Serotonergic control of TSH and PRL secretion in obese men

To evaluate whether the inhibitory control of TSH and the stimulatory control of prolactin (PRL) secretion exerted by endogenous serotonin was altered in obesity, 22 obese men and 10 normal controls were tested with TRH (200 micrograms IV bolus) in the presence (experimental test) and absence (control test) of the serotonergic agonist fenfluramine (60 mg PO 90 min before TRH). Control and experimental tests were also performed in seven male patients with subclinical hypothyroidism and were repeated in the same obese subjects after substantial weight loss. Basal TSH levels were similar in control and obese men. Normal TSH responses to TRH (peak less than or equal to 14 mU/L) were observed in all normal controls (mean peak +/- SE 9.8 +/- 0.6 mU/L). In contrast, obese men were divided into two groups: nine in whom the TRH-induced TSH rise was higher than normal (group I: mean peak = 16.5 +/- 0.5 mU/L) and 13 in whom it was normal (group II: mean peak = 10.6 +/- 0.7 mU/L). The hypothyroid men all had elevated basal and TRH-stimulated TSH levels. Basal PRL concentrations were similar in the normal controls and both groups of obese subjects. The PRL response to TRH was lower in both group I and group II obese men than in normal controls and was similar between group I and group II.(ABSTRACT TRUNCATED AT 250 WORDS)

Growth hormone responses to growth hormone-releasing hormone, clonidine and insulin-induced hypoglycemia in normal weight bulimic women

The growth hormone (GH) responses to GH-releasing hormone (GHRH; 1 microgram/kg BW in an i.v. bolus), clonidine (150 micrograms in a single oral dose) and insulin (0.15 IU/kg BW in an i.v. bolus) induced hypoglycemia were evaluated in 7 normal weight bulimic women with regular menstrual cycles and in 7 age- and weight-matched normal women. In addition, the effect of thyrotropin-releasing hormone (TRH; 200 micrograms in an i.v. bolus) on serum thyroid-stimulating hormone (TSH) and GH levels was measured in the same subjects. Tests were carried out in random order on the 22nd days of the following menstrual cycles. A control test with the i.v. administration of normal saline instead of drugs was carried out 2 days after the TRH test. Basal GH levels were significantly higher in bulimic women than in normal controls; despite higher GH levels, bulimic women showed normal circulating concentrations of somatomedin-C (Sm-C). Serum GH levels remained unmodified during the control test. In contrast, the administration of GHRH, clonidine or insulin induced significant GH responses in all subjects. Bulimic and normal women showed comparable responses after GHRH, clonidine or hypoglycemia. The hypoglycemic response to insulin was similar in bulimic and control subjects. The administration of TRH was unable to increase the circulating levels of GH in the normal controls, whereas it significantly increased GH concentrations in 5 of 7 bulimic women.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of the GABAergic agent sodium valproate on the arginine vasopressin responses to hypertonic stimulation and upright posture in man

In order to evaluate the possible influence of GABAergic neurotransmission on the arginine vasopressin (AVP) response to osmotic and pressure volumetric stimuli, the GABAergic drug sodium valproate was administered by mouth (200 or 400 mg 16 h, 8 h and just before tests) to eight normal men before osmotic (i.v. infusion of 0.51 , NaCl for 2 h) and orthostatic (standing upright and maintaining an orthostatic position for 20 min) tests. In both experimental conditions, the AVP rise was significantly lower in the presence than in absence of sodium valproate. The maximum AVP responses in the control orthostatic and osmotic tests were respectively 2.3 and 2.5 times higher than basal levels. When 600 mg sodium valproate was given, the maximum AVP rise in response to hypovolaemic and osmotic stimuli were respectively 1.75 and 2.1 times higher than basal value. Similar results were obtained giving 1.2 g sodium valproate. These results suggest that in man a GABAergic pathway is involved in the AVP responses to hypovolaemic and hyperosmotic stimuli.

Abnormal thyroid stimulating hormone, prolactin, and growth hormone responses to thyrotropin releasing hormone in abstinent alcoholic men with cerebral atrophy

The thyroid stimulating hormone (TSH), prolactin (PRL), and growth hormone (GH) responses to thyrotropin releasing hormone (TRH), the Wechsler Adult Intelligence Scale (WAIS) for cognitive impairment, and computed tomographic scans were evaluated in 15 nondepressed alcoholic men after 4 weeks of abstinence and in 10 normal controls. Both cognitive impairment and cerebral atrophy were found in 13 of the alcoholics. Eight alcoholics (seven with cerebral atrophy) had blunted TSH and PRL responses to TRH and a TRH-induced paradoxical increase of GH. This study demonstrates that besides affecting the TSH response to TRH, alcoholism often induces alterations of the PRL and GH secretory patterns in response to TRH. The severe brain damage caused by long-term alcoholism might be involved in the pathogenesis of these neuroendocrine alterations.

Simultaneous inhibition by pirenzepine of the GH responses to GnRH and TRH in insulin-dependent diabetics and in patients with major depression

The present study was undertaken in order to establish whether muscarinic cholinergic receptors are involved in the anomalous GH response to GnRH in men with insulin-dependent diabetes mellitus and in male patients with major depression. For this purpose, 16 male diabetics, 18 depressed men and 9 normal controls were tested with GnRH (25 micrograms iv) with and without previous treatment with the muscarinic cholinergic receptor blocker pirenzepine (40 mg iv 10 min before GnRH). Additional experiments with TRH (200 micrograms iv 10 min after pirenzepine) were performed in the same subjects and used for comparison between responders to TRH and GnRH. The administration of GnRH stimulated GH release in 12 out of the 16 diabetics and in 8 out of the 18 depressed patients, but not in the normal controls. Control and diabetic non-responders to GnRH did not respond to TRH. In contrast, all diabetic responders to GnRH, except 2, showed paradoxical GH responses to TRH. All depressed responders to GnRH and 3 of the non-responders, were responsive to TRH. The pattern and magnitude of the secretory responses to TRH and GnRH were similar in depressed and diabetic patients. When the effects of GnRH and TRH were restudied in the presence of pirenzepine, neither GnRH nor TRH enhanced the serum concentrations of GH in any patient. These data indicate that a muscarinic cholinergic mechanism is involved in the anomalous responses of GH to GnRH and TRH in diabetic men and in male patients affected by major depression.

Dopaminergic, but not cholinergic, involvement in regulation of hypoglycemia-induced oxytocin release in man

The plasma oxytocin response to insulin-induced hypoglycemia was evaluated in 20 normal male subjects in the basal state (insulin tolerance test (ITT) alone) and after pretreatment with the muscarinic antagonist pirenzepine (40 mg IV 10 min before the ITT in six subjects), the nicotinic antagonist trimethaphan (0.3 mg/min IV for 30 min before the ITT in six subjects), and the dopaminergic receptor agonist bromocriptine (2.5 mg PO 1 hr before the ITT in eight subjects). The drugs did not modify arterial blood pressure nor produce side effects capable of altering oxytocin secretion. Neither pirenzepine nor trimethaphan administration changed the oxytocin response to hypoglycemia, whereas bromocriptine significantly reduced the oxytocin increase during the ITT. These data suggest the involvement of dopaminergic, but not of cholinergic, muscarinic or nicotinic, receptors in the oxytocin response to hypoglycemia.

Prevalence of migraine and muscle tension headache in depressive disorders

This study was undertaken in order to evaluate the prevalence of headache and its subtypes (migraine, muscle tension headache, cluster and psychogenic headache) in a population of 160 depressed patients. Headache was present in 83 subjects (51.9%); 36 (22.5%) were affected by migraine, 39 (24.4%) by muscle tension headache, six (3.7%) by psychogenic headache and two (1.2%) by cluster headache. No significant differences in the prevalence of migraine and muscle tension headache were observed among patients with major depression, bipolar depressive disorder and dysthymic disorder. These data speak against a specific correlation among subtypes of headache and depressive disorders.

Dopaminergic control of TSH secretion in endogenous depression

To evaluate whether the inhibitory control exerted by endogenous dopamine on thyroid-stimulating hormone (TSH) secretion is altered in patients with major depressive disorder, 11 depressed patients and 9 normal controls were tested with the dopaminergic receptor antagonist domperidone (10 or 20 mg i.v.). The administration of domperidone induced a significant increase in circulating TSH levels in the normal controls, but not in the depressed patients. These data excluded the possibility that the dopaminergic inhibition of TSH secretion is enhanced in depression. To establish whether domperidone failure was due to a reduced dopaminergic tone, domperidone was administered before stimulation of TSH secretion with thyrotropin-releasing hormone (TRH) (200 micrograms i.v.). The TSH response to TRH was significantly lower in the depressed than in the control subjects, regardless of domperidone priming. However, in both groups domperidone enhanced the TRH-induced TSH release by 50%. These data suggest that the dopaminergic control of TSH secretion is not altered in patients with endogenous depression and that a reduced capacity of the pituitary to secrete TSH might be responsible for the reduced TSH responsiveness to TRH and domperidone.

Effect of lysine vasopressin on basal and TRH stimulated TSH and PRL release in normal men

In order to test the possible effects of lysine vasopressin (LVP) on basal and TRH stimulated TSH and PRL release, an iv bolus of LVP (0.06 IU/kg bw) was injected alone or just before TRH (20 or 400 micrograms iv) in 18 normal male subjects. The administration of LVP modified neither the basal secretion of TSH and PRL nor the TSH and PRL release induced by 20 or 400 micrograms TRH. These data suggest that in humans, vasopressin is not involved in the control of TSH and PRL release at the anterior pituitary level.

Metergoline, naloxone, and sodium valproate did not modify arginine vasopressin response to insulin-induced hypoglycemia in man

The present study was carried out in order to determine whether insulin-induced hypoglycemia exerts its stimulatory effect on plasma concentrations of arginine vasopressin (AVP) by interacting with a serotonergic, a GABA-ergic or an opioid pathway. For this purpose, the effect of the serotonergic antagonist metergoline (10 mg/day for 4 days po), the GABA-ergic agonist sodium valproate (600 mg in three divided doses po) and the opioid-receptor blocker naloxone (10 mg in a iv bolus) on the AVP response during an insulin (0.15 IU/kg bw) tolerance test (ITT) was evaluated in three groups of 6 normal men each. In all men, control ITTs were performed without drug treatments. Basal and ITT-stimulated AVP secretion was not modified by drug administration, suggesting that serotonergic, GABAergic and naloxone-sensitive opioid receptors are not involved in the regulation of AVP secretion in response to insulin-induced hypoglycemia.

[Methods of the elaboration of data of the cardiological importance]

This paper deals with some introductory topics of signal processing and decision making in cardiology. In both instances the matter is referred to general schemes well suited to host different applications. Signal processing is divided in some phases: acquisition, storing, analysis and each of them is described with applications to specific signals. In a similar manner the methods for decision making have been simplified to a scheme including a "knowledge base" and an "inference method". The scheme is used to classify various implementations. Bayes analysis and expert systems have been introduced with some details.

[Analysis of the market and future trends of the instrumentation for ambulatory electrocardiography]

An inquiry has been made among most manufacturers of ambulatory ECG instrumentation. Both playback and real time systems have been considered. The inquiry, based on a questionnaire, was mainly aimed at identifying possible standard technical solutions emerging from the analysis of various implementations, and at verifying whether techniques for performance evaluation are in common use. Main conclusions of this study include: playback systems are still in competition with real time systems; automatic analysis has not yet reached adequate accuracy; analysis of ST-T interval, while performed by most systems, is not evaluated because common standard of quality is lacking.

[Ambulatory electrocardiography in patients with angina pectoris]

In the diagnosis of ischemic heart disease, long-term ECG recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, reveals the possible ischemic genesis of arrhythmias, and it is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In spite of these advantages, Holter monitoring has several limitations: the analysis of a single lead, is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours may not be sufficient for screening patients due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking even if the European Communities concerted action in Ambulatory Monitoring could represent the solution to this problem. Nevertheless the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

[Recording of signals in ambulatory electrocardiography]

The different techniques for the acquisition of electrocardiographic signal in ambulatory monitoring are described in this paper. Direct and, frequency modulation systems are explained in details with their relative advantages and disadvantages. The basis of digital sampling and real time analysis of ECG signals are also explained.

Oxytocin enhances thyrotropin-releasing hormone-induced prolactin release in normal menstruating women

The effects of oxytocin (OT) on basal thyrotropin-releasing hormone (TRH)-stimulated thyrotropin (TSH) and prolactin (PRL) secretion were evaluated in normal menstruating women during follicular, periovulatory, and luteal phases. Two different studies were performed. In one study, 15 subjects were treated with OT or saline; in the other study, 20 women were tested with TRH alone or in combination with OT. Results during follicular, periovulatory, and luteal phases were similar. OT did not produce any effect on basal serum TSH and PRL levels and on the TRH-stimulated TSH secretion, whereas it significantly enhanced the PRL response to TRH. At all examined phases during the menstrual cycle, the mean peak PRL response was reached within 20 minutes after TRH injection, and the peak was about three times higher than basal value when TRH was given alone and about four times when OT was present. These data suggest that in normal women OT is not involved in the control of basal and TRH-stimulated TSH secretion and of basal PRL release. In contrast, the enhancement of the TRH-induced PRL release suggests that OT plays a role in the control of the acutely stimulated PRL secretion. Because results were similar regardless of the phase of the menstrual cycle, estrogen and/or progesterone do not appear to be involved in the effect of OT on the TRH-induced PRL release.

Involvement of a dopaminergic mechanism in the response of growth hormone to thyrotropin releasing hormone in patients with major depression

In an attempt to establish whether, in patients with major depression, dopaminergic receptors are involved in the release of growth hormone (GH) induced by thyrotropin releasing hormone (TRH), eleven subjects were tested with TRH (200 micrograms in an i.v. bolus) with or without concomitant treatment with domperidone (10 mg in an i.v. bolus 10 min before TRH), an antidopaminergic agent which does not readily cross the blood-brain barrier. In 7 out of the 11 patients, TRH strikingly increased GH levels (responders) (the mean peak level was 9 times higher than basal value), whereas it was without effect in the remaining 4 patients (non-responders). When the responders were treated with domperidone before TRH injection, TRH-induced GH increase was still present, but it was significantly lower (the mean peak level was 5.3 times higher than basal value) than in the TRH test (p less than 0.02). These data suggest that the paradoxical response of GH or TRH in patients with major depression involves a dopaminergic mechanism active at sites situated outside the blood-brain barrier.

Lysine-vasopressin does not affect basal and LH-RH-stimulated LH and FSH release during the menstrual cycle of normal women

In order to test possible effects of lysine-vasopressin (LVP) on basal and LH-RH-stimulated LH and FSH release, an intravenous bolus of LVP (0.06 IU/kg body weight) was injected alone or 10 min before LH-RH (100 micrograms i.v.) in 33 normal women in the follicular, periovulatory and luteal phase of their menstrual cycle. The administration of LVP modified neither the basal secretion of the gonadotropins nor the LH-RH-induced LH and FSH release. These data suggest that in humans, vasopressin is not involved in the control of gonadotropin release at the level of the anterior pituitary.

Muscarinic cholinergic and histaminergic H1 and H2 receptors are not involved in the LH response to naloxone in man

The role of muscarinic-cholinergic and H1-, H2-histaminergic receptors as possible mediators of the LH response to the opioid antagonist naloxone was evaluated in 18 normal men. Subjects were divided in 3 groups of 6 men; the increment of LH in the plasma elicited by naloxone was evaluated after giving naloxone alone or together with dexchlorpheniramine, cimetidine or pirenzepine (respectively H1-, H2-histaminergic and muscarinic-cholinergic receptor antagonists). LH release was significantly stimulated by naloxone in all subjects; this response was not altered by histaminergic or cholinergic blockade. These results confirm the stimulatory effect of naloxone on LH release in man, without evidence of the involvement of H1-, H2-histaminergic or muscarinic-cholinergic pathways.

Pirenzepine inhibits growth hormone, but not thyrotropin response to thyrotropin-releasing hormone in patients with endogenous depression

In order to evaluate whether in endogenous depression the anomalous growth hormone (GH) response to thyrotropin-releasing hormone (TRH) is mediated by muscarinic cholinergic receptors, 12 patients were tested with TRH (200 micrograms iv) with and without previous treatment with the muscarinic cholinergic receptor blocker pirenzepine (40 mg iv 10 min before TRH). Control tests with normal saline also were performed. Administration of normal saline did not alter serum GH levels. In contrast, TRH injections significantly increased serum GH concentrations by about three-fold. This response was inhibited by pretreatment with pirenzepine. Another neuroendocrine marker of endogenous depression, the low TSH increase in response to TRH (delta less than or equal to 7 microU/ml), was observed in our patients. Pretreatment with pirenzepine did not modify this response. These data indicate that in patients with endogenous depression a muscarinic cholinergic mechanism is involved in the GH response but not in the TSH response to TRH.

Prognostic value of ventricular arrhythmias and transient ST-T changes after myocardial infarction: a two-year follow-up with ambulatory ECG recording

The aim of this study is to evaluate the frequency and prognostic significance of ventricular arrhythmias (VA) and of ST-T changes found during 24-h ECG recording in patients who survived an acute myocardial infarction. Eighty-nine patients (2 females and 87 males) discharged from hospital after acute myocardial infarction were studied. Mean age was 52.2 years (SD +/- 10) with a range of 26-68. Serial observations were carried out at 1, 2, 3, 6, and 12 months after the acute event. Eight patients died during the first two years of follow-up, of these, 2 deaths were of noncardiac origin: one was due to gastric carcinoma and the other to pulmonary neoplasm. Of the 6 cardiac deaths, 4 were sudden and unexpected and 2 were due to reinfarction. Statistical analysis of the results obtained in the first three months of follow-up has not shown any significant correlation between pathologic patterns and cardiac death. In the second period we found a statistically significant relationship between cardiac death and multiform VPBs (p less than 0.05), CVA (p less than 0.05), and ST-T changes (p less than 0.05). More significant was the correlation between cardiac death and the presence at the same time of ST-T changes and multiform VPBs (p less than 0.01).

Different effects of metoclopramide and domperidone on arginine-vasopressin secretion in man

This study was performed in order to investigate the dopaminergic mechanism involved in the control of arginine-vasopressin (AVP) secretion in normal men. Plasma AVP concentrations were measured before and after the administration of an i.v. bolus of 10 mg metoclopramide or domperidone to twelve healthy males. Metoclopramide, a cerebral and peripheral antagonist of dopaminergic receptors, significantly stimulated AVP secretion, whereas domperidone, a dopamine antagonist which does not cross the blood-brain barrier, was without effect. These data suggest that metoclopramide stimulates the release of AVP by blocking dopaminergic receptors in structures located inside the blood-brain barrier. Alternatively, it is possible that the stimulation of AVP release induced by metoclopramide does not occur through inhibition of dopamine receptors but rather through interaction with other neuroendocrine pathways.

Electrocardiographic monitoring: temporal versus spatial information and data processing

In the diagnosis of ischemic heart disease, long-term electrocardiographic recording has several distinct advantages. It allows one to relate patient symptoms to cardiac disturbances and to detect asymptomatic events, furnishes the whole spectrum of electrocardiographic alterations accompanying ischemic attacks, reveals the possible ischemic genesis of dysrhythmias, and is the most suitable method to assess the acute and chronic effectiveness of treatment and the evolution of the disease. In addition to its valuable application in the screening and follow-up of ambulatory patients, its use in the Coronary Care Unit is of great interest, being in this context much more sensitive than visual electrocardiographic monitoring. In spite of these advantages, Holter monitoring has several limitations: the recording and replay systems are below recommended standards; the analysis of a single lead is responsible in most systems for the low sensitivity in detecting ischemia occurring in unexplored regions; the period of 24-48 hours, usually adopted for Holter monitoring, may not be sufficient for screening patients with suspected myocardial ischemia due to the unpredictable spontaneous variability of the disease; a common standard of analysis is still lacking and a reliable computerized analysis is needed to manage data overflow. In conclusion, although further research and technical developments are desired to improve reliability and data processing, the role of Holter monitoring appears essential in the ambulatory screening of patients with suspected ischemia for a better characterization of patients with ascertained myocardial ischemia, and for the evaluation of treatment and of the evolution of the disease.

Clinical application of monitoring techniques: hemodynamic monitoring

In the diagnosis of myocardial ischemia continuous hemodynamic monitoring may contribute to detection of transient ischemia, to definition of location and to elimination of its pathogenesis, and to characterization of hemodynamic response to ischemia. It can be helpful in investigating the significance of negligible, non specific and/or short-lasting electrocardiographic changes accompanying typical anginal symptoms. Simultaneous right ventricular and left ventricular pressure monitoring gives information regarding biventricular interaction during episodes of transient ischemia: an early left ventricular dysfunction, with or without a late right ventricular impairment, a selective right dysfunction, and a simultaneous left ventricular and right ventricular impairment all represent the hemodynamic patterns associated with left, right and biventricular ischemia respectively. Monitoring of hemodynamic parameters related to myocardial oxygen consumption and the study of their changes preceding the onset of ischemia during both spontaneous and provoked episodes of ischemia, may help in identifying whether functional or organic factors or both are involved in the pathogenesis of transient ischemia in individual patients. Two principal hemodynamic patterns appear to be associated with transient ischemia: a) left ventricular and/or right ventricular impairment, usually beginning shortly before the onset of electrocardiographic changes, followed by a rapid recovery and often an overshooting, b) a sudden and sustained increase in systolic pressure and heart rate, simultaneous with the onset of ST-T changes. In both cases, the 'excitatory' pattern appears to be unrelated to pain.(ABSTRACT TRUNCATED AT 250 WORDS)

The European Community concerted action on ambulatory monitoring

The diffusion of instruments for ambulatory monitoring is rapidly expanding and the related cost to the European Community is increasing, while their role and their effectiveness are still controversial. The Biomedical Engineering Group, belonging to the Committee for Medical Research of the European Community, has approved a project for the co-ordination of the research ('concerted action') in the field of ambulatory monitoring, to tackle the problem. The project, directed by a Project Management Group, following some meetings of experts being organized to identify high-priority goals, has been aimed at promoting common efforts in two specific fields: evaluation of the quality of ECG ambulatory monitoring analysers, by means of a standard reference, and assessment of the performance of non-invasive techniques for arterial blood pressure ambulatory monitoring. In its first six months (July-December 1985) the project has produced: (1) a preliminary agreement about ECG recording and an annotation scheme, to be definitely adopted, after a pilot experiment, by June 1986; (2) a protocol for hypertensive patient characterization and data collection, to be initiated by September 1986.