Complex epistatic interactions between ELF3, PRR9, and PRR7 regulate the circadian clock and plant physiology

Circadian clocks are endogenous timekeeping mechanisms that coordinate internal physiological responses with the external environment. EARLY FLOWERING3 (ELF3), PSEUDO RESPONSE REGULATOR (PRR9), and PRR7 are essential components of the plant circadian clock and facilitate entrainment of the clock to internal and external stimuli. Previous studies have highlighted a critical role for ELF3 in repressing the expression of PRR9 and PRR7. However, the functional significance of activity in regulating circadian clock dynamics and plant development is unknown. To explore this regulatory dynamic further, we first employed mathematical modeling to simulate the effect of the prr9/prr7 mutation on the elf3 circadian phenotype. These simulations suggested that simultaneous mutations in prr9/prr7 could rescue the elf3 circadian arrhythmia. Following these simulations, we generated all Arabidopsis elf3/prr9/prr7 mutant combinations and investigated their circadian and developmental phenotypes. Although these assays could not replicate the results from the mathematical modeling, our results have revealed a complex epistatic relationship between ELF3 and PRR9/7 in regulating different aspects of plant development. ELF3 was essential for hypocotyl development under ambient and warm temperatures, while PRR9 was critical for root thermomorphogenesis. Finally, mutations in prr9 and prr7 rescued the photoperiod-insensitive flowering phenotype of the elf3 mutant. Together, our results highlight the importance of investigating the genetic relationship among plant circadian genes.

AraLeTA: An Arabidopsis leaf expression atlas across diurnal and developmental scales

Mature plant leaves are a composite of distinct cell types, including epidermal, mesophyll and vascular cells. Notably the proportion of these cells, and the relative transcript concentrations within different cell types, may change over time. While gene expression data at a single-cell level can provide cell-type-specific expression values, it is often too expensive to obtain this data for high-resolution time series. Although bulk RNA-seq can be performed in a high-resolution time series, RNA-seq using whole leaves measures average gene expression values across all cell types in each sample. In this study, we combined single-cell RNA-seq data with time-series data from whole leaves to assemble an atlas of cell-type-specific changes in gene expression over time for Arabidopsis (Arabidopsis thaliana). We inferred how the relative transcript concentrations of different cell types vary across diurnal and developmental time scales. Importantly, this analysis revealed three sub-groups of mesophyll cells with distinct temporal profiles of expression. Finally, we developed tissue-specific gene networks that form a community resource: An Arabidopsis Leaf Time-Dependent Atlas (AraLeTa). This allows users to extract gene networks that are confirmed by transcription factor binding data and specific to certain cell types at certain times of day and at certain developmental stages. AraLeTa is available at: https://regulatorynet.shinyapps.io/araleta/.

Women in Irish urology: An examination of female representation amongst attendees of the Irish Society of Urology annual meeting (2008-2020)

BACKGROUND

There is underrepresentation of women at surgical conferences. We examine the representation of women in Irish urology by looking at gender balance within the Irish Society of Urology (ISU) conference.

AIMS

ISU programmes over thirteen years from 2008 to 2020 were assessed and female representation in session chairs, guest speakers, poster and oral presentations identified. Gender distributions of authors for each year was examined. To investigate changes in female representation temporally, the period of this study (2008-2020) was subdivided and compared: 2008-2013 and 2014-2020.

RESULTS

76 sessions were presided over by 138 chairs, of which 6 (4.3%) were female. Eight conferences had zero female chairs. 62 guest lectures were given, 6 (9.6%) by women. Of total 340 poster and 434 oral presentations, women delivered 24.9% (0-47.5%) of posters and 31.6% (10.3-59.4%) of oral presentations. We found no significant difference in the percentage of female poster presentations between the time periods 2008-2013 (m = 18.2, sd = 13.7) and 2014-2020 (m = 34.3, sd = 17.8), t(11) = -1.4, p > 0.05. However, we found a significant difference in the percentage of female oral presentations between the periods 2008-2013 (m = 18.7, sd = 14.2) and 2014-2020 (m = 40.6, sd = 14.5), t(11) = -2.8, p < 0.05.

CONCLUSIONS

Our study is the second to examine female representation in Irish urology. Session chairs and guest speakers were grossly overrepresented by males as were oral and poster presentations. Despite lacking female influence overall, in more recent years there was an increased representation of women. Societies should strive to increase female representation, as this perpetuates a positive feedback loop, encouraging future female trainees to pursue urological surgery.

Does instillation of lidocaine gel following flexible cystoscopy decrease the severity of post procedure symptoms? A randomised controlled trial assessing the efficacy of lidocaine gel post flexible cystoscopy

Objective

To assess whether instillation of lidocaine gel both before and after flexible cystoscopy is more effective at reducing post procedural symptoms than instillation of lidocaine gel pre flexible cystoscopy alone. We hypothesise that inadequate urethral dwell time and dilution of lidocaine gel by the irrigation fluid during flexible cystoscopy limits its anaesthetic efficacy. Only one other study has attempted to reduce bothersome urinary symptoms through an intervention after flexible cystoscopy.

Methods

This was a randomised controlled trial in which patients were randomised 1:1 to receive lidocaine gel pre and post flexible cystoscopy (treatment) or lidocaine gel pre flexible cystoscopy only (control). Patient-reported outcome measures were used to assess symptoms and quality of life prior to cystoscopy, on day 2 and day 7 post cystoscopy.

Result

Fifty patients were divided equally between the treatment and control groups. There were no significant differences in baseline characteristics between the groups (p = 1.000). An overall symptoms variable was measured, though no significant difference was found in the distribution of responses between the groups at baseline, 2 or 7 days after the flexible cystoscopy (p = 0.423, 0.651,0.735). In the treatment group, 1 patient (4.0%) presented to a doctor for review following flexible cystoscopy, and 4 patients (16.0%) presented in the control group (p = 0.349).

Conclusion

Initial study results suggest that post-operative lidocaine does not significantly limit the exacerbation of urinary symptoms following flexible cystoscopy; however, our results are not powered to detect a small difference. We do not recommend a change in practice based on our results.

Esophagitis in Sprague-Dawley rats is mediated by free radicals

Free radical-mediated esophagitis was studied during duodenogastroesophageal reflux (mixed reflux) or acid reflux in rats. The influence of reflux on esophageal glutathione levels was also examined. Mixed reflux caused more gross mucosal injury than acid reflux. Gross mucosal injury occurred in the mid-esophagus. Total glutathione (GSH) in the esophageal mucosa of control rats was highest in the distal esophagus. The time course of esophageal GSH in rats treated by mixed reflux showed a significant decrease 4 hr after initiation of reflux, followed by a significant increase from the 12th hour on. Mucosal GSH was increased in both reflux groups after 24 hr but significantly more so in the mixed than in the acid reflux group. The free radical scavenger superoxide dismutase (SOD) prevented esophagitis and was associated with decreased GSH levels. GSH depletion by buthionine sulfoximine (BSO) prevented esophagitis and stimulated SOD production in the esophageal mucosa. It is concluded that gastroesophageal reflux is associated with oxidative stress in the esophageal mucosa. The lower GSH levels in the mid-esophagus may predispose to damage in this area. Duodenogastroesophageal reflux causes more damage than pure acid reflux. Oxidative stress leads to GSH depletion of the esophageal mucosa in the first few hours following damage but then stimulates GSH production. GSH depletion by BSO does not worsen esophagitis since it increases the esophageal SOD concentration.

Free radical scavengers prevent reflux esophagitis in rats

Free radical damage in reflux esophagitis of rats induced by 24-hr duodenojejunal ligation was studied. Oxygen free radicals were selectively blocked. Groups were: sham operation, reflux, reflux + superoxide dismutase (SOD), catalase, dimethylthiourea, allopurinol, and inactivated SOD or inactivated catalase alone or in the combination SOD + catalase or SOD + catalase + dimethylthiourea + allopurinol. Macroscopic esophagitis was inhibited only by SOD, alone or in combination with other agents. Esophageal mucosal lipid peroxidation was 10-fold increased in the reflux group compared to the sham group (P < 0.05). This response was damped by SOD > catalase (P < 0.05) but not by the inactivated enzymes, dimethylthiourea or allopurinol. SOD + catalase showed no significant improvement on SOD alone. Total inhibition of lipid peroxidation was achieved by combining all scavengers. Total glutathione (GSH) in the esophageal mucosa was stimulated by reflux. This response was inhibited by scavengers equivalent to their efficacy in preventing lipid peroxidation. It is concluded that reflux esophagitis is associated with free radical release with O2- being the main source. Free radicals appear to stimulate GSH production in this prolonged oxidative stress.

In vitro free radical production in rat esophageal mucosa induced by nicotine

Oxidative stress induced by nicotine was investigated in the esophageal mucosa of rats. The homogenized mucosa was incubated for 30 min with 50, 100, 200, 400, and 800 ng/mg protein/ml nicotine or with 200 ng/mg protein/ml nicotine for 15, 30, 45, and 60 min. Esophageal mucosa was also incubated for 30 min with 200 ng/mg protein/ml nicotine with or without the scavengers superoxide dismutase (SOD), catalase, SOD+catalase, inactivated SOD, inactivated catalase, or albumin. Incubation with 0.9% NaCl served as control. There was a strong correlation between chemiluminescence and the nicotine dose (r = 0.75) or the nicotine incubation time (r = 0.77). Thirty-minute incubation of the esophageal mucosa with 200 ng/mg protein/ml nicotine increased chemiluminescence 5.5-fold and lipid peroxidation 3.3-fold. This response was dampened by SOD or catalase and abolished by SOD+catalase. Inactivated enzymes or albumin had no scavenging effect. These results demonstrate that nicotine causes oxidative stress to the esophageal mucosa.

Prolonged ambulatory antroduodenal manometry in humans

OBJECTIVES

To perform prolonged ambulatory recordings of antroduodenal motor activity in humans.

METHODS

Antroduodenal manometric recordings were performed in 20 normal subjects (12 male, eight female, ages 19-41 years), using a 5-channel solid state catheter assembly (three antral, two duodenal transducers) positioned under fluoroscopy. A glass electrode simultaneously recorded pH in the antrum.

RESULTS

Continuous, simultaneous recordings of antral and duodenal motor activity were obtained for 22.5 +/- 0.3 h. During fasting, 131 complete migrating motor complexes (MMCs) were recorded (6.6 +/- 0.9/subject). The average interval from onset of recording to completion of the first MMC cycle was 498 +/- 19.24 minutes. Significant diurnal variations were observed in MMC frequency (awake vs asleep: 0.25/subject/h vs 0.64/subject/h; p < 0.05), period (shorter during sleep), phase I duration (longer during sleep), and phase II duration (shorter during sleep). Among females, MMCs were more frequent and shorter. After meal administration, duodenal recording sites demonstrated a typical "fed" response; antral distension and/or retrograde catheter movement, on meal ingestion, however, precluded reliable antral "fed" recordings.

CONCLUSIONS

Prolonged ambulatory antroduodenal manometry provides detailed and reliable information on fasting antral and duodenal motor activity, antral distension, and/or retrograde catheter migration on meal ingestion; there are limits, however, to the usefulness of this methodology for the evaluation of the fed motor response in the antrum.

Gastroesophageal reflux disease is associated with enteric hormone abnormalities

Basal and postprandial levels of the foregut hormones gastrin, cholecystokinin (CCK), motilin, and pancreatic polypeptide, and the distal gut hormones neurotensin and peptide YY were measured in 20 patients with gastroesophageal reflux disease (GERD). GERD was defined by abnormal esophageal exposure to pH less than 4. Ten GERD patients had decreased lower esophageal sphincter (LES) pressure (mean: 4.5 mm Hg, range: 0.8 to 6.8 mm Hg), and 10 patients had normal LES pressures (mean: 14.1 mm Hg, range: 9.7 to 22.4 mm Hg). Eight age-matched healthy subjects were also studied. Basal levels of peptide YY were moderately decreased in GERD patients compared with controls irrespective of LES pressure. In patients with abnormal LES pressure, basal levels of motilin and the postprandial response of CCK were significantly decreased compared with controls; and basal levels of neurotensin and the postprandial response of gastrin were significantly increased compared with controls. Pancreatic polypeptide levels were similar in all groups. These gut hormone changes, which are more marked in patients with poor LES pressure, may reflect primary or secondary abnormalities in GERD.

Acute ischaemia of the lower limb: an unusual presenting feature of acute lymphoblastic leukaemia

Malignant disease is often complicated by coagulation disorders presenting as abnormal clotting or bleeding, acute leukaemia being more often associated with the latter. Acute lymphoblastic leukaemia presenting with peripheral arterial thromboembolism, previously unreported in the literature, is presented. Aetiology, clinical features, and management of coagulation disturbances associated with malignancy are also reviewed.