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Biomedical subjects

R A Miller

Publications and source records attributed to R A Miller.

At least 181 records · Page 10Linked to original sources
PubMed1995

Efficacy of first-time steroid injection for painful heel syndrome.

The purpose of this study was to evaluate the results of a single injection of corticosteroids in patients with painful heel syndrome. Twenty-seven heels in 24 patients were injected with a combination of 1 ml of lidocaine and 1 ml of betamethasone (6 mg). These patients had never previously received an injection to their heels and had continued symptoms of pain after a trial of other nonoperative treatment modalities. After the injection, patients were seen and surveyed periodically for a period of 5 months to 8 months. The amount of pain relief that they obtained, the length of time this lasted, and the amount of heel pain present at the final follow-up were recorded. Based on the results of our study, we believe that a steroid injection is a reasonable adjunct in the treatment of painful heel syndrome, but that it is unlikely to provide permanent pain relief.

Adult↗
PubMed1995

Primary nocturnal enuresis: a urodynamic study spanning three generations.

The familial incidence of primary nocturnal enuresis is well recognised. Twin studies suggest there to be a significant genetic component to the aetiology of this disorder. However, family studies to date have been based on symptomatic enquiry alone although detrusor instability is a recognised feature of primary noctural enuresis in 70-80% of cases. For the first time we describe a family of adults with urodynamically proven instability spanning three generations. The pattern of inheritance lends support to the proposition that such detrusor instability is transmitted as an autosomal dominant characteristic.

Adult↗
PubMed1995

Temporal reasoning abstractions in QMR.

A medical decision-support system (MDSS) employs either explicit or implicit temporal representation and reasoning (TRR). In this paper we first examine the factors that make explicit TRR necessary. We argue that for diagnostic MDSSs in large domains, such as internal medicine, implicit TRR is often sufficient for acceptable diagnostic performance. A necessary prerequisite for implementing implicit TRR is the identification of a set of proper TRR abstractions. We analyze the implicit TRR utilized in QMR, a MDSS operating in the domain of general internal medicine, and describe three classes of TRR abstractions. We discuss our findings in relation to work on temporal reasoning in medical informatics.

Animals↗
PubMed1995

On the heuristic nature of medical decision-support systems.

In the realm of medical decision-support systems, the term "heuristic systems" is often considered to be synonymous with "medical artificial intelligence systems" or with "systems employing informal model(s) of problem solving". Such a view may be inaccurate and possibly impede the conceptual development of future systems. This article examines the nature of heuristics and the levels at which heuristic solutions are introduced during system design and implementation. The authors discuss why heuristics are ubiquitous in all medical decision-support systems operating at non-trivial domains, and propose a unifying definition of heuristics that encompasses formal and ad hoc systems. System developers should be aware of the heuristic nature of all problem solving done in complex real world domains, and characterize their own use of heuristics in describing system development and implementation.

Artificial Intelligence↗
PubMed1994

Isoprene, an endogenous hydrocarbon and industrial chemical, induces multiple organ neoplasia in rodents after 26 weeks of inhalation exposure.

Isoprene, the 2-methyl analogue of 1,3-butadiene, is a high production chemical used largely in the manufacture of synthetic rubber and is the major endogenous hydrocarbon exhaled in human breath. Thirteen-week inhalation toxicology studies of isoprene were conducted in male and female F344 rats and B6C3F1 mice at exposure concentrations of 0, 70, 220, 700, 2200, and 7000 ppm (6 h/day; 5 days/week). In addition, 26-week inhalation studies at the same exposure levels, followed by a 26-week recovery period, were conducted in male rats and mice. The 13-week exposures produced no discernible exposure-related toxic effects in rats. Interstitial cell hyperplasia of the testis was observed in all male rats in the 7000 ppm group after 26 weeks of exposure; following the 26-week recovery period the only effect in rats was a marginal increase in benign testicular interstitial cell tumors. In mice, isoprene induced toxic and carcinogenic effects at multiple organ sites. Following the 26-week exposure and 26-week recovery periods, incidences of neoplastic lesions in the liver, lung, forestomach, and harderian gland were significantly increased. Neoplastic effects were observed at 700 ppm and higher exposures. Non-neoplastic lesions in mice exposed to isoprene included spinal cord degeneration, testicular atrophy, degeneration of the olfactory epithelium, and epithelial hyperplasia of the forestomach. A partial hindlimb paralysis and a nonresponsive macrocytic anemia were also seen in mice. Most of the toxic and carcinogenic effects caused by isoprene, as well as the species' difference in response, had been observed after inhalation exposures to 1,3-butadiene.

Adenoma↗
PubMed1994

The use of epidemiological concepts and techniques to discern factors associated with the nitrate concentration of well water on swine farms in the USA.

This epidemiological study investigates the relationship between various factors associated with swine farms and the nitrate concentration of well water in the USA. Through a random sampling procedure, 605 swine farms located in 18 states were selected for inclusion in this study. A total of 631 well water samples were collected from these farms and tested for a variety of elements and compounds. The concentrations of nitrate, nitrite, sulfate, chloride, sodium, potassium, ammonia, fluoride, bromide and lithium were determined by an ion chromatograph while an inductively coupled argon plasma emission spectrophotometer was used to determine the concentrations of calcium, magnesium, barium, zinc, iron and phosphate. Data concerning various farm factors were gathered via a personally administered questionnaire. The data were examined using both multiple linear regression and logistic regression. Results indicate that 53.6% (338/631) of the wells contained detectable levels of nitrate, 11.7% (74/631) had nitrate levels exceeding 45 ppm and 4.3% (27/631) exceeded 100 ppm. Logistic models demonstrated an association between nitrate concentrations > 45 ppm, increasing water potassium levels and wells < 100 ft deep. Nitrate levels > 100 ppm were related to increasing water concentrations of potassium, magnesium, barium and zinc, wells 6-10 years old, increasing distance from the study farm to the nearest cattle farm and a greater distance to the nearest waterway located off the study farm. A negative association was seen between nitrate concentrations > 100 ppm, the water level of sulfate, and the use of the same well to supply both the household and livestock. Multiple linear regression models revealed a positive association between increasing nitrate concentration and the water levels of chloride, calcium, zinc and the greater number of miles from the study farm to the nearest farm with cattle or sheep. A negative association was noted between the concentration of well water nitrate and the water levels of sulfate and ammonia, the use of water treatment, the number of miles to the nearest farm with poultry, the employment of water treatment and the use of the same well to supply water to both livestock and the household.

Agriculture↗
PubMed1994

Extrusion of the P glycoprotein substrate rhodamine-123 distinguishes CD4 memory T cell subsets that differ in IL-2-driven IL-4 production.

Approximately 25% of T cells in young mice are able to extrude the fluorescent P glycoprotein substrate Rhodamine-123 (R123), and these R123low cells are present within the naive and memory cell populations of both CD4 and CD8 type. The proportion of R123low T cells increases with age to approximately 60% in mice older than 18 mo of age. CD4 memory T cells from young mice secrete more IL-4 compared with cells from old donors when activated by anti-CD3 and further cultured for 7 to 10 days in the presence of IL-2. To determine whether this age-related decline in IL-4 production was related to the parallel accumulation of R123low T cells within the CD4 memory subset, we compared IL-4 production in cell preparations enriched for R123high and R123low cells by electronic cell sorting. IL-2-driven IL-4 production by CD3-activated CD4 memory cells was found to be limited almost entirely to the R123high subset, i.e., the subset that declines with age. Proliferation under these culture conditions also declined with age and was also much more vigorous in R123high than in R123low cells. Not all R123low T cells, however, were resistant to IL-2-dependent proliferation and differentiation: limit dilution analyses showed nearly equal proportions of Con A-responsive proliferative and cytotoxic clones within the R123high and R123low subsets of CD8 naive cells. These data show that P glycoprotein-mediated extrusion of R123 delineates CD4 memory T cell subsets that differ in function.(ABSTRACT TRUNCATED AT 250 WORDS)

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Age-associated changes in human T cell phenotype and function.

We used a limiting dilution method to estimate the proportion of T lymphocytes that could respond to PHA by producing IL-2, in peripheral blood mononuclear cells from healthy adult donors ranging in age from 18 to 81 years. The donors were selected using the guidelines of the SENIEUR protocol to exclude samples from donors not in optimal health. The frequency of PHA responsive, IL-2 producing T cells was found to decline with age, even though there was no corresponding change in the proportions of cells expressing the CD3 or CD4 determinants. There was, however, a statistically significant increase in the proportion of CD4 and CD8 cells expressing the CD45R0 determinant, thought to be a marker for memory T cells, and a corresponding decline in cells expressing the CD45RA marker found on naive peripheral T cells. The decline in the proportion of mitogen-reactive T cells in older donors, although statistically significant, was smaller than that seen in studies of aging mice, probably because the assay conditions for human T cell function are preferentially stimulatory for memory T cells, which accumulate in old age.

Adolescent↗
PubMed1994

Age-sensitive T cell phenotypes covary in genetically heterogeneous mice and predict early death from lymphoma.

We have assessed several age-sensitive indicators of immune status in young (i.e., 6 to 11-month-old) mice of a genetically heterogeneous population to see if these varied in parallel and to determine if one or more of the status indices predicted life span or cancer incidence. We report that the number of memory (i.e., CD44hi) T cells within the CD8 subset is correlated with number of memory cells in the CD4 population, and inversely correlated with the number of naive (i.e., CD45RBhi) CD4 cells at both 6 and 11 months of age, suggesting that the conversion of naive to memory cells may occur at similar rates in both T cell subsets. Mice that ranked high in the proportion of memory T cells (within the CD4 and CD8 pools) at 6 months of age tended to retain their ranking at 11 months, suggesting that the pace or extent of memory cell formation may be a consistent trait that distinguishes mice at least within a genetically heterogeneous population. Mice that at 6 months of age exhibited high levels of CD4 or CD8 memory T cells, low levels of naive CD4 cells, or low levels of T cells able to proliferate in response to Con A and IL-2 were found to be significantly more likely than their littermates to die within the first 18 months of life. Cases of follicular cell lymphoma, lymphocytic and lymphoblastic lymphoma, and hepatic hemangiosarcoma were seen within the group of mice dying at early ages.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1994

Plain radiographic interpretation in trimalleolar ankle fractures poorly assesses posterior fragment size.

Twenty-five patients with trimalleolar ankle fractures were evaluated using both conventional radiography and computed tomography (CT) to determine the size of the posterior fragment along with other fracture characteristics. Plain radiograph measurements indicated very poor inter- and intraexaminer reliability. When compared to the CT scan measurement, 54% of the plain radiographic readings revealed > 25% error. Plain radiographic interpretations erred in most cases by overrating the size of the fragment, but major underestimations also occurred. The larger size fragments showed more error than the smaller ones. This information confirms our clinical suspicion that the lateral radiograph is unreliable in assessing the posterior fragment size.

Ankle Injuries↗
PubMed1994

Expression of shared idiotypes by paraproteins from patients with monoclonal gammopathy of undetermined significance.

We have previously demonstrated the expression of shared idiotypes by the paraproteins from approximately one-quarter of patients with multiple myeloma (MM). We have now investigated whether similar cross-reactivity is expressed in the paraproteins of patients with monoclonal gammopathy of undetermined significance (MGUS), using a panel of 32 monoclonal antibodies (MAB) generated against follicular B cell lymphomas. The paraproteins from 76/409 (19%) patients with MGUS reacted with at least one of 23 different anti-idiotypic antibodies used in this study. 18 MABs demonstrated reactivity with more than one patient's paraprotein. Moreover, 10 MABs reacted frequently (with 5-22 paraproteins). Over half (41/76) of the reactive patients' paraproteins reacted with more than one MAB from this panel. This frequency of anti-idiotypic reactivity was similar to that of previously studied patients with myeloma, chronic lymphocytic leukaemia (CLL), and follicular B-cell lymphomas. There was no correlation between specific anti-idiotypic reactivity and the propensity to develop serious disease (MM, macroglobulinaemia, amyloidosis, or other lymphoproliferative disorders) in patients with MGUS. These results suggest that MGUS is derived from cells producing antibodies that are similar to those of other B-cell malignancies and that the pattern of idiotype expression is irrelevant to malignant potential.

Antibodies, Monoclonal↗
PubMed1994

Walk-in, walk-out day case genito-scrotal surgery with sedation reversal. A survey of patient attitudes and morbidity.

OBJECTIVES: To survey patient attitudes and assess the extent of patient morbidity in the first 24 h following walk-in, walk-out day case genito-scrotal surgery with sedation reversal. PATIENTS AND METHODS: One hundred patients who were undergoing genito-scrotal surgery were eligible for inclusion in the study. All patients walked into theatre, positioned themselves on the operating table and were sedated with intravenous (i.v.) midazolam (Hypnovel, Roche Products Ltd, Welwyn, UK) following which the appropriate local anaesthetic block was performed. One minute before the end of surgery sedation was reversed with an i.v. injection of 0.5 mg flumazenil (Anexate, Roche Products Ltd). When conscious and alert (approx. 2 min), patients were allowed to get themselves up off the operating table and walk from theatre. All patients were given a questionnaire to complete and were reviewed 2 weeks after surgery. RESULTS: Eighty-six of 100 patients returned questionnaires. Fifty-five patients were asymptomatic and no patient experienced nausea or vomiting in the first 24 h post-operatively. Other symptoms such as headache (2%), drowsiness (20%) and dizziness (11%) were uncommon and significantly less frequent than seen with general anaesthetic procedures. Seventeen patients described minor wound complications and one patient with a scrotal haematoma was readmitted for overnight observation. Nearly all patients (98%) expressed their satisfaction with the technique. CONCLUSION: Walk-in, walk-out day case surgery as described is a well-tolerated technique with a low morbidity and towards which patients have a positive attitude.

Adolescent↗
PubMed1994

Absorption characteristics of lignocaine following intravesical instillation.

The systemic absorption of topical lignocaine applied intravesically was studied in 11 patients with indwelling catheters. Group A patients (n = 9) had lignocaine 400 mg (as 40 ml of a 1% solution) instilled into the bladder for 1 hour whilst in Group B patients (n = 2) the application was for 2 hours. The mean maximum lignocaine concentration measured in Group A patients was 121 ng ml-1 with a time to maximum concentration of 60-90 minutes. The two patients in Group B had corresponding values of 410 and 1580 ng ml-1 respectively at 120 minutes. Transitional cell epithelium, like intact skin, constitutes a significant barrier to the uptake of topically applied lignocaine which, from the bladder, is both slow and limited. Intravesical application is safe (maximum levels in Group A patients being x 30 less than the minimal toxic level of lignocaine) but its clinical efficacy remains to be determined.

Absorption↗