Biomedical subjects

D S Powell

Publications and source records attributed to D S Powell.

9 recordsLinked to original sources

PubMed2003

Apolipoprotein E genotype, islet amyloid deposition and severity of Type 2 diabetes.

Islet amyloid is found in 90% of patients with Type 2 (non-insulin-dependent) diabetes at post-mortem. More extensive amyloidosis is associated with decreased islet function and requirement for insulin therapy. Severity of cerebral amyloidosis in Alzheimer's disease (AD) is increased in subjects with the apolipoprotein E (ApoE) epsilon 4 allele. To determine if ApoE genotype was associated with severity of islet amyloidosis and diabetes, samples were genotyped from 32 specimens of post-mortem pancreas and from patients classified by disease progression. DNA was extracted from blood samples from Caucasian patients diagnosed with Type 2 diabetes, at age >40 years, classified according to disease progression: group 1 on oral therapy for at least 10 years from diagnosis, (n=147) and group 2, requiring insulin within 6 years from diagnosis, (n=187). ApoE genotype was determined by restriction-fragment length polymorphism analysis. DNA in pancreatic extracts (23 diabetic; 9 non-diabetic subjects) showed no association of ApoE polymorphisms with either degree of islet amyloidosis or disease severity. The distributions of ApoE epsilon 2, epsilon 3 and epsilon 4 were similar in both clinical patient groups and in the non-diabetic group and unrelated to progression of disease. It is unlikely that the common polymorphisms for the ApoE gene are linked to amyloid formation or progression of islet dysfunction in Type 2 diabetes.

Adult↗

PubMed1997

Secondary cytokines interact in sequence with interleukin-1alpha (IL-1alpha) with or without macrophage colony-stimulating factor (M-CSF) to further accelerate granulopoietic recovery in myelosuppressed animals.

Interleukin-1alpha (IL-1), by itself, accelerates both granulopoietic and thrombopoietic recovery in the 5-fluorouracil (5-FU) myelosuppressed mouse (FUM). As a primary cytokine, IL-1 also interacts in concert with macrophage colony-stimulating factor (M-CSF) to synergistically enhance hematopoietic recovery in the FUM. As part of our continuing interest in cytokine sequencing, studies were carried out to determine whether the addition of several secondary cytokines (GM-CSF, IL-3, and IL-6) to IL-1 (+/-M-CSF) would further enhance the stimulatory effects of the primary cytokine(s) on hematopoietic recovery in FUM. Throughout these studies, IL-1 (+/-M-CSF) was administered for 2 days to the FUM, and the secondary cytokines were given either in concert (days 1 and 2) or in sequence (days 3-6) or both with the primary cytokine(s). Based on the magnitude of 7-day post-5-FU granulocyte recovery, the results demonstrated that the synergistic effects of IL-1 + M-CSF treatment on granulopoietic recovery in FUM could not be duplicated by substituting either IL-3, IL-6, or GM-CSF for M-CSF. Nonetheless, the secondary cytokines were observed to enhance the stimulatory effects of IL-1 under the following administration schedules: (1) 2 days of IL-1, followed by a sequential treatment (days 3-6) with either IL-3 or IL-6, (2) 2 days of IL-1 + GM-CSF followed by an additional 4 days of GM-CSF alone, and (3) 2 days of IL-1 + GM-CSF followed by 3-4 days of a combination of GM-CSF and either IL-3 or IL-6. Although these cytokine treatment schedules led to an enhanced granulocyte recovery (vs. IL-1 alone) in FUM, the day 7 granulocyte numbers never exceeded those observed after 2 days of IL-1 + M-CSF. Similarly, granulocyte recovery in FUM receiving 2 days of IL-1 + M-CSF followed by either GM-CSF or IL-3 also was significantly greater than that observed with IL-1 + M-CSF alone. In contrast, however, the sequential administration of IL-6 with IL-1 + M-CSF, unlike IL-1, failed to further enhance granulopoietic recovery, suggesting that there may be an antagonism between IL-6 and M-CSF in the FUM. In summary, therefore, the secondary cytokines were found to interact more effectively when they were administered in sequence, rather than in concert, with both IL-1 and IL-1 + M-CSF.

Animals↗

PubMed1996

Enhanced platelet recovery in myelosuppressed mice treated with interleukin-1 and macrophage colony-stimulating factor: potential interactions with cytokines having megakaryocyte colony-stimulating activity.

Studies were carried out to determine whether the combination of IL-1 + M-CSF, similar to the effect of these cytokines on neutropenia, was able to reduce the duration of thrombocytopenia in the 5-fluorouracil (5-FU)-myelosuppressed mouse. In addition, comparisons were made between the in vivo effects of IL-1 + M-CSF and other "thrombopoietic" cytokines (e.g., IL-3, IL-6, and GM-CSF) that demonstrate some form of megakaryocytopoietic activity in vitro. Of the five cytokines studied, only IL-1 and IL-6, by themselves, were able to effect thrombopoietic recovery in the myelosuppressed mouse. IL-1, either when acting alone or interacting synergistically with M-CSF, was able to reduce significantly the period of thrombocytopenia, but the effects of IL-6 were restricted to enhancing platelet production during the period of rebound thrombocytopenia without altering the kinetics of thrombopoietic recovery. Moreover, none of the cytokine combinations studied were found to interact to reduce further the duration of thrombocytopenia beyond that observed with IL-1 + M-CSF. Nonetheless, IL-3, IL-6, and, to a lesser extent, GM-CSF were each able to interact with IL-1 + M-CSF to extend further the period of enhanced platelet production in the animal. However, scheduling studies suggested that these thrombopoietic cytokines interacted in sequence, rather than in concert, with IL-1 + M-CSF to enhance platelet production during thrombopoietic recovery. Furthermore, the data presented are consistent with the hypothesis that IL-1 + M-CSF initially acts on a multilineage, 5-FU-resistant target cell and that IL-6 (and possibly IL-3 and GM-CSF) serves as a secondary cytokine further to enhance platelet production during rebound thrombopoiesis in the 5-FU-treated mouse.

Animals↗

PubMed1973