C60的化学反应性和高分子化

综述了C_(60)化学研究的进展。C_(60)的化学反应性的研究展现了一个广阔的新领域,并使C_(60)作为一种新型的功能基团引入高分子成为现实。这些进展为进一步深入研究C_(60)尤其是C_(60)的材料化提供了前提。     

Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child

Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs.     

Age-related Changes in Bovine α-crystallin and High-molecular-weight Protein

The high-molecular-weight (HMW) protein from the lens is composed mostly of α-crystallin in a highly aggregated state. Bovine HMW protein was carefully separated from α-crystallin by size-exclusion chromatography. α-Crystallin has chaperone-like ability whereby it stabilizes other proteins under conditions of stress (e.g. heat). Comparison of bovine HMW protein and α-crystallin shows that the HMW protein has a markedly reduced chaperone ability compared to α-crystallin. However, in contrast to the results of other workers, we observe no alteration with age in the ability of α-crystallin to act as a chaperone. Using electrospray ionisation mass spectrometry, changes in the phosphorylation of the α-crystallin subunits with age have been quantified. Phosphorylation of α-crystallin occurs early in life but does not alter in proportion after about three years of age. In addition, phosphorylation of the A subunit of α-crystallin has little effect on its chaperone ability. As is found in the artificially prepared HMW complex of α- and γ-crystallin, NMR spectroscopy shows that in the naturally occurring HMW protein, the short C-terminal extension of the α_Bsubunit has lost its flexibility whereas the α_Asubunit extension is still flexible. Post-translational modifications therefore seem to have little effect on the chaperone action of α-crystallin, but alterations in the quaternary structure of α-crystallin via incorporation into the HMW aggregate, lead to major changes in the chaperone ability of the protein. The results are consistent with the notion that one of the contributing factors to cataract formation in the lens is the depletion of α-crystallin with age as it is converted into the HMW protein.     

Clinical Studies on Functional Dyspepsia Treated with Different Dosage-Form of Zhishi Xiaopi Pill Recipe (枳实消痞丸方)

Ｄｙｓｐｅｐｓｉａｒｅｆｅｒｓｔｏｐａｉｎｏｒｄｉｓｃｏｍｆｏｒｔｆｏ ｃｕｓｅｄｉｎｔｈｅｅｐｉｇａｓｔｒｉｕｍ，ｗｈｉｃｈｗａｓｒｅｐｏｒｔｅｄｔｏｏｃｃｕｒｉｎｍｏｒｅｔｈａｎ 1 0 %ｏｆｏｕｔｐａｔｉｅｎｔｓｉｎｉｎｔｅｒｎａｌｍｅｄｉｃｉｎｅ，ａｎｄｎｅａｒｌｙｈａｌｆｔｈｅｐａｔｉｅｎｔｓｉｎｔｈｅｇａｓ ｔｒｏｉｎｔｅｓｔｉｎａｌ（ＧＩ）ｄｅｐａｒｔｍｅｎｔ（1）．Ａｌｍｏｓｔｈａｌｆｏｆｔｈｅｓｅｐａｔｉｅｎｔｓｗｉｔｈｄｙｓｐｅｐｓｉａｗｈｏｈａｖｅｎｏｄｅｆｉ ｎｉｔｅｏｒｇａｎｉ…     

功能性消化不良的药物治疗

功能性消化不良是一种高发性疾病,常影响着人们的生活质量,被视为重要的消化道疾病.虽然已有达成共识的罗马标准,功能性消化不良呈现出多种多样的症状.本文尝试为临床提供治疗的选择,包括幽门螺杆菌的清除、抑酸治疗、促胃肠动力药、抗抑郁药等.总的来说,根据主要症状来选择治疗方法是可行和有效的.     

Nonlinear sensory cortex response to simultaneous tactile stimuli in writer's cramp.

Writer's cramp is a task-specific dystonia that leads to involuntary hand postures during writing. Abnormalities of sensory processing may play a pathophysiological role in this disorder. Electrophysiology studies in a monkey model of focal dystonia have revealed de-differentiation of sensory maps and the existence of single cells in hand regions of area 3b with enlarged receptive fields that extend to the surfaces of more than one digit. These changes may lead to abnormal processing of simultaneous sensory inputs. To study abnormal processing of simultaneous sensory information in adult humans with writer's cramp, we used functional magnetic resonance imaging to compare the response in primary sensory cortex with simultaneous tactile stimulation of the index and middle finger, with the response to stimulation of each finger alone. We tested five patients with writer's cramp and seven unaffected (normal) subjects. In the normal subjects, a linear combination of the activation patterns for individual finger stimulation predicts the pattern of activity for combined stimulation with 12% error. In writer's cramp patients, the linear combination predicted the combined stimulation pattern with 30% error. Results indicate a nonlinear interaction between the sensory cortical response to individual finger stimulation in writer's cramp. This altered interaction may contribute to the motor abnormalities.     

New insights on COPD imaging via CT and MRI

Multidetector-row computed tomography (MDCT) can be used to quantify morphological features and investigate structure/function relationship in COPD. This approach allows a phenotypical definition of COPD patients, and might improve our understanding of disease pathogenesis and suggest new therapeutical options. In recent years, magnetic resonance imaging (MRI) has also become potentially suitable for the assessment of ventilation, perfusion and respiratory mechanics. This review focuses on the established clinical applications of CT, and novel CT and MRI techniques, which may prove valuable in evaluating the structural and functional damage in COPD.     

头颈部良性神经源性肿瘤1H MRS的表现特点

目的：探讨头颈部良性神经源性肿瘤在单体素^1H MRS上的表现特点。材料和方法：共收集经单体素。HMRS检查，并经手术病理证实的头颈部神经源性肿瘤14例（神经鞘瘤11例，神经纤维瘤2例，颈动脉体瘤1例）。采用点分析波谱法（PRESS：TE=144ms，14例）和激励回波法（STEAM：TE=30ms，11例）进行。HMRS空间定位，以胆碱和脂质代谢物为标准评价所有肿瘤。波谱图上，胆碱和脂质分别在3．2ppm和0．9—1．4ppm区域识别。结果：采用PRESS后，14例神经源性肿瘤中检测出胆碱代谢物者11例，检出脂质代谢物者6例。胆碱和脂质代谢物同时检出者5例，仅检出胆碱者6例，仅检出脂质者1例，胆碱和脂质均未检出者2例。采用STEAM后，11例肿瘤中检出胆碱代谢物和脂质者分别为3例和8例。结论：头颈部良性神经源性肿瘤的单体素。HMRS表现具有多样性，多数肿瘤以长TEPRESS上胆碱峰的显示为特点，长TEPRESS能较STEAM更好地检出良性神经源性肿瘤内的胆碱代谢物。     

Proton magnetic resonance spectroscopy in childhood brainstem lesions

Background Diagnosis of brainstem lesions in children based on magnetic resonance imaging alone is a challenging problem. Magnetic resonance spectroscopy (MRS) is a noninvasive technique for spatial characterization of biochemical markers in tissues and gives information regarding cell membrane proliferation, neuronal damage, and energy metabolism. Methods We measured the concentrations of biochemical markers in five children with brainstem lesions and evaluated their potential diagnostic significance. Images and spectra were acquired on a 1.5-T imager. The concentrations of N-acetylaspartate, tetramethylamines (e.g., choline), creatine, phosphocreatine, lactate, and lipids were measured within lesions located at the brainstem using Point-resolved spectroscopy sequences. Results Diagnosis based on localized proton spectroscopy included brainstem glioma, brainstem encephalitis, demyelination, dysmyelination secondary to neurofibromatosis type 1 (NF 1), and possible infection or radiation necrosis. In all but one patient, diagnosis was confirmed by biopsy or by clinical follow-up. Conclusions This small sample of patients suggests that MRS is important in the differential diagnosis between proliferative and nonproliferative lesions in patients without neurofibromatosis. Unfortunately, in cases of NF 1, MRS can have a rather misdiagnosis role.     

Dysaccommodation of the stomach: therapeutic nirvana?

Functional dyspepsia (FD) is a highly prevalent gastrointestinal disorder and has a complex pathophysiology. Impaired fundic relaxation in response to a meal is present in 40% of patients with FD. This review focuses on impaired gastric accommodation of the stomach as a pathophysiological mechanism and the possible therapeutic targets that can be derived from the current knowledge of the neuroregulation of the accommodation reflex. First the different means of gastric accommodation assessment are described and the relationship between symptoms and impaired gastric accommodation. The different therapeutic options are subsequently discussed in view of their molecular target, based on the different receptor subtypes involved in the accommodation reflex. Although impaired gastric accommodation is highly prevalent in dyspeptic patients and basic knowledge about the accommodation reflex enables to develop pathophysiologically targeted therapies, it is unlikely that therapies aimed at dysaccommodation of the stomach will lead to symptom relief in all dyspeptic patients. A major challenge is the development of methods that readily identify impaired accommodation in clinical practice.