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Biomedical subjects

R Rada

Publications and source records attributed to R Rada.

At least 19 recordsLinked to original sources
PubMed2006

Bioabsorbable staple-line reinforcement to reduce staple-line bleeding in the transection of mesenteric vessels during laparoscopic colorectal resection: a pilot study.

BACKGROUND: Staple line hemorrhage and leak are the 2 most dreaded complications of laparoscopyassisted resection of colorectal cancer (LARCC). Recently, anastomotic staple lines have been reinforced with a range of absorbable and non-absorbable bioprosthetic reinforcement materials. This pilot prospective study used the bioabsorbable Seamguard (BSG; WL Gore & Associates, Flagstaff, AZ) for routine reinforcement of the mesenteric vascular staple transection to prevent mesenteric hemorrhage and to assess its safety and feasibility in a consecutive series of laparoscopic colonic resections. METHODS: Twenty-five patients consecutively scheduled to undergo LARCC were enrolled in the study. All operations were performed with a standard LARCC technique which included loading of the BSG sleeves onto the jaws of the cutter/stapler. RESULTS: There were 23 wholly LARCC cases and 2 open conversions. BSG was used in all 25 patients. No patient experienced staple-line bleeding or other complications during the surgical procedure. The mean number of staple-line reinforcement sleeves used was 2.6 (range, 2-4). The mean operative time was 118 minutes (range, 65-184 minutes). Additional measures to achieve hemostasis were not required in any case. The mean cost was US 475.20 dollars for the procedure. CONCLUSIONS: This small pilot study has shown the routine use of BSG mesenteric staple line reinforcement to be safe, quick and effective during LARCC.

Absorbable Implants↗
PubMed2006

Use of anorectal ultrasounds in perianal Crohn's disease: consistency with clinical data.

BACKGROUND: anorectal ultrasonography (ARU) is a simple technique, and its diagnostic value for anorectal diseases either in conventional subjects or in patients with Crohn s disease (CD) is insufficiently reported. The objective of this study is to evaluate the use of ARU, its consistency with clinical orientation, and its ability to provide relevant information for patients with bowel CD and perianal involvement. METHODS: thirty ARUs were performed for 24 patients (17 male, mean age 35,7 years; range 19-59 years) with diagnosed CD (bowel and anorectal involvement). The reason to perform an ARU was to evaluate an anal fistula (15 patients, 50%), potential abscesses (9 patients, 30%), and fecal incontinence (2 patients, 6,6%), and for post-treatment monitoring purposes (4 patients, 13,3%). RESULTS: diagnostic orientation coincided for 14 patients (46,6%). An abscess was found in eight patients (26,6%), and five patients were clinically suspicious. The abscess was postanal in 3 patients. Fistulas were found in 17 patients (56,6%), and 15 patients were clinically suspicious. Transsphincterian fistulas were observed in seven patients, and abscesses were associated with fistula in six patients. Transsphincteric defects were observed in 10 patients (four internal sphincters, one external sphincter, and five both) but only two patients suffered from incontinence. ARU provided data relevant to therapeutic approach in 19 patients (63,3%). CONCLUSIONS: ARU has provided very important data for the diagnosis and treatment of anorectal diseases. Based on this technique clinical decisions can be improved, which in some instances may prove critical.

Abscess↗
PubMed2001

[Prevalence of migraine among primary- and secondary-school students in Mérida, Venezuela].

OBJECTIVE: The epidemiological impact of headaches in populations is not adequately known since most of the data come from clinical studies. Therefore, we decided to survey a population of students in the municipality of Libertador, in the state of Mérida, Venezuela, to determine the prevalence of migraines, the incapacitating effect of headaches in general, and the proportion of individuals who self-medicate. METHODS: We first used stratified sampling to choose schools in the municipality, and then simple random sampling to select which classrooms to survey. A total of 1,714 students, ranging in age from 10 to 21 years old, completed a survey. RESULTS: Among the students, 84.4% of them reported having had headaches, and 16.8% of them reported experiencing migraines. We did not find a noticeable incapacitating effect of migraines in this population. Of the students who had had headaches, 69.2% of them did not request medical care, and 80.3% of them reported self-medicating. CONCLUSIONS: From these results we conclude that migraines are very frequent among this population. Judging from the levels of self-medication and the lack of medical attention for headaches, we believe there is a shortfall in health services coverage and a deficiency in public information, which together lead to an underreporting of headaches.

Adolescent↗
PubMed1997

Improving outpatient clinic efficiency using computer simulation.

To assess and plan alterations in outpatient clinic structure, produces a computer simulation of an outpatient clinic based on detailed time and role measurements from the authors' clinic. The stimulation which used an object-oriented design method is able to indicate the impact of changes in clinic structure using patient and doctor waiting times in clinic as endpoint measures. The effects of changes in clinic size, consultation time, patient mix, appointment scheduling and non-attendance were examined. We found that patient waiting time could be shortened considerably by using an optimizing appointment scheduler to determine appointment intervals. Clinic mix influences patient waiting time, which was shorter with a 1 in 4 ratio of new to follow-up patients. In mixed clinics, new patients appointments are optimally spread throughout the clinic to reduce patient waiting time. In all new or all follow-up clinics, waiting time is improved if the appointment interval reflects the consultation time. Computer modelling can help in optimizing clinic management so improving the delivery of care in outpatient services.

Appointments and Schedules↗
PubMed1994

Operations research survey and computer simulation of waiting times in two medical outpatient clinic structures.

Outpatient services are increasingly recognised as an important component of health care provision and may be improved through the application of modern management techniques. We have performed a time and role audit of consultation and waiting times in two medical clinics using different queuing systems: namely, a serial processing clinic where patients wait in a single queue and a quasi-parallel processing clinic where patients are directed to the shortest queue to maintain clinic flow. Data collected were used to construct a computer simulation of patient flows in clinic. Assessment of patient satisfaction in the clinic process was determined using a self-administered questionnaire. Mean waiting time was shorter in the quasi-parallel processing clinic: 26 (SD 17) minutes compared with 36(24) minutes in the serial processing clinic. In the serial processing clinic 61% of patients waited more than 30 minutes compared with 41% in the quasi-parallel processing clinic. In the serial processing clinic 8% of 142 patients surveyed complained of the time spent waiting. The computer simulation we produced was able to determine waiting times with different clinic structures. The simulation showed that reductions in waiting time up to 30% might be achieved by changing our serial processing clinic to a quasi-parallel processing one. Performance of medical outpatient clinics can be improved by examining and changing clinic management. Computer simulation of outpatient clinics offers a means of assessing the impact of such changes on waiting time in clinic and on waiting lists.

Algorithms↗
PubMed1994

An object-oriented approach to knowledge representation in a biomedical domain.

An object-oriented approach has been applied to the different stages involved in developing a knowledge base about insulin metabolism. At an early stage the separation of terminological and assertional knowledge was made. The terminological component was developed by medical experts and represented in CORE. An object-oriented knowledge acquisition process was applied to the assertional knowledge. A frame description is proposed which includes features like states and events, inheritance and collaboration. States and events are formalized with qualitative calculus. The terminological knowledge was very useful in the development of the assertional component. It assisted in understanding the problem domain, and in the implementation stage, it assisted in building good inheritance hierarchies.

Algorithms↗
PubMed1993

The use of hypertext: demonstration of the methods for investigating an epidemic of meningitis.

The Meningitis Hypertext Case Study is a computer-assisted learning module developed by the Liverpool Epidemiology Programme as part of a comprehensive set of modules and case studies to assist health workers to learn epidemiology. The objectives of the case study are to highlight important concepts in diagnosing an epidemic of meningitis. It has been developed using hypertext software (LINKWAY) which allows interactions with other epidemiological software (EPI INFO) for the analysis of the data. The case study makes extended use of graphical displays, has a 'user-friendly' presentation and can be used by individuals and groups. Our initial experience indicates that this form of computer-assisted learning has considerable potential by providing users with an organized path through a series of problems set in a realistic environment. This could prove to be potentially useful in developing countries where up-to-date learning materials are often unavailable.

Computer-Assisted Instruction↗
PubMed1993

Medical informatics vocabulary.

In order that medical informaticians can create Open Systems for health care, they need to have a common language. Efforts in the 1980s at the National Library of Medicine to create a Medical Informatics Vocabulary (MIVoc) have been useful for document indexing purposes, but need to be continued and extended. The Committee of European Normalization Technical Committee 251 has created a project team for MIVoc, and that team has used both automatic and manual methods and referenced many sources in producing a vocabulary that has support from numerous experts in Europe. MIVoc has both a glossary and a tree structure. The glossary has about 250 terms with detailed definitions that include various explanations and pointers. One critical pointer is the semantic link to other terms in MIVoc from a which a tree-structure is inferred. The success of MIVoc clearly depends on its being used, which in the long run depends also on the vocabulary being maintained.

Humans↗
PubMed1989

Ranking documents with a thesaurus.

This article reports on exploratory experiments in evaluating and improving a thesaurus through studying its effect on retrieval. A formula called DISTANCE was developed to measure the conceptual distance between queries and documents encoded as sets of thesaurus terms. DISTANCE references MeSH (Medical Subject Headings) and assesses the degree of match between a MeSH-encoded query and document. The performance of DISTANCE on MeSH is compared to the performance of people in the assessment of conceptual distance between queries and documents, and is found to simulate with surprising accuracy the human performance. The power of the computer simulation stems both from the tendency of people to rely heavily on broader-than (BT) relations in making decisions about conceptual distance and from the thousands of accurate BT relations in MeSH. One source for discrepancy between the algorithms' measurement of closeness between query and document and people's measurement of closeness between query and document is occasional inconsistency in the BT relations. Our experiments with adding non-BT relations to MeSH showed how these non-BT non-BT relations to MeSH showed how these non-BT relations could improve document ranking, if DISTANCE were also appropriately revised to treat these relations differently from BT relations.

Abstracting and Indexing↗
PubMed1988

Mapping from GenBank to MEDLINE.

GenBank has been based largely on literature that provides nucleic acid sequences. To find additional literature that is relevant to a given sequence, a search of MEDLINE can prove helpful. This paper documents some of the similarities between GenBank and MEDLINE that facilitate retrieval of documents from MEDLINE. In particular, techniques and examples are presented which take GenBank information and lead to MEDLINE information that supplements the GenBank information.

Abstracting and Indexing↗
PubMed1987

A vocabulary for medical informatics.

The terminology in medical informatics is evolving rapidly. The organizers of MEDINFO and SCAMC have used different sets of keywords to index their documents. Recognizing the limitations of this approach, members of those organizations joined with the National Library of Medicine in the creation of a better terminology for medical informatics. A hierarchical structure was placed on the terms to produce a thesaurus typical of the sort often used in the indexing and retrieving of documents. The building of this thesaurus began with an automatic merging of the thesaurus used by the Association of Computing Machinery and the Information Sciences component of the "Medical Subject Headings." This product was pruned by eliminating terms not related to those in the MEDINFO keyword list or not in the medical informatics literature. Further refinement of the thesaurus resulted from extensive discussions among the authors of this paper. The first major application of this terminology has been to the indexing of the articles in "MEDINFO-86 Proceedings." Major components of this medical informatics thesaurus also have been incorporated into the "Medical Subject Headings." This paper describes the process of preparing the thesaurus and presents an evaluation of its coverage of the "MEDINFO-86 Proceedings."

Abstracting and Indexing↗
PubMed1987

Searching for patterns in the MeSH vocabulary.

NLM revises its MeSH vocabulary annually to reflect changes in biomedical literature and the health sciences community. This study tested two hypotheses about NLM's MeSH vocabulary. The first is that new terms are added to MeSH when their broader terms have an increased number of postings. One examination compared the number of postings for the broader terms of new and existing terms in the current MEDLINE file; the other compared them over time. No significant statistical difference was found in either case. A second hypothesis--that there is a relationship between the patterns of MEDLINE indexing and searching and the organization of the MeSH tree structure--was tested by comparing the distribution of searched terms in the MeSH trees with the distribution of all terms. It was found that certain trees are searched more often than could be predicted by the overall term distribution, while others are searched less frequently than expected. In summary, (1) new terms cannot be predicted by the increase in postings of existing terms, and (2) searchers' and indexers' use of the terms' tree structure does not correlate with the terms' distribution in the MeSH trees.

Abstracting and Indexing↗
PubMed1982

Evolutionary search: gradients and information.

To better understand evolution one might view evolution as a search algorithm proceeding through a search space. The search method implemented by reproduction with mutation and selection of the fit does not perform efficiently on many search spaces. Characteristics of the search space are critically important to the effectiveness of the search algorithm. The "gradients" of and the "information" in a search space are used in this paper to study performance of "evolutionary" search algorithms.

Animals↗
PubMed1981

Evolution and gradualness.

Evolutionary systems are commonly considered to have fundamental properties: (1) elements (or organisms) in the system reproduce with mutation and (2) only the fit elements survive. I propose that evolutionary systems have a third property - the property of gradualness. A system has gradualness, if, and only if, small changes in an element usually lead to small changes in that element's fitness. I have formalized a framework from which attempts to design evolutionary systems might proceed. Of particular importance are the criteria, based on the notion of perpetuation, which a system's behavior must satisfy in order to be considered evolutionary. By my standards, no computer programs have been designed that manifest meaningful evolutionary behavior.

Biological Evolution↗
PubMed1981

Searching and gradualness.

Consider the elements of the power set S as the alternatives in a search space. Each element of the set has a value and the goal of a search is to find an element with near-minimum value. If high-valued elements of cardinality i (recall that elements of S are themselves sets) are subsets of high-valued elements of cardinality i + 1, then the search space has a king of gradualness that should facilitate search. A search algorithm might generate a series, S' (1), . . . S' (k) of samples in S, where all the elements in S' (i) have cardinality i. I propose a class of search algorithms, where each algorithm A(j) generates S' (i + 1) by emphasizing the j lowest-valued elements in S' (i). I then define search space gradualness and search algorithm performance and formally relate gradualness and performance.

Biological Evolution↗