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Biomedical subjects

A G Little

Publications and source records attributed to A G Little.

At least 19 recordsLinked to original sources
PubMed1998

Metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor.

Although metastatic carcinoma from an unknown primary tumor is known to occur, the combination of squamous cell carcinoma histologic findings and a mediastinal location is quite unusual. The evaluation of a case of a patient with a posterior mediastinal mass, eventually shown to be metastatic squamous cell carcinoma of the mediastinum with unknown primary tumor, is described herein. Resection of the lymph node mass was performed and was followed by chemoradiation for presumed lung cancer.

Carcinoma, Squamous Cell↗
PubMed1998

Pathogenesis and management of persistent postthoracotomy pain.

Persistent chest wall pain is common after thoracotomy and is usually caused by recurrence or progression of malignancy. It should prompt efforts to identify and treat the causative disease. A minority of patients experience persistent pain not related to neoplasm. This pain may last for years, but is usually not severe. A small subset of these patients experience persistent severe pain, which may be debilitating. The pain may be owing to various causes. Diagnosis and treatment should be individualized and directed toward the causes believed to be present. First-line pharmacologic therapies include NSAIDs, tricyclic antidepressants, antiepileptics, and low-dose opioids. Some patients require more sophisticated treatment from multidisciplinary pain-management clinics. This treatment may include nerve blocks, physical therapy, sympathectomy, cryoneurolysis, or long-term neuromodulation with epidural analgesia or spinal cord stimulation. Because of the severe pain these patients may experience and the difficulty and expense associated with treatment, prevention may be the best strategy for dealing with this problem. Recent laboratory and clinical studies indicate that minimizing perioperative pain can suppress certain alterations in the nervous system that may prevent the genesis and maintenance of chronically painful conditions. This suggests that strategies for avoiding PTPS may begin with aggressive perioperative anesthetic and analgesic techniques. More effective application of knowledge already available from laboratory studies awaits further clinical trials. New drugs such as NMDA inhibitors hold promise for more effective treatment in the future.

Algorithms↗
PubMed1996

Thoracoscopy: current status.

This article presents the current status of thoracoscopy in clinical practice. Aspects of its use in diagnostic, staging, and therapeutic areas are reviewed as regards diseases of the pleura, lung, and mediastinum. Controversies and evolving applications are identified.

Endoscopy↗
PubMed1995

Problem orientation is a new approach to surgical education.

BACKGROUND: There is increasing interest in educational methods that are loosely aggregated under the title of problem-based learning (PBL), but it remains unclear whether PBL is as successful as its conventional predecessor in transmitting factual information. MATERIALS AND METHODS: The authors designed and implemented a PBL curriculum for a third-year surgical clerkship, then prospectively compared that technique with the conventional format. Each student's subject-related knowledge was assessed with a specifically tailored 195-question written exam and correlated with National Board of Medical Examiners shelf exams. Student and faculty responses to the technique were also sought and tabulated. RESULTS: Student and faculty responses to PBL were uniformly positive. We were unable, however, to demonstrate effects on our evaluation instruments. Neither individual student performance nor grouped scores differed based on the mode of presentation. CONCLUSION: A PBL curriculum generates both student and faculty enthusiasm. Unfortunately, this does not translate into more efficient transmission of knowledge.

Clinical Clerkship↗
PubMed1995

Reduction pneumonoplasty for emphysema. Early results.

OBJECTIVE: The authors determined the role of Nd:YAG laser reduction pneumonoplasty for selected patients with diffuse emphysema. SUMMARY BACKGROUND DATA: The study is based on the concepts introduced 30 years ago by Brantigan regarding the value of lung reduction surgery in patients with emphysema. The authors used minimally invasive techniques with the hopes of providing appropriate clinical results with the least surgical morbidity. METHODS: Fifty-five patients with advanced symptomatic emphysema were treated with unilateral Nd:YAG laser reduction pneumonoplasty to achieve lung volume reduction. RESULTS: Patients experienced significant improvement in exercise capacity and relief of breathlessness. This correlated with improvement in objective measures of pulmonary function and with reduction in lung volume by radiographic and spirometric measures. Significant associated hospital morbidity and a 5.5% mortality were associated. CONCLUSIONS: These encouraging results with treatment of only one lung will be built on with both sequential lung and simultaneous, bilateral lung treatment protocols.

Humans↗
PubMed1994

Erythromycin strengthens the defective lower esophageal sphincter in patients with gastroesophageal reflux disease.

Motilin induces phase III activity of the gastrointestinal tract. Erythromycin has a motilin-like effect on the stomach and significantly increases the lower esophageal sphincter (LES) pressure in normal volunteers. This investigation was performed to evaluate the effects of erythromycin on esophageal function in patients with gastroesophageal reflux disease (GERD). Esophageal manometry was performed in 10 GERD patients before and after intravenous infusion of 500 mg of erythromycin. Values are expressed as mean +/- SEM. LES pressure increased from 13.9 +/- 2.9 mm Hg at baseline to 28.9 +/- 3.6 mm Hg after infusion of erythromycin (p < 0.01). The duration of contractions in the proximal, middle, and distal esophagus was significantly prolonged from 3.5 +/- 0.4 seconds, 3.8 +/- 0.4 seconds, and 4.1 +/- 0.5 seconds to 4.2 +/- 0.2 seconds, 4.6 +/- 0.5 seconds, and 5.6 +/- 0.6 seconds, respectively, after infusion of erythromycin (p < 0.05 for each comparison). Erythromycin did not effect esophageal body contraction amplitude or velocity, or the upper esophageal sphincter. Serum motilin decreased slightly after the administration of erythromycin. We concluded the following: (1) Erythromycin profoundly stimulates the defective LES in patients with GERD. This appears to be a direct motilin agonist-like effect rather than being mediated by release of endogenous motilin. (2) Erythromycin has less effect on the esophageal body, although it does prolong the duration of esophageal contractions.

Erythromycin↗
PubMed1994

Failed antireflux operations. Pathophysiology and treatment.

This article reviews the pathophysiology of failed antireflux operations and sets forth diagnostic and therapeutic strategies. Utilization of esophageal function tests is stressed. A thoracic rather than abdominal approach is recommended to provide all surgical options.

Gastroesophageal Reflux↗
PubMed1993

Calcium effects on human esophageal smooth and striated muscle.

Because of conflicting results in earlier investigations, our study was carried out to determine the effects of acute hypercalcemia on esophageal muscle function at the lower esophageal sphincter and on the smooth and striated muscle of the esophageal body. Variables measured included lower esophageal sphincter pressure and length and esophageal body contraction pressure, duration, and velocity in the middle, distal, and proximal esophagus. Despite 3 hr of induced acute hypercalcemia, there were no statistically significant changes in any of the variables. Although esophageal muscle contraction requires calcium, our results, in contrast to some earlier studies, suggest that the availability of excess calcium does not effect esophageal function.

Adult↗
PubMed1993

Erythromycin, motilin, and the esophagus.

BACKGROUND: Motilin induces phase III activity of the gastroesophageal tract. Erythromycin has a motilin-like effect on the stomach, but possible esophageal effects have not been evaluated and are the focus of our investigation. METHODS: Esophageal manometry was performed in 11 healthy volunteers before and after intravenous infusion of 500 mg erythromycin. Values are expressed as means +/- SEM. RESULTS: Lower esophageal sphincter (LES) pressure increased from 21.1 +/- 2.6 mm Hg at baseline to 37.5 +/- 3.8 mm Hg after erythromycin infusion (p < 0.0001). Erythromycin did not affect LES length, esophageal body contraction amplitude, duration or velocity, or the upper esophageal sphincter. Serum motilin levels decreased from 96.4 +/- 10.9 pmol/L to 81.8 +/- 10.9 pmol/L (p < 0.01) after erythromycin administration. CONCLUSIONS: Erythromycin profoundly stimulates the normal human LES. This is a direct motilin agonist-like effect and is not mediated by release of endogenous motilin. Erythromycin has no important effect on the esophageal body or the upper esophageal sphincter.

Adult↗
PubMed1992

Somatostatin stimulation of the normal esophagus.

The inhibitory effects of somatostatin on gastric and small bowel motor function are well documented. However, the effects of somatostatin on esophageal body motility and lower esophageal sphincter tone are not completely defined. We investigated the effects of octreotide, a long-acting somatostatin analogue, on the esophageal body and the lower esophageal sphincter in 15 healthy volunteers. Lower esophageal sphincter tone was increased by octreotide infusion. Esophageal body contraction amplitude and velocity were also increased by octreotide infusion. Our data show that somatostatin stimulates the normal human esophagus, an action mediated either by a direct effect, a central nervous system action, or the inhibition of the secretion of gastrointestinal hormones that influence esophageal motor activity.

Adult↗