Melatonin the "light of night" in human biology and adolescent idiopathic scoliosis

Melatonin "the light of night" is secreted from the pineal gland principally at night. The hormone is involved in sleep regulation, as well as in a number of other cyclical bodily activities and circadian rhythm in humans. Melatonin is exclusively involved in signalling the 'time of day' and 'time of year' (hence considered to help both clock and calendar functions) to all tissues and is thus considered to be the body's chronological pacemaker or 'Zeitgeber'. The last decades melatonin has been used as a therapeutic chemical in a large spectrum of diseases, mainly in sleep disturbances and tumours and may play a role in the biologic regulation of mood, affective disorders, cardiovascular system, reproduction and aging. There are few papers regarding melatonin and its role in adolescent idiopathic scoliosis (AIS). Melatonin may play a role in the pathogenesis of scoliosis (neuroendocrine hypothesis) but at present, the data available cannot clearly support this hypothesis. Uncertainties and doubts still surround the role of melatonin in human physiology and pathophysiology and future research is needed

Association between adolescent idiopathic scoliosis prevalence and age at menarche in different geographic latitudes

BACKGROUND: Age at menarche is considered a reliable prognostic factor for idiopathic scoliosis and varies in different geographic latitudes. Adolescent idiopathic scoliosis prevalence has also been reported to be different in various latitudes and demonstrates higher values in northern countries. A study on epidemiological reports from the literature was conducted to investigate a possible association between prevalence of adolescent idiopathic scoliosis and age at menarche among normal girls in various geographic latitudes. An attempt is also made to implicate a possible role of melatonin in the above association. MATERIAL-METHODS: 20 peer-reviewed published papers reporting adolescent idiopathic scoliosis prevalence and 33 peer-reviewed papers reporting age at menarche in normal girls from most geographic areas of the northern hemisphere were retrieved from the literature. The geographic latitude of each centre where a particular study was originated was documented. The statistical analysis included regression of the adolescent idiopathic scoliosis prevalence and age at menarche by latitude. RESULTS: The regression of prevalence of adolescent idiopathic scoliosis and age at menarche by latitude is statistically significant (p < 0.001) and are following a parallel declining course of their regression curves, especially in latitudes northern than 25 degrees. CONCLUSION: Late age at menarche is parallel with higher prevalence of adolescent idiopathic scoliosis. Pubarche appears later in girls that live in northern latitudes and thus prolongs the period of spine vulnerability while other pre-existing or aetiological factors are contributing to the development of adolescent idiopathic scoliosis. A possible role of geography in the pathogenesis of idiopathic scoliosis is discussed, as it appears that latitude which differentiates the sunlight influences melatonin secretion and modifies age at menarche, which is associated to the prevalence of idiopathic scoliosis

INCIDENCE AND CHARACTERISTICS OF MICROPROLACTINOMAS (3-5 MM) IN 4199 WOMEN ASSAYED FOR PROLACTIN

Difficulties and controversies still exist in the diagnosis of small (3-5 mm) prolactinomas (micro-PRL-omas). In the present study serum prolactin (PRL) was assayed in 4199 women aged 14-43 years belonging to 4 groups: A: 753 women with normal cycles (NC) and infertility (control group), B: 2523 with menstrual disorders, C: 519 with NC and hirsutism, D: 404 with galactorrhoea. The distribution of PRL values from 1 to 30 ng/ml was almost similar in the subjects of group A, B and C. Within this range the vast majority of subjects (91 %, 92.2 % and 88% respectively in these 3 groups and 83 % in group D) had PRL levels from 1 to 15 ng/ml and together with the proportion of subjects with PRL values 16 to 20 ng/ml they included 96.7 % of the entire mixed population. A proportion of scattered outlying PRL values above 30 ng/ml was found in each group (A = 2%, B = 3%, C = 1% and D = 28.7 %) and in this subset 117 prolactinomas (PRL-omas) were found, 19 (23%) in the 83 subjects with PRL levels 31-49 ng/ml and 98 (75.3%) in the 130 subjects with PRL values greater-than-or-equal-to 50 ng/ml. Of the 117 PRL-omas 9 were bigger than 10 mm and 4 had a size from 6 to 9 mm. In the remaining 104 the size was presumed from direct or indirect radiological evidence to be 3 - 5 mm. The age of the patients ranged from 14-43 yrs with a greater prevalence of the younger ages (38% consulted and 56.5% manifested their symptoms before the age of 26 yrs). Provocative tests performed in 37 patients and in 37 subjects with non-tumorous hyperPRL-aemia (NT-HyperPRL) gave ambiguous results when basal PRL ranged from 30 to 49 ng/ml but the response was negative in all cases with micro-PRL-oma and in the majority of cases with NT-HyperPRL when basal PRL was 50-100 ng/ml. Independently of PRL levels, the patients with micro-PRL-omas presented with all the spectrum of menstrual disorders. Secondary amenorrhoea was the most common symptom (46%). Thirteen patients (12.5%) presenting with menses of normal length had PRL varying from 30 to 100 and in one case up to 230 ng/ml. Galactorrhoea was found in 63.5 % of the patients with micro-PRL-omas. However, 1/3 of the patients with high PRL levels (&gt; 50 ng or &gt; 100 ng) did not have spontaneous or provoked galactorrhoea at the time of the examination

Corticotropin-releasing-hormone levels in pregnancy-induced hypertension

High levels of corticotropin-releasing hormone (CRH) circulate in the plasma of pregnant women especially during the third trimester and even higher levels have been reported in abnormal pregnancies of various etiologies. One of these etiologies is pregnancy-induced hypertension (PIH). Objective: To measure CRH blood levels with a sensitive method in a large number of pregnant women with PIH, starting from very early stages of gestation, and to compare them with those in normal controls. Study design: Venous blood was withdrawn from, (a) 10 healthy women aged 20-35 years, (b) 62 pregnant women with PIH (109 samples), mean age 29.1 years and (c) 75 healthy pregnant women (81 samples), mean age 28.5 years, used as matched controls. In pregnant women, blood collection started at the 10th week of gestation. In 14 women from group b and in 22 from group c blood was withdrawn during labor as well. CRH was assayed by RIA. Results: Levels in non-pregnant women were between 19.0-40.6 pg/ml (28.37 +/- 2.53 pg/ml, mean +/- S.E.M.). In both groups of pregnant women there was a progressive increase in plasma CRH levels becoming quite sharp towards the end of gestation. Between 10 and 20 weeks, CRH (mean +/- S.E.M.) in PIH group was 69.3 +/- 3.2 pg/ml versus 41.6 +/- 2.4 pg/ml in matched controls, at 21-25 weeks 168.0 +/- 12.8 pg/ml versus 58.5 +/- 3.8 pg/ml, at 32-35 weeks 1378.5 +/- 61.4 pg/ml versus 298.3 +/- 16.9 pg/ml and at 38 weeks 2800.0 +/- 114.1 pg/ml versus 825.0 +/- 59.8 pg/ml. At term, CRH levels were 3784.0 +/- 197.3 pg/ml in PIH, versus 1386.0 +/- 101.8 pg/ml in normal pregnancy. Statistically, at every stage of gestation, CRH levels were highly significantly different in the PIH group (P &lt; 0.0005). One hour postpartum there was a c. 60% decrease in plasma CRH levels in both b and c groups. In three women with pre-eclampsia who underwent premature labor due to a dead fetus around the 30th week, very high levels were noticed in sequential blood samples for 4-5 weeks prior to labor. Conclusions: (a) CRH levels in women with PIH are significantly higher compared to healthy pregnant women at any stage of gestation starting from week 10; (b) very high levels during pregnancy might be predictive of premature labor or fetal loss; and (c) CRH measurement might prove to be a helpful diagnostic tool in women with pregnancy-induced hypertension