Direct comparison of early elevations of cardiac troponin T and I in patients with clinical unstable angina.

BACKGROUND: The aim of this study was to compare the prognostic efficacy of cardiac troponin T (cTnT) and I (cTnI) in patients with clinical unstable angina. METHODS: We studied 74 patients with chest pain at rest, electrocardiographic evidence of myocardial ischemia, and normal (<6.7 ng/mL) values of creatine kinase-MB. cTnT was measured with a commercial assay (cutoff level 0.1 ng/mL) and cTnI with a preliminary research application (cutoff level 3.1 ng/mL). All patients had blood drawn at baseline and 8 hours thereafter. The prospectively defined end point was the proportion of patients identified by each assay as having myocardial damage. RESULTS: cTnT and cTnI were elevated in the same percentage of patients (18 of 74; 24%). Overall, 23 patients had elevations of 1 or both markers. In 13 there were elevations of both. Ten patients had elevations of only one (5 for each marker). In 51 patients, no elevations were present. Death or nonfatal myocardial infarction was more frequent in patients with elevated cTnI (27.7% vs 5.3%; P =.02) than those with normal values. The prognostic influence of cTnT was less (17% vs 8.5%; P =.2). However, the difference between the 2 markers when compared directly was not statistically significant (27.7% vs 17%; P = NS). CONCLUSIONS: These data indicate that both markers identify myocardial damage in equal numbers of patients with clinical unstable angina. Patients with elevations had a worse short-term outcome. The significance of the minor differences in prognostic value will require additional studies.

New markers for early diagnosis of acute myocardial infarction.

The availability of 'new' biochemical markers of myocardial injury such as creatine kinase isoforms and troponins has renewed the interest for rapid confirmation/exclusion of myocardial infarction in patients presented to the hospital for suspected acute myocardial ischemia. Many of these protein markers have the potential to allow the diagnosis of acute myocardial infarction at a time from the onset of symptoms when the activity of creatine kinase MB is still within the reference range. However, the exclusion of classical myocardial infarction as defined by WHO criteria does not allow to conclude that the patient is at low-risk and can be safely sent home since he may have high-risk unstable angina. The sensitivity for the detection of myocardial damage of troponins is such that a substantial proportion of patients with unstable angina develop elevations of troponins in the absence of creatine kinase MB increases. It is now clear that such patients have an increased risk of cardiac events over the short and long-term similar to that of patients with definite myocardial infarction. Such finding may help in developing selective admission policies and deciding which patients deserve aggressive treatment.

The effects of galanin on growth hormone secretion in children of normal and short stature.

We have evaluated the effect of galanin (Gal), a newly identified hypothalamic peptide, on growth hormone (GH) secretion in 10 children with normal stature (NS), nine with constitutional growth delay (CGD), and five with isolated GH deficiency (IGHD). Gal was infused intravenously at a rate of 8 or 15 micrograms/kg/h. All children also underwent an acute oral clonidine test (0.15 mg/m2). In CGD children the mean plasma GH peak after 8 micrograms/kg/h of Gal infusion (13.3 +/- 1.7 ng/mL; mean +/- SEM) was higher (p less than 0.02) than in NS children (8.5 +/- 0.8 ng/mL). When the dose of Gal was increased to 15 micrograms/kg/h the mean plasma GH peak in CGD children (18.5 +/- 3.5 ng/mL) was still higher than in the NS group (13.2 +/- 2.9 ng/mL), although not significantly so. In IGHD children the mean plasma GH peak elicited by 8 or 15 micrograms/kg/h of Gal (3.8 +/- 0.7 and 3.9 +/- 0.5 ng/mL, respectively) was lower than that obtained in either CGD (p less than 0.0002) or NS children (p less than 0.001). In NS children the mean plasma GH peak after acute clonidine administration (22.3 +/- 3.0 ng/mL) was higher than that observed after either dose of Gal used (p less than 0.001 and p less than 0.05 with 8 and 15 micrograms/kg/h, respectively). In CGD or IGHD children mean plasma GH peak after acute clonidine (14.8 +/- 2.6 and 4.1 +/- 1.2 ng/mL, respectively) was not significantly different from that observed after either dose of Gal.(ABSTRACT TRUNCATED AT 250 WORDS)

Pyridostigmine counteracts the blunted growth hormone response to growth hormone-releasing hormone of obese children.

We have evaluated the effect of acute administration of pyridostigmine bromide, a cholinesterase inhibitor, on the GHRH-induced GH rise in 11 obese children and in 8 age-matched controls. The GH response to GHRH (hpGRF 1-40, 1 microgram/kg iv), evaluated both as maximum GH peak and as integrated area under the curve, was significantly lower in the obese children than in the controls. Pretreatment with pyridostigmine bromide (60 mg orally 60 min before the GHRH injection) significantly increased both baseline GH levels and the GH response to GHRH in all the obese subjects, so that their mean baseline GH, peak GH levels and integrated area under the curve after pyridostigmine bromide plus GHRH were similar to those of the control children after GHRH. Also in control children pyridostigmine bromide increased (though not significantly) baseline GH levels. and caused a significant augmentation of the GH response to GHRH. Mean peak GH levels and mean integrated area under the curve after pyridostigmine bromide plus GHRH were significantly higher in the controls than in the obese children given the same treatment. Mean baseline Sm-C levels were significantly higher in the obese than in control children. These data show that enhancement of cholinergic neurotransmission, likely in the hypothalamus, counteracts the blunted GH response to GHRH present in the obese children, and that in simple obesity the potential of the pituitary to make a secretory response to a direct GH secretagogue is preserved.

Augmentation of growth hormone secretion in children with constitutional growth delay by short term clonidine administration: a pulse amplitude-modulated phenomenon.

We evaluated the effect of chronic clonidine administration on 24-h integrated GH secretion (IC-GH) in eight children (six boys and two girls; age, 6.0-13.0 yr) with constitutional growth delay (CGD). Clonidine was given orally in a daily dose of 0.1 mg/m2 at bedtime for 6 months; 24-h secretion studies were performed before and after 2 months of treatment. Clonidine caused a significant augmentation (P less than 0.02) of mean IC-GH from 2.6 +/- 0.4 (+/- SE) to 4.6 +/- 0.6 micrograms/L. The increase in IC-GH was mainly the result of increased GH pulse amplitude, which rose from 12.3 +/- 1.3 to 18.2 +/- 2.1 micrograms/L (P less than 0.01). The mean GH pulse amplitude was significantly higher (P less than 0.02) during sleep (15.9 +/- 2.4 micrograms/L) than during the awake hours (8.4 +/- 1.5 micrograms/L) before treatment. During clonidine treatment the mean GH pulse amplitude during the awake hours (15.0 +/- 3.8 micrograms/L) was similar to that during sleep (20.3 +/- 3.1 micrograms/L). GH pulse frequency was not altered by treatment during either the awake or sleep hours. The mean insulin-like growth factor I levels after 2 (1400 +/- 300 U/L) and 6 (1760 +/- 430 U/L) months of treatment were significantly higher (P less than 0.02 and P less than 0.05, respectively) than the pretreatment value (920 +/- 240 U/L). After 2 months of clonidine treatment, growth velocity increased from 3.1 +/- 0.5 to 10.2 +/- 1.0 cm/yr (P less than 0.001), and after 6 months of treatment is was still significantly higher (7.0 +/- 0.7 cm/yr; P less than 0.02) than that before treatment. These results confirm the ability of clonidine to accelerate growth in children with CGD and indicate that clonidine is capable of increasing IC-GH levels. They also reinforce the view that many children with CGD have decreased endogenous GH secretion.

Clonidine treatment for short stature.

34 pubertal children with constitutional growth delay (CGD) were treated with clonidine orally twice a day. In 25 of the children the height velocity rose on clonidine treatment, and in 21 of them by more than 2 cm/yr during the first 6 months of treatment (mean [SD] growth increment 4.4 [0.5] cm/yr). Of the 22 who were treated for 12 months the increment in height velocity was maintained in 13 (3.4[0.4] cm/yr). Withdrawal of clonidine for 6 months did not stop the stimulatory effect of the drug on linear growth in 6 children, but in the other 8 children height velocities fell to pretreatment levels or below. In a few children reinstitution of clonidine for 2-4 months resulted in a new increment in height velocity. A high height standard deviation score and low growth velocity before treatment were predictive of a good growth response to clonidine. Clonidine did not induce noticeable side-effects. It may be a useful form of therapy for children with CGD.

The effect of oxandrolone on the growth hormone response to growth hormone releasing hormone in children with constitutional growth delay.

The effect of treatment with oxandrolone, an anabolic steroid, on GH response to GH-releasing hormone (GHRH) has been evaluated in children with constitutional growth delay. Five subjects, four males and one female, aged 11.0-17.1 years were given oxandrolone 0.1 mg/kg p.o. daily for 2 months, and underwent acute administration of GHRH (GRF 1-40, 1 microgram/kg i.v.) before and after withdrawal of oxandrolone therapy. GHRH administration induced a much greater GH response, evaluated either as a peak plasma GH levels or plasma GH integrated area, after than it did before oxandrolone treatment. These findings indicate that in children with constitutional growth delay oxandrolone increases the sensitivity of somatotrophs to exogenous GHRH and, likely, to the endogenously-released neurohormone.

Growth hormone response to hpGRF-40 in different forms of growth retardation and endocrine-metabolic diseases.

The effect of one of the new human pancreatic growth hormone releasing factors (hpGRFs) was assessed in children or young adults with different forms of growth retardation or endocrine-metabolic diseases. Intravenously administered synthetic hpGRF-40 (1 microgram/kg) induced a clear-cut and prompt rise in plasma growth hormone (GH) levels in 8 normal prepubertal children and a definite GH rise in 11 out of 14 children with isolated GH deficiency (IGHD) and one child with the Silver-Russel syndrome. In two out of three subjects with craniopharyngioma hpGRF-40 did not induce any plasma GH increase. In seven out of ten children with constitutional growth delay (CGD), hpGRF-40 induced a biphasic GH response, with a prompt small GH increment followed by a second, more consistent rise. Both in children with IGHD and with CGD the rise in plasma GH following hpGRF-40 was markedly lower than in controls. In children with CGD the GH response to hpGRF-40 was defective, despite the fact that in most of them the GH response to standard pharmacological stimuli was normal according to generally accepted criteria. hpGRF induced a small but sustained plasma GH rise in four hypothyroid subjects, while in three out of four children with idiopathic obesity the GH response to hpGRF was strikingly reduced. These data demonstrate that hpGRF is a potent stimulus of GH release in normal prepubertal children and a physiological means of investigating GH function in diseases associated with growth impairment.

Clonidine accelerates growth in children with impaired growth hormone secretion.

4 children with isolated growth hormone deficiency (IGHD) and 4 with constitutional growth delay (CGD) were treated with clonidine, 0.1 mg/m2 daily, for 60 days. In 2 children with IGHD and all 4 with CGD, basal growth hormone (GH) and somatomedin-C levels were increased, pituitary GH response to challenges with a synthetic pancreatic GH releasing factor and clonidine was enhanced, and linear growth was stimulated.

Human pancreatic growth hormone (GH)-releasing hormone stimulates GH synthesis and release in infant rats. An in vivo study.

Administration of human pancreatic GH-releasing factor 1-40 (hpGRF-40) at doses of 1, 10, 20, 100, and 500 ng/100 g BW sc induced in 10-day-old rats a clear-cut rise in plasma GH 15-min post-injection, although the effect was not dose-related and peak GH levels were already present after the lowest GRF dose. In 25-day-old rats, hpGRF induced only a slight rise in plasma GH at the dose of 500 ng/100 g BW sc, whereas it was completely ineffective at the lower doses. In 5-day-old rats, hpGRF (20 ng/100 g BW sc twice daily), administered for 5 days, induced a marked rise in pituitary GH content and plasma GH levels determined 14 h after the last hpGRF injection. In these rats, at the end of treatment, a challenge hpGRF dose (20 ng/100 g BW) induced a rise in plasma GH significantly higher than in infant rats receiving only the challenge hpGRF dose. These data show that: 1) pituitary responsiveness to hpGRF is strikingly higher in infant than in post-weaning rats; 2) in infant rats, subacute administration of hpGRF stimulates GH synthesis and release.

Sexual maturation and adrenal function in girls with thalassemia.

Adrenal steroid production was evaluated in 12 thalassemic girls aged between 18 and 22 years and at stage P1 of sexual maturation according to Tanner. The values found in these patients were compared with those in 12 normal girls of the same age at stage P4-5 of sexual maturation. Pregnelone, dehydroepiandrosterone, dehydroepiandosterone sulfate, progesterone, 17-OH-P, androstenedione, testosterone, dihydrotestosterone and estradiol were found to be significantly reduced (p less than 0.001) in the thalassemic group, while cortisol levels showed a slight but not statistically significant reduction. Plasma ferritin levels were greatly increased and showed a highly significant (p less than 0.001) correlation coefficient when plotted against each hormone. The present results suggest that the impaired adrenal function plays an important role in determining the delayed sexual maturation almost always present in the thalassemic patients and that this disorder may be due to iron overload.

Growth-hormone releasing factor and clonidine in children with constitutional growth delay. Evidence for defective pituitary growth hormone reserve.

Six male prepubertal children with constitutional growth delay (CGD), and a subnormal growth hormone (GH) response to insulin hypoglycemia, and four normal prepubertal children were given in different occasions 1 microgram/Kg iv synthetic hpGRF-40 or a single oral dose of 0.15 mg/m2 clonidine (Clon), an effective growth hormone (GH) secretagogue. In the normal children brisk and clear-cut GH rises were detected in plasma after hpGRF-40 (peak GH levels at 15-30 min) or clonidine (peak GH levels 60-90 min). In CGD children hpGRF-40 induced a biphasic response, e.g. a slight increase in plasma GH at 15 min followed by a delayed and erratic GH rise occurring 45-120 min post-injection. Also the GH response to Clon was sluggish and delayed and peak plasma GH levels were attained only 90-180 min post-drug administration. These data indicate that the CGD children of our study have a defect in the pituitary GH reserve.

Adrenal and testicular function in boys affected by thalassemia.

The adrenal androgen secretion and testicular function were studied in 6 thalassemic boys aged between 16 and 20 years. Six normal boys of the same age and 6 at the same pubertal stage (P1 according to Tanner) were also studied as controls. Plasma testosterone levels were found significantly lower (p less than 0.001) in the thalassemic boys (0.8 +/- 0.1 ng/ml) than in healthy boys of the same age (3.4 +/- 1.01 ng/ml), but within the range of the healthy boys at the same pubertal stage (0.69 +/- 0.1 ng/ml). DHA-S, a marker of adrenal maturation, showed a similar pattern. The hCG test showed a significant (p less than 0.001) testosterone response in all 3 groups. The response of thalassemic boys (1.5 +/- 0.18 ng/ml) was similar to that of normal boys at stage P1 (1.8 +/- 0.31 ng/ml), but significantly lower (p less than 0.001) than the group of normal boys of the same age (12.5 +/- 3.2 ng/ml). The impaired adrenal and testicular activity is probably due to iron deposits in the endocrine glands.

Correlations between plasma levels of opioid peptides and adrenal androgens in prepuberty and puberty.

In 139 prepubertal children and in 38 pubertal adolescents plasma levels of ACTH, cortisol, beta-lipotropin (BLPH), beta-endorphin (BEP) and dehydroepiandrosterone sulphate (DHAS) were determined by specific radioimmunoassays directly (steroids) or after plasma purification (peptides). ACTH and cortisol concentrations remain stable during both prepuberty and puberty, while DHAS levels constantly increased from 5 to 16 years. Both BLPH and BEP increase from early infancy to late prepuberty when they reach adult values. During puberty both opioids remain constantly within the adult range. BLPH and BEP concentrations were significantly correlated to those of DHAS throughout prepuberty. These data suggest a possible role of BLPH and BEP in and/or other proopiocortin-related peptides in the development of adrenarche, while the lack of particular changes in these peptide levels during sexual maturation seems to exclude their role in gonadarche and pubertal development.

Proopiocortin-related peptide plasma levels throughout prepuberty and puberty.

The plasma patterns of ACTH, beta-lipotropin (beta LPH) and beta-endorphin (beta EP), in addition to those of cortisol and dehydroepiandrosterone sulfate (DHAS), were studied in 139 prepubertal children (subdivided into different age groups) and 38 adolescents (subdivided according to Tanner's pubertal stages) aged 10-16 yr. The adult control group was composed of 23 females and 12 males aged 17-40 yr. No sex differences were found in ACTH, beta LPH, beta EP, and cortisol plasma levels. ACTH plasma levels were slightly lower in the 1- to 3-yr-old groups than in males at 4-5 yr and females at 8-9 yr. No further significant differences were observed in any of the age or pubertal groups, the concentrations being constantly in the adult range. beta LPH and beta EP plasma levels were lowest at 1-3 yr in both males (beta LPH: 2.1 +/- 0.25, beta EP: 1.85 +/- 0.59 fmol/ml, mean +/- SE) and females (beta LPH: 2.8 +/- 0.31; beta EP: 2.41 +/- 0.41 fmol/ml); plasma levels of both hormones increased progressively in both sexes until Puberty 1 stage of sexual maturation, at which time levels were 7.3 +/- 0.78 and 8.69 +/- 1.0 fmol/ml in males and 7.1 +/- 0.34 and 6.76 +/- 0.13 fmol/ml in females; these levels are similar to adult values. A highly significant linear correlation was found between both beta LPH and beta EP concentrations and the age of the subjects; this was not true for ACTH plasma levels. Cortisol plasma levels were similar in all groups. DHAS plasma levels increased progressively from 1-3 yr to the end of sexual maturation when adult values were reached. During prepuberty, DHAS levels were significantly correlated with both beta LPH and beta EP, but not ACTH. These data indicate that plasma beta LPH and beta EP concentrations, in contrast to ACTH levels, increase progressively throughout prepuberty and suggest that the processing of the parent proopiocortin molecule or secretion of the processed peptides from the anterior pituitary (or other sources) may change from early infancy to adulthood. Furthermore, the correlation between both beta LPH and beta EP with DHAS plasma levels in prepuberty suggests a role of proopiocortin-related peptides in adrenarche.

Puerperal breast feeding does not stimulate circulating opioids in humans.

ACTH, beta lipotropin (beta LPH), beta endorphin (beta EP), Prolactin (PRL) and Cortisol were measured in the first five days of puerperium at 9:00, before and 30 minutes after suckling, in 7 healthy lactating women. With the exception of PRL plasma levels which decline, although remaining at high concentrations during the observation period, all the other parameters showed a sudden fall from the high levels found at delivery, reaching stable normal levels (beta LPH, beta EP, Cortisol) or concentrations which were 50% lower than normal (ACTH), from the second day of puerperium. Suckling confirms its capacity to release plasma PRL, while all the other indices remain unmodified. Despite the experimental evidence that serotoninergic neurons are involved both in the PRL response to suckling and the circadian rhythmicity and stress response of proopiocortin-related peptides, the present results suggest that breast feeding is not a stressful situation, as no typical proopiocortin-related peptide response is evident, and that the activation of PRL release is related to stimulation of serotoninergic neurons which differ from those involved in the control of proopiocortin-related peptide secretion.

[Therapy of bronchospasmic crisis of childhood with aminophylline]. / Terapia delle crisi broncospastiche dell'infanzia con aminofillina.

We tested a new product containing aminophylline with 1,56% alcohol as therapy of bronchospasm in childhood to evaluate therapeutic activity, tolerance and adverse reactions. Authors confirm the usefulness of this product in childhood but dosage must be individualized with monitoring of theophylline blood levels.