rifampin and Dehydration

Cyanobacteria inhabiting desert biological soil crusts must prepare towards dehydration, or their revival after rewetting is severely impaired. The mechanisms involved are unknown but signalling of forthcoming dehydration by dawn illumination was demonstrated. Accurate and reproducible simulation of desert conditions enabled examination of physiological activities and transcript profiles in a model organism, Leptolyngbya ohadii, in response to specific conditions. Exposure to far red light or lack of ground warming during dawn severely reduced revival after rewetting and altered the network of gene expression. The data implicated phytochromes in light and temperature sensing. Many genes were up- or down-regulated before water content decline, while others were strongly affected by the progression of dehydration and desiccation. Transcription continues during the desiccated phase but only barely during early rewetting, although photosynthetic activity was regained. Application of rifampicin with or without a preceding dehydration phase demonstrated that RNA is stabilized/protected during desiccation, possibly by intrinsically disordered proteins. We conclude that increasing light and temperature at dawn activates a network of genes that prepare the cells towards dehydration. Quick resumption of photosynthesis upon rewetting in contrast to the slow change in the transcript profile suggested that in addition to preparing towards dehydration the cells also prepare for forthcoming rewetting, during dehydration. Unravelling the presently unknown function of many responding genes will help to clarify the networks involved.

Topics: Bacterial Proteins; Cyanobacteria; Dehydration; Desert Climate; Gene Expression Regulation, Bacterial; Intrinsically Disordered Proteins; Light; Photosynthesis; Rifampin; Soil Microbiology; Temperature; Trehalose; Water

A 55-year-old Indian man presented with productive cough and a large left pleural effusion. Pleural fluid culture grew Mycobacterium tuberculosis, and he was started on antituberculosis therapy. One week later, the patient presented to hospital with drowsiness, dehydration and hypotension. He was transferred to critical care and only improved after starting hydrocortisone and stopping rifampicin. His short synACTHen test subsequently confirmed primary adrenal insufficiency, and a CT of the abdomen showed bilateral adrenal enlargement. Rifampicin is known to accelerate cortisol metabolism. We report the rare case of a rifampicin-induced adrenal crisis as a first presentation of Addison's disease in a patient with tuberculous infiltration of the adrenal glands.

Topics: Adrenal Glands; Adrenal Insufficiency; Antitubercular Agents; Cough; Dehydration; Humans; Hydrocortisone; Hypotension; Male; Middle Aged; Mycobacterium tuberculosis; Pleural Effusion; Rifampin; Sleep Stages; Treatment Outcome; Tuberculosis, Pulmonary

Topics: Acute Kidney Injury; Dehydration; Humans; Immunoglobulin Light Chains; Male; Middle Aged; Proteinuria; Rifampin

A patient who was receiving rifampin treatment for tuberculosis developed heterogenous light-chain proteinuria and insidious renal failure after a period of fluid restriction. The renal damage was characterized pathologically by an interstitial nephritis with invasive tubular casts and an associated renal vein thrombosis. The possible role of the light-chain proteinuria in the pathogenesis of the renal failure is discussed.

Topics: Acute Kidney Injury; Dehydration; Humans; Immunoglobulin Light Chains; Male; Middle Aged; Nephritis, Interstitial; Proteinuria; Rifampin