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Biomedical subjects

J Julian

Publications and source records attributed to J Julian.

69 records · Page 4Linked to original sources
PubMed1987

Biological markers during early pregnancy: trophoblastic signals of the peri-implantation period.

The peri-implantation period extends from the time the blastocyst is free in the uterus, through the processes of recognition and attachment, to the beginning of trophoblast differentiation and the interactions between the embryo and the uterine endometrium which initiate establishment of the hemochorial placenta. It is during the peri-implantation period that the embryo and hormonally regulated endometrial cells appear to be most sensitive to factors which introduce risk into the intrauterine environment. There are no markers which can be used practically to assess pregnancy risk during the peri-implantation period of either human or laboratory rodents. Experimental studies, using in vitro laboratory models of differentiating trophoblast cells, have identified peptide hormone markers of pivotal developmental processes. Exposure of trophoblast during the expression of these processes could have severe and far-reaching effects individually and societally. While these trophoblast signals are limited in their utility with respect to health monitoring extrapolation of these findings to human pregnancy, the signals could serve to identify more practical and sensitive markers to assess risk in early gestation. Human chorionic gonadotropin (hCG) has been used extensively as a marker to assess risk during the early stages of pregnancy. Extrapolation of experimental data indicates how hCG could be used more effectively in analyses of possible cause and effect relationships. The limitations of hCG as a marker for risk during the human peri-implantation period are discussed. Peptide hormones which could serve to assess risk during this critical period of extraordinary sensitivity to toxic factors are introduced.

Animals↗
PubMed1986

Intermediate filaments of the midgestation rat trophoblast giant cell.

Trophectoderm (TE) of the rodent blastocyst, the preimplantation precursor of the trophoblast giant cell (TGC), is the first embryonic cell to exhibit intermediate filaments (IF). The two IF proteins of TE (54K and 46K) have been variously described as trophectoderm specific, noncytokeratin, or cytokeratin and have been identified with Endo A and Endo B, IF proteins extracted from extraembryonic endodermal cells. IF proteins of midgestation rat TGC, the postimplantation descendant of TE, were compared to IF proteins of various rat simple epithelial cells by two-dimensional gel electrophoresis, partial proteolytic digest, antibody recognition on electrophoretic transfer, and antibody recognition by indirect immunofluorescence. The two TE IF proteins at 54K and 46K were identified in TGC IF and recognized by anti-Endo A, anti-Endo B, respectively, and anticytokeratins. TGC were found to possess additional cytokeratins at 52K, 45K, 43K, and 40K. The profile of TGC cytokeratins was qualitatively identical to that of various rat simple epithelial cells. The results suggest that (a) TE and TGC IF proteins are cytokeratins, (b) TE and TGC cytokeratins are characteristic of a simple epithelial cell, and (c) the morphologic and functional differentiation of TE to TGC is accompanied by elaboration of the cytokeratin profile.

Animals↗
PubMed1986

Intermediate filament protein as a marker of uterine stromal cell decidualization.

An increase in intermediate filaments has been reported in rat uterine stromal cells undergoing decidualization in vivo and in vitro. In order to identify biochemical correlates of this morphological change, we have identified (two dimensional gel electrophoresis, Western blots, indirect immunofluorescent staining) the constitutive intermediate filament proteins of stromal cells decidualizing in vivo and isolated stroma decidualizing in vitro as vimentin and desmin. Vimentin is common to all uterine stromal cells but increases, proportional to total cell protein, in decidualized stroma. Barely detectable in nondecidualized stroma, desmin, unlike vimentin, increases during decidualization at a rate greater than the increase in total cell protein. Neither the increase in vimentin or desmin is observed in hormonally sensitized, nondecidual stromal cells. Desmin, because it is selectively expressed in decidualizing stroma, could be considered unique enough to serve as a marker of decidual cell differentiation.

Animals↗
PubMed1984

Proteoglycan distribution in rat aortic wall following indwelling catheter injury.

The morphologic response of the aortic wall of the normal fed rat to intimal injury by an indwelling catheter in place for 3 weeks was examined at the time of removal of the catheter and 4, 8, and 26 weeks later. Changes in the concentration of glycosaminoglycan were assayed morphometrically in ruthenium red-stained sections examined by transmission electron microscopy. Two types of ruthenium red-positive granules were identified in the intercellular matrix; large (greater than 20 nm), containing chondroitin sulphate and small (less than 20 nm) containing heparan sulphate. Endothelial denudation and some thrombus seen at the time of removal of the catheter, was associated with a decrease in the concentrations of both types of granules in the subendothelial space compared to normal rats. At later time intervals there was neointimal thickening containing no lipid, and occasional small areas of lipid accumulation. Compared to normal rats there was no significant change in granule concentration in the subendothelial space at any time interval. There was a slight increase in the concentration of large granules of the deep neointima at the time of removal of the catheter and after 4 weeks. In lipid-containing areas there was a highly significant increase in large granule concentrations compared to normal or to intimal thickening without lipid. The observations support the possibility that lipid accumulation is related to an increase in glycosaminoglycan concentration.

Animals↗
PubMed1983

Early changes in venous arterial autografts: a scanning electron microscope study.

The use of autogenous vein as an arterial substitute has been advocated for many years. Methods of harvesting generally cause spasm of the vein and it has been shown that preventing the spasm by applying papaverine improves long-term patency. The present study was undertaken to see if the reported long-term patency of such grafts was associated with improved short-term appearance of the venous endothelium as viewed with the scanning electron microscope. Two groups of dogs were studied; those sacrificed at 3 hours and those at 24 hours after replacing excised segments of the carotid and femoral arteries with cephalic veins. One of the veins was removed in the standard manner allowing spasm followed by distension back to its pre-spasm state; in the other, spasm was prevented by the topical application of papaverine before removal. The study shows that venous endothelial integrity is preserved by the use of papaverine and this improved appearance of the endothelium persists for the first 24 hours after insertion into an arterial milieu. But the study also demonstrated that there was extensive activity of polymorphonuclear leukocytes associated with the endothelium in the early hours after arterialization and that they appeared to have a deleterious effect on the endothelium.

Animals↗
PubMed1982

Intimal hyperplasia in autogenous veins used for arterial replacement.

This study compares the effects on intimal hyperplasia of different methods of manipulating a vein graft before using it as an arterial substitute. Grafts that were denuded of endothelium showed the most intimal hyperplasia, while those that were washed with saline, dilated with saline or crushed did not differ appreciably from each other with respect to the degree of intimal hyperplasia. The hyperplasia was well developed and stabilized at 3 weeks, which coincided with restoration of the endothelial surface. The similarity between the last three methods of graft manipulation suggests that minor endothelial disruption produced at the time of harvesting the vein is equalized after insertion of the vein into the arterial circulation.

Animals↗
PubMedDate not supplied

Neurobehavioral outcomes among farm and nonfarm rural Ecuadorians.

International researchers have urged greater use of simple neurobehavioral batteries in developing country settings where higher levels of exposure and a variety of cultural and demographic factors may both occur. We conducted a cross-sectional survey of 144 farm members and 72 age and education frequency-matched controls from rural Ecuador, using an amplified Neurobehavioral Core Test Battery. Farm members ranged from those with only indirect pesticide contact to applicators regularly applying organophosphate and carbamate insecticides by backpack sprayer. The distributors of scores showed those with less than 4 years of formal education and at the extremes of age (< 16 or > 65 years old) contributed sufficiently to nonnormality that they had to be excluded from subsequent analyses (resultant n = 170). After adjustment for age and education, language-based IQ test scores and farm membership were the most consistent determinants of neurobehavioral outcomes. Visual-spatial tasks were the most sensitive to the effects of farm membership. Gender (women better than men), alcohol problems, and solvent use were also important for some neurobehavioral tests.

Adolescent↗
PubMedDate not supplied

Mucin expression and function in the female reproductive tract.

Reproductive tract epithelia are characterized by the presence of a thick, apical glycocalyx. This glycoprotein coat is drastically reduced in the uterus of many species during the time of embryo implantation. Recent studies indicate that mucin glycoproteins constitute a large proportion of the apical glycocalyx. One of these mucins, Muc-1, has particularly important functions at the luminal surface of the uterus and other female reproductive tract tissues. Muc-1 appears to play a dominant role in maintaining a functionally non-receptive uterine surface with regard to blastocyst attachment. Conversion to a receptive uterine state is brought about by the concerted actions of ovarian steroid hormones that in several species also strongly modulate Muc-1 protein and mRNA expression. Muc-1 also appears to serve a general function in protecting reproductive tract mucosa since Muc-1 null mice are particularly prone to bacterial infection. Collectively, these studies indicate that mucins, including Muc-1, play important barrier roles in reproductive processes and protection from bacterial pathogenesis in the female reproductive tract.

Animals↗
PubMedDate not supplied

Stress fracture of the fifth metatarsal.

Stress fractures of the fifth metatarsal have been reported with increasing frequency, especially in athletes. Prolonged healing time and the risk of refracture following conservative treatment have led to recommendations for operative treatment including bone grafting of these fractures. An axial intramedullary screw, inserted without opening the fracture site, was used in 10 athletes with stress fractures of the fifth metatarsal. Union was obtained in all patients in an average of 7.5 weeks. All patients returned to their sports in an average of 8.5 weeks postoperatively. There were no operative complications or refractures after screw insertion. Complaints of local pain over the screw head and/or the fifth metatarsal head, seen in 7 of the 10 patients, were relieved by local shoe modifications.

Athletic Injuries↗