Electron probe microanalysis of elemental composition of mouse cardiac myocytes during post-natal maturation

Elemental concentrations in the cytoplasm and nucleus of t tests post-natal mouse myocytes were measured at 2, 4, 8, 16, 32 days and in adults using electron probe X-ray microanalysis. Using an analysis of variance test, significant age dependent changes were found in intracellular potassium, sulfur, phosphorus, and chlorine concentrations (mg/kg dry weight), while sodium and magnesium concentrations did not show significant changes. The application of t tests following linear regression analyses (age versus concentration for each element) did, however, give a significant slope for cytoplasmic sodium, potassium, sulfur, and phosphorus values. The findings correspond closely with an emission spectroscopy-titrimetric study of whole heart ventricle of the same developmental period (Hazelwood and Nichols, '70).     

Electron microscope analysis of the transplacental effect of azathioprine on the pancreas of albino mouse embryos

An electron microscopic investigation has been performed to study the transplantation effect of azathioprine (imuran) on the pancreas of the white mouse embryos. Azathioprine is administered to female mice at various time of pregnancy. The pancreas of 19-20-day-old embryos is studied. Azathioprine produces an unfavourable effect on the embryonal pancreacytes; it is manifested as some disorders in structure of organelles, appearance of the intracellular degeneration foci, disturbed maturation of the zymogen granules, premature secretion of zymogen into the acinar lumen during the prenatal period. In the insulocytes similar changes are observed in their organelles, as well as appearance of unusual in size alpha- and beta-granules. As a whole, the epithelium of the endocrine part of the gland is evidently more resistive to the preparation.     

Electron probe x-ray analysis of siderosomes in the rabbit haemarthrotic synovial membrane.

Electron probe x-ray analysis of siderosomes produced in the rabbit synovial membrane by repeated injections of autologous blood revealed two kinds of siderosomes; (1) those containing a small amount of phosphorus and, (2) those in which no phosphorus was detectable. On the basis of these findings and past studies it is concluded that haemosiderin is an inorganic compound of iron, probably a hydrated ferric oxide and that a variable amount of organic material (proteins, lipids, phospholipids, etc.,) probably occurs in company with the haemosiderin in the siderosome, but these variable components which decrease in amount with the passage of time cannot be considered as an integral part of haemosiderin.     

Electron microprobe analysis of elemental distribution in excavated human femurs

Elemental distributions have been determined for femur cross sections of eight individuals from the Gibson and Ledders Woodland sites. The analyses were obtained by x-ray fluorescence with a scanning electron microscope. Movement of an element from soil to bone should give rise to inhomogeneous distributions within the bone. We found that the distributions of zinc, strontium, and lead are homogeneous throughout the femur. In contrast, iron, aluminum, potassium, and manganese show clear buildup along the outer surface of the femur and sometimes along the inner (endosteal) surface, as the result of postmortem enrichment. The buildup penetrates 10-400 micron into the femur. The major elements calcium and sodium show homogeneous distributions, but considerable material could be lost by leaching (10-15%) without causing a palpable effect on the electron maps. Magnesium shows buildup on the outer edge of some samples. These results suggest that diagenetic contamination may exclude Fe, Al, K, Mn, and probably Mg from use as indicators of ancient data. The homogeneous distributions of Zn, Sr, and Pb suggest that these elements are not altered appreciably and may serve as useful dietary indicators.     

Uterine and oviducal protein secretion during early pregnancy in the mouse

Changes in the protein composition of the embryo's environment during early development were studied by analysis of proteins synthesized and secreted by oviducal and uterine explants on Days 1-6 of pregnancy. Although secretions from ampullar and isthmic oviduct and uterus contained many proteins in common, each area also produced its own characteristic proteins. In the uterus, changes in the secretion pattern were found during the peri-implantation period, including both increases and decreases in particular proteins which appear to be dependent on the presence of embryos. Embryo-induced effects on uterine secretion began between 09:00 h of Day 4 and 09:00 h of Day 5. Oviducal secretions exhibited many of the embryo-dependent proteins found in the uterus, but the expression of these proteins did not appear to be influenced by the presence of embryos on Day 1 or Day 3. The characteristic pattern of secreted protein expression by each portion of the reproductive tract may reflect the specialization of each area for certain developmental events.     

Electron probe analysis of calcium transport by small intestine

Calcium transport in small intestine of rat and chick has been studied at the cellular level using the electron probe X-ray microanalyzer. Tissues were examined directly after removal as well as after incubation in a calcium solution. In both preparations, discrete calcium localizations were found associated with intracellular and extracellular goblet cell mucus. The in vitro preparations showed calcium in transit across the absorptive epithelium in discrete localizations. Although the primary path of transport was along lateral cell borders, some localizations were found in the cytoplasm in a supranuclear position. The effect of vitamin D depletion and repletion was to decrease and increase, respectively, the number of calcium localizations in transit across the epithelium. These results suggest that calcium is transported while in a sequestered form and indicate that goblet cell mucus plays a role in this transport process.     

Electron probe microanalysis of potassium and phosphorus in mouse oocytes and zygotes

Intracellular concentrations of potassium and phosphorus were determined by Electron Probe Microanalysis in mouse mature oocytes and zygotes. The oocytes were characterized by insignificant variations in the concentrations of these elements in the cytoplasm: 60 +/- 4 and 103 +/- 6 mM, respectively. In zygotes, on the contrary, significant variations were observed: 64 +/- 16 and 84 +/- 14 mM, respectively. Changes in the potassium homeostasis during the first cell cycle have been discussed.     

Electron microscopic analysis of replicating DNA of sea urchin embryos

DNA was extracted from Paracentrotus lividus embryos at the third S phase after fertilization and analyzed with the electron microscope. The most relevant structures observed in this actively replicating DNA are clusters of short, closely spaced microbubbles (about 0.1 μm long on the average), partially or entirely single-stranded molecules and few linear forks. Unexpectedly, no long eye forms were observed. The analysis of DNA purified from gastrulae and from adult somatic tissues has revealed the same structures, although at a low frequency. A quantitative analysis has been carried out to determine the size distribution and spacing of microbubbles. A number of control experiments have been performed to characterize these structures better. Various possibilities are discussed to account for the presence of the observed forms and the absence of larger eyes.     

Co-culture of early cattle embryos to the blastocyst stage with oviducal tissue or in conditioned medium

In Exp. 1, 5-8-cell embryos from superovulated cattle were co-cultured with oviducal tissue suspended in Ham's F10 + 10% fetal calf serum (F10FCS) or in F10FCS alone. After 4 days, the proportion of embryos developing into compact morulae or blastocysts was greater (P less than 0.005) in co-culture (38/82; 46%) than in F10FCS (1/27; 4%). In Exp. 2, a solution of collagenase, trypsin, DNAse and EDTA was used to disperse oviducal tissue, which was then cultured in TCM199 + 10% fetal calf serum (M199FCS) to obtain monolayers. Embryos (1-8 cells) were then co-cultured with monolayers or in M199FCS alone. The proportion of embryos developing into compact morulae and blastocysts after 4-5 days was higher (P less than 0.005) in co-culture (15/34; 43%) than in M199FCS (1/37; 3%); mean numbers of cells/embryo were also higher (P less than 0.001) (27.70; range 2-82 in co-culture; 8.83; range 2-18 in M199FCS). In Exp. 3, embryos obtained from in-vitro maturation and fertilization were used to compare development between co-culture and medium conditioned by oviducal tissue. Initial cleavage rate (no. embryos greater than 1 cell/total) was 76% (611/807) and did not differ among treatments. After 5 days, the proportion cleaving to greater than 16 cells was higher (P less than 0.005) in co-culture (71/203; 35%) and conditioned medium (48/205; 23%) compared to M199FCS (14/203; 7%). Similarly, the proportion developing into compact morulae and blastocysts was greater (P less than 0.005) in co-culture (44/203; 22%) and conditioned medium (46/205; 22%) than in M199FCS (7/203; 3%).(ABSTRACT TRUNCATED AT 250 WORDS)