The origin of the nascent blastocoele in preimplantation mouse embryos ultrastructural cytochemistry and effect of chloroquine

Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.     

Application of enzyme-linked immunosorbent assay for mass examination of strongyloidiasis in okinawa, Japan

The enzyme-linked immunosorbent assay was tested to evaluate whether it could be applicable in screening for mass examination of strongyloidiasis. A total of 2906 inhabitants in three areas (858 in Gushikawa Village, 849 in Nakazato Village and 1199 in Sashiki Town) were screened by the enzymatic assay and approximately 11–30% (11.8% in Gushikawa, 17.0% in Nakazato and 27.7% in Sashiki) were considered to be antibody positive. In the parasitological follow-up examinations of those who were antibody positive, actual infection was found in more than half (51%) the subjects. The overall infection rates estimated from the results reached 5.8% in Gushikawa, 9.1% in Nakazato and 14.0% in Sashiki (mean = 10.4%). The infection rates were significantly higher than those in previous surveys conducted in the same areas. The ELISA technique was found to be useful for strongyloidiasis screening and for seroepidemiological purposes in Okinawa.     

Effects of spleen cells and serum on transfer of immunity to Strongyloides venezuelensis infection in hypothymic (nude) mice

The course of Strongyloides venezuelensis infection in congenitally hypothymic (nu/nu) mice and their heterozygous thymus-bearing littermates (nu/+) was followed. Unlike the infected nu/+ mice, the nu/nu mice were unable to expel the worms until the end of the observation period (98 days post-infection). In addition, about three times as many eggs were counted at the peak level of infection in faeces of the infected nu/nu mice in comparison with the nu/+ mice. No acquired resistance to rechallenge was observed among the nu/nu mice. Auto-reinfection within the infected nu/nu mice could not be supposed in the present study. The worm expulsion mechanism was generated by nu/nu mice which had been given syngeneic spleen cells from intact +/+ mice. The expulsion of adult worms, as well as the protection against migrating larvae, occurred anamnestically when spleen cells from immune +/+ mice were transferred. The serum transfer, however, only caused a retardation of larval migration. The results support the hypothesis that direct worm immunity and worm expulsion are a T cell-dependent phenomenon.     

A laboratory investigation of temperature and salinity tolerances of juvenile Metapenaeus bennettae Racek and Dall (Crustacea: Penaeidae)

Temperature and salinity tolerances of juvenile Metapenaeus bennetlae Racek and Dall were estimated by abrupt exposure to critically high or low levels of each factor following acclimation to 12 combinations of temperature (17, 22, 27 and 32°C) with salinity (5, 20 and 35‰.). No significant differences were found between tolerances of males and females. Acclimation temperature influenced both temperature and salinity tolerances, while acclimation salinity affected only the salinity tolerance. Irrespective of temperature and salinity acclimation levels, juvenile M. bennettae were able to tolerate temperatures from 8.1 to 32.9°C and salinities from 1.0 to 62.0‰ These findings are discussed in relation to similar published studies.     

Preparation from keratin sulfate of substrates for the measurement of 2-acetamido-2-deoxy-D-glucose 6-sulfate sulfatase and (1 goes to 3)-N-acetyl-beta-D-glucosaminidase

An extract of bacterial cells Pseudomonas sp. IFO-13309 grown on medium containing 0.1% bovine cornea keratan sulfate of low sulfate content degraded exhaustively bovine cornea keratan sulfate to give 2-acetamido-2-deoxy-beta-D-gluco-pyranosyl 6-sulfate-(1 goes to 3)-D-galactose, isolated by gel filtration on Sephadex G-25 and purified by preparative paper chromatography. This was reduced with sodium borotritide to give 2-acetamido-2-deoxy-beta-D-glucopyranosyl 6-sulfate-(1 goes to 3)-D-[1-3H]galactitol, purified by gel filtration on Sephadex G-15, which was an excellent substrate for the measurement of 2-acetamido-2-deoxy-D-glucose 6-sulfate sulfatase. The reduced, radioactive monosulfated disaccharide was desulfated with methanolic 70mM hydrogen chloride and purified by gel filtration on Sephadex G-15 to give O-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-(1 goes to 3)-D-[1-3H]galactitol, which allowed the measurement of (1 goes to 3)-N-acetyl-beta-D-glucosaminidase. This enzyme may participate in the normal degradation of keratan sulfate.     

Effect of triiodothyronine on blood lipids in obesity.

Different blood lipid components were evaluated in obese and normal Egyptians. In obese, plasma levels of total lipoproteins, beta-lipoprotein, total cholesterol, triglycerides, and non-esterified fatty acids were found to be significantly elevated. The plasma levels of esterified cholesterol and phospholipids were found to be significantly reduced. Tertroxine caused a drop of the plasma level of total lipoproteins, beta lipoproteins and total cholesterol and rise of plasma level of non-esterified fatty acids.