Multidisciplinary approach for prescriptive management of mineral and bone metabolism in chronic kidney disease: development of a dietetic led protocol.

BACKGROUND: A number of mineral metabolism abnormalities occur as kidney function declines, these include hyperphosphatemia, hyperparathyroidism and altered vitamin D metabolism. These derangements are associated with increased morbidity and mortality amongst the chronic kidney disease patient group. Treatment requires a multidisciplinary team approach in which the dietitian plays a pivotal role. OBJECTIVES: The development of protocols to aid implementation of various international, national and local treatment strategies is described. Audit the protocol to evaluate their clinical effectiveness. RESULTS: A prescriptive Protocol for the management of mineral and bone metabolism abnormalities in chronic kidney disease was developed and implemented. Initial audit findings suggest the protocol has had a positive effect on the control of phosphate, corrected calcium and parathyroid (PTH) levels. CONCLUSION: The development and implementation of a dietetic-led prescriptive therapy protocol allows dietitians and clinicians to adopt an integrated approach for the diagnosis and timely management of these complicated conditions.

Analysis of rt-PA infusion in tunnelled dialysis catheters.

Urokinase and streptokinase are commonly used thrombolytic agents for obstructed central venous catheters. Although proven to be efficacious, these agents have the potential to induce fibrin breakdown and streptokinase cannot be used repeatedly due to its allergenic nature. Documented evidence suggests that urokinase is safe and effective (> 70% efficacy for catheter installation) however further evidence points to tissue-type plasminogen activator (rt-PA) achieving as much as 98% success. This study reports on the safety and efficacy of alternative catheter thrombolysis, namely rt-PA and evaluates the efficacy of rt-PA. 20 patients required 57 infusions in 38 lumens between 01/01/02 to 01/09/03. For completely blocked lines rt-PA was infused at 2 mg/hr for 4 hours achieving 85% success rate. For inadequate flow (< 250 mls/min) rt-PA was infused at 1 mg/hr for 4 hours achieving 88% success rate.

Restoration of flow following haemodialysis catheter thrombus. Analysis of rt-PA infusion in tunnelled dialysis catheters.

PROBLEM: Urokinase and streptokinase are commonly used thrombolytic agents for obstructed central venous catheters. Although proven to be efficacious, these agents have the potential to induce fibrin breakdown and streptokinase cannot be used repeatedly because of its allergenic nature. Published evidence suggests that Urokinase is safe and effective (>70% efficacy for catheter installation) and that Tissue-type plasminogen activator (rt-PA) can achieve as much as 98% success. OBJECTIVE: To describe our experience with and our protocol for the use of rt-PA as an alternative agent for catheter thrombolysis. DESIGN: Investigation of a cohort of haemodialysis patients with tunnelled central venous catheter (SPCVC) placed between December 2001 to August 2003 and who developed catheter thrombus (female, n = 8: male, n = 12). Each patient was given an infusion of between 1 and 2 mg rt-PA/h for 4 h. The dose was dependent on partial or total line obstruction. The technical success of rt-PA is defined as returning catheter blood flow to >250 mL/min for a 4-h period. FINDINGS: Twenty patients required 57 infusions in 38 lumens between 01/01/02 to 01/09/03. For completely blocked lines rt-PA was infused at 2 mg/h for 4 h achieving 85% success rate. For inadequate flow (<250 mL/min) rt-PA was infused at 1 mg/h for 4 h achieving an 88% success rate. CONCLUSION: Rt-PA administered at 2 mg/h for blocked lines effectively restores haemodialysis catheter patency, and at 1 mg/h for sluggish lines is also effective in restoring blood flow through catheters.

Impact of stepped verbal and written reinforcement of fluid balance advice within an outpatient haemodialysis unit: a pilot study.

BACKGROUND: The present pilot study assesses a programme of verbal and written fluid balance advice within an out-patient haemodialysis unit. METHODS: Twenty-one haemodialysis patients were followed over three separate 6-week periods. Each 6-week period assessed dietetic and nursing educational input using a stepped approach with interdialytic weight gain (IDWG) as a barometer of patient compliance. Weight gain was statistically examined using the non-parametric Friedman test. RESULTS: Forty-eight per cent of the sample group demonstrated an overall improvement in mean weight gain; however, this was not statistically significant (P=0.504). CONCLUSION: The pilot study suggests that further studies with greater numbers and a control group would have a useful contribution to make in this field.

Consensus conference: acitretin in combination with UVB or PUVA in the treatment of psoriasis.

Although adjunctive treatment with retinoids in concert with either psoralen-ultraviolet A (PUVA) or ultraviolet B (UVB) phototherapy has been a treatment option for chronic, moderate to severe plaque psoriasis for nearly two decades, acitretin-UV therapy is an underutilized therapeutic modality. According to a recent member survey by the National Psoriasis Foundation, many psoriasis patients are frustrated with available treatment options, which they perceive as ineffective, inconvenient, and/or excessively conservative. Treatment of psoriasis with acitretin in concert with UVB or PUVA is emerging as a viable clinical strategy. Compared with either acitretin or UV light monotherapy alone, the combination regimen enhances efficacy and limits treatment frequency, duration, and cumulative doses. These effects translate into care that is more effective, better tolerated, more convenient, less costly, and, perhaps, safer during long-term treatment than phototherapy alone. Drawing from an extensive literature search and the expertise of its participants, this consensus conference advances clinical recommendations as well as "clinical pearls" for health providers who treat patients with chronic, moderate to severe plaque psoriasis and suggests avenues for future research.

Cellular localization of BM88 mRNA in paraffin-embedded rat brain sections by combined immunohistochemistry and non-radioactive in situ hybridization.

With the advent of gene cloning and sequencing, it has become increasingly common to identify novel genes for which no antibody is available. The best approach to study the expression and the distribution of these new genes is by in situ hybridization. One of the challenges with this method is to define the exact cellular subtype where the gene of interest is expressed. Conventional isotopic in situ hybridization methods lack precision for cellular identification because radioactive probes often result in a scattered signal. To identify the exact cellular subtype expressing BM88, we established a rapid colocalization method using non-isotopic in situ hybridization followed by chromogenic immunohistochemistry on the same tissue section. We demonstrated that BM88, which was identified from subtractive hybridization experiments between normal and ischemic tolerant brain tissue, was expressed exclusively in neurons in normal adult rat brain. Paraffin-embedded tissue was used as it resulted in better preservation of tissue and cellular morphology, thus allowing for more accurate histological localization of gene expression. It also allowed for retrospective studies on a number of archived tissue samples.

The relationship between interdialytic weight gain and patient compliance. A single centred cohort study (n=21).

Haemodialysis patients are subject to many restrictions and face a lifetime attempting to adhere to various regimes. This small study was designed to explore the relationship between fluid gain, compliance and staff reinforcement. This was achieved by measuring dietetic and nursing educational input using interdialytic weight gain as a barometer of patient compliance. This study suggests renal nurses, dietitians and other members of the multi-disciplinary team may have less influence than previously assumed.

Urinary catecholamine excretion in relation to renal function.

The urinary excretions of the free catecholamines noradrenaline, adrenaline and dopamine were measured in 50 patients (33 men and 17 women) with chronic renal failure. Stability studies showed that the catecholamines were stable in unacidified urine as long as the pH was not greater than 7.5 and the urine was acidified within 2-3 h of collection. The outputs of noradrenaline and dopamine correlated positively with creatinine clearance and in patients with clearances above 40 mL/min were similar to those in healthy volunteers (n = 20). However, adrenaline output was not correlated with creatinine clearance although it was lower in patients with renal failure compared with healthy volunteers. The urinary free catecholamine output during the first 10 days after a renal transplant was significantly less than normal, presumably because renal function was still impaired. However, in patients treated with cyclosporin A (CyA) combined with prednisolone the catecholamine excretion was lower compared with those treated with CyA and azathioprine. Impairment in renal function can have a marked effect on the output of free catecholamines and must be borne in mind when interpreting values that may have pathological significance.

Intermittent administration of parathyroid hormone (1-34) stimulates matrix metalloproteinase-9 (MMP-9) expression in rat long bone.

Intermittent doses of parathyroid hormone (PTH) stimulate bone formation in animals and humans, but the molecular mechanisms underlying this phenomenon are not understood. Bone formation culminates with the expression of type I collagen, osteocalcin, and alkaline phosphatase, but genes that initiate and support the anabolic response are not known. To identify novel PTH-regulated genes in bone during the anabolic response, we used differential display-polymerase chain reaction (DDRT-PCR) to analyze RNA from young male rats injected with either human PTH (1-34) or vehicle control, once daily for 5 days. Total RNA was isolated from the distal femur metaphysis at 1, 6, and 48 h after the final injection and subjected to DDRT-PCR. We identified three PTH-responsive transcripts as matrix metalloproteinase-9 (MMP-9), creatine kinase, and the alpha1 (I) polypeptide chain (COL1A1) of type I collagen. The concomitant upregulation of MMP-9 and COL1A1 during bone formation was particularly intriguing. Further characterization of MMP-9 expression revealed that it was localized to osteoblasts, osteocytes, megakaryocytes, and cells of the bone marrow in the rat distal femur metaphysis. Northern analysis for MMP-9 expression in other tissues indicated that this transcript was present in the kidney and brain. In vitro, PTH regulated the protein synthesis of MMP-9 by osteoblasts of the primary spongiosa. We propose that PTH may promote bone formation by mediating the subtle variation in MMP activities, thus preparing the extracellular matrix for the subsequent bone cell migration and deposition of new osteoid.

Microvascular endothelial activation in the skeletal muscles of patients with multiple organ failure.

The relationship between microvascular damage and the presence of muscle fibre atrophy and necrosis has been investigated in skeletal muscle biopsies taken from 57 patients with multiple organ failure. Immunohistochemical studies showed no loss of capillaries and no luminal thrombosis, while neutrophil leucocytes were more prevalent in the patients' biopsies than in controls. Deposition of the complement membrane attack complex (C5-9MAC) in capillaries was observed in 41% of cases. Endothelial activation was suggested by an increased intensity of expression of ICAM-1, and by an increased proportion of capillaries expressing P selectin and E selectin, although this was not directly associated with neutrophil accumulation. Endothelial swelling was present in many biopsies with 38% of the biopsies having larger capillary profiles on immunohistochemical labelling for von Willebrand factor (vWF), thrombomodulin and CD34, and on Ulex europaeus agglutinin 1 binding. Endothelial swelling was confirmed by image analysis and morphometric evaluation of capillary ultrastructure, however, the capillary luminal area was not reduced as the capillaries were dilated. Increased vWF labelling was associated with C5-9MAC deposition and with fibre necrosis, but the vascular changes were not related to fibre atrophy nor to clinical indices of the severity of the patients' illness. The results suggest that microvascular damage and ischaemia may not be major factors in the pathogenesis of muscle fibre damage in multiple organ failure, but that endothelial activation is a common occurrence. The variability in the patterns of markers of endothelial activation, and the small proportion of capillaries affected, may reflect the complexity of the endothelial response to circulating or locally produced cytokines.

Analysis of differential gene expression in rat tibia after an osteogenic stimulus in vivo: mechanical loading regulates osteopontin and myeloperoxidase.

The skeleton has the ability to alter its mass, geometry, and strength in response to mechanical stress. In order to elucidate the molecular mechanisms underlying this phenomenon, differential display reverse transcriptase-polymerase chain reaction (DDRT-PCR) was used to analyze gene expression in endocortical bone of mature female rats. Female Sprague-Dawley rats, approximately 8 months old, received either a sham or bending load using a four-point loading apparatus on the right tibia. RNA was collected at 1 h and 24 h after load was applied, reverse-transcribed into cDNA, and used in DDRT-PCR. Parallel display of samples from sham and loaded bones on a sequencing gel showed several regulated bands. Further analysis of seven of these bands allowed us to isolate two genes that are regulated in response to a loading stimulus. Nucleotide analysis showed that one of the differentially expressed bands shares 99% sequence identity with rat osteopontin (OPN), a noncollagenous bone matrix protein. Northern blot analysis confirms that OPN mRNA expression is increased by nearly 4-fold, at 6 h and 24 h after loading. The second band shares 90% homology with mouse myeloperoxidase (MPO), a bactericidal enzyme found primarily in neutrophils and monocytes. Semiquantitative PCR confirms that MPO expression is decreased 4- to 10-fold, at 1 h and 24 h after loading. Tissue distribution analysis confirmed MPO expression in bone but not in other tissues examined. In vitro analysis showed that MPO expression was not detectable in total RNA from UMR 106 osteoblastic cells or in confluent primary cultures of osteoblasts derived from either rat primary spongiosa or diaphyseal marrow. Database analysis suggests that MPO is expressed by osteocytes. These findings reinforce the association of OPN expression to bone turnover and describes for the first time, decreased expression of MPO during load-induced bone formation. These results suggest a role for both OPN and MPO expression in bone cell function.

Obtaining the optimal treatment outcome with tazarotene.

Tazarotene topical gel (Tazorac) is a vitamin A derivative and the first topical retinoid to demonstrate therapeutic success in treating plaque-type psoriasis. It has been available in the United States since 1997. Tazarotene offers long-term remission in many patients and may be used in combination with corticosteroids and UVB therapy for even better results. Due to its potency as a vitamin derivative, tazarotene is also associated with irritation in some patients. Patients must be educated about proper application of the drug and realistic expectations for treatment outcome.

Muscle fibre atrophy in critically ill patients is associated with the loss of myosin filaments and the presence of lysosomal enzymes and ubiquitin.

Muscle wasting and weakness are common features of patients with critical illnesses, and may impair their recovery. This study examines whether cytoskeletal and contractile proteins are damaged, and which proteolytic mechanisms might be involved, in the muscle fibre atrophy or necrosis associated with the acute myopathy of critically ill patients. Ninety-eight muscle biopsies were obtained by the conchotome method from 57 critically ill patients and examined morphometrically and by immunohistochemical labelling. Sequential biopsies showed a mean reduction in fibre cross-sectional areas of 3-4% per day. More intense immunolabelling for desmin was seen in the smaller fibres of 52% of the biopsies, while immunolabelling for dystrophin, actin and myosin heavy chains was maintained. Myosin ATPase activity was weak in the smaller fibres in some biopsies, and electron microscopy showed the loss of myosin filaments in atrophic fibres. These changes suggest that loss of the filamentous structure of myosin, without degradation of the immunolabelled epitopes, leads to the collapse of the intermyofibrillar desmin network. Fibres with abnormal desmin labelling showed increased cathepsin B, lysozyme and ubiquitin immunolabelling. Nine cases showed increased immunolabelling for heat shock protein 72. The changes in desmin immunolabelling were more prevalent in patients with higher APACHE II scores on admission, but were not related to other clinical features. The results indicate that fibre atrophy is associated with myosin filament depolymerization and the presence of several proteolytic enzymes. In our study, these changes occurred in patients who were critically ill but who did not receive large doses of steroids or neuromuscular blocking agents.

New treatment options for psoriasis.

Psoriasis is a chronic genetic disease characterized by hyperproliferation and inflammation of the epidermis and dermis. Presently there is no cure for psoriasis, only treatments to alleviate the symptoms. Tazarotene (Tazorac) is a new vitamin A derivative and the first topical retinoid to demonstrate therapeutic success in treating plaque-type psoriasis. This article will introduce you and your patients to the safe and effective use of tazarotene.

UVB therapy: dermatology nursing considerations.

Each patient responds uniquely to phototherapy treatment. Not every patient can tolerate daily treatment. Different areas of the body require different amounts of light in order to clear. Precise documentation of erythema is important for both treatment and legal reasons. A negative response to UVB therapy can be from either ineffective treatment or an adverse reaction to UVB.

Parathyroid hormone (1-34)-mediated interleukin-6 induction.

Parathyroid hormone (PTH) functions in part by regulating osteoblast cytokine expression. We recently demonstrated that PTH induced a rapid and transient increase in interleukin-6 (IL-6) mRNA expression in rat bones in vivo. To determine the molecular basis of this effect, we analyzed the human IL-6 promoter fused (-1,179 to +9) with the chloramphenicol acetyltransferase (CAT) reporter gene in stable transfections into human osteoblast-like osteosarcoma SaOS-2 cells. We compared the effects of PTH on IL-6 expression with adenylate cyclase activator forskolin, PKC activator phorbol 12-myristate 13-acetate (PMA), calcium ionophore A23187, interleukin-1 alpha (IL-1 alpha), prostaglandin E-2 (PGE-2), RS-66271 (a parathyroid hormone-related peptide analog), and platelet-derived growth factor-BB (PDGF-BB). Analyses of cell clones showed that IL-6 promoter expression was extremely low in the unstimulated state. Exposure to PTH (0.001-100 nM) for 12 h stimulated CAT expression in a dose-dependent manner (200-500% of control). Treatment with IL-1 alpha was more potent than PTH in inducing transcription of the IL-6 promoter (900-1,000%). Activation of the cAMP-PKA pathway by treatment with forskolin induced a comparable level of induction with PTH. Together, the effects of PTH and forskolin were additive. RS-66271, previously shown to have PTH-like effects, induced a comparable level of IL-6 promoter expression. When examined together, PTH+RS-66271 effects were comparable to PTH effects alone. Exposure to PGE-2, PMA, PDGF-BB, or A23187 for 12 h did not significantly alter IL-6 promoter expression. These results demonstrate PTH, forskolin, the PTHrP analog RS-66271, and IL-1 alpha stimulate IL-6 expression by stimulating gene transcription. The response to forskolin suggests that the messenger system mediated by PKA is sufficient to induce IL-6 expression.

Detection of osteopontin in calcified human aortic valves.

Cardiac valve calcification often results in obstruction of blood flow, which eventually leads to valve replacement. The molecular mechanisms resulting in valve calcification are unknown. Collagen and specific bone matrix proteins are thought to provide the framework for ectopic tissue calcification. This investigation was performed to determine whether the bone matrix protein osteopontin was present in calcified human aortic valves. Proteins extracted from human aortic valve tissue were subjected to polyacrylamide gel electrophoresis followed by Western blotting, using polyclonal antibodies directed against osteopontin. Fresh frozen tissue sections were also screened for osteopontin and macrophages using immunohistochemical techniques. Osteopontin was present in both heavily and minimally calcified aortic valves and absent in noncalcified purely regurgitant or normal aortic valves by both radioimmunoassay (n = 16) and immunohistochemical techniques (n = 8). Osteopontin colocalized with valvular calcific deposits, and macrophages were identified in the vicinity of osteopontin. These results, in addition to showing that osteopontin is present in calcified human aortic valves, suggest that osteopontin is a regulatory protein in pathological calcification. Identification of the cells producing osteopontin in abnormal cardiac valves and of proximate stimuli for its secretion may lead to novel therapeutic strategies to prevent and/or reverse calcific valve disease.

Psoralen photochemotherapy.

Psoralens and sunlight have been used by the Egyptians and Indians for hundreds of years for treating vitiligo. The combination of oral psoralens and artificial ultraviolet A (PUVA) therapy was approved for managing severe psoriasis by the Food and Drug Administration in 1982. Since then, PUVA therapy has been an effective modality for treating many cutaneous conditions (psoriasis, atopic dermatitis, vitiligo, and mycosis fungoides). However, proper knowledge and administration of PUVA therapy are vital to treatment success and reducing side effects.