A pilot study to investigate the effect of plate size on meal energy intake in normal weight and overweight/obese women.

BACKGROUND: Smaller plates are often recommended as a strategy for controlling energy intake; however, the effect of plate size on meal energy intake in normal weight compared to overweight or obese individuals is not known. The present study aimed to investigate this further. METHODS: Ten normal weight [mean (SD) body mass index, 21.7 (2.0) kg m(-2) ] and 10 overweight or obese [31.7 (3.6) kg m(-2) ] women attended a metabolic laboratory on two separate days for lunch. In this cross-over study, subjects were randomly assigned to eat lunch using either a small (21.6 cm) or a large (27.4 cm) plate. Each subject self-served spaghetti mixed with tomato sauce from an individual serving bowl onto the assigned plate, and ate until satisfied. The meal was consumed alone at a private table. During the second study day, each subject underwent the same procedure but used the alternate size plate. The amount eaten and energy consumed were calculated and a mixed effects analysis of variance model was used to compare energy intakes. RESULTS: Energy intakes using the small and large plate were 1356 (515) and 1365 (393) kJ, respectively, in normal weight subjects and 1314 (632) and 1226 (431) kJ, respectively, in overweight/obese subjects. Neither plate size, nor plate size by weight status significantly affected meal energy intake. There was no plate size by weight status effect on ratings of palatability, hunger, satiety, fullness or prospective consumption. CONCLUSIONS: Plate size did not affect energy intake from a single meal in either the normal weight or overweight/obese subjects.

Pneumonic and nonpneumonic forms of legionellosis. The result of a common-source exposure to Legionella pneumophila.

Two male maintenance workers contracted legionellosis while cleaning the interior of a cooling tower contaminated with Legionella pneumophila. In one man severe, life-threatening Legionnaires' disease developed, whereas the other experienced a comparatively mild, self-limiting illness that was consistent with previous descriptions of cases of Pontiac fever. This report represents the first documentation of the development of both of these syndromes following exposure to a common source of the organism. The implications of this observation for the pathogenetic mechanisms that underly the different clinical manifestations of legionellosis are discussed.

Neuropathologic evaluation of 40 confirmed cases of Legionella pneumonia.

Autopsy examination of the brain was performed in 40 cases of Legionella pneumonia. Thirty-nine of 40 patients had underlying chronic or acute medical problems. Sixteen patients (40%) had neurologic signs or symptoms that were not explained by preexisting disease. CSF was normal in six of seven patients examined; CSF protein content was 66 mg/100 ml in one patient. Neuropathologic examination in all 40 patients demonstrated no lesions attributable to disseminated Legionella pneumophila. Mechanisms other than direct cerebral invasion by the causative organism must be sought to explain the neurologic manifestations of Legionella pneumonia.

Campylobacteriosis in man: pathogenic mechanisms and review of 91 bloodstream infections.

Five patients with Campylobacter fetus(previously called "Vibrio fetus") bacteremia are presented with enteric symptoms in four patients, a self-limited course in three, and with possible nosocomial infection in one patient who had disseminated malignancy. The clinical syndromes of 91 bacteremic patients with campylobacteriosis and C. fetus taxonomy and pathogenicity are reviewed. Studies of potential pathogenic mechanisms in enteric infections failed to reveal the production of either heat-stable or heat-labile, cholera-like enterotoxin, cytotoxicity or invasiveness. In comparison with different species of vibrio infections, C. fetus appears to produce disease by a different mechanism, one which involves a bloodstream infection, perhaps following penetration through the intestinal mucosa as has been demonstrated experimentally with salmonellae and yersinia. Such a pattern is consistent with the clinical pattern of C. fetus infections and the experimental studies reported herein.

Rapid diagnosis of Legionnaires' disease by urinary antigen detection. Comparison of ELISA and radioimmunoassay.

An enzyme-linked immunosorbent assay was developed to detect urinary antigen excreted by patients with Legionnaires' disease. Of 47 patients tested, antigen was detected in 39. Of these 39 specimens, 35 gave clearly positive results by visual analysis; four others required spectrophotometric verification of positive results. Antigen was not detected in any of 178 urine specimens from patients with other pulmonary, bacteremic or urinary tract infections after a quick and simple confirmatory test. The assay required more time to perform than a previously described radioimmunoassay but was of equivalent sensitivity and specificity and did not require expensive equipment or contract with radioactive reagents. We conclude that enzyme-linked immunosorbent assay is a rapid, sensitive and specific means for rapidly diagnosing legionnaires' disease that can be performed in clinical laboratories unwilling or unable to use radioisotopes.

The pathology of the Legionella pneumonias. A review of 74 cases and the literature.

Following the discovery of Legionella pneumophila as the cause of an epidemic of pneumonia at an American Legion convention in Philadelphia, a group of related bacteria were recognized as additional human pathogens. This newly established bacterial genus, Legionella, includes the agents of Legionnaires' disease, Pittsburgh pneumonia, and several related infections. There are many similarities in the pathology of human infection caused by all the Legionella species. All produce a severe confluent lobular or lobar pneumonia, and abscess formation is not uncommon. A leukocytoclastic inflammatory infiltrate of neutrophils and macrophages, "septic" vasculitis of small blood vessels, coagulation necrosis, and focal septal disruption are characteristic but not diagnostic features. The inflammatory response is clearly that of a bacterial pneumonia with a necrotizing component, and does not resemble most mycoplasmal, chlamydial, or viral pneumonias. The bacteria can be demonstrated well by special stains. Acid fastness of Legionella micdadei, the cause of Pittsburgh pneumonia, is a helpful presumptive clue to diagnosis. The bacteria can be presumptively speciated in tissue by direct immunofluorescence. In addition, reliable recovery of the organisms on agar media now allows a specific diagnosis to be made. As a group, these infections are properly referred to as the Legionella pneumonias.

Bilateral carotid body resection for the relief of dyspnea in severe chronic obstructive pulmonary disease. Physiologic and clinical observations in three patients.

For many patients with advanced chronic airflow limitation (COPD) the treatment of dyspnea remains inadequate despite medications, rehabilitation programs, and supplemental oxygen. Bilateral carotid body resection (BCBR) is a controversial operation which has been reported anecdotally to relieve dyspnea in such patients, but its risks and long-term effects are not known. We studied pulmonary function and the ventilatory response to exercise of three severely dyspneic COPD patients who had chosen independently and without our knowledge to undergo this operation. All three patients reported improvement in dyspnea following BCBR despite the absence of improvement in their severe airflow limitation (mean FEV1 = 0.71 L before and 0.67 L after BCBR). The three patients died 6, 18 and 36 months after the removal of their carotid bodies, still convinced of the efficacy of their surgery. Their reported relief of dyspnea was associated with substantial decreases in minute ventilation and deterioration in arterial blood gases. Arterial blood gases worsened both at rest (PO2 fell from 57 to 45 mm Hg; PCO2 rose from 45 to 57 mm Hg) and during identical steady state exercise (at peak exercise, PO2 fell from 46 to 37 mm Hg and PCO2 rose from 50 to 61 mm Hg) postoperatively. Total minute ventilation decreased postoperatively both at rest (-3.4 L/min, -25 percent) and with exercise (-9.4 L/min, -39 percent) primarily because of decreases in respiratory rate (from 21 to 16 breaths/min at rest and from 25 to 18 breaths/min with exercise), and this was associated with decreases in both oxygen uptake (-26 percent) and carbon dioxide production (-22 percent) for the same external exercise workload. Whether the reported improvement in dyspnea was due to decrease in ventilation resulting from decrease in respiratory drive, a surgical placebo effect or some other unestablished effect of removal of the carotid bodies deserves further study.

Comparison of media for recovery of clinical isolates of Legionella pneumophila.

Seven media were prepared in house or purchased commercially and were compared for their ability to recover Legionella pneumophila from clinical specimens. Media containing alpha-ketoglutarate from either source detected colonies earlier, more often, and in greater quantities than media without alpha-ketoglutarate. Media without charcoal performed poorly.

Use of rhesus monkey kidney cells for isolation of varicella-zoster virus.

The authors examined the performance of rhesus monkey kidney cells and human diploid fibroblasts (MRC-5 cells) in primary isolation of varicella-zoster virus from clinical specimens in a diagnostic virology laboratory. Seventy-two varicella-zoster virus isolates were recovered between 1985 and 1993. Twenty-three isolates (32%) grew only in rhesus monkey kidney cells, whereas four isolates (6%) grew only in human diploid fibroblasts (MRC-5)(P = .0001). The time to first detection of cytopathic effect was shorter in rhesus monkey kidney cells than in fibroblasts. The extent of cytopathic effect was greater in monkey kidney cells. In conclusion, the addition of rhesus monkey kidney cells increases the yield of varicella-zoster virus and decreases the time required to make a definitive diagnosis. The optimal yield of isolates and time to specific diagnosis occurs when both monkey kidney cells and human diploid fibroblasts are inoculated.

Extrathoracic localization of Legionella pneumophila in Legionnaires' pneumonia.

Extrathoracic organs of 12 fatal cases of Legionnaires' disease from the 1977 Vermont epidemic were reviewed for the presence of Legionella pneumophila. The bacteria were identified by direct immunofluorescence microscopy of paraffin-embedded spleen, liver, lymph node, and kidney tissue. Extrathoracic bacteria were demonstrated in six of the 12 cases (3/7 spleens, 2/9 livers, and 2/10 kidneys). In the liver and spleen, the legionellae were associated with cells of the reticuloendothelial system. In the kidney, the bacteria were restricted to the interstitium and renal tubules. There were no acute inflammatory lesions in any of these organs. The distribution of bacteria in the extrathoracic viscera is compatible with dissemination through the blood stream.

Legionnaires' disease in Vermont. 1972-1976.

One hundred four autopsy cases with previously diagnosed pneumonitis were examined for evidence of Legionnaires' disease. The peak epidemic months of July, August, and September in the five years before the 1977 Vermont epidemic were chosen for study. The bacterium, Legionella pneumophila (serogroup 1) was demonstrated in lung tissue by direct immunofluorescence and the Dieterle silver impregnation stain. There was no clustering of Legionnaires' disease in any one year., The clinical presentation and pulmonary pathology were similar to that of Legionnaires' disease previously reported in Vermont. Seven out of 104 cases were identified as previously undiagnosed Legionnaire's disease. In this time frame, it can be concluded that the disease has been endemic in Vermont.

Immunohistochemical demonstration of Toxoplasma gondii.

A peroxidase-antiperoxidase method that demonstrates both free and encysted toxoplasmata in routinely prepared histologic sections is described. This technic and ultrastructural study were employed to confirm the presence of Toxoplasma gondii in the infected tissues of an immunosuppressed patient who had postmortem examination. An immunohistochemical method may be an aid in the diagnosis of toxoplasmosis.

Legionella and the clinical microbiologist.

Legionella species are important etiologic agents of sporadic and epidemic community-acquired and nosocomial respiratory disease. The list of species continues to expand, and tools for classification and characterization of isolates have become increasingly sophisticated. These organisms are associated with aquatic habitats and are transmitted by aerosol or direct contact. Bacterial culture is the cornerstone of laboratory diagnosis. Careful surveillance of infections is important, because infections potentially can be prevented.

Performance of microtrak direct test for Chlamydia trachomatis in a prevalence study.

Three hundred thirty-two women, aged 18-30 yr. attending two clinics in Burlington Vermont were screened for infection with Chlamydia trachomatis by two methods. Microtrak Direct Test (SYVA) and cell culture. The overall sensitivity for Microtrak compared with culture was 75% (18 of 24), the specificity was 99.7% (307 of 308), the positive predictive value was 94.7% (18 of 19), and the negative predictive value was 98.1% (307 of 313). Prevalence of Chlamydia trachomatis in this population was estimated to be 7.2% (95% confidence intervals 4.4-10.0). The results from this study suggest that Microtrak is less sensitive when used in unselected patient groups from populations of lower prevalence, in contrast to higher sensitivities previously reported.

Evaluation of Uricult dip slide in two hospital populations.

The Uricult dip slide was compared to traditional methods of bacterial isolation and quantitation in two different hospital wards. In a chronic care ward for patients with spinal cord injuries, the correlation of the dip slide and pour plate results was 96 per cent; there were very few specimens which had colony counts between 10(4) and 10(5) per ml. In a busy emergency room, the correlation between the dip slide and quantitative loop techniques was 75 per cent. In this population 18 per cent of the dip slide and 2l per cent of the calibrated loop cultures yielded colony counts between 10(4) and 10(5) per ml., and most of these cultures contained a mixture of bacteria. The results show that the Uricult dip slide performs well under ideal conditions. The dip slide can alleviate, but not eliminate, the problem of mixed bacterial growth at 10(4) to 10(5) colones per ml. The usefulness of the slide must be assessed in relation to the patient population and clinical situation in which it is to be employed.

Detection and characterization of atherosclerotic fibrous caps with T2-weighted MR.

PURPOSE: We assessed the performance of T2-weighted MR imaging in detecting atherosclerotic fibrous caps and in depicting their integrity. METHODS: Twenty atherosclerotic lesions removed by carotid endarterectomy were imaged on a 1.5-T system using T2-weighted spin-echo sequences. The MR images were reviewed independently by four blinded interpreters for fibrous caps and ruptures. The results obtained from the observers were then graded against histologic findings by using receiver-operating characteristic (ROC) curve analysis. RESULTS: The area under the ROC curve for fibrous cap detection was 0.80, indicating that T2-weighted MR imaging was a good but not definitively diagnostic test for detecting ex vivo fibrous caps. The ROC curve for fibrous cap characterization yielded an area of 0.75, indicating that T2-weighted MR imaging was a fair but not highly diagnostic test for depicting fibrous cap integrity. A definite reading for detection of fibrous caps or rupture was fairly specific (90% and 98%, respectively) but not very sensitive (37% and 12%, respectively). CONCLUSIONS: T2-weighted MR imaging of ex vivo atherosclerotic plaques aided in the detection and evaluation of fibrous caps. In both cases, MR imaging proved more useful for ruling out disease than for confirming its presence.

Legionnaires' disease: respiratory infections caused by Legionella bacteria.

This article provides a review of Legionnaire's Disease, a bacterial pneumonia caused by Legionella species, and of Pontiac Fever, the flu-like illness caused by these microorganisms. The authors draw on their personal experience with major human outbreaks of Legionnaire's Disease and with animal models of Legionella pneumonia. Emphasis is placed on the sources in nature from which legionellosis is acquired, the means of dissemination of bacteria, the epidemiology of human infections, the pathogenetic mechanisms of disease and host defense, the clinical manifestations, and the treatment.

Legionnaires' disease in renal transplant patients.

Legionnaires disease, which is commonly manifested as pneumonia, was only recently recognized to be a bacterial infection. Diagnosis can be difficult because Gram's stain does not readily stain the bacterium in pulmonary secretions, the organism is not readily cultured, and legionellae is not affected by many commonly used antibiotics. In a retrospective review of all of our transplant patients, we identified 14 cases of Legionnaires' disease after 101 renal transplants. The patients characteristically had high fever, polymorphonuclear leukocytosis, dyspnea and an unproductive cough accompanied by radiographic changes of consolidating pneumonia. Legionnaires' disease can be diagnosed by direct immunofluorescent antibody staining, culture on special media or increases in serum titers of legionella antibodies in surviving patients. Since the recognition of Legionnaires' disease in 1977, we have successfully treated seven renal transplant patients using erythromycin with or without rifampin.

Enterically transmitted hepatitis. Hepatitis A and E viruses.

Enterically-transmitted hepatitis is caused by hepatitis A virus and hepatitis E virus. The most important agent is hepatitis A virus, which is distributed worldwide and infects all age groups. Most infections in children are minimally symptomatic and immunity is long-lasting, so severe disease tends to occur in nonimmune adults. Hepatitis E virus is found in the developing world and has a greater propensity for symptomatic infection of children. Both agents are transmitted via contaminated water, often through food vehicles.

Rapid diagnosis of Legionnaires' disease.

An enzyme linked immunosorbent assay was developed to detect urinary antigen excreted by patients with Legionnaires' disease. Of 47 patients tested, antigen was detected in 39. Antigen was not detected in any of 178 urine specimens from patients with other pulmonary, bacteremic, or urinary tract infections after performance of a quick and simple confirmatory test. The assay required more time to perform than a previously described radioimmunoassay but was of equivalent sensitivity and specificity and did not require expensive equipment of contact with radioactive reagents. We conclude that enzyme linked immunosorbent assay is a rapid, sensitive, and specific means for rapidly diagnosing Legionnaires' disease which can be performed in clinical laboratories unwilling or unable to use radioisotopes.