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Biomedical subjects

N Lazarov

Publications and source records attributed to N Lazarov.

At least 19 recordsLinked to original sources
PubMed2003

[Our experience with cedax (ceftibuten) in the obstetrical and gynecological practice].

Cedax is an oral third generation cephalosporin for use with a wide spectrum of antibacterial activity. It has been made a comparative study between Cedax and other third generation cephalosporins in 40 pregnant women with asymptomatic bacteriuria. The authors made a conclusion Cedax is a preferred antibacterial drug for treatment of similar infections of pregnancy because of his easy application way and the absence of side effects.

Administration, Oral↗
PubMed2001

Classical and nonclassical estrogen action in the developing midbrain.

There is widespread acceptance that estrogen is involved in various steps of cellular differentiation during brain development. In the past years, we have demonstrated such a developmental role for estrogen in the rodent midbrain. Precisely, estrogen affects midbrain dopamine neurons with respect to functional and morphological maturation. On the cellular level, estrogen may act classically by binding and activating its respective nuclear receptors, thereby controlling the transcription of target genes. On the other hand, many estrogen effects in the CNS are transmitted nonclassically by interactions with putative membrane receptors and by stimulating distinct intracellular signaling cascades. In the midbrain, classical and nonclassical estrogen signaling routes operate side by side to ensure the proper development of dopaminergic cells. In the present report, we detail some of the cellular and molecular events which are activated by estrogen and are thought to take part in the estrogen-mediated stimulation of dopamine neuron differentiation.

Animals↗
PubMed2001

[Peripartal hysterectomy].

In the present investigation the authors review 37 cases of peripartal hysterectomy, made in our clinic for a 10 year period. The results show that there is a high risk intervention, because of the massive blood loss and altered anatomical structure.

Adult↗
PubMed2001

[Hysteroscopic diagnosis of endometrial carcinoma].

Searching of more effective methods for early diagnosis of Endometrial Cancer has confirmed the hysteroscopy as most complete and sufficient manner in this direction. In the present exposition the authors are sharing their experience and making some practical conclusions that may be useful for the physicians applying this method.

Adult↗
PubMed2000

Vitiligo-related neuropeptides in nerve fibers of the skin.

Skin distribution of substance P (SP)-, somatostatin (SOM)-, calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (LI) in vitiligo patients was studied by an indirect immunofluorescence technique. Immunocytochemical characteristics of the epidermis, dermal-epidermal junction, papillary and reticular dermis and skin appendages were analyzed in lesional and marginal vitiligo areas, as well as in healthy skin. In healthy pigmented skin, SP-, SOM-, CGRP-, and NPY-LI nerve fibers were observed with specific distributional patterns. In uninvolved vitiligo skin, thin SP-containing fibers were evident in dermal papillae, extending into the epidermis, and SP-LI fibers were seen around blood vessels and sweat glands. SOM-LI varicose nerve fibers were associated with Meissner corpuscles in the dermal papillae, while CGRP-LI was demonstrated in the free subepidermal nerve terminals and in sensory nerve fibers around blood vessels, hair follicles and sweat glands. Autonomic NPY-nerve fibers innervated the eccrine sweat glands and blood vessels. The distribution of these neuropeptides in both marginal and lesional areas of vitiliginous skin was the same as in the skin of healthy control subjects, except for an increased immunoreactivity against NPY and, to a lesser extent, against CGRP in the skin depigmentation lesions. The elevated NPY levels in skin affected by vitiligo suggest that this peptide may serve as a neurochemical marker in the pathogenesis of the disease, thus supporting the neuronal theory of vitiligo.

Adult↗
PubMed2000

Markers for vitiligo related neuropeptides in human skin nerve fibers.

Skin distribution of substance P (SP)-, somatostatin (SOM)-, calcitonin-gene-related peptide (CGRP)- and neuropeptide-Y (NPY)-like immunoreactivity in vitiligo patients was studied by an indirect immunofluorescence technique. Immunocytochemical characteristics of the epidermis, dermoepidermal junction, papillary and reticular dermis, and skin appendages were analyzed in lesional and marginal vitiligo areas as well as in healthy skin. SP-, SOM-, CGRP-, and NPY-immunoreactive nerve fibers were observed in healthy pigmented skin, with patterns specific for immunoreactive distribution. Thin SP-containing fibers were observed in dermal papillae, extending into the epidermis, and SP-immunoreactive nerve fibers were seen around blood vessels and sweat glands. SOM-immunoreactive varicose nerve fibers were associated with Meissner's corpuscles in dermal papillae, while CGRP-like immunoreactivity was demonstrated in free subepidermal nerve terminals and sensory nerve fibers around blood vessels, hair follicles and sweat glands. Autonomic NPY-containing nerve fibers innervated eccrine sweat glands and blood vessels. The distribution of these neuropeptides was the same in healthy controls, except for an increased immunoreactivity to NPY and to a lesser extent to CGRP. These results suggest that NPY may serve as a neurochemical marker in the pathogenesis of the disease, thus supporting the neuronal theory of vitiligo.

Calcitonin Gene-Related Peptide↗
PubMed2000

[Parovarian cyst in an 18-year-old patient].

A rare case of a large paraovarian cyst in an unusually young 18-age-old patient, filling up the whole abdominal cavity, is described. It is concluded that an accurate and precise diagnostics, and also an experienced surgical team would be required in such a surgery as complete surprises can take place effecting its course and outcome.

Adolescent↗
PubMed1998

GABA- and glutamate-immunoreactivity in sensory ganglia of cat: a quantitative analysis.

Several amino acids may function as neurotransmitters in the nervous system. The potential role of glutamate (Glu) and aspartate in excitatory responses was demonstrated and it was established that GABA and glycine act as inhibitory agents. The present study aimed at investigating the availability of Glu and GABA in certain feline sensory ganglia, i.e. the trigeminal (TrG), nodose and dorsal root ganglia (DRG). A significant part of the neurons were GABA-positive (19.5% to 23.5%). These were large-sized neurons as well as small- to medium-sized ones. The intensity of immunostaining varied from weak to strong. GABA-containing neuronal fibres were seen in the neuropil and some of them surrounded unstained ganglionic cells. The Glu-immunoreactive (IR) neuronal perikarya in all the investigated ganglia were 63.6% to 66.4%. The majority of positive cells were small- to medium-sized, but large primary sensory neurons were also seen. There was no difference between the intensity of the reaction in the primary sensory and small neurons. Glu-IR neuronal fibres were seen in close apposition to immunopositive as well as immunonegative neurons. In conclusion, in the TrG, nodose and DRG, GABA and glutamate are involved in neurotransmission. There is a significant number of GABAergic neurons in the investigated sensory ganglia of the cat. The difference in the expression of these amino acids suggests that they can act not only as neurotransmitters but also as modulators of sensory information.

Animals↗
PubMed1998

Distribution of NADPH-diaphorase and nitric oxide synthase in the trigeminal ganglion and mesencephalic trigeminal nucleus of the cat. A histochemical and immunohistochemical study.

The trigeminal ganglion (TrG) and mesencephalic trigeminal nucleus (MTN) neurons are involved in the transmission of orofacial sensory information. The presence of nitric oxide (NO), a putative neurotransmitter substance in the nervous system, was examined in the cat TrG and MTN using nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry and nitric oxide synthase (NOS) immunohistochemistry. In the TrG, where the majority of the trigeminal primary afferent perikarya are located, most of the intensely NADPH-d/ NOS-stained cells were small in size and distributed randomly throughout the ganglion. The medium-sized neurons were moderately stained. A plexus of pericellular varicose arborizations around large unstained ganglion cells and densely stained fibers in-between could also be observed. In the caudal part of the MTN, both NADPH-d activity and NOS immunoreactivity was present in MTN neurons. In addition, a few scattered NADPH-d/NOS-containing neurons were found in the mesencephalic-pontine junction part of the nucleus. In contrast, only nerve fibers and their terminals were present at a more rostral level in the mid- and rostral MTN. MTN neuronal perikarya were enveloped in fine basket-like NADPH-d/ NOS-positive networks. Differential expression patterns of NOS and its marker NADPH-d suggest that trigeminal sensory information processing in the cat MTN is controlled by nitrergic input through different mechanisms. We introduce the concept that NO can act as a neurotransmitter in mediating nociceptive and proprioceptive information from periodontal mechanoreceptors but may also participate in modulating the activity of jaw-closing muscle afferent MTN neurons.

Animals↗
PubMed1997

Localization of D1 and D2 dopamine receptors in the rat mesencephalic trigeminal nucleus by immunocytochemistry and in situ hybridization.

The rat mesencephalic trigeminal nucleus (MTN) receives a dopaminergic innervation. In order to identify and localize dopaminoceptive cells within this nucleus, expression of D1 and D2 dopamine (DA) receptors was examined by immunocytochemistry with subtype-specific antibodies and in situ hybridization with digoxigenin-labeled cRNA probes. Immunocytochemical labeling was restricted to neuronal perikarya and proximal processes whereas the hybridization signal was confined to MTN cell bodies. Cells immunopositive for D1 were located throughout the entire MTN whereas cells labeled with D2 antibodies were concentrated in its caudal portion. D1 receptor message was found in relatively low levels. In contrast, high levels of mRNA for D2 were seen in MTN neurons. The distribution of DA receptor mRNA-containing cells were very similar to those of DA receptor immunoreactivity. Neurons expressing the D1 receptor gene were localized in both rostral and caudal portions, which receive inputs from masticatory muscle spindles and from spindles and periodontal ligament receptors, respectively. D2 receptors were limited to ventrocaudally located cells. These results suggest that processing of proprioceptive information in the MTN is controlled by the DAergic input through different postsynaptic mechanisms.

Animals↗
PubMed1996

Pre- and postnatal development of dopaminergic neuron numbers in the male and female mouse midbrain.

Quantitative information about dopaminergic neuron numbers in the mesencephalon is needed to assess the significance of physiological cell death in the regulation of the development of this neural system. Therefore, stereological techniques were applied to determine absolute numbers of mesencephalic neurons immunoreactive to tyrosine hydroxylase during the ontogenetic period between embryonic day (E) 13 and postnatal day (P) 90. Male and female CBA/J mice were examined separately. The most rapid development with a 2.5-fold increase of total counts of immunostained cells per midbrain took place in the prenatal period. Beginning at E21, immunostained cells were counted separately in their three main locations, substantia nigra (SN), ventral tegmental area (VTA), and retrorubral field (RRF). Neuron numbers in RRF and VTA reached adult levels perinatally. In contrast, counts of immunostained cells in SN continued to increase postnatally. The only sign of cell loss was a transient decrease in VTA cell numbers (but not in total numbers of immunostained midbrain neurons) between E21 and P14. There were no statistically significant sex differences in cell numbers at any time point investigated. It is concluded that physiological cell death is not a major factor in the developmental regulation of dopaminergic cell numbers in the mouse midbrain.

Animals↗
PubMed1996

Fine structure and synaptic organization of the mesencephalic trigeminal nucleus of the cat: a quantitative electron microscopic study.

The ultrastructure and synaptic organization of the mesencephalic trigeminal nucleus (MTN) were studied in adult cats by transmission electron microscopy and more precisely quantified with an automated image analysis system. Two subpopulations of MTN neurons were identified within the nucleus: large spherical or ovoid (pseudo)unipolar cells amounted to about 60% of the total population that resemble typical primary sensory neurons and small multipolar neurons (estimated 40%), some of which are possibly interneurons. By electron microscopy, most neurons in the MTN proved to have a rich cytoplasm in the perikaryon with abundant rough endoplasmic reticulum, a large number of free ribosomes and polysomes, also well-developed Golgi complex, and numerous mitochondria and neurofilaments indicating a high rate of protein synthesis and axonal transport in these cells. Three types of synaptic contacts were observed in the MTN: axodendritic, axosomatic and axospinic of both symmetric and asymmetric morphology. Most of them (almost 90%) were axodendritic and axodendritic spine. Approximately 70% of axon terminals contained small round vesicles (S-type boutons) whereas the other 30% belonged to the P-type boutons filled with a pleomorphic vesicle population. Axosomatic synapses were comparatively rare accounting for 10% of the total. About two-third of them were of S-type and almost 25% of the remaining third were F-type in which flat synaptic vesicles could be seen, and less than 10% were P- and G-types with granular vesicles.

Animals↗
PubMed1995

Distribution of calcitonin gene-related peptide- and neuropeptide Y-like immunoreactivity in the trigeminal ganglion and mesencephalic trigeminal nucleus of the cat.

The distribution of calcitonin gene-related peptide (CGRP)- and neuropeptide Y (NPY)-like immunoreactivity (LI) in the cat trigeminal ganglion (TrG) and mesencephalic trigeminal nucleus (MTN) was studied by the indirect immunofluorescent technique and unlabelled peroxidase-antiperoxidase method. A positive reaction for both CGRP and NPY was found only in the TrG primary afferent neurons. Between 40% and 50% of the perikarya displayed CGRP-LI whereas few of the trigeminal principal neurons (approximately 1%) showed NPY-LI. Most of the CGRP-immunoreactive cells were small to medium-sized (20-40 microns in diameter) and were distributed throughout the ganglion. NPY appeared specifically in medium-sized to large-sized trigeminal neurons (up to 60 microns). CGRP and NPY also occurred in varicose nerve fibres running among the cell bodies and in pericellular baskets around a small number of large unstained ganglion cells. In contrast, CGRP- and NPY-LI were present only in the nerve fibres and terminals of the cat MTN. The immunoreactive varicosities travelled towards the negative MTN neurons and formed basket-like arborizations around their cell bodies. Synaptic contact between the immunolabelled axonal profiles and perikarya of trigeminal primary afferent neurons could not be seen in the TrG and MTN of the cat. The results provide further evidence for the interrelation between sensory and autonomic systems.

Animals↗
PubMed1994

Primary trigeminal afferent neuron of the cat: II. Neuropeptide- and serotonin-like immunoreactivity.

The distribution of several peptides and serotonin in the cat vibrissa primary afferents from the Merkel cell-axon complexes to their central projections in the principal trigeminal sensory nucleus was examined by peroxidase-antiperoxidase immunocytochemical technique. In the trigeminal ganglia, two populations of primary sensory neurons, containing immunoreactive material were identified: a few substance P-, bombesin-, somatostatin-, cholecystokinin-, and vasoactive intestinal polypeptide-like immunoreactive ganglion cells with small and medium-sized somata, and many large non-labelled trigeminal neurons that were surrounded by substance P-, somatostatin-, cholecystokinin-, vasoactive intestinal polypeptide- and serotonin-positive pericellular baskets. Substance P-, bombesin- and vasoactive intestinal polypeptide-like immunoreactive substances were found in the basal side of Merkel cells from sinus hair follicles of the cat, whereas the associated axons were immunonegative. In the principal trigeminal sensory nucleus, cell bodies and fibres, containing substance P and bombesin were observed in both subdivisions. In addition, only nerve fibres and terminals showed somatostatin-, cholecystokinin-, vasoactive intestinal polypeptide- and serotonin-like immunoreactivity. The present results provide direct evidence that an ascending peptidergic system exist and that only substance P and, less likely, bombesin may be primary afferent neuroregulator(s) for the mechanosensory information in the cat trigeminal system.

Afferent Pathways↗
PubMed1994

Primary trigeminal afferent neuron of the cat: I. Studies on membrane-bound enzyme histochemistry.

The localization of some membrane-associated enzymes such as alkaline phosphatase, 5'-nucleotidase, glucose-6-phosphatase, Na+,K(+)-adenosine triphosphatase, adenylate cyclase and guanylate cyclase in the Merkel cell-axon complexes, trigeminal ganglia and the principal trigeminal sensory nucleus of the cat was determined at light and electron microscopic level using cytochemical techniques. In the sinus hair follicles (vibrissae), the reaction end product marking alkaline phosphatase and adenosine triphosphatase activities was visualized on the axons running through external follicle epithelium and the 5'-nucleotidase, adenylate- and guanylate cyclase positive reaction was seen to stain the plasma membranes of Merkel cells. In the trigeminal ganglia, the strongest alkaline phosphatase and adenosine triphosphatase activities showed the corresponding areas between the ganglion and satellite cells. 5'-nucleotidase activity was more intense on the neurilemmas and the surrounding glial plasma membranes. In the principle sensory trigeminal nucleus, the central neurons exhibited an intense alkaline phosphatase, 5'-nucleotidase and adenosine triphosphatase activities and much smaller amount of reaction product for adenylate cyclase and guanylate cyclase was observed. In conclusion, membrane-bound enzymes could be histo- and cytochemically demonstrated in all components of primary trigeminal afferent units. Our results have confirmed that the receptor function and the nerve impulses conductance need an intensive molecular and cation exchange, and energy supply.

5'-Nucleotidase↗
PubMed1990

Cytochemical localization of 5'-nucleotidase activity in the nodose ganglion of the rabbit.

5'-nucleotidase (5'N) activity was histochemically examined in the rabbit nodose ganglion at light and electron microscopic levels. Under the light microscope, the 5'N activity was clearly demonstrated on the satellite cells and their processes surrounding neurons. No deposits of reaction product were observed within the perikarya of the ganglion cells and at intracellular sites in the glial cells. Electron microscopically, the reaction product of enzyme activity was located in both neuronal and satellite cell membranes, usually on the external surface. The glial cells exhibit the enzyme activity more extensively than the neurons. The presence of membrane-bound 5'N activity on the external aspect of the plasma membranes supports earlier findings that the functional role of the enzyme in the primary sensory neurons is related to processes of intracellular communication.

5'-Nucleotidase↗
PubMed1990

Localization of somatostatin-like immunoreactive fibres in the trigeminal principal sensory nucleus of the cat.

The location and distribution of nerve fibres and terminals displaying somatostatin-(SOM)-like immunoreactivity (LI) has been examined in cat trigeminal principal sensory nucleus (Vp) using the peroxidase-antiperoxidase technique. The varicose SOM-LI nerve fibres form a fine network in the Vp. SOM-positive terminals are distributed throughout Vp but they are particularly abundant in the ventral subdivision of the nucleus (Vpv). The labelled terminals make predominantly asymmetric axodendritic synaptic contacts. SOM-LI terminals only rarely form symmetrical synapses with non-reactive neuronal elements and are also present free in the neuropil. No SOM-LI perikarya are detected in the Vp. The results of the present study suggest that the majority, if not all, of SOM-LI fibres in the Vp are probably of primary afferent origin and may be involved in relaying trigeminal sensation to neuron located in this brain area.

Animals↗