Biomedical subjects

S Baloyannis

Publications and source records attributed to S Baloyannis.

7 recordsLinked to original sources

PubMed1991

Ultrastructural changes of stapedius muscle and stapedius branch nerve endings in otosclerotic patients.

We studied in the electron microscope 12 stapedius muscles and stapedius branches of the facial nerve excised from otosclerotic patients who underwent stapedectomy for hearing restoration. Almost all of the stapedius, muscles demonstrated morphological alterations, such as accumulation of lipids and osmiophilic material, dilatation of the sarcoplasmic reticulum, sarcoplasmic invaginations of the nuclei and accumulation of fibroblasts and satellite cells on the surface of the muscle fibers. The stapedius branch of the facial nerve demonstrated a marked loss of myelinated fibers. Most of the unmyelinated or demyelinated fibers were surrounded by thick processes of the Schwann cell. The axons showed a paucity of neurofilaments and the nerve endings showed a rough dilatation of the cisternae of the smooth endoplasmic reticulum as well as accumulation of osmiophilic material. The morphological alterations of the stapedius muscle and the stapedius branch of the facial nerve in otosclerosis suggest that in addition to the lesions of the bone at various areas of predilaction, a substantial pathological alteration of the muscle and nerve fibers also occurs in the middle ear adjacent or distal to otosclerotic foci, a fact that enlarges the concept of the pathological spectrum of the disease.

Facial Nerve↗

PubMed1981

Histological and ultrastructural findings in the vocal muscles of patients suffering from muscular dystrophies.

Biopsy material from the vocal muscle of patients suffering from Steinert's muscular dystrophy, Duchenne's muscular dystrophy, oculopharyngeal progressive muscular dystrophy, and paraneoplastic myopathy was examined under the light and electron microscope. The histological findings were compatible with the muscular changes seen in the skeletal muscles of the extremities of the same patients. Slight differences in the severity of the pathologic process were noticed in correlation with the muscles of the extremities which were always more seriously affected than the vocal muscles. The ultrastructural study revealed a moderate to very permanent dilatation of the sarcotubular system, involving the T-tubules and the cisternae of the smooth endoplasmic reticulum as well. From the clinical point of view, the vocal muscle biopsy was beneficial to the patients suffering from Steinert's myotonic muscular dystrophy, whereas it did not affect the clinical condition of the others.

Biopsy↗

PubMed1981

The fine structure of the isomorphic oligodendroglioma.

The fine structure of 26 isomorphic oligodendrogliomas excised from various areas of the Central Nervous System is described. These tumors are composed mainly of three types of cells: (a) those with large round or ovoid nuclei and scanty cytoplasm, (b) those with abundant cytoplasm, very rich in organelles and (c) cells very fibrillated with long cellular processes. The cytoplasm of the second cell type sometimes included crystalline bodies, numerous microtubules, myelin-like membranous structures and a large number of elongated mitochondria. The cells with the very fibrillated cytoplasm are eigher astrocytes intermixed with the neoplastic cells of the oligodendrocytic line or an astrocytic-like cellular evolution of the immature neoplastic cell of the oligodendrocytic line. Ultrastructural analysis provided evidence that isomorphic oligodendroglioma is not as homogeneous as was considered to be at the light microscopy level.

Brain Neoplasms↗

PubMedDate not supplied

A pilot, open label, clinical trial using hydroxyzine in multiple sclerosis.

Multiple sclerosis (MS) is an autoimmune disorder of myelin destruction. Blood-brain-barrier (BBB) disruption precedes pathological or clinical findings and could involve mediators from perivascular brain mast cells, such as histamine and vascular endothelial growth factor (VEGF). Mast cells could be activated by many triggers, including acute stress that has been correlated with MS exacerbations. We considered that the histamine-1 (H1) receptor antagonist hydroxyzine, which also partially inhibits brain mast cells and has anxiolytic properties, may reduce MS symptoms. This open label, pilot, clinical trial investigated the effect on MS of an oral solution of hydroxyzine (100 mg per day), together with caffeine (200 mg per day) to reduce sedation. Twenty patients (8 males; 12 females) with relapsing-remitting or relapsing-progressive MS completed the study (12 +/- 1 months) and were evaluated using disability scales. Most patients on hydroxyzine (75%) remained stable or improved neurologically and all but one showed improved mood. Hydroxyzine could be used as an adjuvant in MS, but the small number of patients enrolled and the short duration of the study precludes any definitive conclusions. A double-blind, placebo-controlled study is warranted.

Adolescent↗

PubMedDate not supplied

Substance P increases the polymorphism of the synaptic vesicles in the temporal isocortex cultured in vitro.

Rat's temporal cortex was cultured in vitro in a feeding medium enriched with substance P. Normal controls were used for correlation. The ultrastructural study of the explant exposed to substance P revealed a marked increase of the polymorphism of the synaptic vesicles in the presynaptic terminals. Large numbers of the synaptic vesicles were large, of a mean diameter of 142.5 A, dark-looking like the catecholaminergic vesicles. Coated vesicles were seen in the presynaptic terminals as well as in the postsynaptic ones. Large elongated vesicles and S-like vesicles were seen in the axonic terminals mainly in axosomatic synapses and in axodendritic synapses with large dendritic profiles. In most of the synapses, a remarkable thickness of the postsynaptic membrane was noticed. In a large number of postsynaptic terminals, the cisternae of the smooth endoplasmic reticulum were dilated and intermixed with dilated vesicles and fragmented microtubules. Some of the presynaptic terminals demonstrated marked thickness of the presynaptic membrane. Glycogen granules were frequently seen in the postsynaptic terminals. In conclusion, substance P administered in vitro, increases the polymorphism of the synaptic vesicles in the presynaptic terminals of neurons derived from the temporal isocortex.

Animals↗

PubMedDate not supplied

Substance P in the acoustic area of the cortex during neuronal development and maturation.

Substance P has been proved an important neurotransmitter and neuromodulator, serving not only as an excitatory transmitter of the first afferent synapse of pain pathways but as a valuable neuromodulator in the primary cortical areas of sensosensorial integration. In the human acoustic cortex, substance P has been found in the presynaptic terminals as well as in the cell bodies of numerous polyhedral, triangular and bipolar neurons. Using histochemical techniques, we found recently that substance P is first accumulated in the neuronal elements of the human acoustic cortex in 18-gestational-week (GW) fetuses. Most of substance P is distributed in the neurons of the 3rd and 4th cortical layers, mainly in the cell bodies, the initial part of the axons and the axonic terminals. In 24-GW fetuses, substance P is found in the 2nd cortical area inside the cell body of the granular and bipolar neurons. In 28-GW fetuses, substance P is found in the pre- and postsynaptic terminals. We would suggest that substance P is accumulated increasingly as a function of the neuronal maturity of the primary acoustic cortical area, serving mainly as a neuromodulator.

Auditory Cortex↗

PubMedDate not supplied

The neuropeptides in the acoustic cortex. I. Substance P.

Peptides are the most recently studied chemical category of neurotransmitters. Most of them are found located in special diencephalic neurons and in some cortical areas serving as transmitters for specific synaptic junctions. In the human acoustic cortex we tried to identify substance P which may participate in the synaptic transmission at the various morphological types of synapses.

Adult↗