MRT of experimental liver abscesses: a comparison of a new blood pool contrast medium with gadolinium-DTPA in animal experiments

PURPOSE: In an experimental pyogenic liver abscess model, the signal intensities were compared intraindividually and interindividually after the application of a new blood pool contrast agent, 24-gadolinium-DTPA (diethylenetriamine-pentaacetic acid) cascade polymer, and after the application of gadopentetate dimeglumine. METHODS: In 20 rabbits with experimentally induced liver abscesses, the relative signal intensities of the liver, abscess centre, abscess wall and portal vein were assessed before and between 30 seconds and 60 minutes after injection of a 25 mumol/kg dose of gadolinium polymer and of 100 mumol/kg of gadolinium-DTPA, respectively. Measurements were performed at 1.5 Tesla, using a head coil and a Flash-2-D sequence. RESULTS: The interindividual comparison (unpaired T-test, p < 0.05) yielded significant differences of the relative signal intensities of the abscess centre (at any time point after contrast-media application), abscess wall (between 15 and 60 minutes after contrast media application), and portal vein (between 30 seconds and 7.5 minutes after contrast media application). The interindividual comparison showed a significantly higher abscess centre-liver contrast (between 30 seconds and 12.5 minutes after contrast media application) and a significantly higher abscess wall-centre contrast (between two and 7.5 minutes after contrast media application) after the application of gadolinium polymer compared with gadopentetate dimeglumine. CONCLUSION: In this animal model, the higher abscess centre-liver contrast after the application of gadolinium polymer was the basis for a better and prolonged visibility of the abscesses, as compared with images acquired after injection of gadopentetate dimeglumine.     

Conservative management of chronic renal failure

Failing kidneys can play havoc with other parts of the body. Specific treatment of these associated problems may help ward off uremia and preserve whatever renal function remains. Sodium levels may drop if too much water is mistakenly given to counteract kidney failure. Hyperkalemia can lead to cardiac arrest if potassium levels aren't reduced without delay. Acidosis also may reach life-threatening proportions, especially if diarrhea occurs. Almost all patients with chronic renal failure have a bleeding tendency and anemia, with the hematocrit dipping as low as 20 percent. Over half have decreased tolerance to carbohydrares, although severe hyperglycemia is rare. Disorders of calcium metabolism also are common, ranging from asymptomatic hypocalcemia to osteomalacia. The kidneys' impaired filtration ability should be kept in mind when drugs are prescribed. Dosages may need to be cut to avoid an adverse reaction.     

A comparison of the effect of two regimens of infestation on the development of resistance by cattle to the cattle tick, Boophilus microplus (Can.)

The development of resistance to Boophilus microplus by cattle was studied using sets of cattle twins, in stalls. One twin from each set received 3 infestations of 40,000 larvae and the other a continuous infestation of 1,000 larvae a day over the same period. Sets of twins were then challenged with 1,000 larvae a day for 40 days and 2 field infestations of 20,000 larvae. Correlations of ranking for resistance made at 40-day periods during daily infestations of 1,000 larval ticks or for corresponding intermittent infestations of 40,000 larvae were low until animals had received 120,000 larvae. Thereafter irrespective of method of infestation correlations of ranking were relatively high (r = 0.61-0.96) between periods of infestations or method of infestation including 2 field infestations. Fewer adult female ticks matured on the daily infested animals than on the intermittently infested animals during the treatment period, but animals developed a similar resistance level whether infested with either technique.     

Pyloric stenosis: a 13-year experience in operative management

Infantile hypertrophic pyloric stenosis is best treated surgically, after an appropriate period of rehydration and resuscitation. Our experience with this entity has resulted in the performance of fewer contrast studies to establish the diagnosis as well as the use of an operative technique which can be safely applied to the teaching environment.     

Demonstration of neuraminidase activity in human blood serum and human milk using a modified, radioactively labelled alpha1-glycoprotein as substrate

N-Acetylneuramini acid of alpha1-glycoprotein was oxidized with a small molar excess of periodate and reduced with tritium-labelled borohydride. By this method about 50% of the N-acetylneuraminic acid was converted to its radioactively labelled C8-analog and 25% to its C7-analog. Using this modified alpha1-glycoprotein as substrate, minimum neuraminidase concentrations of 10(-18) units/ml, related to the activity of neuraminidase from Vibrio cholerae, could be determined. Neuraminidase activity was demonstrated in 95% of the sera or blood plasma samples from a series of 417 healthy or ill human individuals and in milk samples from 5 different donors. The neuraminidase in both serum and milk had optimal activity at pH 5.5. On an average, 10(-10) neuraminidase units were found in 1 ml serum and 10(-8) units in 1 ml milk. Although the neuraminidase activities in the sera varied, a correlation with definite pathological states is not yet possible. N-Acetylneuraminate pyruvate-lyase activity could not be detected in human serum.     

Gated blood pool imaging following 99mTc stannous pyrophosphate imaging

Cardiac patients who have undergone 99mTc-stannous pyrophosphate (99mTc-PYP) myocardial imaging can be injected 24 hours later with 99mTc-pertechnetate (99mTc04) to assess left ventricular function. Reduction of 99mTc04 by tin remaining in the blood following the stannous pyrophosphate injection causes labeling of the red cells by 99mTc04 and the creation of a vascular tracer suitable for electrocardiographically gated imaging.