Biomedical subjects

S Stanović

Publications and source records attributed to S Stanović.

6 recordsLinked to original sources

PubMed2000

Thiorphan, an inhibitor of neutral endopeptidase/enkephalinase (CD10/CALLA) enhances cell proliferation in bone marrow cultures of patients with acute leukemia in remission.

Thiorphan, (DL-mercapto-2-benzylpropanoyl)-glycine is a potent and specific inhibitor of membrane metallo-endopeptidase (EC 3.4.24.11, CD10). We explored its effects in short-term clonal cultures of the bone marrow from 10 patients with acute leukemia in remission. The cell suspensions were incubated with thiorphan (10(-13) to 10(-5) M) and seeded for the granulocyte/macrophage-colony forming unit (GM-CFU) assay. In normal bone marrow samples the median seeding efficiency was 119 colonies and clusters per 10(5) cells and thiorphan caused slight stimulation of the clonal growth in concentrations above 10(-9) M. In the leukemic samples, the median seeding efficiency varied from 10 to 366 colonies and clusters per 10(5) seeded cells. Meaningful alterations of the clonal growth were noted in 32 out of 83 thiorphan-treated cultures (39%). In those 32 cultures the stimulatory effects outnumbered the inhibitory effects (24 versus 8). Thus, thiorphan stimulated the progenitor cell proliferation in bone marrow samples from the normal donor and from the patients with acute leukemia in remission. Thiorphan binding to CD10 might interfere with the processing of neuropeptide hemoregulatory factors and thus influence the progenitor cell proliferation.

Acute Disease↗

PubMed1999

[Neuropeptides, endogenous opioid peptides and cell proliferation].

Neuropeptides are oligo- or polypeptidies having a number of common features including biosynthesis, metabolism and biological effectiveness at extremely low concentrations. They function as cotransmitters in the central, peripheral and autonomic nervous system. As autocrine, paracrine, neurocrine or endocrine factors, neuropeptides also directly modulate functions of many types of cells in different tissues, including the lymphoid tissue. Neuropeptides influence cell proliferation and differentiation. Those functions are accomplished by neuropeptide binding to specific receptors. Recent studies emphasize the participation of neuropeptides in the control of organogenesis in embryonal, fetal and early postnatal periods as well as in tumor growth control. The family of neuropeptides includes endogenous opioid peptides, found in nervous and many other tissues. Lymphoid and hematopoietic tissues produce opioid-like oligopeptides, and the membrane marker CD10/CALLA (enkephalinase) expressed on lymphoid, myeloid and stromal bone marrow cells functions as an enzyme processing the enkephalins and other neuropeptides. It might be assumed therefore that opioid peptides participate among other cytokines in the regulation of hematopoiesis.

Animals↗

PubMed1998

Thiorphan stimulates clonal growth of GM-CFU in short-term cultures of bone marrow from a healthy donor and from patients with non-Hodgkin lymphoma.

Thiorphan, a specific inhibitor of membrane neutral endopeptidase (NEP, EC 3.4.24.11) also known as the common acute lymphoblastic leukemia antigen (CALLA, CD10) was added into short-term clonal cultures of the buffy coat concentrates of human bone marrow obtained from a healthy donor (six experiments) and from ten patients with non-Hodgkin lymphoma (NHL) (eight in complete remission, one in partial remission and one in relapse). Thiorphan concentrations ranged from 10(-5) to 10(-13) M. Nanomolar and higher concentrations of the drug mildly stimulated the granulocyte-macrophage colony-forming unit (GM-CFU) counts in the cultures of normal bone marrow, reaching the significance at 10(-7) M. Meaningful alterations of the GM-CFU counts were noted in 31 of 79 thiorphan-treated cultures of NHL bone marrow (39%). In those cultures the stimulatory effects (33%) outnumbered the inhibitory ones (6%). The stimulatory effects occurred mainly in the bone marrow samples of the patients with highly malignant NHL. The observations are compatible with the idea that the membrane endopeptidase (CALLA, CD10) participates in processes controlling the proliferation and differentiation of hematopoetic cells by cleaving the neuropeptides and related hemoregulatory peptides.

Bone Marrow↗

PubMed1998

[[Long-term bone marrow culture].

Long-term bone marrow culture is an experimental in vitro model of hematopoiesis imitating conditions in vivo. It contains hematopoietic elements at various stages of differentiation as well as a supportive stromal microenvironment. Primitive hematopoietic stem cells of mesenchymal origin, the long-term culture initiating cells proliferate and differentiate into different cell types, giving rise to the adherent stromal layer and to various hematopoietic elements attached to it or floating freely in the supernatant medium. The stromal layer keeps the hematopoietic cells aggregated, helps their mitosis, differentiation and maturation by cell-to-cell contact, produces hematopoietic growth factors (cytokines), and forms the extracellular matrix required for cell attachment. Hematopoiesis occurs without exogenous growth factors. The appearance and development of the stroma, the proliferation and differentiation of hematopoietic progenitor cells, and the production of cytokines differ in long-term cultures of the normal and of pathologically altered bone marrow. Long-term bone marrow culture is applied in fundamental studies of normal and pathologically altered hematopoiesis, in pharmacological research, in the purging of residual leukemia cells from bone marrow autotransplants, and in the gene transfer. It is also suitable for testing carcinogenic and toxic chemicals causing hematopoietic damage through occupational or habitual exposure.

Bone Marrow Cells↗

PubMed1998

[Membrane metalloendopeptidase (CD10/CALLA): distribution, physiologic and pathophysiologic functions and its inhibitors].

Membrane metalloendopeptidase EC 3.4.24.11 (Enkephalinase, neutral endopeptidase, NEP) is a cellular ectoenzyme, immunophenotypically identified as the leukocyte cluster of differentiation CD10 or CALLA (common acute lymphoblastic leukemia antigen). Immunological, biochemical and molecular biology techniques have identified tis cell membrane feature in various organs: brain, cardiovascular system, lung, placenta, kidney etc. The CD10 immunophenotype is a common feature of lymphoblasts in acute lymphoid leukemia not expressing the T- or B-markers. The enzymatic activity of CD10/NEP possibly influences normal lymphocyte ontogeny by proteolytic cleavage of the regulatory peptides. The substrates of CD10/NEP in the kidneys are (see the list of abbreviations) ANP, adrenomedullin and PAMP; in the brain, the substrates are enkephalins and oxytocin; in the lung, bombesin, BLP, GRP, neuromedin C, substance P and neurokinin A; in the cardiovascular system, angiotenisin II, bradykinin and CGRP; in the gut, VIP; on the neutrophil membrane, fMLP etc. Some substrates are not strictly tissue-specific, e.g. substance P. Preclinical and clinical trials explore possibilities of therapeutic application of the inhibitors of neutral endopeptidase, such as thiorphan in the management of pain, diarrhoea, depression, arterial hypertension and asthma. Other possibilities of application include the treatment of hyalinomembranous disease and prevention of neurotoxicosis in tetanus and botulism.

Humans↗

PubMedDate not supplied

[Skin cell culture: utilization in plastic surgery and laboratory studies].

Skin is the largest organ of the human body (8-10 kg, 1.5-2.0 m2, 10(11) cells of epidermal, mesenchymal and neural origin). Although endowed with remarkable regeneration ability, the recovery after major injuries viz. burns requires appropriate surgical treatment, temporary coverage of defects and supportive measures. Large defects are covered with viable transplants of autologous or allogeneic skin, frozen or lyophilized human and animal skin, bioartificial tissues made of synthetic or biodegradable materials, sheets of keratinocytes cultured in vitro. The use of autotransplants is limited by the size of preserved skin areas as well as by general condition of the patient. Allotransplants collected from cadavers or volunteers are rejected after 1 or 2 weeks and thus afford only temporary coverage. Grafts of human or animal skin devitalized by lyophilization or freezing in glycerol accommodate connective tissue and blood vessels ingrowing from the graft bed but eventually dissolve. Artificial skin consists of collagen, chondroitin or similar fiber network (substituting the dermis) covered by semipermeable silicon foil (substituting the epidermis). After healing in, the silicon foil is peeled off and replaced by skin autotransplants or autologous keratinocytes grown and expanded in vitro. The technique for massive production of human keratinocytes, invented some twenty years ago, has been applied for clinical purposes by several specialized centers. During the culture period of approximately three weeks the keratinocyte population may enlarge five to ten thousandfold. Keratinocytes obtained from a 1.5 cm2 piece of skin (half of a postal stamp) may thus yield progeny sufficient for the coverage of 1.5 m2, which is almost the total body surface. The period required for culturing autologous keratinocytes is bridged by temporary transplants and vigorous supportive treatment of the patient. Cultured keratinocytes display all essential features of keratinocytes in situ. They divide and differentiate, express membrane structures required for intercellular communication and reception of signals regulating cell division and differentiation, secrete cytokines. In addition to clinical application, the culture of human keratinocytes is a convenient and useful model for studies of cellular biology. This review is illustrated by first examples of keratinocyte cultures grown in our laboratory.

Cell Culture Techniques↗