Penetrating neck injuries: analysis of experience from a Canadian trauma centre.

OBJECTIVE: To study the demographics and treatment outcome of penetrating neck injuries presenting to a major trauma centre in order to develop a treatment protocol. DESIGN: A case review. SETTING: A trauma centre at a tertiary care institution. PATIENTS: One hundred and thirty consecutive patients who had 134 neck wounds penetrating the platysma and presented to the trauma service between 1979 and 1997. INTERVENTION: Surgical exploration or observation alone. MAIN OUTCOME MEASURES: The location of injury, patient management, number of significant injuries, duration of hospital stay and outcome. RESULTS: Injuries were caused by stab wounds in 124 patients (95%) and gunshot wounds in 6 (5%). The location of injury was zone I (lower neck) in 20 cases (15%), zone II (midportion of the neck) in 108 (81%) and zone III (upper neck) in 5 (4%). The location was not recorded in 1 case. Fifty patients were managed by observation alone and 80 were managed surgically. Neck exploration in 48 asymptomatic patients was negative in 32 (67%). Significant injuries, including major vascular (12), nerve (13) and aerodigestive tract (19) injuries, were identified in 34 patients. Two of the 130 patients (1.5%) died of major vascular injuries. Seventy-six percent of significant injuries, including all zone II major vascular injuries, were symptomatic on presentation. The mean (and standard deviation) hospital stay for asymptomatic patients treated with observation alone and surgical exploration was similar (3.5 [6.02] versus 4.3 [5.46] days respectively, p = 0.575). Long-term disability, all neurologic in nature, was documented in 3 patients managed by observation alone and 6 patients managed by surgical exploration. CONCLUSIONS: Penetrating neck trauma, in particular stab wounds to zone II in asymptomatic patients, is associated with low morbidity and mortality. A selective management protocol with investigations directed by symptoms is the most appropriate approach for the patient population and resource base in this setting.

Physiological responses of the airway wall and lung in hyperresponsive pigs.

Airway hyperresponsiveness (AHR) might be driven by mechanisms inherent to the airway wall, and/or by factors arising from outside the airways. A porcine model of allergen-induced AHR was utilized to investigate physiological responses in intact airways in vitro and their contribution to responsiveness in vivo. Responsiveness to acetylcholine (ACh) was measured in eight ovalbumin (OA)-sensitized/challenged pigs (tests) and eight saline-challenged controls. In vivo responsiveness to ACh was determined from pulmonary resistance (RL). In vitro responsiveness to ACh was determined from airway pressure in isovolumic bronchial segments, after exposure via the adventitial or the luminal surface. Test pigs had lung (255+/-26% increase in RL, p<0.0001) and skin responses to OA, and AHR to ACh (p<0.0001). In vitro, test bronchi were less sensitive than controls to ACh applied to the airway adventitia (negative log of the ACh concentration producing half the maximum response (pD2)=4.18 and 4.58 respectively, p<0.01), but not the lumen. Test bronchi had an increased amount of smooth muscle normalized for airway size versus controls (p<0.05). Maximum responses to lumenal ACh in vitro showed a weak positive correlation with maximum changes to ACh in vivo (r=0.599, p=0.05). This study concludes that the effect of antigen challenge on bronchial responsiveness varies with the route of exposure to acetylcholine. In vitro responses to lumenal acetylcholine are increased despite a possible reduction in responsiveness of airway smooth muscle. Responsiveness of the bronchial wall only partially explains responsiveness of the lungs in vivo.

Pulmonary vascular congestion selectively potentiates airway responsiveness in piglets.

The influence of pulmonary vascular congestion on the response of the airways and lung tissue to low doses of inhaled methacholine (MCh) was studied by inflating a balloon catheter in the left atrium of the heart in six piglets, with an additional five piglets serving as control animals. Congestion alone resulted in small increased in baseline airway (Raw) (14.6 +/- 3.7%) and tissue (Rti) resistance (8. 1 +/- 6.5%). Low-dose inhaled MCh (0.3 mg/ml) increased Raw and Rti in the control group by 10.8 +/- 10.3% and 42.2 +/- 29.5%, respectively. The increase in Raw with MCh in the presence of vascular engorgement was significantly greater (67.8 +/- 18.9%) but the increase in Rti (38.1 +/- 13.2%) was similar to that seen in the control group. Morphometric measurements were performed on transverse sections of large and small airways from nine additional piglets (three congested only, three MCh only, and three congestion plus MCh). The thickness of the inner airway wall was similar in all groups. Compared with MCh only piglets, the thickness of the outer airway wall (between the outer border of the smooth muscle and the surrounding lung parenchyma) was increased (p < 0.05) in engorged only and engorged plus MCh piglets. Compared with MCh only and engorgement only, the amount of airway smooth muscle shortening was greater (p < 0.05) in all airway size groups in piglets that underwent engorgement plus MCh challenge. The results of this study demonstrate that pulmonary vascular engorgement, induced by increased left atrial pressure, selectively enhances the airway, but not the parenchymal, response to inhaled MCh. These changes are associated with increased thickness of the outer airway wall in response to vascular congestion, suggesting that uncoupling of the mechanical interdependence between the airway smooth muscle and the lung parenchyma may have occurred. Mechanical uncoupling may reduce the load opposing smooth muscle shortening resulting in increased airway narrowing in response to low doses of inhaled methacholine.

Assessment of the dynamic relationship between external diameter and lumen flow in isolated bronchi.

Histologic studies of large airways suggest that outer airway wall area increases during bronchoconstriction, which could influence the relationship between external diameter and lumen flow. Using isolated bronchi from pigs we simultaneously recorded external diameter using sonomicrometry, and lumen flow of liquid using an electromagnetic flowmeter to determine the relationship between the two. External diameter fell from 4.13+/-0.19 to 3.65+/-0.19 mm (11+/-3%, n = 5) during maximal electrical field stimulation (EFS), and flow decreased by 67+/-9%. External diameter plotted against lumen flow showed hysteresis between contraction and relaxation. External narrowing ceased towards the end of a stimulation period, but flow continued to decrease. This differed from predictions based on an assumption that the wall area does not change during contraction. Histologic sections of bronchi fixed after acetylcholine (ACh) challenge showed an increase in total wall area. These results illustrate dynamic wall movement during bronchoconstriction induced by EFS or acetylcholine.

Compliance and stability of the bronchial wall in a model of allergen-induced lung inflammation.

Airway wall remodeling in response to inflammation might alter load on airway smooth muscle and/or change airway wall stability. We therefore determined airway wall compliance and closing pressures in an animal model. Weanling pigs were sensitized to ovalbumin (OVA; ip and sc, n = 6) and were subsequently challenged three times with OVA aerosol. Control pigs received 0.9% NaCl (n = 4) in place of OVA aerosol. Bronchoconstriction in vivo was assessed from lung resistance and dynamic compliance. Semistatic airway compliance was recorded ex vivo in isolated segments of bronchus, after the final OVA aerosol or 0.9% NaCl challenge. Internally or externally applied pressure needed to close bronchial segments was determined in the absence or presence of carbachol (1 microM). Sensitized pig lungs exhibited immediate bronchoconstriction to OVA aerosol and also peribronchial accumulations of monocytes and granulocytes. Compliance was reduced in sensitized bronchi in vitro (P < 0.01), and closing pressures were increased (P < 0.05). In the presence of carbachol, closing pressures of control and sensitized bronchi were not different. We conclude that sensitization and/or inflammation increases airway load and airway stability.

Pulmonary inflammation without bronchial hyperresponsiveness in vivo or in vitro after sephadex instillation in pigs.

1. In rodent models, Sephadex produces pulmonary inflammation that may be associated with bronchial hyperresponsiveness. In the present study we examined whether Sephadex-induced inflammation altered airway narrowing in pigs. 2. Twenty millilitres of 10 mg/mL Sephadex suspension was instilled twice intratracheally into anaesthetized pigs (days 1 and 7 of a 9 day study). In vivo bronchial responsiveness was assessed from the effect of acetylcholine (ACh) aerosol on airways resistance and dynamic compliance before Sephadex instillation and on days 3, 5 and 9. Lung histology and in vitro bronchial responsiveness was assessed on day 9. In vitro responsiveness was assessed by measuring the reduction in flow through perfused 2 mm i.d. bronchial segments in response to ACh applied luminally and adventitially. 3. Sephadex produced a focal peribronchial granulomatous reaction characterized by the presence of macrophages, eosinophils, neutrophils and giant cells. Changes in airway resistance and lung compliance in response to ACh did not change over the study period. The response of perfused bronchial segments to luminally or adventitially applied ACh was also unaltered. 4. Sephadex-induced pulmonary inflammation does not alter airway narrowing in vitro nor bronchial hyperresponsiveness in vivo in the pig.

Concurrent measurement of smooth muscle shortening, lumen narrowing and flow to acetylcholine in large and small porcine bronchi.

Models of airway function indicate that responsiveness (flow reduction) to bronchoconstrictor provocation depends on airway smooth muscle shortening and airway wall morphology. The contribution of these factors to the responsiveness of central and peripheral bronchi was assessed. Lumen flow was recorded in porcine perfused small (2 min i.d.) and large bronchial segments (6 mm i.d.). Lumen diameter was recorded in the same airways after inserting an endoscope. Smooth muscle shortening, relative wall area (WAr), smooth muscle and cartilage thickness and mucosal folds were measured morphometrically. The effect of acetylcholine (ACh; 10(-6)-10(-1) M) on functional measurements was determined by curve fitting. Maximum muscle shortening was 30% in small and 19% in large bronchi (p<0.01) and lumen narrowing was 49% and 39%, respectively. High doses of ACh stopped flow in small bronchi, but produced a plateau in large bronchi. Small airways were 250-times more sensitive to ACh than large airways, for all measurements. Smooth muscle and cartilage thickness and numbers of mucosal folds were greater in large than in small bronchi (p< or =0.01). Lumen narrowing and flow reduction were greater than predicted on the basis of muscle shortening and WAr (p<0.05). The structure of airways from the two groups was qualitatively similar, but responses were markedly different. Greater narrowing and flow responses of small bronchi were directly associated with smooth muscle responsiveness in situ. The results suggest that in vivo changes in airway wall shape or dimensions, or luminal secretions, exert a significant effect on airway flow, particularly in the small airways.

Skeletal muscle and cardiovascular adaptations to exercise conditioning in older coronary patients.

BACKGROUND: Older coronary patients suffer from a low functional capacity and high rates of disability. Supervised exercise programs improve aerobic capacity in middle-aged coronary patients by improving both cardiac output and peripheral extraction of oxygen. Physiological adaptations to aerobic conditioning, however, have not been well studied in older coronary patients. METHODS AND RESULTS: The effect of a 3-month and a 1-year program of intense aerobic exercise was studied in 60 older coronary patients (mean age, 68 +/- 5 years) beginning 8 +/- 5 weeks after myocardial infarction or coronary bypass surgery. Outcome measures included peak aerobic capacity, cardiac output, arterio-venous oxygen difference, hyperemic calf blood flow, and skeletal muscle fiber morphometry, oxidative enzyme activity, and capillarity. Training results were compared with a sedentary, age- and diagnosis-matched control group (n = 10). Peak aerobic capacity increased in the intervention group at 3 months and at 1 year by 16% and 20%, respectively (both P < .01). Peak exercise cardiac output, hyperemic calf blood flow, and vascular conductance were unaffected by the conditioning protocol. At 3 and 12 months, arteriovenous oxygen difference at peak exercise was increased in the exercise group but not in control subjects. Histochemical analysis of skeletal muscle documented a 34% increase in capillary density and a 23% increase in succinate dehydrogenase activity after 3 months of conditioning (both P < .02). At 12 months, individual fiber area increased by 29% compared with baseline (P < .01). CONCLUSIONS: Older coronary patients successfully improve peak aerobic capacity after 3 and 12 months of supervised aerobic conditioning compared with control subjects. The mechanism of the increase in peak aerobic capacity is associated almost exclusively with peripheral skeletal muscle adaptations, with no discernible improvements in cardiac output or calf blood flow.

Intramural elastase injection increases responsiveness of isolated bronchial segments.

In cartilaginous bronchi, the smooth muscle is attached to the adventitial cartilage by a fibro-elastic matrix. In pigs, this matrix is stretched during muscle contraction so the inner airway wall reversibly uncouples from the outer wall. We hypothesized that inflammatory cell derived proteases may degrade this fibro-elastic matrix, increasing airway responsiveness. Airway responsiveness was determined from the sensitivity of perfused 2.0-3.5 mm id porcine bronchial segments to acetylcholine (ACh 10(-6)-10(-2)M) and from airway lumen narrowing imaged directly using a fibre-optic endoscope and video camera. Elastase (3 microliters, 1% solution) injected between the cartilage and the smooth muscle doubled sensitivity to ACh (P < 0.001) in perfused segments. Maximal airway narrowing to 10(-2) ACh was also increased from 54% to 60% (P < 0.05). Smooth muscle contraction, recorded isometrically, was not increased by elastase. We conclude that proteases may increase airway wall uncoupling in vitro, possibly by reducing the wall load, and thereby increasing responsiveness.

Effect of diameter on force generation and responsiveness of bronchial segments and rings.

In this study, isovolumic bronchial segments and bronchial rings were used to investigate the influence of airway diameter on smooth muscle force generation and acetylcholine responsiveness. Segments with internal diameters ranging from 1.0-6.0 mm were obtained from the mainstem bronchus of eight pigs. Responses to increasing acetylcholine concentrations were quantified in segments by intralumenal pressure (cmH2O), and in rings by tension (g.cm-1). The negative log of the concentration producing half the maximal effect (EC50) (i.e. pD2) to acetylcholine was calculated for each segment and ring. Ring tension was used to calculate a theoretical lumen pressure for each ring, and this, along with the pD2, was compared with values obtained from segments of the same diameter. Intermediate-sized segments produced significantly greater intralumenal pressures than did large or small segments. Small segments were 160 times more sensitive to acetylcholine than large segments. In contrast to the segments, bronchial rings showed no effect of size on acetylcholine sensitivity. Theoretical ring lumen pressures matched those measured for large and intermediate segments, but not for small segments. The different behaviour of bronchial segments and rings obtained from the same sized airway suggests that the three-dimensional architecture of the airway is an important factor in determining behaviour, particularly in small airways.

Uncoupling in the wall of the cartilaginous bronchus of the pig produced by smooth muscle contraction.

Studies in small non-cartilaginous airways suggest that the cross sectional area of the airway wall (comprising the smooth muscle and mucosa) is unaltered during the contraction-relaxation cycle produced by bronchial provocation. In the present study we examined whether the wall area of large cartilaginous bronchi remained constant during bronchoconstriction produced by acetylcholine (ACh, 10(-4)-10(-2)M), and if not the effect of this on the narrowing of the bronchial lumen. Narrowing of the lumen and adventitia of bronchial segments, 3.6 mm id from pigs, was simultaneously recorded using endoscopy and video imaging of the airway lumen. Concurrently, the shortening of the smooth muscle was estimated morphometrically from the same bronchi fixed during muscle contraction. In individual bronchi, ACh produced from 5 to 60% shortening of the smooth muscle, which caused up to 64% narrowing of the bronchial lumen, but only approximately 10% narrowing of the adventitia. Lumen narrowing was greater than predicted. Morphological assessment showed a doubling of the area between the smooth muscle and the cartilage, in response to maximum smooth muscle contraction by ACh. In contrast the area of the smooth muscle and mucosa did not change. Similar changes in bronchial morphology were produced in whole lung slices, incubated in ACh or histamine. We conclude that the inner airway wall uncouples from the outer wall during muscle contraction and that this increases the narrowing of the airway lumen relative to the adventitia.

Epithelial modulation of neonatal and fetal porcine bronchial contractile responses.

We tested the hypothesis that bronchial epithelium of newborn and fetal pigs exerts an inhibitory effect on bronchial contractile function. In vitro studies were performed on 13 isolated bronchial segments from seven neonatal pigs (12 h to 4 d old) and on 9 bronchial segments from five late-term pig fetuses (105 d gestation, term = 115 d). This preparation keeps the lumen of the airway physiologically intact and separate from the serosal aspect. Stem bronchi of the right and left lung were mounted horizontally at 6 cm H2O in a chamber containing oxygenated Kreb's solution. One bronchus was intact while the other had the epithelium removed with a cotton-tipped applicator soaked in Kreb's solution. Removal of epithelium was confirmed histologically. The lumen pressure of the mounted bronchi was measured at constant volume after the luminal application of acetylcholine (ACh) or K2SO4 (80 mM/L in place of NaCl), after serosal applications of these two substances at the peak of the luminal response, and after serosal application of ACh alone (newborn only). ACh (1, 10, and 100 microM) in the lumen of intact airways of neonatal pigs caused contractions of 0.1 +/- 0.07 (SEM), 0.4 +/- 0.14, and 0.9 +/- 0.18 cm H2O, respectively; in airways denuded of epithelium, ACh caused contractions of 3.9 +/- 1.1, 15.5 +/- 2.94, and 2.95 +/- 4.97 cm H2O (p < 0.001 versus intact airways). Luminal contractions were 2.9 +/- 2.2%, 2.6 +/- 0.9%, and 2.8 +/- 0.7% of the luminal+serosal values for intact segments, as compared with 65.5 +/- 4.6%, 58.8 +/- 7.7%, and 75.1 +/- 6.2% for denuded segments (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Which nutritional measurements assess protein-energy nutritional status in patients receiving home parenteral nutrition?

Weight, midarm circumference, triceps skinfold thickness, arm muscle circumference, albumin, prealbumin, transferrin and total lymphocyte count were measured at each outpatient visit in patients reveiving home parenteral nutrition from September 1987 to November 1991. Each nutritional variable was analysed for individuals and for the whole group. Group data were expressed using the actual values obtained and successive differences (the change between clinic attendances). Nutritional variables were evaluated using a correlation matrix. Identical analysis of individual and group data demonstrates that laboratory investigations are of little value in the assessment of nutritional status in patients receiving home parenteral nutrition. Anthropometry detected changes in body weight secondary to changes in muscle and/or fat in 80% of patients. Pooling anthropometric data distors the relationship between variables owing to inter-individual variability when actual values are used. The method of successive differences is the preferred method of analysis for group anthropometric data.

Cardiovascular responses to exogenous platelet-activating factor (PAF) in anesthetized ponies, and the effects of a PAF antagonist, WEB 2086.

The effects of exogenous platelet-activating factor (PAF) were determined in anesthetized ponies. Administration of PAF induced a decrease in cardiac index that resulted in systemic hypotension. This was followed by tachycardia, hypertension, and a return of cardiac index to baseline. Pulmonary arterial pressure increased markedly because of pulmonary vasoconstriction. Exogenous PAF also caused leukopenia and thrombocytopenia. The specific PAF receptor antagonist (WEB 2086) blocked all PAF-induced changes. Flunixin meglumine, a cyclooxygenase inhibitor, abolished the pulmonary hypertension and tachycardia, and attenuated the systemic hypotension but did not change the PAF-induced peripheral cellular changes. The PAF antagonist also inhibited platelet aggregation induced by PAF in vitro. The PAF-induced changes are similar to those reported after endotoxin exposure in horses.

Effects of xylazine on airway function in ponies with recurrent airway obstruction.

The effect of IV administration of the alpha 2-adrenoceptor agonist xylazine hydrochloride (0.5 mg/kg of body weight) was examined in ponies with recurrent obstructive pulmonary disease, commonly called heaves. Six ponies with the disease (principals) were studied during clinical remission and during an acute attack of airway obstruction precipitated by stabling and feeding of dusty hay. Six control ponies were also studied. In principal ponies with airway obstruction, xylazine administration significantly (P < 0.05) decreased pulmonary resistance and increased dynamic compliance, but did not affect PaO2 or PaCO2. The alpha 2-antagonist yohimbine blocked the pulmonary effects of xylazine. Administration of saline solution was without effect in both groups of ponies at all periods and xylazine did not have effect in controls or in principals in clinical remission.

Decreased airway mucosal prostaglandin E2 production during airway obstruction in an animal model of asthma.

Heaves is a respiratory disorder of horses and ponies characterized by bouts of acute airway obstruction and airway hyperresponsiveness. We measured prostaglandin E2 (PGE2) and 15-hydroxyeicosatetraenoic acid (15-HETE) production in vitro in tracheal epithelium obtained from six affected horses at the time of acute airway obstruction as compared with six matched control horses. Strips of epithelium and subepithelial tissue were prepared and stimulated with A23187, histamine, and bradykinin. The PGE2 and 15-HETE in media from strips was quantitated by radioimmunoassay. 15-HETE above the limits of accurate detection was found in epithelial strips of only two principal animals and in none of the control horses, and the amount of 15-HETE was not increased when strips were stimulated. Epithelial strips from affected horses tended to produce less PGE2 than did strips from control horses, and there was a significant correlation between epithelial PGE2 production and the time taken for affected animals to develop airway obstruction. Subepithelial tissue strips from control horses produced significantly more PGE2 in response to A23187 and bradykinin than did strips from affected horses. We conclude that equine tracheal epithelium is not a significant source of 15-HETE. Airway mucosal PGE2 production is reduced in horses with heaves, which suggests that a relative decrease in this bronchorelaxant substance may be a factor in the pathogenesis of this model of asthma.

Increased pulmonary production of immunoreactive 15-hydroxyeicosatetraenoic acid in an animal model of asthma.

Airway obstruction and hyperreactivity are characteristics of human asthma and of "heaves," a naturally occurring respiratory disorder of horses and ponies. We measured pulmonary function and plasma immunoreactive 15-hydroxyeicosatetraenoic acid (i15-HETE) concentrations in simultaneously collected carotid artery and right ventricle blood samples in five affected ponies and their age- and gender-matched control ponies. Measurements and sampling were performed before (Period A), during (Period B), and following recovery from (Period C) acute airway obstruction precipitated by housing ponies in a barn and exposing them to hay dust. Pulmonary resistance increased significantly, and dynamic compliance and PaO2 decreased significantly in affected ponies at Period B. Plasma i15-HETE concentrations were greater in carotid artery samples compared with right ventricle samples in affected ponies at each measurement period, suggesting that the lung was a source of i15-HETE. Carotid artery i15-HETE concentrations were significantly greater in affected ponies than in control ponies and increased at Period B. There was a significant negative correlation between changes in plasma i15-HETE and changes in dynamic compliance between measurement Periods A and B. We conclude that the lung is a source of i15-HETE in ponies with heaves, that these ponies produce greater quantities of i15-HETE than control ponies, and that exposing affected ponies to a barn environment produces acute airway obstruction and increased plasma concentrations of i15-HETE.

Exercise-induced pulmonary hemorrhage in horses with experimentally induced allergic lung disease.

The lungs of sensitized horses were exposed to aerosolized ovalbumin. Some horses (n = 4) were given ovalbumin in 1 lung only, whereas in others (n = 7), ovalbumin or vehicle were inoculated in the cranial, ventral, and caudal regions of the caudal lung lobe. Horses were exercised 5 hours after ovalbumin exposure. Immediately before exercise, endoscopy failed to reveal any abnormality. After exercise, endoscopic examination of horses subjected to unilateral ovalbumin exposure revealed extensive blood in airways leading to the exposed lung in all horses. Blood was not observed in the airways leading to the control lung. Mean (+/- SEM) minimum volume of the exposed and control lungs was 9.5 +/- 1.5 and 5.5 +/- 1.6 L, respectively; this difference was statistically significant (P less than 0.05). Bronchoscopy of horses subjected to regional ovalbumin or vehicle exposure and exercise revealed a small amount of blood-tinged fluid in the bronchi serving the regions of the lung inoculated with ovalbumin. Minimum volumes of such regions were not significantly different from one another. However, their minimum volume was significantly (P less than 0.05) larger than that of vehicle-inoculated regions. Gross and histologic examination confirmed inflammation and hemorrhage in the ovalbumin-exposed, but not the control lungs or lung regions. Thus, exercise can cause blood from an injured region of lung to appear in the larger airways. Regional differences in lung structure and function do not influence the appearance of blood in the airways.

Epithelial strips: an alternative technique for examining arachidonate metabolism in equine tracheal epithelium.

We have developed an alternative method for examining equine tracheal epithelial arachidonic acid (AA) metabolism that utilizes strips of pseudostratified columnar epithelium attached to a layer of elastic tissue 80 to 130 microns thick. We compared the responses of this preparation with those of enzymatically dispersed suspensions of tracheal epithelium obtained from the same animal. Strips incubated with [3H]AA incorporated 40.8 +/- 3.6% of added radioactivity and released 2.55 +/- 0.23% of incorporated radioactivity when stimulated with 5 microM A23187. Values for the cell suspension were 59.6 +/- 1.6% and 1.90 +/- 0.08%, respectively. Stimulation with 50 microM histamine or bradykinin resulted in significant release of free [3H]AA only from the strips. High-performance liquid chromatography radioactivity profiles of eicosanoids released following stimulation with 5 microM A23187 demonstrated peaks that coeluted with free AA, prostaglandin (PG) E2, and PGF2 alpha for the strips, and free AA, leukotriene B4, and 5-HETE for the cell suspensions. The absence of PGE2 production by cell suspensions was confirmed by assaying immunoreactive PGE2 in supernatants from unlabeled strips and suspensions stimulated with 5 microM A23187. Epithelial strips produced 10.3 +/- 1.3 ng PGE2/ml supernatant, whereas 5 x 10(6) cells in suspension produced less than 100 pg/ml. Despite the lack of PG production by the cell suspensions, immunocytochemical staining with an anti-PGH synthase antibody demonstrated the presence of PGH synthase in epithelial cells of both preparations. These data indicate that, in contrast to epithelial cell suspensions, epithelial strips synthesize cyclooxygenase metabolites and respond to peptide agonists.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of bovine respiratory syncytial virus on airway function in neonatal calves.

Respiratory syncytial virus (RSV) infection causes severe lower respiratory tract disease in infants and calves. Neonatal respiratory tract infection in children often produces persistent changes in lung function. The specific objective of this study was to determine whether neonatal calves have transient or persistent alterations in pulmonary function and airway reactivity following RSV infection. Six 2- to 3-day-old Holstein bull calves were inoculated with 10 ml of bovine respiratory syncytial virus (BRSV) inoculum (10(2.7) to 10(3.8) cell culture infective doses/ml) intranasally and 10 ml of BRSV inoculum (10(4.8) to 10(5.9) cell culture infective doses/ml) intratracheally for 4 consecutive days, and 5 other calves were sham-inoculated. Prior to inoculation (day 0) and on days 4, 14, and 30 after the last inoculation, body weight (kg), dynamic compliance (Cdyn), pulmonary resistance (RL), and 2 indices of airway reactivity (effective dose [ED] 65Cdyn and ED200RL) were measured. Control calves gained weight progressively throughout the study, whereas RSV-inoculated calves failed to gain weight for 14 days, but equaled control calf weight by 30 days after inoculation. The Cdyn of control calves increased significantly by 30 days, but did not in the RSV-infected calves. Pulmonary resistance was increased significantly at 4, 14, and 30 days, but was unaffected by sham inoculation. The ED65Cdyn and ED200RL indicated an age-dependent increase in reactivity to histamine and an increase in responsiveness in the infected group beginning at 14 days and persisting until the end of the study.(ABSTRACT TRUNCATED AT 250 WORDS)