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Biomedical subjects

J Jakubovský

Publications and source records attributed to J Jakubovský.

At least 19 recordsLinked to original sources
PubMed2005

Conformation study of the membrane models by the Maxwell displacement current technique and oxidative stress.

The role of biological membranes as a target in biological radiation damage is still unclear. Recently much attention has been paid to the dynamic behaviour of the cell membrane. Maxwell displacement current technique (MDC) provides new possibility of conformation study of the membrane models. Oxidative stress can impair macromolecules in the cell on a molecular level. MDC technique enables to study the changes in molecular orientations and/or conformations of cell membranes. The combination of different methods in structural biology can clarify membrane chemical and physical properties.

Biophysical Phenomena↗
PubMed2005

Chondroitin sulphates A, B and C, collagen types I-IV and fibronectin in venous sinus of the red pulp in human spleen.

The morphological relationship of chondroitin sulphates A, B, and C, collagen types I-IV and fibronectin in the wall of venous sinuses of the red pulp in human spleen has not been a focus of interest among morphologists. Regarding the hypothesis that the structure of the spleen lends it the function of a blood filter the substances described in our study might play a significant role in the functional morphology. Of 146 human spleen surgical specimens, groups of 12 specimens each were examined under a light microscope using the method of antibodies against fibronectin, against collagen types I-IV and against chondroitin sulphates A, B, and C. The sections of the red pulp of human spleen stained with hematoxylin and eosin provided limited information about the wall of the sinuses. Chondroitin sulphates A and B were observed on the surface of sinus-lining cells (SLC), and fibronectin was detected on the surface of the annular fibers. Collagen type 11 was observed almost in the same places as chondroitin sulphates A and B. Collagen type IV was present in annular fibers of the wall of the sinus and in the basement membrane, like fibronectin. Chondroitin sulphate was not present in the walls of sinuses. Binding of antibodies against chondroitin sulphate A and against chondroitin sulphate B indicates the presence of chondroitin sulfates on the surface of SLC, where they probably play a role in helping the human organism to recognize alien and self substances. The presence of chondroitin,sulphates A and B probably affects inhibition of binding of cells with collagen type I, but not with fibronectin.

Chondroitin Sulfates↗
PubMed2000

Endotoxin-induced aggravation of preservation-reperfusion injury of rat liver and its modulation.

BACKGROUND/AIMS: In clinical transplantation, exposure of donors to gut-derived endotoxin occurs frequently and may adversely affect liver transplantation therapy. The aim of this study was to investigate: 1) whether brief exposure of rats to endotoxin before liver procurement aggravates the early phase of reperfusion injury of hepatic explants; and if so 2) whether Kupffer cell activation is a contributing factor to liver injury; and 3) whether heparin and pentoxifylline could minimize this effect. METHODS: Male Wistar rats were injected with 0.2-4.0 mg/kg of Escherichia coli lipopolysaccharide 2 h prior to liver harvest. After preservation in University of Wisconsin cold-storage solution, the livers were reperfused using a blood-free perfusion model. To inactivate Kupffer cells, some rats were pretreated with gadolinium chloride or liposome-encapsulated dichloromethylene-diphosphonate before lipopolysaccharide administration. The other rats received lipopolysaccharide with heparin or pentoxifylline. RESULTS: In a dose-independent fashion, lipopolysaccharide impaired portal flow during graft reperfusion. In a dose-dependent way, lipopolysaccharide increased lactate dehydrogenase release into the perfusate and decreased bile flow and bromosulfophthalein excretion. Gadolinium chloride, liposomal dichloromethylene-diphosphonate, heparin, and pentoxifylline reduced lactate dehydrogenase release by 34%, 43%, 59%, and 64%, respectively, and improved functional parameters of the liver. A 52-fold increased neutrophil infiltration in the liver sinusoids after lipopolysaccharide exposure was not affected significantly by the drugs studied; however, heparin reduced markedly neutrophil activation. CONCLUSIONS: The results of this investigation provide direct evidence that aggravation of preservation-reperfusion injury of rat liver by endotoxin is mediated by Kupffer cell-dependent mechanism(s) and it can be minimized by heparin and pentoxifylline.

Adenosine↗
PubMed2000

[Clinical and histopathologic picture of acute appendicitis in children].

A retrospective study of the clinical and histopathological picture of acute appendicitis in children confirms agreement of the evaluation of the finding on the appendix made by the surgeon and pathologist in 72.2% and disagreement in 27.8%. The finding is overrated in 11.3% and underrated in 16.5%. Agreement is closest in phlegmonous appendicitis (88.1%) and lowest in gangrenous appendicitis (54.9%). The most frequently overrated finding is in catarrhal appendicitis (20.7%). The number of missed appendectomies is from the pathologist's point of view significantly lower (21.8%) than from the surgeon's point of view (34.7%). This indicates obviously that it is not possible to make an accurate macroscopic assessment of the progress of appendiceal inflammation. The number of "negative" appendectomies is according to the surgeon 15.8% and according to the pathologist 16.8%, i.e. almost equal.

Acute Disease↗
PubMed1998

Metastasizing adenocarcinoma of the female prostate (Skene's paraurethral glands). Histological and immunohistochemical prostate markers studies and first ultrastructural observation.

The case of a 46-year-old women with well-differentiated adenocarcinoma of the female prostate (Skene's paraurethral glands and ducts) with inguinal metastases is reported. Besides adenocarcinomatous structures, also more solid parts of the tumor and anaplastic regions with dark cells were found on histological examination. Clear cancerous cells were typical for glandular and solid tumor parts. The cancerous cells showed distinct immunohistochemical positivity of prostate specific antigen (PSA) and prostate (specific) acid phosphatase [P(S)AcP]. These are the first published results of electron microscopic examination of formalin fixed tissue showing the ultrastructure of female prostate carcinoma, comparable to that of the male prostate carcinoma. In the female, similar to the male, the prostate carcinoma probably originates from the secretory (luminal) cells of the female prostatic glands.

Acid Phosphatase↗
PubMed1998

[Current knowledge on the functional morphology of the human spleen].

The knowledge on the functional structure of the spleen is gained from the analysis of diseases, and immunological studies. Significant information is gained from model tests and isolated cells. The latter is advantageous in coincidence with the studies of intercellular relations. The main function of the spleen resides in "purification" of the blood. The vascular system, white pulp, red pulp and the marginal zone participate in this process. T-dependent zones of the white pulp are restricted by the circumference reticulum (CR) of periarterial lymphatic sheaths. CR is a morphologic substrate of retro-directional flow of lymphocytes. In addition to T lymphocytes and a certain amount of B lymphocytes, the T-dependent zones contain interdigitizing cells. The B-dependent zones, in addition to lymphocytes, contain dendrite reticular cells. The cords are constituted by varied cellular and extracellular compartments, especially macrophages, fibroblastic reticular cells and various fibrous components. The latest filtration barrier is formed by the wall of sinuses of the red pulp. The achievement of new functional knowledge resides prospectively in the use of lectins, anti-collagen antibodies, fibronectins, proteoglycanes and other various molecules participating in intercellular relations, or morphometric studies, they can provide information on the newest subpopulations of cells in both red and white pulp, that are so far inaccurately defined.

Humans↗
PubMed1996

[Present knowledge of human spleen function].

The human spleen is an important lymphoid organ participating in immune reactions against all types of circulating antigens. It also removes particles of nonantigenic nature from blood circulation. The structure of the spleen, containing specialized cells types, provides a microenvironment where various intercellular interactions occur and determines the course of development of immune and nonimmune reactions. Though the spleen significantly participates in host defense reactions it is not inevitable for life. However, removing of the spleen increases the risk of overwhelming infections by bacteria with polysaccharide capsules.

Animals↗
PubMed1996

[The spleen in hereditary spherocytosis].

Hereditary spherocytosis is the most common inherent, autosomal dominant hemolytic anemia. Mild splenomegaly, venostasis and common decrease of while pulp is characteristic for hereditary spherocytosis. Cords are filled with spherocytes, sinuses can be empty or squeezed. Both sinuses and veins include ghost erythrocytes that lost haemoglobin. They are seen light-microscopically in differential interferent contrast. Macrophages are numerous, sinus lining cells are hypertrophic. Erythrophagocytosis is hardly seen by electron microscope. Not all red blood cells are spherocytes. Spherocytes are seen well in electronmicroscopy. We did not observed transition of erythrocytes through sinus walls. In certain circumstances lots of ferritin is seen both intra and extracytoplasmically. Iron accumulation in cords can result in their fibrosis.

Humans↗
PubMed1996

[Fibronectin and the human spleen].

Fibronectins are glycoproteins with a function of molecular glue. The aim of the study is to encourage interest in processes in extracellular matrix of the spleen. Undigested cryostat or formol-paraffin sections and commercially available antibodies were used. We were mostly successful in extracellular localization of fibronectin in trabeculae, vessel walls and lamellae of circumferent reticulum of periarterial lymphatic sheaths and in the ring fibres of the sinuses. Changes in the amount of fibronectin occurred, for example, in circulation disturbances. In hereditary spherocytosis the ring fibres were reduced. Increase of fibronectin can suggest the development of fibrosis.

Extracellular Matrix↗
PubMed1996

[Traumatic rupture of the spleen. Histopathologic findings].

The most common causes of splenic rupture are blunt injury and surgical intervention in abdominal cavity. Morphological investigation of the spleen often shows but a small capsular laceration as well as haemorrhage and granulocytic infiltration in microscopy of its margins. The laceration may be sometimes difficult to find. There are two types of microscopical haemorrhage. One in sinus-lacking subcapsular tissue zone, the other in deeper layers. In this case the tissue haemorrhage is diffuse, sometimes within or around the marginal zone. The sinuses are neither collapsed nor obturated by any material even close to margins of the wound.

Humans↗
PubMed1996

[Dermoid cyst of the spleen].

The case report of a 14-year old girl is given. In her spleen of the weight of 1580 g an irregular cyst of glossy inner surface and with striking trabeculation developed. It was filled with clear greenish liquid. The wall was formed by hyalinised collagen tissue which was covered by epidermoid and cuboidal epithelium on the inner surface. Vessel conglomerates were frequent, some bleeding or mononuclear infiltrates, foci of giant cell granulation tissue, lymphoid or fatty tissue were present.

Adolescent↗
PubMed1995

[Functional morphology of the spleen].

The spleen was till the first half of the twentieth century considered to represent an organ of no special significance. Nowadays its clearance function and position in the immunity system is thoroughly investigated. Informations on its cellular composition and compartments are sufficient. The problems coinciding with circulation in the spleen are solved. The study of interactions of T and B lymphocytes regarding the development of humoral immunity do not provide clear results. Unclear remain also the relations of extracellular and cellular structures. The localisation of the spleen in blood circulation and large amount of migrating lymphocytes justify its significant position in the protection of host against infections spreading haematogenously. It is not inevitable for survival, but its removal increases the risk of unmanageable infections carried by bacteria with polysaccharide capsules. The microenvironment in the spleen enables intercellular relations and determines the development of immune reactions. Microcirculation enables it to function as a biological filter without the necessity of specialized filtrating structures being present. In consequence of blood filtration everything leaks into the extravasal space. Subsequently all components normally constituting the blood return back into the blood within vessels. That is why no special structures are formed in order to filter individual components from the blood. All components that should not be present in the blood are excluded extravasally. The substances which are not let through the wall of sinuses into the blood, remain in the marginal zone and in the red pulp. The macrophages of the marginal zone and red pulp destroy and degrade the unrequired substances. (Ref. 26).

Animals↗
PubMed1994

[The significance of prostate markers in the orthology of the female prostate].

In addition to knowledge gained in the first half of the 8th decade, the evidence of cross-antigenicity between male prostate and Skene's glands by means of PSA and PSAcP demonstrations in Skene's glands and ducts justifies utilization of the term prostate in both sexes. The authors compared the results of immunohistochemical examination of prostatic markers by means of the PAP method which was used at the beginning of the 8th decade, with that of BSAP technique. Prostatic tissues of 11 females and children at the age ranging from 5 to 71 years were examined. The results gained by means of the BSAP method were identical with those gained by means of the PAP method. Prostatic markers PSA and PSAcP were expressed on the surface and in apical cytoplasm of cells lining the prostatic ducts, and in prostatic glands. The authors proved the expression also in membranes of the stratified cylindrical epithelial cells of the ducts, and in female prostatic fluid in ducts and glands, especially PSAcP. Even though both immunohistochemical methods brought identical results, the authors recommend to prefer the BSAP method to the PAP method due to optically more contrast expression. (Fig. 8, Ref. 36.)

Acid Phosphatase↗
PubMed1994

[The human spleen in idiopathic thrombocytopenic purpura].

Idiopathic (autoimmune) thrombocytopenic purpura (ITP, AITP) represents a relatively frequent impairment. It involves a syndrome of various diseases with a shortened thrombocytes survival caused by anti-platelet antibodies. The majority of cases are of secondary character. Spleenectomy often evokes a complete remission of thrombocytopenia. The study describes morphologic findings in spleens of 30 patients with the clinical diagnosis of ITP/AITP. The findings were gained by light microscopy from formol-paraffin blocks and histochemical findings from cryostat sections of non-fixed tissue. The alcaline and acidic phosphatases, nonspecific esterase, chloracetate esterase, and dipeptydilpeptidase IV were investigated enzymohistochemically. Immunoglobulins were examined immunohistochemically and T lymphocytes by means of monoclonal antibodies. The affinity HPA--Helix pomatia agglutinin, PHA--phytohemagglutinin from Phaseolus vulgaris, SBA--soy-bean agglutinin from Glycine max. and PSA--peas bean agglutinin from Pisum sativum were investigated by means of specific antilectin antibodies. The human spleen during idiopathic thrombocytopenic purpura accumulates neutrophilic polymorphonuclear granulocytes; platelets-stagnate and are destroyed. These processes can be identified in histologic sections e.g. also by means of anti-fibrinogen antibodies. The red pulp contains foam cells to various extent. Besides generally known processes, the white pulp also displays alterations in composition of cellular compartment of the periarterial lymphatic sheaths. Human spleen distinguishes modified blood platelets as alien corpuscles, and thus eliminates them from the blood circulation system by its immunologic and other mechanisms, the details of which still remain to be clarified. (Fig. 6, Ref. 44.)

Humans↗
PubMed1993

The use of lectins identified with specific antibodies in lectin histochemistry of NZB/W F1 mouse kidney.

The affinity of Helix pomatia, peanut, Pisum sativum, soy bean, and wheat germ agglutinins to various nephron parts of NZB/W F1 mice was different and is assumed to be age dependent. The affinity of Pisum sativum agglutinin to basal membranes of small renal vessels increased with the age of NZB/W F1 mice. The wheat germ agglutinin bound to structures with alkaline phosphatase activity.

Animals↗
PubMed1993

Subacute immunotoxicity study of formaldehyde in male rats.

Immune functions were examined in male rats following 28 day oral administration of formaldehyde by gastric tube at dose levels of 0, 20, 40, and 80 mg/kg. Routine parameters examined included hematology, clinical chemistry, and body, thymus, kidney, and liver weights. In addition, cellularity of spleen and lymph nodes, histology of spleen, thymus, lymph nodes, liver kidney, small and large intestines, and histochemistry of spleen and lymph nodes were evaluated. Immune parameters evaluated included serum hemagglutinin antibody response; antibody plaque forming cell response to sheep erythrocytes (lymphocyte-dependent antigen); microbicidal activity of Candida albicans; and phagocytic activity by adhesion of microspheric hydrophilic synthetic particles to leukocyte cell membrane. Body weights were slightly decreased at high dose level (80 mg/kg). The difference was significant when compared to the controls. The lymph node weights were significantly increased in rats receiving formaldehyde. The cellularity of lymphoid organs was not influenced after 28 day exposure to formaldehyde.

Administration, Oral↗
PubMed1992

[Structural basis of appendiceal function in rabbits].

Enzymo-, immuno- and lactin-histochemical methods were used to study the structure of the rabbit appendix wall. The value of some structural components in the function of this part of the intestine is discussed. Some findings were documented electronmicroscopically. In addition to its resorptive function, the rabbit appendix is equipped with a potent defense mechanism against adverse environmental effects of the appendix content. Individual structures of this defensive barrier are closely characterized with regard to cellular equipment and possibilities of its morphological identification.

Animals↗