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Biomedical subjects

B W Baron

Publications and source records attributed to B W Baron.

At least 19 recordsLinked to original sources
PubMed2001

Presurgical plasma exchange for severe factor V deficiency.

We report two patients with severe congenital factor V deficiency, one of whom also had a factor V inhibitor, who required correction of their coagulopathy prior to surgical procedures. They underwent plasma exchange (PE) with fresh frozen plasma or solvent/detergent treated plasma (S/DP), with achievement of factor V levels satisfactory for hemostasis for their procedures. PE makes it possible to raise factor levels quickly and sufficiently without volume overload. In addition, transient reduction of inhibitor titers by PE may improve the level of correction achievable during the perioperative period. The advent of S/DP promises to provide an added increment of safety in patients exposed to significant volumes of plasma during PE.

Adult↗
PubMed2001

Four patients with both thrombotic thrombocytopenic purpura and autoimmune thrombocytopenic purpura: the concept of a mixed immune thrombocytopenia syndrome and indications for plasma exchange.

Autoimmune thrombocytopenic purpura (ATP) and thrombotic thrombocytopenic purpura (TTP) are each well recognized clinical syndromes which may appear as single episodes or may have chronic relapsing courses. We present four patients negative for human immunodeficiency virus (HIV) infection who appear to have both diagnoses with either concomitant or intermingled episodes, and we review seven additional patients reported in the literature with similar features. All four of our patients are female, two have underlying connective tissue disorders, and their ATP processes came to our attention because of incomplete response of the platelet count to plasma exchange therapy (PEX) during a TTP phase (Cases 1 and 2) or development of thrombocytopenia in the absence of microangiopathy on the background of prior typical TTP episodes (Cases 3 and 4). Recognition of the ATP diagnosis in each case resulted in discontinuation of PEX (Cases 1 and 2) or not instituting PEX (Cases 3 and 4). In each instance, a satisfactory rise in platelet count followed treatment for ATP. Based upon this experience, we conclude that some individuals may have a mixed immune thrombocytopenia syndrome; careful analysis of the mechanism of thrombocytopenia, especially in recurrent episodes and in patients who respond incompletely to PEX for TTP, is important when deciding whether to initiate or continue PEX, or to consider therapies appropriate for other mechanisms of thrombocytopenia.

Adult↗
PubMed2001

Ceftizoxime-induced hemolysis secondary to combined drug adsorption and immune-complex mechanisms.

BACKGROUND: Immune hemolytic anemia has been associated with the administration of various antibiotics, including cephalosporins. Presented here is a patient who developed severe acute hemolysis while receiving ceftizoxime (Ceftizox, Fujisawa USA), a third-generation cephalosporin. This is the fourth reported case of hemolysis in association with ceftizoxime. In the previous cases, ceftizoxime was shown to induce hemolysis by the immune-complex mechanism. However, in one of those reports, the concentration of drug used to treat the target RBCs in vitro may not have been optimal. CASE REPORT: The patient's antemortem blood samples were analyzed retrospectively for drug-dependent antibodies by the drug-adsorption and immune-complex methods. Antibody class and titer were evaluated. RESULTS: The patient's sample agglutinated RBCs coated with ceftizoxime as well as uncoated RBCs in the presence of ceftizoxime. The antibodies to ceftizoxime were IgM and IgG. CONCLUSION: This is the first report on both the immune-complex and drug-adsorption mechanisms of ceftizoxime-induced hemolysis. The differential diagnosis of a falling Hct in a patient receiving antibiotics should include drug-related hemolysis; once this diagnosis is considered, management includes the appropriate serologic workup, immediate cessation of the implicated drugs, and possible transfusion support.

Adsorption↗
PubMed2000

Study of three patients with thrombotic thrombocytopenic purpura exchanged with solvent/detergent-treated plasma: is its decreased protein S activity clinically related to their development of deep venous thromboses?

Solvent/detergent treated plasma (S/DP) has reduced protein S activity (about 0.5 units/mL) as compared with fresh frozen plasma (FFP). When used as replacement fluid for repetitive therapeutic plasma exchange (PEX), e.g., in patients with thrombotic thrombocytopenic purpura (TTP), S/DP could lead to lowered protein S levels and, possibly, risk of hypercoagulable complications. We describe three patients with TTP who had low functional protein S (FPS) levels during PEX for TTP. Each developed one or more deep vein thromboses (DVTs) while receiving 100% S/DP or 50% S/DP and 50% cryosupernatant plasma (CSP) as replacement fluid. FPS levels rose when 100% CSP was substituted for S/DP. Our observations suggest that use of S/DP alone or in 50% combination with CSP as replacement fluid in PEX for TTP may lead to difficulty in maintaining safe FPS levels. Determination of risk of resulting clinically significant thrombotic events requires further study.

Adult↗
PubMed2000

Significant ABO hemolytic disease of the newborn in a group B infant with a group A2 mother.

ABO hemolytic disease of the newborn (HDN) occurs almost exclusively in infants of blood group A or B who are born to group O mothers because IgG anti-A or -B occurs more commonly in group O than in group A or B individuals. We report a case in which clinically significant ABO-HDN occurred in a group B neonate from anti-B of a group A2 mother. The IgG anti-B titer was much higher (256) than that found in a group A1 mother/infant control group (</= 32). The maternal antibody screen was negative and antibodies to low-frequency antigens were not detected. Therefore, when evaluating unexplained HDN in a group B newborn of a group A mother, it may be relevant to determine the subgroup of the mother. As presented here, anti-B from a group A2 mother may, on occasion, be responsible for HDN.

Journal Article↗
PubMed1999

Therapeutic plasma exchange for the acute management of the catastrophic antiphospholipid syndrome: beta(2)-glycoprotein I antibodies as a marker of response to therapy.

We describe two patients with the catastrophic antiphospholipid syndrome associated with elevation of beta(2)-glycoprotein I antibodies and fulminant thrombotic diatheses. Both patients were treated with therapeutic plasma exchange (TPE), which resulted in a marked decrease in antibody titer accompanied by an improved clinical outcome in one patient (IgG antibody). In the second patient, the outcome was poor despite TPE (IgA antibody). There were no significant complications of TPE in either case. Because of the fulminant nature of the catastrophic antiphospholipid syndrome, we conclude that a trial of TPE is warranted for the acute management. Further studies are needed to clarify which patients may benefit from this treatment.

Amputation, Surgical↗
PubMed1999

First two cases of immune hemolytic anemia associated with ceftizoxime.

BACKGROUND: Second- and third-generation cephalosporins have been associated with immune-mediated hemolytic reactions. This report discusses two patients who developed clinically significant extravascular hemolysis while receiving the third-generation cephalosporin ceftizoxime (Ceftizox). This is believed to be the first time hemolysis has been described in patients receiving this drug. STUDY DESIGN AND METHODS: Immunologic workup of drug-dependent antibodies was performed on blood samples using drug-coated and immune complex methodologies. Antibody classes and titers were analyzed. RESULTS: Both the patients' sera contained anti-ceftizoxime that reacted with red cells only when ceftizoxime was added to the sera ("immune complex" method). The patients recovered without complications following discontinuation of the drug. Each patient had IgM and IgG drug-dependent antibodies. The drug-induced antibodies from each patient cross-reacted with cefotaxime, which is structurally similar to ceftizoxime, but cross-reacted either weakly or not at all with ceftriaxone, which has a more complex side chain. CONCLUSION: This report describes the first cases of immune hemolytic anemia associated with ceftizoxime. In drug-induced hemolytic reactions, prompt recognition and discontinuation of the drug may be important factors in reducing the chance of serious sequelae.

Adult↗
PubMed1997

BCL6 can repress transcription from the human immunodeficiency virus type I promoter/enhancer region.

The gene BCL6 encodes a zinc finger protein with similarities to transcription factors. We previously reported that a number of viral genomes, including human immunodeficiency virus type I (HIV-1), contain sequences which are similar to the BCL6 DNA-binding consensus in their promoter regions. Electrophoretic mobility shift assays showed that the full-length BCL6 protein extracted from transfected COS cells and a bacterially expressed truncated protein containing the BCL6 zinc fingers can bind specifically to DNA from the U3 promoter/enhancer region of HIV-1. Transient transfections were performed to analyze the effects of the BCL6 protein on luciferase expression driven by the HIV-1 long terminal repeat (LTR) sequences. Full-length BCL6 significantly repressed luciferase activity compared with multiple controls. We conclude that the BCL6 protein can bind to the HIV-1 promoter-enhancer region and contains a domain upstream of its zinc fingers that can repress transcription from the HIV-1 LTR.

Animals↗
PubMed1995

BCL6 encodes a sequence-specific DNA-binding protein.

Chromosomal rearrangements of BCL6 are commonly associated with diffuse large-cell lymphomas. We set out to determine the DNA-binding site of a glutathione-S-transferase fusion protein containing the BCL6 zinc finger region by employing cyclic amplification and selection of targets (CASTing). From oligonucleotides containing 16 central random bases, sequences binding to the protein on glutathione-coated beads were repeatedly selected and amplified by polymerase chain reaction (PCR). The binding sites were cloned and sequenced. A consensus, TTTNNNGNNATNCTTT, was obtained. Protein binding studies of double-stranded oligomers containing point mutations within the 3' CTTT confirmed the binding specificity of this part of the consensus. In addition, evidence indicated that some of the base pairs held constant in the oligonucleotides used for CASTing also contributed to binding.

Base Sequence↗
PubMed1995

Severe hypercalcemia following neonatal liver transplantation.

A 3-week-old infant with liver failure underwent an orthotopic liver transplant. Following a prolonged second surgical procedure in which he received massive amounts of blood products, his serum calcium was 31.3. mg/dl (7.8 mmol/l). This patient represents a case of severe hypercalcemia secondary to intraoperative calcium infusions given in an effort to overcome infusion-related citrate toxicity in a neonate with hepatic dysfunction.

Anticoagulants↗
PubMed1994

Hematuria in sickle cell anemia--not always benign: evidence for excess frequency of sickle cell anemia in African Americans with renal cell carcinoma.

Between 1952 and 1992, we identified 117 African Americans with renal cell carcinoma (RCC) at the University of Chicago. Three of these had sickle cell disease (SS) and 11 had presumed sickle trait (AS). Based on genotype frequencies, these represented a 16.7-fold excess of SS patients (p < 0.0001), but the incidence of AS patients was as expected. In addition, the median age for the SS patients at presentation with RCC (36 years) was significantly less (p = 0.04) than for the AS patients (55 years). We have found no prior reports of SS in RCC patients and suggest that chronic renal injury from sickling and possible immunosuppressive effects of multiple red cell transfusions may be risk factors. We also suggest the need to be aware of the possibility of RCC in SS patients who may have hematuria solely related to sickling.

Adult↗
PubMed1993

Combined plateletpheresis and cytotoxic chemotherapy for symptomatic thrombocytosis in myeloproliferative disorders.

BACKGROUND: Patients with myeloproliferative disorders (MPD) may have symptomatic thrombocytosis develop that requires prompt and sustained lowering of platelet counts to avert serious thrombotic or hemorrhagic sequelae. METHODS: The authors retrospectively studied the short- and long-term effects of plateletpheresis combined with three different chemotherapy regimens (busulfan, hydroxyurea, or busulfan/hydroxyurea) in 30 patients with MPD with symptomatic thrombocytosis. RESULTS: Twenty-nine patients entered first remission (FR) with initial treatment. The average number of plateletphereses to FR was three (standard deviation [SD], +/- 3). Average total dose of busulfan (216 mg) and time to FR (1.6 months) were less than for previously reported patients treated without plateletphereses. Addition of hydroxyurea to busulfan decreased the number of plateletpheresis needed (P = 0.02) but did not additionally reduce the amount of busulfan needed or the time to FR. The shortest time to FR was in the hydroxyurea group (mean, 0.6 +/- 0.3 months), but unmaintained remission could be achieved only in the busulfan-treated groups. With median follow-up of 68 months, median survival was 53 months for the busulfan group, 55 months for the hydroxyurea group, and was undefined with no deaths for the busulfan/hydroxyurea group. Neither fatal complications of recurrent symptomatic thrombocytosis nor development of acute leukemia has occurred, except for progression to blast crisis in two patients with chronic myelogenous leukemia. CONCLUSION: Combined plateletpheresis and chemotherapy is a rapidly effective initial treatment for patients with MPD with symptomatic thrombocytosis. With maintenance therapy or prompt treatment at relapse of disease, prolonged good quality survival can be expected.

Adult↗
PubMed1993

Identification of the gene associated with the recurring chromosomal translocations t(3;14)(q27;q32) and t(3;22)(q27;q11) in B-cell lymphomas.

Chromosomal translocations involving chromosome 3, band q27, are among the most common rearrangements in B-cell non-Hodgkin lymphoma. From a bacteriophage lambda library prepared from a lymphoma characterized by a t(3;14)(q27;q32), genomic clones were isolated using a probe from the immunoglobulin heavy chain locus (IGH) joining region. In addition to clones containing an apparently normal IGH rearrangement, others were found to contain one of the translocation breakpoint junctions. Normal chromosome 3 sequences and the reciprocal breakpoint junction were subsequently isolated. DNA probes on each side of the chromosome 3 breakpoint hybridized at high stringency to the DNA of various mammalian species, demonstrating evolutionary conservation. One such probe from the presumptive der(3) chromosome detected an 11-kilobase transcript when hybridized to RNA of B- and T-cell lines. A probe made from partial cDNA clones isolated from a T-cell line hybridized with genomic DNA from both sides of the chromosome 3 breakpoint, indicating that the t(3;14) is associated with a break within the gene on chromosome 3. In situ chromosomal hybridization revealed that the same gene is involved in the t(3;22)(q27;q11). Preliminary nucleotide sequencing shows no identity of the cDNA to gene sequences in available data banks. We propose the name BCL6 (B-cell lymphoma 6) for this gene, since it is likely to play a role in the pathogenesis of certain B-cell lymphomas.

Animals↗
PubMed1993

Effect of coarctation on matrix content of experimental aortic atherosclerosis: relation to location, plaque size and blood pressure.

Cynomolgus monkeys were fed an atherogenic diet for 6 months following surgically produced high-grade (n = 10) or mild (n = 16) mid-thoracic aortic coarctation. A diet-control (DC) group (n = 13) was fed the diet without coarctation. High-grade coarctation (HGC) resulted in 74.1% +/- 8.3% stenosis by aortography prior to sacrifice and was associated with systolic brachial blood pressures of 143.3 +/- 26.0 mmHg and gradients across the stenoses of 36.8 +/- 23.6 mmHg. Mild coarctation (MC) resulted in stenoses of 50.9% +/- 12.9%, brachial systolic pressures of 119.4 +/- 25.7 and gradients of 12.5 +/- 15.2 mm Hg (P < 0.01, P = 0.03 and P < 0.005, respectively, compared with HGC). When total plaque cross-sectional area exceeded 0.8 mm2, the entire arterial circumference was usually involved. HGC resulted in complete sparing or minimal plaque formation in sections distal to the stenoses compared with proximal sections (P < 0.001). There were no significant differences between MC and DC animals in plaque location or size. Matrix content increased with plaque area regardless of degree of stenosis or sampling level (P < 0.01), but lesions with more than 75% matrix content were more numerous in distal than in proximal sections despite their smaller size. The number of plaques with greater than 75% matrix content was increased proximal to HGC (P < 0.04). Thus, distal location and plaque size were independent determinants of plaque matrix content and matrix content was increased proximal to HGC regardless of plaque size. Attempts to evaluate effects of various regimens and interventions on plaque composition need to take location and plaque size, as well as blood pressure differences, into account.

Animals↗
PubMed1990

Unique anomalies in cephalothoracopagus janiceps conjoined twins with implications for multiple mechanisms in the abnormal embryogenesis.

The anatomic features of female conjoined twins with the Janiceps type of cephalothoracopagus are described. Abnormalities included bilateral clefts of the alveolar arches, shared rudimentary mandible, high, arched clavicles, multiple rib deformities, single shared foregut and small intestine, absent large intestines, omphalocele, multicystic kidneys, hypoplastic lungs, interconnected aortas and neck vessels, single ovary with elongated uterus in each twin, displaced labia, abnormal segmentation of the vertebrae, spinal dysraphism, diastasis of the symphysis pubis, malrotated lower extremity, bilateral posterior dislocation of the hips, and club feet. There were two hearts with internal anomalies. Both spinal cords had a myelocele in the lumbar region. The abnormalities noted in previous reports of conjoined twins of this type are reviewed and compared. We propose that factors associated with conjoining, dysgenetic (developmental) defects, and deformations resulting from crowding in utero all may have been important in the abnormal development in this case.

Digestive System Abnormalities↗