Thermal requirements for growth, survival and aerobic performance of weatherfish larvae Misgurnus fossilis.

Thermal requirements of larval weatherfish Misgurnus fossilis were investigated in terms of growth, survival and aerobic performance. Growth and survival of M. fossilis larvae acclimated to five temperatures (11, 15, 19, 23 and 27° C) were measured over 25 days. In the upper temperature treatments (19, 23 and 27° C), survival of larvae was stable throughout the entire rearing period (>75%), whereas 11 and 15° C resulted in severe declines in survival (to <10%). Growth of larvae (expressed as dry mass and total length) was highest at 19 and 23° C, but significantly decreased at 27° C. Routine metabolic rate of 3 days post-hatch larvae was estimated as oxygen consumption rate (MO2 ) during acute exposure (30 min to 1 h) to seven temperatures (11, 15, 19, 23, 27, 31 and 35° C). Larval oxygen uptake increased with each consecutive temperature step from 11 to 27° C, until a plateau was reached at temperatures >27° C. All larvae of the 35° C regime, however, died within the MO2 measurement period. M. fossilis larvae show greater than expected tolerance of high temperatures. On the other hand, low temperatures that are within the range of likely habitat conditions are critical because they might lead to high mortality rates when larvae are exposed over periods >10 days. These findings help to improve rearing conditions and to identify suitable waters for stocking and thus support the management of re-introduction activities for endangered M. fossilis.

Exploring the impacts of two separate mixtures of pesticide and surfactants on estrogenic activity in male fathead minnows and rainbow trout.

In this study, male fathead minnows (FHM) (Pimephales promelas) and juvenile rainbow trout (RT; Oncorhynchus mykiss) were exposed to two different surfactant mixtures of analytical-grade nonlyphenol, 4-tert octyphenol, octylphenol ethoxylates, nonylphenol ethoxylates, and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). After a 7-days exposure to environmentally relevant concentrations of these compounds, there was no difference in the relative mRNA expression of vitellogenin (VTG) in male juvenile RT exposed to individual compounds or the 2,4-D-surfactant mixture compared with the control. In male FHM, there was a significant increase in VTG mRNA expression in the high individual treatments of 2,4-D and the surfactants but not the 2,4-D-surfactant mixtures compared with the control. These results were compared with another study exposing male FHM to individual and a mixture of alkylphenols and alkylphenol ethoxylates in two different combinations with the herbicide diuron and the insecticide bifenthrin. There were no differences in the relative expression of VTG mRNA amongst individual exposures and the control. Interestingly, when the ethoxylate mixture was combined with diuron, there was a significant decrease in the relative mRNA expression of VTG compared with the control. However, when the ethoxylate mixture was combined with both diuron and bifenthrin, there was a significant increase in the relative mRNA expression of VTG in male compared with all other groups in the multichemical mixture. The results of this study highlight differences between species and measurements of VTG in assessing the risk of mixtures to aquatic organisms.

Rapid artefact removal and H&E-stained tissue segmentation.

We present an innovative method for rapidly segmenting haematoxylin and eosin (H&E)-stained tissue in whole-slide images (WSIs) that eliminates a wide range of undesirable artefacts such as pen marks and scanning artefacts. Our method involves taking a single-channel representation of a low-magnification RGB overview of the WSI in which the pixel values are bimodally distributed such that H&E-stained tissue is easily distinguished from both background and a wide variety of artefacts. We demonstrate our method on 30 WSIs prepared from a wide range of institutions and WSI digital scanners, each containing substantial artefacts, and compare it to segmentations provided by Otsu thresholding and Histolab tissue segmentation and pen filtering tools. We found that our method segmented the tissue and fully removed all artefacts in 29 out of 30 WSIs, whereas Otsu thresholding failed to remove any artefacts, and the Histolab pen filtering tools only partially removed the pen marks. The beauty of our approach lies in its simplicity: manipulating RGB colour space and using Otsu thresholding allows for the segmentation of H&E-stained tissue and the rapid removal of artefacts without the need for machine learning or parameter tuning.

Stain normalization gives greater generalizability than stain jittering in neural network training for the classification of coeliac disease in duodenal biopsy whole slide images.

Around 1% of the population of the UK and North America have a diagnosis of coeliac disease (CD), due to a damaging immune response to the small intestine. Assessing whether a patient has CD relies primarily on the examination of a duodenal biopsy, an unavoidably subjective process with poor inter-observer concordance. Wei et al. [11] developed a neural network-based method for diagnosing CD using a dataset of duodenal biopsy whole slide images (WSIs). As all training and validation data came from one source, there was no guarantee that their results would generalize to WSIs obtained from different scanners and laboratories. In this study, the effects of applying stain normalization and jittering to the training data were compared. We trained a deep neural network on 331 WSIs obtained with a Ventana scanner (WSIs; CD: n=190; normal: n=141) to classify presence of CD. In order to test the effects of stain processing when validating on WSIs scanned on varying scanners and from varying laboratories, the neural network was validated on 4 datasets: WSIs of slides scanned on a Ventana scanner (WSIs; CD: n=48; normal: n=35), WSIs of the same slides rescanned on a Hamamatsu scanner (WSIs; CD: n=48; normal: n=35), WSIs of the same slides rescanned on an Aperio scanner (WSIs; CD: n=48; normal: n=35), and WSIs of different slides scanned on an Aperio scanner (WSIs; CD: n=38; normal: n=37). Without stain processing, the F1 scores of the neural network were 0.947, 0.619, 0.746, and 0.727 when validating on the Ventana validation WSIs, Hamamatsu and Aperio rescans of the Ventana validation WSIs, and Aperio WSIs from a different source respectively. With stain normalization, the performance of the neural network improved significantly with respective F1 scores 0.982, 0.943, 0.903, and 0.847. Stain jittering resulted in a better performance than stain normalization when validating on data from the same source F1 score 1.000, but resulted in poorer performance than stain normalization when validating on WSIs from different scanners (F1 scores 0.939, 0.814, and 0.747). This study shows the importance of stain processing, in particular stain normalization, when training machine learning models on duodenal biopsy WSIs to ensure generalizability between different scanners and laboratories.

Multiple-instance-learning-based detection of coeliac disease in histological whole-slide images.

We present a multiple-instance-learning-based scheme for detecting coeliac disease, an autoimmune disorder affecting the intestine, in histological whole-slide images (WSIs) of duodenal biopsies. We train our model to detect 2 distinct classes, normal tissue and coeliac disease, on the patch-level, and in turn leverage slide-level classifications. Using 5-fold cross-validation in a training set of 1841 (1163 normal; 680 coeliac disease) WSIs, our model classifies slides as normal with accuracy (96.7±0.6)%, precision (98.0±1.7)%, and recall (96.8±2.5)%, and as coeliac disease with accuracy (96.7±0.5)%, precision (94.9±3.7)%, and recall (96.5±2.9)% where the error bars are the cross-validation standard deviation. We apply our model to 2 test sets: one containing 191 WSIs (126 normal; 65 coeliac) from the same sources as the training data, and another from a completely independent source, containing 34 WSIs (17 normal; 17 coeliac), obtained with a scanner model not represented in the training data. Using the same-source test data, our model classifies slides as normal with accuracy 96.5%, precision 98.4% and recall 96.1%, and positive for coeliac disease with accuracy 96.5%, precision 93.5%, and recall 97.3%. Using the different-source test data the model classifies slides as normal with accuracy 94.1% (32/34), precision 89.5%, and recall 100%, and as positive for coeliac disease with accuracy 94.1%, precision 100%, and recall 88.2%. We discuss generalising our approach to screen for a range of pathologies.

A 3' UTR transition within DEFB1 is associated with chronic and aggressive periodontitis.

Periodontal diseases are complex inflammatory diseases and affect up to 20% of the worldwide population. An unbalanced reaction of the immune system toward microbial pathogens is considered as the key factor in the development of periodontitis. Defensins have a strong antimicrobial function and are important contributors of the immune system toward maintaining health. Here, we present the first systematic association study of DEFB1. Using a haplotype-tagging single nucleotide polymorphism (SNP) approach, including described promoter SNPs of DEFB1, we investigated the associations of the selected variants in a large population (N=1337 cases and 2887 ethnically matched controls). The 3' untranslated region SNP, rs1047031, showed the most significant association signal for homozygous carriers of the rare A allele (P=0.002) with an increased genetic risk of 1.3 (95% confidence interval: 1.11-1.57). The association was consistent with the specific periodontitis forms: chronic periodontitis (odds ratio=2.2 (95% confidence interval: 1.16-4.35), P=0.02), and aggressive periodontitis (odds ratio=1.3 (95% confidence interval 1.04-1.68), P=0.02). Sequencing of regulatory and exonic regions of DEFB1 identified no other associated variant, pointing toward rs1047031 as likely being the causative variant. Prediction of microRNA targets identified a potential microRNA-binding site at the position of rs1047031.

Safety and feasibility audit of a home-based drug-transitioning approach for patients with pulmonary arterial hypertension: an observational study.

BACKGROUND: Newer endothelin receptor antagonists (ERAs) used to treat patients with pulmonary arterial hypertension (PAH) are associated with fewer drug-drug interactions than bosentan and require less monitoring. This, combined with a pharmacokinetic basis for improved efficacy, means there may be a clinical rationale for changing therapies. However, this can be challenging and few data on its safety in patients with PAH are available. AIMS: At the Royal Free Hospital in London, UK, home-based medication transitioning has been standard practice since 2009 to avoid unnecessary hospital visits for patients, unless there is a clinical imperative. In this audit of standard practice we evaluated the consequences of adopting such a strategy when transitioning PAH patients between ERA therapies. METHODS AND RESULTS: Using a Clinical Nurse Specialist-led, home-based transitioning strategy, 92 patients with PAH were transitioned from bosentan to macitentan or ambrisentan. Observational data were analysed retrospectively. The majority of patients were female with PAH associated with connective tissue disease and their ERA was changed in the hope of improving efficacy. The process was well tolerated with no adverse events associated with the process. Seventeen patients died during the study (macitentan, n = 5; ambrisentan, n = 12). None of the deaths was considered related to ERA treatment. The majority of patients remained clinically stable, based on WHO functional class and exercise capacity. CONCLUSION: An established home-based transitioning strategy can be adopted safely for patients with PAH changing ERA therapies. Most patients remained stable and the therapy change was well tolerated.

Protection of mice against 7,12-dimethylbenz(a)anthracene-induced skin tumors by immunization with a fluorinated analog of the carcinogen.

5-Fluoro-12-methylbenzanthryl-7-acetic acid (5-FMBAAA) is an analog of the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) with little or no carcinogenic activity. CD-1 mice immunized with 5-FMBAAA conjugated to bovine serum albumin (BSA) developed serum antibodies capable of binding DMBA. As a means of testing whether this immunization protected against DMBA-induced tumors, a low-dose carcinogenesis model system was developed, entailing the repeated skin application of 25 ng DMBA in dodecane alternating with applications of the tumor promoter, phorbol myristate acetate. Mice immunized with the 5-FMBAAA:BSA conjugate and subsequently exposed to this low-dose regimen for 40 weeks developed significantly fewer skin tumors (0.23 papilloma/mouse) than did unimmunized mice, mice immunized with BSA, or mice immunized with an unconjugated mixture of BSA and 5-FMBAAA (0.47 to 0.54 papilloma/mouse). Immunization did not reduce tumor incidence in mice treated with phorbol myristate acetate alone. The results suggest that, when mice are exposed to a carcinogen at doses low enough to approach environmental levels, immunization against the carcinogen can provide specific protection.

Reliability of 24-h void frequency as an index of hydration status when euhydrated and hypohydrated.

BACKGROUND/OBJECTIVES: Void frequency (VF) is significantly correlated to hydration status, but it is unknown whether VF is reliable when an individual is repeatedly euhydrated (EU) or hypohydrated (HY). The purpose of this study was to test the reliability of VF when individuals were EU or HY on multiple occasions. SUBJECTS/METHODS: Fourteen males (age 22±2 years, mass 79.1±12.8 kg) completed three EU trials achieved with 24-h ad libitum fluid intake, and 14 males (age 22±2 years, mass 78.6±10.4 kg) completed three HY trials achieved with 24-h fluid restriction. Twenty-four hour urine was collected and analyzed for specific gravity (USG) and VF. Subjects voided at a 'normal urgency' (rated a '2' on a 0-4 perceptual scale) throughout each 24-h period. RESULTS: Twenty-four hour USG was greater and VF was lower when HY (1.026±0.003 and 5±2, respectively) versus EU (1.014±0.003 and 7±2; both P<0.05). Intra-class correlations for VF between the three trials at each hydration status were deemed acceptable (0.863 and 0.849 for EU and HY, respectively). Within-subject coefficients of variation for VF were 15±9 and 21±14% for the EU and HY trials. CONCLUSIONS: VF is a reliable index of 24-h hydration status when healthy young males are EU or HY and voiding at a consistent 'urgency'.

Role of macrophage-expressed adipocyte fatty acid binding protein in the development of accelerated atherosclerosis in hypercholesterolemic mice.

Atherosclerosis is an inflammatory disease process associated with elevated levels of plasma cholesterol, especially low-density lipoproteins. The latter become trapped within the arterial wall and are oxidized and taken up by macrophages to form foam cells. This process is an initiating event for atherosclerosis. Fatty acid binding proteins (FABP) are involved in fatty acid metabolism and cellular lipid transport, and adipocyte FABP (aP2) is also expressed in macrophages. We recently generated mice lacking both apolipoprotein (Apo)E and aP2 (ApoE-/-aP2-/-) and found that these mice, compared with ApoE-/- mice, developed markedly smaller atherosclerotic lesions that contained fewer macrophages. Here we investigated the mechanism(s) responsible for this prevention of atherosclerotic lesion formation. Bone marrow transplantations were performed in ApoE-/- mice, receiving cells from either ApoE-/- or ApoE-/-aP2-/- mice. The lack of aP2 in donor marrow cells led to the development of smaller (5.5-fold) atherosclerotic lesions in the recipient mice. No differences were found in plasma cholesterol, glucose, or insulin levels between recipients of bone marrow cells from ApoE-/- or ApoE-/-aP2-/- mice. However, the expression of chemoattractant and inflammatory cytokines was decreased in macrophages from ApoE-/-aP2-/- mice compared with ApoE-/- mice, which may contribute to the decrease in atherosclerotic lesion formation. Taken together, we demonstrate the importance of macrophage aP2 in the development of atherosclerotic lesions.

Osteoclast recruitment in response to human bone matrix is age related.

The effect of bone matrix age on the recruitment and differentiation of osteoclast precursors was studied using the chick chorioallantoic membrane (CAM) implant system. Devitalized mineralized bone particles (75-250 microns) were prepared from human femoral cortical bone obtained postmortem from 8 men (age range: 18-72 years). The particles were implanted onto the CAM and 8 days later implants were harvested and processed for light microscopic, morphometric or immunohistochemical analysis. Histomorphometric analysis was performed on samples representing each donor age. The analysis was grouped into three categories consisting of bone from young adults (18-20 years), adults (34-53 years) and aged individuals (67 years and older). Total osteoclast number, osteoclast number per bone particle, cell area, cell size, number of nuclei per cell profile, nucleocytoplasmic ratio, and the presence of a distinctive osteoclast antigen defined by monoclonal anti-body 121F were determined. Bone matrix from older individuals, and therefore the oldest age group (67 years and older), elicited significantly fewer multinucleated cells when compared to bone matrix from younger donors. The number of nuclei per cell profile was highest in the adult population (34-53 years), and there was a continuous increase in cell area with aging. As a consequence, the nucleocytoplasmic ratio decreased from the youngest to the oldest age group. These findings indicate that, relative to factors that affect the recruitment and differentiation of osteoclast precursor cells, bone matrix of older individuals is changed in quality and/or quantity compared to bone matrix from younger individuals. It is hypothesized that this decline in osteoclast formation in response to older bone matrix may contribute to the impaired bone remodeling associated with aging.

beta-VLDL-induced alterations in growth potentiating activity produced by mononuclear phagocytes.

This report describes the enhancement of growth potentiating activity produced by mononuclear phagocytes that were incubated with beta-migrating very low density lipoproteins (beta-VLDL). Conditioned media harvested from cultured human peripheral blood monocytes incubated in the presence or absence of the lipoprotein were evaluated for their ability to stimulate DNA synthesis ([3H]thymidine incorporation) of sparsely seeded quiescent BHK-21 (BHK) cells as well as neonatal rat aortic smooth muscle cells (NRSMC). Conditioned media from monocytes incubated in the presence of beta-VLDL enhanced [3H]thymidine incorporation into DNA of both BHK and NRSMC, when compared to conditioned media harvested from monocytes incubated in the absence of beta-VLDL. Studying NRSMC, this effect was evident using media collected from monocytes incubated with lipoprotein for 2 days; however, a longer incubation of monocytes plus lipoprotein was necessary to induce changes in growth potentiating activity for BHK cells. Likewise, the effect of beta-VLDL treatment of thioglycollate broth elicited BALB/c mouse peritoneal macrophages was evaluated. Conditioned media from lipoprotein-treated macrophages exhibited greater growth-stimulating activity for both BHK cells and NRSMC when compared to conditioned media from macrophages incubated in the absence of the lipoprotein. beta-VLDL did not affect viability of the mononuclear cells. These findings further implicate the involvement of the monocyte-derived foam cell in the development of atherosclerosis.

Long-term treatment of neonatal aortic smooth muscle cells with beta VLDL induces cholesterol accumulation.

A model for smooth muscle derived foam cells was developed by treating smooth muscle cells isolated from the aortae of neonatal rabbits with beta VLDL for up to 1 month. Hyperlipidemic beta VLDL isolated from cholesterol fed rabbits induced proliferation of the cells that were maintained in lipid deficient serum. In addition, the lipoprotein fraction stimulated [14C]oleic acid incorporation into [14C]cholesteryl ester, even in cultures that had been chronically exposed to the lipoprotein. The accumulation of cholesterol was evaluated and small amounts of cholesteryl ester were demonstrated in cultures treated for 3 days with beta VLDL. However, continued exposure to the lipoprotein resulted in larger elevations in total cholesterol, approximately 65% of which was in the esterified form in cultures treated with 100 micrograms beta VLDL/ml for 24 days. When cholesterol levels were examined as a function of time, it was determined that both total cholesterol and cholesteryl ester levels increased. Approximately 2-3 weeks after lipoprotein was introduced to the culture, maximum levels were attained. Triglyceride levels were also measured and found to increase more than two-fold in cultures that had been incubated in the presence of beta VLDL for 24 days, when compared to cultures incubated in its absence. Examination of the cultures by electron microscopy revealed intracytoplasmic lipid droplets in beta VLDL treated cells. These results suggest that beta VLDL treatment of neonatal aortic smooth muscle cells provides an ideal model in which to study the lipid laden smooth muscle cells that characterize the atherosclerotic plaque.

Formation of adherent monolayers of murine lymphocytes in vitro: the use of serum-free medium and concanavalin A-coated surfaces to promote adherence.

Murine thymus and spleen cells formed adherent monolayers in polystyrene tissue culture flasks when plated in serum-free medium. In the presence of 2% serum, thymus cells adhered poorly, but adherence was greatly enhanced if the flasks had been coated noncovalently with the lectin, concanavalin A. Adherence of leukemic lymphocytes (L1210) required both serum-free medium and concanavalin A-coated flasks; the extent of attachment was proportional to the concentration of the lectin used to coat the flasks at concentrations up to 0.1 mg/ml. Once L1210 cells had attached, they could not be removed by exposure to serum, ethylenediamine tetraacetic acid, trypsin, or alpha-methyl mannoside. Adherent L1210 cells remained capable of metabolism and proliferation during intervals of up to 7 days. The use of adherent monolayers for cytotoxicity assays was demonstrated by an assay for Pseudomonas aeruginosa toxin in EL4 murine leukemia cells.

Retinal Muller glia secrete apolipoproteins E and J which are efficiently assembled into lipoprotein particles.

We have shown that apolipoprotein E (ApoE) is synthesized by Muller cells, the major glial cell of the rabbit retina, and secreted into the vitreous after which it is taken up by retinal ganglion cells and rapidly transported into the optic nerve [Amaratunga et al., J. Biol. Chem. 271 (1996) 5628-5632]. In this report we demonstrate that the ApoE secreted by Muller cells in vivo and in culture is efficiently assembled into lipoprotein particles. Apolipoprotein J (ApoJ) is also synthesized by these cells and assembled into lipoprotein particles. The lipoproteins are triglyceride-rich and contain cholesterol esters and free cholesterol. They are heterogeneous, with densities between 1.006 and 1.18 and diameters between 14 and 45 nm. We discuss the possible role of these lipoproteins in supplying the needs of neurons for lipids, especially long axonal projection neurons such as retinal ganglion cells, which are vulnerable to age-related neurodegenerative diseases including Alzheimer's disease.

Serum amyloid A in Alzheimer's disease brain is predominantly localized to myelin sheaths and axonal membrane.

Immunohistochemical localization of the injury specific apolipoprotein, acute phase serum amyloid A (A-apoSAA), was compared in brains of patients with neuropathologically confirmed Alzheimer's disease (AD), multiple sclerosis (MS), Parkinson's disease (PD); Pick's disease (Pick's), dementia with Lewy bodies (DLB), coronary artery disease (CAD), and schizophrenia. Affected regions of both AD and MS brains showed intense staining for A-apoSAA in comparison to an unaffected region and non-AD/MS brains. The major site of A-apoSAA staining in both diseases was the myelin sheaths of axons in layers V and VI of affected cortex. A-apoSAA contains a cholesterol binding site near its amino terminus and is likely to have a high affinity for cholesterol-rich myelin. These findings, along with our recent evidence that A-apoSAA can inhibit lipid synthesis in vascular smooth muscle cells suggest that A-apoSAA plays a role in the neuronal loss and white matter damage occurring in AD and MS.

Proteolytic activity of Candida albicans and other yeasts.

Clinical isolates of C. albicans (75 strains) and other yeasts (20 strains) were evaluated for their ability to produce a carboxyl acid proteinase in an effort to assess its potential role as a virulence factor. Yeasts were categorized as to the infectious process present in the patient: (1) isolates from patients with invasive disease, (2) isolates from patients with possible invasive disease, (3) isolates from superficially infected patients and (4) isolates from noninfected, colonized patients. Yeasts were grown for 7 days in medium containing bovine serum albumin (BSA) as the sole nitrogen source. The amount of extracellular proteinase was measured at pH 3.2, using BSA as substrate. The majority (97%) of C. albicans isolates produced a detectable proteinase. Some non-C. albicans isolates produced proteinase; however, the amount of activity was generally less than for C. albicans. No correlation was found between the amount of proteolytic activity and the degree of invasiveness of the strains.

Monte Carlo simulations of the imaging performance of metal plate/phosphor screens used in radiotherapy.

The imaging performance of metal plate/phosphor screens which are used for the creation of portal images in radiotherapy is investigated by using Monte Carlo simulations. To this end the modulation transfer function, the noise power spectrum and the detective quantum efficiency [DQE(f)] are calculated for different metals and phosphors and different thicknesses of metal and phosphor for a range of spatial resolutions. The interaction of x-rays with the metal plate/phosphor screen is modeled with the EGS4 electron gamma shower code. Optical transport in the phosphor is modeled by simulating scattering and reabsorption events of individual optical photons. It is shown that metals with a high atomic number perform better than lighter metals in maximizing the DQE(f). It is furthermore shown that the DQE(f) for the metal plate/phosphor screen alone is nearly x-ray quantum absorption limited up to spatial frequencies of 0.4 cycles/mm. In addition, it is argued that the secondary quantum sink of optical photons imposed by the optical chain (mirror, lenses and video camera) leads to a significant degradation of the signal-to-noise ratio at spatial frequencies which are most important for successful registration of portal images. Therefore, the conclusion is that a replacement of the optical chain by a flat array of photodiodes placed directly under the phosphor will lead to a substantial improvement in image quality of portal images.

Insulin-like growth factor-1 stimulates production of mesangial cell matrix components.

Diabetic nephropathy is characterized by mesangial cell proliferation and expansion of the mesangial matrix. Insulin-like growth factor-1 (IGF-1) increases in the kidney early in experimental diabetes. The effect of IGF-1 on mesangial cell proliferation and synthesis of extracellular matrix (ECM) proteins was examined to test the hypothesis that IGF-1 stimulates mesangial cells to synthesize ECM proteins. ECM proteins were measured by immunoprecipitation after metabolic labeling of rat mesangial cells in culture. IGF-1 caused a 2.4-fold increase in mesangial cell proliferation as measured by 3H-thymidine incorporation. IGF-1 caused an increase in cellular laminin, fibronectin and type IV collagen, 46.8 +/- 15.4%, 31.3 +/- 11.4%, and 27.7 +/- 12.6% increase respectively compared to control cells. IGF-1 did not effect cellular type 1 collagen, decrease of 8.2 +/- 8.7%. There was a trend toward increased total protein synthesis by IGF-1, 36.5 +/- 2.5%. In summary, IGF-1 stimulates ECM component production by mesangial cells. Thus, IGF-1 has the capacity to mediate the histologic changes characteristic of diabetic nephropathy.