Staphylococcus intermedius in canine gingiva and canine-inflicted human wound infections: laboratory characterization of a newly recognized zoonotic pathogen.

Staphylococcal gingival flora was characterized in cultures from 135 dogs. Staphylococcus intermedius was isolated in 39% of the cultures, S. aureus was isolated in 10%, and both were isolated in 2.0%. S. aureus was isolated more often from dogs of working breeds with weights of greater than 40 lb (ca. 18 kg) and with outdoor habitats than was S. intermedius, which was associated with dogs of nonworking breeds with weights of less than 40 lb and indoor habitats. S. intermedius was distinguished from S. aureus by the following characteristics: coagulation of rabbit plasma at 4 h (26 versus 100%, respectively), hemolysis of sheep blood at 24 h (30 versus 79%, respectively), and mannitol fermentation at 24 h (4 versus 93%, respectively). A clear separation of the two species was apparent only with the acetoin (modified Voges-Proskauer) reaction (100% of the S. aureus isolates versus 0% of the S. intermedius isolates) and beta-galactosidase activity on the API Staph-Ident strip (0% of the S. aureus isolates and 100% of the S. intermedius isolates). Susceptibilities of S. intermedius and S. aureus were 72 and 7%, respectively, to penicillin G, and 100% of both species to oxacillin. Fourteen previously collected strains of coagulase-positive staphylococci from infected canine-inflicted human wounds were reanalyzed; 3 of 14 (21%) isolates were S. intermedius. We conclude that S. intermedius is a common canine gingival flora and is responsible for some canine-inflicted human wound infections, thus representing a newly recognized zoonotic pathogen.     

Fine structure and morphogenesis of spironolactone bodies in the zona glomerulosa of the human adrenal cortex

Numerous spironolactone bodies have been detected in the zona glomerulosa cells of the adrenal cortex of a 36-year-old spironolactone-treated woman whose non-tumorous right adrenal gland was removed surgically because of primary hyperaldosteronism. Electron microscopy revealed spherical laminated whorls which consisted of a central core composed of an amorphous electron-dense material surrounded by numerous smooth-walled concentric membranes. Continuous with and deriving from the endoplasmic reticulum, they were present in viable cells and were not associated with ultrastructural features indicating cellular injury. Cytoplasmic inclusions similar to spironolactone bodies can be detected in other organs after the administration of various compounds. Thus, they can be regarded as neither specific to spironolactone treatment nor exclusively inducible in the zona glomerulosa of the adrenal cortex.     

Expression of nonclassical MHC class Ib genes

Peptide binding proteins of the major histocompatibility complex consist of the “classical” class Ia and “nonclassical” class Ib genes. The gene organization and structure/function relationship of the various exons comprising class I proteins are very similar among the class Ia and class Ib genes. Although the tissue-specific patterns of expression of these two gene families are overlapping, many class Ib genes are distinguished by relative low abundance and/or limited tissue distribution. Further, many of the class Ib genes serve specialized roles in immune responses. Given that the coding sequences of the class Ia and class Ib genes are highly homologous we sought to examine the promoter regions of the various class Ib genes by comparison to the well characterized promoter elements regulating expression of the class Ia genes. This analysis revealed a surprising complexity of promoter structures among all class I genes and few instances of conservation of class Ia promoter regulatory elements among the class Ib genes.     

Inhibitory interaction in the cat's lateral geniculate nucleus

Summary Spike activities of optic tract fibers and corresponding relay cells were recorded simultaneously in layers A and A₁ of the dorsal lateral geniculate nucleus of the cat. Light stimuli of various diameters were shone into the receptive field center of these unit pairs and their input/output ratios were determined. An increase of the stimulus size leads to an impairment of the input/output ratio in on-center and off-center relay cells. This suppressive effect has approximately the same latency as the excitatory response.Intracellular recordings suggest that the inhibitory effect of the surround is due to a postsynaptic process. Inhibitory postsynaptic potentials occur during and — under certain stimulus conditions —before the excitatory response. The short latency of these IPSPs suggests that they result from the activity of adjacent units with the same RF characteristics as the recorded neuron. This inhibitory input is not restricted to the RF periphery but may also be activated by stimulation within the RF center. Most neurons are also inhibited by units with antagonistic center responses.During the period of this research Ernst Pöppel held a training grant of the Stiftung Volkswagenwerk, Az. 11 1015.     

Stroke following coronary-artery bypass surgery. A case-control estimate of the risk from carotid bruits

The causes of stroke following coronary-artery bypass surgery are largely unknown. To determine whether carotid bruits increase the risk of these events, we compared 54 patients with postoperative stroke or transient ischemic attacks with 54 randomly selected control patients. Both groups were drawn from 5915 consecutive patients who had coronary bypass surgery at our hospital from 1970 to 1984. Carotid bruits were noted preoperatively in 13 patients with postoperative stroke and in 4 control patients. Case-control analysis showed that the presence of carotid bruits increased the risk of stroke or transient ischemic attacks by 3.9-fold (95 percent confidence interval, 1.2 to 12.8; P less than 0.05). This increased risk remained essentially unchanged after adjustment for potentially confounding variables in a multiple logistic regression analysis. Other factors associated with a significantly increased risk (P less than 0.05) of these neurologic deficits were a history of stroke or transient ischemic attack (odds ratio, 6.0; 95 percent confidence interval, 1.6 to 22.1), a history of congestive heart failure (odds ratio, 5.3; confidence interval, 1.6 to 17.0), mitral regurgitation (odds ratio, 4.3; confidence interval, 1.4 to 12.9), postoperative atrial fibrillation (odds ratio, 3.0; confidence interval, 1.4 to 6.7), a cardiopulmonary-bypass pump time of more than two hours (odds ratio, 2.7; confidence interval, 1.1 to 6.7), and a previous myocardial infarction (odds ratio, 2.3; confidence interval, 1.1 to 5.1). We conclude that the presence of carotid bruits increases the risk of stroke after coronary-artery bypass surgery. However, the absolute magnitude of this risk, 2.9 percent, is small and comparable to the reported risk of stroke from carotid endarterectomy.     

The antigen-presenting environment in normal and human papillomavirus (HPV)-related premalignant cervical epithelium

The activation of HPV-specific T cells within the cervical microenvironment is likely to play an important part in the natural history of cervical intraepithelial neoplasia (CIN). The extent and the type of T cell activation will depend critically on the expression of MHC, costimulatory cell surface molecules and cytokines by keratinocytes and Langerhans cells within the cervical lesion. Expression of MHC class II (HLA-A-DR and -DQ), costimulatory/adhesion molecules (CD11a/18, CD50, CD54, CD58 and CD86) and cytokines (tumour necrosis factor-alpha (TNF-alpha) and IL-10) was therefore investigated by immunohistochemistry in normal squamous epithelium (n = 12), low-grade (n = 23) and high-grade (n = 18) squamous intraepithelial lesions of the cervix. CIN progression was associated with de novo expression of HLA-DR and CD54, and increased expression of CD58 by keratinocytes. However, significantly, there was no expression of any adhesion/costimulation molecule by epithelial Langerhans cells in any cervical biopsy studied. Furthermore, TNF-alpha, a potent activator of Langerhans cells, was expressed constitutively by basal keratinocytes in normal cervix (12+/12). but expression of this cytokine was absent in a number of CIN samples (20+/23 for low-grade, 12+/18 for high-grade CIN). Conversely, the suppressive cytokine IL-10 was absent in normal epithelium (0+/12), but was up-regulated in a number of CIN lesions (12+/23 for low-grade; 8+/18 for high-grade CIN). The restricted expression of costimulation/adhesion molecules and the nature of the cytokine microenvironment within the epithelium may act to limit effective immune responses in some CIN lesions.     

Tetrasomy 18p in a child with trisomy 18 phenotype

We report on a patient with trisomy 18 syndrome and tetrasomy 18p. The case indicates that the presence of an isochromosome i(18p) can mimic complete trisomy 18 syndrome.