FDA Global Drug Inspections: Surveillance Of Manufacturing Establishments Remains Well Below Pre-COVID-19 Levels.

During the initial phase of the COVID-19 pandemic, the Food and Drug Administration (FDA) halted inspections of most overseas drug manufacturing establishments. Looking at data from the period 2012-22, we observed steep declines in both foreign and domestic inspections in 2020. By 2022, numbers of inspections remained well below prepandemic levels, with a 79 percent decrease in foreign inspections and a 35 percent decline in domestic inspections compared with 2019. There was no corresponding reduction in drug manufacturing or imports. Also, the resources allocated per inspection surged, although the FDA's overall budget and staffing remained steady. Finally, citations rose dramatically, despite all establishments being given advance notice of inspections. The findings of our study underscore the pressing need to explore alternative methods for ensuring drug safety.

ADAR1 Knockout Inhibits Notch1-induced T-ALL in Mice / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of ADAR1 on the occurrence and development of mouse T cell acute lymphoblastic leukemia (T-ALL).</p><p><b>METHODS</b>Lck-Cre; ADAR1lox/lox mice were generated through interbreeding. The lineage-cells of Lck-Cre; ADAR1lox/lox mice and the control were enriched respectively by the means of MACS, and the lin- cells were transfected with retrovirus carrying MSCV-ICN1-IRES-GFP fusion gene. Then the transfection efficiency was detected by the means of FACS, and the same number of GFP+ cells were transplanted into lethally irradiated recipient mice to observe the survival of mice in 2 recipient group after transplantation.</p><p><b>RESULTS</b>T cell-specific knockout ADAR1 mice were generated, and Notch1-induced T-ALL mouse model was established successfully. The leukemia with T-ALL characteristics occured in the mice of control group, but did not in the ADAR1 kmockout mice after transplantation.</p><p><b>CONCLUSIONS</b>ADAR1 plays a key role in the incidence and development of Notch1-induced T-ALL.</p>

Expression of CD48 as a live marker to distinguish division of hematopoietic stem cells / 中国实验血液学杂志

Hematopoietic stem cells are capable of self-renewal or differentiation when they divide. Three types of cell divisions exist. A dividing stem cell may generate 2 new stem cells (symmetrical renewal division), or 2 differentiating cells (symmetrical differentiation division), or 1 cell of each type (asymmetrical division). This study was aimed to explore an efficient and stable method to distinguish the way of cell division in hematopoietic stem cells. Previous studies showed that the distribution of Numb in a cell could be used to distinguish the type of cell division in various kinds of cells. Therefore, the distribution of Numb protein was detected by immunofluorescence in mitotic CD48(-)CD150(+)LSK cells of mice exploring the relationship between Numb protein and centrosomes. Since CD48 positive marks the HSC that have lost the ability to reconstitute the blood system in mice, CD48 marker could be used to distinguish cell fate decision between self-renewal and differentiation as a living marker. In this study, the CD48(-)CD150(+)LSK cells were sorted from bone marrow cells of mice and the cells were directly labeled with Alexa Fluor (AF) 488-conjugated anti-CD48 antibody in living cultures. After 3 days, the percentage of AF488(+) cells was evaluated under microscope and by FACS. Then colony forming cell assay (CFC) was performed and the ability of cell proliferation were compared between AF488(+) and AF488(-) cells. The results showed that Numb could be used to distinguish different cell division types of hematopoietic stem cells, which was symmetrically or asymmetrically segregated in mitotic CD48(-)CD150(+)LSK cells. The self-labeled fluorochrome could be detected both by FACS as well as microscope. There were about 40% AF488(+) cells after 3 day-cultures in medium titrated with self-labeled AF 488-conjugated anti-CD48 antibody, and the results were consistent between confocal fluorescence microscopy and flow cytometry analysis. The colony forming ability of AF488(+) cells was significantly higher than that of AF488(-) cells (P < 0.05). The proliferation ability of AF488(-) cells was also significantly higher than AF488(+) cells (P < 0.05). It is concluded that the expression of CD48 can distinguish cell division of hematopoietic stem cells and can be used as a live marker for the loss of stemness. In comparison with the Numb protein staining, this method can be used in living cells, thus provides greater convenience for subsequent cell culture studies and cell transplantation experiments.

Commonly used cre transgenic mice and their applications in hematopoietic system / 中国实验血液学杂志

Cre-lox recombination system consists of two elements: Cre recombinase enzyme and lox sites. Cre recombinase can recombine the lox site sequences by specifically detecting and cutting them. The direction and position of lox sites determine the functional effects of Cre enzyme such as deletion, inversion or chromosomal translocation. The hematopoietic system of mouse consists of multi-lineages and various developmental stage hematopoietic cells that are differentiated from hematopoietic stem cells (hematopoietic stem cells, HSC). The hematopoietic stem cells are maintained in the bone marrow microenvironment (niche). Currently, a variety of floxed conditional-knockout mice, recognized by Cre-lox recombination system, are used for the study of the hematopoietic system. This review summarizes the commonly used Cre transgenic mice and their applications in the study of hematopoietic system.

A new class of structurally rigid tricyclic chiral secondary amine organocatalyst: highly enantioselective organocatalytic Michael addition of aldehydes to vinyl sulfones.

A new class of chiral secondary amine organocatalyst was rationally designed as an efficient catalyst to catalyze the elusive Michael addition of aldehydes to vinyl sulfones. High yield and excellent enantioselectivities could be obtained at room temperature without having to resort to high catalyst loading, anhydrous solvents, and low temperatures. Efficient control of enamine conformation and face shielding as well as the rigid nature of the tricyclic skeleton, with an inherent chiral pocket, provide a well-organized chiral environment to effect this elusive reaction efficiently.

Chemzymes: a new class of structurally rigid tricyclic amphibian organocatalyst inspired by natural product.

A new class of structurally rigid tricyclic amphibian chiral catalyst was rationally designed based on the hexahydropyrrolo[2,3-b]indole skeleton as a new type of chemzyme. This new type of chemzyme possesses a structurally rigid tricyclic skeleton and a chiral pocket which provides a well-organized chiral environment for asymmetric induction, as well as a hydrophobic pocket to enable organocatalytic reactions to proceed smoothly both in organic solvents and in water.