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Biomedical subjects

Jeffrey P Baker

Publications and source records attributed to Jeffrey P Baker.

12 recordsLinked to original sources
PubMed2006

A patient with anemia of obscure origin: Crohn's disease in disguise.

BACKGROUND: A 65-year-old white Mediterranean male with a 10-year history of intermittent anemia, who was otherwise completely asymptomatic, was referred to our hospital in March 2004. He had a medical history of beta thalassemia and fecal occult blood tests had occasionally been positive. INVESTIGATIONS: Fecal occult blood test, laboratory investigations, esophagogastroduodenoscopy, colonoscopy with retrograde ileoscopy, mesenteric angiography, small-bowel series, CT scan of the abdomen and pelvis, Meckel's scan, and capsule endoscopy. Laparoscopic surgery followed by macroscopic and microscopic histopathologic examination of samples obtained during the procedure. DIAGNOSIS: Crohn's disease of the small bowel. MANAGEMENT: Laparoscopic segmental small-bowel resection with end-to-end anastomosis. Postsurgical treatment with Pentasa 4 g a day.

Aged↗
PubMed2005

Capsule endoscopy findings in patients with established and suspected small-bowel Crohn's disease: correlation with radiologic, endoscopic, and histologic findings.

BACKGROUND: Little is known about the accuracy of capsule endoscopy (CE) in evaluation of small-bowel Crohn's disease. METHODS: Symptomatic eligible patients had ileocolonoscopy and biopsies from the terminal ileum, followed by small-bowel radiologic studies before CE. Endoscopic, radiologic, CE, and histologic findings were compared. Histology (terminal ileum biopsy specimens or a tissue sample after small-bowel resection) served as a criterion standard. RESULTS: Fifty-four patients were enrolled; 15 of the 54 patients were excluded from data analysis (critical small-bowel strictures, 14, identified on radiology; incomplete CE, 1). Data were analyzed for 39 patients. All patients had histologic evaluation of the small bowel. Final diagnosis of active small-intestine Crohn's disease was made in 29/39 patients (74.4%). When calculated, CE yielded a sensitivity and a specificity of 89.6% and 100.0%, respectively, and a positive predictive value and a negative predictive value of 100.0% and 76.9%, respectively, whereas small-bowel series were 27.6%/100.0% and 100.0%/32.3%. CONCLUSIONS: CE is more accurate in detecting small-bowel inflammatory changes suggestive of Crohn's disease than conventional studies. CE, combined with ileocolonoscopy, may be proposed as a first-line investigation of the small intestine in cases of uncomplicated known or suspected Crohn's disease.

Adult↗
PubMed2005

Lessons from the past.

This article considers errors of care in neonatology. In the 19th century errors that resulted in high infant mortality were shaped by the social environment, and in this setting the development of the incubator failed. In the early 20th century, with the emergence of the modern hospital as a technological, science-driven system, physicians had more control of patients' environments, and thus medical errors could occur from systematic care and affected larger numbers. Later in the 20th century, the development of randomized controlled trials and systematic reviews began to improve care and to decrease the risks associated with new treatment methods. Large variations in practice still exist between physicians as individuals and institutions. Considering these variations as risks has led to the use of institutional databases, benchmarking and clinical care guidelines. The efficacy and safety of these methods is unproven. Risks will never disappear from medicine. The question of what risks are 'acceptable' is, in general, unanswerable.

Benchmarking↗
PubMed2005

Given capsule endoscopy in celiac disease: evaluation of diagnostic accuracy and interobserver agreement.

BACKGROUND AND AIMS: Capsule endoscopy (CE) has been increasingly used for diagnosing diseases of the small bowel. It is an attractive technique for assessing celiac disease (CD) because it is noninvasive and provides a close and magnified view of the mucosa of the entire small bowel. In this study, we evaluated the accuracy of CE and interobserver agreement in recognizing villous atrophy (VA) using histopathology as the reference. We also explored the extent of small bowel involvement with CD and the relationship between the length of the affected bowel and the clinical presentation. METHODS: Ten CD patients with histologically proven VA and the same number of controls were subjected to CE. Four, blinded to histology findings, investigators (two with and two without prestudy CE experience) were asked to diagnose VA on CE images. RESULTS: Based on assessment of all four investigators, the overall sensitivity, specificity, PPV, and NPV of CE in diagnosing VA were 70%, 100%, 100%, and 77%, respectively. The sensitivity and the specificity of the test was 100% when the reports of experienced capsule endoscopists only were analyzed. The interobserver agreement was perfect (kappa= 1.0) between investigators with prestudy CE experience and poor (kappa= 0.2) between the investigators who had limited prestudy exposure to CE. Celiac patients with extensive small bowel involvement had typical symptoms of malabsorption (diarrhea, weight loss) as opposed to mild and nonspecific symptoms in patients whose disease was limited to the proximal small bowel. CE was tolerated well by all study participants with 95% reporting absence of any discomfort. CONCLUSIONS: Although based on a small sample size, the study suggests that CE may be useful in assessing patients with CD. Familiarity with CE technology appears to be a critical factor affecting the accuracy of the test. Larger studies are warranted to more precisely define the advantages and limitations of CE in CD.

Atrophy↗
PubMed2003

Childhood vaccine development: an overview.

Vaccines against childhood diseases represent some of the most important applications of 20th-century pediatric research. This survey examines how the components of the current U.S. immunization schedule emerged in three phases during the course of the century. The first phase, after the development of bacterial culture techniques, witnessed numerous efforts in the early 1900s to develop bacterial vaccines. It proved most fruitful with respect to diphtheria, tetanus, and pertussis. The rise of viral tissue culture techniques in the 1950s brought about a second phase of innovation resulting in vaccines against polio, measles, mumps, rubella, and varicella. A third wave of innovation, still very much alive, has drawn on a variety of new technologies and led to vaccines against hepatitis B, Haemophilus influenzae type b, pneumococcus, and still other organisms. Although basic science research has thus been a primary factor shaping the history of vaccine development, the collaboration between the academic, private, and public sectors critical to its application has not always proceeded smoothly. The history of vaccine research and development has important implications for today, as a variety of factors threaten to fragment this network.

Bacterial Vaccines↗
PubMed2003

The pertussis vaccine controversy in Great Britain, 1974-1986.

This historical essay analyzes the role played by Great Britain in the pertussis vaccine controversy of the 1970s and 1980s. Public backlash against this vaccine not only took place earlier in Britain than the United States, but also was so widespread that a series of whooping cough epidemics soon followed. As with the more recent dispute involving measles-mumps-rubella (MMR) vaccine and autism, the United Kingdom played a primary role in defining, promoting, and ultimately exporting this controversy. This essay seeks to explain this phenomenon by situating it in Britain's long history of suspicion regarding vaccines evident among both the public and the medical profession, a theme dating back to the compulsory vaccination laws of the 19th century. It argues that anti-vaccinationism, far from being simply a new development related to the public's lack of awareness of childhood vaccine-preventable illness, actually represents a revival of a much older movement.

Disease Outbreaks↗
PubMed2003

GRP94/gp96 elicits ERK activation in murine macrophages. A role for endotoxin contamination in NF-kappa B activation and nitric oxide production.

Vaccination of mice with GRP94/gp96, the endoplasmic reticulum Hsp90, elicits a variety of immune responses sufficient for tumor rejection and the suppression of metastatic tumor progression. Macrophages are a prominent GRP94/gp96 target, with GRP94/gp96 reported to activate macrophage NF-kappa B signaling and nitric oxide production, as well as the MAP kinase p38, JNK, and ERK signaling cascades. However, recent studies report that heat shock protein elicited macrophage activation is due, in large part, to contaminating endotoxin. To examine the generality of this finding, we have investigated the role of endotoxin in GRP94/gp96-elicited macrophage activation. We report that GRP94/gp96 binds endotoxin in a high-affinity, saturable, and specific manner. Low endotoxin calreticulin and GRP94/gp96 were purified, the latter using a novel method of depyrogenation; this resulted in GRP94/gp96 and calreticulin preparations with endotoxin levels substantially lower than those of previously reported preparations. Low endotoxin GRP94/gp96 retained its native conformation, ligand binding activity, and in vitro chaperone function, yet did not activate macrophage NF-kappa B signaling, nitric oxide production or inducible nitric-oxide synthase production. Low endotoxin GRP94/gp96 and calreticulin did, however, elicit a marked increase in ERK phosphorylation at protein concentrations as low as 2 microg/ml. These results are discussed with respect to current understanding of the contributions of endotoxin and heat shock/chaperone proteins to the stimulation of innate immune responses.

Animals↗