Severe thrombocytopenia in an acquired immunodeficiency syndrome patient associated with pentamidine-dependent antibodies specific for glycoprotein IIb/IIIa

Severe thrombocytopenia developed in a patient with acquired immunodeficiency syndrome during treatment with intravenous pentamidine for Pneumocystis carinii pneumonia. The patient's bone marrow contained adequate numbers of megakaryocytes, suggesting peripheral platelet destruction. Platelet counts ranged between less than 3 and 20 x 10(9)/L for 2 weeks despite cessation of pentamidine, platelet transfusions, high-dose intravenous IgG, and 2 mg/kg/d prednisone. Thereafter, the platelet count increased to prepentamidine levels (95 x 10(9)/L0, permitting rapid withdrawal of steroids. Testing by immunofluorescence disclosed a high-titer, pentamidine-dependent IgG antibody in the patient's acute-phase serum that almost entirely disappeared by the time the patient's platelet count returned to baseline levels. This antibody reacted only with platelet glycoprotein (GP) IIb/IIIa as shown by antigen-capture enzyme-linked immunosorbent assay using monoclonal antibodies specific for various GPs, and was absorbable by normal, but not by GPIIb/IIIa-deficient platelets (from a patient with Glanzmann's thrombasthenia). The pentamidine-dependent antibody could not be demonstrated by immunoprecipitation using the patient's serum and 125I-labeled normal platelets, although a separate pentamidine-independent antibody was detected by this method. This latter antibody reacted with two GPs having molecular weights consistent with GPIIb/IIIa, and was present in postrecovery as well as acute-phase sera. However, only the pentamidine-dependent antibody was temporally associated with the severe thrombocytopenia. Therefore, we believe that these studies demonstrate, for the first time, that intravenous pentamidine therapy can provoke formation of drug-dependent antibodies that induce immunologic thrombocytopenia.     

Human acute myeloid leukemia cells bind to bone marrow stroma via a combination of beta-1 and beta-2 integrin mechanisms

Acute myeloid leukemia (AML) cells respond to exogenous stimulation from myeloid growth factors that may be secreted by cells of the bone marrow (BM) stroma and retained by glycosaminoglycans in the extracellular matrix. We have analyzed the capacity of malignant cells from patients with AML to maintain close proximity to sites of growth factor production and retention by binding to BM stromal elements, including fibroblasts and extracellular matrix proteins. Leukemic cells from all cases of AML adhered to BM fibroblast (BMF) monolayers (mean +/- standard error [SE] percentage binding, 30.9% +/- 2.5%; n = 23) and to fibronectin and laminin (mean +/- SE percentage binding, 28.0% +/- 4.1% [n = 11] and 21.5% +/- 2.3% [n = 8], respectively). Binding to bovine and human collagen type 1, vitronectin, hyaluronic acid, and albumin was minimal. Analysis of binding mechanisms indicated that very late antigen-4 (VLA-4) and VLA-5 were responsible for AML cell binding to fibronectin. Binding to laminin could be inhibited by antibody to the alpha chain of VLA-6. In contrast, AML cell adhesion to BMF monolayers was not impaired by blocking antibodies to either beta 1 or beta 2 integrins used alone, although the combination of anti-CD11/CD18 and anti-VLA-4 inhibited binding in more than 50% of cases. When anti- VLA-5 was added in these cases, mean +/- SE inhibition of binding of 45.5% +/- 9.1% (P < .001) was observed. Binding of AML cells to extracellular matrix proteins fibronectin and laminin is predominantly beta 1-integrin-dependent, but AML cell adhesion to BMF relies on the simultaneous involvement of beta 1 and beta 2 integrins as well as other currently unrecognized ligands.     

Predictability of the t(1;19)(q23;p13) from surface antigen phenotype: implications for screening cases of childhood acute lymphoblastic leukemia for molecular analysis: a Pediatric Oncology Group study

The t(1;19)(q23;p13) translocation occurs in approximately 5% of B- precursor acute lymphoblastic leukemias (ALLs) occurring in children. Its presence has been associated with a poor prognosis, which may be overcome with more intensive therapy. Although leukemic cells from cases of t(1;19)-ALL frequently express cytoplasmic mu heavy chains, their complete antigenic profile remains undefined. Among 697 consecutive cases of B-precursor ALL with complete phenotypic studies using a panel of monoclonal antibodies, 22 cases were found to carry the t(1;19). Twenty of 22 cases had an identical, complex phenotype characterized by homogeneous expression of CD19, CD10, and CD9; complete absence of CD34; and at least partial absence of CD20. Overall, this phenotype was seen in only 8.0% (56 of 697) of childhood B-precursor ALL. One of the two remaining t(1;19)-carrying cases conformed to this phenotype, but was lacking data for CD9. The other case differed by virtue of expression of CD34 and was also hyperdiploid with 55 chromosomes. Molecular studies showed E2A-PBX1 abnormalities in all examined cases (12 of 12) with the t(1;19), including the case lacking CD9 data. In contrast, no E2A-PBX1 abnormalities were detected in the sole t(1;19)-ALL with CD34 expression. Seventeen cases with the characteristic phenotype and uninformative cytogenetics were also molecularly analyzed and 5 of 17 (including 4 of 8 with unsatisfactory cytogenetics and 1 of 9 with a normal karyotype) contained E2A gene rearrangements and E2A-PBX1 fusion mRNAs. Our results show that all cases of t(1;19)-ALL with concomitant E2A-PBX1 fusion invariably express a characteristic but uncommon profile of surface antigens. These observations suggest that selective molecular analysis of a small subset of patients (those with uninformative cytogenetics and the characteristic phenotype) can identify a significant number of additional cases of ALL with E2A-PBX1 fusion that might benefit from more intensive therapy.     

Clinical presentation and outcome of tuberculosis patients infected by M. africanum versus M. tuberculosis.

SETTING: A tuberculosis (TB) case contact study in the Gambia. OBJECTIVE: To test whether Mycobacterium africanum, which has lost around 68 kb compared with M. tuberculosis sensu stricto, causes less severe TB disease. DESIGN: We genotyped mycobacterial isolates and compared clinical and radiological characteristics as well as outcome data of M. africanum-infected TB patients with those infected with M. tuberculosis. RESULTS: Of 317 index cases, 301 had a mycobacterial isolate available, 290 of which had an interpretable spoligotype pattern. Of these, 110 isolates (38%) were M. africanum and 180 (62%) were M. tuberculosis. M. africanum cases had lower body mass indices (17 vs. 17.45 for M. tuberculosis-infected patients, P = 0.029) and their radiographic disease was more extensive (96% vs. 89% had at least moderately severe radiographic changes, P = 0.031). Outcome on treatment was similar (2.8% of human immunodeficiency virus [HIV] negative M. africanum patients died on treatment vs. 3.0% of M. tuberculosis patients, P = 0.95). CONCLUSION: M. africanum causes sputum smear-positive tuberculosis disease that is at least as severe as that caused by M. tuberculosis sensu stricto. Further clinical comparisons may be helpful in smear-negative patients and HIV-TB co-infected patients, and to identify whether there is any difference in time to develop disease.     

New Pharmacological Strategies in Chronic Heart Failure

Summary Diuretics, ACE inhibitors and betablockers form the cornerstone of pharmacological treatment of chronic heart failure (CHF), while angiotensin receptor blockers are gaining ground. However, despite optimal treatment CHF remains a syndrome with poor prognosis. For this reason, a large number of new agents have been developed as add-on treatment over the last few years. Vasopeptidase inhibitors, moxonidine, endothelin antagonists, vasopressin antagonists, and selective aldosterone antagonists, are some of the new agents that were designed to interfere with different neurohormonal pathways. Immunomodulating agents, growth hormone, caspase inhibitors, adrenomedullin, and erythropoietin have different modes of action, which in general are less understood. Although most of the agents exhibited efficacy in preclinical trials, the clinical results have not always been similarly positive. The results of trials involving vasopeptidase inhibitors, endothelin antagonists, immunomodulating agents, and growth hormone have been disappointing. Other compounds like caspase inhibitors, adrenomedullin, and vasopressin antagonists are still at the early stages of development. Currently, the two most promising agents seem to be erythropoietin and the selective aldosterone receptor blocker eplerenone. In the present article an overview of new pharmacological developments for CHF is given, and the clinical value of these developments is discussed.     

Preventive measures in infancy to reduce under-five mortality: a case–control study in The Gambia

Objective  To investigate the relationship between child mortality and common preventive interventions: vaccination, trained birthing attendants, tetanus toxoid during pregnancy, breastfeeding and vitamin A supplementation.
Methods  Case–control study in a population under demographic surveillance. Cases ( n  = 141) were children under five who died. Each was age and sex-matched to five controls ( n  = 705). Information was gathered by interviewing primary caregivers.
Results  All but one of the interventions – whether the mother had received tetanus toxoid during pregnancy – were protective against child mortality after multivariate analysis. Having a trained person assisting at child birth (OR 0.2 95% CI 0.1–0.4), receiving all vaccinations by 9 months of age (OR 0.1; 95% CI 0.01–0.3), being breastfed for more than 12 months (Children breastfed between 13 and 24 months OR 0.1 95% CI 0.03–0.3, more than 25 months OR 0.1 95% CI 0.01–0.5) and receiving vitamin A supplementation at or after 6 months of age (OR 0.05; 95% CI 0.01–0.2) were protective against child death.
Conclusions  This study confirms the value of at least four available interventions in the prevention of under-five death in The Gambia. It is now important to identify those who are not receiving them and why, and to intervene to improve coverage across the population.     

Dyspepsia and Helicobacter pylori in Japanese employees with and without ulcer history

In a Dutch working population, the apparent association between dyspeptic symptoms and Helicobacter pylori infection was found to be entirely due to subjects with an ulcer history. In general populations with a much higher prevalence of H. pylori infection and peptic ulcer disease, such as in Japan, the relationship between dyspepsia and H. pylori has yet to be clarified. A questionnaire on ulcer history and dyspeptic symptoms during the preceding 3 month period was obtained from apparently healthy Japanese employees who underwent a periodic medical examination. In addition, serum samples were analysed for anti-H. pylori IgG antibodies. A total of 196 men and 35 women, aged 23–71 years, participated in the study. Seven women (20%) and 49 men (25%) had a diagnosis of peptic ulcer disease. Among 41 subjects with verified duodenal (26) and/or gastric (17) ulcer, 95% were H. pylori positive while 32% had had frequent dyspeptic symptoms in the 3 months prior to the study (29% of the 35 men and 50% of the 6 women). Among the 147 men and 28 women without an ulcer history, the 3 month period prevalence of frequent dyspepsia was 14 and 32%, respectively. The rate of H. pylori positivity was 80% in non-ulcer dyspeptics and 68% in all other non-ulcer subjects (95% confidence intervals: 61–92 and 61–76%, respectively). Significant differences in symptoms between H. pylori positive and negative subjects could not be detected, neither in the whole population nor in the non-ulcer group. In conclusion, in this Japanese working population, no association was found between dyspeptic symptoms and H. pylori infection, irrespective of the inclusion of subjects with a peptic ulcer history.     

Fetal hemoglobin levels and beta s globin haplotypes in an Indian populations with sickle cell disease

To further explore the cause for variation in hemoglobin F (Hb F) levels in sickle cell disease, the beta globin restriction-fragment length polymorphism haplotypes were determined in a total of 303 (126 SS, 141 AS, 17 S beta degrees, 7 A beta, degrees and 12 AA) Indians from the state of Orissa. The beta s globin gene was found to be linked almost exclusively to a beta S haplotype ( -++-), which is also common in Saudi Arabian patients from the Eastern Province (referred to as the Asian beta s haplotype). By contrast, the majority of beta A and beta degree thalassemia globin genes are linked to haplotypes common in all European and Asian populations (+-----[+/-]; --++-++). Family studies showed that there is a genetic factor elevating Hb F levels dominantly in homozygotes (SS). This factor appears to be related to the Asian beta s globin haplotype, and a mechanism for its action is discussed. There is also a high prevalence of an independent Swiss type hereditary persistence of fetal hemoglobin (HPFH) determinant active in both the sickle cell trait and in sickle cell disease.     

ADP causes subsecond changes in protein phosphorylation of platelets

We developed a general quenched-flow approach to study platelet function as early as 0.3 seconds after stimulation. Phosphorylation of 20- and 47-kiloDalton (kD) proteins was analyzed during the first 5 seconds of platelet response to ADP from 0.5 to 10.0 mumol/L and compared with the progress of aggregation. The onset time for aggregation and phosphorylation of both proteins was less than 1 second; 20-K phosphorylation was increased greater than 200% and 47-K phosphorylation was increased 50%. The ADP sensitivity of 20-K phosphorylation was greater than that of 47-K phosphorylation (P less than .025), and of that of aggregation (P less than .01), with Ka values of 0.7, 1.0, and 1.2 mumol/L of ADP, respectively. The cyclooxygenase inhibitor indomethacin had no effect on aggregation, but inhibited both phosphorylations. Its inhibition of 20-K phosphorylation was greater than that of 47-K phosphorylation. Platelet activation by ADP thus induced biochemical changes well before 1 second. The quenched- flow approach may help to reveal relationships between phospholipase activation, calcium fluxes, and protein phosphorylation during these early periods of platelet activation.     

3 alpha-androstanediol glucuronide in virilizing congenital adrenal hyperplasia: a useful serum metabolic marker of integrated adrenal androgen secretion

To determine whether serum 3 alpha-androstanediol glucuronide (3AG) reflects the overall effect of integrated adrenal androgen secretion in the virilizing form of congenital adrenal hyperplasia (CVAH), circadian levels (0800, 1200, 1600, and 2000 h) of serum 3AG and 17-hydroxyprogesterone (17OHP) or 11-deoxycortisol (S), androstenedione (A), testosterone (T), and 24-h urinary 17-ketosteroids (17KS) were examined in seven patients (pts) with classical 21-hydroxylase deficiency (21OHD) and one pt with classical 11 beta-hydroxylase deficiency (11 beta OHD). Hormonal studies were conducted during the second day of dexamethasone (Dex) administration (2 mg/day). In five poorly controlled CVAH pts, including the 11 beta OHD pt, highly elevated baseline morning (AM) serum 17OHP or S as well as A levels, and elevated AM T levels in three pts decreased markedly in the evening (PM), while elevated serum 3AG showed no significant circadian changes; 17KS levels were markedly elevated for age. During Dex, moderately or slightly elevated AM 17OHP, A, or T in two to four pts with 21OHD decreased to the normal range in the PM. In the pt with 11 beta OHD, S, A, and T levels were suppressed. 3AG levels were modestly elevated or normal, without circadian changes, in these pts; 17KS levels were elevated or normal. In two other 21OHD pts, modestly elevated AM baseline 17OHP and A levels decreased in the PM; elevated AM T decreased in one pt in the PM; modestly elevated 3AG levels showed no circadian changes; 17KS levels were modestly elevated. During Dex, normal or slightly elevated serum steroids and 17KS levels were associated with normal or high normal 3AG levels without circadian changes. In one postpubertal female with 21OHD, modestly elevated AM baseline 17OHP levels decreased at 2000 h; normal A and T levels throughout the day and low normal 17KS were associated with slightly low 3AG levels, without circadian variation. During Dex treatment, normal 17OHP, A, T, and low 17KS levels were associated with low 3AG levels without circadian variation. In all pts as a group, an excellent correlation (r = 0.9) was found between either 0800 h or mean, or 2000 h serum 3AG levels and 17KS. In addition, AM and PM serum 3AG levels in five normal women were similar. We conclude that the high correlation between serum 3AG and urinary 17KS and the absence of a significant circadian variation in 3AG indicate that serum 3AG, regardless of sample time, is a useful metabolic index of integrated adrenal androgen secretion in CVAH.