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Biomedical subjects

A Salama

Publications and source records attributed to A Salama.

At least 55 records · Page 3Linked to original sources
PubMed2001

Management of the oral and maxillofacial surgery patient with thrombocytopenia.

Patients with disorders of coagulation and bleeding can be among the most challenging surgical patients to manage. Intraoperative or postoperative bleeding can contribute to life-threatening complications in even the most "benign" surgical procedures. An adequate number and function of platelets play a critical role in the coagulation pathway. A thorough understanding of platelet physiology and platelet disorders is therefore essential in the management of the thrombocytopathic oral and maxillofacial surgery patient. A careful preoperative evaluation will help the surgeon treat these patients and help prevent potentially catastrophic intraoperative or postoperative bleeding.

Adult↗
PubMed2001

Dipeptidyl peptidase IV (DP IV, CD26) in patients with inflammatory bowel disease.

BACKGROUND: Dipeptidyl peptidase IV (DP IV, CD26), a serine protease with broad tissue distribution and known activity in serum, participates in T cell activation and promotes a Th1 cytokine response, a function in part attributable to its enzymatic activity. We hypothesized that the activity of DP IV in serum and expression of CD26/DP IV in lymphocytes may be altered in patients with inflammatory bowel disease (IBD). METHODS: Serum DP IV activity and CD26 (DP IV)-positive peripheral blood lymphocytes were measured in 110 patients with IBD (Crohn disease (CD): n = 63, ulcerative colitis (UC): n = 47). Additionally, T cell activation antigens (CD25, CD95) and costimulatory molecules (CD28) were evaluated. The same analyses were carried out in healthy volunteers (HC, n = 28). Thirty-nine patients with CD and 28 patients with UC were reassessed 3-6 months after the first visit. RESULTS: In patients with IBD, the DP IV activity in serum was reduced (mean +/- s (standard deviation): 52.8 U/l +/- 16.9 (CD) and 55.7 +/- 15.1 U/l (UC) versus 71.9 +/- 18.4 (HC), P < 0.001). Furthermore, patients with IBD had higher numbers of CD26-positive cells coexpressing CD25 and a higher surface expression of CD26 (DP IV) (mean fluorescence intensity, mean 57.1 (CD) and 59.8 (UC) versus 29.9 (HC), P < 0.001). The DP IV activity in serum showed an inverse correlation with known disease activity scores as well as with the concentrations of orosomucoid in serum. CONCLUSION: The changes of DP IV in patients with IBD highlight alterations at an interface between immune function and metabolism of peptide hormones, with potential importance for the pathophysiology of IBD. Furthermore, these changes may help to refine the assessment of IBD activity.

Adult↗
PubMed2000

Dipeptidyl peptidase IV (DPP IV, CD26) in patients with mental eating disorders.

The notion that patients with eating disorders maintain a functional immunosurveillance in spite of severe malnutrition has attracted researchers for years. Dipeptidyl Peptidase IV (DPP IV), a serine protease with broad tissue distribution and known activity in serum, operates in the cascade of immune responses. Membrane-bound DPP IV expressed on lymphocytes, also known as the leukocyte antigen CD26, is considered to participate in T cell activation. We hypothesized that the activity of DPP IV in serum and expression of CD26 in lymphocytes may be altered in patients with eating disorders. Serum DPP IV activity and the number of CD26 (DPP IV)-positive peripheral blood lymphocytes were measured in 44 patients (anorexia nervosa (AN): n = 21, bulimia (B): n = 23) in four consecutive weekly analyses. The analysis of CD26-positive cells included the characterization of CD26-bright and CD26-dim positive subsets. Additionally, the expression of CD25 (IL-2 Receptor alpha chain) was evaluated to estimate the degree of T cell activation. The same analyses were carried out in healthy female volunteers (HC, n = 20). CD26-positive cells were reduced in patients as compared to healthy controls (mean 40.2% (AN) and 41.1% (B) vs. 47.4% (HC), p < 0.01), while the DPP IV activity in serum was elevated (mean 108.4 U/l (AN) and 91.1 U/l (B) vs. 80.3 U/l (HC), p < 0.01). The potential implications of changes in DPP IV expression and serum activity on--and beyond--immune function are discussed.

Adult↗
PubMed2000

Ceftriaxone-induced immune haemolysis: two case reports and a concise review of the literature.

BACKGROUND AND OBJECTIVES: In this report, we will describe the occurrence of intravascular immune haemolytic anaemia (IHA) associated with ceftriaxone and/or its metabolites in two of our patients. Serological examinations were carried out to demonstrate and characterise the causative antibodies. The findings of all previously reported cases will also be discussed. MATERIALS AND METHODS: Direct antiglobulin tests (DAT) and indirect antiglobulin tests were performed according to standard procedures. Tests for drug-dependent antibodies were performed in the presence and absence of the target drugs and their ex vivo antigens (in the urine of patients treated with the drugs). RESULTS: Ceftriaxone-related haemolysis resulted in the death of one of our patients (patient 2), and caused acute renal failure in the other (patient 1). The DATwas strongly positive for anti-C3d and anti-IgG in one case (patient 2), and for anti-C3d alone in the other (patient 1). The serum of patient 1 reacted with red blood cells only in the presence of ex vivo antigens, while that of patient 2 reacted positively to native ceftriaxone and its ex vivo antigen. In the latter patient, the antibodies appeared to cross-react with native cefotaxime whereas, in the first patient, they weakly cross-reacted only with the ex vivo antigens of cefotaxime and cefpodoxime proxetil. CONCLUSION: Ceftriaxone and/or its trace metabolites may induce life-threatening IHA in children and adults. Serological work-up must include tests to determine the cross-reactivity of ceftriaxone-dependent antibodies to avoid immune haemolysis due to administration of structurally related cephalosporins in affected patients.

Acute Kidney Injury↗
PubMed2000

Immunomagnetic selection of CD34+ cells: factors influencing component purity and yield.

BACKGROUND: In immunomagnetic selection of CD34+ cells from HPC transplants, not all factors that affect yield and purity of CD34+ cells are known. METHODS: Forty-three consecutive procedures of immunomagnetic selection of CD34+ cells from peripheral blood HPCs and bone marrow harvests (autologous harvests, n = 27; allogeneic harvests; n=16) were performed by use of a cell selection system (Isolex 300i, Baxter Immunotherapy). The composition of the starting component and the subsets of CD34+ cells were analyzed for correlation with the yield and purity of the final component. RESULTS: The mean purity of the final components was 84.3 percent (range, 27-99%), and the mean yield was 51.4 percent (range, 9.4-80. 4%). Partial regression analysis showed that, among the factors correlating with purity and/or yield, the RBC volume in the starting fraction had the highest predictive impact on the purity and yield of CD34+ cells, even after the exclusion of procedures using bone marrow harvests as an HPC source (beta coefficient, -0.704; p = 0. 001). CONCLUSION: The use of the Isolex 300i system allows efficient recovery of CD34+ cells in routine selection procedures. The volume of RBCs in the starting component should be minimized to ensure a high yield and purity of the final component.

Antigens, CD34↗
PubMed2000

Vaccination-associated immune hemolytic anemia in two children.

BACKGROUND: Two children in whom acute autoimmune hemolytic anemia (AIHA) developed after vaccination were studied. CASE REPORTS: The children were a 20-month-old girl and a 21-month-old boy. The diagnosis of AIHA was made in accordance with established criteria (hemolysis, positive DAT, and lack of other reasons for the hemolysis). Serologic tests were performed according to standard technique. RESULTS: The girl experienced two attacks of hemolysis. The first episode occurred 2 weeks after oral polio vaccination, and the second episode was observed 7 months later, when she received a simultaneous vaccination against mumps, rubella, and measles. The DAT was strongly positive with anti-C3d. No autoantibodies were detectable in either episode. The boy experienced acute hemolysis a few days after a simultaneous revaccination against diphtheria-pertussis-tetanus, Haemophilus influenzae, hepatitis B, and polio. The DAT using anti-IgG was strongly positive, and the DAT performed with anti-C3d was weakly positive. CONCLUSION: Vaccination-induced AIHA resembles those forms of AIHA related to infectious diseases, and it may occur more frequently than has been reported.

Agglutination Tests↗
PubMed2000

Determination and Successful Transfusion of Anti-Gerbich-Positive Red Blood Cells in a Patient with a Strongly Reactive Anti-Gerbich Antibody.

Background: The clinical relevance of antibodies directed against members of the Gerbich (GE) family of antigens is not invariably clear. Given the scarcity of serologically compatible red blood cells (RBC), various methods may have to be applied to assess the safety of transfusing serologically incompatible RBC. Patient and Methods: The serum of a 57-year-old male Caucasian admitted to hospital for gastrectomy was found to contain a highly reactive anti-GE2 antibody (IgG(1)). In addition to a monocyte monolayer assay, 50 ml of GE2-positive RBC were transfused, and blood samples were taken before and 1 and 24 h after transfusion for flow-cytometric determination of transfused cells. Results: Both tests showed no increased destruction of GE2-positive RBC. The transfusion of 4 units of GE2-positive RBC was well tolerated, and hemoglobin increased adequately. Conclusion: This case may extend the information available not only on antibodies directed against members of the GE family of antigens but also on methods to estimate the survival of transfused RBC. Copyright 2000 S. Karger GmbH, Freiburg

Journal Article↗
PubMed2000

An extended lymphocytotoxicity test for patients treated with lymphocytotoxic antibodies.

BACKGROUND AND OBJECTIVES: After organ transplantation, HLA antibodies (HLA-Ab) stimulated by transplant or transfusion are usually indistinguishable from passive therapeutic lymphocytotoxic antibodies (LyAb), e.g. antilymphocyte globulin (ALG), antithymocyte globulin (ATG) and OKT3, by standard lymphocytotoxicity tests (LCTs). Herein, an extended technique capable of distinguishing between these two types of antibodies is described. MATERIALS AND METHODS: Serum samples from 11 patients who received therapeutic antibodies were screened for HLA-Ab by LCTs. The administered LyAb were murine OKT3 (n = 2), equine ALG (n = 3), rabbit ATG (n = 2), and combinations of ALG and OKT3 (n = 1), ATG and ALG (n = 1), and ATG and OKT3 (n = 2). To discriminate between therapeutically applied antibodies and active HLA alloimmunization, the sera were preincubated with species-specific anti-Fc IgG, thus blocking the therapeutic antibodies. RESULTS: The sera of all patients treated showed strong positive lymphocytotoxic reactions [panel reactive antibodies (PRA) 50-100%]. After incubation with the corresponding Fc antibodies, in 9 of the 11 samples the amount of PRA decreased to the level present before transplantation (0-18%). In the remaining cases, new-onset alloimmunization was detected. CONCLUSION: This extended LCT allows the screening of serum samples for active HLA-Ab even in the presence of therapeutic LyAb.

Adolescent↗
PubMed2000

Detection of germ-cell tumor cells in peripheral blood progenitor cell harvests: impact on clinical outcome.

Our study was conducted to evaluate the impact of tumor cell contamination in peripheral blood progenitor cell (PBPC) harvests on the clinical outcome of patients with germ-cell tumors undergoing high-dose chemotherapy (HDCT) and autologous PBPC reinfusion. Samples of mononuclear cells from progenitor cell harvests of 57 patients with advanced or recurrent germ-cell tumors were retrospectively screened for contaminating tumor cells using immunocytochemical staining for cytokeratin filaments and reverse transcription-PCR (RT-PCR) testing for germ-cell alkaline phosphatase mRNA. The results were correlated to clinical prognostic variables as well as to the overall and event-free survival of these patients. Tumor cell contamination was detected in PBPC harvests of 16 of 57 enrolled patients (28%), and, among these, in 14 of 51 (27%) who underwent HDCT. The presence of contaminating tumor cells as detected by either immunocytochemical staining, RT-PCR, or both was strongly associated with a reduced overall survival (43% versus 71%, P = 0.0037) and event-free survival (0% versus 52%, P = 0.0005) after 1 year. In multivariate analysis, the demonstration of contaminating tumor cells had a higher predictive value for a poor event-free survival than other known prognostic variables. The presence of contaminating tumor cells in PBPC harvests of patients with germ-cell tumors seems to predict a poor overall and event-free survival in patients undergoing HDCT and autologous PBPC reinfusion.

Adult↗
PubMed1999

Do we have a less severe form of Kawasaki disease or is it the gammaglobulin effect?

This study was undertaken to evaluate the incidence of coronary artery aneurysms (CAA) in Kawasaki disease (KD). We reviewed the clinical and echocardiographic findings of 135 children who presented to our center with KD between December 1986 and December 1997. The age of onset ranged between 3months to 13 years (median 2 years). The male to female ratio was 1.54:1. All patients received intravenous Gammaglobulin (IVGG) during the acute stage. The echocardiogram, which was done between 2-3 weeks of the onset of fever, was normal in 106 patients (78.5%). Follow-up studies over a period of 6 months to 1 year remained normal. Minimal right or left coronary artery wall ectasia without dilatation or aneurysm formation was seen in 16 (11.85%). Follow-up of these patients showed disappearance of these changes over 6 weeks to 6 months. One patient (0.74%) had generalised dilatation of all the coronary arteries during the acute stage. This has normalized over a period of 9 months. A total of 10 (7.4%) had CAA during the acute stage. On follow-up of 8 of these patients for an average 3 months to 1.5 years all CAA regressed completely. One patient had residual Giant CAA after 1 year follow-up. One patient with CAA was lost to follow-up. One patient (0.74%) had pericardial effusion and another one (0.74%) had mitral incompetence during the acute stage only, both had no coronary involvement. None of our patients had cardiac failure, arrhythmia, myocardial infarction or death. We conclude that coronary artery changes due to KD are less common and less severe in our patients than those seen in other studies. We speculate that this can be related partly to the early administration of IVGG. The difference in incidence of CAA secondary to KD among different racial groups warrants more detailed genetic studies.

Adolescent↗
PubMed1999

Percutaneous management of renal calculi: experience with percutaneous nephrolithotomy in 60 children.

PURPOSE: We report our experience with percutaneous nephrolithotomy in a pediatric population in which primary as well as recurrent stone episodes are frequent and the need for less invasive procedures is imperative. MATERIALS AND METHODS: Percutaneous nephrolithotomy was performed in 60 children 3 to 13 years old (average age 6), including 44 boys (73.3%) and 16 girls (26.7%). There was a single obstructing renal calculus in 43 patients, while 17 had multiple calculi. The procedure was performed in 1 stage in 49 patients, and it was staged with preliminary nephrostomy in 11 who presented with calculous anuria and elevated serum creatinine. Normal saline was used as an irrigant and perioperatively serum electrolytes were measured to monitor fluid absorption in 18 patients. Stones were extracted intact from 40 patients (66.6%) and ultrasonic lithotripsy was performed in 20 (33.3%). RESULTS: Of the 60 patients 50 (83.3%) were rendered stone-free at 1 session. Incomplete stone clearance at 1 session was due to intraoperative bleeding requiring blood transfusion, extravasation, multiple stones that were inaccessible via 1 tract, displacement of stone fragments into an inaccessible calix and insignificant residual fragments less than 3 mm. in 2 cases each. During followup of 3 months to 6 years (average 1 year) no late complications were noted. CONCLUSIONS: Percutaneous nephrolithotomy is a safe and relatively efficacious mode of managing pediatric renal calculi. Although higher success rates are achieved in adults, caution should be exercised in children, in whom diligent attempts at stone clearance in 1 session may be made at the expense of safety.

Adolescent↗
PubMed1999

Quinine-induced immune thrombocytopenic purpura followed by hemolytic uremic syndrome.

Immune thrombocytopenic purpura (ITP) mediated by quinine-dependent platelet reactive antibodies is well recognized. More recently there have been a number of reports of quinine-induced hemolytic-uremic syndrome (HUS). We describe a patient with quinine-induced immune thrombocytopenia who subsequently developed HUS after re-exposure to a single dose of this drug. To our knowledge, this is the first such case reported. Multiple quinine-dependent antibodies have been characterized in the patient's serum. Initially, quinine-dependent antibodies were directed solely against the platelet glycoprotein complex GPIb/IX. After rechallenge with quinine, there was broadening of quinine-dependent antibody specificities, which were now also directed against the platelet glycoprotein complexes GPIb/IX and GPIIb/IIIa, endothelial cells, and leukocytes. We have shown quinine-dependent antibody-mediated endothelial cell activation, which supports an immunopathogenic role for quinine-dependent antibodies in the causation of this disease.

Antibodies↗
PubMed1999

Fatal immune haemolysis due to a degradation product of ceftriaxone.

A 16-year-old girl who was treated with ceftriaxone developed two intravascular haemolytic attacks that led to acute renal failure and death. The direct antiglobulin test was positive only for C3d, and no ceftriaxone-dependent antibodies were detectable. Her serum reacted strongly positive with red blood cells in the presence of ex vivo antigen related to ceftriaxone (urine samples from patients receiving the drug). This is the first reported case in which the causative antibodies appeared to be stimulated solely by a degradation product of ceftriaxone.

Adolescent↗
PubMed1999

Alterations in expression and in serum activity of dipeptidyl peptidase IV (DPP IV, CD26) in patients with hyporectic eating disorders.

The notion that patients with eating disorders maintain a functional immunosurveillance in spite of severe malnutrition has attracted researchers for years. Dipeptidyl peptidase IV (DPP IV), a serine protease with broad tissue distribution and known activity in serum, operates in the cascade of immune responses. Membrane-bound DPP IV expressed on lymphocytes, also known as the leucocyte antigen CD26, is considered to participate in T-cell activation. We hypothesized that the activity of DPP IV in serum and expression of CD26 in lymphocytes may be altered in patients with eating disorders. Serum DPP IV activity and the number of CD26 (DPP IV)-positive peripheral blood lymphocytes were measured in 34 patients [anorexia nervosa (AN): n = 11, bulimia (B): n = 23] in four consecutive weekly analyses. In addition, the expression of CD25 (interleukin-2 receptor alpha chain) was evaluated to estimate the degree of T-cell activation. The same analyses were carried out in healthy female volunteers (HC, n = 20). CD2-CD26-positive cells were reduced in patients compared with healthy controls [mean 40.2% (AN) and 41.1% (B) versus 47.4% (HC), P < 0.01], while the DPP IV activity in serum was elevated [mean 108.4 U/l (AN) versus 91.1 U/l (B) and 80.3 U/l (HC), P < 0.01]. The potential implications of our observations on, and beyond, immune function are discussed.

Anorexia Nervosa↗
PubMed1999

Demonstration of drug-dependent antibodies in two patients with neutrophenia and successful treatment with granulocyte-colony-stimulating factor.

BACKGROUND: Many drugs have been reported as being capable of inducing immune neutropenia, but the causative drug-dependent antibodies were rarely demonstrated. STUDY DESIGN AND METHODS: This report describes the results of serologic testing and treatment in two children with immune neutropenia related to cefotaxime and metamizole, respectively. Serum samples were tested in the presence and the absence of the drugs using the granulocyte agglutination test (GAT), the granulocyte immunofluorescence test (GIFT), and the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay. RESULTS: The serum of one child contained cefotaxime-dependent antibodies that were detectable by the GAT and the MAIGA assay, but not by the GIFT. The serum of the other child gave positive reactions in the GAT and GIFT due to HLA antibodies and in the MAIGA assay only in the presence of metamizole. While cefotaxime-dependent antibody was directed against CD16, the metamizole antibody was directed against CD11b and CD35. The administration of granulocyte-colony-stimulating factor led to an abrupt increase in circulating neutrophils in both cases. CONCLUSION: The use of more than one technique is necessary for detection of drug-dependent antibodies against neutrophils, and early administration of granulocyte-colony-stimulating factor may result in fewer complications in these patients.

Adolescent↗
PubMed1999

The linkage between Na+ uptake and ammonia excretion in rainbow trout: kinetic analysis, the effects of (NH4)2SO4 and NH4HCO3 infusion and the influence of gill boundary layer pH

The nature of the linkage between between branchial ammonia excretion (JAmm) and unidirectional Na+ influx (JNain) was studied in the freshwater rainbow trout (Oncorhynchus mykiss). Arterial plasma total [ammonia], PNH3 and JAmm were all elevated approximately threefold by intravascular infusion for 24 h with either 70 mmol l-1 (NH4)2SO4 or 140 mmol l-1 NH4HCO3 at a rate of approximately 400 micromol kg-1 h-1. Both treatments markedly stimulated JNain. NH4HCO3 induced metabolic alkalosis in the blood plasma, whereas (NH4)2SO4 caused a slight metabolic acidosis. Experiments with Hepes-buffered water (5 mmol l-1) under control conditions demonstrated that increases in gill boundary layer pH were associated with decreases in both JNain and JAmm. Thus, the stimulation of JNain caused by ammonium loading was not simply a consequence of a Na+-coupled H+ extrusion mechanism activated by internal acidosis or by alkalosis in the gill boundary layer. Indeed, there was no stimulation of net acidic equivalent excretion accompanying NH4HCO3 infusion. Michaelis-Menten kinetic analysis by acute variation of water [Na+] demonstrated that both infusions caused an almost twofold increase in JNamax but no significant change in Km, indicative of an increase in transporter number or internal counterion availability without an alteration in transporter affinity for external Na+. The increase in JNain was larger with (NH4)2SO4 than with NH4HCO3 infusion and in both cases lower than the increase in JAmm. Additional evidence of quantitative uncoupling was seen in the kinetics experiments, in which acute changes in JNain of up to threefold had negligible effects on JAmm under either control or ammonium-loaded conditions. In vitro measurements of branchial Na+/K+-ATPase activity demonstrated no effect of NH4+ concentration over the concentration range observed in vivo in infused fish. Overall, these results are consistent with a dominant role for NH3 diffusion as the normal mechanism of ammonia excretion, but indicate that ammonium loading directly stimulates JNain, perhaps by activation of a non-obligatory Na+/NH4+ exchange rather than by an indirect effect (e.g. Na+-coupled H+ excretion) mediated by altered internal or external acid-base status.

Journal Article↗
PubMed1998

Regulation of ion transport across lamprey (Lampetra fluviatilis) erythrocyte membrane by oxygen tension

We have measured the effects of oxygen tension on the transport of Na+, K+ and Cl- across the erythrocyte membrane of the lamprey Lampetra fluviatilis. The transport of each ion was affected by the oxygen tension of the medium. Hypoxic conditions (PO2 2 kPa) caused an increase in the acidification-induced influx of Na+ via Na+/H+ exchange. The influx of K+ was only slightly affected by the oxygenation of the medium. In contrast, the basal K+ efflux, measured using the radioactive isotope 43K, was markedly reduced by decreasing the oxygen tension of the medium, whereas the K+ flux in hypotonic medium was not affected. Only minor effects of hypoxic conditions on the influx of Cl- were observed in either isotonic or hypotonic conditions (there was a tendency for the isotonic influx to increase) or on the efflux in isotonic conditions. However, deoxygenation caused a marked reduction in the Cl- efflux in hypotonic conditions. The results show that oxygen tension has a marked effect on the pH and volume regulatory transport pathways of lamprey erythrocytes. For K+ and Cl-, the regulation appears to be asymmetric, i.e. influx and efflux are affected differently.

Journal Article↗