Epithelial cells isolated from the caput epididymidis of adult rats were placed in primary culture and examined daily for ten days for changes in external anatomy, reorganization of cytoskeletal components, maintenance of characteristic cytoplasmic features, and response to media formulated to minimize nonepithelial cell proliferation. Significant cell attachment to the substrate began after the first 24 hours of culture. After attachment, the cells underwent a progressive flattening and became closely applied to the substrate. This was accompanied by a redistribution of microvilli on the cell surface and a reorganization of cytoskeletal elements within the cell. After flattening, the cultured cells displayed an extensive array of 10-nm filaments which were associated with the desmosomes attaching adjacent cells. Immunofluorescence studies demonstrated that these were keratin-containing intermediate filaments and 2-D gel electrophoresis of intact cells and cell cytoskeletons revealed that a family of "keratin-like" polypeptides were major components of the cells. Epithelial cell attachment, morphology, and maintenance in the primary culture were unaffected by D-valine, cytosine arabinoside, or both; however, these agents, either individually or in combination, reduced significantly the number of cells incorporating 3H-thymidine. These data show that isolated epithelial cells retain some differentiated structural features that characterize the intact cell and that enriched cultures of epithelial cells can be maintained under conditions where fibroblast proliferation is inhibited.

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PubMedDate not supplied

Parasite-directed endocytosis.

Following the attachment of gonococci to human fallopian tube mucosa in organ culture, the gonococci are endocytosed by specialized low columnar epithelial cells, are transported to the base of the epithelial cells, and are subsequently exocytosed into the subepithelial tissues. This transepithelial transport process by which "invasion" of the host occurs appears to be dependent on microbial factors is designated parasite-directed endocytosis to distinguish it from host-directed endocytosis by cells such as macrophages that eventually degrade the parasites. "Invasion" of the host by a number of human pathogens--bacteria (e.g., Neisseria meningitidis, Haemophilus influenzae, and Listeria monocytogenes), viruses, or protozoa--appears to be accomplished by parasite-directed endocytosis.

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PubMedDate not supplied

Mechanisms of mucosal invasion by pathogenic Neisseria.

Neisseria gonorrhoeae are transported across the mucosa of human fallopian tubes in organ culture by mucosal cells. The steps in this process are (1) attachment of gonococci to microvilli of nonciliated cells, (2) phagocytosis of gonococci by these cells, (3) transport of phagocytic vacuoles containing gonococci to the base of the cell, and (4) exocytosis of gonococci with phagocytic vacuoles into the subepithelial tissues. In vivo gonococci in the subepithelial tissues may cause extensive local disease (e.g., salpingitis) or invade blood vessels to cause disseminated disease. Preliminary studies of human nasopharyngeal tissue in organ culture infected with Neisseria meningitidis indicate that meningococci attach to microvilli of nonciliated cells and are phagocytized by these cells. They subsequently appear in subepithelial tissues, but the route they take is not yet certain. These observations suggest that the mechanisms of attachment to and penetration of fallopian tube and nasopharyngeal mucosa by N. gonorrhoeae and N. meningitidis are similar or possibly identical.

Adhesiveness↗

PubMedDate not supplied

Red blood cell transfusions for elective hip and knee arthroplasty: opportunity to improve quality of care and documentation.

OBJECTIVES: To assess current practice for red blood cell transfusion relative to the American College of Physicians guideline for red blood cell transfusion; to determine comparative rates and relative appropriateness of autologous versus allogeneic blood use; and, to assess cost implications of current transfusion practices. DESIGN: Computerized quality-of-care algorithm applied retrospectively to medical-record and blood-bank data. SETTING: Twenty-six hospitals in Colorado, Connecticut, Georgia, Oklahoma, and Virginia. PATIENTS: Medicare beneficiaries (2,137) who were hospitalized in 1993 for two elective surgical procedures: total hip arthroplasty and total knee arthroplasty. Of the 1,195 patients who received a preoperative or postoperative transfusion, 728 were excluded from the analysis because the hospital medical record did not contain the clinical documentation necessary to apply the American College of Physicians guideline to each unit transfused. The remaining 467 patients comprised the sample. RESULTS: For 467 patients who underwent these two procedures and received a total of 651 units of preoperative or postoperative blood, there were 256 excess units transfused. Two hundred four of these units were autologous, and 52 were allogeneic. These excess units accounted for $48,200 of the total $121,000 direct cost of transfused units. CONCLUSIONS: These findings demonstrate that current medical records lack the documentation necessary to evaluate transfusion practice for the majority of Medicare beneficiaries undergoing elective hip and knee arthroplasty. The direct costs of preoperative and postoperative blood transfusion for these two procedures could be reduced by nearly 40% through adherence to the American College of Physicians guideline. The majority of this cost saving would be realized through reduction in unnecessary collection and use of autologous blood.

Algorithms↗