Urine Albumin/Creatinine Ratio and Microvascular Disease in Elderly Hypertensive Patients without Comorbidities

OBJECTIVES

A high urine albumin/creatinine ratio (UACR) is associated with microvascular disease in hypertensive patients. However, hypertensive patients frequently have other comorbidities. Thus, it is difficult to distinguish the role of UACR from that of comorbidities in microvascular disease. The aim of this study was to evaluate the association between UACR and microvascular disease in elderly hypertension patients without comorbidities.

METHODS

A cross-sectional cohort study of 2252 essential hypertension patients aged 65-94 years without comorbidities between January 1, 2016, and December 31, 2017, was conducted. Microvascular disease was evaluated by hypertension retinopathy (HR). Multivariable adjusted odds of HR by UACR quartiles were determined using logistic regression.

RESULTS

The HR prevalence was 22.1% (n = 472) among the cohort study and was significantly different among UACR quartiles (19.7%, 20.3%, 22.0%, and 26.4% in quartiles 1, 2, 3, and 4, respectively, P = 0.036). After adjustment for covariates, higher UACR (odds ratio (OR) = 1.42, 95% confidence interval (CI) 1.05-1.92, quartile 4 versus 1) were significantly associated with HR. Among male patients, higher UACR (OR = 1.65, 95% CI 1.07-2.55, quartile 4 versus 1) were significantly associated with HR after adjustment for covariates. Among female patients, however, 64% and 40% increased odds of HR were noted in the highest and lowest UACR (quartiles 4 and 1, respectively) compared to UACR quartile 2.

CONCLUSIONS

Microvascular disease was associated with higher UACR in elderly male essential hypertension patients without comorbidities but was associated with lower and higher UACR in female patients without comorbidities.

Urine Arsenic and Arsenic Metabolites in U.S. Adults and Biomarkers of Inflammation, Oxidative Stress, and Endothelial Dysfunction: A Cross-Sectional Study

BACKGROUND

Arsenic (As) exposure has been associated with increased risk for cardiovascular disease (CVD) and with biomarkers of potential CVD risk and inflammatory processes. However, few studies have evaluated the effects of As on such biomarkers in U.S. populations, which are typically exposed to low to moderate As concentrations.

OBJECTIVES

We investigated associations between As exposures and biomarkers relevant to inflammation, oxidative stress, and CVD risk in a subset of participants from the New Hampshire Health Study, a population with low to moderate As exposure (n=418).

METHODS

Associations between toenail As, total urine As (uAs), and %uAs metabolites [monomethyl (%uMMA^V), dimethyl (%uDMA^V), and inorganic (%iAs) species] and plasma biomarkers, including soluble plasma vascular and cellular adhesion molecules (VCAM-1 and ICAM-1, respectively), matrix metalloproteinase-9 (MMP-9), tumor necrosis factor-α, plasminogen activator inhibitor-1 (PAI-1), and urinary oxidative stress marker 15-F_2t-isoprostane (15-F_2t-IsoP), were evaluated using linear regression models.

RESULTS

Covariate-adjusted estimates of associations with a doubling of urinary As suggested an 8.8% increase in 15-F_2t-IsoP (95% CI: 3.2, 14.7), and a doubling of toenail As was associated with a 1.7% increase in VCAM-1 (95% CI: 0.2, 3.2). Additionally, a 5% increase in %uMMA was associated with a 7.9% increase in 15-F_2t-IsoP (95% CI: 2.1, 14.1), and a 5% increase in %uDMA was associated with a 2.98% decrease in 15-F_2t-IsoP [(95% CI: -6.1, 0.21); p=0.07]. However, in contrast with expectations, a doubling of toenail As was associated with a 2.3% decrease (95% CI: -4.3, -0.3) in MMP-9, and a 5% increase in %uMMA was associated with a 7.7% decrease (95% CI: -12.6, -2.5) in PAI-1.

CONCLUSION

In a cross-sectional study of U.S. adults, we observed some positive associations of uAs and toenail As concentrations with biomarkers potentially relevant to CVD pathogenesis and inflammation, and evidence of a higher capacity to metabolize inorganic As was negatively associated with a marker of oxidative stress. https://doi.org/10.1289/EHP2062.

Effects of ambient coarse, fine, and ultrafine particles and their biological constituents on systemic biomarkers: a controlled human exposure study

BACKGROUND

Ambient coarse, fine, and ultrafine particles have been associated with mortality and morbidity. Few studies have compared how various particle size fractions affect systemic biomarkers.

OBJECTIVES

We examined changes of blood and urinary biomarkers following exposures to three particle sizes.

METHODS

Fifty healthy nonsmoking volunteers, mean age of 28 years, were exposed to coarse (2.5-10 μm; mean, 213 μg/m3) and fine (0.15-2.5 μm; mean, 238 μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (< 0.3 μm; mean, 136 μg/m3) and filtered medical air. Exposures lasted 130 min, separated by ≥ 2 weeks. Blood/urine samples were collected preexposure and 1 hr and 21 hr postexposure to determine blood interleukin-6 and C-reactive protein (inflammation), endothelin-1 and vascular endothelial growth factor (VEGF; vascular mediators), and malondialdehyde (lipid peroxidation); as well as urinary VEGF, 8-hydroxy-deoxy-guanosine (DNA oxidation), and malondialdehyde. Mixed-model regressions assessed pre- and postexposure differences.

RESULTS

One hour postexposure, for every 100-μg/m3 increase, coarse CAP was associated with increased blood VEGF (2.41 pg/mL; 95% CI: 0.41, 4.40) in models adjusted for O3, fine CAP with increased urinary malondialdehyde in single- (0.31 nmol/mg creatinine; 95% CI: 0.02, 0.60) and two-pollutant models, and ultrafine CAP with increased urinary 8-hydroxydeoxyguanosine in single- (0.69 ng/mg creatinine; 95% CI: 0.09, 1.29) and two-pollutant models, lasting < 21 hr. Endotoxin was significantly associated with biomarker changes similar to those found with CAPs.

CONCLUSIONS

Ambient particles with various sizes/constituents may influence systemic biomarkers differently. Endotoxin in ambient particles may contribute to vascular mediator changes and oxidative stress.

The contrasting relationships between betaine and homocysteine in two clinical cohorts are associated with plasma lipids and drug treatments

Background

Urinary betaine excretion positively correlated with plasma homocysteine in outpatients attending a lipid disorders clinic (lipid clinic study). We aimed to confirm this in subjects with established vascular disease.

Methods

The correlation between betaine excretion and homocysteine was compared in samples collected from subjects 4 months after hospitalization for an acute coronary episode (ACS study, 415 urine samples) and from 158 sequential patients visiting a lipid disorders clinic.

Principal findings

In contrast to the lipid clinic study, betaine excretion and plasma homocysteine did not correlate in the total ACS cohort. Differences between the patient groups included age, non-HDL cholesterol and medication. In ACS subjects with below median betaine excretion, excretion correlated (using log transformed data) negatively with plasma homocysteine (r = −0.17, p = 0.019, n = 199), with no correlation in the corresponding subset of the lipid clinic subjects. In ACS subjects with above median betaine excretion a positive trend (r = +0.10) between betaine excretion and homocysteine was not significant; the corresponding correlation in lipid clinic subjects was r = +0.42 (p = 0.0001). In ACS subjects, correlations were stronger when plasma non-HDL cholesterol and betaine excretion were above the median, r = +0.20 (p = 0.045); in subjects above median non-HDL cholesterol and below median betaine excretion, r = −0.26 (p = 0.012). ACS subjects taking diuretics or proton pump inhibitors had stronger correlations, negative with lower betaine excretion and positive with higher betaine excretion.

Conclusions

Betaine excretion correlates with homocysteine in subjects with elevated blood lipids.

Urinary cysteinyl leukotriene E(4) is associated with increased risk for pain and acute chest syndrome in adults with sickle cell disease

Leukotriene E(4) (LTE(4)) levels are associated with rate of pain episodes in children with sickle cell disease (SCD). Because complications of SCD manifest differently in adults than children, we examined a cohort of adults with SCD to determine the relationship between baseline LTE(4) and SCD-related morbidity. Baseline LTE(4) levels were associated with increased rates of pain and acute chest syndrome (ACS) episodes, when those with LTE(4) values in the highest tertile were compared with those in the lowest tertile (pain: risk ratio 7.1, 95% CI 1.8-27.5, P = 0.005; ACS: risk ratio 12.2, 95% CI 2.1-69.8, P = 0.005).

Increased expression of urinary matrix metalloproteinases parallels the extent and activity of vascular anomalies

OBJECTIVE

Matrix metalloproteinases (MMPs) and the angiogenic proteins basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have been implicated in mechanisms of human cancer and metastasis. Assays were conducted on the urine of patients with vascular anomalies (tumors and malformations), relatively common and occasionally life-threatening disorders for which few therapies exist. We sought to determine whether these angiogenesis modulators are present in the urine and whether their expression is associated with the extent and clinical course of the vascular lesion.

METHODS

A total of 217 patients with vascular anomalies and 74 age-matched control subjects participated. Urinary MMP expression was determined by substrate gel electrophoresis. Urinary bFGF and VEGF levels were measured by enzyme-linked immunosorbent assay. Each patient was assigned to 1 of 2 categories (tumor or malformation) and 1 of 9 specific groups. Extent of the vascular lesion and activity were scored by a blinded clinician.

RESULTS

Urinary high molecular weight (hMW) MMPs and bFGF were significantly increased in patients with vascular tumors (53%) and vascular malformations (41%), compared with control subjects (22%). These percentages increased as a function of extent of the lesion and disease activity. hMW MMPs were increased in 4 groups: infantile hemangioma, other vascular neoplasms, lymphatic malformation and capillary-lymphaticovenous malformations, and extensive and unremitting capillary malformation and arteriovenous malformation. No significant differences among the groups were detected for low molecular weight MMPs or VEGF.

CONCLUSIONS

Expression patterns of hMW MMPs and bFGF in the urine of patients with tumors and malformations are consistent with their different clinical behavior. These data represent the first evidence that MMPs are elevated in the urine of children with vascular anomalies. These data also suggest that the increased expression of urinary MMPs parallels the extent and activity of vascular anomalies in children. In addition to tumors, vascular malformations are angiogenesis dependent, suggesting that progression of a vascular malformation might be suppressed by angiogenic inhibitors, which would target bFGF and MMPs.

C-reactive protein and microalbuminuria differ in their associations with various domains of vascular disease

C-reactive protein (CRP) and microalbuminuria (MA) have been identified as risk markers for cardiovascular disease (CVD). We questioned whether CRP and MA are similar markers of vascular disease in different regions of the vascular tree like the heart, kidneys and extremities or if they differ in their relationships with these vascular beds. Baseline levels of CRP and urinary albumin were measured in 6669 non-diabetic participants in the Prevention of Renal and Vascular ENdstage Disease (PREVEND) study, a Dutch cohort derived from the general population. We defined three domains of vascular disease; coronary heart disease (myocardial infarction or infarct pattern on the ECG), renal insufficiency (creatinine clearance <60 ml min(-1)) and peripheral artery disease (ankle brachial index <0.9 or lower limb revascularisation). The prevalence of an elevated CRP (27.7 vs. 17.9%) and MA (17.5 vs. 10.4%) were increased in subjects with vascular disease as compared with subjects without CVD. The prevalence of an elevated CRP was equal in subjects with either coronary heart disease, renal insufficiency or peripheral artery disease (28.4 vs. 29.5 vs. 26.0%, NS), whereas MA was most prevalent in subjects with coronary heart disease (22.5 vs. 12.8 vs. 14.9%, P<0.05). Using multivariate analyses, CRP was independently associated with all three domains of vascular disease, whereas MA was independently associated with coronary heart disease only. In addition, we found synergistic contributions of an elevated CRP and older age to the risk of vascular disease in all three domains. Thus, CRP and MA are risk markers for vascular disease, each showing a different risk profiling for different vascular beds.

Aspirin dosage and thromboxane synthesis in patients with vascular disease

STUDY OBJECTIVE

To determine whether urinary 11-dehydrothromboxane B2 (d-TXB2) is a marker of aspirin resistance and define the relationship between aspirin dosage and concentrations of this thromboxane metabolite.

DESIGN

Randomized, crossover study.

SETTING

Two outpatient clinical centers.

PATIENTS

Forty-eight patients (mean age 70 yrs) with vascular disease (52% clinical coronary artery disease, 29% cerebrovascular disease, 46% atrial fibrillation).

INTERVENTION

Levels of serum thromboxane B2 and d-TXB2 were measured after patients were treated initially with aspirin 325 mg/day for 4 weeks, then again after random assignment to receive aspirin 81, 325, or 1300 mg/day for 4 weeks, and then again after resumption of 325 mg/day for 4 weeks.

MEASUREMENTS AND MAIN RESULTS

During treatment with aspirin 325 mg/day, the mean +/- SD serum thromboxane B2 level was 0.9 +/- 1.2 ng/ml and median (interquartile range) was 0.4 (0.2-0.9) ng/ml. Mean urinary d-TXB2 was 16 +/- 7.9 ng/mmol creatinine, with a median of 15 (9.9-23) ng/mmol creatinine with aspirin 325 mg/day. After 4 weeks of aspirin 81 mg/day, levels of serum thromboxane B2 (p<0.01) and urinary d-TXB2 (p=0.04) were both significantly higher compared with aspirin 325 mg/day; for urinary d-TXB2, the median increase was 3.0 ng/mmol creatinine. After 4 weeks of treatment with aspirin 1300 mg/day, levels of serum thromboxane B2 (p<0.01) and urinary d-TXB2 (p<0.01) were both significantly lower compared with aspirin 325 mg/day; the median decrease in urinary d-TXB2 was 4.4 ng/mmol creatinine.

CONCLUSION

Different aspirin dosages significantly affect serum and urinary markers of thromboxane synthesis.

Diagnosis of nut-cracker phenomenon using renal Doppler ultrasound in orthostatic proteinuria

BACKGROUND

We evaluated the efficacy of non-invasive renal Doppler ultrasound (US) to detect the nut-cracker phenomenon (NCP) and we studied the prevalence of NCP in children with orthostatic proteinuria.

METHODS

Among a total 66 cases of orthostatic proteinuria, 39 cases of NCP were found, with 27 cases being detected in a normal control group. Using Doppler US, the anteroposterior (AP) diameter and peak velocity (PV) of the left renal vein (LRV) were measured at the hilar and aortomesenteric portion. We calculated the ratio of AP and PV diameters between the two portions. The parameters were analysed using Student's t-test.

RESULTS

The AP diameters and the ratio in the hilar and narrow portions were all significantly different between the two groups (P<0.01). The PV in the narrow portion and the ratio of PV were significantly different (P<0.01), but the PV in the hilar portion was not statistically different between the two groups (P>0.05). If the diagnostic criteria for NCP was that the ratio of PV was more than 5, then 22 subjects (56.4%) in the orthostatic proteinuria group and none in the control group could be diagnosed as NCP. If, however, the cut-off values for the diagnosis of NCP were set at the mean+/-2 SD of the ratio (PV ratio 3.98 and size ratio 4.16), then the orthostatic proteinuria group showed abnormal AP diameter in 25 (64.1%), peak velocity in 28 (71.8%), and both in 21 patients (53.8%), and the control group showed an abnormal AP diameter in one subject (3.7%).

CONCLUSIONS

NCP may be one of the leading causes of orthostatic proteinuria, and non-invasive renal Doppler US may be a useful diagnostic tool in the screening of NCP. In the future, the diagnostic criteria of NCP must be redefined in children.

Chloride-sensitive renal microangiopathy in the stroke-prone spontaneously hypertensive rat

BACKGROUND

In the stroke-prone spontaneously hypertensive rat (SHRSP) fed a low-normal NaCl diet, we recently reported that supplemental KCl, but not KHCO(3) or K-citrate (KB/C), exacerbated hypertension and induced hyperreninemia and strokes. We now ask the following question: In these SHRSP, is either such selectively Cl(-)-sensitive hypertension or hyperreninemia a pathogenetic determinant of renal microvasculopathy?

METHODS

SHRSPs were randomized to either supplemental KCl, KB/C, or nothing (control) at 10 weeks of age. Four and 14 weeks afterward, we assessed renal microangiopathy histologically and measured plasma renin activity (PRA). From randomization, blood pressure was measured radiotelemetrically and continually; proteinuria was measured periodically.

RESULTS

KCl, but not KB/C, amplified renal microangiopathy and proteinuria. Four weeks after randomization, when KCl initially exacerbated hypertension, renal microangiopathy, hyperproteinuria, and hyperreninemia had not yet occurred. However, across all groups, the increment of SBP at four weeks strongly predicted its final increment, severity of renal microangiopathy, proteinuria, and PRA 14 weeks after randomization. Then, the severity of renal microangiopathy varied directly with the levels of systolic blood pressure (SBP; R(2) = 0.9, P < 0.0001), PRA (R(2) = 0.7, P < 0.0001), and proteinuria (R(2) = 0.8, P < 0.0001) as continuous functions across all treatment groups. Renal creatinine clearance was greater with KB/C.

CONCLUSIONS

In the SHRSP, (1) like cerebral microangiopathy, renal microangiopathy is selectively Cl(-) sensitive and hence, systemic microangiopathy is as well; (2) Cl(-) likely amplifies microangiopathy by exacerbating hypertension and possibly also by increasing PRA; and (3) Cl(-) might increase blood pressure and PRA by further constricting the renal afferent arteriole.

Arsenic species in drinking water, hair, fingernails, and urine of patients with blackfoot disease

A large number of residents on the southwest coast of Taiwan suffer from an endemic peripheral vascular disease called blackfoot disease. Although the etiology has been investigated since 1958, the cause of blackfoot disease remains unknown. Certain substances contained in artesian well water have been implicated as causal factors, including arsenic as the predominant element. Data in this study demonstrated that in the well water collected from blackfoot disease regions of Taiwan there was a marked increase in total arsenic concentrations, with the predominant species being inorganic arsenical compounds. The concentrations of organic methyl arsenicals were present in minimal amounts. The excretion of total arsenic, inorganic arsenic, monomethylarsonic acid, and trimethylarsenic acid in the urine of patients afflicted with blackfoot disease was significantly higher than for control subjects. Further, in patients with blackfoot disease the concentrations of total arsenic and inorganic arsenic were markedly elevated in the hair and fingernails. Data suggest that blackfoot disease is associated with individuals ingesting well, water contaminated with arsenic primarily in the inorganic form and that hair, fingernails, or urine specimens serve as equally effective biomarkers of exposure. The fact that arsenic intoxication as manifested by blackfoot disease is still prevalent despite the stoppage of well-water consumption for two decades illustrates the persistent nature of arsenic action.

1H NMR determination of urinary betaine in patients with premature vascular disease and mild homocysteinemia

Urinary N,N,N-trimethylglycine (betaine) and N,N-dimethylglycine (DMG) have been identified and quantified for clinical purposes by proton nuclear magnetic resonance (1H NMR) measurement in previous studies. We have assessed these procedures by using both one-dimensional (1-D) and 2-D NMR spectroscopy, together with pH titration of urinary extracts to help assign 1H NMR spectral peaks. The betaine calibration curve linearity was excellent (r = 0.997, P = 0.0001) over the concentration range 0.2-1.2 mmol/L, and CVs for replicate betaine analyses ranged from 7% (n = 10) at the lowest concentration to 1% (n = 9) at the highest. The detection limit for betaine was < 15 mumol/L. Urinary DMG concentrations were substantially lower than those of betaine. Urinary betaine and DMG concentrations measured by 1H NMR spectroscopy from 13 patients with premature vascular disease and 17 normal controls provided clinically pertinent data. We conclude that 1H NMR provides unique advantages as a research tool for determination of urinary betaine and DMG concentrations.

Microalbuminuria associated with diabetic neuropathy

OBJECTIVE

To test the hypothesis that microalbuminuria may show an independent statistical association with diabetic neuropathy.

RESEARCH DESIGN AND METHODS

An observational study of a prospectively identified cohort was conducted at the University Medical Center. The cohort consisted of 78 consecutive diabetic patients who fulfilled the criteria of having diabetes for greater than 10 yr, a normal serum creatinine, urine negative for macroalbuminuria by a commonly used dipstick method, a blood glucose less than 13.8 mM (less than 250 mg/dl), and an HbA1 less than 11% (normal range 5.5-8.5%). Medical record review established the presence of chronic complications of diabetes. Urine albumin level was measured by radioimmunoassay. Albumin concn greater than or equal to 15 mg/L was used as a cutoff value for microalbuminuria.

RESULTS

Twenty-five of 78 patients (32%) showed microalbuminuria. Of these, 51% had neuropathy, 39% had retinopathy, 35% arterial hypertension, 17% peripheral vascular disease, and 15% ischemic heart disease. After adjusting for age, sex, and type and duration of diabetes, diabetic neuropathy and hypertension showed a significant association with microalbuminuria. After adjusting for other diabetic complications, diabetic neuropathy showed a significant association with microalbuminuria.

CONCLUSIONS

Microalbuminuria is independently associated with diabetic neuropathy. This association lends support to the theory of a vascular etiology for diabetic distal symmetrical neuropathy.

A critical evaluation of urinary immunoreactive thromboxane: feasibility of its determination as a potential vascular risk indicator

Urinary immunoreactive thromboxane (irTXB2) has been found helpful in acute settings with altered renal, but also extrarenal thromboxane formation. As only trace amounts of systemically formed thromboxane are excreted unmetabolized, the nature of urinary irTXB2 was explored. The two most abundant metabolites of systemic thromboxane, 2,3-dinor-TXB2 and 11-dehydro-TXB2, crossreacted about 70% and less than 1%, respectively, with a widely used thromboxane antiserum. After solid-phase extraction of urine samples and separation on reversed-phase HPLC, the bulk of immunoreactivity always eluted as one peak shown to correspond to 2,3-dinor-TXB2. Much less was found in fractions where TXB2 eluted. Therefore, urines were read against calibration curves constructed with 2,3-dinor-TXB2. This direct estimation gave good recoveries for standard 2,3-dinor-TXB2 and correlated well, both in healthy controls and in patients at increased risk or with overt vascular disease, to values obtained after solid phase extraction, purification on reversed-phase HPLC and quantitation by either gas-chromatography mass-spectrometry or radioimmunoassay. Patients with multiple cardiovascular risk factors but free from detectable vascular disease excreted significantly more irTXB2 than age-matched controls with non-vascular conditions or normals. Therefore, urinary irTXB2 measured with this antiserum represents 2,3-dinor-TXB2, reflecting the systemic formation of TXB2. This simple approach is feasible for screening thromboxane formation in large series of patients. Its acumen in detecting the early development of vascular disease and its relation to established risk factors deserves large-scale prospective testing.

Urinary excretion of connective tissue protein markers in arterial disease

In diseases of major arteries there is an increased turnover of connective tissue components. This implies a greater excretion of fragments of collagen and elastin. The changes for each of these may be useful in further delineating the nature of the disease. In a preliminary study, the urine of 10 Marfan's syndrome patients was analyzed. The hydroxyproline (collagen) concentration was up to eight times higher than that of control subjects. The desmosine (elastin) crosslink concentration was either normal or slightly reduced in these patients. The mean of the ratio of hydroxyproline to desmosine was nearly seven times higher in the patients.

Microalbuminuria as predictor of vascular disease in non-diabetic subjects. Islington Diabetes Survey

The relation between urinary albumin excretion rate (AER) and vascular disease was studied in 187 subjects aged over 40 selected from 1084 cases attending a diabetic screening project. AER exceeded 20 micrograms/min in 3 of 13 newly diagnosed diabetic subjects (23%) and 16 of 171 non-diabetic subjects (9.4%). There was a weak relation between AER and both systolic and diastolic blood pressures. Coronary heart disease was found in 54 of 164 (32.9%) subjects with AER of 20 micrograms/min or less and in 14 of 19 (74%) with AER above this. Peripheral vascular disease was present in 16 of 165 (9.7%) subjects with AER of 20 micrograms/min or less and 8 of 18 (44%) with a high AER. Logistic regression, including diabetes, impaired glucose tolerance, systolic and diastolic blood pressures, smoking, age, sex, ethnic origin, and body mass index, demonstrated the independence of this relation between AER above 20 micrograms/min and coronary heart disease (odds ratio [OR] 6.38, 95% confidence interval 1.91-21.4) and peripheral vascular disease (OR 7.72, 2.14-27.8). After a mean of 3.6 (SD 0.19) years, 167 subjects (89.3%) were traced. There had been 9 deaths, 3 (2.0%) among 149 subjects with normal AER and 6 (33%) among 18 microalbuminuric subjects (OR 24.33, 5.40-109.7).

Endogenous atrial natriuretic factor in dogs with caval constriction

Chronic constriction of the thoracic inferior vena cava results in decreased filling pressure and cardiac output, in augmented secretion rates of renin and aldosterone, and in marked sodium retention with ascites and edema formation. The goal of the present study was to determine temporal changes in the plasma concentration of immunoreactive atrial natriuretic factor (iANF) in response to chronic constriction of the thoracic inferior vena cava in the conscious dog. Following constriction of the thoracic inferior vena cava, all dogs retained sodium avidly for at least 10 days, and both plasma renin activity and plasma aldosterone concentration increased markedly (p less than 0.05). Additionally, the baseline plasma iANF of 70 +/- 5 pg/ml decreased significantly to 24 +/- 7, 26 +/- 10, and 34 +/- 11 pg/ml (p less than 0.05) on days 2, 6, and 10 following thoracic inferior vena cava constriction. Thus, chronic sodium retention in this model is associated with prolonged endocrine adjustments in the circulating levels of renin-aldosterone and iANF. We suggest that chronic decreases in the secretion of atrial natriuretic factor might contribute to the inability of the dog with constriction of the thoracic inferior vena cava to excrete sodium normally.

The excretion of free cortisol, cortisone, cortisol sulfate and cortisone sulfate in peripheral vascular disease, diabetes mellitus and hyperthyroidism

In four groups of persons, 1/healthy individuals, 2/ patients with diabetes mellitus, 3/ patients with peripheral vascular disease, and 4/ patients with hyperthyroidism, the urinary excretion of free cortisol, cortisone, cortisol sulfate and cortisone sulfate was estimated. In groups 2 and 3 the excretion of all four substances was elevated. In hyperthyroidism a preponderance of free cortisone over cortisol was registered. The ratios of the followed substances suggest in patients with peripheral vascular disease a detoriation in the normal excretion of the followed corticoids, based on a preponderance of 11-OH-corticosteroids over their 11-oxo-derivatives. This observation could be implicated in the mild hyperglycemia or decreased glucose tolerance, that is often found in atherosclerotic disease.

Endocrine function in a case of beta-adrenergic hyperdynamic circulatory state

Endocrine functions were investigated in a case of "beta-adrenergic hyperdynamic circulatory state". This state was diagnosed by (1) typical symptoms of cardiac awareness, (2) physical findings (increments of pulse rate and blood pressure by changing positions or walking), (3) increase in cardiac output (5.25 l/min leads to 14.03 l/min) and decrease in circulatory time (10.8 sec leads to 5.5 sec) by isoproterenol infusion (0.02 mug/min/kg body weight), (4) rapid loss of symptoms and above findings by propranolol treatment (30 mg per os daily) and reappearance by discontinuing medication. The mechanism of insulin response to glucose has been a controversy as to whether the secretion is transmitted by beta-receptor or independent glucose receptor. And in this physiologic beta-adrenergic state, it was found that insulin responses in IVGTT and OGTT were within normal limit. When beta-adrenergic condition was corrected by propranolol treatment, insulin responses were shown lowered, though in the normal range. This could be reproduced by discontinuing medication. Insulin, glucagon and growth hormone secretions caused by arginine were also found normal, but during the period the patient was on propranolol therapy, all responses were decreased, within the normal range. These results do not positively support the idea that glucose receptor is linked to beta-receptor. They do not either agree with the contention that secretions of insulin, glucagon and growth hormone induced by arginine are mediated through beta-receptors.

Differential renal protein clearance in diabetes

Measurements of differential renal protein clearance (ratio of the renal clearance of immunoglobulin-G to that of transferrin) have been performed in long-standing diabetics with varying amounts of proteinuria. In seventy-one diabetics the IgC-transferrin clearance ratio (0.44 ± 0.04, mean ± S.E.M.) was significantly lower than in seventeen normal subjects (1.85 ± 0.24). The mean IgG-transferrin clearance ratio was significantly lower in fourteen of these diabetics with normal amounts of proteinuria than in normal subjects. A further decrease in clearance ratio was apparent when nonproteinuric (125 mg./24 hr.) and minimally proteinuric (500 mg./24 hr.) diabetics were compared. Deterioration of renal function in proteinuric diabetics was associated with an increase in the IgG-transferrin clearance ratio. The results taken overall suggest that an initial fall and a delayed rise in the clearance ratio occurs in individuals who progress to terminal renal failure. The initial fall in the IgG-transferrin clearance ratio may reflect the earliest renal changes of diabetic nephropathy. The relationship of this fall to the onset of carbohydrate intolerance remains to be clarified.