高分辨率CT对颞部疾病的检查价值

目的：探讨高分辨率CT（HRCT）对颞部疾病的检查价值。方法：对43例颞部疾病患者行常规CT和高分辨率CT（HRCT）检查所获图像对比分析，并讨论HRCT的检查技术和图像后处理。结果：HRCT对病变的显示率及病变引起骨质破坏的程度，病变边缘，轮廓的显示均明显优于常规CT，尤其能清楚显示常规CT难以显示的中耳及内耳的细微结构，结论：高分辨率CT是颞部疾病的首选检查方法，使用高分辨率CT对颞部疾病的检查给临床提供更多，更准确的诊断信息。     

Intratemporal vascular tumors: detection with CT and MR imaging

The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion.     

Incorporating abbreviated EEGs in the initial workup of patients who present to the emergency room with mental status changes of unknown etiology.

Patients frequently present to the emergency room (ER) with mental status changes without obvious cause. The EEG is underused in this population. The authors investigated whether an abbreviated EEG (AbEEG) can be incorporated in the early evaluation of these patients to provide useful information. A 5-minute AbEEG was performed using a preformed electrode placement system on 25 patients who presented to the ER with mental status changes of unknown cause. AbEEG findings were categorized as normal, showing diffuse abnormalities, focal abnormalities, electrographic seizures, or uninterpretable. Using retrospective chart review, the authors determined if the cause of mental status change was a diffuse encephalopathy or a nonneurologic event (DENNE), a focal brain abnormality, nonconvulsive status epilepticus (NCSE), psychogenic, or unknown, and if particular AbEEG findings were associated with specific causes of altered sensorium. The AbEEG identified NCSE in two patients who presented with new-onset seizures. The presence of diffuse slowing on the AbEEG was highly suggestive of mental status changes due to DENNE. AbEEGs can be successfully incorporated in the early evaluation of patients who present to the ER with mental status changes of unknown cause and provide useful information in this setting.     

骨巨细胞瘤的MRI诊断价值

目的探讨骨巨细胞瘤的MRI表现特点及其病理基础。资料与方法搜集经手术病理证实的12例骨巨细胞瘤患者资料，分析其MRI征象并与病理结果对照。结果T1WI上肿瘤实体表现为低、等信号，T2WI上为不均匀高信号，Gd-DTPA增强扫描呈中度到明显强化。此外，MRI还可显示肿瘤内坏死、出血、含铁血黄素沉着等。结论MRI能够提供比较全面的影像学信息，可提高对骨巨细胞瘤诊断的准确性。     

Metabolic response of isolated liver cells to in vivo phagocytic challenge

This study elucidates the in vivo metabolic response of different liver cells after a single phagocytic challenge. In vivo glucose uptake of different tissues and isolated liver cells was determined by a sequential double labeling version of the 2-deoxyglucose technique. After latex administration, glucose uptake more than doubled in the liver, increased by about 50% in the spleen and lung and was not changed in muscle and testis. Within 10 min after intravenous injection of latex beads, neutropenia developed, with no change in the number of lymphocytes. This was accompanied by a marked influx of polymorphonuclear leukocytes into the liver. Latex was found in 52%, 35%, and 14% of the isolated Kupffer cells, polymorphonuclear leukocytes and endothelial cells, respectively. In vivo glucose uptake increased by 111%, 142%, and 43% in these cells. Glucose uptake by the latex-free hepatocytes was also elevated, presumably by way of intercellular signals between parenchymal and non-parenchymal liver cells. Indomethacin pretreatment resulted in the delay of neutrophil immigration into tissues without any change in the glucose response of different liver cells. Thus phagocytic stimulation in vivo results in marked neutropenia, migration of neutrophils into the liver, increased glucose uptake by phagocytic cells of the liver and enhanced glucose metabolism by the non-phagocytic parenchymal cells.     

Novel proteins with binding specificity for DNA CTG repeats and RNA CUG repeats: implications for myotonic dystrophy

While an unstable CTG triplet repeat expansion is responsible for myotonic dystrophy, the mechanism whereby this genetic defect induces the disease remains unknown. To detect proteins binding to CTG triplet repeats, we performed bandshift analysis using as probes double- stranded DNA fragments having CTG repeats [ds(CTG)6-10] and single- stranded oligonucleotides having CTG repeats ss(CTG)8 or RNA CUG triplet repeats (CUG)8. The source of protein was nuclear and cytoplasmic extracts of HeLa cells, fibroblasts and myotubes. Proteins binding to the double-stranded DNA repeat [ds(CTG)6-10], were inhibited by nonlabeled ds(CTG)6-10, but not by a non-specific DNA fragment (USF/AD-ML). Another protein binding to ssCTG probe and RNA CUG probe was inhibited by nonlabeled (CTG)8 and (CUG)8. Nonlabeled oligos with different triplet repeat sequences, ss(CAG)8 or ss(CGG)8, did not inhibit binding to the ss(CTG)8 probe. However, when labeled as probes, the (CAG)8 and (CGG)8 bound to proteins distinct from the CTG proteins and binding was inhibited by nonlabeled (CAG)8 or (CGG)8 respectively. The protein binding only to the RNA repeat (CUG)8 was inhibited by nonlabeled (CUG)8 but not by nonlabeled single- or double-stranded CTG repeats. Furthermore, the CUG-BP exhibited no binding to an RNA oligonucleotide of triplet repeats of the same length but having a different sequence, CGG. The CUG binding protein was localized to the cytoplasm, whereas dsDNA binding proteins were localized to the nuclear extract. Thus, several trinucleotide binding proteins exist and their specificity is determined by the triplet sequence. The novel protein, CUG-BP, is particularly interesting since it binds to triplet repeats known to be present in myotonin protein kinase mRNA which is responsible for myotonic dystrophy.      

Differences in glycinergic mIPSCs in the auditory brain stem of normal and congenitally deaf neonatal mice

We have investigated the fundamental properties of central auditory glycinergic synapses in early postnatal development in normal and congenitally deaf (dn/dn) mice. Glycinergic miniature inhibitory postsynaptic currents (mIPSCs) were recorded using patch-clamp methods in neurons from a brain slice preparation of the medial nucleus of the trapezoid body (MNTB), at 12-14 days postnatal age. Our results show a number of significant differences between normal and deaf mice. The frequency of mIPSCs is greater (50%) in deaf versus normal mice. Mean mIPSC amplitude is smaller in deaf mice than in normal mice (mean mIPSC amplitude: deaf, 64 pA; normal, 106 pA). Peak-scaled fluctuation analysis of mIPSCs showed that mean single channel conductance is greater in the deaf mice (deaf, 64 pS; normal, 45 pS). The mean decay time course of mIPSCs is slower in MNTB neurons from deaf mice (mean half-width: deaf, 2.9 ms; normal, 2.3 ms). Light- and electron-microscopic immunolabeling results showed that MNTB neurons from deaf mice have more (30%) inhibitory synaptic sites (postsynaptic gephyrin clusters) than MNTB neurons in normal mice. Our results demonstrate substantial differences in glycinergic transmission in normal and congenitally deaf mice, supporting a role for activity during development in regulating both synaptic structure (connectivity) and the fundamental (quantal) properties of mIPSCs at central glycinergic synapses.     

Prevalences, genotypes, and risk factors for HIV transmission in South America

HIV cross-sectional studies were conducted among high-risk populations in 9 countries of South America. Enzyme-linked immunosorbent assay screening and Western blot confirmatory testing were performed, and env heteroduplex mobility assay genotyping and DNA sequencing were performed on a subset of HIV-positive subjects. HIV prevalences were highest among men who have sex with men (MSM; 2.0%-27.8%) and were found to be associated with multiple partners, noninjection drug use (non-IDU), and sexually transmitted infections (STIs). By comparison, much lower prevalences were noted among female commercial sex workers (FCSWs; 0%-6.3%) and were associated mainly with a prior IDU and STI history. Env subtype B predominated among MSM throughout the region (more than 90% of strains), whereas env subtype F predominated among FCSWs in Argentina and male commercial sex workers in Uruguay (more than 50% of strains). A renewed effort in controlling STIs, especially among MSM groups, could significantly lessen the impact of the HIV epidemic in South America.