Education and experience improve transbronchial needle aspiration performance

To determine whether the diagnostic yield of transbronchial needle aspiration (TBNA) improves over time and to obtain insights about factors influencing its performance, we reviewed our experience during a 3-yr period. After serial multifaceted educational interventions directed toward bronchoscopists and their technical staff, TBNA yield increased significantly from 21.4 to 47.6% (p < 0.001). More frequent and more detailed notations in bronchoscopy reports (p < 0.05), a lower frequency of cytopathology specimens contaminated by endobronchial material (p < 0.05), and higher yields in patients with small cell carcinoma (p < 0.01) suggested that bronchoscopists' TBNA proficiency had increased. More frequent diagnoses with small cell carcinoma and fewer cytologically unsatisfactory specimens (p < 0.01) suggested that education of bronchoscopy technicians, and use of a direct smear technique for specimen preparation also contributed to improved TBNA yield. Increased experience with TBNA and focused education regarding its performance can enhance the role of this procedure in diagnosis and staging of patients with lung cancer.

A multicenter, matched case-control study of risk factors for equine laminitis

Risk factors for equine laminitis were examined in a prospective case-control study of the 258 cases seen at six collaborating veterinary teaching hospitals over a 32-month period. Case-control pairs were matched on institution, clinician, and season of diagnosis. The 90% of case-control pairs (78 acute, 155 chronic) that had complete data for age, gender, and breed were used in separate conditional logistic-regression models for acute and chronic laminitis. There was an increase in risk for horses with acute laminitis from 5 to 7 years of age (OR 4.7, 95% CI 1.3-16) and from 13 to 31 years of age (OR 3.9, 95% CI 1.3-12) (both compared to <5 years); risk was increased for chronic laminitis from 10 to 14 years (OR 3, 95% CI 1.4-6.8) and from 15 to 38 years (OR 2.9, 95% CI 1.4-6.1) (both compared to <6 years). Mares - but not stallions - were more likely than geldings to develop acute laminitis (OR 2.6, 95% CI 1.1-6.2) and chronic laminitis (OR 2.0, 95% CI 1.1-3.6). In the small acute-laminitis data set, the breed variable was collapsed into three categories: Thoroughbred (THB, reference), the Quarter Horse (QH), and other (non-QH-THB). The non-QH-THB group was at increased risk of acute laminitis (OR 3.8, 95% CI 1.2-11.8). For the seven breed-group categories used in the chronic-laminitis model, however, all non-THB breed groups appeared significantly at risk as compared to the THB, with odds ratios ranging from 3.3 (95% CI 1.3-8.30) for the QH to 9.1 (95% CI 2.1-39.3) for ponies.

Theophylline effect on the cerebral blood flow response to hypoxemia

Cerebral oxygen delivery (CO2D) remains nearly constant over a wide range of cerebral perfusion pressure and arterial oxygen content. In response to a decrease in arterial oxygen content secondary to hypoxemia, cerebral blood flow (CBF) increases, a response likely mediated by the release of adenosine. We studied the effect of theophylline, a potent adenosine antagonist, on CBF and cerebral oxygen delivery (CO2D) during hypoxemia in five healthy adult male volunteers. The CBF was measured using 133Xe clearance under conditions of (1) normoxemia (O2 saturation greater than 95 percent); (2) hypoxemia (O2 saturation = 80 percent); (3) normoxemia following aminophylline (the ethylene diamine salt of theophylline) 6 mg/kg intravenously; and (4) hypoxemia following aminophylline. Aminophylline decreased CBF and CO2D during both normoxemia and hypoxemia, but did not prevent the increase in CBF accompanying hypoxemia, suggesting that the increase in CBF in response to hypoxemia may not be mediated by adenosine or that customary doses of aminophylline are insufficient to inhibit adenosine-mediated cerebral vasodilation in response to hypoxemia. The significant decrease in CBF and CO2D observed following aminophylline is potentially clinically important and should be considered in the selection of bronchodilator therapy.

The effect of aminophylline on cerebral blood flow in patients with chronic obstructive pulmonary disease

Aminophylline has been shown to produce a reduction in cerebral blood flow (CBF) in animal models and patients with neurologic symptoms or signs. The effect of aminophylline on regional CBF (rCBF) in patients with chronic obstructive pulmonary disease (COPD) has not previously been reported to our knowledge. We studied the effect of loading and maintenance infusions of aminophylline on CBF in five subjects with moderate to severe COPD. rCBF was determined in eight homologous regions of each cerebral hemisphere at three intervals: (1) baseline; (2) following the IV loading dose of aminophylline (6.0 mg/kg body weight); and (3) early and late in the maintenance infusion (0.5 mg/kg/hr) period. Aminophylline loading caused a 26 percent reduction (p = 0.005) in mean rCBF from 40.6 +/- 5.2 (SD) ml/100 g/min to 30.1 +/- 6.0 ml/100 g/min. A 23 percent reduction (31.5 +/- 6.9 ml/100 g/min) persisted throughout the maintenance phase. Thus, aminophylline, as customarily used in subjects with COPD, is associated with a significant reduction in rCBF.

Protein kinase C activation increases binding of transcription factor PU.1 in murine tissue macrophages

PU.1 is a transcription factor found in macrophages, B cells, neutrophils, and hemopoietic stem cells. In macrophages PU.1 regulates a number of genes, including c-fms, CD11b, CD18, and FcgammaR1b. Previously, in primary macrophages PU.1 binding to the sequence GAGGAA was found to be induced by treatment with bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Here we investigated the role of protein kinase C (pKC) in the induction of PU.1 binding in macrophages. We report that pharmacological activation of pKC increases PU.1 binding, while inactivation of pKC inhibits the increases in PU.1 binding by agents which activate pKC in macrophages (LPS and tumor necrosis factor-alpha), but not by an agent which does not activate pKC (IFN-gamma). pKC activation may therefore be one pathway by which PU.1 binding may be increased in primary macrophages.

Cardiopulmonary effects of hypertonic saline in canine oleic acid-induced pulmonary edema

Vasoactive drugs may increase intrapulmonary shunt in patients with permeability edema. Because 7.5% hypertonic saline solution has cardiotonic properties, we studied its hemodynamic and pulmonary effects in a canine model of oleic acid-induced lung injury. Immediately after saline infusion, there were increases in cardiac output (2.0 +/- 0.1 to 3.4 +/- 0.2 L/min; p less than .001) and intrapulmonary shunt (50.3 +/- 4.4 to 57.3 +/- 3.2%; p less than .01) without alteration in arterial or mixed venous oxygen tension. Although arterial oxygen content decreased from 16.4 +/- 1.1 to 14.4 +/- 0.9 ml/dl (p less than .001), paralleling the change in hemoglobin concentration, oxygen delivery to the tissues increased from 327 +/- 23 to 486 +/- 36 ml/min (p less than .001). These effects were transient, inasmuch as all values returned to preinfusion levels within 30 min. Tissue oxygen consumption increased proportionately with cardiac output, and the directional change in arterial oxygenation was similar to the change in mixed venous oxygen tension. We conclude that tissue oxygen delivery improves after hypertonic saline infusion despite changes in intrapulmonary shunt and oxygen consumption. However, any benefit appears to be transient.

Ventricular septal defect in an infant chimpanzee (Pan troglodytes)

During clinical examinations and imaging studies of a prematurely born chimpanzee, a heart murmur, tachypnea, dyspnea, and disturbances of blood flow were observed. At necropsy, cardiomegaly, ventricular hypertrophy, and septal defects confirmed the presence of congenital VSD.

Pulmonary section development influences general medical house officer interests and ABIM certifying examination performance

To determine whether sectional development in pulmonary and critical care medicine influences medical house officers' (HO) interests and knowledge about respiratory medicine, we reviewed HO performance on the American Board of Internal Medicine (ABIM) certifying examination during 4 years before and 5 years after reorganization of our section. After major changes in the program and introduction of new educational opportunities, HOs more often selected pulmonary consultation electives (68.6% vs 47.8%; p = 0.009) and entered pulmonary fellowships after completion of residency training (12% vs 3%; p = 0.047). Total ABIM examination score did not change, but performance on its respiratory disease component improved from a median national percentile score of 48.5% (1986 to 1989) to 80.0% (1990 to 1994) (p = 0.0365). In relation to other specialty component scores, the rank of the respiratory disease percentile improved from the lowest specialty score to the highest. ABIM examination scores correlated with the cumulative faculty effort directed toward HO teaching (r = 0.70; p = 0.04) and the total number of clinical teachers (faculty and fellows) interacting with HOs (r = 0.73; p = 0.02). Academic development in pulmonary/critical care faculty has an important influence on medical HO interests in and knowledge of that discipline. Plans for the future structure of academic pulmonary/critical care sections must take into account this impact on the training of generalists. Although institutional priorities, resources, and shifting external forces will define how, where, and by whom respiratory medicine will be taught, an appropriate number of faculty members and sufficient commitment of their time to HO education must be preserved.

Atypical community-acquired pneumonia: concurrent infection with Chlamydia psittaci and Mycobacterium tuberculosis

We have presented a case of combined pulmonary infection with Chlamydia psittaci and Mycobacterium tuberculosis, both documented by culture of lymph nodes and respiratory secretions. We describe it not only as an unusual occurrence, but also to illustrate the importance of a systematic and thorough diagnostic approach to every case of pneumonia.