Early development of the lower deciduous dentition and oral vestibule in human embryos

The aim of this work was to investigate the early development of the deciduous dentition and oral vestibule in the human embryonic lower jaw. Histological sections and three-dimensional reconstructions from prenatal weeks 6-9 were used. A continuous anlage for the oral vestibule did not exist in the mandible. In contrast to the upper jaw, where we previously observed that the dental and vestibular epithelia developed separately, two dento-vestibular bulges differentiated in the incisor region of the mandible. The lingual parts of each bulge were found to give rise to the respective central and lateral incisors, whereas the labial parts differentiated into the vestibular epithelium. In the canine and molar areas, the dental and vestibular epithelia originated separately. Later, the segments of the vestibular epithelium fused into the labial vestibular ridge, giving rise to the lower oral vestibule in the lip region. In the cheek region, the oral vestibule was found to originate in the mucosal inflection between the developing jaw and the cheek. A similar heterogeneous developmental base for the oral vestibule was also observed in the upper jaw. There is thus no general scheme for the early development of the dental and vestibular epithelia that applies to both the upper and lower jaws, and to both their anterior and posterior regions.     

Preservation of Human Erythrocytes in the Liquid State: Biological Results with a New Medium

Abstract. Red blood cells (RBC) were collected with citrate-phosphate-dextrose (CPD) in a blood-pack optimal additive system. After concentration to 90% hematocrit they were diluted with saline-adenine-glucose medium (SAG-RBC), and stored for 35 days. In this work the RBC were stored in the presence of leukocytes. The SAG medium allows RBC conservation during 35 days at +4°C. The adenosine triphosphate (ATP) level of RBC is compatible with their survival. During the first 2 weeks, hemolysis of SAG-RBC was not greater than in CPD blood. Nevertheless, hemolysis reached 1.49% on day 35, and there was a marked increase in RBC osmotic fragility. Scanning electron-microscopic studies of 35-day RBC showed that the majority of them became echinocytes. After incubation in fresh frozen plasma, the RBC recovered satisfactory osmotic resistance and normal disc shape. The post-transfusion viability was normal with >70% recovery after 48 h. The in vivo restoration of 2,3-diphosphoglycerate (2,3-DPG) was rapid in the transfused SAG-RBC, 50% of the initial 2,3-DPG level being restored in 1 h. The in vivo studies proved that the functional quality of these RBC was compatible with their use in transfusion. The most important problem concerns the supernatant hemoglobin level of the SAG-RBC to be used for massive transfusion.     

Comparative Preclinical Study of Three Bone Marrow Purging Methods Using PCR Evaluation of Residual t(14;18) Lymphoma Cells

The t(14;18) chromosomal translocation occuring in most follicular lymphomas can be exploited by a Bcl2/JH polymerase chain reaction (PCR) to detect residual disease and to monitor the effectiveness of ex-vivo tumor cell immunological purging. We first demonstrated the 10^-5 Bcl2/JH PCR sensitivity with serial dilutions of OCY-LY8 lymphoma cell lines in normal mononuclear cells; and then the specificity and reproductibility of this technique by analysing follicular and non follicular lymphoma samples. With the Bcl2/JH PCR, we tested the efficiency of three marrow purging protocols with an experimentally contaminated bone marrow either treated by three anti-B cell monoclonal antibodies (mAb) followed by three rounds of rabbit complement or two rounds of immunomagnetics beads. Samples obtained after each purging were amplified by Bcl2/JH PCR and hybridized with PFL3 probe. We were able to produce a 2 to 3 log tumor cell reduction after three rounds of complement and a 4 to 5 log reduction after two rounds of beads.

This study showed that it is feasible to use the Bcl2/JH PCR technique for residual cell lymphoma detection in patients undergoing intensive chemotherapy or BM transplantation. These results indicate that ex-vivo immunomagnetic BM purging is probably superior to complement mediated lysis for the eradication of B lymphoma cells from the marrow of patients undergoing autologous transplantation.     

Depletion of T-lymphocytes in donor marrow with pan-T monoclonal antibodies and complement for prevention of acute graft-versus-host disease: a pilot study on 29 patients

A cooperative study was done on ex vivo treatment of bone marrow for the prevention of acute graft-versus-host disease (GvHD), in which either CD2-CD5-CD7 (14 patients) or CD2-CD3 (15 patients) monoclonal antibody cocktail and complement were used. In this study, 29 patients (12 female, 17 male; average age, 22-1/2 yr) received T-cell-depleted allograft through complement cytolysis, 26 from HLA-identical donors and 3 from HLA-mismatched donors. All of the patients had malignant disease with poor prognosis; 21 had acute leukemia, 7 had chronic granulocytic leukemia, and 1 had multiple myeloma. After bone marrow transplantation (BMT), GvHD prophylaxis was maintained in 12 patients (group 1), was stopped at day 11 in 6 patients (group 2), and was not administered to 11 patients (group 3). The treatment removed 92.65 +/- 5.36% of donor bone marrow T-cells with one round of complement lysis. Of 3 patients who received mismatched transplant, 2 did not achieve engraftment. Engraftment was achieved in all of the patients who had matched BMT. Two patients had acute GvHD, 1 with grade 2 in group 1, and 1 with grade 3 in group 3. No patient has developed chronic GvHD; for 9 patients, the follow-up is longer than 6 months. Five patients relapsed within 6 months after BMT. Eighteen patients are alive and well in complete remission, with an average follow-up of 7.5, 10.6, and 2.7 months for patients in groups 1, 2, and 3, respectively.     

Right atrial tear associated with a tumour in the right atrium after blunt chest trauma

Occult cardiac injury following blunt trauma is more commonthan generally suspected. Myocardial contusion is not rare,however, it is generally a benign disorder which often remainsundiagnosed. We report a case of a right atrial rupture afterblunt chest trauma causing a tamponade. A 24-year-old man was involved in a violent car accident andhe presented in a state of collapse. A multislice computed tomographyindicated a pericardial effusion (Figure 1). A transthoracicechocardiography was performed and confirmed pericardial effusionwhich was hyperechoic (Figure 2, Movie 1). Concerns abouta possible mass in the right atrium led to examination withtransesophageal echocardiography (Figure 3, Movie 2) whichrevealed the presence of a voluminous mass in the right atrium.The patient successfully underwent cardiac surgery to removethe mass, identified as a blood clot, and to repair the atrialtear. The present case is of special interest because of therarity of documented incidents of blunt chest trauma causingright atrial tear and illustrates the usefulness of transesophagealechocardiography in completing the diagnosis in the event ofhaemopericardium.     

Oxidation of methionine 63 and 83 regulates the effect of S100A9 on the migration of neutrophils in vitro

The calcium-binding proteins S100A8 and S100A9 and their heterocomplex calprotectin are abundant cytosolic constituents in human neutrophils, constitutively expressed by mucosal epithelium and in association with inflammation by epidermal keratinocytes. S100A8 and S100A9 are pleiotropic proteins, which partake in the regulation of leukocyte migration. This study was designed to investigate the effect of S100A9 on neutrophil migration and to explore the mechanisms that regulate this effect. Based on previous results with S100A8, we hypothesized that S100A9 repels neutrophils and that oxidation of S100A9 regulates this function. Using standard Transwell chemotaxis assays and site-directed mutagenesis, we show that S100A9 exerts a chemo-repulsive (fugetactic) effect on peripheral neutrophils, an effect abolished by oxidation of S100A9. After substitution of methionine 63 and 83 for alanine, S100A9 maintained its fugetaxis activity, even in inhibitory, oxidative conditions. Together, the data suggest that S100A9 serves as a molecular switch for oxidative control of inflammation regulated by the oxidation of species-conserved methionine residues. In healthy mucosal tissue, expression of S100A9 by the epithelium may serve to inhibit leukocyte recruitment. However, conditions of oxidative stress, including infection and overgrowth of opportunistic pathogens, may abrogate this activity by neutralizing S100A9 as a result of its oxidative alteration.     

Rac-dependent monocyte chemoattractant protein-1 production is induced by nutrient deprivation

Under ischemic conditions, the vessel wall recruits inflammatory cells. Human aortic endothelial cells (HAECs) exposed to hypoxia followed by reoxygenation produce monocyte chemoattractant protein-1 (MCP-1); however, most experiments have been performed in the presence of nutrient deprivation (ND). We hypothesized that ND rather than hypoxia mediates endothelial MCP-1 production during ischemia, and that the small GTP-binding protein Rac1 and reactive oxygen species (ROS) are involved in this process. ND was generated by shifting HAECs from 10% to 1% FBS. Superoxide production by HAECs was increased 6 to 24 hours after ND, peaking at 18 hours. MCP-1 production was increased over a similar time frame, but peaked later at 24 hours. These effects were blocked by treatment with antioxidants such as superoxide dismutase mimetic and N-acetylcysteine (NAC), or NADPH oxidase inhibitors, DPI and gp91ds-tat. Superoxide and MCP-1 production were enhanced by RacV12 (constitutively active) in the absence of ND, and were inhibited by RacN17 (dominant-negative) adenoviral transduction under ND, suggesting that the small G-protein Rac1 is required. In conclusion, ND, an important component of ischemia, is sufficient to induce MCP-1 production by HAECs, and such production requires a functional Rac1, redox-dependent pathway.     

Cost-effectiveness of CD34+ dose in peripheral blood progenitor cell transplantation for non-Hodgkin's lymphoma patients: a single centre study

Intensive high-dose chemotherapy with peripheral blood progenitor cell (PBPC) transplantation is a common strategy for aggressive non-Hodgkin's lymphomas (NHL). A retrospective cost-effectiveness analysis of CD34+ cell dose was carried out. Between 1994 and 1998, 28 patients were included. Efficacy was measured by the length of aplasia. Data collection concerned the period from graft day until discharge from hospital, and the post-graft period until graft day +100. Patients transplanted using a cell dose greater than 5 x 106/kg were found to have a faster hematological recovery. Average length of post-graft hospitalization was shorter and fewer blood products were required for patients with more than 5 x 106/kg CD34+ cells transplanted. Hospitalization was the major cost driver. A large reduction in procedure cost was obtained with a CD34+ cell count higher than 5 x 106/kg (-US$2740, -11%). This difference was directly related to hospitalization (-US$860) and platelet units transfused (-US$1,340). A sensitivity analysis showed the robustness of results. Our findings indicated that a CD34+ cell dose higher than 5 x 106/kg was more cost-effective than a lower dose in NHL patients. The collection of 5 x 106/kg CD34+ cells appeared necessary to optimize the PBPC procedure.     

Mild isocapnic hypoxia enhances the bronchial response to methacholine in asthmatic subjects

We studied the effect of mild isocapnic hypoxia (FIO2 = 15.5%) on lung mechanics, heart rate, circulating plasma catecholamines, and bronchial responsiveness to methacholine in ten asthmatic adults. Hypoxia did not alter lung mechanics (i.e., dynamic pulmonary compliance [CLdyn], pulmonary resistance [RL]) nor did it increase plasma catecholamines, but it significantly increased bronchial responsiveness to aerosolized methacholine, as assessed by the fall in forced expiratory volume in one second (FEV1: 1.2 +/- 0.18 versus 0.9 +/- 0.14 L/s, p less than 0.05), the rise in RL (RL: 19.1 +/- 1.4 versus 8.4 +/- 1 cm H2O/L/s, p less than 0.05), and the steeper slope of the dose-response curve to methacholine. We concluded that the hypoxic characteristic of asthmatic attacks may aggravate airflow obstruction.