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Biomedical subjects

A Fusco

Publications and source records attributed to A Fusco.

At least 271 records · Page 15Linked to original sources
PubMed1981

Analysis of the myeloproliferative sarcoma virus genome: limited changes in the prototype lead to altered target cell specificity.

The myeloproliferative sarcoma virus (MPSV) derived from Moloney sarcoma virus (MSV-Mol) is a unique sarcoma virus which causes expansion of the hematopoietic stem cell compartment as well as the erythroid and myeloid cell lineages. MPSV also induces spleen focus formation in adult mice as do Friend and Rauscher viruses. Analysis of the MPSV genome on methyl mercury gels showed that the genome size is 7.0 kilobases, which is larger than the defective genome of any known MSV-Mol isolate. Hybridization analysis with specific cDNA probes showed that MPSV is a modified sarcoma virus with no sequences in the unique region of the defective sarcoma genome related to unique Friend virus sequences. The only viral sequences in the defective genome other than helper virus-related sequences are derived from the Moloney sarcoma virus genome with no new cellular sequences added. There was no evidence for induction of xenotropic virus sequences in MPSV-infected spleens of DBA/2J mice, indicating that spleen focus formation can be obtained by different mechanisms.

Animals↗
PubMed1980

Insulin antibodies prevent insulin-receptor interactions.

The study was carried out to investigate whether insulin bound to antibody is able to bind the insulin receptor of target tissues. Three specific rabbit anti-insulin sera as well as sera from eight diabetic patients with insulin antibodies were incubated, free of insulin, with labelled insulin for 48 h at 4 degrees C; following incubation labelled insulin was employed in binding experiments on monocytes, erythrocytes and placenta membranes. Using rabbit sera, receptor binding was absent when insulin was totally combined with antibody, and appeared in increasing amounts as the percentage of free insulin increased to reach a maximum when no insulin was combined with antibody. The same experiment using sera from diabetic patients showed a close negative relationship (r = 0.95) between the amount of insulin bound to the antibody and the amount bound to receptors. The influence of the insulin-antibody complex on the insulin receptor interaction was evaluated by exposing the insulin-antibody complex to the receptor in pH, temperature and competition-inhibition curve experiments. The complex had no effect on receptor affinity or on the pH and temperature relationship influence with insulin-receptor interaction. The findings suggest that insulin resistance in the presence of insulin antibodies is due only to an alteration occurring before the interaction of insulin with its receptor, and demonstrate that the insulin-antibody complex does not influence the insulin receptor interaction.

Binding, Competitive↗
PubMed1980

Differences in insulin receptors between men and menstruating women and influence of sex hormones on insulin binding during the menstrual cycle.

Specific binding of [125I]insulin to circulating monocytes and erythrocytes from nine normal menstruating women and nine normal men was determined during a 28-day period (one sample every 7 days). In women, insulin binding was higher to both monocytes (P less than 0.001) and erythrocytes (P less than 0.02) in the follicular phase than in the luteal phase. In men, insulin binding to monocytes was similar to the follicular phase values for women; however, insulin binding to erythrocytes from men showed higher values than insulin binding to erythrocytes from women in both the follicular (P less than 0.001) and luteal (P less than 0.001) phases. These differences were due primarily to changes in receptor concentration rather than receptor affinity. An inverse relationship was found between insulin binding to monocytes and levels of 17 beta-estradiol, progesterone, and 17 alpha-hydroxyprogesterone; this relationship was not observed in insulin binding to erythrocytes. The present data, therefore, suggest that sex hormones may play a role in the control of insulin receptors. Furthermore, it appears that other factors exist during the follicular phase that lower insulin binding to erythrocyte insulin receptors. If insulin receptors on circulating cells reflect the behavior of the main insulin target tissues, the present data might in part explain the reduction in glucose tolerance reported by various authors in the second half of the menstrual cycle.

Adult↗
PubMed1980

Effect of dexamethasone and cortisone on insulin receptors in normal human male.

Results of a recent study suggested that depending upon the glucocorticoid or the model used, opposite changes occur in insulin binding; in fact, the increase in insulin receptor number on monocytes after prednisone ingestion in man appears to contrast with previous reports in animals in which a decrease was shown after dexamethasone. To establish whether this apparent discrepancy depends upon the model used in human studies (i.e. monocytes), the effect of dexamethasone and corticone intake on normal men was evaluated. A significant decrease was observed in insulin binding on circulating monocytes 24, 48, and 72 h after both steroids, mainly due to reduced receptor affinity. Furthermore, steroid treatment increased insulinemia which did not appear to be related to insulin binding. These data are in agreement with results in animal studies and appear to suggest that previous data on prednisone do not depend upon the model used (i.e. monocytes) but upon the hormone itself, thus indicating that glucocorticoids, depending upon their chemical structure, may produce opposite changes in membrane insulin binding sites. Furthermore, since dexamethasone and cortisone affect plasma insulin levels in the same fashion as previously reported with prednisone, it is suggested that the variation in insulin binding observed after glucocorticoid treatment is not due to variations in insulinemia.

Cortisone↗
PubMed1980

Insulin receptors on monocytes and erythrocytes from obese patients.

Insulin receptors were studied in monocytes and erythrocytes [red blood cells (RBC)] isolated from 15 normal and 15 nondiabetic obese outpatients on an unrestricted diet. Insulin binding on both monocytes (P < 0.001) and RBC (P < 0.01) was higher in normal than in obese subjects due to different receptor concentrations. In some obese patients, binding to monocytes was decreased, while binding to RBC was normal. These data demonstrate that obese out-patients on an unrestricted diet have a reduced number of insulin receptors. It is suggested that interpretation of insulin binding based upon RBC should be used with caution, since a discrepancy exists in some subjects in the results obtained with these cells and monocytes.

Adult↗
PubMed1980

Erythrocyte insulin receptors in non-insulin-dependent diabetes mellitus.

Insulin binding was studied on circulating erythrocytes isolated from 12 normal and 12 untreated, adult, nonobese, nonketotic, non-insulin-dependent diabetic subjects. Insulin binding in normal subjects was higher than in diabetics (P less than 0.01); binding variation was caused mainly by a reduction in insulin receptor concentration. Insulin binding was inversely correlated with fasting serum insulin levels (R = 0.49; P less than 0.01). The close agreement between the present data and previous data on other cell populations suggests that isolated erythrocytes may be a useful tool in clinical investigations on the human insulin receptor.

Diabetes Mellitus↗
PubMed1980

Relationship between depression and self-contact.

To study the relationship between depression and self-contact, 25 male subjects between 30 and 35 yr. of age were administered Zung's Depression Questionnaire and measured for duration of self-contacts in a group situation and during the completion of a questionnaire on contact. Positive correlations of .73, .78, and .66 were obtained between duration of self-contact and depression score.

Adult↗
PubMed1980

Arginine does not influence insulin binding on circulating monocytes.

Glucose ingestion, food intake or acute exercise produced rapid variations in insulin binding on monocytes. Insulin seems to play a minor or any role in this phenomenon in contrast pancreatic glucagon might be involved since it usually rises when an increase in insulin receptor affinity has been observed. To investigate the role of pancreatic glucagon we have studied the effect of arginine infusion on monocyte insulin receptor in five normal subjects. Results indicate that the aminoacid employed does not induce any change in insulin receptor affinity and concentration suggesting that the simultaneous increase in plasma insulin and pancreatic glucagon levels does not exert any action.

Adult↗
PubMed1979

Aggregation-induced stability of dexamethasone receptors in rat kidney.

The stability of the dexamethasone-receptor complex of rat kidney cytosol was studied using homogenizing media of varying pH and composition. It was found that the complex is less stable with buffers usually employed for the study of steroid receptors such as Tris, EDTA etc., whereas the stability increases considerably with a solution composed of monothioglycerol 12 mmol/l and glycerol 5% in distilled water. Sepharose 4-B column chromatography revealed that the increased stability was associated with a larger form (probably an aggregate) of the receptor-steroid complex.

Animals↗
PubMed1978

Insulin receptors during the menstrual cycle in normal women.

Specific binding of 125I-insulin to circulating monocytes from eight normal menstruating women, four postmenopausal women and four men were studied four times during a 28-day period (one sample at 7-day intervals). Data indicate the presence of a higher specific cell binding fraction in the follicular phase compared to the luteal phase due to changes in insulin receptor concentration. No changes were observed in men or postmenopausal women during the same period of time suggesting that sex hormones should be included among the factors influencing insulin receptors.

Adult↗