Immunogold localisation of endogenous immunoglobulin-G in ultrathin frozen sections of the human placenta

Summary Endogenous immunoglobulin-G was localised in ultrathin frozen sections of human term placenta by use of an indirect immuno electron-histochemical methodology. Immunoreactivity of endogenous IgG to rabbit anti-human immunoglobulin-G antibody was visualised by use of protein-A — colloidal gold complex. Gold marked the syncytiotrophoblast in both coated and uncoated regions of the apical plasmalemma, in vesicles and multivesicular bodies, and in vesicles near the basal plasmalemma. Immunoreactivity was also seen in the interstitial space between the trophoblast and the fetal endothelial layer as well as in various types of vesicles within the endothelial cells. No immunoreactivity was seen in the intercellular clefts of the endothelium. The pattern of localisation observed is consistent with receptor-mediated uptake of immunoglobulin-G into the syncytiotrophoblast of the human placenta followed by release into the interstitial space and then vesciular transport through the endothelium.     

Mucociliary tracheal transport rates in man.

A new method for measuring mucociliary tracheal transport rates (MTTR's) is described. An aqueous aerosol containing albumin microspheres labeled with 99mTc was inhaled in such a manner that it was deposited in local concentrations in the large airways. These boli of microspheres were transported up the trachea and their MTTR's measured using a gamma camera. MTTR's were measured in 42 healthy nonsmoking adults (32 men and 10 women, mean age 28 yr). The mean MTTR's appeared to be log normally distributed with a geometric mean of 3.6 mm/min and a coefficient of variation of 75%. The MTTR's of men and women were similar. Each individual's short-term coefficient of variation was 25%. Twenty-two repeat studies 1 wk to 15 mo apart showed the variation within individuals was less than between individuals. The parasympatholytic drug, atropine (0.6 mg iv) decreased MTTR's for at least 3 h. Inhalation of the sympathomimetic drug, Th1165a increased MTTR's. Chronic and acute smoking did not appreciably change the MTTR'S.     

The influence of 5-halo substituents on the thermal depyrimidination of the glycosidic bond in 2'-deoxyuridines

Following fusion, 2′-deoxynucleosides undergo thermolytic cleavage of the glycosidic bond to yield the corresponding base, furfuryl alcohol, and water. Purine deoxynucleosides are more readily subject to thermal cleavage of the base than are pyrimidine deoxynucleosides, such as 2′-deoxyuridine. However, when the latter deoxynucleoside is substituted by halogens in the 5-position, the glycosidic bond is weakened and loss of halouracil is competitive with ease of depurination. The reduction in strength of the glycosidic bond is linearly related to the corresponding meta Hammett substituent constant.     

The estimation of a bivariate fitness function from two samples taken from a population

Summary The fitness of animals subjected to natural selection can be defined as the probability of surviving selection for a given interval of time, or some convenient multiple of this. If the fitness is related to some measurable variablesX, Y, Z,… then the relationship is expressed mathematically in the fitness functionw(x, y, z,…) and this function can be estimated by comparing the joint distribution ofX, Y, Z,… in samples taken before and after selection. In an earlier paper (Manly, 1975) the problems involved in estimating a fitness function of one variable were discussed. In the present paper various methods for estimating a bivariate fitness function are proposed and compared on some semiartificial sample data. It is concluded that either a generalized version ofO’Donald’s (1968) method of moments or a weighted multiple regression method will be most satisfactory. Alternative methods involving assumptions of normality will need to be used with great care.