Differential effect of Serratia protease on platelet surface glycoproteins Ib and V

The effect of a zinc metalloprotease from Serratia marcescens on platelet surface glycoproteins (GP) Ib and V was analyzed. Increasing protease treatments caused progressive loss of GP Ib with appearance of the major fragment, glycocalicin, in the supernatant solution. No GP V was detected in the supernatant solution, and protease-pretreated platelets had the same capacity as control platelets to release fragment 1 of GP V in response to thrombin. The Serratia protease- pretreated platelets did show the lag before thrombin-induced dense granule secretion, characteristic of platelets modified by pretreatment with other nonstimulating proteases. Treatment with Serratia protease gives the only demonstrated selective loss of GP Ib without apparent effect on GP V. It suggests that GP V (1) does not depend on GP Ib for its association with platelets and (2) is not the substrate for protease modification of platelet function.     

Peripheral T cell lymphoma: immunologic and cell-kinetic observations associated with morphological progression

Peripheral T cell lymphomas (PTCLs) form a morphologically heterogeneous group of non-Hodgkin's lymphomas that are generally considered to have immunophenotypes associated with mature T cells, usually those of helper T cells. We now describe and correlate the clinical, morphological, immunologic, and cell-kinetic findings based on the evaluation of eight tissue samples obtained at various times from a 13-year-old girl with PTCL. The early morphological expressions of this patient's PTCL were those of diffuse mixed-cell lymphoma and focal large-cell lymphoma (LCL) evolving from the histologic picture of an atypical immune response (AIR). These morphological findings were associated with an immature T cell immunophenotype associated with cortical thymocytes--namely, sheep erythrocyte rosette (sER)+, T11+, Leu-2a+, Leu-3a+, HLA-DR+, OKT6-, OKT9+, OKT10+--and with cell-kinetic findings that showed no evidence of aneuploidy and few cells in S phase. Diffuse pleomorphic LCL developed, which was associated with further dedifferentiation of the neoplastic T cells to the immunophenotype sER-, T11+, Leu-2a-, Leu-3a-, HLA-DR+, OKT6-, OKT9+, OKT10- and with cell-kinetic findings that demonstrated a distinct aneuploid population and a dramatic increase in the percentage of cells in the S phase. The immunophenotype of the PTCL at the time of the patient's death was T11-, Leu-2a-, Leu-3a-, HLA-DR+, OKT6-, OKT9+, OKT10-, an immunophenotype indistinguishable from that of a non-B non-T cell lymphoma. The immunologic findings in this case also suggest that an AIR in some cases may represent a prelymphomatous state or may be a morphological expression of PTCL. These observations indicate that PTCLs may be characterized by rapidly changing clinical, morphological, immunologic, and cell kinetic findings which are best evaluated by multidisciplinary studies.     

Beta 2-integrin and L-selectin are obligatory receptors in neutrophil aggregation [see comments]

We have recently found that antibodies to L-selectin, the homing receptor on neutrophils, are as effective as those to beta 2-integrin at blocking formyl peptide-stimulated aggregation. Therefore, we investigated the requirements for expression of L-selectin and beta 2- integrin on adjacent cells during aggregation. Fluorescence flow cytometry allowed characterization of aggregates on the basis of size and color, as well as antibody binding to these two adhesive molecules. Formyl peptide-stimulated aggregate formation was measured for individual populations fluorescently labeled red (LDS-751) or green (CD44-FITC), and interpopulation red-green cell conjugates. Blocking either the beta 2-integrin or L-selectin adhesive epitope with monoclonal antibody on individual cell populations resulted in an approximately 50% reduction in two-color aggregation as compared with that in unblocked samples. Shedding the L-selectin on a cell population by preincubation with complexes of lipopolysaccharide and its plasma membrane binding protein also decreased aggregation to a control population by approximately 50%. We examined the aggregation of neutrophils from patients genetically deficient in beta 2-integrin and clinically leukocyte adhesion deficient (LAD). LAD adhesion to normal neutrophils was dependent on the expression of L-selectin on LAD cells and beta 2-integrin on normal cells. Thus, the minimum requirement for adhesion between two mixed populations of neutrophils was that one population expressed the beta 2-integrin and the other expressed the L- selectin adhesive epitope.     

Perioperative external ventricular drainage in obstructive hydrocephalus secondary to infratentorial brain tumours

Summary Of 148 patients with infratentorial brain tumours which were operated upon during a 5 year period, 59 patients had associated obstructive hydrocephalus, as evidenced by preoperative CT scan. External ventricular drainage was performed in these cases at time of surgery. CSF drainage was continued in the postoperative period for a mean of 2.3 (± 1.6) days. Only 6 of these 59 patients (10%) required a subsequent indwelling shunt. The infection rate was 10% and the total mortality was 8%. Perioperative ventricular drainage during and following the removal of posterior fossa tumours causing hydrocephalus provides an effective alternative to the preoperative placement of an indwelling shunt. Problems of shunt dysfunction, tumour seeding and upward herniation are thereby avoided. Post-operative ICP monitoring and drainage of blood and debris laden CSF is performed, increasing the safety of the postoperative period and possibly reducing the incidence of aspetic meningitis and post-operative shunt requirement.     

Juvenile amyopathic dermatomyositis

We report a 15-year-old girl with a 10-year-old history of typical skin features of dermatomyositis (DM) without evidence of muscle involvement. Amyopathic dermatomyositis(ADM) is defined by the presence of biopsy confirmed classic cutaneous findings of dermatomyositis in the absence of any clinical or laboratory signs of muscle disease for at least 2 years after onset of skin pathology. To exclude muscle involvement muscle enzymes should be normal; moreover additional use of magnetic resonance imaging and muscle ultrasound is currently being proposed. It is as yet undetermined. whether early aggressive immunosuppressive treatment of ADM might prevent the development of myositis at a later date or influence the course of the skin disease. In a paediatric patient with ADM we advocate a more expectant attitude with careful and regular monitoring for possible development of muscle disease.     

Relapsing eosinophilic perimyositis

Relapsing eosinophilic perimyositis is a rare entity. Only 11 cases have been reported in the literature. We describe a patient with relapsing myopathy, peripheral blood eosinophilia and cutaneous manifestations, who had histopathological features of eosinophilic perimysial inflammation. His disease responded to moderate doses of glucocorticosteroids, and pursued an apparently benign course. Serum levels of eosinophilic cationic protein correlate with disease activity, and may be helpful in monitoring treatment. The features of this case are compared with those of other hypereosinophilic syndromes. It appears to be part of the spectrum of eosinophilic myositis.