A sustainable vision for general practice: Addressing the challenges

BACKGROUND

The systemic problems and challenges of general practice within the health system require systemic solutions.

OBJECTIVE

Noting the complex adaptive nature of health, illness and disease, and its distribution within communities and general practice work, this article suggests a model for general practice that allows the full scope of practice to be developed while creating seamlessly integrated general practice colleges that support general practitioners on their journey to 'mastery' in their chosen discipline.

DISCUSSION

The authors discuss the complex dynamics underpinning knowledge and skills development throughout doctors' careers, and the need for policy makers to evaluate health improvement and resourcing based on their interdependencies with all societal activity. To succeed, the profession would have to adopt the principles that form the foundation of generalism and complex adaptive organisations to strengthen its ability to successfully interact with all its stakeholders.

A sustainable vision for general practice: Understanding the challenges

BACKGROUND

The COVID-19 pandemic has revealed the full extent of the crisis in general practice, which has emerged as nothing more than the tip of the iceberg of a health system in crisis.

OBJECTIVE

This article introduces the systems and complexity thinking that frame the problems affecting general practice and the systemic challenges inherent in redesigning it.

DISCUSSION

The authors show how embedded general practice is in the overall complex adaptive organisation of the health system. They allude to some of the key concerns that need to be dissolved in its redesign to achieve an effective, efficient, equitable and sustainable general practice system within a redesigned overall health system to achieve the best possible desired health experiences for patients.

Characterisation of thymol effects on RDL receptors from the bee parasite Varroa destructor

A major contributor to bee colony decline is infestation with its most devastating pest, the mite Varroa destructor. To control these mites, thymol is often used, although how it achieves this is not understood. One well-documented action of thymol is to modulate GABA-activated ion channels, which includes insect RDL receptors, a known insecticidal target. Here we have cloned two Varroa RDL subunits, one of which is similar to the canonical RDL subunit, while the other has some differences in M4, and, to a lesser extent, M2 and its binding site loops. Expression of this unusual RDL receptor in Xenopus oocytes reveals GABA-activated receptors, with an EC50 of 56 μM. In contrast to canonical RDL receptors, thymol does not enhance GABA-elicited responses in this receptor, and concentration response curves reveal a decrease in GABA Imax in its presence; this decrease is not seen when similar data are obtained from Apis RDL receptors. We conclude that an M2 T6'M substitution is primarily responsible for the different thymol effects, and suggest that understanding how and where thymol acts could assist in the design of novel bee-friendly miticides.

Innovative clinical trial design and delivery: a phase 3 COVID-19 post-exposure prophylaxis study in skilled nursing and assisted living facilities (BLAZE-2)

The efficient community spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the current pandemic of coronavirus disease-2019 (COVID-19), which in severe and critical cases results in progressive pulmonary infection, complicated by respiratory failure, with a high prevalence of acute respiratory distress syndrome. Of all age groups, older adults have the greatest risk of severe COVID-19 and the associated complications. Globally, there are many reports of the rapid spread of COVID-19 among residents of skilled nursing facilities, with high associated rates of morbidity and mortality. With over 1.3 million residents in nursing home care in the USA, there is an urgent need for therapeutic strategies to prevent COVID-19 in these populations.

Lilly, in collaboration with the National Institute of Allergy and Infectious Diseases, conducted the BLAZE-2 trial to evaluate the efficacy and safety of the monoclonal antibody bamlanivimab (LY3819253) in preventing SARS-CoV-2 infection and COVID-19, defined as symptomatic infection, in skilled nursing and assisted living facilities. It is a phase 3 randomized, double-blind, placebo-controlled trial, where participants were randomized to bamlanivimab (4200 mg) or placebo and then followed up for 24 weeks. Conducting a trial in the midst of a pandemic in these facilities poses several challenges, including a vulnerable elderly population, travel restrictions, supply chain interruptions, and defining the target population. The operational challenges were addressed by the innovative use of mobile research units which are customized, equipped, and staffed to support BLAZE-2 randomization and participant dosing within the skilled nursing and assisted living facilities. Herein, we describe the design of the study, the analytics behind facility selection, and an innovative operational model.

Effect of Bamlanivimab vs Placebo on Incidence of COVID-19 Among Residents and Staff of Skilled Nursing and Assisted Living Facilities: A Randomized Clinical Trial

IMPORTANCE

Preventive interventions are needed to protect residents and staff of skilled nursing and assisted living facilities from COVID-19 during outbreaks in their facilities. Bamlanivimab, a neutralizing monoclonal antibody against SARS-CoV-2, may confer rapid protection from SARS-CoV-2 infection and COVID-19.

OBJECTIVE

To determine the effect of bamlanivimab on the incidence of COVID-19 among residents and staff of skilled nursing and assisted living facilities.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, single-dose, phase 3 trial that enrolled residents and staff of 74 skilled nursing and assisted living facilities in the United States with at least 1 confirmed SARS-CoV-2 index case. A total of 1175 participants enrolled in the study from August 2 to November 20, 2020. Database lock was triggered on January 13, 2021, when all participants reached study day 57.

INTERVENTIONS

Participants were randomized to receive a single intravenous infusion of bamlanivimab, 4200 mg (n = 588), or placebo (n = 587).

MAIN OUTCOMES AND MEASURES

The primary outcome was incidence of COVID-19, defined as the detection of SARS-CoV-2 by reverse transcriptase-polymerase chain reaction and mild or worse disease severity within 21 days of detection, within 8 weeks of randomization. Key secondary outcomes included incidence of moderate or worse COVID-19 severity and incidence of SARS-CoV-2 infection.

RESULTS

The prevention population comprised a total of 966 participants (666 staff and 300 residents) who were negative at baseline for SARS-CoV-2 infection and serology (mean age, 53.0 [range, 18-104] years; 722 [74.7%] women). Bamlanivimab significantly reduced the incidence of COVID-19 in the prevention population compared with placebo (8.5% vs 15.2%; odds ratio, 0.43 [95% CI, 0.28-0.68]; P < .001; absolute risk difference, -6.6 [95% CI, -10.7 to -2.6] percentage points). Five deaths attributed to COVID-19 were reported by day 57; all occurred in the placebo group. Among 1175 participants who received study product (safety population), the rate of participants with adverse events was 20.1% in the bamlanivimab group and 18.9% in the placebo group. The most common adverse events were urinary tract infection (reported by 12 participants [2%] who received bamlanivimab and 14 [2.4%] who received placebo) and hypertension (reported by 7 participants [1.2%] who received bamlanivimab and 10 [1.7%] who received placebo).

CONCLUSIONS AND RELEVANCE

Among residents and staff in skilled nursing and assisted living facilities, treatment during August-November 2020 with bamlanivimab monotherapy reduced the incidence of COVID-19 infection. Further research is needed to assess preventive efficacy with current patterns of viral strains with combination monoclonal antibody therapy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04497987.

Free 25-hydroxyvitamin-D concentrations are lower in children with renal transplant compared with chronic kidney disease

BACKGROUND

Total serum 25-hydroxyvitamin D [25(OH)D] is considered the best marker of vitamin D status and used routinely in clinical practice. However, 25(OH)D is predominantly bound to vitamin D-binding protein (VDBP), and it has been reported that the free-25(OH)D and 25(OH)D loosely bound to albumin fraction correlates better with clinical outcomes.

METHODS

We assessed total-25(OH)D, measured free-25(OH)D, and calculated free-25(OH)D and their relationship with VDBP and biomarkers of mineral metabolism in 61 children (22 CKD 2-3, 18 dialysis, and 21 post-transplant).

RESULTS

Total-25(OH)D concentrations were comparable across the three groups (p = 0.09), but free- and bioavailable-25(OH)D (free- and albumin-25(OH)D) were significantly lower in the transplant group (both: p = 0.01). Compared to CKD and dialysis patients, the transplant group had significantly higher VDBP concentrations (p = 0.03). In all three groups, total-25(OH)D concentrations were positively associated with measured free-, calculated free-, and bioavailable-25(OH)D. Multivariable regression analysis showed that total-25(OH)D was the only predictor of measured free-25(OH)D concentrations in the dialysis group (β = 0.9; R² = 90%). In the transplant group, measured free-25(OH)D concentrations were predicted by both total-25(OH)D and VDBP concentrations (β = 0.6, - 0.6, respectively; R² = 80%). Correlations between parathyroid hormone with total-25(OH)D and measured and calculated free-25(OH)D were only observed in the transplant group (all: p < 0.001).

CONCLUSIONS

In transplanted patients, VDBP concentrations were significantly higher compared to CKD and dialysis patients, and consequently, free-25(OH)D concentrations were lower, despite a comparable total-25(OH)D concentration. We suggest that free-25(OH)D measures may be required in children with CKD, dialysis, and transplant, with further research required to understand its association with markers of mineral metabolism.

Spatiotemporal dynamics and heterogeneity of renal lymphatics in mammalian development and cystic kidney disease

Heterogeneity of lymphatic vessels during embryogenesis is critical for organ-specific lymphatic function. Little is known about lymphatics in the developing kidney, despite their established roles in pathology of the mature organ. We performed three-dimensional imaging to characterize lymphatic vessel formation in the mammalian embryonic kidney at single-cell resolution. In mouse, we visually and quantitatively assessed the development of kidney lymphatic vessels, remodeling from a ring-like anastomosis under the nascent renal pelvis; a site of VEGF-C expression, to form a patent vascular plexus. We identified a heterogenous population of lymphatic endothelial cell clusters in mouse and human embryonic kidneys. Exogenous VEGF-C expanded the lymphatic population in explanted mouse embryonic kidneys. Finally, we characterized complex kidney lymphatic abnormalities in a genetic mouse model of polycystic kidney disease. Our study provides novel insights into the development of kidney lymphatic vasculature; a system which likely has fundamental roles in renal development, physiology and disease.

In most organs in the body, fluid tends to build up in the spaces between cells, especially if the organs become inflamed. Each organ has a ‘waste disposal system’; a set of specialized tubes called lymphatic vessels, to clear away this excess fluid and keep a check on inflammation. Defects in these tubes have been linked to a wide range of diseases including heart attacks, obesity, dementia and cancer.

The kidneys are responsible for filtering blood and balancing many of the body’s chemical processes. Polycystic kidney disease (PKD) is the most common genetic kidney disorder and it results in cysts filled with fluid building up in the kidney. The growth of cysts in PKD may be due to a problem with the lymphatic vessels. However, compared to other organs, how lymphatic vessels first form within the kidney and what they do is not well understood.

Now, Jafree et al. have used three-dimensional imaging to study how lymphatic vessels form in the kidneys of mice and humans. The experiments showed that lymphatic vessels first appear when mouse kidneys are about half developed, and start to grow rapidly when the kidneys are thought to begin filtering blood. Clusters of cells that may help lymphatic vessels to grow were also found hidden deep within the kidneys of mouse embryos. Treating the kidneys with a factor that stimulates the growth of lymphatic vessels increased the numbers of these clusters. Jafree et al. found similar clusters of cells in human kidneys, suggesting that lymphatic vessels in the kidneys of different mammals may develop in the same way.

Further experiments showed that the lymphatic vessels of kidneys in mice with PKD become distorted early on in the disease, when cysts are still small and before the mice develop symptoms. In the future, identifying drugs that target kidney lymphatic vessels may lead to more effective treatments for patients with PKD and other kidney diseases.

Vangl2, a planar cell polarity molecule, is implicated in irreversible and reversible kidney glomerular injury

Planar cell polarity (PCP) pathways control the orientation and alignment of epithelial cells within tissues. Van Gogh-like 2 (Vangl2) is a key PCP protein that is required for the normal differentiation of kidney glomeruli and tubules. Vangl2 has also been implicated in modifying the course of acquired glomerular disease, and here, we further explored how Vangl2 impacts on glomerular pathobiology in this context. Targeted genetic deletion of Vangl2 in mouse glomerular epithelial podocytes enhanced the severity of not only irreversible accelerated nephrotoxic nephritis but also lipopolysaccharide-induced reversible glomerular damage. In each proteinuric model, genetic deletion of Vangl2 in podocytes was associated with an increased ratio of active-MMP9 to inactive MMP9, an enzyme involved in tissue remodelling. In addition, by interrogating microarray data from two cohorts of renal patients, we report increased VANGL2 transcript levels in the glomeruli of individuals with focal segmental glomerulosclerosis, suggesting that the molecule may also be involved in certain human glomerular diseases. These observations support the conclusion that Vangl2 modulates glomerular injury, at least in part by acting as a brake on MMP9, a potentially harmful endogenous enzyme. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Vascular Endothelial Growth Factor C for Polycystic Kidney Diseases

Polycystic kidney diseases (PKD) are genetic disorders characterized by progressive epithelial cyst growth leading to destruction of normally functioning renal tissue. Current therapies have focused on the cyst epithelium, and little is known about how the blood and lymphatic microvasculature modulates cystogenesis. Hypomorphic Pkd1(nl/nl) mice were examined, showing that cystogenesis was associated with a disorganized pericystic network of vessels expressing platelet/endothelial cell adhesion molecule 1 and vascular endothelial growth factor receptor 3 (VEGFR3). The major ligand for VEGFR3 is VEGFC, and there were lower levels of Vegfc mRNA within the kidneys during the early stages of cystogenesis in 7-day-old Pkd1(nl/nl) mice. Seven-day-old mice were treated with exogenous VEGFC for 2 weeks on the premise that this would remodel both the VEGFR3(+) pericystic vascular network and larger renal lymphatics that may also affect the severity of PKD. Treatment with VEGFC enhanced VEGFR3 phosphorylation in the kidney, normalized the pattern of the pericystic network of vessels, and widened the large lymphatics in Pkd1(nl/nl) mice. These effects were associated with significant reductions in cystic disease, BUN and serum creatinine levels. Furthermore, VEGFC administration reduced M2 macrophage pericystic infiltrate, which has been implicated in the progression of PKD. VEGFC administration also improved cystic disease in Cys1(cpk/cpk) mice, a model of autosomal recessive PKD, leading to a modest but significant increase in lifespan. Overall, this study highlights VEGFC as a potential new treatment for some aspects of PKD, with the possibility for synergy with current epithelially targeted approaches.

Genetic Background is a Key Determinant of Glomerular Extracellular Matrix Composition and Organization

Glomerular disease often features altered histologic patterns of extracellular matrix (ECM). Despite this, the potential complexities of the glomerular ECM in both health and disease are poorly understood. To explore whether genetic background and sex determine glomerular ECM composition, we investigated two mouse strains, FVB and B6, using RNA microarrays of isolated glomeruli combined with proteomic glomerular ECM analyses. These studies, undertaken in healthy young adult animals, revealed unique strain- and sex-dependent glomerular ECM signatures, which correlated with variations in levels of albuminuria and known predisposition to progressive nephropathy. Among the variation, we observed changes in netrin 4, fibroblast growth factor 2, tenascin C, collagen 1, meprin 1-α, and meprin 1-β. Differences in protein abundance were validated by quantitative immunohistochemistry and Western blot analysis, and the collective differences were not explained by mutations in known ECM or glomerular disease genes. Within the distinct signatures, we discovered a core set of structural ECM proteins that form multiple protein-protein interactions and are conserved from mouse to man. Furthermore, we found striking ultrastructural changes in glomerular basement membranes in FVB mice. Pathway analysis of merged transcriptomic and proteomic datasets identified potential ECM regulatory pathways involving inhibition of matrix metalloproteases, liver X receptor/retinoid X receptor, nuclear factor erythroid 2-related factor 2, notch, and cyclin-dependent kinase 5. These pathways may therefore alter ECM and confer susceptibility to disease.

Comparison of Bayesian and frequentist meta-analytical approaches for analyzing time to event data

Using meta-analysis in health care research is a common practice. Here we are interested in methods used for analysis of time-to-event data. Particularly, we are interested in their performance when there is a low event rate. We consider three methods based on the Cox proportional hazards model, including a Bayesian approach. A formal comparison of the methods is conducted using a simulation study. In our simulation we model two treatments and consider several scenarios.

Targeted glomerular angiopoietin-1 therapy for early diabetic kidney disease

Vascular growth factors play an important role in maintaining the structure and integrity of the glomerular filtration barrier. In healthy adult glomeruli, the proendothelial survival factors vascular endothelial growth factor-A (VEGF-A) and angiopoietin-1 are constitutively expressed in glomerular podocyte epithelia. We demonstrate that this milieu of vascular growth factors is altered in streptozotocin-induced type 1 diabetic mice, with decreased angiopoietin-1 levels, VEGF-A upregulation, decreased soluble VEGF receptor-1 (VEGFR1), and increased VEGFR2 phosphorylation. This was accompanied by marked albuminuria, nephromegaly, hyperfiltration, glomerular ultrastructural alterations, and aberrant angiogenesis. We subsequently hypothesized that restoration of angiopoietin-1 expression within glomeruli might ameliorate manifestations of early diabetic glomerulopathy. Podocyte-specific inducible repletion of angiopoietin-1 in diabetic mice caused a 70% reduction of albuminuria and prevented diabetes-induced glomerular endothelial cell proliferation; hyperfiltration and renal morphology were unchanged. Furthermore, angiopoietin-1 repletion in diabetic mice increased Tie-2 phosphorylation, elevated soluble VEGFR1, and was paralleled by a decrease in VEGFR2 phosphorylation and increased endothelial nitric oxide synthase Ser(1177) phosphorylation. Diabetes-induced nephrin phosphorylation was also reduced in mice with angiopoietin-1 repletion. In conclusion, targeted angiopoietin-1 therapy shows promise as a renoprotective tool in the early stages of diabetic kidney disease.

Guidance on the implementation and reporting of a drug safety Bayesian network meta-analysis

The Drug Information Association Bayesian Scientific Working Group (BSWG) was formed in 2011 with a vision to ensure that Bayesian methods are well understood and broadly utilized for design and analysis and throughout the medical product development process, and to improve industrial, regulatory, and economic decision making. The group, composed of individuals from academia, industry, and regulatory, has as its mission to facilitate the appropriate use and contribute to the progress of Bayesian methodology. In this paper, the safety sub-team of the BSWG explores the use of Bayesian methods when applied to drug safety meta-analysis and network meta-analysis. Guidance is presented on the conduct and reporting of such analyses. We also discuss different structural model assumptions and provide discussion on prior specification. The work is illustrated through a case study involving a network meta-analysis related to the cardiovascular safety of non-steroidal anti-inflammatory drugs.

Bayesian methods for design and analysis of safety trials

Safety assessment is essential throughout medical product development. There has been increased awareness of the importance of safety trials recently, in part due to recent US Food and Drug Administration guidance related to thorough assessment of cardiovascular risk in the treatment of type 2 diabetes. Bayesian methods provide great promise for improving the conduct of safety trials. In this paper, the safety subteam of the Drug Information Association Bayesian Scientific Working Group evaluates challenges associated with current methods for designing and analyzing safety trials and provides an overview of several suggested Bayesian opportunities that may increase efficiency of safety trials along with relevant case examples.

Circulating angiopoietin-2 is a marker for early cardiovascular disease in children on chronic dialysis

Cardiovascular disease (CVD) is increasingly recognised as a complication of childhood chronic kidney disease (CKD) even in the absence of diabetes and hypertension. We hypothesized that an alteration in angiopoietin-1 and -2, growth factors which regulate endothelial and vascular function could be involved. We report that the endothelial survival factor, angiopoietin-1 is low in children with pre-dialysis CKD whereas the pro-inflammatory angiopoietin-2 is elevated in children on dialysis. In dialysis patients, angiopoietin-2 positively correlated with time on dialysis, systolic blood pressure, and carotid artery intima media thickness. Elevated angiopoietin-2 levels in dialysis versus pre-dialysis CKD patients were also associated with an anti-angiogenic (high soluble VEGFR-1 and low VEGF-A) and pro-inflammatory (high urate, E-selectin, P-selectin and VCAM-1) milieu. Ang-2 was immunodetected in arterial biopsy samples whilst the expression of VEGF-A was significantly downregulated in dialysis patients. Serum urate correlated with angiopoietin-2 levels in dialysis patients and addition of uric acid was able to induce rapid release of angiopoietin-2 from cultured endothelial cells. Thus, angiopoietin-2 is a marker for cardiovascular disease in children on chronic dialysis and may act as an anti-angiogenic and pro-inflammatory effector in this context. The possibility that the release of angiopoietin-2 from endothelia is mediated by urate should be explored further.

Diet physical form, fatty acid chain length, and emulsification alter fat utilization and growth of newly weaned pigs

An experiment was conducted to examine the interplay of diet physical form (liquid vs. dry), fatty acid chain length [medium- (MCT) vs. long-chain triglyceride (LCT)], and emulsification as determinants of fat utilization and growth of newly weaned pigs. Ninety-six pigs were weaned at 20.0 ± 0.3 d of age (6.80 ± 0.04 kg) and fed ad libitum 1 of 8 diets for 14 d according to a 2(3) factorial arrangement of treatments with 6 pens per diet and 2 pigs per pen. The MCT contained primarily C8:0 and C10:0 fatty acids, whereas the LCT mainly contained C16:0, C18:0, C18:1, and C18:2. Diet physical form greatly impacted piglet growth (P < 0.001), with liquid-fed pigs (486 g/d) growing faster than dry-fed pigs (332 g/d) by 46%. Pigs fed LCT grew 22% faster (P = 0.01) than MCT-fed pigs; however, effects of emulsifier were not detected (P > 0.1). Furthermore, feed intake and G:F were 15% and 29% greater for liquid-fed pigs, and intake also was 21% greater for pigs fed LCT (P = 0.01). Diet physical form had no effect on apparent ileal fatty acid digestibility, but as expected, digestibility was greater (P < 0.001) for the MCT than the LCT diet (98.5% vs. 93.4%). Emulsification improved digestibility of most fatty acids in pigs fed LCT but not MCT (interaction, P < 0.01). Both jejunal and ileal villi height increased from 7 to 14 d postweaning (P < 0.01). Liquid-fed pigs had greater jejunal crypt depth (P < 0.05) compared with pigs fed the dry diet; however, ileal morphology was not affected by diet physical form, fat chain length, or emulsification. Plasma ketone body concentrations were 6-fold greater in pigs fed MCT than LCT, and the difference was greater in pigs fed dry diets (interaction, P = 0.01). The bile salt concentration in jejunal digesta was 2.2-fold greater in pigs fed LCT than in pigs fed MCT (P < 0.001). Collectively, we conclude that feeding liquid diets containing emulsified LCT can improve fat utilization and markedly accentuate feed intake, growth, and G:F of weanling pigs.

The impact of clinical and demographic variables on cognitive performance in methamphetamine-dependent individuals in rural South Carolina

Inconsistencies in reports on methamphetamine (METH) associated cognitive dysfunction may be attributed, at least in part, to the diversity of study sample features (eg, clinical and demographic characteristics). The current study assessed cognitive function in a METH-dependent population from rural South Carolina, and the impact of demographic and clinical characteristics on performance. Seventy-one male (28.2%) and female (71.8%) METH-dependent subjects were administered a battery of neurocognitive tests including the Test of Memory Malingering (TOMM), Shipley Institute of Living Scale, Paced Auditory Serial Addition Test (PASAT), Symbol Digit Modalities Test (SDMT), Grooved Pegboard Test, California Verbal Learning Test (CVLT), and Wisconsin Card Sorting Test (WCST). Demographic and clinical characteristics (eg, gender, frequency of METH use) were examined as predictors of performance. Subjects scored significantly lower than expected on one test of attention and one of fine motor function, but performed adequately on all other tests. There were no predictors of performance on attention; however, more frequent METH use was associated with better performance for males and worse for females on fine motor skills. The METH-dependent individuals in this population exhibit very limited cognitive impairment. The marked differences in education, Intellectual Quotient (IQ), and gender in our sample when compared to the published literature may contribute to these findings. Characterization of the impact of clinical and/or demographic features on cognitive deficits could be important in guiding the development of treatment interventions.

Cysteine modification reveals which subunits form the ligand binding site in human heteromeric 5-HT3AB receptors

The ligand binding site of Cys-loop receptors is formed by residues on the principal (+) and complementary (-) faces of adjacent subunits, but the subunits that constitute the binding pocket in many heteromeric receptors are not yet clear. To probe the subunits involved in ligand binding in heteromeric human 5-HT(3)AB receptors, we made cysteine substitutions to the + and - faces of A and B subunits, and measured their functional consequences in receptors expressed in Xenopus oocytes. All A subunit mutations altered or eliminated function. The same pattern of changes was seen at homomeric and heteromeric receptors containing cysteine substitutions at A(R92) (- face), A(L126)(+), A(N128)(+), A(I139)(-), A(Q151)(-) and A(T181)(+), and these receptors displayed further changes when the sulphydryl modifying reagent methanethiosulfonate-ethylammonium (MTSEA) was applied. Modifications of A(R92C)(-)- and A(T181C)(+)-containing receptors were protected by the presence of agonist (5-HT) or antagonist (d-tubocurarine). In contrast modifications of the equivalent B subunit residues did not alter heteromeric receptor function. In addition a double mutant, A(S206C)(-)(/E229C)(+), only responded to 5-HT following DTT treatment in both homomeric and heteromeric receptors, indicating receptor function was inhibited by a disulphide bond between an A+ and an A- interface in both receptor types. Our results are consistent with binding to an A+A- interface at both homomeric and heteromeric human 5-HT(3) receptors, and explain why the competitive pharmacologies of these two receptors are identical.

Modified citrus pectin reduces galectin-3 expression and disease severity in experimental acute kidney injury

Galectin-3 is a β-galactoside binding lectin with roles in diverse processes including proliferation, apoptosis, inflammation and fibrosis which are dependent on different domains of the molecule and subcellular distribution. Although galectin-3 is known to be upregulated in acute kidney injury, the relative importance of its different domains and functions are poorly understood in the underlying pathogenesis. Therefore we experimentally modulated galectin-3 in folic acid (FA)-induced acute kidney injury utilising modified citrus pectin (MCP), a derivative of pectin which can bind to the galectin-3 carbohydrate recognition domain thereby predominantly antagonising functions linked to this role. Mice were pre-treated with normal or 1% MCP-supplemented drinking water one week before FA injection. During the initial injury phase, all FA-treated mice lost weight whilst their kidneys enlarged secondary to the renal insult; these gross changes were significantly lessened in the MCP group but this was not associated with significant changes in galectin-3 expression. At a histological level, MCP clearly reduced renal cell proliferation but did not affect apoptosis. Later, during the recovery phase at two weeks, MCP-treated mice demonstrated reduced galectin-3 in association with decreased renal fibrosis, macrophages, pro-inflammatory cytokine expression and apoptosis. Other renal galectins, galectin-1 and -9, were unchanged. Our data indicates that MCP is protective in experimental nephropathy with modulation of early proliferation and later galectin-3 expression, apoptosis and fibrosis. This raises the possibility that MCP may be a novel strategy to reduce renal injury in the long term, perhaps via carbohydrate binding-related functions of galectin-3.

Use of Saccharomyces cerevisiae fermentation product on growth performance and microbiota of weaned pigs during Salmonella infection

Anaerobically fermented yeast products are a rich source of nutritional metabolites, mannanoligosaccharides, and β-glucans that may optimize gut health and immunity, which can translate into better growth performance and a reduced risk of foodborne pathogens. The objective of this study was to quantify the effects of Saccharomyces cerevisiae fermentation product (Diamond V Original XPC) inclusion in nursery diets on pig performance and gastrointestinal microbial ecology before, during, and after an oral challenge with Salmonella. Pigs (n = 40) were weaned at 21 d of age, blocked by BW, and assigned in a 2 × 2 factorial arrangement consisting of diet (control or 0.2% XPC) and inoculation (sterile broth or Salmonella). Pigs were fed a 3-phase nursery diet (0 to 7 d, 7 to 21 d, and 21 to 35 d) with ad libitum access to water and feed. On d 14, pigs were orally inoculated with 10(9) cfu of Salmonella enterica serovar Typhimurium DT104 or sterile broth. During d 17 to 20, all pigs were treated with a 5 mg/kg of BW intramuscular injection of ceftiofur-HCl. Growth performance and alterations in the gastrointestinal microbial ecology were measured during preinoculation (PRE; 0 to 14 d), sick (SCK; 14 to 21 d), and postinoculation (POST; 21 to 35 d). Body weight and ADG were measured weekly. Rectal temperature (RT) was measured weekly during PRE and POST, and every 12 h during SCK. Diet had no effect on BW, ADG, or RT during any period (P = 0.12 to 0.95). Inclusion of XPC tended (P < 0.10) to increase Salmonella shedding in feces during SCK. Consumption of XPC altered the composition of the gastrointestinal microbial community, resulting in increased (P < 0.05) populations of Bacteroidetes and Lactobacillus after Salmonella infection. Pigs inoculated with Salmonella had decreased ADG and BW, and increased RT during SCK (P < 0.001). Furthermore, fecal Salmonella cfu (log(10)) was modestly correlated (P = 0.002) with BW (r = -0.22), ADFI (r = -0.27), ADG (r = -0.36), G:F (r = -0.18), and RT (r = 0.52) during SCK. After antibiotic administration, all Salmonella-infected pigs stopped shedding. During POST, an interaction between diet and inoculation (P = 0.009) on ADG indicated that pigs infected with Salmonella grew better when eating XPC than the control diet. The addition of XPC to the diets of weanling pigs resulted in greater compensatory BW gains after infection with Salmonella than in pigs fed conventional nursery diets. This increase in BW gain is likely associated with an increase in beneficial bacteria within the gastrointestinal tract.

Corticosteroid-induced kidney dysmorphogenesis is associated with deregulated expression of known cystogenic molecules, as well as Indian hedgehog

An intact genome is essential for kidney growth and differentiation, but less is known about whether, and how, an altered fetal milieu modifies these processes. Maternal low-protein diets perturb growth of the metanephros, the precursor of the mature kidney. Fetal corticosteroid overexposure may, in part, mediate this, because such diets downregulate placental 11beta-hydroxysteroid dehydrogenase-2, which degrades maternal corticosteroids. We report that glucocorticoid and mineralocorticoid receptors are expressed in mouse metanephric epithelia. Metanephroi maintained in organ culture with hydrocortisone (1.4 or 14 microM) underwent a dose-dependant deceleration of overall growth accompanied by cyst formation. Dexamethasone, a glucocorticoid, reproduced these outcomes, but aldosterone, a mineralocorticoid, did not. Hydrocortisone upregulated transcripts levels of cadherin-11 and downregulated prospero-related homeobox-1, hence mimicking reported effects of maternal low-protein diet. Hydrocortisone also upregulated transcripts encoding Na(+)-K(+)-ATPase subunits and ligands for the epidermal growth factor receptor, all previously implicated in renal cyst growth. The most upregulated transcript, however, was indian hedgehog, and the encoded protein was immunodetected in metanephric cysts. Furthermore, in the presence of hydrocortisone, cystogenesis, but not whole organ growth, was significantly reduced by cyclopamine, a drug downregulating hedgehog signaling. Finally, both glucocorticoid receptor and indian hedgehog proteins were detected by immunohistochemistry in cystic tubules within human dysplastic kidneys, consistent with the hypothesis that these molecules modify the severity of this congenital malformation. Collectively, our observations raise the possibility that enhanced hedgehog signaling is an important stimulus for renal cyst formation. Furthermore, pharmacological inhibition of this pathway should be explored as a potential therapy for renal cystic diseases, starting with relevant animal models.

Sphingosine kinase-1: a potential mediator of renal fibrosis

Renal fibrosis contributes to glomerulosclerosis and tubulointerstitial damage in chronic kidney disease. A well-established pathway implicated in the progression of fibrosis is the induction of connective tissue growth factor by transforming growth factor-beta, resulting in the accumulation of extracellular matrix proteins. Ren and colleagues demonstrate that sphingosine kinase-1 is involved in the regulation of this pathway in the glomerulus. This raises the possibility of targeting sphingosine kinase-1 to prevent fibrosis in chronic kidney disease patients.

Unraveling the genetic landscape of bladder development in mice

PURPOSE

To better understand the pathobiology of human congenital bladder abnormalities and disorders associated with dedifferentiation, such as bladder cancer, we must first unravel the biology of normal bladder development. Therefore, we performed microarray analysis focusing on determining the gene expression profile at the initiation of bladder development.

MATERIALS AND METHODS

RNA was extracted from embryonic day 13 and 18 mouse bladders (anatomically equivalent to 7 and 13 weeks of human gestation) and gene expression was evaluated using microarrays. Alterations in select genes of biological interest were confirmed using real-time quantitative polymerase chain reaction and localization was determined by immunohistochemistry.

RESULTS

The genetic profile in the initiating mouse bladder at embryonic day 13 was dominated by transcription factors, retinoic acid signaling genes, Eph/ephrin bidirectional signaling molecules and genes associated with regulating cell cycle and differentiation. Later in development at embryonic day 18 genes associated with smooth muscle, innervation and epithelial differentiation were up-regulated. In addition, we examined the functional role of midkine, which was highly expressed at embryonic day 13, using organ culture and to our knowledge we provide the first evidence that this growth factor up-regulates molecules associated with bladder smooth muscle differentiation.

CONCLUSIONS

These data provide novel insights into molecules that orchestrate bladder development and highlight genes that may be involved in diseases associated with abnormal differentiation.

Primary cultures of renal proximal tubule cells derived from individuals with primary hyperoxaluria

The primary hyperoxalurias, PH1 and PH2, are inherited disorders caused by deficiencies of alanine:glyoxylate aminotransferase and glyoxylate reductase, respectively. Mutations in either of these enzymes leads to endogenous oxalate overproduction primarily in the liver, but most pathological effects are exhibited in the kidney ultimately leading to end-stage renal failure and systemic oxalosis. To provide a non-invasive means of accessing kidney cells from individuals with primary hyperoxaluria, we have derived primary cultures of renal proximal tubule cells from the urine of these patients. The cells stain positively for the epithelial markers pan-cytokeratin and zonula occludens 1 and the proximal tubule marker gamma-glutamyl transpeptidase. Mutation analysis confirmed that the cultured cells had the same genotype as the leucocytes of the patients and also expressed glyoxylate reductase at the mRNA level, illustrating their potential value as a source of renal material from these individuals.

Angiopoietin-1 therapy enhances fibrosis and inflammation following folic acid-induced acute renal injury

The loss of interstitial capillaries is a feature of several experimental models of renal disease and this contributes to secondary kidney injury. Angiopoietin-1 is a secreted growth factor which binds to Tie-2 present on endothelia to enhance cell survival thereby stabilizing capillary architecture in-vitro. Previous studies showed that angiopoietin-1 prevented renal capillary and interstitial lesions following experimental ureteric obstruction. We tested here the effect of angiopoietin-1 treatment on capillary loss and associated tubulointerstitial damage known to follow recovery from folic acid-induced tubular necrosis and acute renal injury. We found that delivery of angiopoietin-1 by adenoviral vectors stabilized peritubular capillaries in folic acid nephropathy but this was accompanied by profibrotic and inflammatory effects. These results suggest that the use of endothelial growth factor therapy for kidney disease may have varying outcomes that depend on the disease model tested.

Factors that impact symptomatic diabetic peripheral neuropathy in placebo-administered patients from two 1-year clinical trials

OBJECTIVE

The purpose of this study was to evaluate the change in neuropathy symptoms and disease progression in placebo-administered patients from two 1-year studies in which the impact of ruboxistaurin (RBX) in mild diabetic peripheral neuropathy (DPN) was tested.

RESEARCH DESIGN AND METHODS

Data from 262 placebo-administered patients from two identical phase 3, randomized, double-blind trials were combined and analyzed.

RESULTS

After 1 year, change in the neuropathy impairment score of lower limbs [NIS(LL)] (-0.63 points; P = 0.005), vibration detection threshold (VDT) (-0.42 just noticeable difference units; P = 0.003), and Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire (-3.73 points; P < 0.001) improved, whereas some electrophysiology measures and heart rate deep breathing (HRDB) (-0.78 beats; P = 0.003) worsened compared with baseline values. There was a small but significant worsening of A1C (0.28%; P < 0.001), and a greater percentage of patients were using analgesics at the end of the trials (33.6%; P = 0.003). At 1 year, the change in NTSS-6 directly correlated with changes in NIS(LL) and VDT and inversely correlated with the peroneal nerve conduction velocity. On logistic regression analyses, a > or = 50% reduction in NTSS-6 score was less likely in patients who used antihypertensive or chronic symptom medication at baseline.

CONCLUSIONS

In placebo-administered patients with mild symptomatic DPN, there was a progressive improvement in symptoms over 12 months, whereas nerve conduction studies and HRDB declined, and clinically significant worsening of DPN would require > 1 year of observation.

Correlation of vibratory quantitative sensory testing and nerve conduction studies in patients with diabetes

Monitoring the course of diabetic peripheral neuropathy (DPN) remains a challenge. Besides clinical examination, nerve conduction studies (NCS) and quantitative sensory testing (QST) are the most commonly used methods for evaluating peripheral nerve function in clinical trials and population studies. In this study the correlation between vibratory QST and NCS was determined. Patients (N = 227) with diabetes mellitus participated in this multicenter, single-visit, cross-sectional study. QST of vibration measured with the CASE IV system was compared with a composite score of peroneal motor and tibial motor NCS and with individual attributes of peroneal, tibial, and sural nerves. The correlation between QST and composite score of NCS was 0.234 (Pearson correlation coefficient, P = 0.001). The correlations between QST and individual attributes of NCS ranged from 0.189 to 0.480 (Pearson correlation coefficients, P < 0.001). The low to moderate correlation between QST and NCS suggests that these tests cannot replace each other but are complementary.

Vascular endothelial growth factor administration does not improve microvascular disease in the salt-dependent phase of post-angiotensin II hypertension

Renal microvascular injury and tubulointerstitial inflammation may provide a potential mechanism for the development of salt-sensitive hypertension. Therefore, we hypothesized that vascular endothelial growth factor (VEGF) administration would prevent the development of salt-sensitive hypertension induced by ANG II. Infusion of ANG II in rats for 2 wk led to an elevation in blood pressure and an increase in blood urea nitrogen. Prominent tubular injury, focal areas of peritubular capillary loss accompanied by a decrease in urinary nitrites, thickening of the afferent arteriole, and an elevation in systemic and renal VEGF protein levels also occurred. In separate studies, animals were infused with ANG II and then placed on a low-salt diet for 1 wk. At this point, the animals were paired on the basis of weight and blood pressure and treated with either VEGF121or vehicle subcutaneously for 8 wk while being fed a high-salt diet. During the treatment period, a spontaneous improvement in many parameters, including both renal function and healing of the peritubular capillaries, occurred to the same degree in both vehicle- and VEGF121-treated rats. VEGF121significantly reduced blood pressure and accelerated the recovery of tubular injury. In contrast, vehicle-treated rats demonstrated a persistent increase in afferent arteriolar media-to-lumen ratio, which was further enhanced in rats treated with VEGF121. Therefore, VEGF therapy has only limited benefits on the healing of renal lesions in the salt-dependent phase of post-ANG II-mediated hypertension.

Clinical safety of the selective PKC-β inhibitor, ruboxistaurin

The aim of this manuscript is to report the safety profile of patients treated with ruboxistaurin mesylate (RBX; LY333531), a selective protein kinase C-beta (PKC-beta) inhibitor, for up to 4 years. Data from patients with diabetes (1396 RBX 32 mg/day; 1408 placebo) were combined from 11 placebo-controlled, double-masked studies. The proportion of patients who reported one or more serious adverse events was greater in the placebo group than in the RBX-treated group (23.2 versus 20.8%, respectively). There were 51 deaths (21 RBX; 30 placebo) reported in this patient cohort; none of the deaths was attributed to study drug by the investigators. Common adverse drug reactions (> or = 1/100 - < 1/10 patients) that were reported in the RBX-treated patients were dyspepsia and increased blood creatine phosphokinase. In controlled, randomised clinical trials, RBX had an adverse event profile comparable to placebo, and was well tolerated.

Microarray interrogation of human metanephric mesenchymal cells highlights potentially important molecules in vivo

Many molecules have been implicated in kidney development, often based on experimental animal studies with organ cultures and cell lines. There are very few studies, however, that have directly addressed equivalent living human embryonic tissues. We generated renal mesenchymal cell lines from normal human metanephroi and used a microarray strategy to define changes in gene expression after stimulation with growth factors which enhance nephrogenesis in rodents. Changes were observed in 1) genes modulating diverse general cellular processes, such as matrix metalloproteinase 1 and stanniocalcin 1; 2) genes previously implicated in organogenesis e.g., sprouty 4 and midline 1; and 3) genes involved in blood vessel growth, including angiopoietin 1 and 4. Expression of these same genes was subsequently confirmed in vivo. Our novel data have identified several previously unhighlighted genes that may be implicated in differentiation programs within early human nephrogenesis.

Treatment of symptomatic diabetic peripheral neuropathy with the protein kinase C beta-inhibitor ruboxistaurin mesylate during a 1-year, randomized, placebo-controlled, double-blind clinical trial

OBJECTIVE

The aim of this study was to assess the effects of ruboxistaurin (RBX) mesylate on nerve function and sensory symptoms in patients with diabetes mellitus (DM) and diabetic peripheral neuropathy (DPN).

METHODS

Patients were enrolled in a multinational, randomized, Phase II, double-blind, placebo-controlled parallel-group trial comparing 32 mg/d or 64 mg/d RBX with placebo for 1 year. DPN was identified by abnormal measurable vibration detection threshold (VDT) and verified by abnormal neurologic examination and nerve electrophysiology measures. Baseline patient characteristics (eg, sex, type of DM, age, body mass index, glycosylated hemoglobin, and duration of DM and DPN) were measured. The primary end point was the change in VDT. Secondary end point measures included effects of RBX versus placebo on Neuropathy Total Symptom Score-6 (NTSS-6), neurologic examination, electrophysiologic nerve conduction studies, Neuropathy Impairment Score, Clinical Global Impressions, and safety. A post-hoc analysis was performed on patients with less severe DPN (sural sensory nerve action potential > or =0.5 microV and NTSS-6 total score >6).

RESULTS

Two hundred five patients were assessed: 66 were assigned to the RBX 32 mg/d group, 71 to the RBX 64 mg/d group, and 68 to the placebo group. The demographic and baseline characteristics of the treatment groups were well matched between the RBX 32 mg/d, RBX 64 mg/d, and placebo groups: mean (SD) age, 45.6 (8.41) years; 122 (60%) men, 83 (40%) women; 110 (54%) with type 1 DM, 95 (46%) with type 2 DM; mean (SD) duration of DPN, 3.4 (4.21) years. The RBX 32 mg/d group had slightly more patients with type 1 DM (P = 0.05). Eighty-three patients had clinically significant symptoms at baseline (defined as NTSS-6 total score >6: RBX 32 mg/d, n = 22; RBX 64 mg/d, n = 26; placebo, n = 35); 122 patients had NTSS-6 total scores < or =6. No treatment differences were observed for change in VDT. Among the 83 patients with significant symptoms at baseline, there was a reduction from baseline at 12 months in the NTSS-6 total score in the RBX 32 mg/d (P = NS) and RBX 64 mg/d (P = 0.015) groups compared with placebo. In a subgroup of patients with clinically significant symptoms and less severe DPN (n = 50), there was a significantly greater reduction in the NTSS-6 total score with RBX 64 mg/d (P = 0.006 vs placebo). Furthermore, in these patients, there was a statistically significant improvement in VDT for both RBX 32 mg/d (P = 0.012) and RBX 64 mg/d (P = 0.026) compared with placebo.

CONCLUSIONS

RBX appeared to be well tolerated in the patients with DPN who participated in this study. Overall, changes in VDT and NTSS-6 total scores did not differ among treatment groups at end point. However, RBX treatment appeared to be of benefit for the subgroup of patients with less severe symptomatic DPN by relieving sensory symptoms and improving nerve fiber function, as indicated by reductions in VDT and NTSS-6 total score.

Development and validity testing of the neuropathy total symptom score-6: questionnaire for the study of sensory symptoms of diabetic peripheral neuropathy

OBJECTIVE

The aim of this study was to develop and validate a neuropathy sensory symptom scale, the Neuropathy Total Symptom Score-6 (NTSS-6), which evaluates individual neuropathy sensory symptoms in patients with diabetes mellitus (DM) and diabetic peripheral neuropathy (DPN) in clinical trials, with the intent of distinguishing a response to therapy.

METHODS

The NTSS-6 questionnaire was developed to evaluate the frequency and intensity of individual neuropathy sensory symptoms identified frequently by patients with DPN (ie, numbness and/or insensitivity; prickling and/or tingling sensation; burning sensation; aching pain and/or tightness; sharp, shooting, lancinating pain; and allodynia and/or hyperalgesia). The NTSS-6 was administered 8 times over a 1-year period to DPN patients. The NTSS-6's reliability (determined by internal consistency and test-retest reproducibility), construct validity, convergent validity, and minimally clinically important differences (MCIDs) were determined.

RESULTS

The NTSS-6 was administered to a total of 205 patients at 10 centers in the United States, Canada, Belgium, Germany, Hungary, Croatia, Slovenia, and the United Kingdom. Internal consistency was demonstrated at all 8 visits (Cronbach's alpha > 0.7). Test-retest reproducibility (intraclass correlation coefficient >0.9) was observed during the baseline period and at end point. Construct validity was demonstrated by statistically significant correlations between the NTSS-6 total score and the Neuropathy Symptoms and Change (NSC) score (r = 0.773-0.885, P < 0.001). Convergent validity was demonstrated by statistically significant correlations between the change in NTSS-6 total scores and the following: change in NSC scores (r = 0.519-0.708, P < 0.001); change in Neuropathy Impairment Score of the Lower Limbs and composite nerve function scores (r = 0.188-0.202, P < 0.007), and categories of the Clinical Global Impressions (r = 0.402, P < 0.001). The within- and between-groups MCIDs for the total NTSS-6 total scores were -1.26 and 0.97 points, respectively. The mean (SD) within-group MCID for all patients who improved on the Clinical Global Impression was -2.29 (3.4) points.

CONCLUSIONS

The NTSS-6 provided a valid assessment of neuropathy sensory symptoms in this sample of patients with DM and DPN, which suggests that it may be useful for symptom evaluation in clinical trials and practice. The NTSS-6 showed internal consistency, test-retest reliability, and construct validity. There was also convergent validity of the scores, indicating that the NTSS-6 may be a suitable questionnaire for clinical trials that evaluate symptoms of DPN in this well-defined patient population.

Human vascular smooth muscle cells express a urate transporter

An elevated serum uric acid is associated with the development of hypertension and renal disease. Renal regulation of urate excretion is largely controlled by URAT1 (SLC22A12), a member of the organic anion transporter superfamily. This study reports the specific expression of URAT1 on human aortic vascular smooth muscle cells, as assessed by reverse transcription-PCR and Western blot analysis. Expression of URAT1 was localized to the cell membrane. Evidence that the URAT1 transporter was functional was provided by the finding that uptake of 14C-urate was significantly inhibited in the presence of probenecid, an organic anion transporter inhibitor. It is proposed that URAT1 may provide a mechanism by which uric acid enters the human vascular smooth muscle cell, a finding that may be relevant to the role of uric acid in cardiovascular disease.

Sural sensory action potential identifies diabetic peripheral neuropathy responders to therapy

Identifying patients with diabetic peripheral neuropathy (DPN) amenable to therapy is a challenge. To determine whether the amplitude of the sural sensory nerve action potential (sural SNAP) reflects the severity of DPN, an analysis was performed on 205 patients with DPN, identified by an abnormal vibration detection threshold (VDT), who were enrolled in a multinational clinical trial investigating ruboxistaurin (RBX) mesylate. Nerve conduction velocity and response amplitude and latency were measured and compared. VDT was significantly lower in those with preserved sural SNAPs (n = 128) than in those in whom they were absent (n = 77; 21.5 vs. 22.7 JND units, P = 0.002). Thus, preserved sural SNAP denoted less severe DPN. Logistic regression analyses evaluating baseline characteristics, HbA(1c), and baseline symptom scores identified only DPN duration as a factor that might contribute to the presence of sural SNAP (P = 0.004; OR = 0.896). For patients with abnormal VDT, preserved sural SNAP identifies a patient population with less severe DPN who may respond to therapeutic intervention in clinical trials.

Loss of nitric oxide and endothelial-derived hyperpolarizing factor-mediated responses in aging

BACKGROUND

Aging has considerable structural and functional effects on the vascular system of the kidney. One such effect is an alteration in vascular tone which potentially will initiate renal damage. Vascular tone is determined by the balance between vasoconstrictors and vasodilators. Therefore, we hypothesized that aging attenuates vasodilatory responses in the kidney. These changes may be mediated by a loss of nitric oxide and endothelial-derived hyperpolarizing factor (EDHF).

METHODS

The systemic and renal responses of nitric oxide and EDHF were investigated in aging (18 months old) and young (3 months old) Sprague-Dawley rats.

RESULTS

We demonstrated a general loss of vasodilatory responses in the aging kidney. In addition, nitric oxide levels were reduced in the serum and kidney cortex of aging versus young animals, although this was not accompanied with a loss of endothelial nitric oxide synthase (eNOS) protein in the kidney cortex. Aging animals also exhibited a loss in EDHF-mediated vasodilation following stimulation with either acetylcholine or bradykinin in the isolated perfused kidney.

CONCLUSION

These findings indicate that not only a defect in the nitric oxide pathway, but also a loss of EDHF-mediated responses may be responsible for impaired vasodilation in the aging kidney. This may result in enhanced vasoconstrictive responses in aging which potentially will cause renal damage and ultimately a loss in glomerular filtration rate (GFR).

Blood vessels and the aging kidney

Aging is associated with a degenerative effect on many organs including the kidney. Blood vessels play a key role in the progression of renal damage in aging, with reductions in glomerular filtration rate and renal blood flow. Therefore, there is considerable interest in the haemodynamic and molecular mechanisms that may be responsible for alterations in the vascular system in aging. In this review, we will describe the evidence that aging is accompanied by alterations in vascular tone and angiogenesis alongside renal damage. The contributions of mediators such as nitric oxide, angiotensin II and vascular endothelial growth factor will also be discussed.

The prevalence of interferon-alpha transcription defects in malignant melanoma

The type I interferons, interferon-alpha (IFN-alpha) and interferon-beta (IFN-beta), are situated on the short arm of chromosome 9, specifically 9p21-22. This locus lies very close to an area that is deleted or rearranged in nearly half of all melanomas tested. The identification of 9p rearrangements in both melanoma precursor lesions (dysplastic naevi) and primary lesions has implicated the 9p locus in the early stages of melanoma development. Recent evidence has demonstrated that metastatic melanoma cell lines have a specific loss of IFN-alpha gene expression, a defect that appears to occur at the level of transcription. In this study, we examined the expression of IFN-alpha in cell lines isolated from the various stages of melanoma progression, with a view to determine the prevalence of the IFN-alpha transcription defects exhibited by malignant melanoma, and to assess whether the loss of IFN-alpha expression was particular to a certain stage of melanoma progression. We showed that all the melanoma cell lines tested (n=20) demonstrated an inability to express IFN-alpha, a defect that was reflected in the apparent inactivity of the IFN-alpha promoter. These defects were found to occur in cells isolated from early melanomas, lending support to the hypothesis that IFN-alpha has a role in the aetiology of malignant melanoma.

Evolving concepts in human renal dysplasia

Human renal dysplasia is a collection of disorders in which kidneys begin to form but then fail to differentiate into normal nephrons and collecting ducts. Dysplasia is the principal cause of childhood end-stage renal failure. Two main theories have been considered in its pathogenesis: A primary failure of ureteric bud activity and a disruption produced by fetal urinary flow impairment. Recent studies have documented deregulation of gene expression in human dysplasia, correlating with perturbed cell turnover and maturation. Mutations of nephrogenesis genes have been defined in multiorgan dysmorphic disorders in which renal dysplasia can feature, including Fraser, renal cysts and diabetes, and Kallmann syndromes. Here, it is possible to begin to understand the normal nephrogenic function of the wild-type proteins and understand how mutations might cause aberrant organogenesis.

Evaluation of the total peroxyl radical-scavenging capacity of flavonoids: structure-activity relationships

The antioxidant activity of a series of flavonoids against peroxyl radicals generated from thermal homolysis of 2, 2'-azobis-amidinopropane was determined by the Total Oxyradical Scavenging Capacity (TOSC) assay. Seven flavonoids with hydroxy and/or methoxy substitution were analyzed and compared to the water-soluble vitamin E analogue Trolox. The most active compound was the flavonol quercetin, followed by its 3-glycoside derivative rutin; these were 7 and 5 times, respectively, better scavengers of peroxyl radical than Trolox. Among the flavones with both hydroxy and methoxy substitution, the most active against peroxyl radicals was the 5,6,4'-trihydroxy-7,8,3'-trimethoxyflavone (thymonin), with a TOSC value 1.5 times greater than that of Trolox. The activity of the remaining flavones was in the following relative order: 5, 4'-dihydroxy-6,7,8,3'-tetramethoxyflavone > 5-hydroxy-3,6,7,3', 4'-pentamethoxyflavone (artemetin) > 5,4'-dihydroxy-3,6, 7-trimethoxyflavone > 5,6,7,8,2',3',4',5'-octamethoxyflavone (agehoustin A). The data suggest a potential role for dietary intake of flavonoid-containing foods in lowering the risk of certain pathophysiologies that have been associated with free-radical-mediated events.

A multinational investigation of the impact of subcutaneous sumatriptan. I: Design, methods and clinical findings

This report describes the design, methods and clinical results of a prospective sequential multinational (5 countries) study conducted to evaluate the effects of subcutaneous sumatriptan on health-related quality of life, workplace productivity, clinical parameters and patient satisfaction. Adult patients with moderate to severe migraine initially received customary therapy for migraine episodes for 12 weeks, followed by 24 weeks' treatment with self-administered subcutaneous sumatriptan 6 mg. Demographic, baseline, health-related quality of life and patient satisfaction rating data were collected during visits to the clinic. Data relating to migraine symptoms, migraine therapy, work productivity and non-work activity time were collected on diary cards filled out by the patients. 749 patients were recruited to the study and 637 received at least 1 dose of sumatriptan. Overall, 75.5% of migraines were successfully treated within 2 hours with sumatriptan compared with 31.9% with customary therapy; 36% of patients reported complete relief at 2 hours with sumatriptan treatment compared with 1% of patients receiving customary therapy. 69% of patients successfully treated 70% of their migraines with sumatriptan within 2 hours, compared with 12% of patients with customary therapy. No serious adverse events were reported; 50% of patients reported an adverse event during the 12-week customary therapy phase and 89% of patients during the 24-week sumatriptan phase. These clinical results, which are consistent with those reported in randomised blinded studies of subcutaneous sumatriptan, suggest that relief of migraine symptoms occurs more often, and in less time, in patients receiving subcutaneous sumatriptan rather than customary therapy as their primary medication.

A multinational investigation of the impact of subcutaneous sumatriptan. IV: Patient satisfaction

This report describes the patient satisfaction results from a prospective, sequential, multinational study. The study was conducted to concurrently evaluate the effects of sumatriptan, compared with customary therapy, on clinical parameters, health-related quality of life, productivity and patient satisfaction in adult patients with moderate to severe migraine. Patients treated migraine attacks for 12 weeks with their customary therapy, followed by 24 weeks' treatment with subcutaneous sumatriptan 6 mg. A questionnaire was conducted at the end of each study phase, or retrospectively at the end of the study, to assess patient satisfaction with customary therapy and sumatriptan. Sumatriptan was considered by most patients (67 to 85%) to be dependable and fast-acting, and to have a long duration of effect, allowing a quick return to normal activities. By comparison, 15 to 32% of patients considered that their customary therapy possessed the same attributes. However, customary therapy was considered to be easy/very easy to use by 82% of patients compared with 62% for subcutaneous sumatriptan. 89% of patients indicated that they would use sumatriptan again in the future. This study demonstrates that treatment of migraine attacks with subcutaneous sumatriptan for 24 weeks is associated with greater patient satisfaction as regards specific drug attributes than customary therapy.

Burden of migraine. A review of its socioeconomic impact

According to population-based epidemiological studies using International Headache Society diagnostic criteria, the prevalence of migraine in developed countries ranges from 8 to 14%. These prevalence figures confirm the widespread nature of the disorder. Moreover, as migraine is a chronic episodic disorder that predominantly affects people during their working lives (between the ages of 25 and 55 years), indirect costs associated with reduced productivity represent a substantial proportion of the total cost of migraine. The results of health-related quality-of-life studies demonstrate that migraine has a considerable impact on functional capacity, resulting in disrupted work and social activities. Many migraineurs, however, do not seek medical attention, have not been accurately diagnosed by a physician or do not use prescription medication. Therefore, the direct costs of treatment for migraine are relatively small compared with the indirect costs. Migraine is an important chronic illness that has a major impact on the working sector of a population. The overall cost attributable to migraine is unknown, but it is now established that the indirect costs of migraine outweigh the direct costs and therefore represent an obvious target for healthcare intervention aimed at reducing the impact of this chronic condition.

Association of prokaryotes with symptomatic appearance of withering syndrome in black abalone Haliotis cracherodii

Withering syndrome (WS) is an epizootic fatal wasting disease that is devastating California Channel Island populations of black abalone Haliotis cracherodii. Our studies suggest a strong pathogen-disease association. The pathogen is an intracellular prokaryote that infects epithelial cells lining the gut and enzyme secreting cells of the digestive diverticula. It multiplies by binary fission in round to oval, basophilic, membrane-bound colonies teeming in the cytoplasm. Infection of the digestive diverticula is accompanied by a complete loss of digestive enzyme granules and metaplasia of enzyme secretory cells to a morphology similar to epithelium lining the gut. Extensive infection of digestive diverticular cells and the resultant deficiency in digestive enzymes correlates to the degree of pedal muscle atrophy and the severity of signs associated with WS. Electron microscopically the intracellular pathogen is a rod-shaped, ribosome-rich, gram-negative, prokaryote with a trilaminar cell wall consistent with the order Rickettsiales. Microbiological and protozoological methods produced no patterns that implicated other types of microbes. Chemical analysis of tissue from animals from a population with WS did not support an association between WS and environmental pollutant exposure to polycyclic aromatic hydrocarbons, polychlorinated biphenyls, or chlorinated pesticides.