Population biology of malaria within the mosquito: density-dependent processes and potential implications for transmission-blocking interventions

<p>Abstract</p> <p>Background</p> <p>The combined effects of multiple density-dependent, regulatory processes may have an important impact on the growth and stability of a population. In a malaria model system, it has been shown that the progression of <it>Plasmodium berghei </it>through <it>Anopheles stephensi </it>and the survival of the mosquito both depend non-linearly on parasite density. These processes regulating the development of the malaria parasite within the mosquito may influence the success of transmission-blocking interventions (TBIs) currently under development.</p> <p>Methods</p> <p>An individual-based stochastic mathematical model is used to investigate the combined impact of these multiple regulatory processes and examine how TBIs, which target different parasite life-stages within the mosquito, may influence overall parasite transmission.</p> <p>Results</p> <p>The best parasite molecular targets will vary between different epidemiological settings. Interventions that reduce ookinete density beneath a threshold level are likely to have auxiliary benefits, as transmission would be further reduced by density-dependent processes that restrict sporogonic development at low parasite densities. TBIs which reduce parasite density but fail to clear the parasite could cause a modest increase in transmission by increasing the number of infectious bites made by a mosquito during its lifetime whilst failing to sufficiently reduce its infectivity. Interventions with a higher variance in efficacy will therefore tend to cause a greater reduction in overall transmission than a TBI with a more uniform effectiveness. Care should be taken when interpreting these results as parasite intensity values in natural parasite-vector combinations of human malaria are likely to be significantly lower than those in this model system.</p> <p>Conclusions</p> <p>A greater understanding of the development of the malaria parasite within the mosquito is required to fully evaluate the impact of TBIs. If parasite-induced vector mortality influenced the population dynamics of <it>Plasmodium </it>species infecting humans in malaria endemic regions, it would be important to quantify the variability and duration of TBI efficacy to ensure that community benefits of control measures are not overestimated.</p

Target 2035-update on the quest for a probe for every protein

Twenty years after the publication of the first draft of the human genome, our knowledge of the human proteome is still fragmented. The challenge of translating the wealth of new knowledge from genomics into new medicines is that proteins, and not genes, are the primary executers of biological function. Therefore, much of how biology works in health and disease must be understood through the lens of protein function. Accordingly, a subset of human proteins has been at the heart of research interests of scientists over the centuries, and we have accumulated varying degrees of knowledge about approximately 65% of the human proteome. Nevertheless, a large proportion of proteins in the human proteome (∼35%) remains uncharacterized, and less than 5% of the human proteome has been successfully targeted for drug discovery. This highlights the profound disconnect between our abilities to obtain genetic information and subsequent development of effective medicines. Target 2035 is an international federation of biomedical scientists from the public and private sectors, which aims to address this gap by developing and applying new technologies to create by year 2035 chemogenomic libraries, chemical probes, and/or biological probes for the entire human proteome

In Support of a Patient-Driven Initiative and Petition to Lower the High Price of Cancer Drugs

Comment in Lowering the High Cost of Cancer Drugs--III. [Mayo Clin Proc. 2016] Lowering the High Cost of Cancer Drugs--I. [Mayo Clin Proc. 2016] Lowering the High Cost of Cancer Drugs--IV. [Mayo Clin Proc. 2016] In Reply--Lowering the High Cost of Cancer Drugs. [Mayo Clin Proc. 2016] US oncologists call for government regulation to curb drug price rises. [BMJ. 2015

ICAR: endoscopic skull‐base surgery

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Downregulation of Akt1 Inhibits Anchorage-Independent Cell Growth and Induces Apoptosis in Cancer Cells

The serine/threonine kinases, Akt1/PKBα, Akt2/PKBβ, and Akt3/PKBγ, play a critical role in preventing cancer cells from undergoing apoptosis. However, the function of individual Akt isoforms in the tumorigenicity of cancer cells is still not well defined. In the current study, we used an Akt1 antisense oligonucleotide (AS) to specifically downregulate Akt1 protein in both cancer and normal cells. Our data indicate that Akt1 AS treatment inhibits the ability of MiaPaCa-2, H460, HCT-15, and HT1080 cells to grow in soft agar. The treatment also induces apoptosis in these cancer cells as demonstrated by FACS analysis and a caspase activity assay. Conversely, Akt1 AS treatment has little effect on the cell growth and survival of normal human cells including normal human fibroblast (NHF), fibroblast from muscle (FBM), and mammary gland epithelial 184B5 cells. In addition, Akt1 AS specifically sensitizes cancer cells to typical chemotherapeutic agents. Thus, Akt1 is indispensable for maintaining the tumorigenicity of cancer cells. Inhibition of Akt1 may provide a powerful sensitization agent for chemotherapy specifically in cancer cells

Risk of therapy-related secondary leukemia in Hodgkin lymphoma: the Stanford University experience over three generations of clinical trials

To assess therapy-related acute myeloid leukemia/myelodysplastic syndrome (t-AML/MDS) risk in patients treated for Hodgkin lymphoma (HL) on successive generations of Stanford clinical trials. Patients with HL treated at Stanford with at least 5 years of follow-up after completing therapy were identified from our database. Records were reviewed for outcome and development of t-AML/MDS. Seven hundred fifty-four patients treated from 1974 to 2003 were identified. Therapy varied across studies. Radiotherapy evolved from extended fields (S and C studies) to involved fields (G studies). Primary chemotherapy was mechlorethamine, vincristine, procarbazine, and prednisone (MOPP) or procarbazine, mechlorethamine, and vinblastine (PAVe) in S studies; MOPP, PAVe, vinblastine, bleomycin, and methotrexate (VBM), or doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) in C studies; and VbM (reduced dose of bleomycin compared with VBM) or mechlorethamine, doxorubicin, vinblastine, vincristine, bleomycin, etoposide, and prednisone (Stanford V) in G studies. Cumulative exposure to alkylating agent (AA) was notably lower in the G studies compared with the S and C studies, with a 75% to 83% lower dose of nitrogen mustard in addition to omission of procarbazine and melphalan. Twenty-four (3.2%) of 754 patients developed t-AML/MDS, 15 after primary chemotherapy and nine after salvage chemotherapy for relapsed HL. The incidence of t-AML/MDS was significantly lower in the G studies (0.3%) compared with the S (5.7%) or C (5.2%) studies (P < .001). Additionally, in the G studies, no t-AML/MDS was noted after primary therapy, and the only patient who developed t-AML/MDS did so after second-line therapy. Our data demonstrate the relationship between the cumulative AA dose and t-AML/MDS. Limiting the dose of AA and decreased need for secondary treatments have significantly reduced the incidence of t-AML/MDS, which was extremely rare in the G studies (Stanford V era)