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Biomedical subjects

Z Dabrowski

Publications and source records attributed to Z Dabrowski.

At least 19 recordsLinked to original sources
PubMed2007

Haematopoiesis in snakes (Ophidia) in early postnatal development.

The occurrence of haematopoiesis has been studied in various parts of the spine and in the ribs in four species of snakes (Boa constrictor L., Elaphe guttata L., Lamprophis fulaginosus Boie., Bothrops jararaca Wied.) from hatching until 150 days of postnatal development. Marrow spaces are formed by chondrolysis with various time frames depending on the studied species. Marrow cells egress to the general circulation in two ways: via migration through the endothelial cells lining the venous sinuses or by the rupture of protrusions. Erythroblasts are present in the lumen of marrow sinuses suggesting their final maturation there. Various relationships of the spleen to the pancreas have been found. No myelopoietic foci occur in the spleen, liver or kidney of any of the studied species. However, erythropoiesis (sparse islets) has been observed in Bothrops jararaca spleen.

Animals↗
PubMed2002

Haematopoiesis and a new mechanism for the release of mature blood cells from the bone marrow into the circulation in snakes (Ophidia).

This is the first description of haematopoiesis in snakes. Studies were carried out on the following species belonging to Ophidia: Bothrops jararaca, Bothrops jararacusu, Waglerophis merremii, Elaphe taeniura taeniura, Boa constrictor,and Python reticulatus. Smears of the peripheral blood and histological preparations from the vertebrae, ribs, liver, and spleen were studied under a light and electron microscope. Myeloid cells were present in the following locations in the vertebrae: the neural spine, zygoapophysial processes, floor of the neural canal, lacunae in the bodies of vertebrae and also inside the ribs. Although the vascular system was well developed, especially around the ribs, vessels inside the marrow cavities were scarce, both in the ribs and elsewhere where haematopoiesis was found. Venous sinuses were well developed in the vertebrae and in the rib regions from their costal head towards the middle area. They consisted of one layer of fine endothelial cells. Mature cells in the process of migration into the general circulation were only sporadically encountered when venous sinuses were studied on perfusion-fixed specimens. In contrast, almost every sinus venosus contained protrusions directed towards the lumen, filled mostly with mature and immature blood cells. Various stages of their formation were seen in the cross sections of venous sinuses ranging from small, newly formed to large, elongated ones, filled with many fully developed and some maturing blood cells. In many cases the apices of the protrusions were ruptured, and mature blood cells, as well as a few immature ones, were seen in their vicinity. This observation led us to a new hypothesis that blood cells are released from the extravascular space into the lumen of venous sinuses. In snakes, these cells are released into the systemic circulation mainly via the rupture of protrusions filled with mature blood cells and, to a lesser degree, by transcytosis as known in mammals. In the spleens from young specimens, 1-2 foci of haematopoiesis were encountered where lymphopoiesis predominated. Haematopoiesis was not detected in the liver.

Animals↗
PubMed2002

Hematopoiesis in snakes (Ophidia).

Locations of the hematopoietic tissue have been described in the following ophidian species: Bothrops jararaca, Bothrops jararacusu, Waglerophis merremii, Elaphe teniura teniura, Boa constrictor, and Python reticulatus. Studies were carried out on perfusion fixed vertebrae, ribs, spleen, liver, thymus, and kidney. Routine histological technique was applied using both light and electron microscopy. Hematopoietic tissue was found in the following locations of the vertebrae: neural spine, neural arch, postzygophysis processes, hypapophysis, vertebral centre. Moreover, intense hematopoiesis was found inside the ribs. In the spleen and thymus, only lymphopoiesis was found. Hematopoietic islets in the spleen were sporadically found only in young specimens. No hematopoiesis was observed in the liver and kidney. In the studied species, there were no differences in the location of hematopoietic tissue. A new model of mature and immature blood cell release to the lumen of marrow sinuses different from that known to operate in higher vertebrates is proposed.

Animals↗
PubMed2000

The activity of erythrocyte enzymes and basic indices of peripheral blood erythrocytes from workers chronically exposed to mercury vapours.

The influence of occupational exposure to mercury vapours on the activity of the red cell enzymes [glucose-6-phosphate dehydrogenase (G-6PD), acetylcholinesterase (AChE), glutathione reductase (GR) and superoxide dismutase (SOD)], as well as on peripheral blood indices [erythrocyte number (RBC), HCT, Hb, MCHC] and on serum concentrations of iron, ferritin, transferrin and total iron binding capacity (TIBC), was assessed. Studies were carried out on 46 men aged between 21 and 56 years (X = 39 +/- 10.4) exposed to mercury vapours during their work from 7 months to 32 years (= 14.7 +/- 10.8). The control group consisted of 35 healthy workers aged between 20 and 54 years (X = 33.6 +/- 9.8) not exposed to chemical nor physical agents. In both groups studied, there were 50% and 34.3% smokers, respectively. The activity of studied red cell enzymes--G-6PD, AChE, GR and SOD--was estimated according to the colorimetric methods described by Beutler and expressed as international units per gram of hemoglobin (IU g Hb(-1)). Peripheral blood cell parameters were determined using an automatic cell counter. The concentration of serum iron and TIBC was determined using colorimetric methods (Beckman), while that of ferritin and transferrin by nephelometric methods. The time-weighted average (TWA) of mercury concentration in the air determined before the study was 0.0028 mg m(-3). Statistical analysis of the data was performed using either the Cochran and Cox C-test or the Student's t-test. The medium mercury concentration in the urine was 77.44 +/- 48.15 microg l(-1). In the group exposed to mercury vapours, a significant decrease was found in G-6PD activity (23.9%, P<0.001), GR (18.8%, P<0.001), and SOD (5%, P<0.001) with a concomitant increase in AChE activity (35.9%, P<0.001) was found. Moreover, a statistically significant increase occurred in HCT and RBC, and a decrease in MCV and MCHC as well as increases of ferritin (130.9%, P<0.001), transferrin (118.4%, P<0.001) and TIBC (11.2%, P<0.05). Our results indicate that long-term exposure to mercury vapours induces changes in the activity of red cell enzymes--G-6PD, AChE, GR and SOD--and may also influence other important hematological parameters of the peripheral blood.

Acetylcholinesterase↗
PubMed2000

[Treatment of pseudoarthrosis of long bones by surgical stabilization and a transfer of in-vitro cultivated bone marrow interstitial cells].

The paper presents the results of surgical stabilization of pseudoarthrosis of long bone augmented by a transfer of in vitro cultivated bone marrow interstitium cells in 4 patients. In three cases a Zespol external fixation device was applied without opening the pseudoarthrosis. One patient was treated by open reduction of the bone fragments with the use of frozen spongiose bone grafts. The mean age of the patients was 30.2 years. In two cases the pseudoarthrosis had developed in the tibia, in the remaining two cases it developed in the ulna. The pseudoarthrosis was present for a mean time of 2.5 years. In all cases healing of the pseudoarthrosis was observed after a mean time of 3.7 months.

Adult↗
PubMed1999

Rheological properties of red blood cells (including reticulocytes) in patients with chronic renal disease.

Hemodialysis is a method of treatment of patients suffering from terminal renal disease and consists in removing uremic toxins from blood. The influence of hemodialysis on rheological properties of red blood cells was ascertained. We studied the deformability of RBC after density gradient separation of whole blood drawn from patients with renal disease before and after dialysis. The improvement in deformability of cells from the top layers was observed in postdialysis samples.

Anemia↗
PubMed1995

Emperipolesis of marrow cells within megakaryocytes in the bone marrow of sublethally irradiated mice.

The incidence of megakaryocytic emperipolesis was studied in the bone marrow of normal and X-irradiated mice. Two groups of mice received total body irradiation with a single dose of 5 Gy and one of the two groups had been treated with a radioprotective drug, ethiofos (WR-2721), before irradiation. Mice from a third group remained unexposed to irradiation and served as controls. The Wright-Giemsa stained bone marrow smears were analyzed every 5 days during a 30-day period, starting 1 day after irradiation. The number of megakaryocytes exhibiting the phenomenon was determined and expressed as an average value for every experimental group. The frequency of megakaryocytic emperipolesis was less than 15% of megakaryocytes from control smears but increased to 34% in mice that had only been irradiated and to 43% when mice were treated with WR-2721 before irradiation. In the last case, i.e., irradiation and treatment with a radioprotective drug, a positive correlation between the macrocytic megakaryocytes and elevated emperipolesis was noted. Under light microscopy, there were no signs of phagocytosis; engulfed cells remained unaltered with their normal structure intact. Granulocytic, erythroid, and lymphoid cells appeared to be the most frequent marrow cells engulfed by mature megakaryocytes. The number of incorporated cells in one megakaryocyte ranged from 1 to 3, though occasionally more than 6 were seen in macrocytic megakaryocytes. Based on our findings and on a review of the associated literature, we believe emperipolesis is an interesting cellular phenomenon related to the fast passage of marrow cells across the marrow-blood barrier, especially through the cytoplasm of megakaryocytes in response to an increased demand for cell delivery. The high demand for cell delivery which occurs after irradiation may cause certain mature bone marrow cells to take a transmegakaryocyte path to enter the circulation of the blood. Irradiation seems to have an immediate effect (observed after 24 h) on emperipolesis, suggesting that a humoral factor is involved in the pathogenesis.

Amifostine↗
PubMed1994

Effect of low-energy laser power on the bone marrow of the rat.

The effect of low power laser light upon the haematopoietic system of rats and also upon the basic haematological parameters was studied. A HeliumNeon continuous emission laser (632.8 nm; max. power 5 mW) and a Galium arsenide semiconductor pulse laser (904 nm; power 80 mW; pulse duration 200 ns) were used as light sources. Intact skin on the hind legs of rats was exposed, over a section of the femur. Peripheral blood analysis carried out before and after the experiments. These indicated that AsGa laser light induced a decrease in bone marrow mastocytes and peripheral blood basophils with an increase in the number of eosinophils. An increase in mitotic activity in the bone marrow was observed in the exposed groups of animals. No significant changes in Hb, Ht, erythrocyte or reticulocyte levels in the peripheral blood were noted, nor was there an increase in megakaryocyte emperipolesis.

Animals↗
PubMed1993

Bone healing after bone marrow stromal cell transplantation to the bone defect.

In experimental studies on rabbits, osteogenic properties of stromal cells were confirmed after in vitro growth for 7 and 14 d. The cell suspension was percutaneously transplanted into a surgically produced bone defect in the rabbit's radius. The bone scar produced was X-rayed, and histologically and mineralogically examined after 10, 20 and 40 d follow-ups. Differences in the bone defect healing process (the healing rate and the type of bone tissue produced) were shown between the experimental and the control foreleg. Within the experimental foreleg, healing was considerably accelerated with compact bone formation on a membranous matrix, whilst in the control foreleg, a coarse, fibrous woven bone on a cartilaginous matrix was dominant.

Animals↗
PubMed1993

Inhibition of delta aminolevulinic acid dehydratase activity by aluminum.

1. Studies were performed regarding the effects of aluminum chloride and aluminum nitrate in concentrations of 5 mg/kg of body weight on the delta aminolevulinic acid dehydratase activity, iron level and hematological parameters. Wistar rats were exposed to these pollutants for 10, 20, 40 and 80 days. 2. The results demonstrated that aluminum chloride was more toxic than aluminum nitrate and both treatments brought about significant changes in these parameters in Wistar rats bone marrow. 3. The toxic effects of aluminum chloride and aluminum nitrate are manifested by a significant decrease of delta aminolevulinic acid dehydratase activity in the bone marrow of rats. 4. The iron level in bone marrow with aluminum chloride and aluminum nitrate gradually dropped after 10, 20, 40 and 80 days of intoxication. 5. In the peripheral blood a significant decrease in the erythrocyte count, hemoglobin level, hematocrit value and an increase in mean corpuscular hemoglobin (MCH) were also found in experimental animals.

Aluminum↗
PubMed1993

Effect of haemodialysate and its peptide fractions on acetylcholinesterase activity in erythrocytes from healthy subjects and patients with terminal renal failure.

The effects of haemodialysate and its three peptide fractions on acetylcholinesterase (AChE, E.C. 3.1.1.7) activity in erythrocytes from healthy subjects and patients with terminal renal insufficiency treated by repeated haemodialyses have been studied. It was shown that erythrocytes from haemodialysed patients display an increased activity of the enzyme if compared with those from healthy subjects. Neither haemodialysate nor any of its three peptide fractions, when incubated with erythrocytes from healthy subjects and from haemodialysed patients, have altered the activity of the enzyme, except for fraction III at the highest concentration. This fraction exerted an inhibitory effect on AChE activity of the erythrocyte derived from healthy subjects.

Acetylcholinesterase↗
PubMed1992

Effect of haemodialysate and its peptide fractions on lactate dehydrogenase activity in erythrocytes from healthy subjects and patients with end-stage renal disease.

The effect of haemodialysate and its 3 peptide fractions on lactate dehydrogenase activity in erythrocytes was studied in patients treated by repeated haemodialysis for end-stage renal disease and in healthy subjects. Erythrocytes from dialyzed patients showed significantly lower LDH activity than those from healthy subjects. After a 3-h incubation with haemodialysate (675 and 450 micrograms protein/ml), or its peptide fraction III (270 and 190 micrograms protein/ml), a significant inhibition of LDH activity was observed. On the other hand, neither haemodialysate nor its peptide fractions inhibited LDH activity in red blood cells from patients with end-stage renal disease treated by repeated haemodialysis.

Blood Proteins↗
PubMed1992

[Changes in erythrocyte shape in children treated with chlorpromazine].

Children suffering from schizophrenic psychosis were treated with chlorpromazine for 21 days. Changes in erythrocyte shape were studied by scanning electron microscopy. It was found that the percentage of stomatocytes in sick children was significantly greater than in healthy children. There was no such a difference in case of echinocytes.

Child↗
PubMed1991

Blood flow in different regions of bone marrow after short-term exercise.

Total and regional blood flow was studied in femoral bone marrow of rats exposed to a short-term exhaustive exercise. The 10 micron microspheres labeled with 58Co were injected into femoral artery and the subsequent radioactivity yield was measured in 3 regions of the bone marrow (proximal metaphysis, diaphysis and distal metaphysis). Following exercise a rise of blood flow in the metaphyseal regions was accompanied by a fall in the diaphyseal area. The changes did not alter, however, the total blood flow rate in bone marrow which remained constant irrespective of the heavy exercise load.

Animals↗
PubMed1990

Effect of recombinant human alpha interferon (INF) on chronic granulocytic leukaemia (CGL) clonogenic growth of bone marrow haematopoietic progenitors.

The effect of recombinant alpha interferon (INF) to the colony stimulating factor (CSF) production was examined with in vitro culture of the bone marrow of patients with chronic granulocytic leukaemia (CGL). It could be found that addition of interferon into a suspension of preincubated phytohaemagglutinin (PHA) lymphocytes from peripheral blood represents an inhibity factor for colony and cluster formation in autologic human marrow cultures.

Bone Marrow↗
PubMed1990

Effect of recombinant human alpha interferon (INF) and antilymphocyte globulin (ALG) on normal and aplastic anaemia haematopoietic progenitor cell growth.

The effect of recombinant alpha interferon (INF) and of antilymphocyte globulin (ALG) to the colony stimulating factor (CSF) production was examined with in vitro culture of the bone marrow of healthy and of aplastic anaemia (AA) persons. In healthy persons the supernatant of lymphocytes preincubated with PHA and ALG was found to show a stimulating effect to clonogenic properties of marrow progenitors, the mentioned effect being not in proportion to the concentration value. Similar properties are shown by interferon in these persons. In patients with aplastic anaemia, a considerable stimulating ALG effect to the granulocytic formation of colonies and a lesser stimulating effect of interferon were shown.

Anemia, Aplastic↗