...all known genetic predispositions will be available and, depending on the data sharing policy, accessible to a wide range of researchers and, possibly, the public at large--this, at a time when we ...are still seeking to understand the social, clinical, and personal implications of genetic information. More research and policy analysis on the issues associated with data release is clearly needed, including an analysis of the actual harms and benefits resulting from publicly accessible data; the implications for family members and relevant communities; the appropriate balance between public access and individual privacy interests; and considerations regarding compensation for research-related injury resulting from participation in personal genome research.
Highlights • Placebo controls may be acceptable even when an efficacious vaccine exists, in the following four possible situations: • When developing a locally affordable vaccine. • When evaluating ...the local safety and efficacy of an existing vaccine. • When testing a new vaccine when an existing vaccine is not considered appropriate locally. • When determining the local burden of disease.
One of the greatest barriers to the treatment of cancer with chemotherapeutic drugs is acquisition of drug resistance. This includes multidrug resistance mediated by P-glycoprotein (Pgp) to multiple ...lipophilic natural compounds such as taxanes, doxorubicin (Adriamycin), and vinblastine. The considerable efforts made thus far to reverse this and other types of drug resistance have had very limited success. We report here that a variety of orthotopic human breast cancer xenografts selected for high levels of Pgp and multidrug resistance respond in a significant and durable manner to different continuous low-dose (e.g., one-tenth the maximum tolerated dose of chemotherapy) chemotherapy regimens, when used in combination with an antivascular endothelial cell growth factor (anti-VEGF) receptor-2 (flk-1)-neutralizing antibody (DC101). The Pgp substrates paclitaxel (Taxol), Adriamycin, and vinblastine were all effective using this type of combination treatment, although the chemotherapy protocols showed little or no effect as monotherapies. Similar results were also obtained using cisplatinum (a non-Pgp substrate drug) against cisplatinum-resistant tumors. Evidence of significant tumor cell death by the combination treatment was detected within 3 weeks of initiation of therapy by histopathological analysis, in the absence of shrinkage of tumor mass. There were, however, marked differences in the cumulative toxicity of long-term regimens of Adriamycin and cisplatinum, where toxicity was observed, when compared with the tubulin inhibitors, vinblastine and Taxol, where it was not. We conclude that vascular-targeting protocols involving frequent administration of very low doses of certain chemotherapeutic drugs can provide a stable and safe way to circumvent multidrug resistance in established orthotopically growing tumors, as long as these are used in combination with a second antiangiogenic drug, in this case, anti-VEGFR-2 blocking antibodies.
We report on the various responses in Australia during 2020 to minimize negative impacts of the COVID-19 pandemic on the welfare of animals. Most organizations and individuals with animals under ...their care had emergency preparedness plans in place for various scenarios; however, the restrictions on human movement to contain the spread of COVID-19, coupled with the economic impact and the health effects of COVID-19 on the skilled workforce, constituted a new threat to animal welfare for which there was no blueprint. The spontaneous formation of a national, multisectoral response group on animal welfare, consisting of more than 34 organizations with animals under their care, facilitated information flow during the crisis, which helped to mitigate some of the shocks to different organizations and to ensure continuity of care for animals during the pandemic. We conclude that animal welfare is a shared responsibility, and accordingly, a multisectoral approach to animal welfare during a crisis is required. Our experience demonstrates that to safeguard animal welfare during crises, nations should consider the following: a national risk assessment, clear communication channels, contingency plans for animal welfare, a crisis response group, and support systems for animal care providers. Our findings and recommendations from the Australian context may inform other countries to ensure that animal welfare is not compromised during the course of unpredictable events.
A major obstacle compromising the successful application of many of the new targeted anticancer drugs, including angiogenesis inhibitors, is the empiricism associated with determining an effective ...biological/therapeutic dose because many of these drugs express optimum therapeutic activity below the maximum tolerated dose, if such a dose can be defined. Hence, surrogate markers are needed to help determine optimal dosing. Here we describe such a molecular marker, increased plasma levels of vascular endothelial growth factor (VEGF), in normal or tumor-bearing mice that received injections of an anti-VEGF receptor (VEGFR)-2 monoclonal antibody, such as DC101. Rapid increases of mouse VEGF (e.g., within 24 hours) up to 1 order of magnitude were observed after single injections of DC101 in non-tumor-bearing severe combined immunodeficient or nude mice; similar increases in human plasma VEGF were detected in human tumor-bearing mice. RAFL-1, another anti-VEGFR-2 antibody, also caused a significant increase in plasma VEGF. In contrast, increases in mouse VEGF levels were not seen when small molecule VEGFR-2 inhibitors were tested in normal mice. Most importantly, the increases in plasma VEGF were induced in a dose-dependent manner, with the maximum values peaking when doses previously determined to be optimally therapeutic were used. Plasma VEGF should be considered as a possible surrogate pharmacodynamic marker for determining the optimal biological dose of antibody drugs that block VEGFR-2 (KDR) activity in a clinical setting.
A number of recent preclinical studies have sparked interest in the concept of exploiting conventional chemotherapeutic drugs as antiangiogenics. Such antiangiogenic activity is achieved or optimized ...by metronomic-dosing protocols in which the drug is given at comparatively low doses using a frequent schedule of administration (e.g., once to three times per week) with no breaks, particularly when combined with an endothelial cell-specific antiangiogenic drug. The use of p.o. chemotherapeutic drugs is particularly suitable for this type of treatment strategy. We tested one such drug, cyclophosphamide (CTX), in a protocol wherein the drug was administered to mice at low doses, of approximately 10-40 mg/kg on a daily basis through the drinking water. CTX is typically given p.o. to patients, but it has almost always been injected when treating preclinical mouse tumor models. We found p.o. CTX to be a safe and convenient treatment with significant antitumor efficacy. Growth delays were observed for human orthotopic breast or ectopic colon cancer xenografts in nude or SCID mice. Established PC3 human prostate tumor xenografts could be induced to almost fully regress, remaining virtually nonpalpable for > or =2 months of continuous therapy, after which tumors began to grow progressively. These re-emergent tumors were not found to be drug resistant when tested in new hosts, using the same treatment protocol. Regression of spontaneously arising, late-stage pancreatic islet cell carcinomas in Rip Tag transgenic mice was also observed. The effects of continuous p.o. CTX treatment were enhanced significantly in an orthotopic, metastatic breast cancer xenograft model when used in combination with an antivascular endothelial growth factor receptor-2 blocking antibody. Maximum tolerated dose levels established for other mouse strains proved highly toxic to SCID mice, whereas daily p.o. low-dose regimens of CTX were well tolerated. Taken together, the results demonstrate the feasibility of delivering CTX in a p.o. metronomic chemotherapy regimen, which proved safe, reasonably efficacious, and potentially applicable to chronic treatment. Such a regimen may be particularly well suited for integration with antiangiogenic drugs.
This study presents a structure-function analysis of the mammalian left ventricle and examines the performance of the cardiac capillary network, mitochondria, and myofibrils at rest and during ...simulated heavy exercise. Left ventricular external mechanical work rate was calculated from cardiac output and systemic mean arterial blood pressure in resting sheep (Ovis aries; n = 4) and goats (Capra hircus; n = 4) under mild sedation, followed by perfusion-fixation of the left ventricle and quantification of the cardiac capillary-tissue geometry and cardiomyocyte ultrastructure. The investigation was then extended to heavy exercise by increasing cardiac work according to published hemodynamics of sheep and goats performing sustained treadmill exercise. Left ventricular work rate averaged 0.017 W/cm
of tissue at rest and was estimated to increase to ∼0.060 W/cm
during heavy exercise. According to an oxygen transport model we applied to the left ventricular tissue, we predicted that oxygen consumption increases from 195 nmol O
·s
·cm
of tissue at rest to ∼600 nmol O
·s
·cm
during heavy exercise, which is within 90% of the oxygen demand rate and consistent with work remaining predominantly aerobic. Mitochondria represent 21-22% of cardiomyocyte volume and consume oxygen at a rate of 1,150 nmol O
·s
·cm
of mitochondria at rest and ∼3,600 nmol O
·s
·cm
during heavy exercise, which is within 80% of maximum in vitro rates and consistent with mitochondria operating near their functional limits. Myofibrils represent 65-66% of cardiomyocyte volume, and according to a Laplacian model of the left ventricular chamber, generate peak fiber tensions in the range of 50 to 70 kPa at rest and during heavy exercise, which is less than maximum tension of isolated cardiac tissue (120-140 kPa) and is explained by an apparent reserve capacity for tension development built into the left ventricle.
Since first proposed 2, there has been some attention to the evolution of CSREs in the literature 3, 4, with much of the focus on how to achieve an appropriate balance between the ...advisory/consulting role of the emerging CSREs and the review, monitoring, and oversight responsibilities of their counterpart institutional review boards (IRBs) 5. ...the importance of integration, of looking for broad applications of narrowly intended solutions, of bringing diverse perspectives to bear on complex ethical challenges, and of rigorous impact evaluation are by no means limited to global health; as such, we hope these lessons may also prove useful for CSREs focused on a wide range of scientific endeavors.
Diarrheal disease caused by rotavirus claims approximately 500 000 lives each year, mostly in low-income countries. Many of these deaths are preventable through the use of available rotavirus ...vaccines. Yet, in spite of a WHO recommendation that these vaccines be adopted into all national immunization programs, only a few countries have done so.
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