Growth hormone release after glucagon as a reliable test of growth hormone assessment in adults

OBJECTIVE: To investigate the GH response to glucagon in adult patients with GH deficiency and in controls compared with the GH response to the insulin tolerance test (ITT) in patients with GH deficiency and to determine whether the use of glucagon results in a diagnostic utility test. PATIENTS AND DESIGN: Seventy-three patients with adult GH deficiency and organic hypothalamic-pituitary disease were recruited, along with 46 controls. The patients were divided into five groups according to the number of associated hormone deficiencies present. MEASUREMENTS: Hypopituitary subjects underwent assessment of GH secretory status by the ITT, the glucagon test and measurement of serum IGF-I concentration. Controls underwent the glucagon test. After the ITT, glucose and GH levels were measured at baseline, 30, 60 and 90 minutes, and after glucagon at baseline, 90, 120, 150, 180, 210 and 240 minutes. RESULTS: The highest GH value after the ITT in the patient group was 3 microg/l (0.76 +/- 0.82 microg/l), and after the glucagon test the highest GH peak value was 2.9 microg/l (0.64 +/- 0.79 microg/l). A correlation was found between the GH peak and the progressive number of hormone deficiencies. After the glucagon test, the GH peak obtained in the controls at 180 minutes was 9.8 +/- 4.6 microg/l and, on an individual basis, none of the 46 controls failed to achieve peak GH levels higher than 3 microg/l. In the controls, a negative correlation was observed between the GH response to glucagon and age (r = -0.389, P = 0.0075) and body mass index (r = -0.329, P = 0.0254). The accuracy of the glucagon test for differentiating patients from controls, estimated by receiver operating characteristics (ROC) curve methodology, showed that the cut-off of 3 microg/l for the GH peak provides 100% sensitivity and 100% specificity and is a reliable decision threshold. CONCLUSIONS: The glucagon GH test is reliable and provides a clear separation between GH-deficient and normal adults. A single glucagon test with a cut-off of 3 microg/l for the GH peak is diagnostic of GH deficiency in adults and could be considered and studied as an alternative to the ITT.     

The value of detecting surface and cytoplasmic antigens in acute myeloid leukaemia

The immunophenotype of leukaemia cells from 60 patients with acute myeloid leukaemia (AML) was analysed with the APAAP technique using a panel of anti-myeloid and lymphoid associated monoclonal antibodies (McAb). Cells from all cases, including three with negative cytochemical features, were labelled by at least one of the anti-myeloid McAb CD13, anti-myeloperoxidase (anti-Mpo), and/or CD14. The most sensitive marker was CD13, since it was positive in 90% of cases. In two out of three AML cases defined as M0-AML, CD13 was expressed in the cytoplasm but not on the membrane; in these three cases peroxidase (Mpo) was not detected by conventional cytochemistry, but could be demonstrated in all of them using the McAb anti-Mpo. The simultaneous expression of CD14 and CD68 McAb was often confined to the M4 and M5 FAB AML subtypes (92% cases) as compared to the others: M1, M2, M3 (18% cases). Lymphoid antigens were rarely positive (TdT+: 13%, CD7+: 15%, CD19+: 5%) and none of the AML cases were CD3+ or CD10+. By contrast, CD4 was expressed in blasts from 44% of cases and this was not restricted to AML with a monocytic component (M4, M5) but also found in other subtypes. There were no significant differences in the clinical or prognostic features according to the positivity or negativity with TdT and CD4. By contrast, expression of CD7 was associated with refractoriness to the treatment or short complete remission duration, although the number of patients is too small to draw firm conclusions. Our findings support the clinical and diagnostic relevance of immunophenotypic studies in AML.     

Induction of tumor NK-cell immunity by anti-CD69 antibody therapy

The leukocyte activation marker CD69 is a novel regulator of the immune response, modulating the production of cytokines including transforming growth factor-beta (TGF-beta). We have generated an antimurine CD69 monoclonal antibody (mAb), CD69.2.2, which down-regulates CD69 expression in vivo but does not deplete CD69-expressing cells. Therapeutic administration of CD69.2.2 to wild-type mice induces significant natural killer (NK) cell-dependent antitumor responses to major histocompatibility complex (MHC) class I low RMA-S lymphomas and to RM-1 prostatic carcinoma lung metastases. These in vivo antitumor responses are comparable to those seen in CD69(-/-) mice. Enhanced host NK cytotoxic activity correlates with a reduction in NK-cell TGF-beta production and is independent of tumor priming. In vitro studies demonstrate the novel ability of anti-CD69 mAbs to activate resting NK cells in an Fc receptor-independent manner, resulting in a substantial increase in both NK-cell cytolytic activity and interferon gamma (IFNgamma) production. Modulation of the innate immune system with monoclonal antibodies to host CD69 thus provides a novel means to antagonize tumor growth and metastasis.     

Hypocholesterolemia in acute myelogenous leukemia

Plasma-cholesterol concentrations were determined in 85 acute myelogenous leukemia patients. Measurements were repeated in 28 cases during remission. Mean plasma-cholesterol concentration (+/- SD) at diagnosis was 3.95 mmol/l (+/- 1.29). 47 patients (55.3%) had hypocholesterolemia (less than 3.87 mmol/l). Among the main clinical, hematologic and biochemical parameters, only high leukocyte counts were correlated with hypocholesterolemia. As far the FAB subtypes are concerned, the lowest cholesterol levels were observed in leukemias with monocytic component. However, although the same FAB subtypes showed significantly higher leucocytes counts than the other subtypes, both parameters were independently related to low cholesterol levels. Remission was associated with a significant increase in cholesterol levels in those patients with low cholesterol concentrations or high leukocyte counts at diagnosis. These results support the idea that initial hypocholesterolemia in acute myelogenous leukemia is related to the tumoral mass present at diagnosis.     

Impact of response to treatment on survival in multiple myeloma: results in a series of 243 patients

Summary. Two hundred and forty-three patients diagnosed with multiple myeloma (MM) in a single institution over a 22-year period and treated with standard chemotherapy were analysed in an attempt to determine the impact of response to therapy on survival. The overall response rate in 229 evaluable patients was 50.1% (34.9% objective response plus 15.2% partial response). Median survivals of patients with objective and partial response were 43.4 and 42.8 months, respectively, versus 19 months for nonresponders. Median survival of 14 patients who achieved a complete remission was 42 months, whereas in 21 rapid responders (≤ 2 months) median survival was 43.3 months. A significant correlation between response and survival was observed with the landmark (P = 0.0169), the Mantel & Byar (P = 0.0001) and the Cox regression model (P < 0.0001) methods. These results indicate that, in responding patients, neither the degree of response nor the response kinetics has a significant influence on survival. However, the response to therapy is associated with a significantly longer survival in MM patients.     

Absence of Effect of DDAVP Infusion on Platelet Glycoprotein Ib/IX and IIb/IIIa Complexes, and their Interaction with Newly Released von Willebrand Factor

Several possibilities have been raised to explain the beneficial effect of l-deamino-8-D-arginine vasopressin (DDAVP) in several hemostatic disorders but, so far, its exact mechanism(s) of action is still unknown. Aiming to throw new light on the problem, we have investigated: (a) whether DDAVP induces platelet activation or quantitative/qualitative modifications of GPs Ib/IX and IIb/IIIa, and (b) the binding to these glycoprotein receptors of von Willebrand factor (vWF) purified from blood obtained before and after administration of DDAVP. Analysis of the expression of GMP 140 and thrombospondin demonstrated no platelet activation following administration of DDAVP. Binding assays and flow cytometry with antibodies against GPs Ib/IX and IIb/IIIa, the study of the ristocetin-dependent vWF binding, and immunoblotting with an anti-GPIb/IX antibody, demonstrated no quantitative or functional changes of these complexes after the infusion of DDAVP. Finally, native vWF purified from cryoprecipitate, and vWF purified from plasma of one DDAVP-infused volunteer, showed similar binding properties to GPIb/IX and GPIIb/IIIa. These results suggest that DDAVP is quite inert on platelet glycoproteins, and the drug-induced appearance of 'supranormal' high molecular weight vWF multimers seems not to modify the interaction of vWF with its main platelet receptors.     

The 4G/5G polymorphism of the type 1 plasminogen activator inhibitor gene and thrombosis in patients with antiphospholipid syndrome

OBJECTIVE: To investigate the relationship between the 4G/5G polymorphism of the type 1 plasminogen activator inhibitor (PAI-1) gene and thrombotic manifestations in patients with antiphospholipid syndrome (APS). METHODS: We studied a total of 247 patients included in the following 4 groups: 70 patients with primary APS, 104 patients with systemic lupus erythematosus (40 with antiphospholipid antibodies [aPL] and clinical [secondary] APS, 13 with aPL but without clinical APS, and 51 with neither detectable aPL nor a history of thrombosis), 14 asymptomatic individuals with aPL, and 59 patients with thrombosis but without known thrombosis risk factors. A control group of 100 healthy individuals was also analyzed. PAI-1 4G/5G polymorphism was determined by polymerase chain reaction and endonuclease digestion. RESULTS: The allele frequency of 4G/5G in controls was 0.47/0.53. There were no differences in allele distribution among patient groups or between patients and controls. However, a higher frequency of the 4G allele was observed in APS patients with versus those without thrombosis (0.57 versus 0.39; P < 0.05) (odds ratio [OR] 2.83, 95% confidence interval [95% CI] 1.18-6.76). This higher frequency of the 4G allele was attributable to the higher frequency in patients with versus those without arterial thrombosis (0.64 versus 0.43; P < 0.01) (OR 5.96, 95% CI 1.67-21.32), while patients with venous thrombosis had an allele distribution similar to that of those without venous thrombosis (0.49 versus 0.50; P not significant). There was a trend toward higher PAI-1 antigen and activity levels in APS patients and controls with the 4G/4G genotype, but this did not reach statistical significance. CONCLUSION: The presence of the 4G allele of the 4G/5G polymorphism of the PAI-1 gene may be an additional risk factor for the development of arterial thrombosis in APS.     

The Syndrome of Veno-occlusive Disease After Blood or Marrow Transplantation

Veno-occlusive disease of the liver (VOD) was originally described in patients who drank infusions made with plants containing pyrrolizidine alkaloids [1]. This disease was characterized, histologically, by a progressive and concentric non-thrombotic narrowing of the lumina of small intrahepatic veins. Later, VOD was related to other pathogens such as alcohol, contraceptives, toxic oil, liver radiation and several antineoplastic drugs [2–3]. The first case of veno-occlusive disease following bone marrow transplantation (BMT) was reported in 1979 [4]. Since then, BMT has proved to be the main cause of VOD which is one of the leading causes of morbidity and mortality after transplant [5–7]. Clinical manifestations of VOD are very characteristic (jaundice, painful hepatomegaly and fluid retention) but indistinguishable from those produced by other regime-related morphological changes on zone 3 of the liver acinus. For this reason, the term “syndrome of veno-occlusive disease of the liver” has been adopted to designate the clinical manifestations of conditioning regimen toxicity on this zone [8]. This review focuses on the present knowledge of VOD syndrome after BMT.     

Is grey literature essential for a better control of publication bias in psychiatry? An example from three meta-analyses of schizophrenia

Systematic reviews in mental health have become useful tools for health professionals in view of the massive amount and heterogeneous nature of biomedical information available today. In order to determine the risk of bias in the studies evaluated and to avoid bias in generalizing conclusions from the reviews it is therefore important to use a very strict methodology in systematic reviews. One bias which may affect the generalization of results is publication bias, which is determined by the nature and direction of the study results. To control or minimize this type of bias, the authors of systematic reviews undertake comprehensive searches of medical databases and expand on the findings, often undertaking searches of grey literature (material which is not formally published). This paper attempts to show the consequences (and risk) of generalizing the implications of grey literature in the control of publication bias, as was proposed in a recent systematic work. By repeating the analyses for the same outcome from three different systematic reviews that included both published and grey literature our results showed that confusion between grey literature and publication bias may affect the results of a concrete meta-analysis.