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  • 1
    ISSN: 1040-452X
    Keywords: Sperm entry site ; Fertilization ; Actin ; Fertilization cone ; Sperm incorporation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The sperm entry site (SES) of zebrafish (Brachydanio rerio) eggs was studied before and during fertilization by fluorescence, scanning, and transmission electron microscopy. Rhodamine phalloidin (RhPh), used to detect polymerized filamentous actin, was localized to microvilli of the SES and to cytoplasm subjacent to the plasma membrane in the unfertilized egg. The distribution of RhPh staining at the SES correlated with the ultrastructural localization of a submembranous electrondense layer of cortical cytoplasm approximately 500 nm thick and containing 5- to 6-nm filaments. Actin, therefore, was organized at the SES as a tightly knit meshwork of filaments prior to fertilization. Contact between the fertilizing sperm and the filamentous actin network was observed by 15-20 sec postinsemination or just before the onset of fertilization cone formation. Growing fertilization cones of either artificially activated or inseminated eggs exhibited intense RhPh staining and substantial increase in thickness of the actin meshwork. Collectively, TEM and RhPh fluorescence images of inseminated eggs demonstrated that the submembranous actin became rearranged in fertilization cones to form a thickened meshwork around the sperm nucleus during incorporation. The results reported here suggest that activation of the egg triggers a dramatic polymerization of actin beneath the plasma membrane of the fertilization cone. Furthermore, the actin involved in sperm incorporation is sensitive to the action of cytochalasins.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1476-4431
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Canine high-risk surgical patients were identified, and the variables that distinguished between survivors and nonsurvivors were determined. Fifty-two nonsurvivors and 176 survivors were randomly drawn from a population of 615 dogs undergoing general surgical procedures and entering the intensive care unit. Forty-two variables were examined to determine which variables were significantly different between nonsurvivors and survivors. Properative variables that were significantly different were age, hospital days prior to surgery, the number of concurrent diseases, American Society of Anesthesiologists (ASA) status, PCV, TP, platelet count, albumin concentration, alkaline phosphatase activity, bilirubin concentration, and surgery site (laparotomy = highest risk). Age, PCV, TP, platelet count, albumin concentration, alkaline phosphatase activity, and bilirubin concentration were then examined, using stepwise logistic regression for their ability to predict mortality in a separate population of 169 canine patients undergoing laparotomy. Age, TP, and platelet count were identified as predictive variables.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1436-2813
    Keywords: reflux esophagitis ; Barrett's esophagus ; dual muscularis mucosae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chronic esophagitis and the subsequent morphological changes of the esophageal mucosa were histologically studied in esophagectomy specimens from 15 patients with Barrett's esophagus. Basal layer hyperplasia with papillary elongation, intraepithelial eosinophils, and intraepithelial neutrophils were found in the squamous epithelium of all (100%), 7 (46.7%), and 14 (93.3%) of the 15 specimens, respectively. Moreover, a specialized type of Barrett's mucosa was found in the metaplastic columnar lining of all the specimens. The muscularis mucosae appeared intact beneath the squamous epithelium lining the proximal esophagus in 13 specimens (86.7%), while it became thick and “dual” beneath the metaplastic columnar epithelium lining the distal esophagus in 14 specimens (93.3%). This dual muscularis mucosae, as well as the metaplastic columnar epithelium, particularly the specialized type, may be part of the specific histological changes characteristic of Barrett's esophagus.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1435-2451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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