Intracellular pattern of cytosolic Ca2+ changes during adhesion and multiple phagocytosis in human neutrophils. Dynamics of intracellular Ca2+ stores

The subcellular pattern of cytosolic free Ca2+ ([Ca2+]i) changes in human polymorphonuclear neutrophils (PMNs) was studied using imaging of fura-2 fluorescence (time resolution 12.5 ratios/s) to determine whether PMNs could obtain directional information from the [Ca2+]i signal. [Ca2+]i changes were observed during initial adherence, the subsequent chemotactic movement, and the phagocytosis of opsonized yeast particles. Initial adherence was followed by a rapid increase in [Ca2+]i (from 90 +/- 10 to 290 +/- 40 nmol/L in 6.5 +/- 2.5 seconds; +/- SEM, n = 10), apparently homogeneously distributed over the entire cytoplasm, which preceded the spreading of the PMNs. [Ca2+]i increases after the contact of the PMNs with yeast particles were of lower mean amplitude; [Ca2+]i increased simultaneously throughout the cytosol. In the absence of extracellular Ca2+, multiple phagocytotic events could proceed normally without a mandatory [Ca2+]i transient. In PMNs polarized on phagocytosis, gradients in [Ca2+]i could be observed. [Ca2+]i was more elevated in the periphagosomal area than in the remaining parts. Taken together, these data show that [Ca2+]i waves do not provide the neutrophil with directional information during chemotaxis and phagocytosis. Sustained small inhomogeneity of [Ca2+]i levels are consistent with a proposed redistribution of releasable Ca2+ stores on phagocytosis.     

A survey of the incidence of Miltenberger antibodies among Hong Kong Chinese blood donors

BACKGROUND: The ready availability of red cells of the Miltenberger (Mi) class III phenotype (6.28%) prompted the study of Mi antibodies among Chinese blood donors in Hong Kong, 98 percent of whom are descended from inhabitants of Guangdong Province in southern China. STUDY DESIGN AND METHODS: Red cells of the Mi class III phenotype were used to conduct a survey of the frequency of Miltenberger antibodies in 56,161 random Chinese blood donors, over a period of 12 months, using a microplate technique. RESULTS: Sera from 32 donors (0.057%) were found to contain Mi antibodies: sera from 22 contained anti-Mur + Hut; sera from 4 contained anti-Vw + Mur + Hut; sera from 4 had monospecific anti- Mur; and sera from 2 had monospecific anti-Hil. The immunoglobulin isotypes of 24 sera were mixtures of IgM and IgG, 4 were pure IgM, and 4 were pure IgG. CONCLUSION: The majority of Mi antibodies detected were naturally occurring. This survey proved useful for mass screening of random donors for the procurement of valuable Mi antisera.     

Spinal Muscular Atrophy: From Gene Discovery to Clinical Trials

Spinal muscular atrophy (SMA) is a common neuromuscular disorder with autosomal recessive inheritance, resulting in the degeneration of motor neurons. The incidence of the disease has been estimated at 1 in 6000–10,000 newborns with a carrier frequency of 1 in 40–60. SMA is caused by mutations of the SMN1 gene, located on chromosome 5q13. The gene product, survival motor neuron (SMN) plays critical roles in a variety of cellular activities. SMN2, a homologue of SMN1, is retained in all SMA patients and generates low levels of SMN, but does not compensate for the mutated SMN1. Genetic analysis demonstrates the presence of homozygous deletion of SMN1 in most patients, and allows screening of heterozygous carriers in affected families. Considering high incidence of carrier frequency in SMA, population‐wide newborn and carrier screening has been proposed. Although no effective treatment is currently available, some treatment strategies have already been developed based on the molecular pathophysiology of this disease. Current treatment strategies can be classified into three major groups: SMN2‐targeting, SMN1‐introduction, and non‐SMN targeting. Here, we provide a comprehensive and up‐to‐date review integrating advances in molecular pathophysiology and diagnostic testing with therapeutic developments for this disease including promising candidates from recent clinical trials.     

Prospective, randomized trial of 5-fluorouracil, leucovorin, doxorubicin, and cyclophosphamide chemotherapy in combination with the interleukin-3/granulocyte-macrophage colony-stimulating factor (GM-CSF) fusion protein (PIXY321) versus GM-CSF in patients with advanced breast cancer

We conducted a prospective randomized trial to evaluate the ability of the interleukin-3/granulocyte-macrophage colony-stimulating factor (GM- CSF) fusion protein, PIXY321, to ameliorate cumulative thrombocytopenia after multiple cycles of 5-fluorouracil, leucovorin, doxorubicin, cyclophosphamide (FLAC) chemotherapy compared with GM-CSF in patients with advanced breast cancer. Fifty-three patients were randomized to receive either PIXY321. 375 microg/m2 twice a day subcutaneously, or GM- CSF, 250 microg/m2 daily subcutaneously after FLAC chemotherapy. PIXY321 was less well tolerated than GM-CSF, with more patients developing chills and local skin reactions and more patients stopping PIXY321 due to intolerance. While no difference in the neutrophil nadirs was seen with the two cytokines, the duration of the absolute neutrophil count less than 1,000/muL for all cycles was significantly longer with PIXY321 than with GM-CSF. Fifty percent of patients treated with multiple cycles of FLAC chemotherapy on both study arms developed dose-limiting thrombocytopenia. No differences in platelet nadirs, duration of thrombocytopenia, or need for platelet transfusions were observed with PIXY321 versus GM-CSF. The average delivered doses of FLAC chemotherapy were somewhat higher in the GM-CSF study arm. PIXY321 was not superior to GM-CSF in ameliorating the cumulative thrombocytopenia observed with multiple cycles of FLAC chemotherapy and was less well tolerated.     

头孢类抗生素在水溶液中的聚合

对7种头孢类抗生素:头孢唑肟钠(CZX),头孢噻肟钠(CTX),头孢曲松钠(CTRX),头孢替安(CTM),头孢孟多钠(CMD),头孢唑啉钠(CZL)和头孢噻吩钠(CLT)在水溶液中的聚合行为进行了研究。将头孢类抗生素的水溶液(10%～50%)在DEAE-Sephadex A-25离子交换色谱柱上,用含NaCl 0.2～3.0mol·L^-1的磷酸盐缓冲液(pH 7.4～9.4),在室温下进行线性梯度洗脱,在260nm监测,收集各流分。用CD,FAB-MS和NMR等确证洗脱图谱中峰值对应的化合物,发现CMD,CZL,CLT,CTRX和CTM在实验条件下没有形成聚合物,CTX和CZX的水溶液在室温下放置几天可形成二聚物,表明分子中不含自由氨基或含有氨基,但空间或电荷位阻大时,没有聚合物形成。形成的二聚物是由于自由氨基向核进攻另一分子的β-内酰胺环,引起分子间氨解的结果。     

Discrepancy between computed tomography coronary angiography and selective coronary angiography in the pre‐stenting assessment of coronary lesion length

We aimed to compare the lesion length measured on computed tomography coronary angiography (CT‐CA) with the selective coronary angiography (SCA) lesion length measured on quantitative coronary angiography (QCA). Compared with SCA, CT‐CA has the advantage of showing the lumen and the atherosclerotic plaque in the arterial wall. This prospective observational study involved 44 coronary lesions. Computed tomography coronary angiography was carried out with an electrocardiogram‐gated 16‐slice CT before percutaneous coronary intervention. A cardiologist and a radiologist measured CT lesion lengths in consensus, whereas an interventional cardiologist carried out QCA to obtain SCA lesion lengths independently. The median difference of (CT lesion length − SCA lesion length) was 9.84 mm (95%CI: [7.26, 13.34]). The median difference of (stent length − SCA lesion length) was 7.68 mm (95%CI: [6.29, 9.26]); the median difference of (stent length − CT length) was −2.63 mm (95%CI: [−5.80, 0.05]). The mean ratio of stent length to SCA lesion length was 2.07 (95%CI: [1.83, 2.30]). The mean ratio of stent length to CT‐CA lesion length was 0.97 (95%CI: [0.83, 1.11]). In the subgroup of drug‐eluting stents (17 lesions), the median difference of (stent length − SCA lesion length) was 9.76 mm (95%CI: [6.59, 13.28]); the median difference of (stent length − CT length) was −5.2 mm (95%CI: [−11, 0.5]). The mean ratio of stent length to CT‐CA lesion length was 0.93 (95%CI: [0.68, 1.17]). Computed tomography lesion length was substantially longer than SCA lesion length measured by QCA. Routine practice of choosing stent length based on QCA may underestimate the actual length of target lesion. This may lead to incomplete coverage of the target lesion, particularly when drug‐eluting stents are used.     

Diagnostic accuracy of 16‐slice CT coronary angiography in the evaluation of coronary artery disease

Multislice CT coronary angiography (CT‐CA) has emerged as a potential imaging method for coronary artery disease. This study aimed to ascertain the accuracy of 16‐slice CT in the diagnosis of significant coronary stenosis (≥50% reduction of lumen diameter). This mixed retrospective/prospective observational study compared 95 paired 16‐slice CT‐CA and fluoroscopic coronary angiography (FCA) sets. A cardiologist and a radiologist blinded to the FCA findings evaluated CT‐CA images independently by visual estimation. Disagreement between these reporters was arbitrated by a third CT reporter (a cardiologist). A separate cardiologist blinded to CT‐CA findings assessed FCA by visual estimation. Of 1161 coronary segments assessable on FCA, 1103 segments (95%) were assessable on CT‐CA. The CT‐CA correctly diagnosed 147/180 segments with significant stenoses (sensitivity = 82%) and correctly identified 874/923 coronary segments without significant stenoses (specificity = 95%). The positive and negative predictive values of CT‐CA in the diagnosis of coronary segment with significant stenosis were 75 and 96%, respectively. On patient‐based analysis, CT‐CA correctly identified all 68 studies with at least one vessel with significant stenosis (sensitivity = 100%; specificity = 83%). The positive and negative predictive values of CT‐CA in identifying patients with significant coronary stenosis were 94 and 100%, respectively. The 16‐slice CT‐CA showed moderately good sensitivity but very high specificity and negative predictive value in the diagnosis of significant coronary stenosis. The CT‐CA would appear to be a useful ‘rule‐out’ test for patients with low‐risk profile for ischaemic heart disease.     

Magnesium in the prophylaxis of migraine-a double-blind, placebo-controlled study

The migraine prophylactic effect of 10 mmol magnesium twice-daily has been evaluated in a multicentre, prospective, randomized, double-blind, placebo-controlled study. Patients with two to six migraine attacks per month without aura, and history of migraine of at least 2 years, were included. A 4-week baseline period without medication was followed by 12 weeks of treatment with magnesium or placebo. The primary efficacy end-point was a reduction of at least 50% in intensity or duration of migraine attacks in hours at the end of the 12 weeks of treatment compared to baseline. With a calculated total sample size of 150 patients, an interim analysis was planned after completing treatment of at least 60 patients, which in fact was performed with 69 patients (64F, 5M), aged 18–64 years. Of these, 35 had received magnesium and 34 placebo. The number of responders was 1 in each group (28.6% under magnesium and 29.4% under placebo). As determined in the study protocol, this was a major reason to discontinue the trial. With regard to the number of migraine days or migraine attacks there was no benefit with magnesium compared to placebo. There were no centre-specific differences, and the final assessments of treatment efficacy by the doctor and patient were largely equivocal. With respect to tolerability and safety, 45.7% of patients in the magnesium group reported primarily mild adverse' events like soft stool and diarrhoea in contrast to 23.5% in the placebo group.