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Biomedical subjects

R A Miller

Publications and source records attributed to R A Miller.

At least 253 records · Page 14Linked to original sources
PubMed1991

Heuristic determination of quantitative data for knowledge acquisition in medicine.

Knowledge acquisition for medical knowledge bases can be aided by programs that suggest possible values for portions of the data. The paper presents an experiment which was used in designing a heuristic to help the process of knowledge acquisition. The heuristic helps to determine numerical data from stylized literature excerpts in the context of knowledge acquisition for the QMR medical knowledge base. Quantitative suggestions from the heuristics are shown to agree substantially with the data incorporated in the final version of the knowledge base. The experiment shows the potential of knowledge base specific heuristics in simplifying the task of knowledge base creation.

Artificial Intelligence↗
PubMed1991

Accumulation of hyporesponsive, calcium extruding memory T cells as a key feature of age-dependent immune dysfunction.

In this review I propose a hypothesis with a number of testable predictions: that the age-dependent decline in T lymphocyte function is largely the result of the accumulation of memory T lymphocytes with over-active plasma membrane calcium pumps. This idea is consistent with much, though not all, of the currently available data. I will start by presenting the evidence that suggested and most clearly supports this idea, then discuss apparently contrary data (some of it still difficult to reconcile with the model), and lastly consider the implications of the model for our understanding of late life development of the T cell immune system.

Aging↗
PubMed1991

Extrusion of calculi from upper urinary tract into perinephric and periureteric tissues during endourologic stone surgery.

We report on 11 patients in whom fragments of calculi were extruded into the perinephric or periureteric tissues at the time of endourologic stone surgery. All patients have been managed conservatively. In 2 patients ureteric strictures developed, but these were probably secondary to an electrical injury as a result of electrohydraulic lithopaxy. The remaining 9 patients have not experienced serious sequelae as a result of the calculus extrusion.

Humans↗
PubMed1991

Distinguishing drug toxicity syndromes from medical diseases: a QMR computer-based approach.

Drug effects can mimic a wide variety of diseases. Experts note that adverse drug reactions (ADRs) have become the 'greatest imitator' of disease in clinical medicine. Quick Medical Reference (QMR) is a decision support system providing diagnostic data about more than 600 medical diseases. Currently, QMR contains only limited drug information. Just as physicians have difficulty diagnosing ADRs, QMR has similar problems in differentiating natural disease manifestations from drug toxicity syndromes. To remedy this problem, two prototype Drug Syndromes (DS), Carbamazepine Toxicity and Penicillin Toxicity, were incorporated into the QMR Knowledge Base (KB). Using detailed case reports, we demonstrated that a DS-augmented version of QMR was successful in discriminating these DS from the other diseases in QMR's KB. The addition of DS significantly improves QMR's diagnostic performance in cases in which some of the pathologic features are the consequence of drugs.

Aged↗
PubMed1991

Aging and immune function.

Since it is too difficult to study aging of the organism as a whole, most investigators try to focus on a specific physiological system that exhibits age-dependent functional changes, in the hopes that elucidation (in biochemical and developmental terms) of the mechanism of senescent change will provide insight into the aging process itself. The immune system is among the most maleable of such models, in that well-defined cell types will produce well-defined molecules with predictable functions in vitro and in vivo. The increasing power of basic immunological science should, in the next decade, permit an increasingly fine appreciation of how aging leads to immune decline. This expanding conceptual framework will then suggest new ideas about the role of immunosenescence in degenerative, infectious, and neoplastic illnesses and may also generate increasingly rational strategies for therapeutic intervention.

Aging↗
PubMed1991

Transurethral resection of prostate under sedation and local anesthesia (sedoanalgesia). Experience in 100 patients.

One hundred male patients (average age 68.2 yrs) with acute retention (n = 20) or with symptoms of outflow obstruction (n = 80) underwent transurethral resection of the prostate (TURP) under sedation (midazolam) and local anesthesia (lidocaine)--referred to as sedoanalgesia technique. Procedures lasted twenty-four minutes on average (range 15-35 min), and the weight of prostatic tissue resected ranged from 2-35 g (average 11.1 g). There were no complications related to the use of midazolam or lidocaine. The technique of sedoanalgesia proved safe and acceptable to all patients regardless of their pre-existing medical condition. Where the weight of prostate to be resected is estimated to be less than 40 g, TURP under sedoanalgesia proves an effective alternative to general or regional anesthesia.

Aged↗
PubMed1991

Increased stimulatory G protein in neoplastic human thyroid tissues.

Prior studies in our laboratory have shown that thyroid neoplasms produce increased amounts of cyclic adenosine monophosphate (cAMP). Thyroid-stimulating hormone receptors act through the stimulatory G protein (Gs) to activate adenylate cyclase, the enzyme responsible for cAMP production. The purpose of this study is to measure the activity and amount of Gs in human normal and neoplastic thyroid tissue to see whether alterations in Gs are responsible for the increased cAMP production seen in thyroid neoplasms. Four tumors with a high TSH-stimulated cyclase activity of 497.6 +/- 71.9 pmol/mg/30 min versus 35.9 +/- 13.5 pmol/mg/30 min for normal tissue from the same patients were studied. In reconstitution studies measuring Gs activity, neoplastic thyroid tissue produced 637 +/- 106 pmol cAMP/mg S49/mg thyroid membrane min versus 363 +/- 133 pmol cAMP/mg 549/mg thyroid membrane/min produced by normal thyroid tissue. Qualitative assessments of the amount of Gs present with cholera toxin-mediated adenosine diphosphate ribosylation showed increased Gs in thyroid tumors. Western blotting with antibodies directed against Gs showed a 3.3 +/- 0.6-fold increase in the amount of Gs in these thyroid tumors. These experiments identify an increase in the amount of an otherwise normal Gs as the biochemical defect responsible for the increased cAMP production in this group of tumors.

Adenocarcinoma↗
PubMed1991

Leprosy and AIDS: a review of the literature and speculations on the impact of CD4+ lymphocyte depletion on immunity to Mycobacterium leprae.

The potent effects of HIV infection on the human immune system, the complexity of the host-parasite interaction in leprosy, and the paucity of current information on the natural history of co-infected patients makes this area a fertile ground for clinical and immunologic investigation. Several studies have now validated the prediction that there exists a large cohort of patients, particularly in Africa, who are concurrently infected with HIV and M. leprae. Sparse but tantalizing evidence suggests that infection with HIV may increase the incidence of leprosy among individuals with subclinical infection with M. leprae, either through shortening the incubation period or by increasing disease penetrance. Similarly, active mycobacterial disease may accelerate the course of HIV disease, as has been postulated to occur during concurrent infections with certain other viral and bacterial pathogens in HIV-positive patients. A subtle and complex interplay between HIV and leprosy may thus result which will impact the observed epidemiology of both illnesses in regions where both are prevalent. Possible effects of the HIV epidemic on leprosy control programs have been outlined by the World Health Organization and in an editorial by Turk and Rees. The published experience provides few guidelines for the clinical care of co-infected patients. The initial response to conventional therapeutic regimens appears to be excellent, but no follow-up data have been included. The possible absence of ENL in these patients would simplify care for multibacillary disease, if this observation is confirmed in larger field studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1991

Chronic steroid dependent asthma and pulmonary function.

The authors followed 84 asthma clinic patients, with an average age of 49 years, for 12 years. Pulmonary function studies consisting of forced expiratory volume in one second and forced vital capacity were performed upon initial evaluation and quarterly re-evaluation.

Asthma↗
PubMed1991

Sedation for day-case urology: an assessment of patient recovery profiles after midazolam and flumazenil.

The specific antagonist flumazenil has been shown to reverse the central actions of benzodiazepines. Its use, in day-case procedures performed under benzodiazepine sedation, offers the potential for enhanced patient recovery. However, concern has been expressed over the possibility of resedation given the short elimination half-life of flumazenil. A randomised, double-blind, placebo controlled trial was therefore designed to assess patient recovery profiles after flumazenil. A total of 44 adults were entered into the trial. Recovery was assessed by means of a battery of psychomotor tests performed pre- and postoperatively. Psychomotor function in patients receiving flumazenil returned to, or near to, baseline levels within 15 min of administration--an improvement maintained throughout the 6 h test period. Patients receiving placebo did not recover fully until the 2 h test point--significant differences between the two groups existing at 15 min and 1 h. In this study, flumazenil effectively reversed midazolam-induced sedation without evidence of resedation. The implications for day-case surgery are discussed.

Adult↗
PubMed1991

Beds or day case unit: your choice?

The aim of this study was to assess the amount of day case surgery and potential day case surgery being performed in the main theatre block of a District General Hospital, which had a thriving Day Case Unit. Our results revealed that as well as large numbers of potential day cases being performed as inpatients, many patients (both potential day cases and long-stay elective surgery patients) are spending a day(s) in hospital prior to the day of surgery. We believe that by performing all day case surgery in our Day Case Unit and by using the Day Case Unit to perform pre-admission screening on all surgical patients, a large number of bed days will become available. These beds may be used for elective or emergency admissions. Alternatively, cutting surgical beds will free monies which can be spent on the Day Case Unit.

Ambulatory Surgical Procedures↗
PubMed1991

A tool for the computer-assisted creation of QMR medical knowledge base disease profiles.

QMR-KAT is a computer-based tool which assists physicians in the construction of the QMR medical knowledge base. Each QMR disease profile results from an in-depth analysis of the published medical literature, and from consultations with expert clinicians. QMR-KAT is an interactive knowledge acquisition program which facilitates the creation of new disease profiles, records the supporting evidence for each disease profile entry, and enforces consistency with the existing knowledge base. The program has been used in the creation of all new QMR disease profiles over the past two years. It has also been used to support a study on the reproducibility of knowledge base construction.

Artificial Intelligence↗