Collecting and evaluating convalescent plasma for COVID-19 treatment: why and how?

Plasma provided by COVID-19 convalescent patients may provide therapeutic relief as the number of COVID-19 cases escalates steeply worldwide. Prior findings in various viral respiratory diseases including SARS-CoV-related pneumonia suggest that convalescent plasma can reduce mortality, although formal proof of efficacy is still lacking. By reducing viral spread early on, such an approach may possibly downplay subsequent immunopathology. Identifying, collecting, qualifying and preparing plasma from convalescent patients with adequate SARS-CoV-2-neutralizing Ab titres in an acute crisis setting may be challenging, although well within the remit of most blood establishments. Careful clinical evaluation should allow to quickly establish whether such passive immunotherapy, administered at early phases of the disease in patients at high risk of deleterious evolution, may reduce the frequency of patient deterioration, and thereby COVID-19 mortality.     

Preliminary evaluation of vitiligo using in vivo reflectance confocal microscopy

BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.     

Role of blast cell immunophenotyping for the diagnosis and prognosis of acute myeloid leukemia.

Bone marrow blast cell antigen expression from 86 patients with de novo acute myeloid leukemias (AML) was studied and correlated with FAB classification and clinical outcome. Among a panel of 14 monoclonal antibodies routinely used for the diagnosis of acute leukemias we studied the expression of six antibodies (CD13, CD15, VIM2, CD33, CD14, CD34) of the granulomonocytic lineage and found that some of them were useful for diagnosis and/or prognosis. For FAB subclassification of AML, the CD13 or VIM2 antigen expression was of no benefit. Monocytic leukemias (M4 + M5PD + M5WD) more frequently expressed CD34 antigen (28/31) than granulocytic (M1 + M2 + M3) subtypes (33/53) (P < 0.01). Finally, the most striking differences were found with CD14 antigen expression: CD14 antigen was more frequently expressed in M4 + M5 leukemias (21/31) than in M1 + M2 + M3 subtypes (12/33) (P < 0.01). The mean percentage of CD14 positive blast cells was accordingly higher in monocytic leukemias than in granulocytic leukemias and the difference was highly significant (P < 0.0001). The CD15 antigen was more frequently expressed in differentiated leukemias (M2 + M3 + M4 + M5WD) (35/44) than in poorly differentiated forms (M1 + M5PD) (17/37) (P < 0.001). The statistical difference was higher when the mean percentage of CD15 positive blast cells were compared (P < 0.0003). Moreover these latter percentages were different in M1 and M2 subtypes (P < 0.003). The blast cell expression of CD13, CD14, CD15 or CD33 was not predictive of the length of CR or survival. Moreover, our results support previously published findings suggesting a longer overall survival duration for patients whose leukemic cells do not express the CD34 antigen (P < 0.01). We also confirm that patients with the more differentiated subtypes of AML (CD13-, CD34+) tend to survive longer than patients with the less differentiated subtypes of AML (CD13-, CD34+) (P < 0.001).     

Hemorrhagic and nonhemorrhagic brain lesions: evaluation with 0.35-T fast MR imaging

Two fast magnetic resonance (MR) imaging techniques, advanced Fourier and partial-flip imaging, were used at 0.35 T to examine 21 patients with suspected intracranial lesions; the results were quantitatively compared with a conventional spin-echo study. Both of the fast MR techniques yielded a fourfold reduction in imaging time per section. The advanced Fourier sequence showed contrast that was identical to the conventional spin-echo study with signal-to-noise ratios of 58% and 57% for the first and second echoes, respectively. The partial-flip sequence showed a contrast of 109% and 57% for lesions versus substantia alba, and 107% and 78% for substantia grisea versus substantia alba relative to the first and second echoes of the conventional spin-echo study. The partial-flip sequence was particularly sensitive to magnetic susceptibility; this produced artifacts that may undermine the usefulness of partial flip for routine screening in certain parts of the brain. However, this susceptibility significantly improved the detection of intracranial hemorrhage when compared with the spin-echo sequence, particularly when combined with phase mapping of the partial-flip study.     

高效液相色谱法测定右旋儿茶素血浆浓度及药代动力学参数

本文建立了体液中右旋儿茶素的RP-HPLC测定方法。采用C_(18)键合相硅胶为填料的固相提取柱进行样品预处理,右旋儿茶素的提取回收率为79.8%.应用二极管阵列检测器对色谱峰纯度进行鉴定。该法精密度好,方法回收率近100%,日内、日间的变异系数为2.4～5.6%,血浓69.6～1160 ng/ml范围内呈线性关系,r=0.9993。家兔静注右旋儿茶素18mg/kg,其药代动力学过程符合二室模型,分布相半衰期为0.129 h,消除相半衰期为1.19h。