Journal of the Association for Academic Minority Physicians : the official publication of the Association for Academic Minority Physicians最新文献

Current changes in the clinical diagnosis and management of acute appendicitis relate to managed care policies and procedures, newer diagnostic techniques, laparoscopy, scoring analysis of clinical data, and nonoperative treatment. Analysis of results of studies using ultrasonography, computed tomography, radionuclide scanning, and diagnostic scoring continues with the intent of developing improved sensitivity and specificity in predicting the presence of acute appendicitis, but it is still not possible to achieve an accurate, uniform, definitive preoperative diagnosis of the disease. The addition of current diagnostic procedures has probably shortened the period of observation for doubtful cases of acute appendiceal inflammation and has established the presence of the disease by means other than clinical examination, interpretation of symptoms, and laboratory tests. Diagnostic scoring systems have been described with enthusiasm, but they are not generally popular and require considerable effort to be clinically useful. The use of laparoscopy and laparoscopic appendectomy is exciting and very in tune with the modern trend in abdominal surgery. However, increasing concern has been expressed that diagnostic advances will be paralleled by delays in patient treatment. Since some delays have been described for management and treatment of acute appendicitis, any delays related to new trends in health care system organization should be monitored carefully.

Most patients with carcinoma of the esophagus present with progressive, unrelenting dysphagia, malnutrition, and weight loss. Palliation is the primary treatment, since these patients are not candidates for curative surgical resection. Surgery, radiotherapy, and endoscopic modalities have been used for palliation. Recently, self-expanding, metallic stents have been used with considerable success. This type of stent can dislodge into the stomach during or after deployment. We report an approach to retrieve an expandable, silicone-coated stent using a double-channel endoscope, an esophageal dilating balloon, and a polypectomy snare.

More than a dozen years ago, case rates of tuberculosis (TB) began to increase in the United States, as well as in other industrialized and Third World countries. Our US urban centers were the epicenter of the "new" TB epidemic, with New York City accounting for more than 15% of all TB cases in the United States. Numerous factors were responsible for this dramatic, unexpected explosion in mankind's most prevalent and lethal disease, including (1) an increasing pool of susceptible individuals who, by virtue of human immunodeficiency virus (HIV) infection, were much more likely to rapidly progress to active (contagious) TB after becoming infected with Mycobacterium tuberculosis; (2) a reduction in the resources and sites available for the identification, treatment, and surveillance of patients with tuberculous infection and disease; and (3) the importation of TB cases via immigration. Coupled with the resurgence of tuberculosis, new strains of difficult-to-treat, multiple-drug-resistant M tuberculosis (MDRTB) were isolated with increasing frequency, with New York City again the focal point. More than 60% of the nation's MDRTB cases occurred in New York City, reaching a peak of 441 cases in 1992. Over the past 2 years, epidemiologic data suggest that the epidemic has come under control, with a 38% decrease in new cases (1995) compared with the peak year (1992). A number of factors have been important in regaining control of TB, including enhanced diagnostic modalities, such as the use of some molecular biologic strategies; active case and contact finding by public health workers; tailored therapeutic approaches, such as four-drug initial therapy for non-MDRTB, advanced multidrug management for MDRTB, and expanded use of directly observed therapy; and use of personnel-protective devices and environmental controls to decrease nosocomial transmission of TB. These factors are highlighted in this overview article.

Academic health centers (AHCs) currently face the greatest challenge of their entire existence. Managed care, increased competition for research funding, and inefficiency all contribute to the present vulnerability of AHCs in the cost competitiveness of today's health care marketplace. The increased reliance of medical schools on clinical income to subsidize undergraduate and graduate education and biomedical research now jeopardizes the success of their missions, since clinical income is declining. While AHCs must make significant changes to adapt to the new environment, left on their own in the marketplace, many will not survive. Additionally, the biomedical research advances and high technology medical care that we have come to expect in this country will also likely suffer. A national approach designed to preserve responsive AHCs is needed.

Sucralfate inhibits activity of certain Helicobacter pylori enzymes, implying that this medication may limit gastric cell injury associated with H pylori infection. This study evaluates the ability of sucralfate and its two major structural components, sucrose octasulfate and aluminum hydroxide, to reduce the cytotoxic effects of H pylori and to inhibit binding of H pylori to human gastric epithelial cells. Experiments were performed using human gastric epithelial cells isolated from gastric biopsy tissue taken at upper gastrointestinal endoscopy. Primary cultures of human gastric epithelial cells, when exposed to broth-culture supernatant from a vacuolating cytotoxin-positive H pylori strain, were shown to form cytoplasmic vacuoles. Preexposing H pylori brothculture supernatant to sucralfate reduced vacuole formation in human gastric epithelial cells; however, preexposure of H pylori broth-culture supernatant to aluminum hydroxide or sucrose octasulfate did not reduce vacuolation in human gastric epithelial cells. H pylori binding to human gastric epithelial cells was significantly reduced when H pylori was exposed to sucralfate prior to incubating the bacterium with human gastric epithelial cells. These data show that sucralfate, but not its two major components, reduces the toxicity of an H pylori-produced cytotoxin (VacA) and decreases H pylori adherence to human gastric epithelial cells. This reduction in H pylori cytotoxicity may contribute to sucralfate's ulcerhealing properties and to the lower ulcer recurrence rates seen in patients treated with this medication.

Pulmonary infections, including mixed infections, are common in patients with human immunodeficiency virus (HIV), and a specific diagnosis is desirable to direct therapy. In a retrospective study of patients suspected of having Pneumocystis carinii pneumonia, we examined the usefulness of fiberoptic bronchoscopy in the immediate diagnosis of tuberculosis. In 267 patients, pneumocystis pneumonia was diagnosed in 115 (43%), of whom 5 (4%) also had concomitant tuberculosis. Bronchoalveolar lavage gave an immediate diagnosis of tuberculosis by positive acid-fast bacilli stain in 3 patients, while the transbronchial biopsy was suggestive in a fourth. Four of these patients developed respiratory failure, and 2 died. In patients with pneumocystis pneumonia, respiratory failure was significantly more common in those with tuberculosis (P = .0077). In 156 (58%) of the 267 cases, bronchoalveolar lavage was negative for pneumocystis pneumonia, while tuberculosis was diagnosed in 14 (9%), and an immediate diagnosis was made in 10 (71%). In a series of HIV-infected patients suspected mainly of having pneumocystis pneumonia, tuberculosis was found instead in 19 (7%), and both diseases were present in 5 (2%). Bronchoscopy provided an early diagnosis of tuberculosis in 63%. Patients with concomitant pneumocystis pneumonia and tuberculosis had a high rate of respiratory failure.

Since increasing evidence suggests that several proteins play a significant role in the regulation of glucose oxidation in the central nervous system, a series of experiments was designed to determine the specific proteins involved and to delineate their possible mode of action. In these studies, the rate of substrate oxidation by isolated synaptosomes in vitro was determined by measuring the production of [14C]carbon dioxide from labeled compounds in the presence and absence of the added protein. In the initial experiments, an examination of a broad selection of pure proteins revealed that only albumin (bovine serum albumin [BSA]) or histones (at concentrations of 100 micrograms/mL or less) exhibited an inhibitory effect of greater than 60% on the rate of glucose oxidation. Furthermore, isolated cell fractions P1 (nuclei and cellular debris), P2 (mitochondria, synaptosomes, and myelin), and other membrane proteins had little or no effect on the rate of [14C]carbon dioxide production from [6(14)C]glucose. When either BSA or histones were treated with trypsin, the inhibitory effects were eliminated. To determine whether these effects were related to changes in substrate transport, we measured the rate of glucose uptake by synaptosomes using [6(14)C]glucose, [1,2-3H]2-deoxyglucose, and [3H]3-O-methylglucose in the presence of 5% serum protein. These experiments revealed that the rate of glucose transport was not affected by serum proteins. Collectively, these results indicate that albumin and histones attenuate the rate of glucose oxidation by synaptosomes. The results also support the conclusion that the intact protein molecule is required for this inhibition, since treatment with trypsin abolished this effect. It can also be concluded that this effect is not at the site of transport and that the protein(s) are acting either directly at intercellular site(s) or indirectly via specific messengers.

Internal pancreatic fistulas are rare but debilitating complications of chronic pancreatitis. Fistulous tracts from the pancreatic duct to the peritoneal or pleural cavities have been treated by medical therapy and surgical management, with success rates of 41% and 89%, respectively. Endoscopic stent placement for internal and external pancreatic fistulas has also been shown effective. We report on three patients with histories of chronic alcohol abuse and pancreatitis. Two patients presented with dyspnea and pleuritic chest pain. Imaging studies revealed pleural effusions, and endoscopic retrograde cholangiopancreatography (ERCP) demonstrated a patent fistulous tract from the pancreatic duct to the pleural cavity in each patient. Chemical analysis of the pleural fluid indicated pancreatic origin. The third patient, who had left-upper-quadrant abdominal pain and a small pleural effusion, had a large noncommunicating pseudocyst adjacent to the stomach. Nasopancreatic drains, along with chest tube drainage, were placed in the patients with pancreatic pleural fistulas. The patient with the pseudocyst received nasocystic drainage via the stomach. Drainage was measured until closure of the fistulas or cyst. Additionally, simply by injecting contrast medium, we were able to monitor the closure of fistulas without ERCP. The fistulas closed within 7 days, and the pseudocyst resolved within 14 days. Following discharge, all three patients were pain free, without evidence of recurrent fistulas or pseudocyst. In conclusion, the use of nasopancreatic/cyst drainage is an effective and convenient way to treat internal, communicating collections and pseudocysts of pancreatic origin. Furthermore, this method provides a simple means of assessing closure of fistulas and pseudocysts.