PubMed Health⌕ Search

Biomedical subjects

I S Persina

Publications and source records attributed to I S Persina.

At least 19 recordsLinked to original sources
PubMed1992

Age-related loss of axospinous synapses formed by two afferent systems in the rat dentate gyrus as revealed by the unbiased stereological dissector technique.

Previous attempts to elucidate whether a loss of hippocampal synapses occurs during aging provided conflicting results, possibly due to the unavailability, at the time, of unbiased methods for synapse quantitation. This study was designed to reexamine the issue by means of modern technical procedures that provide unbiased estimates of synaptic numbers. Groups of 14 young adult (5 months old) and 14 aged (28 months old) male Fischer-344 rats were compared. Synapses were examined in the middle (MML) and inner (IML) molecular layer of the hippocampal dentate gyrus, where synaptic contacts are predominantly formed by different systems of afferents, the entorhinal and commissural-associational fibers, respectively. The number of synapses per neuron was estimated with the aid of the stereological dissector technique. The results showed that the total number of synaptic contacts per neuron was significantly diminished in the MML (by 23.6%) and IML (by 22.7%) of aged rats relative to young adults. This age-related synaptic loss involved axospinous, but not axodendritic, junctions of the MML (-24.4%) and IML (-24.0%). Both perforated and nonperforated axospinous synapses (distinguished by a discontinuous or continuous postsynaptic density, respectively) exhibited an age-dependent decrease in numbers, though this decrease did not reach statistical significance in the case of perforated junctions of the IML. The observed age-related loss of axospinous synapses may underlie the reduction in the amplitude of excitatory postsynaptic potentials and the decline in functional synaptic plasticity detected in the dentate gyrus of senescent rats.

Afferent Pathways↗
PubMed1992

Structural synaptic plasticity associated with the induction of long-term potentiation is preserved in the dentate gyrus of aged rats.

Changes in synaptic numbers were examined in the hippocampal dentate gyrus of aged (28 months old) rats following the induction of long-term potentiation (LTP) by high-frequency stimulation of the medial perforant path carried out on each of 4 consecutive days. Potentiated animals were sacrificed 1 hour after the fourth stimulation. Stimulated but not potentiated and implanted but not stimulated rats of the same chronological age served as controls. Synapses were analyzed in the middle (MML) and inner (IML) molecular layer of the dentate gyrus. Using the stereological dissector technique, unbiased estimates of the number per neuron were obtained for the following morphological varieties of synapses: axodendritic synaptic junctions involving dendritic shafts, nonperforated axospinous synapses having a continuous postsynaptic density (PSD), and perforated ones distinguished by a fenestrated, horseshoe-shaped, or segmented PSD. The induction of LTP resulted in a selective increase in the number of synapses with segmented PSDs. This change was detected only in the potentiated synaptic field (MML), but not in an immediately adjacent one (IML), which was not directly stimulated during the induction of LTP. Comparison of these data with the results of our previous LTP study in young adult rats (Geinisman, Y. et al., 1991, Brain Res. 566:77-88) showed that the only significant difference in the absolute number of synaptic contacts per neuron between potentiated animals of the two chronological ages was an age-related reduction in segmented synapses of the MML. Relative increases in the number of segmented synapses per neuron were, however, virtually of the same magnitude in potentiated rats of both ages as compared with their respective controls. This finding may explain why senescent rats can be potentiated to the same extent as young ones.

Acoustic Stimulation↗
PubMed1991

[A comparative study of the quantitative distribution and ultrastructure of Langerhans cells in the epidermis of patients with chronic benign dermatoses and mycosis fungoides].

Using histoenzymatic assay for ATPase activity and electron microscopy, Langerhans' cells (LC) in biopsy specimens taken from skin lesions of 20 patients with chronic benign dermatoses (CBD) and of 28 patients suffering from mycosis fungoides (MF) were identified. In the early lesions of MF the reduction of the number of cell dendrites, disappearance of normal arrangement and the reduced absolute quantity of LC were observed on comparison with patients with CBD. Ultrastructurally, the destroyed forms of LC were predominantly observed in MF lesions, while in cases of CBD most of the LC were functionally active. The authors suggest that the examination of functional activity, quantitative distribution and ultrastructural features of LC should be used as an early morphologic test for differential diagnosis of early signs of MF and CBD this being of vital importance for an adequate and due treatment.

Adenosine Triphosphatases↗
PubMed1990

[Malignant lymphomas of the skin (clinico-morphological parallels)].

On the basis of clinico-morphological analysis of 104 patients with malignant skin lymphomas (MSL) they are subdivided into two groups: epidermotropic (mycosis fungoides, prolymphocytic and lymphoblastic MSL with sinuous nuclei, histiocytic MSL) and non-epidermotropic (prolymphocytic MSL with roundish nuclei, microlymphoblastic and immunoblastic MSL). The former group differs from the latter by the involvement of the epidermis, with hyperplasia of keratinocytes and the disturbance of their differentiation, penetration of tumour cell into the epidermis and by the composition, type and localization of the proliferate. Epidermotropic MSL were much more frequent, affected younger persons, had a longer duration, more widespread skin involvement with polymorphic eruptions. Non-epidermotropic MSL were characterised by the appearance of single tumours of the skin and early generalization.

Autoradiography↗
PubMed1989

[Disordered keratinocyte differentiation in epidermal tumors and mycosis fungoides].

The immunocytochemical method with monoclonal antibodies to human and murine epidermis basal-cell antigen (BCAg) has been used in studies on the disorders in keratinocyte differentiation in epidermal tumors and mycosis fungoides. The fluorescence intensity augmented and BCAg distribution in the cytoplasm grew more diffuse as the degree of the tumor cell differentiation lowered. In mycosis fungoides the BCAg reaction has been positive first in the suprabasal layers; as the disease progressed, the fluorescence has involved the entire epidermis. The BCAg test is a sensitive tool for estimating the epidermal cell maturity in processes associated with impaired differentiation of keratinocytes.

Antibodies, Monoclonal↗
PubMed1989

[Complex assessment of the proliferation of epidermal and tumor cells in malignant skin lymphoma].

Keratinocyte and tumor cell proliferative activities in skin biopsy specimens of 49 patients with various forms of malignant lymphomas of the skin are analyzed. The mitotic index and 3H thymidine labeled nuclei index in the epidermal and tumor proliferate cells were under study; cytophotometry of the tumor cell DNA was carried out, as well as analysis of correlations of the examined parameters and the patients' life spans. The findings evidence an increase of the keratinocyte proliferative activity in epidermotropic malignant lymphomas of the skin, this pointing to the significance of epidermal abnormalities in the development of this condition.

Adult↗
PubMed1989

[Sweet's syndrome].

A patient aged 50 with Sweet's syndrome combined with renal diseases is described. The clinical and pathomophological picture of the disease is described in detail. The skin process regressed after left percutaneous nephrostomy performed for the left ureter obstruction and after antibiotic and depuration therapy.

Biopsy↗
PubMed1989

[The clinical characteristics of malignant lymphomas of the skin].

Analyzing the morphologic changes in 106 biopsy specimens from patients with malignant lymphomas of the skin (MLS), the authors paid special attention to abnormalities in the epidermis and to specific features of the infiltrate. Correlations between MLS morphologic types and clinical symptoms were followed. Despite a variety of clinical symptoms of MLS, specific features of each morphologic form and group (of epidermotropic and nonepidermotropic lymphomas) were detected. Since MLS diagnosis should be based on the clinical and morphologic data, the knowledge of the clinical picture corresponding to every morphologic variety of MLS will help the dermatologist predict the disease course and define the examination and treatment strategy for this patient population.

Adult↗
PubMed1989

[The significance of epidermal changes in the early diagnosis and development of mycosis fungoides].

In 47 patients with stage I mycosis fungoides, biopsy of skin has revealed substantial changes in epidermis acanthosis with confluent epidermal processes, focal dystrophy of basal cells, mitoses in various epidermal layers, parakeratotic foci without a granular layer. Histoautoradiographic and immunomorphological studies demonstrated that enhanced proliferative activity of keratinocytes that was more pronounced in stages I and II mycosis fungoides and impaired epidermal differentiation that was predominant in neoplastic stage III underlay the above changes. There was ultrastructural evidence for abnormal epidermal keratinization. It was proposed that epidermal abnormalities made an important contribution to the development of mycosis fungoides.

Fluorescent Antibody Technique↗
PubMed1987

[Angiolymphoid hyperplasia with eosinophilia (Kimura disease)].

Angiolymphoid hyperplasia with eosinophilia (ALHE) is characterized by the appearance of tumour-like nodes on skin and subcutaneous fat. Vascular proliferation with inflammatory infiltration consisting of lymphocytes and eosinophiles, as well as structures of lymphoid follicle type were revealed microscopically. A description is given of a patient, 34 yr. old, with typical clinical and morphological manifestations of ALHE. Basing on the literature and on the own experience the authors suggest that ALHE and Kimura disease are variants of one nosologic form.

Adult↗
PubMed1987

[Morphology of mastocytosis].

Histochemical and electron-microscopic studies of skin biopsy specimens from 65 patients with mastocytosis have enabled the authors to classify the various mastocytoses (on the basis of infiltrate topography and structural features of mast cells) into macular, pustular, and nodular varieties of cutaneous mastocytosis (urticaria pigmentosa) and mastocytoma. No differences in mast cell structure were detected between cutaneous and systemic mastocytoses. Electron microscopically, mast cells in both appeared normal, with a predominance of granules having a fine-grained or homogeneous matrix and a small number of lamellar structures. In mastocytomas, on the other hand, ultrastructural changes and considerable degranulation were observed in the mast cells.

Adolescent↗