Biomedical subjects

E Nilsson

Publications and source records attributed to E Nilsson.

At least 19 recordsLinked to original sources

PubMed2005

Toxicity identification evaluation of five metals performed with two organisms (Daphnia magna and Lactuca sativa).

When trying to identify the main toxicants in effluents, natural waters, sediments, soil leachates, and leachates from products, the Toxicity Identification Evaluation (TIE) procedure has proven useful. To enhance the use of this procedure for soil, sewage, and sediment samples, we wanted to evaluate this TIE procedure, regarding metal toxicity, for the 96-h root elongation test performed with Lactuca sativa (lettuce) seeds. We also wanted to evaluate the effect of TIE treatment on the toxicity of Mn and Fe to Daphnia magna. Bioassays were performed with Daphnia magna (48-h immobility) and lettuce seeds (96-h root elongation) to determine the effect concentrations for both organisms of Ag, Cu, Fe, Mn, and Zn. The TIE was then performed at the determined Daphnia 48-h EC(84) and Lactuca 96-h EC(50) for each metal. Our results showed that the order of the metal toxicity was Ag>Cu>Zn>Fe>Mn, for Daphnia and Ag = Zn = Fe = Cu > Mn for lettuce seeds. We also found that toxicity of the metals for Daphnia magna was reduced according to the prevailing knowledge regarding Cu, Zn, and Ag. However, the toxicity of Ag and Cu for Daphnia was also reduced by filtration through a C18 resin. Toxicity of Mn and Fe was reduced by filtration through a CM resin and increase of pH. For lettuce seeds, toxicity of the metals was reduced by the same treatments as for Daphnia magna with the exception of EDTA addition, which did not affect Cu toxicity to lettuce seeds. No effects were found for filtration through a C18 resin. We suggest that the TIE procedure using lettuce seeds can be used in toxicity identification of metals. However, the effects of pH manipulations were often stronger with lettuce and should be interpreted with care.

Animals↗

PubMed2005

Identification of metal toxicity in sewage sludge leachate.

Sewage sludge is a source of organic matter and nutrients with the potential for being used as a fertilizer. However, metals in sewage sludge might accumulate in soil after repeated sludge applications, and metal concentrations might reach concentrations that are toxic to microorganisms, soil organisms and/or plants. This toxicity might change with time due to kinetic factors or abiotic factors such as freezing, drying or rainfall. The objective of this study was to determine toxicity of sewage sludge leachate from a lysimeter with 50 cm of sludge applied. Attempts were also made to identify the cause of toxicity of the sludge leachate by toxicity identification and evaluation (TIE) techniques. Sludge leachate was collected monthly during 1 experimental year (August 2001 to August 2002). Metal concentrations were analysed, and the toxicity was determined with Daphnia magna (48-h immobility). The effect of EDTA or sodium thiosulphate addition, filtration through a CM-resin or a Millex-resin on toxicity was also tested. The results showed that toxicity of the sludge leachate apparently varied during the year, and that filtration through the CM-resin reduced most of the toxicity followed by the addition of EDTA. None of the other treatments reduced the toxicity of the sludge leachate. This indicated that one or more metals were responsible for the observed toxicity. Further calculations of toxic units (TU) suggested that Zn contributed most to the toxicity. Results also indicated that Ca concentrations in the sludge leachate reduced the toxicity of Zn.

Animals↗

PubMed2005

Presence and function of the calcitonin gene-related peptide receptor on rat pial arteries investigated in vitro and in vivo.

Calcitonin gene-related peptide (CGRP) and related peptides may be involved in migraine pathogenesis. To understand their vasomotor role in the cerebral circulation, we performed two studies, a pressurized arteriography study of the middle cerebral artery (MCA) and a genuine closed cranial window (gCCW) in vivo study. Using the pressurized arteriography model rat MCAs were mounted on micropipettes, pressurized to 85 mmHg and luminally perfused. The diameter responses to luminally and abluminally applied rat-alphaCGRP, rat-betaCGRP, amylin and adrenomedullin were compared with the resting diameter. Only abluminally applied CGRP induced dilation of the cerebral arteries; E(max) for alphaCGRP and betaCGRP were 35 +/- 0.5% and 10.8 +/- 0.2%. These responses were blocked by CGRP(8-37). The gCCW model allowed videomicroscopic visualization of the pial vessels in anaesthetized rats. Changes in vessel diameter to intravenously administered alphaCGRP and betaCGRP were compared with pre-infusion baseline. Intravenous infusion of alphaCGRP and betaCGRP in the highest dose induced dilation of the cerebral cortical pial arteries/arterioles of 40.3 +/- 7.5% and 49.1 +/- 8.4%, respectively. However, this was probably secondary to a decrease in blood pressure of 44.8 +/- 3.3 mmHg and 49.2 +/- 3.3 mmHg. Our results suggest that CGRP receptors are probably functional on the smooth muscle cells and not on the endothelium of rat cerebral arteries.

Adrenomedullin↗

PubMed2004

Type of anaesthesia and patient acceptance in groin hernia repair: a multicentre randomised trial.

BACKGROUND: Groin hernia repair can be performed under general (GA), regional (RA), or local (LA) anaesthesia. This multicentre randomised trial evaluates patient acceptance, satisfaction, and quality of life with these three anaesthetic alternatives in hernia surgery. METHODS: One hundred and thirty-eight patients at three hospitals were randomised to one of three groups, GA, RA, or LA. Upon discharge, they were asked to complete a specially designed questionnaire with items focusing on pain, discomfort, recovery, and overall satisfaction with the anaesthetic method used. The global quality-of-life instrument EuroQol was used for estimation of health perceived. RESULTS: Significantly more patients in the LA group than in the RA group felt pain during surgery ( P<0.001). This pain was characterised as light or moderate and for the majority of LA patients was felt during infiltration of the anaesthetic agent. Postoperatively, patients in the LA group first felt pain significantly later than patients in the other two groups ( P=0.012) and significantly fewer LA patients consumed analgesics more than three times during the first postoperative day ( P=0.002). The results concerning nausea, vomiting, and time to first meal all favour LA. No difference was found among the three groups concerning overall satisfaction and quality of life. CONCLUSION: In a general surgical setting, we found LA to be well tolerated and associated with significant advantages compared to GA and RA.

Adult↗

PubMed2004

Expression of serotonin receptors and role of serotonin in human prostate cancer tissue and cell lines.

BACKGROUND: Increase in the number of serotonin (5-HT) releasing neuroendocrine (NE) cells has been shown to be correlated with tumor progression, loss of androgen dependence, and poor prognosis. Serotonin is a well-known mitogen which mediates a wide variety of physiological effects via multiple receptors, of which receptor subtype 1 (5-HTR1) has been identified in prostate cancer (PC) cell lines. Recently, 5-HT has been found to show growth-promoting activity and to be functionally related to oncogenes. MATERIALS AND METHODS: Localization, protein content, and mRNA expression of 5-HTR subtype 1A, 1B, and 1D was studied in prostatic tissue (35 patients), metastases, PC cell lines, a benign prostatic stromal cell line (human prostate cell preparation (hPCP)), and xenografts of PC-3 cells by immunohistochemistry (IHC), Western blotting, and RT-PCR, respectively. The growth-inhibition effect of a 5-HT1A antagonist (NAN-190) on PC cell lines was studied using a bromodeoxyuridine (BrdU) assay. RESULTS: A strong immunoreaction of 5-HTR1A and 1B was demonstrated in high-grade tumor cells (35/35) and a small number of BPH cells, whereas 5-HTR1D was confined to vascular endothelial cells. 5-HTR1A was also demonstrated in PC cells metastasized to lymph node and bone, PC-3, DU145, LNCaP, and in xenografts of PC-3 cells and hPCP. Western blot analysis gave strong bands from PC tissue extracts compared to BPH tissue. Using RT-PCR, 5-HTR1A mRNA was demonstrated in all PC cell lines. An antagonist of 5-HTR1A (NAN-190) inhibited the growth of PC-3, DU145, and LNCaP cells but not of hPCP cells. CONCLUSIONS: This is the first study demonstrating an overexpression of 5-HTR subtypes 1A and 1B in PC cells, especially in high-grade tumors. Moreover, 5-HT stimulates proliferation of PC cells and 5-HTR1A antagonists inhibit proliferation. Thus, we propose that 5-HT has an important role in tumor progression, especially in the androgen-independent state of the disease. The design of specific antagonists for this type of receptor might be useful for the growth control of androgen-independent tumors.

Blotting, Western↗

PubMed2004

Estimation of genetic and environmental factors for binary traits using family data.

While the family-based analysis of genetic and environmental contributions to continuous or Gaussian traits is now straightforward using the linear mixed models approach, the corresponding analysis of complex binary traits is still rather limited. In the latter we usually rely on twin studies or pairs of relatives, but these studies often have limited sample size or have difficulties in dealing with the dependence between the pairs. Direct analysis of extended family data can potentially overcome these limitations. In this paper, we will describe various genetic models that can be analysed using an extended family structure. We use the generalized linear mixed model to deal with the family structure and likelihood-based methodology for parameter inference. The method is completely general, accommodating arbitrary family structures and incomplete data. We illustrate the methodology in great detail using the Swedish birth registry data on pre-eclampsia, a hypertensive condition induced by pregnancy. The statistical challenges include the specification of sensible models that contain a relatively large number of variance components compared to standard mixed models. In our illustration the models will account for maternal or foetal genetic effects, environmental effects, or a combination of these and we show how these effects can be readily estimated using family data.

Cluster Analysis↗

PubMed2004

Chronic pain after open mesh and sutured repair of indirect inguinal hernia in young males.

BACKGROUND: Chronic pain is common after herniorrhaphy, but the effect of surgical technique (mesh versus non-mesh repair) and the social consequences of the pain have not been established. The aim of this study was to analyse chronic postherniorrhaphy pain and its social consequences in young males operated on for an indirect inguinal hernia with a Lichtenstein mesh repair, Shouldice or Marcy (annulorrhaphy) repair. METHODS: This was a postal questionnaire study carried out within the Danish and Swedish Hernia Database Collaboration. Some 2612 patients responded (response rate 80.9 per cent), of whom 1250 had undergone a Lichtenstein, 630 a Shouldice and 732 a Marcy repair. RESULTS: Chronic pain had been experienced within the previous month by 22.9 per cent of the patients who responded. There was an overall decrease in pain with time, from 29.7 per cent at 6-12 months to 18.1 per cent at 37-48 months after surgery, with no overall differences between the three types of repair. Pain was more common in patients younger than 40 years of age. Some 3.9 per cent of patients described the pain as moderate to severe and as frequent or constant. Of all patients with pain, 10.7 per cent experienced it as worse after than before surgery, and 56.6 per cent stated that it interfered with social activities. CONCLUSION: Chronic pain is common after primary inguinal hernia repair in young males, but there is no difference in the pain associated with open mesh and non-mesh repair.

Adolescent↗

PubMed2004

Relationships between platelets and inflammatory markers in rheumatoid arthritis.

AIM OF THE STUDY: To investigate platelets and different inflammatory markers in conjunction with a substantial inflammatory reaction. We used individuals with active rheumatoid arthritis (RA) as an experimental cohort. METHODS: We selected 16 patients with active RA having at least one affected joint. On day 1, platelet and neutrophil counts together with C-reactive protein (CRP) were determined. We further analysed platelet volume (MPV) and plasma levels of thrombopoietin (TPO), P-selectin, myeloperoxidase and interleukin 6 (IL-6). After 2 years when all patients failed to show any swollen joints all analyses were repeated. RESULTS AND CONCLUSIONS: As expected platelet count, CRP and IL-6 were elevated in active RA. The measures correlated with each other thus reflecting the same characteristic of the inflammatory response. The neutrophil count, MPV and myeloperoxidase also mirror disease activity. They failed to correlate with other activity markers thus providing unique information. MPV and myeloperoxidase on day 1 correlated with recovery values. Therefore, they could be suitable to use when following the inflammatory reaction over a long period of time.

Arthritis, Rheumatoid↗

PubMed2004

Abdominal pain and patient overall and cosmetic satisfaction one year after cholecystectomy: outcome of a randomized trial comparing laparoscopic and minilaparotomy cholecystectomy.

BACKGROUND: Previous studies with long-term follow-up after cholecystectomy have shown that residual abdominal symptoms are common. Laparoscopic cholecystectomy (LC) and minilaparotomy cholecystectomy (MC) can both give a smoother, early postoperative course than conventional open cholecystectomy (OC). The present study concerns abdominal pain and patient overall and cosmetic satisfaction one year after LC and MC. METHODS: In a prospective, single-blind study, 724 patients were randomly allocated to LC or MC. Patients completed questionnaires including items concerning abdominal pain before and one year after surgery and overall and cosmetic satisfaction one year after surgery. RESULTS: There was no difference in reduction of abdominal pain between LC and MC patients. For four different aspects of abdominal pain, 31%, 24%, 30% and 16% of patients operated with LC reported residual abdominal pain one year after surgery. The corresponding figures for MC were 28%, 20%, 27% and 18% (P values 0.55, 0.32, 0.55 and 0.63, respectively). According to questionnaire answers, there was no significant difference in the cosmetic result and overall patient satisfaction between LC and MC patients. CONCLUSIONS: There are no differences between laparoscopic and minilaparotomy cholecystectomy in long-term outcome regarding abdominal pain and patient overall and cosmetic satisfaction. A large proportion of patients have abdominal pain one year after cholecystectomy. Future studies should include preoperative assessment and indications for cholecystectomy.

Abdominal Pain↗

PubMed2004

Analysis of ET-A and ET-B receptors using an isolated perfused rat lung preparation.

AIMS AND METHODS: The pulmonary and vascular effects of endothelin-1 receptor activation were studied in isolated perfused and ventilated lung preparations from rat. The responses to endothelin-1 (ET-1) and the endothelin B (ET(B)) receptor agonist sarafotoxin 6c (S6c) were characterized using the endothelin A (ET(A))-receptor antagonist FR 139317, the ET(B)-receptor antagonist BQ 788 and the combined ET(A)/ET(B)-receptor antagonist Bosentan. The respiratory parameter airway conductance (G(aw)) and the vascular parameter perfusion flow were analysed simultaneously. RESULTS: Concentration-response curves for ET-1 administered intra-arterially revealed that its most potent effect was on the vascular side while S6c had a more potent effect on airway conductance. ET-1, given as a bolus dose intra-arterially (100 microL of 0.2 nM), induced a strong- and long-lasting contraction of the vasculature while only a less pronounced contraction was seen in the airways. Neither of the antagonists had a significant effect per se on G(aw) or perfusion flow. FR 139317 reduced the effect of ET-1 on perfusion flow by about 50%, while airway conductance was augmented. BQ 788 enhanced the decrease in perfusion flow by ET-1 while G(aw) was not influenced. The combined ET(A)/ET(B) antagonist Bosentan powerfully prevented the ET-1-induced decrease in G(aw) but did not alter its reduction in perfusion flow. CONCLUSIONS: The potent effect of ET-1 on the vascular side of the lung is mediated mainly through ET(A) receptors, whereas both ET(A) and ET(B) receptors are involved in G(aw) in the rat lung.

Animals↗

PubMed2004

Lameness in piglets. Abrasions in nursing piglets and transfer of protection towards infections with Streptococci from sow to offspring.

A group of 175 newborn piglets were monitored with respect to development of abrasions and lameness. Lameness was diagnosed in 10.9% of the piglets. About every second litter was affected and around 75% of these diagnoses took place during the first 3 weeks of life. Skin lesions were present already on day 3. They increased in magnitude until day 10 and thereafter declined. They were generally bilateral and most commonly observed as abrasions over the carpal joints. Hocks, face and tails were affected in a similar way, but at lower magnitudes. Sole bruising was observed in 87% of the piglets on the third day of life, and moderate to severe lesions dominated until day 10. Thereafter the incidence decreased, indicating healing with time. Still 39% of the piglets were affected at day 17. There was a significant positive correlation between skin lesions of carpus and hock within all examination days in selected piglets with known identity (n = 48). Between day 10 and 17 significant positive correlations were found within all examination sites with exception of abdomen and teats. The offspring of sows treated against mastitis expressed more abrasions then piglets delivered by healthy sows and the mortality during the first 17 days postpartum was significantly higher among piglets delivered by sows treated for mastitis. The level of serum antibodies to Streptococcus equisimilis in eight dams decreased during the last month of gestation and a declining maternal immunity to S. equisimilis was demonstrated in all piglets (n = 47) during the first 5 weeks of life. During the first 2 weeks of life somewhat lower median levels of serum antibodies were recorded among the piglets that were treated against arthritis (n = 8).

Animals↗

PubMed2003

Influence of suture material and surgical technique on risk of reoperation after non-mesh open hernia repair.

BACKGROUND: Although mesh techniques are used with increasing frequency, sutured repair still has a place in groin hernia surgery. Studies relating suture material to recurrence rate have yielded conflicting results. The aim of the present study was to analyse the influence of suture material and sutured non-mesh technique on the risk of reoperation in open groin hernia repair using data from the Swedish Hernia Register. METHODS: The relative risk of reoperation after sutured repair using non-absorbable, late absorbable and early absorbable sutures was compared in multivariate analyses, taking into account known confounding factors. RESULTS: Between 1992 and 2000, 46,745 hernia repairs were recorded in the Swedish Hernia Register. Of these, 18,057 repairs were performed with open non-mesh methods and were included in the analysis. Using non-absorbable suture as reference, the relative risk of reoperation after repair with early absorbable suture and late absorbable suture was 1.50 (95 per cent confidence interval (c.i.) 1.22 to 1.83) and 1.03 (95 per cent c.i. 0.83 to 1.28) respectively. Using the Shouldice repair as reference, other sutured repairs were associated with a significantly higher relative risk of reoperation (1.22, 95 per cent c.i. 1.03 to 1.44). CONCLUSION: A non-absorbable or a late absorbable suture is recommended for open non-mesh groin hernia repair. The Shouldice technique was found to be superior to other open methods.

Adolescent↗

PubMed2003

Post-thoracotomy pain after thoracic epidural analgesia: a prospective follow-up study.

BACKGROUND: Pain becomes chronic in 22-67% of patients who undergo a thoracotomy. Thoracic epidural analgesia (TEA) has replaced less invasive methods to manage postoperative pain. We wanted to find out if active use of TEA, combined with extended pain management at home, reduces the incidence of chronic post-thoracotomy pain. METHODS: All consecutive thoracotomy patients during a 16-month period were included. On the ward, pain was measured daily by VAS during rest and coughing and the consumption of analgesics was registered. The patients were interviewed one week after discharge by telephone and by a questionnaire after 3 and 6 months to find out how much pain they had. RESULTS: A total of 114 patients were recruited. The data were analysed from 89 patients who had had TEA and 22 who had had other methods. TEA was effective in alleviating pain at rest and during coughing. In the TEA patients the incidence of chronic pain of at least moderate severity was 11% and 12% at 3 and 6 months, respectively. One week after discharge 92% of all patients needed daily pain medication. CONCLUSIONS: TEA seems effective in controlling evoked postoperative pain, but technical problems occurred in 24% of the epidural catheters. The incidence of chronic pain was lower compared with previous studies where TEA was not used. The patients had significant pain and needed regular pain medication and instructions during the first week after discharge. Extended postoperative analgesia up to the first week at home is warranted.

Adult↗

PubMed2002

Cognitive performance in very old diabetic persons: the impact of semantic structure, preclinical dementia, and impending death.

The authors examined the associations of diabetes mellitus with cognitive performance in a population-based sample of nondemented and nondepressed very old persons. Diabetic participants (n = 31) were compared with nondiabetic controls (n = 307), adjusting for age, educational level, and related vascular diseases and signs. Results showed that diabetic persons performed significantly worse on tests of verbal fluency and episodic memory but that the effects on both types of abilities were less pronounced in tasks involving higher degrees of semantic structure. Follow-up analyses further revealed that preclinical dementia and impending death accounted for much of the observed associations. The results suggest that cognitive deficits among very old diabetics are most likely detected by tasks that draw less on semantic structures and that the most robust effects may be found in letter fluency performance.

Aged↗

PubMed2001

Synthesis of gamma-carboxylated polypeptides by alpha-cells of the pancreatic islets.

gamma-Carboxylated proteins were detected in normal human pancreas by immunohistochemistry with a monoclonal antibody (M3B) specific for gamma-carboxyglutamyl residues. Staining appeared to be localized to the glucagon-secreting alpha-cells in the islets of Langerhans. Consistent with this, sections from a glucagonoma were stained much more intensely with the M3B antibody than those from an insulinoma. A murine alpha-cell line (alphaTC1 Clone 9) was cultured and gamma-carboxylated polypeptides, identified immunologically as prothrombin, protein S and (tentatively) Gas6, were isolated from the intracellular compartment by chromatography on an M3B-coupled resin. As in liver, prothrombin is synthesized by alpha-cells as a gamma-carboxylated zymogen that can be cleaved by ecarin to form an active serine protease that is inhibited by hirudin. The pancreas thus appears to be a novel site of synthesis for certain vitamin K-dependent proteins.

1-Carboxyglutamic Acid↗

PubMed2001

Basic fibroblast growth factor induces primordial follicle development and initiates folliculogenesis.

The recruitment of primordial follicles to initiate folliculogenesis determines the population of developing follicles available for ovulation and directly regulates female reproductive efficiency. In the current study, a floating organ culture system was used to examine the progression of primordial (stage 0) follicles to developing (stages 1-4) follicles in 4-day-old pre-pubertal rat ovaries. Basic fibroblast growth factor (bFGF) was found to induce primordial follicle development similar to what has been demonstrated for kit ligand/stem cell factor (KL). The bFGF-treated ovaries contained 85% developing follicles compared with 50% developing follicles for control untreated organ cultures. Correspondingly, the number of primordial follicles in bFGF-treated ovaries decreased to 15% of the total compared with 45% for controls. A bFGF neutralizing antibody was found to decrease the small amount of spontaneous follicle development that occurs during the organ culture. Basic FGF was localized to primordial and early developing follicles by immunocytochemistry and was primarily observed in the oocytes. Treatment of bovine ovarian theca cells and stroma cells with bFGF was found to promote cell growth. Basic FGF produced by the oocyte in early stage follicles appears to act on adjacent somatic cells to promote cell growth and development. Basic FGF, like KL, appears to be a primordial follicle-inducing factor. In summary, bFGF can regulate primordial follicle development that directly influences female reproductive efficiency.

Animals↗

PubMed2001

Stromal-epithelial interactions in the progression of ovarian cancer: influence and source of tumor stromal cells.

Stromal cells are essential for the progression of many cancers including ovarian tumors. Stromal cell-epithelial cell interactions are important for tumor development, growth, angiogenesis, and metastasis. In the current study, the effects of normal ovarian bovine stromal cells on ovarian tumor progression was investigated. The hypothesis tested is that ovarian stromal cells will alter the onset and progression of ovarian tumors. Conditioned medium from normal bovine ovarian surface stromal cells was found to stimulate the growth of normal ovarian surface epithelium and had no effect on the growth of human tumor cell lines SKOV3 and OCC1. Human ovarian cancer cell lines, SKOV3 and OCC1, were injected subcutaneously into nude mice to examine tumor progression. Tumor growth in the nude mice was dramatically reduced when normal ovarian surface stromal cells were co-injected with SKOV3 or OCC1 cells. Similar results were obtained with normal bovine or human ovarian stromal cells. In contrast, irrelevant testicular stromal cells and epithelial cells had no effect on tumor growth in the nude mouse. Histological examination of these tumors revealed a characteristic stromal cell component adjacent to epithelial cell colonies. Sections of these tumors were hybridized with species specific genomic probes using fluorescence in situ hybridization to identify cell populations. Epithelial cells were shown to be of human origin (i.e. SKOV3 or OCC1), but stromal cells were found to be primarily murine in origin (i.e. host tissue). No detectable bovine cells were observed in the tumors after one week post-injection. Results suggest that stromal cells are an essential component of ovarian tumors. Interestingly, normal ovarian stromal cells had the ability to inhibit tumor growth, but were not able to survive long-term incubation at the tumor site. The developing tumor appears to recruit host (i.e. murine) stromal cells to invade the tumor and support its growth. In summary, normal ovarian stromal cells can inhibit ovarian tumor progression and the developing tumors recruit adjacent host stroma to become "tumor stroma". The tumor stroma likely develop an altered phenotype that cooperates with the tumorigenic epithelial cells to help promote the progression of ovarian cancer.

Animals↗

PubMed2001

Insulin can enhance GLUT4 gene expression in 3T3-F442A cells and this effect is mimicked by vanadate but counteracted by cAMP and high glucose--potential implications for insulin resistance.

UNLABELLED: It is well-established that high levels of cAMP or glucose can produce insulin resistance. The aim of this study was to characterize the interaction between these agents and insulin with respect to adipose tissue/muscle glucose transporter isoform (glucose transporter 4, GLUT4) gene regulation in cultured 3T3-F442A adipocytes and to further elucidate the GLUT4-related mechanisms in insulin resistance. Insulin (10(4) microU/ml) treatment for 16 h clearly increased GLUT4 mRNA level in cells cultured in medium containing 5.6 mM glucose but not in cells cultured in medium with high glucose (25 mM). 8-Bromo-cAMP (1 or 4 mM) or N(6)-monobutyryl cAMP, a hydrolyzable and a non-hydrolyzable cAMP analog, respectively, markedly decreased the GLUT4 mRNA level irrespective of glucose concentrations. In addition, these cAMP analogs also inhibited the upregulating effect of insulin on GLUT4 mRNA level. Interestingly, the tyrosine phosphatase inhibitor vanadate (1-50 microM) clearly increased GLUT4 mRNA level in a time- and concentration-dependent manner. Furthermore, cAMP-induced inhibition of the insulin effect was also prevented by vanadate. In parallel to the effects on GLUT4 gene expression, both insulin, vanadate and cAMP produced similar changes in cellular GLUT4 protein content and cAMP impaired the effect of insulin to stimulate (14)C-deoxyglucose uptake. In contrast, insulin, vanadate or cAMP did not alter insulin receptor (IR) mRNA or the cellular content of IR protein. IN CONCLUSION: (1) Both insulin and vanadate elicit a stimulating effect on GLUT4 gene expression in 3T3-F442A cells, but a prerequisite is that the surrounding glucose concentration is low. (2) Cyclic AMP impairs the insulin effect on GLUT4 gene expression, but this is prevented by vanadate, probably by enhancing the tyrosine phosphorylation of signalling peptides and/or transcription factors. (3) IR gene and protein expression is not altered by insulin, vanadate or cAMP in this cell type. (4) The changes in GLUT4 gene expression produced by cAMP or vanadate are accompanied by similar alterations in GLUT4 protein expression and glucose uptake, suggesting a role of GLUT4 gene expression for the long-term regulation of cellular insulin action on glucose transport.

3T3 Cells↗