| gram-negative chemolithotrophic bacteria | <microbiology> A large group of bacteria including those which oxidise ammonia or nitrite, metabolise sulfur and sulfur compounds, or deposit iron and/or manganese oxides. (12 Dec 1998) |
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| gram-negative facultatively anaerobic rods | <microbiology> A large group of facultatively anaerobic, rod-shaped bacteria that show up as pink (negative) when treated by the gram-staining method. (12 Dec 1998) |
| gram-negative oxygenic photosynthetic bacteria | <microbiology> Widely distributed unicellular or multicellular bacteria. The cyanobacteria use chlorophyll a and phycobilins for oxygenic photosynthesis while genera in the prochlorales use both chlorophyll a and b but not phycobilins. (12 Dec 1998) |
| Gram's iodine | <microbiology> A solution containing iodine and potassium iodide, used in Gram's stain. (05 Mar 2000) |
| Gram's stain | <microbiology, technique> A method for differential staining of bacteria; smears are fixed by flaming, stained in a solution of crystal violet, treated with iodine solution, rinsed, decolorised, and then counterstained with safranin O. Gram-positive organisms stain purple black and Gram-negative organisms stain pink; useful in bacterial taxonomy and identification, and also in indicating fundamental differences in cell wall structure. (05 Mar 2000) |
| Gram stain | <microbiology, procedure> A method of staining bacteria using a violet stain. The gram staining characteristics (denoted as positive or negative) can assist in the identification of the offending bacteria. A heat fixed bacterial smear is stained with crystal violet (methyl violet), treated with 3% iodine/potassium iodide solution, washed with alcohol and counterstained. The method differentiates bacteria into two main classes, gram-positive and gram-negative. Certain bacteria, notably mycobacteria, that have walls with high lipid content show acid-fast staining the stain resists decolouration in strong acid. (27 Sep 1997) |
| Weigert-Gram stain | <technique> A stain for bacteria in tissues in which sections are stained in alum-haematoxylin, then in eosin, aniline methyl violet, and Lugol's solution. (05 Mar 2000) |
| half-a-gram stain | <technique> A lab technique used to detect the presence of members from the bacterial family Legionellaceae in samples of sputum. (09 Oct 1997) |
| Stirling's modification of Gram's stain | <technique> A stable aniline-crystal violet stain. (05 Mar 2000) |
| CD4-positive T-lymphocytes | A critical subpopulation of regulatory T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the t4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes, which includes both the helper-inducer (T-lymphocytes, helper-inducer) and suppressor-inducer (T-lymphocytes, suppressor-inducer) T-cells. (12 Dec 1998) |
| CD8-positive T-lymphocytes | A critical subpopulation of regulatory T-lymphocytes involved in MHC class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-lymphocytes, cytotoxic) and suppressor T-lymphocytes (T-lymphocytes, suppressor-effector). (12 Dec 1998) |
| continuous positive airway pressure | A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. (05 Mar 2000) |
| continuous positive pressure breathing | Artificial ventilation in which all inspirations are provided by positive pressure applied to the airway. Synonym: continuous positive pressure breathing, continuous positive pressure ventilation, intermittent positive pressure breathing, intermittent positive pressure ventilation. (05 Mar 2000) |
| continuous positive pressure ventilation | Synonym: controlled mechanical ventilation. (05 Mar 2000) |
| positive | Having a value greater than zero, indicating existence or presence of a condition, organism, etc. As chromatin positive or Wassermann positive, characterised by affirmation or cooperation. Origin: L. Positivus (18 Nov 1997) |