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Biomedical subjects

E U Buddemeyer

Publications and source records attributed to E U Buddemeyer.

14 recordsLinked to original sources
PubMed1992

Simultaneous measurements of glomerular filtration rate by two radioisotopic methods in patients without renal impairment.

Isotopic clearance techniques have been widely used to measure GFR but may give variable results depending on the level of renal function and the technique used. GFR, measured by the technique of plasma disappearance of 99mTc-labeled diethylenetriaminopentacetic acid ([99mTc]DTPA) was compared with simultaneously obtained urinary clearance of [99mTc]DTPA. GFR was also measured by concurrent 24-h clearance of creatinine. Forty-six measurements of GFR were obtained in 12 patients who had no evidence of renal disease. Plasma disappearance was measured from three timed plasma samples collected 60 to 180 min after the bolus injection of 200 microCi of [99mTc]DTPA and was calculated as the product of the volume of distribution (milliliters) at time zero and the clearance rate (per minute) as determined by the regression of the monoexponential plot. Urinary clearance was measured as the average of 3 1-h urinary clearances collected after a water diuresis was established. GFR measured by plasma disappearance was significantly greater (P less than 0.001) than GFR measured simultaneously by urinary clearance. There was a linear correlation between GFR measured by urinary clearance and that measured by plasma clearance (r = 0.994). Plasma clearance exceeded urinary clearance by a constant factor of 1.3 over the range studied (urinary clearance range, 49 to 94 mL/min/1.73 m2). It was concluded that at relatively a normal GFR, the plasma clearance of [99mTc]DTPA consistently overestimates the urinary clearance of [99mTc]DTPA.

Animals↗
PubMed1990

Acute effects of intravenous cyclosporine on blood pressure, renal hemodynamics, and urine prostaglandin production of healthy humans.

The acute renal failure associated with cyclosporine may result from vasoconstriction of intrarenal arterioles. To evaluate the mechanism of cyclosporine-induced nephrotoxicity, we acutely administered cyclosporine to eight healthy female volunteers with normal blood pressure and renal function. Cyclosporine (4 mg/kg) in 250 ml of 5% dextrose in water (D5W) was administered as a steady intravenous infusion over 6 hr. Glomerular filtration rate and renal plasma flow were measured by serum disappearance of 99m TcDTPA and 131I hippuran, respectively, during the last 3 hr of the infusion. D5W was given to the patients on separate days before the cyclosporine infusion to obtain control data. Systolic and diastolic blood pressure measured every hour during the infusions and renal vascular resistance were slightly higher during cyclosporine administration, but the increases were not statistically significant. Renal plasma flow was not affected by cyclosporine, being 479.6 +/- 24.9 ml/min during the control infusion and 463.3 +/- 12.7 ml/min during the cyclosporine infusion. However, glomerular filtration rate was reduced by cyclosporine in all patients (control, 108.8 +/- 2.5 ml/min, vs. cyclosporine, 91.1 +/- 2.2 ml/min, P less than .01), except one who demonstrated no significant change. Urinary excretion of thromboxane B2 during cyclosporine administration was markedly increased in all patients, being 39.9 +/- 8.2 ng/hr in the control period and 85.8 +/- 22.3 ng/hr during cyclosporine infusion (P less than .05), except for the one patient in whom no decrease in GFR was noted. There was no significant change in the urinary excretion rate for 6-keto-prostaglandin F1a or prostaglandin E during cyclosporine infusion. Serum averaged levels of peripheral renin activity, angiotensin II, and aldosterone did not change during with the cyclosporine administration compared with the control. All patients demonstrated a decrease in 24-h urinary excretion of sodium and potassium on the day of the cyclosporine infusion. Verapamil SR (240 mg daily for 7 days prior to cyclosporine infusion) did not reverse the reduction in glomerular filtration rate induced by cyclosporine; however, a significant reduction in renal vascular resistance and an increase in renal plasma flow (P less than .05) were noted when the volunteers were treated with both verapamil and cyclosporine compared with cyclosporine alone. Intravenous infusion of Cremophor EL, the vehicle to dissolve cyclosporine, demonstrated no significant effects on blood pressure, renal hemodynamics or urinary prostaglandin excretion.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

The value of retropharyngeal soft tissue measurements in trauma of the adult cervical spine. Cervical spine soft tissue measurements.

Widening of the retropharyngeal soft tissue space (RSTS) has been interpreted as a sign of cervical spine trauma. Widely differing measurements are reported in the literature. However it is clear that, using the currently acceptable limits of normal, a large number of patients without spinal injury are subjected to further tests. The RSTS on lateral cervical spine radiographs of 318 patients with a history of cervical spine trauma were measured at the C2-C4 level. The values for patients found to be normal or with fractures/dislocations were evaluated. Statistical analysis of the results demonstrates a considerable overlap in the RSTS of normal and abnormal patients. Therefore we suggest that RSTS measurements are of limited diagnostic value. Using the statistical probability of abnormality, guidelines that indicate which patients may require additional study are suggested.

Adult↗
PubMed1987

Value of chest radiography in excluding traumatic aortic rupture.

A retrospective review of chest radiographs from 205 patients with blunt chest trauma who also underwent aortography was performed. Forty-one of the 205 had aortographically proved aortic rupture. Discriminant analysis of 16 radiographic signs indicated that the most discriminating signs were loss of the aorticopulmonary window, abnormality of the aortic arch, rightward tracheal shift, and widening of the left paraspinal line without associated fracture. No single or combination of radiographic signs demonstrated sufficient sensitivity to indicate all cases of traumatic aortic rupture on plain chest radiographs without the performance of a large number of aortographically negative studies. The bedside anteroposterior "erect" view of the chest proved far more valuable than the supine view in detecting true-negative studies. Despite significant reader variability in the interpretation of the various radiographic signs, in general the analysis confirmed the role of chest radiography in this clinical situation, but suggests that its most beneficial use is in excluding the diagnosis and eliminating unwarranted aortography rather than in predicting aortic rupture.

Adolescent↗
PubMed1983

A nuclear medical manifestation of Munchausen's syndrome.

A man with an enlarged and tender left calf, chest pain, intermittant hemoptysis, and shortness of breath was referred for a lung scan. Positioning for the ventilation part of the study revealed a high level of radioactivity in the lungs, kidneys, bladder, colon, and salivary glands. The patient denied previous hospital studies and suggested that he may have become contaminated while transporting radioactive materials as an independent truck driver. He was found to be a classic example of Munchausen's syndrome.

Adult↗
PubMed1980

Modifications in biphasic liquid-scintillation vial system for radiometry.

Several modifications of the biphasic liquid-scintillation vial system for radiometry have been tried in order to improve the counting efficiency. The biphasic system consisted of an inner sterile vial containing medium and substrate, and an outer liquid-scintillation vial lined on the inside with filter paper impregnated with scintillation fluors and alkali. The system gave an overall counting efficiency of 14.6%. Substitution of methanolic NaOH for impregnation of the paper raised the counting efficiency to 29.1%. This could be further enhanced to 33.8% by lining only half of the outer vial with filter paper, thereby allowing improved optical transmission of scintillation light. Increasing the amount of fluor did not change the efficiency significantly. A complete interchange in the system, whereby half of the inner vial was lined with filter paper and was otherwise empty, while the outer vial contained the medium and substrate, gave the highest efficiency (36.9%). This also allowed the use of larger amounts of medium and the inoculum.

Carbon Dioxide↗
PubMed1978

Radiometric estimation of the replication time of bacteria in culture: an objective and precise approach to quantitative microbiology.

In a recently developed, two-compartment liquid scintillation vial, the evolution of 14CO2 resulting from bacterial metabolism of uniformly labeled d-glucose was measured sensitively, cumulatively, and automatically in a liquid-scintillation counter. In each of eight species tested, a period of log-linear expansion of cumulative counting rate with time was observed. The exponential increase in cumulative counting rate was related to cell replication time by the integral of a first-order differential equation. Within a given species, the replication time measured by radioassay was found to be remarkably constant, unaffected by a fourfold variation in the activity of added labeled d-glucose, insensitive to the presence of carrier dextrose, and independent of the number of bacteria in the initial inoculum over a range of five orders of magnitude. These experiments demonstrate that the replication rate of an organism in culture is a highly reproducible characteristic that is susceptible to precise radiometric measurement in fundamental units of time under a variety of experimental conditions.

Bacteria↗
PubMed1975

The physics of diagnostic ultrasound.

Sound waves progress through a medium at a velocity that is characteristic of that medium. In a particular medium, wavelength and frequency are inversely related, so that short wavelengths can only be obtained at higher frequencies. A beam of sound will not be directional unless the object that is sending (or reflecting) it is at least several times longer than the wavelength. In tissue directional beams of 1 cm or less in width can be produced at frequencies of 1 MHz or more. Other things being equal, the higher the frequency, the narrower the beam. The attenuation of beams of sound in tissue at ultrasonic frequencies is directly and almost linearly related to frequency in that the higher the frequency, the greater the attenuation and the weaker the return signals. In choosing an operating frequency for a particular purpose, one must therefore bear in mind that the advantages of the higher frequencies (i.e., better resolution, both in range and azimuth) are obtained at the bost of a shorter effective range. Accordingly, one makes the best compromise by selecting the highest frequency that permits a range adequate for the purpose. In scanning the abdomens of adults where the range may be fairly long, a 2 MHz transducer is used. For cardiac studies in pediatric patients where the range is shorter and the structures smaller, a 5 MHz probe can be used. In the globe of the eye the structures are minute, the medium one in which losses are quite low and the range is very short, permitting the use of frequencies in the 10 to 20 MHz range.

Acoustics↗
PubMed1974

Liquid scintillation vial for cumulative and continuous radiometric measurement of in vitro metabolism.

A two-compartment vial is described in which suspensions of bacteria, cells, or tissues may be cultured and their growth and metabolism measured radiometrically by using a liquid scintillation counter. The device consists of a scintillation vial lined with a cylinder of scintillating paper into which is placed a sterilized inner culture vial containing a carbon-14 substrate. The assembled device can be carried by the sample transport systems of conventional liquid scintillation counters. Evolved (14)CO(2) is collected and measured cumulatively and continuously. The device can be constructed simply and economically from readily available reagents and glassware. Data are given on relative sensitivity and on the effect of the color and transparency of the inner vial. A pilot experiment with bacteria (Escherichia coli) is described.

Carbon Dioxide↗
PubMed1974

Detection and localization of an occult vesicoenteric fistula.

Detection and localization of an enterovesicular fistula in a patient with chronic inflammatory bowel disease and recurrent urinary tract infection was accomplished by following a bolus of orally administered gold colloid as it traversed the gastrointestinal tract with serial scintiphotos and simultaneously monitoring the activity in the urine. When significant tracer was found in the urine, multiple scans of the abdomen were obtained to determine the location of the tracer. To confirm the site of the fistula, the tracer was mixed with barium and administered per rectum. Radiographs were obtained when significant activity was found in the urine. At surgery, bowel in the region of the cecum was adherent to the bladder, but no fistula was demonstrable by methylene blue instillation into the bladder. Postoperatively, the urinary tract infection cleared, and re-examination with oral Au198 colloid revealed no activity in the urine. The radiation dose to the gonads from this peocedure is 42 mrads. The procedure is safe, simple to perform, well tolerated, and permits an answer to the question of whether a fistula i present, and where it is located.

Abdomen↗