202 research outputs found
Assessment of the selectivity of proteinuria by gel filtration
The selectivity of proteinuria was assessed in 25 patients by a gel filtration technique utilising a G 200 Sephadex column. The
results were compared with those obtained using gel diffusion and
immunoprecipitation to assess selectivity. In five patients, where the
protein excretion was less than 1.0 g. per day, the results obtained by
gel filtration through Sephadex were found to be suspect. In the
remaining 20 patients, where the protein excretion was over 1.0 g. per day,
the relationship between the gel filtration selectivity and that determined
by immunoprecipitation could be expressed as a straight line passing through
the origin. The correlation coefficient for this line (0.84) was highly
significant statistically.The selectivities obtained on gel filtration were assessed in the
light of the findings on renal biopsy. Two of the twenty patients with
proteinuria of over 1.0 g. per day had minimal lesion glomerulonephritis.
These patients also had the two highest selectivities in the series.Three of the patients studied had chronic renal failure. These
patients had the lowest, the second lowest, and the fifth lowest selectivities
of the series.Good renal function and minimal glomerular damage appearJto be
associated with selective proteinuria, while poor renal function and severe
glomerular damage appeared to be associated with unselective proteinuria.Five patients with selective proteinuria were treated with steroids.
In two cases the proteinuria disappeared. In a third it fell to trace amounts.Ten patients with intermediate or unselective proteinuria were treated
with steroids. In only one case was there a significant reduction of
proteinuria
Glomerular selective permeability to protein, dextran, and polyvinylpyrrolidone in health and disease
This thesis presents the results of six year's work on
macromolecular clearance determinations.This work is placed in context by an introductory review
of literature relating to the physiology of protein excretion.
Early concepts of the mechanisms involved in proteinuria are
discussed. Among the studies reviewed are observations on
micropuncture of the glomeruli and proximal tubules, clearance
experiments, stop-flow analyses, histochemicai findings, and
electron microscopy studies, It is concluded from this review of
the literature that some protein is filtered at the glomeruli, but
that in health virtually all of this is reabsorbed by a process
which, for albumin and molecules larger than albumin, is non-selective, Reasons are given for the opinion that tubular
secretion of protein is unimportant.The immunodiffusion method used in protein clearance studies
is then described, along with the gel filtration technique used to
determine protein, dextran, and polyvinylpyrrolidone clearances.
The errors involved in these techniques are discussed.Results are presented for protein clearance studies carried
out in parallel by the two techniques. From an analysis of these
results it is concluded that in patients excreting over 1.OG of
protein daily, -K (the index of protein selectivity by the immuno-diffusion technique) is related to Δ (the index of selectivity by
the gel filtration technique) by the formula Δ = 0.73 (-K).Dextran and protein selectivity values are compared in normal
subjects, in proteinuria induced by plasma infusion, and in a
variety of disease states. In minimal lesion glomerulonephritis,
membranous glomerulonephritis and in induced proteinuria, dextran
and protein selectivity values are in substantial agreement. In
normal subjects under normal conditions, in proliferative glomerulonephritis, in postural proteinuria, and in acute ischaemic renal
failure, dextran selectivity values are consistently and considerably higher than protein selectivity values. These findings are
explained in terms of differences in the renal handling of protein
and dextran and in terras of differences in the mechanisms involved
in proteinuria in the various conditions described. From the
experiments on induced proteinuria it is concluded that the
filtration of protein at the normal glomerulus, like that of dextran,
is highly selective.The results of protein selectivity determinations in 207
patients with major proteinuria are presented and related to the
histological diagnoses. Selectivity values in minimal lesion
glomerulonephritis are consistently high, while in patients with
renal failure proteinuria is uniformly unselective.The relationship between protein selectivity and prognosis
is assessed in 197 patients. A very high selectivity (-K over
2.6) is associated with a very good prognosis (3 year survival
with functioning kidneys of 96%). A very low selectivity (-K less
than 1.4) is associated with a poor prognosis (3 year survival of
27%).The relationship between selectivity and responsiveness to
steroid therapy is assessed in 82 treated patients. In our
experience, a selectivity value of 2.0 or less is consistently
associated with unresponsiveness to steroid therapy• While prompt
abolition of proteinuria following steroid therapy is to be
expected only in patients with minimal lesion glomerulonephritis,
comparison of the outcome at 8 weeks in 30 treated proliferatives
with findings at 8 weeks in 26 untreated controls with similar
histology shows a significant reduction in proteinuria in response
to steroids in patients with proliferative histology and selective
proteinuria
Insulin resistance in type 1 diabetes: what is ‘double diabetes’ and what are the risks?
In this review, we explore the concept of ‘double diabetes’, a combination of type 1 diabetes with features of insulin resistance and type 2 diabetes. After considering whether double diabetes is a useful concept, we discuss potential mechanisms of increased insulin resistance in type 1 diabetes before examining the extent to which double diabetes might increase the risk of cardiovascular disease (CVD). We then go on to consider the proposal that weight gain from intensive insulin regimens may be associated with increased CV risk factors in some patients with type 1 diabetes, and explore the complex relationships between weight gain, insulin resistance, glycaemic control and CV outcome. Important comparisons and contrasts between type 1 diabetes and type 2 diabetes are highlighted in terms of hepatic fat, fat partitioning and lipid profile, and how these may differ between type 1 diabetic patients with and without double diabetes. In so doing, we hope this work will stimulate much-needed research in this area and an improvement in clinical practice
Quantum state preparation and macroscopic entanglement in gravitational-wave detectors
Long-baseline laser-interferometer gravitational-wave detectors are operating
at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within
a broad frequency band. Such a low classical noise budget has already allowed
the creation of a controlled 2.7 kg macroscopic oscillator with an effective
eigenfrequency of 150 Hz and an occupation number of 200. This result, along
with the prospect for further improvements, heralds the new possibility of
experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical
behavior of objects in the realm of everyday experience - using
gravitational-wave detectors. In this paper, we provide the mathematical
foundation for the first step of a MQM experiment: the preparation of a
macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum
state, which is possible if the interferometer's classical noise beats the SQL
in a broad frequency band. Our formalism, based on Wiener filtering, allows a
straightforward conversion from the classical noise budget of a laser
interferometer, in terms of noise spectra, into the strategy for quantum state
preparation, and the quality of the prepared state. Using this formalism, we
consider how Gaussian entanglement can be built among two macroscopic test
masses, and the performance of the planned Advanced LIGO interferometers in
quantum-state preparation
Does prior coronary angioplasty affect outcomes of surgical coronary revascularization? Insights from the STICH trial
Background:
The STICH trial showed superiority of coronary artery bypass plus medical treatment (CABG) over medical treatment alone (MED) in patients with left ventricular ejection fraction (LVEF) ≤35%. In previous publications, percutaneous coronary intervention (PCI) prior to CABG was associated with worse prognosis.
Objectives:
The main purpose of this study was to analyse if prior PCI influenced outcomes in STICH.
Methods and results:
Patients in the STICH trial (n = 1212), followed for a median time of 9.8 years, were included in the present analyses. In the total population, 156 had a prior PCI (74 and 82, respectively, in the MED and CABG groups). In those with vs. without prior PCI, the adjusted hazard-ratios (aHRs) were 0.92 (95% CI = 0.74–1.15) for all-cause mortality, 0.85 (95% CI = 0.64–1.11) for CV mortality, and 1.43 (95% CI = 1.15–1.77) for CV hospitalization. In the group randomized to CABG without prior PCI, the aHRs were 0.82 (95% CI = 0.70–0.95) for all-cause mortality, 0.75 (95% CI = 0.62–0.90) for CV mortality and 0.67 (95% CI = 0.56–0.80) for CV hospitalization. In the group randomized to CABG with prior PCI, the aHRs were 0.76 (95% CI = 0.50–1.15) for all-cause mortality, 0.81 (95% CI = 0.49–1.36) for CV mortality and 0.61 (95% CI = 0.41–0.90) for CV hospitalization. There was no evidence of interaction between randomized treatment and prior PCI for any endpoint (all adjusted p > 0.05).
Conclusion:
In the STICH trial, prior PCI did not affect the outcomes of patients whether they were treated medically or surgically, and the superiority of CABG over MED remained unchanged regardless of prior PCI.
Clinical trial registration:
Clinicaltrials.gov; Identifier: NCT0002359
Episodic Occurrence of Favourable Weather Constrains Recovery of a Cold Desert Shrubland After Fire
Key to the long-term resilience of dryland ecosystems is the recovery of foundation plant species following disturbance. In ecosystems with high interannual weather variability, understanding the influence of short-term environmental conditions on establishment of foundation species is essential for identifying vulnerable landscapes and developing restoration strategies. We asked how annual environmental conditions affect post-fire establishment of Artemisia tridentata, a shrub species that dominates landscapes across much of the western United States, and evaluated the influence of episodic establishment on population recovery. We collected A. tridentata stem samples from 33 plots in 12 prescribed fire sites that burned 8–11 years before sampling. We determined individual establishment years using annual growth rings. We measured seasonal soil environmental conditions at the study sites and asked if these conditions predicted annual establishment density. We then evaluated whether establishment patterns could be predicted by site-level climate or dominant subspecies. Finally, we tested the effect of the magnitude and frequency of post-fire establishment episodes on long-term population recovery. Annual post-fire recruitment of A. tridentata was driven by the episodic availability of spring soil moisture. Annual establishment was highest with wetter spring soils (relative influence [RI] = 19.4%) and later seasonal dry-down (RI = 11.8%) in the year of establishment. Establishment density declined greatly 4 to 5 years after fire (RI = 17.1%). Post-fire establishment patterns were poorly predicted by site-level mean climate (marginal R2 ≤ 0.18) and dominant subspecies (marginal R2 ≤ 0.43). Population recovery reflected the magnitude, but not the frequency, of early post-fire establishment pulses. Post-fire A. tridentata density and cover (measured 8–11 years after fire) were more strongly related to the magnitude of the largest establishment pulse than to establishment frequency, suggesting that population recovery may occur with a single favourable establishment year. Synthesis and applications. This study demonstrates the importance of episodic periods of favourable weather for long-term plant population recovery following disturbance. Management strategies that increase opportunities for seed availability to coincide with favourable weather conditions, such as retaining unburned patches or repeated seeding treatments, can improve restoration outcomes in high-priority areas
Recommended from our members
International films and international markets: the globalisation of Hollywood entertainment, c.1921-1951
The international appeal of Hollywood films through the twentieth century has been a subject of interest to economic and film historians alike. This paper employs some of the methods of the economic historian to evaluate key arguments within the film history literature explaining the global success of American films. Through careful analysis of both existing and newly constructed data sets, the paper examines the extent to which Hollywood's foreign earnings were affected by: film production costs; the extent of global distribution networks; and also the international orientation of the films themselves. The paper finds that these factors influenced foreign earnings in quite distinct ways, and that their relative importance changed over time. The evidence presented here suggests a degree of interaction between the production and distribution arms of the major US film companies in their pursuit of foreign markets that would benefit from further archival-based investigation
A novel formulation of inhaled sodium cromoglicate (PA101) in idiopathic pulmonary fibrosis and chronic cough: a randomised, double-blind, proof-of-concept, phase 2 trial
Background Cough can be a debilitating symptom of idiopathic pulmonary fibrosis (IPF) and is difficult to treat. PA101 is a novel formulation of sodium cromoglicate delivered via a high-efficiency eFlow nebuliser that achieves significantly higher drug deposition in the lung compared with the existing formulations. We aimed to test the efficacy and safety of inhaled PA101 in patients with IPF and chronic cough and, to explore the antitussive mechanism of PA101, patients with chronic idiopathic cough (CIC) were also studied. Methods This pilot, proof-of-concept study consisted of a randomised, double-blind, placebo-controlled trial in patients with IPF and chronic cough and a parallel study of similar design in patients with CIC. Participants with IPF and chronic cough recruited from seven centres in the UK and the Netherlands were randomly assigned (1:1, using a computer-generated randomisation schedule) by site staff to receive PA101 (40 mg) or matching placebo three times a day via oral inhalation for 2 weeks, followed by a 2 week washout, and then crossed over to the other arm. Study participants, investigators, study staff, and the sponsor were masked to group assignment until all participants had completed the study. The primary efficacy endpoint was change from baseline in objective daytime cough frequency (from 24 h acoustic recording, Leicester Cough Monitor). The primary efficacy analysis included all participants who received at least one dose of study drug and had at least one post-baseline efficacy measurement. Safety analysis included all those who took at least one dose of study drug. In the second cohort, participants with CIC were randomly assigned in a study across four centres with similar design and endpoints. The study was registered with ClinicalTrials.gov (NCT02412020) and the EU Clinical Trials Register (EudraCT Number 2014-004025-40) and both cohorts are closed to new participants. Findings Between Feb 13, 2015, and Feb 2, 2016, 24 participants with IPF were randomly assigned to treatment groups. 28 participants with CIC were enrolled during the same period and 27 received study treatment. In patients with IPF, PA101 reduced daytime cough frequency by 31·1% at day 14 compared with placebo; daytime cough frequency decreased from a mean 55 (SD 55) coughs per h at baseline to 39 (29) coughs per h at day 14 following treatment with PA101, versus 51 (37) coughs per h at baseline to 52 (40) cough per h following placebo treatment (ratio of least-squares [LS] means 0·67, 95% CI 0·48–0·94, p=0·0241). By contrast, no treatment benefit for PA101 was observed in the CIC cohort; mean reduction of daytime cough frequency at day 14 for PA101 adjusted for placebo was 6·2% (ratio of LS means 1·27, 0·78–2·06, p=0·31). PA101 was well tolerated in both cohorts. The incidence of adverse events was similar between PA101 and placebo treatments, most adverse events were mild in severity, and no severe adverse events or serious adverse events were reported. Interpretation This study suggests that the mechanism of cough in IPF might be disease specific. Inhaled PA101 could be a treatment option for chronic cough in patients with IPF and warrants further investigation
Determinants of recovery from post-COVID-19 dyspnoea: analysis of UK prospective cohorts of hospitalised COVID-19 patients and community-based controls
Background The risk factors for recovery from COVID-19 dyspnoea are poorly understood. We investigated determinants of recovery from dyspnoea in adults with COVID-19 and compared these to determinants of recovery from non-COVID-19 dyspnoea. Methods We used data from two prospective cohort studies: PHOSP-COVID (patients hospitalised between March 2020 and April 2021 with COVID-19) and COVIDENCE UK (community cohort studied over the same time period). PHOSP-COVID data were collected during hospitalisation and at 5-month and 1-year follow-up visits. COVIDENCE UK data were obtained through baseline and monthly online questionnaires. Dyspnoea was measured in both cohorts with the Medical Research Council Dyspnoea Scale. We used multivariable logistic regression to identify determinants associated with a reduction in dyspnoea between 5-month and 1-year follow-up. Findings We included 990 PHOSP-COVID and 3309 COVIDENCE UK participants. We observed higher odds of improvement between 5-month and 1-year follow-up among PHOSP-COVID participants who were younger (odds ratio 1.02 per year, 95% CI 1.01–1.03), male (1.54, 1.16–2.04), neither obese nor severely obese (1.82, 1.06–3.13 and 4.19, 2.14–8.19, respectively), had no pre-existing anxiety or depression (1.56, 1.09–2.22) or cardiovascular disease (1.33, 1.00–1.79), and shorter hospital admission (1.01 per day, 1.00–1.02). Similar associations were found in those recovering from non-COVID-19 dyspnoea, excluding age (and length of hospital admission). Interpretation Factors associated with dyspnoea recovery at 1-year post-discharge among patients hospitalised with COVID-19 were similar to those among community controls without COVID-19. Funding PHOSP-COVID is supported by a grant from the MRC-UK Research and Innovation and the Department of Health and Social Care through the National Institute for Health Research (NIHR) rapid response panel to tackle COVID-19. The views expressed in the publication are those of the author(s) and not necessarily those of the National Health Service (NHS), the NIHR or the Department of Health and Social Care. COVIDENCE UK is supported by the UK Research and Innovation, the National Institute for Health Research, and Barts Charity. The views expressed are those of the authors and not necessarily those of the funders
- …