Hoxb2 and Hoxb4 Act Together to Specify Ventral Body Wall Formation

AbstractThree different alleles of the Hoxb4 locus were generated by gene targeting in mice. Two alleles contain insertions of a selectable marker in the first exon in either orientation, and, in the third, the selectable marker was removed, resulting in premature termination of the protein. Presence and orientation of the selectable marker correlated with the severity of the phenotype, indicating that the selectable marker induces cis effects on neighboring genes that influence the phenotype. Homozygous mutants of all alleles had cervical skeletal defects similar to those previously reported for Hoxb4 mutant mice. In the most severe allele, Hoxb4PolII, homozygous mutants died eitherin utero at approximately E15.5 or immediately after birth, with a severe defect in ventral body wall formation. Analysis of embryos showed thinning of the primary ventral body wall in mutants relative to control animals at E11.5, before secondary body wall formation. Prior to this defect, both Alx3 and Alx4 were specifically down regulated in the most ventral part of the primary body wall in Hoxb4PolII mutants. Hoxb4loxp mutants in which theneo gene has been removed did not have body wall or sternum defects. In contrast, both the Hoxb4PolII and the previously described Hoxb2PolII alleles that have body wall defects have been shown to disrupt the expression of bothHoxb2 and Hoxb4 in cell types that contribute to body wall formation. Our results are consistent with a model in which defects in ventral body wall formation require the simultaneous loss of at least Hoxb2 and Hoxb4, and may involve Alx3 and Alx4

Phosducin-like protein 1 is essential for G-protein assembly and signaling in retinal rod photoreceptors

G protein β subunits perform essential neuronal functions as part of G protein βγ and Gβ(5)-RGS (Regulators of G protein Signaling) complexes. Both Gβγ and Gβ(5)-RGS are obligate dimers that are thought to require the assistance of the cytosolic chaperonin CCT and a co-chaperone, phosducin-like protein 1 (PhLP1) for dimer formation. To test this hypothesis in vivo, we deleted the Phlp1 gene in mouse (Mus musculus) retinal rod photoreceptor cells and measured the effects on G protein biogenesis and visual signal transduction. In the PhLP1-depleted rods, Gβγ dimer formation was decreased 50-fold, resulting in a more than 10-fold decrease in light sensitivity. Moreover, a 20-fold reduction in Gβ(5) and RGS9-1 expression was also observed, causing a 15-fold delay in the shutoff of light responses. These findings conclusively demonstrate in vivo that PhLP1 is required for the folding and assembly of both Gβγ and Gβ(5)-RGS9

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

Dimethyl fumarate in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial

Dimethyl fumarate (DMF) inhibits inflammasome-mediated inflammation and has been proposed as a treatment for patients hospitalised with COVID-19. This randomised, controlled, open-label platform trial (Randomised Evaluation of COVID-19 Therapy [RECOVERY]), is assessing multiple treatments in patients hospitalised for COVID-19 (NCT04381936, ISRCTN50189673). In this assessment of DMF performed at 27 UK hospitals, adults were randomly allocated (1:1) to either usual standard of care alone or usual standard of care plus DMF. The primary outcome was clinical status on day 5 measured on a seven-point ordinal scale. Secondary outcomes were time to sustained improvement in clinical status, time to discharge, day 5 peripheral blood oxygenation, day 5 C-reactive protein, and improvement in day 10 clinical status. Between 2 March 2021 and 18 November 2021, 713 patients were enroled in the DMF evaluation, of whom 356 were randomly allocated to receive usual care plus DMF, and 357 to usual care alone. 95% of patients received corticosteroids as part of routine care. There was no evidence of a beneficial effect of DMF on clinical status at day 5 (common odds ratio of unfavourable outcome 1.12; 95% CI 0.86-1.47; p = 0.40). There was no significant effect of DMF on any secondary outcome

PhD

dissertationFollowing gastrulation, the vertebrate hindbrain is transiently segmented into 7 or 8 compartments termed rhombomeres. These compartments play a critical role in the organization of the motor and sensory components of the cranial nerves of the hindbrain. In addition, they are vital to the organization and patterning of the rhombencephalic neural crest, a population of cells that contributes heavily to the formation of craniofacial and pharyngeal structures as well as the ventral body wall. Within the past decade, a number of genes have been identified that function within, and are expressed in segmental fashion along, the embryonic vertebrate hindbrain. Among these are the 3', or anteriorly expressed, members of the Hox gene family. The work presented in this study is an examination of the individual and collective function of four 3' Hox genes, Hoxa1, Hoxa2, Hoxb1 and Hoxb2, in patterning the hindbrain. To accomplish these studies, mice harboring mutations at each of these loci were generated via standard gene targeting techniques and were bred to generate embryos lacking individual or various combinations of these Hox genes. The effects of these mutations on patterning the hindbrain were investigated as well as corresponding defects in the cranial nerves, craniofacial structures, and ventral body wall. The results of these studies provide valuable insights into the importance of hindbrain patterning on neuronal and craniofacial development as well as the mechanisms by which human birth defects such as cleft palate, facial paralysis, and split sternum occur