儿童腹腔脓肿的CT诊断

目的探讨ＣＴ对儿童腹腔脓肿的诊断价值。方法对２３例经手术和穿刺针吸证实的腹腔脓肿的ＣＴ表现进行分析，急性阑尾炎１３例，升结肠穿孔１例，美克尔憩室炎２例，感染源不明确７例。１９例行平扫与增强检查，４例仅平扫检查。结果脓液ＣＴ值与病程及致病菌种类无关，脓液量与病程呈正相关。５２％脓肿内见到气体影，２２％脓肿内见到小钙化斑。病程１周以上者全部见不均匀厚壁强化的脓肿壁。结论脓肿内见到小钙化斑和气体影像具有特征性，脓腔内较大气液平面提示肠瘘存在，脓肿内无气体影不能排除肠瘘。     

Enhanced regeneration in injured sciatic nerve by human amniotic mesenchymal stem cell.

OBJECTIVE: Amniotic fluid mesenchymal stem cells (MSCs) have the potential to differentiate into neuronal stem cells in vitro. We evaluated using amniotic fluid MSCs to support or enhance the ability of the injured sciatic nerve to cross a nerve gap. MATERIALS AND METHODS: We created a 5 mm nerve defect in Sprague Dawley rats. One group received therapy with MSCs embedded into woven oxidised regenerated cellulose gauze (Surgical; Ethicon, Somerville, NJ) and fibrin glue, while a control group received woven Surgicel and fibrin glue only. Evaluation methods included behavioural, electrophysiological and immunohistochemical studies. RESULTS: In gait analysis, the angle of the ankles in the treatment and control group were 46.4 degrees (standard deviation [SD]=15 degrees) and 36 degrees (SD=8.2 degrees), respectively, which was statistically significant (p=0.045). Five of 10 treated rats (50%) demonstrated partial foot movement, while none of the control group had any movement. The percentage amplitude of muscle compound action potential in the experimental group was 43% (SD=12.5%) compared to 29% (SD=8.8%) in the control group (p=0.038). The conduction latencies in the control and experimental groups was 2.5 ms (SD=0.45) and 1.7 ms (SD=0.47), respectively (p=0.005). Histological examination demonstrated that 70% of the treatment group achieved a maximum axon diameter percentage across the nerve gap of greater than 50%, compared with 0% in the control group. There were no differences in direction of fibre growth and fibrotic reaction between the two groups. CONCLUSION: Amniotic fluid MSC can augment growth of injured nerve across a nerve gap. This effect may be due to neurotrophic or induction effects of the MSC interacting with Schwann cells. Further study is required to determine the underlying mechanism of this effect.     

Rearrangement of immunoglobulin, T-cell receptor, and bcl-2 genes in malignant lymphomas in Hong Kong

The pattern of malignant lymphomas in the Hong Kong Chinese population is characterized by a low incidence of Hodgkin's disease and follicular lymphomas. The authors studied the immunoglobulin (Ig), T-cell receptor (TCR), and bcl-2 gene rearrangement in 62 cases of malignant lymphoma in this population by Southern blot hybridization. Two cases of Hodgkin's disease showed no rearrangement of the Ig and TCR genes. All 42 cases of B-cell lymphoma had Ig heavy chain (JH) rearrangement with or without additional rearrangement of the light chains (C kappa and C lambda). One case of diffuse B-cell lymphoma had additional T-cell receptor beta-chain (C beta) rearrangement. Sixteen of 18 cases of T-cell lymphoma had C beta rearrangement, and one case of T-lymphoblastic lymphoma had additional JH rearrangement. Two of eight (25%) cases of follicular lymphoma but only one of the 34 (2.9%) cases of diffuse B-cell lymphoma had bcl-2 rearrangement that was detected by pFL-1 probe. None of the 62 cases showed bcl-2 rearrangement using the pFL-2 probe. In conclusion, the Ig and TCR gene rearrangement pattern of the lymphomas found in Hong Kong correlates well with the T-cell and B-cell lineage, which is similar to reports in the white population. However, the incidence of bcl-2 gene rearrangement in follicular B-cell lymphoma is lower than that reported in the US but comparable with that in Japan.     

Relationship between magnesium levels in drinking water and sudden infant death syndrome.

The possible association between the risk of death from sudden infant death syndrome (SIDS) and the levels of magnesium in drinking water from municipal supplies was investigated in a matched case-control study in Taiwan. Characteristics for all SIDS deaths (501 cases) among Taiwan residents from 1988 through 1997 were compared with those of people who died from other causes (501 controls). The levels of magnesium in the drinking water of these residents were determined from data obtained from the Taiwan Water Supply Corporation (TWSC). The controls were pair-matched to the SIDS cases by sex, month and year of birth. The results of our study show that there is a significant trend towards a decreased risk of SIDS with increasing magnesium levels in drinking water.     

Differential effects of salen and manganese-salen complex (EUK-8) on the regulation of cellular cadmium uptake and toxicity.

Cadmium (Cd) stimulates the production of reactive oxygen species (ROS) and causes cell damage. We investigated here the feasibility of using a cell permeable superoxide dismutase/catalase mimetic, EUK-8, to reduce the Cd-induced ROS and cytotoxicity in Chinese hamster ovary cells. EUK-8 reduces the ROS level caused by Cd treatment. EUK-8 also curtails propidium iodide (PI) influx and increases the viability of Cd-treated cells. The efficacy of EUK-8 as a Cd antidote diminishes gradually when added at a later stage of Cd treatment. EUK-8 blocks Cd transport into cells. It is ineffective in accelerating the efflux of metals from the cells. EUK-8 is a Mn-salen complex. Mn decreases the uptake and cytotoxicity of Cd, while salen perturbs the membrane integrity and increases the uptake and cytotoxicity of Cd. Salen is able to bind Cd, and the Cd-salen complex formed does not perturb the integrity of cell membranes and thus the influx of metal is not enhanced. Our results reveal a differential effect of salen and Mn-salen complex on the transport of Cd with subsequent different levels of cell damage.     

The atrioventricular conduction axis of hearts with isolated ventricular septal defects

We studied the surgical anatomy of 14 hearts with isolated ventricular septal defects and the precise relationship of the atrioventricular conduction axis to their rims. Ten of these hearts were investigated by serial sectioning of their atrioventricular conduction systems. All defects were divided into perimembranous or muscular types as previously suggested by Soto et al. The distinguishing feature of the perimembranous defect was that the central fibrous body formed part of its rim, this fact indicated that the conduction tissue was always to the right of the surgeon's hand when the defect was approached through the right atrium. The precise relationship of the ventricular conduction tissues varied depending upon whether the perimembranous defect extended into the inlet, trabecular or outlet components of the muscular septum. The nonbranching bundle was closest to the septal rim in the inlet and trabecular defects, frequently being buried in a remnant of the interventricular membranous septum. However, in these defects the nonbranching and branching bundles were also found in other specimens remote from the septal crest, yet were carried on the left ventricular aspect of the septum. In perimembranous inlet defects, the penetrating bundle detoured deep into the central fibrous body. In perimembranous outlet defects, the conduction tissues were remote from the septal crest. In contrast to these findings, the conduction tissues were away from the edges of the defects in trabecular and outlet muscular defects. In conclusion, in the perimembranous inlet defect, the placement of the sutures on the annulus of tricuspid valve should be avoided in view of its abnormal long penetrating bundle.     

脑后部可逆性脑病综合征的CT、MRI诊断

目的探讨CT、MRI在诊断脑后部可逆性脑病综合征（PRES）中的价值。方法8例女性PRES患者中6例为孕妇，1例肺癌手术后化疗患者，1例高血压患者，均行MR静脉成像（MRV）、T1WI、T2WI、水抑制序列（FLAIR）成像及扩散加权成像（DWI）；其中2例行CT平扫，5例行增强MRI及三维增强MR血管成像（3DCEMRA）。结果CT示病灶呈低密度，边界不清。8例患者MRV显示脑静脉、静脉窦通畅，无狭窄、异常扩张及血栓形成征象。MRI显示双侧顶枕叶（8例）、基底节区（2例）、额叶（4例）多发异常信号，主要位于双侧顶枕叶皮质下白质内，3例患者皮质亦受累。在T1WI病灶呈等或略低信号，T1WI及FLAIR呈高信号，以FLAIR像显示皮质病变为佳。DWI显示大部分病灶呈等信号，表观扩散系数（ADC）图呈等或高信号。部分病灶DWI及ADC图均表现为高信号。随访MRI显示所有患者病灶范围、数目逐渐变小、减少。5例行增强扫描患者显示病灶呈轻度强化，3D CEMRA显示强化沿双侧大脑前动脉、大脑中动脉及大脑后动脉终末支分布，部分呈“葡萄状”。随访增强扫描显示病灶强化范围及程度逐渐缩小、消失。结论FRES好发于顶枕叶白质，但也可见于基底节、额叶及脑皮质。病变为血管源性水肿，增强T1WI及3D CEMRA显示病灶有可逆性强化。以MRFLAIR及T2WI序列显示病灶最佳。     

The usefulness of the Platelia Candida antigen in a patient with acute lymphocytic leukemia and chronic disseminated candidiasis.

We report a protracted course of disseminated candidiasis due to Candida tropicalis in a 17-year-old man with acute lymphocytic leukemia. Despite adequate antifungal therapy (amphotericin B), C. tropicalis was recovered from biopsy specimens 25 days (skin) and 109 days (kidney) after the first positive blood cultures. While blood cultures became negative for C. tropicalis 11 days after the initiation of treatment, mannanemia persisted and became negative only after 130 days of antifungal therapy. Thus, antigen assays provided indicators of antifungal response. Differential diagnosis was difficult for this patient with the observation of persistent lesions in image studies. With positive results of antigen assays, an invasive procedure might be avoided and preemptive antifungal treatment could be initiated in a timely manner. Anti-mannan antibody remained undetectable up to 164 days after first positive blood culture despite the patient's recovery from neutropenia and recruitment of neutrophils in the tissue (skin).