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PubMed2005

The incremental contribution of clinical breast examination to invasive cancer detection in a mammography screening program.

OBJECTIVE: The objective of this study was to determine the potential added contribution of clinical breast examination (CBE) to invasive breast cancer detection in a mammography screening program, by categories of age and breast density. SUBJECTS AND METHODS: We prospectively followed 61,688 women aged 40 years or older who had undergone at least one screening examination with mammography and CBE between January 1, 1996, and December 31, 2000, for 1 year after their mammogram for invasive cancer. We computed the incremental sensitivity, specificity, and positive predictive value of CBE over mammography alone for combinations of age and breast density (predominantly fatty or dense). RESULTS: Mammography sensitivity was 78% and combined mammography-CBE sensitivity was 82%, thus CBE detected an additional 4% of invasive cancers. CBE detected a minority of invasive cancers compared with mammography for all age groups and all breast densities. Sensitivity increased from adding CBE to screening mammography for all ages, from 6.8% in women ages 50-59 with dense breasts to 1.8% in women ages 60-69 years with fatty breasts. CBE generally added incrementally more to sensitivity among women with dense breasts. Specificity and positive predictive value declined when CBE was used in conjunction with mammography, and this decrement was more pronounced in women with dense breasts. CONCLUSION: CBE had modest incremental benefit to invasive cancer detection over mammography alone in a screening program, but also led to greater risk of false-positive results. These risks and benefits were greater in women with dense breasts. The balance of risks and benefits must be weighed carefully when evaluating the inclusion of CBE in a screening examination.

Adult↗
PubMed1986

Effects of a cotton bract extract on guinea pig isolated airway smooth muscle.

The effects of a water extract of cotton bracts (CBE) on guinea pig isolated trachealis smooth muscle was studied. The ability of CBE to evoke tension responses, to modify tissue reactivity to excitatory and inhibitory agents, and to modify electric field stimulation-induced neurogenic responses was evaluated. CBE caused contraction in low concentrations, which were not mediated by histamine H1-, muscarinic, or 5-hydroxytryptamine (5-HT) receptors, and caused relaxation in high concentrations. In the presence of CBE, the maximum contractile response to 5-HT and the sensitivity to KCl were reduced. The maximum relaxation responses and sensitivities to adenosine and ATP were increased by CBE. In contrast, contractile responses to histamine and methacholine and relaxation responses to isoproterenol were unaffected. Neurogenic cholinergic excitatory responses and neurogenic adrenergic responses did not appear to be affected by CBE. However, the relaxant effect of nonadrenergic inhibitory nerve stimulation was increased in the presence of CBE. These findings differ from previous ones observed in our laboratory for dog isolated trachealis smooth muscle preparations, which indicates that the effects of CBE in isolated airways is species-dependent. Virtually all of the contractile activity of CBE was dialyzable (molecular weight less than 14,000) and retained in ashed samples. Inorganic constituents may contribute to the spasmogenic activity of CBE.

Adenosine↗
PubMed2005

Screening clinical breast examination: how often does it miss lethal breast cancer?

BACKGROUND: Although most American women regularly receive screening clinical breast examination (CBE), little is known about CBE accuracy in community practice. We sought to estimate the rate of cancer detection (sensitivity) of screening CBE performed by community-based clinicians on women who ultimately died of breast cancer, as well as to identify factors associated with accurate detection. SUBJECTS AND METHODS: We evaluated CBE accuracy among asymptomatic female health plan enrollees in five states (WA, OR, CA, MA, and MN) who received a CBE within 1 year of breast cancer diagnosis and who died of breast cancer within 15 years of diagnosis (N = 485). Sensitivity was estimated as the proportion whose exam was abnormal. Bivariate and logistic regression analyses identified patient characteristics associated with cancer detection. RESULTS: An abnormality was noted on screening CBE in one of five women who ultimately succumbed to breast cancer (sensitivity = 21.6%; 95% confidence interval [CI] = 18.1% to 25.6%). The odds of a true-positive screening CBE (sensitivity) were decreased among women using estrogen (odds ratio [OR] = 0.23; 95% CI = 0.07 to 0.80), receiving a Pap smear during the same visit as CBE (OR = 0.45; 95% CI = 0.27 to 0.72), and with increasing chronic disease comorbidity (P(trend) = .08). CONCLUSION: Screening CBE as performed in the community may be insufficiently sensitive to detect most lethal breast cancers. Low sensitivity of screening CBE in community practice may be partly attributable to its performance alongside time-consuming clinical tasks such as Pap smear screening or chronic illness care.

Adult↗
PubMed1987

Blood clonal B cell excess at diagnosis in multiple myeloma: relation to prognosis.

112 patients with multiple myeloma have been studied at diagnosis for the presence of blood clonal B-cell excess (CBE), defined as a ratio between kappa+ and lambda+ lymphocytes outside the normal range (0.9-3.5). 48 patients (43%) had CBE. The increase in light chain-bearing lymphocytes was always that of the M component light chain isotype. The proportions of patients exhibiting CBE were the same in different stages. The response frequency was not influenced by the presence of CBE. However, patients with CBE had a shorter remission duration time (p less than 0.001) and total survival (p less than 0.05) than those without CBE. This was also noticed when each clinical stage was analyzed separately. Moreover, survival was shorter in patients with a large fraction of CBE than in those with a small one. Cox regression analysis revealed that CBE was a much stronger predictor of remission duration than age, clinical stage and renal dysfunction. CBE and response to initial treatment independently were the best factors to indicate survival. It is suggested that analysis of CBE should be included in the clinical characterization of untreated patients with multiple myeloma.

Adult↗
PubMed2006

Clinical breast examination in a comprehensive breast cancer screening program: contribution and cost.

PURPOSE: To retrospectively evaluate the cost of clinical breast examination (CBE) and its contribution to screening mammography in the detection of breast cancer. MATERIALS AND METHODS: The study received a waiver of authorization from the institutional review board, informed patient consent was not required, and the study was compliant with HIPAA regulations. The records of 60 027 consecutive asymptomatic patients who underwent screening mammography were retrospectively reviewed. CBE was performed on all patients by a nurse practitioner. Patients with positive CBE findings were required to convert from screening to diagnostic evaluation; the number of cancer diagnoses that resulted was determined. The reports, four-view mammograms, or both of patients requiring conversion to diagnostic evaluation were reviewed to determine those patients likely to undergo diagnostic imaging on the basis of screening mammographic findings alone. The cost of CBE was calculated and divided by the number of cancers detected solely with CBE to determine the cost of CBE per additional cancer detected. RESULTS: Four hundred seventy-four (age range, 32-95) of 60 027 asymptomatic patients had positive CBE findings which required conversion to diagnostic evaluation. Forty-six cancers in 44 patients were subsequently diagnosed; 32 would have been detected with mammography alone, whereas 14 were imperceptible at screening mammography. The cost of CBE was $122 598 per cancer detected solely with positive CBE findings. CONCLUSION: CBE performed by nurse practitioners led to the diagnosis of 14 cancers in 13 patients with mammographically occult tumors (0.02% of the screening population and approximately 3% of all cancers diagnosed at the facility during this study). The cost of detecting these additional cancers is estimated to be $122 598 per cancer.

Adult↗
PubMedDate not supplied

Performance and reporting of clinical breast examination: a review of the literature.

Clinical breast examination (CBE) seeks to detect breast abnormalities or evaluate patient reports of symptoms to find palpable breast cancers at an earlier stage of progression, when treatment is more effective and treatment options are greater than for later stage disease. Evidence suggests that, for some women, CBE can be an important complement to mammography in the earlier detection of breast cancer; CBE identifies some cancers missed by mammography and provides an important screening tool among women for whom mammography is not recommended or women who do not receive high-quality screening mammography according to recommended guidelines. But CBE performance and reporting approaches are inconsistent. Health care providers indicate that they are not confident in their CBE skills and would welcome training. Studies demonstrate that training can enhance CBE performance, measured in terms of execution of CBE components and accuracy. This literature review provides evidence to the extent that it is available, to support the specific recommendations of Saslow, et al. for optimizing CBE performance and reporting and to guide further research on CBE performance characteristics, reporting systems, barriers to high-quality CBE performance, and training.

Breast Neoplasms↗
PubMed1995

Residents' breast examination performance. How often? How well?

The American Cancer Society recommends annual clinical breast examination (CBE) for women with average risk of breast cancer beginning at age 40. The purpose of the current chart review study was to determine the adequacy of CBE performed by house officers in a community teaching hospital. A chart audit of 92 women aged 50 or older who were consecutively admitted to the medical service was used as a baseline measure of CBE documentation. Two subsequent series of 100 women each were evaluated. The first series, which also involved women admitted to the medical service, followed increased emphasis on the importance of CBE during twice daily conferences with supervisor staff. The second series involved women admitted to the obstetrics/gynecology service. In that series, house staff used two history/physical examination forms: one with a slot dedicated to CBE and one without a dedicated slot. Results indicate that supervisors' stressing the importance of CBE resulted in only slight improvement in house officers' performance, even in the presence of risk factors for breast cancer. In the third chart audit, CBE was documented by 88% of house staff who used a form with a dedicated slot for CBE; there were no CBE documentations among staff who used a form without a dedicated slot. The dedicated form was more successful in increasing CBE performance and documentation than verbal emphasis about the importance of breast cancer screening.

Breast Neoplasms↗
PubMed2006

Outcome of screening by clinical examination of the breast in a trial in the Philippines.

The value of screening by Clinical Examination of the Breast (CBE) as a means of reducing mortality from breast cancer (BC) is not established. The issue is relevant, as CBE may be a suitable option for countries in economic transition, where incidence rates are on the increase but limited resources do not permit screening by mammography. Our aims were to assess whether mass screening by CBE carried out by trained para-medical personnel is feasible in an urban population of a low-income country, and its efficacy in reducing BC mortality. Our study was designed as a randomised controlled trial of the effect on BC mortality of 5 annual CBE carried out by trained nurses. The target population was women aged 35-64 years, resident in 12 municipalities of the National Capital Region of Manila, Philippines. The units of randomization were the 202 health centres (HC) within the selected municipalities. During 1995 nurses and midwives were recruited and trained in performing CBE. The first round of screening took place in 1996-1997. The intervention however showed a refractory attitude of the population with respect to clinical follow-up and was discontinued after the completion of the first screening round. Cases of breast cancer occurring in the study population during 1996-1999 were identified by the 2 local population-based registries. In the single screening round 151,168 women were interviewed and offered CBE, 92% accepted (138,392), 3,479 were detected positive for a lump and referred for diagnosis. Of these only 1220 women (35%) completed diagnostic follow-up, whereas 42.4% actively refused further investigation even with home visits, and 22.5% were not traced. Of 53 cases that occurred among screen-positive women in the 2 years after CBE only 34 were diagnosed through the intervention. Eighty cases occurred among screen-negative women. The test sensitivity for CBE repeated annually was 53.2%. The actual sensitivity of the programme was 25.6% and positive predictive value 1%. Screen-detected cases were non-significantly less advanced than the others. Previous studies have shown that most breast cancer cases in the Philippines present at advanced stages and have an unfavourable outcome. Although CBE undertaken by health workers seems to offer a cost-effective approach to reducing mortality, the sensitivity of the screening programme in the real context was low. Moreover, in this relatively well-educated population, cultural and logistic barriers to seeking diagnosis and treatment persist and need to be addressed before any screening programme is introduced.

Adult↗
PubMed1988

Acute pulmonary response to cotton bract extract in monkeys: lung function and effects of mediator modifying compounds.

It is well established that cotton dust inhalation can compromise lung function in textile workers. Challenges with a water-soluble extract of cotton bract (CBE) can also induce reversible airway obstruction in healthy volunteers. We have examined the effect of inhaled CBE in nonhuman primates and have attempted to inhibit the bronchoconstrictive response with mediator modifying compounds. CBE (34 mg/ml or 100 mg/ml) was administered via IPPB for 15 minutes (15 breaths/min) in 12 intubated, anesthetized, adult male monkeys (Macaca fascicularis). Breath-by-breath determinations of pulmonary resistance, dynamic compliance (Cdyn), tidal volume, and breathing frequency were calculated from the transpulmonary pressure (esophageal balloon) and airflow signals and monitored for 2 hr postchallenge. Control challenges with distilled water were also performed in 3 monkeys with the greatest response from CBE. Five animals (42%) were found to respond to CBE with peak % changes in Cdyn greater than 45%. In 3 of these animals, we attempted to blunt the CBE response with chlorpheniramine (0.1 mg/kg i.v.) and a mast cell stabilizer lodoxamide (0.1 mg/ml aerosol). In these 3 animals the mean (+/- SD) peak % changes in Cdyn to CBE alone was -47.4 +/- 1.8. The CBE response following chlorpheneramine was -49 +/- 15.7 and following lodoxamide was -47.0 +/- 5.4. These data suggest that monkeys, like humans, can develop reproducible bronchoconstriction following an aerosol challenge with CBE. Furthermore, this bronchoconstriction in the monkey is probably not explained by the action of histamine or mediator release alone and an acute inflammatory reaction may be involved.

Animals↗
PubMed1989

The effect of cotton bract extract on respiratory glycoconjugate secretion from human airways in vitro.

In vivo and in vitro studies with a water-soluble extract of cotton bracts (CBE) suggest that CBE may be responsible for some of the clinical manifestations of byssinosis. Since chronic bronchitis has been repeatedly documented as a major feature of byssinosis, we studied the effect of CBE on respiratory glycoconjugate (RGC) release from human airways (HAs) in vitro. HAs were incubated with [3H]glucosamine to label RGC molecules. CBE in increasing concentrations was added to radiolabeled HAs, and the release of 3H-RGC, histamine, and other mediators was measured. CBE in concentrations of 1 to 7 mg/ml caused a dose-related increase in RGC, as well as histamine release (RGC, 14% to 45% increase above control; histamine, 12 to 70 ng/ml released concurrently). Additionally, CBE in a dose of 5 mg/ml caused a more than threefold increase in peptidoleukotriene production above baseline. The effect of histamine H1 and H2 (pyrilamine and cimetidine), cyclooxygenase pathway inhibitor (indomethacin), leukotriene (LY 171883 and FPL 55712), and lipoxygenase pathway (BW nordihydroguaiarectic acid) blocking agents on CBE-induced RCG secretion was studied. In addition to histamine-H1 blockers, lipoxygenase inhibitors (nordihydroguaiarectic acid and BW 755C) and leukotriene blockers (FPL 55712 and LY 171883) are also potent inhibitors of CBE-induced RGC secretion. This suggests that CBE may act via the release of several mediators (histamine and leukotrienes), possibly from airway cells, such as mast cells, macrophages, or epithelial cells, to stimulate RGC secretion.

Bronchi↗
PubMed2003

Screening clinical breast examination.

Evidence suggests that CBE detects most breast cancers found by mammograms, and also some that mammograms miss, particularly in younger women. Recent estimates suggest that screening CBE has a sensitivity of about 54% and a specificity of about 94%. Yet, the impact of screening CBE on breast cancer mortality is still not clear, as there are no trials that have reported results comparing screening CBE alone to no screening. In some countries, the costs of screening mammography are considered too high, and policy makers are considering implementing screening programs based on CBE rather than mammography. In those countries with screening mammography programs already in place, screening CBE should also be included, as this will increase the overall sensitivity of breast cancer screening. Studies have shown that community health workers can be trained to conduct screening CBE, and that trained nurses perform CBE as well as physicians. Physicians should take on the responsibility to ensure that screening CBE is performed properly, however, and that it remains an integral part of all screening mammography programs.

Adult↗
PubMed2003

Risk factors for failure to detect a cancer during clinical breast examinations (United States).

BACKGROUND: Although clinical breast examinations (CBEs) provide important opportunities to detect breast cancer, little is known about factors that affect cancer detection during CBEs performed in community settings. To evaluate several potential factors, we analyzed data from 1,056,153 cancer screening records reported to the National Breast and Cervical Cancer Early Detection Program (NBCCEDP). METHODS: Using case-series methods, we compared 2159 cancers missed during CBEs with 3161 cancers detected during CBEs. Cancers missed during CBE were found by mammography and confirmed by biopsy or fine needle aspiration. RESULTS: After controling for cancer stage, tumor size, and breast symptoms at time of CBE, we found that patient age and CBE history were significantly associated with the likelihood of cancer detection. Compared to women 50-59, women 40-49 were more likely to have their cancer detected during CBE (odds ratio (OR) = 1.84, 95% confidence interval (95% CI) 1.47-2.29), while women 70 and older were less likely to have it detected (OR = 0.74, 95% CI: 0.55-1.00). Among women receiving their first NBCCEDP-funded CBE, 67.5% had their cancer detected by CBE. Among women receiving their second or third CBE, the values were 59.3 and 48.8%, respectively. In an adjusted logistic model, a significant inverse relationship was observed between number of prior CBEs and percent of cancers detected in the index CBE (OR = 0.79, 95% CI: 0.72-0.88). CONCLUSIONS: Among women diagnosed with breast cancer, older women and those who have had multiple CBEs were more likely to have their cancer missed during CBE.

Adult↗
PubMed2004

Predictors of clinical breast examination among South Asian immigrant women.

To determine predictors of clinical breast examination (CBE) among South Asian immigrant women residing in Toronto, Canada. A cross-sectional self-administered survey with women patients visiting family physician group practices. Fifty-four women participated in the study (response rate 77%). Twenty women (38.5%) "ever had" CBE. Compared to women who never had CBE, women who had CBE were statistically older, had lived more years in Canada, had better knowledge of breast cancer, had lower perceived barriers to CBE, and were more likely to have ever had a periodic health exam. No significant differences were found between the two groups for education, employment, English language abilities, perceived health, and perceived benefits of CBE. A direct logistic regression with five predictor variables, significant at a univariate level, was statistically reliable, chi(2) (5, n=51) = 34.7, p < 0.001 and explained 67% of the variance in the CBE status. Age and perceived barriers to CBE remained significant over and above other predictor variables. The odds of "ever had" CBE increased with age and decreased with more perceived barriers. The study highlights the need for education interventions on breast cancer and screening among SA recent immigrant women.

Adult↗
PubMed2001

Prevalence of obstructive lung diseases and respiratory symptoms in relation to living environment and socio-economic group.

We wanted to test whether living environment, occupation and social position are risk factors for asthma and chronic bronchitis/emphysema (CBE). The prevalence of bronchial asthma, CBE, respiratory symptoms and smoking habits in a random sample of 12,071 adults aged 20-59 years was assessed in a postal survey with a slightly modified questionnaire previously used in central and northern Sweden (The OLIN studies). Occupation was coded according to a socio-economic classification system. Six different living environment areas were defined; city-countryside, seaside-not seaside and living close to heavy traffic-not living close to heavy traffic. Multiple logistic regression analysis (forward conditional) was applied to estimate the association between the proposed set of risk factors and self-reported obstructive lung diseases and lower respiratory symptoms controlling for age, gender and smoking. After two reminders, the response rate was 70.1% (n=8469); 33.8% of the responders were smokers. In all, 469 subjects (5.5%) stated that they had asthma and 4.6% reported CBE. Besides smoking, which was a risk for both asthma and CBE, there were different risk patterns for self-reported asthma and CBE. In the economically active population there was a tendency that CBE was more common among 'unskilled and semi-skilled workers'. This fact was further emphasized when the population was merged into the two groups 'low social position' and 'middle/high social position', with 'low social position' as a risk for CBE (OR=1.35, 95% CI=1.06-1.72). No social risk factors were identified for asthma. Living close to heavy traffic was a risk factor for asthma (OR=1.29, 95% CI=1.02-1.62) but not for CBE. Apart from this no living environmental risk factors for obstructive pulmonary diseases were identified. Asthma symptoms and long-standing cough were more common among those subjects living close to heavy traffic compared to those not living close to heavy traffic. To conclude, low social position was a risk factor for CBE and living close to heavy traffic was a risk factor for asthma.

Adult↗
PubMed2006

Does Community-Based Education come close to what it should be? A case study from the developing world: students' opinions.

CONTEXT: There has been an increase in the number of medical schools implementing community-based educational (CBE) programmes. However, there are doubts whether CBE programmes are appropriately implemented. As a case study, the CBE programme of the Medical Faculty of Diponegoro University (MFDU) in Semarang, Indonesia was evaluated. OBJECTIVES: To acquire MFDU's students' opinions on their CBE programme as part of a comprehensive evaluation of that programme, and to generate recommendations for improvement of MFDU's CBE programme. METHODS: Coles and Grant's model for curriculum evaluation was applied. This model recommends triangulation of data generated from comparison of the programme as designed "on paper", as implemented "in action" by the faculty, and "as experienced" by the students. To assess the curriculum as experienced by the students, direct participatory observation was performed and focus group discussions were conducted to collect students' opinions. RESULTS: Students specifically signalled: (1) frequent overlap of lectures given during the CBE clerkship and in the previous part of the curriculum, (2) mismatch between their activities in the community and the community's felt health needs, (3) greater benefits of the CBE programme for Primary Health Care (PHC) centres and students than for target communities, and (4) incidental defective co-operation between students and health providers or community health workers. CONCLUSION: Students' opinions yielded more in-depth information on the CBE programme evaluated and facilitated formulation of recommendations for improvement of that CBE programme.

Community Medicine↗
PubMed1999

Clinical breast examination in primary care: perceptions and predictors among three specialties.

To assess predictors of reported performance of screening clinical breast examination (CBE) by internists, family physicians, and obstetrician/gynecologists, we surveyed members of these specialties in four counties of Washington State. We contacted all physicians in the counties and identified 334 providers who saw women ages 50-75 and provided primary care as their principal activity. Seventy-five percent (252 of 334) responded. Physicians were mailed a survey and contacted for telephone completion if they did not respond in writing. The survey inquired about their current performance of CBE and factors that might predispose, enable, or reinforce its use. Differences across specialties were assessed using the chi-square statistic. Factors associated with reported performance of screening CBE in > or =90% of women were evaluated using logistic regression. Fifty-one percent of physicians reported that they perform regular CBE on > or =90% of their patients, although the proportion varied across specialty type. Beliefs about the benefit of CBE were positive and similar across specialties. Twelve percent of male physicians, but no female physicians, reported that women's embarrassment affected their use of screening CBE. In a multivariate model, male gender, family practice specialty, and the perception of patient embarrassment were all associated with lower reported rates of performing regular CBE (p < 0.05). Work to increase the performance of CBE should consider the role of male physician embarrassment and family physician training. Ways to facilitate delivery of preventive care and factors influencing the women themselves may also be important to increased use of CBE.

Aged↗
PubMed2005

A model-based comparison of breast cancer screening strategies: mammograms and clinical breast examinations.

In screening for secondary prevention of breast cancer, clinical breast examination (CBE) combined with mammography may improve overall screening sensitivity compared with mammography alone. A systematic evaluation of the relative expenses and projected benefit of combining these two screening modalities is not presently available. We addressed this issue using a microsimulation model incorporating age-specific preclinical duration of the disease, age-specific sensitivities of the two modalities, age-specific incidence of the disease, screening strategy, and competing causes of mortality. We examined a total of 48 screening strategies, depending on the age range, the examination interval, and whether mammography or CBE is given at every one or two exam. Our results indicate that a biennial mammography can be cost-effective if coupled with annual CBE. For each screening interval and starting age, giving mammography every two exams and CBE at every exam has the lowest marginal cost per year of quality-adjusted life saved, whereas giving both at every exam has the highest. Comparing annual mammography and CBE to biennial mammography and annual CBE from 50 to 79, the total cost was reduced by 35%, whereas the marginal quality-adjusted life years only decreased by 12%. Similar reductions are observed for other starting ages. It is cost-effective to have a biennial mammography if coupled with an annual CBE. Annual mammography combined with CBE every 6 months will lead to a 41% increase in the quality-adjusted life years compared with annual mammography and CBE from 50 to 79, whereas the total cost increases by 30%.

Adult↗
PubMed1986

An overview of species differences in the effects of a water extract of cotton bract on isolated airway smooth muscle, and effects of E. coli lipopolysaccharide.

Our laboratory has been comparing the activity of a water extract of cotton bract (CBE) with the isolated trachealis smooth muscle of the dog, guinea pig, and cat. CBE induced contractions that were not mediated by 5-hydroxytryptamine (5-HT), histamine, or muscarinic receptors. The active agent(s) in CBE was dialyzable (less than 14,000 molecular weight), and substantial activity was retained after low-temperature ashing. CBE potentiated contractions of dog trachealis to histamine and 5-HT and relaxation responses to isoproterenol, whereas it had no effect on responses to methacholine and KCl. In the guinea pig trachealis, CBE reduced responsiveness to KCl, potentiated relaxations to adenosine and ATP, and did not alter the responses to the remaining agents. Responses of cat trachealis to KCl and isoproterenol were potentiated by CBE, while those to 5-HT were unaffected. Neurogenic cholinergic contractile responses were potentiated by CBE in the trachealis of the dog, but not of the guinea pig, while neurogenic relaxations were potentiated by CBE in guinea pig trachealis but not in the dog trachealis. There are thus marked species differences in the acute effects of CBE on airway smooth muscle. Due to recent interest in the possible involvement of bacterial endotoxins in the etiology of byssinosis, we examined the effects of E. coli lipopolysaccharide (LPS) in guinea pig trachealis. An initial examination revealed that LPS potentiated responses to histamine, but not those to methacholine and isoproterenol. This effect vanished upon a second appraisal with a different batch of LPS. The effect of LPS in airway smooth muscle is thus, at present, equivocal.

Airway Resistance↗