Anti-cardiolipin antibodies in sera from patients with periodontitis.

Antiphospholipid antibodies are commonly found in patients with systemic lupus erythematosus or the antiphospholipid syndrome, and a subset of such antibodies is associated with prothrombotic events such as stroke and with adverse pregnancy outcomes and fetal loss. We examined sera from 411 patients who were clinically characterized as to their periodontal disease status for serum levels of beta2-glycoprotein I-dependent anti-cardiolipin autoantibodies (anti-CL). The prevalence of patients with chronic periodontitis (CP) and generalized aggressive periodontitis (GAgP) positive for anti-CL (16.2% and 19.3%, respectively) was greater than that in healthy controls (NP) and localized aggressive periodontitis (LAgP) patients (6.8% and 3.2%). Patients with these autoantibodies demonstrated increased pocket depth and attachment loss compared with patients lacking the antibodies. Analysis of the data indicates that patients with generalized periodontitis have elevated levels of autoantibodies reactive with phospholipids. These antibodies could be involved in elevated risk for stroke, atherosclerosis, or pre-term birth in periodontitis patients.

Phosphorylcholine-dependent cross-reactivity between dental plaque bacteria and oxidized low-density lipoproteins.

Antibodies reactive with phosphorylcholine (PC) are ubiquitous in human sera, but the antigens stimulating their production and their function are not clear. Previous studies have shown that a significant proportion of dental plaque bacteria contain PC as determined by reactivity with PC-specific mouse myeloma proteins and monoclonal antibodies. Additionally, serum antibody concentrations of immunoglobulin (IgG) G anti-PC are higher in sera of individuals who have experienced periodontal attachment loss than those who are periodontally healthy. These data implicate the oral microflora as a source of antigen-stimulating anti-PC responses. Recent data also indicate that antibodies with specificity for PC are elevated in ApoE-deficient mice, a model for studies of athersclerosis, and that such antibodies bound oxidized low-density lipoproteins (LDL) (oxLDL) in atherosclerotic plaques. These data prompted the hypothesis that human anti-PC could bind to both oral bacteria and human oxLDL, and that these antigens are cross-reactive. We therefore examined the ability of human anti-PC to bind to PC-bearing strains of oral bacteria using enzyme-linked immunosorbent inhibition assays and by assessment of direct binding of affinity-purified human anti-PC to PC-bearing Actinobacillus actinomycetemcomitans. Our results indicated that PC-bearing strains of Streptococcus oralis, Streptococcus sanguis, Haemophilus aphrophilus, Actinomyces naeslundii, Fusobacterium nucleatum, and A. actinomycetemcomitans, as well as a strain of Streptococcus pneumoniae, absorbed up to 80% of anti-PC IgG antibody from human sera. Furthermore, purified anti-PC bound to a PC-bearing strain of A. actinomycetemcomitans but only poorly to a PC-negative strain. OxLDL also absorbed anti-PC from human sera, and oxLDL but not LDL reacted with up to 80% of the anti-PC in human sera. Furthermore, purified anti-PC bound directly to oxLDL but not to LDL. The data indicate that PC-containing antigens on a variety of common oral bacteria are cross-reactive with neoantigens expressed in oxLDL. We propose that PC-bearing dental plaque microorganisms may induce an antibody response to PC that could influence the inflammatory response associated with atherosclerosis.

Osteosarcoma of the patella with pulmonary metastases in a dog.

A 6-year-old neutered male Rottweiler was examined for a progressive right pelvic limb lameness. In radiographs of the right stifle, there was an osteolytic lesion with irregular new bone formation along the cranial aspect of the patella consistent with an aggressive bone lesion. In thoracic radiographs, there were multiple soft tissue nodular opacities throughout the lung fields, consistent with pulmonary metastases. Microscopically, fine needle aspirate samples from the right patella contained pleomorphic spindle cells with cytologic features of osteosarcoma. The presence of pulmonary metastases at the time of initial diagnosis in the dog described herein suggests that osteosarcoma of the patella has the potential for similar aggressive biologic behavior as that seen in dogs with appendicular osteosarcoma.

The first regioselective alpha-deprotonation and functionalization of allenamides. An application in intramolecular Pauson-Khand-type cycloadditions.

[rection: see text] The first regioselective alpha-deprotonation and functionalization of electron-deficient allenamines are described here. The acidities of alpha- and gamma-allenic protons of these allenamides are readily differentiated using strong bases, thereby allowing regioselective substitutions at either the alpha- or gamma-allenic position. A specific synthetic application of the novel alpha-substituted allenamides in intramolecular Pauson-Khand-type cycloadditions is also described here.

Invasion of human vascular endothelial cells by Actinobacillus actinomycetemcomitans via the receptor for platelet-activating factor.

Strains of the periodontal pathogen Actinobacillus actinomycetemcomitans are variable with respect to display of phosphorylcholine (PC)-bearing antigens. We have examined strains of A. actinomycetemcomitans with and without PC to assess their ability to invade endothelial cells via the receptor for platelet-activating factor (PAF). Results of antibiotic protection assays indicate that PC-bearing A. actinomycetemcomitans invade human vascular endothelial cells by a mechanism inhibitable by CV3988, a PAF receptor antagonist, and by PAF itself. The invasive phenotype was verified by transmission electron microscopy. A PC-deficient strain of this organism was not invasive. This property, in addition to the established ability of A. actinomycetemcomitans to invade epithelial cells, may provide this organism with access to the systemic circulation. The ability of PC-bearing oral bacteria to access the circulation may also explain the elevated levels of anti-PC antibody in serum found in patients with periodontitis.

Frequency of pulmonary mineralization and hypoxemia in 21 dogs with pituitary-dependent hyperadrenocorticism.

The purpose of this study was to determine the frequency of hypoxemia and pulmonary mineralization using 99mTc-methylene diphosphonate (99mTc-MDP) in dogs with pituitary-dependent hyperadrenocorticism (PDH). Twenty-one dogs with PDH were prospectively evaluated using thoracic radiography, arterial blood gas analysis, and bone phase and pulmonary perfusion scintigraphy (using 99mTc-macro-aggregated albumin [99mTc-MAA]). The radiographs and bone and perfusion studies were evaluated subjectively. An averaged quantitative count density ratio was calculated between the thorax and cranial thoraco-lumbar vertebrae from lateral thoracic 99mTc-MDP images. Thoracic:vertebral ratios were calculated using 99mTc-MDP studies from 21 control dogs. The thoracic:vertebral ratios were compared between the 2 groups (PDH and control). The mean age (+/-SD) of the 21 PDH dogs was 10.2 (+/-3) years, whereas the mean age of the control group was 9.8 (+/-3) years. Seven of the 21 dogs with PDH were hypoxemic (defined as an arterial partial pressure of oxygen [PaO2] < 80 mm Hg) with an average PaO2 (+/-SD) of 62 (+/-15) mm Hg. Of the 7 hypoxemic dogs, 2 were found to have pulmonary mineralization based on bone scintigraphic images. Pulmonary perfusion abnormalities were not identified using 99mTc-MAA in any of the 21 PDH dogs. Six PDH dogs had an abnormal interstitial pulmonary pattern and 5 of these dogs were hypoxemic. The average quantitative thoracic:vertebral ratio was not significantly different between the PDH and control dogs (0.5 +/- 0.4 versus 0.4 +/- 0.1, P = .16). Causes of hypoxemia other than pulmonary thromboembolism should be considered in dogs with PDH. Pulmonary mineralization may contribute to hypoxemia in dogs with PDH.

Use of a modified stomach tube for bronchoalveolar lavage in dogs.

A technique that did not require use of a bronchoscope for bronchoalveolar lavage (BAL) in dogs was developed. An inexpensive, readily available 16-F Levin-type stomach tube was modified for the procedure. The technique was effective for collecting BAL fluid in 9 dogs that ranged from 9.3 to 26.2 kg (20.5 to 57.6 lb). Recovered fluid was consistent with fluid collected bronchoscopically. Mean recovery volume was 84/125 ml (67%), mean WBC counts were high (> 300 cells/microl), and > 70% of cells were macrophages. Complications from use of the technique were not detected on the basis of pulse oximetry, thoracic radiography, and clinical observation. This effective, simple, and safe technique for BAL can be readily performed in clinical settings that do not have bronchoscopic capabilities. It also provides a less costly alternative than bronchoscopic BAL.

Imaging a spinal fracture in a Kohaku Koi (Cyprinus carpio): techniques and case history report.

An ornamental pet fish was diagnosed with a spinal fracture and subluxation involving truncal vertebrae 5 and 6 (T5-T6) using conventional radiography, nuclear scintigraphy, and computed tomography. Attempts to evaluate the dynamic nature of the lesion using conventional fluoroscopy in the unanesthetized, moving patient were unsuccessful. Adaptation of imaging techniques to accommodate a fish patient was not difficult and diagnostic images were obtained. The use of multiple imaging techniques was useful in the diagnosis and determination of the treatment plan of the spinal fracture in this patient.

Correlation between thoracic radiographic changes and remission/survival duration in 270 dogs with lymphosarcoma.

A retrospective study was undertaken wherein the medical records and thoracic radiographs of 270 dogs with lymphosarcoma were reviewed to determine the type and frequency of thoracic radiographic changes. Statistical evaluation of the relationship between radiographic, clinical and immunologic factors and the primary remission duration and survival times was performed using univariate and multivariate analysis. One hundred ninety-two dogs (71%) had some type of thoracic radiographic abnormality, including 80 dogs (29.6%) with pulmonary infiltrates and 164 dogs (64.4%) with thoracic lymphadenomegaly. Only T-cell phenotype (p = 0.0056 for survival, p = 0.0045 for remission) and the presence of cranial mediastinal lymphadenomegaly (p = 0.0005 for survival, p = 0.0129 for remission) were identified as having a significant negative correlation to both primary remission and survival duration by multivariate analysis.

Scintigraphic biodistribution and plasma kinetics of indium 111-labeled transferrin in dogs.

OBJECTIVE: To determine plasma clearance kinetics and imaging biodistribution of indium 111-labeled transferrin (111In-TF) in dogs. ANIMALS: 7 adult dogs. PROCEDURE: After 30 minutes' incubation of 18.5 MBq (0.5 mCi) of 111InCl3 with 1 ml of serum (n = 3) or 1 ml of plasma (n = 4) at 37 C, dogs were given autologous 111In-TF i.v., and serial blood samples and right lateral and dorsal scintigraphic images were obtained immediately and 1, 3, 5, 9, 22, and 48 hours later. Blood and plasma clearance kinetics were determined from a least-squares, nonlinear fit of the sample radioactivity data. Blood radioactivity was compared with plasma radioactivity to determine the extent of cellular labeling. Imaging biodistribution was characterized by subjective and objective assessment of blood pool, liver, gastrointestinal (abdomen) tract, kidney, and bone marrow activity. RESULTS: 111In-TF plasma clearance was best described by a biexponential fit, with early and late clearance half-times of 6 and 49 hours, respectively. The 111In was not redistributed between transferrin (plasma proteins) and blood cells. Imaging studies documented progressive liver and bone marrow uptake of the 111In-TF over 48 hours. Some radioactivity was evident in the colon of 1 dog on 48-hour images. Decay-corrected count rates (counts/pixel/mCi/kg/min) within the abdominal region of interest increased over the 48-hour imaging period and exceeded the blood pool (cardiac) activity at 20 hours after injection. CONCLUSION: 111In-TF has a biexponential plasma clearance in clinically normal dogs, with early and late clearance half-time of 6 and 49 hours, respectively. Scintigraphically, 111In-TF localizes to sites of iron storage (bone marrow and liver) over time. Some loss of 111In-TF via the gastrointestinal tract may be seen on late 48-hour images. CLINICAL RELEVANCE: 111In-TF appears to be a viable radiopharmaceutical for use in dogs, with specific application for identifying those with protein-losing enteropathy.

Thoracic radiographic findings in dogs infected with Rickettsia rickettsii.

Sixteen beagle dogs were injected intradermally with Rickettsia rickettsii. The dogs were divided into four groups (n = 4): 1) infected, non-treated control; 2) infected, treated with doxycycline; 3) infected, treated with doxycycline and an anti-inflammatory dose of corticosteroid; and 4) infected, treated with doxycycline and an immunosuppressive dose of corticosteroid. Thoracic radiographs were made and ocular fluorescein angiography was performed on days 6, 10, 17 post-inoculation. A mild interstitial lung opacity was noted in 4/16 dogs on day 6, 5/16 on day 10 and 3/16 on day 17 post-inoculation. Increased retinal vascular permeability was noted in 8/16 dogs on day 6, 3/16 on day 10 and 1/16 on day 17 post-inoculation. Correlation between the presence of radiographic and retinal lesions was not significant (p = 0.08). Eleven, naturally infected, dogs with thoracic radiographs and a final diagnosis of RMSF were also evaluated. Four of the 11 dogs had an unstructured interstitial pattern. Dogs with acute, experimentally-infected or naturally-occurring RMSF may have subtle pulmonary changes characterized by an unstructured interstitial pattern.

Scintigraphic evaluation of four dogs with protein-losing enteropathy using 111indium-labeled transferrin.

The purpose of this study was to determine the clinical utility of 111In-labeled transferrin (111In-TF) scintigraphy for evaluating dogs suspected of having protein-losing enteropathies. Four dogs were injected intravenously with autologous 111In-TF after 30 min incubation (at 37 degrees C) of 18.5 MBq (0.5 mCi) 111InCl3 with one ml of autologous plasma. Serial right lateral, left lateral and dorsal images were obtained 2, 4, and 24 hours post 111In-TF administration. Images were subjectively evaluated for the presence or absence of 111In-TF within the gastrointestinal tract. The results of total protein, albumin and globulin levels and results from gastrointestinal biopsies were recorded. In one dog, a follow-up scintigraphic study was done six months after initial evaluation and initiation of treatment for plasmocytic-lymphocytic enteritis. Gastrointestinal activity was noted by two hours in two dogs, while all four dogs had gastrointestinal activity on the 24 hour images. The mean (+/-std dev) plasma protein, albumin and globulin levels were 3.5 (+/-0.9), 1.7 (+/-1) and 1.8 (+/-0.3) respectively at the time of initial presentation. In the one dog that was evaluated after therapy, faint visualization of radioactivity within the colon was noted on the 24 hour image. Based on this study, 111In-TF appears to be a viable scintigraphic method for evaluating dogs with suspected protein-losing enteropathies. Potential limitations of this radiopharmaceutical include cost and prolonged isolation of the animal prior to release to the client due to the long physical half-life (T1/2 = 2.82 days).

Lameness and pleural effusion associated with an aggressive fibrosarcoma in a horse.

An 8-year-old Thoroughbred gelding was admitted for evaluation of chronic lameness of the left scapulohumeral joint of 3 months' duration. Radiography revealed a radiolucent lesion with the proximal portion of the humerus in the area of the metaphysis. Scintigraphy confirmed radiographic findings, with an increased uptake of technetium Tc 99m medronate in the proximal portion of the left humerus. A preliminary diagnosis of humeral fracture was made. Two weeks later, the horse was readmitted for clinical signs of respiratory distress. Radiographic and ultrasonographic evaluation revealed masses within the thoracic and abdominal cavities. The diagnosis was changed to neoplasm with multiple metastases. Because of the unfavorable prognosis, the horse was euthanatized. Necropsy findings confirmed an aggressive neoplasm. Special histochemical stains, immunohistochemistry, and electron microscopy were required to characterize the neoplasm as an anaplastic fibrosarcoma. Findings in this horse illustrate the importance of considering neoplasia, resulting in bone lesions, as a possible cause of chronic lameness in horses.

Ultrasonographic adrenal gland measurements in dogs without evidence of adrenal disease.

The purpose of this retrospective study was to determine measurements of adrenal glands from longitudinal sonograms, in a large population of dogs and to correlate these measurements to age, sex and descriptors of body size. Dogs were selected from the clinic population presented for routine abdominal ultrasonography between September, 1991 and March, 1994. Dogs with elevated serum cholesterol or alkaline phosphatase levels, polyuria/polydipsia, and/or clinical diagnoses of adrenal pathology were excluded. Dogs with ultrasound-documented abnormalities (mass lesions, abnormal architecture) of either adrenal were not considered. Age, sex, weight and breed were recorded, and the body surface area of each dog was calculated. Adrenal length and caudal polar width were determined from longitudinal, two-dimensional ultrasound images. Adrenal measurements were compared with body size measurements and age using least squares linear regression analysis and the correlation coefficient (r) and coefficient of determination (r2) calculated. One hundred and ninety three dogs were included in the study, with a weight and body surface area range of 1.8-72 kg and 0.2-1.8 m2, respectively. The left adrenal gland (n = 182) length range was from 10.7 to 50.2 mm, and the range of the caudal polar widths was 1.9 to 12.4 mm. Right adrenal gland (n = 85) length range was from 10 to 39.3 mm, and the range of the caudal polar widths was from 3.1 to 12 mm. In dogs where both adrenal gland lengths were measured (n = 74), the right adrenal gland length was less than that of the left in 46 dogs, equal to the left in one dog, and greater than the length of the left in 27 dogs. The strongest linear association was noted between the left adrenal gland length and body weight (kg, r = 0.71, p < 0.0001) or body surface area (m2, r = 0.71, p < 0.0001). Similar significant association was noted between the right adrenal gland length and body weight (kg, r = 0.69, p < 0.0001). A significant positive association was also noted between age and left adrenal gland length, (r = 0.25, p = 0.009). The summation of all four adrenal measurement values (left length and width, right length and width) did slightly improve the correlation (r = 0.74, p < 0.0001) when compared with body weight (kg). There was not a significant difference in the adrenal measurements with regard to sex. With regard to the correlation coefficient values, there was no advantage noted to calculating the body surface area from body weight. The causes for the low degrees of the correlation between adrenal size and the variables investigated in this study are unknown; measurement error, effects of non-adrenal illness on adrenal size, and a non-linear or complex linear relationship between adrenal gland size (as measured by longitudinal parameters) and descriptors of body size are among possible explanations.

Uptake and retention kinetics of para-fluorine-18-fluorobenzylguanidine in isolated rat heart.

UNLABELLED: Para-[18F]fluorobenzylguanidine ([18F]PFBG) is a newly developed tracer for imaging myocardial sympathetic neuronal innervation. This study investigated the uptake and retention mechanisms of [18F]PFBG in perfused, isolated rat heart. METHODS: Fluorine-18-PFBG was administered to working rat hearts within the perfusion medium at a constant activity concentration (1.5-2 MBq/liter) for 8 min, followed by a washout period (50 min). External scintillation probes with coincidence detection circuitry were used to measure myocardial radioactivity. Six groups of hearts (n = 6, except in Group 6) were studied: (Group 1) control; (Group 2) 100 nM desipramine (DMI); (Group 3) 0.8 microM SKF550; (Group 4) DMI + SKF550; (Group 5) SKF550 + 1.0 microM Ro 4-1284; and (Group 6) SKF550 with DMI chase at 30 min (n = 4). RESULTS: Groups 2, 3 and 4 showed a mean reduction of 19% (uptake-1 blockade), 58% (uptake-2 blockade) and 95% (uptake-1 and uptake-2 blockade) in uptake rates, respectively, compared with control (p < 0.01). A further 33% reduction in the uptake rate was noted with vesicular transport inhibition (Group 5 compared with 3, p = 0.054). Biphasic clearance consisting of rapid (T1/2 = 5.32 +/- 1.1 min) and slow (T1/2 = 35.2 +/- 9.6 min) components were noted in control hearts. The rapid (T1/2 = 1.6 +/- 0.3 min) and slow (T1/2 = 10.9 +/- 1.4 min) clearance rates were accelerated (p < 0.0001) in Group 5 compared to control. DMI chase conditions (Group 6) caused an inhibition of [18F]PFBG washout (p = 0.004) suggesting a role for reverse transport through the uptake-1 carrier. CONCLUSION: Fluorine-18-PFBG is specifically accumulated by sympathetic nerve terminals. However, further work is recommended in humans to evaluate the potential implications of specific extraneuronal uptake of [18F]PFBG through the uptake-2 mechanism.

Unilateral nephrectomy in dogs with renal disease: 30 cases (1985-1994).

OBJECTIVE: To evaluate indications for and complications, efficacy, and effects on renal function of unilateral nephrectomy in dogs with renal disease, and to evaluate the role that scintigraphy had in the decision to excise a kidney. DESIGN: Retrospective case series. ANIMALS: 30 dogs with renal disease that underwent unilateral nephrectomy. A comparison group of 12 dogs with renal calculi that underwent renal scintigraphy but not nephrectomy was included. RESULTS: Indications for nephrectomy included renal or ureteral calculi (n = 10), renal mass (8), chronic pyelonephritis (5), perirenal mass (3), severe hydronephrosis and hydroureter (3), and renal hypoplasia with ureteral ectopia (1). None of the dogs were azotemic before surgery. Renal scintigraphy apparently influenced the decision to perform nephrectomy, because in 14 of 16 dogs that underwent nephrectomy, the affected kidney contributed < or = 33% of the total glomerular filtration rate, but in 6 of 8 comparison dogs that underwent nephrotomy, the affected kidney contributed > 33% of total glomerular filtration rate. Complications of nephrectomy included oliguria (5) and organ laceration (2). Mean +/- SD final serum creatinine concentration for 16 dogs alive at least 6 months after nephrectomy was 2.2 +/- 1.8 mg/dl. Three dogs had chronic renal failure of undetermined cause at the time of death. Nephrectomy did not completely resolve the underlying disease in 13 dogs. Renal function was evaluated in 6 dogs 2 to 3.5 years after nephrectomy and was impaired in 4. None of the dogs were anemic, azotemic, proteinuric, or hypertensive. Survival time varied depending on the underlying disease. CLINICAL IMPLICATIONS: Multiple factors contributed to the decision to perform nephrectomy. Unilateral nephrectomy resulted in few serious complications and was not detrimental to the remaining kidney, but did not always resolve the underlying disease.

Para-[18F]fluorobenzylguanidine kinetics in a canine coronary artery occlusion model.

BACKGROUND: The kinetics of para-[18F]fluorobenzylguanidine ([18F]PFBG) were investigated in a canine coronary artery occlusion model. METHODS AND RESULTS: Five dogs were imaged by positron emission tomography (PET) before and after complete surgical ligation of the left anterior descending coronary artery. PET studies included a 10-minute dynamic [13N]NH3 perfusion scan, followed 1 hour later by 3-hour dynamic [18F]PFBG scanning. [18F]PFBG and [13N]NH3 images demonstrated homogeneous myocardial uptake/perfusion before infarction. One hundred eighty minutes after [18F]PFBG administration, myocardial accumulation was decreased by 60% (day 2, 0.0065% +/- 0.0015% injected dose/ml) and 58% (day 16, 0.0069% +/- 0.003% injected dose/ml) compared with a similar myocardial region of interest from the preinfarction (0.016% +/- 0.005% injected dose/ml) study. Myocardial accumulation of [13N]NH3 at 9 minutes showed a 52% (day 2) and 7% (day 16) decrease compared with the preinfarction study. The accumulation of [18F]PFBG in the infarction was decreased significantly at 120 and 180 minutes on all postinfarction studies (p = 0.01). In three dogs a significant decrease in the myocardial norepinephrine concentration was documented in the area of infarction (237 +/- 94 ng/gm) versus the noninfarcted (1018 +/- 48 ng/gm) myocardium (p = 0.001). CONCLUSIONS: A decreased accumulation of [18F]PFBG was observed in the area of myocardial infarct in this canine model. The magnitude of the decrease in [18F]PFBG was larger than that seen with [13N]NH3 on day 16 after infarction, suggesting reperfusion and persistent sympathetic neuronal dysfunction.

Retention of insoluble particles after local intrabronchial deposition in dogs.

Recent studies have challenged the generally accepted hypothesis that bronchial particle clearance is complete within 24-48 h postdeposition. We studied bronchial retention of inert particles using a bronchoscope and microspray nozzle to localize deposition in a bronchus while avoiding alveolar deposition. Six-microliter aliquots (444 kBq) of submicrometer (number mean diameter = 0.22 microns, geometric standard deviation = 1.75) technetium-99m-labeled (99mTc) sulfur colloid (SC) particles (n = 6) or the unbound radiolabel 99mTc-pertechnetate (99mTcO4-; n = 3) were sprayed onto a 5-mm-diam bronchus in halothane-anesthetized dogs. Radioactivity at the deposition site and clearance pathway was monitored externally with a gamma camera beginning immediately postspray. Bronchial retention of SC was 8.5 +/- 2.4 and 1.5 +/- 0.7% at 3 and 24 h postspray, respectively. Tracheal mucus velocity was measured at 10.4 +/- 2.2 mm/min. For comparison, clearance of inhaled submicrometer SC particles was also measured in the same dogs. Retention of inhaled aerosolized SC (peripheral lung deposition) was 98.1 +/- 1.1 and 76.3 +/- 1.8% at 3 and 24 h, respectively. 99mTcO4- cleared from the bronchi slightly more rapidly than did SC. Radioactivity was readily detected in the blood after deposition of 99mTcO4- but not of SC. Thus SC cleared by mucociliary transport, whereas 99mTcO4- cleared predominantly by transepithelial absorption. We conclude that clearance of submicrometer particles from a 5-mm conducting airway is very nearly complete by 24 h, with approximately 92% of the clearance occurring within the first 3 h postdeposition.

Inspired anaesthetic gas humidification improves thermal uniformity during canine whole body hyperthermia.

Supplying warmed saturated water vapour in anaesthetic gases during whole body hyperthermia (WBH) could potentially improve thermal uniformity in the trachea and esophagus. Four normal dogs were anaesthetized for WBH at 42 degrees C. A Puritan Bennett Cascade humidifier was used to supply anaesthetic gases saturated with water vapour at an average airway temperature of either 42 degrees C or 38 degrees C. Esophageal temperature was monitored at the thoracic inlet and 5 cm cephalad. Thermal dose was estimated by calculating equivalent minutes for an isoeffect at 43 degrees C (CEM 43 degrees Tx, where Tx is the site of temperature measurement). Endotracheal mucociliary transport velocity (MCTV) was determined before and 48 h following WBH by 99mTc-MAA scintigraphy. Compared to the 38 degrees C humidified gas group, dogs receiving 42 degrees C humidified gas reached 42 degrees C faster (p = 0.02) and had CEM 43 degrees T(esophageal) values equivalent to the target CEM 43 degrees T(rectal). Endotracheal MCTV with 42 degrees C humidified gas, however, was reduced 53% from baseline 48 h following WBH (p = 0.02). With 38 degrees C humidified gas, endotracheal mucociliary transport velocity was unchanged from baseline 48 h post WBH. Tracheal histology was examined using light and electron microscopy in four additional dogs euthanatized following 90 min of 42 degrees C humidified gas combined with WBH. There was no histological evidence of tracheal or lung thermal damage with 42 degrees C humidified gas in these four dogs. However, a moderate increase in tracheal goblet cell secretory granule staining was observed. This change could imply temporary heat-induced ciliary microtubule dysfunction, rather than decreased mucus production, as the likely mechanism of reduced mucociliary transport velocity 48 h following WBH. Administration of 42 degrees C humidified anaesthetic gases with WBH improves heating rate and esophageal thermal uniformity but temporarily depresses tracheal mucociliary transport velocity.