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Biomedical subjects

P Cech

Publications and source records attributed to P Cech.

At least 19 recordsLinked to original sources
PubMed2002

Morphology and some biomechanical properties of human liver and spleen.

The aim of the study was an experimental determination of some morphological and mechanical properties of human liver and spleen (amount of collagen in organ capsules, their critical tension and density), followed by a definition of the threshold of critical acceleration, above which the organs can be injured during a car crash. Experiments were done on 33 fresh cadavers (18 males, 15 females; age 3 months to 88 years), and completed by sled tests on dummies testing the loads of both hypochondrial regions protected by air bags and/or seat belts. Results obtained were the following: (1). liver: capsule collagen 14-35%, critical tension 0.066-0.386 MPa, density 0.92-1.19 g/ml, critical acceleration 48-155 g; (2). spleen: capsule collagen 1.8-24.4%, critical tension 0.022-0.652 MPa, density 0.85-1.25 g/ml, critical acceleration 33-149 g. Loads of both hypochondrial regions measured on dummies during a predefined sled test were 34-67 g. Results obtained were evaluated qualitatively and discussed from the point of view of their possible use in future passive safety engineering and design calculations.

Acceleration↗
PubMed2001

[The Coris, a married couple native to Prague and Nobel laureates].

The husband and wife Carl Ferdinand Cori (1896-1984) and Gerty Theresa Radnitz-Cori (1896-1957), two of five Prague-born Nobel laureates (the only ones in medicine), have so much slipped away from the citizens' memory in the course of the half-century totalitarian rule over the country of birth, that hardly anybody knows them nowadays, nothing to say of their relation to Prague. At pains to rescue them from oblivion, a recent search for the lost traces of Coris and their ancestors had revealed a number of hitherto unknown facts that have fundamentally contributed to the Corian genealogy; identification of both forgotten birth-houses (6 Salmovská st., 29 Petrská st.) at long last resulted in placement of memorial tablets (October 26th, 2000) to display the birth-place's pride and gratitude.

Biochemistry↗
PubMed2001

[The surname of Adamkiewicz in the medical terminology in the last three decades of the 20th century].

Nearly eighty years after his death, Albert Adamkiewicz (1850-1921) has still been persisting in both the history of medicine owing to his work and in the medical terminology owing to eponymy: since his flourishing period toward the end of the XIXth century, the surname Adamkiewicz has entered the language of science as a proper-name constituent of anatomical, pathological, neurological, surgical as well as orthopaedic terms, combing with the appellatives stain, corpuscle or demilune, reaction or test, serum, syndrome as well as artery. Estimation of the actual vitality of particular eponymous terms compared with non-eponymous synonyms had to be the aim of the presented search in the scientific literature a century after. In contrast with the inert non-periodical (encyclopaedic) literature, periodicals have revealed all the eponymous terms fallen in oblivion except the 'Adamkiewicz artery' that has only recently been introduced in encyclopaedias although constantly preferred in periodicals of the period under investigation (appearing in 75% articles) over the most frequent non-eponymous synonym 'arteria radicularis magna / great(er) radicular artery' (scarcely 11% articles). Thanks to the 'artery' - joining furthermore several synonyms to appear nearly in 86% articles altogether - the surname Adamkiewicz persists in the living language of science; that is why its bearer ought to be remembered and mentioned even on the threshold of the XXIst century.

History, 19th Century↗
PubMed1987

High- and low-affinity receptors regulate platelet responses to phorbol diesters and teleocidin.

We examined binding of 3H-phorbol dibutyrate (3H-PDBu) to gel filtered human platelets (GFP) and discovered that GFP possess two classes of receptors for phorbol diesters (PDE). High-affinity (HA) receptors, approximately 5000/GFP, bound 3H-PDBu with an apparent dissociation constant (KD) of approximately 12 nM. Low-affinity receptors were approximately 5 times more numerous (2.4 X 10(4)/GFP) and had a 10-fold lower affinity for 3H-PDBu (apparent KD = 115 nM). The potencies of phorbol myristate acetate (PMA) and PDBu paralleled their binding affinities to the PDE receptors. Teleocidin (Tel), although structurally distinct from PDE, competed with 3H-PDBu for its HA-receptors (KI Tel = 1.9 nM). Binding of PDE to HA- or LA- receptors was rapid, reversible, saturable and stereospecific. The HA- and LA-receptors modulated different platelet responses. HA-receptors regulated the secretion of beta-thromboglobulin from alpha-granules and the release of N-acetyl-beta-D-hexosaminidases from lysosomes. LA-receptors mediated both platelet aggregation and the release of serotonin from dense granules. This is the first demonstration of two physiologically active classes of PDE/Tel receptors in human platelets, and demonstrates that particular platelet responses may be directed by distinct classes of receptors for specific agonists.

Binding, Competitive↗
PubMed1986

Effects of phorbol diesters and teleocidin on normal human platelets.

Teleocidins are newly described indole alkaloid tumor promoters that are structurally distinct from phorbol diesters (PDE). We compared the effects of teleocidin and selected PDE on platelet aggregation, secretion and aspects of arachidonate metabolism. Three tumor-promoting PDE (phorbol myristate acetate (PMA), phorbol dibutyrate (PDBu) and 4-beta-phorbol didecanoate (4-beta-PDD] and a non-tumor promoting PDE (4-alpha-phorbol didecanoate (4-alpha-PDD] were used. Teleocidin and tumor promoting PDE caused platelet aggregation after a delay that was inversely related to tumor promoter concentration and also triggered secretion of alpha- and dense granules and selective release of lysosomal enzymes. Aggregation and its associated 125I-fibrinogen binding to platelets were both inhibited by Na2EDTA. 4-alpha-PDD was ineffective. Analysis of platelet aggregation responses and activation kinetics revealed that PDBu was 11.7 times less potent than teleocidin PMA, or 4-beta-PDD. Neither PDE nor teleocidin stimulated 14C-arachidonate release from normal human platelets, and both aggregated aspirin-treated platelets. These results show that representatives of two structurally distinct classes of tumor promoters, phorbol diesters and indole alkaloids, are potent activators of platelet aggregation, fibrinogen binding, and granule/lysosomal secretion, by a mechanism that bypasses arachidonate release and formation of cyclooxygenase-dependent arachidonate metabolites.

Arachidonic Acids↗
PubMed1984

Oxygen metabolism of phagocytosing human polymorphonuclear leucocytes in diabetes mellitus.

Zymosan stimulated oxygen metabolism was investigated in polymorphonuclear leucocytes (PMN) from 6 diabetic patients. Oxygen uptake and superoxide production were continuously measured in the presence of autologous or control serum and non-opsonized zymosan, or in the absence of serum and preopsonized zymosan. The only significant impairment in the diabetic cells studied was a lower oxygen uptake in the presence of autologous serum. This defect was normalized by addition of control serum or by omitting the serum and stimulating with opsonized zymosan. In the absence of serum, the oxygen consumption was markedly diminished in only one subject, whereas two subjects showed a decrease of superoxide production in the presence of control serum. An inverse correlation between fasting glucose concentration and oxygen uptake could be demonstrated. However, exposure of normal PMN to hyperglycemic glucose concentration in vitro did not significantly alter their oxygen metabolism, suggesting that glucose alone could not be the only factor responsible for the impaired oxygen consumption in diabetic cells.

Aged↗
PubMed1984

Heterogeneity of human neutrophil phagolysosomes: functional consequences for candidacidal activity.

Opsonized yeast phase Candida albicans, incubated with human neutrophils, are internalized into two classes of phagosomes. One class, termed "unsealed vacuoles," comprises approximately 40% of the total and maintains functional communication to the cell's exterior that is sufficient to permit ingress of dyes, such as trypan or methylene blue. The remaining cell-associated yeasts are contained in "sealed vacuoles," completely sequestered from the external milieu. Approximately 71.8% of C albicans within sealed vacuoles are rendered nonviable within 60 minutes, whereas only 14.5% of organisms within unsealed vacuoles are killed during this time. We conclude that vacuolar sealing mechanisms are imperfectly developed in normal human neutrophils and that incompletely sealed vacuoles support antimicrobial processes substantially less well than do completely sealed ones.

Candida albicans↗
PubMed1984

Phagolysosomal pH of human neutrophils.

Human neutrophils sequester yeast cells or zymosan particles in two classes of phagocytic vacuoles: sealed and unsealed. The pH of sealed vacuoles was measured by a newly devised fluorometric procedure that used fluoresceinated zymosan particles, derived from Saccharomyces cerevisiae, as a pH probe. Five minutes after initiation of phagocytosis, sealed vacuoles were alkaline, exhibiting a pH of 7.80 +/- 0.19 (mean +/- SEM). Their acidity subsequently increased, so that the pH fell to 7.38 +/- 0.25 after 15 min. 6.35 +/- 0.35 after 30 min, and 5.68 +/- 0.26 after 60 min. The implications of these findings for neutrophil microbicidal mechanisms are discussed.

Blood Bactericidal Activity↗
PubMed1983

Partial myeloperoxidase deficiency in preleukemia.

In seven subjects with partial and apparently acquired form of myeloperoxidase (MPO) deficiency, some functional properties of neutrophils (PMNs) were studied. Five patients suffered from preleukemia, one from diabetes mellitus and one from carcinoma of the breast with bone marrow metastases. Intracellular bactericidal activity, oxygen consumption and superoxide radical production were within normal limits. In three patients with preleukemia, the serum opsonic activity was markedly reduced (less than m-3SD) in an autologous system, but normal in the presence of pooled normal serum. Decreased opsonic activity was also found when these patient's sera were assayed in the presence of normal PMNs. Since the levels of IgG and C3 were comparable in the patients' sera and the pooled serum, a deficiency of another unknown opsonin or the presence of an opsonization inhibitor has to be postulated. The partial MPO defect apparently doesn't decrease the intracellular killing of Staphylococcus aureus by PMNs. The known susceptibility to bacterial infections in preleukemia may be explained by the reduction of serum opsonization conducing to a secondary decrease of the ingestion and killing of bacteria by the PMNs.

Blood Bactericidal Activity↗
PubMed1982

Partial myeloperoxidase deficiency.

Neutrophil myeloperoxidase (MPO) activity was analyzed by a semi-quantitative cytochemical method in 268 subjects divided into several groups. 17 subjects with significantly reduced MPO activity were found: 11 of 23 in the preleukemia group, 2/14 AMLs, 1/20 myeloproliferative syndrome, 1/7 carcinoma with bone marrow metastases, 1/33 diabetes mellitus and 1/50 normals. Only in the preleukemia group, was MPO significantly reduced in comparison to the normal group (p less than 0.005). The high frequency of acquired MPO deficiency in preleukemia represents a useful criterium for this diagnosis. Furthermore, in these patients, as well as in the other subjects studied, no apparent correlation between MPO level and infection could be demonstrated.

Candidiasis, Chronic Mucocutaneous↗
PubMed1982

Lasting Hb F reactivation and Hb A2 reduction induced by the treatment of Hodgkin's disease in a woman heterozygous for beta-thalassemia and the Swiss type of the heterocellular hereditary persistence of Hb F.

A remarkable augmentation of Hb F and a reduction of Hb A2 were observed in a Sicilian woman during and after a course of treatment for Hodgkin's disease. An inverse correlation between the proportion of Hb F and Hb A2 was found over an 8-year period, as well as in populations of red blood cells fractionated by density gradient. She exhibited two genetic defects, the Swiss type of heterocellular hereditary persistence of fetal hemoglobin and a beta-thalassemia trait, which were confirmed by the study of the hemoglobin synthesis and by a family study. The lasting reactivation of Hb F synthesis is attributable to the interaction of several acquired and inherited factors.

Adult↗
PubMed1981

[Tumors and myelomonocytic leukemia].

Extramedullary solid tumors of early granulocytic and monocytic precursors are a rare manifestation of acute non lymphoblastic leukemias. They may develop during the course, or be the presenting sign, of leukemia. We describe a case of myelomonocytic tumors involving the skin and the stomach as primary manifestations of leukemia. Two months later the patient developed acute myelomonocytic leukemia with a rapidly fatal course. At autopsy, multiple tumors were found in the skin, the peridural space, the muscles, the peritoneum, the pleura and in several organs, such as in the lungs, the kidneys, the gallbladder and in the whole gastrointestinal tract. The many synonyms of these tumors, the localisation, the chronology of the clinical manifestations and the various problems in the diagnosis are discussed. In the differential diagnosis of histiocytic lymphoma, identification of myelomonocytic differentiation in neoplastic cells should be done, using special techniques, such as immunoperoxidase and cytochemical stains for esterases.

Aged↗
PubMed1980

[Cutaneous manifestations of thrombocythaemia associated with myelofibrosis in a patient suffering from psoriasis and treated by PUVA (author's transl)].

Cutaneous manifestations of thrombocythaemia are caused by vascular lesions, either haemorrhagic or thrombotic, affecting above all the microcirculation of the extremities. The authors report a case of thrombocythaemia associated with myelofibrosis discovered by ischaemic lesions on the toes which appeared at the beginning of PUVA therapy for psoriasis. The type of vascular lesions generally depends on the platelet count. In the presence of these cutaneous manifestations, the determination of both platelet counts and functions may orient the diagnosis toward a myeloproliferative syndrome.

Adult↗