In vitro megakaryocyte expansion in patients with delayed platelet engraftment after autologous stem cell transplantation

Increasing the number of megakaryocytic cells in stem cell transplants by ex vivo expansion culture may provide an approach to accelerate platelet engraftment after high-dose chemotherapy. However, it is unknown if a relationship exists between the expansion potential of progenitor cells and the time to platelet engraftment in vivo. Therefore, we questioned if those patients who potentially would benefit most from expanded cell supplements are able to generate megakaryocytic cells efficiently in vitro. The in vitro megakaryocyte proliferation was analyzed from 19 leukapheresis samples from a group of multiple myeloma patients who all showed rapid neutrophil engraftment, but varied from 7 to 115 days post-transplant to achieve platelet levels >20x10(9)/l. CD34+ cells were isolated and analyzed for their potential to form megakaryocytic colonies (CFU-Mk) in colony assays and megakaryocytic (CD61+) cells in suspension cultures. The frequency and size of CFU-Mk and the expansion potential of CD61+ cells varied eightfold between individual patients. A similar range was found with CD34+ cells isolated from normal bone marrow (n=9). Rapid platelet engraftment occurred in patients receiving both high or low CFU-Mk doses and with high and low expansion of CD61+ cells. Four patients who experienced prolonged (>3 weeks) thrombocytopenia received low CFU-Mk doses, but the expansion potential was around median values or higher. Therefore, we conclude that the megakaryocyte proliferation is not impaired and that in vitro expansion could increase the number of megakaryocytic cells, although other factors could be more relevant in platelet engraftment in this group of patients.     

Anaesthesia for paediatric cardiac MRI

Background: General anaesthesia (GA) for cardiac magnetic resonance imaging (MRI) in patients with congenital heart disease (CHD) is challenging for the anaesthesiologist.     

Muscular sufficiency, serum protein, enzymes and bioenergetic studies (31-phosphorus magnetic resonance spectroscopy) in chronic malnutrition

Muscle sufficiency was significantly lower in 1336 children with chronic malnutrition of moderate to severe degree. Eighteen children with a chronic moderate degree of malnutrition and 8 well-nourished, age-matched controls were selected for biochemical and 31-phosphorus magnetic resonance spectroscopy (31 -P MRS) studies. The results showed that: (a) serum total protein, albumin, iron, calcium and inorganic phosphate were similar in both groups; (b) serum enzyme levels were significantly increased in the malnourished group; (c) 31-P MRS showed significantly higher means for total ATP, β-ATP, a-ATP and inorganic phosphate for the malnourished compared to the control group. In chronic malnutrition, proteins are maintained by degradation in muscle resulting in release of amino acids and enzymes. 31-P MRS studies showing increases in total ATP, β-ATP and inorganic phosphate and a decrease in phosphocreatine suggest that ATP is maintained at the cost of phosphocreatine.     

Carotid artery stenosis: clinical efficacy of two-dimensional time-of-flight MR angiography.

To assess the clinical efficacy of two-dimensional time-of-flight magnetic resonance (MR) angiography in the evaluation of carotid artery stenosis, a group of patients was evaluated in which 73 vessels were studied with both MR and conventional angiography. Four experienced neuroradiologists each scored both the MR and conventional angiograms in a blinded manner by using a standardized scoring scheme. Comparison of the scores revealed a high degree of correlation. In particular, MR angiography served to discriminate reliably between mildly narrowed and severely narrowed or occluded vessels. Furthermore, severe stenoses were accurately discriminated from occlusions in all cases. MR angiography is a robust and accurate modality for the characterization of carotid artery stenosis. It is useful in conjunction with routine MR imaging of the brain in the evaluation of the patient with suspected carotid arterial disease.     

高效液相色谱法测定血浆中洛美沙星浓度及其在人体内药代动力学

建立了人血浆洛美沙星的反相离子对高效液相色谱测定方法。该法简便易行,精密度好,方法回收率95～102%,日内、日间RSD为2.1～7.8%,血药浓度在0.125～5.012 μg/ml范围内呈线性关系,相关系数0.9998,当S/N=2时,最小检测浓度为25 ng/ml。健康志愿者口服400 mg洛美沙星,药代动力学过程符合一室模型,消除相半衰期为5.5 h。     

Improved methods for isolating cortisol metabolites from neonatal urine

Urine was collected from newborns, children, and adults who had received a tracer dose of [3H] cortisol. The free and different types of conjugated cortisol metabolites were separated by ion-exchange chromatography. A modified Amberlite XAD-2 procedure was used, which enabled quantitative extraction of the extremely polar cortisol metabolites from urine from newborns. Large differences between the ion-exchange chromatographic patterns for neonates and adults were observed. Urine from neonates was shown to contain quantitatively important amounts of an as-yet-unidentified conjugate that was absent from urine from adults. The effects of three different hydrolytic methods on the neonatal steroid conjugates were studied and it was found that the unknown conjugate in urine from the newborn could be hydrolyzed by solvolysis only.     

Theoretical basis for interest in acetylprocainamide and clinical experiences with this new antiarrhythmic agent.

In conclusion, it was the differential responses of slow and rapid acetylators to procainamide therapy that gave the initial clues that acetylprocainamide might be a safer drug than procainamide. So far, the experience with acetylprocainamide has been encouraging.     

Recognizing the empty sella by CT: the infundibulum sign

Inaccuracy in recognizing the empty sella by conventional computed tomography (CT) techniques derives from diverse intrasellar cystic structures that are not distinguished from it. In 23 cases of presumed empty sella, it was observed that the pituitary stalk within the enlarged sella (infundibulum) was demonstrated by thin (1.5 mm) coronal CT sections. ALthough the diagnosis was not proven by conventional studies, the normal appearance of the infundibulum is believed to exclude an intrasellar cyst or tumor as the cause of sellar enlargement. Coronal CT sections with thin slices and intravenous contrast enhancement are recommended when empty sella is to be documented by CT. When the infundibulum is not demonstrated by this technique, CT with intrathecal enhancement may be warranted.