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Biomedical subjects

M Horvath

Publications and source records attributed to M Horvath.

At least 19 recordsLinked to original sources
PubMed2003

Idiopathic autoimmune thrombocytopenia: evidence for redistribution of platelet antibodies into the circulation after immunoadsorption treatment.

Platelet antibodies are detectable in only about 50% of patients with chronic autoimmune thrombocytopenia (AITP). We determined platelet antibodies against GPIa/IIa, GPIb/IX, GPIIb/IIIa, and GPV and reticulated platelets in three female patients with AITP, before and after immunoadsorption treatment. None of the three patients' sera contained platelet antibodies prior to treatment. Thereafter, anti-GPIIb/IIIa, anti-GPIb/IX (n = 3), and anti-GPV (n = 1) were detectable in the patients' sera. These antibody specificities were also found in the eluates from the immunoadsorption columns. Only one patient had elevated levels of reticulated platelets. Immunoadsorption treatment did not induce a sustained increase of platelet counts in any patient. Immunoadsorption treatment in AITP can induce redistribution of antibodies into the circulation.

Adolescent↗
PubMed2003

Quality of packed red blood cells and platelet concentrates collected by multicomponent collection using the MCS plus device.

The demand for blood components is constantly increasing, while the exclusion criteria for donors are strengthened in order to reach maximal safety for donors and patients. To counterbalance reduced availability of volunteers, multicomponent collections (MCC) is an attractive approach to produce more than one component during a single apheresis procedure from one donor, such as packed red blood cells (PRBCs) and platelet concentrates (PCs). Further, the exposures of patients to a limited number of donors reduces the possibility of alloimmunization and transfusion-related diseases. We measured the quality of PRBCs and PCs obtained by MCC, using the MCS+ device with the LDPRBC program, Revision B, and compared them with the quality of manually collected PRBCs and PCs collected with the Revision C2 of the MCS+. We found higher pH levels and lower hemolysis assessed by means of fHb and K+ in the supernatant of PRBCs over the whole storage period of 42 days in MCC-derived PRBCs. The functional metabolism assessed by intracellular ATP was higher in PRBCs collected by MCC than in manually collected units. Furthermore, PCs obtained during MCC showed an increase in p-selectin expression on day 5 of storage compared to PCs collected with the Revision C2 of the MCS+. The p-selectin expression on MCC platelets was within the range of p-selectin expression found in PCs obtained by other apheresis devices. These results indicate less storage lesion in MCC-derived PRBCs compared to manually collected units and no compromise in the quality of MCC PCs obtained in the same apheresis procedure.

Adenosine Triphosphate↗
PubMed2001

A new flow cytometric method for simultaneous measurement of residual platelets and RBCs in plasma: validation and application for QC.

BACKGROUND: Guidelines for the preparation of FFP in Austria and Germany require the quantification of residual RBCs in plasma. However, currently there is no validated method for enumeration of RBC counts as low as 1 x 10(9) per L. STUDY DESIGN AND METHODS: A new flow cytometric method was developed for QC, to simultaneously determine if fresh unfrozen plasma contains residual platelets and RBCs. This method uses test tubes (TruCount, Becton Dickinson Immunocytometry Systems) that contain a known number of brightly fluorescent polystyrene beads. Plasma is pipetted into these tubes and mixed with FITC-labeled anti-CD41 and PE-conjugated anti-glycophorin A MoAbs. Acquisition can be performed on a flow cytometer after an incubation period of 15 minutes. RESULTS: Individual standard curves for platelet counts revealed excellent correlation coefficients (r>0.998). Platelet counts were validated against simultaneous measurements by using a cell counter and a hemocytometer. While the flow cytometric method slightly overestimated platelet counts of >40 x 10(9) per L by 10 percent, its precision in the critical range was very good-that is, a deviation of platelets < or = 1 x 10(9) per L from target values, which was even better than microscopic enumeration. The limit of sensitivity was <0.5 x 10(9) per L of platelets. RBC counts were also validated against simultaneous measurements made with a second cell counter. Standard curves for RBC counts also revealed excellent correlation coefficients (r>0.997). The limit of sensitivity was <0.25 x 10(9) RBCs per L. Platelet counts in plasma obtained by plateletpheresis or plasmapheresis ranged from 3 to 60 x 10(9) per L. About 25 percent of all plasma samples had platelet counts greater than the allowed upper limit of 25 x 10(9) per L, while all plasma samples contained fewer RBCs than the upper limit of 6 x 10(9) per L. CONCLUSION: This newly developed method provides a simple, quick, precise, and easily reproducible tool for simultaneous measurement of residual platelets and RBCs in fresh plasma.

Erythrocyte Count↗
PubMed2001

Impaired platelet function among platelet donors.

BACKGROUND: Platelet transfusions are effective for the prevention and treatment of bleeding in patients with disorders of platelet number and/or function. In recent years plateletpheresis concentrates have outnumbered pooled platelet concentrates, albeit with significant differences between nations. Thus, the platelet quality of individual donors has become increasingly important. The aim of this study was to gain an estimate for the prevalence of impaired platelet function among platelet donors. STUDY DESIGN AND METHODS: We determined the inter-donor variability in platelet plug formation with a PFA-100 analyzer, the prevalence of impaired thromboxane formation, and effects of the density in alpha2 integrin polymorphism and density. RESULTS: (i) Collagen-epinephrine induced closure time (CEPI-CT) showed a great inter-subject variability in platelet donors and was higher than in healthy controls (p = 0.008). One-fifth of donors had abnormal CEPI-CT values and 11% exceeded >300 s (max measurable value). (ii) Decreased serum thromboxane B2 levels were found in 9% of all donors, compatible with surreptitious intake of cyclooxygenase inhibitors or with an aspirin-like defect. CEPI-CT correlated inversely with TxB2-levels in donors and controls. (iii) The density of the alpha2-integrin correlated negatively with CEPI-CT and CADP-CT values in controls, but was not responsible for the observed impaired platelet function in donors. (iv) Finally, the ABO blood group system modulates closure times. CONCLUSION: In sum, a large number of platelet donors present with prolonged closure times. Decreased thromboxane formation and frequent platelet donation partly account for this observation.

Adenosine Diphosphate↗
PubMed2000

The Influence of Explanations for Selection Test Use, Outcome Favorability, and Self-Efficacy on Test-Taker Perceptions.

Previous research has shown that an explanation for an event can affect reactions to that event. This study examined this effect within a selection context by varying the type of explanation (causal, ideological, referential) and outcome favorability. A sample of 202 undergraduates completed a selection test and reported their perceptions of that test both before and after the outcome was known. Both the type of explanation and outcome favorability interacted with participants' self-efficacy in determining perceptions of validity and fairness. Implications and directions for future research are discussed. Copyright 2000 Academic Press.

Journal Article↗
PubMed1999

Effects of nitric oxide on platelet activation during plateletpheresis and in vivo tracking of biotinylated platelets in humans.

BACKGROUND: The use of platelet transfusions has risen considerably over the last few years, which leads to the collection and transfusion of a greater number of donor plateletpheresis units. Plateletpheresis activates platelets in platelet concentrates, which determines the degree of the storage lesion subsequently observed. STUDY DESIGN AND METHODS: As nitric oxide (NO) is a potent inhibitor of platelet aggregation and activation, a placebo-controlled crossover trial was performed in healthy young male volunteers to determine whether the NO-donating compound, sodium nitroprusside (SNP), decreases platelet activation during apheresis and whether activated (p-selectin+) platelets circulate in vivo after transfusion. The study also investigated whether nonradioactive biotin labeling of apheresis platelets is feasible for the study of platelet recovery after transfusion in humans. RESULTS: Platelet activation increased after plateletpheresis in the platelet components, but SNP did not inhibit platelet activation during apheresis, as measured by the percentage of p-selectin expression and the secretion of soluble p-selectin and RANTES. Only a minor increase in p-selectin+ platelets was seen in peripheral blood at 60 minutes after transfusion of the platelets, a rise that was considerably less than that calculated in p-selectin+ platelets if they all were recovered as activated platelets after transfusion. Biotin-labeled platelets averaged 1.5 percent at 10 minutes after transfusion and increased slowly to 2.6 and 3.4 percent after 60 minutes and 24 hours, respectively (p<0.05). CONCLUSION: SNP does not decrease platelet activation during apheresis and subsequent storage, and only a minor proportion of activated (p-selectin+) platelets circulate after transfusion in men. Moreover, biotin labeling of PCs can safely be used in humans for the study of platelet recovery after transfusion, and measuring recovery at 1 hour may lead to an underestimation of the true recovery when activated platelets are transfused.

Biotinylation↗
PubMed1998

Hydatid cyst of the kidney.

We report a case of hydatidosis of the kidney and stress the importance of the different radiological modalities. In the presented case, diagnostic radiological procedures included plain radiography of the abdomen, intravenous urography, ultrasonography, computerized tomography and magnetic resonance imaging. The combination of all the radiological findings lead to a correct pre-operative diagnosis, which is important as cyst rupture and spillage may cause anaphylactic reaction.

Adult↗
PubMed1994

Extranodal non-Hodgkin lymphoma of the head and neck.

Non-Hodgkin lymphoma (NHL) is the second most frequent malignant tumor in the head and neck, squamous cell carcinoma being the most frequent. NHL often appears in extranodal localisations. In the head and neck, two distinct extranodal sites are recognised: extranodal lymphatic localisations or involvement of the ring of Waldeyer, and extranodal extralymphatic localisations. In this study we reviewed the imaging features of 55 patients who showed extranodal NHL-localisations to investigate whether we could find specific imaging characteristics. There are no pathognomonic signs. However, if more than one extranodal mass is detected, if the mass appears huge without necrosis or ulceration, if the mass is associated with large, non-necrotic nodes, the diagnosis of non-Hodgkin lymphoma can be suggested; however, it is usually not possible to exclude other pathological processes with absolute certainty.

Adult↗
PubMed1993

Myogenous or arthrogenous limitation of mouth opening: correlations between clinical findings, MRI, and clinical outcome.

The reproducibility and predictive power of MRI diagnosis was evaluated in a group of 70 patients with limited mouth opening. The predictive reliability of the MRI findings was assessed by comparing the images with a final clinical diagnosis that was based on the initial clinical diagnosis, adjusted and refined, when possible, by findings made during the treatment period (conservative treatment in 51 patients, conservative and surgical treatment in 19 patients). The overall reproducibility of the MRI interpretation by the radiologist appeared very good. The predictive reliability was excellent for normal disc position and fair for anterior disc displacement with reduction. For disc displacement without reduction, however, the predictive power was questioned because of false-positive MRI findings.

Adolescent↗
PubMed1993

[Traumatic bilateral testicular dislocation].

The authors report one case of bilateral traumatic dislocation of the testes. A rapid analysis of literature enable to emphasize the usual mechanism (motorcycle accident), different anatomic types and therapeutic behaviour; immediate closed reduction and more often, surgical orchidopexy.

Accidents, Traffic↗
PubMed1992

Congenital arterial anomaly in the middle ear presenting as a glomus tumor.

A case of congenital agenesis of the cervical internal carotid artery with rerouting via the inferior tympanic artery and the embryonic hyoid artery to the horizontal internal carotid artery is presented. At otoscopy the anomaly simulated a glomus tumor. CT scan, by demonstration of the absence of the vertical portion of the carotid canal, the enlargement of the inferior tympanic canaliculus, and the soft tissue mass within the middle ear in continuity with the horizontal internal carotid artery, diagnosed the anomaly very accurately.

Angiography↗
PubMed1992

Extranodal non-Hodgkin lymphoma of the head and neck presenting as a mandibular swelling: report of two cases.

We report two cases of extranodal extralymphatic non-Hodgkin lymphoma presenting as a mandibular swelling. In one case the masseter muscle was involved, suggestive of a non-epithelial process. In the other case the mandible was involved by a mixed osteolytic bone process. Extranodal non-Hodgkin lymphoma should be considered when dealing with a mass lesion in the masticator space.

Biopsy↗
PubMed1991

New trends in computed tomography of the head and neck.

Pathology in the head and neck region is now often examined using MR imaging. However, CT remains a very valuable tool for staging of tumors and lymph nodes in the pre- and postoperative periods. In cases of sinusitis, CT has completely replaced conventional radiography. Moreover, CT helps in differentiating hypointense spots seen in the paransal sinuses on MR. In dental radiology, CT is superior to pantomography in detecting root resorption due to impacted teeth. Thanks to the development of new scanners, three-dimensional reconstructions are possible and scanning times are reduced.

Head↗