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Biomedical subjects

R M Miller

Publications and source records attributed to R M Miller.

At least 19 recordsLinked to original sources
PubMed1995

Application of an electrocardiographic inverse solution to localize ischemia during coronary angioplasty.

Localization of Ischemia. This study demonstrates the utility of an electrocardiographic inverse solution, coupled with body surface potential mapping (BSPM), in localizing acute ischemia in patients undergoing percutaneous transluminal coronary angioplasty (PTCA). PTCA balloon inflations produce complete occlusion and acute transient ischemia, which can be detected electrocardiographically with BSPM. Comparisons between maps recorded both during and before the inflation of the PTCA balloon allow patient- and artery-specific characterizations of the resulting ischemia. Knowledge of the patient's coronary anatomy and the location of the occlusion site by coronary angiography permit an estimation based on cardiac hemodynamics of the region of myocardium most likely to suffer from PTCA-induced ischemia. Electrocardiographic inverse solutions provide a means of predicting cardiac potentials from body surface maps. In this study, we describe an inverse solution we have developed to localize the transient ischemia produced by PTCA. To validate the procedure, we compared the locations of predicted ischemia in seven patients with a qualitative estimate of the perfusion region based on fluoroscopic examination of each patient's coronary anatomy and PTCA balloon location. In each case, the region of ischemia predicted by the model included the perfusion zone determined fluoroscopically. These results suggest that electrical changes induced by acute ischemia can be localized with an electrocardiographic inverse solution.

Angioplasty, Balloon, Coronary↗
PubMed1995

Biosurfactant-facilitated remediation of metal-contaminated soils.

Bioremediation of metal-contaminated wastestreams has been successfully demonstrated. Normally, whole cells or microbial exopolymers are used to concentrate and/or precipitate metals in the wastestream to aid in metal removal. Analogous remediation of metal-contaminated soils is more complex because microbial cells or large exopolymers do not move freely through the soil. The use of microbially produced surfactants (biosurfactants) is an alternative with potential for remediation of metal-contaminated soils. The distinct advantage of biosurfactants over whole cells or exopolymers is their small size, generally biosurfactant molecular weights are less than 1500. A second advantage is that biosurfactants have a wide variety of chemical structures that may show different metal selectivities and thus, metal removal efficiencies. A review of the literature shows that complexation capacities of several bacterial exopolymers was similar to the complexation capacity of a rhamnolipid biosurfactant produced by Pseudomonas aeruginosa ATCC 9027.

Metals↗
PubMed1994

Treatment efficacy for adults with oropharyngeal dysphagia.

Over the last 10 years, the literature in the area of oropharyngeal dysphagia has focused on treatment techniques for specific medical conditions and the documentation of treatment efficacy. Increasingly, there has been multidisciplinary involvement in the study of swallowing physiology and dysphagia. Investigators have used a wide range of technologies in quantifying changes in swallowing physiology as a result of imposed therapeutic adjustments and maneuvers. Group studies and single case design investigations have attempted to address the question of treatment efficacy. This article addresses the status of clinical treatment and the future needs for research.

Central Nervous System Diseases↗
PubMed1994

Behavioral treatment for adults with oropharyngeal dysphagia.

Oropharyngeal dysphagia has been treated by various professionals for many years, with increasingly more attention paid to this disorder by speech-language pathologists in the past decade. There has been a gradual change in emphasis in the literature, from early anecdotal accounts to more scientific, controlled studies that have tested the outcomes and effectiveness of certain techniques or programs. This article reviews the literature in the area of behavioral treatment for oropharyngeal dysphagia, with a critical look at the current state of knowledge. General treatment programs and techniques developed to facilitate or compensate for specific swallowing disorders are summarized.

Behavior Therapy↗
PubMed1994

Effect of a Pseudomonas rhamnolipid biosurfactant on cell hydrophobicity and biodegradation of octadecane.

In this study, the effect of a purified rhamnolipid biosurfactant on the hydrophobicity of octadecane-degrading cells was investigated to determine whether differences in rates of octadecane biodegradation resulting from the addition of rhamnolipid to four strains of Pseudomonas aeruginosa could be related to measured differences in hydrophobicity. Cell hydrophobicity was determined by a modified bacterial adherence to hydrocarbon (BATH) assay. Bacterial adherence to hydrocarbon quantitates the preference of cell surfaces for the aqueous phase or the aqueous-hexadecane interface in a two-phase system of water and hexadecane. On the basis of octadecane biodegradation in the absence of rhamnolipid, the four bacterial strains were divided into two groups: the fast degraders (ATCC 15442 and ATCC 27853), which had high cell hydrophobicities (74 and 55% adherence to hexadecane, respectively), and the slow degraders (ATCC 9027 and NRRL 3198), which had low cell hydrophobicities (27 and 40%, respectively). Although in all cases rhamnolipid increased the aqueous dispersion of octadecane at least 10(4)-fold, at low rhamnolipid concentrations (0.6 mM), biodegradation by all four strains was initially inhibited for at least 100 h relative to controls. At high rhamnolipid concentrations (6 mM), biodegradation by the fast degraders was slightly inhibited relative to controls, but the biodegradation by the slow degraders was enhanced relative to controls. Measurement of cell hydrophobicity showed that rhamnolipids increased the cell hydrophobicity of the slow degraders but had no effect on the cell hydrophobicity of the fast degraders. The rate at which the cells became hydrophobic was found to depend on the rhamnolipid concentration and was directly related to the rate of octadecane biodegradation.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkanes↗
PubMed1994

Optimal imaging techniques for locating leaflets after escape from prosthetic heart valves.

The authors report two cases of leaflets escaping from an Edwards-Duromedics bileaflet prosthetic heart valve (Baxter-Edwards Division, Baxter Healthcare Corp., Irvine, Calif.). Several imaging techniques were used in attempts to locate the leaflets. Only computed tomography (CT) led to conclusive results. Because progressive extrusion through the arterial wall was documented surgically in these cases, the authors recommend that CT be performed as early as possible after a leaflet escapes, even in asymptomatic patients. Extrusion through the arterial wall precludes percutaneous intravascular movement or retrieval of escaped leaflets.

Adult↗
PubMed1992

Patient tolerance of ioxaglate and iopamidol in internal mammary artery arteriography.

To compare discomfort caused by ioxaglate and iopamidol, 25 patients scheduled for coronary angiography including internal mammary arteriography were studied. Each patient received both agents. Data were available on 22 randomly selected patients who completed the protocol. Two patients were withdrawn because of unsuccessful internal mammary artery cannulation and one because of idiosyncratic reaction to diazepam. After the internal mammary artery injections, the short-form McGill Pain Questionnaire (SF-MPQ) was completed to evaluate the patient response. Ioxaglate caused significantly less discomfort than iopamidol. Word scale (WS) p less than .05; visual analog scale (VAS) p less than .05. We conclude that ioxaglate is much better tolerated than iopamidol in internal mammary arteriography.

Adult↗
PubMed1992

Snail predation by larvae of Sepedon scapularis Adams (Diptera: Sciomyzidae), a potential biocontrol agent of snail intermediate hosts of schistosomiasis in South Africa.

Malacophagous larvae of the fly Sepedon scapularis Adams were shown experimentally to be effective predators of three species of aquatic pulmonate snails tested as prey: Bulinus africanus (Krauss) an important intermediate host of Schistosoma haematobium (Bilharz), Bulinus tropicus (Krauss) and the invasive species Physa acuta Draparnaud. Survival of S. scapularis larvae from instar to instar was negatively affected by the size of prey snails, since larvae tended to be asphyxiated by the mucous secretions of the snails, or by the larval hydrofuge hairs becoming entangled in snail faeces. In experiments to test the choice of S.scapularis larvae for different species and sizes of snails, B.africanus was significantly disfavoured compared with the other two snail species. Small snails (< 3 mm) were more frequently killed by all three larval instars of S.scapularis. First instars killed few, if any, large snails (> 7 mm), whereas second and third instars preyed effectively on all sizes of snails. Third instars killed significantly more snails than younger instars. For larvae offered only one species of snail as prey, the mean total number of snails killed per larva during its entire development was 49 B.africanus, 45 B.tropicus or 34 P.acuta. It is concluded that S.scapularis is potentially useful as a biological control agent for use against indigenous Bulinus and exotic Physa snails.

Analysis of Variance↗
PubMed1992

Enhanced octadecane dispersion and biodegradation by a Pseudomonas rhamnolipid surfactant (biosurfactant).

A microbial surfactant (biosurfactant) was investigated for its potential to enhance bioavailability and, hence, the biodegradation of octadecane. The rhamnolipid biosurfactant used in this study was extracted from culture supernatants after growth of Pseudomonas aeruginosa ATCC 9027 in phosphate-limited proteose peptone-glucose-ammonium salts medium. Dispersion of octadecane in aqueous solutions was dramatically enhanced by 300 mg of the rhamnolipid biosurfactant per liter, increasing by a factor of more than 4 orders of magnitude, from 0.009 to > 250 mg/liter. The relative enhancement of octadecane dispersion was much greater at low rhamnolipid concentrations than at high concentrations. Rhamnolipid-enhanced octadecane dispersion was found to be dependent on pH and shaking speed. Biodegradation experiments done with an initial octadecane concentration of 1,500 mg/liter showed that 20% of the octadecane was mineralized in 84 h in the presence of 300 mg of rhamnolipid per liter, compared with only 5% octadecane mineralization when no surfactant was present. These results indicate that rhamnolipids may have potential for facilitating the bioremediation of sites contaminated with hydrocarbons having limited water solubility.

Alkanes↗
PubMed1992

A cost-effectiveness study of the management of intractable urinary incontinence by urinary catheterisation or incontinence pads.

STUDY OBJECTIVE: The aim was to compare the costs and effects of management of intractable urinary incontinence by urinary catheterisation or incontinence pads. DESIGN: This was a prospective, randomised study comparing catheterisation with pads, supplemented by additional data collected from patients with chronic indwelling catheters. Main outcome measures were costs of equipment, nursing time, patient preference, nursing preference, and clinical and bacteriological assessment of urinary infection. SUBJECTS: 78 intractably incontinent elderly female patients were randomly allocated to management by urinary catheter or pads and toileting. Supplementary data on equipment costs and nursing time were collected from 27 patients, of whom 22 were already catheterised at the time of the randomisation and five were catheterised by the nursing staff after the last date for entry into the randomisation. MAIN RESULTS: Of the 38 patients randomised to catheterisation, 14 refused consent so only 24 were catheterised on day 1 of the study. There was a rapid removal of catheters, especially in the first six weeks of the study and only four of the randomised catheter patients completed the full 26 weeks of the study. However, eight of the pads patients were catheterised between the 7th and 22nd week because of deteriorating general condition and all retained their catheters for the remainder of the study period. Of 35 patients who had experienced catheters and pads, 12 expressed a clear preference for catheters, 12 for pads, and 11 were undecided. Nurses were in favour of the use of pads, mainly because of concerns about urinary infection with catheters. Comparing costs for patients managed with catheters (532 patient weeks) or pads (903 patient weeks), catheter patients required less nursing time (15.4 v 29.0 h per patient per week) but equipment costs were higher (19.20-24.65 pounds v 8.79-11.35 pounds per patient per week), mainly because of the cost of catheter care (12.75 pounds per patient per week). Asymptomatic bacteriuria was prevalent in both groups but 73% of catheterised patients received treatment for clinical signs of infection compared with 40% of pads patients. Only 30% of patients who were treated had any generalised symptoms of infection. CONCLUSIONS: Use of catheters reduces nursing time but may increase weekly equipment costs depending on the cost of laundry. Despite the high dropout rate among patients randomised to catheters a minority of patients (12/35) expressed a clear preference for catheters and we believe that more patients with intractable incontinence should be given a trial of catheterisation to assess acceptability. Bacteriuria was prevalent in pads or catheter patients but no major episodes of invasive infection were noted in either group.

Aged↗
PubMed1991

Reduction (dethiolation) of protein mixed-disulfides; distribution and specificity of dethiolating enzymes and N,N'-bis(2-chlorethyl)-N-nitrosourea inhibition of an NADPH-dependent cardiac dethiolase.

The S-thiolated proteins phosphorylase b (Phb) and carbonic anhydrase III (CAIII) were prepared with [3H]glutathione in a reaction initiated with diamide. These substrates were used to measure the rate of reduction (dethiolation) of protein mixed-disulfides by enzymes with properties similar to those of thioredoxin and glutaredoxin. This enzyme activity is termed a dethiolase since the identities of the enzymes are still unknown. The dethiolation of either S-[3H]glutathiolated Phb or S-[3H]glutathiolated CAIII was employed in tissue assays and for study of two partially purified dethiolases from cardiac tissue. NADPH-dependent dethiolase activity was most abundant except in rat liver and muscle. Total dethiolase activity was approximately 10-fold higher in neutrophils, 3T3-L1 cells, and Escherichia coli than in other sources. Rat skeletal muscle had 3- to 4-fold higher dethiolase activity than rat heart or liver. These data indicate that protein dethiolase activity is ubiquitous and that normal expression of the two dethiolase activities varies considerably. A partially purified cardiac NADPH-dependent dethiolase acted on Phb approximately 1.5 times faster than CAIII, and a glutathione (GSH)-dependent dethiolase acted on Phb 3 times faster than CAIII. The Km for glutathione for the GSH-dependent dethiolase was 15 microM with Phb as substrate and 10 microM with CAIII. Thus, the GSH-dependent dethiolase is probably not affected by normal changes in the cardiac glutathione content (normally approximately 3 mM). Partially purified cardiac NADPH-dependent dethiolase was inactivated by BCNU (N,N'-bis(2-chloroethyl)-N-nitrosourea) and the GSH-dependent dethiolase was unaffected under similar conditions. In a soluble extract from bovine heart, 200 microM BCNU inhibited NADPH-dependent dethiolase by more than 60% but did not affect GSH-dependent activity. These results demonstrate that BCNU is a selective inhibitor of the NADPH-dependent dethiolase.

Animals↗
PubMed1991

Influenza type A and B infections in hospitalized pediatric patients. Who should be immunized?

Medical records of 99 hospitalized pediatric patients whose respiratory viral cultures yielded influenza type A or B during the winter of 1988/1989 were reviewed. We compared the records of patients considered to be at high risk (n = 43) with those of patients considered to be at low risk (n = 56) to determine differences in morbidity and mortality and if vaccination was warranted. Sixty-six percent of high-risk patients had chronic pulmonary disease. Forty-four percent of the high-risk and 11% of the low-risk patients were hospitalized for 14 or more days. Nosocomial influenza infections were identified in 14% of the high-risk and 4% of the low-risk patients. Four of the high-risk patients and only one of the low-risk patients were intubated. Of the three deaths, two occurred in the high-risk group. None of the high-risk patients who experienced significant morbidity had been immunized. We need to immunize high-risk patients, particularly high-risk pulmonary patients.

Cross Infection↗
PubMed1991

Predicting schizophrenia outcome with self-report measures of family interaction.

This study is based on 18 patients admitted to a psychiatric hospital with a DSM-III-R diagnosis of schizophrenia who currently were living with one or both parents. Patients and parents completed several questionnaire, including the Parental Bonding Index (PBI), the Family Environment Scale (FES), the Hostility and Direction of Hostility Questionnaire (HDHQ), and the Brief Symptoms Inventory. Observer ratings of patients' symptoms also were made. Outcome was predicted best by patients' ratings of mothers on the PBI and by mothers' scores on the HDHQ Criticism of Others scale. Other significant outcome predictors were the number of previous admissions to hospital, patients' scores on the HDHQ Projected Hostility scale and the FES Expressiveness scale, and fathers' scores on the FES Achievement-Orientation scale.

Adolescent↗
PubMed1991

The yield of barium enema in patients undergoing inguinal hernia repair or abdominal hysterectomy.

It is the practice of some gynecologists and general surgeons to preoperatively evaluate the colon with a barium enema (BE) examination to exclude potential intestinal involvement or coexistent disease in patients undergoing pelvic or hernia operations. This practice appears to be based on anecdotal data with few studies specifically evaluating its usefulness. We retrospectively evaluated the records of 190 patients at William Beaumont Army Medical Center during 1986 to 1987 who received a preoperative BE prior to total abdominal hysterectomy (TAH) or inguinal hernia repair (IHR). The tumor registry charts of 59 patients diagnosed with carcinoma of the colon and rectum during the same period were also cross-checked to determine if any were detected during preoperative evaluation for TAH or IHR. BE findings were considered significant if they altered surgical management or asymptomatic carcinoma was detected. Of 86 patients screened before TAH by BE, eight had abnormal findings with subsequent colonoscopy revealing four with adenomatous polyps, one of which required surgical resection. Of 104 patients screened before IHR by BE, 15 had abnormal findings with subsequent colonoscopy revealing five patients with adenomatous polyps and two with adenocarcinoma. Screening preoperative BE had a low yield of clinically significant findings, which was even lower in the subgroup with carcinoma. There was no apparent relationship between findings and age in our study. Our results suggest that the use of routine preoperative BE has a low yield and should be performed only if clinical symptoms or findings suggest a need for this study.

Adult↗