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Biomedical subjects

A G Vagenakis

Publications and source records attributed to A G Vagenakis.

At least 19 recordsLinked to original sources
PubMed1998

Insulin resistance, hyperinsulinemia, and hypertriglyceridemia in patients with coronary artery disease independent of obesity.

Insulin resistance and hyperinsulinemia both in normal persons and those with non-insulin dependent diabetes mellitus (NIDDM) (type 2 diabetes) appears to be related to obesity. It seems also that insulin plays a role in modulating the obesity-related factors (eg, hyperinsulinemia, hyperglycemia, hypertension, hypertriglyceridemia, hypercholesterolemia, low concentrations of high-density lipoprotein cholesterol) and takes its place among the many risk factors for coronary artery disease (CAD) associated with obesity. Insulin resistance and hyperinsulinemia could play the same role in pathogenesis of CAD independently of obesity. The authors determined blood glucose and immunoreactive insulin and plasma triglyceride concentrations in the fasting state at 60 and 120 minutes after a glucose load of 75 g in 68 patients (54 men, 14 women) with angiographic evidence of CAD and in 65 healthy volunteers matched to the patients for age, gender, and body mass index (43 men and 22 women). Patients with CAD and the healthy volunteers were categorized as obese (body mass index > or = 26 kg/m2) and nonobese (body mass index < 26 kg/m2). Four groups of subjects were analyzed: Group A included 40 healthy (28 men and 12 women) nonobese volunteers; group B, 25 healthy (15 men and 10 women) obese volunteers; group C, 39 (30 men and 9 women) nonobese patients with CAD; and group D, 29 (24 men and 5 women) obese patients with CAD. Fasting and postchallenged 60- and 120-minute glucose values were similar in groups A and C. However, significantly higher insulin values (mU/L) were observed in group C than in group A during fasting (12.2+/-6.2 vs 91+/-3, p<0.05), and postchallenged at 60 minutes (103.1+/-53.2 vs 71.9+/-64.3, p<0.01) and 120 minutes (57.9+/-41.2 vs 44.9 +/-41.3, p<0.01). Fasting glucose and insulin values were similar in groups B and D. However, significantly higher glucose (mg/dL) and insulin values were observed in group D than in group B postchallenged at 60 and 120 minutes: glucose at 60 minutes (188.7 +/-45.1 vs 154.2+/-37.5, p<0.05); insulin at 60 minutes (127.5+/-98.5 vs 112.1+/-81.1, p<0.05); glucose at 120 minutes (124.2+/-46.1 vs 99.5+/-28.9, p<0.05); insulin at 120 minutes (86.1+/-57.6 vs 62.8+/-27.9, p<0.05). The glucose and insulin values during 60- and 120-minute fasting as well as postchallenged were similar in groups B and C. Significantly higher plasma triglyceride concentrations were observed in group C than in group A (149.0+/-64.1 vs 114.6+/-46.6, p<0.01) and in group D compared with group B (229.4+/-104.7 vs 144.9+/-65.1, p<0.001). Plasma triglyceride concentrations were similar in groups B and C. The authors conclude that patients with documented CAD are insulin resistant independently of obesity.

Blood Glucose↗
PubMed1996

Thyroid function and immune profile in rheumatoid arthritis. A controlled study.

The aim of our study was to determine the prevalence of thyroid dysfunction and autoimmune abnormalities in rheumatoid arthritis (RA) and to further investigate the possible association between D-penicillamine and autoimmune thyroiditis. For this purpose, one hundred and one unselected consecutive patients with RA and 70 age and sex matched controls were studied prospectively. Evaluation included a complete history and physical examination with special attention to symptoms suggestive of thyroid pathology, routine laboratory and serologic immune profile, plus determination of serum levels of thyroxine (T4), triiodothyronine (T3), thyroid stimulating hormone (TSH), antibodies to thyroid peroxidase (AbTPO) and TSH receptor antibodies (TRAB). Serum thyroxine binding globulin (TBG) was measured in all subjects with high thyroid hormone levels, whereas free T3 and T4 concentrations were determined in all individuals with abnormal T3, T4, TSH or TBG. Six patients with hyperhyroidism, 3 with hypothyroidism and 1 with the euthyroid hyperthyroxinemia (EH) syndrome were found, whereas four of the controls had hyperthyroidism. Thirteen patients and 6 controls had high AbTPO levels whereas no one had high TRAB. No association was detected between thyroid abnormalities and any serologic RA finding. Furthermore, no correlation between thyroid dysfunction and elevated AbTPO's was found. A relatively high prevalence of thyroid dysfunction (9,9%) and subclinical autoimmune thyroiditis (12,9%), the latter indicated by elevated AbTPO's, was found in our RA patients. These figures were higher than those in the control group (5,7% and 8,6% respectively), but the difference did not reach statistical significance. Of further interest may be our finding that, despite anecdotal reports blaming D-penicillamine for cases of autoimmune thyroiditis, the incidence of the latter was similar among recipients and nonrecipients of the drug. Similarly, TRAB were not detected in any patient treated with D-penicillamine.

Adult↗
PubMed1996

Repolarization abnormalities with prolonged hyperventilation in apparently healthy subjects: incidence, mechanisms and affecting factors.

Brief hyperventilation is occasionally accompanied by repolarization abnormalities in subjects without apparent heart disease. However, the effect of prolonged hyperventilation on repolarization abnormalities is not clearly defined. We analysed the repolarization abnormalities induced by prolonged hyperventilation, correlated with hyperventilation induced haemodynamic changes and exercise test results and assessed the effect on them of age, gender, smoking and hypertension. Prolonged hyperventilation (overbreathing at least 30 respirations/min for 5 min and 10 min recovery) was performed in 474 healthy volunteers (269 men, 205 women) 42.6 +/- 13.5 years old. The electrocardiogram was analysed for transient ST depression or T-wave inversion. Repolarization abnormalities were observed in 72 subjects, 47 men (17.5%) and 25 women (12.2%). Age, gender, smoking and hypertension did not influence the overall incidence of repolarization abnormalities. ST depression was more frequently observed in women (4.4 vs 0.7%, P < 0.01), while T wave inversion from negative to positive was more frequent in men (8.9 vs 2.4%, P < 0.006). All subjects with ST depression were non-smokers (4.1% of the non-smokers, P < 0.003 compared to smokers). Repolarization abnormalities occurred usually (80.5%), but not exclusively, within the first hyperventilation minute. Subjects with repolarization abnormalities developed higher heart rate change with hyperventilation than those without repolarization abnormalities (29.2 +/- 13.1 vs 24.2 +/- 12.7, P < 0.002). A positive exercise test was observed in 45.4% of subjects with hyperventilation induced ST depression but only in 13.1% of subjects with T-wave changes, P < 0.02. Repolarization abnormalities are not uncommon during prolonged hyperventilation. Hear rate change affects the occurrence of repolarization abnormalities, while gender and smoking influence the type of repolarization abnormalities. ST depression but not T-wave inversion during hyperventilation is associated with a positive exercise test. Increased understanding about hyperventilation-induced repolarization abnormalities could affect use of the method in the clinic, either as a provocation test or as a complement to the interpretation of the exercise test.

Adult↗
PubMed1996

Prolactin and growth hormone in perinatal asphyxia.

To assess the pituitary response to perinatal asphyxia, the prolactin (PRL) and growth hormone (hGH) serum concentrations were measured in 55 asphyctic (15 preterm and 40 full-term) and 35 control (15 preterm and 20 full-term) newborns at 2-4, 24, 48 and 98 h of life. At 2-4 h the median PRL in the preterm asphyctic neonates was 5.2 U/l, whereas in the preterm control newborns it was 3.2. In the full-term newborns with and without hypoxic-ischaemic encephalopathy (HIE) it was 5.8 and 3.4, respectively. In the full-term neonates with HIE the PRL remained significantly higher than in the controls up to the fourth day. At 2-4 h the median hGH in the preterm asphyctic and control newborns was 106.2 and 54.8 mU/l, respectively. In full-term newborns it was 85.0 and 40.8, respectively. The lowest hGH concentrations were found in the severe HIE. The increased PRL and hGH in asphyxia may result from a stress-related hormone release, whereas the very low hGH concentrations in severe HIE may result from a damage at the hypothalamic-hypophyseal axis.

Asphyxia Neonatorum↗
PubMed1995

Hemodynamic response to hyperventilation test in healthy volunteers.

Hyperventilation is well known to affect the electrocardiogram (ECG) in subjects without heart disease and produce spasm in patients with variant angina. The autonomic nervous system is thought to play a significant role in these effects. However, the normal hemodynamic response to hyperventilation is not well defined. We subjected 369 healthy volunteers (200 men, 169 women) to prolonged hyperventilation (30 respirations for 5 min and 10 min recovery) under continuous ECG monitoring and to exercise testing. Heart rate (HR), systolic and diastolic blood pressures (SBP, DBP) and rate-pressure product were recorded. Hyperventilation resulted in an immediate (within the first min), significant increase in HR by 27.4%, a further small increase at min 2 of hyperventilation, and a subsequent small decrease in HR at mins 3-5. An immediate drop of HR by 20.1% was observed with discontinuation of hyperventilation. Apart from a slightly higher HR increase in men, a similar pattern of HR changes was found in both genders. On multivariate analysis, younger age, absence of smoking, and male gender were associated with a higher HR increase with hyperventilation (p < 0.0001, p < 0.0001, and p < 0.001, respectively). SBP and DBP increased with hyperventilation, with their highest value at min 5 of hyperventilation and a subsequent drop to baseline levels. Age and gender did not affect the degree and pattern of BP changes. Absence of smoking and the presence of hypertension were associated with a higher SBP with hyperventilation (p < 0.003 and p < 0.007). The rate-pressure product increased by 43.6% with hyperventilation, a change that was only 19.1% of the respective rate-pressure product observed with exercise. Hyperventilation results in significant HR and BP increases, changes that are influenced by age, gender, smoking, and hypertension. Our study could serve as a standard for comparison of the hyperventilation effects in different disease states.

Adult↗
PubMed1994

Increased levels and positive correlation between erythropoietin and hemoglobin concentrations in newborn children of mothers who are smokers.

The mean erythropoietin concentration in the cord blood of neonates whose mothers were smokers was greater than in neonates whose mothers were not smokers. There was a significant positive correlation between erythropoietin and hemoglobin concentrations. The findings suggest that approximately one of five fetuses who are exposed to tobacco smoke are in a state of chronic hypoxia.

Arginine Vasopressin↗
PubMed1994

Prolactin, growth hormone and insulin-like growth factor-I in newborn children of smoking mothers.

OBJECTIVE: Since maternal smoking causes fetal circulatory abnormalities, as well as disturbances of the maternal endocrine equilibrium, we measured the PRL, hGH and insulin-like growth factor-I (IGF-I) concentrations in the cord and venous blood of neonates of smoking mothers to determine whether or not the tobacco smoke affects the endocrine status of the neonate. DESIGN: The above hormones were measured in the cord blood of the newborns of both smoking and non-smoking mothers. Also, PRL and hGH were determined at 24 and 72 hours after birth in newborns of both groups. PATIENTS: Fifty-three newborns of smoking and 47 newborns of non-smoking mothers were investigated. Seventeen of the newborns of the smoking and 21 of the non-smoking mothers were preterm. The remainder were full-term. MEASUREMENTS: PRL was measured with a solid-phase immunoradiometric assay, hGH with a solid-phase two-site immunoradiometric assay and IGF-I with a solid-phase radioimmunoassay after extraction with acid-ethanol. RESULTS: The median value of PRL in the 17 preterm newborns of smoking mothers was 4941 mU/I (range 1322-7230), whereas in the 21 preterm newborns of non-smoking mothers it was 2013 mU/I (range 243-4740) (P = 0.0002). The median hGH value in the above subjects was 102.0 mU/I (range 35.2-208.4) and 59.8 mU/I (range 11.6-134.2), respectively (P = 0.0039). The median IGF-I was 580.7 U/I (range 253.2-4851.1) and 530.6 U/I (range 239.6-3591.5), respectively (P = 0.429). In the 36 full-term newborns of smoking mothers the median PRL value was 5171 mU/I (range 2074-7530), whereas in the 26 full-term newborns of non-smoking mothers it was 5081 (range 244-6540) (P = 0.048). The median hGH was 69.6 mU/I (range 42.3-280.0) and 32.2 mU/I (range 6.2-200.0), respectively (P = 0.0031). Also, the median IGF-I value was 926.3 U/I (range 348.5-5344.7) and 462.1 U/I (range 250.2-1578.7), respectively (P = 0.0024). On the 3rd day the PRL in the preterm neonates of both smoking and non-smoking mothers showed the same 16.5% drop, and thus the difference between the groups was maintained. A similar reduction in the hormone levels was observed in the full term neonates. CONCLUSIONS: The findings indicate that the maternal tobacco-smoking causes disturbances of the endocrine status of the fetus, as shown by the increased levels of PRL, hGH and IGF-I, which are more pronounced between 30 and 37 weeks of gestation than at term.

Female↗
PubMed1994

Growth hormone, insulin-like growth factor-I and prolactin in small for gestational age neonates.

Growth hormone (hGH), insulin-like growth factor-I (IGF-I) and prolactin (PRL) were measured in the cord and venous blood of small for gestational age (SGA) neonates in order to evaluate their endocrine status during the first 3 days of life. Although there were SGA newborns with both high and normal levels of hGH, the mean (+/- SD) concentration of hGH in the cord blood of the SGA neonates was 72.1 +/- 50.6 ng/ml, whereas in the appropriate for gestational age (AGA) newborns it was 37.0 +/- 23.5 (p = 0.001). The IGF-I in the cord blood of the SGA and the AGA newborns was 194.2 +/- 174.8 ng/ml and 77.3 +/- 50.2, respectively (p = 0.013). The PRL in the SGA and AGA newborns was 184.8 +/- 62.4 ng/ml and 126.8 +/- 60.5, respectively (p = 0.0005). On the 3rd day the hGH in the SGA babies was 50.7 +/- 41.2, whereas in the AGA it was 24.3 +/- 12.3 (p = 0.034). On the same day the IGF-I was 133.9 +/- 120.9 and 44.8 +/- 31.6, respectively (p > 0.05). Similarly, the PRL was 157.1 +/- 52.3 and 90.9 +/- 52.5, respectively (p = 0.0008). All neonates with high hGH concentrations had low IGF-I levels, whereas of those with normal hGH half had high and half normal IGF-I levels. There was no difference in the hormone levels between symmetric and asymmetric intrauterine growth-retarded infants. The findings suggest that the SGA neonates are heterogeneous comprising three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

Hyperinsulinaemia in syndrome X: a marker of the syndrome?

BACKGROUND: Stimulated hyperinsulinaemia is observed in some patients with syndrome X, defined as angina, positive stress test and normal coronary arteriography, and may be involved in the pathogenesis of the syndrome. An increased sympathetic response to exercise may also be pathogenetically involved. However, the diagnostic value of hyperinsulinaemia as a marker of this syndrome has not been defined. METHODS: We determined blood glucose and immunoreactive insulin during fasting, at 60 and 120 min after a glucose load of 75g in 21 patients (eight men, 13 women, 53.9 +/- 7.1 years old) with syndrome X and in 21 healthy volunteers matched to the patients for age, sex and body mass index (eight men, 13 women, 51.6 +/- 9.3 years old). Insulin values were related to the rate-pressure product increase at first exercise stage. RESULTS: The glucose values as well as the insulin values during fasting were similar in syndrome X patients and in controls. However, significantly higher insulin values (mU/l) were observed at 60 (P < 0.01) and 120 min (P < 0.005) in syndrome X patients (median 75.5 and 52, range 43-290 and 6.1-212, respectively) than in controls (median 47.5 and 24.5, range 8-195.6 and 5.2-164, respectively). A considerable overlap of insulin values, however, was observed between the two groups, with abnormal values even during fasting. For a specificity of 95%, an abnormal insulin value had a sensitivity of between 19 and 24% and a diagnostic accuracy of 57-60%. A significant positive correlation was found between insulin levels after the glucose load and the rate-pressure product increment with exercise (60 min, r = 0.60; 120 min, r = 0.65). CONCLUSION: Hyperinsulinaemia may be pathogenetically involved in syndrome X patients, in close relation to the higher sympathetic drive that characterizes this syndrome. However, the wide range of insulin values, frequently overlapping with normal values, limits the usefulness of this abnormality as a marker of the syndrome.

Blood Glucose↗
PubMed1993

Three cases of varicella thrombophlebitis as a complication of varicella zoster virus infection.

Three cases of deep venous thrombosis following varicella infection are described which were successfully treated with bed rest and anticoagulants. Two of these patients had severe pulmonary manifestations of varicella and the third was complicated by pulmonary embolism. Deep vein thrombosis is an uncommon systemic manifestation of varicella, possibly associated with vascular endothelium wall damage caused by varicella zoster virus infection.

Adolescent↗
PubMed1992

Varicella pneumonia in adults. A review of pulmonary manifestations, risk factors and treatment.

Pneumonia is a rare but serious and occasionally fatal complication of varicella. Two cases of varicella pneumonia were successfully treated with acyclovir in our department. We reviewed the pulmonary manifestations of varicella, the risk factors and the effect of acyclovir on varicella pneumonia on immunocompetent adults. Early, aggressive therapy with acyclovir seems to abort the catastrophic consequences of varicella pneumonia, while oral acyclovir chemoprophylaxis is probably beneficial in high-risk populations with chickenpox.

Acyclovir↗
PubMed1992

Development of thyrotropin circadian rhythm in infancy.

Normal children and adults show a similar pattern of diurnal variation of TSH secretion with lower values at 1100 h and higher around 2300 h. The purpose of this study was to investigate the age of appearance of TSH circadian rhythm. In 57 fullterm infants 0-6 months old and in 37 premature infants 1-4 weeks old TSH was measured at 1030, 1100, 1130 h and 2230, 2300, and 2330 h. No diurnal rhythm was detected in both premature and fullterm infants less than 4 weeks of life. After the first month of life a significant difference between AM and PM values was observed in fullterm infants. In infants 1-2 months old mean +/- SEM AM and PM values were 2.8 +/- 0.2 and 3.5 +/- 0.4 mU/L, respectively (P less than 0.025), in infants 3-4 months old 3.0 +/- 0.6 and 4.1 +/- 0.8 (P less than 0.01) and in infants 5-6 months old 1.8 +/- 0.2 and 2.6 +/- 0.3 (P less than 0.0005). These data clearly indicate that the development of TSH circadian rhythm starts after the first month of life.

Circadian Rhythm↗
PubMed1992

Abnormal overnight dexamethasone suppression test in subjects receiving rifampicin therapy.

We have studied the effects of rifampicin on the overnight 1-mg dexamethasone suppression test usually employed to exclude suspected Cushing's syndrome. Previous observations indicate that in humans, rifampicin profoundly attenuates the biological effects of hydrocortisol and prednisolone, probably by increasing the metabolism of these drugs in the liver. The study was carried out in 16 normal volunteers. All subjects had a normal overnight 1-mg dexamethasone suppression test (468 +/- 86 vs. 32 +/- 21 nmol/L; mean +/- SD). In 8 subjects treated with rifampicin (600 mg) for 10 days, the inhibitory effect of dexamethasone on serum cortisol was completely prevented (575 +/- 114 vs. 434 +/- 82). In the remaining 8 rifampicin-treated subjects, the inhibitory effect of 1, 2, or 3 mg dexamethasone on serum cortisol was not observed. When 4 mg dexamethasone were administered, the serum cortisol level was 193 nmol/L, above the expected normal suppression value. The plasma dexamethasone concentration was very low after rifampicin treatment (range, 1.2-4.8 nmol/L). We conclude that when patients are treated with rifampicin, the standard overnight dexamethasone suppression test not only has no diagnostic value, but can be very misleading.

Adult↗
PubMed1989

Endocrine aspects of menopause.

Oocyte depletion and ovarian aging results in profound alterations at the biological level. The reduction in numbers of follicles leads to reduction of circulating inhibin and increased serum FSH, characteristic marker of ovarian failure. The remaining follicles are overstimulated and premature ovulation may ensue. This, leads to luteal deficiency and reduction in progesterone production and relative hyperestrogenemia. The above changes characterize the premenopausal period. In a second phase, anovulatory cycles interchange with premature and occasionally normal ovulatory cycles. This phase is characterized by increased FSH and LH and decreased progesterone/estradiol ratio resulting in irregular bleeding, endometrial hyperplasia, polyps, fibromas, mammary dystrophies, disturbance of mood, appetite and thermoregulation. Lastly, the sensitivity of ovarian follicles to FSH and LH is lost with a decline of E2 below 20 pg/ml produced almost exclusively from peripheral conversion from circulating androgens. The beneficial effects of E2 are lost resulting in atrophy of the sensitive tissues, decreased calcium absorption, increased bone resorption, accelerated bone loss and osteoporosis, rise in serum triglycerides, increased VLDL and LDL lipoproteins, increased LDL/HDL cholesterol, a profile which favors atherosclerosis.

Aged↗