Intratracheal administration of liposomal clodronate accelerates alveolar macrophage reconstitution following fetal liver transplantation

To facilitate study of alveolar macrophages in vivo, we developed a method to rapidly and efficiently replace resident alveolar macrophages with macrophages of a different (donor) genotype. Chimeric mice were generated by lethal irradiation followed by fetal liver transplantation (FLT) using green fluorescent protein (GFP) transgenic reporter mice as donors. Kinetics of peripheral blood monocyte (PBM) and alveolar macrophage reconstitution was determined 4 and 10 weeks post-FLT by quantifying the percentage of GFP+ cells. To enhance the recruitment of donor monocytes into the lung after FLT, mice were treated with intratracheal administration of liposomal clodronate to deplete host alveolar macrophages at 6 weeks post-FLT. PBM reconstitution occurred by 4 weeks after FLT (85.7+/-1.6% of CD11b+/Gr-1+ monocytes were GFP+), and minimal alveolar macrophage repopulation was observed (9.5% GFP+). By 10 weeks following FLT, 48% of alveolar macrophages were GFP+ by immunostaining of macrophages on lung tissue sections, and 55.1 +/- 1.6% of lung lavage macrophages were GFP+ by fluorescein-activated cell sorter analysis. Clodronate treatment resulted in a significant increase in GFP+ alveolar macrophages 10 weeks after FLT. By immunostaining, 90% of macrophages were GFP+ on lung tissue sections and 87.5 +/- 1.1% GFP+ in lung lavage (compared with GFP-transgenic controls). The ability of newly recruited alveolar macrophages to clear Pseudomonas aeruginosa and activate nuclear factor-kappaB in response to Eschericia coli lipopolysaccharide demonstrated normal macrophage function. Optimizing this methodology provides an important tool for the study of specific genes and their contribution to alveolar macrophage function in vivo.     

Exaggerated activation of nuclear factor-kappaB and altered IkappaB-beta processing in cystic fibrosis bronchial epithelial cells

In cystic fibrosis (CF), inflammatory mediator production by airway epithelial cells is a critical determinant of chronic airway inflammation. To determine whether altered signal transduction through the nuclear factor (NF)-kappaB pathway occurs in CF epithelial cells and results in excessive generation of inflammatory cytokines, we evaluated tumor necrosis factor (TNF)-alpha-induced production of the NF-kappaB-dependent cytokine interleukin (IL)-8 and activation of NF-kappaB in three different human bronchial epithelial cell lines: (1) BEAS cells that express wild-type CF transmembrane conductance regulator (CFTR), (2) IB3 cells with mutant CFTR, and (3) C38 cells, which are "corrected" IB3 cells complemented with wild-type CFTR. Treatment of cells with TNF-alpha (30 ng/ml) resulted in markedly elevated NF-kappaB activation and production of IL-8 by IB3 cells compared with BEAS and C38 cells. Despite the differences in NF- kappaB activation, no differences in basal levels of IkappaB-alpha or TNF-alpha- induced IkappaB-alpha processing and degradation were detected among the cell lines. In contrast, the basal level of IkappaB-beta was increased in the IB3 cells. Treatment with TNF-alpha resulted in increased formation of hypophosphorylated IkappaB-beta and increased nuclear localization of IkappaB-beta in IB3 cells compared with the other cell types. These findings provide additional evidence of a dysregulated inflammatory response in CF.     

Factors influencing host susceptibility to meningococcal disease

Host-parasite interactions influencing the development of the protective humoral immune response to Neisseria meningitidis are briefly reviewed. Possible consequences of the observed decreased titres of bactericidal activity specific for meningococcal serogroups A, B and C among patients with gonorrhoea are discussed with reference to: the epidemiology of the two diseases, the protective role of "natural" antibodies to the Neisseria species and the carriage rate of serogroupable strains of N. meningitidis among patients with gonorrhoea and a control population.     

An evaluation of three methods for determining colloid osmotic pressure

Plasma colloid osmotic pressure (COP) is an important determinant in edema formation. Three methods for assessing the COP were evaluated. Direct measurement of COP using the 4420 Wescor Colloid Osmometer was compared to the estimation of COP from both serum total protein and total serum solids (TSS) determinations. Blood samples from twenty adult patients (mean age = 64 years) undergoing cardiopulmonary bypass surgery were collected for COP assessment. Sample collection was performed prior to heparinization/hemodilution, during hypothermic bypass and at the conclusion of bypass following protamine administration. The results obtained from each method were analyzed by a two-way analysis of variance. The Bonferroni technique was used for comparison of sample means when the difference was significant (p less than 0.05). Correlations were reported by linear regression analysis. A statistically significant difference (p less than 0.01) was found between the three methods. A regression equation for the estimation of COP from total serum solids is offered: COP = (3.02 * TSS) + 0.65. Prospective clinical testing between the direct COP measurement and the estimation of COP from TSS using the equation (n = 38) revealed a significant correlation (R2 = .932) and no significant difference between the two (p greater than 0.05).     

RENAL TRANSPLANTATION – AN EARLY EXPERIENCE

Renal transplant (RT) is now a therapy of choice for end stage renal disease (ESRD). The Nephrology Unit, Asvini started functioning in Dec 90 and to date 1298 sittings of hemodialysis have been given to 45 patients. Of these, 35 were in ESRD and 11 patients underwent renal transplantation at this hospital during the period Jan 91 – Dec 93. One patient expired after 18 months of transplantation due to infection. Early experience in screening patients for RT, use of immunosuppression, management of rejection episodes and protocol are presented with special emphasis on its relevance to the Armed Forces.KEY WORDS: Transplantation, Renal Failure, Immunosuppression, Rejection     

The potential role of bacterial toxins in Sudden Infant Death Syndrome (SIDS)

Summary Toxigenic bacteria have been implicated in some cases of Sudden Infant Death Syndrome (SIDS). Although there is not much evidence thatClostridia spp. are associated with SIDS in Britain, strains ofStaphylococcus aureus producing pyrogenic toxins have been isolated from significant numbers of these infants at autopsy. The pyrogenic toxins, produced by some strains of group AStreptococcus pyogenes as well as staphylococci, are powerful superantigens that have significant physiological effects including induction of fever > 38°C. In this article, interactions between genetic and environmental factors that might enhance colonization of epithelial surfaces by toxigenic staphylococci are analyzed: infant's expression of Lewis^a antigen which acts as a receptor for some microorganisms; viral infections; the effect of mother's smoking on susceptibility to respiratory infection. Based on epidemiological findings and laboratory investigations, a hypothesis is proposed to explain how bacteria producing pyrogenic toxins might contribute to some cot deaths.     

Phospholipase A2 activity of guinea-pig isolated perfused lungs: stimulation, and inhibition by anti-inflammatory steroids

1 A simple double-isotope assay for phospholipase A2 activity of perfused organs is described; Guinea-pig lungs perfused through the pulmonary circulation exhibit a low background enzyme activity. This activity is blocked by dexamethasone, betamethasone and hydrocortisone, mepacrine, procaine or chlorpromazine. Aspirin and indomethacin are without effect. 3 Mechanical trauma, antigen challenge or injections of bradykinin, rabbit aorta contracting substance-releasing factor (RCS-RF) or histamine increase "basal" phospholipase activity. The effect of these agents, except that of bradykinin, is blocked by dexamethasone or mepacrine. 4 The blocking effect of steroids is cumulative and dose-dependent. They do not work in cell-free systems. Inhibition by mepacrine is rapid and is effective in cell-free lung homogenates. 5 It is suggested that agents which liberate prostaglandin endoperoxides and thromboxane A2 from perfused lungs do so by activating phospholipase A2.     

Tissue injuries associated with parenteral propylhexedrine abuse

Propylhexedrine, the active ingredient in Benzedrex Inhalers, is extracted from the wicks of the inhalers by drug abusers for intravenous injection to provide a "desirable high." Six representative cases treated over a one-year period are presented to exemplify the potential for soft tissue injury. Because the actual constituents of the injected material prepared from the inhalers were not established, solutions were prepared from Benzedrex Inhalers according to the formula provided by one of the patients. The extract was then subjected to vigorous qualitative and quantitative analyses; the presence of essentially pure propylhexedrine hydrochloride was confirmed in varying concentrations. To examine the progression of injury following injection of the prepared extract, the ears of 12 New Zealand white rabbits were injected either intra-arterially or subcutaneously. The opposite ear of each rabbit served as a control. Both clinical and pathologic observations demonstrated injury consistent with intense local vasoconstriction. Injury did not appear to relate to impurities in the solution or other embolic phenomena. Finally, the laboratory findings are discussed with regard to the clinical examples. In sum, the insult to tissue from intravascular or local injection with propylhexedrine appears to respond, although poorly, to efforts to reverse the intense pharmacologic vasoconstriction.