Gunnar Akner

Subcellular distribution of the glucocorticoid receptor and evidence for its association with microtubules

The cellular distribution of the glucocorticoid receptor (GR) has not yet been firmly established. The extensive literature indicates that GR is present both in the cytoplasm and the cell nucleus, however, some studies have failed to detect cytoplasmic GR. It is still controversial as to whether GR is randomly diffusing in the cytoplasm and nucleus, or if the GR-distribution is organized or controlled in some way, which may be of importance for the transduction of glucocorticoid effects to cells. There is evidence that both non-activated and activated GR is associated with the plasma membrane, a number of cytoplasmic organelles and the nucleus. Both morphological and biochemical evidence show that GR is associated with microtubules during different stages of the cell cycle, i.e. GR co-localizes, co-purifies and co-polymerizes with tubulin. This indicates that GR is structurally linked to the intracellular MT-network which may be of importance in the mechanism of action of glucocorticoid hormones. The literature in this field is reviewed including the reported data on subcellular GR-localization.

Evidence for colocalization of glucocorticoid receptor with cytoplasmic microtubules in human gingival fibroblasts, using two different monoclonal anti-GR antibodies, confocal laser scanning microscopy and image analysis.

The cellular distribution of the glucocorticoid receptor (GR) in relation to the microtubule protein tubulin was studied in human gingival fibroblasts, using two different anti-GR antibodies of different Ig-classes, by indirect immunofluorescence immunocytology. Further studies were performed by confocal laser scanning microscopy and digital image analysis. The study focused on fluorochrome separation, optical sectioning, digital subtraction techniques and reconstruction of projections obtained using stacks of recorded transversal sections. The data presented further strengthens the notion of a structural colocalization between GR and cytoplasmic microtubules in human fibroblasts.

Muscle strength testing with one repetition maximum in the arm/shoulder for people aged 75 + - test-retest reliability

Objective: To investigate the reliability of a muscle strength test of the arm/shoulder in elderly people, aged 75 and older, and to compare subjects with and without previous muscle strength training experience. Design: Reliability study - test-retest. Setting: Research centre for the elderly. Main measures: One repetition maximum (1 RM) was measured using an arm/shoulder strength-training device (Pull Down, Norway). Two measurements were conducted, approximately one week apart. Results: Forty people were included in the study and 34 completed both sessions. Eleven participants had previous muscle strength training experience on the indicated device. There was a high correlation between the test sessions, r = 0.97 for both groups. The analysis of 95% limits of agreement for the mean difference was -4.3/+6.9 kg for the group without and -3.0/+6.4 kg for the group with previous experience, respectively. Conclusion: One repetition maximum evaluated by the Pull Down device seems to be a reliable and safe method for dosing and evaluating a muscle strength training programme for elderly people. The observed variation of approximately -4/+7 kg cannot be interpreted as an effect of muscle training, but is more likely an effect of learning, fluctuations in daily condition and/or motivation.

The effect of exercise of the affected foot in stroke patients-a randomized controlled pilot trial

Objective: To evaluate the effect of treatment with a portable device called Stimulo on range of motion, muscle strength and spasticity in the ankle joint and its effect on walking ability, balance, activities of daily living (ADL) and health-related quality of life in stroke patients. Design: A randomized controlled pilot study. Setting: A research centre. Subjects: Ambulatory or partly ambulatory chronic stroke patients with remaining spasticity and/or decreased range of motion in the hemiparetic leg/ankle. Interventions: Standardized and individualized programme including active and passive range of motion of the ankle with a portable device (Stimulo), performed three times a week for 30 min, over a six-week period. Main measures: Range of motion, muscle strength, spasticity, gait variables, balance, ADL and health-related quality of life. Results: Eighteen subjects were included in the study with a mean age of 75 years. The compliance rate was 94-99%. There were no significant differences between the groups. Conclusion: The study showed no significant effect of an ankle-exercise intervention programme with Stimulo. Further studies with a larger sample size are of importance before any further conclusions can be drawn.

Release of corticotropin after administration of corticotropin-releasing hormone in depressed patients in relation to the dexamethasone suppression test.

The possible hypersecretion involvement of corticotropin‐releasing hormone (CRH) in the pathophysiology of hypothalamic‐pituitary‐adrenocortical axis disturbances in patients with major depressive episode and with an abnormal dexamethasone suppression test (DST) was investigated. The corticotropin (ACTH) and cortisol response to the injection of 45 μg of synthetic human CRH at 1630 were analyzed in 24 inpatients with normal (suppressors) or abnormal (nonsuppressors) DST. The outcome of the DST was analyzed using 3 cut‐off points for the cortisol levels. The clinical assessments included two rating scales. The results showed that nonsuppressors had a significantly lower ACTH response to CRH stimulation than suppressors at all cut‐off points (calculated as net area under the curve and as the difference between the peak and the baseline level) despite no significant differences in the severity of depression.

Nutrient density and variation in nutrient intake with changing energy intake in multimorbid nursing home residents.

BACKGROUNDnThe low energy intake seen in some institutionalised elderly has led to a focus on energy dense diets. The present study aimed to investigate nutrient density in the diet of nursing home residents, and calculate how changes in energy intake affect nutrient intake.nnnMETHODSnThe investigation comprised a longitudinal observational study analysing the relation between energy and nutrient intake in a general nursing home in Sweden. Food intake was weighed for 5 days every sixth month over 1.5 years and nutrient density was calculated. The 52 multimorbid residents [mean (range) age 84 (67-102) years] with three complete 5-day weighed food records were included in the study. A mixed linear model was used to calculate changes in nutrient intake with changing energy intake.nnnRESULTSnNutrient density was adequate for vitamins A, B(12), thiamine, riboflavin and niacin, and low for vitamins D and E, folate, potassium, magnesium and iron. The mixed linear model showed that the fat-soluble vitamins, as well as folate and vitamin B(12), increased the most with increasing energy intake, whereas sodium, potassium, thiamine and selenium had the smallest increase.nnnCONCLUSIONSnNutritional density of the food should be considered when planning diets for elderly patients with poor appetite.

GLUCOCORTICOID RECEPTOR INHIBITS MICROTUBULE ASSEMBLY IN VITRO

The effect of glucocorticoid hormones, purified glucocorticoid receptor (GR) and purified heat shock protein M(r) 90,000 (hsp90) on microtubule (MT) assembly in vitro was tested by a spectrophotometric MT assembly assay and electron microscopy. GR significantly prolonged the nucleation phase, slowed down the assembly rate and reduced the maximal amplitude of MT assembly compared with control. The effects were partially reversed by the addition of glucocorticoid hormone. GR associated with MTs. These results indicate that GR affects MT assembly in vitro, which may be a functional correlate to the structural association of GR with MTs. This implies that factors affecting GR may affect MT assembly in vivo.

Immunocytochemical Studies on Glucocorticoid Receptor

Publisher Summary This chapter focuses on the immunocytochemical studies on glucocorticoid receptor (GR). The localization of the GR-immunoreactive neurons in the rat central nervous system has been studied using an anti-GR monoclonal mouse antibody, MAb 7, directed against an epitope in the N-terminal domain of the rat GR. Subjective analyses reporting various degrees of intensity/density of GR immunoreactivity can be improved by computer-assisted image analysis to provide semiquantitative microdensitometric evaluations. An in vitro study using BUGR-2 revealed the presence of GR immunoreactivity in primary cultures of mixed glial cells and within glial cell lines. Some of the discrepancies may be explained by technical circumstances such as different species, cell types, anti-GR antibodies, fixation/permeabilization procedures, and detection techniques.

The Association of the Glucocorticoid Receptor with Mr 90,000 Heat Shock Protein and Tubulin

The rat liver glucocorticoid receptor (GR) is associated with an Mr ~ 90 000 heat shock protein (hsp90) which in vitro has been shown to affect the functional status of GR. When GR is associated with a diner of hsp90 it is unable to bind to DNA. By a ligand- and temperature-dependent process GR dissociates from hsp90 and becomes functionally active, in terms of capacity to bind to specific and non-specific DNA-sequences. Hsp90 interaction with GR has been shown to require at least the presence of an intact steroid binding domain of GR. After in vitro expression of rat GR in a reticulocyte lysate system GR interacts with rabbit hsp90 preexisting in the lysate.

Adrenocorticotropin and cortisol response to lysine vasopressin in relation to the outcome of the dexamethasone suppression test in major depressive disorder

ABSTRACT— The pathophysiology behind the abnormalities of the hypothalamic pituitary adrenal cortex axis found in patients with major depressive disorder was studied by the use of the vasopressin test. The response of plasma adrenocorticotropin (ACTH) and cortisol to the injection of 10 IU lysine‐vasopressin (LVP) was investigated in 18 patients meeting the DSM‐III criteria for major depressive episode. The response was correlated to the outcome of the dexamethasone suppression test (DST) with the use of two different cut‐off points, 139 nmol/1 and 200 nmol/1 respectively.