Residues 386 -423 of the rat brain serotonin transporter (SERT) are predicted to form a hydrophilic loop connecting transmembrane spans 7 and 8 (extracellular loop 4 or EL4). EL4 has been hypothesized to play a role in conformational changes associated with substrate translocation. To more fully investigate EL4 structure and function, we performed cysteine-scanning mutagenesis and methanethiosulfonate (MTS) accessibility studies on these 38 residues. Four EL4 mutants (M386C, R390C, G402C, and L405C) showed very low transport activities, low cell surface expression, and strong inhibition by MTS reagents, indicating high structural and functional importance. Twelve mutants were sensitive to very low MTS concentrations, indicating positions highly exposed to the aqueous environment. Eleven mutants were MTS-insensitive, indicating positions that were either buried in EL4 structure or functionally unimportant. The patterns of sensitivity to mutation and MTS reagents were used to produce a structural model of EL4. Positions 386 -399 and 409 -421 are proposed to form ␣-helices, connected by nine consecutive MTS-sensitive positions, within which four positions, 402-405, may form a turn or hinge. The presence of serotonin changed the MTS accessibility of cysteines at nine positions, while cocaine, a non-transportable blocker, did not affect accessibility. Serotonin-induced accessibility changes required both Na ؉ and Cl ؊ , indicating that they were associated with active substrate translocation. With the exception of a single mutant, F407C, neither mutation to cysteine nor treatment with MTS reagents affected SERT affinities for serotonin or the cocaine analog ␤-CIT. These studies support the role of EL4 in conformational changes occurring during translocation and show that it does not play a direct role in serotonin binding.During chemical neurotransmission, neurotransmitters are released into the synaptic cleft, then taken back up into the presynaptic cell. This re-uptake is catalyzed by a large, highly homologous family of membrane transport proteins known as the neurotransmitter/sodium symporter (NSS) 1 family (1). The NSS transporters couple the uptake of specific neurotransmitters and/or amino acids to the transmembrane gradients of Na ϩ , Cl Ϫ , and in some cases, K ϩ or H ϩ (for a recent review, see Ref.2). Within this family, the closely related biogenic amine subfamily is responsible for the re-uptake of serotonin, dopamine, and norepinephrine. These transporters are the targets of antidepressants, cocaine, and amphetamines in the brain (3, 4).The high sequence homology among the NSS transporters suggests a common architecture, predicted to consist of 12 membrane spanning ␣-helices. This general topology has been confirmed experimentally for the serotonin transporter (SERT) (5-8). However, the three-dimensional packing of these membrane spans is still largely unknown, as is the molecular mechanism by which these transporters bind and translocate their substrates.Much recent work has focused on the TM7-EL4-TM8 ...

Cutaneous leishmaniasis is a parasitic infection that causes significant maternal morbidity, and even fetal mortality, during pregnancy, yet there are limited therapeutic options. Here, we report a case of leishmaniasis in a pregnant immigrant with exuberant mucocutaneous lesions with favorable response to liposomal amphotericin B.

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INTRODUCTION: Point-of-care ultrasonography (POCUS) is increasingly used in medicine and is widely integrated into training. While obstetric (OB) ultrasound (US) is prevalent, its formal use and curriculum is often overlooked in POCUS training. METHODS: We performed a prospective comparative study of medical students who underwent formal obstetrics POCUS training and simulation. Students participated in a pre- and post-knowledge assessment of basic (presentation, placentation, fluid) and advanced (biometry and basic anatomy) knowledge. Scores were compared via Wilcoxon signed-ranks test. In addition to formal didactics, students participated in hands-on simulation training. The simulation provided one-on-one biometry training with a high-fidelity CIRS model 065-20 fetal model. Participants were evaluated on their ability to perform a complete fetal biometry. RESULTS: There were 58 participants in formal POCUS simulation training. Prior to training, only 29.7% were comfortable with a basic OB US and 8.1% were comfortable with performing biometry. Afterwards, 83.8% and 78.4% were comfortable performing basic and biometry US. Students had significantly higher basic OB US knowledge comparing before (Mdn=50.0) to after training (Mdn=83.3) (Z=5.27, P<.01). Similarly, there was a significant increase in advanced OB US knowledge comparing before (Mdn=56.3) to after (Mdn=100.0) (Z=4.99, P<.01). All participants were able to complete biometry measurements on the CIRS model. 91.9% of participants recommended this training to others. CONCLUSION: Obstetric ultrasound provides invaluable opportunity for learners to gain POCUS skills. Formal training and simulation significantly improves learning knowledge, confidence, and practical OB POCUS skills that can be used during clinical care.

Pregnant patients who received nondiagnostic ferritin labs at less than 20 weeks of gestation from 2019 to 2021 were retrospectively identified. Patients were excluded if ferritin testing was conducted for diagnostic purposes or if the patient had a history of anemia. Labs at the time of registration, 28 weeks of gestation, and at delivery were analyzed. Anemia was defined as Hgb less than 11 g/dL. This study was approved by the University of Washington IRB, and patient consent was waived.RESULTS: Forty-four patients underwent routine ferritin screening at registration, with ferritin levels ranging from 10 to 136 ng/mL (average 52.5 ng/mL). Average Hgb/Hct at registration were 12.6 g/dL and 37.3%, respectively. At 28 weeks of gestation, Hgb/Hct were obtained on 42 patients, of whom 9 patients were diagnosed with anemia. Patients diagnosed with anemia had a screening ferritin level of 33.6 ng/mL, and nonanemic patients had a ferritin level of 57.4 ng/mL (P 5.1). When a cutoff of 50 ng/mL was studied to compare patients with "low" versus "normal" ferritin, ferritin less than or equal to 50 ng/ mL had significantly lower Hgb levels at 28 weeks compared to those with ferritin greater than 50 ng/mL (P 5.013). On labor and delivery (L&D), Hgb/Hct was obtained on 44 patients, and 14 were diagnosed with anemia. Anemic patients on L&D had significantly lower screening ferritin compared to nonanemic, 31.9 and 62.2 ng/mL, respectively (P 5.016).CONCLUSION: Ferritin screening in early pregnancy may help predict lower Hgb in later gestation. Using a higher ferritin cutoff of 50 ng/mL in early pregnancy for identifying patients at risk for anemia in the third trimester may be warranted. Larger prospective studies are needed to evaluate further the utility of ferritin screening.