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Moss PIEZO homologs have a conserved structure, are ubiquitously expressed, and do not affect general vacuole function. PLANT SIGNALING & BEHAVIOR 2022; 17:2015893. [PMID: 34951344 PMCID: PMC8920221 DOI: 10.1080/15592324.2021.2015893] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/04/2021] [Accepted: 12/04/2021] [Indexed: 06/14/2023]
Abstract
The PIEZO protein family was first described in animals where these mechanosensitive calcium channels perform numerous essential functions, including the perception of light touch, shear, and compressive forces. PIEZO homologs are present in most eukaryotic lineages and recently we reported that two PIEZO homologs from moss Physcomitrium patens localize to the vacuolar membrane and modulate its morphology in tip-growing caulonemal cells. Here we show that predicted structures of both PpPIEZO1 and PpPIEZO2 are very similar to that of mouse Piezo2. Furthermore, we show that both moss PIEZO genes are ubiquitously expressed in moss vegetative tissues and that they are not required for normal vacuolar pH or intracellular osmotic potential. These results suggest that moss PIEZO proteins are widely expressed mechanosensory calcium channels that serve a signaling rather than maintenance role in vacuoles.
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Unbiased proteomic and forward genetic screens reveal that mechanosensitive ion channel MSL10 functions at ER-plasma membrane contact sites in Arabidopsis thaliana. eLife 2022; 11:80501. [PMID: 36205399 PMCID: PMC9625087 DOI: 10.7554/elife.80501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022] Open
Abstract
Mechanosensitive (MS) ion channels are an evolutionarily conserved way for cells to sense mechanical forces and transduce them into ionic signals. The channel properties of Arabidopsis thaliana MscS-Like (MSL)10 have been well studied, but how MSL10 signals remains largely unknown. To uncover signaling partners of MSL10, we employed a proteomic screen and a forward genetic screen; both unexpectedly implicated endoplasmic reticulum–plasma membrane contact sites (EPCSs) in MSL10 function. The proteomic screen revealed that MSL10 associates with multiple proteins associated with EPCSs. Of these, only VAMP-associated proteins (VAP)27-1 and VAP27-3 interacted directly with MSL10. The forward genetic screen, for suppressors of a gain-of-function MSL10 allele (msl10-3G, MSL10S640L), identified mutations in the synaptotagmin (SYT)5 and SYT7 genes. We also found that EPCSs were expanded in leaves of msl10-3G plants compared to the wild type. Taken together, these results indicate that MSL10 associates and functions with EPCS proteins, providing a new cell-level framework for understanding MSL10 signaling. In addition, placing a mechanosensory protein at EPCSs provides new insight into the function and regulation of this type of subcellular compartment.
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Plant PIEZO homologs modulate vacuole morphology during tip growth. Science 2021; 373:586-590. [PMID: 34326243 DOI: 10.1126/science.abe6310] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/24/2021] [Accepted: 06/16/2021] [Indexed: 12/11/2022]
Abstract
In animals, PIEZOs are plasma membrane-localized cation channels involved in diverse mechanosensory processes. We investigated PIEZO function in tip-growing cells in the moss Physcomitrium patens and the flowering plant Arabidopsis thaliana PpPIEZO1 and PpPIEZO2 redundantly contribute to the normal growth, size, and cytoplasmic calcium oscillations of caulonemal cells. Both PpPIEZO1 and PpPIEZO2 localized to vacuolar membranes. Loss-of-function, gain-of-function, and overexpression mutants revealed that moss PIEZO homologs promote increased complexity of vacuolar membranes through tubulation, internalization, and/or fission. Arabidopsis PIEZO1 also localized to the tonoplast and is required for vacuole tubulation in the tips of pollen tubes. We propose that in plant cells the tonoplast has more freedom of movement than the plasma membrane, making it a more effective location for mechanosensory proteins.
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Towards blood flow in the virtual human: efficient self-coupling of HemeLB. Interface Focus 2021; 11:20190119. [PMID: 33335704 PMCID: PMC7739917 DOI: 10.1098/rsfs.2019.0119] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/23/2020] [Indexed: 11/12/2022] Open
Abstract
Many scientific and medical researchers are working towards the creation of a virtual human—a personalized digital copy of an individual—that will assist in a patient’s diagnosis, treatment and recovery. The complex nature of living systems means that the development of this remains a major challenge. We describe progress in enabling the HemeLB lattice Boltzmann code to simulate 3D macroscopic blood flow on a full human scale. Significant developments in memory management and load balancing allow near linear scaling performance of the code on hundreds of thousands of computer cores. Integral to the construction of a virtual human, we also outline the implementation of a self-coupling strategy for HemeLB. This allows simultaneous simulation of arterial and venous vascular trees based on human-specific geometries.
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Heritable Phytohormone Profiles of Poplar Genotypes Vary in Resistance to a Galling Aphid. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:654-672. [PMID: 30520677 DOI: 10.1094/mpmi-11-18-0301-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Insect galls are highly specialized structures arising from atypical development of plant tissue induced by insects. Galls provide the insect enhanced nutrition and protection against natural enemies and environmental stresses. Galls are essentially plant organs formed by an intimate biochemical interaction between the gall-inducing insect and its host plant. Because galls are plant organs, their development is likely to be governed by phytohormones involved in normal organogenesis. We characterized concentrations of both growth and defensive phytohormones in ungalled control leaves and galls induced by the aphid Pemphigus betae on narrowleaf cottonwood Populus angustifolia that differ genotypically in resistance to this insect. We found that susceptible trees differed from resistant trees in constitutive concentrations of both growth and defense phytohormones. Susceptible trees were characterized by significantly higher constitutive cytokinin concentrations in leaves, significantly greater ability of aphids to elicit cytokinin increases, and significantly lower constitutive defense phytohormone concentrations than observed in resistant trees. Phytohormone concentrations in both constitutive and induced responses in galled leaves exhibited high broad-sense heritability that, respectively, ranged from 0.39 to 0.93 and from 0.28 to 0.66, suggesting that selection can act upon these traits and that they might vary across the landscape. Increased cytokinin concentrations may facilitate forming strong photosynthate sinks in the galls, a requirement for galling insect success. By characterizing for the first time the changes in 15 phytohormones belonging to five different classes, this study offers a better overview of the signaling alteration occurring in galls that has likely been important for their ecology and evolution. Copyright © 2019 The Author(s). This is an open-access article distributed under the CC BY-NC-ND 4.0 International license .
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The heterogeneous multiscale method applied to inelastic polymer mechanics. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20180150. [PMID: 30967034 PMCID: PMC6388009 DOI: 10.1098/rsta.2018.0150] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/09/2018] [Indexed: 05/18/2023]
Abstract
Mechanisms emerging across multiple scales are ubiquitous in physics and methods designed to investigate them are becoming essential. The heterogeneous multiscale method (HMM) is one of these, concurrently simulating the different scales while keeping them separate. Owing to the significant computational expense, developments of HMM remain mostly theoretical and applications to physical problems are scarce. However, HMM is highly scalable and is well suited for high performance computing. With the wide availability of multi-petaflop infrastructures, HMM applications are becoming practical. Rare applications to mechanics of materials at low loading amplitudes exist, but are generally confined to the elastic regime. Beyond that, where history-dependent, irreversible or nonlinear mechanisms occur, not only computational cost but also data management issues arise. The micro-scale description loses generality, developing a specific microstructure based on the deformation history, which implies inter alia that as many microscopic models as discrete locations in the macroscopic description must be simulated and stored. Here, we present a detailed description of the application of HMM to inelastic mechanics of materials, with emphasis on the efficiency and accuracy of the scale-bridging methodology. The method is well suited to the estimation of macroscopic properties of polymers (and derived nanocomposites) starting from knowledge of their atomistic chemical structure. Through application of the resulting workflow to polymer fracture mechanics, we demonstrate deviation in the predicted fracture toughness relative to a single-scale molecular dynamics approach, thus illustrating the need for such concurrent multiscale methods in the predictive estimation of macroscopic properties. This article is part of the theme issue 'Multiscale modelling, simulation and computing: from the desktop to the exascale'.
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Genetic and physical interactions between the organellar mechanosensitive ion channel homologs MSL1, MSL2, and MSL3 reveal a role for inter-organellar communication in plant development. PLANT DIRECT 2019; 3:e00124. [PMID: 31245767 PMCID: PMC6508831 DOI: 10.1002/pld3.124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/24/2019] [Accepted: 02/11/2019] [Indexed: 05/31/2023]
Abstract
Plant development requires communication on many levels, including between cells and between organelles within a cell. For example, mitochondria and plastids have been proposed to be sensors of environmental stress and to coordinate their responses. Here we present evidence for communication between mitochondria and chloroplasts during leaf and root development, based on genetic and physical interactions between three Mechanosensitive channel of Small conductance-Like (MSL) proteins from Arabidopsis thaliana. MSL proteins are Arabidopsis homologs of the bacterial Mechanosensitive channel of Small conductance (MscS), which relieves cellular osmotic pressure to protect against lysis during hypoosmotic shock. MSL1 localizes to the inner mitochondrial membrane, while MSL2 and MSL3 localize to the inner plastid membrane and are required to maintain plastid osmotic homeostasis during normal growth and development. In this study, we characterized the phenotypic effect of a genetic lesion in MSL1, both in wild type and in msl2 msl3 mutant backgrounds. msl1 single mutants appear wild type for all phenotypes examined. The characteristic leaf rumpling in msl2 msl3 double mutants was exacerbated in the msl1 msl2 msl3 triple mutant. However, the introduction of the msl1 lesion into the msl2 msl3 mutant background suppressed other msl2 msl3 mutant phenotypes, including ectopic callus formation, accumulation of superoxide and hydrogen peroxide in the shoot apical meristem, decreased root length, and reduced number of lateral roots. All these phenotypes could be recovered by molecular complementation with a transgene containing a wild type version of MSL1. In yeast-based interaction studies, MSL1 interacted with itself, but not with MSL2 or MSL3. These results establish that the abnormalities observed in msl2 msl3 double mutants is partially dependent on the presence of functional MSL1 and suggest a possible role for communication between plastid and mitochondria in seedling development.
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Morphometric analysis of young petiole galls on the narrow-leaf cottonwood, Populus angustifolia, by the sugarbeet root aphid, Pemphigus betae. PROTOPLASMA 2017; 254:203-216. [PMID: 26739691 PMCID: PMC5216080 DOI: 10.1007/s00709-015-0937-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/21/2015] [Indexed: 05/06/2023]
Abstract
An insect-induced gall is a highly specialized structure resulting from atypical development of plant tissue induced by a reaction to the presence and activity of an insect. The insect induces a differentiation of tissues with features and functions of an ectopic organ, providing nutrition and protection to the galling insect from natural enemies and environmental stresses. In this anatomical and cytological study, we characterized how the gall-inducing aphid Pemphigus betae reshapes the leaf morphology of the narrow-leaf cottonwood Populus angustifolia to form a leaf fold gall. Young galls displayed a bend on one side of the midvein toward the center of the leaf and back to create a fold on the abaxial side of the leaf. This fold was formed abaxially by periclinal and anticlinal divisions, effectively eliminating intercellular spaces from the spongy parenchyma. Galls at this stage exhibited both cell hypertrophy and tissue hyperplasia. Cells on the adaxial surface were more numerous and smaller than cells near the abaxial surface were, creating the large fold that surrounds the insect. Mesophyll cells exhibited some features typical of nutritive cells induced by other galling insects, including conspicuous nucleolus, reduced and fragmented vacuole, smaller and degraded chloroplasts, and dense cytoplasm compared to ungalled tissue. Even though aphids feed on the contents of phloem and do not directly consume the gall tissue, they induce changes in the plant vascular system, which lead to nutrient accumulation to support the growing aphid numbers in mature galls.
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Abstract
Little has been written about the role of the peer group in the lives of adolescent mothers. There has been speculation that an adolescent mother's peer relationships change as a result of pregnancy andparenthood. The literature indicates that peers become less able to provide a support system. Little empirical evidence has been provided to support this speculation. This study assessed a sample of 46 adolescent mothers on the amounts and types of supportprovided byfriends as compared to relatives and examined peer support in relation to parenting stress. The Inventory of Social Contacts measured levels of perceived child-rearing, emotional, and material support and interference from family and friends. The Parenting Stress Index assessed self-reported parenting stress arising from child and parent characteristics. Results of repeated-measures ANOVAs and Pearson correlations indicated that, as compared to family, friends provide more emotional support and less interference. Parenting stress is buffered more effectively by the support that is provided by friends.
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Novel whole body plethysmography system for the continuous characterization of sleep and breathing in a mouse. J Appl Physiol (1985) 2011; 112:671-80. [PMID: 22134700 DOI: 10.1152/japplphysiol.00818.2011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sleep is associated with marked alterations in ventilatory control that lead to perturbations in respiratory timing, breathing pattern, ventilation, pharyngeal collapsibility, and sleep-related breathing disorders (SRBD). Mouse models offer powerful insight into the pathogenesis of SRBD; however, methods for obtaining the full complement of continuous, high-fidelity respiratory, electroencephalographic (EEG), and electromyographic (EMG) signals in unrestrained mice during sleep and wake have not been developed. We adapted whole body plethysmography to record EEG, EMG, and respiratory signals continuously in unrestrained, unanesthetized mice. Whole body plethysmography tidal volume and airflow signals and a novel noninvasive surrogate for respiratory effort (respiratory movement signal) were validated against simultaneously measured gold standard signals. Compared with the gold standard, we validated 1) tidal volume (correlation, R(2) = 0.87, P < 0.001; and agreement within 1%, P < 0.001); 2) inspiratory airflow (correlation, R(2) = 0.92, P < 0.001; agreement within 4%, P < 0.001); 3) expiratory airflow (correlation, R(2) = 0.83, P < 0.001); and 4) respiratory movement signal (correlation, R(2) = 0.79-0.84, P < 0.001). The expiratory airflow signal, however, demonstrated a decrease in amplitude compared with the gold standard. Integrating respiratory and EEG/EMG signals, we fully characterized sleep and breathing patterns in conscious, unrestrained mice and demonstrated inspiratory flow limitation in a New Zealand Obese mouse. Our approach will facilitate studies of SRBD mechanisms in inbred mouse strains and offer a powerful platform to investigate the effects of environmental and pharmacological exposures on breathing disturbances during sleep and wakefulness.
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The administration of an oral carbohydrate-containing fluid prior to major elective upper-gastrointestinal surgery preserves skeletal muscle mass postoperatively—a randomised clinical trial. Clin Nutr 2005; 24:32-7. [PMID: 15681099 DOI: 10.1016/j.clnu.2004.06.009] [Citation(s) in RCA: 166] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Accepted: 06/18/2004] [Indexed: 12/21/2022]
Abstract
AIM Recent evidence suggests that the provision of energy-containing fluids is safe and may impact positively on markers of recovery. The aims of this study were to assess the tolerance of preoperative carbohydrate fluid administration and to determine its effect on postoperative metabolic and clinical responses. METHODS Patients admitted to the Royal Infirmary of Edinburgh for major, elective abdominal surgery were recruited to this double-blind, randomised study and received either a placebo drink or carbohydrate (12.6g/100ml) drink (CHOD). Patients consumed 800 ml of their drink on the evening before surgery and 400 ml on the day of surgery 2-3 h before the induction of anaesthesia. Nutritional status was determined using body mass index (BMI) and upper arm anthropometry; all measurements were taken preoperatively, postoperatively and at discharge. Blood glucose and insulin concentrations were also measured preoperatively and on the first post operative day. Length of hospital stay (LOS) and postoperative complications were recorded. RESULTS Seventy-two patients were recruited and 65 (34 male:31 female) completed this study. Thirty-four patients were randomised to receive the placebo drink (control group) and 31 patients to receive the carbohydrate drink (CHOD group). Groups were well-matched in terms of gender and age. There were no differences between the two groups at baseline for BMI (control: -25.1+/-1.7 kg/m2; CHOD -25.2+/-1.2 kg/m2), upper arm anthropometry or surgical procedure. At discharge loss of muscle mass (arm muscle circumference) was significantly greater in the control group when compared with the CHOD group (control: -1.1+/-0.15 cm; CHOD: -0.5+/-0.16 cm; P<0.05). Baseline insulin (control: 20.7+/-4.9 mU/l; CHOD: 24.6+/-6.2 mU/l) and glucose (control: 6.0+/-1.4 mmol/l; CHOD 5.7+/-1.4 mmol/l) were comparable in the two groups and did not differ postoperatively. No complications were recorded as a result of preoperative fluid consumption. Postoperative morbidity occurred in six patients from each group. Median LOS in the control group was 10 days (IQR=6), and 8 days (IQR=4) in the CHOD group. CONCLUSION Preoperative consumption of carbohydrate-containing fluids is safe. Provision of a carbohydrate energy source prior to surgery may attenuate depletion of muscle mass after surgery. Further studies are required to determine if this preservation of muscle mass is reflected in improved function and reduced rehabilitation time.
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Problems and challenges in the history of Canadian science and technology revisited: the making of a bibliography. SCIENTIA CANADENSIS 2001; 11:19-27. [PMID: 11612362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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Abstract
After successful liver transplantation (LTx), excessive weight gain is common among recipients. This rapid change in body morphology has been attributed to immunosuppressive regimens. The liver's role as a metabolic sensor and its autonomic innervation are pivotal in relaying humoral and neural information to the hypothalamus, where ingestive behavior is determined and has largely been ignored. We examined and assessed the contribution of drugs, energy intake, and energy expenditure on weight gain after LTx. Twenty-three patients were followed up at 3-mo intervals after LTx. Energy expenditure was measured by indirect calorimetry and dietary intake by diet diaries, and body composition was assessed with anthropometry and multifrequency bioelectrical impedance analysis. Cumulative drug doses were calculated, and associations between body composition and immunosuppressive regimens and energy expenditure were examined. Nine months after LTx, 20 of 23 (87%) recipients were overweight or obese, despite three-fourths of this cohort being on weight-reduction regimens. After LTx, a decrease in measured energy expenditure was observed (60.3 +/- 1.6 kJ/kg of body cell mass pre-LTx versus 53.7 +/- 2.2 kJ/kg of body cell mass after 9 mo; P < 0.05). Multiple stepwise regression analysis showed that, when adjusted for body weight, the strongest predictor of fat mass at 9 mo after LTx was resting energy expenditure. Weight gain after LTx is not predicted by immunosuppressive drug dosage. The strong association between weight gain and energy economy might be a consequence of the loss of hepatic metabolic integration and accelerated further by increased energy intake. Effective management of weight gain will not be achieved until the mechanisms involved in altered energy homeostasis are elucidated.
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Abstract
BACKGROUND The liver plays a central role in ingestive behavior; alterations in metabolic signaling to the brain stem as a result of chronic liver disease could influence intake. OBJECTIVE We examined the influence of metabolic sequelae of liver disease on nutrient intake and nutritional status. DESIGN Nutritional status and spontaneous dietary intake were examined in 65 cirrhotic patients and 14 control subjects. The response to feeding was investigated in 14 control subjects and a subgroup of 31 cirrhotic patients. Comparisons were made between patients with primary biliary cirrhosis (PBC) and hepatocellular cirrhosis (HC). RESULTS Patients were nutritionally depleted. The fasting rate of lipid oxidation in the HC group was greater than in the control group (P < 0.01). In the fasting state, only HC patients were hyperinsulinemic [121.2+/-78.5 compared with 41.3+/-18.6 pmol/L in control subjects (P < 0.001) and 64.7+/-15.8 pmol/L in PBC patients (P < 0.05)] and this persisted during the response to feeding. In the fed state, the magnitude of change in carbohydrate oxidation was greatest in the HC group (HC: 34.6%; control: 23.1%; PBC: 25.2%). Carbohydrate and energy intakes of the HC group were lower than in control subjects (carbohydrate: 193+/-38.3 compared with 262+/-48.1 g/d, P < 0.05; energy: 6.29+/-1.40 compared with 9.0+/-2.12 MJ/d, P < 0.05). CONCLUSIONS Reductions in carbohydrate intake could be mediated by hyperinsulinemia and compounded by preferential uptake of carbohydrate. This may enhance gastrointestinal satiety signaling and contribute to hypophagia.
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Abstract
Weight loss is common in patients with pancreatic cancer; however, the nature and progress of their nutritional depletion are not well documented. In this study, pre-illness weight and duration of weight loss were recorded in 20 patients with histologically confirmed unresectable cancer of the pancreas. Patients then underwent nutritional analysis at monthly intervals until death. The median period of assessment was 27 weeks (interquartile range 22.5-38.0 weeks). At the time of diagnosis, all patients had lost weight [median 14.2% (10.0-20.0%) of pre-illness stable weight], and this weight loss was progressive, increasing to a median of 24.5% by the time of the last assessment (P =0.0004). Body mass index was significantly reduced from a pre-illness median value of 24.9 kg m-2 (22.4-27.4 kg m-2) to 20.7 kg m-2 (19.5-23.6 kg m-2) at the time of diagnosis and further to 17.7 kg m-2 (16.6-23.1 kg m-2) just before death (P =0.0003). Further evidence of tissue depletion was evident from the significant reductions in lean body mass [43.4 kg (36.9-53.0 kg) to 40.1 kg (33.5-50.7 kg) P =0.008] and fat mass [12.5 kg (8.9-17.8 kg) to 9.6 kg (6.3-15.1 kg) P =0.03). This study confirms that the majority of patients with unresectable pancreatic cancer have already undergone significant weight loss by the time of diagnosis and that the natural history of this process is one of inexorable progression. These results highlight the need for selective non-toxic therapeutic intervention to attenuate cachexia and indicate that such interventions should be instituted early in the course of the disease.
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Munchausen syndrome by proxy: an exploratory study of pediatric nurses' knowledge and involvement. J Pediatr Nurs 1994; 9:313-20. [PMID: 7815291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The awareness and involvement of pediatric nurses in the type of child abuse known as Munchausen syndrome by proxy (MSBP) was explored in this study. A questionnaire assessing knowledge about and extent of involvement in the identification of MSBP cases and demographic information was completed by 320 registered nurses (RNS) employed at a children's hospital. Fewer than half of the subjects (47%) responded that they had heard of MSBP. Those who had heard of MSBP demonstrated only a moderate level of knowledge of the signs and signals of the syndrome. Thirty-four percent of those nurses who had heard of MSBP had been involved in the detection of cases. Findings suggest that it might be important for pediatric hospitals to include information about MSBP in their own required classes or in-house seminars.
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Evaluation of multi-frequency bio-impedance analysis for the assessment of extracellular and total body water in surgical patients. Clin Sci (Lond) 1994; 86:479-85. [PMID: 8168344 DOI: 10.1042/cs0860479] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. Multi-frequency bio-impedance analysis has been used to estimate extracellular and total body water in a heterogeneous group of 43 surgical patients (23 males, 20 females). 2. Radioisotope-dilution methods were used for the measurement of extracellular and total body water. 3. Resistance and reactance were measured between wrist and ankle at frequencies from 5 kHz to 1 MHz. 4. Extracellular and total body water were estimated by multiple stepwise regression using the radioisotope values as the dependent variables. The parameters included in the regression were: resistance and reactance at each frequency, body habitus parameters, plasma albumin and plasma sodium. 5. The standard errors of the estimates between the measured and estimated values were 1.73 litres (coefficient of variation 9.6%) and 2.17 litres (coefficient of variation 6.0%) for extracellular and total body water, respectively. 6. These errors represent a useful improvement relative to those obtained from anthropometric estimates. However, the improvements relative to the use of a single frequency (50 kHz) are not clinically significant.
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Confirmation of the modified Bean model from simulations of superconducting vortices. PHYSICAL REVIEW LETTERS 1994; 72:1268-1271. [PMID: 10056665 DOI: 10.1103/physrevlett.72.1268] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Transport and boundary scattering in confined geometries: Analytical results. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 48:15209-15217. [PMID: 10008056 DOI: 10.1103/physrevb.48.15209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Abstract
Two computerized axial tomographic sections, one taken just below the coracoid process and the other about 2.5 cm proximal to the interepicondylar line, were used to determine glenoid version and humeral torsion in 19 patients with recurrent anterior glenohumeral joint dislocation and in 23 controls. Analysis of interobserver variation revealed the method to be reliable. There was no difference in glenoid version between the two groups. However, humeral torsion was greater in patients (153 degrees) than in controls (144 degrees). It appears that increased humeral torsion may predispose to glenohumeral joint dislocation.
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Assay of timolol in human plasma using gas chromatography with electron-capture detection. JOURNAL OF CHROMATOGRAPHY 1992; 581:277-80. [PMID: 1452619 DOI: 10.1016/0378-4347(92)80282-u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A simple and sensitive gas chromatographic method has been developed for the determination of timolol in plasma using electron-capture detection and propranolol as internal standard. Timolol was extracted using butyl chloride and derivatized using trifluoroacetic anhydride in butyl acetate. The lower detection limit for the assay was found to be 1 ng/ml from 1 ml of plasma. Extracted standards gave within-day precision of 12.55, 9.68 and 3.78% for 1, 20 and 100 ng/ml plasma samples, respectively. A recovery of at least 80% of timolol was found using the extraction method described. The assay was used in a randomized cross-over bioequivalence trial using an oral administration of 20 mg of timolol. Pharmacokinetic parameters compare favourably with other literature values.
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Abstract
The evaluation of nutritional status in surgical patients remains a difficult problem. Bioelectrical impedance analysis (BIA) is a new method of body composition analysis which is easily performed at the bedside. This study determined the accuracy of BIA in the measurement of total body water (TBW) and potassium (TBK) in a heterogeneous group of surgical patients. The resistance and reactance components of impedance were measured with a whole body impedance analyser. Tritiated water dilution and whole body monitoring were the reference methods for TBW and TBK analysis. With the BIA technique the coefficient of variation for the estimation of TBW was 8.1 per cent and for TBK was 6.4 per cent. Allowing for the errors of the reference methods these results show that BIA is of limited value in the estimation of TBW but may provide a useful index of TBK.
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Thermal conductivity of YBa2Cu3O7- delta in a magnetic field: Can kappa (H) probe the vortex state? PHYSICAL REVIEW LETTERS 1991; 67:3856-3859. [PMID: 10044843 DOI: 10.1103/physrevlett.67.3856] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Theoretical analysis of the thermal conductivity of YBa2Cu3O7- delta single crystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:9508-9513. [PMID: 9998934 DOI: 10.1103/physrevb.44.9508] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Thermal conductivity of Ba-K-Bi-O: A contrast to copper oxide superconductors. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:2684-2687. [PMID: 9995750 DOI: 10.1103/physrevb.42.2684] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Benign giant cell tumour with metastases to bone and lung. One case studied over 20 years. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1990; 72:486-9. [PMID: 2341453 DOI: 10.1302/0301-620x.72b3.2341453] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We report a case of benign giant cell tumour which over a 20-year period has given rise to pulmonary and bony metastases. The indolent nature of these metastases is remarkable, with considerable implications for the long-term management of such cases.
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Evaluation of blood glucose reflectance meters. THE NEW ZEALAND MEDICAL JOURNAL 1988; 101:643. [PMID: 3173879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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The conservative treatment of acromioclavicular dislocation. Review after five years. THE JOURNAL OF BONE AND JOINT SURGERY. BRITISH VOLUME 1987; 69:719-22. [PMID: 3680330 DOI: 10.1302/0301-620x.69b5.3680330] [Citation(s) in RCA: 111] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The treatment of acromioclavicular injuries is controversial; few studies document the late results. We have reviewed 53 patients about five years after conservative management, in nine for subluxation and 44 for dislocation. Subjective and objective results were satisfactory in all cases except for one with painful subluxation, who was the only patient to change her occupation because of the injury. At review, joint stability was demonstrated by improvement in position and by the very small increase in the coracoclavicular gap on stress radiographs.
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31
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Review of an orthopaedic in-patient waiting list. HEALTH TRENDS 1984; 16:14-5. [PMID: 10265059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A review of 950 patients who had waited for more than one year for orthopaedic treatment at a large District General Hospital was undertaken. Searches of medical records eliminated 193 patients who had already had operations, but, whose names had not been removed from the list. Of the remaining 757 patients, 48% indicated their wish to remain on the list. This proportion was lowest for: the under 45 year old age group (43%), the over 75s (36%), patients awaiting less complex procedures (35%) and those with waiting times longer than five years (31%).
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Safety and efficacy of albuterol aerosol in the relief of bronchospasm. ANNALS OF ALLERGY 1981; 47:392-3. [PMID: 7305079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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The prevention of post-appendicectomy sepsis by metronidazole and cefazolin: a controlled double blind trial. THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1980; 50:429-33. [PMID: 7000063 DOI: 10.1111/j.1445-2197.1980.tb04158.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A double blind, randomized, controlled trial was carried out at two hospitals to try the effect of metronidazole, which is effective against most anaerobes, and cefazolin, which is effective against many aerobic organisms, singly and in combination, on the incidence of wound sepsis following appendicectomy. Patients were placed at random into one of four groups; to receive metronidazole and placebo, cefazolin and placebo, metronidazole and cefazolin, or double placebo. Patients with generalized peritonitis were excluded for ethical reasons. Treatment was started before operation and continued eight-hourly for twenty-four hours. All patients in the trial were followed up at about two weeks after discharge from hospital and their wounds inspected. Two hundred and seventy-one patients were assessed. Sepsis rates at the two hospitals were similar. On the untreated controls, 30% discharged pus from their wounds, and in the groups receiving one drug only, about 20%. In those receiving both drugs the infection rate was 3%, a highly significant difference from that in the other three groups.
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Abstract
The commonly used nitration colorimetric method for urgent paracetamol estimation suffers from interference by salicylates and salicylamide. This communication describes a simple modification which eliminates this interference without affecting either the recovery or precision of the method. The results obtained were briefly compared with those obtained by an established gas chromatographic procedure.
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Abstract
Abstract
I describe a sensitive, specific, automated method for determination of mercury in urine by the "flameless atomic absorption" technique. One can analyze 20 samples per hour, with less than 0.5-ml samples of urine. The detection limit is 0.01 mumol/liter (2mug/liter) and the mean coefficient of variation 12%. The procedure is being used to monitor mercury excretion by workers exposed to mercury.
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Automated method for determination of mercury in urine. Clin Chem 1976; 22:1604-7. [PMID: 975503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
I describe a sensitive, specific, automated method for determination of mercury in urine by the "flameless atomic absorption" technique. One can analyze 20 samples per hour, with less than 0.5-ml samples of urine. The detection limit is 0.01 mumol/liter (2mug/liter) and the mean coefficient of variation 12%. The procedure is being used to monitor mercury excretion by workers exposed to mercury.
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Abstract
A rapid fluorimetric procedure for the determination of the fungicide 5-fluorocytosine in serum is described. The method is high in precision (S.D. 1.6 mug/ml at 50 mug/ml) and specificity and can be performed in 60-90 minutes. The results obtained for samples from six patients showed excellent agreement with those obtained by traditional microbiological methods.
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Some social consequences of technological success. Hastings Cent Rep 1974; 4:4-6. [PMID: 4426745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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39
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The penetration of doxycycline, oxytetracycline and minocycline into sputum. THE NEW ZEALAND MEDICAL JOURNAL 1974; 80:300-2. [PMID: 4531566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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User and non-user differences in symbol meaning of Rorschach content. J Clin Psychol 1974; 30:208-13. [PMID: 4132665 DOI: 10.1002/1097-4679(197404)30:2<208::aid-jclp2270300227>3.0.co;2-o] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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