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Biomedical subjects

C Salat

Publications and source records attributed to C Salat.

At least 37 records · Page 2Linked to original sources

Levels of the terminal complement complex, C3a-desArg and C1-inhibitor in adult patients with capillary leak syndrome following bone marrow transplantation.

Capillary leak syndrome (CLS) is a severe complication after bone marrow transplantation (BMT). To investigate whether there is a pathogenetic role of the complement system, we monitored the levels of the terminal complement complex C5b-9 (TCC) and C3a-desArg as indicators of an activation of the complement system and the inhibitor of the classical pathway of the complement cascade, C1 inhibitor (C1-INH), in 48 bone marrow transplant recipients from 1 week before to 5 weeks after transplantation. Capillary leak syndrome developed in 7 out of 48 patients between days 1 and 12 after BMT. Complement activation as indicated by TCC levels was more pronounced in patients with CLS (n = 7) from day -8 to +28 (p < 0.05; day -1) and the elevation of TCC levels lasted longer in CLS patients (peak day 21) than in patients without this complication (peak day 7). Mean C3a-desArg levels were highest in patients with CLS reaching a peak at day 7. During the early posttransplant period a significant elevation of C1-INH levels (p < 0.01 and p < 0.05 respectively) compared with baseline levels (day -8) was found in patients with and without CLS, which was more pronounced in those patients with CLS (p < 0.05). Although we could not observe an absolute C1-INH deficiency as compared to healthy individuals our data support the presence of a relative deficiency of the inhibitor which might explain the reported beneficial effects of C1-INH substitution in BMT related CLS.

Adult↗

[Hypercoagulability in patients with veno-occlusive disease after bone marrow transplantation].

BACKGROUND: Veno-occlusive disease (VOD) leads to obliteration of small intrahepatic venules and is one of three most important complications with fatal outcome after bone marrow transplantation (BMT). The etiology of VOD is not completely understood. Endothelial cell injury induced by the conditioning myeloablative radiochemotherapy with subsequent activation of the coagulation cascade seems to be a crucial step in the pathogenesis of the disease. PATIENTS AND METHODS: We investigated tissue plasminogen activator (tPA), its main inhibitor (PAI-1) and the natural anticoagulants protein C and S by enzymimmunoassay prospectively in 32 bone marrow transplant recipients. RESULTS: VOD developed in four patients. They presented with extremely elevated levels of PAI-1 after BMT whereas tPA levels remained low. Additionally a transient decrease of protein S was found one week after BMT which was more pronounced in VOD patients. No protein C deficiency was observed. CONCLUSION: Our data suggest that hypofibrinolysis due to an excess of PAI-1 may be involved in the pathogenesis of VOD. The determination of PAI-1 may be useful to recognize the development of VOD and facilitate the decision for thrombolytic therapy with rtPA. A decrease of protein S may play a role as a cofactor in the early phase after BMT.

Bone Marrow Transplantation↗

Parameters of the fibrinolytic system in patients undergoing BMT: elevation of PAI-1 in veno-occlusive disease.

Veno-occlusive disease (VOD) represents one of the more frequent and most severe complications after BMT. The pathophysiology of VOD is poorly understood. To investigate a possible link between endothelial cell damage and VOD, tissue plasminogen activator (tPA) and its inhibitor (PAI-1) were measured in 32 patients as endothelial cell-derived parameters of the fibrinolytic system. A nearly fivefold increase (mean 103.9 ng/ml, range 22.6-582.4 ng/ml, p < 0.05) in PAI-1 levels was found in the four patients who developed VOD compared with patients without this complication (mean 22.2 ng/ml, range 1.4-131.6 ng/ml). No significant difference was found in tPA levels between patient groups with or without VOD or other complications following BMT, indicating a shift of the fibrinolytic balance towards hypofibrinolysis particularly in patients with VOD. We conclude that alterations of the fibrinolytic system occur in patients undergoing BMT. Hypofibrinolysis seems to be at least one factor in the pathogenesis of VOD and the determination of PAI-1 might be helpful for diagnosing the disease. Our data also may explain the reported successful treatment of VOD by recombinant tPA.

Bone Marrow Transplantation↗

[Thrombocyte transfusion. Indications, side effects and problems].

The transfusion of platelet concentrates now represents one of the most common therapeutic measures employed in transfusion medicine. In particular the development of new, aggressive forms of chemotherapy has rapidly increased the need for platelet concentrates over the last few years. The aim of the present study is to describe the major indications and discuss briefly the side effects and problems associated with the transfusion of platelet concentrates.

Blood Group Incompatibility↗

Testicular cancer and Hodgkin disease in the same patient.

BACKGROUND: Although testicular cancer and Hodgkin disease are the neoplasms with the highest incidence in young men, only 13 cases of metachronous and 2 cases of synchronous occurrence in the same person were reported before 1991. METHODS: A 30-year-old man is described, in whom, 2 years after radiation therapy for Stage IIIA Hodgkin disease, a testicular nonseminomatous germ cell tumor developed with metastatic spread to the retroperitoneal lymph nodes, lung, and left supraclavicular fossa. The second case report describes a 31-year-old man in whom a metastasizing nonseminomatous testicular cancer, with elevation of levels of the serum tumor markers alpha-fetoprotein and human chorionic gonadotropin, developed simultaneously with axillary lymphadenopathy that was histologically confirmed Hodgkin disease. RESULTS: After five cycles of cisplatin-based chemotherapy and secondary retroperitoneal lymphadenectomy, the patient with metachronous disease has remained in complete remission for 8 years. The patient with synchronous occurrence has been disease-free for 14 months after five cycles of chemotherapy consisting of cisplatin, etoposide, and doxorubicin (Adriamycin, Adria Laboratories, Columbus, OH). CONCLUSIONS: The metachronous and synchronous occurrence of testicular cancer and Hodgkin disease is a rare association of two curable neoplasms. The presence of both malignant neoplasms should be taken into consideration in young male patients, especially if disease distribution diverges from a regular pattern.

Adult↗

[Storage of thrombocyte concentrates: quality control by in vitro bleeding test].

BACKGROUND: The increasing demand for single-donor platelet concentrates necessitates the storage of these blood products prior to transfusion. Quality control of these platelets, however, is still a problem. Most of the available techniques are time-consuming and require sophisticated equipment and specifically trained personnel. The present paper describes a new method for quality control of stored platelet concentrates. MATERIALS AND METHODS: Single-donor platelet concentrates were stored for 7 days; daily aliquots were taken and the in vitro bleeding time (Thrombostat 4000) and platelet aggregation (aggregometer) were determined. RESULTS: The in vitro bleeding test can be handled simply and fast. The results are comparable with those of platelet aggregation tests. CONCLUSION: The in vitro bleeding test provides a good alternative to the conventional methods commonly used for quality control of platelet concentrates.

Bleeding Time↗

White cell depletion of single-donor platelet preparations by a new adsorption filter.

A newly developed adsorption filter has been evaluated for the removal of white cells (WBCs) from platelet concentrates. It consists of surface-modified polyester fibers and can be used at the patient's bedside. WBC mean removal rate was 98.8 +/- 0.9 percent, and platelet recovery was 99.0 +/- 0.7 percent. The aggregation curves (ADP, collagen) and hypotonic shock response of platelets were not influenced by the filtration, and the plasma electrolyte and lactate dehydrogenase concentrations were unaffected. Transmission and scanning electron micrographs showed no difference in platelet ultrastructure before and after filtration. Determination of posttransfusion platelet recovery did not reveal any significant difference from that of nonfiltered platelets. The tested filter seems to be a suitable device for WBC depletion of single-donor platelet concentrates at the bedside.

Adenosine Diphosphate↗

[Production of leukocyte-poor thrombocyte concentrates: results with a new kind of filter system].

A newly developed filter-system (Sepacell PL) for the removal of leukocytes from single donor platelet concentrates was tested. It removes contaminating leukocytes by 99.9%, the platelet loss was calculated as less than 1%. Platelet ultrastructure and function do not seem to be altered by the filtration. Therefore, the tested filter system seems to be a suitable device for leukocyte depletion of single donor platelet concentrates. Further clinical studies, however, are necessary to prove the efficiency of the filter system in preventing alloimmunization in vivo.

Blood Transfusion↗

Ultrastructural and cytochemical characterization of subcellular fraction of plasmalemmal origin obtained from uterine longitudinal smooth muscle.

The role of Ca2+-ATPase as the driving force for active calcium uptake, involved in the relaxation of smooth muscle, was studied. It was shown by immunocytochemistry that Ca2+-ATPase activity was localized at the plasma membrane level of longitudinal smooth muscle of pregnant rat uteri (18-20 days). To study calcium regulation in uterine longitudinal smooth muscle, 2 microsomal fractions (F1 and F2) were obtained, enriched in plasma membrane material (Lalanne et al., 1984, in: Calcium Regulation in Smooth Muscles. INSERM series, 124, pp. 283-292). In the present paper this material is characterized at both morphologic and cytochemical levels. Both fractions are ultrastructurally heterogeneous: (a) thin sections clearly show 2 populations that differ in vesicular shape and size; (b) negative staining also shows differences in membrane structure, which could be related to biochemical differences and/or to the well known heterogeneity of the plasma membrane. Two reactions (PATAg and concanavalin A-biotin-avidin-ferritin), allowing visualization of cell coat glycans, were performed on F1 and F2 and on thin sections of longitudinal smooth muscle. Plasma membrane and almost all the vesicles of F1 and F2 are reactive. It is concluded that these 2 fractions are characteristic enough for studying, at the molecular level, the ability of plasma membrane to control calcium circulation in uterine smooth muscle.

Animals↗

Distribution of sympathetic nerve endings within the rabbit carotid body: a histochemical and ultrastructural study.

The distribution of sympathetic (noradrenergic) nerves within the rabbit carotid body was investigated by fluorescence microscopy and electron microscopy. With the Falck-Hillarp method, fluorescent nerve fibres were found associated with blood vessels and type I/type II cell groups. After the injection of 6-hydroxydopamine, degenerating nerve profiles were found near blood vessels, near type I/type II cell groups and in contact with type II cells. Following the administration of [3H]noradrenaline, labelled nerve profiles were observed in close association with blood vessels and around cell groups; a few labelled nerve profiles were observed in contact with type II cells. With a modified chromaffin method, chromaffin nerve profiles were found around blood vessels, around type I/type II cell groups and their sensory nerve supply and in contact with type II cells. It was shown that for about one-third of the chromaffin nerve profiles, the nearest structure (in the plane of section) was a type I/type II cell group. Furthermore, the mean distance between chromaffin nerve profiles and blood vessels and between chromaffin nerve profiles and type I/type II cell groups was about the same (2.2 microns and 2.7 microns respectively). These results suggest that the carotid body sympathetic innervation might have, in addition to its vasomotor function, a direct action on the chemosensory structures. This hypothesis is discussed in the light of currently available physiological data and a comparison is made with the role of the sympathetic innervation in other sensory systems.

Animals↗

The liquid crystalline nature of the cytoskeleton in epidermal cells of the chaetognath Sagitta.

The chaetognaths have a multilayered epidermis, which is not covered by cuticle, except in the head region. Two kinds of cells are found in the epidermis: the filament-rich cells, adjacent to the basement membrane, and superficial cells, which are filament poor. The filament-rich cells, which are linked by gap junctions and columnar junctions, are highly developed in the collarette region, which joins the head and the trunk. As elsewhere in the epidermis these cells are covered by the filament poor cells which are linked by zonulae adhaerentes, gap junctions and septate junctions. The filaments present in the inner cells of the collarette form a twisted fibrous arrangement, which shows parallel series of nested arcs when observed in oblique section. Such systems are well known in numerous skeletal materials and correspond to polymerized analogues of certain liquid crystals. The amount of connective tissue is extremely reduced in Sagitta. One can hypothesize that filament-rich cells are abundant in regions which undergo strong deformations. This is the case in the collarette, in contact with the basement membrane of the epidermis (which in turn is in contact with a myotendinous system), in a region where ingested prey must go through the general cavity where there is high internal pressure.

Animals↗

The primary body-wall musculature in the arrow-worm Sagitta setosa (Chaetognatha): an ultrastructural study.

The primary musculature of Sagitta is mainly made up of two kinds of alternating fibers, A and B. These fibers differ markedly in their localization in the muscular tissue, by the development of their SR and their mitochondria, and the shape of their myofibrils. Their contractile apparatus is similar and possesses myofibrils of regular thickness with very short I bands, flanked by invaginations which are large compartments communicating with the extracellular space. This fiber diversity appears and is maintained in the presence of an apparent common innervation. Nerve ending-like structures are scattered in the epidermis against the basement membrane and there are no nerve beneath this. The presence of at least two kinds of fibers in the primary musculature and the presence of the secondary musculature would suggest that the displacements of sagitta may be more complex than is generally admitted. The specializations of the trunk musculature underline the degree of specialization in the Chaetognatha phylum.

Animals↗

Ultrastructural studies of the junctional complex in the musculature of the arrow-worm (Sagitta setosa) (Chaetognatha).

In the A fibres of the primary musculature of Sagitta, the junctional complex is made up of three kinds of junctions. From the apex to the base they occur in the following order: an apical zonula adherens, a columnar zonula then columnar maculae intermingled with gap junction. Each columnar junction joins two intracellular filament networks in adjacent cells; this cytoskeleton is largely developed around the nucleus of the A fibres and in close relation with the contractile apparatus, especially at the I band level. The B fibres, which never reach the general cavity, lack zonula adherens and columnar zonula. The columnar junction constitutes a new type of junction which seems to belong to the adherens kind. At their level fibrous columns cross the extracellular space, joining the membranes. Each column faces two cytoplasmic densities localized against the cytoplasmic leaflets of the membranes. A cytoskeleton composed of bunldes of cytoplasmic filaments is in close contact with these cytoplasmic densities. The great number of columnar junctions and associated cytoskeleton assure the cohesion of the tissue and the distribution of contractile forces in the absence of connective tissue. The abundance of gap junctions can account for the metabolic and ionic coupling of the fibres.

Animals↗

The junctional complex in the intestine of Sagitta setosa (Chaetognatha): the paired septate junction.

The junctional complex of the intestine of Sagitta setosa has been studied in tissues stained with uranyl acetate or after lanthanum impregnation, and by freeze-cleavage. All types of junctions have been characterized in both perpendicular and tangential planes. From the apex to the base of the cell the following junctions occur in this order: a zonula adhaerens; a septate junction where the septa occur in pairs; a pleated sheet septate junction; and numerous gap junctions of the A-type. From the upper part of the cells inwards to the septate junction, the membranes follow a relatively straight path. In the lower part of the cells the membranes are deeply interdigitating. At the intersection between 3 cells a very different junction is to be observed where small units, periodically disposed, bind the membranes of the 3 adjoining cells. Each unit is composed of 3 short segments which bind the cell membranes to a central ring 16.6 +/- 2.3 nm in outer diameter. The paired septate junction constitutes a new type. Its main features are that the septa are paired and occur in 2 formations, one the 'loose formation', with elements between the septa of each pair, and the other, a 'tight formation'. After lanthanum impregnation, the thickness of each septum is seen to be about 3 nm and the undulation period 12.6 +/- 1.6 nm. On freeze-fractures 10-nm particles are found on crests on the PF face and in furrows on the EF face. The possible significance of this type of junction is discussed. The junctional complex described is analogous to those found in various invertebrate epithelia.

Animals↗