Biomedical subjects
Publications and source records attributed to C W Koch.
A survey of present opinions on the safety of diagnostic ultrasound applications is presented together with some data on output levels. Physical mechanisms involved in potential adverse effects are described. Labelling requirements of the equipment are defined and specified. These requirements are contained in a recent proposal of the Netherlands' Committee on the Safety of Ultrasound.
The influence of liver volume and cigarette smoking on antipyrine clearance and metabolite formation was studied in seventeen volunteers (eight smokers, nine non-smokers). Inter-test coefficient of variation of liver volume (as determined by ultrasound) was 6.3%. The mean antipyrine clearance was 49.3 +/- 18.3 ml min-1 and when normalized for liver volume 36.1 +/- 10.1 ml min-1 l-1. The antipyrine clearance per unit volume of liver was significantly higher in smokers (43.0 +/- 10.5 ml min-1 l-1), than in non-smokers (30.0 +/- 4.6 ml min-1 l-1) (P less than 0.01). No significant difference was found between the two groups as to the excreted amounts of 4-hydroxyantipyrine (OHA), norantipyrine (NORA), and 3-hydroxymethylantipyrine (HMA). Normalized for liver volume the mean clearances for production (Clm) of these metabolites were significantly higher in the group of smokers than in the group of non-smokers. The greatest change was observed for OHA formation. However, analysis of variance showed that the differences in the percentages of change of the mean Clm of these metabolites in the two groups are not significant.
Sonograms of 45 consecutive patients with histologically proven acute cholecystitis were retrospectively reviewed. The following sonographic criteria were evaluated for the presence of: thickening of the gallbladder wall; enlargement of the transverse diameter; gallbladder pressure pain (Murphy's sign); local hypoechoic areas in the bladder wall, and finally the indistinct internal appearance. All 4 patients (8.9%) with acalculous cholecystitis were detected by ultrasound. Its sensitivity as a test to detect acute cholecystitis is 88.9%, its specificity and accuracy 97.8 and 96.1%, respectively.
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The effect of liver cirrhosis on plasma clearance and metabolite profile of i.v. administered antipyrine was studied in 23 patients with alcoholic liver cirrhosis (age 37-70 years) and 17 healthy subjects (age 28-55 years). Liver volume was also measured and was found to be larger in patients than in controls, mean values being 1.86 and 1.36 l respectively. The elimination half-life of antipyrine in patients with alcoholic liver cirrhosis was significantly longer than in the healthy subjects (P less than 0.001). Mean values were 39.9 and 10.1 h respectively. Alcoholic liver cirrhosis had no effect on the apparent volume of distribution of antipyrine, but antipyrine plasma clearance was substantially reduced in the patients. Mean clearance values (ranges) were 13.5 (9.3-22.8) ml/min in the patients and 49.3 (31.1-103) ml/min in healthy subjects. Normalization of antipyrine plasma clearance for liver volume resulted in an only slightly increased distinction between patients and healthy subjects, mean values (ranges) being 7.8 (3.3-13.0) ml min(-1) 1(-1) and 36.1 (21.9-35.9) ml min(-1) 1(-1) respectively. The cumulative renal excretion of 4-hydroxyantipyrine (OHA) and norantipyrine (NORA) was significantly lower in patients with alcoholic liver cirrhosis than in healthy subjects, as was the total recovery of antipyrine and major metabolites from urine. Mean values were 15.0, 8.4 and 41.2% of dose in the patients respectively and 24.3, 25.8 and 68.9% of dose in the control subjects. Excreted amounts of total and unconjugated 3-hydroxymethylantipyrine (HMA) and of unchanged antipyrine were the same in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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A study was performed to assess the reliability and sensitivity of ultrasound for the screening of asymptomatic children of patients with known adult polycystic kidney disease (APKD) and to compare this technique with the IVP and conventional laboratory techniques. Ultrasound appears to be at least as sensitive as IVP for identifying carriers of the gene for polycystic kidney disease. The identification of about 50% of a group of 21 asymptomatic individuals-at-risk in the 21-30-year age group as gene carriers, both with ultrasound and IVP, is promising for the early detection of this disease and therefore for genetic counselling in the future. This is the first step toward the construction of an age-specific detection curve for gene carriers, which is necessary in order to be able to calculate the probability that symptomatic subjects-at-risk carry the APKD gene.
Ultrasonic and scintigraphic examination of the liver took place in 148 patients. 29 had normal livers, 36 had cirrhosis, 11 had obstructive jaundice, 12 had fatty livers, 60 had focal liver defects. In case of diffuse liver disease the accuracy of both methods is about the same except for fatty liver which is poorly diagnosed by scintigraphy. Focal liver disease is determined with a relative high percentage false-negative for scintigraphy and a relative high percentage false-positive for echography. It is recognized that previous knowledge of the scintigraphic result may raise the accuracy of ultrasound examination of the liver. As echography could distinguish cystic from solid lesions both methods of liver imaging are considered complementary.
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