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Biomedical subjects

J Melton

Publications and source records attributed to J Melton.

At least 19 recordsLinked to original sources
PubMed1993

Are patients with neoplasia at an increased risk for cardiac myxomas?

A case-control study was undertaken to assess whether a significant association exists between the presence of a neoplasm or malignancy and the presence of a cardiac myxoma. We identified 13 patients seen at our institution between 1935 and 1990 whose autopsies revealed a cardiac myxoma that was undetected during the patient's lifetime. For each patient four control subjects were selected among the autopsied patients who had never had a cardiac myxoma; these were matched for age at death, gender, and year of autopsy. The institutional medical records and autopsy reports revealed that 46% of the patients and 65% of their controls had a neoplasm diagnosed prior to or at autopsy. The estimated odds ratio was 0.34 (95% confidence interval, 0.05 to 1.84). There was insufficient evidence to conclude that an association exists between the presence of a neoplasm and the presence of a cardiac myxoma (P = .2722).

Adult↗
PubMed1990

Injury surveillance in agriculture.

Information on agricultural trauma is limited and difficult to find. Planning for effective prevention strategies and evaluation is compromised by lack of a good surveillance system. Several agencies and organizations have provided some data. Although their summation is at best an approximation of the real situation, a critical review of current data bases is presented. The literature is also reviewed attempting to characterize agricultural trauma. This characterization was classified into: 1) case descriptions, 2) reviews of general articles on the hazards of farming, and 3) descriptive surveys of agricultural injuries. A summary of the available literature still leaves a rather superficial understanding of the entire injury picture. A new approach to surveillance is necessary to overcome past deficiencies. A combined modality approach is suggested, utilizing on-site survey, mail survey, telephone interviewing, and medical record verification. Trial applications of two such systems in Minnesota are described.

Accidents, Occupational↗
PubMed1990

Viral infections during pregnancy: a guide for the emergency physician.

Emergency physicians are frequently called on to treat or advise pregnant patients. When faced with a pregnant patient who has clinical evidence of or exposure to a viral illness, the emergency physician must be aware of the potential maternal and fetal risks posed by various viral agents. This review provides current, accurate information and guidance for the pregnant patient.

Emergency Medicine↗
PubMed1989

A patient questionnaire to identify bowel disease.

Although functional gastrointestinal symptoms are seen frequently by internists and are the commonest reason for patients to be referred to gastroenterologists, no validated self-report questionnaire is available for their diagnosis. To differentiate among non-ulcer dyspepsia, the irritable bowel syndrome, organic gastrointestinal disease, and health, we developed a self-report questionnaire. Our bowel disease questionnaire, which evaluated 46 symptom-related items was completed prospectively by 361 subjects before their clinical evaluation as outpatients. Of these subjects, 115 were categorized ultimately as having functional bowel disease (non-ulcer dyspepsia or the irritable bowel syndrome), 101 were categorized ultimately as having organic gastrointestinal disease, and 145 were healthy persons having routine periodic examinations for whom no additional diagnoses were made. All diagnoses were based on independent clinical evaluations, not on the patients' responses to the questionnaire. The bowel disease questionnaire was acceptable and easily completed; it elicited symptoms in a highly reliable manner and was shown to be a valid measure of functional bowel complaints. Our questionnaire discriminated non-ulcer dyspepsia from irritable bowel syndrome with a sensitivity of 75% and a specificity of 72%, and it discriminated functional bowel disease from organic disease and health with sensitivities of 85% and 83%, and specificities of 60% and 76%, respectively. We believe that this questionnaire is an additional and useful diagnostic tool for identifying patients with functional gastrointestinal symptoms.

Adolescent↗
PubMed1987

Viral hepatitis. A population-based study in Rochester, Minn, 1971-1980.

The incidence of acute viral hepatitis among Rochester, Minn, residents 1971-1980 was 28.6 per 100,000 person-years (p-y) (age- and sex-adjusted to the 1980 white population in the United States). The adjusted incidence of hepatitis B (12.9 per 100,000 p-y) was somewhat less than for hepatitis non-B (15.6 per 100,000 p-y). Each type was more frequent among young adults, especially males. The incidence of hepatitis was greater among those employed in the health service industry than among nonmedical employees (53.4 vs 20.0 per 100,000 p-y). Medical employees had nearly a fivefold increased incidence of hepatitis B and a twofold increased incidence of hepatitis non-B. Exposure to known hepatitis cases was common, but other possible causative factors were not frequent. In this midwestern community, the incidence of acute viral hepatitis is substantial, with medical employees at significantly increased risk.

Adolescent↗
PubMed1986

Effect of lidocaine and bretylium on energy requirements for transthoracic defibrillation: experimental studies.

The purpose of this study was to determine the effect of the antiarrhythmic drugs lidocaine and bretylium on the minimal energy requirement for transthoracic defibrillation--the defibrillation threshold. Closed chest dogs were anesthetized with chloralose or pentobarbital; lidocaine was administered at varying rates for 2 hours and defibrillation threshold periodically redetermined. Similar protocols were followed for bretylium. Serum lidocaine levels from therapeutic to toxic ranges were obtained, and up to a 60% (p less than 0.05) increase in defibrillation threshold in the pentobarbital-anesthetized dogs was demonstrated. In chloralose-anesthetized dogs the lidocaine effect was modest, with only a 10 to 20% rise in defibrillation threshold (p = NS) despite similar increases in serum lidocaine levels. Thus, lidocaine increases the minimal energy requirements for transthoracic defibrillation, but this effect is in part anesthesia-related, indicating a lidocaine-pentobarbital interaction. When phentolamine was administered to chloralose-anesthetized dogs receiving lidocaine, defibrillation threshold rose 13% (p less than 0.05); this suggests that alpha-adrenergic receptor blockade is at least in part the mechanism of the pentobarbital-lidocaine interaction on defibrillation threshold. Bretylium with either anesthetic had no significant effect on defibrillation threshold.

Animals↗
PubMed1986

Trigeminal herpes zoster causing mandibular osteonecrosis and spontaneous tooth exfoliation.

We have described a 60-year-old woman with polymyalgia rheumatica treated initially with prednisone but ultimately with azathioprine and cyclophosphamide. Herpes zoster infection along the mandibular division of the right trigeminal nerve ensued with spontaneous exfoliation of two teeth. She subsequently died. Medical practitioners need to be made aware of this rare complication of a common disease.

Azathioprine↗
PubMed1985

Experimental evaluation and initial clinical application of new self-adhesive defibrillation electrodes.

We evaluated the efficacy of self-adhesive electrode pads for defibrillation and cardioversion in animals and patients. In 11 anesthetized dogs, the success rate of shocks given to terminate electrically-induced ventricular fibrillation was similar for both self-adhesive electrode pads and hand-held electrode paddles; success rate approached 100% at energies of 125-150 joules. Eighty patients undergoing defibrillation or elective cardioversion received shocks from self-adhesive pads. In all but 2 patients defibrillation or cardioversion was achieved at least once using these pads. The pads were equally effective from either apex-anterior or apex-posterior positions. The transthoracic impedance using self-adhesive pads was 75 +/- 21 ohms, similar to transthoracic impedance we previously reported when using standard hand-held paddles. No complications occurred with the use of the pads. We conclude that self-adhesive electrode pads are effective for defibrillation and cardioversion.

Animals↗
PubMed1985

Artifactual regional gray level variability in contrast-enhanced two-dimensional echocardiographic images: effect on measurement of the coronary perfusion bed.

The purpose of this study was to determine the extent of regional variability of image echocardiographic amplitude (expressed as gray level variability) in contrast-enhanced two-dimensional echocardiographic images, and to assess the effect of such baseline gray level variability on quantitation of the coronary perfusion bed. In 10 anesthetized closed chest dogs, short-axis papillary muscle echocardiographic images were obtained during control preinjection conditions and during injection of three contrast agents into the left main coronary artery with and without circumflex artery occlusion. Regional echocardiographic amplitude variation was measured by computer-based videodensitometric analysis of mean gray levels in four myocardial regions after cavity (background) gray level subtraction. To determine the effect of regional gray level variability on quantitation of the coronary perfusion bed, the contrast-enhanced left anterior descending artery perfusion bed was measured by two methods. The circumferential method ignored myocardial contrast inhomogeneity by measuring the circumferential extent of contrast enhancement, whether or not the enhancement by contrast medium extended transmurally. The exact method measured only the area of myocardium actually enhanced by contrast medium, which often did not extend transmurally. The perfusion beds determined by the two echocardiographic methods were compared with the anatomic perfusion bed determined by postmortem barium-gelatin coronary arteriography. Regional gray levels varied qualitatively and quantitatively in the control state (before contrast injection), with lateral regions being less bright than axial regions. After injection of contrast medium, brightness increased in all regions, the axial regions brightening most.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Echocardiographically detected dyskinesis, myocardial infarct size, and coronary risk region relationships in reperfused canine myocardium.

After permanent coronary artery occlusion, the extent of two-dimensional echocardiographically detected dyskinesis correlates well with infarct size. Reperfusion after coronary artery occlusion decreases infarct size; however, contractile function of myocardium salvaged in this way may remain depressed for several weeks. The purpose of this study was to explore the relationship between echocardiographically detected dyskinesis and infarct size in reperfused myocardium. We hypothesized that after transient coronary artery occlusion, the relationship between dyskinesis and infarct size would be altered because of the prolonged depression of contractile function after reperfusion so that dyskinesis would not predict infarct size. We also wanted to explore two related questions: (1) Does inotropic stimulation of reperfused myocardium result in improved systolic function in segments that are dysfunctional but not necrotic? (2) Does the relationship between infarct size and coronary risk region, which is linear in myocardium subjected to permanent coronary occlusion, remain linear in myocardium subjected to a sequence of occlusion and reperfusion? Thirty-seven sedated dogs with preplaced circumflex occluders underwent 1 or 2 hr of coronary artery occlusion, then 2 or 10 days of reperfusion. The percentage of the left ventricle that was dyskinetic was estimated from short-axis two-dimensional echocardiograms at the chordal and papillary muscle level obtained at control, after 1 or 2 hr of occlusion, after 20 min of reperfusion, and after 2 or 10 days of reperfusion. At 2 or 10 days of reperfusion, echocardiograms were also obtained during infusion of dobutamine. Area at risk was determined from postmortem barium-gelatin angiography and infarct size was determined at pathologic examination. We found a significant linear correlation between infarct size and risk region size in reperfused myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Self-adhesive preapplied electrode pads for defibrillation and cardioversion.

The efficacy of self-adhesive electrode pads for defibrillation and cardioversion was assessed in 80 patients who received 267 shocks from self-adhesive pads. In all but two patients, defibrillation or cardioversion was achieved at least once. The pads were equally effective when used in the apex-anterior or apex-posterior position. The transthoracic impedance using self-adhesive pads was 75 +/- 21 ohms (mean +/- standard deviation), which is similar to previously reported transthoracic impedance in defibrillation, using standard hand-held electrode paddles of 67 +/- 36 ohms. It is concluded that self-adhesive electrode pads are effective for defibrillation and cardioversion.

Arrhythmias, Cardiac↗
PubMed1983

Evaluation of a new defibrillation pathway--the tongue-epigastric route. I. Experimental studies in dogs.

The purpose of this study was to determine the efficacy of a tongue-epigastric defibrillation route in anesthetized dogs. Ventricular fibrillation was induced by rectangular pulses passed down a transvenous catheter into the right ventricle. Three groups of dogs were studied. Group I (15 dogs) received shocks from a 12 cm2 tongue electrode, a 50 cm2 circular, gelled self-adhesive electrode pad placed on the epigastrium and standard transthoracic defibrillator paddle electrodes. Shocks were given at energy levels of 50 to 460 joules (delivered energy, 50 ohm resistance). The success of the tongue-epigastric shocks in achieving defibrillation, and the resistance and current flow were determined at each energy level and compared with the same energy shocks from the standard transthoracic electrodes. In Group II (five dogs), comparisons were made between the 12 cm2 tongue electrode used in the first group of dogs and a larger tongue electrode of 40 cm2. In Group III (five dogs), intracardiac current flow (potential gradient) with tongue-epigastric and standard transthoracic electrodes was studied. In Group I, defibrillation success with the tongue-epigastric electrodes ranged from no success at 50 to 100 joules to 83% success at 460 joules. With standard transthoracic electrodes, success rates ranged from 65% at 50 joules to 100% at 300 joules. At all energies tested, the resistance was significantly higher and current significantly lower using tongue-epigastric compared with transthoracic electrodes. The higher tongue-epigastric resistance is probably related to the longer interelectrode distance; the correlation between interelectrode distance (x, in centimeters) and resistance (y, in ohms) in these dogs was y = 2.2x + 29.6, r = 0.78.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1980

Isolation and partial characterization of two human neurophysins: their use in the development of specific radioimmunoassays.

Two neurophysins (NPs) that are thought to be the primary protein forms produced with the hormones vasopressin (VP) and oxytocin (OT) were isolated from 5000 human pituitary glands. In sucrose gradient centrifugation of human neural lobes, each of these NPs had a distribution similar to that of either VP or OT. Such differential localization of 1 human NP (HNP) with VP and the other HNP with OT suggests an association of their biosynthesis, and it is on the basis of this association that 1 NP has been named VP-associated HNP (VP-HNP) and the other OT-associated HNP (OT-HNP). The purified proteins were complexed to bovine thyroglobulin in order to develop specific antisera. RIAs developed with these antisera are effective for each HNP in the range of 5-320 pg. Reference standards in both assays were corrected for protein content using amino acid analysis to obtain absolute protein concentration; this type of correction is recommended for all RIAs that measure proteins. The RIAs were used to measure the concentrations of HNPs in unextracted human plasma. In healthy, sitting, normally hydrated subjects of both sexes, VP-HNP and OT-HNP were, respectively, 73 +/- 5 and 382 +/- 30 pg/ml (mean +/- SEM; n = 20); there was no significant difference between values in males and females, provided the latter were not taking medication. Women on oral contraceptives had elevated (> 3 times normal) levels of OT-HNP but normal levels of VP-HNP. Eleven patients who had the syndrome of inappropriate secretion of antidiuretic hormone had elevated levels of VP-HNP but not necessarily of OT-HNP. Surgery was found to consistently increase plasma VP-HNP but not OT-HNP. In two of six subjects smoking caused a dramatic release of VP-HNP, as indexed by plasma levels which rose to more than 50 times the control values. One patient with lithium-induced nephrogenic diabetes insipidus had elevated plasma concentrations of both NPs. The sensitivity and specificity of the RIAs may make them useful clinically in certain pathological states.

Centrifugation, Density Gradient↗
PubMed1979

Comparative effects of delta 9-tetrahydrocannabinol, tetrabenazine and chlorpromazine on rectal temperature in the rat.

Tetrabenazine evoked a biphasic response in rectal temperature of the rat following intraperitoneal administration of 4.4--70.0 mg/kg. The initial hyperthermia was inversely related to the dose while the subsequent hypothermia was dose-dependent. This biphasic effect on temperature was similar to that seen with THC at 0.5 mg/kg, thus adding further evidence of a similarity in the mode of action of the two drugs. In contrast, only hypothermia was evident following chlorpromazine administration.

Animals↗