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The occurrence of apoptosis in choroidal neovascularizations (CNV) has only been described previously in a few cases. However, little is known about the extent and function of apoptosis. We analyzed the incidence of apoptosis in order to find new options in the therapy of CNV. Particular attention was given to the length of time that the process existed before surgery in patients with age-related macular degeneration (AMD).In 34 patients (18 women, 16 men) ranging in age from 20 to 91 years (mean 70.3 years), CNV was detected by angiography. The majority of patients (n = 29) with CNV had AMD, which in most patients affected both eyes. In two patients CNV was due to post-traumatic proliferative vitreoretinopathy, in two other patients CNV occurred after a penetrating bulbus injury, and in one patient pseudoxanthoma elasticum was found. Thirty-four CNV membranes were excised by pars plana vitrectomy via retinotomy, fixed in formalin and embedded in paraffin. Sections were stained with PAS and HE and examined microscopically. The in situ cell-detection kit (TUNEL) was used for immunohistochemical detection of apoptotic cells from fragmented DNA.In 74% (n = 25) of all patients and in 76% (n = 22) of patients with AMD, disseminated or focal apoptotic cells were detectable in the connective tissue, retinal pigment epithelium and in the vascular endothelium. In AMD patients with apoptotic cells, the SNV existed 1-12 months (mean 5.5 months) before surgical intervention. In patients without apoptotic cells, the CNV were present 5-36 months (mean 17 months) before surgery. At the time of surgery, the loss of reading ability had on average been going on 3 months; in patients with apoptotic cells, the mean time from the onset of this symptom was 2.4 months (1 week to 11 months); and in patients without apoptotic cells it was 5 months (1-12 months).Programmed cell death as a regulating pathomechanism was observed in all tissue parts of CNV with variable extension. In patients with AMD, a correlation existed between the length of time that CNV existed before surgery and the incidence of apoptotic cells. Apoptosis was found more frequently in recent CNV than in long-standing lesions. The various activity found in CNV suggests that the success of treatment may depend on the moment of intervention. To characterize the role of apoptosis further inducing and inhibiting factors have to be analyzed.

To detect karyotype changes during the chronic phase of CML, 31 mostly Ph1-positive patients were followed cytogenetically over a period of 3 years. Newly emerging abnormalities, e.g. second Ph1-chromosome, iso17q, trisomy 8, could be correlated with clinical and hematological characteristics of the course of the disease if they constituted the first additional chromosomal change. In 54 patients with suspected or established blast crisis, TdT determinations were performed. Out of 27 patients with verified blast crisis, 6 showed markedly elevated enzyme activities in the leukemic blast cells. These patients proved to be very sensitive to cytostatic therapy with prednisone and vincristine. The continuous observation of TdT levels enabled us to initiate a controlled and, with respect to the quality of life, a less toxic therapy. Our data indicate that serial chromosomal analyses and TdT determinations are of great value in predicting prognosis and therapeutic responsiveness in CML.

Terminal deoxynucleotidyl transferase (TdT) is a unique DNA-polymerase which is restricted to a few organs (thymus, bone marrow and blood). Therefore, the enzyme is suited for the role of a tumor marker in all other organs. The immunohistological demonstration, hitherto, was mainly hampered by the lack of potent and specific antibodies and by the readiness of the enzyme to diffuse. Now, these problems are solved. The immunohistological demonstration of TdT can be used to classify acute leukemias and lymphoblastic non-Hodgkin-lymphomas of children and to early recognize relapse situations.

Deoxynucleotidyl transferase (TdT) is of diagnostic and therapeutic importance in acute leukaemia and malignant lymphoma. Previous methods for determining TdT activity by biochemical assay are complex and require the use of radioactive substances. There now is available a specific antibody for immunofluorescent demonstration of TdT. The two methods were compared on samples from 43 patients with leukemia or malignant lymphoma. There was very good agreement. High TdT activity was found in 12 of 14 patients with acute lymphatic leukemia and in one of two with acute undifferentiated leukaemia. TdT activity was absent with acute and chronic myeloid leukaemia, chronic lymphatic leukaemia and non-Hodgkin's lymphoma of low malignancy. Immunofluorescence assay, although its results are of similar significance to that obtained with the biochemical tests, is simpler to do. Furthermore, it can be done on normal bone-marrow smear or lymph-node preparations and can be correlated with the morphological findings.

Terminal deoxynucleotidyl transferase (TdT) was examined in mononuclear peripheral blood cells (pB) and bone marrow (BM) specimens of 63 children with acute leukemia (AL). The enzyme activity in normal specimens (pB, BM) was below 0.2 U/10(8) cells; whereas, 49 of the 52 children with acute lymphoblastic leukemia (ALL) at diagnosis showed an activity in the range 1.2--60 U/10(8) cells. 2 of the remaining 3, devoid of TdT activity, were found to be B-cell leukemia. Patients with acute non-lymphoblastic leukemia (ANLL) were generally TdT-negative. Elevated level of TdT activity was detected in only one of 11 children with ANLL. In one patient with acute leukemia two distinct populations of cells with lymphoblastic (87%) and myeloblastic characteristics were evident. The clinical course and cell marker studies were consistent with the interpretation of a defect at the level of the common stem cell giving rise to a TdT-positive lymphoblastic cell population at diagnosis and, following the initial ALL-therapy (4 weeks), a predominant TdT-negative myeloblastic population. TdT as a marker for the modulation of chemotherapy was examined in the remission phase of the disease. Of the nine patients in the first 3 months of remission, one was found to have elevated level of TdT activity (2.5 U/10(8) cells). These data define the usefulness of TdT in the classification of acute leukemia.