Molecular and cytotoxic effects of camptothecin, a topoisomerase I inhibitor, on trypanosomes and Leishmania.

Parasites pose a threat to the health and lives of many millions of human beings. Among the pathogenic protozoa, Trypanosoma brucei, Trypanosoma cruzi, and Leishmania donovani are hemoflagellates that cause particularly serious diseases (sleeping sickness, Chagas disease, and leishmaniasis, respectively). The drugs currently available to treat these infections are limited by marginal efficacy, severe toxicity, and spreading drug resistance. Camptothecin is an established antitumor drug and a well-characterized inhibitor of eukaryotic DNA topoisomerase I. When trypanosomes or leishmania are treated with camptothecin and then lysed with SDS, both nuclear and mitochondrial DNA are cleaved and covalently linked to protein. This is consistent with the existence of drug-sensitive topoisomerase I activity in both compartments. Camptothecin also inhibits the incorporation of [3H]thymidine in these parasites. These molecular effects are cytotoxic to cells in vitro, with EC50 values for T. brucei, T. cruzi, and L. donovani, of 1.5, 1.6, and 3.2 microM, respectively. For these parasites, camptothecin is an important lead for much-needed new chemotherapy, as well as a valuable tool for studying topoisomerase I activity.

Iontophoresis for modulation of cardiac drug delivery in dogs.

Cardiac arrhythmias are a frequent cause of death and morbidity. Conventional antiarrhythmia therapy involving oral or intravenous medication is often ineffective and complicated by drug-associated side effects. Previous studies from our laboratory have demonstrated the advantages of cardiac drug-polymer implants for enhanced efficacy for cardiac arrhythmia therapy compared with conventional administration. However, these studies were based on systems that deliver drugs at a fixed release rate. Modulation of the drug delivery rate has the advantage of regulating the amount of the drug delivered depending upon the disease state of the patient. We hypothesized that iontophoresis could be used to modulate cardiac drug delivery. In this study, we report our investigations of a cardiac drug implant in dogs that is capable of iontophoretic modulation of the administration of the antiarrhythmic agent sotalol. We used a heterogeneous cation-exchange membrane (HCM) as an electrically sensitive and highly efficient rate-limiting barrier on the cardiac-contacting surface of the implant. Thus, electric current is passed only through the HCM and not the myocardium. The iontophoretic cardiac implant demonstrated in vitro drug release rates that were responsive to current modulation. In vivo results in dogs have confirmed that iontophoresis resulted in regional coronary enhancement of sotalol levels with current-responsive increases in drug concentrations. We also observed acute current-dependent changes in ventricular effective refractory periods reflecting sotalol-induced refractoriness due to regional drug administration. In 30-day dog experiments, iontophoretic cardiac implants demonstrated robust sustained function and reproducible modulation of drug delivery kinetics.

Electrohydrodynamic Atomization for Improved Macromolecular Drug Delivery

With advances in drug research, the use of biological therapeutics is becoming a reality. Unfortunately, methods for processing and delivering these fragile macromolecules often limit their therapeutic potential. For this dissertation, we explore the aerosolization of macromolecules by way of electrohydrodynamic atomization (EHDA) and how this method can be used to process and deliver therapeutics. EHDA employs a high voltage to break a column of liquid into drops. It was unknown if or how the residual charge left of the resulting droplets would affect lung cells. An in vitro experiment was conducted to spray aerosolized DNA, by way of EHDA, onto human derived lungs cells to test for immunogenic and toxic effects. The lung cells displayed no immunogenic or toxic response to the DNA or high voltage. Previous researchers have used EHDA to aerosolize proteins with mixed results. This work sets forth a simplified thermodynamic theory and provides recommendations to pharmaceutical companies on how to design more stable protein formulations for aerosol processing or delivery. Finally, a new method of producing liposomes was created. It constructs the liposome one layer at a time. The inside of the liposome is sprayed by EHDA, with the lipid and drug in solution together. As the sprayed monolayer passes through a pool containing a solution of lipid in water, the second part of the bilayer attaches to the inner layer creating a complete bilayer liposome.

Profound activity of the anti-cancer drug bortezomib against Echinococcus multilocularis metacestodes identifies the proteasome as a novel drug target for cestodes.

A library of 426 FDA-approved drugs was screened for in vitro activity against E. multilocularis metacestodes employing the phosphoglucose isomerase (PGI) assay. Initial screening at 20 µM revealed that 7 drugs induced considerable metacestode damage, and further dose-response studies revealed that bortezomib (BTZ), a proteasome inhibitor developed for the chemotherapy of myeloma, displayed high anti-metacestodal activity with an EC50 of 0.6 µM. BTZ treatment of E. multilocularis metacestodes led to an accumulation of ubiquinated proteins and unequivocally parasite death. In-gel zymography assays using E. multilocularis extracts demonstrated BTZ-mediated inhibition of protease activity in a band of approximately 23 kDa, the same size at which the proteasome subunit beta 5 of E. multilocularis could be detected by Western blot. Balb/c mice experimentally infected with E. multilocularis metacestodes were used to assess BTZ treatment, starting at 6 weeks post-infection by intraperitoneal injection of BTZ. This treatment led to reduced parasite weight, but to a degree that was not statistically significant, and it induced adverse effects such as diarrhea and neurological symptoms. In conclusion, the proteasome was identified as a drug target in E. multilocularis metacestodes that can be efficiently inhibited by BTZ in vitro. However, translation of these findings into in vivo efficacy requires further adjustments of treatment regimens using BTZ, or possibly other proteasome inhibitors.

Epileptic networks are strongly connected with and without the effects of interictal discharges

OBJECTIVE Epilepsy is increasingly considered as the dysfunction of a pathologic neuronal network (epileptic network) rather than a single focal source. We aimed to assess the interactions between the regions that comprise the epileptic network and to investigate their dependence on the occurrence of interictal epileptiform discharges (IEDs). METHODS We analyzed resting state simultaneous electroencephalography-functional magnetic resonance imaging (EEG-fMRI) recordings in 10 patients with drug-resistant focal epilepsy with multifocal IED-related blood oxygen level-dependent (BOLD) responses and a maximum t-value in the IED field. We computed functional connectivity (FC) maps of the epileptic network using two types of seed: (1) a 10-mm diameter sphere centered in the global maximum of IED-related BOLD map, and (2) the independent component with highest correlation to the IED-related BOLD map, named epileptic component. For both approaches, we compared FC maps before and after regressing out the effect of IEDs in terms of maximum and mean t-values and percentage of map overlap. RESULTS Maximum and mean FC maps t-values were significantly lower after regressing out IEDs at the group level (p < 0.01). Overlap extent was 85% ± 12% and 87% ± 12% when the seed was the 10-mm diameter sphere and the epileptic component, respectively. SIGNIFICANCE Regions involved in a specific epileptic network show coherent BOLD fluctuations independent of scalp EEG IEDs. FC topography and strength is largely preserved by removing the IED effect. This could represent a signature of a sustained pathologic network with contribution from epileptic activity invisible to the scalp EEG.

The pragmatics of computer-mediated communication between South African and Mexican drug traffickers

South Africa and Mexico are ripe with drug trafficking. The gangs and syndicates running the drug businesses in these two countries collaborate occasionally. Communication between these international drug business partners takes place on social media. Their main language of communication is English, mixed with some limited use of Spanish and Afrikaans. The key purpose of the interactions between the South African and Mexican parties is the organisation of their business activities. This study aims at examining how the drug traffickers position each other and themselves regarding their common business interest and how their relationship evolves throughout their interactions. Moreover, it is of interest to look at how these people make use of different social media and their affordances. For this a qualitative analysis of the interaction between two drug traffickers (one South African and one Mexican) on Facebook, Threema and PlayStation 4 was performed. Computer-mediated communication between these two main informants was studied at various stages of their relationship. Results show that at first the interaction between the South African and Mexican drug traffickers consists of interpersonal negotiations of power. The high risk of the drug business and gang/syndicate membership paired with intercultural frictions causes the two interlocutors to be extremely cautious and at the same time to mark their position. As their relationship develops and they gain trust in each other a shift to interpersonal negotiations of solidarity takes place. In these discursive practices diverse linguistic strategies are employed for creating relational effects and for positioning the other and the self. The discursive activities of the interactants are also identity practices. Thus, the two drug traffickers construct identities through these social practices, positioning and their interpersonal relationship.

The biological effects of ionizing radiation ; an overview /

Mode of access: Internet.

Symposium on Biological Effects and Measurement of Radio Frequency/Microwaves : proceedings of a conference held in Rockville, Maryland, February 16-18, 1977/

Includes bibliographical references.

Teratologic effects of long-term exposure to diesel exhaust emissions (rabbits) /

"Contract no. 68-03-2652."

Analysis of some laser light show effects for classification purposes /

Mode of access: Internet.

Airborne ultrasound : measurement and possible adverse effects /

Mode of access: Internet.

A review of biological effects and potential risks associated with ultraviolet radiation as used in dentistry /

Mode of access: Internet.

Effects of foods and drugs on the development and function of the nervous system : methods for predicting toxicity /

Symposium organized by the Office of Health Affairs, Food and Drug Administration.

A simulator study of the combined effects of alcohol and marihuana on driving behavior. Phase II. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Effects of GeneXpert MTB/RIF Testing and GxAlert eHealth Platforms on MDR-TB Diagnosis and Linkage to Care in Sofala Province, Mozambique

Thesis (Master's)--University of Washington, 2016-06