The impact of cardiopulmonary bypass on selenium status, thyroid function, and oxidative defense in children

Selenium has important functions for oxidative defense and thyroid hormone metabolism. Selenium-dependent enzymes include 5'-iodothyronine deiodinase and glutathione peroxidase (GPX). The objective of this study was to investigate the relationship between plasma selenium, GPX activity, and thyroid hormone status in pediatric cardiac surgical patients. Plasma concentrations of selenium, free triiodothyronine (fT3), free thyroxin (fT4), and c-reactive protein as well as plasma activity of GPX were prospectively evaluated at anesthetic induction and 48 hours postoperatively in 59 children requiring cardiopulmonary bypass (CPB). GPX was measured at additional time points at 6, 12, and 24 hours postoperatively. There was a significant reduction in the plasma selenium concentration after cardiopulmonary bypass with obtained median measurements of 0.61 micromol/L (induction) and 0.51 micromol/L (48 hours postoperatively). The fT3/fT4 ratio decreased significantly from 0.28 at anesthetic induction to 0.22 at 48 hours postoperatively. There were no significant changes of GPX activity. 48 hours fT3 concentration, fT3/fT4 ratio, and selenium concentration were significantly negatively correlated with the time spent in intensive care. The concentration of plasma selenium in children undergoing cardiopulmonary bypass significantly decreases, resulting in diminished deiodinase activity, and a subsequent reduction in the conversion of T4 to T3.

Idiopathic multifocal intracardiac and pulmonary thrombosis: successful treatment with rTPA

A 21-month-old boy with respiratory symptoms for one month secondary to idiopathic multichamber intracardiac and pulmonary thrombosis is presented who was successfully treated with recombinant tissue plasminogen activator (rTPA). The etiology and risk factors of pediatric intracardiac thrombosis are discussed and the literature and all reported cases are reviewed. It is important to consider cardiopulmonary thrombosis as a differential diagnosis of respiratory distress in childhood.

The Ross procedure in children under ten years of age

BACKGROUND AND AIMS OF THE STUDY

The potential advantages of the Ross procedure in children under 10 years of age have yet to be validated. Concerns remain regarding progressive dilatation of the pulmonary autograft and potential homograft stenosis. We present our experience in this age population.

METHODS

A retrospective analysis of aortic root replacement using the Ross procedure in 11 young children (nine males, two females; median age 84 months; range 3 months to 10 years) between January 1996 and January 1999 was performed jointly in two pediatric surgical centers.

RESULTS

There were no operative deaths. Mean hospital stay was 12 +/- 4 days, and mean follow up 14.5 +/- 8 months. The event-free survival (death, reoperation, endocarditis, arrhythmia) was 100%. Currently, nine children are in NYHA functional class I, and two in class II. The autograft and homograft were evaluated by serial echocardiography. There was no sign of progressive dilatation of the autograft. Aortic regurgitation was trivial in four children and mild in seven. No growth of the autograft was noted; this was consistent with minimal somatic growth. Homograft peak gradients remained low during the follow up.

CONCLUSIONS

Although the pulmonary autograft procedure is more complex than other types of aortic valve replacement, it can be safely applied in children. Early follow up indicates satisfactory performance of the autograft. If dilatation will not occur, pulmonary root autograft may be an attractive substitute for diseased aortic valves in children.

[Stents in the treatment of stenosis of the entero-urethral junction in continent diversion: case reports]

Strictures of entero-urethral anastomosis in orthotopic neobladder and of the catheterizable conduit in continent diversion after cystectomy are seldom encountered; they are usually treated with dilation, TUR or cold incision. 3 cases that came to our observation are presented. The first was treated with TUR after neo-bladder neck stricture in orthotopic neobladder; total incontinence occurred after this procedure. The patient at present is waiting for AS800 artificial sphincter implant. The second patient had similar features. After repeat TUR a prostacoil removable stent was placed through the stricture and removed after 5 months. At 12 months from removal the patient is continent and doesn't present clinical evidence of restriction. The third patient underwent cystectomy with Indiana continent pouch. After 4 months increasing problems in self catheterization occurred due to stricture of the catheterization conduit (appendix). He was treated twice with cold incision with early recurrence of the stricture. A permanent Memotherm stent (indicated for urethral strictures) was placed inside the appendix. After one month self catheterization was started again. At a 2 months follow up there is no evidence of stricture. In our experience, even if anecdotal, we have verified that treatment of this kind of strictures with TUR can cause incontinence or expose to further recurrences. 2 of the cases presented were treated with different kind of stents; the outcome is good even if the follow up is still short. We believe that this kind of treatment can be considered in selected cases.

[Echographic and sonographic study of ovaries in girls with precocious puberty]

The aim of this study is the biometrical and morphological evaluation of the ovaries by sonography and the study of the haemodynamics of the ovarian artery flow by doppler ultrasound in 14 girls with precocious puberty and in 33 control subjects. All people ranged in age from 5 to 7 years. The gonadian mean volume and the mean pulsatility index have been evaluated. A significant difference in the ovarian volume has been found between patients and controls. No index between the two groups. We conclude that the doppler ultrasound needs a larger number of cases to evaluate its validity in girls with precocious puberty.

Fetal behavioural states and hypertensive pregnancy

Delay in fetal maturation in diabetic and accelerated fetal maturation in hypertensive pregnancies have been reported in the past. The spontaneous activity of fetal nervous system during pregnancy was followed longitudinally in a group of 29 normal pregnancies from 28 x th to 40 x th week of gestation by means of fetal behavioural states determination. 1 F state (quiet sleep) progressively increases from median values of 5.0% to values of 22.5-25% at term of pregnancy. This state represents the positive activity of inhibitory centers has been related to a positive evolutionary process of brain maturation according to preceding experiences conducted on experimental models and preterm babies followed with EEG and direct observation in the early neonatal period. The method of behavioural states determination has been applied to a group of 33 gestational diabetes (GDM) pregnant women followed longitudinally, and a clear reduction of development of 1 F state has been evidentiated, with significant differences (p less than 0.001) at 35-36 weeks of gestation versus the control group. The normal values are reached in concomitance with L/S value of maturity. In 30 pregnant women affected by gestational hypertension (GH) different result are obtained: 1 F state seems to develop earlier, and is increased (p less than 0.001) around 30-32 weeks versus the control group if a fetal growth reduction is present. The value of 1 F behavioural state in the evaluation of fetal condition of pathological pregnancies is discussed.

Calcitonin secretion rate in elderly normal subjects

The aim of the study was to investigate the metabolic clearance rate (MCR) and the secretion rate (SR) of calcitonin (CT) in elderly men and women (mean age +/- SE: 75 +/- 3 and 78 +/- 3 yr, respectively). The basal levels of CT were higher in men than in women (9.6 +/- 3.2 vs 6.0 +/- 1.5 pg/ml; p less than 0.05). The MCR was not significantly different between sexes (905 +/- 54.2 vs 810 +/- 165.1 l/day). In contrast, CT SR was significantly higher in male subjects compared to women (8.7 +/- 3.1 vs 4.8 +/- 1.5 micrograms/day; p less than 0.05). These findings suggest that only a few units of CT are secreted daily by elderly subjects and that the lower basal values of the hormone in women are probably the result of a lower production rate.

Osteocalcin levels in diabetic subjects

Because a series of reports suggests the existence of altered bone and mineral metabolism in diabetes mellitus, we studied 106 diabetic subjects (42 insulin-dependent (IDD) and 64 noninsulin dependent (NIDD] to determine whether a difference in bone turnover (evaluated by serum osteocalcin (OC] could be found in comparison with normal controls. OC levels in diabetic subjects were lower than the age- and sex-specific predicted values. The reduction was especially evident in male and female NIDD (Z-score: - 1.12 +/- 0.92, t = 8.4, P less than 0.001 and -0.84 +/- 0.86, t = 4.0, P less than 0.01, respectively) and male IDD (Z-score: - 0.90 +/- 0.86, t = 4.5, P less than 0.01). The mean Z-score for female IDD, albeit negative (-0.31 +/- 0.79; t = 1.6; 0.2 greater than P greater than 0.1), was not significantly different from normal. Total serum calcium (Ca) and calcitonin (CT) showed an opposite pattern, being higher in all the diabetic subgroups (with the exception of Ca in female IDD), whereas parathyroid hormone (PTH) was lower than expected in each diabetic subset. By multiple regression analysis, the reduction of OC was related to PTH and CT levels and to the type of treatment. Subjects controlled with diet showed differences of greater magnitude from the expected normal values than those treated with oral hypoglycemic agents or insulin (Z-score: -1.28 +/- 1.05 vs. -0.85 +/- 0.90 and -0.63 +/- 0.97, respectively; P = 0.05). However, the variance explained by these three factors was small, suggesting that other variables (possibly 1 alpha,25(OH)2D) exerted important influences on OC levels.

Short-term effects on bone and mineral metabolism of 4-amino-1-hydroxybutylidene-1,1-diphosphonate (ABDP) in Paget's disease of bone

To study the short-term effects on mineral and bone metabolism of a recently introduced amino-diphosphonate (4-amino-1-hydroxybutylidene-1,1-diphosphonate or ABDP), 10 patients suffering from active Paget's disease were examined. Each subject received intravenously 5 mg/day of ABDP for 4 days and the effects of treatment were monitored for 12 days. ABDP administration was followed by an early and significant decrease of the urinary hydroxyproline and calcium excretion, of the theoretical renal threshold for phosphate of the serum calcium. Serum phosphate also decreased, while its urinary excretion increased. Intact parathyroid hormone levels at the end of treatment were four times higher than basal levels. Total and bone alkaline phosphatase tended to decrease only slightly at the end of the observation, whereas serum osteocalcin, tended to increase. These findings indicate that the earlier effect of ABDP is a profound inhibition of bone resorption, which brings about a compensatory parathyroid hormone response. The decrease of urinary hydroxyproline follows an exponential curve, with a calculated half-life of 2.2 days, suggesting an approximate equivalency of 5 mg/day ABDP to slightly more than 30 mg/day 3-amino-1-hydroxypropylidene-1,1-diphosphonate. Bone formation seems scarcely influenced in the short-term, but osteoblastic indices show a contrasting behaviour, which may reflect a different biological origin and/or significance.

Spontaneous release of interleukin-1 (IL-1) from medullary mononuclear cells of pagetic subjects

The Authors examined interleukin 1 (IL-1) secretion from the peripheral and medullary mononuclear cells, obtained with sequential separation on Ficoll-Hypaque and 45% Percoll gradient, in 6 pagetic subjects and 6 normal controls. Both peripheral and medullary cells from pagetic subjects showed a significantly greater IL-1 production after stimulation with lipopolysaccharides (LPS); moreover, we observed a spontaneous IL-1 release from medullary cells in pagetic subjects but not in normal controls. These findings suggest a possible role of IL-1 in the elevated bone turnover of Paget's disease of bone.

[Effects of alpha-calcidiol (1 alpha-hydroxy-cholecalciferol) on the serum levels of osteocalcin in involutional osteoporosis]

We have examined the effects of 1 alpha-hydroxycolecalciferol (1 alpha) (1.5 micrograms for 5 days) on serum osteocalcin (OC) and other parameters of bone and mineral metabolism in 20 osteoporotic women and 11 age-matched normal women. After 1 alpha administration, a statistically significant (p less than 0.01) increase of serum OC, calcium and phosphate and urinary calcium and hydroxyproline was observed. In contrast, alkaline phosphatase was unchanged. There was no significant difference between normal and osteoporotic women in the changes of any of the parameters we monitored. In particular, OC increased in a comparable way in both groups. Thus, by means of an index that reflects the global activity of the skeleton, we could not find any apparent defect of osteoblastic responsiveness to the drug in osteoporotic subjects.

Meal-stimulated gastrin release and calcitonin secretion

In order to study the effects of a physiologic meal on calcitonin (CT) secretion we studied 6 normal male volunteers (aged 28-34 yr). Each subject was given, on two separate days, either a mixed meal or 200 ml of distilled water, in random order. Gastrin (G) was effectively stimulated by the meal (F = 8.82; p less than 0.001) and reached a peak (with an average 100% increase) 30 min after the end of the meal, slowly decreasing thereafter; no increase was seen after water ingestion. On the other hand, CT levels remained stable throughout the observation period on both occasions. Ionized and total calcium did not show significant variations either after the meal or after water ingestion. These findings suggest that G alone, at the concentrations usually reached after a physiologic meal, is unable to stimulate CT secretion, at least in the absence of calcium increases.

[Sequential calcitriol-calcitonin in the therapy of osteoporosis]

Different therapeutic regimens have been proposed by Authors in the treatment of involutional (and particularly postmenopausal) osteoporosis. Following the up to date concepts on bone remodelling, an ADFR (Activate, Depress, Free, Repeat) trial was performed in 20 females affected by involutional osteoporosis. They were treated with Calcitriol 2 mcg/d for 7 days, followed by a 21 days period of 100 U/d Salmon Calcitonin + 1 g/d Calcitonin, followed by a 2-month period of Calcium alone. The cycles were repeated for 1 year and the results of densitometric examinations (radial mineral content evaluated by single photon absorptiometer, and vertebral mineral content evaluated by dual photon absorptiometer) and of biochemical markers (Ca++, P, osteocalcin, alkaline phosphatase, hydroxyproline) controlled every 3 months, were compared with those obtained in a group of patients treated only with Salmon Calcitonin and in a group treated with Calcium for 1 year. After two therapeutical cycles radial bone mineral density significantly increased; vertebral bone density also increased but not significantly. The effects were more evident in comparison to calcitonin alone treatment. A significant reduction in serum osteocalcin was documented. At the end of the therapy no further improvement was registered. This suggests that some variations and adaptation of therapeutic strategy are needed to achieve a more important and substantial improvement of bone conditions.

Tryptophan availability and fetal behavioral states

Behavioral state instability in growth-retarded fetuses might be related to a decrease in serotonine production. Tryptophan maternal and cord blood values after elective cesarean section have been investigated by means of high performance liquid chromatography in 20 growth-retarded fetuses due to pregnancy-induced hypertension (PIH) and 20 normal pregnancies as control group. The feto-maternal ratio of tryptophan is significantly higher in normal fetuses than in PIH growth-retarded fetuses (p less than 0.001). Behavioral states have been determined 1 week and just before cesarean section. Values of 1F, 2F, 3F and 4F differ in the 2 groups (p less than 0.001). A higher percentage of non-coincidences (p less than 0.001) and state interruptions (p less than 0.001) is found in PIH fetuses. A significant correlation is demonstrated between the increase of non-coincidences and decrease in the feto-maternal Trp ratio (p less than 0.001).

Calcitonin levels in normal women of various ages evaluated with a new sensitive radioimmunoassay

In order to establish the normal range of serum Calcitonin (CT), evaluated with a new, sensitive radioimmunoassay in normal women of various ages, 67 female subjects were examined. CT levels were detectable in all the subjects, with a reference interval (bounded by the 2.5 and 97.5 percentiles) of 3.6-16.9 pg/ml; a very slight decrease with age was observed (correlation coefficient = -0.24; P = 0.05; regression equation: CT = 9.55--0.042 x age). This assay seems sensitive enough to permit the measurement of CT in physiological conditions.

[Changes in bone mass with age. Transversal study on a female population using photon densitometry]

In order to evaluate the age-related changes of the bone mineral content (BMC), 281 clinically healthy women (20-80 year old) underwent single photon abosorptiometry (SPA) on the distal third of the radius (where there is a prevalence of cortical bone); 161 subjects of this group were examined also by dual photon absorptiometry (DPA) of the lumbar tract of the spine (L2-L4) (trabecular bone). The relationship of trabecular BMC with age is described by a cubic polynomial regression (r = 0.46; p less than 0.0001) that shows an increase in BMC until 31 years of age followed by a decrease with a minimum at the age of 78; afterwards trabecular BMC adds an apparent increase. No increase in the rate of trabecular BMC loss was seen after the menopause. A positive correlation was found between body weight and vertebral BMC. The behaviour of cortical BMC with age is described by a quadratic regression (r = 0.42; p less than 0.0001) that shows an increase until 32 years of age followed by a decrease. Cortical BMC shows a significant decrease after menopause. No correlation was found between body weight and cortical BMC. These findings underline the different behaviour of trabecular and cortical bone tissue with age; in addition, the relation between trabecular (but not cortical) BMC and body weight argues for an important role of biomechanical factors in the local modulation of bone mass.