Cartilage evaluation in finger joints in healthy controls and early hand osteoarthritis patients using high-resolution MRI.

OBJECTIVE: To compare direct evaluation of cartilage with high resolution MRI (hrMRI) to indirect cartilage evaluation using MRI inter-bone distance in hand OA patients and healthy controls. DESIGN: 41 hand OA patients and 18 healthy controls underwent hrMRI of the 2nd and 3rd metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints. The images were read by two independent readers using OMERACT hand OA MRI inter-bone distance score (0-3 scale) and a new hrMRI cartilage score with direct evaluation of the cartilage (0-3 scale). Inter-reader and intra-reader reliability was calculated using exact and close agreement and kappa values. The prevalence of abnormal scores and agreement between methods was assessed in both hand OA patients and healthy controls. RESULTS: The intra- and inter-reader reliability of both scores was comparable, with exact agreement in 73-83% and close agreement in 95-100%. In hand OA patients 27% of 161 joints had both cartilage damage and loss of inter-bone distance, cartilage damage by hrMRI only was present in 20% of joints and reduced inter-bone distance only in 4% of joints. In the healthy controls, 1 of 71 joints were scored as abnormal by both hrMRI and inter bone distance scoring, 1 joint was scored as abnormal using the hrMRI cartilage score only, whereas 15% of joints had only reduced inter bone distance. CONCLUSIONS: Direct cartilage evaluation of MCP and PIP joints using hrMRI has a good reliability, and the higher prevalence of hrMRI cartilage damage in hand OA patients and the lower prevalence in healthy controls in comparison to evaluation of inter-bone distance suggests a better validity.

Systematic review of treatments for diabetic peripheral neuropathy.

AIM: To evaluate treatment options for neuropathic pain and sensory symptoms resulting from diabetic peripheral neuropathy of the feet. METHODS: The databases PubMed, Embase and Web-of-Science were searched for randomized controlled trials, published in the period from database inception to 2 July 2015, that evaluated treatments for diabetic peripheral neuropathy of the feet with placebo or standard treatment as comparators. Participants in these trials included people with diabetes mellitus and diabetic peripheral neuropathy who were given any treatment for diabetic peripheral neuropathy. Risk of bias was assessed using the Delphi list of criteria. Data from the trials were extracted using standardized data extraction sheets by two authors independently. All analyses were performed using RevMan 5.2. In case of clinical homogeneity, statistical pooling was performed using a random effects model. RESULTS: This review included 27 trials on pharmacological, non-pharmacological and alternative treatments. In the meta-analysis of trials of α-lipoic acid versus placebo, total symptom score was reduced by -2.45 (95% CI -4.52; -0.39) with 600 mg i.v. α-lipoic acid (three trials), and was reduced by -1.95 (95% CI -2.89; -1.01) with 600 mg oral α-lipoic acid (two trials). Significant improvements in diabetic peripheral neuropathy symptoms were found with opioids, botulinum toxin A, mexidol, reflexology and Thai foot massage, but not with micronutrients, neurotrophic peptide ORG 2677 and photon stimulation therapy. CONCLUSION: In this review, we found that α-lipoic acid, opioids, botulinum toxin A, mexidol, reflexology and Thai foot massage had significant beneficial results.

Hyperbaric oxygen therapy improves colorectal anastomotic healing.

PURPOSE: Hyperbaric oxygen treatment (HBOT) has been found to improve the healing of poorly oxygenated tissues. This study aimed to investigate the influence of HBOT on the healing in ischemic colorectal anastomosis. METHODS: Forty Wistar rats were randomly divided into a treatment group that received HBOT for 10 consecutive days (7 days before and 3 days after surgery), or in a control group, which did not receive the therapy. Colectomy with an ischemic anastomosis was performed in all rats. In each group, the rats were followed for 3 or 7 days after surgery to determine the influence of HBOT on anastomotic healing. RESULTS: Five rats from each group died during follow-up. No anastomotic dehiscence was seen in the HBOT group, compared to 37.5 % and 28.6 % dehiscence in the control group on postoperative day (POD) 3 and 7, respectively. The HBOT group had a significantly higher bursting pressure (130.9 ± 17.0 mmHg) than the control group (88.4 ± 46.7 mmHg; p = 0.03) on POD 3. On POD 3 and POD 7, the adhesion severity was significantly higher in the control groups than in the HBOT groups (p < 0.005). Kidney function (creatinine level) of the HBOT group was significantly better than of the control group on POD 7 (p = 0.001). Interestingly, a significantly higher number of CD206+ cells (marker for type 2 macrophages) was observed in the HBOT group at the anastomotic area on POD 3. CONCLUSION: Hyperbaric oxygen enhanced the healing of ischemic anastomoses in rats and improved the postoperative kidney function.

Assessment of volumetric changes with a best-fit method in three-dimensional stereophotograms.

OBJECTIVE: Different three-dimensional stereophotogrammetry systems and analyzing methods exist that often use landmarks for comparison. Measurement errors in landmark or surface comparison are mostly within 1 mm, which seems clinically acceptable. The aim of this study was to validate a three-dimensional stereophotogrammetric best-fit method of assessing volumetric changes and to compare three devices. METHODS: The validation of the best-fit method was at first done on a life-size dummy head. Scans were made in the ideal position, as well as in four additional positions, and a scan was made in which a soft putty specimen was added to the dummy head. The comparison was executed with a best-fit method using triangulation. Student's t tests were used to detect statistically significant differences. Second, comparisons were made among scans of a white man in the ideal position and with volume changes added. RESULTS: The different positions tested for the dummy head showed no significant volume differences within each system or among systems. The differences found when adding a soft putty specimen fell into the same range as the differences between various positions. The differences within a live situation were 10 times greater compared with the dummy-head situation. CONCLUSIONS: In a dummy-head situation, the different systems gave similar results when tested with a best-fit method. However, in live situations the differences may become 10 times greater, possibly due to different facial expressions. These differences may become clinically relevant and, therefore, further research in volumetric changes is needed.

Recommendations for optimal distraction protocols for various animal models on the basis of a systematic review of the literature.

The principles of orthopaedic distraction osteogenesis (DO) have been successfully applied to the craniofacial skeleton, but the latency time, rate and rhythm of distraction, and length of the consolidation period that are optimal for long-bone distraction may be suboptimal for craniofacial DO. The aim of this study was to provide recommendations for optimal distraction parameters in animal experimental research on craniofacial DO. The data used were from studies, added to the PubMed database between 1 January 1973 and 1 January 2007, on the outcome of DO resulting from variations in a single distraction parameter while standardizing the other distraction parameters. Although experimental animal group sizes were rather small, especially in those studies that used large animals, and both skeletally mature and immature animals were used, the (in most cases quantitative) data provided useful information on the optimal parameters in craniofacial DO. A latency period may not be necessary at all. Distraction should be performed at a rate of 1mm/day (this may be halved when small animals such as rats are used) preferably with a continuous rhythm, followed by a consolidation period of 6-8 weeks. These recommendations can be used as basic guidelines for further animal experimental studies on craniofacial DO.

Mucosal keratinocyte isolation: a short comparative study on thermolysin and dispase.

New techniques for reconstructing large defects of the floor of the mouth include the use of cultured mucosal substitutes. The purpose of this study was to compare dispase and thermolysin for keratinocyte isolation. Keratinocyte yield per surface area of rabbit buccal mucosa was assessed by histology, cytokeratin 13 (CK13) staining, seeding efficiency analysis and cell diameter quantification. Surface areas of cultured mucosa were calculated. Histology showed that treatment by thermolysin resulted in incomplete separation of epidermis from dermis. Also, the absolute number of keratinocytes/cm(2) isolated mucosa, cell yield, cell size and seeding efficiencies was higher in the dispase group. A 3.45-fold larger graft could be reconstituted using dispase. The use of dispase, rather than thermolysin, to isolate cells from buccal mucosa is concluded to be favourable.

Expression of basic fibroblast growth factor and fibroblast growth factor receptor genes in cultured rat aortic smooth muscle cells.

Basic fibroblast growth factor (bFGF) exerts a differential effect on DNA synthesis, bFGF mRNA synthesis, and expression of FGF-receptor genes by cultured smooth muscle cells from aortae of newborn and adult rats (used as a model in atherosclerosis research). Cells from adult animals, are more sensitive to bFGF, and bFGF triggers its own mRNA synthesis. Moreover, the level of the transcript of the FGFR-1 gene (coding for the most abundant FGF-receptor in smooth muscle cells) is higher in smooth muscle cells from adult rats. In contrast, the FGFR-3 gene only is expressed in smooth muscle cells from newborn rats. Crosslinking of [125I]bFGF to its receptor showed 130 kDa and 160 kDa complexes both in newborn and adult smooth muscle cells.

Serial noninvasive photoacoustic imaging of neovascularization in tumor angiogenesis.

We present photoacoustic images of tumor neovascularization obtained over a 10-day period after subcutaneous inoculation of pancreatic tumor cells in a rat. The images were obtained from ultrasound generated by absorption in hemoglobin of short laser pulses at a wavelength of 1064 nm. The ultrasound signals were measured in reflection mode using a single scanning piezodetector, and images were reconstructed with a weighted delay-and-sum algorithm. Three-dimensional data visualize the development and quantify the extent of individual blood vessels around the growing tumor, blood concentration changes inside the tumor and growth in depth of the neovascularized region.

Human insulin-like growth factor (IGF) binding protein-1 inhibits IGF-I-stimulated body growth but stimulates growth of the kidney in snell dwarf mice.

The actions of insulin-like growth factor-I (IGF-I) are modulated by IGF binding proteins (IGFBPs). The effects of IGFBP-1 in vivo are insufficiently known, with respect to inhibitory or stimulatory actions on IGF-induced growth of specific organs. Therefore, we studied the effects of IGFBP-1 on IGF-I-induced somatic and organ growth in pituitary-deficient Snell dwarf mice. Human GH, IGF-I, IGFBP-1, and a preequilibrated combination of equimolar amounts of IGF-I and IGFBP-1 were administered sc during 4 weeks. Treatment with IGF-I alone induced a significant increase in body length (108% of control) and weight (112%) as well as an increase in weight of the submandibular salivary glands (135%), kidneys (124%), femoral muscles (111%), testes (129%), and spleen (126%) compared with saline-treated controls. IGFBP-1 alone induced a significant increase in weight of the kidneys (152% of control). Coadministration of IGF-I with IGFBP-1 neutralized the stimulating effects of IGF-I on body length and weight as well as on the femoral muscles and testes. In contrast, the weights of the submandibular salivary glands (143%) were not significantly different from those of IGF-I-treated animals, whereas the weights of the kidneys (171%) and spleen (156%) were significantly increased compared with IGF-I-treated mice. The effect of IGFBP-1 plus IGF-I on kidney weight was not significantly greater than the effect of IGFBP-1 alone. Western ligand blotting showed induction of the IGFBP-3 doublet as well as IGFBPs with molecular masses of 24 kDa, most probably IGFBP-4, by human GH, IGF-I alone, and IGF-I in combination with IGFBP-1. Our data show that coadministration of IGFBP-1 inhibits IGF-I-induced body growth of GH-deficient mice but significantly stimulates the growth promoting effects of IGF-I on the kidneys and the spleen. These data warrant further investigation because differences in concentrations of IGFBP-1 occurring in vivo may influence IGF-I-induced anabolic processes.

Generation of antisera to mouse insulin-like growth factor binding proteins (IGFBP)-1 to -6: comparison of IGFBP protein and messenger ribonucleic acid localization in the mouse embryo.

The insulin-like growth factor (IGF) system is an important regulator of fetal growth and differentiation. IGF bioavailability is modulated by IGF binding proteins (IGFBPs). We have generated six different antisera, directed to synthetic peptide fragments of mouse IGFBP-1 through -6. The specificity of the produced antisera was demonstrated by enzyme-linked immunosorbent assay, Western blotting, and by immunohistochemistry on sections of mouse embryos of 13.5 days post coitum. Specificity for the IGFBP-2 through -6 antisera also was confirmed immunohistochemically in liver and lung of corresponding gene deletion (knock-out) mutant mice and wild-type litter mates. Immunohistochemistry and messenger RNA (mRNA) in situ hybridization on sections of mouse embryos of 13.5 days post coitum revealed tissue-specific expression patterns for the six IGFBPs. The only site of IGFBP-1 protein and mRNA production was the liver. IGFBP-2, -4, and -5 protein and mRNA were detected in various organs and tissues. IGFBP-3 and -6 protein and mRNA levels were low. In several tissues, such as lung, liver, kidney, and tongue, more than one IGFBP (protein and mRNA) could be detected. Differences between mRNA and protein localization were extensive for IGFBP-3, -5, and -6, suggesting that these IGFBPs are secreted and transported. These results confirm the different spatial localization of the IGFBPs, on the mRNA and protein level. The overlapping mRNA and protein localization for IGFBP-2 and -4, on the other hand, may indicate that these IGFBPs also function in an auto- or paracrine manner.

Nucleotide sequence of the rat gamma-crystallin gene region and comparison with an orthologous human region.

The sequences of a 51-kb region containing the cluster of five rat gamma-crystallin-coding genes (CRYG) and of a 7-kb region surrounding the sixth rat CRYG gene were determined. Approximately 78% of the total sequence represents intergenic DNA. We also sequenced 22 kb of DNA from the human CRYG gene cluster. All CRYG genes are associated with CpG-rich regions. The sequence similarity between the human and rat gene regions drops sharply (to 65%) in intronic and 3'-flanking regions but decreases only gradually in the 5'-flanking region. Highly conserved regions (greater than 80%) are found as far upstream as 1.5 kb. Overall intergenic distances are conserved. The human region contains much more repetitive DNA (24% vs. 10%) but less simple-sequence (sps) DNA (0.7% vs. 4%) than the rat region. Almost all repeats and spsDNA elements are located in the intergenic region. The location of repetitive and spsDNA differs between the orthologous regions and these elements were probably inserted after the evolutionary separation of rat and man. The Alu repeats in man and the B3 repeats in the rat are close copies of their respective consensus sequences and bordered by virtually perfect repeats. In contrast, the B1 and B2 repeats in the rat have diverged considerably from the consensus sequence and the surrounding direct repeats are usually imperfect. Thus the dispersion of the B1 and B2 repeats in the rat probably preceded that of the B3 repeats. Within the rat genomic region the spacing of Z-DNA elements is surprisingly regular, they are located about 12 kb apart. A search for putative matrix-associated regions suggests that the rat CRYG gene cluster is organized into two chromosomal domains.

Effect of ploidy on transcription levels in cultured rat aortic smooth muscle cells.

Aging and hypertension increase the number of polyploid smooth muscle cells (SMC) in a blood vessel. We assessed the effect of ploidy on the transcription of several genes in SMC cultures derived from newborn and adult rats. In diploid and tetraploid subcultures of SMC from newborn rats, RNA expression of the genes assayed is linked with ploidy. However, when phenotypically different SMC cultures derived from newborn and adult rats were compared, transcription levels varied from gene to gene and not linked with the ploidy. Thus, differences in gene expression due to polyploidy are superimposed on those due to other phenotypical features.

IGF, type I IGF receptor and IGF-binding protein mRNA expression in the developing mouse lung.

The IGFs are important mitogens involved in lung growth and development. The regulation of IGF action depends not only on the expression of IGFs and IGF receptors, but also on the modulation of IGF activity by IGF-binding proteins (IGFBPs). In this study, we describe the mRNA expression of IGF-I, IGF-II, type I IGF receptor, IGFBP-2, IGFBP-4 and IGFBP-5 during mouse lung development as studied by in situ hybridization techniques. The IGF, type I IGF receptor and IGFBP-2, -4 and -5 genes were expressed in developing lung as early as embryonal day 12.5. Expression of IGFBPs-1, -3 and -6 was below detection. IGF and IGFBP-2 mRNAs were expressed both in mesenchymal and epithelial cells. Type I IGF receptor transcripts were also observed throughout the developing lung, with the exception of the epithelial cells of the bronchi after embryonal day 15. Furthermore, mRNA expression of IGFBPs-4 and -5 was noted in neighbouring cell types, and after embryonal day 15, co-expression of the type I IGF receptor and IGFBP-4 transcripts was detected. The observed expression patterns imply that the IGFBP-2, -4 and -5 genes are differentially regulated during embryonic development and suggest that each may have a discrete function. A possible role for IGFBPs-2, -4 and -5 is to participate in the regulation of cell-specific IGF responses during mouse lung development.

IGF, type I IGF receptor and IGF-binding protein mRNA expression in kidney and liver of potassium-depleted and normal rats infused with IGF-I.

Dietary potassium (K) depletion is known to reduce body weight gain and organ growth, except for kidney which increases in weight. This renal hypertrophy is preceded by increased renal IGF-I levels. In the present study, we investigated IGF-I and -II, type I IGF receptor and IGF-binding protein (IGFBP) mRNA expression in liver and kidney of K-depleted and normal rats infused with vehicle or recombinant human IGF-I. Body weight gain was almost completely arrested in K-depleted rats without any stimulatory effect of IGF-I infusion. Both absolute and relative kidney weight (kidney weight/body weight) were significantly increased in K-depleted rats and this was further enhanced by IGF-I infusion. In contrast, relative liver weight was comparable in the different groups and unaffected by IGF-I infusion. IGF-I mRNA expression was significantly lower in kidney and liver of K-depleted animals whereas type I IGF receptor levels were unchanged. In contrast, in kidney, K depletion increased IGFBP-1 and -2 mRNA expression with no additional effect of IGF-I infusion. In liver of K-depleted animals, IGFBP-1 mRNA expression was increased whereas increased IGFBP-1 and -2 mRNA expression was observed when these animals were infused with IGF-I. These observations may point towards a differential mode of action of the IGFBPs. In kidney increased IGFBP-1 and -2 mRNA expression may enhance IGF-I bioavailability with subsequent kidney growth. In liver, with clearly detectable type I IGF receptor mRNA expression, increased IGFBP levels may protect from IGF-I-induced organ growth by decreasing IGF-I bioavailability.

Stimulation of hepatic insulin-like growth factor-binding protein-1 and -3 gene expression by octreotide in rats.

It has recently been demonstrated in various clinical experiments that native somatostatin and its long-acting analogues increase circulating levels of insulin-like growth factor-binding protein-1 (IGFBP-1) within 1-2 h, independent of effects on circulating insulin or glucose levels. Using human hepatoma cells in vitro the somatostatin analogue, octreotide, has been shown to increase IGFBP-1 mRNA within 24 h indicative of a direct stimulatory effect of octreotide on IGFBP-1 synthesis. In order to ascertain whether octreotide acutely stimulates IGFBP-1 mRNA in vivo, placebo or two doses of octreotide were injected subcutaneously into three groups of rats. One hour after saline or octreotide administration, liver, kidney and serum were obtained for the measurement of IGFBPs-1 to -6 mRNA in tissue and IGFBPs and IGF-I in serum. Octreotide increased liver IGFBP-1 (562%) and IGFBP-3 (23%) mRNA expression with a concomitant rise in the circulating 30 kDa (106%) and 38-42 kDa (23%) IGFBPs. No detectable changes were seen in other liver IGFBP transcripts, other circulating IGFBPs or in any of the kidney IGFBP transcripts. Serum IGF-I increased by 37% in the animals receiving the high octreotide dose. No concomitant changes were observed in glucose or insulin levels. These data show that octreotide acutely stimulates hepatic IGFBP-1 and -3 mRNA in vivo in rats. The stimulating effect on IGFBP-3 presents a possible hitherto unknown form of regulation of IGFBP-3 whilst the effect on IGFBP-1 indicates that the stimulatory effect of octreotide on circulating IGFBP-1 described in clinical trials may be due to increased hepatic production. The present findings may be of importance in the clinical use of octreotide.

Dose-response effects of a new growth hormone receptor antagonist (B2036-PEG) on circulating, hepatic and renal expression of the growth hormone/insulin-like growth factor system in adult mice.

The effects of growth hormone (GH) in regulating the expression of the hepatic and renal GH and insulin-like growth factor (IGF) system were studied by administering a novel GH receptor antagonist (GHRA) (B2036-PEG) at different doses (0, 1.25, 2.5, 5 and 10 mg/kg/day) to mice for 7 days. No differences were observed in the groups with respect to body weight, food consumption or blood glucose. However, a dose-dependent decrease was observed in circulating IGF-I levels and in hepatic and renal IGF-I levels at the highest doses. In contrast, in the 5 and 10 mg/kg/day GHRA groups, circulating and hepatic transcriptional IGF binding protein-3 (IGFBP-3) levels were not modified, likely resulting in a significantly decreased IGF-I/IGFBP-3 ratio. Hepatic GH receptor (GHR) and GH binding protein (GHBP) mRNA levels increased significantly in all GHRA dosage groups. Endogenous circulatory GH levels increased significantly in the 2.5 and 5 mg/kg/day GHRA groups. Remarkably, increased circulating IGFBP-4 and hepatic IGFBP-4 mRNA levels were observed in all GHRA administration groups. Renal GHR and GHBP mRNA levels were not modified by GHRA administration at the highest doses. Also, renal IGFBP-3 mRNA levels remained unchanged in most GHRA administration groups, whereas IGFBP-1, -4 and -5 mRNA levels were significantly increased in the 5 and 10 mg/kg/day GHRA administration groups. In conclusion, the effects of a specific GHR blockade on circulating, hepatic and renal GH/IGF axis reported here, may prove useful in the future clinical use of GHRAs.

The effect of epidermal growth factor and IGF-I infusion on hepatic and renal expression of the IGF-system in adult female rats.

Systemic administration of epidermal growth factor (EGF) in neonatal rats results in reduced body weight gain and decreased circulating levels of IGF-I, suggesting its involvement in EGF-induced growth retardation. We investigated the effect of EGF and/or IGF-I administration for 7 days on circulating IGF-I and IGFBP levels and hepatic and renal IGF-system mRNA expression profiles in adult female rats. EGF administration (30 microg/rat/day) did not influence body weight, liver or kidney weight. In contrast, IGF-I (400 microg/rat/day) and EGF/IGF-I administration increased both body weight and kidney weight. Also, serum IGF-I and the 30 kDa IGFBPs (IGFBP-1 and -2) were significantly increased in these groups. Serum IGFBP-3 levels increased in the IGF-I group along with increased hepatic IGFBP-1 and -3 mRNA levels. In contrast, in the EGF administration group serum IGFBP-3 levels were significantly decreased; however, the mRNA levels remained unchanged. In the EGF/IGF-I administration group, serum IGF-I and IGFBP-3 levels were significantly lowered when compared with the IGF-I administration group. This was in contrast to the effect on kidney weight increase that was identical for the IGF-I and EGF/IGF-I groups. The decrease in serum IGFBP-3 was not reflected at the hepatic IGFBP-3 mRNA level. IGFBP-3 expression might be regulated at a post-transcriptional level although EGF induced IGFBP-3 proteolysis could not be demonstrated in vitro. We conclude that EGF administration reduced serum IGFBP-3 whereas IGF-I administration increased the level of IGFBP-3 and IGF-I and resulted in an increased body and kidney weight in adult female rats.

The role of the IGF axis in IGFBP-1 and IGF-I induced renal enlargement in Snell dwarf mice.

Insulin-like growth factor (IGF) binding protein-1 (IGFBP-1) is generally believed to inhibit IGF action in the circulation. In contrast, IGFBP-1 has been reported to interact with cell surfaces and enhance IGF-I action locally in some tissues. Renal IGFBP-1 levels are found elevated in various conditions characterized by renal growth (e.g. diabetes mellitus, hypokalemia). To test whether IGFBP-1 is a renotropic factor, IGFBP-1 was administered alone or in combination with IGF-I to Snell dwarf mice, an in vivo model without compensatory feedback effects on growth hormone (GH) secretion. In three control groups of Snell dwarf mice, placebo, GH or IGF-I was administered. Compared with placebo, kidney weight increased in all treated groups, however, with different effects on kidney morphology. Administration of IGF-I, alone or in combination with IGFBP-1, tended to increase glomerular volume, while no changes were seen in the other groups. Administration of IGFBP-1 or IGFBP-1+IGF-I both caused dilatation of the thin limbs of Henle's loop, while GH or IGF-I administration had no visible effect. Furthermore, IGF-I administration resulted in an increased mean number of nuclei per cortical area and renal weight, whereas GH, IGF-I+IGFBP-1 or IGFBP-1 caused a decreased renal nuclei number. In situ hybridization and immunohistochemistry showed specific changes of the renal IGF system expression patterns in the different groups. Particularly, IGFBP-1 administration resulted in extensive changes in the mRNA expression of the renal IGF system, whereas the other administration regimen resulted in less prominent modifications. In contrast, administration of IGFBP-1 and IGFBP-1+IGF-I resulted in identical changes in the protein expression of the renal IGF system. Our results indicate that IGFBP-1, alone or in combination with IGF-I, demonstrated effects on the renal tubular system that differ from the effects of IGF-I.

cDNA cloning and mRNA expression of the six mouse insulin-like growth factor binding proteins.

The insulin-like growth factor binding proteins (IGFBPs) comprise a family of six distinct proteins which modulate insulin-like growth factor action. We have isolated cDNAs encoding the six mouse IGFBPs (mIGFBPs). In addition, we studied the mRNA expression of the six mIGFBPs during development and in various adult tissues. Our results show that each of the six mIGFBPs is highly homologous to their human and rat counterparts, whereas only the N and C terminal ends are conserved between the six mIGFBPs. Northern blotting revealed that mIGFBP-2, -3, -4 and -5 genes are already expressed at gestational day 11.5, suggesting a role for these mIGFBPs in embryonal development. In liver, a peak of mIGFBP-1 mRNA expression was found around birth, suggesting a function for mIGFBP-1 in the newborn mouse. Finally, tissue-specific expression of the six mouse IGFBP genes was observed in adult tissues suggesting different roles or modes of actions in adult life.

Proliferation of the murine corticotropic tumour cell line AtT20 is affected by hypophysiotrophic hormones, growth factors and glucocorticoids.

In pituitary-dependent hyperadrenocorticism (Cushing's disease), the disturbed regulation of ACTH secretion is associated with neoplastic transformation of corticotropic cells. As these two phenomena are almost indissolubly connected, it is of prime importance to elucidate the factor(s) that induce corticotropic cell proliferation. Here we report on the effects of hypophysiotrophic hormones and intrapituitary growth factors on the proliferation and hormone secretion of the murine corticotropic tumour cell line AtT20/D16v, as measured by DNA content, and ACTH concentration in culture media. In addition, sensitivity to the inhibitory effect of cortisol was assessed under various conditions. Corticotropin releasing hormone (CRH) and vasopressin (AVP) induced proliferation of AtT20-cells. In contrast to that caused by AVP, the CRH-induced proliferation was associated with increased ACTH secretion, which could be inhibited by cortisol. Insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) also stimulated the proliferation of AtT20-cells. The proliferation of AtT20-cells was significantly inhibited by cortisol in all tests. The IGF-I-induced proliferation was the least sensitive to inhibition by cortisol. The growth factors did not stimulate ACTH secretion but IGF-I differed in that it prevented the inhibition of basal ACTH secretion by cortisol. Additional experiments (Western ligand blot analysis) concerning the relative insensitivity of IGF-I induced proliferation to inhibition by cortisol revealed that IGF-I increased the concentration of a 29 kDa IGF binding protein (IGFBP) in the culture medium. The concentration of the 29 kDa IGFBP was slightly decreased by cortisol.(ABSTRACT TRUNCATED AT 250 WORDS)