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Biomedical subjects

E Dimitrov

Publications and source records attributed to E Dimitrov.

9 recordsLinked to original sources
PubMed2000

Prevalence, awareness, treatment and control of hypertension in a working Bulgarian population.

UNLABELLED: Arterial hypertension is a major risk factor for coronary heart disease and stroke mortality. Few data exist on prevalence, awareness, and management of hypertension in Bulgaria, precluding development of potentially beneficial risk reduction initiatives. Between September 1996 and July 1997, an age-sex stratified sample of 847 male and 771 female employees (age 18-64 y) of the national transport industry resident in Sofia was recruited during their annual physical examination. A structured interview was conducted and resting blood pressure (BP) measured. Prevalence: Elevated BP (mean of two consecutive readings SBP > or = 140 mmHg and/or DBP > or = 90 mmHg) was observed among 24% of women and 58% of men (p < 0.001). Prevalence increased with age in both men and women. Awareness: Among 722 employees with elevated BP, 49% of women and 33% of men (p < 0.001) reported history of hypertension. Awareness increased with age. MANAGEMENT: Among 345 employees with history of hypertension, 37% of women and 36% of men (p > 0.05) reported taking antihypertensive treatment. The proportion under management increased with age. CONTROL: Normal BP was measured in only 6% of men and 7% of women taking antihypertensive medication (p > 0.05; no consistent trends by age). Elevated BP is widespread and hypertension is underdiagnosed and poorly controlled in this urban working-age Bulgarian population, especially among those under 40 y. This may contribute to the high rates of coronary heart disease and stroke incidence and mortality in Bulgaria.

Adolescent↗
PubMed1999

[The corticosteroid therapy of premature rupture of the fetal membranes].

Antenatal corticosteroids are now administered for the purpose of hastening maturation of the preterm infant's organs and tissues, thus reducing neonatal mortality and the incidence of respiratory distress syndrome (RDS). Our purpose was to determine the efficacy of maternal corticosteroid therapy on fetal maturation in cases with preterm premature rupture of the membranes. The rates of RDS and survival in low birth weight infants treated with corticosteroids is influenced by the duration of the premature rupture of the membranes and the duration of the corticosteroid therapy, as well as by the gestational age.

Adult↗
PubMed1996

[Cys(O2NH2)2]enkephalin analogues and dalargin: selectivity for delta-opioid receptors.

To investigate the structure-activity relationships for potent and selective action of enkephalins at the delta-opioid receptors, two newly synthesized analogues, [Cys(O2NH2)2,Leu5]enkephalin and [Cys(O2NH2)2, Met5] enkephalin and the hexapeptide [D-Ala2,Leu5]enkephalyl-Arg (dalargin) were tested and compared with [Leu5]enkephalin and [Met5]enkephalin, for their effectiveness to inhibit electrically evoked contractions of the mouse vas deferens (predominantly enkephalin-selective delta-opioid receptors) and the guinea pig ileum (mu- and kappa-opioid receptors). The mouse vas deferens assays included evaluation of the effects of opioid agonists on the first, purinergic, and the second, adrenergic, components of electrically evoked biphasic responses (10 Hz and 20 Hz) and on ATP- or noradrenaline-evoked, tetrodotoxin-resistant responses. The opioids tested inhibited in a similar manner: (i) the purinergic and the adrenergic components of the electrically evoked contractions; and (ii) the ATP- and noradrenaline-induced postjunctional responses of the mouse vas deferens. Extremely low IC50 values (of 2-5 orders) were found for [Cys(O2NH2)2,Leu5] enkephalin, whose relative potency was between 239 and 1316 times higher than that of [Leu5]enkephalin. The order of potency for the other peptides in this tissue was: [Cys(O2NH2)2,Met5]enkephalin > [Leu5]enkephalin > dalargin > [Met5]enkephalin. The highest IC50 values in the guinea pig ileum assays, indicating the lowest affinity for mu-/kappa-opioid receptors, were obtained for the cysteine sulfonamide analogues, while dalargin showed a potency four times higher than that of [Met5]enkephalin. The order of potency in this tissue was: dalargin > [Met5]enkephalin > [Leu5]enkephalin > [Cys(O2NH2)2,Met5]enkephalin > [Cys(O2NH2)2,Leu5]enkephalin. The ratio, IC50 in guinea pig ileum: IC50 in mouse vas deferens, indicating selectivity of the respective peptide for delta-opioid receptors, was extremely high for [Cys(O2NH2)2,Leu5]enkephalin and especially for the adrenergic component of the responses. This ratio for [Cys(O2NH2)2,Met5]enkephalin was higher than the ratios for dalargin, [Leu5]enkephalin and [Met5]enkephalin, which were about 3 orders of magnitude lower. The results suggest that incorporation of hydrophilic Cys(O2NH2) in the enkephalin molecule greatly increases the potency and selectivity of the analogues at delta-opioid receptors, while both D-Ala2 substitution and lengthening of the peptide chain by Arg6 in the molecule of [Leu5]enkephalin decrease them.

Adenosine Triphosphate↗
PubMed1995

Dalargin and [Cys-(O2NH2)]2 analogues of enkephalins and their selectivity for mu opioid receptors.

1. Effects of the enkephalins Met-enk (M) and Leu-enk (L), of two newly synthesized analogues--[Cys-(O2NH2)]2-Met-enk (CM) and [Cys-(O2NH2)]2-Leu-enk (CL)--and of a hexapeptide--D-Ala2-Leu5-Arg6 (Dalargin; DL) on the spontaneous and electrically stimulated activity were examined with respect to their selectivity for the mu opioid receptors in the longitudinal layer of guinea pig ileum. 2. M and CM exerted relaxing and contractile effects on the spontaneous contractile activity while L, CL and DL produced only relaxation. The order of potency towards the relaxatory phase was DL > M > CM > L > CL and towards the contractile phase CM > M. 3. The effects of enkephalins on the spontaneous activity were naloxone and TTX sensitive except for the contractile phase of M and CM which persisted in the presence of TTX. NO was not involved in the neurotransmission of the relaxatory responses, while the blockade of alpha and beta adrenoceptors showed the participation of adrenergic mechanisms. Relaxation and contraction induced by enkephalins could not be directly attributed to cholinergic neurotransmission. 4. The naloxone-sensitive and concentration-dependent inhibitory effects of enkephalins and their analogues on the electrically stimulated cholinergic contractions were established. The order of the relative potency of opioids was: DL-3.8; M-1.0; L-0.4; CM-0.01; CL-0.005. 5. These data indicated that the D-Ala2 substitution and lengthening of the peptide chain by Arg6 in the molecule of L increased the potency at the mu opiate receptors, while the substitution in position 2 with Cys-(O2NH2) in the molecule of M and L yielded a less potent and selective mu agonists.

Amino Acid Sequence↗
PubMed1990

Diagnosis and management of paragangliomas of the skull base.

In appropriately selected patients, glomus tumors of the head and neck are best treated surgically. Unresectability is not a factor in therapeutic planning for local disease control. Existing techniques and exposures for tumor removal can be reliably applied to these paragangliomas, with acceptable morbidity and mortality. A team approach to this problem is mandatory.

Adult↗
PubMed1987

Hyaluronic acid production and hyaluronidase activity in the newt iris during lens regeneration.

The process of lens regeneration in newts involves the dedifferentiation of pigmented iris epithelial cells and their subsequent conversion into lens fibers. In vivo this cell-type conversion is restricted to the dorsal region of the iris. We have examined the patterns of hyaluronate accumulation and endogenous hyaluronidase activity in the newt iris during the course of lens regeneration in vivo. Accumulation of newly synthesized hyaluronate was estimated from the uptake of [3H]glucosamine into cetylpyridinium chloride-precipitable material that was sensitive to Streptomyces hyaluronidase. Endogenous hyaluronidase activity was determined from the quantity of reducing N-acetylhexosamine released upon incubation of iris tissue extract with exogenous hyaluronate substrate. We found that incorporation of label into hyaluronate was consistently higher in the regeneration-activated irises of lentectomized eyes than in control irises from sham-operated eyes. Hyaluronate labeling was higher in the dorsal (lens-forming) region of the iris than in ventral (non-lens-forming) iris tissue during the regeneration process. Label accumulation into hyaluronate was maximum between 10 and 15 days after lentectomy, the period of most pronounced dedifferentiation in the dorsal iris epithelium. Both normal and regenerating irises demonstrated a high level of endogenous hyaluronidase activity with a pH optimum of 3.5-4.0. Hyaluronidase activity was 1.7 to 2 times higher in dorsal iris tissue than in ventral irises both prior to lentectomy and throughout the regeneration process. We suggest that enhanced hyaluronate accumulation may facilitate the dedifferentiation of iris epithelial cells in the dorsal iris and prevent precocious withdrawal from the cell cycle. The high level of hyaluronidase activity in the dorsal iris may promote the turnover and remodeling of extracellular matrix components required for cell-type conversion.

Animals↗