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1.
Sci Rep ; 9(1): 19613, 2019 12 23.
Article in English | MEDLINE | ID: mdl-31873100

ABSTRACT

Plants adapted to extreme conditions can be at high risk from climate change; arctic-alpine plants, in particular, could "run out of space" as they are out-competed by expansion of woody vegetation. Mountain regions could potentially provide safe sites for arctic-alpine plants in a warmer climate, but empirical evidence is fragmentary. Here we present a 24,000-year record of species persistence based on sedimentary ancient DNA (sedaDNA) from Lake Bolshoye Shchuchye (Polar Urals). We provide robust evidence of long-term persistence of arctic-alpine plants through large-magnitude climate changes but document a decline in their diversity during a past expansion of woody vegetation. Nevertheless, most of the plants that were present during the last glacial interval, including all of the arctic-alpines, are still found in the region today. This underlines the conservation significance of mountain landscapes via their provision of a range of habitats that confer resilience to climate change, particularly for arctic-alpine taxa.


Subject(s)
Climate Change , Ecosystem , Plant Development , Plants/classification , Arctic Regions
2.
R Soc Open Sci ; 5(1): 170736, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29410798

ABSTRACT

Detailed investigation of landforms and their underlying deposits on the eastern margin of Fenland, East Anglia, demonstrated that they represent a series of glaciofluvial delta-fan and related sediments. Associated with these deposits are glacially dislocated sediments including tills, meltwater and pre-existing fluvial sediments. These 'Skertchly Line' deposits occur in the context of a substantial ice lobe that entered Fenland from the N to NE, dammed the streams entering the basin and caused glacial lakes to form in the valleys on the margins. Bulldozing by the ice lobe caused a series of ice-pushed ridges to form at the dynamic margin, especially at the ice maximum and during its retreat phases. Meltwater formed a series of marginal fans that coalesced into marginal accumulations in the SE of the basin. The ice lobe is named the Tottenhill glaciation. Further investigations of the Fenland margin have revealed the extent of the Tottenhill glaciation in the Fenland Basin, to the south and west, in sufficient detail to demonstrate the nature of the Tottenhill ice lobe and the landscape left on deglaciation. The ice lobe is likely to have been prone to surging. This is indicated by the low gradient of the ice lobe, the presence of underlying ductile Mesozoic clays, the evidence of ice-marginal flooding and the presence of arcuate glaciotectonic push moraines. Regional correlation, supported by independent numerical geochronology, indicates that the glaciation occurred ca 160 ka, i.e. during the late Middle Pleistocene, Marine Isotope Stage (MIS) 6, the Wolstonian Stage. Comparison and correlation across the southern North Sea Basin confirms that the glaciation is the equivalent of that during the Late Saalian Drenthe Stadial in The Netherlands. The implications of this correlation are presented. Before the glaciation occurred, the Fenland Basin did not exist. It appears to have been initiated by a subglacial tunnel valley system beneath the Anglian (=Elsterian, MIS 12) ice sheet. During the subsequent Hoxnian (=Holsteinian; approx. MIS 11) interglacial, the sea invaded the drainage system inherited following the glacial retreat. The evolution through the subsequent ca 200 ka Early to Middle Wolstonian substages, the interval between the Hoxnian (Holsteinian) temperate Stage and the Wolstonian glaciation, represents a period during which fluvial and periglacial activity modified the landscape under cold climates, and organic sediments were laid down during a warmer event. Palaeolithic humans were also periodically present during this interval, their artefacts having been reworked by the subsequent glaciation. The deglaciation was followed by re-establishment of the rivers associated with the deposition of Late Wolstonian (Warthe Stadial) gravels and sands, and later, deposits of the Ipswichian interglacial (=Eemian, approx. MIS 5e) including freshwater, then estuarine sediments. Subsequent evolution of the basin occurred during the Devensian Stage (=Weichselian, MIS 5d-2) under predominantly cold, periglacial conditions.

3.
Transplant Proc ; 49(9): 2070-2075, 2017 Nov.
Article in English | MEDLINE | ID: mdl-29149963

ABSTRACT

BACKGROUND: Urinary tract infections (UTIs) are the commonest infectious complication in kidney transplant recipients (KTRs). No recommendations exist regarding treatment of asymptomatic bacteriuria. We aimed to identify potential risk factors and microbiological profile for UTIs, the role of treatment of asymptomatic bacteriuria, and effects on graft outcomes of bacteriuria within the first year post-transplantation. METHODS: We performed a retrospective analysis of UTIs in KTRs transplanted between January 2012 and December 2013 in 2 transplantation centers. Patients were routinely commenced on prophylactic sulfamethoxazole-trimethoprim. Clinical and microbiological data were analyzed for the first year following transplantation. RESULTS: In all, 276 KTRs were evaluated; 67% were men, with a mean age of 51 years. At 12 months post-transplantation 158 (57%) KTRs had no bacteriuria, 75 (27%) had asymptomatic bacteriuria, 21 (8%) had symptomatic UTIs without further complication, and 22 (8%) with UTIs developed either pyelonephritis or urosepsis. Most frequent pathogens identified were Enterococcus faecalis and Escherichia coli, and 36% of organisms were multidrug resistant. Female sex was a risk factor for infection (P = .002), and presence of a double-J ureteral stent significantly increased the risk of asymptomatic bacteriuria and symptomatic UTIs (P = .003). Diabetes, age, and prior transplantation did not increase risk. Presence of infection was not associated with increased rejection, with similar renal function at 12 months. For episodes of bacteriuria (n = 420, asymptomatic n = 324), untreated asymptomatic bacteriuria (n = 185) followed by symptomatic UTI with the same organism was significantly higher (P = .002) compared with cases of treated asymptomatic bacteriuria (n = 139). CONCLUSION: Bacteriuria post-kidney transplantation is common, affecting nearly half of KTRs in the first year after transplantation. Treatment of asymptomatic bacteriuria may be beneficial to prevent subsequent episodes of symptomatic UTIs.


Subject(s)
Bacteriuria/drug therapy , Kidney Transplantation/adverse effects , Postoperative Complications/drug therapy , Urinary Tract Infections/prevention & control , Adult , Bacterial Infections/drug therapy , Bacteriuria/complications , Enterococcus faecalis/isolation & purification , Escherichia coli/isolation & purification , Female , Humans , Male , Middle Aged , Postoperative Complications/microbiology , Pyelonephritis/etiology , Retrospective Studies , Risk Factors , Trimethoprim, Sulfamethoxazole Drug Combination/therapeutic use , Urinary Tract Infections/etiology
4.
Anal Chem ; 87(1): 376-80, 2015 Jan 06.
Article in English | MEDLINE | ID: mdl-25495958

ABSTRACT

A technological development is described through which the stable carbon-, oxygen-, and nonexchangeable hydrogen-isotopic ratios (δ(13)C, δ(18)O, δ(2)H) are determined on a single carbohydrate (cellulose) sample with precision equivalent to conventional techniques (δ(13)C 0.15‰, δ(18)O 0.30‰, δ(2)H 3.0‰). This triple-isotope approach offers significant new research opportunities, most notably in physiology and medicine, isotope biogeochemistry, forensic science, and palaeoclimatology, when isotopic analysis of a common sample is desirable or when sample material is limited.


Subject(s)
Carbon Isotopes/analysis , Cellulose/chemistry , Hydrogen/analysis , Mass Spectrometry/methods , Oxygen Isotopes/analysis
5.
J Environ Qual ; 39(1): 260-73, 2010.
Article in English | MEDLINE | ID: mdl-20048314

ABSTRACT

Remote sensing techniques have potential for peatland monitoring, but most previous work has focused on spectral approaches that often result in poor discrimination of cover types and neglect structural information. Peatlands contain structural "microtopes" (e.g., hummocks and hollows) which are linked to hydrology, biodiversity and carbon sequestration, and information on surface structure is thus a useful proxy for peatland condition. The objective of this work was to develop and test a new eco-hydrological mapping technique for ombrotrophic (rain-fed) peatlands using a combined spectral-structural remote sensing approach. The study site was Wedholme Flow, Cumbria, UK. Airborne light dectection and ranging (LiDAR) data were used with IKONOS data in a combined multispectral-structural approach for mapping peatland condition classes. LiDAR data were preprocessed so that spatial estimates of minimum and maximum land surface height, variance and semi-variance (from semi-variogram analysis) were extracted. These were assimilated alongside IKONOS data into a maximum likelihood classification procedure, and thematic outputs were compared. Ecological survey data were used to validate the results. Considerable improvements in thematic separation of peatland classes were achieved when spatially-distributed measurements of LiDAR variance or semi-variance were included. Specifically, the classification accuracy improved from 71.8% (IKONOS data only) to 88.0% when a LiDAR semi-variance product was used. Of note was the improved delineation of management classes (including Eriophorum bog, active raised bog and degraded raised bog). The application of a combined textural-optical approach can improve land cover mapping in areas where reliance on purely spectral discrimination approaches would otherwise result in considerable thematic uncertainty.


Subject(s)
Environmental Monitoring/methods , Soil , Spacecraft , Wetlands , United Kingdom , Water Movements
7.
Brain Res Dev Brain Res ; 129(2): 135-45, 2001 Aug 23.
Article in English | MEDLINE | ID: mdl-11506858

ABSTRACT

Effects of gestational ethanol exposure on the trafficking of the NMDA receptor complex were investigated. Studies focused on three distinct processes in NMDA receptor translocation: (1) the level of gene transcription (2) nascent NMDA receptor subunits (NR) associated with the endoplasmic reticulum bound chaperone protein calnexin and (3) NMDA receptors associated with the cell surface anchoring protein PSD-95. Forebrain mRNA and membrane proteins were isolated from postnatal day 1 rat pups from prenatally ethanol exposed, pair-fed and ad libitum experimental groups. Ribonuclease protection assays were carried out to determine the levels of NR2A, NR2B, and NR2C mRNA within the treatment groups determined. Results indicated that gestational ethanol exposure did not affect the gene transcription of the NR2 subunits. Immunoprecipitation experiments were conducted with an anti-calnexin antibody or an anti-PSD-95 antibody and the immunoprecipitates probed for NR1 and NR2 subunits. Within the anti-calnexin immunoprecipitates, no NR2A, NR2B or NR2C subunits were detectable, but a significant pool of NR1 subunits was identified. These findings suggest that NR1 subunits but not NR2 subunits are associated with calnexin within the endoplasmic reticulum. Further, gestational ethanol exposure significantly increased the NR1 polypeptide levels in the anti-calnexin immunoprecipitate. Anti-PSD-95 immunoprecipitates revealed an abundance of NR1 and NR2B subunits, and these complexes were unaffected by gestational ethanol exposure. No NR2A or NR2C subunits were detected. These results suggest that gestational ethanol exposure significantly affects the assembly and transport of NMDA receptors. Gestational ethanol exposure may not alter the composition of the PSD-95 associated NMDA receptor complex.


Subject(s)
Ethanol/administration & dosage , Prenatal Exposure Delayed Effects , Prosencephalon/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Animals , Body Weight/drug effects , Calcium-Binding Proteins/metabolism , Calnexin , Cell Membrane/metabolism , Disks Large Homolog 4 Protein , Ethanol/pharmacology , Female , Intracellular Signaling Peptides and Proteins , Male , Membrane Proteins , Mothers , Nerve Tissue Proteins/metabolism , Peptide Fragments/metabolism , Pregnancy , Protein Isoforms/genetics , RNA, Messenger/metabolism , Rats , Rats, Sprague-Dawley , Receptors, N-Methyl-D-Aspartate/chemistry , Receptors, N-Methyl-D-Aspartate/genetics , Transcription, Genetic
8.
Crit Care Med ; 29(7): 1325-31, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11445679

ABSTRACT

OBJECTIVE: In the critically ill, respiratory muscle strength usually has been assessed by measuring maximum inspiratory pressure. The maneuver is volitional, and results can be unreliable. The nonvolitional technique of bilateral anterolateral magnetic stimulation of the phrenic nerves, producing twitch transdiaphragmatic pressure, has been successful in normal subjects and ambulatory patients. In this study we used the technique in the intensive care unit and explored the measurement of twitch endotracheal tube pressure as a less invasive technique to assess diaphragmatic contractility. DESIGN: Clinical study to quantify diaphragm strength in the intensive care unit. SETTING: Patients from three London teaching hospital intensive care units and high-dependency units. PATIENTS: Forty-one intensive care patients were recruited. Of these, 33 (20 men, 13 women) were studied. INTERVENTIONS: Esophageal and gastric balloon catheters were passed through the anaesthetized nose, and an endotracheal tube occlusion device was placed in the ventilation circuit, next to the endotracheal tube. Two 43-mm magnetic coils were placed anteriorly on the patient's neck, and the phrenic nerves were stimulated magnetically. MEASUREMENTS AND MAIN RESULTS: On phrenic nerve stimulation, twitch gastric pressure, twitch esophageal pressure, twitch transdiaphragmatic pressure, and twitch endotracheal tube pressure were measured. Forty-one consecutive patients consented to take part in the study, and twitch pressure data were obtained in 33 of these. Mean transdiaphragmatic pressure was 10.7 cm H2O, mean twitch esophageal pressure was 6.7 cm H2O, and mean twitch endotracheal tube pressure was 6.7 cm H2O. The mean difference between twitch esophageal pressure and twitch endotracheal tube pressure was 0.02 cm H2O. Correlation of the means of twitch endotracheal tube pressure to twitch esophageal pressure was 0.93, and that for twitch endotracheal tube pressure to transdiaphragmatic pressure was 0.78. CONCLUSIONS: Transdiaphragmatic pressure can be measured in the critically ill to give a nonvolitional assessment of diaphragm contractility, but not all patients can be studied. At present, the relationship of twitch endotracheal tube pressure to transdiaphragmatic pressure is too variable to reliably represent a less invasive measure of diaphragm strength.


Subject(s)
Diaphragm/physiopathology , Esophagus/physiopathology , Phrenic Nerve , Respiratory Function Tests , Respiratory Paralysis/diagnosis , Adult , Aged , Diaphragm/innervation , Female , Humans , Intensive Care Units , Intermittent Positive-Pressure Ventilation , Intubation, Intratracheal , Magnetics , Male , Middle Aged , Muscle Contraction , Pressure , Respiratory Muscles/innervation , Respiratory Muscles/physiopathology , Ventilator Weaning
9.
Am J Respir Crit Care Med ; 163(6): 1400-3, 2001 May.
Article in English | MEDLINE | ID: mdl-11371408

ABSTRACT

Exercise intolerance is a feature of chronic heart failure (CHF). We hypothesized that excessive loading of the respiratory muscle pump might contribute to exertional breathlessness. One marker of excessive muscle-loading is slowing of maximum relaxation rate (MRR) and, therefore, to test our hypothesis, we investigated the effect of exhaustive treadmill walking on inspiratory muscle MRR in patients with CHF. We studied eight stable patients with mild-moderate CHF walking on a treadmill until termination because of severe dyspnea. Inspiratory muscle MRR was determined from esophageal pressure (Pes) change during submaximal sniffs (Sn) before and immediately after exercise to a mean (SD) minute ventilation of 77 () L/min. For comparison, nine healthy subjects performed a similar protocol; exercise was terminated either by severe dyspnea or when minute ventilation reached 100 L/min. There were no significant differences in terms of heart rate, respiratory rate, tidal volume, or inspiratory duty cycle at cessation of exercise. The mean slowing of Sn Pes MRR in the first minute after termination of exercise in the CHF group was 22.4% and in the normal control group it was 2.8% (p < 0.01). Our data show that slowing of inspiratory muscle relaxation rate occurs in patients with CHF walking to severe breathlessness. We conclude that severe loading of the inspiratory muscles is a feature of exertional dyspnea in CHF.


Subject(s)
Dyspnea/etiology , Exercise Test , Heart Failure/physiopathology , Inspiratory Capacity , Muscle Relaxation , Respiratory Muscles/physiopathology , Walking , Adult , Case-Control Studies , Chronic Disease , Forced Expiratory Volume , Heart Failure/complications , Heart Failure/diagnosis , Heart Rate , Humans , Middle Aged , Spirometry , Tidal Volume , Time Factors
11.
Intensive Care Med ; 26(8): 1065-75, 2000 Aug.
Article in English | MEDLINE | ID: mdl-11030162

ABSTRACT

OBJECTIVE: Anterior magnetic stimulation (aMS) of the phrenic nerves is a new method for the assessment of diaphragm contractility that might have particular applications for the clinical assessment of critically ill patients who are commonly supine. DESIGN: We compared aMS with existing techniques for measurement of diaphragm weakness and fatigue in 10 normal subjects, 27 ambulant patients with suspected diaphragm weakness and 10 critically ill patients. SETTING: Laboratory and intensive care unit of two university hospitals. RESULTS: Although aMS was not demonstrably supramaximal in normal subjects, the mean value of twitch transdiaphragmatic pressure (Tw Pdi) obtained at 100% of stimulator output, 23.7 cmH2O, did not differ significantly from that obtained with bilateral supramaximal electrical stimulation (ES), 24.9 cmH2O, or bilateral anterior magnetic phrenic nerve stimulation (BAMPS), 27.3 cmH2O. A fatiguing protocol produced a 20 % fall in aMS-Tw Pdi and a 19% fall in BAMPS-Tw Pdi; the fall in aMS-Tw Pdi correlated with the fall in BAMPS-Tw Pdi (r2 = 0.84, p = 0.03) indicating that aMS can detect diaphragm fatigue. In ambulant patients aMS agreed closely with existing measures of diaphragm strength. The maximal sniff Pdi correlated with both the aMS-Tw Pdi (r2 = 0.60, p < 0.0001) and the BAMPS-Tw Pdi (r2 = 0.65, p < 0.0001) and the aMS-Tw Pdi was a mean (SD) 2.2 (4.3) cmH2O less than BAMPS-Tw Pdi. In addition, aMS correctly identified diaphragm dysfunction in patients studied on the ICU. CONCLUSIONS: We conclude that aMS is of clinical value for the investigation of suspected diaphragm weakness.


Subject(s)
Diaphragm/innervation , Electromagnetic Phenomena , Neuromuscular Diseases/diagnosis , Phrenic Nerve/physiopathology , Respiratory Function Tests/methods , Action Potentials , Adolescent , Adult , Aged , Aged, 80 and over , Analysis of Variance , Diaphragm/physiopathology , Female , Humans , Intensive Care Units , Male , Middle Aged , Reproducibility of Results , Respiration, Artificial , Respiratory Function Tests/instrumentation , Safety , Sensitivity and Specificity , Supine Position
12.
Biomaterials ; 21(18): 1847-59, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10919688

ABSTRACT

Copolymers of 2-methacryloyloxyethylphosphorylcholine (MPC) and lauryl methacrylate (LMA) of molar ratios MPC: LMAX where x = 1, 2 or 4, have been synthesised by two different free-radical polymerisation techniques. The solubility characteristics of the resulting materials were investigated in a variety of water: alcohol solvent mixtures and found to be influenced not only by the molar ratio of MPC: LMA, but also the method of synthesis. A window of solubility was observed for certain copolymers and the alcohol used in the solvent mixture was also found to have a profound influence on the solubility profile of the polymers. These materials were soluble in a wider range of aqueous methanol mixtures compared to aqueous mixtures of higher aliphatic alcohols, such as ethanol or isopropyl alcohol, which was rationalised in terms of the affinity of the phosphorylcholine headgroup for the various alcohols relative to water. 1H nuclear magnetic resonance spectroscopy was used to further examine the solution properties of the copolymers in various solvents. The copolymer MPC: LMA2 was coated onto a variety of substrates from both alcohol-only and water: alcohol solvent systems and the surface properties of the films compared by static and dynamic contact angle, atomic force microscopy (AFM) and attenuated internal reflectance Fourier transform infrared spectroscopy (ATR-IR). The coating formed from the water: alcohol solvent was found to be hydrophilic in nature, possessing spontaneous wettability, whereas films formed from alcohol-only solvents were hydrophobic, and only on conditioning with water were more wettable surfaces attained. This phenomenon was applied in the coating of leukocyte filtration material, where the aqueous-based systems demonstrated lower critical wetting surface tension (CWST) and shorter wetting times relative to both uncoated filters and those coated from alcohol-only systems. The haemocompatibility of the coated filters was equivalent for both coating solvent systems. employed, and far superior when compared to the uncoated control.


Subject(s)
Blood , Coated Materials, Biocompatible/chemical synthesis , Hemofiltration/instrumentation , Methacrylates , Phosphorylcholine/analogs & derivatives , Alcohols , Coated Materials, Biocompatible/chemistry , Drug Design , Humans , Kinetics , Magnetic Resonance Spectroscopy , Microscopy, Electron, Scanning , Polymers , Solubility , Solvents , Spectroscopy, Fourier Transform Infrared , Structure-Activity Relationship , Surface Properties , Water
15.
Aust N Z J Surg ; 69(12): 856-9, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10613284

ABSTRACT

BACKGROUND: Since 1988 the author has used only endoscopic injection of Teflon (polytetrafluoroethylene) paste in the correction of ureteric reflux, in adults and children. METHODS: The present paper reports a series of 32 patients, 18 children and 14 adults, with 45 refluxing ureters so treated. Intra-operative cystogram was carried out and a second Teflon paste injection was given under the same anaesthetic where persistent reflux was demonstrated after the initial Teflon injection, to reduce the number of anaesthetics given. RESULTS: In those patients who consented to a delayed cystogram after the first injection of Teflon, there was a cure rate of 83.3% in children and 70% in adults from that first injection. CONCLUSION: Endoscopic retro-ureteric injection of Teflon paste is done as a day case under general anaesthesia and causes the patient no pain postoperatively. It gives a high cure rate and is an option that should be offered to every patient where a decision has been made to correct ureteric reflux.


Subject(s)
Polytetrafluoroethylene/administration & dosage , Vesico-Ureteral Reflux/therapy , Adult , Child , Child, Preschool , Female , Humans , Injections/methods , Male , Ointments , Ureter , Ureteroscopy
16.
Am J Respir Crit Care Med ; 160(2): 529-34, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10430724

ABSTRACT

Reduced respiratory muscle strength has been reported in chronic heart failure (CHF) in several studies. The data supporting this conclusion come almost exclusively from static inspiratory and expiratory mouth pressure maneuvers (MIP, MEP), which many subjects find difficult to perform. We therefore performed a study using measurements that are less dependent on patient aptitude and also provide specific data on diaphragm strength. In 20 male patients and 15 control subjects we measured MIP and MEP as well as esophageal and transdiaphragmatic pressure during maximal sniffs (Sn Pes, Sn Pdi) and cervical magnetic phrenic nerve stimulation (Tw Pdi). In a subgroup the response to paired phrenic nerve stimulation (pTw Pdi) at interpulse intervals from 10 to 200 ms (5 to 100 Hz) was also determined. As expected, MIP was significantly reduced in the CHF group (CHF, 69.5 cm H(2)O; control, 96.7 cm H(2)O; p = 0.01), but differences were much less marked for Sn Pes (CHF, 95.2 cm H(2)O; control, 104.8 cm H(2)O; p = 0.20) and MEP (CHF, 109.1 cm H(2)O; control, 135.7 cm H(2)O; p = 0.09). Diaphragm strength was significantly reduced (Sn Pdi: CHF, 123.8 cm H(2)O; control 143.5 cm H(2)O; p = 0.04. Tw Pdi: CHF, 21.4 cm H(2)O; control, 28.5 cm H(2)O; p = 0.0005). Paired phrenic nerve stimulation suggested a trend to increased twitch summation at 5 to 20 Hz in CHF, although this did not reach significance. We conclude that mild reduction in diaphragm strength occurs in CHF, possibly because of an increased proportion of slow fibers, but overall strength of the respiratory muscles remains well preserved.


Subject(s)
Diaphragm/physiopathology , Dyspnea/physiopathology , Heart Failure/physiopathology , Respiratory Mechanics/physiology , Respiratory Muscles/physiopathology , Adult , Aged , Electric Stimulation , Humans , Inspiratory Capacity/physiology , Male , Middle Aged , Phrenic Nerve/physiopathology , Plethysmography, Whole Body , Spirometry , Ventricular Function, Left/physiology
17.
Eur Respir J ; 13(2): 379-84, 1999 Feb.
Article in English | MEDLINE | ID: mdl-10065685

ABSTRACT

Diaphragm paralysis is a recognized complication of neuralgic amyotrophy that causes severe dyspnoea. Although recovery of strength in the arm muscles, when affected, is common, there are little data on recovery of diaphragm function. This study, therefore, re-assessed diaphragm strength in cases of bilateral diaphragm paralysis due to neuralgic amyotrophy that had previously been diagnosed at the authors institutions. Fourteen patients were recalled between 2 and 11 yrs after the original diagnosis. Respiratory muscle and diaphragm strength were measured by volitional manoeuvres as maximal inspiratory pressure and sniff transdiaphragmatic pressure. Cervical magnetic phrenic nerve stimulation was used to give a nonvolitional measure of diaphragm strength: twitch transdiaphragmatic pressure. Only two patients remained severely breathless. Ten of the 14 patients had evidence of some recovery of diaphragm strength, in seven cases to within 50% of the lower limit of normal. The rate of recovery was variable: one patient had some recovery after 2 yrs, and the rest took 3 yrs or more. In conclusion, in most patients with diaphragm paralysis due to neuralgic amyotrophy, some recovery of the diaphragm strength occurs, but the rate of recovery may be slow.


Subject(s)
Brachial Plexus Neuritis/physiopathology , Diaphragm/physiopathology , Adult , Aged , Brachial Plexus Neuritis/complications , Dyspnea/etiology , Follow-Up Studies , Forced Expiratory Volume , Humans , Male , Middle Aged , Recovery of Function , Residual Volume , Respiratory Muscles/physiopathology , Respiratory Paralysis/etiology , Respiratory Paralysis/physiopathology , Total Lung Capacity , Vital Capacity
18.
Alcohol Clin Exp Res ; 22(6): 1255-61, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9756040

ABSTRACT

The effects of prenatal ethanol exposure on the NMDAR1 protein expression (postnatal days 1 and 7) and on the developmental profile of the NMDAR2A and NMDAR2B subunits in rat forebrain and hippocampus were investigated. Forebrain and hippocampal membrane proteins were isolated from pups of various ages (postnatal days 1 to 21) from prenatally ethanol exposed, pair-fed and ad libitum control groups. A semiquantitative immunoblot procedure was used with antibodies raised against the NMDAR1, NMDAR2A, and the NMDAR2B subunits to assess the NMDA subunit protein expression in the samples. NMDAR1 protein expression was unaffected by prenatal ethanol exposure at postnatal day 1 or 7 in both the forebrain and hippocampus. NMDAR2A protein expression levels rose rapidly in both forebrain and hippocampus during the time frame of study. Prenatal ethanol exposure caused a significant reduction in protein expression levels of the NMDAR2A in forebrain through postnatal day 14. NMDAR2B protein expression levels were high throughout the study in both forebrain and hippocampus. Prenatal ethanol exposure significantly reduced protein expression of the NMDAR2B in the forebrain (through postnatal day 14) and hippocampus (up to day 7). The results suggest that there may be a link between the depressed expression of the NMDAR2 subunits and the neurodevelopmental disorders associated with fetal ethanol exposure.


Subject(s)
Ethanol/toxicity , Fetal Alcohol Spectrum Disorders/physiopathology , Hippocampus/drug effects , Prosencephalon/drug effects , Receptors, N-Methyl-D-Aspartate/drug effects , Animals , Female , Hippocampus/physiopathology , Male , Pregnancy , Prosencephalon/physiopathology , Rats , Rats, Sprague-Dawley , Receptors, N-Methyl-D-Aspartate/classification , Receptors, N-Methyl-D-Aspartate/physiology
19.
J Appl Physiol (1985) ; 85(4): 1322-8, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9760323

ABSTRACT

The effect of stimulus frequency on the in vivo pressure generating capacity of the human diaphragm is unknown at lung volumes other than functional residual capacity. The transdiaphragmatic pressure (Pdi) produced by a pair of phrenic nerve stimuli may be viewed as the sum of the Pdi elicited by the first (T1 Pdi) and second (T2 Pdi) stimuli. We used bilateral anterior supramaximal magnetic phrenic nerve stimulation and a digital subtraction technique to obtain the T2 Pdi at interstimulus intervals of 999, 100, 50, 33, and 10 ms in eight normal subjects at lung volumes between residual volume and total lung capacity. The reduction in T2 Pdi that we observed as lung volume increased was greatest at long interstimulus intervals, whereas the T2 Pdi obtained with short interstimulus intervals remained relatively stable over the 50% of vital capacity around functional residual capacity. For all interstimulus intervals, the total pressure produced by the pair decreased as a function of increasing lung volume. These data demonstrate that, in the human diaphragm, hyperinflation has a disproportionately severe effect on the summation of pressure responses elicited by low-frequency stimulations; this effect is distinct from and additional to the known length-tension relationship.


Subject(s)
Diaphragm/physiology , Lung Volume Measurements , Muscle Contraction/physiology , Respiratory Mechanics/physiology , Adult , Diaphragm/innervation , Female , Humans , Magnetics , Male , Phrenic Nerve/physiology , Pressure , Vital Capacity
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