The management of midtrimester abortion failures by vaginal evacuation

Ionized calcium was determined in vitro in human serum in relation to increased concentrations (0.32 to 10 mM) of free fatty acids. Serum iCa levels varied inversely and linearly with increasing FFA concentrations. It is suggested that the formation of Ca-FFA complexes at clinically attainable levels of FFA decreases iCa and that elevated serum FFA levels may be a factor in the development of hypocalcemia.     

Energy metabolism in weight-stable postobese individuals

A low metabolic rate for a given body size and body composition and a low ratio of fat to carbohydrate oxidation predict body weight gain. Such metabolic traits could also explain, in part, the propensity of previously obese (postobese) individuals to regain weight after dieting. We studied 11 postobese volunteers (4 males, 7 females; aged 43 +/- 13 y, weighing 80.6 +/- 10.2 kg, with 30 +/- 7% body fat; x +/- SD) who lost 57 +/- 38 kg (23-139 kg) over 14 +/- 12 mo (6-48 mo) on various diet programs and had maintained this weight loss for > or = 2 mo (2-72 mo; 21 +/- 27 mo). After > or = 2 d of a weight-maintenance diet on a metabolic ward, 24-h energy expenditure and ratio of fat to carbohydrate oxidation were measured in a respiratory chamber. Compared with a control group (n = 110) with similar physical characteristics (aged 43 +/- 14 y, weighing 79.5 +/- 11.4 kg, with 30 +/- 12% body fat), [sequence: see text] postobese individuals had similar energy expenditures adjusted for fat-free mass, fat mass, age, and sex, but significantly higher respiratory quotients over 24 h (0.883 +/- 0.026 compared with 0.863 +/- 0.024, P < 0.01) and during sleep, 10 h after the last meal (0.894 +/- 0.063 compared with 0.845 +/- 0.055). These results suggest that postobese individuals have low rates of fat oxidation that may explain their propensity to regain weight.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mapping DNAase l-susceptible sites in nucleosomes labeled at the 5' ends

We have used lambda-32P-ATP and polynucleotide kinase to label stoichiometrically the 5' ends of DNA in intact isolated HeLa cell nucleosomes. DNA is not nicked or degraded during the modification reaction. We have used these modified nucleosomes to study both the distribution and the relative availability of sites within the nucleosome which are susceptible to digestion by DNAase l. The results show that the nucleosome contains a potential cleavage site every 10 nucleotides, with the exception of the site 80 nucleotides from the 5' end. Favored cleavage sites are located 20, 40, 50, 100, 120, and 130 nucleotides from the 5' end; sites 30 and 110 nucleotides from the 5' end are strongly disfavored, while the potential site 80 nucleotides from the 5' end is virtually never cleaved. These findings provide constraints for models of histone-DNA interactions within the chromatin subunit.     

Histone composition of nucleosomes isolated from cultured Chinese hamster cells

Nuclei isolated from cultured Chinese hamster cells were treated with micrococcal nuclease and lysed, and the resulting chromatin subunit classes (nucleosomes) were purified by sedimentation and resedimentation through isokinetic sucrose gradients. Nucleosomes isolated from [3H]thymidine-labeled cells were analyzed for DNA size using both polyacrylamide gel and electron microscopic techniques. Nucleosomes isolated from [14C]lysine-labeled cells were analyzed for protein content using a sodium dodecyl sulfate-polyacrylamide gel system. The results from monitoring the [14c]lysine in each protein indicate that, in the nucleosome classes (monomer through tetramer), the molar ratios of histones H2A, H2B, H3, and H4 are equivalent. Furthermore, in each population of the nucleosome classes monomer through tetramer, it was possible to demonstrate that this histone unit (H2A + H2B + H3 + H4) is present, on the average, in the amount of two for monomers, four for dimers, six for trimers, and eight for tetramers. This is direct experimental confirmation of the prediction of R.D. Kornberg [(1974) Science 184, 868] concerning the substructure of chromatin.     

Interleukin-12 enhances in vivo parasiticidal effect of benznidazole during acute experimental infection with a naturally drug-resistant strain of Trypanosoma cruzi

The roles of gamma interferon (IFN-gamma) and interleukin-12 (IL-12) in mediating and/or enhancing the in vivo trypanosomicidal activity of the nitroheterocyclic derivative benznidazole (Bz) were evaluated during early stages of experimental Chagas' disease. Our results show that treatment of Trypanosoma cruzi-infected mice with anti-cytokine monoclonal antibodies (MAbs) had no apparent effect when the optimal dose of Bz (100 mg/kg of body weight) was used. In contrast, treatment with anti-IL-12 or anti-IFN-gamma MAbs enhanced the parasitemia and accelerated the mortality of mice treated with a suboptimal dose of Bz (25 mg/kg). Simultaneous treatment with a suboptimal dose of Bz and recombinant IL-12 (rIL-12) enhanced the efficacy of drug treatment in terms of parasitemia and mouse survival. Interestingly, we found that drug-resistant T. cruzi strains were found to be poor inducers of IL-12 both in vitro and in vivo compared to strains of T. cruzi which are susceptible or partially resistant to Bz treatment. These results suggest that early activation of the cellular compartment of the immune system by IL-12 may favor in vivo Bz activity against T. cruzi. In order to test this hypothesis mice infected with the drug-resistant Colombiana strain of T. cruzi were treated with 100 mg of Bz per kg plus different concentrations of rIL-12. By using the results of PCR and serological and parasitological methods as the criteria of a cure, our results indicate that a higher percentage of mice treated with Bz combined with rIL-12 than mice treated with Bz alone are cured.