy. In addition, a complete work-up of the patient for a synchronous malignancy, especially in the gastrointestinal tract, should be considered.

Familial ochronosis

We report the case of a 72-year-old female with alkaptonuric ochronosis and symptomatic aortic stenosis requiring aortic valve replacement. She was the seventh of nine children, and four of the nine siblings were diagnosed as having ochronosis. Only one, however presented with aortic stenosis.