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At least 1,297 records · Page 72Linked to original sources
PubMed2004

Three-dimensional comparison of interventional MR radiofrequency ablation images with tissue response.

OBJECTIVE: Solid tumors are being treated using radiofrequency (RF) ablation under interventional magnetic resonance imaging (MRI) guidance. We are investigating the ability of MRI to monitor ablation treatments by comparing MR images of thermal lesions to histologically assayed tissue damage. MATERIAL AND METHODS: An open MRI system was used to guide an ablation electrode into five rabbit thigh muscles and acquire post-ablation MR image volumes. We developed a methodology using a 3D computer registration to make spatial correlations. After MR and histology images were registered with an accuracy of 1.32+/-0.39 mm (mean+/-SD), a boundary of necrosis identified in the histology was compared with the outer boundary of the hyperintense region in MR images. RESULTS: For 14 T2-weighted MR images, the absolute distance between boundaries was 0.96+/-0.34 mm (mean+/-SD). Since the small discrepancy between boundaries is comparable to our registration accuracy, the boundaries may match exactly. Similar correlations to histology were obtained with a deformable model segmentation method. CONCLUSIONS: This is good evidence that MR thermal lesion images can be used during RF ablation treatments to accurately localize the zone of necrosis at the lesion margin.

Animals↗
PubMed1981

Medicare program; schedule of limits on hospital per diem inpatient general routine operating cost for cost reporting periods beginning on or after July 1, 1981: Health Care Financing Administration.

This notice sets forth a schedule of limits on hospital per diem impatient general routine operating costs that may be reimbursed under Medicare for cost reporting periods beginning on or after July 1, 1981. This is an annual update of the schedule, and will replace the current schedule, which was published in the Federal Register on June 20, 1980 (45 FR 41868). This schedule does not apply to the costs of special care units or ancillary services, to capital-related costs or costs of malpractice insurance, or to the costs a hospital allocates to the interns and residents (in approved programs) or nursing school cost centers on its Medicare cost report. The notice explains the methodology we used to compute the revised schedule of limits.

Cost Allocation↗
PubMed2001

Structure-specificity relationships for haloalkane dehalogenases.

A structural analysis of the substrate specificity of hydrolytic dehalogenases originating from three different bacterial isolates has been performed using the multiple computer-automated structure evaluation methodology. This methodology identifies structural fragments in substrate molecules that either activate or deactivate biological processes. The analysis presented in this contribution is based on newly measured dehalogenation data combined with data from the literature (91 substrates). The enzymes under study represent different specificity classes of haloalkane dehalogenases (haloalkane dehalogenase from Xanthobacter autotrophicus GJ10, Rhodococcus erythropolis Y2, and Sphingomonas paucimobilis UT26). Three sets of structural rules have been identified to explain their substrate specificity and to predict activity for untested substrates. Predictions of activity and inactivity based on the structural rules from this analysis were provided for those compounds that were not yet tested experimentally. Predictions were also made for the compounds with available experimental data not used for the model construction (i.e., the external validation set). Correct predictions were obtained for 28 of 30 compounds in the validation set. Incorrect predictions were noted for two substrates outside the chemical domain of the set of compounds for which the structural rules were generated. A mechanistic interpretation of the structural rules generated provided a fundamental understanding of the structure-specificity relationships for the family of haloalkane dehalogenases.

Biodegradation, Environmental↗
PubMed2001

[The development and application of computer-aided bone histomorphometry system].

The aim of this study is to develop a Computer-aided Bone Histomorphometry System. The method is based on the Micro-graphical Digital System composed of microscope, digital camera, computer and related programs. The methodology was developed to measure the basic data on each image of visual field of hard bone tissue with computer-assistance. Following this, the parameters of bone volume, bone structure and bone metabolism were calculated based on the standardization of bone histomorphometry. Such method has been used in the experimental and clinical studies of osteoporosis to predict the fracture risk and evaluate the drug effect.

Bone Density↗
PubMedDate not supplied

Health-related cost-to-benefit measurement. A difficult sell in a "show me the money" era.

"Cost to benefit" is both a generic term and a specific technique used to describe and guide budgetary and investment scenarios. The methodology is based on computer mathematical models to prospectively define the short- and long-term financial gain or burden that may be produced by investing today's dollars in tomorrow's programs, technology or facilities.

Cost-Benefit Analysis↗
PubMedDate not supplied

Clinical features of second other-site primary cancers among sporadic colorectal cancer patients--a hospital-based study of 3,722 cases.

BACKGROUND/AIMS: Although synchronous and metachronous colorectal cancers are now well known to all colorectal surgeons, second other-site primary cancers following colorectal cancer are unfamiliar to most colorectal physicians. Knowledge of the clinical characteristics of these second other-site primary cancers becomes important especially during their follow-up surveillance. METHODOLOGY: Information from a computer database was retrieved. Medical records were reviewed and all histopathological data were confirmed. RESULTS: Forty-seven (1.26%) patients developed second other-site primary cancers. Of these patients, 22 (46.8%) patients were diagnosed concordantly while 25 (53.2%) patients were discordant cases. Twelve of 25 (45%) discordant cases were found within one year postoperatively. Regarding the clinical features of these 47 patients, male patients more frequently develop discordant cases (p=0.031). A significantly higher proportion of Dukes' B patients developed second other-site primary cancer than that of patients of other stages (p=0.017). Liver, 8 (17%) cases, was the most common site followed by the prostate, 6 (13%), stomach, 6 (13%), lung, 5 (11%), head and neck cancers, 5 (11%), and kidney, 3 (6.4%). However, there was not a significantly increased risk for these sporadic colorectal patients statistically. CONCLUSIONS: We described clinical features of second other-site primary cancers and emphasized that knowledge of these is important for their postoperative surveillance.

Colectomy↗
PubMedDate not supplied

Medical education - changing perspectives.

Various aspects of medical education have been reviewed with special reference to medical institutions in Nepal. The newer trends in teaching methodology like audiovisual and computer aided methods are being followed in most of the institutions of Nepal. Similarly, attempts are being made to implement integrated teaching which, though not perfect, differs from institution to institution. The attempts seem to be more or less satisfactory with awareness amongst most of the teachers and planners. However, the methods of assessment of the students at every level, call for changes and improvement, in the light of modern trends. Similarly, the process of selection in medical colleges needs change. The replies to the questionnaire given to the students of two batches were very interesting and it is worthwhile to undertake such studies in other institutions as well. Valid suggestions opined by them should be implemented.

Curriculum↗
PubMedDate not supplied

Comparison of radiological and histological findings in autoimmune pancreatitis.

BACKGROUND/AIMS: Autoimmune pancreatitis displays radiological findings that are sometimes difficult to differentiate from pancreatic carcinoma. To understand the essential radiological features of autoimmune pancreatitis (AIP), we compared imaging and histological findings in resected AIP specimens. METHODOLOGY: Findings of ultrasonography, computed tomography, endoscopic retrograde cholangiopancreatography and angiography were examined retrospectively for 6 patients who underwent pancreatoduodenectomy on suspicion of pancreatic carcinoma, and compared with histological findings of the resected specimens. RESULTS: Ultrasonography showed an enlarged hypoechoic pancreas with sausage-like appearance and no lobulation in the contour of the pancreas. On computed tomography imaging, delayed enhancement of the swollen pancreatic parenchyma became evident. Dense lymphoplasmacytic infiltration with fibrosis involving peripancreatic tissue was observed throughout almost the entire pancreas. Periductal non-occlusive fibrosis with lymphoplasmacytic infiltration induced narrowing of the pancreatic duct. Stenosis of the common bile duct is frequently associated with autoimmune pancreatitis and is induced by diffuse thickening of the duct wall by the same inflammatory process as that of the pancreas. The fibroinflammatory process also involves blood vessels. CONCLUSIONS: Characteristic radiological findings of autoimmune pancreatitis are induced with systemic histological changes of lymphoplasmacytic infiltration with fibrosis, and differ from schirrous invasion of pancreatic carcinoma.

Aged↗
PubMedDate not supplied

[Methodology of supplying the work place of medical workers with computers].

The new approach to the construction of the problem-orientated automated working places of the main-modular structure, suggested by the authors, solves not only the concrete problems of the clinical subdivision in collecting, storing and processing information but can also be the basis of the information system of a health care facility as a whole (e.g. diagnostic centers of various purpose, specialized clinics and outpatient polyclinics).

Electronic Data Processing↗
PubMed1983

Research needs and priorities for ruminant internal parasites in the United States.

The management-chemotherapy approach is currently the most applicable means of effectively and practically controlling parasites of ruminants. Knowledge of regional patterns for major ruminant parasites, especially seasonal transmission dynamics, promises to lead to major improvements in management-chemotherapy systems. This knowledge also provides the fundamental context for design of new integrated control strategies that include other approaches such as immunization, chemical and biological control, and the interaction of environmental, physiologic, and nutritional factors. Greatly needed is a change in the protracted government regulatory process that obviates the availability of new, more effective drugs until years after they are available in other developed nations and that creates a dearth of "minor species, minor use" antiparasitic compounds. It is necessary to recognize both the need for product safety and the realities of investment limitations in the pharmaceutical industry. Also needed are new formulations and better methods of mass treatment for inaccessible herds of ruminants that will allow flexibility in strategic treatment programs based on seasonal transmission and other factors. More reliable cost-benefit assessments, more sensitive diagnostic indicators, and better knowledge of pathophysiologic mechanisms of damage by parasites will assist greatly in identifying the economically important effects against which economical control programs can be targeted. The opportunities for development and evaluation of novel prophylactic, diagnostic, and management approaches for animal parasitism are close at hand if the spectacular advances in molecular biology, immunology, computer science, and ecologic methodologies are assimilated in present research efforts. Although the emphasis of this report is on applied research and identification of approaches for the immediate future, the importance of more basic research on animal parasites and discoveries in other areas of modern biology and medicine are recognized as the essential pacesetters of the future. There is increasing concern by agricultural research workers that renewal of this base of fundamental knowledge is greatly needed. In this context, studies on the physiology, behavior, antigenicity, and genetic makeup of parasites, protective host responses, and mechanisms of tissue destruction and invasion by veterinary parasites are essential. Veterinary parasitologists must study host-parasite interactions directly with minimal reliance on rodent model systems; although this has disadvantages it offers special opportunities for research that is concurrently applied and fundamental. While the livestock industry can expect continuous progress on current problems, a long-term investment in basic research must be made for the future.

Animals↗
PubMed1997

A logistic-bivariate normal model for overdispersed two-state Markov processes.

We describe a logistic-bivariate normal mixture model for a two-state Markov chain in which each individual makes transitions between states according to a subject-specific transition probability matrix. The use of the bivariate normal mixing distribution facilitates inferences regarding the correlation of the random effects and hence provides insight as to the nature of the subject-to-subject variability in the transition probabilities. Tests regarding the correlation can be based on likelihood ratio, score, or Wald statistics. Estimates of the transition intensities of a latent continuous time conditionally Markov process may also be computed. We illustrate this methodology by application to a parasitic infection field study and contrast our findings with those previously published on this data set.

Biometry↗
PubMed1976

An approach to the analysis of menstrual patterns in the critical evaluation of contraceptives.

An approach to a standardized analysis of menstrual bleeding patterns is presented. The method utilizes a prospective bleeding record and characterizes the menstrual pattern of a woman according to bleeding and nonbleeding events without imposing definitions of cycle or intermenstrual bleeding. Further, the analysis is done within a time reference period similar to life-table analysis, with the experience of each woman having equal value. The method is thus applicable to the study of menstrual patterns of both normal, untreated women, and women on experimental contraceptive regimens in which expected bleeding patterns are disrupted. The methodology is aided by computer programs to process the data and by the use of standard statistical packages for comparison of output data of different groups.

Computers↗
PubMed1997

[Effects of bisphosphonates on the mechanical efficiency of normal and osteopenic bones].

Bone mechanical competence (stiffness, strength) at organ level is determined by mechanical quality (intrinsic stiffness) and spatial distribution (macro-architecture) of bone material in cortical tissue (in every bone) and trabecular network (in vertebral bodies). These properties are inter-related and controlled according to mechanical usage by a feed-back mechanism known as mechanostat. Therefore, the effects on bone fragility of any treatment should be evaluated concerning the way they may have affected bone material or geometric properties as well as the mechanostatical interactions between them. Standard densitometry does not provide the necessary data, but some alternative methodologies (as peripheral quantitative computed tomography, pQCT) are being developed to complement or even substitute SPA, DPA or DXA determinations. Bisphosphonate (BP) effects on bone biomechanics have been studied only in animal models. Many sources of variation of results (type of compound, dose, mode of administration, species, race, sex, age, age since menopause, type of bone, remodeling ability of the skeleton, endocrine-metabolic status, interactions with other treatments, etc.) have been reported. In general terms, BPs are beneficial concerning cortical bone strength in purely modeling species (rodents) and trabecular strength in remodeling mammals (dogs, baboons). This positive action at organ level depends on independent improvements in bone macro-architecture (mainly affected by bone modeling) and material stiffness (chiefly affected by bone composition and remodeling). On one hand, bone macro-architecture has been positively affected by BPs in normal (not in ovariectomy (OX), steroid- or disuse-induced osteopenic) animals. On the other, bone material quality has been improved in the latter but not in the former. Mechanostatic interrelationships have been differently affected according to the compound employed. Results reported by ours and other laboratories concerning the three derivatives available nowadays in Argentina were reviewed and summarized. Pamidronate improved small rodents' cortical bone strength and geometric properties at low doses but impaired mineralization, material properties and strength at toxic doses. In normal, remodeling animals it improved mechanical properties in vertebral bodies but not in long bones. It also prevented the negative impact of OX-, steroid- or disuse-induced osteopenia in rats by improving bone material properties without affecting normal mechanostatic interrelationships. Olpadronate exerted positive effects on long-bone strength at any dose in normal rats and mice by improving cross-sectional properties and preserving both mineralization and material properties. These effects were highly dependent upon bone deformability, body weight, and mechanical usage of the limb as an evidence of an anabolic interaction induced on bone modeling and mechanostatic interrelationships. This compound also prevented the OX- or disuse-induced impairment in rat cortical long-bone strength and recovered rat cortical bone when given since 3 months after OX by improving only bone material quality. No interaction with bone mechanostat was detected in these studies. Alendronate effects on bone biomechanics in normal rats and dogs were positive only in long treatments. They were highly dependent on body weight of the animals, hence a positive interaction with bone mechanostat should be hypothesized. It also prevented the negative impact of OX in rat femurs by improving cortical material quality with no effect on cross-sectional properties, i.e., exerting an anti-catabolic interaction with bone mechanostat. The effects of all the three compounds were found positive for bone health, yet their mechanisms of action varied with type of bone and subject condition. A striking dissociation between (positive) effects on bone strength and (variable) effects on bone stiffness was repeatedly observed in these studies. Also an enla

Animals↗
PubMed1998

Bombing and psychopathy: an integrative review.

A review of the research on the motivations and behaviors of bombers is presented. The methodology consisted of a computer search of eight databases, book reviews, and telephonic interviews with local and federal law enforcement. The data were then compared to the substantial research on psychopathy. The authors conclude that a federally funded research effort is necessary, and should incorporate various structured interviews, history gathering, and psychological and physiological tests of incarcerated bombers, theoretically guided by the concordance between the known motivations and behavior of bombers and the concurrent and predictive validity of the construct, psychopathy.

Criminal Psychology↗
PubMed1998

Guideline generation from data by induction of decision tables using a Bayesian network framework.

Decision tables can be used to represent practice guidelines effectively. In this study we adopt the powerful probabilistic framework of Bayesian Networks (BN) for the induction of decision tables. We discuss the simplest BN model, the Naive Bayes and extend it to the Two-Stage Naive Bayes. We show that reversal of edges in Naive Bayes and Two-stage Naive Bayes results in simple decision table and hierarchical decision table respectively. We induce these graphical models for dementia severity staging using the Clinical Dementia Rating Scale (CDRS) database from the University of California, Irvine, Alzheimer's Disease Research Center. These induced models capture the two-stage methodology clinicians use in computing the global CDR score by first computing the six category scores of memory, orientation, judgment and problem solving, community affairs, home and hobbies and personal care, and then the global CDRS. The induced Two-Stage models also attain a clinically acceptable performance when compared to domain experts and could serve as useful guidelines for dementia severity staging.

Algorithms↗
PubMed2001

[Ongoing health management control by cost monitoring through tracer indicators].

OBJECTIVE: To determine the operational cost of a hospital's surgical unit, compare those results with standards, and determine the incidence of the costs; to produce an effective methodology for this purpose that can be applied to all kinds of medical units using any low-cost widely available computer database system, with that methodology being utilized for ongoing management control. METHODS: This study was carried out in 1999 in the Orthopedics and Traumatology Unit of the "Domingo Funes" Public Hospital, in the province of Córdoba, Argentina. Of the 817 patients who underwent diagnostic or therapeutic procedures in that unit during the year, we selected the 154 of them who were hospitalized and required surgical or instrumental procedures. The study used the tracer event method described by Kessner. Through a consensus process, medical specialists and health economists selected and defined these indicators, which were categorized in relation to their complexity (high, medium, limited, or none). Direct and indirect costs were assessed in order to study their contribution to total cost. Total cost was estimated using nine variables that were applied to the different tracer events. RESULTS: The largest portion of total cost, both real and standard, was based on the "bed-day" variable. Of this bed-day cost for all tracer events, 51.2% was due to an indirect cost of "social hospitalization" (keeping patients hospitalized for such reasons as transportation difficulties or delays in receiving requested medical supplies) and 48.8% to a direct cost of true therapeutic hospitalization. This bed-day cost was 117% higher for the real costs as compared to the standard costs. The indirect costs of social hospitalization and of therapeutic supplies made up nearly half of the total real cost. Excluding the indirect costs, the real cost of all the tracer events exceeded the standard cost by only 6.4%. Including the indirect costs of social hospitalization and of therapeutic supplies, the real cost exceeded the standard cost by 39.8%. The amount spent on medical staff and support personnel represented just 11.5% of the total cost. DISCUSSION: Suggestions are provided in various areas, including solutions for the high cost of social hospitalization and therapeutic supplies, the cost-control benefits of creating protocols for procedures and treatments, and the rational utilization of technology in order to improve efficiency and reduce risks. The wider application of this procedure is recommended for cost-management control in all hospital units carrying out surgery or other medical procedures.

Argentina↗