Effect of exogenous melatonin on vascular reactivity and nitric oxide in postmenopausal women: role of hormone replacement therapy

OBJECTIVE: Several effects of melatonin are modulated by gonadal steroids and are reduced in ageing women. Administration of melatonin reduces internal carotid artery pulsatility index (PI), and blood pressure in young individuals. Whether these effects are conserved in postmenopausal women and are influenced by hormone replacement therapy (HRT), was herein investigated. DESIGN: Randomised, double-blind placebo controlled study. PATIENTS: Twenty-three postmenopausal women of which 11 were unreplaced with HRT and 12 on the oestrogenic phase of continuous transdermal estradiol (50 microg/day) plus cyclic medroxyprogesterone acetate (5 mg/day x 12 days every 28 days). MEASUREMENTS: Internal carotid PI, by colour Doppler, and supine blood pressure were evaluated 90, 180 and 240 minutes following the oral administration of melatonin (1 mg) or placebo. Levels of nitrites/nitrates (NOx), the stable derivatives of nitric oxide, were also evaluated in samples collected 90 minutes following the administration of placebo or melatonin. RESULTS: In women not on replacement therapy melatonin was ineffective. In HRT-treated women, melatonin reduced internal carotid artery PI (P = 0.005). The effect was maximal within 90 minutes, and maintained for at least 240 minutes, with melatonin levels in the nocturnal physiological range. Systolic and diastolic blood pressures were reduced of 8 mmHg (P = 0.038) and 4 mmHg (P = 0.045), respectively, while NOx levels were significantly increased (P = 0.024). CONCLUSIONS: The circulatory response to melatonin is conserved in postmenopausal women with but not without hormone replacement therapy. Maintenance of the cardiovascular response to melatonin, may be implicated in the reduced cardiovascular risk of postmenopausal women with hormone replacement therapy.     

Influence of the needle bore size on platelet count and routine coagulation testing.

The phlebotomy technique, particularly the use of small-bore needles, may influence the reliability of coagulation testing and platelet count. Routine coagulation tests were assayed in blood specimens collected from 22 consecutive patients in three separate, sequential phlebotomies, using butterfly devices with different needle sizes. Test results of samples collected with 23 and 25 G needles were compared with those obtained with the currently recommended 21 G needle. Although both the prothrombin time and activated partial thromboplastin time displayed a trend towards lower values employing the smaller 23 and 25 G needles, results did not differ significantly from the reference 21 G needle specimen, with the exceptions of D-dimer (25 G versus 21 G needle, 186 +/- 70 versus 178 +/- 66/ml, P < 0.01) and platelet count (23 G versus 21 G needle, 246 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01; 25 G versus 21 G needle, 240 +/- 55 versus 254 +/- 56 x 10(-3)/l, P < 0.01). None of the mean biases recorded for the parameters was clinically meaningful, nor did they exceed the current desirable analytical quality specifications for desirable bias. Results of the present investigation suggest that, when a proper technique is used and within certain limitations, butterfly devices with small-bore needles may be a reliable alternative to draw venous blood for platelet count and coagulation testing.     

Ras activation in myelodysplastic syndromes: clinical and molecular study of the chronic phase of the disease

We studied N-ras and Ki-ras point mutations respectively at codons 12-13 and 12 in 15 patients with myelodysplastic syndromes (MDS) using the polymerase chain reaction (PCR) method for DNA amplification, and slot blot hybridization to allele specific oligonucleotide (ASO) probes. We analysed peripheral blood and bone marrow samples collected at diagnosis and repeatedly during the chronic phase of the disease to define when the activation occurred and in which haemopoietic cell populations, in order to establish possible relationships between clinical and molecular features. In three cases the N-ras oncogene was mutated at codon 12 in every cell population, both at diagnosis and throughout the chronic phase. Point mutations were not seen at the 12 codon of the Ki-ras oncogene. In patients lacking activated ras oncogene at diagnosis, mutations were not discovered during the entire period of observation. Therefore in our cases disease progression and leukaemic transformation did not correlate with the presence of the activated N-ras. Our data suggest that ras activation occurs early in the pathogenesis of MDS and involves a haemopoietic progenitor with multiple differentiative capacity, without however conferring an apparent proliferative advantage on its progeny.     

Relationship between serum erythropoietin levels and rT3, T4 concentrations in elderly patients with non-thyroidal illnesses

Thyroid function, plasma erythropoietin and tumor necrosis factor (TNF-alpha) concentrations were measured in 28 elderly patients with chronic non-thyroidal illnesses (NTI) and in 8 healthy subjects as a control group. In the NTI group, the existence of an impairment of thyroid function has been demonstrated in about 85% of the subjects, with a lower T(3) concentration; a low T(3) syndrome with low T(3) levels and high reverse-T(3) (rT(3)) plasma concentrations could be found in 25% of the subjects. A direct correlation between erythropoietin and rT(3) and an inverse correlation between erythropoietin and T(4) were found on NTI patients with endocrine abnormalities.     

Increased expression of leukocyte function associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) by alveolar macrophages of patients with pulmonary sarcoidosis.

Leukocyte function associated antigen-1 (LFA-1) and its ligand intercellular adhesion molecule-1 (ICAM-1) are cell adhesion molecules that play an important role in the capacity of monoculear phagocytes (MPs) to present antigens to T lymphocytes. Since in pulmonary sarcoidosis (PS) this capacity is increased at sites of disease activity, we studied the expression of LFA-1 and ICAM-1 on peripheral blood monocytes (BMs) and alveolar macrophages (AM) obtained by bronchoalveolar lavage (BAL) from normal subjects (n = 7) and patients with PS (n = 14). To accomplish this, immunocytochemical stainings were made on cytocentrifuge preparations using anti-LFA-1 (anti-CD 11a) and anti-ICAM-1 (anti-CD 54) monoclonal antibodies (MoAbs). Normal and sarcoid BMs displayed a high percentage of positivity with both MoAbs with no difference between study groups (LFA-1: control BM 87.8 +/- 8.8 percent; sarcoid BM 84.7 +/- 9.5 percent; ICAM-1: control BM 80.8 +/- 10 percent; sarcoid BM 88.0 +/- 4.2 percent; p = NS for all comparisons). In both groups the percentage of cells expressing LFA-1 and ICAM-1 molecules among AMs was lower than among autologous BMs (LFA-1: control AM 46.5 +/- 13.2 percent, p less than 0.001 vs control BM; sarcoid AM 64.2 +/- 15.9; p less than 0.001 vs sarcoid BM) (ICAM-1: control AM 42.7 +/- 8.5 percent, p less than 0.001 vs control BM; sarcoid AM 72.1 +/- 10.6, p less than 0.001 vs sarcoid BM). AMs from patients with PS showed a higher degree of positivity for LFA-1 and ICAM-1 than normal AMs (p less than 0.02 and p less than 0.001, respectively). The positivity for LFA-1 and ICAM-1 molecules on sarcoid AMs was not correlated with the positivity for two different BM-associated markers (ie, the CD 11b and the CD 14 molecules) and was not correlated with the percentage of T lymphocytes in BAL, selected as a marker of the intensity of the alveolitis. These results suggest that the increased ability of sarcoid AMs to induce the proliferation of T lymphocytes may be related, at least in part, to the increased expression of LFA-1 and ICAM-1 molecules on their surfaces.     

Reinfection and mixed infection cause changing Mycobacterium tuberculosis drug-resistance patterns

RATIONALE: Multiple infections with different strains of Mycobacterium tuberculosis may occur in settings where the infection pressure is high. The relevance of mixed infections for the patient, clinician, and control program remains unclear. OBJECTIVES: This study aimed to describe reinfection and mixed infection as underlying mechanisms of changing drug-susceptibility patterns in serial sputum cultures. METHODS: Serial M. tuberculosis sputum cultures from patients diagnosed with multi-drug-resistant (MDR) tuberculosis were evaluated by phenotypic drug-susceptibility testing and mutation detection methods. Genotypic analysis was done by IS6110 DNA fingerprinting and a novel strain-specific polymerase chain reaction amplification method. MEASUREMENTS AND MAIN RESULTS: DNA fingerprinting analysis of serial sputum cultures from 48 patients with MDR tuberculosis attributed 10 cases to reinfection and 1 case to mixed infection. In contrast, strain-specific polymerase chain reaction amplification analysis in 9 of the 11 cases demonstrated mixed infection in 5 cases, reinfection in 3 cases, and laboratory contamination in 1 case. Analysis of clinical data suggests that first-line therapy can select for a resistant subpopulation, whereas poor adherence or second-line therapy resulted in the reemergence of the drug-susceptible subpopulations. CONCLUSIONS: We have shown that, in some patients with MDR tuberculosis, mixed infection may be responsible for observations attributed to reinfection by DNA fingerprinting. We conclude that treatment and adherence determines which strain is dominant. We hypothesize that treatment with second-line drugs may lead to reemergence of the drug-susceptible strain in patients with mixed infection.     

Adrenocorticotropic hormone and catecholamines in maternal, umbilical and neonatal plasma in relation to vaginal delivery

The aim of this study was to evaluate the effect of vaginal delivery on both ACTH and catecholamines (DA, NE, E) secretion in the mother, the fetus (umbilical artery) and the newborn. Blood samples were obtained from 19 normal pregnant women and the corresponding umbilical cords, and from the newborns. Seventeen normal nonpregnant women, matched for age and parity, were also included in the study as "nonpregnant controls". The results demonstrate that in the mother, plasma catecholamines (CA) concentrations during labor and delivery are elevated above the values reported for normal nonpregnant women and there is a predominant E response. The concentrations of CA in umbilical arteries are very high compared to those in the corresponding mother and they fall rapidly after birth. Unlike that in the mother, the predominant CA response to parturition in the fetus and newborn infant is NE. The extraction rate of DA, NE and E from placenta is approximately 60%. The peripheral plasma levels of ACTH in pregnant women during labor are twice and 10 times as high as those observed in the corresponding umbilical arteries and in nonpregnant women respectively. At delivery they increase further. No significant differences are found between the values measured in the arterial cord blood and those in the venous cord blood and in the newborns. A way of explaining the prevalence of E and the higher ACTH/E ratio found in the mother in comparison with the fetus could be that in the mother the stress response to parturition is regulated mainly by the pituitary-adrenal axis, whereas in the fetus there is a prevalent stimulation of the sympathetic nervous system.     

Effects of transdermal estrogen administration on peripheral vascular responsiveness in menopausal women

This study was designed to evaluate the peripheral vascular responses to acute estrogen replacement. According to a cross-over, double-blind study design, we randomized nine healthy postmenopausal women (time lapse from menopause to >1 year; mean age±SD 45.4±11.7 years) to treatment with transdermal patches of estradiol-17 or matched placebo. The estrogen patch was rated to assure a plasma concentration of substance of more than 100 pg/ml after 8–10 hours of treatment. Forearm blood flow (ml/100 ml/minute), local vascular resistance (mmHg/ml/100 ml/minute), venous volume (ml/100 ml), and venous compliance (ml/100 ml/mmHg) were measured in supine resting subjects by the straingauge venous occlusion plethysmography. Plasma concentration of norepinephrine (pg/ml) was quantified by HPLC-ED. Estradiol-17 produced increase in forearm blood flow and decrease in local vascular resistance. The drug reduced circulating norepinephrine concentrations. There were no significant changes in mean arterial pressure or heart rate. Venous volume and venous compliance were both enhanced by estrogen administration. The peripheral circulatory changes are attributed to a direct activity of estradiol-17 on arterial and venous wall and may in part reflect a modulation of estrogen on peripheral sympathetic tone.