GnRH-Agonist Ovulation Trigger in Patients Undergoing Controlled Ovarian Hyperstimulation for IVF with Stop GnRH-Agonist Combined with Multidose GnRH-Antagonist Protocol.

OBJECTIVE: This study aimed to characterize those patients undergoing the stop gonadotropin-releasing hormone (GnRH)-agonist combined with multidose GnRH-antagonist protocol, with suboptimal response to GnRH-agonist trigger in in vitro fertilization (IVF) cycles. DESIGN: This is a cohort study. SETTING: The study was conducted in a university hospital. PATIENTS: All consecutive women admitted to our IVF unit from February 2020 through November 2020 who reached the ovum pick-up stage were reviewed. INTERVENTIONS: Triggering final oocyte maturation by GnRH-ag alone (GnRH-ag trigger group), or combined with hCG (dual trigger group), in patients undergoing the stop GnRH-agonist combined with multidose GnRH-antagonist protocol was performed. MAIN OUTCOME MEASURE: The main outcome measure was LH level 12 h after the trigger. RESULTS: Five out of the 32 patients (15.6%) demonstrated suboptimal response as reflected by LH levels <15 IU/L 12 h after GnRH-agonist trigger. Moreover, while no differences were observed in oocyte recovery rate, maturity, or embryo quality between the different study groups (GnRH-ag trigger and dual trigger groups), those achieving a suboptimal response to the GnRH-agonist trigger (post-trigger LH <15 mIU/mL) demonstrated significantly higher number of follicles and peak estradiol levels at the day of trigger, compared to those with optimal response (post-trigger LH >15 mIU/mL). CONCLUSIONS: The stop GnRH-agonist combined with GnRH-antagonist protocol enables the substitution of hCG with GnRH-ag for final oocyte maturation. However, caution should be taken in high responders, where the dual trigger with small doses of hCG (1,000-1,500 IU) should be considered, aiming to avoid suboptimal response (post-trigger LH levels <15 IU/L).

Myiasis in Neglected Cutaneous Squamous Cell Carcinoma of the Head and Neck: Review of Management and Current Protocol Recommendations.

OBJECTIVE: To propose a first-aid management protocol for myiasis in neglected cutaneous squamous cell carcinoma (SCC) in the ED based on a recent literature review. DATA SOURCES: PubMed. STUDY SELECTION: Inclusion criteria were all series and case reports of primary/secondary cutaneous SCC with myiasis of the head and neck, including orbital SCC cases, published after 2005. DATA EXTRACTION: A total of 14 articles including 15 patients were included. DATA SYNTHESIS: Demographics, socioeconomic situation, site of the lesion, larvae species with bacterial suprainfection, and first-aid treatment options were discussed. Two representative cases are described. CONCLUSIONS: Large, ulcerated, necrotic, myiasis-burdened SCC lesions in the head and neck area present a challenge for treatment, and to date, no consensus regarding first-aid management exists. The authors' proposed four-pillar first-aid management scheme may be a valid option to rapidly improve wound condition through disinfection, pain relief, and malodor and discharge eradication as a bridge to surgery.

Outcomes of the Bethesda system for reporting thyroid cytopathology: Real-life experience.

OBJECTIVE: The 2017 revised Bethesda System for Reporting Thyroid Cytopathology (BSRTC) included new malignancy rates for each category as well as new management recommendations. Here, we evaluate the malignancy rate and test performance for BSRTC categories in a middle-sized institution outside the United States (US). DESIGN: Retrospective single centre case series with chart review. PATIENTS: All patients who underwent thyroid surgery with a preoperative BSRTC between the years 2010 and 2018 at our institution. MEASUREMENTS: In order to assess the malignancy rate for each BSRTC, all medical records were reviewed to collect demographics, nodule's size, BSRTC and final pathology. RESULTS: Three hundred and sixty-four patients were included, with an overall malignancy rate of 34.3%. The malignancy rate for BSRTC categories I-VI was as follows: 13.3%, 5.1%, 25.0%, 24.4%, 91.3% and 95.2%, respectively. The most sensitive test was when BSRTC III-VI were evaluated (91%). Overall best performance (sensitivity, specificity, PPV, NPV and accuracy) was obtained when BSRTC V-VI were grouped together with a substantial decrease when adding BSRTC III-IV (90%, 97%, 94%, 95%, 95% vs, respectively, 91%, 73%, 62%, 95%, 79%, respectively). CONCLUSIONS: Despite differences from the reported 2017 BSRTC malignancy rates, we demonstrated that the revised 2017 BSRTC management recommendations for thyroid nodules are also valid in smaller non-US centre, supporting its use globally.

Detecting allosteric sites of HIV-1 reverse transcriptase by X-ray crystallographic fragment screening.

HIV-1 reverse transcriptase (RT) undergoes a series of conformational changes during viral replication and is a central target for antiretroviral therapy. The intrinsic flexibility of RT can provide novel allosteric sites for inhibition. Crystals of RT that diffract X-rays to better than 2 Å resolution facilitated the probing of RT for new druggable sites using fragment screening by X-ray crystallography. A total of 775 fragments were grouped into 143 cocktails, which were soaked into crystals of RT in complex with the non-nucleoside drug rilpivirine (TMC278). Seven new sites were discovered, including the Incoming Nucleotide Binding, Knuckles, NNRTI Adjacent, and 399 sites, located in the polymerase region of RT, and the 428, RNase H Primer Grip Adjacent, and 507 sites, located in the RNase H region. Three of these sites (Knuckles, NNRTI Adjacent, and Incoming Nucleotide Binding) are inhibitory and provide opportunities for discovery of new anti-AIDS drugs.

Structural basis of HIV-1 resistance to AZT by excision.

Human immunodeficiency virus (HIV-1) develops resistance to 3'-azido-2',3'-deoxythymidine (AZT, zidovudine) by acquiring mutations in reverse transcriptase that enhance the ATP-mediated excision of AZT monophosphate from the 3' end of the primer. The excision reaction occurs at the dNTP-binding site, uses ATP as a pyrophosphate donor, unblocks the primer terminus and allows reverse transcriptase to continue viral DNA synthesis. The excision product is AZT adenosine dinucleoside tetraphosphate (AZTppppA). We determined five crystal structures: wild-type reverse transcriptase-double-stranded DNA (RT-dsDNA)-AZTppppA; AZT-resistant (AZTr; M41L D67N K70R T215Y K219Q) RT-dsDNA-AZTppppA; AZTr RT-dsDNA terminated with AZT at dNTP- and primer-binding sites; and AZTr apo reverse transcriptase. The AMP part of AZTppppA bound differently to wild-type and AZTr reverse transcriptases, whereas the AZT triphosphate part bound the two enzymes similarly. Thus, the resistance mutations create a high-affinity ATP-binding site. The structure of the site provides an opportunity to design inhibitors of AZT-monophosphate excision.

Molecular dynamics study of non-nucleoside reverse transcriptase inhibitor 4-[[4-[[4-[(E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2-pyrimidinyl]amino]benzonitrile (TMC278/rilpivirine) aggregates: correlation between amphiphilic properties of the drug and oral bioavailability.

The non-nucleoside reverse transcriptase inhibitor (NNRTI) TMC278/rilpivirine is an anti-AIDS therapeutic agent with high oral bioavailability despite its high hydrophobicity. Previous studies established a correlation between ability of the drug molecule to form stable, homogeneous populations of spherical nanoparticles (approximately 100-120 nm in diameter) at low pH in surfactant-independent fashion and good oral bioavailability. Here, we hypothesize that the drug is able to assume surfactant-like properties under physiologically relevant conditions, thus facilitating formation of nanostructures in the absence of other surfactants. The results of all-atom molecular dynamics simulations indeed show that protonated drug molecules behave as surfactants at the water/aggregate interface while neutral drug molecules assist aggregate packing via conformational variability. Our simulation results suggest that amphiphilic behavior at low pH and intrinsic flexibility influence drug aggregation and are believed to play critical roles in the favorable oral bioavailability of hydrophobic drugs.

High-resolution structures of HIV-1 reverse transcriptase/TMC278 complexes: strategic flexibility explains potency against resistance mutations.

TMC278 is a diarylpyrimidine (DAPY) nonnucleoside reverse transcriptase inhibitor (NNRTI) that is highly effective in treating wild-type and drug-resistant HIV-1 infections in clinical trials at relatively low doses ( approximately 25-75 mg/day). We have determined the structure of wild-type HIV-1 RT complexed with TMC278 at 1.8 A resolution, using an RT crystal form engineered by systematic RT mutagenesis. This high-resolution structure reveals that the cyanovinyl group of TMC278 is positioned in a hydrophobic tunnel connecting the NNRTI-binding pocket to the nucleic acid-binding cleft. The crystal structures of TMC278 in complexes with the double mutant K103N/Y181C (2.1 A) and L100I/K103N HIV-1 RTs (2.9 A) demonstrated that TMC278 adapts to bind mutant RTs. In the K103N/Y181C RT/TMC278 structure, loss of the aromatic ring interaction caused by the Y181C mutation is counterbalanced by interactions between the cyanovinyl group of TMC278 and the aromatic side chain of Y183, which is facilitated by an approximately 1.5 A shift of the conserved Y(183)MDD motif. In the L100I/K103N RT/TMC278 structure, the binding mode of TMC278 is significantly altered so that the drug conforms to changes in the binding pocket primarily caused by the L100I mutation. The flexible binding pocket acts as a molecular "shrink wrap" that makes a shape complementary to the optimized TMC278 in wild-type and drug-resistant forms of HIV-1 RT. The crystal structures provide a better understanding of how the flexibility of an inhibitor can compensate for drug-resistance mutations.

In search of a novel anti-HIV drug: multidisciplinary coordination in the discovery of 4-[[4-[[4-[(1E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2- pyrimidinyl]amino]benzonitrile (R278474, rilpivirine).

Ideally, an anti-HIV drug should (1) be highly active against wild-type and mutant HIV without allowing breakthrough; (2) have high oral bioavailability and long elimination half-life, allowing once-daily oral treatment at low doses; (3) have minimal adverse effects; and (4) be easy to synthesize and formulate. R278474, a new diarylpyrimidine (DAPY) non-nucleoside reverse transcriptase inhibitor (NNRTI), appears to meet these criteria and to be suitable for high compliance oral treatment of HIV-1 infection. The discovery of R278474 was the result of a coordinated multidisciplinary effort involving medicinal chemists, virologists, crystallographers, molecular modelers, toxicologists, analytical chemists, pharmacists, and many others.

Concentration and pH dependent aggregation of hydrophobic drug molecules and relevance to oral bioavailability.

We have examined selected physicochemical properties of compounds from the diaryltriazine/diarylpyrimidine (DATA/DAPY) classes of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and explored possible correlations with their bioavailability. In simple aqueous solutions designed to mimic the gastrointestinal (GI) environment of a fasting individual, all NNRTIs demonstrated formation of aggregates as detected by dynamic light scattering and electron microscopy. Under various conditions mimicking physiological transitions in the GI environment, aggregate size distributions were shown to depend on compound concentration and pH. NNRTIs with good absorption were capable of forming aggregates with hydrodynamic radii of /=250 nm at concentrations above 0.01 mM, probably representing precipitate. We propose a model in which the uptake rate into systemic circulation depends on having hydrophobic drug aggregates of appropriate size available for absorption at different locations within the GI tract.