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Biomedical subjects

D A Lieberman

Publications and source records attributed to D A Lieberman.

At least 37 records · Page 2Linked to original sources
PubMed1998

Reinforcement without awareness: I. Voice level.

Although some studies have reported that reinforcement can strengthen people's behaviour without their awareness, most studies that have incorporated adequate procedures for assessing awareness have been unsuccessful. Using rigorous procedures, we report two studies designed to provide more scope for learning without awareness by making the reinforcement contingency as unobtrusive as possible. Subjects were told that the experiment was on ESP, and that they were to say which of two words the experimenter was thinking about. In fact, reinforcement was contingent on the loudness of the subject's voice when responding. Even though subjects reported no awareness of a relationship between trial outcomes and their behaviour, the probability of the reinforced responses increased significantly over trials in both experiments. These results support the view that reinforcement can occur without awareness.

Adult↗
PubMed1998

The Web, communication trends, and children's health. Part 1: Development and technology of the Internet and Web.

The Internet and The World Wide Web are changing the way pediatricians find medical information and provide care. This article, the first in a four-part series on The Web, Communication Trends, and Children's Health, published in consecutive issues of this journal, describes how the Web was created and how its multimedia capabilities are affecting information exchange.

Child↗
PubMed1998

The Web, communication trends, and children's health. Part 3: The Web and health consumers.

The World Wide Web has the potential to change significantly how medical care is both delivered and consumed. This, the third of a five-part series on The Web, Communication Trends, and Children's Health, considers how families can use the Internet to find consumer health information and to access care. This article also discusses some of the potential and limitations of Web-based health resources. Part 1 of this series described the development and technology of the Internet and the Web. Part 2 suggested how pediatricians can use the Web to gather medical information and how the increasing capabilities of the Web may affect clinical practice.

Child↗
PubMed1998

The Web, Communication Trends, and Children's Health. Part 5: Encouraging positive and safe Internet use.

The previous four articles in this series on the Web, Communication Trends, and Children's Health (Clinical Pediatrics, March-June, 1998) have shown that the Internet is a rich interactive window on the world, with health-related resources not readily available elsewhere. While the Internet brings great benefits, there are also some significant potential drawbacks. In this final article of the series, we focus on the precautions parents, teachers, and caregivers can take to help children and their families use the Internet wisely and safely.

Child↗
PubMed1998

Serious gastrointestinal pathology found in patients with serum ferritin values < or = 50 ng/ml.

OBJECTIVE: Our aim was to evaluate the gastrointestinal tract in patients with serum ferritin values < or = 50 ng/ml for the presence of serious gastrointestinal pathology, including neoplasia and acid peptic disease. METHODS: In this prospective observational study, patients with serum ferritin values < or = 50 ng/ml who did not have an obvious cause of iron deficiency underwent colonoscopy and/or esophagogastroduodenoscopy. RESULTS: Between October 1, 1994, and February 29, 1996, 725 of 3015 patients who had serum ferritin determinations were found to have values < or = 50 ng/ml. To date, 143 patients have been fully evaluated and 77 were found to have serious gastrointestinal pathology including acid peptic disease (N = 46), cancer (N = 15), and large adenomas (N = 6). Colon cancer was discovered in five asymptomatic patients. The prevalences of serious gastrointestinal pathology did not differ between patients with serum ferritin values < or = 20 ng/ml and those with values between 21-50 ng/ml (63% vs 48%, p = 0.07). However, multivariate analysis showed that the presence of upper or lower gastrointestinal symptoms and serum ferritin value < or = 20 ng/ml is predictive of finding serious pathology (p = 0.0002 for the whole model), with odds ratios of 3.8 (95% confidence interval of 1.84-7.70) for presence of gastrointestinal symptoms and 2.2 (95% confidence interval of 1.09-4.57) for serum ferritin value < or = 20 ng/ml. CONCLUSIONS: Endoscopic examination is warranted in patients with serum ferritin values < or = 50 ng/ml to detect serious gastrointestinal pathology, present in 54% of such patients.

Aged↗
PubMed1997

The prevalence of colonic neoplasia in patients with Barrett's esophagus: prospective assessment in patients 50-80 years old.

OBJECTIVE: An association between Barrett's esophagus and colorectal neoplasia has been suggested; however, several studies addressing this issue have reported conflicting results. The purpose of this study, therefore, was to determine the prevalence of colorectal neoplasia in a large group of patients (50-80 yr old; mean, 65 yr) with Barrett's esophagus and compare it with that of a similar group of asymptomatic, average-risk controls. METHODS: Seventy-nine subjects (71 men, eight women) with well-documented Barrett's esophagus underwent complete colonoscopy (cecum reached), which was performed as part of an initial screening evaluation for enrollment in a prospective study of Barrett's esophagus. The control population (N = 930) is represented by the cumulative results of four recent studies in which screening colonoscopy was performed in asymptomatic subjects of average risk. The age of the two groups were similar. RESULTS: A total of 38 adenomatous polyps were found in 26 patients in the study group. Three patients (4%) had polyps > 1 cm in size or with villous change, which was similar to the prevalence among asymptomatic controls (5%). The overall prevalence of colon adenomas was 32%, and the prevalence of colorectal cancer was 1% in the Barrett's group. In the control group, 30% had adenomas and 0.5% had cancer. CONCLUSION: The prevalence of adenomatous polyps, both large and small, in a group of patients (ages 50-80 yr) with well-documented Barrett's esophagus is no different from that in asymptomatic controls. These results do not support the assumption of an association between Barrett's esophagus and an increased risk of colon neoplasia, or justify an aggressive surveillance strategy for colon neoplasia in patients with Barrett's esophagus.

Adenomatous Polyps↗
PubMed1997

Risk factors for Barrett's esophagus in community-based practice. GORGE consortium. Gastroenterology Outcomes Research Group in Endoscopy.

OBJECTIVES: Endoscopy is often performed in patients with gastroesophageal reflux (GER) disease because of concern about the presence of Barrett's esophagus (BE). The purpose of this study was to determine whether the duration of GER symptoms and/or a history of esophagitis was associated with an increased risk of BE. METHODS: This was an observational, prospective, community-based study. Consecutive patients undergoing elective endoscopy because of GER symptoms were enrolled. Endoscopy reports and pathological findings were reviewed to classify patients as having no esophagitis, esophagitis, or probable BE. Correlations with duration of symptoms and a history of esophagitis were analyzed. RESULTS: In all, 701 of 2641 patients (27%) undergoing elective endoscopy had GER symptoms, and 77 of these patients had probable BE. Compared with patients with GER symptoms for less than 1 yr, the odds ratio for BE in patients with GER symptoms for 1-5 years was 3.0 and increased to 6.4 in patients with symptoms for more than 10 yr (p < 0.001). A history of esophagitis was not an independent risk factor for BE (p = 0.17). CONCLUSIONS: Prevalence of BE is strongly associated with duration of GER symptoms.

Adolescent↗
PubMed1996

Effect of oral sodium phosphate colon preparation on serum electrolytes in patients with normal serum creatinine.

BACKGROUND: Oral sodium phosphate is commonly used for colon preparation prior to colonoscopy. Several studies have demonstrated significant changes in serum electrolytes after sodium phosphate preparation, but failed to stratify patients with regard to renal function. The purpose of this study was to determine if electrolyte alterations are observed after sodium phosphate in patients with normal levels of serum creatinine. METHODS: Thirty-two patients scheduled for elective colonoscopy who had a serum creatinine level of less than 1.5 mg/dL were enrolled. All patients had a panel of laboratory studies prior to and immediately after receiving oral sodium phosphate colon preparation. RESULTS: Significant increases in serum phosphate and sodium and decreases in serum calcium and potassium were observed. Twenty-eight percent of patients had serum phosphate levels greater than 8.0 mg/dL, and 6% of patients had serum calcium levels less than 8.0 mg/dL after sodium phosphate colon preparation. There were no clinically apparent adverse events. CONCLUSIONS: Significant changes in serum electrolyte levels occur after sodium phosphate colon preparation in patients with normal serum creatinine levels. Sodium phosphate could exacerbate pre-existing hypocalcemia or hypokalemia in patients with apparently normal renal function. Therefore, it may be prudent to evaluate serum electrolytes prior to administration of sodium phosphate.

Administration, Oral↗
PubMed1996

Complications related to endoscopic hemostasis techniques.

Endoscopic therapy has had a significant impact on the management of bleeding peptic ulcers and varices. Therapy is effective at stopping immediate bleeding and has been shown to improve key patient outcomes. Ulcer therapy has few significant complications, whereas variceal therapy is fraught with serious complications, which are reviewed.

Electrocoagulation↗
PubMed1995

Cost-effectiveness model for colon cancer screening.

BACKGROUND & AIMS: The relative efficacy and effectiveness of different colon screening programs has not been assessed. The purpose of this analysis was to provide a model for comparing several colon screening programs and to determine the key variables that impact program effectiveness. METHODS: Five screening programs were compared: annual fecal occult blood test (FOBT) alone, flexible sigmoidoscopy, flexible sigmoidoscopy and FOBT combined, one-time colonoscopy, and air-contrast barium enema. Key variables were adjusted for sensitivity analyses. Cost-effectiveness was defined as the cost per cancer death prevented. RESULTS: FOBT alone prevents fewer cancer deaths than the other programs. The addition of flexible sigmoidoscopy to the FOBT increases the rate of cancer prevention. One-time colonoscopy has the greatest impact on colorectal cancer mortality, largely because of assumptions that cancer would be prevented in most patients who undergo polypectomy. FOBT alone is the most cost-effective of the programs, but the cost is sensitive to several key variables. CONCLUSIONS: The model shows key variables that impact the cost-effectiveness of colon screening programs. Compliance is an important determinant of effectiveness of all of the screening programs. Future study should be focused on methods of patient education that improve patient compliance with screening.

Aged↗
PubMed1995

Prevalence and natural history of colonic angiodysplasia among healthy asymptomatic people.

OBJECTIVE: The prevalence of colonic angiodysplasia (AD) among healthy asymptomatic people is unknown, and the natural history of these lesions has not been clearly defined. The purpose of our study was to determine prevalence and to review and assess the natural history of AD. METHODS: Each of the authors had previously published his own prospective study that involved screening colonoscopy for the detection of neoplasia in asymptomatic adult men and women who had never bled. All pathological lesions diagnosed by endoscopy were recorded, but only data pertaining to polyps were published. We pooled and analyzed the endoscopic findings (raw data) from those studies and assessed the natural history of the lesions by reviewing the medical charts of affected subjects to determine whether bleeding had occurred. Nine hundred sixty-four patients were evaluated (mean age, 62 yr). All were > or = 50 yr old (range, 50-79 yr), not anemic, Hemoccult negative, asymptomatic, and had full colonoscopy to the cecum. RESULTS: Eight subjects had AD (prevalence, 0.83%). Lesions in affected individuals were usually small (mean size, 4.0 mm) and most often were located in the right colon (62%). No subject bled, and all maintained a stable hemoglobin (mean, 14.6 g%) with a mean follow-up of 3 yr. CONCLUSIONS: We conclude that 1) colonic AD is uncommon among healthy asymptomatic people (prevalence, 0.83%), 2) lesions are usually small (< 10 mm) and are located proximal to the hepatic flexure, 3) the natural history for AD in these people is benign, and the risk of bleeding over a 3-yr period is low (0% in 3 yr), and 4) because of this low risk, endoscopic treatment for incidental (nonbleeding) AD is unnecessary.

Aged↗
PubMed1992

Physician assistants in gastroenterology: should they perform endoscopy?

New technology and increased screening examinations continue to cause the demand for gastrointestinal endoscopic procedures to mushroom. Hospitals administered by the Department of Veterans Affairs, public health care facilities, and health maintenance organizations struggle to meet this demand because of limited resources for expansion of space or staff. For the past 3 yr, we have used a physician assistant in our endoscopy laboratory to assist with and perform endoscopic procedures. The benefits for our hospital include increased staff efficiency, improved housestaff education, and ability to perform an increased number of procedures with existing staff.

Endoscopy, Gastrointestinal↗
PubMed1992

Targeted colon cancer screening: a concept whose time has almost come.

Screening of large populations for colon malignancy has been advocated in several countries to detect cancers at earlier, curable stages and/or prevent cancer by detecting and removing premalignant polyps. Ideal screening would identify subjects with the highest risk of cancer and target sensitive screening tests at this population. Recent data suggesting that environmental factors and genetic alterations contribute to increased cell proliferation in colonic mucosa provide several avenues for identification of high-risk subjects. This review examines the current literature regarding colon cancer risk factors, focusing on new ways to identify individuals who may benefit from targeted screening.

Biomarkers, Tumor↗
PubMed1991

Screening for colon malignancy with colonoscopy.

Screening of asymptomatic individuals for colon malignancy has been advocated for the past 20 yr in the hopes of reducing colon cancer mortality. Although sigmoidoscopy is an important element of current screening recommendations, the sensitivity of this test in asymptomatic subjects has never been studied. The purpose of this study was to determine the prevalence and location of polyps and cancers in an asymptomatic population by performing full colonoscopy. We wished to assess the sensitivity of screening flexible sigmoidoscopy to 60 cm by determining how many patients with adenomas or cancer had "index" adenomatous polyps in the distal 60 cm. One hundred five healthy male outpatients, over 50 yr old, with negative examinations for occult blood in stools and no prior history of colon pathology, had full colonoscopy. Careful examination of the distal 60 cm was performed, followed by a full colon examination to the cecum. Forty-three patients (41%) had adenomatous polyps, and only 19 of these patients had an index adenomatous polyp in the distal 60 cm. Therefore, the sensitivity of sigmoidoscopy was 44%. The prevalence of adenomas increased with age. Patients were assigned to one of three groups based on the findings in the distal 60 cm. Group 1 (n = 65) had no polyps in the distal 60 cm, but 18 of these patients (28%) had adenomatous polyps in the proximal colon. Among 21 patients with only hyperplastic polyps in the distal 60 cm (group 2), six patients (29%) had proximal adenomas. In group 3, eight of 19 patients (42%) with adenomas in the distal 60 cm also had proximal adenomatous polyps. We conclude that adenomatous polyps are common in asymptomatic men who have negative tests for fecal occult blood. Sigmoidoscopy to 60 cm had a sensitivity of only 44% in this patient population, suggesting that this is an insensitive test for the detection of patients with adenomatous polyps.

Aged↗
PubMed1990

Colon cancer screening. The dilemma of positive screening tests.

Despite doubts about the benefits of colon cancer screening, sigmoidoscopy and fecal occult blood tests are now often performed by clinicians who must then deal with positive test results. The purpose of this literature review is to examine potential strategies for dealing with positive screening test results. If positive results are obtained, current data support the use of colonoscopy as the single most effective diagnostic strategy. Exceptions include situations that reduce the predictive value of the screening test. Several important areas of controversy are highlighted that need to be assessed in subsequent studies.

Colonic Neoplasms↗