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At least 595 records · Page 33Linked to original sources
PubMed1996

Compartmentalization of glucose utilization after intravenous vs. intratracheal challenge with LPS.

The rate of glucose utilization (Rg) of various tissues including lung and bronchoalveolar lavage (BAL) fluids cells was measured, using the 2-deoxyglucose technique in Sprague-Dawley rats 4 h after challenge with either 1 mg/kg intravenous or 0.3 mg/kg intratracheal lipopolysaccharide (LPS). After intravenous LPS, Rg increased in whole lung and nonrespiratory tissues, but was unaltered in BAL cells. After intratracheal LPS, the Rg of nonrespiratory tissues was unchanged, but the Rg of BAL cells increased from 3.7 +/- 0.3 to 71.5 +/- 16.0 nmol/min. This increase in the Rg of BAL cells was explained by a doubling of the macrophage specific Rg, by a 100-fold increase in polymorphonuclear leukocytes (PMN) number, and by a higher Rg in PMN than in macrophages. These results demonstrate that increased glucose utilization after intratracheal LPS is confined to the respiratory system and that intra-alveolar phagocytes participate in this increase.

Animals↗
PubMed1995

Furosemide pharmacokinetics following intratracheal instillation in the guinea pig.

Inhaled furosemide has been shown to attenuate bronchospasm in asthmatics and to increase lung compliance in infants with bronchopulmonary dysplasia (BPD). The reports involving BPD used a dose of 1 mg/kg and some have failed to show an effect with that dose. We determined the pharmacokinetics of furosemide administered directly to the airway in 7 young adult male guinea pigs who received intravenous and intratracheal doses of furosemide. Each animal received a 3 mg/kg i.v. bolus, 1, 3 and 6 mg/kg i.t. in 2 ml/kg normal saline and 3 mg/kg i.t. in 2 ml/kg bovine extract surfactant. Blood was sampled multiple times after each dose. The mean fraction of the intratracheal dose absorbed was 0.50-0.60 for all doses. Surfactant delayed the absorption of furosemide but did not alter the fraction absorbed.

Animals↗
PubMed1992

Lung mechanics and gas exchange during pressure-control ventilation in dogs. Augmentation of CO2 elimination by an intratracheal catheter.

Increased awareness of pressure-related injury to the alveolar-capillary interface has renewed interest in modes of ventilation that limit alveolar distention such as pressure-controlled ventilation (PCV). We examined respiratory system mechanics and gas exchange during PCV in six dogs. Our data conformed to the predictions of our single-compartment mathematical model of respiratory dynamics during PCV (J Appl Physiol 1989; 67:1081-92). For a fixed pressure (Pset) and inspiratory time fraction (Tl/Ttot) (15 cm H2O and 0.3, respectively), minute ventilation (VE) reached a well-defined plateau as frequency (f) increased from 10 to 50 breaths/min and tidal volume (VT) fell progressively. Concomitantly, the physiologic dead-space fraction (VD/VT) increased from 0.50 +/- 0.04 to 0.85 +/- 0.04, and arterial PCO2 (PaCO2) rose from 39 +/- 4 to 76 +/- 12 mm Hg. At a fixed combination of frequency, applied pressure, and Tl/Ttot (40 breaths/min, 15 cm H2O, and 0.3), VE did not change when we introduced fresh gas continuously from an intratracheal catheter. However, PaCO2 and VD/VT fell progressively as catheter flow increased from zero to 14 L/min (60 +/- 12 to 40 +/- 12 mm Hg and 0.83 +/- 0.03 to 0.25 +/- 0.14 mm Hg, respectively). We conclude that during PCV at a fixed Pset and Tl/Ttot increasing frequency caused VT to fall and VE to reach a plateau. Declining VT was associated with a rise in PaCO2 because of a subsequent fall in alveolar ventilation. Insufflating fresh gas by an intratracheal catheter increased alveolar ventilation and improved CO2 elimination by washing out the anatomic dead space.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

A new endotracheal tube for neonatal use.

A new endotracheal tube for neonatal use is described in which a 5FG pressure measuring catheter is attached to the convex surface of a conventional polyvinylchloride endotracheal tube. Using this modified endotracheal tube intratracheal pressure can be measured. Preliminary studies were undertaken in three infants. It was found that at high ventilatory rates (above 80/min) pressures measured within the trachea were different from those measured in the ventilator circuit.

Humans↗
PubMed1982

Subglottic stenosis after cricothyroidotomy.

Analysis of the case histories of 17 patients who developed subglottic obstruction following cricothyroidotomy shows that all 10 patients with chronic stenosis had acute laryngeal pathology at the time of initial operation. Seven patients were identified as having acute subglottic obstruction with granulation tissue. Although these patients were effectively managed by local means, ineffective management of intratracheal granulation tissue may convert a minor, temporary problem into a serious chronic obstruction. Cricothyroidotomy is appropriately used for prolonged airway access only in patients free of acute laryngeal pathology.

Adolescent↗
PubMedDate not supplied

Thromboxane receptor activation during bronchospasm induced by platelet-activating factor.

The involvement of thromboxane receptors in the responses to platelet-activating factor (PAF) was examined in anesthetized guinea pigs. The thromboxane receptor antagonist SQ 30,741 (1 mg/kg i.v.), aspirin (10 mg/kg i.v.), or vehicle was given 3 min before PAF (0.25 micrograms/kg i.v.). In vehicle-treated animals, PAF reduced dynamic lung compliance (Cdyn, -71 +/- 5%) and increased total airways resistance (Rlung, 497 +/- 108%) (N = 8). Aspirin and SQ 30,741 blocked these responses by greater than 95% (p less than 0.001). However when the PAF dose was increased to 0.5 micrograms/kg, neither drug treatment prevented bronchospasm (-73 +/- 9 and -59 +/- 4% in Cdyn, respectively; N = 5). An intratracheal aerosol of 0.01% PAF was given to other guinea pigs after SQ 30,741 (1 mg/kg i.v. or 0.1% aerosol) or vehicle. In vehicle-treated animals, vaporized PAF reduced Cdyn (-41 +/- 5%) and increased Rlung (72 +/- 16%) (N = 5) and SQ 30,741 (i.v. and intratracheal) did not affect the magnitude of these responses. Intravenous PAF, but not aerosolized PAF, also increased hematocrit (reduced only by aspirin) and decreased circulating platelets (antagonized by SQ 30,741) and leukocytes (unaffected by SQ 30,741 or aspirin). As a positive control, the PAF antagonist WEB 2086 (1 mg/kg i.v.) inhibited all responses to i.v. and intratracheal PAF. These data suggest that thromboxane receptor activation participates in some of the effects of blood borne PAF in vivo.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1993

Selective exclusion of the injured lung.

Intratracheal bleeding and intrapleural air leakage that are uncontrollable by conventional therapy are life-threatening in patients with blunt pulmonary trauma. Selective exclusion of the injured lung is the most effective treatment in such cases. Two hundred six consecutive patients over a 5-year period with blunt pulmonary trauma who survived 5 hours or more after arriving at the hospital were divided into three categories based on mode of treatment. In 190 (92%), intratracheal bleeding, intrapleural air leakage, and intrapleural bleeding were controllable by conventional treatment (class 1). In six (3%), intratracheal bleeding and intrapleural air leakage were controllable by selective pulmonary exclusion, and intrapleural bleeding was controllable by tube thoracostomy (class 2). In ten (5%), thoracotomy was required because of uncontrollable intratracheal bleeding or intrapleural air leakage, despite selective pulmonary exclusion, or intrapleural hemorrhage was not controllable by tube thoracostomy (class 3). Among the 16 patients with class 2 or 3 trauma, 14 survived.

Adolescent↗
PubMed1999

Advances in ventilatory support of the pediatric surgical patient.

Severe respiratory failure in newborn and pediatric patients is associated with significant morbidity and mortality. Basic science laboratory investigation has led to advances both in our understanding of ventilator-induced lung injury and in optimizing the supportive use of conventional ventilation strategies. Over the past few years, progress has been made in alternative therapies for ventilating both children and adults with severe respiratory failure. This review focuses on recent laboratory and clinical data detailing the techniques of permissive hypercapnia, high frequency oscillatory ventilation, inhaled nitric oxide, intratracheal pulmonary ventilation, and liquid ventilation. Some of these modalities are becoming commonplace, and others may have much to offer the clinician if their benefit is clearly demonstrated in future clinical trials.

Child↗
PubMedDate not supplied

[Quantitative patterns of a model of intratracheal administration in an experiment].

The distribution of 239PuO2 (241Am) and BeO (7BeO) within the lungs of rats and dogs after the intratracheal administration was found to follow a normal law. The amplitude of deposition variations reached 98 per cent of the amount administered. It is recommended to group the experimental animals by individual deposition estimates.

Americium↗
PubMed1996

Platelet-derived growth factor causes pulmonary cell proliferation and collagen deposition in vivo.

Platelet-derived growth factor (PDGF) is postulated to play a role in the pathophysiology of pulmonary fibrosis. Recombinant human PDGF-BB administered as a single intratracheal injection in rats causes an increase in peribronchial and perivascular stromal cells on days 2 and 3 after injection as evaluated by hematoxylin and eosin histology and 5-bromodeoxyuridine incorporation. Proliferation of bronchial epithelial cells and arterial smooth muscle cells, although not evident by routine histological examination alone, is detected on days 2 and 3 by increased 5-bromodeoxyuridine incorporation. A mild increase in 5-bromodeoxyuridine labeling is observed in peripheral alveolar parenchyma after injection of PDGF. The proliferative peribronchial and perivascular mesenchymal cells appear by light microscopic and ultrastructural criteria to be fibroblasts that are immunoreactive for vimentin but negative for alpha-smooth muscle actin and desmin. Daily intratracheal injection of PDGF-BB for 3 days causes a slightly more pronounced peribronchial and perivascular spindle cell proliferation accompanied by collagen deposition as evaluated by Masson's trichrome stain. PDGF-induced increases in cellularity and collagen resolve within 5 days after the last PDGF injection. In conclusion, intratracheal injection of PDGF-BB causes transient proliferation of pulmonary mesenchymal and epithelial cells accompanied by collagen deposition.

Actins↗
PubMed2000

Intratracheal administration to the lung enhances therapeutic benefit of an MBP peptide in the treatment of murine experimental autoimmune encephalomyelitis.

The treatment of autoimmune diseases by targeted down-regulation of autoantigen-specific cells has been accomplished by the administration of high doses of autoantigen. We performed direct comparisons between injection of myelin basic protein peptide and administration by several nonparenteral routes to determine whether route impacted benefit in the treatment of murine allergic encephalomyelitis, a model for multiple sclerosis. The range of effective peptide doses spanned over 1000-fold, and route of delivery played a major role in determining optimal dose. The oral route of administration was the least effective, requiring at least 50- to 100-fold more antigen than subcutaneous injection, which in turn required at least 10-fold more antigen than delivery of peptide to the lung using an intratracheal instillation. Intratracheal delivery was also considerably more effective than inhalation of peptide, and, unlike inhalation, resulted in obvious penetration of delivered material deep into the lung. The increase in therapeutic efficacy did not appear to result from slower systemic delivery of antigen. Accumulation of peptide on antigen presenting cells in the spleen and in the brain was less efficient using the intratracheal route of administration compared to subcutaneous injection, implicating a special role for the lung microenvironment in the induction of immune nonresponsiveness.

Administration, Inhalation↗
PubMedDate not supplied

Experimental aerogenic pulmonary berylliosis in rabbits.

The dynamics of pulmonary changes produced by a prolonged daily administration of 1 g per cent solution of BeSO4 in aerosols was pursued by current histopathological methods in periodically sacrificed rabbits. A progressive constitution of beryliosic granulomas involving intralobular and interlobular areas was observed. The epithelioids and giant cells were present in variable proportions. Concomitantly, a cellular thickening of alveolar walls and perivascular cuffs was noted, as well as an intercellular reticulin fibrillogenesis. The intratracheal three-fold administration of a 0.3 g per cent solution of BeSO4 induced a more rapid formation of berylliosic nodules with the same characters. The relation between the cell accumulation and reticulin fibrillogenesis was morphometrically analysed and statistically verified as pertinent correlated phenomena.

Aerosols↗
PubMed1997

Intratracheal instillation of a novel NO/nucleophile adduct selectively reduces pulmonary hypertension.

We examined the pulmonary and systemic hemodynamic effects of administering soluble nitric oxide (NO) donor compounds (NO/nucleophile adducts, i.e., NONOates) directly into the trachea of animals with experimentally induced pulmonary hypertension. Steady-state pulmonary hypertension was created by using the thromboxane agonist U-46619. Yorkshire pigs were randomly assigned to one of four groups: group 1, intratracheal saline (control; n = 8); group 2, intratracheal sodium nitroprusside (n = 6); group 3, intratracheal ethylputreanine NONOate (n = 6); and group 4, intratracheal 2-(dimethylamino)-ethylputreanine NONOate (DMAEP/NO; n = 6). Pulmonary and systemic hemodynamics were monitored after drug instillation. Group 4 had significant reductions in pulmonary vascular resistance index (PVRI) at all time points compared with steady state and compared with group 1 (P < 0.05), whereas systemic vascular resistance index did not change. The mean change in mean pulmonary arterial pressure in group 4 was -33.1 +/- 1.2% compared with +6.4 +/- 1.3% in group 1 (P < 0.001), and the mean change in mean arterial pressure was -9.3 +/- 0.7% compared with a control value of -0.9 +/- 0.5% (P < 0.05). Groups 2 and 3 had significant decreases in both PVRI and systemic vascular resistance index compared with steady state and with group 1. In conclusion, intratracheal instillation of a polar-charged tertiary amine NONOate DMAEP/NO results in the selective reduction of PVRI. Intermittent intratracheal instillation of selective NONOates may be an alternative to continuously inhaled NO in the treatment of pulmonary hypertension.

Amino Acids, Diamino↗
PubMedDate not supplied

Intratracheal injection of crocidolite asbestos depresses the secretion of tumor necrosis factor by pleural leukocytes in vitro.

Tumor necrosis factor (TNF) is a cytokine released predominantly by monocytes/macrophages that has been shown to modulate a variety of different immune and metabolic functions. To understand the regulatory mechanisms of TNF in governing responses in the pleural cavity following deposition of fibrous dust in the airspace of the lung, we studied the capability of leukocytes, lavaged from the pleural cavity, to release TNF in culture. TNF production by lavaged pleural leukocytes was measured using the L-929 TNF-sensitive cell line, after intratracheal instillation of crocidolite asbestos. A high level of TNF activity was found in the supernatants of normal, unstimulated pleural leukocytes; the addition of 100 ng/ml lipopolysaccharide to the culture increased the activity up to threefold. Following intratracheal instillation of 5 mg crocidolite asbestos, the pleural leukocytes secreted less TNF than the control. With increasing mass of intratracheally instilled asbestos, there was a dose-dependent reduction in TNF release. Changes in the population of the pleural leukocytes or their number could not be related to variation in TNF activity. These results suggest that exposure of rat lungs to crocidolite asbestos by intratracheal instillation affects the response of pleural leukocytes without causing changes in the population. Such changes in the bronchoalveolar space may be related to the pleural pathology found in asbestos-exposed individuals.

Animals↗
PubMed2005

Pulmonary exposure to diesel exhaust particles induces airway inflammation and cytokine expression in NC/Nga mice.

Although several studies have reported that diesel exhaust particles (DEP) affect cardiorespiratory health in animals and humans, the effect of DEP on animal models with spontaneous allergic disorders has been far less intensively studied. The Nc/Nga mouse is known to be a typical animal model for human atopic dermatitis (AD). In the present study, we investigated the effects of repeated pulmonary exposure to DEP on airway inflammation and cytokine expression in NC/Nga mice. The animals were randomized into two experimental groups that received vehicle or DEP by intratracheal instillation weekly for six weeks. Cellular profiles of bronchoalveolar lavage (BAL) fluid and expressions of cytokines and chemokines in both the BAL fluid and lung tissues were evaluated 24 h after the last instillation. The DEP challenge produced an increase in the numbers of total cells, neutrophils, and mononuclear cells in BAL fluid as compared to the vehicle challenge (P<0.01). DEP exposure significantly induced the lung expressions of interleukin (IL)-4, keratinocyte chemoattractant (KC), and macrophage inflammatory protein (MIP)-1alpha when compared to the vehicle challenge. These results indicate that intratracheal exposure to DEP induces the recruitment of inflammatory cells, at least partially, through the local expression of IL-4 and chemokines in NC/Nga mice.

Animals↗
PubMed1998

[Routes of administration of drugs for severe acute asthma].

Beta2-mimetics represent the primary treatment for acute severe asthma. Their route of administration are nebulizer inhalation and inhalation chamber, or direct intratracheal route in patients receiving artificial ventilation. The subcutaneous route remains useful while awaiting implementation of nebulizer routine. The intravenous route is indicated in cases of non-rapid improvement in patients' receiving inhaled treatment.

Acute Disease↗