50 research outputs found
Endogenous RNA editing records the transcriptional history of human cells
No full textObtaining continuous measurements of transcriptional activity across the
transcriptome would unveil a granularity of information about cell regulation not
currently possible. RNA sequencing, however, takes a snapshot of the transcriptome at an
instant and is destructive, preventing further sampling. From the point of transcription until
degradation, mRNA gradually accumulates adenosine-to-inosine edits due to the activity of
ADAR enzymes, potentially providing an endogenous record of mRNA age. Determining the
age distribution of transcripts present within a cell would allow one to infer the cell’s recent
transcriptional record.
In this work, I find that endogenous A-to-I editing of RNA transcripts in unmodified human
cells serves as a molecular recorder, allowing us to infer the ages of endogenous RNA
transcripts at the single molecule level with precision on the order of hours. Using a
controlled gene expression system, I show that the distribution of ages of a transcript encode
past transcriptional history, information which is not found in static RNA sequencing. I show
that Timestamps can recover the transcriptional dynamics of hundreds of genes in
diRerentiating primary human monocytes, even identifying new putative regulators of
human monocyte diRerentiation. In dividing single cells, I show that the periodic
transcription of S- and G2/M-phase associated genes, as recorded by Timestamps, tracks
the period of the cell cycle.
By sorting the single neurons, Timestamps could enable RNA sequencing to identify which
neurones respond to diverse but temporally separated stimuli, thus enabling highthroughput
functional brain mapping. I begin developing an in vivo experiment to show that
Timestamps can trace the production of immediate early genes and thereby infer the past
activity of neurons.
Finally, to improve Timestamps and extend its functionality to non-primate model
organisms, I invent a new class of promiscuous, hyperactive RNA editors.
Timestamps is an endogenous molecular recorder of transcriptional history
Value of duplex scanning in differentiating embolic from thrombotic arterial occlusion in acute limb ischemia
No full textObturator hernia: A case report and review of the literature
No full textAbstractINTRODUCTIONAn obturator hernia is a rare condition but is associated with the highest mortality of all abdominal wall hernias. Early surgical intervention is often hindered by clinical and radiological diagnostic difficulty. The following case report highlights these diagnostic difficulties, and reviews the current literature on management of such cases.PRESENTATION OF CASEWe present the case of an 86-year-old lady who presented with intermittent small bowel obstruction, clear hernial orifices, and right medial thigh pain. Pre-operative CT imaging was suggestive of an obstructed right femoral hernia. However, intra-operatively the femoral canal was clear and an obstructed hernia was found passing through the obturator foramen lying between the pectineus and obturator muscles in the obturator canal.DISCUSSIONObturator hernias are notorious for diagnostic difficulty. Patients often present with intermittent bowel obstruction symptoms due to a high proportion exhibiting Richter's herniation of the bowel. Hernial sacs can irritate the obturator nerve within the canal, manifesting as medial thigh pain, and often no hernial masses can be detected on clinical examination. Increasing speed of diagnosis through early CT imaging has been shown to reduce the morbidity and mortality associated with obturator hernias. However, over-reliance on CT findings should be cautioned, as imaging and operative findings may not always correlate.CONCLUSIONA high suspicion for obturator hernia should be maintained when assessing a patient presenting with bowel obstruction particularly where intermittent symptoms or medial thigh pain are present. Rapid clinical and appropriate radiological assessment, followed by early surgery is critical to successful treatment
Incidence and predictors of post-catheterization femoral artery pseudoaneurysms
No full textAbstractBackgroundFemoral artery pseudoaneurysm (FAP) is a troublesome complication after transfemoral catheter procedures. The incidence and predictors of FAP as a separate entity have not been extensively studied.AimDetect prospectively the incidence and predictors of post catheterization FAP.MethodsFrom June 2009 till June 2011, we prospectively included all patients who underwent catheterization from the femoral approach. Duplex ultrasound was performed in cases with clinical suspicion of vascular complications. Clinical data and procedural variables were compared with a control group of 200 randomly selected patients. We performed univariate analysis and a logistic regression model for multivariate analysis.ResultsThe incidence of FAP was 3.42%. Eighty FAPs (66.7%) were related to a diagnostic catheterization while 40(33.3%) were related to an interventional procedure. The mean age of patients with FAP was 55.36±10.68yrs; 57.5% were females. At diagnosis 81.66% of the patients were on antiplatelet therapy, 35% were on heparin or warfarin and 16.66% were on both, with mean value of INR for patients on warfarin 2.2±0.76. FAPs were connected to the common femoral artery in 29.1% of patients, to the SFA in 54.1% and to the profunda in 16.6%. Female gender, obesity and hypertension significantly enhanced the risk for FAP. Also diagnostic angiography, low puncture, multiple punctures and the use of dual antiplatelet and/or anticoagulant therapy were independent procedure-related risk factors for FAP.ConclusionFemoral artery pseudoaneurysms are not uncommon. Female gender, obesity, hypertension, the use of antiplatelet and/or anticoagulant therapy and faulty puncture techniques are independent risk factors for FAPs
Seasonal variations of hydration status of professional soccer players in Saudi Arabia during training sessions and match play
No full textSoccer is the most widely played sport in the world. Consequently, players train and compete in a wide variety of environmental conditions. Professional soccer players normally train daily and compete once or twice a week. Exercise hot environments can lead to dehydration because sweat losses often exceed fluid intake. Sweat rate can range between 1 to 2.5 L.h-1 depending on factors such as environment conditions, fitness and clothing. Previous studies of soccer players have found that players are often dehydrated.
This thesis consists of three studies conducted in Riyadh, Saudi Arabia. Young Saudi professional soccer players based at the Al Hilal club were recruited to the study. The author worked them during their training and matches at different periods during the year to study the effects of exercise in warm and cool conditions. Their hydration status was studied using a range of methods including analysis of the blood and urine. The main aims of these experiments were to examine the effect of exercise intensity in temperate and hot environments on blood, urine, core body temperature and aldosterone concentrations.
The first study evaluated their hydration status over three days of training and one match in temperate conditions. The aim of this study was to establish that research could be conducted as players went through their normal routines determined by the club management and coaches. Change in body weight, serum osmolality and electrolytes, sweat loss, fluid intake and aldosterone concentrations were measured. The range of ambient temperatures was between 23.4 and 30.6 oC and the relative humidity ranged between 14.2 and 23.2 %. Eleven Saudi professional soccer players participated in this study. Their body weight significantly decreased during exercise. Serum osmolality was always high indicating dehydration. It increased significantly during match play, from pre 288 ± 3 mOsm/kg to 293 ± 4 mOsm/kg. Day by day changes of serum osmolality before training sessions and match were small and on some days statistically significant. Plasma aldosterone concentrations significantly increased after the match. The magnitude of dehydration was affected by the intensity of the training sessions GPS was used to measure distance covered. Players covered more distance in match play (7326 m) than in training sessions. Core body temperature was elevated during exercise but not to dangerous levels.
The second study was aimed to repeat these measurements in the summer time during the early season in September. Again, three training sessions and one match were studied. The environment conditions were above 35 oC on all days and the relative humidity was between 10.5 and 13.0 %. The success of the first study in establishing a good relationship allowed some expansion and sixteen soccer players were recruited. Similar results were obtained and fluid losses were greater in the hotter conditions. None of the players replaced all of the fluid lost in training sessions or match play. The mean of sweat rate was 1932 ± 512 ml.h-1 and players dehydrated by 1.8 ± 0.7 % during match play. The serum sodium concentrations were small but statistically significant for some sessions. Similar changes were seen in serum osmolality. Estimated urine osmolality and specific gravity values were high on all days. Plasma aldosterone concentrations increased significantly during two training sessions and match play. On all days the mean of core temperature during exercise increased significantly.
The third study aimed to improve hydration in a group of players before they started training. Responses were compared in hydration intervention (HI) and hydration control (HC) groups. Each group comprised of eight soccer players. The ambient temperature during this study was about 29 oC. Measurements were taken on three days; the first day was as base line. Next two days, intervention group were instructed to consume 500 ml before attending the club. Independent t-test showed no significant differences between the two groups in base line of age, body weight, height and BMI (P > 0.05). Blood, urine, intensity of exercise, aldosterone and core body temperature were measured between groups. Serum electrolyte concentrations were not different in the two groups on three days. The serum osmolality of HI was significantly lower than HC before training two (T2) during the study (P < 0.05). No differences in fluid intake were observed during training and sweat rate and loss did not differ during training sessions in the two groups. In addition, serum osmolality did not change after T2 in HI, where the control group had significant increase in osmolality after this training session (P < 0.05). On the third day, serum osmolality did not differ between the two groups. However, after exercise serum osmolality elevated from pre to post exercise. The HI group had lower aldosterone concentrations before T2 started than HC group (P < 0.05). The core temperatures rose during exercise in both groups and there were no differences between the two groups.
In conclusion, the three studies were completed successfully. Good data were obtained and it was possible to conduct research with the players as they followed their normal routines of training and playing. These data showed that the players were dehydrated before and during training and match play. Sweat loss was greater in hot conditions than in temperate conditions. Serum osmolality elevated after exercise in hot and temperate conditions and by different intensity of exercise. Plasma aldosterone concentrations were affected by the exercise in all studies
Why articles continue to be cited after they have been retracted : An audit of retraction notices
No full textBackground: Papers continue to be cited by authors even after they have been retracted. Retraction notices provide readers with information about retracted papers and may help minimise post-retraction citation. To date, a review of the quality of retraction notices in nursing science has not been reported. Design: An audit of retraction notices associated with 29 retracted manuscripts published in nursing science journals. Methods: Retraction notices were reviewed again using the Committee on Publication Ethics (COPE) guidelines. Results: In total, 28 retraction notices were retrieved and reviewed (one retracted paper did not have a retraction notice). Details of the retracted manuscripts were included in all reviewed notices and, in all but two, author names were reported. Details of the time between a paper being published and retracted were not reported and generally there was a little information in notices about how the retraction decisions were made. All retraction notices were freely available. Seven notices stated who had made the decision to retract. Twenty-two (77%) notices stated the reason for retraction. Notices were brief and contained factual information. The webpages of three retracted articles did not clearly indicate that the paper had been retracted. Conclusion: More detailed and informative retraction notices will inform readers and may help reduce post- retraction citation
Enhancing lignite coal quality with biomass waste in slow pyrolysis Fischer-Tropsch reactor
No full textCoal is a non-renewable natural resource that is widely used in thermal power plants in major industrialized countries. Most of the world's coal contains a high percentage of moisture and ash and a low caloric value. The slow pyrolysis process of coal improves its quality and significantly reduces its smoke and ash. In this study, Soma Kisrakdere lignite coal in Manisa province in Turkey with some biomass wastes (peanut shells, pine cones, and olive seeds) was evaluated by applying a slow pyrolysis process using a Fischer-Tropisch reactor. Firstly, Soma Kisrakdere lignite alone, then each waste biomass was mixed with lignite coal at weight percentages of 10 %, 25 %, and 50 % to form three mixtures for each biomass waste. The process temperature was 500°C, and the temperature rate was 0.1 °C/s. The findings obtained in this study showed that with the increase of weight percentages of biomass which added from biomass waste to lignite coal, the productivity of coal (biochar) decreased and the products of tar, decomposed water, and gases increased. As for calories, its value increased with the increase in weight of the addition the waste of biomass which added where 50 % of biomass additions were the highest value of low heating value (LHV) and high heating value (HHV) and most effective than others which added to lignite coal. Among the biomass residues used, the olive seeds were the most valuable, compared with the peanut shells and pine cones. © 2024 The Author
Three-dimensional versus standard miniplate fixation in the management of mandibular angle fractures : a systematic review and meta-analysis
No full textThe aim of the present study was to test whether there is a significant difference in the clinical outcomes between standard and three-dimensional (3D) miniplate fixation in the management of mandibular angle fractures (MAFs). An electronic search without date and language restrictions was performed in October 2013. Inclusion criteria were studies in humans including randomized controlled trials, controlled clinical trials, and retrospective studies, with the aim of comparing the two techniques. Six studies were included. The meta-analyses revealed statistically significant differences for the incidence of hardware failure and postoperative trismus. There were no significant differences in the incidence of postoperative infection, malocclusion, wound dehiscence, non-union/malunion, or paresthesia. The cumulative odds ratio was 0.42, meaning that the use of 3D miniplates in the fixation of MAFs decreases the risk of the event (postoperative complication) by 58%. The results of this meta-analysis showed lower postoperative complication rates with the use of 3D miniplate fixation in comparison with the use of standard miniplate fixation in the management of MAFs
Value of duplex scanning in differentiating embolic from thrombotic arterial occlusion in acute limb ischemia
No full textRecent Advances in Stem Cell Therapy for Limbal Stem Cell Deficiency: A Narrative Review
No full text\ua9 2020, The Author(s). Destruction of the limbus and depletion of limbal stem cells (LSCs), the adult progenitors of the corneal epithelium, leads to limbal stem cell deficiency (LSCD). LSCD is a rare, progressive ocular surface disorder which results in conjunctivalisation and neovascularisation of the corneal surface. Many strategies have been used in the treatment of LSCD, the common goal of which is to regenerate a self-renewing, transparent, and uniform epithelium on the corneal surface. The development of these techniques has frequently resulted from collaboration between stem cell translational scientists and ophthalmologists. Direct transplantation of autologous or allogeneic limbal tissue from a healthy donor eye is regarded by many as the technique of choice. Expansion of harvested LSCs in vitro allows smaller biopsies to be taken from the donor eye and is considered safer and more acceptable to patients. This technique may be utilised in unilateral cases (autologous) or bilateral cases (living related donor). Recently developed, simple limbal epithelial transplant (SLET) can be performed with equally small biopsies but does not require in vitro cell culture facilities. In the case of bilateral LSCD, where autologous limbal tissue is not available, autologous oral mucosa epithelium can be expanded in vitro and transplanted to the diseased eye. Data on long-term outcomes (over 5 years of follow-up) for many of these procedures is needed, and it remains unclear how they produce a self-renewing epithelium without recreating the vital stem cell niche. Bioengineering techniques offer the ability to re-create the physical characteristics of the stem cell niche, while induced pluripotent stem cells offer an unlimited supply of autologous LSCs. In vivo confocal microscopy and anterior segment OCT will complement impression cytology in the diagnosis, staging, and follow-up of LSCD. In this review we analyse recent advances in the pathology, diagnosis, and treatment of LSCD
