Increased virulence of a fibronectin-binding protein mutant of Staphylococcus aureus in a rat model of pneumonia

Fibronectin-binding proteins mediate Staphylococcus aureus internalization into nonphagocytic cells in vitro. We have investigated whether fibronectin-binding proteins are virulence factors in the pathogenesis of pneumonia by using S. aureus strain 8325-4 and isogenic mutants in which fibronectin-binding proteins were either deleted (DU5883) or overexpressed [DU5883(pFnBPA4)]. We first demonstrated that fibronectin-binding proteins mediate S. aureus internalization into alveolar epithelial cells in vitro and that S. aureus internalization into alveolar epithelial cells requires actin rearrangement and protein kinase activity. Second, we established a rat model of S. aureus-induced pneumonia and measured lung injury and bacterial survival at 24 and 96 h postinoculation. S. aureus growth and the extent of lung injury were both increased in rats inoculated with the deletion mutant (DU5883) in comparison with rats inoculated with the wild-type (8325-4) and the fibronectin-binding protein-overexpressing strain DU5883(pFnBPA4) at 24 h postinfection. Morphological evaluation of infected lungs at the light and electron microscopic levels demonstrated that S. aureus was present within neutrophils from both 8325-4- and DU5883-inoculated lungs. Our data suggest that fibronectin-binding protein-mediated internalization into alveolar epithelial cells is not a virulence mechanism in a rat model of pneumonia. Instead, our data suggest that fibronectin-binding proteins decrease the virulence of S. aureus in pneumonia.     

Use of monoclonal antibodies for the histopathological diagnosis of human malignancy

This paper describes the use of a panel of seven monoclonal antibodies (selected so as to include reagents reactive with both epithelial and lymphoid cells) for distinguishing between anaplastic carcinoma and high grade lymphoma. Details are given of the immunohistological reactions of these antibodies against a wide range of both normal and malignant tissues and of a number of practical instances in which use of the antibody panel enabled a diagnosis to be made when routine histological examination had been inconclusive.     

Ultrastructural and virological aspects of Langat virus-induced SSPE in suckling hamsters.

The morphology of subacute sclerosing panencephalitis (SSPE) lesions in hamsters following i.p. inoculation of Langat virus was studied by light microscopy and electron microscopy. The lesions' temporal relationship to virus presence and antibody production was studied by immunofluorescence, virus isolation from brains and brain cell cultures, and by antibody assay of serum and spinal fluid. All 10-day-old hamsters infected with Langat virus developed SSPE lesions, most prominently in the cerebellum, without any overt signs. The lesions appeared 10 days after infection, progressed in severity until Day 21 and persisted unaltered at least 3 months. They consisted of neuronal degeneration, calcification, and intracellular lipid accumulation. Virus was isolated from Days 3 to 15 and disappeared on Day 21. Demonstration by cerebellar immunofluorescence of viral antigen was observed 10 days after inoculation. Antibody appeared in the serum on Day 6, rose to very high titres by Day 21, and thereafter declined. Cell-associated virus was not demonstrable in negative brain-cell cultures. These findings suggest that SSPE in hamsters, associated with Langat virus infection, is biologically different from measles SSPE. Purkinje-cell lipid accumulation and mineralization sparing mitochondria were manifestations of the response of neurons to cell injury at the threshold of irreversibility.     

Exogenous myeloperoxidase enhances bacterial phagocytosis and intracellular killing by macrophages.

It is well documented that myeloperoxidase (MyPo) contributes to the bacterial activities of neutrophils and monocytes. Since mature macrophages (M phi) are devoid of this enzyme, its participation in M phi-mediated phagocytes and bacterial killing has not been completely defined. The present study demonstrates the exogenously added MyPo, at physiological levels, enhances both phagocytosis and killing of Escherichia coli. Murine peritoneal M phi were exposed to various concentrations of MyPo for different time intervals. Viable opsonized E. coli was added either prior to or after addition of MyPo. Thioglycolate-induced but not resident M pho exhibited an increase in the number of phagocytizing cells. Both resident and thioglycolate-induced M phi demonstrated increased bactericidal activity. Physiological levels of soluble MyPo also induced a significant increase in chemiluminescence. Since luminol-dependent chemiluminescence measures reactive oxygen intermediate production, studies were done to determine whether superoxide anion or H2O2 was involved in MyPo-induced M pho killing. Both superoxide dismutase and catalase ablated MyPo-induced bactericidal activity. The above data suggest that soluble MyPo, released from neutrophils at a site of infection or inflammation, can enhance both phagocytosis and killing of microorganisms.     

Microsatellite instability and mutation analysis of hMSH2 and hMLH1 in patients with sporadic, familial and hereditary colorectal cancer

To date, at least four genes involved in DNA mismatch repair, hMSH2, hMLH1, hPMS1 and hPMS2, have been demonstrated to be altered in the germline of patients with hereditary nonpolyposis colorectal cancer (HNPCC). Additionally, defective mismatch repair is thought to account for the observation of microsatellite instability (MIN) in tumors from these patients. The genetic defect responsible for the MIN+ phenotype in sporadic colorectal cancer, however, has yet to be clearly delineated. In order to better understand the role of somatic and germline alterations within hMSH2 and hMLH1 in the process of colorectal tumorigenesis, we examined the entire coding regions of both of these genes in seven patients with MIN+ sporadic colorectal cancer, 19 patients with familial colorectal cancer, and 20 patients meeting the strict Amsterdam criteria for HNPCC. Thirteen germline, two somatic, and four neutral alterations were identified. The two somatic mutations occurred in patients having familial cancer, while the germline mutations were distributed among one sporadic (14%), three familial (16%), and nine HNPCC (45%) cases. All patients with identified mutations in the mismatch repair genes, whose tumors were available for analysis, demonstrated MIN. On the other hand, we could not identify mutations in the subset of clinically defined HNPCC patients with MIN negative tumors nor in the majority (6/7) of MIN+ sporadic tumors.      

Symposium: reproduction in baboons. From blastocyst to placenta: the morphology of implantation in the baboon

Implantation and placentation in the baboons share many morphologicalfeatures with other primates, as well as having some specificdistinctions. The ability to use deturgescence of the sex skinas a method of timing ovulation and the ease with which theuterine lumen can be flushed have been used to examine morphologicalaspects of blastocyst differentiation and implantation in thisspecies. Preimplantation blastocysts were obtained by non-surgicalflushing of the uterus 68 days after ovulation, and implantationsites were excised from uteri removed on days 10-16 of gestation.All tissues were prepared for electron microscopy by aldehydefixation and plastic embedding. Maturation of trophoblast fromthe compacted morula stage to the expanded blastocyst stageincludes increase in numbers of polyribosomes, changes in conformationof mitochondria, and development of an effective endocytic apparatus.An endodermal layer forms beneath the inner cell mass priorto loss of the zona pellucida, and parietal endodermal cellsextend beyond the inner cell mass. Azonal blastocysts have regionsof syncytial trophoblast adjacent to the inner cell mass, andthey may represent adhesion stages of early implantation. Inearly postimplantation stages, trophoblast replaces the uterineepithelium and processes of syncytial trophoblast invade dilatedsuperficial maternal vessels. In subsequent lacunar stages thereis rapid elevation of the developing conceptus above the uterinesurface as the lacunae enlarge. Cytotrophoblast rapidly entersmaternal vessels, and arterioles are partially or completelyoccluded by migrating cytotrophoblast. The early access to controlledmaternal blood flow apparently allows trophoblastic lacunaeto expand superficially as opposed to more extensive endometrialinvasion.     

Detrusor myopathy in young beagle dogs

Hematoxylin and eosin-stained sections of urinary bladder were examined microscopically from 449 male and female beagle dogs after 2- to 4-week toxicology studies. Degenerative lesions (detrusor myopathy) of the urinary bladder muscular tunic were present in 59 of 449 (13%) dogs. Myopathic lesions consisted of focal to multifocal areas of smooth muscle fiber atrophy with cytoplasmic basophilia and vacuolation, individual cell necrosis, enlarged smooth muscle nuclei and nucleoli, and occasional mitotic figures. Adjacent areas of arteritis and periarteritis were present in 10 of 59 (17%) beagles with detrusor myopathy suggesting a possible ischemic pathogenesis of the smooth muscle lesions. There was no significant difference in prevalence of myopathy in beagles administered vehicle or various test compounds. Prior urinary catheterization procedures appeared to augment the prevalence of myopathy; some lesions were adjacent to minor, iatrogenically traumatized urinary bladder mucosa. Muscle lesions were not observed in urinary bladders from mongrel dogs, monkeys, cats, rats, or microswine. When compared to crossbred dogs and other laboratory species, the beagle dog thus appears to be sensitive to development of detrusor myopathy.     

Working with communities for health

Nurses must continue to build links with communities to enable communities to control their own health outcomes.     

Bone resorption levels by age and menopausal status in 5,157 women

OBJECTIVE: The purpose of this study was to describe bone resorption activity using a biochemical marker according to the categories of age, menopausal status, and selected drug/supplement use in middle-aged and elderly community-based women. DESIGN: This was a cross-sectional study that assessed urinary cross-linked N-telopeptide of type I collagen (NTx) and used self-report data to group women as premenopausal (Pre), perimenopausal (Peri), postmenopausal without hormone replacement therapy (Post), and postmenopausal with hormone replacement therapy (HRT). RESULTS: Mean NTx values were found to be significantly different by group and controlling for age (p = 0.001), with post hoc tests showing all pairwise group comparisons as significantly different (p = 0.001), except that the Pre and HRT groups were not significantly different. Both the Peri and the Post NTx levels were significantly higher than the Pre and the HRT groups'. NTx values in the Peri group varied with age-the youngest Peri women were similar to Pre women, and the oldest Peri women were similar to Post women. Significantly lower NTx levels were found only in the Post (p = 0.009) and HRT (p < 0.001) groups using diuretics compared with nonuse and only in the HRT group using calcium supplements compared with nonuse (p = 0.006). No differences by thyroid use were found. With a biochemical marker, the results showed that bone resorption activity differences could be demarcated in women according to age, estimated menopausal stage, and selected drug/supplement use. CONCLUSIONS: These results support the usefulness of NTx assessment for indicating bone resorption activity and therefore the potential for osteoporosis or for monitoring the efficacy of antiresorptive therapies.