A controlled trial of leuprolide with and without flutamide in prostatic carcinoma

To test the hypothesis that maximal androgen blockade improves the effectiveness of the treatment of prostatic cancer, we conducted a randomized, double-blind trial in patients with disseminated, previously untreated prostate cancer (stage D2). All 603 men received leuprolide, an analogue of gonadotropin-releasing hormone that inhibits the release of gonadotropins, in combination with either placebo or flutamide, a nonsteroidal antiandrogen that inhibits the binding of androgens to the cell nucleus. As compared with the 300 patients receiving leuprolide and placebo, the 303 patients randomly assigned to receive leuprolide and flutamide had a longer progression-free survival (16.5 vs. 13.9 months; P = 0.039) and an increase in the median length of survival (35.6 vs. 28.3 months; P = 0.035). The differences between the treatments were particularly evident for men with minimal disease and good performance status; however, further studies should be conducted in this subgroup. Symptomatic improvement was greatest during the first 12 weeks of the combined androgen blockade, when leuprolide alone often produces a painful flare in the disease. We conclude that in patients with advanced prostate cancer, treatment with leuprolide and flutamide is superior to treatment with leuprolide alone.     

Brief intense exercise followed by passive recovery modifies the pattern of fuel use in humans during subsequent sustained intermittent exercise

The role of work period duration as the principal factor influencing carbohydrate metabolism during intermittent exercise has been investigated. Fuel oxidation rates and muscle glycogen and free carnitine content were compared between two protocols of sustained intermittent intense exercise with identical treadmill speed and total work duration. In the first experiment subjects (n=6) completed 40 min of intermittent treadmill running involving a work : recovery cycle of 6 : 9 s or 24 : 36 s on separate days. With 24 : 36 s exercise a higher rate of carbohydrate oxidation approached significance (P=0.057), whilst fat oxidation rate was lower (P ≤ 0.01) and plasma lactate concentration higher (P ≤ 0.01). Muscle glycogen was lower post‐exercise with 24 : 36 s (P ≤ 0.05). Muscle free carnitine decreased (P ≤ 0.05), but there was no difference between protocols. In the second experiment a separate group of subjects (n=5) repeated the intermittent exercise protocols with the addition of a 10‐min bout of intense exercise, followed by 43 ± 5 min passive recovery, prior to sustained (40 min) intermittent exercise. For this experiment the difference in fuel use observed previously between 6 : 9 s and 24 : 36 s was abolished. Carbohydrate and fat oxidation, plasma lactate and muscle glycogen levels were similar in 6 : 9 s and 24 : 36 s. When compared with the first experiment, this result was because of reduced carbohydrate oxidation in 24 : 36 s (P ≤ 0.05). There was no difference, and no change, in muscle free carnitine between protocols. A 10‐min bout of intense exercise, followed by 43 ± 5 min of passive recovery, substantially modifies fuel use during subsequent intermittent intense exercise.     

Treatment of tuberculosis in patients with advanced human immunodeficiency virus infection

BACKGROUND AND METHODS. Infection with the human immunodeficiency virus (HIV) increases the risk of tuberculosis and may interfere with the effectiveness of antituberculosis chemotherapy. To examine the outcomes in patients with both diagnoses, we conducted a retrospective study of all 132 patients listed in both the acquired immunodeficiency syndrome (AIDS) and tuberculosis case registries in San Francisco from 1981 through 1988. RESULTS. At the time of the diagnosis of tuberculosis, 78 patients (59 percent) did not yet have a diagnosis of AIDS, 18 patients (14 percent) were given a concomitant diagnosis of AIDS (as determined by the presence of an AIDS-defining disease other than tuberculosis), and the remaining 36 patients (27 percent) already had AIDS. The manifestations of tuberculosis were entirely pulmonary in 50 patients (38 percent), entirely extrapulmonary in 40 patients (30 percent), and both pulmonary and extrapulmonary in 42 patients (32 percent). The treatment regimens were as follows: isoniazid and rifampin supplemented by ethambutol for the first two months, 52 patients; isoniazid and rifampin supplemented by pyrazinamide and ethambutol for the first two months, 39 patients; isoniazid and rifampin, 13 patients; isoniazid and rifampin supplemented by pyrazinamide for the first two months, 4 patients; and other drug regimens, 17 patients. The intended duration of treatment for patients whose regimen included pyrazinamide was six months, and for patients who did not receive pyrazinamide, nine months. Seven patients received no treatment because tuberculosis was first diagnosed after death. Sputum samples became clear of acid-fast organisms after a median of 10 weeks of therapy. Abnormalities on all chest radiographs taken after three months of treatment were stable or improved except for those of patients who had new nontuberculous infections. The only treatment failure occurred in a man infected with multiple drug-resistant organisms who did not comply with therapy. Adverse drug reactions occurred in 23 patients (18 percent). For all 125 treated patients, median survival was 16 months from the diagnosis of tuberculosis. Tuberculosis was a major contributor to death in 5 of the 7 untreated patients and 8 of the 125 treated patients. Three of 58 patients who completed therapy had a relapse (5 percent); compliance was poor in all 3. CONCLUSIONS. Tuberculosis causes substantial mortality in patients with advanced HIV infection. In patients who comply with the regimen, conventional therapy results in rapid sterilization of sputum, radiographic improvement, and low rates of relapse.     

Effects of incentive items on participation in a randomized chemoprevention trial

Behavioral research has an important role in increasing and maintaining participation in disease prevention trials, both in interventions and in follow-up visits. We conducted a randomized experiment among participants in the lung cancer chemoprevention trial, CARET (Carotene and Retinol Efficacy Trial) to test the effects of providing two incentives on retention. The items used for this study were a Certificate of Appreciation and one of two lapel pins, provided in a 2 2 design. Providing incentives, whether alone or in combination, had no statistically significant effect on retention by the two-year follow-up point. The successful implementation of this randomized incentive study has two implications for future research: (1) study of behavioral interventions and issues is feasible in the context of large controlled trials of disease end-points; and (2) such study is necessary to determine whether selected incentives can increase retention.     

polyhomeotic: a gene required for the embryonic development of axon pathways in the central nervous system of Drosophila

Hypomorphic alleles of the locus polyhomeotic (ph) produce multiple, homeotic-like transformations in adult flies that mimic dominant mutations in the Antennapedia and Bithorax complexes. Analysis of null alleles of ph has revealed a complex, embryonically lethal phenotype that includes cell death of the ventral epidermis and abnormalities in the patterns of expression of homeotic and segmentation genes. There is also a dramatic alteration in the pattern of axon pathways in the central nervous system, such that the wild-type array of segmentally repeated commissures and connectives is replaced by bundles of axons confined to the hemiganglia of origin. It is possible that this axonal phenotype is the result of loss of neuronal identity caused by abnormal homeotic and segmentation gene expression.     

Glycoproteins present in human follicular fluid that inhibit the zona- binding capacity of spermatozoa

Previous studies have suggested that human follicular fluid contains factors that reduce the zona-binding capacity of spermatozoa. The present study provides further evidence of the existence of such factors. Using the hemizona binding assay (HZA), we have shown that the inhibitory effect of human follicular fluid on the zona-binding capacity of spermatozoa is concentration-dependent, an inhibitory effect being detected when the concentration of human follicular fluid was > or = 10%. A 1% concentration of human follicular fluid did not possess this inhibitory activity. Heating human follicular fluid at 56 degrees C for 30 min did not affect its inhibitory properties; treatment with proteinase-K abolished such inhibition. Human follicular fluid was fractionated sequentially by concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography and Superose-12 gel filtration. The zona binding inhibitory activity resided in the fraction which bound to the lectin and Mono Q column and contained molecules with native molecular weights of 32 and 192 kDa. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein remained as a single molecular species under denaturing conditions. We conclude that two glycoproteins were responsible for the zona binding inhibitory activity of human follicular fluid. The physiological role of these factors remains unclear.      

Biochemical responses during recovery from maximal and submaximal swimming exercise

Summary We set out to demonstrate whether changes in plasma volume, haematocrit and some important blood constituents occurred after swimming 100 m and 800 m, as well as monitoring the duration of these changes. We measured exercise-induced changes in concentration of plasma constituents in eight subjects, and determined the expected effects of haemoconcentration on these constituents. We also investigated the different biochemical responses occurring after maximal exercise (100 m), as compared to submaximal exercise (800 m). The haematocrit increased significantly after the 100 m swim and to a lesser extent after the 800-m swim, returning to basal levels within 30 min. The plasma volume decreased by 16% on completion of the 100 m and by 8% on completion of the 800 m. The blood lactate concentration increased 15-fold and 10-fold after the 100-m and 800-m swims respectively. The plasma potassium concentration increased significantly immediately on completion of the 100-m swim, then decreased significantly at 2 1/2 and 5 min post-exercise, returning to near-basal values at 30 min. The potassium concentration measured after the 800-m event did not differ significantly from basal levels, however the measured concentrations were significantly lower than the concentrations expected on the basis of haemoconcentration. The plasma sodium concentrations measured after both 100-m and 800-m swims were significantly increased. However, calculations correcting for haemoconcentration showed significant losses in toal circulating sodium. Our study demonstrates marked changes in plasma volume and certain blood constituents after maximal intensity swimming, and less marked changes after submaximal exercise. We also demonstrated the importance of taking the effects of haemoconcentration into account when evaluating changes in concentration of plasma constituents.