Radionuclide esophageal transit study in detection of esophageal motor dysfunction: comparison with motility studies (manometry)

Radionuclide esophageal transit study (RETS) has been developed to assess motor function of the esophagus. The purpose of this study was to compare RETS to esophageal motility studies (EMS) in detection of motility disorders. A total of 109 consecutive patients without previous history of surgery on the esophagus underwent both RETS and EMS within one month of each other. Final diagnosis was divided into three categories: I--primary esophageal motor disorders (n = 39); II--reflux disease (n = 48); and III--non-cardiac chest pain and/or dysphagia (n = 22). Using EMS as the standard, the results of RETS were as follows: sensitivity for detection of motor dysfunction was 97%, 92%, and 77% for Groups I, II, and III, respectively, while specificity was 91% for Group II and 100% for Group III. Global sensitivity was 92% and specificity was 88%. No clinically significant motor disorders were missed by RETS. In conclusion, RETS is a useful noninvasive test for the screening of patients with symptoms thought to be of esophageal origin.

Anatomic landmarks to estimate the length of the diaphragm from chest radiographs: effects of emphysema and lung volume reduction surgery.

STUDY OBJECTIVES: To define anatomic landmarks that can be used to predict insertions of the diaphragm on chest radiographs and to estimate diaphragm length. DESIGN: Prospective clinical trial with a parallel group design. SETTING: Laboratory investigations in normal volunteers recruited by advertisement and in emphysema outpatients being evaluated for elective bilateral lung volume reduction surgery (LVRS). PATIENTS: Twenty-six normal subjects classified into young and older age groups, with a third group of 13 emphysema patients matched for age and sex with the older group. MEASUREMENTS: Identification and between-group comparisons were made of anatomic landmarks on anteroposterior and lateral chest radiographs obtained at total lung capacity. Predicted landmarks were generated from normal subjects. Within-subject and between-group comparisons were made of diaphragm length index (DLI) based on observed anatomic landmarks (DLIobs) and diaphragm length index based on predicted anatomic landmarks (DLIpred) at functional residual capacity. RESULTS: Anatomic landmarks were not different between the three groups or between male and female subjects, and were not different before and after LVRS in emphysema patients. No difference was found between DLIobs and DLIpred in normal subjects and emphysema patients, but both were smaller in emphysema patients than in normal subjects and increased after LVRS in emphysema patients. CONCLUSION: This study validates the use of anatomic landmarks to estimate DLI. Using these landmarks simplifies the determination of diaphragmatic lengths and could be a useful tool for the evaluation of the functional capacity of the diaphragm, and possibly as a prognostic indicator of patients who are candidates for LVRS.

Replacement of the superior vena cava with polytetrafluoroethylene grafts combined with resection of mediastinal-pulmonary malignant tumors. Report of thirteen cases.

From 1979 to 1986, we replaced the superior vena cava with polytetrafluoroethylene grafts in 13 patients to enable resection of malignant mediastinal or pulmonary tumors. Five prostheses could be interposed between a tumor-free proximal superior vena cava and right atrium while eight required separate innominate anastomoses (Y grafts constructed intraoperatively). There were no deaths. Phlebograms obtained 15 to 30 days after the operation demonstrated patency in 12 of 13 patients. Long-term (average 24 months) patency was evident in eight. Five patients are alive at 1, 3, 40, 49, and 60 months, a cumulative survival rate of 27% at 3 years.

Relationship of a hiatal hernia to the function of the body of the esophagus and the gastroesophageal junction.

One hundred two patients referred to our Esophageal Function Laboratory without endoscopic evidence of esophagitis were divided into two groups on the basis of the presence of a hiatal hernia on endoscopic examination. Fifty-three patients had a hiatal hernia and 49 did not. Both groups and 30 normal volunteer subjects had esophageal manometry and 24 hour esophageal pH monitoring. The incompetency of the cardia in patients with a hiatal hernia was dependent upon loss of components responsible for the antireflux mechanism, mainly a decrease in distal esophageal sphincter pressure and a decrease in the length of the sphincter exposed to the positive-pressure environment of the abdomen. These deficiencies were not related to the presence of a hiatal hernia and were similar to those of patients with an incompetent cardia without a hiatal hernia. Patients with a hiatal hernia and an incompetent cardia had significantly more esophageal exposure to refluxed acid than without a hiatal hernia. On the basis of the number of reflux episodes that lasted 5 minutes or longer and radioisotope transit studies, this increased acid exposure was due to both a loss of competency of the cardia and poor esophageal clearance secondary to the presence of a hiatal hernia. Reduction of the hernia and anchoring the distal esophagus into the abdomen not only may improve the antireflux mechanism, but corrects the clearance abnormality as well. The presence of a hiatal hernia has a detrimental effect on the clearance function of the body of the esophagus and may aggravate the effects of gastroesophageal reflux due to an incompetent cardia.

The role of the esophageal body in the antireflux mechanism.

The competency of the cardia depends on the interaction of the distal esophageal sphincter (DES) pressure and the length of the DES exposed to the positive-pressure environment of the abdomen. These two components were measured in 20 normal control volunteers and 126 patients with objectively proved gastroesophageal reflux. The results, when plotted on a grid with the horizontal bar representing the length of the abdominal esophagus and the vertical bar representing the DES pressure, indicated that factors in addition to the mechanical components of the cardia were important in the antireflux mechanism. The 24-hour esophageal pH records from the patients and the antireflux mechanism. The 24-hour esophageal pH records from the patients and normal subjects were analyzed as to the number of reflux episodes that occurred per hour while the patients were in the supine position and the ability to clear the refluxed acid by the propulsive "P"pump" of the body of the esophagus. It was concluded that the antireflux mechanism of the esophagus consists of a valvular cardia and a propulsive "pump" action of the body of the esophagus. The failure of either may lead to abnormal acid exposure but can be compensated by one or the other in normal subjects. Failure of both invariably leads to abnormal acid exposure. The cardia can fail either mechanically (i.e., having inadequate valvular components) or functionally (i.e., having normal valvular component but abnormal number of reflux episodes per hour). The latter suggests gastric pathology. Precise diagnosis of the reason for abnormal acid exposure is needed to develop a rational basis for therapy.

Effects of total fundoplication on function of the esophagus after myotomy for achalasia.

Twelve patients underwent distal esophageal myotomy for achalasia. After denuding the esophageal mucosa over 50 percent of its circumference, a short (2 cm) total fundoplication was performed over a size 56 mercury bougie. Clinical evaluation showed marked symptomatic improvement. Obstructive symptoms are minimal, and no reflux symptoms were noted. Manometric documentation showed a significant decrease in resting esophageal and lower esophageal sphincter pressure. Contraction pressure was also lowered, and peristalsis returned in 36 percent of the waves in the proximal esophagus. Radiologic and scanning documentation revealed slow emptying without evidence of significant reflux. Endoscopic evaluation revealed no esophagitis after 19 months' follow-up.

Effect of paraesophageal hernia on sphincter function and its implication on surgical therapy.

Fifteen patients with a paraesophageal hernia were studied with 24 hour esophageal pH monitoring and esophageal manometry to clarify the physiologic aspects of the cardia and resolve controversies over the type of surgical repair. The results were compared with those obtained in 34 randomly selected patients with a sliding hernia and 18 normal control subjects. Sixty percent of the patients with a paraesophageal hernia had an incompetent cardia on 24 hour pH studies which was associated with a lower esophageal sphincter of normal pressure, short overall length, and a small segment exposed to abdominal pressure. In comparison, 70 percent of patients with a sliding hernia had an incompetent cardia which was associated with a lower esophageal sphincter of low pressure, normal overall length, and a short segment exposed to abdominal pressure. With either type of hernia, symptoms were not helpful in determining the competency of the cardia. When urgent surgery is necessary, repair should include an antireflux procedure. If facilities and time permit, more specific evaluation of the cardia can be performed, and if competent, the repair should be limited to reduction of the stomach and closure of the defect.

Nuclear medicine and esophageal surgery.

The principal radionuclide procedures involved in the evaluation of esophageal disorders that are amenable to surgery are illustrated and briefly described. The role of the radionuclide esophagogram (RE) in the diagnosis and management of achalasia, oculopharyngeal muscular dystrophy and its complications, tracheoesophageal fistulae, pharyngeal and esophageal diverticulae, gastric transposition, and fundoplication is discussed. Detection of columnar-lined esophagus by Tc-99m pertechnetate imaging and of esophageal carcinoma by Ga-67 citrate and Tc-99m glucoheptonate studies also is presented.

The Concorde and cosmic rays.

In 1976, Air France's Concordes operated 2,642 h of flight time during 772 commercial flights to Rio de Janeiro, Caracas, and Washington. The cosmic radiation dose equivalent rate was measured during each of these flights. The average amount recorded was 0.99 mrems/h. A distinction must be made between the high latitudes (Washington route), on which an average dose equivalent rate of 1.49 mrem/h was recorded, and low latitudes (Rio de Janeiro and Caracas routes), on which the average dose equivalent rate was only 0.78 mrems/h. These figures show that 1976 Concorde passengers and crews were exposed to very low quantities of radiation--very much lower than the maximum value recommended for the general public, which is 500 mrems per year.

Vestibular habituation in flightcrew.

Vestibular habituation is a general reaction to any repetitive sensory stimulation. It can be characterized by four main features: acquisition, retention, loss or dishabituation, and transfer. This study concerns three groups of subjects: The first group consists of a) 27 pilots at present serving in the French Air Force, b) 12 pilots at present serving in the major civil airlines, c) 8 navigators, radio-navigators, and crew mechanics, some of whom are flying club pilots, and d) 3 professional pilots trained in flying clubs. All of these subjects had more than 2000 h flying time. They were from 27 to 50 years old. The second group consists of airline stewards. The third group consists of trainee pilots still in flying school. All of these subjects were examined for their suitability, in particular undergoing a damped swing test. The first oscillation was in an anticlockwise direction and the damping extended over 20 periods. The following parametre was measured: the ratio of total left nystagmus frequency to total right nystagmus frequency. In "normal" control subjects the ratio is greater than 1. The results were: The first group: In 41 out of 50 subjects, the ratio of left tremors frequency to right tremors frequency was less than or approximately equal to 1. In the second group: The results showed no significant differences in comparison with a control group of subjects. In the third group: Zero flying time--the results were identical with those of control subjects; 40 h flying time--the ratio approached 1; 100 h flying time--the ratio was less than 1. Vestibular habituation, that is inversion of the preponderance of the total number of left tremors over the total number of right tremors, was observed in the technical flightcrew. The appearance of this inversion during the pilots' training was studied and its retention tested. This test for showing vestibular habituation may be of use for monitoring the function of equilibrium and the development of habituation during flight training. In this report, we shall first review the definition and characteristics of vestibular habituation, and the main body of recent work on this phenomenon in flightcrew. Our own findings will be then presented.

[Surgical treatment of pneumothorax in AIDS patients]. / Traitement chirurgical du pneumothorax chez le patient sidéen.

A retrospective review of the charts of 26 patients with the acquired immunodeficiency syndrome (AIDS) treated at the Hotel-Dieu de Montréal was performed. Patients presented a total of 37 pneumothoraces. Eleven cases were recurrent. Bilateral pneumothoraces were documented in three patients, most of them (17) were severe (> 75%). Pneumocystis carinii pneumonia was the most frequently associated pathology. The initial treatment consisted in chest tube drainage. A definitive treatment was indicated in 7 patients with prolonged air leaks (> 10 days) or without lung expansion. Two median sternotomies with bilateral pleurectomies, bullae plication, and talcage were done, and 5 unilateral thoracotomies with pleurectomies and bullae plications were completed. The post-operative survival was variable and related to diseases associated with the syndrome. AIDS related pneumothoraces is a morbid condition which should be treated on an individual basis.

[Radiological changes of talc pleurodesis in cases of effusion]. / Modifications radiologiques du talcage pleural dans les cas d'épanchements.

This study is based on the observations of 86 pleurodesis done by talc insufflation during thoracoscopy in 82 patients suffering from benign (8%) and malignant (92%) pleural effusions. Serial chest films were obtained on every patient. Chest computed tomography was obtained in ten patients. The most frequent finding seen in the early phase and one month later was the appearance of loculations (94%) in selective areas of the thorax. Occasionally they take the appearance of airfluid levels (22%). These loculations are characteristically located in the axillary (60%), intrafissural (30%) and paramediastinal (34%) areas of the chest. In the late phase with a mean evolution time of 6 months, these loculations evolve in 77% of patients in areas of pleural thickening. CT of the chest demonstrates the presence of characteristic pleural thickening in the form of coarse (5/12) and/or fine linear densities (7/12) corresponding to talc deposits, on the pleural surface. These modifications are shown by light microscopy examination of the pleural done at the autopsy.

[Palliative treatment with an endoluminal prosthesis for obstruction of the esophagus and the cardia]. / Palliation par prothèse endoluminale de l'obstruction oesophagienne et du cardia.

Between December 1984 and September 1991, a total of 68 palliative esophageal intubations were performed in 57 patients. The mean age was 64 years, there were 40 males and 17 females. The more frequent causes of esophageal obstruction were malignant tumors of the esophagus (49%), lung (23%) and cardia (19%). Total dysphagia (24.5%), dysphagia to liquids (47%) and esophagotracheal aspiration (14%) were present in these patients. In 65% of patients insertion of the prosthesis was the first attempt at palliation, in the remaining patients it followed the failure of another type of palliation. The decision to palliate esophageal obstruction was established preoperatively in 86% of patients, in the remaining 14% it was decided at the time of surgery. The intubation by pulsion (Atkinson) [1] was successful in 57% of patients and by traction (Celestin) [2] in 86% of patients. The associated morbidity was 36% for the Atkinson prosthesis and 13% for the Celestin prosthesis, although the latter required a laparotomy. The in hospital mortality was 12.5%. The mean survival was 85 days. A normal or semi-solid diet was tolerated by over 60% of patients following intubation. Palliation of esophageal obstruction by intubation improves the quality of life but is associated with a high morbidity.

Effects of iron and temperature on expression of the Pseudomonas aeruginosa tolQRA genes: role of the ferric uptake regulator.

The tolQRA genes have been recently identified in Pseudomonas aeruginosa PAO. In this study, we examined the effect of iron and temperature on tolQRA expression. A promoterless lacZ gene was introduced downstream of plasmid-encoded tolQ and tolA, and expression was monitored by measuring beta-galactosidase activity of cultures. Addition of 25 microM FeCl3 to the culture medium reduced tolQRA expression by 50 to 60% in PAO but by only 25% in the fur mutant PAO A4. Northern hybridization analysis revealed that iron regulation occurs at the level of transcription and involves the P. aeruginosa ferric uptake regulator (Fur). Primer extension analysis was used to identify the proposed transcriptional start site of tolA. Although a putative Fur box was identified 20 bp upstream of the proposed start site, purified Fur did not bind to the tolA or tolQR promoter regions in an in vitro gel retardation assay. Therefore, iron regulation of the tol genes appears to involve an intermediate regulatory gene. Expression of tolQR and tolA was optimal at 37 degrees C and was reduced by 40 to 50% when cultures were grown at either 42 or 25 degreesC. Growth in high-iron medium at 25 degrees C further reduced tolQR and tolA expression.

Identification and characterization of the tolQRA genes of Pseudomonas aeruginosa.

The tolQ, tolR, and tolA genes from Pseudomonas aeruginosa PAO were cloned using degenerate oligonucleotide PCR primers designed based on conserved transmembrane regions of Escherichia coli TolQ and TolR and E. coli and Pseudomonas putida ExbB and ExbD. The resulting PCR product was used as a probe to isolate a 6.5-kb DNA fragment containing P. aeruginosa tolQ, tolR, and tolA. The nucleotide sequence of a 2.9-kb DNA fragment containing the tolQ, tolR, and tolA genes was determined. The DNA sequence predicts TolQ to be a 25,250-Da protein exhibiting 53% identity to E. coli TolQ. TolR is predicted to be a 15,788-Da protein, sharing 38% identity with the E. coli TolR protein. The P. aeruginosa tolA sequence predicts a 37,813-Da protein with 27% identity to the E. coli TolA. The P. aeruginosa TolQRA proteins were expressed in E. coli minicells. Analysis of plasmid-encoded tolQ::lacZ and tolA::lacZ promoter fusions in E. coli indicated that these genes are expressed at different levels, suggesting transcription from different promoters. Transcriptional analysis of the tol genes in P. aeruginosa revealed that the tolQ and tolR genes are cotranscribed as an approximately 1.5-kb transcript and that tolA is transcribed from its own promoter as an approximately 1.2-kb transcript. The P. aeruginosa Tol proteins were functionally unable to complement E. coli tol mutants, although P. aeruginosa TolQ was able to complement the iron-limited growth of an E. coli exbB mutant. Introduction of the tolQRA genes in the tol-like mutant PAO 1652 restored pyocin AR41 killing, indicating that the Tol proteins are involved in the uptake of pyocin AR41 in P. aeruginosa. Attempts to inactivate the chromosomal copy of the tolA or tolQ gene in the parent strain PAO proved to be unsuccessful, and we propose that inactivation of these genes in P. aeruginosa results in a lethal phenotype.

Expression of the Moraxella catarrhalis UspA1 protein undergoes phase variation and is regulated at the transcriptional level.

The UspA1 protein of Moraxella catarrhalis has been shown to function as an adhesin that mediates adherence to human epithelial cell lines in vitro (E. R. Lafontaine, L. D. Cope, C. Aebi, J. L. Latimer, G. H. McCracken, Jr., and E. J. Hansen, J. Bacteriol. 182:1364-1373, 2000). In the present study, cell lysates prepared from individual colonies of several M. catarrhalis wild-type strains were analyzed by Western blot analysis using monoclonal antibodies (MAbs) specific for the UspA1 protein. Expression of UspA1 was shown to exhibit phase variation that was correlated with both adherence ability in vitro and the number of guanine (G) residues contained within a homopolymeric [poly(G)]tract located upstream of the uspA1 open reading frame (ORF). Nucleotide sequence analysis revealed that isolates expressing relatively high levels of UspA1 had 10 G residues in their uspA1 poly(G)tracts, whereas isolates that expressed much lower levels of UspA1 had 9 G residues. This poly(G) tract was located 30 nucleotides (nt) upstream of the uspA1 ORF and 168 nt downstream of the uspA1 transcriptional start site. Primer extension experiments, RNA slot blot analysis, and cat reporter constructs were used to demonstrate that M. catarrhalis isolates with 10 G residues in their uspA1 poly(G) tracts expressed two-to threefold more uspA1 mRNA than did isolates which had 9 G residues in their poly(G)tracts. Northern hybridization analysis revealed that an intact uspA1 mRNA was readily detectable in RNA from M. catarrhalis isolates that had 10 G residues in their uspA1 poly(G) tracts, whereas no full-length uspA1 mRNA was observed in isolates whose poly(G)tracts contained 9 G residues. M. catarrhalis strain O35E uspA1 genes that contained wild-type and mutated poly(G) tracts were expressed in Haemophilus influenzae to demonstrate that the length and composition of the poly(G)tract affected expression of UspA1.

Influence of abdomen on respiratory mechanics in supine rabbits.

Previous studies showed that abdominal evisceration has no effect on respiratory system compliance. We hypothesized that this could be related to lung distortion in eviscerated animals. Methods were developed for continuous recording of pleural pressure (Ppl) at various sites over the costal (co) and diaphragmatic lung surface (di) in acutely and chronically instrumented rabbits. We compared deltaPpl,co and deltaPpl,di recorded at mid-lung height during inflations in anesthetized, paralyzed supine rabbits before and after evisceration. Cranial and caudal deltaPpl.co were the same under all conditions. In intact animals, deltaPpl.co and deltaPpl,di were equal at all inflation volumes, whilst in eviscerated animals, deltaPpl,di were smaller than deltaPpl,co, the difference increasing with lung inflation. At any given volume, rib cage circumference (Crc) was smaller after evisceration, but the Crc deltaPpl,co relationship remained unchanged. These results are indicative of non-uniform lung expansion after evisceration and are consistent with model predictions based on cylindrical deformation and lung stress-strain relationship. This deformation should mimic the effect of a reduced lung compliance, keeping respiratory system compliance of eviscerated animals nearly normal. Similar deformation should have occurred also in intact rabbits during strong inspiratory efforts and in the erect posture, because lower Ppl,di than Ppl,co values were observed at the same lung height under these conditions.

RegA, iron, and growth phase regulate expression of the Pseudomonas aeruginosa tol-oprL gene cluster.

The tol-oprL region in Pseudomonas aeruginosa appears to be involved in pyocin uptake and required for cell viability. The complete nucleotide sequences of the tolQRA and oprL genes as well as the incomplete sequences of tolB and orf2 have been previously reported. In addition, the sequence of a P. aeruginosa iron-regulated gene (pig6) has been described and found to share homology with an open reading frame located upstream of the Escherichia coli tolQRA genes (U. A. Ochsner and M. L. Vasil, Proc. Natl. Acad. Sci. USA 93:4409-4414, 1996). In this study, we cloned the remainder of the P. aeruginosa tol-oprL gene cluster and determined its nucleotide sequence. This cluster was found to consist of seven genes in the order orf1 tolQ tolR tolA tolB oprL orf2. Transcriptional analysis of this gene cluster was performed by detecting the presence of mRNAs spanning adjacent genes as well as by using a promoterless lacZ reporter gene fused to each of the seven genes contained in the tol-oprL locus. The results show that there are three major transcriptional units or operons in this region, orf1-tolQRA, tolB, and oprL-orf2, in contrast to the E. coli tol-pal region, where there are only two operons, orf1-tolQRA and tolB-pal-orf2. Analysis of gene expression indicated that the tol-oprL genes of P. aeruginosa are both iron and growth phase modulated. The first operon, orf1-tolQRA, is iron regulated throughout growth, but iron-regulated expression of tolB and oprL fusions occurs only in late log phase. The expression of the three operons was significantly less repressed by iron in fur mutants than in the wild-type strain, suggesting the involvement of Fur in the iron regulation of all three operons. RegA is a positive yet nonessential regulator of tol-oprL expression.