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1.
Anaesthesist ; 69(12): 890-908, 2020 12.
Article in German | MEDLINE | ID: mdl-33048223

ABSTRACT

Somewhere in the USA, shortly before Christmas, tipsy Charlie Cratchit intends to cross a street but is hit by an oncoming city bus und suffers severe trauma: serial rib fracture, femoral fracture, fibula fracture, splenic, pancreatic and bowel ruptures. He is operated on in a maximum care hospital and then transferred to the critical care unit. From then on, an anonymous, very experienced physician continuously takes care of him. Four nights before Christmas, the ghost of the famous British physiologist Ernest Henry Starling appears at the patient's bed. The ghost involves the anonymous physician in a dialogue and is very interested in the inserted Swan-Ganz catheter, then he disappears. He repeats his visits the next 3 nights. On the first occasion he is displeased with Cratchit's low haematocrit, the second time he dislikes the mechanical ventilator settings, and on his final visit he is concerned with Cratchit's clinical nutrition. At first, the anonymous physician is indignant with the ghost's criticism and indoctrinations, but then recognizes that ultimately they are the key to Cratchit's convalescence and acts accordingly. Successfully! Following the ghost's proposals, he changes the ventilator settings, transfuses 3 units of packed red blood cells, and starts clinical nutrition. Shortly thereafter, Cratchit's trachea is extubated, and on New Year's Day he is ready to be discharged from the critical care unit. In this essay, Robert Bartlett transposed Charles Dickens' "Christmas Carol" into the world of critical care. Its intention is to encourage the intensivist to scrutinize common therapeutic measures, such as mechanical ventilation, haemodynamic interventions and transfusion of blood products. Background information and comments on the addressed problems of modern intensive care are provided subsequent to the essay.


Subject(s)
Anemia , Home Care Services , Asphyxia , Critical Care , Humans , Male
2.
Dysphagia ; 33(4): 457-467, 2018 08.
Article in English | MEDLINE | ID: mdl-29353401

ABSTRACT

Self-perception of disease is increasingly recognized as a determinant of health. The Eating Assessment Tool-10 (EAT-10) is a functional health status questionnaire that measures the symptomatic severity of dysphagia from the patient's perspective. The objective of this work was to identify factors (demographics, clinical variables, swallowing physiology, health-related quality of life) associated with longitudinal change in EAT-10 scores in outpatients with oropharyngeal dysphagia at a multi-disciplinary, tertiary care clinic. All patients with swallowing concerns that were included in the UW Madison Voice and Swallowing Outcomes database from 12/2012 to 04/2015 were invited to complete EAT-10 and a general health-related quality of life survey (SF-12v2) at their initial evaluation and six months later. Forty-two patients were included in analysis (n = 42). Weaning from a gastrostomy tube was significantly associated with EAT-10 improvement. Approximately 70% of the sample had mild dysphagia, and floor effects were observed for all EAT-10 items in this sample subset. Mean SF-12v2 Physical Component Summary score was substantially lower than that of the general population. Significant, weak-moderate correlations were found between EAT-10 and SF-12v2 scores for all comparisons except for Physical Health Composite at six months (rs = = 0.24 to - 0.43). Weaning from a feeding tube appears to meaningfully improve self-perceived symptoms of dysphagia. Given the floor effects observed, validity of EAT-10 for patients with mild dysphagia should be examined. Future research should address contributors to self-perceived symptom change across the range of dysphagia severity.


Subject(s)
Deglutition Disorders/psychology , Quality of Life , Aged , Deglutition/physiology , Female , Humans , Male , Outpatients , Prospective Studies , Self Concept , Tertiary Healthcare
3.
Anaesthesist ; 66(1): 34-44, 2017 Jan.
Article in German | MEDLINE | ID: mdl-27924353

ABSTRACT

Robert Bartlett, emeritus Professor of surgery at the University of Michigan in Ann Arbor, USA, transformed classical works of world literature (Charles Dickens: A Christmas Carol, Lewis Carroll: Alice in Wonderland) into teaching aids for advanced training in intensive care medicine. He recently turned his hand to the well-known work of Ernest Hemingway: the Nobel Prize winning novel The Old Man and the Sea. Subsequent to Robert Bartlett's essay this article provides background information and comments on the current problems in modern intensive care medicine addressed in his essay.


Subject(s)
Critical Care , Literature , Teaching Materials , Evidence-Based Medicine , Humans , Respiratory Distress Syndrome/therapy , Sepsis/therapy
4.
Cytotherapy ; 18(10): 1284-96, 2016 10.
Article in English | MEDLINE | ID: mdl-27637759

ABSTRACT

BACKGROUND: Regenerative medicine holds promise for restoring voice in patients with vocal fold scarring. As experimental treatments approach clinical translation, several considerations remain. Our objective was to evaluate efficacy and biocompatibility of four bone marrow mesenchymal stromal cell (BM-MSC) and tunable hyaluronic acid based hydrogel (HyStem-VF) treatments for vocal fold scar using clinically acceptable materials, a preclinical sample size and a dosing comparison. METHODS: Vocal folds of 84 rabbits were injured and injected with four treatment variations (BM-MSC, HyStem-VF, and BM-MSC in HyStem-VF at two concentrations) 6 weeks later. Efficacy was assessed with rheometry, real-time polymerase chain reaction (RT-PCR) and histology at 2, 4 and 10 weeks following treatment. Lung, liver, kidney, spleen and vocal folds were screened for biocompatibility by a pathologist. RESULTS AND DISCUSSION: Persistent inflammation was identified in all hydrogel-injected groups. The BM-MSC alone treatment appeared to be the most efficacious and safe, providing an early resolution of viscoelasticity, gene expression consistent with desirable extracellular matrix remodeling (less fibronectin, collagen 1α2, collagen 3, procollagen, transforming growth factor [TGF]ß1, alpha smooth muscle actin, interleukin-1ß, interleukin-17ß and tumor necrosis factor [TNF] than injured controls) and minimal inflammation. Human beta actin expression in BM-MSC-treated vocal folds was minimal after 2 weeks, suggesting that paracrine signaling from the BM-MSCs may have facilitated tissue repair.


Subject(s)
Cicatrix/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/physiology , Regeneration/physiology , Vocal Cords/physiology , Vocal Cords/surgery , Wound Healing , Animals , Cells, Cultured , Cicatrix/pathology , Female , Humans , Injections , Rabbits , Transforming Growth Factor beta1/metabolism , Vocal Cords/cytology , Vocal Cords/transplantation , Young Adult
5.
Perfusion ; 29(1): 39-43, 2014 Jan.
Article in English | MEDLINE | ID: mdl-23863490

ABSTRACT

PURPOSE: Legionella is a common cause of community-acquired pneumonia (CAP) and is second only to Pneumococcal pneumonia as a cause of severe CAP that requires treatment in an intensive care unit. We report a case series of patients with severe Legionella pneumonia who developed the acute respiratory distress syndrome (ARDS), failed to improve with mechanical ventilation alone and required extracorporeal life support (ECLS). METHODS: We performed a retrospective study of all patients treated with ECLS at our institution for severe ARDS as a result of Legionella pneumonia from 1994 to 2006. RESULTS: A total of twelve patients with a diagnosis of Legionella pneumonia were treated with veno-venous (VV) ECLS over this time period. Nine of these twelve (75%) were successfully treated and weaned off ECLS and 8 patients (67%) survived to hospital discharge. Two (13%) died of multisystem organ failure, one patient (8%) died from global hypoxic encephalopathy and one (8%) was weaned from ECLS, but ultimately died of liver failure. Renal failure requiring some form of continuous dialysis occurred in seven patients (58%) and the survival for this sub-set of patients was 43%. CONCLUSIONS: Extracorporeal life support for severe ARDS associated with Legionella pneumonia is an effective treatment option when mechanical ventilation fails, especially when introduced early in the course.


Subject(s)
Extracorporeal Membrane Oxygenation/methods , Legionnaires' Disease/therapy , Respiratory Distress Syndrome/microbiology , Respiratory Distress Syndrome/therapy , Acute Disease , Adult , Female , Humans , Male , Middle Aged , Retrospective Studies
6.
Ground Water ; 62(2): 303-309, 2024.
Article in English | MEDLINE | ID: mdl-37317947

ABSTRACT

Solute migration is typically simulated to describe and estimate the fate and transport of contaminants in groundwater. The unit-concentration approach is investigated here as a method to enable solute transport simulations to expand the capabilities of groundwater flow modeling. The unit-concentration method uses a concentration value of one to identify sources of water to be assessed and a concentration of zero for all other water sources. The distribution of concentration thus obtained, unlike particle tracking methods, provides a more intuitive and direct quantification of the contribution of sources reaching various sinks. The unit-concentration approach can be applied readily with existing solute transport software for a range of analyses including source allocation, well capture analysis, and mixing/dilution calculations. This paper presents the theory, method, and example applications of the unit-concentration approach for source quantification.


Subject(s)
Groundwater , Water Pollutants, Chemical , Models, Theoretical , Water Pollutants, Chemical/analysis , Water Movements , Water/analysis
7.
Neuroradiology ; 55(9): 1081-8, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23740097

ABSTRACT

INTRODUCTION: Cervical spine MRI with the neck in extension has been well described over the last 10 years, but its clinical value remains unknown. METHODS: We performed extension imaging in 60 patients in whom the initial neutral study showed borderline cord compression. Images were assessed using a previously validated grading system for cord compression. Multiple linear and area measurements were also obtained. Images were scored blindly and randomly. Inter- and intra-rater variability were determined in a subset of 20 cases. Independent clinical assessment utilised the Ranwat criteria. RESULTS: For most parameters inter/intra-observer variance of kappa/ICC > 0.6 was highly satisfactory. Standard MR was poor at discriminating between patients with and without myelopathy (ROC analysis, area under the curve (AUC), 0.52). This was considerably improved with extension imaging (AUC, 0.60), or by using the change in compression score between neutral and extension studies. Most measurements were not helpful; however, the ratio of cord area/CSF area at the level of maximum compression on extended images was the best discriminator (AUC, 0.71), as well as the presence of T2 change in cord substance (AUC, 0.68). CONCLUSION: This is the first study to demonstrate added clinical value utilising extension MRI. In this cohort of difficult patients, when there was no T2 signal change in the cord, the presence of clinical myelopathy could only be predicted by utilising the data from extension imaging.


Subject(s)
Algorithms , Cervical Vertebrae/pathology , Image Interpretation, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Neck/pathology , Spinal Cord Compression/pathology , Adult , Aged , Aged, 80 and over , Female , Humans , Image Enhancement/methods , Male , Middle Aged , Observer Variation , Reproducibility of Results , Sensitivity and Specificity , Young Adult
8.
Nat Genet ; 15(3): 293-7, 1997 Mar.
Article in English | MEDLINE | ID: mdl-9054945

ABSTRACT

Type 1, or insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease associated with loss of tolerance to several pancreatic islet cell molecules, including insulin, glutamic acid decarboxylase (GAD), ICA69 and the tyrosine phosphatase IA-2 (refs 1-3). Among several predisposing loci, IDDM2 maps to the insulin gene (INS) VNTR (variable number of tandem repeats) minisatellite on chromosome 11p15 (refs 4-9). Allelic variation at this VNTR locus correlates with steady-state levels of INS mRNA in pancreas and transfected rodent cell lines, but it is difficult to reconcile the association of lower INS mRNA levels in the pancreas with class III VNTRs that are dominantly protective from IDDM. We show that during fetal development and childhood, mRNAs for insulin and other islet cell autoantigens (GAD, ICA69, IA-2) are expressed at low levels in the human thymus. Critically, we also detect proinsulin and insulin protein. VNTR alleles correlate with differential INS mRNA expression in the thymus where, in contrast to the pancreas, protective class III VNTRs are associated with higher steady-state levels of INS mRNA expression. This finding provides a plausible explanation for the dominant protective effect of class III VNTRs, and suggests that diabetes susceptibility and resistance associated with IDDM2 may derive from the VNTR influence on INS transcription in the thymus. Higher levels of (pro)insulin in the thymus may promote negative selection (deletion) of insulin-specific T-lymphocytes which play a critical role in the pathogenesis of type-1 diabetes.


Subject(s)
Chromosomes, Human, Pair 11 , Diabetes Mellitus, Type 1/genetics , Gene Expression Regulation, Developmental , Insulin/biosynthesis , Insulin/genetics , Minisatellite Repeats , Thymus Gland/metabolism , Transcription, Genetic , Aging , Alleles , Child , Child, Preschool , Chromosome Mapping , DNA Primers , Disease Susceptibility , Embryonic and Fetal Development , Genetic Variation , Humans , Infant , Infant, Newborn , Organ Specificity , Polymerase Chain Reaction , Proinsulin/biosynthesis , RNA, Messenger/biosynthesis , Thymus Gland/embryology , Thymus Gland/growth & development
9.
Perfusion ; 27(2): 141-5, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22143092

ABSTRACT

Lower extremity ischemia is common when the femoral artery is used for veno-arterial extracorporeal membrane oxygenation (VA ECMO). We describe a new technique to reperfuse the extremity. The ipsilateral posterior tibial artery is exposed via a small incision behind the medial malleolus. The vessel is cannulated in a retrograde fashion and connected to the arterial limb of the ECMO circuit. Thirty-six patients received a posterior tibial reperfusion cannula: average flow was 155.8 ml/min and increased over the initial 24 hours. Fifty-eight percent received the posterior tibial cannula within 6 hours of ECMO initiation and none sustained permanent lower extremity injury. Of the remaining 42%, three required amputation or developed permanent neurologic injury. Overall survival was 41%. Cannulation of the posterior tibial artery is a simple technique to reperfuse the lower extremity during VA ECMO. The cannula should be inserted within 6 hours of ECMO initiation to avoid irreversible ischemic damage.


Subject(s)
Extracorporeal Membrane Oxygenation/methods , Femoral Artery/surgery , Ischemia/prevention & control , Leg/blood supply , Tibia/blood supply , Tibial Arteries/surgery , Adolescent , Adult , Catheterization/methods , Child , Cohort Studies , Extracorporeal Membrane Oxygenation/adverse effects , Humans , Ischemia/etiology , Leg/surgery , Middle Aged , Tibia/surgery , Young Adult
10.
Sci Rep ; 12(1): 9366, 2022 06 07.
Article in English | MEDLINE | ID: mdl-35672326

ABSTRACT

To evaluate regional axonal-related parameters as a function of disease stage in primary open angle glaucoma (POAG) and visual field (VF) sensitivity. Spectral domain optical coherence tomography was used to acquire 20° scans of POAG (n = 117) or healthy control (n = 52) human optic nerve heads (ONHs). Region specific and mean nerve fibre layer (NFL) thicknesses, border NFL and peripapillary NFL, minimum rim width (MRW)/ area (MRA) and prelamina thickness; and volume were compared across POAG disease stages and with visual field sensitivity. Differences identified between early glaucoma (EG), preperimetric glaucoma (PG) and control (C) ONHs included thinner PG prelamina regions than in controls (p < 0.05). Mean border NFL was thinner in EG (p < 0.001) and PG (p = 0.049) compared to control eyes; and EG mean, and inferior and ST, border NFL was thinner than in PG (p < 0.01). Mean, superior and inferior PG peripapillary NFL were thinner than in controls (p < 0.05), and EG ST peripapillary NFL was thinner than in PG (p = 0.023). MRW differences included: PG SN and inferior less than in controls (p < 0.05); thinner EG mean regional, inferior, nasal, and ST MRW versus PG MRW (p < 0.05). Regional border NFL, peripapillary NFL, MRW, MRA, prelamina thickness (except centre, p = 0.127) and prelamina volume (p < 0.05) were significantly associated with VF mean deviation (MD). Novel axon-derived indices hold potential as biomarkers to detect early glaucoma and identify ONHs at risk.


Subject(s)
Glaucoma, Open-Angle , Glaucoma , Biomarkers , Glaucoma/diagnosis , Humans , Intraocular Pressure , Retinal Ganglion Cells , Tomography, Optical Coherence/methods
11.
J Exp Med ; 153(6): 1629-39, 1981 Jun 01.
Article in English | MEDLINE | ID: mdl-6973002

ABSTRACT

An in vitro acute-depletion protocol was used to detect trinitrophenyl (TNP)-specific, allo-major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) within thymocytes of inbred mice. After removal of alloreactivity, the negatively selected cells could be sensitized to become TNP-specific, allo-MHC-restricted cytotoxic T cells. A precursors frequency analysis revealed a three- to ninefold lower frequency of allo-MHC-restricted CTL precursors (CTL-P) as compared to self-MHC-restricted CTL-P. The specificity analysis of clonally distributed allo-MHC-restricted CTL-P excluded cross-reactivity as an explanation of allo-MHC restriction. These results provide direct evidence that thymic T cells are composed of a mixture of self-MHC- and allo-MHC-restricted immunocompetent T cells and that antigen-driven selection of precommitted T cells dictates the H-2-restriction phenotype, i.e., H-2 restriction is a consequence of priming.


Subject(s)
Cytotoxicity, Immunologic , Immunologic Memory , T-Lymphocytes/immunology , Thymus Gland/immunology , Animals , H-2 Antigens , Leukocyte Count , Major Histocompatibility Complex , Mice , Spleen/immunology , Trinitrobenzenes/immunology
12.
J Exp Med ; 153(6): 1517-32, 1981 Jun 01.
Article in English | MEDLINE | ID: mdl-6265587

ABSTRACT

To study whether the thymic major histocompatibility complex (MHC) imposes a constraint on the receptor repertoire of maturating cytotoxic T lymphocyte (CTL) precursors, the restriction phenotypes of virus-specific CTL of MHC-compatible and of MHC-incompatible thymus- and bone marrow-grafted (A X B)F1 chimeric mice were compared. Dependent on the mode of in vitro sensitization, thymocytes or splenocytes of both types of chimeric mice generated Sendai virus-specific, self-MHC-or allo-MHC-restricted CTL. By applying the limiting-dilution technique, the CTL-precursor (CTL-P) frequencies of self-MHC-restricted and allo-MHC-restricted virus-specific T cells as well as of alloreactive T cells were determined. The data obtained revealed that independent of MHC differences between thymus and bone marrow, the frequencies of self-MHC-restricted and allo-MHC-restricted CTL-P were comparable, and in the same older of magnitude as those previously determined in conventionally reared mice. Self-MHC-restricted, virus-specific CTL-P were in a three- to fivefold excess over allo-MHC-restricted CTL-P. A segregation analysis revealed that clonally distinct CTL-P give rise to either self-restricted or allo-MHC-restricted, virus-specific CTL. Both sets were found not only in the spleen, but also in the thymus of chimeric mice, formally demonstrating the intrathymic differentiation pathway of self-MHC as well of allo-MHC-restricted CTL-P. These data reveal no major constraint of the thymic MHC on the capacity of T cells to recognize viral antigens either in the context of self-MHC or of allogeneic MHC products.


Subject(s)
Cytotoxicity, Immunologic , Major Histocompatibility Complex , T-Lymphocytes/immunology , Thymus Gland/immunology , Animals , Bone Marrow/immunology , Cell Differentiation , Clone Cells/immunology , Mice , Mice, Inbred BALB C , Mice, Inbred CBA , Parainfluenza Virus 1, Human/immunology , Radiation Chimera , Spleen/immunology
13.
Am J Transplant ; 10(6): 1365-74, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20553447

ABSTRACT

Donors after cardiac death (DCD) could increase the organ pool. Data supports good long-term renal graft survival. However, DCDs are <10% of deceased donors in the United States, due to delayed graft function, and primary nonfunction. These complications are minimized by extracorporeal support after cardiac death (ECS-DCD). This study assesses immediate and acute renal function from different donor types. DCDs kidneys were recovered by conventional rapid recovery or by ECS, and transplanted into nephrectomized healthy swine. Warm ischemia of 10 and 30 min were evaluated. Swine living donors were controls (LVD). ECS-DCDs were treated with 90 min of perfusion until organ recovery. After procurement, kidneys were cold storage 4-6 h. Renal vascular resistance (RVR), urine output (UO), urine protein concentration (UrPr) and creatinine clearance (CrCl), were collected during 4 h posttransplantation. All grafts functioned with adequate renal blood flow for 4 h. RVR at 4 h posttransplant returned to baseline only in the LVD group (0.36 mmHg/mL/min +/- 0.03). RVR was higher in all DCDs (0.66 mmHg/mL/min +/- 0.13), without differences between them. UO was >50 mL/h in all DCDs, except in DCD-30 (6.8 mL/h +/- 1.7). DCD-30 had lower CrCl (0.9 mL/min +/- 0.2) and higher UrPr >200 mg/dL, compared to other DCDs >10 mL/min and <160 mg/dL, respectively. Normothermic ECS can resuscitate kidneys to transplantable status after 30 min of cardiac arrest/WI.


Subject(s)
Death , Kidney Transplantation/physiology , Animals , Creatinine , Delayed Graft Function/physiopathology , Female , Graft Survival , Heart Arrest/physiopathology , Kidney/physiology , Kidney/physiopathology , Kidney Function Tests , Perfusion , Swine , Tissue Donors , Warm Ischemia
14.
Science ; 235(4796): 1648-50, 1987 Mar 27.
Article in English | MEDLINE | ID: mdl-3029876

ABSTRACT

Myotonic muscular dystrophy (DM) is the most common muscular dystrophy, affecting adults as well as children. It is inherited as an autosomal dominant trait and is characterized by variable expressivity and late age-of-onset. Linkage studies have established the locus on chromosome 19. In order to identify tightly linked probes for diagnosis as well as to define in detail the DM gene region, chromosome 19 libraries were constructed and screened for restriction fragment length polymorphisms tightly linked to DM. A genomic clone, LDR152 (D19S19), was isolated that is tightly linked to DM; recombination fraction = 0.0 (95% confidence limits 0.0-0.03); lod score, 15.4.


Subject(s)
Muscular Dystrophies/diagnosis , Adult , Autoradiography , Child , Chromosome Mapping , Chromosomes, Human, Pair 19 , DNA Restriction Enzymes/metabolism , Genetic Linkage , Humans , Muscular Dystrophies/genetics , Pedigree , Polymorphism, Genetic
15.
Anaesthesia ; 64(3): 320-2, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19302648

ABSTRACT

Following a critical incident on our labour ward, we investigated the forces required to remove different bougies from different tracheal tubes and the effect of lubrication on ease of removal. Two studies were conducted: firstly examining the differences between six different bougies with a standard tracheal tube, and secondly examining the differences between four different tracheal tubes with a standard bougie. The forces varied amongst both the different bougies (p < 0.0001) and the different tracheal tubes (p < 0.0001). Removal was generally easier with lubrication but when corrected for multiple comparisons this did not reach statistical significance.


Subject(s)
Device Removal , Intubation, Intratracheal/instrumentation , Friction , Humans , Lubrication , Manikins , Stress, Mechanical
16.
Transplant Proc ; 51(3): 979-986, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30979491

ABSTRACT

OBJECTIVE: The aim of this study was to evaluate the impact of static cold storage preservation on skeletal muscle metabolism using a rodent model. METHODS: Sixteen male Lewis rats (250 ± 25 g) were distributed into 4 groups, including naive control, warm ischemia for 2 hours, static warm storage for 6 hours, and static cold storage for 6 hours. Energy status, metabolomics profiling, and histopathology of the muscle were analyzed. RESULTS: In the warm ischemia and static warm storage groups, glycolytic pathway metabolites decreased, but the Krebs cycle metabolite of succinate and the purine degradation product of hypoxanthine accumulated. Increased succinate and hypoxanthine levels were associated with increased injury severity scores. During static cold storage, the glycolytic pathway activity and the energy status were preserved. Succinate and hypoxanthine levels showed no significant difference from the naive group. CONCLUSION: Warm ischemia results in reduced glycolysis and Krebs cycle metabolites. Static cold storage preserves the glycolytic pathway and represents a favorable contribution to cellular energy demand. Succinate and hypoxanthine might be used as novel potential biomarkers for the assessment of viability and injury severity.


Subject(s)
Cryopreservation/methods , Metabolomics/methods , Muscle, Skeletal/metabolism , Organ Preservation/methods , Animals , Male , Models, Animal , Muscle, Skeletal/cytology , Rats , Rats, Inbred Lew , Warm Ischemia/methods
17.
Talanta ; 205: 120077, 2019 Dec 01.
Article in English | MEDLINE | ID: mdl-31450395

ABSTRACT

Implantable medical devices are an integral part of primary/critical care. However, these devices carry a high risk for blood clots, caused by platelet aggregation on a foreign body surface. This study focuses on the development of a simplified approach to create nitric oxide (NO) releasing intravascular electrochemical oxygen (O2) sensors with increased biocompatibility and analytical accuracy. The implantable sensors are prepared by embedding S-nitroso-N-acetylpenacillamine (SNAP) as the NO donor molecule in the walls of the catheter type sensors. The SNAP-impregnated catheters were prepared by swelling silicone rubber tubing in a tetrahydrofuran solution containing SNAP. Control and SNAP-impregnated catheters were used to fabricate the Clark-style amperometric PO2 sensors. The SNAP-impregnated sensors release NO under physiological conditions for 18 d as measured by chemiluminescence. The analytical response of the SNAP-impregnated sensors was evaluated in vitro and in vivo. Rabbit and swine models (with sensors placed in both veins and arteries) were used to evaluate the effects on thrombus formation and analytical in vivo PO2 sensing performance. The SNAP-impregnated PO2 sensors were found to more accurately measure PO2 levels in blood continuously (over 7 and 20 h animal experiments) with significantly reduced thrombus formation (as compared to controls) on their surfaces.


Subject(s)
Electrochemical Techniques/instrumentation , Nitric Oxide Donors/chemistry , Oxygen/blood , S-Nitroso-N-Acetylpenicillamine/chemistry , Vascular Access Devices , Animals , Electrochemical Techniques/methods , Equipment Design , Femoral Artery , Luminescent Measurements , Nitric Oxide/pharmacokinetics , Rabbits , Silicones , Swine
18.
Proc Biol Sci ; 275(1643): 1685-93, 2008 Jul 22.
Article in English | MEDLINE | ID: mdl-18445557

ABSTRACT

We tested whether the sex pheromones that stimulate courtship clasping in male roughskin newts do so, at least in part, by amplifying the somatosensory signals that directly trigger the motor pattern associated with clasping and, if so, whether that amplification is dependent on endogenous vasotocin (VT). Female olfactory stimuli increased the number of action potentials recorded in the medulla of males in response to tactile stimulation of the cloaca, which triggers the clasp motor reflex, as well as to tactile stimulation of the snout and hindlimb. That enhancement was blocked by exposing the medulla to a V1a receptor antagonist before pheromone exposure. However, the antagonist did not affect medullary responses to tactile stimuli in the absence of pheromone exposure, suggesting that pheromones amplify somatosensory signals by inducing endogenous VT release. The ability of VT to couple sensory systems together in response to social stimulation could allow this peptide to induce variable behavioural outcomes, depending on the immediate context of the social interaction and thus on the nature of the associated stimuli that are amplified. If widespread in vertebrates, this mechanism could account for some of the behavioural variability associated with this and related peptides both within and across species.


Subject(s)
Medulla Oblongata/metabolism , Salamandridae/physiology , Sex Attractants/pharmacology , Vasotocin/physiology , Action Potentials/drug effects , Animals , Antidiuretic Hormone Receptor Antagonists , Cloaca/physiology , Electrophysiology , Female , Male , Medulla Oblongata/cytology , Medulla Oblongata/physiology , Neurons, Afferent/drug effects , Neurons, Afferent/physiology , Physical Stimulation , Receptors, Vasopressin , Sex Attractants/physiology , Sexual Behavior, Animal , Stimulation, Chemical
19.
J Chem Phys ; 129(6): 064103, 2008 Aug 14.
Article in English | MEDLINE | ID: mdl-18715047

ABSTRACT

Singlet and triplet electronic excitation energies have been calculated for Ne, CH(2), C(2), N(2), and H(2)O using the Monte Carlo configuration interaction (CI) method. We find that excitation energies can be predicted to within a few tens of meV of full CI (FCI) results using expansions consisting of only a few thousand configuration state functions as compared to the O(10(8)) configurations occurring in the corresponding FCI expansions. The method provides a consistently accurate and balanced description of electronic excitations with accuracy for small molecular systems comparable to the equation-of-motion coupled cluster method with full triples.

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