Symmetric infection of rotavirus on polarized human intestinal epithelial (Caco-2) cells.

When rotavirus infects the mature villus tip cells of the small intestine, it encounters a highly polarized epithelium. In order to understand this virus-cell interaction more completely, we utilized a cell culture-adapted rhesus rotavirus (RRV) to infect human intestinal (Caco-2) and Madin-Darby canine kidney (MDCK-1) polarized epithelial cells grown on a permeable support. Filter-grown Caco-2 cells and MDCK-1 cells, producing a transepithelial resistance of 300 to 500 and greater than 1,000 omega . cm2, respectively, were infected from either the apical or basolateral domain with RRV or Semliki Forest virus. Whereas Semliki Forest virus infection only occurred when input virions had access to the basolateral domain of MDCK-1 or Caco-2 cells, RRV infected MDCK-1 and Caco-2 monolayers in a symmetric manner. The effect of rotavirus infection on monolayer permeability was analyzed by measuring the transepithelial electrical resistance. Rotavirus infection on filter-grown Caco-2 cells caused a transmembrane leak at 18 h postinfection, before the development of the cytopathic effect (CPE) and extensive virus release. Electrical resistance was completely abolished between 24 and 36 h postinfection. Although no CPE could be detected on RRV-infected MDCK cells, the infection caused a transmembrane leak that totally abolished the electrical resistance at 18 to 24 h postinfection. Cell viability and the CPE analysis together with immunohistochemistry and immunofluorescence data indicated that the abolishment of resistance across the monolayer was due not to an effect on the plasma membrane of the cells but to an effect on the paracellular pathway limited by tight junctions. Attachment and penetration of rotavirus onto Caco-2 cells caused no measurable transmembrane leak during the first hour of infection.     

Avianca flight No. 052 accident: a plastic surgical perspective

The crash of Avianca Airlines flight no. 052 en route to JFK Airport on January 25, 1990, in Cove Neck, New York, resulted in the death of 72 passengers. Eighty-nine victims were admitted to 13 regional hospitals. Despite difficult access to the wooded crash site, early warning and prompt response by 37 volunteer fire and rescue units resulted in organized EMS triage and rapid hospital transport. This report reviews the specific injuries incurred, highlights the team management approach to a major aviation accident in a suburban area, and studies the likelihood of accidents of this magnitude. Thirty-eight patients triaged to two level I trauma centers, North Shore University Hospital-Cornell University Medical Center and Nassau County Medical Center, form the basis of this report. Seventeen patients were male; 21 were female. The average patient age was 33 years. Eight patients were children. The average length of stay was 30.9 days (range 2 to greater than 90 days). Twenty-six patients (including nonsurvivors) (68 percent) sustained significant multiple orthopedic injuries. The majority of fractures were open grade II to III tibia-fibula fractures. Bilaterality was commonly seen. Soft-tissue coverage of open long bone fractures was required in 10 patients (11 extremities) and included 3 microvascular muscle transfers, 7 muscle transposition flaps, and 3 skin grafts. Seven patients required open reduction and fixation of complex facial fractures (two of Le Fort II to III type, four of complex naso-orbital-ethmoid type). Plastic surgical repair of complex lacerations was common. Peripheral nerve exploration was required in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Determination of the origin of nondisjunction in a 49,XXXXY male using hypervariable dinucleotide repeat sequences

Summary We present a patient with a 49,XXXXY chromosome constitution in whom the origin of the extra X chromosomes was determined by analysis of five polymorphic CA (or GT) dinucleotide repeat sequences. This class of DNA marker has recently been demonstrated to be hypervariable with heterozygosity values up to 80%. By polymerase chain reaction (PCR) analysis of the dinucleotide repeat length polymorphisms, we have shown that all four X chromosomes were of maternal origin.     

The cytologic diagnosis of adenocarcinoma in situ of the cervix uteri and related lesions. II. Microinvasive adenocarcinoma

Criteria for the cytologic diagnosis of microinvasive adenocarcinoma of the cervix have not been previously established. Such cytologic criteria were evolved through the detailed analysis of cervical smears from 40 histologically confirmed cases. The cellular features of cervical adenocarcinoma in situ (AIS) were always associated with microinvasion. Syncytia of glandular cells, small cells in very crowded sheets and papillary groupings of cells, when seen in conjunction with AIS, were suggestive of microinvasion. Dissociation of cells was common. Nuclear pleomorphism with an irregular chromatin pattern and inconspicuous-to-prominent nucleoli was frequently present. In some cases, a tumor diathesis was seen in the smear background. Using these criteria, our predictive accuracy for diagnosing microinvasive cervical adenocarcinoma is improving steadily and now approaches 50%. Ongoing investigation of these cases must include a diagnostic come biopsy to further improve the predictive accuracy for this lesion.     

The amyloid percursor protein of Alzheimer disease is expressed as a 130 kDa polypeptide in various cultured cell types

The vascular and parenchymal amyloid deposits in Alzheimer disease (AD), normal aging and Down syndrome are mainly composed of a 4 kDa polypeptide (A4), which derives from a larger precursor protein (APP). There is evidence that APP is a transmembrane glycoprotein present in most tissues, but the characteristics of APP in intact cells are not yet known. In order to investigate this issue, we examined the immunoreactivity of fibroblasts of human and nonhuman cell lines with antisera raised to synthetic peptides corresponding to A4 and to two other domains of the APP. All three antisera recognized a 130 kDa polypeptide (APP-130) in immunoblots from all cell lines. In fibroblasts, an additional polypeptide of 228 kDa (APP-228) was recognized by the antiserum to A4. In immunoblots of two dimensional gels, APP-130 showed a pI of 6.2, while APP-228 failed to focus in the pH range of 4.7-7.0. Sequential extractions of cells with buffer and with Triton X-100 indicate that APP-130 is extractable with nonionic detergents at high ionic strength, whereas 228 kDa APP is a cystolic component. Immunofluorescence staining is consistent with an intracellular perinuclear and plasma membrane localization. It is concluded that APP-130 and APP-228 are two forms of the APP which result from extensive posttranslational modifications of a smaller original gene product. It is likely that APP undergoes similar posttranslational modifications in different cell types.     

Structure and transcription analysis of the gene encoding a cellobiase from Agrobacterium sp. strain ATCC 21400

The DNA sequence was determined for the cloned Agrobacterium sp. strain ATCC 21400 beta-glucosidase gene, abg. High-resolution nuclease S1 protection studies were used to map the abg mRNA 5' and 3' termini. A putative abg promoter was identified whose sequence shows similarities to the consensus promoter of Escherichia coli and with the nif promoter regions of Klebsiella. The abg coding sequence was 1,374 nucleotides long. The molecular weight of the enzyme, based on the predicted amino acid sequence, was 51,000. The observed Mr was 50,000 to 52,000. A region of deduced protein sequence was homologous to a region from two other beta-glucosidase sequences. This region of homology contained a putative active site by analogy with the active site of hen egg white lysozyme.     

Dual-Label Radioisotope Method for Simultaneously Measuring Bacterial Production and Metabolism in Natural Waters

Bacterial production and amino acid metabolism in aquatic systems can be estimated by simultaneous incubation of water samples with both tritiated methyl-thymidine and ¹⁴C-labeled amino acids. This dual-label method not only saves time, labor, and materials, but also allows determination of these two parameters in the same microbial subcommunity. Both organic carbon incorporation and respiration can be estimated. The results obtained with the dual-label technique are not significantly different from single-radiolabel methods over a wide range of bacterial activity. The method is particularly suitable for large-scale field programs and has been used successfully with eutrophic estuarine samples as well as with oligotrophic oceanic water. In the mesohaline portion of Chesapeake Bay, thymidine incorporation ranged seasonally from 2 to 635 pmol liter⁻¹ h⁻¹ and amino acid turnover rates ranged from 0.01 to 28.4% h⁻¹. Comparison of thymidine incorporation with amino acid turnover measurements made at a deep, midbay station in 1985 suggested a close coupling between bacterial production and amino acid metabolism during most of the year. However, production-specific amino acid turnover rates increased dramatically in deep bay waters during the spring phytoplankton bloom, indicating transient decoupling of bacterial production from metabolism. Ecological features such as this are readily detectable with the dual-label method.     

Inhibition of rabbit beta-globin synthesis by complementary oligonucleotides: identification of mRNA sites sensitive to inhibition

We tested the effects of a series of synthetic oligonucleotides (hybridons) complementary to the 5' noncoding and coding regions of rabbit beta-globin mRNA on endogenous protein synthesis in a rabbit reticulocyte cell-free translation system. With highly purified hybridons inhibition was completely specific for beta-globin. The sites most sensitive to inhibition are the beginning of the 5' noncoding region and a sequence including the initiation codon and several upstream bases. The region between these was relatively insensitive to inhibition. The sites of maximum sensitivity coincide with known protein binding sites, suggesting that hybridons exert their effects in part by blocking the binding of proteins required for translation. Their effectiveness seems related to the ease with which they are displaced by ribosomes.