Preservation of islet function and morphology after transplantation into high dose streptozotocin-diabetic rats

Rats made diabetic with 0.15 g/kg streptozotocin showed a complete absence of islet B cells in their pancreases, even after 3-6 months of normoglycaemia. Glucagon- and somatostatin-containing cells were preserved. In these animals transplantation of 5,000 cultured fetal islets was required to restore normal blood glucose and intermediary metabolite profiles after a meal challenge, while 2,000 islets resulted in a marked metabolic disturbance. The larger number of islets produced comparable effects whether transplanted under the kidney capsule or into the splenic pulp. In either site, however, considerable proliferation of adipose tissue was found by 3-6 months. Transplanted islets were then demonstrated to retain the normal morphology with a central mass of insulin-containing cells surrounded by a ring of A cells in which a few D cells were embedded.

RCH-ACV: a lymphoblastic leukemia cell line with chromosome translocation 1;19 and trisomy 8

A cell line (RCH-ACV) was established from a bone marrow sample of a child with acute lymphoblastic leukemia (ALL). The cell line lacked Epstein-Barr virus nuclear antigen and exhibited a recently described nonrandom chromosome translocation, 1;19, thought to be associated with pre-B-ALL and poor prognosis. Banding studies confirm that the breakpoint of chromosome #19 occurs at p13.3. Cell surface marker analysis using a panel of monoclonal antibodies revealed markers consistent with common ALL phenotype. Although the cells did not show cytoplasmic immunoglobulin, studies of the immunoglobulin gene rearrangement confirmed the pre-B phenotype. This cell line could be of great value to studies of the role of the specific translocation 1;19 in the etiology of pre-B-ALL.

The human leucocyte P30 antigen: properties and assessment of value as a clonal marker

FMC3 and FMC29 are monoclonal antibodies which react with a 30,000 Dalton molecule expressed on the lymphocyte surface membrane. The molecule is a protein which does not appear to be N-glycosylated. The antigen, which is also expressed intracellularly, does not appear to be a marker of differentiation or maturation. Polyclonal cell populations, such as peripheral blood lymphocytes, show a bimodal distribution of surface antigen density, whilst monoclonal cell populations analysed quantitatively showed unimodal antigen density distributions. This suggests the antigen may be a clonal marker.

Is aplastic anaemia due to abnormality of D.N.A.?

Lymphocytes from eleven patients with aplastic anaemia were cultured with various agents which interact with D.N.A., and the proliferative responses to phytohaemagglutinin were measured. Lymphocytes from seven of the eleven patients were unduly sensitive to bleomycin, an agent causing strand breaks in D.N.A. The findings suggest that D.N.A. in these seven patients was abnormal, possibly as a result of an abnormality of D.N.A. repair. It is suggested that in aplastic anaemia D.N.A. damage in stem cells may lead to a failure of proliferation.

A controlled trial of androgen therapy in experimental chronic hypoplastic marrow failure

A controlled trial of an androgen, 17-nortestosterone decanoate, was carried out to test its effect as therapy in an experimental model of chronic hypoplastic marrow failure. No effect was detected.

Residual marrow damage: possible explanation for idiosyncrasy to chloramphenicol

The effect of oral administration of chloramphenicol was studied in normal mice and mice having residual marrow damage. In the concentration used the drug had no detectable effect on the marrow of normal mice but caused a progressive fall in the numbers of pluripotential stem cells and granulocytic progenitor cells in mice bearing residual marrow damage. However, cells taken from such mice were no more sensitive than normal cells to the in vitro action of chloramphenicol. The results suggest that unrecognized residual marrow damage can be an aetiological factor in marrow failure due to drug idiosyncrasy.

Observer error in histological assessment of marrow hypocellularity

Observer error in the assessment of marrow hypocellularity was studied by examining histological sections from 37 mice having normal or reduced marrow cellularity and comparing the estimated cellularity with a previously measured value. For marrows or mild or moderately reduced cellularity the subjective estimate of cellularity was almost valueless both in terms of accuracy and reproducibility. Only severely hypocellular marrows, having a cellularity of less than 17% of normal, could be recognized as being abnormal with some degree of accuracy and reproducibility.