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1.
Transplant Direct ; 10(6): e1633, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38807861

ABSTRACT

Background: Ex vivo kidney perfusion is an evolving platform that demonstrates promise in preserving and rehabilitating the kidney grafts. Despite this, there is little consensus on the optimal perfusion conditions. Hypothermic perfusion offers limited functional assessment, whereas normothermic perfusion requires a more complex mechanical system and perfusate. Subnormothermic machine perfusion (SNMP) has the potential to combine the advantages of both approaches but has undergone limited investigation. Therefore, the present study sought to determine the suitability of SNMP for extended kidney preservation. Methods: SNMP at 22-25 °C was performed on a portable device for 24 h with porcine kidneys. Graft assessment included measurement of mechanical parameters and biochemical analysis of the perfusate using point-of-care tests. To investigate the viability of kidneys preserved by SNMP, porcine kidney autotransplants were performed in a donation after circulatory death (DCD) model. SNMP was also compared with static cold storage (SCS). Finally, follow-up experiments were conducted in a subset of human kidneys to test the translational significance of findings in porcine kidneys. Results: In the perfusion-only cohort, porcine kidneys all displayed successful perfusion for 24 h by SNMP, evidenced by stable mechanical parameters and biological markers of graft function. Furthermore, in the transplant cohort, DCD grafts with 30 min of warm ischemic injury demonstrated superior posttransplant graft function when preserved by SNMP in comparison with SCS. Finally, human kidneys that underwent 24-h perfusion exhibited stable functional and biological parameters consistent with observations in porcine organs. Conclusions: These observations demonstrate the suitability and cross-species generalizability of subnormothermic machine perfusion to maintain stable kidney perfusion and provide foundational evidence for improved posttransplant graft function of DCD kidneys after SNMP compared with SCS.

2.
J Educ Teach Emerg Med ; 9(1): S1-S41, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38344051

ABSTRACT

Audience: This simulation is intended for 4th year medical students. Background: Shock is the result of inadequate circulation and failure to perfuse tissues, leading to cellular and organ dysfunction.1 Anaphylactic shock specifically is a type of distributive shock secondary to an IgE (immunoglobulin E) dependent reaction, which can result in respiratory compromise and cardiovascular collapse. The National Institute of Allergy and Infectious Diseases/Food Allergy and Anaphylaxis Network (NIAID/FAAN) laid out three diagnostic criteria for the diagnosis of anaphylaxis. Fulfillment of any one of the three following criteria likely indicates anaphylaxis: 1) acute onset of illness with skin findings and either respiratory compromise or reduced blood pressure, 2) involvement of two or more organ systems after exposure to a likely allergen, 3) reduced blood pressure after exposure to a known allergen.2 While not a required component of the pathology, hives and cutaneous findings often prompt clinicians to consider anaphylaxis in their differential diagnosis. However, skin findings are absent in 10-20% of cases of anaphylaxis.3 It is therefore important for physicians to quickly recognize anaphylactic shock and begin appropriate management in a timely manner even in the absence of skin findings. A previous study of fatal anaphylactic reactions showed a median time to respiratory or cardiac arrest as 30 minutes for foods, 15 minutes for envenomations, and five minutes for iatrogenic reactions.4 Drugs are the most common reported cause of fatal anaphylaxis in the United States,5 and penicillin allergy is the most common drug allergy reported by patients.6 This simulation will help learners recognize an atypical presentation of anaphylactic shock, encourage them to consider anaphylaxis in their differential diagnosis for decompensated patients, and reinforce the correct management of anaphylaxis. Educational Objectives: At the conclusion of the simulation, learners will be able to: 1) demonstrate ability to efficiently review patient records to optimize patient care and identify relevant details to current presentation, 2) rapidly assess a patient when there is a change in clinical status, 3) recognize the need to start resuscitative fluids for undifferentiated hypotension, 4) identify anaphylaxis, 5) demonstrate the medical management of anaphylaxis, 6) utilize the I-PASS framework to communicate with the inpatient team during the transition of care. Educational Methods: This summative simulation was designed to assess competence in two of the core Entrustable Professional Activities (EPAs), as defined by the Association of American Medical Colleges (AAMC). These include EPA 8 (Give or Receive a Patient Handover to Transition Care Responsibility) and EPA 10 (Recognize a Patient Requiring Urgent or Emergent Care and Initiate Evaluation and Management). It was performed with 4th year medical students at the conclusion of their month-long emergency medicine (EM) clerkship. This scenario joined seven other scenarios in our pool of potential cases. These sessions are conducted using a high-fidelity manikin as the patient and a confederate/actor in the nursing role. After each scenario concludes, there is a post-simulation debriefing session on the presentation, differential diagnosis, physical exam findings, and management of the target pathology. A Gather-Analyze-Summarize technique was used for the debriefing session.7. Research Methods: Facilitators provided informal feedback to the scenario developers after the case was introduced into the assessment rotation. Learners completed a standard evaluation issued by the College of Medicine for the entire session, rather than for individual scenarios. These evaluations were reviewed in aggregate for the first year of implementation. Over this time frame, approximately half the students were run through this scenario. Results: Overall, our facilitators felt the case fit well into our pool of simulation cases. They felt they were adequately able to assess the students' ability to respond to a decompensating patient and thought the difficulty level was appropriate for 4th year medical students. The simulation assessment exercise as a whole was highly rated by the students. Of the 198 students who completed an evaluation, 93% rated the overall quality of the session as Very Good or Excellent. Discussion: Our department has run formative simulations during the 4th year EM clerkship for over ten years. Our primary objective is to assess 4th year students' competence in EPA 10 (Recognize a Patient Requiring Urgent or Emergent Care and Initiate Evaluation and Management). This case was developed to replace another scenario of anaphylaxis which was felt to be too straightforward and easier than other scenarios in our repertoire. By making the scenario more difficult and the presentation of anaphylaxis a bit atypical, we were able to reinforce the need to include anaphylaxis in the differential diagnosis for any patient who rapidly decompensates. We are also able to review the diagnostic criteria for anaphylaxis and the appropriate treatment, including stopping the exposure to the antigen. This simulation proved to be highly engaging for 4th year medical students, and students seemed to perform at a similar level as previous summative simulations. Overall, we felt this simulation successfully achieved the objectives of the simulation session as a whole, and it was integrated into our 4th year EM clerkship simulation curriculum. Topics: Medical simulation, emergency medicine, anaphylaxis, anaphylactic shock, allergic reaction, penicillin allergy.

3.
J Educ Teach Emerg Med ; 8(4): S49-S79, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37969154

ABSTRACT

Audience: This scenario was developed to educate emergency medicine residents on the diagnosis and management of patients with an inhalational airway injury secondary to a house fire. Background: Burn injuries are a common occurrence encountered by the emergency physician. According to the National Hospital Ambulatory Medical Care Survey, around 371,000 patients were treated in emergency departments for fire or burn injuries across the United States in 2020. This represents around 1% of emergency department visits related to injury, poisoning, or adverse effects.1 One of the most dangerous and time critical aspects of managing severely burned patients is inhalation injury. Inhalation injury is a relatively vague term which may refer to pulmonary exposure to a wide range of chemicals in various forms. In the context of burn patients, this is most often smoke exposure. It is critical that the emergency medicine provider rapidly identifies the potential for an inhalational injury in order to determine the need for definitive airway management. It is also important that the provider has the necessary skills and systematic approach to manage what is likely to be a difficult airway. Furthermore, providers must then have the knowledge of how to best manage and resuscitate these severely burned patients post-intubation. Educational Objectives: At the conclusion of the simulation session, learners will be able to: 1) recognize the indications for intubation in a thermal burn/inhalation injury patient; 2) develop a systematic approach to an inhalational injury airway; and 3) recognize indications for transfer to burn center. Educational Methods: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of inhalational airway injury secondary to a house fire. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case. Research Methods: Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. The local institution's simulation center's electronic feedback form is based on the Center of Medical Simulation's Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form2 with the inclusion of required qualitative feedback if an element was scored less than a 6 or 7. Results: Nine learners completed a feedback form. This session received all 6 & 7 scores (consistently effective/very good and extremely effective/outstanding, respectively) other than one isolated 5 score. Discussion: This is a cost-effective method for reviewing inhalational airway injury diagnosis and management. The case may be modified for targeted audiences, expected resources, and learning objectives, such as removal of a bronchoscope availability in settings which are expected to be resource-limited. Some readers may choose to focus on other aspects of burn management instead of airway securement such as cyanide and/or carbon monoxide toxicity. We encourage readers to limit the number of learning objectives because airway algorithms and troubleshooting for this scenario was a rich, stand-alone debriefing. There was not enough time to review in detail all nuanced aspects of the burned patient, including: Lund-Browder versus rule of 9's, modified Brooke versus Parkland formulas, indications for and completion of escharotomies, and/or identification and treatment of cyanide and carbon monoxide toxicity. Topics: Medical simulation, burns, airway emergencies, emergency medicine.

4.
Curr Biol ; 33(14): 3031-3040.e6, 2023 07 24.
Article in English | MEDLINE | ID: mdl-37379844

ABSTRACT

Centrosomes are multi-protein organelles that function as microtubule (MT) organizing centers (MTOCs), ensuring spindle formation and chromosome segregation during cell division.1,2,3 Centrosome structure includes core centrioles that recruit pericentriolar material (PCM) that anchors γ-tubulin to nucleate MTs.1,2 In Drosophila melanogaster, PCM organization depends on proper regulation of proteins like Spd-2, which dynamically localizes to centrosomes and is required for PCM, γ-tubulin, and MTOC activity in brain neuroblast (NB) mitosis and male spermatocyte (SC) meiosis.4,5,6,7,8 Some cells have distinct requirements for MTOC activity due to differences in characteristics like cell size9,10 or whether they are mitotic or meiotic.11,12 How centrosome proteins achieve cell-type-specific functional differences is poorly understood. Previous work identified alternative splicing13 and binding partners14 as contributors to cell-type-specific differences in centrosome function. Gene duplication, which can generate paralogs with specialized functions,15,16 is also implicated in centrosome gene evolution,17 including cell-type-specific centrosome genes.18,19 To gain insight into cell-type-specific differences in centrosome protein function and regulation, we investigated a duplication of Spd-2 in Drosophila willistoni, which has Spd-2A (ancestral) and Spd-2B (derived). We find that Spd-2A functions in NB mitosis, whereas Spd-2B functions in SC meiosis. Ectopically expressed Spd-2B accumulates and functions in mitotic NBs, but ectopically expressed Spd-2A failed to accumulate in meiotic SCs, suggesting cell-type-specific differences in translation or protein stability. We mapped this failure to accumulate and function in meiosis to the C-terminal tail domain of Spd-2A, revealing a novel regulatory mechanism that can potentially achieve differences in PCM function across cell types.


Subject(s)
Cytoskeletal Proteins , Drosophila Proteins , Drosophila , Gene Duplication , Tubulin , Animals , Male , Centrioles/genetics , Centrioles/metabolism , Centrosome/metabolism , Drosophila/genetics , Drosophila/metabolism , Meiosis , Mitosis , Tubulin/metabolism , Cytoskeletal Proteins/genetics , Drosophila Proteins/genetics
5.
Front Med (Lausanne) ; 9: 804834, 2022.
Article in English | MEDLINE | ID: mdl-35280912

ABSTRACT

Background: Subnormothermic machine perfusion (SNMP) of liver grafts is currently less clinically developed than normothermic and hypothermic approaches, but may have logistical advantages. At intermediate temperatures, the oxygen demand of the graft is low enough to be satisfied with an acellular perfusate, obviating the need for oxygen carrying molecules. This intermediate metabolic rate, however, is sufficient to support the production of bile, which is emerging as an important indicator of graft injury and viability. In this study, we hypothesized that the biliary compartment would be more sensitive than perfusate in detecting graft injury during SNMP. Methods: To test this hypothesis in a rat model, we performed liver transplants with DCD and control liver grafts after 1 h of acellular room temperature machine perfusion (acRTMP) or static cold storage (SCS). Point of care liver function tests were measured in biliary and perfusate samples after 1 h of machine perfusion. Following transplantation, rats were sacrificed at 24 h for assessment of post-transplant graft function and histology. Results: All point-of-care liver function tests were significantly more concentrated in the biliary compartment than the perfusate compartment during acRTMP. DCD liver grafts could be distinguished from control liver grafts by significantly higher markers of hepatocyte injury (AST, ALT) in the biliary compartment, but not in the perfusate compartment. Classical markers of cholangiocyte injury, such as gammy-glut amyl transferase (GGT), amylase (AML), and alkaline phosphatase were detectable in the biliary compartment, but not in the perfusate compartment. In comparison to SCS, graft preservation by acRTMP produced a significant survival benefit in DCD liver transplantation (75 vs. 0%, p < 0.0030). Conclusion: Together, these findings demonstrate that during acRTMP, the biliary compartment may be a more sensitive indicator of graft injury than the perfusate compartment. Moreover, acRTMP provides superior graft preservation to SCS in rat DCD liver transplantation.

6.
Development ; 149(7)2022 04 01.
Article in English | MEDLINE | ID: mdl-35297981

ABSTRACT

Microcephaly is a failure to develop proper brain size and neuron number. Mutations in diverse genes are linked to microcephaly, including several with DNA damage repair (DDR) functions; however, it is not well understood how these DDR gene mutations limit brain size. One such gene is TRAIP, which has multiple functions in DDR. We characterized the Drosophila TRAIP homolog nopo, hereafter traip, and found that traip mutants (traip-) have a brain-specific defect in the mushroom body (MB). traip- MBs were smaller and contained fewer neurons, but no neurodegeneration, consistent with human primary microcephaly. Reduced neuron numbers in traip- were explained by premature loss of MB neuroblasts (MB-NBs), in part via caspase-dependent cell death. Many traip- MB-NBs had prominent chromosome bridges in anaphase, along with polyploidy, aneuploidy or micronuclei. Traip localization during mitosis is sufficient for MB development, suggesting that Traip can repair chromosome bridges during mitosis if necessary. Our results suggest that proper brain size is ensured by the recently described role for TRAIP in unloading stalled replication forks in mitosis, which suppresses DNA bridges and premature neural stem cell loss to promote proper neuron number.


Subject(s)
Microcephaly , Mushroom Bodies , Animals , DNA Repair , Drosophila , Microcephaly/genetics , Neurogenesis
7.
Acc Chem Res ; 54(20): 3792-3803, 2021 Oct 19.
Article in English | MEDLINE | ID: mdl-34623803

ABSTRACT

ConspectusDue to the spatial confinement, two-dimensional metal chalcogenides display an extraordinary optical response and carrier transport ability. Solution-based synthesis techniques such as colloidal hot injection and ion exchange provide a cost-effective way to fabricate such low-dimensional semiconducting nanocrystals. Over the years, developments in colloidal chemistry made it possible to synthesize various kinds of ultrathin colloidal nanoplatelets, including wurtzite- and zinc blende-type CdSe, rock salt PbS, black phosphorus-like SnX (X = S or Se), hexagonal copper sulfides, selenides, and even transition metal dichalcogenides like MoS2. By altering experimental conditions and applying capping ligands with specific functional groups, it is possible to accurately tune the dimensionality, geometry, and consequently the optical properties of these colloidal metal chalcogenide crystals. Here, we review recent progress in the syntheses of two-dimensional colloidal metal chalcogenides (CMCs) and property characterizations based on optical spectroscopy or device-related measurements. The discoveries shine a light on their huge prospect for applications in areas such as photovoltaics, optoelectronics, and spintronics. In specific, the formation mechanisms of two-dimensional CMCs are discussed. The growth of colloidal nanocrystals into a two-dimensional shape is found to require either an intrinsic structural asymmetry or the assist of coexisted ligand molecules, which act as lamellar double-layer templates or "facet" the crystals via selective adsorption. By performing optical characterizations and especially ultrafast spectroscopic measurements on these two-dimensional CMCs, their unique electronic and excitonic features are revealed. A strong dependence of optical transition energies linked to both interband and inter-subband processes on the crystal geometry can be verified, highlighting a tremendous confinement effect in such nanocrystals. With the self-assembly of two-dimensional nanocrystals or coupling of different phases by growing heterostructures, unconventional optical performances such as charge transfer state generation or efficient Förster resonance energy transfer are discovered. The growth of large-scale individualized PbS and SnS nanosheets can be realized by facile hot injection techniques, which gives the opportunity to investigate the charge carrier behavior within a single nanocrystal. According to the results of the device-based measurements on these individualized crystals, structure asymmetry-induced anisotropic electrical responses and Rashba effects caused by a splitting of spin-resolved bands in the momentum space due to strong spin-orbit-coupling are demonstrated. It is foreseen that such geometry-controlled, large-scale two-dimensional CMCs can be the ideal materials used for designing high-efficiency photonics and electronics.

8.
Biosens Bioelectron ; 192: 113516, 2021 Nov 15.
Article in English | MEDLINE | ID: mdl-34330036

ABSTRACT

Many rapid antimicrobial susceptibility testing (AST) methods have been proposed to contain clinical antimicrobial resistance (AMR) and preserve the effectiveness of remaining antimicrobials. However, far fewer methods have been proposed to test AMR in resource-limited conditions, such as for frequent safety screenings of water/food/public facilities, urgent surveys of massive samples during a pandemic, or AMR tests in low-income countries. Rapid AST methods realized thus far have a variety of drawbacks when used for such surveys, e.g., high cost and the requirement of expensive instruments such as microscopy. A more reasonable strategy would be to screen samples via onsite testing first, and then send any sample suspected to contain AMR bacteria for advanced testing. Accordingly, a cost-efficient AST is demanded, which can rapidly process a large number of samples without using expensive equipment. To this end, current work demonstrates a novel "barcode" cell sensor based on an adaptive linear filter array as a fully automatic and microscope-free method for counting very small volumes of cells (~1.00 × 104 cells without pre-incubation), wherein suspended cells concentrate into microbars with length proportional to the number of cells. We combined this sensor with an on-chip culture approach we had demonstrated for rapid and automated drug exposure and realized a low-cost and resource-independent platform for portable AST, from which results can be obtained simply through a cell phone. This method has a much shorter turnaround time (2-3 h) than that of standard methods (16-24 h). Thanks to its microscopy-free analysis, affordability, portability, high throughput, and user-friendliness, our "barcode" AST system has the potential to fulfill the various demands of AST when advanced facilities are not available, making it a promising new tool in the fight against AMR.


Subject(s)
Anti-Infective Agents , Biosensing Techniques , Anti-Bacterial Agents/pharmacology , Microbial Sensitivity Tests , Microfluidics
9.
Dementia (London) ; 20(3): 1124-1143, 2021 Apr.
Article in English | MEDLINE | ID: mdl-32380856

ABSTRACT

The use of touchscreen tablets, such as the iPad, offers potential to support the person with dementia staying in a care setting, ranging from a long-term care home to an adult day programme. Although electronic devices are used among people with dementia, a comprehensive review of studies focusing on their impact and how they may be used effectively in care settings is lacking. We conducted a scoping review to summarize existing knowledge about the impact of touchscreen tablets in supporting social connections and reducing responsive behaviours of people with dementia in care settings. Our research team consists of patient partners and family partners, physicians, nurses, a medical student and an academic professor. A total of 17 articles were included in the review. Our analysis identified three ways in which touchscreen tablets support dementia care: (1) increased the person's engagement, (2) decreased responsive behaviours and (3) positive effect on enjoyment/quality of life for people with dementia. Lessons learned and barriers to the use of touchscreen tablets in the care of people with dementia are described. Overall, only a few studies delineated strategies that helped to overcome barriers to technology adoption in care settings. Knowledge translation studies are needed to identify effective processes and practical tips to overcome barriers and realize the potential of assistive technology in dementia care.


Subject(s)
Dementia , Self-Help Devices , Aged , Humans , Long-Term Care , Mobile Applications , Quality of Life
10.
J Rehabil Assist Technol Eng ; 7: 2055668320960385, 2020.
Article in English | MEDLINE | ID: mdl-33282336

ABSTRACT

INTRODUCTION: People with dementia may refuse care because they feel overwhelmed by an unfamiliar environment. Everyday technology such as tablets have the potential to support person-centred dementia care in hospitals. AIMS: We aimed to identify barriers and enabling factors in order to develop a toolkit to support the use of tablets in engaging individual and group activities, especially to play family videos, for hospitalized older people with dementia. METHODS: A participatory action research approach was employed. We facilitated staff focus groups and conducted interviews with stakeholders. A toolkit was developed based on participants' perspectives on how to support successful adoption. RESULTS: Our analysis identified two enabling factors: users' engagement in developing a toolkit for support and adapting implementation to meet local needs. Barriers included staff and family inexperience, mechanical instability of hardware, issues around privacy and data access, technology use and personalization of messages. The toolkit includes short videos, a brochure for family caregivers, and a pocket card for staff.Discussion and implications: Staff, family and patients start with varying levels of experience with the use of tablets, making education and support vitally important to implementation. Health organizations should involve staff, patients, and families to find practical solutions.

11.
BMJ Open ; 9(11): e031653, 2019 11 19.
Article in English | MEDLINE | ID: mdl-31748304

ABSTRACT

INTRODUCTION: The disabilities associated with dementia make the adjustment to staying in a care setting stressful. Separation from family can exacerbate the effects of stress. The use of touch screen tablets such as an iPad may offer potential to support the person with dementia staying in a care setting. Although electronic devices are used among people with dementia for a variety of purposes, a comprehensive review of studies focusing on their impact in care settings for social connection and patient/resident behaviour is lacking. This scoping review will focus on the use of touch screen tablets to support social connections and reducing responsive behaviours of people with dementia while in a care setting, such as a hospital ward. METHODS AND ANALYSIS: This scoping review will follow Joanna Briggs Institute scoping review methodology. The review team consists of two patient partners and three family partners, a nurse researcher, a research assistant and an academic professor. All authors including patient and family partners were involved in preparing this scoping review protocol. In the scoping review, we will search the following databases: MEDLINE, AgeLine, Cochrane, CINAHL, PsycINFO and IEEE. Google and Google Scholar will be used to search for additional literature. A hand search will be conducted using the reference lists of included studies to identify additional relevant articles. Included studies must report on the impact of using a touch screen technology intervention that involves older adults with dementia in care settings, published in English since 2009. ETHICS AND DISSEMINATION: This review study does not require ethics approval. By examining the current state of using touch screen tablets to support older people with dementia in care settings, this scoping review can offer useful insight into users' needs (eg, patients' and care providers' needs) and inform future research and practice. We will share the scoping review results through conference presentations and an open access publication in a peer-reviewed journal.


Subject(s)
Computers, Handheld , Dementia , Hospitalization , Problem Behavior , Research Design , Review Literature as Topic , Social Support , Dementia/therapy , Humans
12.
Mol Biol Cell ; 29(3): 241-246, 2018 02 01.
Article in English | MEDLINE | ID: mdl-29382806

ABSTRACT

An intimate link between centrosome function and neurogenesis is revealed by the identification of many genes with centrosome-associated functions that are mutated in microcephaly disorders. Consistent with the major role of the centrosome in mitosis, mutations in these centrosome-related microcephaly (CRM) genes are thought to affect neurogenesis by depleting the pool of neural progenitor cells, primarily through apoptosis as a consequence of mitotic failure or premature differentiation as a consequence of cell cycle delay and randomization of spindle orientation. However, as suggested by the wide range of microcephaly phenotypes and the multifunctional nature of many CRM proteins, this picture of CRM gene function is incomplete. Here, we explore several examples of CRM genes pointing to additional functions that contribute to microcephaly, including regulation of cell cycle signaling, actin cytoskeleton, and Hippo pathway proteins, as well as functions in postmitotic neurons and glia. As these examples are likely just the tip of the iceberg, further exploration of the roles of microcephaly-related genes are certain to reveal additional unforeseen functions important for neurodevelopment.


Subject(s)
Centrosome/metabolism , Microcephaly/genetics , Microcephaly/metabolism , Actins , Animals , Apoptosis , Cell Cycle/genetics , Cell Differentiation , Centrosome/physiology , Cytoskeleton , Humans , Mitosis , Mutation , Neural Stem Cells/metabolism , Neurogenesis/genetics , Neurons/metabolism , Signal Transduction , Spindle Apparatus/metabolism
13.
G3 (Bethesda) ; 6(7): 1947-57, 2016 07 07.
Article in English | MEDLINE | ID: mdl-27172205

ABSTRACT

The septin family of hetero-oligomeric complex-forming proteins can be divided into subgroups, and subgroup members are interchangeable at specific positions in the septin complex. Drosophila melanogaster has five septin genes, including the two SEPT6 subgroup members Sep2 and Sep5 We previously found that Sep2 has a unique function in oogenesis, which is not performed by Sep5 Here, we find that Sep2 is uniquely required for follicle cell encapsulation of female germline cysts, and that Sep2 and Sep5 are redundant for follicle cell proliferation. The five D. melanogaster septins localize similarly in oogenesis, including as rings flanking the germline ring canals. Pnut fails to localize in Sep5; Sep2 double mutant follicle cells, indicating that septin complexes fail to form in the absence of both Sep2 and Sep5. We also find that mutations in septins enhance the mutant phenotype of bazooka, a key component in the establishment of cell polarity, suggesting a link between septin function and cell polarity. Overall, this work suggests that Sep5 has undergone partial loss of ancestral protein function, and demonstrates redundant and unique functions of septins.


Subject(s)
Drosophila Proteins/genetics , Drosophila melanogaster/genetics , Oogenesis/genetics , Ovarian Follicle/metabolism , Septins/genetics , Animals , Cell Polarity/genetics , Drosophila Proteins/metabolism , Drosophila melanogaster/growth & development , Drosophila melanogaster/metabolism , Evolution, Molecular , Female , Gene Expression Regulation, Developmental , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Microfilament Proteins/genetics , Microfilament Proteins/metabolism , Mutation , Ovarian Follicle/growth & development , Septins/metabolism
14.
Am J Physiol Regul Integr Comp Physiol ; 309(5): R613-22, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26180184

ABSTRACT

Prenatal alcohol exposure (PAE) programs the fetal hypothalamic-pituitary-adrenal (HPA) axis, resulting in HPA dysregulation and hyperresponsiveness to stressors in adulthood. Molecular mechanisms mediating these alterations are not fully understood. Disturbances in one-carbon metabolism, a source of methyl donors for epigenetic processes, contributes to alcoholic liver disease. We assessed whether PAE affects one-carbon metabolism (including Mtr, Mat2a, Mthfr, and Cbs mRNA) and programming of HPA function genes (Nr3c1, Nr3c2, and Slc6a4) in offspring from ethanol-fed (E), pair-fed (PF), and ad libitum-fed control (C) dams. At gestation day 21, plasma total homocysteine and methionine concentrations were higher in E compared with C dams, and E fetuses had higher plasma methionine concentrations and lower whole brain Mtr and Mat2a mRNA compared with C fetuses. In adulthood (55 days), hippocampal Mtr and Cbs mRNA was lower in E compared with C males, whereas Mtr, Mat2a, Mthfr, and Cbs mRNA were higher in E compared with C females. We found lower Nr3c1 mRNA and lower nerve growth factor inducible protein A (NGFI-A) protein in the hippocampus of E compared with PF females, whereas hippocampal Slc6a4 mRNA was higher in E than C males. By contrast, hypothalamic Slc6a4 mRNA was lower in E males and females compared with C offspring. This was accompanied by higher hypothalamic Slc6a4 mean promoter methylation in E compared with PF females. These findings demonstrate that PAE is associated with alterations in one-carbon metabolism and has long-term and region-specific effects on gene expression in the brain. These findings advance our understanding of mechanisms of HPA dysregulation associated with PAE.


Subject(s)
Alcohol Drinking/adverse effects , Ethanol/toxicity , Hippocampus/drug effects , Hypothalamus/drug effects , Prenatal Exposure Delayed Effects , Receptors, Glucocorticoid/metabolism , Serotonin Plasma Membrane Transport Proteins/metabolism , Age Factors , Animals , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , DNA Methylation/drug effects , Early Growth Response Protein 1/genetics , Early Growth Response Protein 1/metabolism , Female , Gene Expression Regulation, Developmental , Gene Expression Regulation, Enzymologic , Gestational Age , Hippocampus/growth & development , Hippocampus/metabolism , Hypothalamus/growth & development , Hypothalamus/metabolism , Male , Maternal Exposure , Pregnancy , RNA, Messenger/metabolism , Rats, Sprague-Dawley , Receptors, Glucocorticoid/genetics , Sex Factors
15.
Int J Evol Biol ; 2013: 693085, 2013.
Article in English | MEDLINE | ID: mdl-23841016

ABSTRACT

Retrogenes form a class of gene duplicate lacking the regulatory sequences found outside of the mRNA-coding regions of the parent gene. It is not clear how a retrogene's lack of parental regulatory sequences affects the evolution of the gene pair. To explore the evolution of parent genes and retrogenes, we investigated three such gene pairs in the family Drosophilidae; in Drosophila melanogaster, these gene pairs are CG8331 and CG4960, CG17734 and CG11825, and Sep2 and Sep5. We investigated the embryonic expression patterns of these gene pairs across multiple Drosophila species. Expression patterns of the parent genes and their single copy orthologs are relatively conserved across species, whether or not a species has a retrogene copy, although there is some variation in CG8331 and CG17734. In contrast, expression patterns of the retrogene orthologs have diversified. We used the genome sequences of 20 Drosophila species to investigate coding sequence evolution. The coding sequences of the three gene pairs appear to be evolving predominantly under negative selection; however, the parent genes and retrogenes show some distinct differences in amino acid sequence. Therefore, in general, retrogene expression patterns and coding sequences are distinct compared to their parents and, in some cases, retrogene expression patterns diversify.

16.
Genome ; 56(12): 753-8, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24433211

ABSTRACT

Septins are cytoskeletal proteins that form hetero-oligomeric complexes and function in many biological processes, including cytokinesis. Drosophila melanogaster has five septin genes. Sep5, which is the most recently evolved septin gene in Drosophila, is a retrogene copy of Sep2. Sep5 mutants appear wild type, whereas Sep2 mutant females are semisterile. Their ovaries have egg chambers containing abnormal numbers of nurse cells. The egg chamber phenotype is rescued to wild type by expressing a Sep2 cDNA, but it is only partially rescued by expressing a Sep5 cDNA, showing that these paralogs have diverged in function at the protein level. Sep2 Sep5 double mutants have an early pupal lethal phenotype and lack imaginal discs, suggesting that these genes have redundant functions during imaginal cell proliferation.


Subject(s)
Drosophila Proteins/physiology , Drosophila melanogaster/genetics , Genes, Insect , Imaginal Discs/cytology , Oogenesis , Septins/genetics , Animals , Animals, Genetically Modified , Cell Proliferation , Drosophila Proteins/genetics , Drosophila melanogaster/physiology , Female , Mutation , Phenotype , Septins/physiology
17.
Br J Psychiatry ; 192(6): 424-8, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18515891

ABSTRACT

BACKGROUND: Obesity and metabolic syndrome are significant problems for patients taking antipsychotic drugs. Evidence is emerging of genetic risk factors. AIMS: To investigate the influence of two candidate genes, smoking and drug treatment on obesity and metabolic syndrome in patients with schizophrenia. METHOD: Patients (n=134) were assessed for measures of obesity, other factors contributing to metabolic syndrome, and two genetic polymorphisms (5-HT(2C) receptor -759C/T and leptin -2548A/G). RESULTS: Neither genotype nor smoking was significantly associated with measures of obesity. However, both leptin genotype and smoking were significantly associated with metabolic syndrome. Significant interaction occurred between the genetic polymorphisms for effects on obesity, whereby a genotype combination increased risk. Drug treatment showed significant effects on measures of obesity and triglyceride concentrations; risperidone was associated with lower values than olanzapine or clozapine. CONCLUSIONS: The findings suggest interacting genetic risk factors and smoking influence development of metabolic syndrome in patients on antipsychotic drugs.


Subject(s)
Antipsychotic Agents/adverse effects , Leptin/genetics , Metabolic Syndrome/etiology , Receptor, Serotonin, 5-HT2C/genetics , Schizophrenia/drug therapy , Smoking/adverse effects , Adult , Alleles , Body Mass Index , Cross-Sectional Studies , Female , Genetic Variation , Genotype , Humans , Male , Metabolic Syndrome/epidemiology , Obesity/epidemiology , Obesity/etiology , Polymorphism, Genetic , Promoter Regions, Genetic , Risk Factors , Schizophrenia/complications , Smoking/epidemiology , Time Factors
18.
Mol Cell Neurosci ; 31(3): 446-62, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16343930

ABSTRACT

Both 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNP) isoforms are abundantly expressed in myelinating cells. CNP2 differs from CNP1 by a 20 amino acid N-terminal extension and is also expressed at much lower levels in non-myelinating tissues. The functional role of CNP2, apart from CNP1, and the significance for CNP2 expression in non-myelinating tissues are unknown. Here, we demonstrate that CNP2 is translocated to mitochondria by virtue of a mitochondrial targeting signal at the N-terminus. PKC-mediated phosphorylation of the targeting signal inhibits CNP2 translocation to mitochondria, thus retaining it in the cytoplasm. CNP2 is imported into mitochondria and the targeting signal cleaved, yielding a mature, truncated form similar in size to CNP1. CNP2 is entirely processed in adult liver and embryonic brain, indicating that it is localized specifically to mitochondria in non-myelinating cells. Our results point to a broader biological role for CNP2 in mitochondria that is likely to be different from its specific role in the cytoplasm, along with CNP1, during myelination.


Subject(s)
Brain/enzymology , Mitochondria/enzymology , Neuroglia/enzymology , Neurons/enzymology , Phosphoric Diester Hydrolases/metabolism , Protein Kinase C/metabolism , 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase , Animals , Brain/embryology , Brain/ultrastructure , Cell Respiration/physiology , Cyclic AMP-Dependent Protein Kinases/metabolism , Energy Metabolism/physiology , Green Fluorescent Proteins , HeLa Cells , Hepatocytes/enzymology , Hepatocytes/ultrastructure , Humans , Immunohistochemistry , Liver/enzymology , Liver/ultrastructure , Microscopy, Electron, Transmission , Mitochondria/ultrastructure , Neuroglia/ultrastructure , Neurons/ultrastructure , Phosphoric Diester Hydrolases/genetics , Phosphorylation , Protein Kinase C/chemistry , Protein Structure, Tertiary/physiology , Protein Transport/physiology , Rats , Subcellular Fractions , Transfection
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