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Biomedical subjects

A Norman

Publications and source records attributed to A Norman.

14 recordsLinked to original sources
PubMed1979

Serum bile acids after a test meal in Crohn's disease.

The serum levels of conjugated cholic and chenodeoxycholic acid have been studied before and during a 4 h period after the intake of a liquid test meal in seven control subjects and in fourteen patients with Crohn's disease. The concentrations of serum bile acids were determined by radioimmunoassay. The control group showed a postprandial increase of both conjugates with a return to the fasting level for cholic acid within 4 h. The chenodeoxycholic acid conjugate did not return to the fasting level within the test period. The serum bile acid concentration in Crohn's disease divided the patients in two groups; one group with decreased or normal fasting levels and low postprandial increase and another group with elevated fasting levels and a postprandial increase without return to the fasting levels within the test period.

Adolescent↗
PubMed1979

Polarization of fluorescein fluorescence in single cells.

Measurement of fluorescence polarization (P) gives information about the immediate environment of the fluorescent molecule. We used a flow polarimeter to investigate the factors influencing P of fluorescein in mammalian cells to determine whether such measurements are useful for characterizing heterogeneous cell populations. Fluorescein was introduced into cells by incubation with FDA. Measurements of the intensity of fluorescence (TI) and polarization (P) revealed an unexpected dependence: P decreased with increasing intensity of fluorescence. This may be accounted for by the classical model of the binding of small molecules to protein in which P is dependent on the ratio bound to unbound molecules. We have been able to estimate the quenching due to binding and construct a Scatchard plot. We estimated a wavelength shift from in vitro data consistent with the dependence of P on wavelength seen in our cell work. Generally, the distributions of P are symmetrical. Photon statistics broadens the P distribution of dim cells. However, structure does develop in the P distribution when the cells are deprived of calcium or incubated in the cold. This appears as a shoulder on the P distribution or resolves into two peaks. Calcium deprivation may differentially affect a subpopulation of cells whose significance remains to be explored in various cell types.

Animals↗
PubMed1978

Spontaneous osteonecrosis of the knee and medial meniscal tears.

Several factors may play a role in the etiology of "spontaneous" osteonecrosis of the medial femoral condyle. Corticosteroids are known to induce osteonecrosis, and 45% of the patients in this study received steroids parenterally or by intra-articular injection. Another factor, heretofore given little attention, is the association of medial meniscal tears and "spontaneous" osteonecrosis. Twenty-one (78%) of 27 knees examined by arthrography demonstrated meniscal tears. Stress concentration over the edge of the meniscal fragment may result in ischemic necrosis of the femoral condyle. Early detection of a medial meniscal tear by arthrography in older patients and prompt treatment may be important in avoiding the late changes of "spontaneous" osteonecrosis.

Adolescent↗
PubMed1978

The clinical estimation of acute myocardial infarct size with 99mTechnetium pyrophosphate scintigraphy.

We evaluated scintigraphic techniques in estimating infarct size. In 26 patients with acute transmural myocardial infarction, 99mTechnetium pyrophosphate (TcPYP) infarct scintigraphy, gated cardiac blood pool scintigraphy and 201-Thallium (201-Tl) perfusion scintigraphy were performed. Invasive hemodynamic measurements were obtained and serial venous blood specimens taken for measurement of total and MB creatine phosphokinase (CPK). In farct size was estimated from the area of abnormal TcPYP uptake, the extent of reduced 201-Tl uptake, the percentage of abnormally contracting segments, and serial enzyme measurements. Left ventricular ejection fraction (LVEF) and stroke work index (LVSWI) were calculated. TcPYP infarct area was associated with the extent of reduced 201-Tl uptake (r = 0.66), the percentage of abnormally contracting segments (r = 0.64), and with both LVSWI (r = 0.73) and LVEF (r = 0.58). TcPYP infarct area did not correlate with cumulative total or MB-CPK release or the integrated total CPK-time curve, nor did the enzyme estimates of infarct size correlate with LVSWI or LVEF. Variable perfusion of infarcts of different sizes may explain the lack of correlation between TcPYP infarct area and enzyme estimates of infarct size. A combination of anatomic and functional indices derived from scintigraphic and hemodynamic measurements may provide the best assessment of infarct size.

Acute Disease↗
PubMed1978

Effect of therapy with methylprednisolone on the size of myocardial infarcts in man.

The use of steroids to decrease the size of the infarct and the mortality in patients with acute myocardial infarction has long been the subject of controversy. In the present study, two large doses of methylprednisolone were administered intravenously to 14 patients with relatively uncomplicated myocardial infarction within 17 hours after the onset of symptoms, whereas a comparable group of 15 patients with myocardial infarction served as controls. The size of the infarct was assessed utilizing serial measurements of serum levels of creatine phosphokinase and its myocardial isoenzyme, the MB form of creatine phosphokinase. There was no significant difference between the two groups of patients with regard to peak cumulative levels of total creatine phosphokinase and the MB form of creatine phosphokinase. Similarly, there was no difference between the two groups in mortality or in the incidence of malignant ventricular arrhythmias, atrioventricular block, congestive heart failure, or extensions of the infarct. We conclude that high intravenous doses of steroids given early in the course of myocardial infarction have neither deleterious nor beneficial effects.

Adrenal Cortex Hormones↗
PubMed1978

Gross hematuria: a complication of intrapelvic cement intrusion in total hip replacement.

Four patients with gross hematuria and dysuria following intrusion of methylmethacrylate into the pelvic cavity after total hip replacement are described. This is a rare, benign complication which generally occurs 7-14 days after surgery and subsides promptly with symptomatic treatment. The diagnosis can be made on a simple radiography of the pelvis which shows the radiopaque cement as a mass intruding with the pelvic cavity. On the urogram it frequently abuts against or produces an extrinsic impression on the urinary bladder. This complication is very likely a result of the exothermal reaction during polymerization of the methylmethacrylate.

Aged↗
PubMed1977

Flow system fluorescence polarization measurements on fluorescein diacetate-stained EL4 cells.

We have adapted a multiparameter cell sorter to measure the distribution of fluorescence polarization in cell populations. Measurements carried out on EL4 cells show that the percent polarization of fluorescein fluorescence decreases with increasing fluorescence intensity. This inverse relationship between polarization and intensity is shown both within the cell population and by the average values of the two quantities during both the increase and decrease of fluorescence intensity. The quantitative relation between intensity and polarization is different in hypertonic than in isotonic media. These results suggest that polarization measurements carried out at a fixed time after incubation of cells with fluorescein diacetate, which is converted to fluorescein within the cells, may depend in part on the rate of fluorescein accumulation, and that agents that have been reported to change the polarization of fluorescein in living cells may do so by changing the kinetics of fluorescein accumulation.

Cell Line↗
PubMed1977

"Tooth" sign in patellar degenerative disease.

In the total examination of the knee, degenerative changes and ossification in the quadriceps tendon easily recognized on the lateral roentgenogram may cause confusion in diagnosis when seen on the axial view. Vertical ridging of the osteophytes at the patellar insertion of the quadriceps tendon can resemble dentate structure ("tooth" sign). Two hundred and fifty examinations of the knee in different age groups were reviewed and several anatomical sections of the quadriceps-patella insertion were studied. The "tooth" sign represents the relief of severe osteophyte formation in the bundle of the quadriceps tendon at its insertion into the patella.

Adolescent↗
PubMed1976

Studies on human monocytes with a multiparameter cell sorter.

Suspensions of human lymphocytes and monocytes separated by the Ficoll-hypaque method from the peripheral blood show a Coulter volume distribution, measured with a multiparameter cell sorter, characterized by a minor peak at 500 mu3, containing 5-15% of the cells, and a major peak at 200 mu3. Using fluorescent latex particles we have found that the monocytes, the cells that ingest the latex particles, all lie in the 500 mu3 peak; conversely, all of the cells in the 500 mu3 peak are monocytes. When the cell suspensions are incubated, the monocytes increase both the average volume and in absolute numbers. The number of monocytes approximately doubles during 3 days of incubation, when it reaches its maximum value. At that time we have found that all of the monocytes lack receptors for sheep red blood cells and all possess receptors for human gamma-globulin. The increase in monocyte number appears, therefore, to arise from the enlargement of "monocyte presursors" that resemble lymphocytes in volume and resemble both the monocytes and the B lyphocytes with respect to surface sheep red blood cell and human gamma-globulin receptors.

Animals↗
PubMedDate not supplied

Absorbed dose in the presence of contrast agents during pediatric cardiac catheterization.

Administration of x-ray contrast agents during heart catheterization examination increases the absorbed radiation dose in tissue. To estimate the dose absorbed by the blood of children undergoing diagnostic heart catheterization and angiocardiography, a number of measurements and calculations were conducted. First, entrance and exit exposures to the patient were measured with thermoluminescent dosimeters calibrated for the diagnostic x-ray energy range. Second, a dose enhancement factor was calculated from mass energy absorption coefficients for various concentrations of the contrast media and at selected x-ray energies. Third, the dose enhancement factor was estimated from survival of peripheral blood lymphocytes suspended in varying concentrations of the contrast agent during exposure to graded doses of x-rays. Fourth, a mean absorbed dose to the patient's blood was calculated using (a) the dose enhancement factor determined above, (b) an estimate of the mean exposure in the irradiated body volume calculated from the entrance and exit exposure measurements, (c) an effective iodine concentration in the blood during the exposure time, and (d) a ratio correcting for the distribution and circulation of the blood. For eight pediatric patients monitored, absorbed doses to the blood ranged between 3 and 12 rad. These values were two to three times greater than the expected dose without administration of a contrast agent.

Angiocardiography↗