Structural and mechanistic insights into the CAND1-mediated SCF substrate receptor exchange

Modular SCF (SKP1-CUL1-Fbox) ubiquitin E3 ligases orchestrate multiple cellular pathways in eukaryotes. Their variable SKP1-Fbox substrate receptor (SR) modules enable regulated substrate recruitment and subsequent proteasomal degradation. CAND proteins are essential for the efficient and timely exchange of SRs. To gain structural understanding of the underlying molecular mechanism, we reconstituted a human CAND1-driven exchange reaction of substrate-bound SCF alongside its co-E3 ligase DCNL1 and visualized it by cryo-EM. We describe high-resolution structural intermediates, including a ternary CAND1-SCF complex, as well as conformational and compositional intermediates representing SR- or CAND1-dissociation. We describe in molecular detail how CAND1-induced conformational changes in CUL1/RBX1 provide an optimized DCNL1-binding site and reveal an unexpected dual role for DCNL1 in CAND1-SCF dynamics. Moreover, a partially dissociated CAND1-SCF conformation accommodates cullin neddylation, leading to CAND1 displacement. Our structural findings, together with functional biochemical assays, help formulate a detailed model for CAND-SCF regulation.

707 Principles of Damage Control Surgery in Trauma and Beyond: Experience at A Tertiary Centre

Damage control surgery (DCS) is an abbreviated laparotomy used as a temporising measure in critically unwell patients who have limited physiological reserves to tolerate complex definitive surgeries. The aim of DCS is to address life-threatening haemorrhage and manage abdominal contamination. Following an abbreviated laparotomy, patients are continuously resuscitated in intensive care unit until physiological stability can be maintained for definitive surgeries. The role of DCS in the trauma setting is well-described; however, its principles can also be applied in General Surgery for a variety of indications such as mesenteric ischaemia, uncontrolled haemorrhage, and secondary peritonitis. Judicious selection of the non-trauma patient who will benefit from this strategy is paramount. We present two cases of a polytrauma patient (Patient A), and non-trauma patient with abdominal septic shock (Patient B) who underwent DCS at our tertiary centre. Patient A is a 49-year-old male involved in a road traffic accident who sustained multiple injuries including liver laceration, splenic laceration, and colonic injury. Intra-abdominal packing and repair of serosal tears were performed, with a re-look laparotomy 48 hours later -- no further bleeding or visceral injuries were identified. Patient B is a 51-year-old gentleman who re-presented in septic shock due to infected retroperitoneal collection following a bleeding duodenal ulcer, initially managed radiologically. A T tube was inserted into the duodenum with two abdominal drains at initial DCS. After thorough washout, a feeding jejunostomy was sited at the re-look laparotomy. 30-days mortality is 0% and both patients are under follow-up.

1399 Anorectal Melanoma: Can Be an Unexpected Diagnosis - A Case Report

Anorectal melanoma is a rare tumour. Few cases are reported in the literature. We report a case of 51 years old male complained of anal induration, itching and bloody and suppurative discharge. Patient had symptoms for 2 years. However, patient expected his symptoms are due to recurrence of haemorrhoids. Therefore, he presented late. Then, he had noticed a progressive increase in size, discharge and two opposing ulcers. Patient had no history of abdominal pain, change in bowel habits, bleeding per rectum, history of groin lumps, incontinence nor erectile dysfunction. Patient underwent haemorrhoidectomy about 11 years ago. On examination, there was a circumferential single ulcer eroding the anus extending deep to the dentate line reaching the rectum on digital rectal examination. Also, there was no inguinal lymphadenopathy detected on exam. Incisional biopsy of the ulcer showed anorectal melanoma. Patient had abdominoperineal resection (APR) with adjuvant radiotherapy. At 12 months follow up, there were no signs of recurrence.

Expression of Myoglobin in Normal and Cancer Brain Tissues: Correlation With Hypoxia Markers

Background

Myoglobin (MB) is increasingly recognized as a key player in cancer growth and metastasis. Low oxygen tensions, commonly associated with highly aggressive and recurrent cancers, have been shown to regulate its expression in several cancers such as lung, neck, prostate and breast cancer. However, it is not yet known whether it contributes to the growth and spread of brain cancers especially Glioblastoma multiforme (GBM).

Methods

Here we investigate the expression of MB, and its correlation with the hypoxia markers carbonic anhydrase IX (CAIX) and lactate dehydrogenase A (LDHA), in human tissue microarrays of multiple organ tumors, brain tumors, and GBM tumors, and their respective cancer-adjacent normal tissues. Correlation between MB protein expression and tumor grade was also assessed.

Results

We show that MB protein is expressed in a wide variety of cancers, benign tumors, cancer-adjacent normal tissues, hyperplastic tissue samples and normal brain tissue, and low oxygen tensions modulate MB protein expression in different brain cancers, including GBM. Enhanced nuclear LDHA immune-reactivity in GBM was also observed. Finally, we report for the first time a positive correlation between MB expression and brain tumor grade.

Conclusion

Our data suggest that hypoxia regulate MB expression in different brain cancers (including GBM) and that its expression is associated with a more aggressive phenotype as indicated by the positive correlation with the brain tumor grade. Additionally, a role for nuclear LDHA in promoting aggressive tumor phenotype is also suggested based on enhanced nuclear expression which was observed only in GBM.

Cryo-EM reveals the transition of Arp2/3 complex from inactive to nucleation-competent state

Arp2/3 complex, a crucial actin filament nucleator, undergoes structural rearrangements during activation by nucleation-promoting factors (NPFs). However, the conformational pathway leading to the nucleation-competent state is unclear due to lack of high-resolution structures of the activated state. Here we report a ~3.9 Å resolution cryo-EM structure of activated Schizosaccharomyces pombe Arp2/3 complex bound to the S. pombe NPF Dip1 and attached to the end of the nucleated actin filament. The structure reveals global and local conformational changes that allow the two actin-related proteins in Arp2/3 complex to mimic a filamentous actin dimer and template nucleation. Activation occurs through a clamp-twisting mechanism, in which Dip1 forces two core subunits in Arp2/3 complex to pivot around one another, shifting half of the complex into a new activated position. By showing how Dip1 stimulates activation, the structure reveals how NPFs can activate Arp2/3 complex in diverse cellular processes.

Immune Checkpoint Regulators: A New Era Toward Promising Cancer Therapy

During the last century, our battle against cancer has been inaugurated upon three main approaches; surgery, radiation and chemotherapy. The latest findings on the effectiveness of immunotherapy in cancer management offer a ray of hope after decades of research and studies on the best treatment methods. Immunotherapy has proven effective in the surveillance and destruction of cancer- causing cells, demonstrating its ability to suppress cancer through controlling the wellestablished immune-editing process. Immuno-editing is a process that comprises three principal elements; elimination, equilibrium, and escape, and is paramount to the comprehension of checkpoint inhibition. Cancer cells employ various approaches to evade the elimination step leading to its immune- escape. The escape mechanism encompasses the up-regulation of negative co-signals that block successful activation of cancer-eradicating immune cells, developing cytokine background that favors the immunosuppressive tumor microenvironment (TME), or dropping the expression of tumor- specific proteins known as neo-antigens, therefore reducing the immunogenic activity against cancer cells. Today, checkpoint inhibitors are considered as a primary approach in our fight against cancer. Strategies targeting the inhibitory roles of checkpoint inhibitors have been shown effective against different cancer types and stages, and some already gained the FDA's approval. This review seeks to comprehensively cover the historical background as well as the most recent updates for the role of immune checkpoint regulators in the maintenance of immune homeostatic balance as well as keeping the tumorigenic cells in check.

1093 Multi-modality imaging of a rare cause of constrictive physiology: pericardial ring

Introduction

Proper pathophysiologic diagnosis of constrictive pericarditis (CP) usually mandates utilization of multiple diagnostic tools.

We report a rare cause of constrictive pericarditis in a 33-year-old female presenting with painful epigastric pulsations, easy fatigability, and lower limb edema of 6 months duration. The patient had no past history of trauma, cardiac surgery, or tuberculosis.

Trans-thoracic echocardiography (figure 1, panels A, parasternal long-axis view, and B, apical 4-chamber view) showed an echogenic band (arrow head) across the left (LV) and right (RV) ventricles, with compressed RV cavity. Septal bounce, with shifting of the inter-ventricular septum towards the LV during deep inspiration, was noted; however, Doppler evaluation of the diastolic function was not conclusive of constriction.

Cardiac magnetic resonance (figure 1, panel C) and computed tomography with 3D segmentation, using Materialise Mimics and 3-matic software (figure 1, panel D),showed an 8-mm thick, calcified pericardial ring (arrow head) encircling and indenting both ventricles at mid-cavitary level, resulting in bi-ventricular compression and dumbbell-shaped heart. Both ventricles were of average cavity size, with preserved LV size, systolic function and mildly impaired RV systolic function. Right heart catheterization confirmed the diagnosis of constrictive pericarditis. The patient was referred for surgical pericardiectomy.

Conclusion

Multi-modality imaging is integral for the diagnosis of CP. Our case represents a rare etiology of constrictive physiology.

Abstract 1093 Figure 1

A study to establish international diagnostic reference levels for paediatric computed tomography

The article reports results from the largest international dose survey in paediatric computed tomography (CT) in 32 countries and proposes international diagnostic reference levels (DRLs) in terms of computed tomography dose index (CTDI vol) and dose length product (DLP). It also assesses whether mean or median values of individual facilities should be used. A total of 6115 individual patient data were recorded among four age groups: <1 y, >1-5 y, >5-10 y and >10-15 y. CTDIw, CTDI vol and DLP from the CT console were recorded in dedicated forms together with patient data and technical parameters. Statistical analysis was performed, and international DRLs were established at rounded 75th percentile values of distribution of median values from all CT facilities. The study presents evidence in favour of using median rather than mean of patient dose indices as the representative of typical local dose in a facility, and for establishing DRLs as third quartile of median values. International DRLs were established for paediatric CT examinations for routine head, chest and abdomen in the four age groups. DRLs for CTDI vol are similar to the reference values from other published reports, with some differences for chest and abdomen CT. Higher variations were observed between DLP values, based on a survey of whole multi-phase exams. It may be noted that other studies in literature were based on single phase only. DRLs reported in this article can be used in countries without sufficient medical physics support to identify non-optimised practice. Recommendations to improve the accuracy and importance of future surveys are provided.

The Electrospray Ionization - Mass Spectra of Erythromycin A Obtained from a Marine Streptomyces sp. Mutant

In our ongoing search for production improvements of bioactive secondary metabolites from marine Streptomyces through the induction of mutations using UV light, out of 145 isolates, mutant 10/14 was able to produce potent antibacterial metabolites other than the parent strain as established by chromatographic analysis. Up-scaling fermentation of mutant 10/14, followed by working up and isolation delivered five metabolites, phenazine, 1-acetyl-β -carboline, perlolyrin and erythromycin A, along with an oily substance. The latter two compounds were responsible for the antibacterial activity of the strain. In this article, we discuss with the mutation of the marine Streptomyces sp. AH2, bioactivity evaluation, fermentation and isolation of the microbial metabolites. Moreover, we study to first time in detail the 1D and 2D NMR and ESI MS data including ESI MS² and MS³ patterns combined with HRESI MS of erythromycin A.

Effect of diffusional mass transfer on the performance of horizontal subsurface flow constructed wetlands in tropical climate conditions

The effect of mass transfer on the removal rate constants of BOD5, NH3, NO3 and TKN has been investigated in a Horizontal Subsurface Flow Constructed Wetland (HSSFCW) planted with Phragmites mauritianus. The plug flow model was assumed and the inlet and outlet concentrations were used to determine the observed removal rate constants. Mass transfer effects were studied by assessing the influence of interstitial velocity on pollutant removal rates in CW cells of different widths. The flow velocities varied between 3-46 m/d. Results indicate that the observed removal rate constants are highly influenced by the flow velocity. Correlation of dimensionless groups namely Reynolds Number (Re), Sherwood Number (Sh) and Schmidt Number (Sc) were applied and log-log plots of rate constants against velocity yielded straight lines with values beta = 0.87 for BOD5, 1.88 for NH3, 1.20 for NO3 and 0.94 for TKN. The correlation matched the expected for packed beds although the constant beta was higher than expected for low Reynolds numbers. These results indicate that the design values of rate constants used to size wetlands are influenced by flow velocity. This paper suggests the incorporation of mass transfer into CW design procedures in order to improve the performance of CW systems and reduce land requirements.

Bioactive benzopyrone derivatives from new recombinant fusant of marine Streptomyces

In our searching program for bioactive secondary metabolites from marine Streptomycetes, three microbial benzopyrone derivatives (1-3), 7-methylcoumarin (1) and two flavonoides, rhamnazin (2) and cirsimaritin (3), were obtained during the working up of the ethyl acetate fraction of a marine Streptomyces fusant obtained from protoplast fusion between Streptomyces strains Merv 1996 and Merv 7409. The structures of the three compounds (1-3) were established by nuclear magnetic resonance, mass, UV spectra, and by comparison with literature data. Marine Streptomyces strains were identified based on their phenotypic and chemotypic characteristics as two different bioactive strains of the genus Streptomyces. We described here the fermentation, isolation, as well as the biological activity of these bioactive compounds. The isolated compounds (1-3) are reported here as microbial products for the first time.

Conventional in-vitro fertilisation versus intracytoplasmic sperm injection for the treatment of non-male-factor infertility: a randomised controlled trial

BACKGROUND

Intracytoplasmic sperm injection (ICSI) is a more invasive option than conventional in-vitro fertilisation (IVF), which can be successful even when semen characteristics are poor. Reports of higher fertilisation rates after ICSI suggest that this technique may be better than the conventional method for all couples seeking IVF. We undertook a multicentre randomised controlled trial comparing clinical outcome after ICSI or traditional IVF in couples with non-male-factor infertility.

METHODS

415 eligible and consenting couples at four UK centres were randomly assigned IVF or ICSI (total 435 treatment cycles: IVF 224; ICSI 211). Usual clinical and laboratory protocols for the two treatment procedures were followed in each of four participating centres. The primary outcome was the implantation rate (number of gestation sacs per embryo replaced expressed as a percentage). Secondary outcomes were pregnancy and fertilisation rates associated with each treatment. Analyses were by intention to treat.

FINDINGS

The implantation rate was higher in the IVF group than in the ICSI group (95/318 [30%] vs 72/325 [22%]; relative risk 1.35 [95% CI 1.04-1.76]). The pregnancy rate per cycle was also higher after IVF (72 [33%] vs 53 [26%]; 1.17 [0.97-1.35]). Mean associated laboratory time was significantly shorter with IVF than with ICSI (22.9 [SD 12.1] vs 74.0 [38.1] min; 95% CI for difference 45.6-56.6).

INTERPRETATION

ICSI offers no advantage over IVF in terms of clinical outcome in cases of non-male-factor infertility. Our results support the current practice of reserving ICSI only for severe male-factor problems.

The effect of ammonia on olfactory epithelium and vomeronasal organ neuroepithelium of rabbits. A histological and histochemical study

In recent studies, the vomeronasal organ (VNO), although vestigial and with unknown function in humans, was reported to be present in almost every person examined. In rabbits, it is a well-developed organ, one lying on each side of the nasal septum. Histologically it was found to contain neuroepithelium which is considered an accessory olfactory system taking charge of an olfactory discrimination different from that of olfactory epithelium. Experimental removal of the VNO in male animals reduces reproductive performance and aggression. In this study, the effects of prolonged exposure to ammonia vapor on the histological pattern and enzymatic activity of the olfactory epithelium and the VNO neuroepithelium of 30 adult male rabbits were investigated and compared with a control group. In the exposed animals, the supporting cells in both types of epithelia showed hyperplasia which was more marked in the olfactory epithelium. Manifestations of cytotoxicity were found more in the bipolar cells of the olfactory epithelium than in the VNO neuroepithelium. The enzymatic activity in the exposed group supported the histological results. The presence of the VNO neuroepithelium of the rabbit in a narrow duct with a minute nasal orifice could have some protective effects on the cells.

Contraceptives for lactating women: a comparative trial of a progesterone-releasing vaginal ring and the copper T 380A IUD

From approximately one week before normal ovulation resumes, lactating women require protection against pregnancy by a contraceptive that is safe for both infant and mother in a multicenter one-year study, the natural hormone, progesterone, delivered vaginally by a sequence of four contraceptive rings designed for continuous use, was evaluated as a contraceptive for nursing mothers in comparison with the Copper T 380A IUD. Individual rings release in effective average dose of 10 mg day for a 3 month period. Evaluation included measures of lactational performance as well as of contraceptive efficacy and safety to mother and child. Nine participating clinics enrolled 802 ring users and 734 IUD acceptors between postpartum days 29 and 63. Life table analyses were performed with parallel decrements for ring and IUD subjects. Continuation in the study and analysis required that subjects not stop breastfeeding. The ring, with a one-year pregnancy rate of 1.5 per 100, did not differ significantly from the IUD with respect to contraceptive effectiveness (p > 0.05). More than half of the ring subjects were continuing at 6 months post admission and a quarter (23.5 per hundred) were still using the ring and breastfeeding one year after admission. Women with the IUD, however, had higher continuation rates (p < 0.001) at both time points. The largest single decrement for each method was that for weaning. Ring users had more complaints of vaginal problems but had fewer vaginal disorders on examination. At 12 months postpartum, 46 per 100 continuing ring users remained in amenorrhea. Lactation performance and the health and weight gain of the infants were similar among users of either regimen.

A randomized trial of the Gyne T 380 and Gyne T 380 Slimline Intrauterine Copper devices

To facilitate manufacture and insertion of the Gyne T 380 IUD, design changes were instituted. Copper collars were seated flush at the ends of the horizontal crossbar of the device. A randomized study of the Gyne T 380 Slimline, the new design, was undertaken in comparison with the standard Gyne T 380. A total of 996 women were enrolled, with 698 Slimline insertions and 298 of the standard Gyne T. No statistically significant difference in ease of insertion or in performance was detected between the models. At one year, the pregnancy rate of each model was below 0.5 per 100 and the continuation rate was 79-80 per 100. Pelvic inflammatory disease or endometritis was found in one percent of subjects in the first year. This is the seventh multicenter randomized study of a collared T IUD with 380 mm2 of copper surface. In all seven, the one-year gross pregnancy rate has been 1.2 per 100 or lower.

Assessing the acceptability of NORPLANT implants in four countries: findings from focus group research

In 1986-87, a qualitative research project was conducted in the Dominican Republic, Egypt, Indonesia, and Thailand to expand understanding of the acceptability of NORPLANT contraceptive implants beyond inferences made on the basis of continuation rates. In each of the four study sites, focus group discussions or in-depth interviews were held with potential acceptors, current NORPLANT users, discontinuers, husbands of women in these three groups, and service providers. Nonclinical participants generally had little formal education and lived primarily in urban or semi-urban areas where NORPLANT has been available for at least five years. The study focused on attitudes, perceptions, and experiences of each group regarding NORPLANT implants. Results suggest that factors having an impact on the acceptability of NORPLANT implants fall into three general categories: medical/technical, cultural/religious, and informational/educational. This article discusses each of these categories, including programmatic implications of the findings, and puts forward recommendations for enhancing NORPLANT introduction efforts on the basis of these findings.

Anopheles sergenti (Theobald) a potential malaria vector in Egypt

Two immunoassays for malaria sporozoite detection and identification, the immunoradiometric assay (IRMA) and the enzyme-linked immunosorbent assay (ELISA) using the species-specific monoclonal antibodies are routinely performed in our laboratory. We analyzed (573) anopheline mosquitoes of A. sergenti (463), A. pharoensis (81) and A. multicolor (29) collected from Siwa-oases and Faiyum Governorate (two known active malaria foci in Egypt), for detection of P. falciparum and P. vivax sporozoites. P. falciparum sporozoites were detected by both IRMA and ELISA tests in two A. sergenti mosquitoes (one from Siwa 1/389 = (0.26%) and one from Faiyum Governorate 1/74 = (1.35%)). No P. vivax sporozoites were detected. This finding is important in explaining the malaria transmission and provide first incrimination of An. sergenti as the responsible vector of malaria in Siwa-oasis, Egypt.