tbuckley/cabot-search huggingface dataset:
Readers guide to critical appraisal of cohort studies: 3. Analytical strategies to reduce confounding
Authors: Sharon-Lise T Normand, Kathy Sykora, Ping Li, Muhammad Mamdani, Paula A Rochon, Geoffrey M Anderson
Journal: BMJ (2005)

Analytical strategies can help deal with potential confounding but readers need to know which strategy is appropriate 

The previous articles in this series1 2 argued that cohort studies are exposed to selection bias and confounding, and that critical appraisal requires a careful assessment of the study design and the identification of potential confounders. This article describes two analytical strategies—regression and stratification—that can be used to assess and reduce confounding. Some cohort studies match individual participants in the intervention and comparison groups on the basis of confounders, but because matching may be viewed as a special case of stratification we have not discussed it specifically and details are available elsewhere.3 4 Neither of these techniques can eliminate bias related to unmeasured or unknown confounders. Furthermore, both have their own assumptions, advantages, and limitations.

Regression uses the data to estimate how confounders are related to the outcome and produces an adjusted estimate of the intervention effect. It is the most commonly used method for reducing confounding in cohort studies. The outcome of interest is the dependent variable, and the measures of baseline characteristics (such as age and sex) and the intervention are independent variables. The choice of method of regression analysis (linear, logistic, proportional hazards, etc) is dictated by the type of dependent variable. For example, if the outcome is binary (such as occurrence of hip fracture), a logistic regression model would be appropriate; in contrast, if the outcome is time to an event (such as time to hip fracture) a proportional hazards model is appropriate.

Regression analyses estimate the association of each independent variable with the dependent variable after adjusting for the effects of all the other variables. Because the estimated association between the intervention and outcome variables adjusts …
Antitumor and Toxic Effects of Combination Chemotherapy With Bleomycin and a Phenothiazine Anticalmodulin Agent1
Authors: W. N. Hait, J. S. Lazo, D.-L. Chen, V. S. Gallichio, A. E. Filderman
Journal: JNCI Journal of the National Cancer Institute (1988)

Phenothiazines and structurally related calmodulin antagonists acted synergistically with blemycin in killing malignant cells in culture. For exploration of the potential clinical importance of this observation, the effects of administering the combination of chlorpromazine and bleomycin in vitro and in vivo against the transplantable B16 melanoma were studied. The toxicity of the combination to bone marrow and lungs was also determined. Combined chlorpromazine and bleomycin therapy reduced the concentration of chlorpromazine required to inhibit cellular growth of B16 melanoma cells by greater than half (25 vs. 60μM). Against the transplanted tumor, after 3 weeks of treatment the tumor sizes )in cubic millimeters) were 540 ± 100 (vehicle), 520 ± 120 (chlorpromazine), 170 ± 10 (bleomycin), and 80±20 (blemmycin + Chlorpromazine, P<.01 vs. blemycin alone). The median time required to reach a tumor size of 100 mm3 was 15 days for vehicle and chlorpromazine, 17 days for bleomycin, and 26 days for chlorpromazine and bleomycin together. The doubling time of the tumor was also increased 3.5-fold above control with the two-drug combination. At doses of bleomycin and chlorpromazine that increased antitumor activity, no pulmonary fibrosis, measured histologically and biochemically, was detected. At higher doses of bleomycin, the addition of chlorpromazine diminished lung fibrosis. The combination of drugs was not more toxic to hematopoietic precursors than chlorpromazine alone. Tjese studies suggested that the addition of a phenothiazine to blemycin can augment the therapeutic efficacy of bleomycin in vivo without substantially increasing its toxicity. [J Natl Cancer Inst 1988;80:246–250]
A painful rash
Authors: T. M Monaghan, J. D Thomas, W. Goddard
Journal: BMJ (2009)

A 54 year old man presented with a flare of Crohn’s disease. He had developed a painful red rash on his face, neck, and shoulders one week prior to this flare. Clinical examination showed multiple tender erythematous plaques with superadded pustules and surrounding erythema. Laboratory investigations showed a white cell count of 15×109/l—essentially neutrophilia—and a C reactive protein concentration of 106 mg/l. Blood tests were otherwise unremarkable. The patient is shown 10 days after onset of the rash, when the lesions were beginning to resolve.⇓ ⇓



Fig 1 Frontal photograph of the patient’s forehead 10 days after the onset of the rash 





Fig 2 Close up photographs of two of the facial lesions 





### Short answers

### Long answers

#### 1 Sweet’s syndrome

Sweet’s syndrome, also known as acute febrile …
Diseases of the Liver and Biliary System
Authors: Frank Iber
Journal: JAMA (1997)

This classic text, which first appeared in 1963, is the foremost liver book in the world by only one or two authors. The current edition has the same chapter headings as the ninth (1993) and is almost the same length, but this is accomplished by adding new information where important changes are warranted (chronic hepatitis is markedly expanded) and decreasing the space allotted to sections that have not changed. The book is aimed at all physicians who are not liver specialists. It is written for those who treat and advise patients and, as such, all that is required is included, and all that is not required is excluded. In the last several editions, cartoons, line drawings, flow charts, and concept diagrams have been widely included to present mechanisms or approaches to disease while saving detailed presentation in the text, and in this manner much basic science information is imparted in
Input-driven behavior: One extreme of the multisensory perceptual continuum
Authors: Kelvin S. Oie, John J. Jeka
Journal: Behavioral and Brain Sciences (2001)

The propositions that the senses are separate and that the global array may be sufficient for adequate perception are questioned. There is evidence that certain tasks may be primarily “input-driven,” but these are a special case along the behavioral continuum. Many tasks involve sensory information that is ambiguous, and other sources of information may be required for adequate perception.
Manipulation of glutathione stores in rat hepatic stellate cells does not alter collagen synthesis
Authors: J J Maher, B A Neuschwander-Tetri
Journal: Hepatology (1997)

Hepatic stellate cells are resistant to the fibrogenic effects of lipid hydroperoxides in primary culture. Recent studies from our laboratory suggest that antioxidants, particularly glutathione, play a role in this resistance. We have observed that glutathione accumulates rapidly in stellate cells during primary culture; in the current study, we investigated whether glutathione modulates stellate cell collagen synthesis. Stellate cells from normal rat liver were plated in primary culture and maintained for 7 days. From day 4 through day 7, the cells were treated with L-buthionine sulfoximine (BSO) to deplete glutathione stores. BSO profoundly diminished stellate cell glutathione but had no effect on morphology, viability, or basal levels of collagen synthesis and gene expression. When cultured stellate cells were incubated with the putative fibrogenic mediator 4-hydroxynonenal or iron/ascorbate, little or no increase in collagen synthesis occurred regardless of glutathione content. In contrast, iron/ascorbate induced collagen synthesis by cultured fibroblasts. The data indicate that stellate cells strongly resist oxidant- and lipid peroxide-induced collagen synthesis in primary culture. They demonstrate that the mechanism of this resistance does not involve glutathione.
The targeting of 14-succinate triptolide-lysozyme conjugate to proximal renal tubular epithelial cells
Authors: Zhirong Zhang, Qiang Zheng, Jing Han, Guangping Gao, Jie Liu, Tao Gong, Zhongwei Gu, Yuan Huang, Xun Sun, Qin He
Journal: Biomaterials (2008)
Filles de Kilimanjaro III (Miles Davis)
Authors: Thomas B. Cole
Journal: JAMA (2013)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal
DEVELOPMENT OF 3-DIMENSIONAL IMAGE INTERPOLATION METHODS FOR MAGNETIC RESONANCE IMAGES OF THE HEART
Authors: R. F. Johnson, D. G. Brunder
Journal: Clinical Nuclear Medicine (1992)

S: APRIL 9–12, 1992 San Antonio Convention Center & Hyatt Regency Hotel SAN ANTONIO, TEXAS Southwestern Chapter Society of Nuclear Medicine SPECT/PET Nuclear Cardiology Symposium and 37th Annual Meeting: PDF Only
Pitfalls of statistical hypothesis testing: type I and type II errors
Authors: P. Sedgwick
Journal: BMJ (2014)

Researchers investigated the effects of a multidimensional lifestyle intervention on aerobic fitness and adiposity in predominantly migrant preschool children. A cluster randomised controlled trial study design was used. Intervention included a physical activity programme, plus lessons on nutrition, media use (use of television and computers), and sleep and adaptation of the built environment of the preschool class. The study lasted from August 2008 to June 2009. The control group did not receive any intervention and continued their regular school curriculum, which included one 45 minute physical activity lesson a week in the gym.1 In total, 40 preschool classes were recruited in areas with a high migrant population in the German and French speaking regions of Switzerland. Classes were randomised to intervention or control after stratification for linguistic region. The primary outcomes were aerobic fitness as measured by the 20 minute shuttle run test and body mass index (BMI). Secondary outcomes included motor agility, percentage body fat, and waist circumference. The critical level of significance for statistical testing was set at 0.05 (5%). Intervention resulted in significantly increased aerobic fitness compared to control (intervention minus control) (mean difference: 0.32 stages; 95% confidence interval 0.07 to 0.57; P=0.01), but no difference in BMI (−0.07 kg/m2, −0.19 to 0.06; P=0.31). The authors concluded that a multidimensional intervention increased aerobic fitness and reduced body fat but not BMI in predominantly migrant preschool children. Which of the following statements, if any, are true?
Normal Esophageal and Gastric Electrocardiograms
Authors: ALBERT D. KISTIN, WARREN D. BRILL, GEORGE P. ROBB
Journal: Circulation (1950)

An analysis of normal esophageal and gastric electrocardiograms is presented. Some standards of abnormality in the literature are found to be unacceptable, principally with reference to Q and the diagnosis of infarction. The study of leads facing the dorsal and diaphragmatic cardiac surfaces seems to be a suitable test of current concepts of "electrocardiographic position." Some of these concepts are supported by this study, but others are questioned.
Monitoring of controlled drugs in England is still lacking in some aspects, commission finds
Authors: R. Dobson
Journal: BMJ (2008)

Monitoring of controlled drugs in England has improved in the wake of the Shipman inquiry, but more work is still needed to minimise the risk of misuse by doctors, a new report concludes.

The report warns of a lack of confidence in sharing concerns about named professionals and of unclear lines of responsibility in some areas.

“Healthcare services have taken the first steps in minimising the risk of another Shipman,” said Anna Walker, chief executive of the Healthcare Commission, whose report details what has been done to improve monitoring since new regulations came into force in England last year. The regulations were a response to the conviction of the Manchester GP Harold Shipman …
Acute Lymphoblastic Leukemia Terminating as Histiocytic Medullary Reticulosis
Authors: David P. Shreiner
Journal: JAMA (1975)

A young man with acute lymphoblastic leukemia was treated with vincristine sulfate, prednisone, and intrathecally injected methotrexate sodium for central nervous system involvement. A good remission was induced, but three months later he had hepatosplenomegaly, an enlarging mediastinal mass, and progressive anemia. Histiocytic medullary reticulosis was confirmed by a bone marrow biopsy specimen. The patient died of respiratory failure because of infiltration of the lungs by malignant histiocytes. (<i>JAMA</i>231:838-840, 1975)
Recruiting in hard times
Authors: J. Rogers
Journal: BMJ (1997)

Medical manpower shortages are upon us with a vengeance. They have occurred for a variety of reasons: poor medical manpower planning, trusts' opportunistic business developments, the New Deal, changes to the content and requirements of training posts, early retirements, the employment of more women doctors, and the accreditation requirements of some of the royal colleges. The list is not exhaustive - but while the reasons for shortages are many, the final result is now clear - a medical manpower crisis with the potential for far reaching consequences for hospital services in particular, with shortages often at their worst in those parts of the country where health is the poorest.

The focus of this article is upon some best practice in the recruitment of senior medical staff. It is written from my perspective as chief executive of a trust, but in particular should have value for medical directors of trusts.

I would like to have said that pay is not critical to the recruitment of senior medical staff, but it would not be strictly true. I have had some grim and greedy discussions with consultant medical staff seeking trust appointments in the past, and it has taught me a lot. While some salary enhancement can be accommodated through a genuine leadership contribution, my view is that, as a general rule, trusts would do well to steer clear of differential pay. The kind of doctor who is motivated to join a trust and a clinical team purely for monetary reasons is not the kind of doctor most trusts benefit from, nor is he or she usually a good long term bet. Moreover, inflated pay deals create a poor image of a trust, its management, and its values. Good medical staff may well wonder what kind of doctor wants to …
Oral Hydrocortisone Therapy in Rheumatoid Arthritis: An Appraisal of General Results of Prolonged Administration
Authors: E. W. Boland
Journal: Annals of the Rheumatic Diseases (1955)

The binding of vitamin B<sub>12</sub> by human gastric juice has been found to be <i>p</i>H dependent. Maximum binding occurs between <i>p</i>H 6·5 and 10. Outside this <i>p</i>H range the vitamin B<sub>12</sub>-binding ability of human gastric juice decreases and at <i>p</i>H below 2 or above 12·2 this drops sharply to about 10 to 15% of the maximum. Three commercial hog intrinsic factors have been found to give a similar response to <i>p</i>H changes. The <i>p</i>H-dependent binder in human gastric juice has been shown to be intrinsic factor by the addition of intrinsic factor-blocking antibody. About 10% of vitamin B<sub>12</sub> bound by human gastric juice is not bound by intrinsic factor and is not <i>p</i>H dependent. The reduction in the vitamin B<sub>12</sub>-binding capacity of human gastric juice induced by an adverse <i>p</i>H is reversed by neutralization. The physiological and clinical significance of these observations is discussed and their relevance to various procedures <i>in vitro</i> noted.
Bowel necrosis induced by tumor necrosis factor in rats is mediated by platelet-activating factor.
Authors: X M Sun, W Hsueh
Journal: Journal of Clinical Investigation (1988)

We have developed a rat model of ischemic bowel necrosis associated with shock by injection of platelet-activating factor (PAF) or a combination of PAF and endotoxin. Recent investigations have shown that tumor necrosis factor (TNF) also induces shock and necrosis of the gastrointestinal tract. The morphological changes of TNF-induced bowel lesions are indistinguishable from those caused by PAF. The mechanism of TNF-induced bowel necrosis is unclear. In the present study, we have shown that (a) TNF caused PAF production in bowel tissue; (b) the effects of TNF and LPS on PAF production in the intestine are additive; (c) TNF and LPS are synergistic in inducing bowel necrosis; and (d) TNF-induced bowel necrosis is due to PAF release and can be prevented by pretreatment with PAF antagonists.
Biomarkers for Prediction of Cardiovascular Events
Authors: Nancy R. Cook
Journal: JAMA (2009)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal
Devolution in Latin America has had poor effects on health care
Authors: P. Sandiford
Journal: BMJ (1999)

EDITOR—The Editor's choice of 1 May expressed “excitement” at the possible effects of devolution on health care in the United Kingdom.1 Had the experiences of some Latin American countries been examined in addition to those of Canada, Spain, and Finland, apprehension might have been a more appropriate sentiment.

Within Latin America, Chile, Brazil, Mexico, and Bolivia have all experimented with devolution of publicly funded health services to subnational government bodies. In these countries, as in the United Kingdom, the motives for …
Solving the Shortage of Primary Care Physicians
Authors: William A. Hensel
Journal: JAMA (1993)

<h3>To the Editor.</h3> —The drift of American medicine to the point of great imbalance between the supplies of specialist and generalist physicians has led to a willingness on the part of some medical leaders to consider drastic "solutions" to this problem. How else would one interpret the Editorial by Drs Lundberg and Lamm<sup>1</sup>proposing that we teach specialists certain competencies in order to rename them primary care providers and that we require national service for our medical school graduates? Discounting for now whether or not these remedies are achievable, it is prudent to ask whether they should even be attempted. The retraining of specialists to provide primary health care overlooks the reasons why these physicians initially chose to be specialists or generalists. To suggest that compensation changes and remedial education will result in a greater supply of primary care providers requires a leap of faith and perpetuates the stereotype
Impact of Body-Size Measures on Irinotecan Clearance: Alternative Dosing Recommendations
Authors: Ron H.J. Mathijssen, Jaap Verweij, Maja J.A. de Jonge, Kees Nooter, Gerrit Stoter, Alex Sparreboom
Journal: Journal of Clinical Oncology (2002)

PURPOSE: To evaluate relationships between various body-size measures and irinotecan (CPT-11) clearance and metabolism in cancer patients, and to provide future dosing recommendations for this agent. PATIENTS AND METHODS: Pharmacokinetic data were obtained from 82 adult patients (50 men, 32 women; median age, 54 years) receiving CPT-11 as a 90-minute intravenous infusion (dose range, 175 to 350 mg/m2). In each patient, plasma samples were collected at timed intervals in the first administration of a 3-week schedule, and CPT-11 and its metabolite, SN-38, were measured by a liquid chromatographic assay. RESULTS: The mean (± SD) CPT-11 clearance was 33.6 ± 10.8 L/h, with an interindividual variability (IIV) of 32.1%. When clearance was adjusted for body-surface area (BSA), the IIV was similar (34.0%). In addition, in a multiple linear regression analysis, none of the studied measures (BSA, lean body mass, [adjusted] ideal body weight, and body mass index) was a significant covariate (P > .13; r2 < .014) in our population. Similarly, BSA did not significantly contribute to variability in the relative extent of conversion to SN-38 (P = .26). CONCLUSION: BSA is not a predictor of CPT-11 clearance or SN-38 pharmacokinetics and does not contribute to reducing kinetic variability. These findings provide a rationale for the conduct of a comparative phase III study between BSA-based dosing and flat or fixed dosing of CPT-11.
Relationship of Dental and Oral Pathology to Systemic Illness
Authors: Harold C. Slavkin
Journal: JAMA (2000)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal
N-Terminal B-Type Natriuretic Peptide Assessment Provides Incremental Prognostic Information in Patients With Acute Coronary Syndromes and Normal Troponin T Values Upon Admission
Authors: Michael Weber, Oscar Bazzino, Jose L. Navarro Estrada, Juan J. Fuselli, Fernando Botto, Diego Perez de Arenaza, Helge Möllmann, Holger N. Nef, Albrecht Elsässer, Christian W. Hamm
Journal: Journal of the American College of Cardiology (2008)