Abstract
Arterial hypertension is a socially significant disease worldwide, taken to be the commonest risk factor of invalidization and mortality caused by advanced atherosclerosis, left ventricular hypertrophy, myocardial infarction, stroke syndrome and hypoadrenalism.
A number of intricate mechanisms and systems take part in blood pressure regulation and control. Some basic endocrine aspects of such control are discussed. Attention is called to the role of the renin-angiotensin-aldosterone system, adrenocortical and medullary hormones, and hupothalamic-pituitary hormones, with special emphasis laid on the relevance of atrial natriuretic peptides, parathormone and parathyroid hypertensive genic factor, endothelins etc.
In conclusion it is pointed out that the endocrine system has a dominant role in blood pressure regulation through a diversity of functions mediated by hormones, neurotransmitters and local factors.

KEY WORDS: blood pressure, glucocorticoids, mineral corticoids, corticotropin, vasopressin, parathyroid hypertensive genic factor, atrial natriuretic peptides, eicosanoids. 

Abstract
Melatonin is a pineal gland hormone with secretion attributable to the alternation of light and dark periods. 
The effect of light on the human endocrine system is still not well enough clarified. So far, it has been demonstrated that melatonin has an essential practical bearing on synchronizing the circadian rythms of various systems in the human organism upon environmental lighting and darkness alternation. 
This is a hormone underlying the regulation of circadian biological rythms in humans. Thus it exerts definite influence on the homeostasis of the human organism. 
During flights across time zones of 5, 6 and more hours, a swift change in human endocrine system occurs due to circadian rythm impairment. This is a digression referred to in the perinent literature as “jet lag”.

KEY WORDS: melatonin, jet lag, pineal gland, circadian rythm. 

Abstract
It is the purpose of the study to assay the impact of hypogonadism on early bone changes in chronic renal failure (CRF) patients in a predialysis stage. Sixty-nine patients ­ 38 women (aged 42,5±2,8 years) and 31 men (aged 47,3±2,5 years) are covered by the study. In all cases measurements of serum creatinine, total calcium, serum phosphorus, alkaline phosphatase, follicle-stimulating hormone (FSH), estradiol and intact parathormone are done. Dual-energy x-ray absorptiometry is also performed using a “Lunar” apparatus followed by CT evaluation. In female patients presenting hypogonadism (n=22) FSH is 96,92±16,75 IU/l, and estradiol ­ 102,02±31,81 pmol/l. Bone changes occur at different stages in 14 (63,64%) of hypogonad women, while eight are free of bone pathology. Of the total of male patients under study eleven have hypogonadism (FSH=18,13±6,41) and 8 of them present varying degree bone changes, with no effect whatsoever of gonadal dysfunction being documented.
Conclusion. In hypogonad women with initial CRF bone changes are found more often than in those with normal gonad function. In female patiеnts at an advanced stage of CRF there is no statistically significant difference in the rate of bone lesions, but cases of osteoporosis predominate. In uremic male patients no difference in the rate and severity of bone changes attributable to their gonadal function is documented.

KEY WORDS: hypogonadism, osteoden-sitometry, chronic renal failure, renal osteodystrophy.

Abstract
The results of bone mineral density measurements in the forearm of acromegaly patients, using dual-energy x-ray-absorptiometry and some mineral metabolism markers, are discussed. 
The study covers 27 patients (20 women and 7 men) presenting active and controlled acromegaly. The serum levels of total calcium, phosphate, alkaline phosphatase, total ptotein, 24-hour urinary calcium, phosphate and creatinine are evaluated. Bone mineral density (BMD) shows increased values in 12, normal values in 10, and decreased values in 5 cases.
A correlation between BMD and growth hormone (GH) level is established. There is no cor-retation between BMD and hypersomatotropism longstanding.
In conclusion, the increase in bone mass documented among patients with acromegaly points to the practicability of using GH in osteoporosis treatment.

KEY WORDS: acromegaly, growth hormone, bone mineral density, osteoporosis. 

Abstract
24 patients with type 1 diabetes and severe neuropathy were treated with a-lipoic acid  (Thiogamma) for 10 days 600 mg daily i. v., thereafter one film tablet 600 mg daily for 50 days. 20 type 1 diabetic patients with severe neuropathy served as a control group. On the 10th day, we found a decrease of 37% in pain in the treated group, and by the end of the 2nd month it fell by 80% (р<0,001), while in the control group pain changed insignificantly. Vibration perception threshold was reduced in all patients ­ mean 1,79±1,6 at the great toe, 1,95±1,5 at 1st metatarsal, and 3,53±1,2 at medial malleolus in the treated group, and 1,68±1,5, 2,1±1,4 and 3,7±1,5 respectively in the control group. By the end of the second month it reached mean  4,08±1,8 (р<0,001) at the great toe, 4,42±1,7 (р<0,001) at 1st metatarsal and 5,1±0,7 (р<0,001) at medial malleolus in the treated group, and 1,75±1,4 (р>0,8), 1,9±1,6 (р>0,8) and 3,93±1,5 (р>0,6) respectively in the control group. There was a significant improvement after treatment in the index, characterizing the severity of cardiovascular autonomic neuropathy ­ from 7,13±0,7 to 4,75±1,6 (р<0,001) while in the control group it worsened ­ from 6,7±1,1 to 6,95±1,0 (р>0,1). We found improvement in the Valsalva manoeuvre after treatment ­ from 1,06±0,03 to 1,15±0,06 (р<0,001); in deep-breathing test ­ from 2,8±2,1 to 10,0±4,1 (р<0,001); and in the lying-to-standing test ­ from 0,985±0,12 to 1,01±0,10 (р>0,1), while in the control group there was no changes. There was a beneficial effect of treatment on the change of systolic blood pressure in the lying-to-standing test ­ from 20,6±10,8 mm Hg to 9,4±8,8 mm Hg (р<0,001), while in the control group the change was 17,8±9,4 mm Hg and 20,1±10,2 mm Hg (p>0,1), respectively. EMG showed increase in nerve condiction velocity of some nerves in the treated patients. There were changes in the laboratory parameters, characterizing oxidative stress after therapy ­ total serum antioxidative capacity increased from 21,22±1,9 to 23,53±2,0 mg H2O2/ml/min (р<0,05), serum SOD activity ­ from 251,4±29,1 to 323,5±19,9 U/l (р<0,01), and erythrocyte SOD ­ from 0,911±0,102 to 1,130±0,097 U/g Hb (р<0,04). All patients maintained satisfactory control of diabetes throughout the follow-up period. Our results demonstrate that a-lipoic acid  (Thiogamma) appeares to be an effective drug in the treatment of severe peripheral and autonomic diabetic neuropathy.

KEY WORDS: diabetic neuropathy, treatment, a-lipoic acid, autonomic neuropathy. 

Abstract
Diabetic mastopathy is a recently described constellation of histopathological features found in the dense fibrous masses of patients with diabetes mellitus. Fifteen breast biopsy specimens demonstrating nonspecific benign disease from 15 diabetics (13 insulin-independent and 2 insulin-dependent) are examined in a double-blind study without any clinical information. Fifteen age-matched controls are also studied. Age at biopsy varied in the range 20 to 60 years. Slides from each case are investigated for presence of extensive keloid-like fibrosis, mononuclear perivasculitis, mononuclear lobulitis, ductitis and the so-called “epitheloid stromal fibroblasts”.
In compliance with previous reports this constellation of histological characteristic features appear to be relatively specific of diabetic mastopathy. All patients with diabetes mellitus present at least one of the aforementioned histological findings. In the 15 controls none of the four histopathological features characteristic of diabetic mastopathy are documented.
The findings described are in support of the existence of “diabetic mastopathy” among diabetes mellitus patients, and point to the potentially misleading pattern of this benign tumor-like lesion simulating neoplasm or carcinoma.

KEY WORDS: diabetic mastopathy, mastopathy, benign breast disease. 

Abstract
This is a report on the assessment of morbidity rate of diabetes mellitus type 1 among children in Eastern Bulgaria (1/3 of the country’s territory and pediatric population) with analysis of some epidemiologic indicators etiologically relevant for the disease, covering a 25-year period. The study is retrospective for the years 1973-1981, while for the period 1982-1997, the Pediatric Diabetic Registry filing service in Varna performs prospective monitoring of the morbidity rate. In the last 9 years the Registry is affiliated with EURODIAB ACE and DIAMOND. Due to centralized insulin supplementation the case ascertainment is as high as 97,4% for the retrospective, and 98,2% for the prospective part of study. Throughout the observation period, a total of 931 newly affected children, meeting the standard criteria, are identified. The mean annual incidence rate is 6,44/100 000 (95%СI 6,02±6,86), and for the last 10 years ­ 7,87/100 000 (95%СI 7,10±8,66). The rate  is significantly higher among urban, as compared to rural children ­ 7,39/100 000 vs 4,86/100 000 (p<0,001), as well as when analysis is done by age groups  older children (10­14 y) are at greater risk of developing diabetes than younger ones (0­4 y) ­ 8,74/100 000 vs 3,66/100 000, respectively (p<0,001). Only 69 children (7,41%) have I degree relatives with type 1 diabetes. The mean annual morbidity rate is the highest in the Varna county which is the most densely populated ­ 7,33/100 000, and the lowest in the least populated Bourgas county ­ 5,05/100 000 of population.
Poisson’s regression analysis demonstrates a linear trend of increase in morbidity rate in the urban regions with a markedly expressed seasonal character and dependence on the pediatric population density which is a finding most likely attributable to the widespreading of diabetogenic environmental factors, such as viral infections, stress, artificial alimentation with poor quality foodstuffs among the urban pediatric population.

KEY WORDS: type 1 (insulin-dependent) diabetes mellitus, childhood, epidemiology, morbidity rate, urban/rural differences, seasonality.