Reactive oxygen intermediates mediate a systemic signal network in the establishment of plant immunity

Recognition of an avirulent pathogen stimulates an oxidative burst generating O2- and H2O2, and these reactive oxygen intermediates (ROIs) cue the induction of defense genes and cell death in the development of a restricted lesion. This localized hypersensitive response (HR) is accompanied by the development of systemic acquired resistance to virulent pathogens. Here we show that inoculation of Arabidopsis leaves with avirulent Pseudomonas syringae induces secondary oxidative bursts in discrete cells in distant tissues, leading to low-frequency systemic micro-HRs. The primary oxidative burst induces these systemic responses, and both the primary burst and the secondary microbursts are required for systemic immunity. Hence, ROIs mediate a reiterative signal network underlying systemic as well as local resistance responses.     

Manipulating ruminal fermentation: a microbial ecological perspective

The essential role of ruminal microflora in ruminant nutrition provides the potential for improvement in animal production via altering the numbers or activities of specific classes of microorganisms. Successful alterations will be facilitated by an understanding of the microbial ecology of the rumen based on its mechanistic underpinnings. Demonstrated improvements in ruminal fermentation can be traced to their consonance with well-established principles of microbial ecology (niche occupancy, selective pressure, adaptation, and interactions) and the thermodynamics and kinetics of substrate utilization. Application of these principles to several proposed alterations of the ruminal bacterial population allows a prediction of their relative feasibility. Improving fiber digestion, decreasing protein degradation, and detoxifying feed components that are present in low concentrations will be difficult to achieve in the rumen and are best approached by altering the feed, either genetically or with postharvest treatment. By contrast, the detoxification of feed components present in high concentration, and redirection of electron disposal away from methanogenesis, are more productive targets for microbiological research.     

Radionuclide studies in intestinal transplantation. Diagnosis of rejection and assessment of permeability

Three patients who received intestinal allografts were studied using two distinct radionuclide investigations. In the first, 111In or 99mTc-labeled leukocyte scanning was performed to assist in the diagnosis of rejection. It was able to demonstrate the occurrence of rejection in the transplanted intestine, and the response to antirejection therapy. In 1 case, the abnormality on the scan preceded the histological confirmation of rejection. The second technique studied mucosal integrity by serial 51Cr-EDTA/14C-mannitol permeability tests. These studies demonstrated the initial marked impairment and the slow return to normal function of the intestinal mucosal barrier. In 1 patient, this occurred by 91 days; in another, it took 232 days. A single assay performed in the third patient at the time of allograft rejection was also abnormal. Both radionuclide tests were helpful in the care of these complicated cases.     

Primary extranodal non-Hodgkin lymphoma of the oral cavity. An analysis of 34 cases

A case of macroglossia and resulting apertognathia because of primary amyloidosis in a 65-year-old man with multiple myeloma is described. In addition, a retrospective study of the oral manifestations of primary amyloidosis and multiple myeloma in the last 15 years is reported.     

Chronic tonsillitis

1. Maintenance of phosphate homeostasis is essential for energy producing and oxygen delivery systems, particularly, when the energy requirements are increased in certain conditions, such as septicaemia. We investigated the phosphaturic response to parathyroid hormone (PTH) in endotoxin (ETx)-treated rats in order to clarify the renal regulation of phosphate excretion during endotoxaemia. 2. Wistar rats that had undergone thyroparathyroidectomy were challenged with either Escherichia coli ETx (n = 8) or saline vehicle (n = 9). Thirty-minute renal clearance tests were done before and after PTH infusion. Rats infused with saline instead of PTH served as time controls for the ETx- (n = 7) and saline-treated (n = 8) rats. 3. In time control rats, ETx administration enhanced phosphate excretion progressively and this was associated with an obvious increase in the level of kidney adenosine 3', 5'-cyclic mono-phosphate (P < 0.005) compared with levels following saline vehicle administration. However, this phosphaturia in late-phase endotoxaemia was not observed in rats infused with PTH; ETx, but not saline vehicle, blunted the PTH-mediated increase in phosphate excretion (P < 0.005). Increased urinary noradrenaline and constant dopamine excretion were observed in endotoxaemic rats. Endotoxin administration produced marked metabolic acidosis and hypocapnia in comparison with the administration of the saline vehicle. 4. To test whether renal tubular sensitivity to parathyroid hormone related-protein (PTHrP) was enhanced during endotoxaemia, phosphaturic response to PTHrP in ETx- (n = 7) and saline-treated rats (n = 7) was examined. Parathyroid hormone related-protein infusion produced phosphaturia in both groups. However, the severity of the phosphaturia after PTHrP infusion was less in ETx-than in saline-treated rats. 5. In summary, although ETx administration causes a progressive increase in phosphate excretion in the absence of PTH, this is overcome by the antiphosphaturic effect of ETx, attenuating PTH-mediated phosphaturia after PTH infusion.