T cells expressing specific V beta elements regulate immunoglobulin E production and airways responsiveness in vivo.

The role of T cells expressing specific V beta elements was examined in the regulation of allergen-specific immunoglobulin (Ig)E production and airways responsiveness (AR). In BALB/c mice, inhalation of the allergen ovalbumin (OVA) induced an IgE anti-OVA response, immediate cutaneous reactivity, and increased AR. These results were associated with an expansion of V beta 8.1/8.2 T cells in local draining lymph nodes of the airways and the lung. Transfer of V beta 8.1/8.2 T cells from sensitized mice stimulated an IgE anti-OVA response, immediate cutaneous hypersensitivity, and increased AR in naive syngeneic recipients. In contrast, OVA-reactive V beta 2 T cells inhibited these effects. These data demonstrate for the first time that T cells with different V beta specificities play a critical role in the in vivo regulation of allergen-specific IgE production and AR.

Development of eosinophilic airway inflammation and airway hyperresponsiveness in mast cell-deficient mice.

Mast cells are the main effector cells of immediate hypersensitivity and anaphylaxis. Their role in the development of allergen-induced airway hyperresponsiveness (AHR) is controversial and based on indirect evidence. To address these issues, mast cell-deficient mice (W/W v) and their congenic littermates were sensitized to ovalbumin (OVA) by intraperitoneal injection and subsequently challenged with OVA via the airways. Comparison of OVA-specific immunoglobulin E (IgE) levels in the serum and numbers of eosinophils in bronchoalveolar lavage fluid or lung digests showed no differences between the two groups of mice. Further, measurements of airway resistance and dynamic compliance at baseline and after inhalation of methacholine were similar. These data indicate that mast cells or IgE-mast cell activation is not required for the development of eosinophilic inflammation and AHR in mice sensitized to allergen via the intraperitoneal route and challenged via the airways.

Requirement for CD8+ T cells in the development of airway hyperresponsiveness in a marine model of airway sensitization.

To study the role of CD8+ T cells in allergic sensitization, we examined the effects of in vivo depletion of CD8+ T cells prior to sensitization on IgE production, immediate type cutaneous hypersensitivity and development of altered airway responsiveness. BALB/c mice were thymectomized and treated with anti-CD8 antibody resulting in depletion of CD8+ T cells (<1%) in spleen and lymphoid tissues. In these mice, sensitization to ovalbumin (OVA) via the airways still resulted in IgE anti-OVA responses and immediate cutaneous reactions to OVA, but the animals were unable to develop airway hyperresponsiveness, eosinophil infiltration of the lung parenchyma, or IL-5 production in the local lymph nodes of the airway. Transfer of CD8+ T cells from naive animals during sensitization (on day 8 of the 10-d protocol) fully restored the ability to develop airway hyperresponsiveness and this was accompanied by IL-5 production and eosinophil accumulation in the lung. These data indicate a critical role for CD8+ T cells in the production of IL-5 and the development of altered airway responsiveness after antigen sensitization through the airways.

Metabolism of 2,4',5-trichlorobiphenyl by the mercapturic acid pathway.

Carbon-14-labeled 2,4',5-trichlorobiphenyl was found to be metabolized by the mercapturic acid pathway to metabolites that are excreted in bile. About 57 percent of the carbon-14 was excreted in the bile; 30 to 35 percent was present as mercapturic acid pathway metabolites. Mercapturic acid was also isolated from the urine (0.3 percent of the dose).

Absorption, distribution, metabolism and excretion (ADME) study with 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE-154) in male Sprague-Dawley rats.

A metabolism study of orally administered 2,2',4,4',5,6'-hexabromodiphenyl ether (BDE-154; 11.3 micromoles kg(-1)) was conducted in conventional and bile duct-cannulated male Sprague-Dawley rats. In conventional rats, approximately 31% of the radiolabelled dose was retained at 72 h, and lipophilic tissues were the preferred sites for disposition. Urinary excretion of BDE-154 was very low (1.0%), and parent compound was detected. Cumulative biliary excretion was 1.3%, and glutathione conjugates were suggested. Over 62% of the dose in conventional male rats was excreted in faeces, and was composed of parent compound (7.3%), free metabolites (13.1%), and covalently bound residues (41.4%). Faecal metabolites characterized by gas chromatography/mass spectrometry included multiple isomers of monohydroxylated hexa-/penta-/tetrabromodiphenyl ethers, and di-hydroxylated hexa/pentabromodiphenyl ethers. The adipose tissue 14C was extractable BDE-154, but 40% of liver 14C was bound to macromolecules. The study demonstrated the importance of performing individual polybrominated diphenyl ether (PBDE) metabolism studies to understand fully PBDE pharmacokinetics.

In vivo clearance and tissue distribution of C5a and C5a des arginine complement fragments in rabbits.

We have previously shown a marked difference in the inflammatory response to human C5a or C5a des arginine (Arg) instilled in rabbit lungs. These studies raised the question of where C5a and C5a des Arg are processes in vivo and what role neutrophils may play in the tissue distribution of these two mediators. After intravenous injection of purified, biologically active 125I-C5a or 125I-C5a des Arg, adult rabbits were serially bled and then killed at various time intervals. Although greater than 50% of the injected radioactivity was cleared from the circulation within 2 min for both mediators, C5a des Arg persisted in the circulation longer than C5a. C5a instillation caused an acute neutropenia, whereas C5a des Arg caused a less severe and more prolonged neutropenia, preceding a neutrophilic response observed with both mediators. Clearance of the mediators was primarily seen in the highly vascularized organs: the lung, spleen, liver, and kidney. A time-dependent accumulation was seen initially in the lung, followed by the spleen, liver, and kidney. Histologic examination showed a marked increase in the number of neutrophils within the lung and spleen. Depletion of circulating neutrophils by nitrogen mustard pretreatment of rabbits showed no change in the amount of labeled mediator bound in the lung, whereas splenic accumulation was dependent on the presence of neutrophils. These results indicate that C5a and C5a des Arg are rapidly removed from the circulation by specific accumulation in vascularized tissues. Clearance by the lung was not affected by neutrophil depletion, whereas clearance by the spleen was dependent on neutrophils. These experiments further suggest there are neutrophil-dependent and neutrophil-independent mechanisms involved in the removal of C5a and C5a des Arg from the circulation and that binding of C5 fragments in the pulmonary vasculature may precede and then induce neutrophil sequestration.

Pulmonary response of fifth component of complement-sufficient and -deficient mice to hyperoxia.

The fifth component of complement, C5, can form fragments that cause neutrophil chemotaxis, oxygen radical production, and lysosomal enzyme release. The purpose of this study was to determine if C5 and these fragments contribute to the inflammation seen in pulmonary oxygen toxicity as defined by histology and analysis of bronchoalveolar lavage fluid (BALF). In addition, the role of C5 in producing mortality in the animals was addressed. Pairs of C5 deficient (C5-) and C5 sufficient (C5+) mice, 6 mo or older, were placed in a chamber and challenged with 95% oxygen at ambient pressure. A significant difference in mortality was observed after 200 h of exposure, i.e., 90% mortality in C5+ mice vs. 25% mortality in C5- mice (P less than 0.001). This difference in mortality was not seen when C5- mice were transfused with plasma that contained C5 derived from C5+ mice. Morphometric analysis of histologic sections with light microscopy revealed earlier pathologic changes in C5+ mice that was characterized by increased cellularity due in part to neutrophil influx into the alveolar-capillary wall. Transmission electron microscopy also confirmed an earlier inflammatory response in the C5+ mice with evidence of injury to alveolar epithelial cells, interstitial edema, and an increase in the cellular component of the interstitium. Analysis of BALF also demonstrated earlier abnormalities in C5+ mice, which included a significantly greater percentage of neutrophils in the C5+ mice at 117 h. Similar studies in younger mice of these strains again showed earlier neutrophil accumulation in C5+ mice, but the time course of the injury was more protracted. This study shows that the presence of C5 is associated with a greater mortality and an earlier influx of neutrophils into murine lungs. However, in the absence of C5, neutrophils will still immigrate into the lung and hyperoxic damage will occur at a later time point, which demonstrates the inherent redundancy of the inflammatory process.

Airway response to electrical field stimulation in sensitized inbred mice. Passive transfer of increased responsiveness with peribronchial lymph nodes.

We have examined the effects of repeated exposure to antigen on airway responses to cholinergic stimulation in two inbred strains of mice that are similar in underlying cholinergic airway responsiveness, yet differ in their ability to produce IgE. Both BALB/c and SJL/J mice were repeatedly exposed to ovalbumin by inhalation for a 10-d period. While the BALB/c mice developed IgE antibody to this allergen, the SJL/J strain failed to mount an appreciable IgE response. In vitro assessments of the response of tracheal smooth muscle from saline exposed mice (controls) of both strains demonstrated responses to both methacholine and electrical field stimulation that were not significantly different between the strains. Following exposure to ovalbumin, the BALB/c strain developed a significant increase in their response to electrical field stimulation, while their response to methacholine was unaltered. In contrast, the in vitro responsiveness to these stimuli did not increase in SJL/J mice following similar exposure to inhaled nebulized ovalbumin. The passive transfer of cells from the peribronchial lymph nodes of ovalbumin-sensitized BALB/c mice into syngeneic nonimmune mice also led to increases in responsiveness of tracheal smooth muscle to electrical field stimulation. In contrast, transfer of cells from nonsensitized mice did not alter responsiveness. These results suggest that murine species capable of developing an IgE response to allergen also develop alterations in the neural control of their airways. Further, this alteration appears to be lymphocyte dependent, in that cells found within peribronchial lymph nodes following allergen exposure are capable of transferring this increase in responsiveness to nonimmune mice.

Passive transfer of immediate hypersensitivity and airway hyperresponsiveness by allergen-specific immunoglobulin (Ig) E and IgG1 in mice.

In a proportion of atopic asthmatics, exposure to a relevant antigen is followed by chronic inflammation in the airways leading to altered airway responsiveness (AR). However, the mechanisms underlying the development of airway hyperresponsiveness still remain unclear. To elucidate the relationship between IgE-mediated reactions and airway hyperresponsiveness, a murine model of passive sensitization and airway challenge with ovalbumin (OVA) was developed using anti-OVA IgE and IgG antibodies from murine B cell hybridomas. Passive sensitization by intravenous injection of anti-OVA IgE resulted in immediate cutaneous hypersensitivity and, after airway challenge with OVA on two consecutive days, increased AR in BALB/c and SJL mice. Increased numbers of eosinophils were observed in bronchoalveolar lavage fluid, in cells extracted from the lungs, and in the peribronchial areas of BALB/c mice passively sensitized with IgE and challenged through the airways compared with nonsensitized mice. Eosinophil peroxidase activity was also elevated in lung tissue from these mice. Passive sensitization with anti-OVA IgG1 but not IgG2a or IgG3 was similarly associated with development of skin test reactivity and increased AR after airway challenge, accompanied by an increase in eosinophils in bronchoalveolar lavage fluid. These data suggest that IgE/IgG1-mediated reactions together with local challenge with antigen can result in allergic inflammation resulting in altered airway function.

Additive effect of intravascular complement activation and brief episodes of hypoxia in producing increased permeability in the rabbit lung.

Systemic complement activation with intravascularly administered cobra venom factor (CVF) or infusion of either zymosan-activated rabbit plasma or a fifth component of complement fragment with anaphylatoxin activity in the rabbit have not caused significant increases in bronchoalveolar lavage albumin in rabbits (Webster, R. O., G. L. Larsen, B. C. Mitchell, A. J. Goins, and P. M. Henson. 1982. Am. Rev. Respir. Dis. 125:335-340). To assess if another stimulus (hypoxia) acting in concert with complement activation can produce significant lung injury, rabbits were challenged with CVF alone, 10 min of 12% oxygen alone, or CVF followed by a 10-min exposure to 12% oxygen. Either stimulus alone caused no significant changes in arterial oxygen, pulmonary resistance, or dynamic compliance during the 240 min of observation after either stimulus, and neither stimulus alone caused increased albumin accumulation in bronchoalveolar lavage over a 30-min period at the end of the experiment. However, the combination of insults significantly altered arterial oxygen, pulmonary resistance, and dynamic compliance while also increasing albumin and neutrophils recovered by lavage. The increase in lavage albumin did not appear to be due to hemodynamic events in that the pulmonary artery pressure increased acutely after CVF infusion and again during the hypoxic exposure, but was normal when albumin accumulation in the lung was measured. Neutrophil depletion with nitrogen mustard abolished all of these changes induced by CVF plus hypoxia. In addition, meclofenamate pretreatment and infusion during the 4-h study abolished the increases in lavage albumin and neutrophils as well as the increase in pulmonary artery pressure after CVF. Meclofenamate pretreatment did not, however, block accumulation of albumin in the lung (interstitium). We conclude that complement activation, as an isolated event, will not cause a significant increase in lavage albumin in this model. However, combining complement activation with an episode of hypoxia will lead to an increase in lavage albumin that is dependent on the presence of neutrophils for its expression. Meclofenamate treatment will prevent increases in lavage albumin and neutrophils while not preventing albumin accumulation in the lung (interstitium), suggesting a product of the cyclooxygenase pathway of arachidonic acid metabolism is needed to produce movement of albumin and/or neutrophils across the alveolar epithelium in this model.

Postneonatal circumcision: population profile.

Because postneonatal circumcision includes the risk of general anesthesia and costs more than elective neonatal circumcision, a retrospective study was performed to describe the population currently undergoing postneonatal circumcision and to identify the factors influencing decisions that lead to this procedure. A chart review and follow-up telephone survey were done to gather information concerning patients admitted for postneonatal circumcision to two Salt Lake City hospitals during a 2-year period. From the 135 patients eligible for analysis, two distinct groups emerged: the "sick" group (n = 52)--those who had neonatal complications, and the "well" group (n = 83)--those with no neonatal complications. The median age at circumcision was 5.5 months for the boys in the sick group and 35 months for the boys in the well group (P less than .001, Student's t test). During the neonatal period, 32% of families in the well group received anticircumcision advice from their primary care physician. The decision in favor of circumcision was made by two thirds of the families of sick infants before their sons were 6 weeks of age. Other surgery was performed concurrent with the circumcision in 44% of patients in the sick group and 24% of patients in the well group (P less than .0001, chi 2). Balanitis, phimosis, or a physician's recommendation were listed as the primary reason for post-neonatal circumcision by 50% of patents in the well group. Phimosis was listed by the surgeon as an indication for postneonatal circumcision in 65% of all patients' charts, although only 13% of parents listed phimosis as an indication for their children's circumcision.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of treatment of primary carcinoma of the lung. Analysis of 3,000 cases.

Three thousand patients with primary carcinoma of the lung entered in the Armed Forces Central Medical Registry are reported. Forty-one per cent had squamous cell, 28.5 per cent adenocarcinoma, 25.2 per cent small cell/undifferentiated, and 4.9 per cent miscellaneous cell types. When first seen, 71.1 per cent had no organ metastases and 50.6 per cent no lymph node metastases. Over-all survival rate was 18.2 per cent at 5 years and 14.5 per cent at 10 years. Survival following definitive resection, palliative resection, definitive radiation, palliative radiation, and chemotherapy was determined both in the presence of mediastinal nodal involvement and in the absence of mediatinal nodal involvement. Where resection for cure could be carried out, 5 year survival rates of 48.8 per cent were possible. The factors affecting this improved outlook in our military population are discussed and, in general, appear to be related to a ready accessibility of medical care and the necessity, because of global commitments, of establishing an early diagnosis. Cell type ecerted some influence on survival, but the major determinant appeared to be the absence of involved nodes at the time of the operation.

Pulmonary microvascular alterations and injury induced by complement fragments: synergistic effect of complement activation, neutrophil sequestration, and prostaglandins.

Fragments of C5 that are generated at, or administered to, extravascular sites in the pulmonary parenchyma induced neutrophil infiltration, edema, tissue damage, and a complete inflammatory response. Generation of C5 fragments within the vascular system induced leukocyte sequestration in the pulmonary vasculature, but without detectable increased vascular permeability or neutrophil migration. By contrast, the combination of short episode of hypoxemia with the intravascular C5 activation led significant increases in pulmonary vascular permeability, mild endothelial alterations, and emigration of neutrophils. Infusion of 10 micrograms PGE2 into animals in which intravascular complement had been activated produced changes in the lungs that were similar to, though less severe than, the combination of hypoxia and complement activation.

SP-induced contraction of airway smooth muscle in normal and allergen-sensitized rabbits: mechanism of action.

We studied the mechanisms involved in the airway smooth muscle (ASM) contraction to substance P (SP) in normal (control) and allergen-sensitized (immune) rabbits as well as immune rabbits exposed to allergen via the airways (immune challenged). Cumulative concentration-response curves to SP (1 x 10(-9) to 1 x 10(-4) M) were performed in ASM segments in the absence and presence of atropine (10(-5) M) in vitro. The maximal contractile response (g tension/g tissue) at 10(-4) M SP and ASM contractions at various concentrations of SP were expressed as means +/- SE. We found no difference in the contractile response to SP between control and immune animals. ASM segments obtained from immune-challenged rabbits were more responsive to SP. Atropine shifted to the right the concentration-response curves and decreased the maximal ASM contraction at 10(-4) M SP in all three groups; this effect, however, was greater in immune-challenged tissues. These findings demonstrate an increased contractile response to SP in immune-challenged animals mediated by a more pronounced facilitation of cholinergic neurotransmission. We conclude that the final ASM response to SP is the result of a complex interaction between direct effects on ASM and indirect effects through modulation of cholinergic neurotransmission.

Thromboembolic phenomena in patients with prosthetic aortic valves who did not receive anticoagulants.

Seventy-two patients with Starr-Edwards aortic prostheses of the 2300 series were followed for 1 to 73 months (average, 22 months) without receiving anticoagulants. Nine patients had clinical evidence of an embolic episode (12.5%). One of these patients died, and 5 were left with a significant residual neurological deficit. Two other patients had hemiparesis but recovered fully. Only 1 episode could be considered minor. The reported lower incidence of thromboembolism in patients receiving this prosthesis with adequate anticoagulation has now led us to reverse our previous position and recommend anticoagulation for patients receiving Starr-Edwards aortic prostheses.

Mediastinoscopy. Its application in central versus peripheral thoracic lesions.

In an attempt to ascertain the value of mediastinoscopy in peripheral lung lesions, records of 157 patients undergoing cervicomediastinal exploration (CME) at Wilford Hall USAF Medical Center were reviewed. Among patients with benign lesions, CME was positive in 90.6% of those who had central lesions and 58.3% of those with peripheral lesions. It was positive in all 7 patients who had peripheral lesions with associated mediastinal nodes on roentgenogram and negative in all 5 who had peripheral lesions without nodes. In the patients with malignant lesions, CME was positive in 72.9% of those who had central lesions and 58.1% of those with peripheral lesions. It was positive in 24 of 27 patients who had peripheral lesions with associated mediastinal nodes and negative in 15 of 16 patients with peripheral lesions without nodes. Although we recognize this to be a selected series, CME does appear to be valuable in patients with central lesions and peripheral lesions with mediastinal nodal involvement on roentgenogram. It does not appear to be as useful in those with peripheral lesions who do not have central nodal involvement.

Asthma in infants and small children.

The wheezy young child is a particularly challenging patient to treat. This article focuses on a diagnostic approach and some of the treatment issues peculiar to this age group. Specifically addressed are (1) the problem of differentiating asthma from wheezy bronchitis in babies and the clinical implications of this; (2) general concepts of treating babies in whom many commonly used drugs are not FDA approved; (3) inhalation therapy, especially the use of metered-dose inhalers with spacers; (4) the standard asthma drugs and their beneficial and adverse effects, with particular reference to inhaled steroids; and (5) the nonpharmacologic management of asthma. A brief discussion of long-term outcome is also included.

Mechanisms of cholinergic dysfunction in rabbits following recurrent aspiration of cow's milk.

Recurrent aspiration of cow's milk has been shown to alter neural control of airways in young rabbits (Gelfand et al., 1997). The purpose of this study was to define the mechanisms responsible for in vitro cholinergic hyperresponsiveness in this model. Beginning at 1 week of age, rabbits received either 0.5 mL/kg whole cow's milk or sterile saline intranasally while under light anesthesia. This was repeated each weekday for 2 weeks. At 8 weeks of age, rabbits were sacrificed. Portions of lungs underwent lavage with sterile saline. Tracheal smooth muscle (TSM) segments were also removed. Segments were assessed for acetylcholine (ACh) release by high-performance liquid chromatography ( HPLC) with electrochemical detection or acetylcholinesterase (AChE) kinetic activity by spectrophotometry. Substance P (SP), a neuropeptide that can increase ACh release from nerves, was also assessed using an enzyme immunoassay to define the content in lavage and TSM segments. Immunohistochemistry for SP within airways was also assessed. We found that recurrent aspiration of milk led to statistically significant alterations in many parameters. Acetylcholine release was significantly greater in segments of airways from rabbits that had aspirated cow's milk (27.5 +/- 1.7 vs. 20.1 +/- 1.6 pmol/min/g tissue) than saline. At the same time, AChE activity was less in the group that aspirated milk (8.7 +/- 0.4 vs. 10.2 +/- 0.5 nmol/min/mg protein) compared to saline. The amount of SP within both lavage as well as tissue homogenates was greater in the group that had aspirated the foreign protein (159.1 +/- 28.9 vs. 41.9 +/- 5.2 pmol/mg protein in lavage; 158.7 +/- 31.9 vs. 80.5 +/- 7.8 pmol/mg protein in tissues) than saline controls. While total cholinergic nerve density as assessed by choline acetyltransferase was not significantly different between groups, SP-positive immunoreactive nerves were easily identified in the group that aspirated cow's milk. This study suggests that cholinergic hyperresponsiveness caused by repeated aspiration of milk is due to several abnormalities, including prejunctional (increase in ACh release) as well as junctional (decrease in AChE) mechanisms within the airways. In addition, an upregulation of SP within airways is part of this process.

Decrease in the airways' nonadrenergic noncholinergic inhibitory system in allergen sensitized rabbits.

A decrease in the airways' nonadrenergic noncholinergic inhibitory (NANC-i) system is one of the mechanisms that may contribute to allergen-induced changes in neural control within airways. We measured the airways' neurally mediated contractile and relaxant (NANC-i) responses in tracheal segments and left mainstem bronchus (LMB) from normal (control), immune (ragweed sensitized), and immune challenged rabbits. Immune rabbits were sensitized to mixed ragweed extract through parenteral injections from birth, while the immune challenged group had an additional airway exposure to aerosolized ragweed 48 hours prior to the in vitro studies. Neurally mediated contractile responses to electrical field stimulation (EFS) were increased in the immune challenged group, with the increase most significant in tracheal smooth muscle at a stimulation frequency of 20 Hz. To assess NANC-i responses, airway smooth muscle (ASM) segments from these groups were placed in tissue baths containing atropine (10(-6) M) and propranolol (5 x 10(-6) M). After contraction of the tissue with neurokinin A (NKA, 10(-5) M), the NANC-i response to EFS at 20 Hz was measured and reported as the mean (+/- SEM) percent relaxation. No significant differences were seen in the contractile responses of ASM segments to NKA among the three groups. The tracheal segments showed a significantly different NANC-i relaxation response among all groups: in the control group, 29.1 +/- 3.7; in the immune group 15.8 +/- 2.3%; and in the immune challenged group, 2.1 +/- 4.2%.(ABSTRACT TRUNCATED AT 250 WORDS)

Legionella and Pneumocystis pneumonias in asthmatic children on high doses of systemic steroids.

Asthma is increasingly treated as an inflammatory disease with inhaled and/or systemic corticosteroids. We report 3 cases of unusual pneumonias associated with high doses of oral steroids. Two patients contracted Legionella pneumonia and one patient contracted Pneumocystis carinii pneumonia. With increasing usage, it is important for physicians to be aware of the possible infectious complications of high dose steroids. This report highlights the risk of corticosteroid treatment in asthma in predisposing to opportunistic infections that have not heretofore been readily associated with asthma.