Specific binding of IL-8 to rabbit alpha-macroglobulin modulates IL-8 function in the lung.

OBJECTIVE AND DESIGN: The purpose of this study was to compare chemotactic activity of IL-8 alone with that of IL-8 reacted with rabbit alpha-macroglobulins (alphaM) in vivo. METHODS: Initially the binding of recombinant human IL-8 (rhIL-8) to rabbit alphaM was studied. 125I-labeled rhIL-8 was incubated with alphaM, and electrophoresed on native 5% gels or SDS-polyacrylamide 4-20% gradient gels. Next, rhIL-8 or rhIL-8 bound to alphaM was administered via an endotracheal tube to rabbit's lungs. TREATMENT: An endotracheal tube was wedged into a segment of the lobe of each lung, and a sample instilled through the tube into this segment. After 4 h the lungs were lavaged. RESULTS: rhIL-8 bound to alphaM retained its full chemotactic activity in vitro but exhibited a diminished ability to induce the influx of neutrophils into the rabbit lung. CONCLUSIONS: The data suggest that alphaM may facilitate IL-8 clearance from the lung.

Involvement of alpha-2-macroglobulin receptor in clearance of interleukin 8-alpha-2-macroglobulin complexes by human alveolar macrophages.

The purpose of this study was to determine if interleukin 8 (IL-8) in complex with alpha2-macroglobulin (alpha-2-M) can be taken up by human alveolar macrophages. First, we demonstrated that human alveolar macrophages have receptors for alpha-2-M but not IL-8. The binding of(125)I-labeled alpha-2-M to the cells was specific and saturable, whereas(125)I-labeled recombinant human IL-8 (rhIL-8) did not bind to macrophages. However,(125)I-rhIL-8-alpha-2-M complexes bound to macrophages, and unlabeled alpha-2-M competed for the binding. We then cultured the cells in the presence of(125)I-rhIL-8-alpha-2-M complexes,(125)I-rhIL-8 alone or buffer for 24 h. Macrophages were lysed, and the released radioactivity measured. IL-8 concentrations in supernatants and cells were also measured using an IL-8 ELISA. When the macrophages were incubated with(125)I-rhIL-8-alpha-2-M complexes there was a significant amount of IL-8 associated with the cells. However, this was not the case when the cells were incubated with(125)I- rhIL-8 alone suggesting that only these complexes were taken-up by human alveolar macrophages. Furthermore, the clearance of complexes was specifically inhibited by a monoclonal antibody against the 515-kDa subunit of the alpha-2-M receptor (alpha-2-MR) but not by an isotopic mouse IgG1. The study shows an important clearance mechanism for IL-8 in the lung.

Changes in aortic levels of tropoelastin mRNA following treatment of rats with the antihypertensive drugs captopril and hydralazine.

This manuscript describes changes in the steady state levels of aortic tropoelastin mRNA in spontaneously hypertensive rats (SHR) and normotensive controls (WKY) following treatment with two antihypertensive drugs. Three-week-old WKY and SHR rats were treated with hydralazine (15 mg/kg/day) or captopril (25 mg/kg/day). Tail artery blood pressure was monitored twice weekly. Both drugs prevented the development of hypertension in the SHR rat. At 6 weeks of age, total aortic RNA was extracted and the steady state levels of mRNAs coding for tropoelastin and pro alpha 1 (III) collagen were determined by slot blot hybridization analysis using radiolabeled tropoelastin and pro alpha 1 (III) collagen cDNA clones. Hydralazine treatment resulted in a threefold increase in tropoelastin mRNA levels in both the SHR and the WKY animals (P less than 0.01). Captopril-treated SHR animals demonstrated a similar significant increase. In contrast, no differences in pro alpha 1 (III) collagen mRNA levels were observed in the aorta of SHR or WKY rats following treatment with either captopril or hydralazine. These data suggest that antihypertensive agents can act specifically to directly induce tropoelastin mRNA levels in large arteries and thus may induce vascular remodeling independent of an increase in blood pressure.

Morphine cholescintigraphy.

Radionuclide cholescintigraphy (RC) is a useful adjunctive diagnostic tool for the identification of acute cholecystitis. False-positive rates, that is, nonvisualization, of 10 to 38 per cent have been reported in patients with factors associated with nonfilling of the gallbladder, such as prolonged fasting and the administration of total parenteral nutrition, pancreatitis, alcoholism or other critical illnesses. The administration of morphine sulfate increases resting pressure of the common bile duct because of constriction of the sphincter of Oddi, and increases the likelihood of gallbladder visualization. We administered morphine sulfate (0.05 to 0.1 milligram per kilogram given intravenously) to 68 patients (including 25 critically ill patients) suspected of having biliary sepsis and who demonstrated nonvisualization of the gallbladder by RC at 30 to 60 minutes. Visualization of the gallbladder occurred within 60 minutes after the administration of morphine sulfate in 38 patients and within 30 minutes in 36 of the 38, aiding in exclusion of the diagnosis of acute cholecystitis in 37 patients. Acute cholecystitis was confirmed by laparotomy in 28 of the remaining 31 patients. There were two false-positive and one false-negative scans, yielding a sensitivity rate of 97 per cent, a specificity rate of 95 per cent, positive and negative predictive values of 0.93 and 0.97, and an accuracy of 96 per cent for this investigative procedure. We conclude that administration of morphine sulfate in conjunction with RC in seriously ill patients enhances the reliability of this test.

Use of cholescintigraphy with morphine in critically ill patients with suspected cholecystitis.

Diagnosis of acute cholecystitis in critically ill patients is often difficult; clinical signs are subtle, and radiologic tests are nonspecific and have a high incidence of false-positive results. This study reviews our experience with intravenous morphine sulfate as an adjunct to promote gallbladder filling in 18 critically ill patients who demonstrated nonvisualization of the gallbladder during cholescintigraphy performed as part of a diagnostic workup for occult sepsis. Findings suggestive of a biliary source included fever, leukocytosis, abdominal tenderness, abnormal liver function test results, fasting, and total parenteral nutrition. Morphine was administered to all 18 patients after nonvisualization of the gallbladder; in 17 cases prompt visualization was noted, thus excluding cystic duct obstruction. The remaining patient underwent operation for acalculous cholecystitis. None of the 17 patients whose gallbladders were visualized had a subsequent clinical course consistent with untreated biliary sepsis. Radionuclide cholescintigraphy with morphine appears to be useful in the evaluation of critically ill patients with suspected biliary sepsis. It is particularly helpful in confirming or excluding the diagnosis of acute acalculous cholecystitis in patients who are fasting or receiving total parenteral nutrition and initially demonstrate nonvisualization of the gallbladder and in patients who have previously documented gallstones.

Abdominal candidiasis in surgical patients.

Although abdominal candidiasis in critically ill surgical patients is becoming increasingly common, optimal management has not been defined. We treated 16 patients with abdominal candidiasis over a 36 month period. Violation of the gastrointestinal tract mucosa was the most common precipitating event (13 patients). Predisposing factors included: CVP catheters, broad spectrum antibiotics, and parenteral hyperalimentation in all patients, H2-blockers/antacids in 14 patients, as well as malnutrition (7 patients), DM (3 patients), alcoholism (3 patients), and steroids/chemotherapy (3 patients). Candida was isolated from an abscess in seven patients, peritoneal fluid in six patients and both in three patients. In four patients abdominal candidiasis was preceded by positive cultures from blood or two peripheral sites which had not been treated. All patients were treated with amphotericin B (146-4000 mg) without any major adverse effects. Fungal infection was eradicated in ten patients; three patients succumbed to candidiasis. Patients treated within seven days required less Amphotericin B and appeared to have a better outcome than those having delayed treatment. The authors conclude that abdominal candidiasis is a potentially lethal infection in critically ill surgical patients that should be aggressively treated. Amphotericin B can be safely administered and concurrent antibiotics need not be stopped.

Strain differences in pituitary prolactin content: relationship to number of hypothalamic dopamine neurons.

BALB/cJ mice have more tuberoinfundibular dopamine neurons, and thus greater tyrosine hydroxylase activity, than CBA/J mice. Strain differences in the synthesis and release of prolactin would also be predicted since dopamine released from the tuberoinfundibular neurons is the prolactin inhibitory factor which plays a role in the regulation of both prolactin synthesis and release. As expected, CBA/J mice, with fewer dopamine neurons, synthesized and released significantly more prolactin than BALB/cJ mice; that is, both pituitary and serum prolactin concentrations were greater in CBA/J mice. To determine if there were more cells containing prolactin or more prolactin per cell, pituitaries were stained with antibodies to prolactin and densitometric analysis made of both the average staining per unit area and total staining per pituitary. For both indices CBA/J mice had more staining than BALB/cJ mice. Using these criteria the difference in staining was attributed to more prolactin-stained lactotrophs in the CBA/J strain. Although no differences in the number of acidophils demonstrated by Pearse Trichrome method were observed, acidophils from BALB/cJ mice appeared smaller and contained less cytoplasm than those from CBA/J mice. We conclude that strain differences in the number of tuberoinfundibular dopamine neurons are inversely related to the number of immunocytochemically demonstrable prolactin-containing cells in the anterior pituitary.