Reversal of the human and murine multidrug-resistance phenotype with megestrol acetate

MA is an orally active PG derivative with an excellent safety profile that is used primarily for the treatment of carcinomas of the breast and endometrium. We investigated the potential application of MA as an MDR-reversal agent using cell culture and human tumor xenograft models. The reversing activity of MA in vitro was compared with that of PG and VER in two human MDR cell lines, the colon carcinoma HCT-116/VM46 and the breast carcinoma MCF-7/ADR, and in a murine cell line, J774.2. At concentrations as low as 3 M, MA was capable of partially restoring sensitivity to Act D in the HCT-116/VM46 cells and sensitivity to DOX in the MCF-7/ADR cells. Although less effective than VER, MA was about 2.5 times more potent than PG in reversing MDR at equimolar concentrations. Increased accumulation of DOX in drugresistant cells that were treated simultaneously with MA was observed by flow cytometry. In vivo, using established human colon and breast carcinoma xenografts implanted s.c. in athymic mice, the combined therapy with MA and DOX resulted in enhanced antitumor activity relative to that of DOX alone in the MDR sublines. These results suggest that MA may be a promising clinical MDR-reversing agent.Abbreviations Act D actinomycin D - DOX doxorubicin - PG progesterone - MA megestrol acetate - VER verapamil - VBL vinblastine - MDR multidrug resistance - P-gp P-glycoprotein - MAP medroxyprogesterone acetate - MTD maximum tolerated dose - q4dx3 every 4 days for 3 treatments - TVDD tumor volume-doubling time - IC₅₀ drug concentration producing 50% cell kill in treatéd cultures as compared with controls - PBS phosphate-buffered saline - VM-26 teniposide The part of this work performed at Albert Einstein College of Medicine was supported by USPHS grant CA39821     

Hypothalamic monoaminergic activity in 11-week-old cold-exposed female lean (Fa/Fa) and obese (fa/fa) Zucker rats

We previously reported that serotonergic activity was reduced in the ventromedial hypothalamic nucleus (VMN) of obese vs. lean male Zucker rats. To verify that this reduction was associated with genotype rather than gender, we measured monoamines and their major metabolites in hypothalamic nuclei of 11-week-old female lean (Fa/Fa) and obese (fa/fa) Zucker rats. In addition, since the thermic response to cold is reported to differ between lean and obese rats, some rats were also exposed to 9 degrees or 22 degrees C for 2h to determine if cold exposure altered hypothalamic monoaminergic activity. As in males, levels of 5-hydroxyindoleacetic acid [5-HIAA; major metabolite of serotonin (5-HT)] and the ratio of 5-HIAA/5-HT were lower in the VMN of obese vs. lean females (P = 0.008, 0.001, respectively). 5-HIAA/5-HT was also reduced in the paraventricular (PVN) and suprachiasmatic nuclei (SCN) of the obese compared to the lean females. Cold exposure significantly stimulated brown fat mitochondrial GDP binding in lean but not obese rats. Similarly, levels of norepinephrine, dopamine (DA), 5-HIAA, and 5-HT in the PVN, and 5-HIAA in the SCN increased in cold-exposed lean but not obese rats. In contrast, VMN and preoptic 3,4-dihydroxyphenylacetic acid (DOPAC; major metabolite of DA) increased in the cold-exposed obese but not lean animals. We conclude that: (1) the blunted peripheral response to cold in obese vs. lean Zucker rats is accompanied by altered hypothalamic monoaminergic activity, the physiological role of which needs further evaluation; and 2) depressed VMN serotonergic activity is associated with the obese genotype (fa/fa) rather than gender and as such may contribute to the reduced sympathetic and enhanced parasympathetic outflow from the VMN.     

Problems of comorbidity in mortality after prostatectomy.

OBJECTIVE--In recent studies of patients with benign prostatic hyperplasia (BPH), men undergoing transurethral resection of the prostate (TURP) had higher long-term mortality than men undergoing open prostatectomy. We tested the hypothesis that the higher mortality for patients undergoing TURP could have occurred if these patients were older and sicker at the time of surgery than patients undergoing open prostatectomy. DESIGN AND SETTING--Retrospective cohort study at Yale-New Haven (Conn) Hospital. PATIENTS--Two hundred fifty-two men who underwent TURP or open prostatectomy from 1979 through 1981 for the treatment of BPH. MAIN OUTCOME MEASURES--Five-year mortality adjusted for age and severity of comorbid illness at the time of surgery. RESULTS--The crude 5-year mortality rates were 17.5% (22 of 126 patients) for the TURP group and 13.5% (17 of 126 patients) for the open group. At the time of surgery, however, patients in the TURP group were sicker and older than patients in the open group. As the detail and quality of the assessment of comorbidity increased, the adjusted risk of TURP decreased. Improved classifications of comorbidity in three different forms of statistical analysis did not show an effect of type of prostatectomy on long-term mortality (Mantel-Haenszel relative risk, 1.03; 95% confidence interval, 0.57 to 1.87). CONCLUSIONS--These results suggest that TURP does not increase long-term mortality after surgery for the treatment of BPH. Inadequate accounting for severity of illness may also affect other statistical "adjustments" used in research concerned with patient outcomes.     

Treatment of osseous cleft palate defects: a preliminary evaluation of novel treatment modalities.

OBJECTIVE: To compare the use of autogenous iliac bone graft (ABG) alone with nonresorbable expanded polytetrafluoroethylene Gore-Tex TR membrane (GTM) and with ABG plus resorbable Resolut XT membrane barriers for the secondary closure of alveolar cleft defects. STUDY DESIGN: Fifteen patients aged 9 to 17 years with unilateral cleft palate were included in this study. All patients had primary closure of the soft tissues at infancy. Presurgical orthodontics and scaling preceded the surgery. The patients were randomized to one of three surgical treatment groups: (1) ABG, (2) GTM, or (3) autogenous bone plus resorbable membrane (ABM). Periapical radiographs were taken pretreatment and 2 to 6 years later and were used to measure changes in size (linear and area) of the osseous defect. RESULTS: Significant decreases were observed in mean initial defect width (9.8 to 6.7 mm; p = .0263), mean initial defect height (20.7 to 15.1 mm), and overall mean defect size (223.6 to 143.9 mm2). Greater improvement in mean defect width was observed for the ABM group (6.42 mm) compared with the ABG (1.22 mm) and GTM (1.38 mm) groups. The reduction in overall mean defect size was significantly greater in the ABM group (177 mm2) compared with the GTM (20.51 mm2) and ABG (41.69 mm2) groups. CONCLUSION: Guided bone regeneration was found potentially useful for the treatment of osseous cleft palate defects. The combined approach yielded significantly greater defect fill. If further substantiated in larger independent studies, the adjunctive use of barrier membranes could improve the management of secondary closure of cleft palate defects.     

Percutaneous spermatic vein occlusion: evaluation of sclerosing agents in experimental animals

The 5%-20% rate of recurrence of testicular varicoceles after embolotherapy has been a persistent clinical problem. Three sclerosing agents--sodium tetradecyl sulfate 3%, absolute ethanol, and 100 degrees C contrast material--were evaluated in canine spermatic veins for degree and durability of venous occlusion. Pathologic examination for perivenous, pulmonary, and neural changes was performed. Both sodium tetradecyl sulfate and absolute ethanol were effective sclerosants, but sodium tetradecyl sulfate was technically easier to use. The use of a sclerosant in conjunction with balloons or coils is the safest, most effective technique for occluding variococeles and minimizing postembolotherapy recurrences.     

In vitro inhibition of estrogen sulfoconjugation by some 2- and 4-substituted estra-1,3,5(10)-trien-17 beta-ols1a

Hormone-responsive rat and human mammary tumor, unlike normal epithelium, actively sulfoconjugates estrogens. The title compounds (9-11) were synthesized in search of specific inhibitors of estrogen sulfotransferase as a possible means of developing effective chemotherapeutic agents for treatment of hormone-dependent human mammary cancer. 4-Nitroestrone 3-triflate (7a) was converted to the corresponding estradiol derivative (8a) in 93% yield by reduction with NaBH4 under phase-transfer conditions. Catalytic reduction (10% Pd/C) of the latter gave 4-aminoestra-1,3,5(10)-trien-17 beta-ol (9a) in 77% yield. These same reactions were applied consecutively to 4-nitroestrone 3-nonaflate (7b) to give 9a in 56% overall yield. The amino steroid (9a) was converted to 4-fluoroestra-1,3,5(10)-trien-17 beta-ol (10a) via a Balz-Schiemann reaction, in 17% overall yield. Successive NaBH4 and (10% Pd/C) catalytic reductions of 4-fluoroestrone 3-O-(1-phenyl-1H-tetrazol-5-yl) ether (2b) provided a less satisfactory route to 10a. MCPBA oxidation of 9a gave 4-nitroestra-1,3,5(10)-trien-17 beta-ol (11a) in 56% yield. The same series of reactions were applied to 2-nitroestrone 3-triflate (7c) to give 2-amino- (9b), 2-fluoro- (10b), and 2-nitro- (11b) estra-1,3,5(10)-trien-17-ols in comparable yields. Substitution in the A ring results in improved inhibition of porcine endometrial sulfotransferase sulfoconjugation of estradiol relative to estra-1,3,5(10)-trien-17 beta-ol (4a). Moreover, electronegative substitution at C-4 of 4a is more effective than at C-2. In particular, the Ki (2.43 +/- 0.16 microM) of 11a is sixfold smaller than that of the unsubstituted steroid (4a).     

Chemical Nature of the Interaction between Macrophage Fusion Factor and Macrophage Membranes

Giant-cell formation induced by macrophage fusion factor (MFF) was not altered after pretreatment of macrophages with trypsin, chymotrypsin, pronase, neuraminidase, phospholipase C, or phospholipase D. Pretreatment of macrophages with either alpha-mannosidase or alpha-glucosidase completely inhibited giant-cell development, without altering macrophage viability. No alteration of giant-cell formation was observed when 0.1 M of L-fucose, N-acetyl-glucosamine, D-arabinose, D-xylose, melibiose, D-glucose, D-galactose, alpha-lactose, sucrose, D-fructose, or maltose was present during incubation of macrophages with MFF. Giant-cell formation was abolished when 0.1 M alpha-D-mannose was present during macrophage incubation with MFF. These results suggest that the protein moiety of MFF recognizes a specific receptor site on the macrophage membrane, one that is different from those described for other lymphokines and contains alpha-mannose.     

Manometrically guided colon insufflation during double-contrast barium enemas

The double-contrast enema's potential for high accuracy depends in part on consistently good inflation of the colon. However, optimal inflation is often not obtained because of deflation during filming, underinflation because of fear of perforating the colon, or patient discomfort. To help meet the dual requirements of ensuring consistently good bowel inflation while avoiding over-inflation, we have designed a modified insufflator which incorporates a manometer and allows accurate readings of intraluminal large-bowel pressures during or following insufflation. In more than 3000 examinations using this method we have experienced no complications.