Ultrasonic detection of nonopaque renal calculi

Four patients with 5 nonopaque renal calculi composed of uric acid were examined by ultrasound. The calculi varied in size from a 1.5 X 1.5-cm intrapelvic stone to a staghorn calculus measuring 4 cm. All stones were satisfactorily imaged by ultrasound, allowing a diagnosis of nephrolithiasis to be made with confidence in each case. In 2 patients with poor excretion on urography, the diagnosis was not suspected prior to the ultrasound examination. The authors feel that ultrasound has great potential value in the investigation of nonopaque filling defects of the renal pelvis and in patients with urographic nonvisualization who have a high risk of uric acid lithiasis.     

Intrahepatic amebic abscesses: indications for and results of percutaneous catheter drainage

Medical therapy is standard for intrahepatic amebic abscess and generally is effective. However, we have encountered a group of patients in whom percutaneous aspiration and drainage was indicated due to uncertainty of diagnosis or clinical deterioration of the patient. Twenty such patients underwent percutaneous drainage with ultrasound or CT guidance, and each patient was cured (appropriate antibiotics were administered concomitantly). The specific indications for intervention were to differentiate pyogenic from amebic abscess, pain and imminent rupture, poor response to medical therapy, false-negative results of serologic tests, noncompliance with medical treatment, left lobe abscess, and pregnancy. Diagnosis of amebiasis from examination of the fluid was seldom possible, while findings from core biopsy of the wall of the abscess led to diagnosis in three cases. Recurrence necessitating redrainage occurred in three patients; in each, catheters were removed the same day drainage was performed. There were three minor complications. Differences from percutaneous management of pyogenic abscesses included more rapid removal of catheters (four days), more frequent use of US guidance, and more common use of the prone angled approach to avoid pleural contamination. Catheter drainage may be curative and may expedite care for problematic amebic liver abscesses in selected cases.     

Event-related potentials and neuropsychological tests in obsessive-compulsive disorder

OBJECTIVE: Previous studies have provided evidence from event-related potentials (ERPs) and neuropsychological testing of abnormal cognitive processing in obsessive-compulsive disorder (OCD). The aim of this study was to further characterize the cognitive functions of the patients with OCD by utilizing ERPs and neuropsychological tests. METHODS: ERPs were recorded in a group of 31 drug-free OCD patients without depression and 30 normal controls following verbal auditory stimuli using an oddball paradigm. The specific neuropsychological tests administered to assess cognitive functions in all participants were the Stroop Test, Trail Making Test, Design Fluency Test, Controlled Word Association Test (Verbal Fluency test). RESULTS: The patient group showed shorter P300 duration compared to normal controls. In neuropsychological tests, no significant differences were found between the two groups. Negative correlations between Stroop duration and P300 amplitudes in occipital, parietal, and temporal anterior regions were observed. CONCLUSION: Shorter P300 duration may indicate an acceleration in the P300 process, and speeding of cognitive processing, dysfunction of cortico-subcortical circuits, or some combination of all of the above.     

N'-(3'-monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine formation by peroxidative metabolism

N'-(3'-Monophospho-deoxyguanosin-8-yl)-N-acetylbenzidine (dGp-ABZ) is thought to play an important role in initiation of benzidine-induced bladder cancer in humans. This report assesses the possible formation of this adduct by peroxidatic activation of N-acetylbenzidine (ABZ). Adduct formation was measured by 32P-post-labeling. Ram seminal vesicle microsomes were used as a source of prostaglandin H synthase (PHS). The peroxidatic activity of PHS was compared with that for horseradish peroxidase. Both peroxidases converted ABZ to dGp-ABZ whether DNA or 2'- deoxyguanosine 3'-monophosphate (dGp) was present. Following 32P-post- labeling, the enzymatic and synthetic adduct were extracted from PEI- cellulose plates and were shown to have the same HPLC elution profiles for the bisphosphate adduct (32P-dpGp-ABZ). Treatment of the enzymatic and synthetic bisphosphate adduct with nuclease P1 yielded a product that eluted at the same time from the HPLC (32P-dpG-ABZ). Additional experiments demonstrated that the PHS-derived 5'-monophosphate (dpG- ABZ) and 3'-monophosphate (dGp-ABZ) adducts were also identical to their corresponding synthetic standard. With comparable amounts of total ABZ metabolism, PHS produced approximately 40-fold more dGp-ABZ than horseradish peroxidase (1943 +/- 339 versus 49 +/- 7.8 fmol/mg dGp). Adduct formation was dependent upon the presence of peroxidase and the specific substrate, i.e. arachidonic acid or H2O2. Adduct formation by PHS was inhibited by indomethacin (0.1 mM), ascorbic acid (1 mM) and glutathione (10 mM), but not by 5,5-dimethyl-1-pyrroline N- oxide (DMPO) (100 mM), a radical scavenger. Horseradish peroxidase adduct formation was also inhibited by ascorbic acid and glutathione. In addition, DMPO elicited greater than a 96% inhibition. Results demonstrate peroxidatic metabolism of ABZ to form dGp-ABZ. The mechanism of dGp-ABZ formation by PHS and horseradish peroxidase may be different.