Mitochondrial DNA D-loop haplogroup contributions to the genetic diversity of East European domestic chickens from Russia.

To elucidate geographical and historical aspects of chicken dispersal across Eastern Europe, we analysed the complete mitochondrial DNA D-loop sequence of 86 representatives from chicken breeds traditionally raised in the territory of the East European Plain (Orloff, Pavlov, Russian White, Yurlov Crower, Uzbek Game and Naked Neck). From the 1231-1232 bp D-loop sequence, 35 variable sites that defined 22 haplotypes were identified in modern chicken. All populations, except Uzbek Game, exhibited high values of haplotype and nucleotide diversity suggesting a wide variation in maternal diversity. Inclusion of mtDNA sequences from other European and Asian countries revealed representatives from this study belonging to haplogroups A, E1 and C1. We also assessed fossil chicken material dated to the 9th-18th century from archaeological sites in Northern and Eastern Europe. Three haplotypes found in the fossil specimens belonged to haplogroup E1, while one sample dated to the 18th century was assigned to the C1 haplogroup. This is the first report of the occurrence of the C1 haplogroup in European chicken populations prior to the 20th century based on the fossil material. These results provide evidence for a relatively recent introduction of all haplotypes other than E1 into the East European chicken gene pool with the significant impact of the C1 haplogroup mainly distributed in Southern China.

HE ROLE OF REPETITIVE SEQUENCES IN THE EVOLUTION OF SEX CHROMOSOMES IN BIRDS.

In this paper, we analyzed the distribution and the transcriptional activity of different repetitive elements in the sex chromosomes of chicken at the lampbrush stage. Based on these results, we suggest participation of interspersed repeats in the maintenance evolutionarily significant level of variability of heteromorphic sex chromosomes in birds. Analysis of the organization peculiarities of chicken sex chromosome W specific repeats allowed us to hypothesize that the accumulation of tandem repeats enriched with homopurine tracks is significant for the evolution of sex chromosomes.

[Clinical and laboratory presentation of the influenza A (H1N1pdm 2009) in children and adults during the period of 2009-2013 in St. Petersburg].

Comparative analysis of the clinical laboratory data from 419 children and 468 adults hospitalized during the pandemic of A (H1N1pdm 2009) and pre- and post-pandemic periods (2010-2013) showed that the clinical presentation of the pandemic influenza in patients of all ages is generally typical for influenza, and its character is determined by the degree of involvement of lungs in the process. Besides, the incidence of pneumonia in adults is statistically significantly higher than in children. During all compared periods hyperthermia (≥ 39 degrees C), hemorrhagic and dyspeptic syndrome were observed. Some differences in the main clinical manifestations of pneumonia in recovered patients and patients who died of the severe pandemic influenza were observed. The regularities of the cytokine reactions depending on the intensity of intoxication and occurrence of complications were determined in patients of all ages. Medical efficacy of inclusion of antiviral chemotherapeutic agents into complex influenza treatment was proved.

EFFECT OF IRON ON BONE TISSUE METABOLISM AND THYROID FUNCTION IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES SINCE THE ChNPP ACCIDENT. / ВПЛИВ ЗАЛІЗА НА ПРОЦЕСИ МЕТАБОЛІЗМУ В КІСТКОВІЙ ТКАНИНІ ТА ФУНКЦІЮ ЩИТОПОДІБНОЇ ЗАЛОЗИ УДІТЕЙ, ЯКІ ЖИВУТЬ НА РАДІОАКТИВНО ЗАБРУДНЕНИХ ТЕРИТОРІЯХ ПІСЛЯ АВАРІЇ НА ЧАЕС.

OBJECTIVE: identification of clinical and metabolic characteristics of osteogenesis and factors affecting bone mineral density (BMD) in children living in radioactively contaminated territories (RCT) after the ChNPP accident for the use of therapeutic and preventive measures aiming to reduce the incidence of disorders. MATERIALS AND METHODS: Children aged 4 to 18 years old (n = 539) were involved in the study within 4 age groups, namely under 7 years old, 7-10 years old, 10-14 years old, older than 14 years old. Studied parameters in children with a reduced BMD (85-65 relative units and under 65 relative units) were estimated vs. the normative BMD (100-85 relative units) cases. Diagnosis of osteopenia and osteoporosis in children was established according to the BMD T-index. Family history of the relatives of children was studied. Body weight at birth, fractures of the long bones, complaints of osalgia, jaw anomalies, dental caries, presence of obesity, and hypermobility syndrome (HMS) were assessed. Peripheral blood biochemical tests were performed featuring the serum total protein, alkaline phosphatase (APh), calcium, vitamin D, creatinine, serum iron (SI), ferritin, cortisol, pituitary thyroid-stimulating hormone (TSH), and free thyroxine (FT4) assay. BMD was measured and radiation doses in children were reconstructed. RESULTS: BMD depended on the age of children. A direct correlation was established between the cholelithiasis and urolithiasis incidence (р < 0.01), cancer and endocrine diseases (р < 0.05) in the relatives of children that had BMD under 65 relative units. Dental caries developed more often (р < 0.05), while obesity was less frequent (р < 0.05) in the subjects with BMD < 65 relative units. A direct correlation was established between the level of serum creatinine and BMD (р < 0.01), and there was an inverse correlation between the serum APh level and BMD (р < 0.001).Every third child had a vitamin D deficiency. Fractures of long bones and increased content of SI and TSH were characteristic for the children having got osteopenia (BMD within 85-65 relative units), while besides a predisposition to bone fractures the higher levels of SI, APh, cortisol both with calcium deficiency were found in children with osteoporosis (BMD < 65 relative units) compared to the general group with a similar BMD. An increased incidence of HMS was characteristic too. Radiation doses in children with osteopenia were higher than in those with osteoporosis: (1.17 ± 0.09) mSv and (0.92 ± 0.06) mSv respectively (р < 0.05). No correlation was found between the radiation doses and clinical signs, blood biochemistry or BMD. CONCLUSIONS: Study of the functional mechanisms of bone structures in children, depending on their metabolism, had made it possible to reveal the factors that affect bone formation in children living in RCT after the ChNPP accident, and to form the population groups for the timely application of therapeutic and preventive measures aiming to reduce the incidence of disorders of musculoskeletal system.

DRIVERS OF HYPERFERREMIA IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES AFTER THE CHNPP ACCIDENT IN UKRAINE. / ЧИННИКИ, ЯКІ ВПЛИВАЮТЬ НА МЕХАНІЗМИ ФОРМУВАННЯ ПІДВИЩЕНОЇ ЩІЛЬНОСТІ КІСТКОВОЇ ТКАНИНИ У ДІТЕЙ, ЖИТЕЛІВ РАДІОАКТИВНО ЗАБРУДНЕНИХ ТЕРИТОРІЙ, ПІСЛЯ АВАРІЇ НА ЧАЕС.

OBJECTIVE: assessment of clinical-hematological and metabolic-biochemical parameters of the of bone tissue and hormonal regulation depending on the serum iron content and radiation dose values in children living on radiologically contaminated territories after the ChNPP accident in Ukraine. MATERIALS AND METHODS: Children (n = 271) living on radiologically contaminated territories (RCT) of Ukraine were involved in the study. Three study groups were formed according to the serum iron level (SIL), namely group I with SIL 10.0-22.0 µmol/l (n = 92), group II with SIL 23.0-34.0 µmol/l (n = 144), and group III with SIL above 35.0 µmol/l (n = 35). Diseases in the family tree, bodyweight at birth, complaints on osalgia, bone fractures, jaw anomalies, dental caries, and obesity were accounted. Morphometric parameters of erythrocytes and hemogram elements were analyzed. Creatinine, alkaline phosphatase, calcium, total protein, iron, cholesterol, bilirubin, and transaminases were assayed in blood serum. The urine content of the 19 free amino acids, serum content of the free thyroxine (FT4), pituitary thyroid-stimulating hormone (TSH), and cortisol were assayed both with bone tissue density. Individual radiation doses were calculated. RESULTS: In 12.9 % of cases the SIL was > 35.0 µmol/l. Relatives with endocrine diseases were often present in the family tree of children with SIL > 23.0 µmol/l. There were increased urine content of the free amino acids (p < 0.05) and signs of protein degradation under high SIL. Contents of amino acids involved in collagen synthesis and antioxidant status (alanine, serine, glutamine, aspartic acid) and iron metabolism (arginine, leucine) were assayed at the highest levels (p < 0.05). Urinary levels of valine, lysine, and methionine, which are associated with iron metabolism, were decreased (p < 0.05). An inverse correlation (rs = -0.58; p < 0.01) was established between the serum TSH and cortisol levels regardless of the SIL. Serum TSH level directly correlated with urine content of amino acids involved in collagen synthesis. An inverse correlation (rs = -0.55; p < 0.001) was established between the serum TSH level and urine content of tyrosine that is essential for the thyroid hormone (triiodothyronine and thyroxine) synthesis.Cortisol was found having a negative effect on protein synthesis. Inverse correlation was established between the serum cortisol level and urine content of the free amino acids essential for collagen synthesis. There was no dependence of the average radiation dose values on the SIL. An inverse correlation was determined between the patient's radiation dose and SIL > 35.0 µmol/l (rs = -0.29; p < 0.05). CONCLUSIONS: The increased SIL in children living on RCT may occur due to both a genetic predisposition and the acquired factors driving protein and mineral metabolism of bone and their hormonal regulation.

FACTORS AFFECTING MECHANISMS OF INCREASED BONE DENSITY FORMATION IN CHILDREN LIVING ON RADIOLOGICALLY CONTAMINATED TERRITORIES AFTER THE ChNPP ACCIDENT. / ChYNNYKY, IaKI VPLYVAIuT' NA MEKhANIZMY FORMUVANNIa PIDVYShchENOÏ ShchIL'NOSTI KISTKOVOÏ TKANYNY U DITEI, ZhYTELIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII, PISLIa AVARIÏ NA ChAES.

OBJECTIVE: to determine the causes of increased bone mineral density (BMD) based on case history, clinical and laboratory data, including the assay of hormones involved in ossification processes in children, living on radiologically contaminated territories (RCT) after the accident at the ChNPP, compared to the normative BMD patterns. MATERIALS AND METHODS: There were 289 children involved in the study. The 1st group included persons with a BMD above 100 IU, 2nd group - with normative BMD (100-85 IU). Family history of diseases was assessed featuring cancer and endocrine diseases, cholelithiasis, and urolithiasis. Weight of the child at birth, frequency of bone fractures, complaints about osalgia, jaw abnormalities, dental caries, presence or absence of obesity, peripheral blood count, blood biochemical parameters (total protein, creatinine, iron, alkaline phosphatase, calcium), serum pituitary thyroid-stimulating hormone and cortisol were accounted. Children's radiation doses were calculated according to the materials of the «General dosimetric certification of settlements of Ukraine that were exposed to radioactive contamination after the Chornobyl accident¼. RESULTS: Higher than normative BMD values were found in children after puberty, while normative ones - in puberty (р < 0.001), regardless of gender. A direct correlation between the bone fractures frequency was established in children with increased BMD (р < 0.01). Jaw anomalies and dental caries occurred at that significantly less often than in normative BMD (р > 0.05). A direct correlation was established between the obesity and BMD (р < 0.001).Increased alkaline phosphatase activity was inversely correlated with BMD (rs = -0.21; р < 0.05). In children with elevated BMD a direct correlation was established between the level of iron and endocrine disorders in the family history (р > 0.001). Serum level of cortisol was directly correlated with dental caries (р < 0.05). In children, regardless of BMD value, a direct correlation was established between the radiation dose, age and obesity (р < 0.001). CONCLUSIONS: Higher than normative BMD is accompanied by an increased frequency of bone fractures, jaw abnormalities, metabolic changes in bone tissue and bone tissue hormonal regulation in children, which requires application of pathogenetic therapy for the osteogenesis.

ASSESSMENT OF QUALITATIVE CHANGES IN PERIPHERAL BLOOD CELLS IN CHILDREN - RESIDENTS OF RADIOLOGICALLY CONTAMINATED TERRITORIES IN THE LATE PERIOD AFTER THE ChNPP ACCIDENT. / OTsINKA IaKISNYKh ZMIN V ELEMENTAKh PERYFERYChNOÏ KROVI U DITEI ­ MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII U VIDDALENYI PERIOD PISLIa AVARIÏ NA ChAES.

OBJECTIVE: to establish the relationship between quantitative and qualitative parameters of peripheral blood cells(lymphocytes, neutrophilic granulocytes, monocytes, platelets) depending on the type of somatic diseases andannual internal radiation doses from 137Cs in children - residents of radiologically contaminated territories in thelate period after the Chornobyl Nuclear Power Plant (ChNPP) accident. MATERIALS AND METHODS: There were 175 children included in the study comprising residents of radiologically con-taminated territories (n = 79) aged from 4 to 18 years. Annual internal radiation doses in children from 137Cs rangedfrom 0.004 to 0.067 mSv. Certain blood parameters were assessed in a comparative mode in children having got theradiation doses up to 0.01 mSv and higher. The comparison group (n = 96) included children living in settlementsnot attributed to the radiologically contaminated ones. Incidence and type of somatic diseases and its impact onquantitative and qualitative changes in blood parameters (i.e. lymphocyte, neutrophilic granulocyte, monocyte, andplatelet count) were studied. The cell size, state of nucleus, membranes and cytoplasm, signs of proliferative anddegenerative processes were taken into account. RESULTS: Incidence and type of somatic diseases in children did not depend on the annual internal radiation dose.Number of cases of monocytosis was significantly higher among the children exposed to ionizing radiation than inthe comparison group (16.6 % vs. 7.3 %). There were, however, no correlation between these changes and radiationdoses. Number of activated blood monocytes with cytoplasmic basophilia and residues of nucleoli in nuclei washigher in individuals with internal radiation doses > 0.01 mSv. A direct correlation between the qualitative param-eters of monocytes and internal radiation doses was established (rs = 0.60; р < 0.001), as well as a direct correlationof different strength between qualitative parameters of blood cells, indicating their unidirectional pattern depend-ing on the somatic morbid conditions. Regardless of annual internal radiation dose, there was an increase in thenumber of degenerative and aberrant cells vs. the comparison group (р < 0.05), which could be due to the role ofnon-radiation factors. CONCLUSIONS: Results of the assessment of quantitative and qualitative parameters of peripheral blood cells reflect-ed the state of morbid conditions in children and are of a diagnostic value. The identified dose-dependent changesin monocyte lineage of hematopoiesis may be the markers of impact of long-term radionuclide incorporation withfood in children living in environmentally unfavorable conditions after the ChNPP accident.

THYROID DISEASE IN THE LATE OBSERVATION PERIOD UPON CHEMO AND RADIOTHERAPY IN CHILDREN/SURVIVORS OF ACUTE LYMPHOBLASTIC LEUKEMIA. / KhVOROBY ShchYTOPODIBNOÏ ZALOZY PISLIa KhIMIO TA PROMENEVOÏ TERAPIÏ U DITEI, IaKI PERENESLY GOSTRU LIMFOBLASTNU LEIKEMIIu, U VIDDALENOMU PERIODI SPOSTEREZhENNIa.

OBJECTIVE: to assess the thyroid disease in the late observation period in children who had received chemo- andradiotherapy for the acute lymphoblastic leukemia (ALL) taking into account gender, age period and disease sub-type. MATERIALS AND METHODS: The incidence and nature of thyroid disease (hypothyroidism, thyroiditis, and thyroid can-cer) were studied in children-survivors of acute lymphoblastic leukemia (ALL) being in remission from 6 to 25 years.The distribution of patients by leukemia subtypes was as follows: «common¼ - 67.4 %, pre-B - 23.9 %, pro-B andT-cell - 4.3 %. Children had been receiving chemo- and radiotherapy according to the protocol. Regarding the ageof patients at the time of ALL diagnosis the prepubertal, pubertal and postpubertal periods were taken into account.The endocrine diseases in family history, body weight at birth, serum content of free thyroxine, pituitary thyroid-stimulating hormone, cortisol, iron, ferritin and thyroperoxidase antibodies were evaluated and assayed. RESULTS: Thyroid disease in children was emerging in the first 2-3 years after the ALL treatment with an incidenceof 22.8 % (hypothyroidism - 14.1 %, autoimmune thyroiditis - 7.6 %, papillary cancer - 1.1 %). Seven children inthis group had received radiotherapy (12-18 Gy doses) on the central nervous system (CNS). No correlation wasfound between the radiation exposure event itself, radiation dose to the CNS and thyroid disease in the long-termfollow-up period. Thyroid cancer had developed in a child 11 years upon chemo- and radiotherapy. Hypothyroidismwas more often diagnosed in the patients of prepubertal age (rs = 0.49). There were endocrine diseases in thefamily history in about a half of children, being significantly higher than in the general sample (р < 0.05). The bodyweight at birth of a child who had later developed hypothyroidism was less than in children having got thyroiditis(rs = 0.57). CONCLUSIONS: Disorders in endocrine regulation and of thyroid in particular can affect the prognosis of blood can-cer course in the long-term follow-up in children, especially in prepubertal age, which requires systematic supervi-sion by hematologist and endocrinologist.

Precise centromere positioning on chicken chromosome 3.

Despite the progress of the chicken (Gallus gallus) genome sequencing project, the centromeric sequences of most macrochromosomes remain unknown. This makes it difficult to determine centromere positions in the genome sequence assembly. Using giant lampbrush chromosomes from growing oocytes, we analyzed in detail the pericentromeric region of chicken chromosome 3. Without knowing the DNA sequence, the centromeres at the lampbrush stage are detectable by immunostaining with antibodies against cohesin subunits. Immunostaining for cohesin followed by FISH with 23 BAC clones, covering the region from 0 to 23 Mb on chicken chromosome 3 (GGA3), allowed us to map the GGA3 centromere between BAC clones WAG38P15 and WAG54M22 located at position 2.3 and 2.5 Mb, respectively. This corresponds to the gap between 2 supercontigs at the 2.4-Mb position in the current GGA3 sequence assembly (build 2.1). Furthermore, we have determined that the current putative centromeric gap at position 11.6-13.1 Mb corresponds in fact to a long cluster of tandem chicken erythrocyte nuclear membrane repeats (CNM).

[Lampbrush chromosomes of the Japanese quail (Coturnix coturnix japonica): a new version of cytogenetic maps].

Avian oocyte chromosomes are transfomed into giant transcriptionally active lampbrush chromosomes (LBCs) at meiosis 1 diplotene. These chromosomes are a convenient tool for high-resulution cytogenetic analysis. Using differential staining with fluorochromes DAPI and CMA3, we have constructed detailed cytological maps for lampbrush macrochromosomes 1-5 and ZW of the Japanese quail Coturnix coturnix japonica. We also performed a comparative analysis ofmitotic chromosomes and LBCs corresponding to them. We estimated the decondensation coefficient during LBC formation and determined the centromere indices for mitotic and diplotene chromosomes and thus found that different chromosomes and chromosomal regions demonstrate unequal degrees of decondensation.

Search for functional amyloid structures in chicken and fruit fly female reproductive cells.

We conducted a cytological search for amyloid structures in female reproductive cells of Gallus gallus domesticus and Drosophila melanogaster. We have shown that the amyloid-specific dye, Thioflavin S, but not Congo red, stains some cytoplasmic and even nuclear structures in chicken ovaries. In fruit fly eggs both Thioflavin S and Congo red specifically stain eggshell structures such as micropyle, dorsal appendages and pillars. Moreover, these structures, when stained with Congo red, demonstrate birefringence in polarized light, which is a characteristic feature of all classical amyloids. Our data show that female reproductive cells during evolution began to use amyloid fibrils to form various functional structures necessary for development under certain environmental conditions.

PROGNOSIS OF ACUTE LEUKEMIA DEPENDING ON THE IRON METABOLISM PARAMETERS IN CHILDREN AFTER CHORNOBYL NUCLEAR POWER PLANT ACCIDENT. / PROGNOZ PEREBIGU GOSTRYKh LEIKEMII U DITEI PISLIa AVARIÏ NA ChAES ZALEZhNO VID OBMINU ZALIZA.

OBJECTIVE: To determine the influence of iron metabolism on the prognosis of acute lymphoblastic (ALL) and (AML)myeloblastic leukemia at the different phases of chemotherapy in children after Chоrnobyl accident. MATERIALS AND METHODS: 333 children (295 - ALL, 38 - AML) were examined at the stages of chemotherapy. Thecomparison group included 93 children without leukemia. Acute leukemia variants, patients survival, relapses, thenature of disease (live child or died), iron methabolism (morphometric parameters of erythrocytes, SI, SF, STf, TS),manifestations of dyserythropoiesis, bone marrow sideroblast and patients radiation dose were taken into account. RESULTS: In 295 patients with ALL the following variants of leukemia were established: pro-B-ALL in 23, «common¼type of ALL in 224, pre-B-ALL in 29, T-ALL in 19. Thirty eight patients were diagnosed with AML (11 - M1, 19 - M2,8 - M4). Doses of radiation in patients with AL were (2.78 ± 0.10) mSv and they did not correlate with clinical andhematological parameters, disease variant. Relapse rates and shorter survival were in patients with T-ALL, pro-B-ALLand AML with SF levels > 500 ng/ml (p < 0.05). The amount of children with normochromic-normocytic anemias andmanifestations of dysplasia of erythroid lineage elements was greater in the AML than in ALL. SF content in patientswas elevated during chemotherapy and was lower than the initial one only in the remission period. Transferrin wasreliably overloaded with iron: TS (70.2 ± 2.3) % compared with the control group (32.7 ± 2.1) %. Correlationbetween TS and survival of patients was detected (rs = -0.45). Direct correlation between the number of iron granules in erythrocariocytes and SF level (rs = 0.43) was established, indicating the phenomena of ineffective erythropoiesis. CONCLUSIONS: The negative influence of iron excess in the patients body on the hemopoiesis function, manifestations of ineffective erythropoiesis and the course of acute leukemia in children have been established. Changes inferrokinetic processes in children can be the basis of leukemоgenesis development.

[Crossing over in the oogenesis of Gallus gallus domesticus chickens: periodicity in the distribution of chiasmata over the length of chromosomes].

The periodic occurrence of chiasmata was studied in lampbrush chromosomes of the chicken (Gallus gallus domesticus). It was shown that the most probable interference distance in chicken macrobivalents 1-3 corresponded to 24.48 Mb. The distance at which absolute interference is observed in chicken macrochromosomes varies from 5.75 to 9.02 Mb.

Effect of radiation and non radiation environmental factors on children hematopoietic system. / VPLYV RADIATsIY̆NYKh TA NERADIATsIY̆NYKh FAKTORIV DOVKILLIa NA STAN SYSTEMY KROVOTVORENNIa DITEY̆.

OBJECTIVE: Identification of impact of radiation and non radiation environmental factors on development of hematopoi etic abnormalities in children and justification of criteria for the increased risk groups of hematologic diseases. MATERIALS AND METHODS: The results of clinical and hematological survey of 1465 children living in Kyiv, Zhytomyr and Chernihiv regions for the period from 2008 to 2014 were presented. There were 777 children with anemia, 466 with changes in hemogram, 191 with acute leukemia. The irradiation doses, correlation of integrated pollution degree of territories with hematopoietic parameters and course hematologic diseases were estimated. Metal con tent in hair, nails, and blood was determined in 121 children. RESULTS: We have found the most common cause of anemia in children and peculiarities of acute leukemia depend ing on the area integrated contamination. Number of children living in contaminated areas with pro B ALL and T ALL having an initial leukocytosis and unfavorable course of the disease was higher compared to the number of patients from moderately polluted regions (r = 0.47). There is a direct correlation between percentage of children with monocytosis and degree of territory contamination: the 20.2 % of such children lived in the intensively polluted areas and 10,3 % in moderately contaminated ones (p < 0.05). Content of Pb, Cu, Cr, Mn, Zn in biological tissues did not exceed the permissible MAC. Level of Zn in all children was at the lower normal threshold. Individual levels of metals in hair, nails and blood did not depend on gender of patients and their radiation doses. Criteria of increased risk of hematologic diseases in children living in ecologically unfavorable regions were grounded. CONCLUSIONS: Radiation and non radiation environmental factors influencing the development of changes in hematopoiesis and characteristics of the blood system diseases in children play a role in leukeima development processes. These findings are the basis for a further research in the field of radiobiology and ecology.

Lipid-cell interactions. Liposome adsorption and cell-to-liposome lipid transfer are mediated by the same cell-surface sites.

The competitive behavior of solid vs. fluid liposomes in liposome-to-cell adsorption and cell-to-liposome lipid transfer processes was investigated with L cells and FBT epithelial sheets. Binding, transfer and 31P-NMR experiments have demonstrated that: (i) solid liposomes adhere to the cell surface as integral vesicles retaining the entrapped substances; (ii) fluid liposomes are partly disintegrated at the cell surface with concomitant entry of entrapped substances into the cytoplasm, while their lipids remain on the cell surface; (iii) fluid liposomes that escape lysis dissociate from the cell, taking away cell lipid molecules. The latter process underlies the mechanism of cell-to-fluid liposome lipid transfer. In contrast, no lipid transfer occurs between the plasma membrane and solid liposomes. Cell-bound solid liposomes interfere with the transfer of cell lipids to fluid liposomes, while these in turn inhibit the binding of solid liposomes to the cell surface. Moreover, cell-induced aggregation of both fluid and solid freshly added liposomes is also inhibited by preincubation of the cells with either solid or fluid liposomes. Thus, different types of interaction of both fluid and solid liposomes with the cell are mediated by the same (or closely related) sites on the cell surface.

Regulation of intracellular pH by phospholipase A2 and protein kinase C upon neutrophil adhesion to solid substrata.

Adhesion to solid substrata has been shown to increase intracellular pH (pH(i)) of fibroblasts and of other cells (FEBS Lett. (1988) 234, 449-450; Proc. Natl. Acad. Sci. USA (1989) 86, 4525-4529; J. Biol. Chem. (1990) 265, 1327-1332; Exp. Cell Res. (1992) 200, 211-214; FEBS Lett. (1995) 374, 17-20). We have found that the inhibitors of PLA2, 4-bromophenacyl bromide and manoalide, completely blocked the increase of pH(i) and spreading of neutrophils upon adhesion to solid substrata. Inhibition of phospholipase C with neomycin or removal of extracellular Ca2+ affects neither neutrophil spreading nor their pH(i). Inhibition of PKC with H-7 or staurosporin increased pH(i). PMA, an activator of PKC, dramatically decreased pH(i) but did not impair the spreading of neutrophils. The effect of arachidonic acid, a product of PLA2 activity, on neutrophil pH(i) and spreading was similar to that of PMA. H-7, an inhibitor of PKC, partially blocked the effect of arachidonic acid (AA) on pH(i). BW755C, an inhibitor of AA metabolism by cyclooxygenase or lipoxygenase, affected neither the pH(i) nor cell spreading. We propose that the increase of pH(i) upon neutrophil adhesion is mediated by PLA2 activity, while PKC decreased pH(i). AA produced by PLA2 activates PKC, thus forming a feedback regulation of pH(i).

Low-density lipoproteins interact with liposome-binding sites on the cell surface.

Under physiological conditions significant amounts of low-density lipoprotein LDL particles ar taken up by cells independently of specific high-affinity LDL receptors (apo-B receptors). Previously it was established that some cells contain surface sites capable of binding liposomes. We proposed that liposome-binding sites could contribute to LDL interaction with the cell surface via phospholipid molecules of LDL particles. To check this hypothesis we studied the competitive interaction of human LDL and DPPC liposomes with mouse embryo fibroblasts depleted of apo-B receptors by preliminary incubation with LDL. We have found that after removal of the liposome-binding sites from cell lamellae these areas of the cell surface lose their ability to bind LDL.

Adhesive interactions of neutrophils and leukotriene synthesis.

Cell-substrate and cell-cell adhesion of neutrophils has been found to slow down the calcium ionophore A23187-induced synthesis of 5-lipoxygenase (5-LO) metabolites of arachidonic acid. Addition of the exogenous substrate, arachidonic acid (AA), together with A23187, resulted in the enhanced production of leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) by adherent neutrophils in comparison with those by the cells in suspension. We observed also the enhanced production of 5-LO metabolites in attached cells when we stimulated the cells by the combined action of phorbol 12-myristate 13-acetate (PMA) and A23187. Thus, the adhesion to solid substrate and to other cells, an important regulatory factor for the activity of many cells, is a powerful regulator of leukotriene production by neutrophils.

Regulation of intracellular pH by cell-cell adhesive interactions.

As was shown in our previous work, the intracellular pH (pHi) of cultured human fibroblasts depends on cell density. The pHi is low in single cells, higher in cells, forming small groups and maximal in a sparse monolayer. On the other hand, the pHi is low in areas of confluent monolayers. In the present work, we show that the effects of inhibitors of various pH-controlling mechanisms as well as inhibitors of key enzymes in signal transduction pathways depend on the local cell density. We have found that N-ethylmaleimide and 7-chloro-4-nitrobenz-2-oxa-1,3-diazole, known as inhibitors of V-type H+ ATPase, inhibit the elevation of pHi induced by cell-cell contact interactions; meanwhile Cd2+ ions, which inhibit H+ conductive pathway, cause an increase of pHi in a confluent monolayer. Our data revealed also that the Na+/H+ antiporter does not play an essential role in the pHi regulation by intercellular contacts. Inhibitors of phospholipase A2 (4-bromophenacyl-bromide), phospholipase C (neomycin) and protein kinase C (H-7) dramatically change the way the pHi is modulated by local cell density. It is suggested that cell-cell interactions regulate cell activities via modulation of pHi, which is under positive control from phospholipase A2 and under negative control from protein kinase C.

Involvement of ecto-ATPase and extracellular ATP in polymorphonuclear granulocyte-endothelial interactions.

The adhesion of human polymorphonuclear granulocytes (PMN) with confluent human endothelial cells (line EAhy926) and with solid substrate coated by collagen and fibronectin (Fn) was studied by phase contrast microscopy and by the measurement of myeloperoxidase activity. The ecto-ATPase inhibitors suramin and Reactive Blue 2 (RB2) more than doubled the adhesion of PMN to endothelial cells. The cells hydrolyzed added ATP and this reaction was inhibited by suramin and RB2. The degree of ATP hydrolysis during PMN adherence depended on solid substrata and decreased in the order: non-stimulated endothelial cells, TNF-stimulated endothelial cells, collagen-coated surface, Fn-coated surface. In the same order adherence increased. The endogenous level of extracellular ATP in the PMN-endothelial coculture was around 25 nM. We conclude that PMN-endothelial adhesion is counteracted by an ecto-ATPase or by ATP receptors with ATPase activity. Such interactions may play a role in PMN rolling and diapedesis as well as in the pathophysiology of PMN activation by an anergic endothelium.