The child as logician or methodologist? A critique of formal operations.
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Biomedical subjects
Publications and source records attributed to S Strauss.
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The motor activity of rats following medication with monoamine-oxidase inhibitors was registered continuously over a period of nine days. At the same time the enzyme activity of monoamineoxidase (MAO) form A and B and the concentration of serotonin, tryptophan, 5-hydroxyindolacetic acid and norepinephrine were measured in brain stem and hippocampi. We draw the following conclusions: 1. The rhythmic changes in the levels of serotonin and norepinephrine play a minor role in the circadian rhythm. 2. MAO-inhibitors influence the timing mechanism. A relationship between this finding and the therapeutic effect on depressed patients is discussed. 3 Dopaminergic neurons antagonize the activation by adrenergic neurons during the dark-period.
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BACKGROUND: Perforation of the gallbladder with cholecystohepatic communication is a rare cause of liver abscess. We report four cases of this condition and describe the imaging procedures related to its diagnosis and treatment. METHODS: The medical and x-ray files of 39 patients with percutaneous drainage of liver abscesses were retrospectively reviewed. Four patients with hepatic abscess due to gallbladder perforation were identified. The patients presented with clinical features suggestive of cholecystitis. RESULTS: Sonography in four patients showed a hypoechoic lesion in the liver adjacent to the gallbladder. CT in three patients showed a hypodense area in the liver, corresponding to the sonographic findings. Percutaneous abscess drainage, followed by an abscessogram, was performed in all patients. Contrast material injected through the drainage catheter filled the gallbladder directly from the abscess cavity. Two patients subsequently underwent cholecystectomy, confirming perforation of the gallbladder fundus. In both cases the gallbladder was noted to be embedded in the liver and covered by adhesions. CONCLUSION: Perforation of the gallbladder is a rare cause of pyogenic liver abscess. We suggest, however, based on our two patients who underwent surgery, and several cases reported in the literature, that this condition may be more common when the gallbladder is partially or totally intrahepatic.
Four patients with postappendectomy abscesses complicated by enteric fistulae were treated by percutaneous drainage. Sinograms, obtained at the time of the initial drainage, demonstrated communication to the cecum in 3 patients and to the small bowel in 1 patient. Complete cure was attained in 3 patients by percutaneous drainage. In the fourth patient, surgery was performed after 7 days of catheter drainage. Percutaneous drainage of abscesses with enteric communication requires a modified technique, which includes longer-term drainage than for simple noncommunicating abscesses.
BACKGROUND: We report the occurrence of congenital anomalies of the inferior vena cava (IVC) and right renal aplasia in three patients as detected on computed tomography (CT). METHODS: The medical records and imaging studies of three patients with congenital anomalies of the IVC and right renal aplasia were studied. We also reviewed eight reported cases with such an association. RESULTS: Eleven patients, nine adults and two girls, were included in the series. Indications for imaging included deep vein thrombosis (n = 5), hypertension (n = 2), failure to advance a femoral vein catheter cranially (n = 1), dilated veins along the abdominal wall (n = 1), endstage renal failure (n = 1), and jaundice (n = 1). CT was performed in seven patients, and venography, aortography, and other imaging modalities were performed in four. IVC anomalies included partial or complete absence of the IVC in nine patients and a double vena cava in two. The azygos vein was very prominent in all patients in whom the IVC was absent. The right kidney was absent or very small in all patients. CONCLUSION: The association between IVC anomalies and absence of the right kidney as detected on CT probably was not incidental. Although most patients had symptoms deriving from the anomalies, these might have been clinically silent. The radiologist should be aware of the possible association between these anomalies, which can be detected on CT.
Normal lung development is dependent on epithelial-mesenchymal interactions. This study was undertaken to examine the structure of the interstitium of the developing human fetal lung, concentrating particularly on the first and second trimesters. Lung tissue was obtained at autopsy from nonmalformed, nonmacerated cases of spontaneous abortion (n = 15), stillbirth (n = 9), and very early neonatal death (n = 5) (range of gestations, 10-42 weeks). Paraffin-embedded tissue sections were examined using immunohistochemical methods to determine expression of collagens I, III, IV, V, and VI; the glycoproteins fibronectin and laminin; and the intermediate filaments vimentin, alpha-smooth muscle actin (alphaSMA), and desmin. Collagens III and VI and cells expressing alphaSMA were present consistently at points of airway branching and secondary crest formation, indicating a role for these components in the initiation and stabilization of airway branches in the developing lung. Desmin expression by stromal cells succeeded alphaSMA temporally, and may represent a marker of terminal smooth muscle differentiation within the airway; it was not detected in the vascular tree. Other components were widely expressed throughout the extracellular matrix, including basement membranes, at all gestations. The spatial and temporal patterns of expression of components of the lung interstitium provide clues to the mechanisms underlying normal human lung development and possible insights into the pathogenesis of fetal and neonatal lung disease.
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The cytokine interleukin-6 is consistently detected in the brains of Alzheimer's disease patients but not in the brains of nondemented elderly persons. Until recently it was unclear whether an interleukin-6-associated inflammatory mechanism is an early or late event in the pathological cascade of Alzheimer's disease. We investigated whether interleukin-6 could be detected in plaques of Alzheimer's disease patients prior to the onset of neuritic degeneration. We found interleukin-6 mostly in plaques where neuritic pathology has not yet developed. This indicates that the appearance of interleukin-6 may precede neuritic changes and is not just a consequence of neuritic degeneration. Therefore, one may hypothesize that activation of inflammatory mechanisms may cause neuritic degeneration in plaques. A suppression of interleukin-6 synthesis could, therefore, be of therapeutic value. Upon screening a number of substances, we found that a small number of nonsteroidal antiinflammatory drugs, including tenidap, were able to inhibit interleukin-6 synthesis in cultured human astrocytoma cells. These substances may be therapeutically useful in Alzheimer's disease and should be evaluated in clinical studies.
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OBJECTIVE: The aim of our study was to evaluate whether intracardiac echogenic foci (ICEFs) may be associated with increased risk for structural cardiac anomalies in the low-risk population. METHODS: During a 24-month period, 3,744 low-risk patients were prospectively screened for ICEFs by prenatal sonography. The study group was composed of 138 fetuses (3.7%) with ICEF. The control group was composed of 167 fetuses without ICEF. In all fetuses a complete echocardiographic evaluation was performed. RESULTS: Among the 138 fetuses in the study group, 108 (78%) ICEFs were found in the left ventricle, 25 (18%) were found in the right ventricle, and 5 (4%) were found to be bilateral. No statistically significant difference was found between the study and the control group regarding the presence of cardiac anomalies. Only 1 case (0.7%) of pulmonic stenosis was found in the study group, compared to 1 case (0.6%) of bicuspid aortic valve in the control group. CONCLUSIONS: We conclude that ICEFs found in low-risk patients are not associated with a significant increase in the risk of cardiac anomalies.
Long-term follow-up of a tenotomized Achilles tendon reveals healing with formation of a tendonlike structure between the cut tendon ends. A prospective study to show sonographic healing stages was designed. Twelve patients (21 Achilles tendons) with the diagnosis of cerebral palsy, spastic diplegia, and shortening of their Achilles tendons underwent a tenomuscular release. The healing process was documented by monthly ultrasound studies. Overall, 102 examinations were done, with a mean follow-up of 5.3 months. The authors found six distinct healing stages, with no significant change occurring in the length of the primary gap at the tenotomy site throughout healing. Based on these results, the authors conclude that sonographic healing stages of the cut Achilles tendon can be defined and staged. They also suggest that transverse tenotomy at the tenomuscular junction is a safe method, with no risk of overlengthening.