Variant von Willebrand's disease type B--revisited

Results of investigations of the factor VIII (FVIII) of a patient with an unusual variant form of von Willebrand's disease (vWD) are presented. A two-peak crossed-immunoelectrophoresis (CIE) pattern was seen when fresh plasma was electrophoresed, but the CIE pattern became normal by incubating the plasma at 37 degree C for more than 72 hr. The two peaks on CIE were separated by cryoprecipitation: the slow-moving peak precipitating and the fast-moving forms of FVIII remaining in the cryosupernate. An additional protein band was seen on multimeric analysis of FVIII. The platelet-rich plasma (PRP) from this patient did not respond to ristocetin, but agglutinated normally in response to botrocetin. Multimeric and CIE analysis of the FVIII post agglutination and 125I-FVIII binding studies to normal formalin-fixed platelets indicated that this patient's FVIII interacted normally with botrocetin but failed to interact with ristocetin. These data strongly suggest that the sites on the FVIII molecule or the multimeric forms involved for ristocetin and botrocetin are different and that the ristocetin reaction is more closely aligned to the physiologic function of FVIII.     

Pretreatment tumor mass, cell kinetics, and prognosis in multiple myeloma

One-hundred fifty patients with multiple (plasma cell) myeloma had pretreatment tumor mass staging, and 79 also had measurement of the pretreatment labeling index (LI%). There were clear differences in survival by pretreatment stage of disease. The pretreatment LI% of bone marrow plasma cells was an independent prognostic factor both in single factor and multivariate regression analyses, including myeloma stage (p less than 0.02). Other important prognostic factors (multivariate) included performance status, serum creatinine, presence of Bence Jones protein, age, and kappa/lambda subtype. A LI% of less than 1% was associated with long survival in each patient group. Patients with benign gammopathy had excellent survival and very low labeling indices. A pretreatment LI% of greater than 3% in high cell mass patients with a high total number of DNA synthesizing cells (S) conferred a very poor prognosis (p = 0.002). This subgroup of patients with high S values also had a high incidence of central nervous system relapse (27%), Bence Jones proteinuria, and elevated serum uric acid levels. We conclude that the pretreatment labeling index provides helpful prognostic information in addition to tumor mass staging.     

Anesthesia and Pulmonary Hypertension

Anesthesia and surgery are associated with significantly increased morbidity and mortality in patients with pulmonary hypertension due mainly to right ventricular failure, arrhythmias, postoperative hypoxemia, and myocardial ischemia. Preoperative risk assessment and successful management of patients with pulmonary hypertension undergoing cardiac surgery involve an understanding of the pathophysiology of the disease, screening of patients at-risk for pulmonary arterial hypertension, analysis of preoperative and operative risk factors, thorough multidisciplinary planning, careful intraoperative management, and early recognition and treatment of postoperative complications. This article will cover each of these aspects with particular focus on the anesthetic approach for non-cardiothoracic surgeries.     

Platelet interactions with fibronectin: divalent cation-independent platelet adhesion to the gelatin-binding domain of fibronectin

Divalent cation-dependent platelet adhesion to fibronectin (FN) is mediated by the integrin receptors alpha 5 beta 1 (GP Ic-IIa) and alpha IIb beta 3 (GP IIb-IIIa), which recognize the RGD (Arg-Gly-Asp) sequence in the cell-binding domain. However, FN can also support divalent cation-independent platelet adhesion. To determine which domain of FN mediates divalent cation-independent adhesion, proteolysis with thermolysin and affinity chromatography were used to isolate the cell-binding, gelatin-binding, and heparin-binding domains of FN. Unactivated and thrombin-activated platelets adhered to intact FN and the 45-Kd gelatin-binding domain in the presence of either Ca2+ or EDTA. Platelet spreading was mediated only by the 105-Kd cell-binding domain and required divalent cations. The heparin-binding domains did not support platelet adhesion. Reduction of intrachain disulfide bonds or removal of carbohydrate side chains on the gelatin-binding domain did not alter the ability to support platelet adhesion. Divalent cation- independent adhesion to the 45-Kd gelatin-binding domain was not inhibited by RGDS (Arg-Gly-Asp-Ser) synthetic peptides or monoclonal antibodies (MoAbs) directed against known platelet receptors. We conclude that platelets can adhere but not spread on the gelatin- binding domain of FN by a novel divalent cation-independent mechanism.     

Neutrophil surface markers in patients with acute leukemia

The presence of complement and Fc receptors on neutrophils from patients with acute leukemia was investigated at different stages of the leukemic process. Both Fc receptors (Fc-H and Fc-R) and one complement receptor (C3d) were normal when patients were studied at diagnosis, in relapse, and in remission. In contrast, the C3b receptor was significantly reduced on te neutrophils at the time of diagnosis, but returned to normal levels when patients entered remission. Variable amounts of C3b activity were observed in patients relapse, with approximately one-half of the patients showing decreased C3b activity. To determine whether the reduction inC3b receptors was specific for patients at diagnosis, three patients were studied at different times during their diseases. Normal receptor levels were detected in these patients during remission, but the C3b receptor was markedly reduced at diagnosis and at relapse.     

High glucocorticoid receptor content of leukemic blasts is a favorable prognostic factor in childhood acute lymphoblastic leukemia

We have previously shown that the number of glucocorticoid receptors (GR) per cell in malignant lymphoblasts from children with newly diagnosed pre-B- and early pre-B-cell acute lymphoblastic leukemia (ALL) has a positive correlation with the probability of successful remission induction (Quddus et al, Cancer Res, 45:6482, 1985). We report now on the long-term outcome for these patients treated on a single protocol with 3 different treatment arms, all of which included glucocorticoid pulses during maintenance therapy. GR were quantitated in leukemic cells from 546 children with ALL at the time of diagnosis. Immunophenotyping studies were performed on all specimens. Prior studies showed that in pre-B- and early pre-B-cell ALL, successful remission induction was associated with a median GR number of 9,900 sites/cell, whereas induction failure was associated with a median receptor number of 4,800 sites/cell. Long-term follow-up of these patients shows an association between higher GR number and improved prognosis. The 5-year event-free survival of 61.0% (SE 2.8%) for patients whose leukemic cells had greater than 8,000 receptors/cell and 47.3% (SE 3.3%) for those with less than 8,000 receptors/cell is significantly different (P < .001). This difference remains significant when adjusted multivariately for blast immunophenotype and clinical risk factors (P < .001) or for treatment type (P < .001). We conclude that GR number greater than 8,000 sites/leukemic cell is a favorable prognostic marker for children with acute lymphocytic leukemia. This finding offers deeper insights into molecular mechanisms of anti- leukemia therapy and suggests that manipulation of steroid receptor number might augment the antitumor response, thus opening new avenues for basic and clinical research.     

Spectrin Tunis (Sp alpha I/78), an elliptocytogenic variant, is due to the CGG----TGG codon change (Arg----Trp) at position 35 of the alpha I domain

Spectrin Tunis (Sp alpha I/78) is an alpha l domain variant that causes asymptomatic elliptocytosis in the heterozygote state. It is manifested by a reduction of spectrin dimer self-association and by the development of a major 78-Kd fragment at the expense of the alpha l 80- Kd fragment upon spectrin-limited digestion. Amino acid sequence analysis, following peptide transfer onto Immobilon membranes, showed that the 78-Kd fragment results from a sensitized cleavage after lysyl residue 10. Using a 13.5-kb genomic alpha-spectrin probe and the Xbal, Pvull, and Mspl polymorphic sites detected with this probe, we concluded that spectrin Tunis is associated with the + - + haplotype (in the above order). Twenty mer oligonucleotides, complementary to genomic segments from introns 2 and 3, respectively, were synthesized. We then performed DNA amplification and sequencing. In the two investigated carriers of spectrin Tunis, we found the C----T base substitution of the codon corresponding to position 35 of the alpha l domain (CGG----TGG; Arg----Trp). The mutation lies in the last part of an alpha helix that extends from residues 9 to 44 of partial repeat alpha 1' and is comparable with helix 3 of full repeats 1 to 5. The modified proteolytic site, located 25 amino acid residues upstream, occurs at the beginning of the helix.     

Isoflurane Pretreatment Ameliorates Postischemic Neurologic Dysfunction and Preserves Hippocampal Ca2+/Calmodulin-dependent Protein Kinase in a Canine Cardiac Arrest Model

Background: Inhalational anesthetics are neuroprotective in rat models of global ischemia. To determine whether isoflurane at a clinically relevant concentration is neuroprotective in a canine model of cardiac arrest, we measured neurologic function and hippocampal Ca2+/calmodulin-dependent protein kinase II (CaMKII) content 20 h after cardiac arrest.

Methods: We tested the neuroprotective effect of 30 min of 1.5% isoflurane exposure before 8 min of global ischemia induced with ventricular fibrillation. Animals were randomized to four groups: control, isoflurane-control, ischemia, and isoflurane-ischemia. After resuscitation and 20 h of intensive care, each animal's neurologic deficit score was determined by two blinded evaluators. The hippocampal content of CaMKII, determined by immunoblotting, was measured by an individual blinded to the treatment groups. CaMKII activity was measured in samples from the cortex, hippocampus, and striatum of animals in each group.

Results: Isoflurane-ischemic animals had a median neurologic deficit score of 22.6% compared with 43.8% for the ischemic animals (P < 0.05). Hippocampal levels of the [beta]-subunit of CaMKII (CaMKII[beta]) were relatively preserved in isoflurane-ischemic animals (68 +/- 4% of control) compared with ischemic animals (48 +/- 2% of control;P < 0.001), although both groups were statistically significantly lower than control (P < 0.001 ischemia vs. control and P < 0.05 isoflurane-ischemia vs. control).