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Current Protocols Feb 2024In vitro electrophysiological safety studies have become an integral part of the drug development process because, in many instances, compound-induced QT prolongation...
In vitro electrophysiological safety studies have become an integral part of the drug development process because, in many instances, compound-induced QT prolongation has been associated with a direct block of human ether-a-go-go-related gene (hERG) potassium channels or their native current, the rapidly activating delayed rectifier potassium current (I ). Therefore, according to the ICH S7B guideline, the in vitro hERG channel patch-clamp assay is commonly used as an early screen to predict the ability of a compound to prolong the QT interval prior to first-in-human testing. The protocols described in this article are designed to assess the effects of acute or long-term exposure to new chemical entities on the amplitude of I in HEK293 cells stably transfected with the hERG channel (whole-cell configuration of the patch-clamp technique). Examples of results obtained with moxifloxacin, terfenadine, arsenic, pentamidine, erythromycin, and sotalol are provided for illustrative purposes. © 2024 Wiley Periodicals LLC. Basic Protocol: Measurement of the acute effects of test items in the hERG channel test Alternate Protocol: Measurement of the long-term effects of test items in the hERG channel test.
Topics: Humans; Ether-A-Go-Go Potassium Channels; Patch-Clamp Techniques; HEK293 Cells; Sotalol; Erythromycin
PubMed: 38334240
DOI: 10.1002/cpz1.959 -
Transplantation Proceedings May 2024Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that, in immunocompromised patients, can progress to respiratory failure and death. Since...
Pneumocystis jirovecii Pneumonia in a Liver Transplant Recipient With an Adverse Reaction to Trimethoprim/Sulfamethoxazole Treated With a Sulfonamide Desensitization Protocol: Case Report.
BACKGROUND
Pneumocystis jirovecii pneumonia (PJP) is an opportunistic fungal infection that, in immunocompromised patients, can progress to respiratory failure and death. Since trimethoprim/sulfamethoxazole (TMP/SMX) chemoprophylaxis has become a standard management, the prognosis has improved. However, there are patients with a history of TMP/SMX intolerance who cannot receive chemoprophylaxis.
BACKGROUND
We report on a 53-year-old male liver recipient treated with a standard triple immunosuppressive regimen in whom TMP/SMX was waived because of a history of allergy manifested as a generalized rash with edema more than 30 years ago. At transplantation, the immunologic risk was assessed as low, and liver graft function was normal. In the third month after engraftment, he developed dyspnea at rest required constant passive oxygen therapy. Ceftriaxone, azithromycin, and clindamycin were implemented. Mycophenolate acid was stopped, and tacrolimus was reduced. High-resolution computed tomography revealed interstitial pneumonia. Pneumocystis jirovecii pneumoniae was diagnosed from bronchoalveolar lavage. Instead of TMP/SMX, pentamidine and caspofungin were also used for PJP, with no improvement. After 3 weeks, the patient deteriorated. Because of his life-threatening condition, TMP/SMX was introduced in the sulfonamide desensitization protocol, including hydrocortisone and clemastinum. Within 4 days, the patient stabilized with no signs of TMP/SMX intolerance. Pneumonia subsided within a month, and TMP/SMX was prescribed lifelong.
CONCLUSIONS
Prophylaxis for PJP with TMP/SMX still remains an important issue in transplant recipients. Adverse reaction to TMP/SMX in the past is not always a contraindication to reintroducing prophylaxis. The decision of prophylaxis avoidance should be analyzed carefully; in uncertain cases, a sulfonamide desensitization protocol should be considered.
Topics: Humans; Male; Middle Aged; Pneumonia, Pneumocystis; Trimethoprim, Sulfamethoxazole Drug Combination; Liver Transplantation; Pneumocystis carinii; Sulfonamides; Desensitization, Immunologic; Immunocompromised Host; Immunosuppressive Agents
PubMed: 38760300
DOI: 10.1016/j.transproceed.2024.03.022 -
PLoS Neglected Tropical Diseases May 2024In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is...
In Brazil, Leishmania amazonensis is the etiological agent of cutaneous and diffuse cutaneous leishmaniasis. The state of Maranhão in the Northeast of Brazil is prevalent for these clinical forms of the disease and also has high rates of HIV infection. Here, we characterized the drug susceptibility of a L. amazonensis clinical isolate from a 46-year-old man with diffuse cutaneous leishmaniasis coinfected with HIV from this endemic area. This patient underwent several therapeutic regimens with meglumine antimoniate, liposomal amphotericin B, and pentamidine, without success. In vitro susceptibility assays against promastigotes and intracellular amastigotes demonstrated that this isolate had low susceptibility to amphotericin B, when compared with the reference strain of this species that is considered susceptible to antileishmanial drugs. Additionally, we investigated whether the low in vitro susceptibility would affect the in vivo response to amphotericin B treatment. The drug was effective in reducing the lesion size and parasite burden in mice infected with the reference strain, whereas those infected with the clinical isolate and a resistant line (generated experimentally by stepwise selection) were refractory to amphotericin B treatment. To evaluate whether the isolate was intrinsically resistant to amphotericin B in animals, infected mice were treated with other drugs that had not been used in the treatment of the patient (miltefosine, paromomycin, and a combination of both). Our findings demonstrated that all drug schemes were able to reduce lesion size and parasite burden in animals infected with the clinical isolate, confirming the amphotericin B-resistance phenotype. These findings indicate that the treatment failure observed in the patient may be associated with amphotericin B resistance, and demonstrate the potential emergence of amphotericin B-resistant L. amazonensis isolates in an area of Brazil endemic for cutaneous leishmaniasis.
Topics: Amphotericin B; Animals; Brazil; Middle Aged; Antiprotozoal Agents; Humans; Male; Mice; Drug Resistance; Leishmania; Leishmania mexicana; Leishmaniasis, Cutaneous; HIV Infections; Parasitic Sensitivity Tests; Mice, Inbred BALB C; Leishmaniasis, Diffuse Cutaneous
PubMed: 38768213
DOI: 10.1371/journal.pntd.0012175 -
Journal of Medicinal Chemistry Jun 2024Several G-quadruplex nucleic acid (G4s) ligands have been developed seeking target selectivity in the past decade. Naphthalene diimide (NDI)-based compounds are...
Several G-quadruplex nucleic acid (G4s) ligands have been developed seeking target selectivity in the past decade. Naphthalene diimide (NDI)-based compounds are particularly promising due to their biological activity and red-fluorescence emission. Previously, we demonstrated the existence of G4s in the promoter region of parasite genomes, assessing the effectiveness of NDI-derivatives against them. Here, we explored the biological activity of a small library of G4-DNA ligands, exploiting the NDI pharmacophore, against both and parasites. Biophysical and biological assays were conducted. Among the various families analyzed, core-extended NDIs exhibited the most promising results concerning the selectivity and antiparasitic effects. NDI emerged as the most potent, with an IC of 0.011 nM against and remarkable selectivity vs MRC-5 cells (3454-fold). Fascinating, is 480-fold more potent than the standard drug pentamidine (IC = 5.3 nM). Cellular uptake and parasite localization were verified by exploiting core-extended NDI red-fluorescent emission.
PubMed: 38924701
DOI: 10.1021/acs.jmedchem.4c00135