Different behaviour of the N-terminal and C-terminal fragment of proatrial natriuretic factor in plasma of healthy subjects as well as of patients with cirrhosis

N-terminal (atrial natriuretic factor (ANF) 1-98) and C-terminal (ANF 99-126) fragments of proatrial natriuretic factor (NTA and CTA, respectively) were determined in plasma of healthy subjects adopting different postures and in patients with cirrhosis. Seven healthy subjects were investigated while seated and 30 min after assuming a horizontal position. NTA plasma concentrations increased in subjects in the horizontal position (from 734 +/- 250 (SE) fmol/ml to 902 +/- 227 fmol/ml; p less than 0.05). In contrast, CTA plasma concentrations remained unchanged (9.2 +/- 1.3 fmol/ml vs 8.9 +/- 1.6 fmol/ml). In 10 patients with cirrhosis of the liver, NTA concentrations were markedly (p less than 0.001) elevated compared to 11 healthy subjects (2334 +/- 291 fmol/ml vs 743 +/- 155 fmol/ml). However, there was no difference of CTA plasma levels between cirrhotic patients and healthy subjects (8.7 +/- 1.3 fmol/ml vs 8.2 +/- 0.9 fmol/ml). These data demonstrate changes of the plasma concentration of the N-terminal fragment of proatrial natriuretic factor by posture and in liver disease, in contrast to unchanged levels of the C-terminal fragment.     

Dopamine reduces aldosterone and 18-hydroxycorticosterone response to angiotensin II in patients with essential low-renin hypertension and idiopathic hyperaldosteronism

Plasma aldosterone, 18-hydroxycorticosterone (18-OH-B), 18-hydroxydeoxycorticosterone (18-OH-DOC), corticosterone, cortisol and prolactin levels were determined during an angiotensin II infusion at increasing rates both with and without a simultaneous infusion of dopamine in seven normotensive subjects, in ten patients with essential hypertension, and in ten patients with primary aldosteronism. In a second set of experiments, maximum increases of these plasma levels were determined after metoclopramide (10 mg intravenously) in all subgroups. As compared with the other groups, an exaggerated angiotensin II-induced response of plasma aldosterone and 18-OH-B levels was observed in the five patients with low-renin essential hypertension (LREH) and in five patients with idiopathic hyperaldosteronism (IHA). Dopamine reduced the maximal increase of aldosterone and of 18-OH-B after angiotensin II to 259 +/- 48 (SEM) pg/ml and 511 +/- 152 pg/ml respectively in LREH (without dopamine: 515 +/- 74 and 908 +/- 201 respectively; P less than 0.05), and to 466 +/- 197 and 741 +/- 212 in IHA (without dopamine: 766 +/- 193 and 1264 +/- 337 respectively; P less than 0.05). The maximal increases of plasma aldosterone, 18-OH-B, and prolactin after metoclopramide (10 mg intravenously) were higher (P less than 0.01) in patients with LREH and in patients with primary aldosteronism. Plasma levels of 18-OH-DOC, corticosterone and cortisol were not affected by the stimuli applied. The exaggerated response to metoclopramide as well as to angiotensin II and its reversion only by pharmacological doses of dopamine are consistent with an increased but ineffective dopamine inhibition of aldosterone and 18-OH-B in LREH and IHA.     

Simultaneous Assay of Immunoreactive β-Lipotropin, γ-Lipotropin, and β-Endorphin in Plasma of Normal Human Subjects, Patients with ACTH/Lipotropin Hypersecretory Syndromes, and Patients undergoing Chronic Hemodialysis

We have studied the relative concentrations of the human immunoreactive (IR) peptides gamma-lipotropin (hgammaLPH, [1-58]hbetaLPH), beta-lipotropin (hbetaLPH), and beta-endorphin (hbetaEND, [61-91]hbetaLPH) using gel exclusion chromatography together with a specific radio-immunoassay (RIA) for hgammaLPH and a RIA that (because hbetaEND is the COOH-terminus of the hbetaLPH molecule) measures both hbetaEND and hbetaLPH on an equimolar basis. In normal subjects, basal plasma IR-hgammaLPH was often undetectable (<12.5 fmol/ml), but ranged up to 21 fmol/ml, and IR-hbetaEND/hbetaLPH was 10.8+/-0.7 fmol/ml; previous studies by others suggest that most of the IR-hbetaEND/hbetaLPH was probably hbetaLPH. Both IR-hgammaLPH and IR-hbetaEND/hbetaLPH were significantly elevated (P < 0.001) in patients undergoing chronic hemodialysis (101.5+/-12.7 and 23.8+/-2.0 fmol/ml, respectively). Their IR-hgammaLPH coeluted with standard hgammaLPH as a single peak, and IR-hbetaEND/hbetaLPH coeluted with hbetaLPH; no distinct peak of IR-hbetaEND was observed. In patients with ACTH/LPH hypersecretion due to Addison's disease, Nelson's syndrome, or ectopic ACTH syndrome, IR-hgammaLPH and IR-hbetaEND/hbetaLPH were both elevated, and IR-hbetaEND/hbetaLPH eluted as two peaks, one coeluting with hbetaLPH and the other with hbetaEND. The molar concentrations of all three peptides were significantly correlated with one another. The lower concentrations of endogenous IR-hbetaEND observed may be due in part to its apparent shorter plasma half-life, as estimated in an Addison's patient given a cortisol infusion. The biologic significance of these three peptides in circulating blood is still unknown. The increased levels of hbetaLPH and hgammaLPH in plasma of patients with chronic renal failure suggest that the kidney may be an important organ for their metabolism.     

Substance P, acetylcholinesterase, and beta-endorphin levels in the plasma and pericardial fluid of patients with and without angina pectoris.

We measured substance P-like immunoreactivity (SPLI), beta-endorphin-like immunoreactivity (BELI), acetylcholinesterase activity, and total protein content in pericardial fluid and plasma of patients with angina pectoris and patients with no angina pectoris. SPLI and BELI levels, acetylcholinesterase activity, and total protein content were determined by radioimmunoassay, a colorimetric method, and by the method of Lowry et al. (J Biol Chem 1951; 193:265-75), respectively. In the pericardial fluid, patients with angina had SPLI, BELI, acetylcholinesterase, and total protein values of 1.69 +/- 0.23 fmol/mg protein, 0.16 +/- 0.13 fmol/mg protein, 0.06 +/- 0.02 units, and 25.7 +/- 3.2 mg/ml, respectively. Patients with no angina had SPLI, BELI, acetylcholinesterase, and total protein values of 0.93 +/- 0.17 fmol/mg protein, 0.19 +/- 0.10 fmol/mg protein, 0.16 +/- 0.02 units, and 44.6 +/- 5.3 mg/ml, respectively. SPLI levels were significantly higher (p less than 0.03), and acetylcholinesterase (less than 0.002) and total protein content (less than 0.004) were significantly lower in the pericardial fluid of patients with angina when compared with those of patients with no angina. BELI levels were not significantly different between the two groups. In the plasma, no significant differences were found in SPLI, BELI, acetylcholinesterase, and total protein values between the two groups of patients. Patients with angina had SPLI, BELI, acetylcholinesterase, and total protein values of 0.47 +/- 0.26 fmol/mg protein, 0.06 +/- 0.06 fmol/mg protein, 0.29 +/- 0.15 units, and 68.2 +/- 8.7 mg/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Elevated CSF levels of substance P and high incidence of Raynaud phenomenon in patients with fibromyalgia: new features for diagnosis

In 30 patients with diagnosed fibromyalgia, the CSF level of immunoreactive substance P (SP) was investigated. Compared to normal values (9.6 +/- 3.2 fmol/ml), all the patients had elevated CSF levels of SP (36.1 +/- 2.7 fmol/ml, range 16.5-79.1 fmol/ml). Anamnestic information from the patients revealed that 53.3% had Raynaud/Raynaud-like phenomenon localized in the fingers, the toes or both. Although SP levels did not differ significantly in patients with or without the Raynaud phenomenon, elevated activity may be present in the peripheral branches of SP neurons which could be responsible for the last (rubor) phase of the triphasic Raynaud's phenomenon. SP levels were significantly higher in patients who were smokers (40.1 +/- 2.7 fmol/ml, range 25.3-64.1 fmol/ml), compared to patients who were non-smokers (29.2 +/- 5.0 fmol/ml, range 16.5-79.1 fmol/ml). We propose elevated CSF levels of SP and the Raynaud phenomenon as characteristic features for fibromyalgia with potential as diagnostic markers of the disease and further that smoking might be an aggravating factor for its pathogenesis or development.     

Studies of the control of plasma aldosterone concentration in normal man: I. Response to posture, acute and chronic volume depletion, and sodium loading

The peripheral plasma levels of aldosterone, renin activity (PRA), potassium, corticosterone, cortisol, and in some cases angiotensin II, were measured in normal subjects undergoing postural changes, acute diuretic-induced volume depletion, and alterations in dietary sodium. On a 10 mEq sodium/100 mEq potassium intake, subjects supine for 3 consecutive days had identical diurnal patterns of PRA, angiotensin II, aldosterone, cortisol, and corticosterone, with peaks at 8 a.m. and nadirs at 11 p.m. With an increase in sodium intake to 200 mEq, plasma levels of aldosterone and PRA fell to one-third their previous levels but the diurnal pattern in supine subjects was unchanged and again parallel to that of cortisol and corticosterone. There was no diurnal variation of plasma potassium on either sodium intake in the supine subjects. On a 10 mEq sodium/100 mEq potassium intake, supine 8 a.m. plasma aldosterone (55+/-7 ng/100 ml) and PRA (886+/-121 ng/100 ml per 3 hr) increased by 150-200% after subjects were upright for 3 hr. However, even though the patients maintained an upright activity pattern, there was a significant fall in plasma aldosterone to 33+/-5 ng/100 ml at 11 p.m. Potassium levels varied in a fashion parallel to aldosterone and PRA. Plasma cortisol and corticosterone had a diurnal pattern similar to that found in supine subjects. In response to acute diuretic-induced volume depletion, the nocturnal fall in aldosterone levels did not occur. The 11 p.m. value (102+/-20 ng/100 ml) and the 8 a.m. value postdiuresis (86+/-15 ng/100 ml) were both significantly greater than the prediuresis levels. PRA showed a similar altered pattern while potassium levels fell throughout the day. In some but not all studies, changes in plasma aldosterone coincided with changes in plasma cortisol, corticosterone, and/or potassium. However, in all studies, changes in plasma aldosterone were invariably associated with parallel changes in plasma renin activity and/or angiotensin II levels. These findings support the concept that PRA is the dominant factor in the control of aldosterone when volume and/or dietary sodium is altered in normal man.     

Elevated fasting cholecystokinin levels in pancreatic exocrine impairment: evidence to support feedback regulation

Previous studies have suggested that intraduodenal protease suppression of pancreatic exocrine secretion may be mediated through cholecystokinin (CCK) release. Our study compares basal plasma immunoreactive CCK concentrations in normal human subjects with those obtained in patients with chronic pancreatitis. Fasting plasma samples were collected from 18 normal subjects and from 18 patients with chronic pancreatitis. Eight patients had mild to moderate pancreatic exocrine impairment, and 10 had severe exocrine insufficiency. Venous plasma immunoreactive CCK concentrations were measured with two distinct peptide region-specific antibodies. Basal plasma CCK concentration in controls was 14.3 +/- 1.3 fmol/ml (mean +/- SEM), a value significantly less than that obtained in all patients with chronic pancreatitis, 30.1 +/- 4.0 fmol/ml (p less than 0.001). Patients with mild to moderate impairment had a fasting plasma CCK concentration of 32.8 +/- 7.9 fmol/ml (vs. control p less than 0.01), and those with severe disease 27.9 +/- 3.6 fmol/ml (vs. control p less than 0.001). In five patients with mild to moderate impairment of exocrine function and pancreatic extract-responsive abdominal pain, there was a 39 +/- 11% decrease in basal CCK levels during extract therapy (p less than 0.05). Results of this study indicate that pancreatic exocrine impairment is associated with elevated basal CCK levels, which may reflect a failure to provide feedback downmodulation of CCK release.     

Plasma cardiotrophin-1 following acute myocardial infarction: relationship with left ventricular systolic dysfunction.

The glycoprotein 130 (gp 130) signalling pathway is important in the development of heart failure. Cardiotrophin-1 (CT-1), a cytokine acting via the gp 130 pathway, is involved in the process of ventricular remodelling following acute myocardial infarction (AMI) in animals. The aims of the present study were to examine the profile of plasma CT-1 following AMI in humans, and its relationship with echocardiographic parameters of left ventricular (LV) systolic function. Serial measurements of plasma CT-1 levels were made in 60 patients at 14-48 h, 49-72 h, 73-120 h and 121-192 h following AMI and at a later clinic visit. LV function was assessed using a LV wall motion index (WMI) score on admission (WMI-1) and at the clinic visit (WMI-2). Compared with values in control subjects (29.5+/-3.6 fmol/ml), the plasma CT-1 concentration was elevated in AMI patients at 14-48 h (108.1+/-15.1 fmol/ml), 49-72 h (105.2+/-19.7 fmol/ml), 73-120 h (91.2+/-14.9 fmol/ml) and 121-192 h (118.8+/-22.6 fmol/ml), and at the clinic visit (174.9+/-30.9 fmol/ml) (P<0.0001). Levels were higher following anterior compared with inferior AMI. For patients with anterior AMI, CT-1 levels were higher at the clinic visit than at earlier times. WMI-1 correlated with CT-1 at all times prior to hospital discharge (P<0.05). On best subsets analysis, the strongest correlate with WMI-1 was CT-1 level at 49-72 h (R(2)=20%, P<0.05). In conclusion, plasma levels of CT-1 are elevated soon after AMI in humans and rise further in the subsequent weeks in patients after anterior infarction. CT-1 measured soon after AMI is indicative of LV dysfunction, and this cytokine may have a role in the development of ventricular remodelling and heart failure after AMI.     

Serum cortisol as a predictive marker of the outcome in patients resuscitated after cardiopulmonary arrest

OBJECTS: To analyze the relationship between stress hormones (arginine vasopressin (ADH), adrenocorticotropic hormone (ACTH) and cortisol and the outcome of patients resuscitated after cardiopulmonary arrest (CPA). METHODS: Thirty-six patients were enrolled in this study. In 36 of the resuscitated cases, 27 were non-survivors and 9 survived. The survival group was defined as cases either in a persistent vegetative state, with some disability or good recovery 1 month after return of spontaneous circulation (ROSC). The non-survival group was defined as cases who died within 1 month. RESULTS: The plasma ADH and ACTH levels and the serum cortisol levels in both the surviving and the non-surviving patients were 82.3+/-74.5 and 149.6+/-135.4 (pg/ml), 239.7+/-327.4 and 282.4+/-553.0 (pg/ml), 34.1+/-11.2 and 19.0+/-12.8 (g/ml) (mean+/-S.D., respectively). The plasma ADH and ACTH levels showed no significant difference between the two groups. The serum cortisol levels were significantly higher in survivors than in the non-survivors (P=0.029). We also used the receiving-operating characteristics (ROC) curves to evaluate the optimal cutoff value of the concentration of serum cortisol as a predictive maker of non-surviving patients. The cutoff value of 16.7 g/ml for the concentrations of serum cortisol was a 1.00 positive predictive value and a 1.00 specificity at a 0.519 negative predictive and a 0.409 sensitivity for predicting non-surviving patients. The area under the ROC curve was calculated to be 0.858 at a prevalence of 0.58. The plasma ADH levels correlated significantly and positively with the plasma ACTH levels (r=0.516, P<0.0010). CONCLUSIONS: We concluded that the serum cortisol levels were significantly higher in survivors than in non-survivors resuscitated after CPA.     

Activity of [des-Aspartyl1]-Angiotensin II in Primary Aldosteronism

This study describes the effects of [des-Aspartyl(1)]-angiotensin II ([des-Asp]-AII) on blood pressure and aldosterone production in patients with primary aldosteronism due to aldosterone-producing adrenal adenoma (APA) and idiopathic adrenal hyperplasia (IHA), and in normotensive control subjects. 10 patients with primary aldosteronism, 7 with APA and 3 with IHA, and 6 normotensive control subjects were placed on a constant 150-meq sodium diet for 4 days. [des-Asp]-AII was infused for 30 min at 6, 12, and 18 pmol/kg per min. Three groups of patients were identified on the basis of aldosterone response to [des-Asp]-AII. Group I, composed of normotensive control subjects, showed incremental increases in plasma aldosterone concentration from 6+/-1 to 14+/-3 ng/100 ml (P < 0.01) with [des-Asp]-AII infusion. Group II, composed of patients with primary aldosteronism, showed incremental increases in plasma aldosterone concentration from 33+/-8 to 65+/-13 ng/100 ml (P < 0.05) with 12 pmol/kg per min of [des-Asp]-AII. Group III, also composed of patients with primary aldosteronism, showed no increase of plasma aldosterone concentration with [des-Asp]-AII. Groups I and II showed similar percentage increases in plasma aldosterone concentration (P = NS). Group III showed significantly lower aldosterone responses than group I (P < 0.01). Group II included all patients with IHA and two patients with APA. Group III included only patients with APA. The blood pressure responses to [des-Asp]-AII of subjects in group I did not differ significantly from those of groups II or III.Thus, patients with IHA and a subgroup of patients with APA showed responsiveness to [des-Asp]-AII which was limited to adrenal cortical stimulation of aldosterone biosynthesis. This suggests that adrenal responsiveness to angiotensin is a major control mechanism in some forms of primary aldosteronism. The differential adrenal responsiveness to [des-Asp]-AII in patients with APA indicates either that there are two distinct subpopulations of APA, or that alteration in tumor response to angiotensin occurs during the natural progression of the disease history.     

Plasma bradykinin levels in human chronic congestive heart failure

Induction of congestive heart failure by high-frequency pacing has been reported to increase plasma levels of immunoreactive kinins in dogs. In the present study, we evaluated plasma bradykinin levels in human heart failure. Utilizing a recently developed method, we specifically measured plasma levels of bradykinin-(1-9) nonapeptide in 21 patients with chronic congestive heart failure [New York Heart Association (NYHA) stages III and IV). At the same time, we measured plasma atrial natriuretic peptide levels and plasma renin activity, and, as a marker of inflammation, plasma levels of tumour necrosis factor. In addition, 18 healthy subjects matched for gender and age served as normal controls. Plasma bradykinin concentrations were not higher in patients with chronic congestive heart failure (median 2.1 fmol/ml) than in healthy subjects (2.6 fmol/ml). In contrast, plasma atrial natriuretic peptide levels were clearly higher (patients, 63 fmol/ml; controls, 24 fmol/ml; P<0.0001), despite diuretic treatment and in the presence of high plasma renin activity (patients, 13.0 ng x h(-1) x ml(-1); controls, 0.3 ng x h(-1) x ml(-1); P<0.0001). Tumour necrosis factor was elevated in heart failure patients in NYHA class IV only (27 pg/ml, compared with 21 pg/ml in controls; P=0.013). Bradykinin, atrial natriuretic peptide and plasma renin activity levels were not correlated with the severity of the disease, as assessed by NYHA classification. These results indicate that a rather selective cytokine activation, without concomitant stimulation of the kallikrein-kinin system, occurs in human chronic congestive heart failure.     

Decreased density of binding sites for atrial natriuretic peptide on platelets of patients with severe congestive heart failure

1. Binding sites for atrial natriuretic peptide (ANP) with a specificity similar to that of vascular ANP receptors have been demonstrated previously in human platelets. The density of these binding sites for ANP on platelets is decreased after increased dietary sodium intake, when plasma ANP levels increase. ANP-binding sites were investigated in patients with severe congestive heart failure (CHF), a condition in which there is an increase in the concentration of ANP in plasma. 2. In 24 patients with a clinical diagnosis of functional class III-IV CHF, plasma ANP (90.3 +/- 13.4 fmol/ml, mean +/- SEM) was significantly higher (P less than 0.001) than in 16 age-matched patients without cardiac disease (15.4 +/- 2.0 fmol/ml). The density of ANP-binding sites on platelets was significantly lower (P less than 0.01) in the 24 CHF patients (6.3 +/- 0.8 fmol/10(9) cells) than in the non-cardiac patients (11.8 +/- 1.4 fmol/10(9) cells). There was no significant difference in affinity of the ANP-binding sites between both groups. There was a significant non-linear inverse correlation of the density of ANP-binding sites on platelets with plasma ANP concentration. These results could not be explained by prior receptor occupancy secondary to the elevated concentration of circulating ANP. 3. In conclusion, ANP-binding sites on platelets are decreased in patients with severe CHF and with significantly elevated concentration of ANP in plasma.     

The Effect of Liver Extract in Cultures of Megaloblastic Bone Marrow

N-terminal (atrial natriuretic factor (ANF) 1-98) and C-terminal (ANF 99-126) fragments of proatrial natriuretic factor (NTA and CTA, respectively) were determined in plasma of healthy subjects adopting different postures and in patients with cirrhosis. Seven healthy subjects were investigated while seated and 30 min after assuming a horizontal position. NTA plasma concentrations increased in subjects in the horizontal position (from 734±250 (SE) fmol/ml to 9021227 fmol/ml; p<0.05). In contrast, CTA plasma concentrations remained unchanged (9.2+1.3 fmol/ml vs 8.9±1.6 fmol/ml). In 10 patients with cirrhosis of the liver, NTA concentrations were markedly (p<0.001) elevated compared to 11 healthy subjects (2334±291 fmol/ml vs 743±155 fmol/ml). However, there was no difference of CTA plasma levels between cirrhotic patients and healthy subjects (8.7±1.3 fmol/ml vs 8.2±0.9 fmol/ml). These data demonstrate changes of the plasma concentration of the N-terminal fragment of proatrial natriuretic factor by posture and in liver disease, in contrast to unchanged levels of the C-terminal fragment.     

Elevated circulating cardiotrophin-1 in heart failure: relationship with parameters of left ventricular systolic dysfunction

Cardiotrophin-1 (CT-1) is a cytokine that has been implicated as a factor involved in myocardial remodelling. The objective of the present study was to establish the relationship between circulating levels of CT-1 and measures of left ventricular size and systolic function in patients with heart failure. We recruited 15 normal subjects [six male; median age 60 years (range 30-79 years)] and 15 patients [11 male; median age 66 years (range 43-84 years)] with a clinical diagnosis of heart failure and echocardiographic left ventricular systolic dysfunction (LVSD). Echocardiographic variables (left ventricular wall motion index, end-diastolic and -systolic volumes, stroke volume, fractional shortening) and plasma CT-1 levels were determined. In patients with LVSD [median wall motion index 0.6 (range 0.3-1.4)], CT-1 was elevated [median 110.4 fmol/ml (range 33-516 fmol/ml)] compared with controls [wall motion index 2 in all cases; median CT-1 level 34.2 fmol/ml (range 6.9-54.1 fmol/ml); P<0.0001]. Log CT-1 was correlated with log wall motion index (r=-0.76, P<0.0001), log left ventricular end-systolic volume (r=0.54, P<0.05), stroke volume (r=-0.60, P=0.007) and log fractional shortening (r=-0.70, P=0.001). In a multivariate model of the predictors of log wall motion index, the only significant predictor was log CT-1 (R(2)=56%, P=0.006). This is the first assessment of the relationship between plasma CT-1 levels and the degree of LVSD in humans, and demonstrates that CT-1 is elevated in heart failure in relation to the severity of LVSD.     

Adrenal function in non-septic long-stay critically ill patients: evaluation with the low-dose (1 micro g) corticotropin stimulation test

OBJECTIVE: To investigate the adrenal function in non-septic, long-stay critically ill patients. DESIGN: Prospective, consecutive study. SETTING: General intensive care unit in a university hospital. PATIENTS: Forty-three non-septic patients with protracted critical illness. INTERVENTIONS: A morning blood sample was first obtained to measure baseline plasma cortisol. Subsequently, 1 micro g of corticotropin (ACTH, Synacthene) was injected intravenously and 30 min later a second blood sample was drawn to determine stimulated plasma cortisol. Patients having a stimulated cortisol level of at least 18 micro g/dl were defined as responders. In 36 patients, morning interleukin-6 (IL-6) was also measured. MEASUREMENTS AND RESULTS: Baseline and stimulated plasma cortisol were 16.8+/-4.1 micro g/dl and 21.2+/-5.1 micro g/dl, respectively. Interleukin-6 was high (median 39.3 pg/ml, interquartile range 24.9-86.6 pg/ml) and correlated negatively with stimulated plasma cortisol (r=-0.40, p<0.05). Of the 43 patients studied, 31 patients (72%) were responders and 12 patients (28%) were non-responders to the ACTH stimulation test. Overall, 18 patients died and 25 patients survived to hospital discharge. Non-responders had significantly higher IL-6 levels compared to responders (106+/-73 versus 48+/-42 pg/ml, p<0.05), whereas mortality rate was comparable in the two groups (50% versus 38%, p=0.74). CONCLUSIONS: Circulating plasma IL-6 levels are high during protracted critical illness, and are partially responsible for the relative adrenal insufficiency found in a subset of severely ill patients.     

Relationship of increased plasma atrial natriuretic factor and renal sodium handling during immersion-induced central hypervolemia in normal humans.

Although maneuvers augmenting atrial volume and/or stretch also augment plasma levels of atrial natriuretic factor (ANF), the role of ANF in modulating renal sodium and water handling has not been defined. Water immersion to the neck (NI) was employed to assess the ANF response to acute volume expansion in 13 seated sodium-replete normal subjects. ANF increased promptly and markedly from 7.8 +/- 1.8 to 19.4 +/- 3.8 fmol/ml, then declined to 6.3 +/- 1.4 fmol/ml after 60 min recovery. Concomitantly, NI increased urine flow rate (V) (2.0 +/- 0.6 to 7.0 +/- 0.9 ml/min; P less than 0.001) and sodium excretion (UNaV) (92 +/- 12 to 191 +/- 15 mu eq/min; P less than 0.001), and decreased PRA (-66 +/- 3%) and plasma aldosterone (-57 +/- 6%). Increases of plasma ANF ranged from less than 20% to over 12-fold. Similarly, the natriuretic response to NI varied markedly from none to 500%. There was a strong correlation between peak ANF and peak UNaV (r = 0.67; P less than 0.025), but none between peak V and peak plasma ANF (r = -0.10; P greater than 0.5). These findings suggest that an increase in plasma ANF contributes to the natriuretic response to NI, implying a physiological role for ANF in modulating volume homeostasis in humans.     

Hyperglycaemia suppresses the secretion of ghrelin,a novel growth-hormone-releasing peptide: responses to the intravenous and oral administration of glucose

Ghrelin is a novel growth hormone (GH)-releasing peptide, isolated from the stomach, which may also cause a positive energy balance by stimulating food intake and reducing fat utilization. However, whether glucose influences the release of ghrelin remains unknown. Accordingly, we examined circulating levels of ghrelin and GH in response to the intravenous or oral administration of 50 g of glucose in eight healthy humans. After the administration of intravenous glucose (50 g), the plasma ghrelin level decreased significantly from 127+/-9 to 98+/-9 fmol/ml (P<0.01), associated with an increase in plasma glucose from 85+/-3 to 357+/-19 mg/dl (P<0.01). Ingestion of 50 g of glucose decreased the plasma ghrelin level significantly from 134+/-12 to 97+/-15 fmol/ml (P<0.01), associated with an increase in plasma glucose from 93+/-3 to 166+/-10 mg/dl (P<0.01). The decrease in the plasma ghrelin level lasted for more than 30 min after recovery of the plasma glucose level. In conclusion, ghrelin secretion may be suppressed, at least in part, by an increased plasma glucose level in healthy humans.     

Primary aldosteronism: a pictorial essay

Primary aldosteronism is defined as secondary hypertension accompanied by aldosterone hypersecretion that leads to suppressed plasma renin, hypokaremia and hypertension. Primary aldosteronism occurs in 3–15% of hypertensive patients and is commonly caused by aldosterone-producing adenoma (APA) or bilateral idiopathic hyperaldosteronism (IHA). APA is usually treated by adrenalectomy, whereas IHA is best managed medically. Therefore, it is important to distinguish between unilateral and bilateral disease. Computed tomography (CT) is used to differentiate the subtypes. Even when multidetector CT is used, the detection rate of APAs of 1 cm or less is lower than 60% for the following reasons: (a) aldosterone secretion does not depend on tumor size, (b) a tumor may exist without lipid-rich cells, and (c) non-functioning unilateral adenomas are not uncommon, especially in older patients. Adrenal venous sampling is the gold standard for the differentiation of unilateral from bilateral disease in patients with primary aldosteronism. It is important to compare the laterality of aldosterone secretion by performing simultaneous bilateral blood collection 15 min following adrenocorticotropic hormone stimulation. The value of (aldosterone/cortisol)_side/(aldosterone/cortisol)_{contralateral side} provides the best discrimination between patients with and without APA.     

Primary headaches: reduced circulating β-lipotropin and β-endorphin levels with impaired reactivity to acupuncture

Eleven patients affected by common migraine (CM), eleven affected by daily chronic headache (DCH), and eight healthy volunteers were studied. Plasma levels of beta-endorphin (beta EP), beta-lipotropin (beta LPH). ACTH and cortisol were measured in basal conditions and after traditional Chinese acupuncture (TCA). Basal beta LPH and beta EP plasma levels (pg/ml) in the DCH patients (57.6 +/- 9.5 and 16.8 +/- 2.5, respectively; M +/- SE) were lower than those found in the controls (83.6 +/- 13.7 and 26.0 +/- 6.1; p less than 0.001), while those found in the CM cases showed inter-mediate values (75.3 +/- 12.0 and 24.4 +/- 5.8). ACTH and cortisol concentrations in both the CM and DCH patients were in the same range as those of the control group. TCA caused an increase in beta LPH and beta EP plasma concentrations in the control group (beta LPH: 117 +/- 16.9; beta EP: 44.1 +/- 6.7). Opioid plasma levels, however, remained unmodified after TCA in both the CM and DCH groups. ACTH plasma levels remained stable after TCA in all three subject groups. Patients suffering from primary headache are characterized by low beta LPH and beta EP plasma levels and by a poor reactivity of circulating opioids to non-stressful stimuli.