A case of severe and prolonged γ-hydroxybutyrate (GHB) withdrawal syndrome successfully managed with a slow benzodiazepine and baclofen taper.

INTRODUCTION: γ-hydroxybutyrate (GHB) is a GABA-B agonist that rapidly produces effects that are likened to both alcohol and MDMA/ecstasy. GHB use can lead to neuroadaptation with a characteristic withdrawal syndrome. There is currently a paucity of data on the progression of GHB withdrawal, however, due to the drug's short half-life it is generally considered to be typically 5-7 days, although some cases can be severe and complicated by life threatening delirium. Here, we present a case of severe GHB withdrawal, which recurred on multiple occasions over 56 days, despite initial clinical stabilisation on each occasion and toxicological evidence of abstinence from GHB between episodes. CASE PRESENTATION: A male patient in his 30s presented with agitated delirium on a background of severe GHB use disorder with a 15-year history of daily high dose GHB use. Following 3 hospital admissions over 8 weeks, all requiring intravenous sedation and tracheal intubation, the patient's withdrawal delirium was successfully treated with a slow benzodiazepine and baclofen wean over a period of 6 months. Relapse to GHB use between hospitalisations was excluded toxicologically via blood analysis performed at an institute of forensic pathology. DISCUSSION AND CONCLUSIONS: This case highlights that GHB withdrawal can be more prolonged than previously reported in the literature and in some cases may require slow and prolonged tapering of treatment to prevent re-emergence of delirium. Similar to previous case reports, benzodiazepines and GABA-B receptor agonists appear to be appropriate drug classes to manage GHB withdrawal.

Dynamic Adaptation in Extant Porins Facilitates Antibiotic Tolerance in Energetic Escherichia coli.

Bacteria can tolerate antibiotics despite lacking the genetic components for resistance. The prevailing notion is that tolerance results from depleted cellular energy or cell dormancy. In contrast to this view, many cells in the tolerant population of Escherichia coli can exhibit motility - a phenomenon that requires cellular energy, specifically, the proton-motive force (PMF). As these motile-tolerant cells are challenging to isolate from the heterogeneous tolerant population, their survival mechanism is unknown. Here, we discovered that motile bacteria segregate themselves from the tolerant population under micro-confinement, owing to their unique ability to penetrate micron-sized channels. Single-cell measurements on the motile-tolerant population showed that the cells retained a high PMF, but they did not survive through active efflux alone. By utilizing growth assays, single-cell fluorescence studies, and chemotaxis assays, we showed that the cells survived by dynamically inhibiting the function of existing porins in the outer membrane. A drug transport model for porin-mediated intake and efflux pump-mediated expulsion suggested that energetic tolerant cells withstand antibiotics by constricting their porins. The novel porin adaptation we have uncovered is independent of gene expression changes and may involve electrostatic modifications within individual porins to prevent extracellular ligand entry.

Reassessing the Standard Chemotaxis Framework for Understanding Biased Migration in Helicobacter pylori.

Helicobacter pylori infections are a major cause of peptic ulcers and gastric cancers. The development of robust inflammation in response to these flagellated, motile bacteria is correlated with poor prognosis. Chemotaxis plays a crucial role in H. pylori colonization, enabling the bacteria to swim toward favorable chemical environments. Unlike the model species of bacterial chemotaxis, Escherichia coli, H. pylori cells possess polar flagella. They run forward by rotating their flagella counterclockwise, whereas backward runs are achieved by rotating their flagella clockwise. We delve into the implications of certain features of the canonical model of chemotaxis on our understanding of biased migration in polarly flagellated bacteria such as H. pylori. In particular, we predict how the translational displacement of H. pylori cells during a backward run could give rise to chemotaxis errors within the canonical framework. Also, H. pylori lack key chemotaxis enzymes found in E. coli, without which sensitive detection of ligands with a wide dynamic range seems unlikely. Despite these problems, H. pylori exhibit robust ability to migrate toward urea-rich sources. We emphasize various unresolved questions regarding the biophysical mechanisms of chemotaxis in H. pylori, shedding light on potential directions for future research. Understanding the intricacies of biased migration in H. pylori could offer valuable insights into how pathogens breach various protective barriers in the human host. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering , Volume 15 is June 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Use of dupilumab for atopic dermatitis in young transplant patients-A case series of 3 patients.

Patients who undergo solid organ transplantation are at an increased risk of developing atopic dermatitis, potentially due to long-term use of calcineurin inhibitors which results in a shift towards the Th2 immune response. The effectiveness and safety of dupilumab for atopic dermatitis in posttransplant patients is not established. Previous reports of dupilumab use in posttransplant patients have been in adult patients. In this series, we report three young posttransplant patients treated successfully with dupilumab.

Periorbital reconstructive techniques following Mohs micrographic surgery or excisions: a systematic review.

There are many articles in the literature on periorbital reconstruction after Mohs micrographic surgery (MMS) or surgical excision, however, the literature lacks a comprehensive systematic review of these reports. We performed a systematic review of published data on periorbital defect reconstruction to identify trends in the literature. A comprehensive search of eight databases was performed. To be included in the study, articles had to be published in English between 2005 and 2020 and contain repair data for MMS or excision defects in the periorbital region. Studies with less than four patients, literature or systematic reviews, and abstract-only publications were excluded. Data extracted from eligible articles included the authors' medical specialties, study design, subject number and demographics, defect characteristics, procedure type, reconstructive methods, complications, outcome measures, and method of outcome assessment. 53 studies met the inclusion criteria. The first and last authors' specialties were ophthalmology (47%), plastic and reconstructive surgery (23%), dermatology (13%), otolaryngology (4%), or were multi-specialty collaborations (13%). Only 5 of the studies were prospective. Defects were located on the lower eyelid (55%), medial canthus (31%), upper eyelid (8%), lateral canthus (4%), or a combination of these sites (2%). Reconstructive methods were reported for 3678 cases and included linear repair (18%), advancement flap (8%), rotation flap (5%), transposition flap (3%), island pedicle flap (1%), unspecified local skin flap (21%), skin graft (23%), secondary intention (4%), tarsoconjunctival flap (3%), and combined reconstruction techniques (13%). Thirty-three of 53 articles specified the periorbital subunit for each reconstructive technique that was employed. Among these 33 articles which allowed for correlation between defect location and reconstructive technique, the most utilized repair method for lower eyelid defects was local skin flap. Defects on the upper eyelid or medial canthus were most frequently repaired with a skin graft. Forty articles commented on cosmetic outcomes, however, only 3 of these articles utilized a defined grading system, objective measurements, or independent reviewers to assess the cosmetic outcomes. The methods of reconstruction in this review were diverse, however, local skin flaps and grafts were the most utilized techniques. In future reports, increased reporting of reconstructive technique by defect location as well as increased use of standardized assessments of aesthetic outcomes can help strengthen this body of literature.

Heterogeneous Distribution of Proton Motive Force in Nonheritable Antibiotic Resistance.

Bacterial infections that are difficult to eradicate are often treated by sequentially exposing the bacteria to different antibiotics. Although effective, this approach can give rise to epigenetic or other phenomena that may help some cells adapt to and tolerate the antibiotics. Characteristics of such adapted cells are dormancy and low energy levels, which promote survival without lending long-term genetic resistance against antibiotics. In this work, we quantified motility in cells of Escherichia coli that adapted and survived sequential exposure to lethal doses of antibiotics. In populations that adapted to transcriptional inhibition by rifampicin, we observed that ~1 of 3 cells continued swimming for several hours in the presence of lethal concentrations of ampicillin. As motility is powered by proton motive force (PMF), our results suggested that many adapted cells retained a high PMF. Single-cell growth assays revealed that the high-PMF cells resuscitated and divided upon the removal of ampicillin, just as the low-PMF cells did, a behavior reminiscent of persister cells. Our results are consistent with the notion that cells in a clonal population may employ multiple different mechanisms to adapt to antibiotic stresses. Variable PMF is likely a feature of a bet-hedging strategy: a fraction of the adapted cell population lies dormant while the other fraction retains high PMF to be able to swim out of the deleterious environment. IMPORTANCE Bacterial cells with low PMF may survive antibiotic stress due to dormancy, which favors nonheritable resistance without genetic mutations or acquisitions. On the other hand, cells with high PMF are less tolerant, as PMF helps in the uptake of certain antibiotics. Here, we quantified flagellar motility as an indirect measure of the PMF in cells of Escherichia coli that had adapted to ampicillin. Despite the disadvantage of maintaining a high PMF in the presence of antibiotics, we observed high PMF in ~30% of the cells, as evidenced by their ability to swim rapidly for several hours. These and other results were consistent with the idea that antibiotic tolerance can arise via different mechanisms in a clonal population.

Bacterial Proprioception: Can a Bacterium Sense Its Movement?

The evolution of the bacterial flagellum gave rise to motility and repurposing of a signaling network, now termed the chemotaxis network, enabled biasing of cell movements. This made it possible for the bacterium to seek out favorable chemical environments. To enable chemotaxis, the chemotaxis network sensitively detects extracellular chemical stimuli and appropriately modulates flagellar functions. Additionally, the flagellar motor itself is capable of detecting mechanical stimuli and adapts its structure and function in response, likely triggering a transition from planktonic to surface-associated lifestyles. Recent work has shown a link between the flagellar motor's response to mechanical stimuli and the chemotactic output. Here, we elaborate on this link and discuss how it likely helps the cell sense and adapt to changes in its swimming speeds in different environments. We discuss the mechanism whereby the motor precisely tunes its chemotaxis output under different mechanical loads, analogous to proprioception in higher order organisms. We speculate on the roles bacterial proprioception might play in a variety of phenomena including the transition to surface-associated lifestyles such as swarming and biofilms.

Indole modulates cooperative protein-protein interactions in the flagellar motor.

Indole is a major component of the bacterial exometabolome, and the mechanisms for its wide-ranging effects on bacterial physiology are biomedically significant, although they remain poorly understood. Here, we determined how indole modulates the functions of a widely conserved motility apparatus, the bacterial flagellum. Our experiments in Escherichia coli revealed that indole influences the rotation rates and reversals in the flagellum's direction of rotation via multiple mechanisms. At concentrations higher than 1 mM, indole decreased the membrane potential to dissipate the power available for the rotation of the motor that operates the flagellum. Below 1 mM, indole did not dissipate the membrane potential. Instead, experiments and modeling indicated that indole weakens cooperative protein interactions within the flagellar complexes to inhibit motility. The metabolite also induced reversals in the rotational direction of the motor to promote a weak chemotactic response, even when the chemotaxis response regulator, CheY, was lacking. Experiments further revealed that indole does not require the transporter Mtr to cross the membrane and influence motor functions. Based on these findings, we propose that indole modulates intra- and inter-protein interactions in the cell to influence several physiological functions.

Mechanosensitive recruitment of stator units promotes binding of the response regulator CheY-P to the flagellar motor.

Reversible switching of the bacterial flagellar motor between clockwise (CW) and counterclockwise (CCW) rotation is necessary for chemotaxis, which enables cells to swim towards favorable chemical habitats. Increase in the viscous resistance to the rotation of the motor (mechanical load) inhibits switching. However, cells must maintain homeostasis in switching to navigate within environments of different viscosities. The mechanism by which the cell maintains optimal chemotactic function under varying loads is not understood. Here, we show that the flagellar motor allosterically controls the binding affinity of the chemotaxis response regulator, CheY-P, to the flagellar switch complex by modulating the mechanical forces acting on the rotor. Mechanosensitive CheY-P binding compensates for the load-induced loss of switching by precisely adapting the switch response to a mechanical stimulus. The interplay between mechanical forces and CheY-P binding tunes the chemotactic function to match the load. This adaptive response of the chemotaxis output to mechanical stimuli resembles the proprioceptive feedback in the neuromuscular systems of insects and vertebrates.

Long-term Physical and Psychological Outcomes of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis.

IMPORTANCE: Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is known to cause multiple end-organ complications in its acute phase, but less is known about the long-term association with patients' mental health and quality of life. OBJECTIVE: To examine the chronic physical and psychological sequelae affecting patients with SJS/TEN. DESIGN, SETTING, AND PARTICIPANTS: A survey study conducted at 11 academic health centers in the US evaluated 121 adults diagnosed with SJS/TEN by inpatient consultive dermatologists between January 1, 2009, and September 30, 2019. INTERVENTIONS: Patients completed a survey that included the following validated questionnaires: Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Primary Care Post-Traumatic Stress Disorder Screen (PC-PTSD), and the 12-item Short Form Health Survey (SF-12). The survey also included questions created by the study team regarding fear, patient education, and long-term sequelae relevant to SJS/TEN. MAIN OUTCOMES AND MEASURES: Primary outcome measures were the percentage of patients reporting long-term physical sequelae; the percentage of patients with positive results on PHQ-9, GAD-7, and PC-PTSD screening; and the numeric score on the SF-12 (score of 50 defined as average physical and mental well-being). RESULTS: A total of 121 individuals (73 women [60.3%]; mean [SD] age, 52.5 [17.1] years) completed the survey (response rate, 29.2%). The most common long-term physical sequelae reported were cutaneous problems (102 of 121 [84.3%]), ocular problems (72 of 121 [59.5%]), and oral mucosal problems (61 of 120 [50.8%]). A total of 53.3% (64 of 120) of the respondents had results indicating depression on the PHQ-9, 43.3% (52 of 120) showed signs of anxiety on the GAD-7, and 19.5% had results indicating PTSD on the PC-PTSD. The mean (SD) SF-12 Physical Component Summary score was 42.4 (22.8), and the mean Mental Component Summary score was 46.1 (20.9). A total of 28.2% (33 of 117) of the respondents were unable to work, 68.1% (81 of 119) were fearful of taking new medications, and 30.0% (36 of 120) avoided taking prescribed medications for a diagnosed medical condition. CONCLUSIONS AND RELEVANCE: This survey study found that long-term physical sequelae, depression, and anxiety appear to be common in patients with SJS/TEN, with implications for health and well-being. Improved awareness of these complications may assist health professionals in offering medical care, counseling, and support to patients with SJS/TEN.