Internal residue criteria for predicting three-dimensional protein structures

The internal amino acid residues of proteins are almost always non-polar since the hydrophobic effect is very important in stabilizing the three-dimensional structure. This fact suggests several new criteria for judging the correctness of structures predicted from sequence data. The dinucleotide binding domain has been used as a test structure for these criteria. The percentage of ionic residues, mutation data, hydrophobicity, dipole moments, and internal preferences of the residues on the interiors of the known dinucleotide binding folds are consistent with expectations. On the other hand, the values of these parameters for predicted domains in glutamate dehydrogenase (Wootton, J.C. (1974) Nature 252, 542--546) and aldolase (Stellwagen, E. (1976) J. Mol. Biol. 106, 903--911) differ significantly from the expected values indicating that these predictions are not entirely correct. The internal residue criteria can then be used to test modifications of the predictions for a better correlation with the internal residue pattern of the domain.     

Peripheral neuroepithelioma of the kidney

The protective anti-beta abortus monoclonal antibody ISS/32 (Ab1) was used as an immunogen to induce anti-idiotypic antibodies (Ab2) in rabbits. The purpose was to produce and characterize anti-idiotypic antibodies that share conformational similarity with the corresponding bacterial epitope recognized by Ab1. The rabbit anti-IdAb so induced was isolated and affinity-purified. Its specificity for the paratope of Ab1 was determined by evaluating its ability to compete with B. abortus for binding to Ab1 in a competitive ELISA assay. The anti-idiotypic ISS/32 antibodies were able to compete with B. abortus for binding to Ab1 in a dose-dependent manner. Hence, the data indicated that the rabbit anti-Id ISS/32 antibodies reacted with or near the antigen-binding site of Ab1.     

Some properties of phospholipid exchange proteins from rat liver

The hemodynamic response to nitroglycerin administration, to sublingual or oral administration of isosorbide dinitrate, or to a placebo was evaluated and compared in 37 patients with unstable angina pectoris under resting, pain-free conditions. Patients with congestive heart failure were not included in this study. Serial measurements of mean arterial blood pressure (MAP), pulmonary arterial end-diastolic pressure (PAEDP), cardiac index (CI), and heart rate (HR) were obtained for one hour following nitroglycerin administration and for four hours following sublingual or oral administration of isosorbide dinitrate. Echocardiographic end-diastolic volume (EDV) measurements were obtained for the groups receiving isosorbide dinitrate or placebo. There was a significant (P less than 0.05 or less than 0.1) reduction of the MAP (5 to 10 mm Hg) that persisted for more than four hours following both sublingual and oral administration of isosorbide dinitrate. The changes in the PAEDP, HR, and CI following sublingual or oral administration of isosorbide dinitrate were small and not significant. In the group receiving isosorbide dinitrate sublingually, the EDV was reduced by more than 30 ml below the placebo group (P less than 0.1) for up to four hours. The effects of nitroglycerin administration were similar in magnitude but of much shorter duration (three to four hours for sublingual and oral administration of isosorbide dinitrate vs 15 to 30 minutes for nitroglycerin). These data demonstrate that the duration of the hemodynamic effects of sublingually and orally administered isosorbide dinitrate in patients with unstable angina pectoris and normal resting hemodynamics is 8 to 12 times longer than that of nitroglycerin.     

Contraception with the intrauterine pessary Progestasert

A prospective study was carried out from June 1973 to August 1976 in 131 women fitted with a newly developed IUD (Progestasert). The IUD's were removed as planned after 12 months with the exception of 4 cases in which they were retained for up to 17 months. The evaluation of the trial was performed according to the Life Table Analysis and the usual statistical methods. 1496 application months were evaluated. One case each of intrauterine and extrauterine pregnancies were observed. One patient experienced spontaneous expulsion of the IUD. In 9 cases medical reasons led to the removal of Progestasert at an earlier date. Duration, intensity, and interval of menstruation as well as frequency of spotting and dysmenorrhea were recorded. A slight increase in duration and interval of menstruation was seen whereas bleeding intensity was reduced. Increased spotting, especially during the first month after insertion, and a significant reduction of dysmenorrheal complaints were noted after 2 months. In addition to 8 removals due to bleeding disturbances, 6 other patients experienced spotting throughout the entire treatment period. Laboratory tests such as ESR, WBC, hemoglobin, hematocrit and cytological smear determinations were carried out. No pathological alterations of these parameters were found.     

Purification and properties of rabbit reticulocyte protein synthesis initiation factors M2Balpha and M2Bbeta

The active protein components of initiation factor M2B (IF-M2B) have been resolved into two homogeneous factors. These proteins, IF-M2Balpha and IF-M2Bbeta, were purified 300- and 500-fold, respectively, with a yield of about 15% of the original starting activity. The low molecular weight (approximately 17,000) of these two proteins is in contrast with the much greater molecular weights that have been found for other initiation factors. IF-M2Balpha is also unique among the initiation factors in that it contains no tryptophan and is capable of self-association. Both proteins are required for model assays which utilize 40 S and 60 S subunits (poly(U)-directed polyphenylalanine synthesis or AUG-directed methionyl-puromycin synthesis). IF-M2Bbeta has been shown to be required for hemoglobin synthesis, however, the presence of high concentrations of IF-M2Balpha in the 100,000 X g lysate supernatant has precluded the demonstration of an IF-M2Balpha requirement in hemoglobin synthesis.     

Histological features of respiratory epithelium of calves held at differing temperature and humidity

The effect of ambient temperature and humidity on the structure of respiratory epithelium of calves was studied. Four calves of each of three experiments were acclimatized to a nonoperational environmental chamber for six days and then exposed to constant extremes of temperatures and relative humidity of one of 30 degrees C --35%, or 27 degrees C--92%, or 5 degrees C--92% respectively in this chamber for eight days each. Five calves (3 and 2) were similarly acclimatized then exposed to 1 degrees C--40%. Nasal swabs were taken from all animals at regular intervals. Swabs of three animals yielded Mycoplasma spp. and one swab yielded the virus of infectious bovine rhinotracheitis. Detailed histological studies of respiratory epithelium of nose, trachea, major bronchus and terminal bronchioli were conducted at four sites. Goblet cells were least in calves held in hot and dry air; calves held in dry air had the least polymorphonuclear cells and the greatest prevalence of hypochromatic cell layers and vacuolation of epithelial cells. Differences between experiments were evident most for sites of trachea and major bronchus.