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Biomedical subjects

M Casey

Publications and source records attributed to M Casey.

At least 55 records · Page 3Linked to original sources
PubMed1998

Serving rural Medicare risk enrollees: HMOs' decisions, experiences, and future plans.

This article identifies factors that influence health maintenance organizations' (HMOs) decisions about offering a Medicare risk product in rural areas; describes HMOs' recent experiences serving rural Medicare risk enrollees; and assesses the potential impact of Medicare program changes on the future willingness of HMOs to offer a Medicare risk product in rural areas. Data for the analysis were collected through interviews with a national sample of 27 HMOs. The results underscore the importance of adjusted average per capita cost (AAPCC) rates in HMOs' decisions to offer Medicare risk products in rural areas, but also indicate that other factors influence these decisions.

Aged↗
PubMed1997

Mastectomy without malignancy after carcinoma diagnosed by large-core stereotactic breast biopsy.

Mammary carcinoma diagnosed by large-core stereotactic biopsy (LCSBB) is often followed by definitive surgery. We report on positive (malignant) LCSBB followed by definitive surgery that failed to demonstrate malignancy. Between January 1993 and August 1996, 206 women in our institution underwent LCSBB. Carcinoma was diagnosed in 45 patients (22%) of the 206 (ductal carcinoma in situ (DCIS), n = 12; invasive carcinoma, n = 33). Twenty-nine of the 45 patients subsequently underwent mastectomy, and 8 of 45 underwent lumpectomy. In 34 (92%) of these 37 patients, carcinoma was demonstrated at follow-up surgery, but in 3 patients (8%), mastectomy failed to reveal carcinoma. The characteristics of these three patients are as follows: Patient 1 was a 58-year-old woman with a nonpalpable 6- to 8-mm nodule revealed by a screening mammogram. Three of 8 LCSBBs showed colloid carcinoma, but histologic examination of 50 paraffin blocks and radiographic examination of the mastectomy sample failed to reveal carcinoma. Patient 2 was a 64-year-old woman with a nonpalpable 6- to 9-mm nodule revealed by mammogram. Six of 12 LCSBBs showed tubular carcinoma, but histologic examination of 30 paraffin blocks from her mastectomy sample failed to reveal carcinoma. Patient 3 was a 72-year-old woman with a history of DCIS. She had undergone a lumpectomy and radiotherapy, and she had suspicious ipsilateral microcalcifications. Two of 8 LCSBBs showed comedo DCIS, but histologic examination of 26 paraffin blocks and radiographic examination of the mastectomy sample failed to reveal carcinoma. Possible explanations for a mastectomy without malignancy after carcinoma was diagnosed by LCSBB include removal of the entire lesion by LCSBB, inflammatory response obliterating remaining tumor, false-positive core biopsy result, patient misidentification, inadequate sampling of the surgical specimen, and failure to remove the tumor. We outline a series of steps for the pathologists to follow when confronted with such a case.

Adenocarcinoma↗
PubMed1996

The dynamics of discrete-time computation, with application to recurrent neural networks and finite state machine extraction.

Recurrent neural networks (RNNs) can learn to perform finite state computations. It is shown that an RNN performing a finite state computation must organize its state space to mimic the states in the minimal deterministic finite state machine that can perform that computation, and a precise description of the attractor structure of such systems is given. This knowledge effectively predicts activation space dynamics, which allows one to understand RNN computation dynamics in spite of complexity in activation dynamics. This theory provides a theoretical framework for understanding finite state machine (FSM) extraction techniques and can be used to improve training methods for RNNs performing FSM computations. This provides an example of a successful approach to understanding a general class of complex systems that has not been explicitly designed, e.g., systems that have evolved or learned their internal structure.

Neural Networks, Computer↗
PubMed1996

Risks of radiation exposure to orthopaedic surgeons.

The risks of occupational radiation exposure for orthopaedic surgeons has not been well documented. The use of fluoroscopy in orthopaedics has reduced morbidity and by reducing operative time and by reducing the invasiveness of procedures. Increasingly procedures requiring the use of fluoroscopy are being developed. In a prospective study we have monitored cumulative radiation exposure over a 6-month period. The exposure levels are well below the maximum dose limits for ionizing radiation as recommended by European Economic Communities EURATOM directives. Experimentally using a phantom patient it was shown that the exposure to ionizing radiation during the insertion of a dynamic hip screw was minimal. Despite the low level of exposure care should be exercised when using fluoroscopy.

Film Dosimetry↗
PubMed1995

Availability of rural Minnesota obstetric services: is it a problem?

In the late 1980s several published articles predicted a crisis in the availability of obstetric care due to declining numbers of rural obstetrical providers. Several state and national studies documented the adverse impact of malpractice and time demands on both urban and rural physicians. But only limited information is available to document current trends in rural obstetrical practice and assess whether or not the predicted crisis occurred. This study sought to provide that updated information for rural Minnesota. A telephone survey of all rural Minnesota obstetrical providers was used to document the number, location, and specialty of rural obstetrical providers, their practice limitations, and plans for future practice. This data was combined with state perinatal statistics for each county to further assess obstetrical care availability and perinatal outcomes. All rural Minnesota obstetricians and certified nurse midwives provide obstetrical care as did 69 percent of all rural family physicians. Only 27 percent of rural obstetrical providers put any type of restrictions on their obstetrical practices. During the past year, 67 currently practicing rural physicians have stopped providing obstetrical care while 55 new obstetrical providers have begun rural practice. Two to 3 percent of current rural providers plan to retire or discontinue obstetrical services during the next five years. The provider demographics from the survey identified eight counties with no prenatal providers, and 12 additional communities of decreased provider availability. However, only two of the counties with no prenatal providers and five of the counties with areas of limited providers had increased percentages of adverse prenatal outcomes such as low birthweight or late prenatal care. This study concluded that Minnesota does not have a serious statewide problem with availability of rural obstetrical providers. However, a few isolated regions of the state have limited provider availability, including limited availability of local high-risk services and consultants.

Catchment Area, Health↗
PubMed1995

Nursing diagnosis: language antithetical to nursing's ontology.

The term nursing diagnosis is constructed in male, medical language. As such, it is proposed that it has no legitimacy in nursing discourse as it is antithetical to notions claimed foremost in nursing's ontology. It is also posited that the term 'nursing diagnosis', whilst reinforcing biomedicine, has little or no meaning to many nurses, is not understood by patients and has no justifiable place in health care discourse.

Empathy↗
PubMed1994

The in-training examination in internal medicine.

OBJECTIVE: The In-Training Examination in Internal Medicine (ITE-IM) has been offered to internal medicine trainees annually since 1988 as an instrument for self-assessment. This report outlines the manner in which the test is prepared, reviews the results of annual examinations, and analyzes trends during the past 6 years. DESIGN: Results of each examination were reviewed with regard to the demographic characteristics of persons taking the test, their previous medical training, and their present program affiliations. RESULTS: Then number of residents participating in the ITE-IM has increased steadily over the past 6 years. In 1993, more than 12,000 residents from more than 90% of internal medicine training programs in the United States participated in the examination; the percentage of international medical school graduates taking the examination increased from 27% in 1988 to 47% in 1993. Statistical analyses of each examination have shown it to be reliable, internally consistent, and discriminating. Over the past 6 years, graduates of U.S. medical schools have scored consistently higher than those of international medical schools and schools of osteopathic medicine on all annual examinations. However, in 1993, for residents at all levels of training, the differences in scores between graduates of U.S. medical schools and graduates of international medical schools narrowed substantially. From 1988 to 1993, there has been a trend toward lower scores by every cohort on each subsequent examination. The decreases in scores are most pronounced for graduates of U.S. medical school and those of schools of osteopathic medicine. The lower scores may be caused by either an increased level of difficulty in the examination or decreased knowledge among examinees. CONCLUSIONS: The ITE-IM is a useful instrument to assess the knowledge base of residents and program directors with a reliable evaluation of themselves and their programs in comparison to their national peer groups. It also provides objective data to monitor trends over time in residents' scores and relates them to the changing demographic characteristics of trainees and to innovations in the clinical curricula of internal medicine training programs.

Clinical Competence↗
PubMed1994

Phosphorylation of the Drosophila adherens junction protein Armadillo: roles for wingless signal and zeste-white 3 kinase.

The Drosophila segment polarity gene product Armadillo provides a link between two seemingly separate processes, regulation of segmental pattern by the Wingless intercellular signal and the function of cell-cell adherens junctions. armadillo was originally identified because of its segment polarity phenotype but subsequently was found to be the homolog of the vertebrate adherens junction protein beta-catenin. We examined the nature of the post-translational modification of Armadillo and its possible role in regulating Armadillo function. Armadillo is a phosphoprotein. Its level of phosphorylation varies both during embryonic development and from tissue to tissue. Phosphorylation occurs on both serine or threonine and tyrosine residues. Finally, Wingless signal negatively regulates Armadillo phosphorylation, while the segment polarity gene product Zeste-white 3, a serine/threonine protein kinase, promotes Armadillo phosphorylation. We discuss the implications of these results for regulation of Wingless/Wnt-1 signaling and adherens junction function.

Amino Acid Sequence↗
PubMed1994

wingless signal and Zeste-white 3 kinase trigger opposing changes in the intracellular distribution of Armadillo.

wingless/wnt-1 signaling directs cell fate during development. Genetic analysis in Drosophila identified genes that may encode components of the wingless signal transduction system. Drosophila Armadillo, homolog of vertebrate beta-catenin, is required for wingless signaling. Unlike armadillo RNA, Armadillo protein accumulates non-uniformly in different cells of each embryonic segment. We found that cells alter their intracellular distribution of Armadillo in response to Wingless signal, accumulating increased levels of cytoplasmic Armadillo relative to those of membrane-associated protein. Levels of cytoplasmic Armadillo are also regulated by Zeste-White 3 kinase. Analysis of double mutants demonstrates that Armadillo's role in wingless signaling is direct, and that Armadillo functions downstream of both wingless and zeste-white 3. We present a model for the role of Armadillo stripes in transduction of wingless signal.

Animals↗
PubMed1994

Technical note: room shielding requirements in diagnostic radiology.

New regulations propose a more stringent limit to the radiation exposure of workers and members of the public. The shielding in X-ray areas will have to be reassessed to take account of these new limits. This technical note identifies a computerized technique for evaluating shielding requirements which yields results that are significantly more cost effective than those determined by traditional methods.

Facility Design and Construction↗
PubMed1994

Health assessment and the nursing process: a means to an end?

The content and process of teaching health assessment coupled with the nursing process gathers momentum because it is consistent with health policy based on the principles of economic rationalism, and it covertly perpetuates positivist medical discourse while overtly postulating the emancipatory nature of adopting such practices.

Holistic Health↗
PubMed1993

Clinical disease associated with Trypanosoma theileri infection in a calf in Ireland.

A four-month-old calf had a clinical history of pyrexia, anaemia, weight loss and behavioural abnormality. Clinical examination revealed evidence of regenerative anaemia and a lymphocytosis which was characterised by a relatively large B cell population. The calf deteriorated clinically while under observation and its prescapular and prefemoral lymph nodes became enlarged. Examination of a blood smear revealed the presence of a large number of circulating Trypanasoma theileri. Serological examination showed the presence of the invariant, stage-specific, trypanosome surface antigen, ISG70 and antibodies against ISG70. ISG70 was first identified in the bloodstream forms of Trypanosoma brucei and has not previously been found in T theileri. Clinical recovery was associated with an increase in packed cell volume, a decrease in the levels of circulating anti-ISG70 antibodies and the complete disappearance of circulating ISG70.

Animals↗
PubMed1993

Intestinal bile acid malabsorption in cystic fibrosis.

This study aimed at examining the mechanisms participating in excessive faecal bile acid loss in cystic fibrosis. The study was designed to define the relation between faecal fat and faecal bile acid loss in patients with and without cystic fibrosis related liver disease; to assess terminal ileal bile acid absorption by a seven day whole body retention of selenium labelled homotaurocholic acid (SeHCAT); and to determine if small intestinal bacterial overgrowth contributes to faecal bile acid loss. The study population comprised 40 patients (27 men; median age 18 years) with cystic fibrosis (n = 8) and without (n = 32) liver disease and eight control subjects. Faecal bile acid excretion was significantly higher in cystic fibrosis patients without liver disease compared with control subjects (mean (SEM) 21.5 (2.4) and 7.3 (1.2) micromoles/kg/24 hours respectively; p < 0.01) and patients with liver disease (7.9 (1.3) micromoles/kg/24 hours; p < 0.01). No correlation was found between faecal fat (g fat/24 hours) and faecal bile acid (micromoles 24 hours) excretion. Eight (33%) of cystic fibrosis patients had seven day SeHCAT retention < 10% (normal retention > 20%). SeHCAT retention in cystic fibrosis patients with liver disease was comparable with control subjects (30.0 (SEM) 8.3% v 36.8 (5.9)%; p = NS) while SeHCAT retention in cystic fibrosis patients who did not have liver disease was significantly reduced (19.9 (3.8); p < 0.05). Although evidence of small bowel bacterial overgrowth was present in 40% of patients no relation was found between breath hydrogen excretion, faecal fat, and faecal bile acid loss. The results are consistent with the presence of an abnormality in terminal ideal function in patients with cystic fibrosis who do not have liver disease and that a defect in the ileal absorption of bile acids may be a contributory factor to excessive faecal bile acid loss. Faecal bile acid loss in cystic fibrosis is unrelated to the presence of intraluminal fat or intestinal bacterial overgrowth.

Adolescent↗
PubMed1993

Exercise-related potassium and free fatty acid level changes in coronary artery disease. Responses after moderate intensity training.

Exercise produces changes in circulating levels of potassium and free fatty acids which may provoke arrhythmias in patients with coronary artery disease. Twenty patients participating in 6 weeks of training were studied; 9 of these patients took part in 4 more weeks of training and a third exercise test. After 6 weeks, potassium levels were higher at submaximal levels of exercise, free fatty acid levels were reduced at rest, and at 5, 15, and at 30 min post-exercise. Norepinephrine levels were reduced at submaximal work loads after 6 weeks and increased at maximal work loads. The extra 4 weeks had no additive effect on these metabolic changes. Participation by coronary artery disease patients in a short-term, moderate intensity, exercise training program increases potassium levels at submaximal work loads and reduces levels of free fatty acids at rest and after exercise. The arrhythmogenic relevance of these findings deserves further consideration.

Aged↗
PubMed1992

Biliary complications of cystic fibrosis.

One hundred and four adult patients with cystic fibrosis were evaluated for the presence of liver disease as defined by abnormal liver function tests of six months' duration, histological evidence of fibrosis or cirrhosis, or the presence of portal hypertension, or both. Twenty patients fulfilled these criteria and were evaluated further for the presence of biliary tract abnormalities with biliary scintigraphy using 99Tc diisopropylphenyl-carboxymethyl iminodiacetic acid (DISIDA) and endoscopic retrograde cholangiography. Clearance of 99Tc DISIDA from the liver and biliary tree was diminished at 45 (E45) and 60 (E60) minutes in the patients with liver disease compared with those without liver disease; E45 = 37.8% and 65.8%, p less than 0.01; E60 = 48.2% and 77.5%, p less than 0.01 respectively. Serial analogue images of the extrahepatic biliary tree were consistent with common bile duct obstruction with retention of DISIDA and tapering of the common bile duct in seven of 18 patients with and two of 10 patients without liver disease. Endoscopic retrograde cholangiography showed changes consistent with sclerosing cholangitis, with beading and stricturing of the intrahepatic ducts in 12 of the 14 patients. In all 14 patients, including those in whom biliary scintigraphy had suggested obstruction, no abnormality of the common bile duct was identified. These results indicate that abnormalities of the bile ducts in patients with cystic fibrosis related liver disease are confined to the intrahepatic biliary tree and that common bile duct strictures do not contribute to either the progression or development of liver disease in these patients.

Adolescent↗