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Background — Benefits of moderate endurance training include increases in parasympathetic activity and baroreflex sensitivity (BRS) and a relative decrease in sympathetic tone. However, the effect of very intensive training load on neural cardiovascular regulation is not known. We tested the hypothesis that strenuous endurance training, like in high-performance athletes, would enhance sympathetic activation and reduce vagal inhibition. Methods and Results — We studied the entire Italian junior national team of rowing (n=7) at increasing training loads up to 75% and 100% of maximum, the latter ∼20 days before the Rowing World Championship. Autoregressive power spectral analysis was used to investigate RR interval and blood pressure (BP) variabilities. BRS was assessed by the sequences method. Increasing training load up to 75% of maximum was associated with a progressive resting bradycardia and increased indexes of cardiac vagal modulation and BRS. However, at 100% training load these effects were reversed, with increases in resting heart rate, diastolic BP, low-frequency RR interval, and BP variabilities and decreases in high-frequency RR variability and BRS. Three athletes later won medals in the World Championship. Conclusions — This study indicates that very intensive endurance training shifted the cardiovascular autonomic modulation from a parasympathetic toward a sympathetic predominance. This finding should be interpreted within the context of the substantial role played by the sympathetic nervous system in increasing cardiovascular performance at peak training. Whether the altered BP and autonomic function shown in this study might be in time hazardous to human cardiovascular system remains to be established.

Psychological stress represents a risk factor for hypertension, but mechanisms are not known in detail. In this investigation we tested the hypothesis that real-life stress conditions produce changes in autonomic cardiac and vascular regulation that might differ in magnitude. University students, a well-established model of mild real-life stress, were examined shortly before a university examination, and a second time 3 months afterward, during holiday. Autonomic cardiovascular regulation was assessed by a noninvasive approach, based on autoregressive analysis of RR interval variability (V) and of systolic arterial pressure (SAP) V. The overall level of stress in the two sessions was gauged from the elevated salivary cortisol (5.6±0.5 versus 2.4±0.2 ng/mL, P P

Glucocorticoids, the final product of HPA axis, and their receptors (GRs) on mononuclear cells are crucial mediators in the endocrine-immune interaction. An alteration in GRs involving a lower receptor affinity (Kd) for glucocorticoids has been found in a group of advanced AIDS patients, who developed Addisonian symptoms (weakness, weight loss, hypotension, hyponatremia, and intense mucocutaneous melanosis) in spite of hypercortisolism and normal or slightly elevated values of ACTH (AIDS-GR). In these patients, data for the suppression test showed decreased cortisol and ACTH suppression in response to exogenous dexamethasone. The inhibitory effect of dexamethasone on radiolabeled-thymidine incorporation in mononuclear cells from these patients was also reduced. Monocytes of AIDS-GR patients had a receptor Kd of 10.5 +/- 4.2 nmol/l that was higher than that of other AIDS patients (AIDS-C) (2.9 +/- 0.8 nmol/l) and normal subjects (2.0 +/- 0.8 nmol/l: p < 0.01). Correlations were found between plasmatic IFN-alpha and receptor Kd on monocytes of AIDS-GR (r = 0.77). Poly (i)-poly (c)-induced IFN-alpha production by monocytes was inhibited by glucocorticoids in the AIDS-C group and controls (approx. 80% in both groups): The effect was reversed by the receptor antagonist RU-486. By contrast, glucocorticoid did not inhibit IFN-alpha production in AIDS-GR group. In conclusion, levels of plasmatic IFN-alpha, a cytokine with antiviral properties, may be increased several times, and dexamethasone fails to inhibit monocytes' IFN-alpha production only in AIDS with cortisol resistance, a disturbance that confirms an important immunoregulatory role of glucocorticoids in HIV disease.

We evaluated the clinical performances of the immunoenzymometric assays for type I collagen N-terminal and C-terminal telopeptides and the HPLC assay for total deoxypyridinoline, in distinguishing between subjects with a moderately increased bone resorption rate (women in postmenopause) and subjects with normal bone resorption rate (women in premenopause). The postmenopausal group consisted of 61 women who had been in menopause for no more than 10 years, while the premenopausal group consisted of 52 healthy women with normal menstrual cycles. The biochemical markers were measured in a 24 hour urine sample and the results expressed as the molar ratio with urinary creatinine. The clinical performances were estimated by calculating the accuracy (as the area under a Receiver Operated Characteristic (ROC) curve: mean +/- SEM) and the discriminating power (as score) of each assay in distinguishing postmenopausal subjects from premenopausal subjects. Type I collagen C-terminal telopeptide, type I collagen N-terminal telopeptide and total deoxypyridinoline were significantly higher in the postmenopausal than in the premenopausal group (p < 0.01). Accuracies of these three markers ranged from 66.8 +/- 5.1% to 76.8 +/- 4.3%, while Z scores ranged from 3.54 to 5.67. Type I collagen C-terminal telopeptide, type I collagen N-terminal telopeptide and total deoxypyridinoline were not significantly different in their accuracy or discriminating power. All markers were highly correlated with coefficients of correlation ranging from 0.61 to 0.77. In summary, this study shows that 1) the immunoenzymometric assays for type I collagen N-terminal telopeptide and type I collagen C-terminal telopeptide show a high accuracy and discriminating power in distinguishing subjects with different bone resorption rate; 2) the results obtained with these immunoenzymometric assays are comparable to those obtained with the HPLC assay for total deoxypyridinoline. In conclusion our data support the use of the immunoenzymometric assays for type I collagen N-terminal telopeptide and type I collagen C-terminal telopeptide for estimating bone resorption.

Angiotensin-converting enzyme (ACE) has 2 different active sites: a C-site (in the carboxy terminal region) and an N-site (in the amino terminal part). Some ACE inhibitors have a relatively greater affinity for the C-sites, whereas others bind to the 2 sites with equal affinity. The different ontogenesis of lung and heart endothelial cells can be related to binding differences to the C- and N-sites. We labeled Ro31 – 8472, a cilazapril derivative, which has the same affinity for the 2 ACE sites. Binding of 125 I-Ro31-8472 to human left ventricle and lung plasma membranes was saturable, inhibited by ethylene diaminetetraacetic acid and displayed affinities of 360 ± 41 p M in heart and 320 ± 51 p M in lung. For captopril the Hill slope was 0.57 ± 0.03 for heart and 0.48 ± 0.05 for lung; for delaprilat, a nonsulfhydryl analogue of captopril, the slope was 0.43 ± 0.05 for heart and 0.55 ± 0.05 for lung. These drugs were characterized by biphasic competition isotherms. The Hill slope of enalaprilat was 1.01 ± 0.06 for heart and 0.93 ± 0.06 for lung, and Ro31-8472 had a slope of 0.97 ± 0.04 for heart and 0.93 ± 0.03 for lung. The affinity of ACE inhibitors with Hill slope different from unity varied according to the source of ACE; in fact, delaprilat had greater affinity for the high-affinity sites of heart than lung (pK i , 9.89 and 9.47, respectively), whereas captopril had greater affinity for the high-affinity sites of lung than heart (9.40 and 8.85, respectively). The pK i of these drugs for the second site was 7.18–7.90 for each drug in each tissue. The affinity of Ro31-8472 was similar for heart and lung, but enalaprilat had greater affinity for lung ACE (pK i = 9.21) than heart ACE (pK i = 8.76). In conclusion, different ACE inhibitors can interact with the ACE binding sites exhibiting a selectivity that varies depending on the source of the enzyme. Some drugs are site- and tissue-selective (delaprilat is C-site and heart-selective; captopril is C-site and lung-selective); other inhibitors are site- and tissue-nonselective (Ro31-8472) or site nonselective but tissue-selective (enalaprilat).

A certain number of HIV-infected patients (about 17% in our series) manifest symptoms of cortisol resistance--weakness, weight loss, hypertension, chronic fatigue and intense mucocutaneous melanosis--symptoms which are also typical of Addison's disease. The diagnosis of cortisol resistance is determined through the increased plasma and urinary cortisol values and limited increases in ACTH values. Compared with patients with primary glucocorticoid resistance, AIDS patients have no symptoms of mineral-corticoid or androgen excess, only of glucocorticoid deficiency at target tissues. Mononuclear leukocytes from these patients show receptor changes which consist of an increased receptor number and decreased receptor affinity for glucocorticoids. They also show defective glucocorticoid-induced inhibition of [3H]thymidine incorporation. Glucocorticoid-resistant AIDS patients have a characteristic persistent increase in interferon-alpha production. The inverse correlation between plasma values of interferon-alpha and the receptor affinity for glucocorticoids clearly suggests that interferon production is regulated by the glucocorticoid receptor: the smaller the glucocorticoid effect on lymphocyte cells is, the greater interferon production is. Owing to the antiviral effect of interferon-alpha, it is possible that glucocorticoid-resistant AIDS patients have greater defences against viral infection than other AIDS patients. As interferon-alpha is melanogenetic, its increased production may also explain the intense skin pigmentation found in patients with the glucocorticoid-resistance syndrome.

Data reported in the literature show in the majority of cases an increased basal cortisol level in HIV-positive patients compared with controls, although the plasma concentration of cortisol in HIV-positive patients is generally within the physiological range. It is well known that pharmacological doses of glucocorticoids are immunosuppressive, but little is known about the effects of physiological concentrations of cortisol on the immune system. If a dialogue really exists between the HPA axis and the immune system, immune responses should be modulated by physiological concentrations of cortisol, as well as pathological levels of cortisol (high as in Cushing's syndrome or low as in Addison's disease), which are known to be associated with impaired immune system responses. We suggest that in HIV-positive patients, a chronic increase in the basal endogenous cortisol levels may provoke an imbalance in cytokine production, with a decrease in the production of type 1 and an increase in that of type 2. The type 1 to type 2 shift might be synergic with the increased cortisol levels in enhancing viral replication and apoptotic phenomena, and finally in causing the progression of HIV infection.

Nimesulide, the prototype of a new class of anti-inflammatory drugs, dose-dependently decreases the production of the superoxide anion (O 2 ⨪ ) in N -formyl-methionyl-leucyl-phenylalanine (fMLP)-and in phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes. The inhibition of O 2 ⨪ ) is possibly related to its inhibitory effect on polymorphonuclear leukocyte cytosolic phosphodiesterase type IV (IC 50 = 39 ± 2 μ M), to the related increase in cAMP ( P μ M) and the subsequent increase in protein kinase A activity. In fact H-89, a specific protein kinase A inhibitor, counteracts the inhibitory effect of nimesulide on O 2 ⨪ production by fMLP and PMA. The activation of protein kinase A may prompt the phosphorylation of a number of substrates, thus inhibiting the assembly of NADPH-oxidase in the plasma membrane. Accordingly, nimesulide decreases PMA-induced assembly of NADPH-oxidase in polymorphonuclear leukocytes plasma membranes by about 35%. Protein kinase A activation may also interfere with chemotaxis. Nimesulide inhibits stimulated chemotaxis and the effect is decreased by H-89. Inhibition of phosphodiesterase type IV may explain many of nimesulide's effects.

To verify the possible contribution of beta-adrenergic receptor down-regulation to the reversal of reflex tachycardia during chronic treatment with a dihydropyridine calcium antagonist, 11 hypertensive patients were studied with noninvasive blood pressure (BP) and heart rate (HR) monitoring after a placebo period, and on the first and seventh day of felodipine administration, 5 mg twice daily. Plasma catecholamines and neutrophil beta-adrenergic receptors were measured on the first and seventh day of treatment, immediately before and 2 h after drug administration. The first administration of felodipine was followed by a significant drop in BP (peak reduction in mean BP 24 +/- 7 mm Hg), lasting 6 h and mirrored by reflex tachycardia (peak increase in HR 14 +/- 9 beats/min). On the morning of the seventh day, 12 h after the previous felodipine administration, mean BP (MBP) was 16 mm Hg lower than on the last placebo day, while HR was unchanged. The next administration of felodipine was followed by a smaller drop in BP (MBP - 15 +/- 7 mm Hg; NS vs. placebo), while reflex tachycardia was the same as after acute felodipine (HR 13 +/- 8 beats/min; p less than 0.05 vs. placebo, NS vs. acute administration). Plasma noradrenaline concentration increased after both acute and chronic administration (p less than 0.0001), and preadministration values were highest on day 7 (p less than 0.05). Neutrophil beta-adrenergic receptor density and affinity did not change either acutely or chronically. This study gives both indirect and direct evidence that beta-adrenoceptor down-regulation does not occur during repeated felodipine administration in hypertension. Reflex tachycardia is not abolished, but is reset to lower BP levels.

The prolonged use of retinoids has been reported to be associated with changes of bone biochemical markers and toxic skeletal effects. Among collagen markers, type I collagen N-telopeptide (NTx) is present in all tissues that contain type I collagen, mostly in bone and in cutaneous tissue. It is a reliable indicator of bone resorption in metabolic bone disease, but has not previously been investigated in dermatological diseases during retinoid therapy. Isotretinoin, a synthetic 13-cis-retinoic acid, is highly effective in the treatment of severe acne vulgaris. We evaluated the effect of low-dose short-term oral isotretinoin treatment on bone remodeling markers in 10 adolescents (mean age 17.8 years) affected by severe acne. We measured urinary NTx as a marker of bone resorption, alkaline phosphatase (ALP) and osteocalcin (OC) as markers of bone formation, parathyroid hormone (PTH) and metabolites of vitamin D (25OH-D3 and 1,25(OH)2D3). Clinical and laboratory tests were performed before and after three months of isotretinoin treatment at the dosage of 0.5 mg/kg/day. All patients showed a good clinical response to the treatment (7/10 marked improvement, 3/10 mild improvement). No changes were detected in serum PTH, 25OH-D3, 1,25(OH)2D3, OC and ALP, while urinary NTx concentrations were significantly reduced (p < 0.05). In conclusion, the lack of change in PTH, OC, ALP and vitamin D metabolites and the absence of increase of NTx suggest no bone effect of the isotretinoin treatment. The decrease of urinary NTx could be due to the effect of isotretinoin on the cutaneous component of type I collagen. Severe acne in the active inflammatory phase could change the levels of this marker. Thus, short-term low-dose oral isotretinoin is an effective and safe treatment for severe acne.

Objectives: To investigate the prevalence, metabolic features and risk factors of a particular pattern of fat redistribution (FR), characterized by a progressive enlargement of breast and abdominal girth associated with a wasting of the lower limbs, observed in HIV-infected women treated with combined antiretroviral (ARV) therapy. Design: Cross-sectional study. Setting: Outpatients attending the Institute of Infectious Diseases, University of Milan, Milan, Italy. Patients and methods: HIV-infected women treated with two or more ARV drugs, observed between December 1997 and February 1998. FR was confirmed by means of a physical examination and dual-energy X-ray absorptiometry (DEXA). The metabolic and endocrinological measurements in patients with FR were compared with those in FR-free women. Results: FR was observed in 32 out of 306 women (10.5%). DEXA revealed more trunk fat (P < 0.01) and less leg fat (P < 0.001) in the patients with FR than in the matched controls. There were no significant differences in laboratory test results between the two groups. All of the FR patients were taking lamivudine-containin regimens; 20 of them were also taking a protease inhibitor (PI). The association of FR with lamivudine-including regimens was statistically significant (P = 0.017). Among the patients taking lamivudine, the risk associated with treatments including PI was 1.8 (95% CI 0.8-3.8, P = 0.12). A total duration of ARV therapy of more than 1000 days was associated with a greater risk of developing FR (OR 10.8; 95% Cl 1.4-80.5; P = 0.0207), Stepwise logistic regression analyses indicated that prolonged ARV therapy and a viral load of more than 10 000 copies per ml at the beginning of the last ARV regimen were the only variables that significantly and independently correlated with the risk of FR. Conclusions: The observed body modifications are caused by a redistribution of body fat without fat loss that is apparently not associated with hyperlipidemia, altered glucose metabolism or other endocrinological disorders. The development of FR in patients receiving only reverse transcriptase (RT) inhibitors suggests the presence of a PI-independent mechanism that deserves further investigation.

Nerve conduction velocity distribution (CVD) study is a newly-developed electrodiagnostic method for detecting alterations in the composition of nerve fibres according to their conduction velocity. The presence of subclinical neuropathy was evaluated in 138 diabetic patients by CVD study of four motor nerves (external popliteal and ulnar nerves bilaterally) and two sensory nerves (median nerve bilaterally), and the data obtained were compared with standard electrophysiological parameters in the same nerve segments. CVD studies revealed an altered distribution pattern in 106 of 129 evaluable patients for motor nerves (82%) and in 67 of 115 evaluable patients for sensory nerves (58%), while standard examination gave abnormal findings in 92 of 137 patients (67%) and in 33 of 118 patients (11%), respectively. Of the patients adequately evaluated by both techniques, 21 of 129 patients (16%) revealed altered CVD data unaccompanied by slowing of maximum nerve conduction velocity, and 37 patients of 101 (37%) showed similar findings for sensory nerves. Subclinical alterations of motor and sensory nerve CVD were not significantly related to age or to metabolic control expressed as glycated haemoglobin levels; a significantly longer duration of disease was found in patients with motor and mixed subclinical neuropathy with respect to non-neuropathic patients. The CVD study allowed us to detect subclinical abnormalities of motor and sensory nerve fibres; often this is a more sensitive method than the standard electrodiagnostic study. This method can be very useful as a diagnostic tool and in research in the study of the progression of diabetic neuropathy.

Angiotensin-converting enzyme (ACE) has two enzymatically active domains: a C-domain in the carboxy terminal region and an N-domain in the amino terminal region. We based the pharmacologic characterization of these sites on the rat testis-lung model. In testis, only a truncate form of ACE is present (C-site), whereas both N- and C-sites are present in lung. In this model, captopril was shown to be N-selective and delaprilat to be C-selective. Ro 31-8472, a cilazapril derivative, and enalaprilat proved to be not site selective. We used these drugs to evaluate the affinity of C and N sites in various human tissues involved in the cardiovascular actions of ACE and used [125I]Ro31-8472 as ligand. The number and affinity of ACE binding sites were 17,680 +/- 2,345 fmol/mg protein (Kd = 0.32 +/- 0.04 nM) in lung, 560 +/- 65 (Kd = 0.36 +/- 0.05 nM) in heart, 237 +/- 51 (Kd = 0.37 +/- 0.06 nM) in coronary artery, 236 +/- 63 (Kd = 0.14 +/- 0.05 nM) in saphenous vein, and 603 +/- 121 (Kd = 0.50 +/- 0.06 nM) in mammary artery. The affinity (pKi) of captopril for the N sites ranged from 9.40 +/- 0.14 (lung) to 8.41 +/- 0.10 (coronary artery). The affinity for the C-site by delaprilat ranged from 9.97 +/- 0.15 (coronary artery) to 9.10 +/- 0.14 (mammary artery). Therefore, the affinity of C- and N-sites of ACE for ACE inhibitor (ACEI) drugs is different according to the organ involved. Because ACE is a glycosylated enzyme and glycosylation is organ dependent, we suggest that organ-specific glycosylation affects the binding characteristics of ACE inhibitors to N- or C-site of human tissular ACE.

Catecholamines are involved critically in the mechanisms of liver cell proliferation by acting on hepatic alpha-1 and beta-2 adrenoceptors. To identify the role of these receptors in human hepatocellular carcinoma (HCC), the density was examined of alpha-1 and beta-2 adrenoceptors with their affinity and coupling of beta-2 adrenoceptors to adenylate cyclase in HCC tissue and in nonadjacent/nontumor tissue from the same livers. Studies were also done on healthy livers from age-matched and sex-matched patients undergoing abdominal surgery for nonhepatic diseases. Twenty-two HCC had a decrease of about 72% in alpha-1 adrenoceptor density compared with their nonadjacent/nontumor tissue and a decrease of about 40% compared with healthy controls. Nonadjacent/nontumor tissue from HCC patients had a 125% increase in alpha-1 adrenoceptor density compared with healthy livers. Twenty-three of 24 HCC had an increase of about 180% in beta adrenoceptor density compared with their nonadjacent/nontumor tissue and healthy controls. Beta adrenoceptors were coupled to adenylate cyclase, as evidenced by a guanosine triphosphate-mediated right shift in (-)-isoproterenol competition isotherms and by cyclic adenosine monophosphate (cAMP) production after stimulation with (-)-isoproterenol. The HCC tissue yielded a larger increase in cAMP than nonadjacent/nontumor tissue and healthy controls. The authors conclude that a higher density of alpha-1 adrenoceptors in nonadjacent/nontumor tissue from HCC characterizes the "healthy" part of the liver in HCC patients and that an increase in beta-2 and a decrease in alpha-1 adrenoceptor densities characterize the tumor part of the liver in human HCC.

Brain natriuretic peptide (BNP) is a 32-amino acid peptide structurally related to atrial natriuretic peptide and predominantly secreted by myocardial ventricles. Interest in this peptide has recently increased because its concentration carries prognostic value in patients with myocardial infarction [1] , congestive heart failure (CHF) [2] , or cardiac hypertrophy [3] . The circulating concentration of BNP is also a predictor of mortality, independently of cardiovascular disease [4] . Three commercially available immunoassay methods are designed to measure the plasma concentration of human BNP: two recent nonextraction assays and an older extraction RIA. Here, we compared these three immunoassays and correlated them …

beta- And alpha 1-adrenoceptor antagonist properties of bufuralol, carvedilol, celiprolol, dilevalol, labetalol, and pindolol were investigated in human myocardium and mammary artery using binding techniques and functional studies. In myocardial membranes, beta-adrenoceptor antagonists showed monophasic competition isotherms for (125I)pindolol binding with high affinity (Ki from 1-100 nM), except for celiprolol which displayed a biphasic competition isotherm (pKi = 6.4 +/- 0.06 for beta 1- and 4.8 +/- 0.07 for beta 2-adrenoceptors). Drug interactions with alpha 1-adrenoceptors were evaluated in human mammary artery by (3H)prazosin binding and by measuring contractile responses to norepinephrine (NE). Labetalol and carvedilol showed a moderate affinity for alpha 1-adrenoceptors (pKi = 6.2 +/- 0.01 and 6.1 +/- 0.06, respectively), and inhibited NE-induced contractions (pA2 = 6.93 +/- 0.23 and 8.64 +/- 0.24, respectively). Dilevalol, bufuralol, and pindolol displayed weak effect both in binding (Ki in micromolar range) and functional experiments (pA2 = 5.98, 5.54, and 6.23, respectively). Celiprolol did not show antagonist properties up to 100 microM in functional studies, but displayed a slight affinity for alpha 1-adrenoceptors in binding studies. The data indicate that the vasodilating activity of these beta-adrenoceptor antagonists is caused in some instances by an alpha 1-adrenoceptor antagonism (labetalol, carvedilol), whereas formore » the others alternative mechanisms should be considered.« less

Beta adrenergic receptors were identified in rat myocardial left ventricle and human papillary muscle by using the antagonist radioligand 3H-dihydroalprenolol. The number (37.3 and 44.5 fmol/mg of protein, respectively in rat and man), and the KD (1.6 and 2.8 nM, respectively in rat and man) of beta receptors were not significantly fifferent. Adrenergic receptors of both beta 1 and beta 2 subtypes were found to coexist in the left ventricle. The relative proportions of the two beta receptor subtypes were determined by the use of competition radioligand selective binding and computer modelling techniques employing the subtype selective antagonists ICI 118,551 (beta 2 selective) and atenolol (beta 1 selective) in rat or metoprolol (beta 1 selective) in man. The rat left ventricle contained about 74% beta 1 and 26% beta 2 adrenergic receptors, human left ventricle papillary muscles contained about 69% beta 1 and 31% beta 2. Human and rat left ventricles contain both beta 1 and beta 2 adrenergic receptors with similar affinities. Rat might be a model for the study of human myocardial beta adrenergic receptors.

Summary Specific dopaminergic receptors were found in the calf adrenal zona glomerulosa. Specific binding, as defined by the difference in 3H-ADTN (2-amino-6,7-dihydroxy-1,2,3,4 -tetrahydronaphthalene) binding in the presence of excess dopamine was saturable and of high affinity. Binding was rapid (t1/2=3.2 min) and rapidly reversible (t1/2=1.8 min). Stereospecificity of binding to the dopamine receptor was demonstrated by the fact that (R)-sulpiride, a proposed D-1 antagonist, was 50-fold more active at displacing 3H-ADTN than (S)-sulpiride, a D-2 antagonist. Among the agonists, SK&F 38393, a putative D-1 agonist, was more active than dopaminergic ergots, D-2 agonists. A Scatchard analysis of the data revealed a Kd=2.9±0.2 nM (m±SEM) and a Bmax=39±4 fmoles per mg of protein. Binding was not affected by guanyl nucleotides, nor was it affected by sodium ion. Binding was decreased by phosphatidic acid. No modification of cAMP production was observed in the presence of dopamine or of dopamine+GTP, whereas the cells showed an increase in cAMP after ACTH or β-adrenergic stimulation. These data suggest that the dopaminergic receptor identified is not linked to adenylate cyclase, and therefore its place is not in the D-2 dopamine receptor subclass.

A decreased concentration of vasopressin (AVP) in the plasma of patients with Alzheimer's disease has been shown recently and suggests damage to hypothalamic neurosecretory cells. To verify this, osmolar and hypotension (sodium nitroprusside) stimulations on AVP release were applied. The effect of metoclopramide, a powerful stimulator of AVP, was also assessed. Patients with Alzheimer's disease released AVP normally after hypotension. However, AVP response to osmotic stimulation was altered in eight out of 10 patients, owing to low osmoreceptor sensitivity and/or high threshold. Metoclopramide increased AVP in controls but not in patients. Normal AVP response to hypotension in patients with Alzheimer's disease makes it unlikely that there is a significant anatomical loss or damage of hypothalamic neurosecretory cells. Alterations in osmoreceptor function and AVP unresponsiveness to metoclopramide point to damage in the control of AVP release in Alzheimer's disease.

The stimulatory effect of metoclopramide upon aldosterone secretion is independent of the known aldosterone-regulating mechanisms (renin, potassium, adrenocorticotropic hormone), is unrelated to its effect on prolactin and is absent when metoclopramide is directly added to isolated adrenal zona glomerulosa cells. To examine the possibility of a “humoral” mediation of aldosterone stimulation by metoclopramide, we evaluated the effect of serum of 10 normal subjects injected with metoclopramide (10 mg i.v.) on aldosterone production by collagenase-dispersed calf adrenal zona glomerulosa cells. Whereas no effect was observed with serum collected before the injection, serum collected from 5 to 30 min after the injection stimulated aldosterone production. The effect was seen 2.5 min after the injection, was significant at 5 min (P 0.05), 10,15,20 and 30 min (P 0.01). The effect disappeared 40 min after the injection, when plasma aldosterone in subjects was still elevated (P 0.01). The biological half-life of the factor ( t 1 2 ) is about 12.5 min. A significant correlation was found between the maximal aldosterone response to metoclopramide in vivo and the maximal effect of serum in vitro (r2=0.69; P 0.01). We suggest that metoclopramide stimulates aldosterone production in vivo by the increase in serum of a factor which, in turn, stimulates aldosterone and whose physiological significance remains to be evaluated.

Normal subjects and patients with adult-onset diabetes received 10 gm. of aspirin in four days. On the fourth day, the fasting serum glucose and the glucose response to oral glucose were decreased in both groups. These changes were associated with increased levels of serum insulin and pancreatic glucagon, although the glucagon responses to oral glucose were unchanged. In the diabetic patients, aspirin therapy was followed by a decreased glucose response to I.V. glucose and by the appearance of an early insulin peak, which could not be demonstrated before treatment. Aspirin did not affect the I.V. glucose tolerance in normal subjects, although it did enhance the early insulin peak. A decrease in the fasting levels of free fatty acids was noted in both groups, whereas the fasting level of triglycerides decreased only in the diabetic patients. Cholesterolemia did not change in either group. A few preliminary observations indicate that, in normal subjects, ibuprofen and ketoprofen, two other presumed prostaglandin inhibitors, did not affect fasting glycemia, glucose tolerance, or the insulin response to glucose. No changes were noted after the administration of placebo.

The antihypertensive effect of indapamide, a new thiazide derivative, has a low diuretic effect and a primary action on vascular smooth muscle. It was evaluated in a series of 20 patients with non-insulin-dependent diabetes (age range 47-75 years) who had arterial hypertension of mild to moderate degree treated with hypoglycemic agents and/or diet. Indapamide, 2.5 mg, was given as a single daily dose for 6 months. A statistically significant reduction of systolic and diastolic pressures was observed in both supine and upright positions. This decrease was significant beginning in the first month of therapy (p less than 0.001). No significant modifications of fasting glycemia, postprandial glycemia, and glycosylated hemoglobin were noted. No significant changes were observed in serum sodium, potassium, chloride, calcium, and uric acid. Indapamide is an effective and practical treatment of hypertension of mild to moderate degree in patients with diabetes. The absence of effect on glucose metabolism makes it an especially interesting drug.

On the assumption that alterations in the adrenergic system may play a role in generating ventricular tachycardia in patients with myocardial post-infarction apical aneurysm, we evaluated norepinephrine concentration, number and affinity of both beta 1 and beta 2 adrenoceptors in perianeurysmatic tissue in twelve patients operated upon for congestive heart failure and recurrent sustained ventricular tachycardia. Concentration of norepinephrine in perianeurysmatic tissue was 0.1 +/- 0.05 micrograms g-1 tissue (n = 8), this value being much lower than that found in papillary muscle (n = 10) from patients with mitral valve stenosis (0.8 +/- 0.02 micrograms g-1 tissue) (P less than 0.01). The total number of beta adrenoceptors (71.4 +/- 7.8 v. 48.0 +/- 5.1 fmol mg-1 protein; P less than 0.01) and the percentage of beta 1 subtype were found to be higher in perianeurysmatic tissue (approximately 90%) than in papillary muscle (approximately 68%). Out of twelve patients with aneurysm, beta 2 adrenoceptors had considerably decreased in three patients and were absent in the remaining nine. Decrease in the neuronally released norepinephrine associated with contrasting behaviours of beta 1 and beta 2 adrenoceptors suggests the presence of a profound alteration in the sympathetic innervation of the perianeurysmatic myocardial tissue that may contribute to the genesis of sustained ventricular tachycardia in patients with postinfarction apical aneurysm.

To investigate the role of potassium deficiency in the development of glucose intolerance during caloric deprivation, potassium balance was maintained within normality with oral potassium supplementation in a group of obese subjects who underwent protein-modified fast and the results of the study of carbohydrate metabolism (oral glucose test, insulin receptors on monocytes and peripheral glucose utilization as assessed by euglycaemic clamp) were compared with those obtained in a group of obese subjects admitted to protein-modified fast without potassium supplementation. Caloric deprivation without oral potassium supplementation was followed by a negative potassium balance and a decrease of serum potassium levels; a decrease of the peripheral levels of insulin along with an increase in insulin receptors and a striking reduction of peripheral glucose utilization were also observed. The maintenance of normal potassium balance and normal serum potassium levels with oral potassium-chloride supplementation was associated with higher peripheral levels of insulin (P less than 0.01) and improvement of peripheral glucose utilization (P less than 0.01) whereas the binding of insulin to monocytes was unchanged. The data suggest that potassium depletion during protein-modified fast causes a decrease of the peripheral levels of insulin and a resistance to insulin action at the postreceptors sites which is reversed by potassium supply.

Adrenergic receptors were identified in healthy human hepatic tissue from thirty-nine subjects undergoing elective abdominal surgery by using the specific alpha 1-antagonist [3H]-prazosin and the beta adrenergic antagonist [3H]-dihydroalprenolol ([3H]-DHA). [3H]-prazosin binding to plasma membranes was rapid, of high affinity, saturable and stereospecific with a maximal binding capacity (Bmax) of 74.1 +/- 5.5 fmol mg-1 of protein. The displacement curve for (-)-norepinephrine was better explained by a one-site binding and after addition of GTP 0.1 mM the curve was not right-shifted, suggesting the majority of alpha receptors in healthy human liver are of the alpha 1 subtype and not linked to a GTP-binding protein. [3H]-DHA binding to liver plasma membranes was also rapid, of high affinity, saturable and stereospecific with a Bmax 96.5 +/- 10.3 fmol mg-1 of protein of receptors. Computer aided analysis of the displacement curve of ICI 118,551, a subtype selective beta 2-antagonist (IC50 = 62 +/- 2 nM), indicated a one-site binding, thus, showing that beta adrenergic receptors are of the beta 2 subtype. The displacement curve of [3H]-DHA for (-)-isoproterenol was right shifted by GTP indicating that beta 2 adrenergic receptors are linked to a GTP-binding protein in human liver. These results indicate that alpha 1- and beta 2-receptors co-exist in human liver but only beta 2-receptors are linked to a GTP-binding protein.

Multidrug antiretroviral regimes in HIV-infected patients may have side effects. The most frequent side effects are changes in fat metabolism and distribution. We describe a particular pattern of fat redistribution (FR), characterized by a progressive enlargement of breast and abdominal girth and fat loss in the lower limbs, which occurs in approximately 10% of HIV-infected women treated with combined antiretroviral therapy. To elucidate the metabolic, endocrine, and immunologic consequences of the observed disturbance, we measured serum lipids, glucose, C-peptide, ACTH, plasma, urinary cortisol, and cytokines IL-2, IFN gamma, Il-4, IL-10, Il-12, and TNF alpha in 36 patients with FR and in a control group without FR. There were no significant differences in hormonal and metabolic laboratory testing between the two groups. Immunology studies showed that in vitro production of TNF alpha and IL-10 was lower and IL-12 production higher in SR patients. Whether or not such immune alterations may be reponsible or be caused by fat redistribution remains to be explained. One year after the follow up, 50% of the patients treated with triple therapy developed lipodystrophy, characterized by weight loss, face-wasting, and hyperglycemia; the remaining 50% remained unchanged. In 13 patients the 3TC withdrawal was followed by improvements of the syndrome in 50% and of lipodystrophy in about 25%. These data suggest that the FR syndrome is frequent in patients treated with 3TC and that it is associated with characteristic changes in the cytokine production.