Histone H2A.Z is widely but nonrandomly distributed in chromosomes of Drosophila melanogaster.

Variant histones that differ in amino acid sequence from S-phase histones are widespread in eukaryotes, yet the structural changes they cause to nucleosomes and how those changes affect relevant cellular processes have not been determined. H2A.F/Z is a highly conserved family of H2A variants. H2Av, the H2A.F/Z variant of Drosophila melanogaster, was localized in polytene chromosomes by indirect immunofluorescence and in diploid chromosomes by chromatin immunoprecipitation. H2Av was widely distributed in the genome and not limited to sites of active transcription. H2Av was present in thousands of euchromatic bands and the heterochromatic chromocenter of polytene chromosomes, and the H2Av antibody precipitated both transcribed and nontranscribed genes as well as noncoding euchromatic and heterochromatic sequences. The distribution of H2Av was not uniform. The complex banding pattern of H2Av in polytene chromosomes did not parallel the concentration of DNA, as did the pattern of immunofluorescence using H2A antibodies, and the density of H2Av measured by immunoprecipitation varied between different sequences. Of the sequences assayed, H2Av was least abundant on 1. 688 satellite sequences and most abundant on the hsp70 genes. Finally, transcription caused, to an equivalent extent, both H2Av and H2A to be less tightly associated with DNA.

Non-Hodgkin's lymphoma involving the central nervous system.

In 44 out of 758 patients (5.8%) with non-Hodgkin's lymphoma presenting between 1971 and 1982, the central nervous system (CNS) was involved. Patients with a diffuse histology had a 7.6% (34/449) incidence of CNS involvement compared to 3.9% (10/257) for patients with nodular lymphoma. In 63% of patients there was evidence of progressive systemic lymphoma at the time of diagnosis of CNS disease and in 23% CNS relapse occurred in clinical remission. Bone marrow was involved in 34% of patients at diagnosis and in 52% at some time prior to the onset of CNS complications. Cerebrospinal fluid cytology was positive in 63% and an elevated protein level was found in 95% of patients. The median length of survival of the 44 patients was only 3.2 months, but patients who responded to treatment of CNS lymphoma survived significantly longer than those who showed no response or progressed on therapy. Complete response to CNS treatment was achieved in five patients, of whom none relapsed in the CNS and two are long-term disease-free survivors. CNS prophylaxis appears justified for patients with lymphoblastic lymphoma, Burkitt's tumour, and diffuse undifferentiated lymphoma, who are at high risk of developing CNS complications. Patients with diffuse histiocytic, and diffuse poorly differentiated lymphocytic, lymphoma who have bone marrow involvement may also benefit from CNS prophylaxis.

Mantel irradiation for stage I and stage II Hodgkin's disease--results of a 10 year experience.

One hundred and thirty patients with Stage I and II supradiaphragmatic Hodgkin's disease treated with mantle irradiation alone at the Peter MacCallum Hospital, Melbourne between 1968-1977 were analysed retrospectively. The median followup was 7.4 years with a minimum of three years. There were 64 clinically staged (CS) and 66 pathologically staged (PS) patients. The major difference between the two groups was the transdiaphragmatic relapse which occurred in 33% of CS patients, and 7.5% in PS patients. The actuarial five year relapse free survival (RFS) was 48% for CS patients and 67% for PS patients, but the five year overall survival was 90% for both groups, reflecting the impact of salvage treatment. Avid attention must be given to radiotherapy techniques to minimise local treatment failures. High grade nodular sclerosis Hodgkin's disease is associated with poor RFS even after adjustment has been made for stage and constitutional symptoms (p less than 0.003). Further studies will be made on this group of patients who may benefit from combined modality treatment. For PS I and II patients mantle irradiation gives a five year RFS of 67%, thus offering potential for cure in these patients.

Tissue diagnosis in lymphomas.

An accurate histological diagnosis is sometimes difficult to achieve in the lymphoma patient. This problem is accentuated by incorrect choice of noded for biopsy or mishandling of tissues, either at surgery or during the fixative process. Practical guidelines are suggested to help minimize these problems.

Splenectomy for haematological cytopenias in patients with malignant lymphomas.

Haematological cytopenias caused by increased splenic activity occurred in 86 patients with malignant lymphomas (50 patients with stage III or IV Hodgkin disease [H.D.] and 36 with non-Hodgkin lymphomas). Splenectomy was performed in 84 of these 86 patients. There was complete or partial correction of the haematological defect in 90% of the H.D. patients and 89% of the non-Hodgkin patients. Chemotherapy or radiotherapy was started after the haematological defect had been corrected by splenectomy, and as a result 79% of the H.D. patients and 75% of the non-Hodgkin patients had a complete or partial remission of their disease. Increased splenic activity should be considered as a cause of a haematological cytopenia in patients with malignant lymphomas even in those with bone-marrow involvement, since splenectomy is accompanied by excellent results in terms of disease remission with subsequent therapy. 2 patients with H.D. (4%) and 5 with non-Hodgkin lymphomas (14%) died in hospital after splenectomy. Thus the operation was associated with acceptable mortality and morbidity despite the advanced stage of disease in most cases.