Principal Bronchus Research Articles

Endoscopic evaluation of bronchial morphology in rabbits

To evaluate bronchial morphology endoscopically in rabbits and develop a valid nomenclature for the endobronchial branching pattern. 10 mature New Zealand White rabbits. Flexible bronchoscopy was performed in rabbits anesthetized with isoflurane via nasal mask. Airways were systematically evaluated from the larynx to the terminal branches accessible with a 2.5-mm-outer diameter flexible endoscope. Airway branching patterns were identified and assessed for variation among subjects. Airways of all rabbits were readily examined with the 2.5-mm flexible endoscope. Laryngeal structure and function were normal in each rabbit, and airway branching patterns in all rabbits evaluated were identical. At the carina, branching into left and right principal bronchi was evident. The left principal bronchus divided immediately into the left cranial and left caudal lobar bronchi. The left cranial lobe bronchus further divided into dorsal and ventral segmental bronchi. The left caudal lobe bronchus gave rise to branches originating dorsally, ventrally, and medially before continuing caudally. The right principal bronchus divided into the right cranial, right middle, and accessory lobar bronchi and continued distally as the right caudal lobar bronchus. The right cranial lobe bronchus also divided into dorsal and ventral segmental bronchi, and the right caudal lobe bronchus had branches that originated dorsally, ventrally, and medially. Definition of a standard nomenclature for airway branching in rabbits will allow precise localization of disease in clinical cases and accurate collection of airway samples in clinical and scientific evaluations.

Emergency resection of a carinal adenoma

A man aged 46 developed acute stridor and fibreoptic bronchoscopy showed a large pedunculated mass at the carina. The right main bronchus was completely obstructed and the left main bronchus about 50% obstructed. Biopsies were non-diagnostic. CT showed the mass to occupy the distal tracheal lumen and there was a large posterior extrabronchial component (Figure 1). The posterior tracheal wall bisected the tumour mass. Endobronchial resection, attempted via a rigid bronchoscope, caused moderate bleeding into the distal airways and the procedure was terminated. Over the next two days ventilation became increasingly difficult, high inflation pressures being required to achieve satisfactory tidal volumes and adequate oxygenation. A decision was made to attempt carinal resection through a right thoracotomy; on left lateral positioning, however, he could not be ventilated satisfactorily and inflation pressures and pCO2 rose. Therefore cardiopulmonary bypass was established by femoro-atrial cannulation. After median sternotomy the superior mediastinal structures were dissected out and the anterior pericardium was mobilized as a pedicle with a broad base of attachment to the aortic arch. The trachea was incised just above the carina to expose the endotracheal tumour (Figure 2). The posterior component arising from the posterior tracheal wall and the adjacent main bronchi was excised with a circumferential margin of normal tracheal wall. The pericardial flap was rotated to bring its serosal surface into the tracheal lumen, and was sutured to the margins of the resulting defect in the posterior wall of the trachea and principal bronchi. Completion bronchoscopy showed widely patent distal trachea and principal bronchi. Mechanical ventilation had to be continued for seven days because of non-cardiogenic pulmonary oedema. Three weeks postoperatively he underwent bronchoscopy and dilatation of a mild anastomotic stricture. After another four weeks he was discharged home. The final pathological diagnosis was pleomorphic adenoma with apparently complete resection. Over the ensuing four months he required three further tracheal dilatations, which were increasingly difficult. He then underwent permanent stenting of the left main bronchus and distal trachea with two Gianturco non-covered wire stents. 2 years later he had no stridor and was symptom-free.

Radiographic and computed tomographic evaluation of experimentally induced lung aspiration sites in dogs

This study was performed to radiographically examine the prevalence of aspiration sites and to evaluate their atomical correlation with the bronchial pattens. Ten healthy beagle dogs were repeatedly radiographed, at weekly intervals, in the left and right lateral, ventrodorsal (VD) and dorsoventral (DV) positions. Three mililiters of iohexol distilled with same volume of saline was infused into the tracheal inlet. Which lung lobe was aspirated was decided upon by the presence of a significant alveolar pattern due to the contrast medium. Alveolar patterns were identified at the left (100%) and right cranial lung lobes (77%) with the dogs in dependant lateral recumbency, at the right caudal lung lobe (71%) with the dogs in VD recumbency and at the right middle lung lobe (59%) with the dogs in DV recumbency, respectively. The anatomical correlation was evaluated by performing computed tomography. The right principal bronchus (165.8 ± 1.6°) was more straightly bifurcated than was the left principal bronchus (142.7 ± 1.8°, p < 0.01). In VD position, the right side lung had a greater opertunity to become aspirated. The ventrally positioned right middle lobar bronchial origin was more easily to be aspirated the other laterally positioned ones. We think that these anatomical characteristics can be one of the causes for aspiration pneumonia to occur more frequently in the right side lung.

ｒｔ‐ＰＡ認可後の急性期脳梗塞に対する急性期血行再建術の治療戦略

We investigated the treatment outcome of revascularization for acute ischemic stroke and reviewed therapeutic strategy of endovascular therapy and intravenous rt-PA therapy after the approval of rt-PA. We performed adaptive determination of revascularization using MRI (DWI/PWI) for all acute stage, and intravenous rt-PA therapy was performed only for confirmed cases in a principal bronchus artery in MRA.We took intravenous rt-PA therapy for cardioembolic MCA occlusion of less than 3 hours and performed endovascular treatment which were the brain blood vessel expansion technique that we used UK intraarterial injection or a balloon and stent for besides it. As for the treatment strategy of revascularization, that we perform the treatment that conformed to eligibility criteria of intravenous rt-PA therapy is recommended for future acute stage without receiving it for a case of less than 3 hours than the onset. In addition, it should be reviewed adaptation of brain endovascular treatment for the patient beyond three hours by evaluating cerebral circulation dynamics by imaging such as DWI/PWI MR. As for the revascularization, maintenance of early transportation organization of the local acute stroke patient and architecture of inside the hospital organization are important for acute stage after intravenous rt-PA therapy certification.

Computed Tomography of the Mediastinum of the Dog by a Six‐generation CT Scanner, Different Windows and Peroral and Intravenous Contrast Medium

The anatomical and clinical studies of computed tomography (CT) in the dog are still scarce. Particularly, there are few CT studies combining the use of rapid apparatus of the latest generation, the supply of contrast medium (digestive or intravenous) and the application of regional specific CT windows with different window width (WW) and window level (WL). The use of this CT methodology is particularly recommended in the evaluation of mediastinal masses, heart pathologies, etc. In this work the mediastinum of the dog was studied by using a sixth generation spiral CT scanner (Toshiba Ex Vision), belonging to the private Medical Institute of Radiology ‘Irion’ of Porto Alegre, Brazil. Four mixed‐breed mature dogs (4–6 years, 15–20 kg) were used, two males and two females. The dogs were anaesthetized and kept at a maximum inspiration when getting the images. Previously, the urografin® contrast had been injected by peroral and intravenous (cephalic vein) via. Dogs were placed in a stretcher in sternal recumbency. Different CT windows were applied in order to increase the quality of the images and to obtain detailed attenuation shades of the mediastinum organs: soft tissue window (WW 652; WL ‐34), pulmonary window (WW 928; WL ‐680) and mediastinal‐vascular window (WW 352; WL 220). The mediastinal space was studied craniocaudally from the level of the cranial cava vein, brachiocephalic trunk and left subclavian artery, to the caudal end of the lumbodiaphragmatic recess. The obtained images allowed a very good tomographic evidence of the great vessels, the heart, the thoracic portion of the trachea, the principal bronchi, the thoracic portion of the oesophagus, etc.

Effect of various thoracic radiographic projections on the appearance of selected thoracic viscera

To assess the effect of different radiographic projections on thoracic width, as well as position and visibility of the trachea, principal bronchi, cardiac silhouette, aorta, caudal vena cava (CVC) and oesophagus. Right lateral recumbency (RLR), left lateral recumbency (LLR), dorsoventral (DV) and ventrodorsal (VD) thoracic radiographs of 42 dogs were reviewed retrospectively. In 78 per cent of cases the thoracic width was significantly larger on the VD projection than on the DV projection. The angle of divergence formed by the principal bronchi was significantly larger on the VD projection than on the DV projection in 80 per cent of dogs. A cardiac silhouette bulge at 1 to 2 o'clock was apparent on the VD projection in 22 per cent of dogs but was never seen on DV projections. The descending aorta was more visible at the 4 to 5 o'clock cardiac silhouette level on the DV projection and laterally at the T8 level on LLR projections. The CVC was better seen on VD and LLR projections. The oesophagus was visible as a soft tissue opacity in LLR in large dogs with normal thoracic conformation in 35 per cent of cases. The DV projection appears to be more reliable for assessing the cardiac silhouette, the descending aorta and the angle of divergence of the principal bronchi. The VD projection should be considered for evaluating the CVC. LLR should be used for assessing the descending aorta and CVC.

Une cause inhabituelle de détresse respiratoire aiguë : l’aspergillose bronchique obstructive

We report the case of a 77-Year-old immunocompetent woman who required intensive care for acute dyspnea revealing complete atelectasia of the left lung related to an aspergillus mycelium plug blocking the principal bronchus. The clinical course was favorable after deobstruction by thermocoagulation and oral itraconazole given for six Months. The patient was free of parenchymatous or endobronchial sequelae. Adjuvant oral corticoid therapy was given temporarily during the second Month of treatment when signs of transition towards allergic aspergillosis developed. Four Months after discontinuing the antifungal treatment, the patient developed a new episode of acute dyspnea caused by atelectasia limited to the right lower lobe. Treatment by itraconazole was resumed and continued as long-term therapy. No recurrence has been observed for eighteen Months. The diagnostic and therapeutic problems raised by Aspergillus fumigatus are well known in the immunocompromised subject, but can also be encountered in the immunocompetent subject.

Morphological and embryological characteristics of bronchial arteries in the rat.

There have been no previous reports of detailed macroscopic findings of the bronchial arteries, the nutrial vessels of the lungs. Also, previously, very little was known about the developmental processes of the bronchial arteries in rats and other laboratory animals. In the present study, we dissected bronchial arteries of adult rats from their origin to the pulmonary hilus, and examined developmental processes of bronchial arteries in a series of rat embryos. We observed one right bronchial artery and one left bronchial artery. The right artery arose from the right highest intercostal artery, ran together with the right vagus nerve along the right side of the trachea and right principal bronchus and reached the pulmonary hilus. The left artery arose from the left internal thoracic artery, ran along the left vagus nerve on the ventral surface of the thoracic aorta, and reached the dorsal surface of the left principal bronchus. In a series of 12 to 20.5-day-old rat embryos, the right bronchial artery was clearly identified in 20.5, 18.5, and 16.5-day-old embryos. In a 15.5-day-old embryo, a vessel corresponding to the right bronchial artery was recognized within the capillary plexus extending along the right lateral surface of the bronchus. In ontogenetic development, there appears to be little difference in completion time of the extrapulmonary part of the bronchial arteries between humans and rats.

Endobronquial metastasis of a ductal carcinoma in a male

Breast cancer in male is uncommon and 60% of the cases are presented in advanced stadiums of the disease. Malignant pleural effusion is a frequent form of presentation of breast cancer in women, being uncommon in males. We describe the case of a malignant pleural effusion and metastatic endobronchial of a ductal carcinoma of breast in male.A fifty five years old male, non-smoker, without other pathological recards, consulted our hospital because of a medical profile of 1 month of evolution of dyspnea of effort and dry cough. In the physical examination he only emphasized a hypophonesis in left side of chest and an exofitc injury in the right nipple. The blood analysis detected a mild normocitic anaemia and an ESR of 76 mm/h. The radiology of the chest showed a massive left pleural effusion, that was confirmed subsequently in a thoracic computed tomography scan. A bronchoscopy was practiced finding a tumor in the left principal bronchus which obstructed the light of the lumen. At the same time a mammography was accomplished, showing a nodule in the right breast suggestive of carcinoma whose aspirative puncture was positive for infiltrating ductal carcinoma moderately differentiated. Also, the result of the endobrochial biopsy was compatible with metastatic ductal carcinoma of the breast. No other metastasis were detected. The patient began chemoterapy during 6 cycles, appreciated a symptomatic improvement and a partial response in the thoracic computed tomography scan. After 6 months of follow-up the patient stays stable and without symptoms.The basic study of a cancer of metastatic presentation, a clinic history, physical examination, general analysis with tumors markers and a chest X-ray must be included. If this study and anatomopatologic examination of the metastasis doesn’t guide us toward the primary tumor, most series recommend an additional study with an abdominal-pelvic computed tomography scan and a mammography in women. In males, prevalence of breast cancer is very low (less than 1%). In this case, we recommend a breast examination as an screening initial before any sophisticated explorations can be made.

Immunolocalization of aquaporin-8 in rat kidney, gastrointestinal tract, testis, and airways.

The purpose of this study was to determine the cellular and subcellular localization of aquaporin-8 (AQP8) in rat kidney and other organs by RT-PCR analyses and by immunoblotting and immunohistochemistry using peptide-derived rabbit antibodies to rat AQP8. RT-PCR and Southern blotting revealed the presence of AQP8 mRNA in all kidney zones. LLC-PK(1) cells transfected with a rat AQP8 construct exhibited strong labeling with the affinity-purified antibodies, whereas controls using cells transfected with the vector, but without the insert, were negative. The labeling was almost exclusively associated with intracellular vesicles. Immunoblotting of kidney membrane fractions revealed a predominant single band of 26-28 kDa. AQP8 immunoreactivity was mainly present in the cortex and outer stripe of the outer medulla. Sequential ultracentrifugation of rat kidney membrane revealed that AQP8 resides predominantly in intracellular vesicular fractions. Immunocytochemistry revealed modest labeling of proximal tubules and weak labeling of collecting ducts in cortex and medulla of rat kidney. The labeling was confined to cytoplasmic areas with no labeling of the brush border. Immunoblotting and RT-PCR/Southern blotting also revealed the presence of AQP8 protein and mRNA in rat liver, testis, epididymis, duodenum, jejunum, colon, and bronchi/trachea. Consistent with this, immunohistochemistry revealed AQP8 labeling in the hepatocytes and spermatogenic cells in testis and in the basal cells in ductus epididymis, trachea, and bronchial epithelia. Moreover, AQP8 labeling was observed in the myoepithelial cells in salivary, bronchial, and tracheal glands with no labeling of acini or ductal epithelial cells. AQP8 is also present in the surface epithelial cells in duodenum, jejunum, and colon. In conclusion, AQP8 is expressed at low levels in rat kidney proximal tubules and collecting ducts, and it is present in distinct cell types in liver, testis, epididymis, duodenum, jejunum, colon, trachea, and principal bronchi as well as in multiple glands, including salivary glands.

A Case of Pulmonary Carcinosarcoma which Metastasize to Pelvic Cavity After Left Pneumonectomy

Pulmonary carcinosarcoma(Sarcomatoid carcinoma of the lung) is a rare pulmonary malignancy, which is defined as having an admixture of both carcinomatous and sarcomatous components. Pulmonary carcinosarcoma occurs most frequently in males between 50 and 80 years of age. It predominantly affects the upper lobe and/or the principal bronchi, and is associated with a history of smoking. Here, we report a case of pulmonary carcinosarcoma with a left lobe atelectasis due to an endobronchial mass in a 56-year-old male. After a left pneumonectomy, the pathologic stage was IIb (). Four months later, an abdominal mass was observed and exploratory laparotomy revealed metastases of the pulmonary carcinosarcoma to the pelvic cavity.

Cellular expression of retinal dehydrogenase types 1 and 2: effects of vitamin A status on testis mRNA.

We examined expression of retinal dehydrogenase (RALDH) types 1 and 2 in liver and lung, and the effect of vitamin A status on testis expression by in situ hybridization. Liver expressed RALDH1 and RALDH2 only in stellate cells and hepatocytes, respectively. Lung expressed RALDH1 and RALDH2 throughout the epithelia of the airways, from the principal bronchi to the respiratory bronchiole. Vitamin A-sufficient rats expressed RALDH1 in spermatocytes, with less intense expression in spermatogonia and spermatids, and expressed RALDH2 in interstitial cells, spermatogonia, and spermatocytes. Neither Sertoli nor peritubular cells showed detectable RALDH1 or RALDH2 mRNA. Vitamin A deficiency produced a sevenfold increase in RALDH1 and a 70-fold decrease in RALDH2 mRNA in testis. In each case, the net change reflected extensive loss of germ cells, increased intensity of expression in residual germ cells, and expression in Sertoli and peritubular cells. Low-dose RA relatively early during vitamin A depletion supported spermatogenesis and affected expression of both RALDHs, but did not reinstate "vitamin A normal" expression patterns. These results show that: RALDH1 and RALDH2 have distinct mRNA expression patterns in multiple cell types in three vitamin A target tissues; RALDH expression occurs in cell types that express cellular retinol-binding protein and retinol dehydrogenase isozymes (except stellate cells, for which retinol dehydrogenase expression remains unknown); vitamin A deficiency and RA supplementation affects the loci and intensity of RALDH mRNAs in testis; and low-dose RA does not substitute completely for retinol. Overall, these data provide insight into the unique functions of RALDH1 and RALDH2 in retinoid metabolism.

Bronchial Arterial Devascularization. An Experimental Study in Pigs

Objective - The lungs have dual blood supply: The bronchial and the pulmonary circulation. The importance of bronchial circulation is disputed. The purpose of this study was to establish an experimental model to examine the importance of the bronchial artery. Design - Comparative porcine experimental study. The surgical technique was evaluated in group A (n = 9). Group B (n = 8) underwent left bronchial arterial devascularization. In group C (n = 9) the left principal bronchus was devascularized, transsected, and reanastomosed. In groups B and C bronchial mucosal blood flow was studied with laser-Doppler velocimetry. Devascularization was controlled by angiography at section, and specimens were examined with conventional histology and scanning electron microscopy. The right bronchus served as control. Results - In group B devascularization caused considerable, yet insignificant reduction in bronchial mucosal blood flow index (p = 0.1282) postoperatively, and after 1 week (p = 0.0678), insignificant histologic (p > 0.2) changes, and no scanning electron microscopy differences. In group C devascularization with bronchial transsection caused significant reduction in mucosal blood flow index (p = 0.0277) postoperatively and after 1 week (p = 0.0277), significant histologic changes (p = 0.0277), and insignificant (p = 0.069) changes in scanning electron microscopy. Conclusion - Bronchial arterial devascularization with transsection caused significant physiologic and morphologic changes, and a model with bronchial devascularization should include transsection.

The porcine bronchial artery: surgical and angiographic anatomy.

The pig is often used in experimental studies on the significance of bronchial artery circulation, but the anatomy of this artery is only poorly described. The purpose of this study was to improve the anatomical basis for experimental studies on the porcine bronchial artery circulation. The origin of the artery from the aorta is described in 32 pigs. Heart-lung blocks were perfused with saline and removed in 16 pigs, and the broncho-oesophageal orifice was identified and cannulated. In these 16 specimens the intrapulmonary ramification was studied by angiography, and the extrapulmonary distribution and supply area by injection of Evans Blue. The broncho-oesophageal artery originated from the aorta as a single trunk in 91%. Angiography showed that each principal bronchus was accompanied by 2 bronchial artery branches far into the lung parenchyma. The central branching pattern of the artery between the aorta and the principal bronchi was divided into 3 subtypes. Evans Blue showed communication with the whole mediastinum. The anatomical relations are described. It is concluded that the broncho-oesophageal artery divides to follow each bronchus with 2 bronchial branches. A nomenclature for these branches is suggested. The pig anatomy is suited for experimental investigations on the bronchial circulation.

Resultados del tratamiento quirúrgico del carcinoma broncopulmonar no microcítico en estadio III-A

To analyze results and survival after surgical treatment of various stage III-a subgroups. We reviewed 748 case histories of patients with non-small cell bronchopulmonary carcinoma between January 1970 and December 1991, selecting 121 patients who underwent resection of stage III-a tumors, according to the pathologist's report. Overall survival at 3, 5 and 10 years was 26, 16 and 12%, respectively. The subgroup with better response to treatment was that of patients with T-3 tumors (peripheral), N-0, with survival of 21% at five years. If peribronchial and/or hilar (N-1) nodes were affected, survival was slightly less (16%). If mediastinal adenopathy (N-2) was present, there were no survivors after 3 years. In this same T-3 group, but with neoplastic invasion of the pericardium, mediastinal pleura or principal bronchi, survival after 3 years was nil. The survival rates of peripheral T-3 patients undergoing block resections were 27, 20 and 17% at 3, 5 and 10 years, respectively, 16% at 2 years and 0% at 5, for those with extrapleural resection. Patients with the poorest response to treatment were those with mediastinal nodes (N-2), in whom survival was 17, 12 and 8% at 3, 5 and 10 years, respectively. In the 34 patients received postoperative irradiation of the mediastinum, survival was 16% higher. The survival rates after 5 years were similar for epidermoid carcinoma (18%) and adenocarcinoma (14%). The results of surgical treatment are variable and depend on several factors: extension and extrapulmonary location of lesions, surgical technique used for T-3 tumors and histological type.

Subtotal Liver Calcification Due to Epithelioid Hemangioendothelioma

A hepatic epithelioid hemangioendothelioma leading to almost complete calcification of the right and left liver lobes in a 75-year-old female is reported. Over a period of 16 years the liver progressively calcified, but its function remained normal by compensatory hypertrophy of the caudate lobe. Multiple partially calcified metastases were present in the lungs, peripancreatic region and along the left principal bronchus. Extreme liver calcification has only rarely been reported. The case presented here reflected slow tumor growth and subsequent long disease course. The vascular nature of the tumor was confirmed by immunohistochemical and ultrastructural analysis.

Localization of [D-Ala2]deltorphin I-like immunoreactivity in perinatal rat respiratory system

The localization of [D-Ala2]deltorphin I, a delta-opioid receptor ligand, was studied in the lower respiratory tract of developing rats using an immunohistochemical method. [D-Ala2]-like immunoreactive cells were detected first in the principal bronchus as early as embryonic day 16. As embryos grew, positive cells became gradually visible everywhere from principal bronchi to respiratory bronchioles. The density of positive cells reached the highest level on embryonic day 21, but decreased gradually after birth. Positive cells were no longer seen on postnatal day 30 in any region of the airways. No positive cells were ever found in the trachea or alveoli of rats at any age studied. Ultrastructural examination indicated that the immunoreactive cells possessed a similar morphology to serous or Clara cells of the respiratory epithelium. Immunoreaction products tended to locate at the apical cytoplasm of positive cells. The results suggests that [D-Ala2]-like molecule(s) may be expressed transiently in serous cells or Clara cells, or both, of the rat bronchopulmonary tract. Such a molecule may act as a pulmonary growth-promoting or a differentiation-initiating factor in an early period of lung development.

Endoscopic anatomy and map of the equine bronchial tree.

To develop a bronchoscopic map of the equine respiratory tree, the major airways of the lungs of 6 healthy Thoroughbred horses were systematically explored with a flexible fibreoptic endoscope through a tracheostomy while the horses were sedated in stocks. With the carina as the reference point, measurements were made of distances to the branches of the major airways using markers on the shaft of the endoscope. All branches were explored until the narrowing of their diameters prevented further advancement of the endoscope. Positions of origins of branches from the parent bronchus were recorded in relation to a 12 h clock. Branching patterns of the right and left lungs were similar. Seventeen branches of the principal and caudal lobar bronchi of the left lung, and 18 branches of the principal and caudal lobar bronchi of the right lung were identified. Mean explorable distances from the carina to the ends of the right and left caudal lobar bronchi were 34.0 +/- 3.5 (sd) and 34.5 +/- 3.0 cm, respectively. Generally, smaller horses had shorter explorable bronchial lengths. Branching patterns of the parent bronchi were fairly consistent among horses, particularly the branches closest to the carina. After endoscopy and euthanasia, the lungs were removed, and dried with pressurised air flowing through them for 7-10 days. Attempts to explore the airways of the dried lungs endoscopically were relatively unsuccessful, because airways were much smaller in the dried lungs, and many of the branches were distorted when compared with their antemortem appearances. However, having a dried lung specimen as a reference during the bronchoscopic procedure was useful for maintaining orientation in the lungs. Radiographs were used to estimate the location of the origin and destination of each airway branch in relation to the nearest intercostal space. This makes the airway map useful when lesions identified radiographically are to be lavaged.

Bronchial Branching Abnormalities and Emphysema‐like Changes in Mutant Rats Having Congenital Lobation Anomalies in the Lung

ABSTRACT The present study aimed at investigating in fpl/fpl mutant rats survived to adulthood 1) whether bronchial branching abnormalities were the primary defects of pulmonary lobation anomalies, and if this was the case, 2) whether these anomalies could lead to respiratory dysfunction. Examination of corrosion casts made from the malformed lungs of adult fpl/fpl rats revealed a variety of branching abnormalities in the right bronchial tree, such as ventral ramification of the middle lobar bronchus, abnormal curvature of the intermediate lobar bronchus, and positional abnormalities of the middle lobar bronchus and first segmental bronchus of the intermediate lobar bronchus, while reduction in the number of segmental bronchi was the only minor abnormality found in the left lung. These results conformed to our previous observations in which the main manifestation of the fpl mutation was restricted to the right lung lobes, and indicated that the primary defect of this malformation was bronchial branching abnormalities. In these rats, stenosis of the trachea, right and left principal bronchi, and some lobar and segmental bronchi also became evident by calipering their circumference. Histopathological examination of the lungs revealed abnormally expanded airspaces accompanied by destruction of alveolar walls and macrophage infiltration in aged fpl/fpl rats. These observations suggest that fpl/fpl rats suffer emphysema‐like respiratory dysfunction with advancing age from pulmonary lobation anomalies conforming to tracheal and bronchial malformations.

Nitric oxide synthase in guinea pig lower airway innervation

The inhibitory non-adrenergic non-cholinergic (i-NANC) innervation of the guinea pig airways was suggested to be mediated, at least partially, by nitric oxide (NO). The enzyme catalyzing the generation of NO and citrulline from l-arginine, nitric oxide synthase (NOS), was found to be identical with neuronal nicotinamide-adenine dinucleotide hydrogen phosphate (NADPH)-diaphorase. In the present study, we report the distribution of NOS in guinea pig lower airways and in vagal sensory and sympathetic ganglia as revealed by NOS immunohistochemistry and NADPH-diaphorase histochemistry. The distribution of NOS was identical using either technique and displayed a similar distribution pattern in all parts of the lower airways. Yet, the number of NOS-containing fibres was increasing from cervical trachea towards principal bronchi and decreasing to complete absence in bronchioli. Innervation with NOS-containing nerve fibres was densest in the smooth muscle layer and in the lamina propria of the mucosa. Single fibres were found in the respiratory epithelium. Labelling was absent from nerve fibres innervating the submucosal glands. Perivascular fibre networks enmeshed tracheal arteries, pulmonary arteries and veins. A substantial number of NOS-immunoreactive and NADPH-diaphorase-positive neurons was observed in vagal sensory ganglia, whereas such neurons were rather sparse in sympathetic ganglia. Tracheal and peribronchial ganglia of the airways were devoid of labelling. These findings suggest that extrinsic rather than intrinsic (tracheal and peribronchial) neurons are the source of NO release from guinea pig airway nerve fibres after electrical field stimulation. These extrinsic nerve fibres may originate from both sympathetic and vagal sensory ganglia.