Cell surface heparan sulfate proteoglycans control the response of renal interstitial fibroblasts to fibroblast growth factor-2

BACKGROUND

While the progression of renal disease to end stage is strongly correlated with tubulointerstitial changes, the control of the fibrotic process within the interstitium is poorly understood. Basic fibroblast growth factor (FGF-2) has been implicated as a major growth factor involved in fibroblast activation and extracellular matrix synthesis. Furthermore, in many cells, the activity of FGF-2 is controlled by a low-affinity but high-capacity interaction with heparan sulfate (HS) proteoglycans (PGs), such as members of the syndecan family. These molecules are likely to be central to the control of interstitial fibrosis, but as yet, there has been no characterization of their synthesis by interstitial cells.

METHODS

The expression of HSPG on the surface of NRK 49F fibroblasts was demonstrated by immunohistochemistry and by metabolic labeling with [(35)S]-sulfate. HSs were characterized by specific enzymatic digestion, size exclusion chromatography, and anion exchange chromatography. The mRNA for syndecan 1 through syndecan 4 in the fibroblasts was detected by semiquantitative reverse transcription-polymerase chain reaction. Fibroblast proliferation was measured by the MTT assay.

RESULTS

Immunohistochemistry and [(35)S]-sulfate-labeling demonstrated that renal fibroblasts expressed HSPGs on their surface. Furthermore, enzymatic removal of these HS (but not chondroitin sulfate) glycosaminoglycan (GAG) chains, or inhibition of GAG sulfation, abolished the proliferative response of both NRK cells and primary human cortical fibroblasts to FGF-2 but not to platelet-derived growth factor. The addition of conditioned medium, containing HS-GAG fragments, restored the proliferative response to FGF-2, confirming the specificity of the interaction. Finally, the mRNA for all four syndecans was detected in the fibroblasts, and that for syndecan 1 in particular was up-regulated by FGF-2.

CONCLUSIONS

The present study demonstrates that the expression of cell surface HSPG was essential for the proliferation of renal fibroblasts in response to FGF-2, and therefore may play a major role in the development and persistence of a proliferating phenotype during interstitial nephritis.

Evaluation of a hospital diabetes specialist nursing service: a randomized controlled trial

AIMS

To evaluate the effectiveness and cost implications of a hospital diabetes specialist nursing service.

METHODS

We conducted a prospective, open, randomized, controlled trial of standard in-patient care for adults with diabetes, with and without the intervention of a diabetes specialist nursing (DSN) service. The setting was a single UK university hospital.

SUBJECTS

were unselected patients referred to the hospital DSN service. Primary outcome measures were length of hospital stay and patterns of readmission (frequency and time to first readmission). Secondary outcome measures were subjects' diabetes-related quality of life, diabetes knowledge score, satisfaction with treatment, and GP and community care contacts following discharge. Costs were estimated from the hospital and published sources.

RESULTS

Median length of stay was lower in the intervention group (11.0 vs. 8.0 days, P < 0.01). Readmission rates were the same in the two groups (25%), and mean time to readmission was similar in the two groups, although slightly less in the control group (278 vs. 283 days, P = 0.80). The cost per patient for nursing input was 38.94 pounds sterling. However, when the reduced length of stay was accounted for, the intervention produced a mean cost per admission of 436 ponds sterling lower than that of the control group (P = 0.19). Patients in the intervention group were more knowledgeable regarding their diabetes and more satisfied with their care.

CONCLUSIONS

Diabetes specialist nurses are potentially cost saving by reducing hospital length of stay (LOS). There was no evidence of an adverse effect of reduced LOS on re-admissions, use of community resources, or patient perception of quality of care.

Electrically active axons degenerate when exposed to nitric oxide

Axonal degeneration is a major cause of permanent deficit in inflammatory neurological diseases such as multiple sclerosis. Axons undergo degeneration specifically at the site of the inflammatory lesions, suggesting that locally produced inflammatory factors mediate the phenomenon. One such factor is nitric oxide (NO), which we have previously reported can cause reversible conduction block in axons. Here we confirm these observations and extend them to show that axons exhibit the early stages of wallerian degeneration if they are conducting impulses at physiological frequencies while they are exposed to the low micromolar concentrations of NO that are likely to occur at sites of inflammation. Rat dorsal roots were concurrently exposed in vivo to both NO and sustained impulse activity at 1, 50, or 100 Hz. Although our in vivo observations necessarily focused on the more acute responses, morphological examination of exposed roots at the end of the recording period revealed nodal and paranodal changes consistent with acute wallerian degeneration in roots stimulated at 50 or 100 Hz. This interpretation was confirmed in a few experiments that were prolonged to permit more obvious indicators of degeneration to develop. In these experiments the formation of myelin ovoids and frank axonolysis occurred in more than 95% of fibers. Roots stimulated at only 1 Hz appeared normal. We propose that the combination of normal impulse traffic and NO at sites of inflammation may cause axonal degeneration and that electrical activity may therefore be an important factor in causing permanent disability in patients with neuroinflammatory disorders.

Vitamin D nutrition and bone disease in adults

The consequences of vitamin D deficiency upon the skeleton are well known and management in the absence of renal failure is relatively straightforward. Vitamin D, either by mouth or parenterally will correct the deficiency and heal the osteomalacia. The mechanisms underlying the causation of vitamin D deficiency are now better understood and indicate the importance of underlying calcium malabsorption and secondary hyperparathyroidism leading to 1,25(OH)2D-induced catabolism of 25(OH)D and possibly also of vitamin D itself. In such situations, e.g., gastrointestinal and pancreaticobiliary disease, calcium supplementation in addition to vitamin D is indicated. The reasons behind nutritional vitamin D deficiency and the possible role of meat in protecting from osteomalacia await further elucidation, but from epidemiological studies, calcium deficiency, per se, is not implicated in the etiopathogenesis. The concept of vitamin D insufficiency is poorly understood, and difficult to define since a single value or close range of serum 25(OH)D values is unlikely to predict the needs of all subjects. Oral calcium intake and renal function are also likely to be relevant to the level of 25(OH)D which is found to be sufficient or insufficient for any given individual to maintain a normal serum calcium level without secondary hyperparathyroidism. There is increasing evidence that vitamin D insufficiency, by leading to sustained hyperparathyroidism, is prejudicial to the skeleton, particularly cortical bone. Since it is without symptoms until fractures occur, it should be actively sought in those clinical situations now recognized as contributing to risk. It can only be identified by the periodic measurement of serum 25(OH)D and the calcitropic hormones PTH and 1,25(OH)2D. In addition, BMD should be measured in a predominantly cortical site such as the proximal forearm, as well as the more conventional sites of spine and hip. The implications of these recommendations are an increase in the use of assays for PTH and vitamin D metabolites in the groups of subjects discussed in this review. Patients with chronic malabsorption states might reasonably be expected to have measurements performed twice-yearly. When vitamin D insufficiency is found, treatment with either vitamin D, calcium or both will be necessary, depending on the etiology of the insufficiency state in the inividual. In some malabsorptive states, calcium malabsorption is the cause of hyperparathyroidism and oral calcium alone can be used to reverse excess PTH activity in those with an adequate state of vitamin D nutrition. However, even in those vitamin D replete individuals, vitamin D catabolism will be enhanced and a small additional oral dose of vitamin D can do no harm. Regular monitoring of PTH and vitamin D metabolites will remain a necessity to ensure continued efficacy of treatment. Current recommendations for dietary supplements of vitamin D are clearly inadequate [61]. There is compelling evidence for supplements of 800 IU per day in the elderly and other high risk populations. Such a dose is safe and without side effects. The available evidence suggests that this should be combined with calcium supplements of 1200 mg/day [19] and that the current UK recommendations for a daily calcium intake of 700 mg contrast with those from the USA at 1,200 mg for people over 50 years old. Physicians need to be aware of both the small but important problem of vitamin D depletion and osteomalacia with its sometimes ambiguous presentation, and the more common but covert vitamin D (and calcium) insufficiency with its widespread and varied clinical associations.

Light scattering calculations from oleic-acid droplets with water inclusions

We present modeling results in video format showing the changes that occur in the light scattered by a spherical oleic-acid host droplet containing a spherical water inclusion as the inclusion parameters vary. When the system symmetry is broken, a second set of diffraction rings appears on the side opposite the inclusion. The inclusion also acts as a second coherent source, contributing to an interference structure in the scattering pattern, the spatial frequency of which varies with the position of the inclusion.

Effects of clodronate on vertebral fracture risk in osteoporosis: a 1-year interim analysis

The aim of this study was to determine whether clodronate reduced the incidence of vertebral fractures in patients with osteoporosis. We report here the interim analysis after 1 year of a 3-year double-blind placebo-controlled study. The objectives of the interim analysis were to determine whether there was a trend in fracture frequency and to examine the effects of clodronate on bone mineral density (BMD). Patients with densitometrically proven osteoporosis (T-score <-2.5 and <-3 for women and men, respectively) or with at least one prevalent vertebral fracture were recruited to a 3-year double-blind, controlled study. Patients were randomized to three strata, namely women with postmenopausal osteoporosis (stratum I, n = 483), women with secondary osteoporosis (II, n = 110), and men with osteoporosis of any causation (III, n = 84). They received either clodronate 800 mg daily by mouth or an identical placebo, and all patients received a calcium supplement of 500 mg daily. BMD was measured at six monthly intervals, and lateral spine radiographs for vertebral morphometry were obtained at baseline and 1 year. Treatment with clodronate was associated with a significant increase in BMD at the spine of 3.2 +/- 0.3% (p < 0.0001 vs. baseline) compared with a nonsignificant change of 0.5 +/- 0.3% in the placebo group (p < 0.0001 between treatments). At the hip, clodronate was associated with a significant increase in total hip BMD of 1.3 +/- 0.3% (p = 0.018 vs. baseline) compared with a small decrease of 0.4 +/- 0.3% in the placebo group (p = 0.027 for the difference between treatment groups). The mean changes at the spine and hip were similar in all three strata. Incident vertebral fractures were observed in 27 patients at 1 year in the placebo group (9.0%) and in 14 patients receiving clodronate (4.9%) (relative risk 0.54; 95% CI 0.29-1.02; p = 0.07). A trend was observed in all treatment strata. Treatment was well tolerated, with no significant adverse events attributable to clodronate treatment. We conclude that clodronate 800 mg daily is effective in preventing bone loss, and at 1 year, there is a trend consistent with antifracture efficacy in patients with established osteoporosis regardless of causation.

Overexpression of JunB in undifferentiated malignant rat oral keratinocytes enhances the malignant phenotype in vitro without altering cellular differentiation

Our study examined the expression of AP-1 family members in keratinocytes derived from the rat-4NQO model of oral carcinogenesis in which extremes of epithelial differentiation and tumour cell aggressiveness are evident. The constitutive expression of JunB was diminished in the undifferentiated, more aggressive tumour phenotype compared with the well-differentiated, less aggressive keratinocytes, whereas the expression of other AP-1 family members (c-jun, junD, c-fos, fra1, fra2 and fosB) was either very weak or variable. After transfection of the undifferentiated keratinocytes with junB cDNA, clonal populations were isolated that expressed similar levels of JunB protein as the well-differentiated cells. Both untransfected and transfected cell lines were keratin negative and vimentin positive. Increased expression of JunB in the transfected cells resulted in up-regulation of c-Jun and Fra1 and an enhanced AP-1 activity as demonstrated by transcriptional activation of the prototypic AP-1 dependent promoter, MMP-1. JunB transfected cells grew more quickly than vector-only controls and were refractory to the growth inhibitory effects of TGF-beta1. Over-expression of JunB resulted in the elevated expression of the AP-1 dependent proteinase, MMP-9, whereas the expression of the AP-1 independent enzyme, MMP-2, was unaffected. JunB transfected keratinocytes were highly invasive in an in vitro assay of tumour cell invasion compared with vector controls. The results indicate that increased expression of JunB above baseline levels in undifferentiated rat keratinocytes does not alter epithelial differentiation but enhances the malignant phenotype in vitro, possibly by altering the dynamics of the AP-1 complex.

Clinical relevance of the primary findings of the MTA: success rates based on severity of ADHD and ODD symptoms at the end of treatment

OBJECTIVES

To develop a categorical outcome measure related to clinical decisions and to perform secondary analyses to supplement the primary analyses of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA).

METHOD

End-of-treatment status was summarized by averaging the parent and teacher ratings of attention-deficit/hyperactivity disorder and oppositional defiant disorder symptoms on the Swanson, Nolan, and Pelham, version IV (SNAP-IV) scale, and low symptom-severity ("Just a Little") on this continuous measure was set as a clinical cutoff to form a categorical outcome measure reflecting successful treatment. Three orthogonal comparisons of the treatment groups (combined treatment [Comb], medication management [MedMgt], behavioral treatment [Beh], and community comparison [CC]) evaluated hypotheses about the MTA medication algorithm ("Comb + MedMgt versus Beh + CC"), multimodality superiority ("Comb versus MedMgt"), and psychosocial substitution ("Beh versus CC").

RESULTS

The summary of SNAP-IV ratings across sources and domains increased the precision of measurement by 30%. The secondary analyses of group differences in success rates (Comb = 68%; MedMgt = 56%; Beh = 34%; CC = 25%) confirmed the large effect of the MTA medication algorithm and a smaller effect of multimodality superiority, which was now statistically significant (p < .05). The psychosocial substitution effect remained negligible and nonsignificant.

CONCLUSION

These secondary analyses confirm the primary findings and clarify clinical decisions about the choice between multimodal and unimodal treatment with medication.

Impairment and deportment responses to different methylphenidate doses in children with ADHD: the MTA titration trial

OBJECTIVE

Results of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA) were analyzed to determine whether a double-blind, placebo-controlled methylphenidate (MPH) titration trial identified the best MPH dose for each child with attention-deficit/hyperactivity disorder (ADHD).

METHOD

Children with ADHD assigned to MTA medication treatment groups (n = 289) underwent a controlled 28-day titration protocol that administered different MPH doses (placebo, low, middle, and high) on successive days.

RESULTS

A repeated-measures analysis of variance revealed main effects for MPH dose with greater effects on teacher ratings of impairment and deportment (F3 = 100.6, n = 223, p = .0001; effect sizes 0.8-1.3) than on parent ratings of similar endpoints (F3 = 55.61, n = 253, p = .00001; effect sizes 0.4-0.6). Dose did not interact with period, dose order, comorbid diagnosis, site, or treatment group.

CONCLUSIONS

The MTA titration protocol validated the efficacy of weekend MPH dosing and established a total daily dose limit of 35 mg of MPH for children weighing less than 25 kg. It replicated previously reported MPH response rates (77%), distribution of best doses (10-50 mg/day) across subjects, effect sizes on impairment and deportment, as well as dose-related adverse events.

Myotube formation is delayed but not prevented in MyoD-deficient skeletal muscle: studies in regenerating whole muscle grafts of adult mice

We compared the time course of myogenic events in vivo in regenerating whole muscle grafts in MyoD(-/-) and control BALB/c adult mice using immunohistochemistry and electron microscopy. Immunohistochemistry with antibodies to desmin and myosin revealed a striking delay by about 3 days in the formation of myotubes in MyoD(-/-) autografts compared with BALB/c mice. However, myotube formation was not prevented, and autografts in both strains appeared similar by 8 days. Electron microscopy confirmed myotube formation in 8- but not 5-day MyoD(-/-) grafts. This pattern was not influenced by cross-transplantation experiments between strains examined at 5 days. Antibodies to proliferating cell nuclear antigen demonstrated an elevated level of replication by MyoD(-/-) myoblasts in autografts, and replication was sustained for about 3 days compared with controls. These data indicate that the delay in the onset of differentiation and hence fusion is related to extended proliferation of the MyoD(-/-) myoblasts. Overall, although muscle regeneration was delayed it was not impaired in MyoD(-/-) mice in this model.

Induction of hyaluronan metabolism after mechanical injury of human peritoneal mesothelial cells in vitro

BACKGROUND

Hyaluronan (HA) is an important extracellular matrix component that is involved in cell movement and tissue repair. In vertebrates, HA synthase genes (HAS 1, HAS 2, and HAS 3) that control the synthesis of HA have been identified. In this article, we investigated HA synthesis in the response of human peritoneal mesothelial cells (HPMCs) to injury.

METHODS

The expression of HAS 1, HAS 2, and HAS 3 mRNA and the synthesis of [(3)H]-labeled HA were examined in an in vitro model of peritoneal mesothelial cell damage. The staining for uridine diphosphoglucose dehydrogenase, a key enzyme in the synthesis of HA, and biotinylated HA-binding protein was used to determine the cellular location of HA synthesis and its site of deposition.

RESULTS

Growth-arrested human HPMCs expressed low levels of mRNA for HAS 2 and HAS 3 but not HAS 1. Following injury to the monolayer, HAS 2 was up-regulated by 6 hours, reaching maximal expression between 12 and 24 hours. In contrast, the expression of HAS 3 was down-regulated. During the same time period, synthesis of HA was increased in the injured monolayer. This synthetic activity appeared to be restricted to cells at the edge of the wound and to cells entering the wound. In a separate series of experiments, the addition of HA to the injured monolayer at a concentration range found in peritoneal fluid (50 to 3300 ng/mL) increased the migration of cells into the wound in a dose-dependent manner.

CONCLUSIONS

These studies provide evidence that HA is an important component of peritoneal mesothelial cell migration. The results also suggest that in this process, there is differential regulation of HAS gene expression and that the synthesis of HA is limited to cells located at the leading edge of the wound.

Characterization of the interaction of zopiclone with gamma-aminobutyric acid type A receptors

Zopiclone is a cyclopyrrolone that is used clinically as a hypnotic. Although this drug is known to interact with neuronal gamma-aminobutyric acid type A receptors, its binding site(s) within the receptor oligomer has been reported to be distinct from that of the classical benzodiazepines. After photoaffinity labeling with flunitrazepam, receptors in rat cerebellar membranes showed differentially reduced affinity for flunitrazepam and zopiclone by 50- and 3-fold, respectively. Because histidine 101 of the alpha-subunit is a major site of photolabeling, we have made specific substitutions of this residue and studied the consequences on the binding properties of zopiclone and diazepam using recombinant alpha1beta2gamma2-receptors transiently expressed in tsA201 cells. Both compounds showed similar binding profiles with receptors containing mutated alpha-subunits, suggesting a similar interaction with the residue at position 101. At alpha1beta2gamma3-receptors, flunitrazepam affinity was dramatically decreased by approximately 36-fold, whereas the affinity for zopiclone was decreased only 3-fold, suggesting a differential contribution of the gamma-subunit to the binding pocket. Additionally, we used electrophysiological techniques to examine the contribution of the gamma-subunit isoform in the receptor oligomer to ligand recognition using recombinant receptors expressed in Xenopus oocytes. Both compounds are agonists at alpha1beta2gamma2- and alpha1beta2gamma3-receptors, with flunitrazepam being more potent but less efficacious. In summary, these data suggest that histidine 101 of the alpha1-subunit plays a similar role in ligand recognition for zopiclone, diazepam, and flunitrazepam.

Production and regulation of matrix metalloproteinases and their inhibitors by human peritoneal mesothelial cells

OBJECTIVE

Human peritoneal mesothelial cells (HPMC) are likely to be involved in maintenance of the peritoneal membrane. We determined whether these cells were able to synthesize the matrix degrading enzymes, matrix metalloproteinases (MMPs), likely to be responsible for the breakdown of this membrane, and whether this secretion could be modulated by cytokines involved in the inflammatory response.

DESIGN

MMP activity in conditioned medium of growth-arrested HPMC was measured by zymography. Cultures were incubated in the presence and absence of the cytokines transforming growth factor-beta (TGFbeta) and interleukin (IL)-1beta in order to determine the effects of these cytokines on this process. The mRNA for these MMPs, together with that of their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs), was also examined by reverse transcriptase polymerase chain reaction

RESULTS

HPMC were shown to constitutively secrete the metalloproteinases MMP-2 and MMP-3 in vitro. In response to the proinflammatory cytokine IL-1beta , the protein and mRNA for MMP-9 was induced, while secretion of MMP-2 was unaltered. Similarly, the mRNA for MMP-3 was also increased relative to actin following the addition of IL-1beta. TGFbeta was shown to slightly induce the secretion of MMP-2 together with the mRNA for TIMP I, TIMP II, and, to a greater extent, TIMP III. Used peritoneal dialysate was also shown to induce MMP-9 secretion, and this effect was blocked by the co-incubation of IL-1 receptor antagonist. The secretion of enzyme activity was shown to be from the apical surface of the cells.

CONCLUSION

HPMC have the ability to control the accumulation of extracellular matrix by secreting the matrix degrading molecules MMP-2, MMP-3, and MMP-9. In addition, the secretion of these enzymes, together with that of their inhibitors (TIMPs) is regulated by the cytokines IL-1beta and TGFbeta. This process is likely to be important in both the normal maintenance of the integrity of the peritoneal membrane and in the changes that occur following prolonged peritoneal dialysis.

Religiosity and substance use and abuse among adolescents in the National Comorbidity Survey

OBJECTIVE

To replicate previous findings among adults of an inverse association between religiosity and substance use among a nationally representative sample of adolescents.

METHOD

Subjects were 676 (328 female and 348 male) adolescents in the National Comorbidity Survey who were assessed for substance use and abuse with the Composite International Diagnostic Interview. Religiosity was assessed through affiliation with religious denomination and through response to 7 questions concerning belief and practice.

RESULTS

Confirmatory factor analyses replicated in adolescents the 2 religiosity factors of personal devotion and personal conservatism previously identified by Kendler among adults, although the 2 factors were more highly correlated in adolescents than in adults. Personal devotion (a personal relationship with the Divine) and affiliation with more fundamentalist religious denominations were inversely associated with substance use and substance dependence or abuse across a range of substances (alcohol, marijuana, cocaine, or any contraband drug). Personal conservatism (a personal commitment to teaching and living according to creed) was inversely associated with use of alcohol only.

CONCLUSION

Low levels of religiosity may be associated with adolescent onset of substance use and abuse.

How specific is specific impairment?

OBJECTIVE

To describe the usefulness of impairment items placed at the end of each diagnostic section of a structured instrument (the Diagnostic Interview Schedule for Children Version 2.3) in an attempt to link impairment to specific diagnoses.

METHOD

Data from 3 sites of the Methods for the Epidemiology of Child and Adolescent Mental Disorders Study were used to assess the reliability of the specific impairment measures by diagnosis, the extent to which global and specific measures of impairment impact on prevalence rates, the concordance between global and specific impairment, and the degree to which there may be a "halo effect" among specific impairment ratings.

RESULTS

Test-retest reliability was better for parent than youth ratings. Fewer children were rated as impaired on well-validated global scales than on specific impairment ratings, suggesting that the threshold for specific ratings needs to be reevaluated. Agreement between specific and global ratings was poor. Most subjects with 2 or more diagnoses for which impairment was attributed to one diagnosis also had impairment attributed to other diagnoses for which they met symptom criteria, suggesting a halo effect in these ratings of specific impairment.

CONCLUSIONS

Impairment measures are important in diagnostic assessments to distinguish those individuals whose psychopathology is of clinical significance. Specific impairment ratings used in structured instruments could be improved by including parameters of impairment that are diagnosis-specific.