Hematopoietic progenitors and interleukin-3-dependent cell lines synthesize histamine in response to calcium ionophore

The calcium ionophore A23187 promotes histamine synthesis in murine bone marrow cells by increasing the expression of mRNA encoding histidine decarboxylase (HDC), the histamine-forming enzyme. The cells responsible for this biological activity copurify with hematopoietic progenitors in terms of density, light scatter characteristics, and rhodamine retention, similar to interleukin (IL) 3-induced histamine- producing cells. Yet, the effect of calcium ionophore is not mediated by IL-3. The most purified rhodamine-bright bone marrow subset contains 80% cells that respond to calcium ionophore by increased HDC mRNA expression. This high frequency makes the involvement of one particular progenitor subset in histamine synthesis unlikely. The finding that all IL-3-dependent cell lines tested so far exhibit increased histamine production and HDC mRNA expression in response to calcium influx lends further support to this notion. Cell lines requiring other growth factors or proliferating spontaneously lack this ability. Finally, it should be noted that IL-3-dependent cell lines do not produce histamine in response to their growth factor. It might, therefore, be suggested that the pathway transducing the signal for increased histamine synthesis after IL-3 receptor binding in normal hematopoietic progenitors is modified in these cell lines.     

Vascular and cellular changes accompany altered expression of angiopoietins in placenta of non-complicated ART pregnancies

Background: ART is steadily performed for infertility cases and most of the previous researches have focused on complicated pregnancies. Nonetheless, few ones have concerned with placenta of ART in non-complicated pregnancies.Objectives: To investigate the expression of angiopoietins (ANG) and their receptor, TIE-2, in placenta of full-term non-complicated pregnancies having ART (n = 28) versus those with spontaneous conception (n = 28) together with the histological as well as morphometric analysis.Results: While no prominent changes were noticed in the histological structure of the placenta ART pregnancies, it showed a significant decrease (p < 0.05) in the percentage of syncytial area and numbers of syncytial knots with insignificant reduction in the placental villous area. Vascular changes in the form of significant decrease (p < 0.05) in the chorionic vessel diameter and significant increase (p < 0.05) in percentage of vessel area were detected in the ART placenta. In addition, the levels ANG-1, ANG-2 and TIE-2 were significantly increased (p < 0.05) in the ART placentas compared with those of SC.Conclusions: We demonstrated that there is an altered expression of angiopoietins accompanying the morphometric changes occurring in placenta of ART pregnancies. These changes may indicate vascular and cellular adaptation mechanism for a potential subclinical hypoxia in placenta of ART even in non-complicated pregnancies.     

Dentomaxillofacial manifestations of Gaucher's disease: preliminary clinical and radiographic findings

Objectives

A wide variety of manifestations is presented in patients with Gaucher''s disease (GD), including bone, haematology and visceral disturbances. This study was conducted to ascertain the main maxillofacial abnormalities by means of clinical survey, panoramic and cone beam CT (CBCT); to compare the patient''s group with an age–sex matched control group; and to correlate clinical and radiological data.

Methods

Ten patients previously diagnosed with GD were submitted to clinical and radiological surveys (CBCT and panoramic radiographs). The examination consisted of anamnesis, extra- and intraoral examinations and analyses of each patient''s records. Imaging data were collected from the point of view of 3 observers, and the results compared with a healthy group (20 individuals) by means of statistical analysis (Fisher''s exact test).

Results

Gaucher patients had significantly more manifestations than otherwise healthy carriers. The most prevalent findings were enlarged marrow spaces, generalized osteopenia and effacement of jaw structures (mandibular canal, lamina dura and mental foramen). Here we describe a case in which thickening of the maxillary sinus mucosa was observed on CBCT rather than opacification of the sinus as seen on panoramic radiographs. Pathological fractures, root resorption and delay on tooth eruption were not observed.

Conclusions

A poor relationship could be observed between clinical and radiological data. Patients showed important bone manifestations, which require careful diagnostic and surgical planning whenever necessary. Although panoramic radiographs have shown significant differences, CBCT is more effective in pointing out differences between patients and a control group, thus showing it as an important tool for evaluation of Gaucher patients.     

Use of multiple T cell-directed intact ricin immunotoxins for autologous bone marrow transplantation

The monoclonal antibodies (MoAb) T101, G3.7, 35.1, and TA-1 were conjugated to intact ricin using a thioether linkage. These MoAb detect, respectively, the CD5[gp67], CD7[p41], CD2[p50], and [gp95, 170] determinants that are found in the vast majority of cases of T cell acute lymphocytic leukemia (T-ALL). The resulting immunotoxins (ITs) and an equimolar mixture of these ITs were evaluated as potential purgative reagents for autologous transplantation in T-ALL. Leukemic cell lines were used to compare the kinetics of protein synthesis inactivation mediated by each IT. The cells were treated with IT in the presence of lactose in order to block the native binding of ricin. The observed rates of protein synthesis inactivation correlated with target antigen expression detected by fluorescence-activated cell sorter analysis. Of the four ITs, T101-ricin (T101-R) exhibited the fastest rate of inactivation, followed in order by G3.7-ricin, TA-1-ricin, and 35.1-ricin. At concentrations greater than 300 ng/mL, a cocktail containing an equimolar amount of all four ITs (referred to as the four- IT cocktail) exhibited kinetics that were as fast or faster than those of T101-R. The long-term cytotoxic effects of individual ITs and the four-IT cocktail were evaluated using a sensitive clonogenic assay. Each IT was specifically cytotoxic and inhibited 1 to 4 logs of clonogenic leukemic cells at doses (300 to 600 ng/mL) that can be used clinically. The four-IT cocktail was highly cytotoxic; a concentration of 300 ng/mL inhibited greater than 4 logs of leukemic cells while sparing the majority of committed (CFU-GM, CFU-E) and pluripotent (CFU- GEMM) hematopoietic stem cells. The determination of both short-term kinetics of protein synthesis inactivation and longer-term inhibition of clonogenic growth allowed new insight into cell killing by IT. Our results suggest that ITs continue to act on clonogenic target cells for a period of three to five days. Interestingly, the four-IT cocktail was not as potent against clonogenic leukemic cells as T101-R alone, although it exhibited kinetics of protein synthesis inhibition that were as fast as those of T101-R alone. This finding suggests that internalized ITs may differ in the length of time they remain active within the cell. Our results also demonstrate the importance of using several different assays to evaluate IT reagents.     

Leukemic cell growth in SCID mice as a predictor of relapse in high- risk B-lineage acute lymphoblastic leukemia

Mice with severe combined immunodeficiency (SCID) provide a model system to examine the in vivo homing, engraftment, and growth patterns of normal and malignant human hematopoietic cells. The relation between leukemic cell growth in this model and the treatment outcome in patients from whom cells were derived has not been established. Leukemic cells from 42 children with newly diagnosed high-risk B- lineage acute lymphoblastic leukemia were inoculated intravenously into CB.17 SCID mice. Mice were killed at 12 weeks or when they became moribund as a result of disseminated leukemia. All mice were necropsied and subjected to a series of laboratory studies to assess their burden of human leukemic cells. Twenty-three patients whose leukemic cells caused histopathologically detectable leukemia in SCID mice had a significantly higher relapse rate than the 19 patients whose leukemic cells did not (estimated 5-year event-free survival: 29.5% v 94.7%; 95% confidence intervals, 11.2% to 50.7% v 68.1% to 99.2%; P < .0001 by log- rank test). The occurrence of overt leukemia in SCID mice was was a highly significant predictor of patient relapse. The estimated instantaneous risk of relapse for patients whose leukemic cells caused overt leukemia in SCID mice was 21.5-fold greater than that for the remaining patients. Thus, growth of human leukemic cells in SCID mice is a strong and independent predictor of relapse in patients with newly diagnosed high-risk B-lineage acute lymphoblastic leukemia.     

Monoclonal antibody T101 in T cell malignancies: a clinical, pharmacokinetic, and immunologic correlation

Eight patients with cutaneous T cell lymphomas (CTCL) and five with various other T cell malignancies were treated with mouse monoclonal antibody (MoAb) T101. Doses of 1 to 500 mg were administered weekly over a two-hour period and resulted in one complete remission (convoluted T cell lymphoma) and one partial remission (CTCL). Remission duration was 6 weeks and 3 months, respectively. Frequent toxicities were pruritus, hives, flushing, and shortness of breath. Supraventricular arrhythmias and blood pressure instability were also observed. Complete targeting of peripheral blood T cells was achieved with 1 mg of MoAb in the nonleukemic patients (WBC less than 10,000/microL), and free, bioavailable antibody was present at the next (10-mg) dose level. Even higher doses resulted in substantial antibody excess that persisted for as long as 6 weeks. Serum concentrations of MoAb decreased with increasing number of peripheral blood T cells, and 25 to 35 mg of T101 were required for induction of antibody excess in leukemic patients. Excess antibody induced antigenic modulation, which was of consequence only if MoAb excess persisted to the next treatment. In the original treatment, the rapidly administered MoAb was able to target and remove peripheral blood T cells before the development of antigenic modulation. Antimouse antibodies developed in three patients. Their presence rendered further therapy ineffective and was associated with an anaphylactic reaction in one patient. Development of these antibodies could not be predicted by lymphoproliferative assays. In these assays, however, the T101 protein strongly stimulated the mononuclear cells of the patient who reached the only complete remission of this trial. Immunologic stimulation by the MoAb thus might have played a role in this patient's antitumor response. In summary, therapy with MoAb T101 was specific but only modestly efficacious. Rapid infusion of nonmodulating doses of antibody provided excellent targeting and removal of peripheral blood T cells and might be a valid approach in future trials with immunoconjugated T101.     

Reduction of serum matrix metalloproteinase 1 and matrix metalloproteinase 3 in rheumatoid arthritis patients following anti- tumour necrosis factor-alpha (cA2) therapy

Matrix metalloproteinase (MMP)-1 and MMP-3 levels were measured in serum samples from rheumatoid arthritis (RA) patients undergoing a double-blinded placebo-controlled trial with the chimaeric anti-tumour necrosis factor (TNF)-alpha antibody cA2. Both MMP-1 (P < 0.015), but to a larger extent MMP-3 (P < 0.001) levels were elevated in all RA patients prior to the commencement of the trial compared with normal control sera. Following cA2 therapy, MMP-1 and MMP-3 levels were assessed in the placebo, and 1 and 10 mg/kg cA2-treated groups at 7, 14, 21 and 28 days. In both the 1 and the 10 mg/kg cA2-treated groups, a significant decrease in serum MMP-3 levels at all time points was observed, reducing maximally to 41% of pre-infusion values at day 7. MMP-1 levels were also reduced, but less dramatically than MMP-3, to 85% of pre-infusion values after 14 days in the 10 mg/kg cA2 treated group. In a separate non-placebo-controlled study, we also evaluated the tissue inhibitor of metalloproteinase (TIMP)-1 levels in plasma following cA2 infusion. Pre-infusion TIMP-1 levels were above the normal control range, but were significantly reduced (P < 0.035) 14 days after infusion to 72% of pre-infusion values. This study confirms previous reports that MMP-3 levels are elevated and correlate with measures of inflammation in RA, and furthermore demonstrate that serum MMP-3 and MMP-1 levels are downmodulated following anti-TNF-alpha antibody therapy. Whilst serum MMP-3 levels correlated with C-reactive protein (CRP) both prior to and following anti-TNF-alpha antibody therapy, it remains to be demonstrated that serum MMP-3 and/or MMP-1 levels reflect the cartilage and bone resorptive processes which are evident in this disease.