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Biomedical subjects

S Ettinger

Publications and source records attributed to S Ettinger.

At least 19 recordsLinked to original sources
PubMed2001

Short-term 17-beta-estradiol administration does not affect metabolism in young males.

We have previously demonstrated that females oxidize more lipid and less protein and carbohydrate during endurance exercise [21]. Several studies in male rats have demonstrated similar metabolic changes after 4 d of 17-beta-estradiol (E2) administration. Our purpose was to study the effects of E2 administration upon substrate metabolism during 90min of cycle ergometry at 60% VO2peak in 11 healthy, young males. E2 was administered in a single-blind, cross-over, randomized fashion for 11 d (100 microg.d(-1) x 3.5d --> 200 microg.d(-1) x 3.5 d --> 300 microg.d(-1) x 4.0 d). Respiratory exchange ratio (RER), VO2, Ve, HR, lactate, and glucose were measured every 30 min during exercise and E2, testosterone TEST, glycerol and triglycerides were measured prior to exercise T = 0 min. Muscle biopsies were taken from the vastus lateralis before and after exercise for glycogen determination. Estradiol treatment resulted in lower plasma TEST (20.8-->7.8 nmol.L(-1), P<0.0001) and higher plasma E2 (168.1 327.3 pmol.L(-1), P < 0.002). Therewere no effects of E2 treatment upon any of the other measured variables including muscle glycogen: (E2 - PRE = 529.3 --> POST = 237.9; PL-PRE = 582.2 --> POST = 262.4 mmol.kg(-1) [dm]). We concluded that short-term E2 treatment increased plasma E2 to female follicular levels in males but had no effect upon lipid or carbohydrate metabolism.

Adolescent↗
PubMed1998

Downstream signalling events regulated by phosphatidylinositol 3-kinase activity.

The phosphatidylinositol (PI) 3-kinase family of enzymes is now known to be regulated by several different upstream pathways in response to virtually all growth factors and cytokines. In the past few years, the phosphoinositides phosphorylated at the 3-OH position of the inositol ring have been shown to be lipid second messengers that may directly or indirectly regulate the activity of several different serine/threonine kinases. Consistent with the many different cellular events in which PI 3-kinase plays an important role, a diverse group of serine/threonine kinases are regulated downstream of PI 3-kinases, including protein kinase C (PKC) isoforms, p70 S6 kinase, and PKB/Akt. This review summarises studies done primarily in the past few years that have begun to unravel these targets of PI 3-kinase activity.

Animals↗
PubMed1997

Lack of correlation between growth of TF-1 cells and tyrosine phosphorylation signals in response to IL-3, IL-5 and GM-CSF.

The human cell line, TF-1, was used to compare responses to interleukin 3 (IL-3), IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF). TF-1 cells grew well in the presence of any one of the cytokines in early passages. However, the level of tyrosine phosphorylation was minimal in response to IL-5, and detection of a tyrosine phosphorylation signal required high concentrations of IL-5. When grown for longer periods of time in the presence of one of the cytokines, there were dramatic difference in the cells' responses. IL-3 or GM-CSF-grown cells showed only half of the original bioassay response to IL-5. However, cells grown in IL-5 alone kept the same response, and all cells showed the same response to IL-3 and GM-CSF. IL-5-grown cells also had an increased tyrosine phosphorylation signal, along with increased sensitivity to IL-5, yet there was no difference in an IL-5 bioassay. The relative level of detection of tyrosine phosphorylated JAK-2, STAT-5, SHC, and other substrates corresponded to the overall tyrosine phosphorylation signal. IL-5-grown cells had approximately 10-fold more IL-5 receptor alpha subunit message compared to IL-3-grown. These results suggest that response of TF-1 cells to IL-5 may be deceiving in that a good response in a bioassay can be observed with relatively little tyrosine phosphorylation, but an increase in tyrosine phosphorylation can be correlated with an increase in the expression of IL-5 receptor alpha subunit.

Cell Division↗
PubMed1994

Chromosomal fragility associated with familial Alzheimer's disease.

To test whether chromosomal instability is associated with familial Alzheimer's disease, we examined breakage on X chromosomes of fibroblasts derived from patients with familial Alzheimer's disease, using gene cotransfer methodology. The X chromosome is a convenient target for analyzing DNA breakage because of its numerous markers and ease of selection in rodent-human hybrid cells. Patients with familial Alzheimer's disease, including the large Nova Scotia Alzheimer's kindred, show a significantly lower cotransfer of the X-linked glucose-6-phosphate dehydrogenase (G6PD) gene with the selected HPRT gene in hybrid cells, indicating breakage between the markers. Lower cotransfer of the more distant X-linked gene, MIC-2, was statistically significant in this kindred, but not in other patients with familial Alzheimer's disease. The distance between MIC2 and HPRT is sixfold to ninefold greater than that between HPRT and G6PD, suggesting that there may be a "hot spot" for breakage in the latter interval on the X chromosome of patients with familial Alzheimer's disease. The somatic cell hybrid model provides insights into underlying mechanisms for chromosomal breakage induced by the Alzheimer defect. A hypothesis implicating a candidate gene, C1-THF synthase, in the generation of chromosome instability in the pathogenesis of familial Alzheimer's disease, is presented.

12E7 Antigen↗
PubMed1991

Dichloroacetate reduces sympathetic nerve responses to static exercise.

Lactic acid is thought to be a stimulant of muscle metaboreceptors. The goal of the present study was to determine if inhibition of lactic acid production by dichloroacetate (DCA) would attenuate muscle sympathetic nerve activity (MSNA) during static forearm exercise. DCA increases pyruvate dehydrogenase levels. Thus, for a given amount of pyruvate produced, less lactic acid is formed. Seven subjects performed static forearm exercise at 20% maximal voluntary contraction until fatigue followed by posthandgrip circulatory arrest (PHG-CA) (trial.1). Subjects then received DCA (35 mg/kg) and repeated the exercise protocol (trial 2). We observed an attenuated rise in forearm venous lactate and MSNA. The trial 2 MSNA value during PHG-CA was 51 +/- 11% less than the value during trial 1 (P less than 0.01). In seven control subjects, two bouts of static forearm exercise were performed with an intervening saline infusion. This intervention had no effect on lactate or MSNA responses to exercise. We conclude that DCA attenuates lactate responses to static exercise, and this is associated with a blunted MSNA response.

Adult↗
PubMed1990

The effects of group therapy on siblings of pediatric oncology patients.

The stress and psychological difficulties of siblings of children with cancer is well documented. Siblings must cope with a myriad of emotions, isolation from the family, and many changes in daily life. Therefore, a need exists to determine the effects of psychosocial interventions on siblings of cancer patients. The support group is one psychosocial intervention that has been suggested as a method to relieve stress and enhance coping. A quasi-experimental design was selected to determine the effects of participation in a support group on the social adjustment of siblings of children with cancer. Conclusions suggest that a support group provides siblings with the opportunity to decrease their sense of isolation, ventilate negative feelings, and learn from each other. Additionally, descriptive data suggest a need for ongoing follow-up with siblings to help them manage the stresses emerging from the impact of the diagnosis and treatment on the family. Implications of this study suggest that nurses should organize support groups for siblings and/or refer them to existing groups. Also, this study suggests the need to work with siblings and educate parents regarding sibling concerns.

Adolescent↗
PubMed1989

Effects of group therapy on parents of children with cancer.

Group therapy for parents of children with cancer has been suggested as a means of relieving stress. This quasi-experimental study sought to determine the effect of participation in a support group for parents of children aged 10 to 14 years with cancer. Parents completed the Wallston Health Locus of Control (HLOC) Scale and the Social Adjustment Scale-Self Report (SAS-SR) both before and following seven group sessions. Descriptive data were collected from the cotherapists' process log and the participants' evaluation. A significant t test score (P = .017) was obtained for the HLOC Scale questionnaire. The group process log showed recurrent themes of helplessness and powerlessness. The Parent Support Group Evaluation (PSGE) developed by the researchers, demonstrated satisfaction and revealed that school and community activities were considered the most helpful. Tentative conclusions support the value of such a group in providing a forum for the parents to discuss concerns and decrease their sense of isolation. However, more study is needed with a larger sample before definitive conclusions can be reached.

Adult↗