We examined in vivo the effect of pilocarpine (a cholinergic agent) and cycloheximide (an inhibitor of protein synthesis) on the "bar-like structures" in alveolar type II cells of rat lung to clarify their origin and significance in pulmonary surfactant production and secretion. Lungs were examined with an electron microscope using ultrathin sectioning, freeze-fracture technique, and morphometry. The bar-like structures in type II cells consisted of a concentrically arranged endoplasmic reticulum containing some amount of osmiophilic periodic material similar to the lamellae of lamellar bodies. Pilocarpine induced the accumulation of lamellar bodies of normal size which paralleled the increase in the number of bar-like structures in the cytoplasm of the type II cells. Cycloheximide induced a decrease in size of the lamellar bodies and an enlargement of the bar-like structures. Our morphological findings suggest that: The phospholipid that would normally be incorporated into the lamellar bodies might be sequestered instead in the concentrically arranged endoplasmic reticulum, forming the bar-like structures, and The enlargement and the increased number of bar-like structures may be responsible in part for the changed metabolic process of surfactant production by alveolar type II cells.

Animals↗

PubMedDate not supplied

Inhalation of road dust by residents in polluted areas.

From March 1985 to March 1989, pneumomagnetic field strength (PMFS) was measured in 579 healthy subjects who lived in areas where there was substantial road dust pollution. In response to the government's campaign to eliminate the use of studded tires, suspended road dust produced by studded tires during the snowy season in the downtown areas of Sendai, Japan, decreased from 191 micrograms/m3 in March 1985 to 116 micrograms/m3 in March 1989. Suspended road dust in nonpolluted areas varied from 11 to 15 micrograms/m3. Road dust retained in the lungs, which contained 3% iron, was magnetized from the surface of the chest wall, and the PMFS was measured. The proportion of subjects with an abnormally high initial PMFS at the first measurement was 7 to 15% from 1985 to 1989; however, the PMFS of subjects who had an initially high PMFS decreased during each succeeding year. These findings suggest that, despite a government campaign to eliminate studded tires, road dust pollution is still being inhaled by the residents.

Air Pollutants↗

PubMedDate not supplied

Partial left ventriculectomy in patients with dialated failing ventricle.

BACKGROUND: While partial left ventriculectomy (PLV) improves left ventricular energetic efficiency, concomitant reduction in mitral regurgitation may improve ventricular function. METHODS: Two hundred ninety-five patients undergoing lateral ventricular wall excision between the papillary muscles (lateral PLV) and 101 patients with an additional excision of papillary muscles and mitral valve replacement (extended PLV) were compared with 65 patients undergoing excision of anterior wall or ventricular aneurysm (anterior PLV). RESULTS: All patients had reduced functional capacity, New York Heart Association (NYHA) Class III to IV (3.62+/-0.49). Etiologies were cardiomyopathy (37.3%), coronary artery disease (32.3%), valvular disease (19.7%), Chagas' disease (7.8%), and others (2.8%). Patients undergoing lateral and extended PLV had cardiomyopathy as the primary cause of heart failure, while a majority of anterior PLV patients had ischemic disease. Associated procedures included mitral valvuloplasty or replacement (lateral PLV 67%, extended PLV 100%, anterior PLV 40%) and tricuspid annuloplasty (67%, 76%, 28%, respectively.) In each group after surgery, end-systolic dimension decreased more than end-diastolic dimension despite reduced mitral regurgitation. Although extended PLV resulted in greater volume reduction and less mitral regurgitation, these patients had delayed recovery and poor survival. Patients with valvular disease had the most advanced myocardial hypertrophy with the best survival, while those with Chagas' disease had more severe myocarditis, interstitial fibrosis, and the poorest survival. CONCLUSION: Lateral PLV improved hemodynamics and functional capacity as much as aneurysmectomy by reducing ventricular volume and mitral regurgitation. Inclusion and exclusion criteria have to be sought to make PLV safer and more effective.

Cardiac Surgical Procedures↗

PubMedDate not supplied

Mitral regurgitation after partial left ventriculectomy as the cause of ventricular redilatation.

BACKGROUND: It remains unclear whether ventricular redilatation after partial left ventriculectomy (PLV) is due to underlying pathology or to continued volume overload amenable to surgery. METHODS: Among patients undergoing PLV, 32 had Doppler echocardiography preoperatively, immediately after surgery (< 1 week), early after surgery (1-3 months), and late after surgery (8-14 months). Patients were divided into groups with mitral regurgitation (MR; MR+, n = 16) and without postoperative MR (MR-, n = 16) and were compared for ventricular size, performance, and survival. RESULTS: After initial surgical reduction, left ventricular dimension on average gradually increased back to the preoperative level in subgroups of patients with valvular disease and cardiomyopathy and in all patients combined. Most patients showed drastically reduced left ventricular dimension early after PLV. In MR+ patients, dimension increased back to the preoperative level within 3 months after surgery, whereas the MR- group maintained reduced dimension throughout the first year in all patients combined and in a subgroup of patients with cardiomyopathy. Occurrence of significant MR after PLV appeared to be related to severity of fibrosis in excised myocardium but not to severity of preexisting MR, etiology, or performance of mitral valvuloplasty. CONCLUSIONS: Early postoperative MR, residual or new, appeared to play an important role in dictating early hemodynamics and late outcome in patients undergoing PLV. Results suggest an aggressive simultaneous approach to abolish MR. Causative role of myocardial fibrosis remains unclear and needs further study.

Adult↗

PubMedDate not supplied

Perioperative ventricular arrhythmias in patients undergoing partial left ventriculectomy.

BACKGROUND: Although incidence of ventricular arrhythmias after partial left ventriculectomy (PLV) has been reported, there are no studies comparing incidence before and after PLV. Although operative scars may give rise to arrhythmias, improved energetic efficiency after PLV may decrease their incidence. METHODS: Pre- and postoperative ventricular arrhythmias were monitored by Holter ECG and analyzed in 17 patients undergoing PLV in Curitiba, Brazil. RESULTS: Although total 24-hour heart beat (THB) increased significantly (p = 0.018), ventricular premature contractions (VPCs) decreased markedly (p = 0.036), excluding one patient dying in low cardiac output (LOS) who had terminal arrhythmias increased multifold. In the remaining 16 patients, VPC pairs were also reduced significantly on the average (p = 0.038). In contrast, ventricular tachycardia (VT; more than three consecutive VPCs) disappeared in five patients, decreased in two patients, and newly occurred in four patients, with five patients showing no change; one of them developed a prolonged VT, successfully reversed by external cardioversion. CONCLUSIONS: Despite notable significant increase in THB immediately after PLV, PVC and PVC pairs were significantly decreased in contrast to VT, which disappeared in some patients and newly occurred in other patients, remaining constant on the average. Sustained VT occurring in a patient with all other arrhythmias suppressed may suggest a unique electrophysiological substrate, may justify prophylactic use of amiodarone or an implantable cardioverter-defibrillator, and may underscore the importance of further and extended studies.

Adolescent↗

PubMedDate not supplied

Transventricular mitral annuloplasty in a patient undergoing partial left ventriculectomy.

A 70-year-old male patient with heart failure resulting from dilated cardiomyopathy underwent a partial left ventriculectomy between the papillary muscles and a newly devised transventricular mitral annuloplasty. Intraoperative transesophageal Doppler echocardiography revealed reduced ventricular dimensions and corrected mitral insufficiency with unchanged ventricular filling patterns, allowing prompt recovery despite unchanged myocardial pathology.

Aged↗

PubMedDate not supplied

Endoscopic bronchial polypectomy by high-frequency electric surgery.

Although polypectomy by high frequency electric surgery through the use of endoscopy has been widely applied to polypoid lesions in digestive canals, there have been very few reports of the treatment of bronchial lesions with this procedure. Recently, we have been successful in performing polypectomy without any complications using high-frequency electric surgery through a flexible bronchoscope in a patient with a benign bronchial polyp. Bronchial polypectomy by electric surgery has the advantages of preventing bleeding and providing large specimens for histological examination, compared with conventional methods, i.e. for forceps or laser methods.

Aged↗