Results Of Experiments In Mice Research Articles

Mitochondrial aggregation caused by cytochalasin B compromises the efficiency and safety of three-parent embryo.

It is widely accepted that cytochalasin B (CB) is required in enucleation of the oocyte in order to stabilize the cytoplasm. However, CB treatment results in the uneven distribution of mitochondria, with aggregation towards the nucleus, which might compromise the efficiency and safety of a three-parent embryo. Here, we demonstrated that CB treatment affected mitochondrial dynamics, spindle morphology and mitochondrial DNA carryover in a concentration-dependent manner. Our results showed that mouse oocytes treated with over 1 μg/ml CB exhibited a more aggregated pattern of mitochondria and diminished filamentous actin expression. Abnormal fission of mitochondria together with changes in spindle morphology increased as CB concentration escalated. Based on the results of mouse experiments, we further revealed the practical value of these findings in human oocytes. Chip-based digital PCR and pyrosequencing revealed that the mitochondrial carryover in reconstituted human embryos was significantly reduced by modifying the concentration of CB from the standard 5 μg/ml to 1 μg/ml before spindle transfer and pronuclear transfer. In conclusion, our findings provide an optimal manipulation for improving the efficiency and safety of mitochondrial replacement therapy.

Epidemic of wild-origin H1NX avian influenza viruses in Anhui, China

BackgroundAs the natural hosts of avian influenza viruses (AIVs), aquatic and migratory birds provide a gene pool for genetic transfer among species and across species, forming transient “genome constellations.” This work describes the phylogenetic dynamics of H1NX based on the complete molecular characterization of eight genes of viruses that were collected from 2014 to 2015 in Anhui Province, China.MethodsHemagglutination and hemagglutination inhibition tests were used to determine the hemagglutination (HA) activity of the HA subtypes. The entire genomes of the viruses were sequenced on an ABI PRISM 3500xl DNA Analyzer. The sequences were genetically analysed to study their genetic evolution using DNASTAR and MEGA 6. The pathogenic effects of the viruses were evaluated using mouse infection models.ResultsSeven strains of the H1 subtype avian influenza virus were isolated. Phylogenetic analysis indicated natural recombination of the H1 influenza viruses between the Eurasian lineage and the North American lineage. Some genes had high sequence identity with A/bean goose/Korea/220/2011(H9N2), which is a typical case involving viral reassortment between the Eurasian lineage and the North American lineage. The results of infection experiments in mice showed that the viruses could acquire the ability to multiply in mouse respiratory organs without adaptation.ConclusionsThese findings suggest that continued surveillance of wild birds, particularly migratory birds, is important to provide early warning of possible H1 influenza epidemics and to understand the ecology of the virus.

Murine "model" monotheism: an iconoclast at the altar of mouse.

Many use mice for contemporary cardiovascular research, as we should, given the power of the genetic and other tools developed to permit rigorous mechanistic experimentation in this species. We must remain mindful, nonetheless, of the reasons why the results of mouse experiments may not extrapolate readily to human disease. Large gaps separate our mouse experiments and clinical conditions. The differences arise from the genetic homogeneity of inbred mouse strains used in experimentation, the restricted exposure of mice to many microbes and a more monotonous microbiome in mice than in free-living rodents and humans, lack of comorbidities, focus on youthful mice and exaggerated experimental conditions contrived to speed up studies, and the lack of congruence between many experimental “models” and human cardiovascular conditions. We must and should continue to mine studies on mice for the incredibly valuable mechanistic insight they provide. Yet, we as a community could consider more carefully some of the barriers to glib extrapolation of the results of experiments in mice to human disease. > These experimental results in mice suggest that X is a promising novel target for the treatment of human cardiovascular disease (A paraphrase of the concluding sentence of many contemporary cardiovascular research papers). Most use mice. We must use mice for much contemporary cardiovascular experimentation. Yet, we must not succumb to group think about the ready translatability of our experimental results to the results obtained in the clinic. Although many millennia of evolution separate them from humans,1 mice provide incredibly valuable tools for biomedical investigation. In particular, the availability of inbred strains and the development of ever more powerful techniques for sophisticated genetic manipulation allow reductionist experiments of increasing complexity, sophistication, and rigor. Nonetheless, the primacy of mice as experimental animals for cardiovascular research during the past decades may have fostered a tendency to …

Murine Responses to Endotoxin: Another Dirty Little Secret?

For over a century, clinicians and investigators have injected bacterial endotoxins (lipopolysaccharides, LPS) into the veins of animals. Remarkably, some vertebrates (humans, horses, rabbits) are as much as 100,000-fold more likely to succumb to an intravenous dose of LPS than are others (baboons, mice, rats, chickens). With the recent triumph of the laboratory mouse as the major experimental animal model for infectious diseases in humans, the striking difference between human and murine sensitivity to LPS toxicity seems to have become a “dirty little secret” of innate immunology, just as Janeway’s clue to the importance of innate immunity--the potency of adjuvants—was long ignored by students of B and T cells (1). Like many other immunological differences between these species (2), the possibility that results of experiments in mice using LPS and other stimulatory microbial molecules might not apply to humans has been infrequently acknowledged. Now Warren and Cavaillon have called attention to this issue by studying it (3). Their conclusion – that the key factor(s) that account for the striking difference in sensitivity to endotoxin infusion are found in serum, not host cells – should help us think more clearly about many mouse models of human disease. Their results also raise the interesting possibility that these factors might be identified and harnessed to dampen human responses to bacterial diseases.

Ultraflexible vesicles, Transfersomes, have an extremely low pore penetration resistance and transport therapeutic amounts of insulin across the intact mammalian skin

New vehicles for the non-invasive delivery of agents are introduced. These carriers can transport pharmacological agents, including large polypeptides, through the permeability barriers, such as the intact skin. This capability depends on the self-regulating carrier deformability which exceeds that of the related but not optimized lipid aggregates by several orders of magnitude. Conventional lipid suspensions, such as standard liposomes or mixed lipid micelles, do not mediate a systemic biological effect upon epicutaneous applications. In contrast to this, the properly devised adaptable carriers, when administered on the intact skin, transport therapeutic amounts of biogenic molecules into the body. This process can be nearly as efficient as an injection needle, as seen from the results of experiments in mice and humans with the insulin-carrying vesicles. The carrier-mediated transcutaneous insulin delivery is unlikely to involve shunts, lesions or other types of skin damage. Rather than this, insulin is inferred to be transported into the body between the intact skin cells with a bio-efficiency of at least 50% of the s.c. dose action.

Studies on the 2,4-Diamino-6-Substituted Quinazolines

This report summarizes the results of appraisals of various activities of CI-679 (a 2,4-diamino-6-amino-substituted quinazoline) in rhesus monkeys infected with the Ro and Ro/PM strains of Plasmodium cynomolgi. In subjects inoculated with sporozoites, CI-679, administered in appropriate schedules in doses up to and including the maximum tolerated level, neither prevented development of infections with these strains nor cured those already established. Although these evaluations showed that CI-679 was devoid of activity against both early and late tissue schizonts, they indicated that this compound had significant blood schizonticidal activity and suggested that such activity was much greater in infections with the Ro strain than in those with the Ro/PM strain. This latter suggestion, contrary to results of earlier experiments in mice infected with Plasmodium berghei, led to studies of the activities of CI-679 in trophozoite-induced infections. These showed that the total course dose of CI-679 required for cure of previously untreated infections with the Ro/PM strain was tenfold that required for cure of comparable infections with the Ro strain. They also showed that infections with either strain, treated previously with subcurative doses, were often not cured by doses of CI-679 that eradicated previously untreated infections regularly. Subsequent studies showed that emergency of parasites resistant to CI-679 was responsible for these retreatment failures and that this resistance was retained through mosquito transfer.

Interaction of influenza virus with leukocytes and its effect on phagocytosis.

Influenza complicated by bacterial pneumonia is probably the best known example of a viral infection that increases the susceptibility of the host to bacterial disease, an example for which there is both clinical [1] and experimental documentation [2-5]. Two mechanisms are recognized as important in the heightened susceptibility. First, viral lesions of the respiratory epithelium [1] may impair clearance of bacteria by the mucociliary apparatus and facilitate direct invasion by the bacteria; results of experiments in mice, however, led Harford and Hamlin [6] to question the nature and the significance of lesions of the bronchial epithelium. Second, edema of the lung may develop. Edema may promote bacterial multiplication and indirectly impair phagocytosis by diluting the exudate that forms as an antibacterial defense [2, 3, 7]. In vitro studies with guinea pig polymorphonuclear leukocytes (PMN) [8-10] suggest that a third factor may be important, namely, a direct antiphagocytic action of the virus on the leukocytes. The present studies deal with the role of the direct antiphagocytic effect of influenza virus in the enhanced susceptibility to bacterial infection that is associated with influenza. In addition, earlier investigations of PMN interaction with virus [11-14] and of the direct antiphagocytic action of influenza virus on PMN [8-10] have been extended to other types of leukocytes and to cells from other species.