Complex morphogenesis of surfaces: theory and experiment on coupling of reaction-diffusion patterning to growth

Reaction-diffusion theory for pattern formation is considered in relation to processes of biological development in which there is continuous growth and shape change as each new pattern forms. This is particularly common in the plant kingdom, for both unicellular and multicellular organisms. In addition to the feedbacks in the chemical dynamics, there is then another loop linking size and shape changes with the reaction-diffusion patterning of growth controllers in the growing region. In studies by computation, the codes must incorporate, alongside the usual solvers of the partial differential dynamic equations, a versatile growth code, to express any kind of shape change. We have found that regulation of shape change in particular ways (e.g. to make narrow-angle branchings) demands new features in our chemical mechanisms. Our growth algorithm is for a surface growing tangentially, but moving outward and changing shape to accommodate the extra area. This is potentially applicable both to the tunica layer of multicellular plant meristems and to the growing tip of the cell surface, e.g. in the morphogenesis of single-celled chlorophyte algae which display branching processes: whorl formation in Acetabularia (Dasycladales) and repeated dichotomous branching in Micrasterias (Desmidiaceae). For computational studies, a hemispherical shell is a reasonable idealization of the initial shape. We describe results of two types of study: (1) Pattern formation by three reaction-diffusion models, with contrasted nonlinearities, on the hemispherical shell, particularly to find conditions for robust formation of annular pattern or pattern for dichotomous branching, both of which are common in plants. (2) Sequential dichotomous branchings in a system growing and changing in shape from the hemispherical start.

[Expression of AC133 vs. CD34 in acute childhood leukemias]

AC133, a newly discovered antigen on human progenitor cells, demonstrating 5-transmembranous domains is expressed by 30-60% out of all CD34+ cells. Our aim therefore was to investigate the extent of human stem-/progenitor cells expressing AC133 antigen in umbilical cord blood, peripheral blood without or following an application of granulocyte-colony stimulating factor (rhG-CSF). The main task was the investigation of bone marrow aspirates derived from children suffering from newly diagnosed acute leukemias, as well as from patients with a relapse or during a complete remission. The determination of antigen expression was done by application of flow cytometry (FACScan analysis) and the usage of newly developed monoclonal antibodies (AC133/1 and AC133/2; Miltenyi Biotec GmbH) in combination with monoclonal antibody directed against CD34-antigens (HPCA-2; BD). Our studies till now show average percentages in umbilical cord blood derived from 43 newborns about 0.294 +/- 0.165% AC133+ vs. 0.327 +/- 0.156% CD34+ hematopoietic stem-/progenitor cells (HSPC). In peripheral blood from 11 healthy donors we verified up to 0.15% CD34+ as well as AC133+ HSPC's. The concentration of progenitor cells was found to be obviously higher in peripheral blood from children with various diseases (neuroblastoma, rhabdomyosarcoma, ALL/AML) and undergoing application with rhG-CSF in order to be prepared for PBSC-transplantation. In those cases we found up to 3.51% AC133+ cells as well as slightly higher values (3.94%) for CD34 antigens. Additionally we quantified 128 bone marrow (BM) samples for AC133+ and CD34+ cells. In 10 BM samples, derived from patients without any neoplasia, the CD34+ cells were about 0.03% and 1.49%, whereas AC133 values were up to 0.64%. Bone marrow aspirates from 53 children with acute leukemias at time of diagnosis (ALL: n = 41/AML: n = 12) have been immunophenotyped and leukemic blast cells have been proved for AC133- and CD34 antigen expression. 32/41 (78%) of lymphoblastic leukemic cells showed to be positive for CD34 antigen and 24/41 (58%) demonstrated AC133 antigens. Interestingly there were 2 ALL-patients with pathological blast cells positive for AC133 but lacking of any CD34 antigens. 42% (5/12) of investigated AML patients showed CD34+ phenotype, on the other hand there were only 25% (3/12) with AC133+ phenotype. Similar values were found in relapsed patients (n = 18). In BM samples from patients during complete remission (n = 47) we could detect percentages up to 5.55% for CD34 and up to 1.25% for AC133 positive stem-/progenitor cells. Such quite high data may be explained by occasionally application of rhG-CSF therapy. Our results till now lead to the conclusion, that it seems to be useful, to recruit quantification of CD34+ HPSC by additionally detecting AC133 antigens. This new stem cell marker (AC133) may be of great value in case of autologous peripheral blood stem cell transplantation (PBSCT) because it could be an alternative to the usual CD34+ MACS selection system.

wt1 gene expression in childhood leukemias

The expression of the Wilms' tumor gene (wt1) was detected in various tissues during embryonic development. Mutations in the wt1 gene probably play an important role in certain tumors, e.g. the Wilms' tumor. Furthermore the expression of wt1 gene was found in some human leukemias. In the present study we investigated the expression of wt1 gene in several types of childhood leukemia by reverse transcriptase-polymerase chain reaction. Bone marrow or peripheral blood of 61 pediatric patients (48 at initial diagnosis, 13 at first or second relapse) were analyzed. wt1 gene expression was detected in 35/48 patients (73%) with newly diagnosed leukemias and in 12/13 cases (92%) who had suffered from relapse. The expression levels were higher for AML than for ALL. The frequency of wt1 expression in different subtypes of acute leukemia was compared with results found in adult patients. Our results show that the frequency of wt1 gene expression in acute childhood leukemias is similar to previous data reported for adults.

Minimal residual disease in leukemia in children

Many chromosomal translocations involved in leukemia have been defined at the molecular level in recent years. In addition to advancing the understanding of pathological mechanisms underlying the transformation process, the cloning and sequencing of the genes altered by the translocations have provided new tools for diagnosis and monitoring of patients. In particular, the polymerase chain reaction (PCR) method yields sensitive and accurate diagnostic and prognostic information. Minimal residual disease (MRD) is not clearly defined. In ALL we define MRD as fewer than 5% blast cells in the bone marrow by conventional cytology and proof of leukemic cells with more sensitive methods. The techniques for detecting MRD are imaging for detection of single leukemic cells in the blood, bone marrow, or other tissues by means of immunocytology or PCR/RT-PCR. Highly sensitive PCR, immunocytology, FACS analysis, or conventional cytology are important tools to use in the process of deciding on appropriate therapy. Detection limits at present are 10(-2) for cytology and FISH, up to 10(-4) for immunological procedures, and 10(-5) to 10(-6) for PCR. But multiple methods also imply the possibility of mistakes (e.g., PCR). The question must be raised what method should be decisive in assessing MRD for evaluating autologous peripheral blood stem cells (PBSC) or autologous bone marrow transplants? Prospective studies will have to answer the question whether MRD should be treated or not and whether purging of bone marrow or PBSC is useful or damaging. When applied, should a positive or a negative immunopurging or a chemotherapeutic purging be used? MRD refers to the organism of the patient as well as to the peripheral blood stem cells and autologous bone marrow that had been taken before myeloablative therapy and kept for retransfusion.

Rapid immunodiagnosis of childhood leukemia using microwave-stimulated APAAP-complex system

Important insights into leukocyte differentiation and the cellular origin of leukemias have been achieved by the use of monoclonal antibodies for the detection of cellular antigens with impact on the diagnosis and classification of hematological malignancies. A successful rapid immunoenzymatic technique using application of microwave irradiation (MIWI) on bone marrow cells of various children with ALL is described. The MIWI-stimulated immunotyping of acute leukemia cells with a panel of monoclonal antibodies against differentiation antigens (i.e. CD2, CD7, CD10, CD19, CD20, CD24, HLA-DR and TdT) has been compared with the conventional APAAP procedure developed by Mason et al 1983. The commercial microwave oven we used operates at 2.45 GHz. Fifteen sec irradiation at 350 W during all incubation steps produced excellent color reactions with Fast Red TR and Fast Blue BB similar to the conventional immunoenzymatic method. The results so far have demonstrated that the application of the MIWI-technique eliminates the need for long incubation periods without loss of sensitivity. With this technique an immunological diagnosis of childhood leukemia cells is possible using air dried smears in an microwave oven within 30 minutes.

[Microwave stimulated cell marker analysis. Possibilities for more rapid immune diagnosis]

We describe a successful rapid APAAP-complex technique using innovative application of microwave irradiation (MIWI) on Ficoll separated peripheral blood mononuclear cell smears of healthy donors. The typing with several monoclonal antibodies (MoAbs) against different cell surface antigens is compared with the conventional APAAP procedure. The commercial domestic microwave oven was operated at 2.45 GHz. Fifteen second irradiation at 350 W during all incubation steps, e.g. primary antibody, bridging antibody and APAAP-complexes produced excellent color reactions with Fast Red TR, Fast Blue BB, New Fuchsin or NBT similar with the conventional immunoenzyme procedure. The routinely usage of a Silicon-Chamber-System developed by us is applicable without limitation under microwave conditions. The results till now have shown that the application of microwave-technique (MIWI) eliminated the need for much longer incubation periods without lost of sensitivity. All immunological markers could be detected in the same degree as observed with the conventional method. We could demonstrate that an immunological diagnosis is possible within 30 minutes using air dried smears in an microwave oven.

[Use of a new silicon chamber system for carrying out immunologic technics with blood and bone marrow samples and histologic specimens]

We are reporting for the first time on the successful application of the newly developed method of Silicon-Chamber-System (SCS). For this purpose we are utilizing a commonly manufactured silicon sealant by which we are able to obtain reaction fields of any size and number. We are applying the sealant on cell- and on tissue-slides without any special preparation. These reaction fields on the slides allow us to immunohistochemically analyse cells with multiple different monoclonal antibodies without running great risk of a cross-reaction between the different immunoreagents. It is a simple inexpensive and convenient method, giving us the opportunity to analyze elaborate cell material.

Expression of markers shared between human haematopoietic cells and neuroblastoma cells

Neuroblastoma (NB) is a solid tumor of childhood with a relatively bad prognosis, with the exception of young infants (less than 1 year), in whom spontaneous regression of tumor burden occurs. The reasons for this are still unknown but immune mechanisms may be involved. In this study, we have examined the ability of several monoclonal antibodies (MoAbs), which recognize markers predominantly expressed on human haematopoietic cells, to react with four human neuroblastoma cell lines (UKF-NB 1-4) and SK-N-SH as control cell line. In order to define the phenotype of NB cells, we used a large panel of MoAbs consisting of 2 major groups: a) well characterized MoAbs raised against antigens of neuroectodermal origin from the Kemshead-serie (e.g. UJ 13A, UJ 127.II, UJ 167.11, UJ 181.4, UJ 223.8, A2B5), b) monoclonal antibodies which have been considered to react with haematopoietic cells (HLA-DR and anti-CD-molecules CD1, CD7, CD9, CD10, CD13, CD16, CD19, CD20, CD24, CD57). The phenotypic analyses were performed at various times of culture by an immunoenzymatic procedure (APAAP-technique). Most of the MoAbs used against neuroblastoma cells showed a strong reactivity pattern with the NB cell lines. None of the antibodies against T-lymphocytes bound to any of the NB cells assayed in our study, with the exception of anti-CD 1. On the contrary, B-cell markers BA-2 (CD9) and BA-1 (CD24) cross-reacted with the NB cells just as well as the marker for NK-cells (CD57), but they did not express reactivity with Leu-11b (CD16), anti-CALLA (CD10) and anti-HLA-DR.

Immunological detection and definition of minimal residual neuroblastoma disease in bone marrow samples obtained during or after therapy

Immunological staining by the alkaline phosphatase/anti-alkaline phosphatase (APAAP) technique has been used to recognize low levels of neuroblastoma cells in bone marrow mononuclear cells. Immunological phenotyping with 11 well characterized monoclonal antibodies was performed on 16 children with neuroblastoma and BM involvement during or after therapy. Neuroblasts were detected in 11 of 16 patients (0.1-5%), whereas BM biopsies on six of these patients were classified as normal. Aspirates, stained conventionally, were positive for pathological cells in three patients only. The comparison of the phenotype of the neuroblastoma cells at the time of diagnosis to the phenotype of the residual cells within one patient revealed differences. The phenotype of residual disease in different patients on the other hand showed a unique pattern. The above mentioned results lead to the conclusion that the immunological procedure is particularly suitable for the analysis of minimal residual neuroblastoma since the technique allows very minor cell populations to be identified in BM samples.

[Immunologic identification of undetectable neuroblastoma cells by current cytohistological studies of bone marrow samples]

Immuno-alkaline phosphatase staining (APAAP technique) has been used to identify neuroblastoma cells on bone marrow samples from 12 children at various stages of the disease. On 72 occasions immunological analyses were performed using a panel of monoclonal antibodies which selectively bind to cells of neuroectodermal origin. In 57 of these procedures, tumor cells were detected, whereas histological and cytological analyses revealed pathological cells in 45 and 37 cases respectively. Reactivity of minimal residual tumor cells--mainly with three MAbs (UJ13A, UJ167.11, A2B5)--points to the fact that these cells belong to a resistant neuroblastoma clone, which remains in bone marrow despite intense therapy. Our study demonstrates that immunological staining may identify and define a small number of neuroblastoma cells which are not yet detectable by traditional histological and cytological criteria.

[Retrospective marker analyses performed with blood and bone marrow smears using an immunoenzyme procedure (alkaline phosphatase-anti-alkaline phosphatase technic)]

In the present study the possibility of immunophenotyping of routinely prepared (air dried) peripheral blood and bone marrow smears is described after storage. The immunoenzymatical alkaline-phosphatase-anti-alkaline-phosphatase (APAAP)-method was carried out in differently stored blood smears (+4 degrees C and -80 degrees C). Last results were compared with originals made from freshly prepared mononuclear cells at time of diagnosis. The results showed no remarkable decrease of antigenicity, neither under the procedure refrigeration and thawing of the frozen smears (-80 degrees C), nor under storage conditions of more than 22 months. In our opinion this highly sensitive method enables us to get additional results from unexplained haematological disorders using retrospective analysis.

[Doppler sonographic flow measurement in the anterior cerebral artery and celiac trunk in infants with coarctation syndrome in comparison with healthy infants]

15 infants (gestational age 47 +/- 11 weeks; weight 3180 +/- 1082 g) with angiocardiographically proven coarctation of the aorta and 53 healthy infants (gestational age 39 +/- 8 weeks; weight 2830 +/- 1418 g) were investigated by echocardiography and pulsed doppler sonography. In all children pulsed doppler recordings were obtained in the anterior cerebral artery (prestenotic reference vessel) and the truncus coeliacus (poststenotic reference vessel). Nine variables were measured from each doppler signal: The maximal systolic velocity, the endsystolic and enddiastolic velocity, the pulsatility-index, the acceleration slope (peak rate of acceleration), the deceleration slope (peak rate of deceleration), the antegrade flow time and the acceleration and deceleration time. The healthy infants showed a pulsatile flow profile in the anterior cerebral artery and the truncus coeliacus. In normal subjects the maximal systolic velocity and the acceleration slope in the truncus coeliacus were always higher than in the anterior cerebral artery. There was no difference in the endsystolic and enddiastolic velocity, the pulsatility-index, the flow times and the deceleration slope. In children with coarctation of the aorta a decreased and nonpulsatile flow in the truncus coeliacus could be shown. The following variables were significantly lower than in the healthy control group: The maximal systolic velocity, the pulsatility-index, the acceleration and deceleration slope and the antegrade flow time and acceleration time. In the anterior cerebral arteries of children with coarctation the maximal systolic and enddiastolic velocity were significantly higher than in the healthy control group. Pulsed doppler recordings were obtained in 9 patients after surgical correction: The maximal systolic and endsystolic velocity, the pulsatility-index, the acceleration and deceleration slope in the truncus coeliacus increased significantly although these values were lower than in the healthy control group. The flow parameters in the anterior cerebral arteries postoperatively showed no significant difference from the preoperative values. Pulsed dopplersonography of the flow in the anterior cerebral artery and the truncus coeliacus is a good method for diagnosis of coarctation of the aorta and postoperative controls.

A double-blind crossover comparison of Orudis (ketoprofen) and indomethacin in the treatment of rheumatoid arthritis

Twenty-three patients with rheumatoid arthritis participated in a double-blind crossover investigation of ketoprofen (Orudis) and indomethacin. Ratings which assessed the degree of joint involvement showed consistently greater improvement with Orudis, and side-effects occurred with less frequency. The majority of patients expressed a definite preference for Orudis.