A M Paloff

Medical University of Sofia, Ulpia Serdica, Sofia-Capital, Bulgaria

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Publications (47)31.27 Total impact

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    ABSTRACT: An intriguing case of multiple muscular variations in an adult male cadaver was observed during routine anatomical dissection. On external body examination there was a low degree of kyphoscoliosis but no other visible signs of dysmorphic features were detected. The following dissection however revealed the presence of many aberrant muscles in the neck and upper chest including pectoralis quartus, axillary arch muscle, supraclavicularis proprius, additional aberrant sternohyoideus, hyoclavicularis and levator claviculae. Most of the aforementioned variant muscles are known from literature descriptions as rare isolated findings, but the presence of so many anomalous structures in one and the same body are an evidence for a congenital profound disturbance in the embryonic development of the neck and upper chest muscles. Key words: muscular variations, anomalous muscles, development
    Folia medica, vol. 57, suppl. 2, pp. 37-38; 06/2015
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    ABSTRACT: There is considerable evidence describing the commonality of opioid and cannabinoid receptor systems. Opioid peptides are widely known as modulators of numerous CNS functions, in particular, nociception. In addition to abundant extant literature on this topic, data from our previous investigations show that the short-chain neuropeptide and neuromodulator kyotorphin (KTP) binds to a specific receptor and plays a role in pain regulation, thermoregulation and exploratory behavior (Dzhambazova and Bocheva, J. Biomed. Clin. Res., 2010, 3:3-11; Dzhambazova et al., Amino Acids, 2011, 4:937-944). According to several studies, the action of KTP on integrative brain functions in animals is not blocked by the pure opioid antagonist naloxone. This fact has led to much investigation of its interaction with monoaminergic systems. However, to our knowledge, the interaction between KTP and cannabinoid systems has yet to be studied. The aim of the present study was to investigate the effect of KTP on the
    Neuroscience 2014, Washington DC, USA; 11/2014
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    ABSTRACT: Using the NADPH-diaphorase histochemical technique, we investigated the morphology and topographical distribution of labeled neurons and fibers in the human inferior colliculus. NADPHd-positive neurons were distributed throughout its three major divisions: the central nucleus, the lateral nucleus and the pericentral nucleus. Relative to the other two divisions, large numbers of positive neurons were observed within the ventromedial aspect of the central nucleus. Taking into account the size and shape of labeled perikarya as well as their dendritic and axonal characteristics, neurons were categorized by diameter into three types: large, medium and small. Large neurons ranged from 30-45.5µm in diameter, their perikarya representing a variety of shapes including elliptical, irregular, fusiform and multipolar. Medium neurons varied from 25-30µm in diameter, most often seen with multipolar, bipolar or irregular cell bodies. Small neurons ranged from 13-18µm in diameter and were
    Neuroscience 2014, Washington, DC, USA; 11/2014
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    ABSTRACT: The morphology and distribution of parvalbumin-immunoreactive neurons (PV-ir) were studied in the human claustrum. PV-ir neurons were observed throughout the claustrum, with the highest numbers noted in the central (broadest) portion as compared with the dorsal and ventral aspects. Reaction product was evident in the neuronal perikarya, dendritic processes, and spines. In the majority of these labeled neurons, the cytoplasm was devoid of lipofuscin pigment. Cell bodies varied widely in both shape and size, ranging from oval and small, to multipolar and large. PV-ir neurons were classified into two groups, primarily based on dendritic morphology: spiny neurons with long and straight dendrites, and aspiny neurons with thin and curving dendritic processes. PV-ir fibers were seen throughout the neuropil, with many immuno-positive puncta noted.
    Brain Structure and Function 09/2014; 219(5):1813-30. DOI:10.1007/s00429-013-0603-x · 4.57 Impact Factor
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    ABSTRACT: The claustrum is a telencephalic nucleus located ventrolateral to the basal ganglia in the mammalian brain. It has extensive reciprocal connectivity with most if not all of the cerebral cortex, in particular, primary sensory areas. However, despite renewed and growing interest amongst investigators, there remains a paucity of data concerning its peptidergic profile. The aim of the present study was to examine the presence, morphology, distribution and ultrastructure of neuropeptide Y-immunoreactive (NPY-ir) neurons and fibers in the claustrum of the cat. Ten adult healthy cats from both sexes were used. All animals received humane and ethical treatment in accordance with the Principles of Laboratory Animal Care. Subjects were irreversibly anesthetized and transcardially perfused with fixative solution containing glutaraldehyde and paraformaldehyde. Brains were promptly removed, postfixed and sectioned. Slices were incubated with polyclonal anti-NPY antibodies according to the standard Avidin-Biotin-Peroxidase Complex method adopted by our Department of Anatomy, Histology and Embryology. NPY-ir neurons and fibers were found to be diffusely distributed throughout the claustrum, with no obvious topographic or functional patterning other than larger numbers in its central/broadest part (stereotaxic planes A12-A16). Neurons were generally classified by diameter into three sizes: small (under 17μm), medium (17-25μm) and large (over 25μm). Staining density varied, with some neurons appearing darker than others. At the electron-microscopic level NPY immunoproduct was observed within neurons, dendrites and terminal boutons, each differing relative to their ultrastructural attributes. Two types of NPY-ir synaptic boutons were found. Lastly, it is of interest to note that gender-specific differences were not observed.
    Journal of Chemical Neuroanatomy 08/2014; 61-62. DOI:10.1016/j.jchemneu.2014.08.007 · 2.52 Impact Factor
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    ABSTRACT: We studied the topographical distribution and morphological characteristics of NADPH-diaphorase-positive neurons and fibers in the human claustrum. These neurons were seen to be heterogeneously distributed throughout the claustrum. Taking into account the size and shape of stained perikarya as well as dendritic and axonal characteristics, Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd)-positive neurons were categorized by diameter into three types: large, medium and small. Large neurons ranged from 25 to 35 μm in diameter and typically displayed elliptical or multipolar cell bodies. Medium neurons ranged from 20 to 25 μm in diameter and displayed multipolar, bipolar and irregular cell bodies. Small neurons ranged from 14 to 20 μm in diameter and most often displayed oval or elliptical cell bodies. Based on dendritic characteristics, these neurons were divided into spiny and aspiny subtypes. Our findings reveal two populations of NADPHd-positive neurons in the human claustrum-one comprised of large and medium cells consistent with a projection neuron phenotype, the other represented by small cells resembling the interneuron phenotype as defined by previous Golgi impregnation studies.
    Frontiers in Systems Neuroscience 05/2014; 8:96. DOI:10.3389/fnsys.2014.00096
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    ABSTRACT: ABSTRACT Leucine-enkephalin is a potent and naturally-occurring opioid peptide which serves to inhibit other neurotrans- mitters involved with pain perception, thereby reducing its emotional and physical impact. Nevertheless, there is little data in the literature concerning leucine-enkephalin-immunoreactivity (Leu-enk-ir) in the human claus- trum. The objectives of this study were to confirm the existence of leucine-enkephalin immunoreactive neurons and fibers in the human claustrum. Light microscopy was used to describe their morphology and distribution. Samples of claustrum were obtained from the brains of two females (39 and 48 years of age) and two males (27 and 42 years of age). The brains did not show any overt signs of pathology or trauma. Immunoreactivity to Leu- enk was assessed via the Avidin-Biotin Complex Method. Light-microscopic analysis confirmed the presence of Leu-enk-ir neurons and fibres in all areas of the human claustrum. The cell bodies varied in shape and size, and were divided into three groups: small, medium and large. The density of immunostaining varied both within and between the cell types, with some neurons, staining more darkly or lightly than others. The large and medium sized cells most likely correspond to claustrocortical pro- jection neurons while the small-sized cells appear to be inhibitory interneurons. It is our hope that these results will be contributed to a better understanding the functions of claustrum, in both health and disease, given its relationship with the development of autism, schizophrenia, Alzheimer disease, Parkinson disease and Hun- tington disease. Key words: leucine-enkephalin, human claustrum, immunocytochemistry
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    ABSTRACT: The prefrontal cortex (PFC), which mediates the emotional coping response to different stress- ful paradigms, is composed of distinct parts depends on stimulus involved physical or psycho- logical stress. It also plays a role in a number of neurological conditions. It’s known that neuro- endocrine control of homeostatic and reproductive functions including stress response and en- ergy metabolism is fulfils by important signaling molecules as endogenous cannabinoids. The aim of the present study was to examine the effects of cold stress on distribution of CB1- receptors in PFC of rats. Immunohistochemical procedure for CB1-receptors was performed in adult male Wistar rats. The data were entered in the computer program, recorded automatically, calculated and compared by Student’s t-test. We found CB1-immunoreaction in axons and dendrites as well as in cell bodies where they presented as puncta on somata. The cells bodies were comprised of several distinct shapes: pyramidal, oval, fusiform and multipolar. Numerous fine-beaded fibers and puncta were seen on a handful of pyramidal large-sized neurons and many puncta were observed around the oval-shaped small- and medium-sized neurons.The PFC in cold stress rats demonstrated around 18% higher density of CB1-receptors compared with controls. In conclusion our results showed that cold stress exposure increased distribution of CB1-receptors in PFC of rats. These experimental data suggest that endocannabinoid system in this brain area may play an impor- tant role in the continuity of homeostasis in cold stress. Key words: CB1-immunoreactive neurons, cold stress, prefrontal cortex, rats
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    ABSTRACT: Cannabinoids and opioids interact in a number of ways that could be therapeutically beneficial. The CB1 re- ceptors are implicated with the endocannabinoid-mediated modulation of stress, pain, visceral sensation, synaptic plasticity in the thalamus via GABAergic signaling. Thalamic reticular nucleus (TRN) is a thin sheet of GABAergic neurons surrounding anterolateral surface of the thalamus. In our immunohistochem- ical study we demonstrated expression of CB1 immunoreactive neurons in a light microscope during a nor- mal condition and after the acute stress in the rats. We found higher expression of CB 1 immunoreactivity in stressed animals compared with control group. Opioids and cannabinoids have been shown to have analgesic properties and they are considered as drug tar- gets for the treatment of numerous neurological disorders, pain and stress. Key words: Thalamic reticular nucleus, CB 1 receptors, immobilization stress, rat
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    ABSTRACT: The synaptic proteins synaptobrevin/VAMP, SNAP-25, Syntaxin1, NSF and α-SNAP were revealed by means of immunocytochemistry. Materials from the cerebral cortex of adult, newborn and postnatal rats (P6 and P11) were used. Immunostaining for synaptobrevin/VAMP was mainly around the synaptic vesicles, whereas the immunolabeling for SNAP-25 and syntaxin1 was revealed in most cases on the cytoplasmic surface of the presynaptic membrane and to a lesser extend - on synaptic vesicles. Immunostaning for NSF and α-SNAP was found out not only on the axoplasm of axonal endings and varicosities, but also in perikarya and dendrites. In the cerebral cortex of newborn rats, a small number of immunopositive presynaptic parts could be observed. The number of these immunolabeled structures increases evidently with increasing age of rats.
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    ABSTRACT: The claustrum is a complex telencephalic structure owing to its reciprocal connectivity with most-if not all-cortical areas. However, there is a paucity of data in the literature concerning its histochemical components, including opioid peptide neurotransmitters. The aim of the present study was to examine the morphology, distribution and ultrastructure of leucine-enkephalin-immunoreactive (Leu-enk-ir) neurons and fibers in the dorsal claustrum (DC) of the cat. Seven healthy, adult male and female cats were used in our study. All animals received humane care. They were irreversibly anesthetized and transcardially perfused with fixative. Brains were removed, postfixed, blocked and sectioned. Sections were incubated with polyclonal anti-Leu-enk antibodies using the Avidin-Biotin-Peroxidase Complex method. Leu-enk-ir neurons and fibers were distributed throughout the DC. Some of the neurons were lightly-stained, while others were darkly-stained. Light-microscopically, they varied in shape: oval, fusiform, multipolar and irregular. With regard to size, they were categorized as small (15 μm or less in diameter), medium (16-20 μm in diameter) and large (21 μm or more in diameter). No specific pattern of regional distribution was found. On the electron microscope level, immunoproduct was observed in neurons, dendrites and terminal boutons. Different types of Leu-enk-ir neurons differ in their ultrastructural features, including two types of synaptic boutons. No gender-specific features were observed. In conclusion, it is our hope that our study will serve to contribute to a better understanding of the functional neuroanatomy of the DC in the cat, and that it can be extrapolated and applied to other mammals, including humans.
    Journal of molecular histology 09/2012; DOI:10.1007/s10735-012-9448-5 · 1.98 Impact Factor
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    ABSTRACT: D uring routine anatom ical dissection o f the left anterior forearm o f an elderly fem ale cadaver, tw o sepa­ rate m uscles having characteristics o f palm aris longus have been observed. The lateral o f the m uscles had a typical palm aris longus com position - sm all proxim al m uscular belly and a long distal tendon continuing into the palm ar aponeurosis. The second, m edial m uscle started w ith a thick tendon from the m edial epicondyle o f the hum erus. Its m uscular belly occupied the m iddle third o f the forearm ; in the low er third it turned into a short, broad tendon attached to the flexor retinaculum and to the proxim al attachm ent sites o f the thenar and hypothenar m uscles. The clinical im portance o f this variation is due to the close relations o f the distal tendons w ith the neurovascular structures in the anterior wrist. K ey words: palm aris longus, variation, clinical significance, entrapm ent
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    ABSTRACT: Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. Nevertheless there are little data about the neuronal Nitric Oxide Synthase immunoreactive (nNOS-ir) neurons and fibers in the dorsal claustrum (DC) of a cat. In this respect the aims of this study were: (1) to demonstrate nNOS-ir in the neurons and fibers of the DC; (2) to describe their light microscopic morphology and distribution; (3) to investigate and analyze the ultrastructure of the nNOS-ir neurons, fibers and synaptic terminals; (4) to verify whether the nNOS-ir neurons consist a specific subpopulation of claustral neurons; (5) to verify whether the nNOS-ir neurons have a specific pattern of organization throughout the DC. For demonstration of the nNOS-ir the Avidin-Biotin-Peroxidase Complex method was applied. Immunopositive for nNOS neurons and fibers were present in all parts of DC. On the light microscope level nNOS-ir neurons were different in shape and size. According to the latter they were divided into three groups-small (with diameter under 15 microm), medium-sized (with diameter from 16 to 20 microm) and large (with diameter over 21 microm). Some of nNOS-ir neurons were lightly-stained while others were darkly-stained. On the electron microscope level the immunoproduct was observed in neurons, dendrites and terminal boutons. Different types of nNOS-ir neurons differ according to their ultrastructural features. Three types of nNOS-ir synaptic boutons were found. As a conclusion we hope that the present study will contribute to a better understanding of the functioning of the DC in cat and that some of the data presented could be extrapolated to other mammals, including human.
    Journal of Molecular Histology 09/2008; 39(4):447-57. DOI:10.1007/s10735-008-9184-z · 1.98 Impact Factor
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    ABSTRACT: During unilateral selective cerebral perfusion (SCP), via cannulation of the brachiocephalic trunk, the brain receives blood only through the right common carotid artery and the right vertebral artery. For perfusion of the contralateral (left) hemisphere it is counted on the competence of the circle of Willis (CoW). It is well known that variations of CoW are present in more than 50% of the people. Furthermore, these variations usually affect more than one vessel of the circle. The aim of the present work was to study the variations of CoW, which could have an impact on cerebral blood supply during unilateral SCP. We study 112 CoWs obtained from cadavers via routine dissection in the Department of Forensic Medicine of Medical University, Sofia. The external diameter of both vertebral arteries and all arteries that form CoW was measured with a caliper-gauge. We identify the variations of CoW such as significant hypoplasy and/or lack of a branch of the circle. Bearing in mind the characteristics of the blood flow during unilateral SCP some of these variations were classified as significant during unilateral SCP. They were subdivided into groups according to most probable stroke site after unilateral SCP. Because of the high percent of the variations, hemodynamically significant during unilateral SCP, a suggestion for routine preoperative CT-angio of CoW could be made. Furthermore, an intraoperative follow-up with NIRO, transcranial Doppler, EEG, and so forth could also be recommended.
    European Journal of Cardio-Thoracic Surgery 07/2007; 31(6):982-9. DOI:10.1016/j.ejcts.2007.03.020 · 2.81 Impact Factor
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    ABSTRACT: The presence of the calcium-binding protein (CaBP) parvalbumin (PV) in the neuronal elements of the cat's dorsal claustrum was studied by immunohistochemistry at the light- and electron-microscopic level. PV-immunoreactive neurons and fibers were detected in all parts of the claustrum. The PV-immunoreactive neurons were divided into several subtypes according to their size and shape. Approximately 7% of all PV-immunoreactive neurons were classified as large, while approximately half of the labeled neurons were medium-sized. The small PV-immunoreactive neurons were 45% of the total PV-immunoreactive neuronal population. Ultrastructurally, many spiny and aspiny dendrites were heavily immunolabeled, and the reaction product was present in dendritic spines as well. Several types of synaptic boutons containing reaction product were also found. These boutons terminated on both labeled and unlabeled postsynaptic targets (soma, dendrites, etc.), forming asymmetric or symmetric synapses. Approximately 70% of all PV-immunoreactive terminals contained round synaptic vesicles and formed asymmetric synapses. The majority of these boutons were of the ''large round'' type. A lesser percentage were of the ''small round'' type. This paper represents the first study demonstrating the existence of PV, a CaBP, in the cat claustrum, and its distribution at the light and electron microscope level. Beyond the relevance of this research from the standpoint of adding to the paucity of literature on PV immunoreactivity in the claustrum of various other mammals (e.g. monkey, rabbit, rat, mouse), it is of particular significance that the cat claustrum is more similar to the rabbit claustrum than to any other mammalian species studied thus far, noted by the existence of four distinct morphologic subtypes. We also demonstrate a lack of intrinsic, and possibly functional, heterogeneity as evidenced by the uniform distribution of PV throughout the cat claustrum, across the four cell subtypes (i.e. inhibitory interneurons as well as projection neurons). Indeed, the association with, and influence of, the cat claustrum on diverse multisensory mechanisms may have more to do with its afferent than efferent relationships, which speaks strongly for its importance in the sensory hierarchy. Exactly what role PV plays in the claustrum is subject to discussion, but it can be postulated that, since CaBP is associated with GABAergic interneurons, synaptogenesis and neuronal maturation, it may also serve as a neuroprotectant, particularly with regard to pathologies associated with the aging process, such as in Alzheimer's disease.
    Acta Histochemica 02/2007; 109(1):61-77. DOI:10.1016/j.acthis.2006.09.006 · 1.76 Impact Factor
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    ABSTRACT: Nitric oxide is a unique neurotransmitter, which participates in many physiological and pathological processes in the organism. Nevertheless, there are little data about the neuronal nitric oxide synthase immunoreactivity (nNOS-ir) in the vestibular complex of a cat. In this respect, the aims of this study were to: (1) demonstrate nNOS-ir in the neurons and fibers, from all major and accessory vestibular nuclei; (2) describe their light microscopic morphology and distribution; (3) investigate and analyze the ultrastructure of the NOS I-immunopositive neurons, fibers, and synaptic boutons. For demonstration of the nNOS-ir, the peroxidase-antiperoxidase-diaminobenzidin method was applied. Immunopositive for nNOS neurons and fibers were present in all major and accessory vestibular nuclei. On the light microscope level, the immunopositive neurons were different in shape and size. According to the latter, they were divided into four groups--small (with diameter less than 15 microm), medium-sized (with diameter from 15 to 30 microm), large type I (with diameter from 30 to 40 microm), and large type II (with diameter greater than 40 microm). On the electron microscope level, the immunoproduct was observed in neurons, dendrites, and terminal boutons. According to the ultrastructural features, the neurons were divided into three groups--small (with diameter less than 15 microm), medium-sized (with diameter from 15 to 30 microm), and large (with diameter greater than 30 microm). At least two types of nNOS-ir synaptic boutons were easily distinguished. As a conclusion, we hope that this study will contribute to a better understanding of the functioning of the vestibular complex in cat and that some of the data presented could be extrapolated to other mammals, including human.
    Journal of Molecular Histology 12/2006; 37(8-9):343-52. DOI:10.1007/s10735-006-9061-6 · 1.98 Impact Factor
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    ABSTRACT: Abstract HIV-1 attacks directly CNS in AIDS patients. Among 52 mortal cases with AIDS the brains of 48 are studied by light microscopy. They reveal brain cortex atrophy, perivascular mononuclear cell infiltrates and signs of neuronophagy. Corresponding ultrastructural findings in 8 cases proved to be macrophages or histiocytes. Viral particles are identified in their surface and exstracellular space. The virions measuring 100-120 nm in diameter exhibit circular envelopes transected by inner lucid cores. Subplasmalemmal linear densities are prominent featuring the virus-associated cells.
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Publication Stats

187 Citations
31.27 Total Impact Points

Institutions

  • 2005–2014
    • Medical University of Sofia
      • Department of Anatomy and Histology
      Ulpia Serdica, Sofia-Capital, Bulgaria
  • 2004
    • University Children's Hospital Sofia Bulgaria
      Ulpia Serdica, Sofia-Capital, Bulgaria