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Biomedical subjects

R E Miller

Publications and source records attributed to R E Miller.

At least 253 records · Page 14Linked to original sources
PubMed1977

Colonic polyp detection: role of roentgenography and colonoscopy.

In order to determine the relative yields of colonoscopic and radiologic examinations of the colon, the following guidelines are suggested: (a) prospective data collection; (b) a standard, effective colon cleansing regimen; (c) colonoscopic and radiologic examiners of comparable expertise; (d) examiners should be unaware of each other's findings; (e) a suitable method for demonstrating false-negative findings and for resolving conflicting findings between the two examinations; and (f) indexing of the study findings as to lesion size, lesion location, quality of colon cleansing, and examiner's level of confidence. The two examinations should be used as complementary diagnostic procedures.

Colon↗
PubMed1977

View box exercises for teaching problem solving in radiology.

An organized radiologic problem-solving system is presented for developing improved view box exercises for students and residents. It is based on six components: (1) problem sensing, (2) problem hypothesizing, (3) problem searching and definition, (4) problem identification, (5) resolution, and (6) verification. Since all examinations by the practicing radiologist involve these components, worthwhile simulated clinical management games should also incorporate them. A simulated radiologic exercise should be a valid measurement of the resident's ability to manage a wide range of clinical situations and techniques and should improve problem-solving strategies. Use of simulated clinical cases eliminates risk to patients during the educational process.

Audiovisual Aids↗
PubMed1976

Delta-9-THC and nonverbal communication in monkeys.

Male rhesus monkeys were trained to perform an instrumental avoidance conditioned response. They were then paired in the "cooperative conditioning" paradigm, a situation designed to measure the quality of nonverbal communication by changes in facial expression. A "responder monkey" was able to perform discriminated instrumental avoidance responses by processing facial expressive cues provided through a closed circuit television picture of a "stimulus monkey" which was receiving presentations of the conditioned stimulus. Oral administration of 1.0 mg/kg of delta-9-tetrahydrocannabinol (delta-9-THC) to the stimulus animal, the responder, both animals, or neither animal was given in all possible combinations of pairings to determine if delta-9-THC affects the expressiveness of the stimulus monkey or the sensitivity of the responder to the expressions of others. The drug impaired the display of facial expression in "stimulus" subjects but enhanced the ability of "responders" to discriminate the expressions of their partners. Measures of heart rate during cooperative conditioning revealed that delta-9-THC lowered cardiac rates of responder monkeys.

Animal Communication↗
PubMed1976

Direct neural inhibition of insulin secretion in response to systemic hypoglycemia.

The innervated pancreas of an anesthetized small "pancreas" dog was cross-perfused with blood from a large "support" dog in order to separate neural from blood-borne influences on the immunoreactive insulin secretion rate (ISR). The arterial plasma reducing sugar (sugar) concentration could be varied independently in the pancreas dog systemic circulation and in its pancreas. After tying of the hepatic arteries and portal vein in the pancreas dog, its systemic arterial plasma sugar concentration was allowed to fall in 10 experiments. This was prevented in five control experiments by intravenous glucose infusion (7 mg/kg-min). In all experiments, pancreatic arterial plasma sugar concentration was sustained, and at 40 min it was elevated 50 mg/100 ml by glucose infusion into the pancreatic blood supply. Bilateral splanchnic nerve section at 120 min caused an increase of the ISR in all experiments, but a greater rise occurred from the pancreases of the 10 dogs allowed to become hypoglycemic (P less than .02). In two further experiments, the splanchnic nerves were not cut, and no rise in ISR occurred. In conclusion, systemic hypoglycemia can inhibit insulin secretion by means of the splanchnic nerves.

Animals↗
PubMed1976

Optimal visualization of esophageal varices.

Twelve patients with known esophageal varices and willingness to cooperate were included in the study. Medications administered were placebo, 2 mg of glucagon, and 30 mg of propantheline bromide. All medications were given double-blind and crossover. On the basis of this study the authors believe that for optimal visualization of esophageal varices the following is the procedure of choice: (1) the patient should remain horizontal (this is best done in the left lateral position for comfort and ease of expectoration) for ten minutes after swallowing high density barium; (2) the patient should "clear his throat" frequently and expectorate all saliva (barium sticks to the pharynx and makes the patient want to swallow and "clearing his throat" by forced expiration helps the patient to expectorate this coating and prevents swallowing); (3) filming should be done in expiration in the supine (left posterior oblique to table top) position; and (4) in equivocal cases the examination can be repeated with an anticholinergic drug if the patient has no contraindications to its use. The patient should empty his bladder just before administration of the drug. The intelligent use of these factors should result in a saving of both fluoroscopic time and film, and give the radiologist a safe optimal diagnostic yield.

Adult↗
PubMed1976

The clean colon.

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Barium Sulfate↗
PubMed1976

Evaluation of a multitest microtechnique for yeast identification.

A new, multitest, microtechnique system, API 20C (Analytab Products Inc. Clinical Yeast System), was evaluated by comparing it to the U.S. Center for Disease Control (CDC) standard techniques for the identification of yeast. Forty-four yeast strains isolated from clinical specimens were tested by fermentation and assimilation. Six fermentation carbohydrates and ten assimilation carbohydrates were compared. API results were read after incubation of 24 and 48 hours while the standard CDC system was read after 48 hours and 14 days when needed. One hundred per cent agreement in identification was found between the two systems in the strains studied. Growth in the presence of actidione was tested by the API strip only and gave unreliable results with nine per cent of the strains tested. The API 20 Clinical Yeast System provides a reliable and rapid approach to yeast identification enabling the clinical laboratory to completely identify a yeast organism in 48 hours instead of the usual four to 14 days. A cost comparison showed the API system to be significantly more economical than the conventional method of identification.

Culture Media↗
PubMed1975

Enzymes regulating glycogen metabolism in swine subcutaneous adipose tissue. I. Phosphorylase and phosphorylase phosphatase.

Glycogen phosphorylase from swine adipose tissue was purified nearly 700-fold using ethanol precipitation, DEAE-cellulose adsorption, AMP-agarose affinity chromatography, and agarose gel filtration. The purified enzyme migrated as one major and several minor components during polyacrylamide gel electrophoresis. Activity was associated with the major component and at least one of the minor components. The molecular weight of the disaggregated, reduced, and alkylated enzyme, estimated by polyacrylamide gel electrophoresis performed in the presence of sodium dodecyl sulfate, was 90,000. Stability of the purified enzyme was considerably increased in the presence of AMP. The isoelectric pH of the enzyme in crude homogenates was 6.3. The sedimentation coefficient of the purified enzyme (7.9 S) and that in crude homogenates (7.3 S) was determined by sucrose density gradient sedimentation. Optimal pH for activity was between pH 6.5 and 7.1. Apparent Km values for glycogen and inorganic phosphate were 0.9 mg/ml and 6.6 mM, respectively. The Ka for AMP was 0.21 mM. Enzyme activity was increased by K2SO4, KF, KCl, and MgCl2 and decreased by NaCl, Na2SO4, D-glucose, and ATP. Inhibition by glucose was noncompetitive with the activator AMP; inhibition by ATP was partially competitive with AMP. The purified enzyme was activated by incubation with skeletal muscle phosphorylase kinase. Enzyme in crude homogenates was activated by the addition of MgCl2 and ATP; activation was not blocked by addition of protein kinase inhibitor, suggesting that phosphorylase kinase in homogenates of swine adipose tissue is present largely in an activated form. Deactivation of phosphorylase a by phosphorylase phosphatase was studied using enzyme purified approximately 200-fold from swine adipose tissue by ethanol precipitation, DEAE-cellulose chromatography, and gel filtration. The Km of the adipose tissue phosphatase for skeletal muscle phosphorylase a was 6 muM. The purified swine adipose tissue phosphorylase, labeled with 32-P, was inactivated and dephosphorylated by the adipose tissue phosphatase. Dephosphorylation of both skeletal muscle and adipose tissue substrates was inhibited by AMP and glucose reversed this inhibition. Several lines of evidence suggest that AMP inhibition was due to an action on the substrate rather than on the enzyme. We have previously reported that the system for phosphorylase activation in rat fat cells differs in some important characteristics from that in skeletal muscle. However, both swine fat phosphorylase and phosphorylase phosphatase have major properties very similar to those described for the enzymes from skeletal muscle.

Adenosine Monophosphate↗
PubMed1975

Enzymes regulating glycogen metabolism in swine subcutaneous adipose tissue. II. Glycogen synthase.

Glycogen synthase from swine adipose tissue was purified to apparent homogeneity using ethanol precipitation, DEAE chromatography, and affinity chromatography utilizing glucosamine 6-phosphate as the ligand. The purified enzyme migrated as a single protein component during electrophoresis on polyacrylamide gels at pH 7.3 although some protein failed to enter the running gel. Enzyme incubated with sodium dodecyl sulfate (SDS) migrated as one component (mol wt similar to 90,000) on SDS-polyacrylamide gel electrophoresis. The enzyme was relatively unstable at all stages of the purification procedure, but stability was increased in the presence of glucose 6-phosphate, UDPG, or glycerol. The isoelectric point of the purified enzyme and of enzyme activity in crude homogenates was pH 4.8. The sedimentation coefficient of the enzyme in crude homogenates was 8.5 S. The pH-activity profile showed an optimum at pH 7.8 in the absence of glucose 6-phosphate but no definable optimum between pH 7.0 and 9.2 in its presence. The Km of glycogen synthase I for UDPG was 250 muM in the absence and 37 muM in the presence of glucose 6-phosphate; the K-a for glucose 6-phosphate was 18 mu-M. The K-m of glycogen synthase D for UDPG was 130 mu-M in the presence of glucose 6-phosphate; the Ka for glucose 6-phosphate was 1 mM. The anions sulfate and phosphate activated the enzyme when assays were performed in the absence of glucose 6-phosphate. Fluoride produced activation of enzyme assayed either in the presence or in the absence of glucose 6-phosphate.

Adipose Tissue↗
PubMed1975

Bronchial adenoma.

Thirty-three patients with bronchial adenoma have been treated in U.S. Army hospitals. These included 27 with carcinoid, 3 with mucoepidermoid carcinoma, and 3 with adenoid cystic carcinoma. No deaths could be directly related to the adenomas during an average follow-up of 14.5 years.

Adenoma↗
PubMed1975

The precision of a special purpose analog computer in clinical cardiac output determination.

Three hundred dye-dilution curves taken during our first year of clinical experience with the Waters CO-4 cardiac output computer were analyzed to estimate the errors involved in its use. Provided that calibration is accurate and 5.0 mg of dye are injected for each curve, then the percentage standard deviation of measurement using this computer is about 8.7%. Included in this are the errors inherent in the computer, errors due to baseline drift, errors in the injection of dye and acutal variation of cardiac output over a series of successive determinations. The size of this error is comparable to that involved in manual calculation. The mean value of five successive curves will be within 10% of the real value in 99 cases out of 100. Advances in methodology and equipment are discussed which make calibration simpler and more accurate, and which should also improve the quality of computer determination. A list of suggestions is given to minimize the errors involved in the clinical use of this equipment.

Cardiac Output↗