The junctional parenchymal defect: a sonographic variant of renal anatomy

A triangular echogenic area in the upper pole renal parenchyma can be identified at times during routine sonography of the right kidney. Thirty such cases are presented. Occasionally similar echogenic defects in the parenchyma can be seen posteriorly in the lower pole and in the left kidney. These defects in the parenchyma result from normal extensions of the renal sinus of kidneys that have a distinct division of their upper and lower poles. This is due to partial fusion of two embryonic parenchymatous masses called renunculi. The defects in the parenchyma occur at the junction of the renunculi; hence we have termed them junctional parenchymal defects. In order to differentiate them from pathologic conditions, one must identify their characteristic location and demonstrate continuity with the renal sinus.     

Classic migraine: Effective prophylaxis with metoprolol

Metoprolol slow-release tablets (Durules®), 200 mg, given once daily in the morning were compared with placebo in the prophylaxis of classic migraine. The trial comprised eight Scandinavian neurologic centres and was designed as a double-blind cross-over study with 4 weeks' run-in, four weeks washout, and 8 weeks of either treatment. Seventy-seven patients with two to eight migraine attacks per month were entered in the trial, and 73 completed it. A total of 1119 attacks with aura symptoms and 374 without were recorded. Metoprolol was significantly better than placebo with regard to the total frequency of attacks (1.8 versus 2.5 attacks/4 weeks), mean duration of attacks (6.0 versus 8.0 h/attack), mean global rating, and consumption of analgesics per attack: Similar differences could be shown for attacks with aura symptoms alone, except for the duration of attacks. Metoprolol is the first drug for which a prophylactic effect in classic migraine has been convincingly demonstrated.     

Functional interactions between the medial temporal lobes and posterior neocortex related to episodic memory retrieval

We applied structural equation modeling to positron emission tomography data in humans to examine functional interactions between the right medial temporal lobe (MTL) and selected right neocortical regions in relation to visual recognition memory. Using a priori knowledge about anatomical connections between these regions as a guiding constraint, we modeled the pattern of interactions [i.e. covariances in regional cerebral blood flow (rCBF)] associated with episodic memory retrieval of spatial location and compared it with the pattern for retrieval of object identity. We also compared these patterns with those associated with perceptual matching of spatial location and object identity. Although displaying no difference in average rCBF across tasks, the right MTL showed domain-specific qualitative differences in interactions with posterior dorsal (parieto-occipital sulcus, supramarginal gyrus) and ventral regions (fusiform gyrus, superior temporal sulcus) but not with a prefrontal region. MTL interactions involving dorsal regions were positive in the spatial retrieval task but negative for object retrieval. Interactions involving ventral regions showed the reverse pattern. No comparable changes were observed during perceptual matching. Using control models, we demonstrated the neuroanatomical specificity of these results. Our results provide support for the notion that the nature of interactions between the MTL and posterior neocortex depends on the domain of information to-be- recovered.      

Exudative lung injury is associated with decreased levels of surfactant proteins in a rat model of meconium aspiration

OBJECTIVE: Meconium aspiration syndrome remains a common cause of respiratory failure in neonates. The acute effects of meconium aspiration are inactivation of lung surfactant in vivo and in vitro. This study investigated the delayed effects of meconium on alveolar surfactant phospholipids and protein levels in spontaneously breathing animals. METHODS: Twenty-two adult rats were given 4.3 mg of dry weight human meconium after endotracheal intubation. Rats were briefly mechanically ventilated in room air, extubated, then killed after 16 (n = 6), 24 (n = 6), 48 (n = 6), and 72 hours (n = 4). Control animals received the same volume of normal saline (n = 7) or no meconium (n = 7). Bronchoalveolar lavage and tissue specimens were evaluated for inflammatory cells, total proteins, surfactant phospholipids, and surfactant proteins. RESULTS: Meconium caused exudative lung injury that was reflected in increased cell counts and proteins in alveolar lavage fluid. The peak injury occurred at 16 hours after instillation, whereas recovery occurred by 72 hours. Although total lavage fluid phospholipids did not change over time, phospholipid and dipalmitoyl phosphatidylcholine in large aggregates tended to decrease at 24 hours. Western blot analysis demonstrated time-dependent qualitative decreases in surfactant proteins A and B (SP-A, SP-B) in meconium-instilled animals compared with the controls. ELISA for SP-B confirmed the Western blot findings with total SP-B in large aggregate decreasing from 25 +/- 4 microg in controls to 6.6 +/- 0.8 microg at 24 hours of injury. CONCLUSIONS: Our study suggests that the exudative lung injury with meconium instillation is associated with decreased levels of SP-A and SP-B in the large aggregate fraction of lung surfactant. We speculate that decreased secretion and/or increased degradation accounts for lower levels of SP-B in bronchoalveolar lavage fluid.     

Perforated diverticulum of the ascending colon: Pre-operative diagnosis by ultrasound

A case of acute perforation of a diverticulum of the ascending colon is presented. The ultrasound features that helped in making a pre-operative diagnosis are discussed. This rare surgical emergency and the similar clinical entities of perforated caecal or transverse colon diverticula are often clinically misdiagnosed as more common conditions such as acute appendicitis, acute cholecystitis or perforated ulcer. Awareness of this entity will help radiologists in making a correct pre-operative diagnosis.     

实体肿瘤血管任意方向生成的二维数值模拟

目的　二维数值生成实体肿瘤任意方向生长的血管网，为研究实体肿瘤内血液动力学、药物输运以及抗血管生成提供更趋真实的微血管网络结构。方法　将新生血管芽尖的内皮细胞迁移方向由先前模型的上、下、左、右四个方向扩展为任意方向，建立相应的二维离散模型，数值模拟实体肿瘤微脉管系统的生成过程，比较模拟结果与相关实验数据的符合程度。结果　对盲肠肿瘤微血管网进行数值模拟，与改进前的模型和其他模型比较，本模型生成的肿瘤微血管网结构特征，如血管的走向、扭曲、分叉与融合等，更接近生理实际，与实验观测图像的相似度更高。结论　该模型可模拟实体肿瘤的微血管网生成，为肿瘤内血液微循环、药物传递以及抗血管生成的理论研究提供较为接近实际的微血管网络结构。     

Pyruvate-dehydrogenase complex in ataxic patients: Enzyme deficiency in ataxic encephalopathy plus lactic acidosis and normal activity in Friedreich ataxia

Pyruvate dehydrogenase complex (PDHC) activity was measured in cultured fibroblasts from 12 patients with Friedreich's ataxia (FA), and in 1 patient with lactic acidosis and ataxia. The activities obtained after extraction of PDHC by different methods were compared. Triton-X-100 extraction yielded enzyme activities 5 to 10 times greater than those obtained with the older methods. With this sensitive technique, PDHC activity was markedly deficient in fibroblasts from the patient with lactic acidosis and ataxia but it was normal in the fibroblasts from FA patients. Mg ⁺⁺ activation of the PDHC in FA fibroblasts was normal.

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Sommario Il complesso enzimatico piruvico-deidrogenasi (PDHC) è stato misurato in fibroblasti coltivati da 12 pazienti con atassia di Friedreich ed 1 paziente con acidosi lattica e atassia. Le attività enzimatiche ottenute con diversi metodi di estrazione del PDHC sono stati confrontati. La estrazione con Triton-X-100 permetteva di ottenere attività enzimatiche da 5 a 10 volte più elevate di quelle ottenute con i metodi precedenti. Con questo sensibile metodo l'attività PDHC era molto ridotta nei fibroblasti del paziente con acidosi lattica e atassia: l'attività era invece normale nei fibroblasti dei pazienti con atassia di Friedreich. La attivazione del PDHC nei fibroblasti dei pazienti con Friedreich era normale.

     

Association between uncoupling protein polymorphisms (UCP2-UCP3) and energy metabolism/obesity in Pima indians

The UCP2-UCP3 gene cluster maps to chromosome 11q13 in humans, and polymorphisms in these genes may contribute to obesity through effects on energy metabolism. DNA sequencing of UCP2 and UCP3 revealed three polymorphisms informative for association studies: an Ala-->Val substitution in exon 4 of UCP2, a 45 bp insertion/deletion in the 3'- untranslated region of exon 8 of UCP2 and a C-->T silent polymorphism in exon 3 of UCP3. Initially, 82 young (mean age = 30 +/- 7 years), unrelated, full-blooded, non-diabetic Pima Indians were typed for these polymorphisms by direct sequencing. The three sites were in linkage disequilibrium ( P < 0.00001). The UCP2 variants were associated with metabolic rate during sleep (exon 4, P = 0.007; exon 8, P = 0.016) and over 24 h (exon 8, P = 0.038). Heterozygotes for UCP2 variants had higher metabolic rates than homozygotes. The UCP3 variant was not significantly associated with metabolic rate or obesity. In a further 790 full-blooded Pima Indians, there was no significant association between the insertion/deletion polymorphism and body mass index (BMI). However, when only individuals >45 years of age were considered, heterozygotes (subjects with the highest sleeping metabolic rate) had the lowest BMI (P = 0.04). The location of the insertion/deletion polymorphism suggested a role in mRNA stability; however, it appeared to have no effect on skeletal muscle UCP2 mRNA levels in a subset of 23 randomly chosen Pima Indians. In conclusion, these results suggest a contribution from UCP2 (or UCP3) to variation in metabolic rate in young Pima Indians which may contribute to overall body fat content later in life.