Renal arteriolar hyalinosis, not intimal thickening in large arteries, is associated with cardiovascular events in people with biopsy-proven diabetic nephropathy.

AIMS: Diabetic nephropathy, a pathologically diagnosed microvascular complication of diabetes, is a strong risk factor for cardiovascular events, which mainly involve arteries larger than those affected in diabetic nephropathy. However, the association between diabetic nephropathy pathological findings and cardiovascular events has not been well studied. We aimed to investigate whether the pathological findings in diabetic nephropathy are closely associated with cardiovascular event development. METHODS: This retrospective cohort study analysed 377 people with type 2 diabetes and biopsy-proven diabetic nephropathy, with a median follow-up of 5.9 years (interquartile range 2.0 to 13.5). We investigated how cardiovascular events were impacted by two vascular diabetic nephropathy lesions, namely arteriolar hyalinosis and arterial intimal thickening, and by glomerular and interstitial lesions. RESULTS: Of the 377 people with diabetic nephropathy, 331 (88%) and 295 (78%) had arteriolar hyalinosis and arterial intimal thickening, respectively. During the entire follow-up period, those with arteriolar hyalinosis had higher cardiovascular event rates in the crude Kaplan-Meier analysis than those without these lesions (P = 0.005, log-rank test). When fully adjusted for clinically relevant confounders, arteriolar hyalinosis independently predicted cardiovascular events [hazard ratio (HR) 1.99; 95% confidence interval (CI) 1.12, 3.86], but we did not find any relationship between arterial intimal thickening and cardiovascular events (HR 0.89; 95% CI 0.60, 1.37). Additionally, neither glomerular nor interstitial lesions were independently associated with cardiovascular events in the fully adjusted model. CONCLUSIONS: Arteriolar hyalinosis, but not intimal thickening of large arteries, was strongly associated with cardiovascular events in people with diabetic nephropathy.

Resolution of mesangial light chain deposits 3 years after high-dose melphalan with autologous peripheral blood stem cell transplantation.

A 52-year-old woman was admitted to our hospital for treatment of nephrotic syndrome. Funduscopic findings showed fundal hemorrhage and soft exudates, and serologic analysis showed a monoclonal serum component that was identified as Bence Jones protein-k type. A bone marrow biopsy showed diffuse proliferation of atypical plasma cells, while a renal biopsy showed diffuse and nodular mesangial proliferation. Immunohistochemical staining confirmed the presence of k chains along the glomerular basement membrane and in mesangial areas. The patient was diagnosed as multiple myeloma (Bence Jones k type) with light chain deposition disease (LCDD). After high-dose melphalan and autologous peripheral blood stem cell transplantation (PBSCT), the multiple myeloma and nephrotic syndrome were in complete remission; her renal function was improved, but a renal biopsy performed 6 months after PBSCT showed the persistence of diffuse and nodular lesions. By contrast, a renal biopsy performed 3 years later showed complete resolution of the diffuse and nodular mesangial proliferation.

Regulation of abdominal adiposity by probiotics (Lactobacillus gasseri SBT2055) in adults with obese tendencies in a randomized controlled trial.

BACKGROUND/OBJECTIVES: In spite of the much evidence for the beneficial effects of probiotics, their anti-obesity effects have not been well examined. We evaluated the effects of the probiotic Lactobacillus gasseri SBT2055 (LG2055) on abdominal adiposity, body weight and other body measures in adults with obese tendencies. SUBJECTS/METHODS: We conducted a multicenter, double-blind, randomized, placebo-controlled intervention trial. Subjects (n=87) with higher body mass index (BMI) (24.2-30.7 kg/m(2)) and abdominal visceral fat area (81.2-178.5 cm(2)) were randomly assigned to receive either fermented milk (FM) containing LG2055 (active FM; n=43) or FM without LG2055 (control FM; n=44), and were asked to consume 200 g/day of FM for 12 weeks. Abdominal fat area was determined by computed tomography. RESULTS: In the active FM group, abdominal visceral and subcutaneous fat areas significantly (P<0.01) decreased from baseline by an average of 4.6% (mean (confidence interval): -5.8 (-10.0, -1.7) cm(2)) and 3.3% (-7.4 (-11.6, -3.1) cm(2)), respectively. Body weight and other measures also decreased significantly (P<0.001) as follows: body weight, 1.4% (-1.1 (-1.5, -0.7) kg); BMI, 1.5% (-0.4 (-0.5, -0.2) kg/m(2)); waist, 1.8% (-1.7 (-2.1, -1.4) cm); hip, 1.5% (-1.5 (-1.8, -1.1) cm). In the control group, by contrast, none of these parameters decreased significantly. High-molecular weight adiponectin in serum increased significantly (P<0.01) in the active and control groups by 12.7% (0.17 (0.07, 0.26) microg/ml) and 13.6% (0.23 (0.07, 0.38) microg/ml), respectively. CONCLUSION: The probiotic LG2055 showed lowering effects on abdominal adiposity, body weight and other measures, suggesting its beneficial influence on metabolic disorders.

Nutritional status of people living in Dzong village, in the northern mountainous area of Nepal.

A nutritional survey was carried out among residents (39 males and 46 females) of Dzong village in the northern area of the Gandaki region of Nepal. The results were compared with our previous findings. The mean body mass index value was under 21 for both sexes, but the mean percentage of body fat of females (17-19 years old, 25.8 +/- 9.4%; 20-29 years old, 31.0 +/- 8.4%) was higher than that of males (17-19 years old, 12.0 +/- 1.0%; 50-59 years old, 24.4 +/- 7.6%). Most serum nutritional markers for both sexes were generally at normal levels although the iron levels were lower and packed red cell volume levels were higher than normal. As determined by results of the 24-hr dietary recall survey, the main food groups consumed by both sexes were cereals, potatoes, pulses, meats and vegetables. The mean daily intake of nutrients was similar for both sexes, with a few exceptions. The relatively high serum TG levels of the subjects may have been due to the high consumption of carbohydrate-laden cereals. The amounts of food consumed were not adequate, resulting in a latent and chronic deficiency of nutrients, especially calcium and iron. These results suggest that improvements in the nutritional status of this group of people are necessary.

Tubulointerstitial macrophage infiltration in a patient with hypokalemic nephropathy and primary Sjögren's syndrome.

We report a case of hypokalemic nephropathy associated with primary Sjögren's syndrome (SS). The patient presented with profound and persistent hypokalemia secondary to distal renal tubular acidosis (RTA). A renal biopsy exhibited tubular degeneration, marked interstitial fibrosis and intense macrophage infiltration. Hypokalemia has been reported to induce macrophage infiltration in experimental animal models but not in humans. This is the first report of intense tubulointerstitial macrophage infiltration in a patient with hypokalemic nephropathy associated with SS.

Effect of ticlopidine hydrochloride on erythropoietin-induced rise in blood pressure in patients on maintenance hemodialysis.

BACKGROUND/AIMS: A recent observation that antiplatelet-aggregation drugs, including ticlopidine hydrochloride, may prevent erythropoietin (EPO)-induced rise in blood pressure in hemodialysis (HD) patients remains a subject of particular interest. The aim of the present study was to determine the effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure of HD patients with special reference to blood levels of vasoactive substances. METHODS: HD patients who showed hypertension or aggravation of preceding hypertension with EPO treatment were selected for this study. Ticlopidine hydrochloride was administered at a dose of 200 mg daily for 4 weeks. Blood pressure and serum levels of nitric oxide (NO), atrial natriuretic peptide (ANP) and endothelin (ET) were determined before and after drug administration. Patients were divided into two groups, one of which showed a drop in mean blood pressure (MBP) of >10 mm Hg (group I) and one which did not (group II), and a comparison was made between them with respect to the blood parameters. RESULTS: Five of 15 patients showed a drop of MBP of >10 mm Hg (group I), and 10 patients did not show any change in MBP (group II). In group I, there was a significant increase in blood NO levels compared to the concentrations before ticlopidine administration, while there was no change in group II. With respect to ANP and ET, there was no significant change in either of the groups. CONCLUSION: The findings suggest that the preventive effect of ticlopidine hydrochloride on EPO-induced rise in blood pressure may partly be related to the enhancement of NO production in patients on maintenance HD.

Vascular endothelial growth factor mRNA synthesis by peripheral blood mononuclear cells in patients with acute myocardial infarction.

We studied vascular endothelial growth factor (VEGF) mRNA synthesis by peripheral blood mononuclear cells (PBMCs) in 30 patients with acute myocardial infarction (AMI) and 20 healthy individuals. PBMCs were isolated from all patients on days 3 and 14 after the onset of aMI, and from all of control individuals. To prepare samples containing identical amounts of GAPDH cDNA, competitive PCR was performed by co-amplifying serial dilutions of GAPDH mutant templates. Next, to measure VEGF cDNA quantitatively in the samples containing identical amounts of GAPDH, we also used competitive PCR by co-amplifying mutant templates of VEGF. The serum VEGF concentrations on day 14 in patients with aMI were measured by an ELISA method. Higher levels of VEGF mRNA in PBMCs were present on day 14 than either on day 3 or in the control group. Serum VEGF concentrations correlated with the VEGF mRNA levels of PBMCs on day 14. Peak serum CK levels correlated well with VEGF mRNA levels of PBMCs on day 14. The present findings suggest that PBMCs may be one of the candidates responsible for elevated circulatory VEGF protein following aMI. In addition, VEGF mRNA may be overexpressed in PBMCs in response to cardiac muscle damage.

A rapid, simple and sensitive flow cytometric system for detection of Plasmodium falciparum.

We have established a rapid, simple and sensitive flow cytometric system for the detection of Plasmodium falciparum that involves lysing erythrocytes and staining parasites at the same time using a newly developed hemolysing and staining solution containing dodecyl methyl ammonium chloride and acridine orange. In this system, freed parasites of P. falciparum could be plotted separately from erythrocyte ghosts, white blood cells and platelets on the two-dimensional scattergram of forward-angle light scatter and green fluorescence by flow cytometry with an argon laser. It took only 2-3 min per sample to obtain the scattergram and analyze the data, including the time of sample preparation for flow cytometric analysis. Sample preparation with this method does not require any difficult handling procedures. The threshold of parasite detection was almost equal to that of microscopic examination for cultured P. falciparum. The results of drug-susceptibility assays using this system were also almost identical to those obtained using microscopic examination. In this system, parasites at different erythrocytic stages could be easily distinguished. This system must prove useful and practical for basic laboratory studies of P. falciparum including those requiring the differential measurement of parasites at specific erythrocytic stages.

Association of transforming growth factor-beta1 T29C polymorphism with the progression of diabetic nephropathy.

Diabetes mellitus is a leading cause of end-stage renal disease in the Western world. Histologically, mesangial expansion with increased extracellular matrix protein is observed in patients with diabetic nephropathy. Because transforming growth factor (TGF)-beta promotes extracellular matrix production in response to high glucose, TGF-beta is considered to play a central role in the pathogenesis of diabetic nephropathy. We investigated the association of TGF-beta1 T29C polymorphism and the progression of diabetic nephropathy. Forty patients with type 2 diabetes mellitus were enrolled. All patients had had diabetes for more than 10 years. DNA was extracted from peripheral blood cells, and genotype was determined using real-time polymerase chain reaction method. Patients were classified into three groups according to genotype: TT, TC, and CC. Grade of diabetic nephropathy was determined using the amount of urinary excretion of albumin. Demographic characteristics of the patients with each genotype were not statistically different. No differences in the glycemic control and the mode of therapy were observed. Among patients with three genotypes, the severity of diabetic nephropathy was not statistically different. The patients with TT genotype tended to have a higher rate of progression of nephropathy; however, no statistically significant difference was observed among the three groups. Our results suggest that TGF-beta1 T29C polymorphism is not associated with the progression of diabetic nephropathy. Further studies are required to determine the exact role of this polymorphism in the progression of diabetic nephropathy.

Selective hypoaldosteronism due to combined defects of the conversion from inactive renin to active renin and the aldosterone biosynthesis from corticosterone.

A 24-year-old Japanese woman with IgA nephropathy exhibited a decreased serum aldosterone level with normal plasma renin activity after toxemia of pregnancy. Our studies revealed selective hypoaldosteronism with normal adrenoglucocorticoid functions. Levels of serum corticosterone and deoxycorticosterone were normal. Resting plasma renin activity was normal, and plasma levels of total and inactive renin were increased. Rapid ACTH administration failed to stimulate any secretion of aldosterone, whereas it adequately increased serum cortisol, deoxycorticosterone, and corticosterone concentrations. Responses of both plasma renin activity and serum aldosterone level to the furosemide-posture challenge were blunted. Angiotensin II also failed to stimulate any secretion of aldosterone despite a progressive rise in blood pressure and an appropriate increase in serum corticosterone. These results suggest that combined defects of the conversion from inactive renin to active renin and aldosterone biosynthesis are the causes of selective hypoaldosteronism in our patient.

FcgammaRIIa polymorphism in Japanese patients with systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is an immune complex-mediated disease and organ damage is caused by the deposition of immune complex. Receptors which recognize the Fc portion of immunoglobulin G (FcgammaR) play a key role in the phagocytosis of immune complexes. As the gene encoding for FcgammaR of class IIa (FcgammaRIIa) has two allelic forms, H131 and R131, which differ in their affinity to IgG2, this polymorphism might have implications in handling immune complex. We studied the distribution of the FcgammaRIIa polymorphism in 90 Japanese patients with SLE. We also examined the association between FcgammaRIIa polymorphism and the disease activity of SLE and the histopathological findings of lupus nephritis. FcgammaRIIa polymorphism was determined by PCR and dot blot analysis. The allelic frequency of H131 in patients with SLE was significantly lower (H131/R131 = 0.44/0.56) than that of normal controls (H131/R131 = 0.62/0.38; P < 0.05). No significant association was observed between FcgammaRIIa polymorphism and the clinical parameters for the activity of SLE. There was no association between FcgammaRIIa polymorphism and the histological findings in lupus nephritis. The difference in the distribution of FcgammaRIIa alleles between patients with SLE and normal subjects indicates that this polymorphism is a candidate of susceptibility gene for SLE in Japanese.

[Effect of heparin cofactor II on the antithrombin III activities measured by thrombin methods or factor Xa methods--fundamental studies and clinical studies using the plasma of pregnant women].

We evaluated the effects of heparin cofactor II(HC II) on the antithrombin III(AT III) activities measured by the methods of thrombin or factor Xa. Reagents A and B were using the method of thrombin and reagent C was based on the method of Xa. Purified HC II was directly measured or indirectly measured after the dilution with control plasma. Cross reaction of HC II in AT III assay were negligible in reagent C, but substantial amount of AT III activities were measured in reagent A and B. Plasma AT III activities from full-term pregnant women were significantly higher than those from non pregnant control women in reagent A, but comparable in reagent B or C. These results indicate that AT III activities measured by thrombin methods by thrombin were overestimated in pregnant women due to the cross-reactivities of HC II. It is recommended that AT III activities would be measured by the methods of factor Xa.

Increased plasma levels of adrenomedullin in patients with systemic inflammatory response syndrome.

We measured the plasma levels of adrenomedullin (AM), a novel vasodilating peptide, in 89 patients with various forms of systemic inflammatory response syndrome (SIRS) and 13 healthy volunteers serving as controls. Plasma levels of AM in SIRS (burns: 20.5 +/- 3. 2 fmol/ml [mean +/- SEM]; pancreatitis: 13.8 +/- 3.8 fmol/ml; trauma: 14.9 +/- 2.5 fmol/ml; traumatic shock: 41.1 +/- 7.8 fmol/ml; severe sepsis: 59.9 +/- 11.2 fmol/ml; septic shock: 193.5 +/- 30.1 fmol/ml) were significantly increased over those of controls (5.1 +/- 0.2 fmol/ml). The patients with traumatic shock or septic shock especially had higher levels of plasma AM than those with trauma or severe sepsis, respectively. These data showed that in patients with SIRS, plasma AM levels increased in proportion to the severity of illness. Subsequently, we measured the plasma levels of mediators such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, IL-8, plasminogen activator inhibitor (PAI)-1, and thrombomodulin (TM) in patients with traumatic shock and septic shock. A significant correlation was observed between plasma AM and TNF-alpha levels in patients with septic shock, suggesting an important role for AM as well as of TNF-alpha in the pathophysiology of inflammation. Plasma AM and IL-8 levels correlated positively with Acute Physiology and Chronic Health Evaluation (APACHE) II score, peak multiple organ failure (MOF) score during the first month and prognosis in patients with septic shock, as did plasma IL-6 levels in patients with traumatic shock. The plasma AM level might serve as a useful marker for evaluating the severity of disease and as an early predictor of subsequent organ failure and outcome in septic shock.

Association of an insertion polymorphism of angiotensin-converting enzyme gene with the activity of lupus nephritis.

BACKGROUND: Lupus nephritis is a common manifestation of systemic lupus erythematosus (SLE). The pathogenesis of lupus nephritis has not been fully understood; however, immunological abnormalities have been considered in the development and activity of lupus nephritis. As angiotensin-converting enzyme (ACE) is implicated in various immunological phenomena, we investigated the correlation between insertion (I)/ deletion (D) polymorphism of the ACE gene and the activity of lupus nephritis. PATIENTS AND METHODS: Eighty-four patients with SLE and 100 healthy subjects were enrolled in this study. Following the extraction of genomic DNA from the peripheral blood, the ACE genotype was determined by the polymerase chain reaction. The patients were classified by the histological findings according to the WHO classification. In addition, the activity index and chronicity index were used to assess the severity of renal involvement. RESULTS: Individuals with II genotype showed a significantly increased activity of lupus nephritis. The allelic frequency was I/D = 0.84/0.16 in patients with WHO class IV renal lesions, and I/D = 0.36/0.64 in those with WHO class I lesions and 0.61/0.39 in patients with WHO class I or WHO class II. The difference in the allelic frequency between patients with WHO class IV and those with WHO class I or WHO class I + WHO class II was statistically significant (p = 0.00016 or p = 0.027, respectively). Moreover, lupus nephritis patients with II genotype showed significantly higher activity index than those with DD genotype (p = 0.0009). CONCLUSION: These results suggest that the insertion polymorphism of the ACE gene may correlate with the activity of lupus nephritis.

Association of an insertion polymorphism of angiotensin-converting enzyme gene with the activity of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) shows various clinical manifestations, which are characterized by inflammation in many different organ systems. The cause of SLE is still unclear; however, the immunological abnormalities are considered to be responsible for the pathogenesis of SLE. As angiotensin I-converting enzyme (ACE) has been reported to be associated with various immunological phenomena, we investigated the correlation between insertion (I)/deletion (D) polymorphism of the ACE gene and the disease activity of SLE. Ninety-three patients with newly diagnosed SLE were enrolled in this study. ACE genotype was determined by the polymerase chain reaction (PCR). We measured serum levels of anti-double-stranded (ds) DNA antibody (Ab) and serum levels of total complements (CH50) as the parameter for lupus activity. Moreover, we evaluated the clinical disease activity by calculating SLE disease activity index (SLEDAI). Individuals with II genotype showed a significant increase in SLE activity. Patients with the ACE II genotype showed a higher serum level of anti-dsDNA Ab (14.3 IU/ml (5.475, 74.6, median (25th centile, 75th centile)) than those with the DD genotype (4.65IU/ml (4.05, 6.8)) (P<0.01). Moreover, patients with the 11 genotype also showed lower levels of serum CH50 than those with the DD genotype (P < 0.01). Patients with the II1 or DI genotype had significantly higher SLEDAI score than those with the DD genotype (P < 0.01). These results suggest that the ACE genotype could be associated with the disease activity of SLE. ACE insertion polymorphism might be used as one of predictive factors for the activity of lupus.

Increased excretion of urinary transforming growth factor beta 1 in patients with diabetic nephropathy.

The accumulation of extracellular matrix in the glomeruli of human and experimental models of diabetic nephropathy is associated with disease progression. Transforming growth factor beta 1 (TGF-beta1), which is a multifunctional peptide growth factor, plays a key role in the synthesis of extracellular matrix protein in vitro, and the expression of TGF-beta1 is elevated in human and rat diabetic nephropathy. In this study, we measured the urinary TGF-beta1 excretion in 57 patients with non-insulin-dependent diabetes mellitus and in 20 healthy volunteers to examine whether the determination of urinary TGF-beta1 excretion would facilitate the evaluation of the degree of mesangial expansion in patients with diabetic nephropathy. Both active and total TGF-beta1 levels in 24-hour urine samples collected from patients with diabetes mellitus and normal controls were measured using an enzyme-linked immunosorbent assay. We observed a higher excretion of urinary TGF-beta1 in patients with diabetes mellitus than in normal controls. In addition, the urinary TGF-beta1 excretion was elevated in patients with severe mesangial expansion. These results suggest that urinary TGF-beta1 may represent one parameter that can be used to evaluate the progression of diabetic nephropathy.

Measurement of plasma and urinary adrenomedullin in patients with IgA nephropathy.

In this study, we measured plasma and urinary adrenomedullin (AM) concentrations in 47 patients with IgA nephropathy. Controls were 39 healthy volunteers. Plasma and urinary AM values were measured by specific radioimmunoassay. The plasma AM concentrations were higher, and the urinary AM levels were lower in patients with IgA nephropathy than in healthy volunteers. Plasma AM concentrations showed a positive correlation with serum creatinine and blood urea nitrogen, whereas urinary AM levels correlated negatively with serum creatinine and blood urea nitrogen. The plasma AM concentrations showed a positive correlation with fractional excretions of sodium and potassium. Renal biopsy specimens of patients without renal failure were scored for activity (percentage of glomeruli demonstrating cellular crescent formation, degree of mesangial proliferation and interstitial infiltration; total score = 9). Urinary AM levels were shown to be lower in the group with a high activity (score 3-9) as compared with the group with a low activity (score 0-2) based on renal biopsy. Thus, urinary levels of AM are affected by the degree of the activity in IgA nephropathy, and AM may participate in the pathophysiology of IgA nephropathy.

Serum levels of VEGF and basic FGF in the subacute phase of myocardial infarction.

We examined serial changes in serum levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) measured by ELISAs in 45 patients with acute myocardial infarction (AMI) who received heparin intravenously for 3 to 5 days after the onset and in 30 control subjects with an old myocardial infarction. To evaluate the effect of heparin on these serum levels, heparin was administered intravenously in 10 patients with AMI on day 21. Blood samples were obtained from all AMI patients on days 1, 2, 3, 7, 14, 21, and 28 and from 10 AMI patients before and 1 h after heparin administration. Serum VEGF level was significantly reduced after heparin administration (P<0.001). Serum samples from day 1 to 3 were therefore excluded from the subsequent analysis. Serum VEGF level in AMI patients was significantly higher on day 7 than in the control subjects (P<0.0001), and then decreased over time (P<0.0001). The serum VEGF level on day 7 was independently associated with the peak serum CK level (P<0.05). The serum bFGF level did not differ significantly between the AMI patients and the control subjects. In conclusion, the serum VEGF level may be selectively elevated during the healing process after AMI.

Increased plasma concentrations of adrenomedullin correlate with relaxation of vascular tone in patients with septic shock.

OBJECTIVE: To investigate plasma concentrations of adrenomedullin in patients with septic shock and the potential association of these concentrations with relaxation of vascular tone. DESIGN: Prospective, case series. SETTING: Department of Emergency and Critical Care Medicine, Nara Medical University. PATIENTS: Twelve patients who fulfilled the clinical criteria for severe sepsis or septic shock (as defined by the Members of the American College of Chest Physicians/Society of Critical Care Medicine Consensus Conference Committee) and 13 healthy volunteers. INTERVENTIONS: Arterial blood samples were obtained via a 20-gauge cannula inserted into each patient's radial artery. MEASUREMENTS AND MAIN RESULTS: After extraction and purification, plasma adrenomedullin was measured by radioimmunoassay. Systemic vascular resistance index, pulmonary vascular resistance, cardiac index, and stroke volume index were determined with a thermodilution catheter. The mean plasma concentration of adrenomedullin was markedly higher in patients than in controls (226.1 +/- 66.4 [SEM] vs. 5.05 +/- 0.21 fmol/mL, p < .01). Moreover, these concentrations correlated significantly with cardiac index, stroke volume index, and heart rate values, and correlated significantly with decreases in diastolic blood pressure, systemic vascular resistance index, and pulmonary vascular resistance index values. CONCLUSIONS: Enhanced production of adrenomedullin in patients with septic shock may contribute to reduced vascular tone, hypotension, or both. More data are needed to clarify the role of adrenomedullin in the regulation of vascular tone in this patient population.