Twin embolization syndrome: prenatal sonographic detection and significance

Twin embolization syndrome (TES) is a complication of monozygotic twinning following in utero demise of the co-twin. Passage of thromboplastic material into the circulation of the surviving twin results in ischemic structural defects of the central nervous system, gastrointestinal tract, and genitourinary system. In six cases of this rare abnormality, sonographically normal fetuses subsequently demonstrated ventriculomegaly, porencephaly, cerebral atrophy, or microcephaly following demise of the co-twin. Extracranial abnormalities included small bowel atresia (two cases) and renal cortical necrosis (one case). Surviving twins all had neurodevelopmental delay at follow-up. Two fetuses were aborted because of sonographically apparent, progressively severe brain abnormality. The lone survivor of a dizygotic triplet gestation was normal, despite sonographic findings of TES in the co-triplets. Because of poor outcome, prenatal sonographic diagnosis of TES may influence antenatal or neonatal management of the surviving monozygous twin. Recognition of TES may permit accurate postnatal counseling of prognosis and recurrence risks.     

SMALL JOINT SYNOVTTIS IN RHEUMATOID ARTHRITIS: SHOULD IT BE ASSESSED SEPARATELY?

In the assessment of disease activity in rheumatoid arthritis(RA) small joint synovitis is traditionally included only asa component of active, tender or swollen joint counts. By contrast,in the assessment of disease damage in RA, the X-ray score ofhands and feet represents one of the most common parametersused and is regarded as a major indicator of outcome. Data presentedin this study lead us to hypothesize that the small joints requireseparate assessment in any study of disease activity or outcomein RA: (i) there is clear evidence that small joint synovitisoften occurs in the absence of an abnormal acute phase response(ESR or C-reactive protein) and (ii) measured synovitis is anindividual (PIP) joint has been shown to be reliable and tobe related to subsequent X-ray changes in the same joint. Ourfindings show that, in a study of a treatment of RA, it is quitepossible for disease activity measures to appear controlledwhile inflammation continues in the small joints causing radiologicaldamage. This radiological damage is reflected as an adverseoutcome. Hence the paradox of improving disease activity butnot outcome. We argue that small joint inflammation and damageshould be recognized as one aspect of the RA disease processoffering unique information and as such should be assessed independently. KEY WORDS: Rheumatoid arthritis, Disease activity, Small joint synovitis, X-ray     

Localization of dopamine and its relation to the growth hormone producing cells in the central nervous system of the snail Lymnaea stagnalis

Summary The distribution of dopamine in the central nervous system of the pond snail Lymnaea stagnalis was investigated by using immunocytochemistry and HPLC measurements. With both methods it was demonstrated that dopamine is predominantly present in the cerebral and pedal ganglia. The dopamine-immunoreactivity was mainly observed in nerve-fibers in the neuropile of the ganglia. Relatively few dopamine-immunopositive cell bodies (diameters 10–30 m) were found. A large cell in the right pedal ganglion (the so-called RPeD1) stained positively with the dopamine antibody. It has previously been demonstrated that the growth hormone producing cells (GHCs) possess dopamine receptors on their cell bodies. However, dopamine-immunopositive fibers were observed only in the vicinity of the GHC nerve-endings and not close to the GHC cell bodies.     

周期性机械牵张刺激对C_2C_(12)小鼠成肌细胞增殖和有氧代谢能力的影响

目的探讨不同频率牵张刺激对C_2C_(12)小鼠成肌细胞增殖及细胞有氧代谢能力的影响。方法采用Flexercell细胞应力加载装置对体外培养的C_2C_(12)成肌细胞分别加载1、2 Hz不同频率的牵张刺激,牵张幅度为15%,牵张时长为2 h/d,连续进行4 d。以静置培养的C_2C_(12)成肌细胞作为对照组。实验期间通过倒置相差显微镜观察细胞生长状态,利用CCK-8试剂盒测定细胞增殖情况。实验结束后,分别收取各组细胞,经胰酶消化处理,然后利用荧光探针,通过能量代谢设备检测细胞耗氧量比率。结果细胞经机械牵张刺激后,显微镜下细胞形态为典型的长梭形,排列呈现一定方向性,与牵张刺激方向平行,生长状况良好;与对照组细胞相比,1、2 Hz频率牵张刺激均可显著促进细胞增殖(P0.05),且在第3、4 d,1 Hz实验组的增殖情况优于2 Hz实验组;实验组与对照组细胞耗氧量比率均有增加,但各组之间并无显著差异(P0.05)。结论周期性机械牵张刺激能有效促进C_2C_(12)小鼠成肌细胞增殖,且与牵张刺激的频率有关,其中1 Hz的牵张频率最佳,但牵张刺激对C_2C_(12)小鼠成肌细胞的有氧代谢能力无明显影响。     

Partial flip angle MR imaging

Theoretical analysis predicts that performing magnetic resonance (MR) imaging with partial (less than 90 degrees) flip angles can reduce imaging times two- to fourfold when lesions with elevated T1 values are being examined. This time savings occurs because repetition time (TR) is reduced when imaging is performed with partial flips. Partial flip MR imaging can also improve signal-to-noise ratio (S/N) in fast body imaging. For this study, analytical tools were used to predict image contrast and S/N for short TR, partial flip sequences. Experimental implementation of the short TR, partial flip sequences that analytical work had predicted would be optimal supported the analytical predictions and demonstrated their validity. Partial flip MR imaging is applicable to reducing imaging time only when the ratio of signal differences to noise exceeds threshold values in conventional MR images. Partial flip sequences can be used to advantage in MR imaging of both the head and the body, and the observed effects are predictable through theoretical analysis.     

Deficiency of methylthioadenosine phosphorylase in human leukemic cells in vivo

Cells from 20 patients with leukemia and 9 with solid tumors were assayed for the enzyme methylthioadenosine phosphorylase, which function in both purine and polyamine metabolism in rapidly dividing cells. As determined by autoradiography of viable cells, and by direct enzymatic analysis, samples from one individual with pre-T-cell acute lymphoblastic leukemia and one with common acute lymphoblastic leukemia were methylthioadenosine phosphorylase deficient. In contrast, other leukemias of similar antigenic phenotype, as well as normal peripheral blood lymphocytes, thymic lymphocytes, and normal bone marrow cells, had substantial methylthioadenosine phosphorylase activity. This evidence suggests that the complete absence of methylthioadenosine phosphorylase distinguishes some leukemic cells in vivo from their nonmalignant counterparts.     

Improved control of image optical density with low-dose digital and conventional radiography in bedside imaging

The technical and diagnostic performance of simultaneously acquired low-dose (44% of standard dose) storage-phosphor digital radiographs (system resolution = 0.2 mm, 10 bits) were compared with those of standard-dose conventional bedside radiographs of the chest in 32 patients. The mean optical density (OD) of the lungs (800 measurements) was closer to the ideal density with digital radiography (1.45 OD +/- 0.20 [standard deviation] vs 1.75 OD +/- 0.53) and was less often outside the usable range (2.5% vs 42.5%). Receiver operating characteristic analysis for detection of simulated nodules and monitoring devices (nine readers, 4,608 observations) showed that digital radiography was superior to conventional radiography (P less than .05) for four of the nine readers and equivalent to conventional radiography for five readers. The authors concluded that digital radiography produces more consistent and ideal image density and performs at least as well as conventional radiography under phantom test conditions.     

Evaluation of three oral rehydration solutions designed for use in developed communities

One hundred and sixteen children (less than 2 years old) admitted to a London hospital with acute gastroenteritis were randomized to receive either an oral rehydration solution (ORS) with low sodium and high glucose concentration (Na+ 35, glucose 200 mmol/L), an ORS with a high sodium but low glucose concentration (Na+ 60, glucose 111 mmol/L), or an ORS containing glycine and a glucose polymer (Na+ 50, glucose 50, glycine 50 mmol/L). Clinical, biochemical and haematological features of the three groups were similar on admission. Rotavirus was common (31%); the majority of children had minimal dehydration or acid-base disturbance. The clinical outcome, including ORS intake, prevention of dehydration, rehydration, and duration of hospital stay was similar in the three treatment groups. All initial electrolyte abnormalities were corrected; no child developed hypernatraemia or hyponatraemia. At 24 h, the mean serum urea was higher in those who received the ORS containing glycine than in other groups, and it had not fallen significantly since admission. Eighteen per cent of children had carbohydrate intolerance: four children with greater than or equal to 2% reducing substances in their stool had all received ORS with a high glucose content and had numerous watery green stools containing rotavirus. All ORS solutions were safe and effective for rehydration and correction of biochemical abnormalities, however carbohydrate intolerance was more prevalent in children who received the ORS with a high glucose content.