Binary endocardial appearance for Fabry disease diagnosis: a systematic review and meta-analysis

Objective

This study aimed to determine the performance of the endocardial binary appearance (binary sign [BS]) on echocardiography for Fabry-Anderson disease (FD) diagnosis.

Methods

A diagnostic systematic review was performed, which included studies with >20 patients selected, with enough reported data to compute the 2 × 2 tables, and with a BS evaluation against a genetic test. Evidence was searched up to October 4, 2020, in the following databases: PubMed, Scopus, EMBASE, and Web of Science. The risk of bias was evaluated using the Quality Assessment of Diagnostic Accuracy Studies 2 tool and certain evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach.

Results

Four studies were included in the systematic review. All studies were cross-sectional that included 524 patients that compared the BS vs. the alpha-galactosidase-A and/or genetic test, alpha-galactosidase-A and globotriaosylceramide isoform, and genetic test alone. The BS was found to have a sensitivity of 41% (confidence interval [CI] 95% = 17–71) and specificity of 91% (CI 95% = 60–99) and area under the curve of 0.71 (CI 95% = 0.64–0.78) for diagnostic of FD, with a certain of evidence low.

Conclusion

The BS has a good performance in confirming the diagnosis of FD, but not for screening. However, the evidence had low certainty, thus future studies could modify these results.

Funding Acknowledgement

Type of funding sources: None.

Uncommon tumors in multiple endocrine neoplasia (MEN) type 1: Do they have a relationship with the prognosis of these patients?

INTRODUCTION

The prognosis of MEN 1 patients is not only determined by pancreatic disease; it is also related to other uncommon tumors. The objective of this study is to analyze the tumors associated with MEN 1 outside the classic triad and to investigate their relationship with mortality.

MATERIALS AND METHODS

One hundred and five MEN 1 patients were studied in a tertiary referral hospital (1980-2019).

RESULTS

With a follow-up of 11 ± 4 years, seven patients died (8%), four as a consequence MEN syndrome. Thirty-three percent had adrenal gland tumors. One patient died of adrenal cancer. Eight percent presented with a neuroendocrine thoracic neoplasm, and one patient died. Another patient died due to cutaneous T-cell lymphoma. A further patient died because of a gastrinoma with liver metastasis.

CONCLUSIONS

To conclude, 75% of MEN-related deaths were the result of an uncommon pathology, and we, therefore, recommend that these tumors should be taken into account in the screening and follow-up of these patients.

Knowledge of tuberculosis and vaccine trial preparedness in Lima, Peru

SETTING

A safe, effective vaccine would improve tuberculosis (TB) control worldwide. Extensive community engagement will be essential to ensure the interest and participation of populations at highest risk.

OBJECTIVE/METHOD

To inform the potential implementation of efficacy studies, we assessed TB knowledge, attitudes towards licensed vaccines and willingness to participate in future TB vaccine efficacy trials among 262 household contacts of 79 recently diagnosed pulmonary TB cases in Lima, Peru.

RESULTS

Overall knowledge of TB was low. Only 41.6% of household contacts perceived themselves as being at high risk of acquiring TB. Slightly above half (54.2%) indicated willingness to participate in a TB vaccine trial. After clustered analysis adjusting for homogeneity among families, willingness to enroll was associated with belief that receiving all recommended vaccinations is important (adjusted OR [aOR] 3.28, P = 0.016), desire to know more about TB risk factors and clinical trials (aOR 2.60, P = 0.004), older age (aOR 1.02, P = 0.027) and TB knowledge (aOR 0.05, P = 0.039).

CONCLUSION

Barriers to participation in TB vaccine trials exist among individuals at high risk for TB. Targeted education about TB risk factors, TB transmission and education about the clinical trial process will be critical for laying the groundwork for future vaccine trials.

Lubricant use among men who have sex with men reporting receptive anal intercourse in Peru: implications for rectal microbicides as an HIV prevention strategy

This study assessed lubricant use during receptive anal intercourse (RAI) among Peruvian men who have sex with men (MSM) and willingness to use a hypothetical rectal microbicide (RM) formulated as a lubricant to prevent HIV infection. Data were collected from 843 Peruvian MSM for the 2008 HIV Sentinel Surveillance using a computerized self-interview. Half of the participants reported using a lubricant with their last sex partner during RAI, while 77% were willing to use a lubricant to prevent HIV transmission. Lubricant use with last sex partner was significantly associated with unprotected RAI (odds ratio [OR] 1.59, 95% confidence interval [CI], 1.23, 2.05; P < 0.001) and willingness to use a future lubricant RM (OR 1.56, 95% CI: 1.24, 1.95; P < 0.001). This study provides information on the behaviours associated with lubricant use and non-use among MSM practicing RAI in Peru that should inform future RM studies in Peru and other Latin American countries.

Role of 5-HT2A, 5-HT4 and 5-HT7 receptors in the antigen-induced airway hyperresponsiveness in guinea-pigs

BACKGROUND

A possible role of 5-hydroxytryptamine (5-HT) in the origin of antigen-induced airway hyperresponsiveness (AI-AHR) has been scarcely investigated.

OBJECTIVE

To explore the participation of different 5-HT receptors in the development of AI-AHR in guinea-pigs.

METHODS

Lung resistance was measured in anaesthetized guinea-pigs sensitized to ovalbumin (OVA). Dose-response curves to intravenous (i.v.) acetylcholine (ACh) were performed before and 1 h after antigenic challenge and expressed as the 200% provocative dose (PD(200)). Organ bath experiments, confocal microscopy and RT-PCR were additionally used. The 5-HT content in lung homogenates was measured by HPLC.

RESULTS

Antigenic challenge significantly decreased PD(200), indicating the development of AI-AHR. This hyperresponsiveness was abolished by a combination of methiothepin (5-HT(1)/5-HT(2)/5-HT(5)/5-HT(6)/5-HT(7) receptors antagonist) and tropisetron (5-HT(3)/5-HT(4) antagonist). Other 5-HT receptor antagonists showed three different patterns of response. Firstly, WAY100135 (5-HT(1A) antagonist) and ondansetron (5-HT(3) antagonist) did not modify the AI-AHR. Secondly, SB269970 (5-HT(7) antagonist), GR113808 (5-HT(4) antagonist), tropisetron or methiothepin abolished the AI-AHR. Thirdly, ketanserin (5-HT(2A) antagonist) produced airway hyporresponsiveness. Animals with bilateral vagotomy did not develop AI-AHR. Experiments in tracheal rings showed that pre-incubation with LP44 or cisapride (agonists of 5-HT(7) and 5-HT(4) receptors, respectively) induced a significant increase of the cholinergic contractile response to the electrical field stimulation. In sensitized lung parenchyma strips, ketanserin diminished the contractile responses to ACh. Sensitization was associated with a ninefold increase in the 5-HT content of lung homogenates. Confocal microscopy showed that sensitization enhanced the immunolabelling and co-localization of nicotinic receptor and 5-HT in airway epithelium, probably located in pulmonary neuroendocrine cells (PNECs). RT-PCR demonstrated that neither sensitization nor antigen challenge modified the 5-HT(2A) receptor mRNA levels.

CONCLUSIONS

Our results suggested that 5-HT was involved in the development of AI-AHR to ACh in guinea-pigs. Specifically, 5-HT(2A), 5-HT(4) and 5-HT(7) receptors seem to be particularly involved in this phenomenon. Participation of 5-HT might probably be favoured by the enhancement of the PNECs 5-HT content observed after sensitization.

Staphylococcal infections in rabbit does on two industrial farms

The main reasons for culling adult rabbit does on two Spanish rabbit farms were investigated for a year. The most important conditions were mastitis (33.3 per cent), followed by subcutaneous abscesses (9.9 per cent) and pyometra (8.7 per cent). Staphylococcus aureus infections were the most severe problem, the organism being isolated from 69.2 per cent of infected animals. Pasteurella species were more prevalent in cases of pyometra and pneumonia. Two strains of S aureus were identified by using polymorphism of the coagulase gene as the criterion. One of these strains was responsible for the majority of the staphylococcal infections and was isolated from several pathological processes.

[Preliminary study on efficacy and tolerance of a "coupage" of olive oil in patients with chronic kidney disease. Nutritonal evaluation]

The discrepancies among data reported by using olive oil (OO) in humans appear to be due to the great differences between the different OO used. Based on structure/function relationships we have chemically optimized an OO through the rational mixture ("coupage") of several Spanish extra virgin olive oils (methodology "oHo"). Patients with chronic kidney disease (CKD) develop a progressive picture of malnutrition and inflammation that lead them to an elevated risk of cardiovascular disease. In a pilot, randomised trial the nutritional efficacy and safety of "oHo" were evaluated in 32 patients (mean age 60,8 +/- 13,2 years old; 16 women) with CKD (KDIGO stages 4-5) at predialysis. After a 7 days wash out for statins and ACE inhibitors 19 patients had "oHo" at doses of 60 mL/day (20 mL t.i.d) for 30 consecutive days, whilst 13 patients remain as a control group without "oHo". At the end of the study only patients having "oHo" showed significant increases of serum albumin (p<0.05) and not significant increases of total proteins, weight, and BMI. Total cholesterol (p<0.05) and HDL-cholesterol (p<0.01) increased with "oHo". The number of cases with pathologic HOMA-IR in the control group increased from 1 to 2 patients whilst in the "oHo" group decreased from 2 to none. No significant changes of minerals, arterial pressure, hemoglobin, and other parameters related to CKD were seen. After a 30 days follow-up in the "oHo" group all parameters came back to basal ones, excepting for blood pressure that significantly decreased (p<0,05). Tolerance was excellent and constipation significantly diminished (p<0,001) in the "oHo" group. Of importance, none of these biological changes were seen in regular consumers of other conventional olive oils (control group). These intriguing results, seen by the first time, appear to partially satisfy the recent claims ("reverse epidemiology") about the need of a more correct nutrition in CKD patients. However, these data need to be proved in more larger trials as well as in CKD patients under dialysis with harder inflammatory/malnutrition conditions.

Genotypic characterization of Staphylococcus aureus strains isolated from rabbit lesions

Since staphylococcal infections are the main pathological problem in rabbit does, the objective of this study was to characterize epidemiologically Staphylococcus aureus isolates from different lesion types in rabbits. Using 3 genetic markers (coagulase, staphylococcal protein A and clumping factor B genes), 22 different genotypes were identified among 301 isolates recovered from 259 rabbit does with 10 different kinds of chronic purulent lesions. These infected rabbits were obtained from 30 herds located in the Valencia province on the Spanish Mediterranean coast. The most frequent genotype was designated A1/II1/delta (coa/spa/clfB combination genotype) and represented 70.76% of the isolates. Although most genotypes were previously identified in other countries, novel types were also documented. No specificity between genotypes and nature of the pathologic process could be identified. After genetic comparison between strains from different origins, the results may suggest that rabbit, bovine and human S. aureus isolates are not clonally related, suggesting that specific host-dependent pathogenic factors may have evolved independently in these species. These differences indicate that a rational and effective strategy to control infections caused by rabbit-specific isolates may be advantageous.

Pneumatosis cystoides intestinalis in a rabbit doe (Oryctolagus cuniculus)

Pneumatosis cystoides intestinalis (PCI) is an infrequent condition of animals characterized by the existence of numerous thin-walled, gas-filled cystic structures within the intestinal wall and adjacent lymph nodes. Microscopically, the cystic structures appear to be dilated lymphatics located in the lamina propria, submucosa, muscularis, subserosa, mesentery, and mesenteric lymph nodes. This report describes a case of pneumatosis cystoides intestinalis in a rabbit doe from an organic farm where 20 rabbit does were fed ad libitum with a natural diet consisting of whole barley, pea beans, alfalfa hay, and a pelleted vitamin-mineral blend. A combination of nutritional, bacterial, and other factors are hypothesized as possible predisposing factors in the development of PCI.

Differences between inhaled and intravenous bronchial challenge to detect O(3)-induced hyperresponsiveness

Ozone (O(3))-induced airway hyperresponsiveness in laboratory animals is usually demonstrated through dose-response curves with inhaled or intravenous bronchoconstrictor agonists. However, comparability of these two routes has not been well documented. Thus guinea pig airway responsiveness to ACh and histamine was evaluated 16-18 h after O(3) (3 parts/million, 1 h) or air exposure by two plethysmographic methods (spontaneously breathing and mechanically ventilated) and by two administration routes (inhalatory or intravenous). We found that O(3) caused airway hyperresponsiveness to intravenous, but not to inhaled, agonists, independent of the plethysmographic method used. Suitability of the inhalatory route to detect airway hyperresponsiveness was corroborated with inhaled ACh after an antigen challenge or extending O(3) exposure to 3 h. Acetylcholinesterase activity was not modified after O(3) exposure in lung homogenates and blood samples. Thus inhaled agonists were less effective to reveal the airway hyperresponsiveness after an acute O(3) exposure than intravenous ones, at least for the 1-h exposure to 3 parts/million, and this difference seems not to be related to an O(3)-induced inhibition of the acetylcholinesterase activity.

[Abdominal compartment syndrome]

French physicians dealing with abdominal emergencies are not very familiar with the abdominal compartment syndrome (ACS). Increased abdominal pressure has deleterious consequences on local (intestine, liver, kidney) circulation, leading to death in the absence of correct treatment. Abdominal trauma and ruptured aortic aneurism are the main causes of ACS. Clinical presentation may be misleading: respiratory failure, oliguria or circulatory symptoms are often predominant. Abdominal palpation is inefficient for evaluating intra-abdominal pressure (IAP); only measurement of cystic pressure allows precise evaluation of IAP. Abdominal decompression is the treatment of choice. It must be performed as soon as IAP exceeds 25 mmHg. The procedure may be risky with a high incidence of severe complications when ischaemic territories are reperfused. Recent data underline the importance of compensation of hypovolemia before decompression. Abdominal closure may necessitate various techniques (aponevrotomy, Bogota bags, etc.). At any rate, IAP must remain low at the end of the procedure. In case of suspicion of ACS, early measurement of IAP is mandatory. If pressure is over 25 mmHg, a decompressive procedure must be initiated.

Identification of mechanisms involved in the acute airway toxicity induced by parathion

Organophosphates are still widely used worldwide and cause thousands of intoxications every year. In this work we investigated the mechanisms of parathion (Pth) airway toxicity, using biochemical and functional approaches. A plethysmographic technique for unrestrained guinea pigs was used to analyze Pth-induced modifications of airway mechanics and responsiveness to acetylcholine (ACh: 0.1-3.2 mg/ml, 2-min inhalation each dose). The isolated perfused rabbit lung preparation was used to study the acute effects of Pth on airway responsiveness to ACh (10(-8)-10(-3) M), histamine (10(-8)-10(-3) M) and substance P (10(-10)-10(-6) M), pulmonary acetylcholinesterase inhibition and cytochrome P450 (P450) activity, and their modifications with previous administration of Pth (1 mg/kg s.c. daily, 7 days). We found that: (1) In guinea pigs Pth (3.2-17 mg/kg i.p.) produced a dose-dependent increase in a lung resistance index (iRL), which was greatly reverted (approximately 50%) by salbutamol (2 mg/ml, 2-min inhalation, or 10 microg/kg i.p.). This salbutamol effect was transient (5-10 min), suggesting that this bronchodilator triggered additional obstructive mechanisms. (2) Pth increased the water content in lung parenchyma samples, but not in trachea or bronchi, and augmented the respiratory secretions measured through monosaccharide content in bronchoalveolar lavage. (3) The increase in iRL was greater in female animals, probably due to a higher P450 basal activity, and completely blocked by pharmacological inhibition of P450 with piperonyl butoxide (500 mg/kg i.p.). (4) In male guinea pigs a subclinical dose of Pth (10 mg/kg i.p.) induced airway hyperresponsiveness to ACh. In isolated perfused rabbit lung Pth (10(-6) M) produced airway hyperresponsiveness to ACh and histamine, the latter prevented by atropine (10(-5) M). (5) Repetitive exposure to subclinical doses (1 mg/kg s.c.) of Pth during 1 week caused approximately 80% inhibition of P450 activity in rabbits, which was not enough, however, to prevent the functional manifestation of Pth toxicity in the airways.

Interactions between cytochrome P-450 activities and ozone-induced modulatory effects on endothelial permeability in rabbit lungs: influence of gender

The effects of rabbit exposure to ozone (O(3)) (0.4 ppm for 4 h) on two different cytochrome P-450 (CYP450)-dependent activities were investigated. In turn, the role of CYP450 in the inhibitory effect of O(3) on acetylcholine (ACh)-evoked increase in endothelial permeability was also assessed. Immediately after the period of exposure, rabbits of both sexes were sacrificed and their lungs were extracted. Some lungs were used for preparation of microsomes and measurement of 7-ethoxyresorufin O-deethylase (EROD) and parathion oxidase activities. Other rabbit lungs were isolated and recirculatingly blood-free perfused. Arterial, venous pressures, and lung weight were continuously recorded. Capillary pressure was measured by applying the double occlusion method. Capillary filtration coefficient (K(f,c)) was evaluated by measuring the amount of fluid filtering through the endothelium when vascular pressures were suddenly increased. Dose-response curves to ACh were constructed in air- or O(3)-exposed rabbits. Some animals were pretreated with piperonyl butoxide (PBO), a well-known inhibitor of CYP450. O(3) significantly reduced both EROD and parathion oxidase lung microsomal activities in females, while it had no effect in males. Exposure to O(3) strongly inhibited the ACh-induced increase in K(f,c). Pretreatment with PBO reversed the modulatory effect of O(3) on endothelial permeability in male rabbits, but not in females. It was concluded (1) that inhibition of 2 different CYP450-dependent activities after exposure to 0.4 ppm O(3) for 4 h appears to be a gender-dependent phenomenon, and (2) that CYP450 is probably involved in the O(3)-evoked inhibitory mechanism against ACh-induced increase in endothelial permeability, but only in males.

Possible venous argon gas embolism complicating argon gas enhanced coagulation during liver surgery

We report a case of a major venous argon embolism during argon beam coagulation of a liver biopsy. The essential signs were an abrupt reduction in end-tidal carbon dioxide partial pressure, in SpO2 and in systolic arterial pressure, at the time of coagulation. Spontaneous recovery was observed within 10 min. Precautions in respect of usage are highlighted.

Hemispheric differences in variability of fissural patterns in parasylvian and cingulate regions of human brains

We have determined different patterns of fissurization in Broca's area, the gyrus of Heschl, the planum temporale, the inferior parietal lobe, and the cingulate sulcus. Such patterns were asymmetrically distributed, indicating increased folding on the left side in most cases. More folding can sometimes be related to a larger cortical area, resulting in increased processing capacities in the respective brain region. Furthermore, the brain regions associated with the asymmetrical sulci are involved in lateralized functions. Of special interest are the asymmetries observed in regions corresponding to the inferior parietal lobe (the accessory postcentral sulcus and the intraparietal sulcus), which, according to recent studies, is involved in linguistic working memory. We did not detect a tendency of distinct fissurization patterns in a given brain region to be associated with specific patterns in other fissures, indicating that the different fissure types develop independently in each brain region and can therefore be determined by local processes. These descriptions are of relevance to imaging studies that intend to establish correspondences between gross morphology and functional parameters such as behavior and brain activation.

Comparison of ozone-induced effects on lung mechanics and hemodynamics in the rabbit

The effects of rabbit exposure to ozone (O3)(0.4 ppm for 4 h) on pulmonary mechanical properties and hemodynamics have been investigated on the isolated perfused lung model. Tracheal pressure, airflow, and tidal volume were measured in order to calculate lung resistance (RL) and dynamic compliance (Cdyn). Using the arterial/venous/double occlusion method, the total pressure gradient (deltaPT) was partitioned into four components (arterial, pre-, postcapillary and venous). Dose-response curves to acetylcholine (ACh), substance P (SP), and histamine were constructed in lungs isolated from rabbits immediately or 48 h after air or O3 exposure O3 induced a significant increase in the baseline value of deltaPt, more markedly 48 h after the exposure. Immediately after the exposure, O3 partly inhibited the ACh-, SP-, and histamine-induced decreases in Cdyn and increases in RL. This inhibitory effect was still in part present 48 h after O3 treatment. In the groups studied immediately after exposure, O3 did not significantly modify the ACh-, SP-, and histamine-induced vasoconstriction. Forty-eight hours after exposure, O3 induced a contractile response to ACh and SP in the arterial segment but decreased the response to histamine. We conclude that O3 can induce direct vascular constriction. Directly, but also 48 h after exposure, O3 can inhibit the ACh-, SP-, and histamine-induced changes in lung mechanical properties. Ozone can also induce some changes in the intensity and in the location of the vascular responses to ACh, SP, and histamine.

Effect of different ozone concentrations on the neurogenic contraction and relaxation of guinea pig airways

Prejunctional and postjunctional effects of several ozone (O3) concentrations, including those found in highly polluted cities, were evaluated in guinea pig airways. Animals bred in O3-free conditions were exposed to air or O3 (0.3, 0.6 or 1.2 ppm) during 4 h, and studied 16-18 h later. Tracheal and bronchial rings were studied in organ baths. Electrical field stimulation (EFS) (100 V, 2 ms, 10 s) was given at increasing frequencies (0.25-16 Hz). Some tissues received atropine (2 microM) and/or propranolol (10 microM). Concentration-response curves to carbachol, isoproterenol, nitroprusside, and substance P were constructed. In tracheas, almost all O3 concentrations decreased the relaxation at low EFS frequencies, but had no effect on the propranolol-resistant (i-NANC) relaxation, suggesting that only adrenergic relaxation was affected. This was a prejunctional effect, since O3 did not modify the responses to isoproterenol. Relaxation induced by a nitric oxide (NO) donor, nitroprusside, was not affected by O3, which agrees with the lack of O3-effect on i-NANC system. O3 did not modify the EFS-induced e-NANC contraction in atropine-treated bronchi, nor the contraction caused by exogenous substance P. By contrast, in bronchi without atropine, 1.2 ppm O3 increased the e-NANC contraction induced by the highest EFS (16 Hz). O3 increased the maximum responses to carbachol in tracheas (1.2 ppm) and bronchi (0.6 and 1.2 ppm). In conclusion, we found that: a) O3 decreased adrenergic relaxation in guinea pig tracheas at low EFS frequencies through a prejunctional alteration; b) O3 did not modify the i-NANC relaxation in tracheas, at least the NO-mediated; c) O3 added a cholinergic component to the bronchial slow-phase (e-NANC) contraction evoked by EFS; and d) O3 enhanced the cholinergic responses in trachea and bronchi by a postjunctional mechanism.

Ozone-induced stimulation of pulmonary sympathetic fibers: a protective mechanism against edema

Tropospheric ozone exerts well-described toxic effects on the respiratory tract. Less documented, by contrast, is the ability of ozone to induce protective mechanisms against agents that are toxic to the lungs. In particular, interactions between ozone and the sympathetic nervous system have never been considered. Using a model of permeability edema in isolated perfused rabbit lungs, we report here that, immediately after exposure of rabbits to 0.4 ppm ozone for 4 hr, the pulmonary microvascular responses to acetylcholine and substance P are completely blocked. Several lines of evidence, including partial inhibition of the ozone-induced protective effect by several drugs (alpha2- and beta-adrenergic antagonists, neuropeptide Y antagonist, guanethidine), measured levels of released catecholamines in blood and urine and the in vitro response of isolated lungs exposed to 0.4 ppm ozone all seem to suggest that ozone can stimulate pulmonary adrenergic fibers and induce the local release of catecholamines and neuropeptide Y, this resulting in transient protection against pulmonary edema. We also showed that, 48 hr after the exposure, ozone increased the baseline microvascular permeability and the response to low concentrations of acetylcholine.

Ozone at high-pollution urban levels causes airway hyperresponsiveness to substance P but not to other agonists

Ozone (O(3)) causes airway hyperresponsiveness, but few studies have evaluated this effect at urban concentrations. In this work dose-response curves to intravenous acetylcholine, histamine or substance P were performed in guinea pigs with or without previous exposure to O(3) (0.15, 0.3, 0.6 or 1.2 ppm for 4 h, 16-18 h before the studies). We found airway hyperresponsiveness to histamine, but not to acetylcholine, only after 1.2 ppm O(3). By contrast, airway hyperresponsiveness to substance P was developed at O(3) levels encountered in highly-polluted cities (0.3 ppm). These results suggest that excitatory non-adrenergic non-cholinergic responses could be affected by air pollution, and that substance P is a useful pharmacological tool for evaluating the airway hyperresponsiveness induced by low O(3) concentrations.

Interactions between acetylcholine and substance P effects on lung mechanics in the rabbit

The pharmacological mechanisms involved in the acetylcholine (ACh)- and substance P (SP)-induced changes in pulmonary mechanics were studied in isolated perfused rabbit lungs. Tracheal pressure (Ptr) and airflow were measured by a Fleisch pneumotachograph and pressure transducers. Air volume, lung resistance (RL) and dynamic compliance (Cdyn) were calculated. ACh induced a dose-dependent increase in Ptr and RL, and a decrease in Cdyn. These effects were strongly prevented by atropine, and partly by SR140333, a neurokinin NK1 receptor antagonist; SR48968, a neurokinin NK2 receptor antagonist; indomethacin and antihistaminics. Ketanserin had no significant protective effect against ACh. SP also induced concentration-dependent increases in RL and decreases in Cdyn. SR140333 and atropine strongly inhibited the effects of SP, while ketanserin, SR48968, antihistaminics and indomethacin did not protect the lungs against this drug. 5-hydroxytryptamine induced no significant change in lung mechanic parameters. Cumulative concentrations of histamine increased RL and decreased Cdyn. We conclude that ACh-induced changes in lung resistance and compliance are in part mediated by a direct effect on airway smooth muscle and in part by the stimulation of C fibers, by the release of histamine from mast cells and by the synthesis of arachidonic acid metabolites. In turn, the effects of SP on lung mechanics are partly due to cholinergic activation.

Inhaled Bordetella pertussis vaccine decreases airway responsiveness in guinea pigs

Bordetella pertussis (BP) has been used as adjuvant for experimental animal immunization, but its effects on airway responsiveness are uncertain. Three groups of guinea pigs were used: animals with a single exposure to inhaled BP vaccine (strain 134, total dose 1.24 x 10(12) germs), animals submitted to a sensitization procedure through inhalation of ovalbumin plus BP, and healthy control animals. Four weeks after inhalation of BP or after the beginning of sensitization, dose- or concentration-response curves to histamine were constructed in vivo and in vitro (tracheal and parenchymal preparations). We found that BP alone produced lower responses to histamine than control guinea pigs in vivo (insufflation pressure, p = 0.0003) and in tracheal tissues (p = 0.04), but not in parenchymal preparations. Sensitization did not modify the responsiveness compared with their respective controls. These results suggest that some BP component(s), probably pertussis toxin, causes a long lasting airway hyporesponsiveness in guinea pigs.

Effect of ozone exposure on antigen-induced airway hyperresponsiveness in guinea pigs

Airway hyperresponsiveness can be induced by several stimuli including antigen and ozone, both of which may be present in the air of polluted cities. Though the effect of ozone on the bronchoconstrictor response to antigen has been well described, the combined effect of these stimuli on airway hyperresponsiveness has not yet been studied. Sensitized guinea pigs with or without ozone exposure for 1 h at 3 ppm, 18 h prior to study, were challenged with a dose-response curve to histamine (0.01-1.8 micrograms/kg, iv) followed by an antigen challenge (ovalbumin, 50 micrograms/kg, iv), and then by a second histamine dose-response curve 1 h later. Airway responses were measured as the increase in pulmonary insufflation pressure. In sensitized guinea pigs, the histamine ED50 significantly decreased after antigen challenge, demonstrating the development of airway hyperresponsiveness. Sensitized guinea pigs exposed to ozone showed airway hyperresponsiveness to histamine when compared with nonexposed animals, and such hyperresponsiveness was further enhanced after antigen challenge. We conclude that in this guinea pig model of acute allergic bronchoconstriction both antigen challenge and ozone induce airway hyperresponsiveness, while ozone exposure does not modify the development of antigen-induced hyperresponsiveness.

O3-induced airway hyperresponsiveness to noncholinergic system and other stimuli

The effect of O3 exposure (3 ppm, 1 h) on the in vivo and in vitro airway responsiveness, as well as the changes in cell contents in bronchoalveolar lavage (BAL) fluid, were evaluated 16-18 h after O3 exposure in sensitized and nonsensitized male guinea pigs. The sensitization procedure was performed through repeated inhalation of ovalbumin for 3 wk. Increase in pulmonary insufflation pressure produced by the excitatory nonadrenergic noncholinergic (eNANC) system, histamine, and antigen were assessed in in vivo conditions, whereas airway responsiveness to histamine and substance P was evaluated in in vitro conditions by use of tracheal chains with or without epithelium and lung parenchymal strips. We found that O3 exposure 1) increased the neutrophil content in BAL fluids in both sensitized and nonsensitized guinea pigs, 2) caused hyperresponsiveness to eNANC stimulation in nonsensitized guinea pigs (although combination of sensitization and O3 exposure paradoxically abolished the hyperresponsiveness to eNANC stimulation), 3) increased the in vivo bronchoconstrictor responses to histamine and antigen, 4) caused hyperresponsiveness to substance P in nonsensitized tracheae with or without epithelium and in sensitized tracheae with epithelium, 5) did not modify the responsiveness to histamine in tracheae with or without epithelium (and in addition, epithelium removal caused hyperresponsiveness to histamine even in those tracheae exposed to O3), and 6) produced hyperresponsiveness to histamine in lung parenchymal strips either from sensitized or nonsensitized guinea pigs.

Pharmacological characterization of mediators and vagal influence in the acute allergic bronchoconstriction in guinea pigs

The allergic bronchoconstriction in guinea pigs has been attributed mainly to the release of mast cell mediators. Histamine has been involved in the first minutes of the anaphylactic reaction and new-formed compounds in the subsequent response. In this asthma model the vagal influence has been sparsely investigated. In the present work we evaluated the pharmacological modification of the acute allergic bronchoconstrictor response in guinea pigs sensitized to ovalbumin through aerosol exposure. Pyrilamine (20 micrograms/kg), diethylcarbamazine (a lipoxygenase inhibitor, 10 mg/kg) and dexamethasone (4 mg/kg) each reduced the antigen-induced bronchoconstriction throughout the 30 min studied. Indomethacin (3.1 mg/kg) did not modify the response to the antigen. Atropine (2 mg/kg) plus bilateral vagotomy also diminished this response from 5 min onward. On the other hand, from 5 min ahead pyrilamine-resistant bronchoconstriction was partially inhibited by dexamethasone, and it was almost completely blocked during all of the response when atropine plus bilateral vagotomy were added to dexamethasone. Dipyridamole (an inhibitor of the adenosine uptake, 0.4 mg/kg) enhanced the bronchoconstriction, though this was significant only in the 2-5 min time-interval of the response. These results suggest that histamine and vagal influence play an important role in the whole response to antigen, that other mediators, probably leukotrienes, participate in this response from 5 min onward, and that adenosine could exert a potentiation effect on this response.