Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The combination of skin loss and immune depression after thermal injury predisposes burn patients to an increased risk of infection. Since the commonest site of infection in the burn patient is the burn wound itself, we elected to study the opsonic activity of locally produced blister fluid, from 18 thermally injured patients, for the two most common organisms colonizing the burn wound (Pseudomonas aeruginosa and Staphylococcus aureus). Blister fluid was as good an opsonin source for staphylococcus as normal serum. In contrast, the blister fluid did not support either the phagocytosis of the intracellular killing of P. aeruginosa. The poor opsonic activity of blister fluid for P. aeruginosa did not appear to be due to the presence of an inhibitory factor(s) since the addition of normal serum restored the opsonic activity of the blister fluid to normal. The concentrations of immunoglobulins and the complement components C3 and C4 in the blister fluid samples were less than half the level of those in normal serum. The opsonic activity of the blister fluid could not be restored to normal by the addition of either immunoglobulin or heat-inactivated serum (56 degrees C for 30 min). Thus, the opsonic factor(s) missing from the blister fluid was heat labile and thus probably represents complement components. That blister fluid had impaired opsonic activity for P. aeruginosa but not for S. aureus indicated that a local humoral defect may be responsible, at least in part, for the high incidence of gram-negative organisms, especially pseudomonads, colonizing the burn wound after thermal injury.
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PMID:Opsonic activity of blister fluid from burn patients. 641 19

Depression of beta-lactamases in certain non-fastidious Gram-negative bacilli has been responsible for (i) the rapid development of resistance to a variety of beta-lactam antibiotics and (ii) antagonism between beta-lactam antibiotics. Therefore, the effects of a variety of inhibitors of macro-molecular synthesis on derepression of beta-lactamase were investigated with four strains each of enterobacter and Pseudomonas aeruginosa. When tested at concentrations that were not inhibitory to growth, clindamycin was the most effective inhibitor of derepression of beta-lactamases in some of the strains examined. In one enterobacter isolate, clindamycin completely prevented derepression of beta-lactamases. This effect was highly specific as clindamycin did not influence constitutive beta-lactamase or depression of other inducible enzymes in this same strain. These results suggest that clindamycin may selectively inhibit synthesis of beta-lactamase under repressor control in some bacteria without affecting synthesis of other proteins or replication. Such selective inhibition may provide a new approach for the enhancement of the antibacterial activity of certain beta-lactam antibiotics.
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PMID:Effects of clindamycin on derepression of beta-lactamases in gram-negative bacteria. 641 3

The purpose of this study was to evaluate the effects of high and low therapeutic doses of methotrexate (MTX) on macrophage metabolism and function in vitro. Monolayers of elicited rat peritoneal macrophages (PM) were exposed to a wide range of MTX concentrations (10(-8) M-10(-3) M) for 24 or 48 hr and macrophage RNA and protein metabolism were evaluated by the incorporation of [3H]5-uridine and [14C]1-leucine, respectively, into trichloroacetic acid (TCA)-precipitable material. Macrophage functional activity was examined by measuring the uptake of [14C]Pseudomonas aeruginosa to assess phagocytosis and the release of 51Cr from antibody-coated [51Cr]sheep red blood cells (SRBC) to assess antibody-dependent cell-mediated cytotoxicity. Following a 24-hr incubation with 10(-3) M MTX, incorporation of [3H]5-uridine into PM monolayers was enhanced 79% when compared to control monolayers (p less than 0.005). Washout studies revealed that the stimulation of uridine incorporation was no longer observed by 24 hr following the removal of MTX from the culture medium. Incubation with 10(-3) M MTX for 48 hr returned uridine incorporation to control levels, although leucine incorporation into protein was reduced by 22% (p less than 0.01). The depression in leucine incorporation in the presence of 10(-3) M MTX was not reversed after the removal of MTX from the culture medium. Uptake of [14C]P. aeruginosa was not altered following a 24- or 48-hr incubation with either 10(-7) M or 10(-3) M MTX. Similarly, [51Cr]SRBC cytolysis was not affected by a 2-hr preincubation with and continuous exposure to between 10(-8) M and 10(-3) M MTX. These results demonstrate that incubation of inflammatory macrophages with clinically high doses of MTX can alter macrophage RNA and protein metabolism without producing demonstrable changes in macrophage functional activity.
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PMID:Functional resistance of inflammatory macrophages to methotrexate in vitro. 642 43

The local enhancement of infection by exogenous ferric iron, as ferric ammonium citrate, and by ferrous iron as guinea-pig haemoglobin, was assessed in studies with 55 strains of bacteria injected into the skin of guinea-pigs. The test organisms included Staphylococcus aureus, Streptococcus spp., Klebsiella spp., Escherichia coli and Pseudomonas aeruginosa. Four strains of Bacteroides spp. were tested with haemoglobin only. As previously reported with other strains, enhancement of infection by members of a given species by ferric iron was variable; in this study infection with only 11 of 59 strains was enhanced. Haemoglobin either of equal or lesser iron content was a more potent enhancer, affecting 27 of the 59 strains. The enhancement ranged from two-fold to 80-fold, the higher figures on the whole being characteristic of haemoglobin enhancement. Some few instances of depression by both haemoglobin and ferric ammonium citrate were noted. A few tests were made with systemic haemoglobin but the concentrations attainable were largely ineffective. Enhancement of infection did not appear to be related to the capacity of a strain to lyse or digest host red blood cells. In so far as guinea-pigs, whose antibacterial defences are lowered by ferric or ferrous iron, represent human subjects at risk of infection because of clinical circumstances characterised by excess of available iron--either exogenous or as a result of haemolysis--our results with organisms of a kind commonly associated with infection in hospitals suggest that only a small proportion of environmental bacteria can take advantage of any decreased resistance associated with iron excess.
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PMID:The variable response of bacteria to free haemoglobin in the tissues. 643 25

We report bacterial interference with urine osmolality measurements using an instrument based on the principle of freezing point depression. Although the exact nature of the interfering activity has not been defined, the phenomenon is associated with a bacterium, identified as Pseudomonas putida, and is removed from the specimens by filtration at 0.45 micron. The bacteria led to osmometer dysfunction presumably by acting as a nidus for crystallization and preventing proper supercooling of specimens.
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PMID:Bacterial interference with urine osmolality measurements. 661 12

Pulmonary atelectasis predisposes the lung to infection. This condition may be partly due to impaired cellular immune response of the collapsed lung segment. We postulated that atelectasis may affect alveolar macrophage (AM) antibacterial function. To test this hypothesis, atelectasis was induced in the right upper lobes of piglet lungs. Alveolar macrophages harvested by bronchoalveolar lavage of collapsed segments for up to 24 hours showed progressive depression of their phagocytic activity against Pseudomonas aeruginosa in vitro. However, their intracellular bactericidal activity did not change. Reexpansion of the atelectatic lobes with mechanical ventilation and 100% oxygen supplementation for four hours after six hours of atelectasis resulted in reversal of the impaired AM phagocytic activity. These observations presented insight into the mechanisms of susceptibility to lung infection in pulmonary atelectasis and the potential for its reversal.
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PMID:The effects of pulmonary atelectasis and reexpansion on lung cellular immune defenses. 669 20

Pulmonary infection complicating intra-abdominal abscess is a major clinical problem. One hundred and forty-three patients with abdominal abscesses were reviewed; 41 had associated pneumonia by strictly defined criteria. The causative organisms for the pneumonia were Pseudomonas (35), Klebsiella (20), and Enterobacter (16), while abdominal infections were caused by Escherichia coli (22), Klebsiella (21), and Enterococcus (18). The temporal and bacteriologic relationship between the abdominal and pulmonary infection suggested that decreased pulmonary host defenses might be operative in the high incidence of pneumonia observed. An experimental model for intra-abdominal abscess was created using cecal ligation in the rat. Animals with an abdominal abscess had a marked depression of their ability to clear E. coli and Pseudomonas aeruginosa that were injected into the airway. Macrophages from infected animals did not differ in quantity or viability when compared with those in control animals. The ability to ingest bacteria appeared to be normal or enhanced in infected animals, but there was a significant decrease in the ability of the macrophage to kill the ingested organisms. Such macrophage defects may be partially responsible for the infected animals' inability to clear bacteria in a normal manner.
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PMID:Pulmonary infection complicating intra-abdominal sepsis: clinical and experimental observations. 704 21

The resting O(2) consumption of alveolar and peritoneal macrophages obtained from rats at 4 and 24 h after thermal injury was unaltered from control values. However, when heat-killed Pseudomonas aeruginosa or polystyrene latex particles were added to the cell suspensions to initiate phagocytosis, a significant depression in the respiratory burst accompanying the phagocytic event was demonstrated. The addition of phorbol myristate acetate, used to maximize the respiratory response, was ineffective in elevating, to control values, the respiratory burst of macrophages obtained from burned animals. The deficit was only, in part, serum mediated since the responses could not be restored to control values even when the cells from the burned animals were vigorously washed with control serum and incubated with control serum. The contribution of a burn serum factor, which was non-dialyzable, heat stable at 56 degrees C but not at 65 degrees C, and insensitive to pronase treatment, must be considered. These data indicate that thermal injury results in macrophage metabolic alterations which are mediated, in part, by a burn serum factor. Furthermore, the data suggest that pulmonary alveolar macrophages are more sensitive to thermal injury than peritoneal macrophages. Serum factors contributed, in part, to this observed impairment in the respiratory burst as indicated by: (i) an approximate 50% reversal of the impairment by control serum, and (ii) an approximate decrease of 50 to 80% in the control alveolar macrophage respiratory burst when serum from the thermally injured rats was added to the culture medium.
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PMID:Depression of the respiratory burst in alveolar and peritoneal macrophages after thermal injury. 722 87

Most polyhydroxyalkanoates (PHAs) reported to date fall into one of two broad classes: either hydroxybutyrate-hydroxyvalerate copolymers (typified by the PHA produced by Alcaligenes eutrophus), or hydroxyoctanoate-rich heteropolymers (typified by the PHA produced by Pseudomonas oleovorans). Few reports of copolymers rich in hydroxybutyrate (HB), but containing a minor proportion of a co-monomer with a higher carbon number than valerate, have appeared. Here we report on the biosynthesis and characterization of HB-rich polymers containing 2-4 mol% of hydroxycaproate (HC) units, as well as a terpolymer containing HC and hydroxyoctanoate (HO) units. These polymers were produced in good yield by Comomonas testosteroni, Bacillus cereus and an unidentified third organism when grown on caproate or octanoate. The minor co-monomers were found to be rejected from the PHB crystallites by X-ray analysis and by quantitative analysis of the melting point depression. The greatly reduced melting point, coupled with the retention of a high degree of crystallinity, could make these materials attractive as melt-processible thermoplastics.
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PMID:Biosynthesis and characterization of hydroxybutyrate-hydroxycaproate copolymers. 754 20

Burn wound sepsis is the most common and severe complication in the patients with severe burn. To know the systemic and local defect in immunity of burned patients, we measured the luminol-enhanced chemiluminescence (CL) response of normal polymorphonuclear leukocytes (PMNs) upon exposure to zymosan particles, bacteria or Candida albicans that were opsonized with any of patient's serum, blister fluid of burn wound or pooled normal serum (blood type AB). Sera from patients exhibited lower opsonic activities than those of pooled normal serum in the early postburn days. The levels of serum immunoglobulins, complement components and plasma fibronectin were found to correlate well with opsonin-index (OI), which was determined based on the CL response data obtained during the course of infusion therapy with fresh frozen plasma. Furthermore, patient's blister fluid showed much lower opsonic activity against bacteria such as Pseudomonas aeruginosa than patient's own serum. These results indicate that blister fluid is also not effective to opsonize bacteria because of the marked depression of the levels of immunoglobulins and complement components. Destruction of the skin barrier by thermal injury and impairment of systemic or local humoral immunity may predispose these patients to burn wound sepsis.
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PMID:Opsonic activity of sera and blister fluid from severely burned patients evaluated by a chemiluminescence method. 793 62


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