Latest on human research

Alkaline phosphatase normalization is associated with better prognosis in primary sclerosing cholangitis

noreply@blogger.com (Diagnostic Research) — Mon, 09 May 2011 20:51:00 +0000

Abstract
Background
Primary sclerosing cholangitis results in elevated but fluctuating serum alkaline phosphatase levels that occasionally return to normal.

Aims
To investigate the frequency of normalization of alkaline phosphatase in newly diagnosed primary sclerosing cholangitis patients and the subsequent clinical outcomes.

Methods
Records of newly diagnosed primary sclerosing cholangitis patients were examined retrospectively for laboratory values and clinical end points (cholangiocarcinoma, liver transplantation and death) within 10 years of diagnosis. Data from a recent prospective ursodeoxycholic acid treatment trial were also studied.

Results
Eighty-seven patients met the inclusion criteria. Normalization of alkaline phosphatase was seen in 35 (40%) patients. Five (14%) patients with normalization reached an end point whereas 17 (33%) of the patients with persistent elevation reached an end point (P = 0.02). Ursodeoxycholic acid was used similarly by both groups. When the investigative criteria were applied to a prospective trial, there was again a significant relationship between normalization of alkaline phosphatase and survival in patients receiving ursodeoxycholic acid (P < 0.01) and the placebo group (P = 0.02).

Conclusions
Serum alkaline phosphatase was found to normalize in a high proportion of newly diagnosed primary sclerosing cholangitis patients. This was significantly associated with a better prognosis in a retrospective cohort and when data from a prospective treatment trial was evaluated

Digestive and Liver Disease
Volume 43, Issue 4, April 2011, Pages 309-313

Serum alkaline phosphatase changes predict survival independent of PSA changes in men

noreply@blogger.com (Diagnostic Research) — Mon, 15 Nov 2010 19:56:00 +0000

U.S. Oncology Research, Inc., Texas Oncology and Baylor College of Medicine, Webster, TX 77598, USA.

The association of a change in serum alkaline phosphatase (ALP) with overall survival OS in men with metastatic castration-resistant prostate cancer (CRPC) receiving chemotherapy is unknown. We evaluated the association of changes in ALP within 90 days with OS in men with CRPC and bone metastases treated with docetaxel or mitoxantrone in the TAX327 trial.

Eligible patients included those with bony metastatic disease, baseline ALP ≥ 120 u/L (upper limit of normal) and ≥2 post-therapy measurements of ALP available. Survival was estimated using the Kaplan-Meier method and prognostic potential of change in ALP was evaluated using Cox proportional hazards regression. Surrogacy was calculated by the Likelihood Reduction Factor.

601 patients met the eligibility criteria. By day 90, 159 patients had ALP normalization (< 120 u/L) and 442 patients did not normalize. Normalization of ALP remained prognostic for OS after adjusting for PSA decline ≥ 30% by day 90 (HR 0.79, 95% CI = 0.65-0.97, P = 0.022). Increase in ALP remained prognostic for OS when adjusting for PSA increase ≥ 50% by day 90 (HR 1.69, 95% CI = 1.33-2.14, P < 0.001). ALP changes did not meet criteria for surrogacy for OS.

For men with CRPC, bone metastasis and high baseline ALP receiving docetaxel or mitoxantrone chemotherapy, normalization of ALP by day 90 was predictive of better survival independent of ≥30% PSA declines. An increase in ALP by day 90 was also predictive of poor survival independent of ≥50% PSA increase. Given the ready availability of ALP, the validation of our data is warranted.

Written by:
Sonpavde G, Pond GR, Berry WR, de Wit R, Armstrong AJ, Eisenberger MA, Tannock IF

Alkaline Phosphatase May Be a Marker of Inflammation in CKD Patients

noreply@blogger.com (Diagnostic Research) — Wed, 15 Sep 2010 19:33:00 +0000

ORLANDO, Fla.—Serum alkaline phosphatase may be a marker for inflammation in CKD patients, according to data presented here at the National Kidney Foundation's 2010 Spring Clinical Meetings.

In a study of more than 900 adults with CKD (mean age 69.6 years, 37% men, 7% African-American) who participated in the Third National Health and Nutrition Examination Survey, researchers at the University of Utah School of Medicine in Salt Lake City found that higher serum alkaline phosphatase levels were associated with lower levels of serum 25-hydroxyvitamin D (25-D). Subjects in the highest quartile of serum alkaline phosphatase had a 2.54-fold higher odds of elevated C-reactive protein levels after adjusting for serum 25-D levels. “Therefore, serum alkaline phosphatase might be a marker of inflammatory milieu in the CKD population,” the investigators concluded.

By: Jody A. Charnow

Tumor necrosis factor-α increases alkaline phosphatase expression in vascular smooth muscle cells via MSX2 induction

noreply@blogger.com (Diagnostic Research) — Thu, 28 Jan 2010 18:37:00 +0000

Hye-Lim Leea, Kyung Mi Wooa, Hyun-Mo Ryooa and Jeong-Hwa Baek, a,

a Department of Cell and Developmental Biology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea

Abstract
Vascular calcification is implicated in many diseases including atherosclerosis and diabetes. Tumor necrosis factor-α (TNF-α) has been shown to promote vascular calcification both in vitro and in vivo. However, the molecular mechanism of TNF-α-mediated vascular calcification has not yet been fully defined. Therefore, in this study, we aimed to investigate whether MSX2 acts as a crucial regulator in TNF-α-induced vascular calcification and to define the regulatory mechanism of MSX2 induction in human vascular smooth muscle cells (VSMCs).

TNF-α increased the expression of osteogenic marker genes including RUNX2, osterix, alkaline phosphatase (ALP), and bone sialoprotein, and it also promoted matrix mineralization in VSMCs. In addition, TNF-α enhanced MSX2 expression in a dose- and time-dependent manner. MSX2 over-expression alone induced ALP expression, whereas knockdown of MSX2 with small interfering RNA completely blocked TNF-α-induced ALP expression.

New protein synthesis was dispensable for MSX2 induction by TNF-α, and the inhibition of NF-κB by BAY-11-7082 or by dominant negative IκBα abolished the TNF-α-directed induction of MSX2 expression. However, inhibition of NADPH oxidase did not affect MSX2 expression.

In conclusion, our study suggests that TNF-α directly induces MSX2 expression through the NF-κB pathway, which in turn induces expression of ALP, a key molecule in mineralization, in VSMCs

Alkaline phosphatase treatment improves renal function in severe sepsis or septic shock patients

noreply@blogger.com (Diagnostic Research) — Tue, 24 Nov 2009 17:40:00 +0000

Objective: Alkaline phosphatase (AP) attenuates inflammatory responses by lipopolysaccharide detoxification and may prevent organ damage during sepsis. To investigate the effect of AP in patients with severe sepsis or septic shock on acute kidney injury.

Design and Setting: A multicenter double-blind, randomized, placebo-controlled phase IIa study (2:1 ratio).

Patients: Thirty-six intensive care unit patients (20 men/16 women, mean age 58 ± 3 years) with a proven or suspected Gram-negative bacterial infection, ≥2 systemic inflammatory response syndrome criteria (<24 hours), and <12 hours end-organ dysfunction onset were included.

Intervention: An initial bolus intravenous injection (67.5 U/kg body weight) over 10 minutes of AP or placebo, followed by continuous infusion (132.5 U/kg) over the following 23 hours and 50 minutes.

Measurements and Main Results: Median plasma creatinine levels declined significantly from 91 (73-138) to 70 (60-92) μmol/L only after AP treatment. Pathophysiology of nitric oxide (NO) production and subsequent renal damage were assessed in a subgroup of 15 patients. A 42-fold induction (vs. healthy subjects) in renal inducible NO synthase expression was reduced by 80% ± 5% after AP treatment. In AP-treated patients, the increase in cumulative urinary NO metabolite excretion was attenuated, whereas the opposite occurred after placebo. Reduced excretion of NO metabolites correlated with the proximal tubule injury marker glutathione S-transferase A1-1 in urine, which decreased by 70 (50-80)% in AP-treated patients compared with an increase by 200 (45-525)% in placebo-treated patients.

Conclusions: In severe sepsis and septic shock, infusion of AP inhibits the upregulation of renal inducible NO synthase, leading to subsequent reduced NO metabolite production, and attenuated tubular enzymuria. This mechanism may account for the observed improvement in renal function.

Critical Care Medicine:
February 2009 - Volume 37 - Issue 2 - pp 417-e1Heemskerk, Suzanne PhD; Masereeuw, Rosalinde PhD; Moesker, Olof; Bouw, Martijn P. W. J. M.; van der Hoeven, Johannes G. MD, PhD; Peters, Wilbert H. M. PhD; Russel, Frans G. M. PhD; Pickkers, Peter MD, PhD; on behalf of the APSEP Study Group

Effect of alendronate on bone mineral density and bone turnover markers in post-gastrectomy osteoporotic patients

noreply@blogger.com (Diagnostic Research) — Thu, 20 Aug 2009 15:46:00 +0000

Alendronate decreases the urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX; about 45% at 3 months) and serum levels of alkaline phosphatase (ALP; about 27% at 24 months), leading to an increase in lumbar spine bone mineral density (BMD; about 9% at 24 months) in postmenopausal Japanese women with osteoporosis. However, the effectiveness of oral bisphosphonates on osteoporosis remains to be established in patients who have undergone a gastrectomy. The objective of the present case series study was to examine the effect of alendronate on BMD and bone turnover markers in post-gastrectomy osteoporotic patients.

Sixteen patients (3 men and 13 postmenopausal women) with osteoporosis, who had undergone a gastrectomy (mean age: 69.1 years), were recruited in our outpatient clinic. All the patients were treated with alendronate (5 mg daily or 35 mg weekly) for 24 months. The effects of alendronate on lumbar spine (women) or total hip (men) BMD and urinary NTX and serum ALP levels were examined. A total or partial gastrectomy had been performed for eight patients each. The mean duration after surgery was 16.0 years. With alendronate therapy, urinary NTX levels significantly decreased at 3 months (-27.0%). Serum ALP levels decreased (-12.1%) and lumbar spine BMD increased (+5.2%), but total hip BMD did not significantly change (+0.6%) at 24 months. No severe adverse events were observed, and alendronate therapy was well tolerated. These results suggest that alendronate mildly increases lumbar spine BMD by mildly reducing bone turnover in osteoporotic patients after a gastrectomy.

Iwamoto J, Uzawa M, Sato Y, Takeda T, Matsumoto H.
Institute for Integrated Sports Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan

Intestinal alkaline phosphatase regulates protective surface microclimate pH

noreply@blogger.com (Diagnostic Research) — Wed, 20 May 2009 20:20:00 +0000

Keio U School of Medicine;

Regulation of localized extracellular pH (pHe) maintains normal organ function. An alkaline microclimate overlying the duodenal enterocyte brush border protects the mucosa from luminal acid. We hypothesized that intestinal alkaline phosphatase (IAP) regulates pHe due to pH-sensitive ATP hydrolysis as part of an ecto-purinergic pH regulatory system, comprised of cell-surface P2Y receptors and ATP-stimulated duodenal bicarbonate secretion (DBS). To test this hypothesis, we measured DBS in a perfused rat duodenal loop, examining the effect of the competitive alkaline phosphatase inhibitor glycerol phosphate (GP), the ecto-nucleoside triphosphate diphosphohydrolase inhibitor ARL67156, and exogenous nucleotides or P2 receptor agonists on DBS. Furthermore, we measured perfusate ATP concentration with a luciferin-luciferase bioassay. IAP inhibition increased DBS and luminal ATP output. Increased luminal ATP output was partially CFTR-dependent, but was not due to cellular injury. Immunofluorescence localized the P2Y1 receptor to the brush border membrane of duodenal villi. The P2Y1 agonist 2-methylthio-ADP increased DBS, whereas the P2Y1 antagonist MRS2179 reduced ATP- or GP-induced DBS. Acid perfusion augmented DBS and ATP release, further enhanced by the IAP inhibitor L-cysteine, and reduced by the exogenous ATPase apyrase. Furthermore, MRS2179 or the highly selective P2Y1 antagonist MRS2500 co-perfused with acid induced epithelial injury, suggesting that IAP/ATP/P2Y signalling protects the mucosa from acid injury. Increased DBS augments IAP activity presumably by raising pHe, increasing the rate of ATP degradation, decreasing ATP-mediated DBS, forming a negative feedback loop. The duodenal epithelial brush border IAP/P2Y/HCO3- surface microclimate pH regulatory system effectively protects the mucosa from acid injury.

Microfluidic immunosensor design for the quantification of interleukin-6 in human serum samples

noreply@blogger.com (Diagnostic Research) — Wed, 06 Aug 2008 14:42:00 +0000

Interleukin-6 (IL-6), an inflammatory cytokine, is one of the most important mediators of fever, the acute phase response, and inflammatory conditions. Described here is an integrated microfluidic immunosensor capable of detecting the concentration of IL-6 in human serum samples by use of an electrochemical method in a microfluidic biochip format. The detection of IL-6 was carried out using a sandwich immunoassay method based on the use of anti-IL-6 monoclonal antibodies, immobilized on a 3-aminopropyl-modified controlled-pore glass (APCPG) packet in a central channel (CC) of the microfluidic system. The IL-6 in the serum sample is allowed to react immunologically with the immobilized anti-IL-6 and biotin-labeled second antibodies specific to IL-6. After washing, the streptavidin–alkaline phosphatase conjugate is added. p-Aminophenyl phosphate is converted to p-aminophenol by alkaline phosphatase, and the electroactive product is quantified on a gold electrode at 0.10 V. For electrochemical detection and enzyme immunoassay, the LOD was 0.41 and 1.56 pg mL−1, respectively. Reproducibility assays employed repetitive standards of IL-6, and the intra- and inter-assay coefficients of variation were below 6.5%. Compared with the traditional IL-6 sensing method, the integrated microfluidic immunosensor required smaller amounts of sample to perform faster detection.

ARTICLE

Staphylococcal enterotoxin C injection in combination with ascorbic acid promotes the differentiation of bone marrow-derived mesenchymal stem cells...

noreply@blogger.com (Diagnostic Research) — Fri, 25 Jul 2008 14:13:00 +0000

Staphylococcal enterotoxin C injection is established as a clinical therapy for delayed healing or disunion of bone fractures. In the present study, the effects of staphylococcal enterotoxin C injection in combination with ascorbic acid (SEC-AA) on the differentiation of bone marrow-derived mesenchymal stem cells (MSCs) and their influences on the mineralization of osteoblasts were investigated. SEC-AA treatment induced increased levels of alkaline phosphatase activity in MSCs and increased numbers of alizarin red-stained calcified nodules, indicating enhanced differentiation of MSCs into osteoblasts. The findings demonstrated that SEC-AA promoted the differentiation of MSCs into osteoblasts and accelerated the cytopoiesis of osteoblasts. Our data provide a cytological model for bone fracture therapy aimed at shortening the time required for healing and improving the clinical outcome, and also provide a theoretical basis for inducible differentiation of MSCs, mineralization of osteoblasts and reconstruction of bone tissues.

ARTICLE

Liver function tests

noreply@blogger.com (Diagnostic Research) — Tue, 22 Jul 2008 20:36:00 +0000

Exam Overview
Some blood tests are used to determine whether your liver is damaged or inflamed. Although these tests help your doctor evaluate how well your liver is working, they cannot tell if you have hepatitis C.

Tests that assess liver function
Your doctor may do tests to measure certain chemicals produced by the liver. These tests can help your doctor check how well your liver is working. Tests may measure:

Bilirubin

Albumin

Prothrombin time (a measure of blood clotting). It may also be called International Normalized Ratio (INR).

Tests that check for inflammation of the liver (liver enzyme studies)
If you have increased levels of the following, your liver may be damaged:

Alanine aminotransferase (ALT or SGPT)

Aspartate aminotransferase (AST or SGOT)

An increased level of alkaline phosphatase (AP) may indicate blockage of bile ducts.

Why It Is Done
Liver tests are done when a medical history or physical exam suggests that something may be wrong with your liver.

These tests can also help diagnose long-term (chronic) infection. Hepatitis C infection is considered chronic when liver enzymes remain elevated for longer than 6 months.

If you are being treated with antiviral therapy, you may have liver tests from time to time to see whether treatment is working.

Results
Findings of liver function tests may include the following:

Normal
All levels are within the normal range.

Abnormal
One or more levels are outside the normal range. Abnormal liver function tests may indicate that your liver is inflamed or is not working normally. This can be a sign that you have a viral infection.

What To Think About
Elevated liver enzymes can be caused by many things other than hepatitis C, such as obesity, hepatitis B, autoimmune hepatitis, certain medicines, or long-term alcohol use. So you will need other tests (such as a hepatitis C antibody blood test or a liver biopsy) to confirm a diagnosis of hepatitis C.

People with chronic hepatitis C have abnormal liver enzyme levels most of the time. But the levels can fluctuate between normal and abnormal throughout the course of the disease.

Liver tests can be used to help you and your doctor develop a treatment plan. Signs that you might need treatment include:

Liver enzyme levels that remain above normal for longer than 6 months, which is evidence of chronic infection.
Detectable levels of hepatitis C virus in your blood (positive hepatitis C RNA test). This is a sign of an active infection.
Evidence of serious liver damage. This is detected with a liver biopsy.

Alkaline Phosphatase-positive Colony Formation is a Sensitive, Specific and Quantitative Indicator of Undifferentiated Human Embryonic Stem Cells

noreply@blogger.com (Diagnostic Research) — Mon, 21 Jul 2008 19:02:00 +0000

Human embryonic stem cells (hESCs) can be maintained in vitro as immortal pluripotent cells but remain responsive to many differentiation-inducing signals. Investigation of the initial critical events involved in differentiation induction would be greatly facilitated if a specific, robust and quantitative assay for pluripotent hESCs with self-renewal potential were available. Here we describe the results of a series of experiments to determine whether the formation of adherent alkaline phosphatase-positive (AP+) colonies under conditions optimized for propagating undifferentiated hESCs would meet this need. The findings can be summarized as follows: (1) Most colonies obtained under these conditions consist of 30 AP+ cells that co-express OCT4, NANOG, SSEA3, SSEA4, TRA-1-60 and TRA-1-81. (2) Most such colonies are derived from SSEA3+ cells. (3) Primary colonies contain cells that produce secondary colonies of the same composition, including cells that initiate multi-lineage differentiation in embryoid bodies (EBs). (4) Colony formation is independent of plating density or the colony-forming cell (CFC) content of the test population over a wide range of cell concentrations. (5) CFC frequencies decrease when differentiation is induced, either by exposure to retinoic acid or to conditions that stimulate EB formation. Interestingly, this loss of AP+ clonogenic potential also occurs more rapidly than the loss of SSEA3 or OCT4 expression. The CFC assay thus provides a simple, reliable, broadly applicable and highly specific functional assay for quantifying undifferentiated hESCs with self-renewal potential. Its use under standardized assay conditions should enhance future elucidation of the mechanisms that regulate hESC propagation and their early differentiation.

Biofunctionalization of aqueous dispersed, alumina membrane-templated polymer nanorods for use in enzymatic chemiluminescence assays

noreply@blogger.com (Diagnostic Research) — Thu, 17 Jul 2008 15:00:00 +0000

The noncovalent immobilization of alkaline phosphatase (ALP) onto aqueous dispersed nylon 6 nanorods (310 nm mean diameter; 6 μm mean length) prepared by anodic aluminum oxide (AAO) membrane templating was studied. Using multi-stacked layer-by-layer (LBL) assembly with the cationic quaternary ammonium polymer Sapphire II™, the amount of alkaline phosphatase (ALP) enzyme loaded onto the polymer nanostructures was found to be 115 ± 7 μg mg−1 nanorod. The biofunctionalized nanorods were also characterized for their chemiluminescent activity with the dioxetane substrate, CSPD™. The results indicate that the kinetic parameters, Km and Vmax, for the catalytic activity of the nanostructure-bound alkaline phosphatase (ALP) enzyme are different from those of soluble (‘free’) ALP. While the Km value was measured to be 156 μM for free ALP, the apparent Km value determined for the LBL-immobilized ALP is approximately 20% lower (122 μM). Furthermore, despite the relatively high enzyme loading capacity of the nanorods, the specific activity of the bound ALP enzyme was found to be almost nine times lower than that measured for free ALP. Finally, additional experiments revealed that the catalytic activities of both free ALP and nanorod-conjugated ALP are affected similarly by changes in pH, with optimal performance levels occurring under conditions of pH 9.5. To the best of our knowledge, this study represents the first report examining the preparation of aqueous dispersed, AAO-templated polymer nanorods for potential application as enzyme scaffolds in chemiluminescent-based assay systems.

ARTICLE

An in vivo murine model of continuous intramedullary infusion of polyethylene particles

noreply@blogger.com (Diagnostic Research) — Thu, 17 Jul 2008 14:58:00 +0000

Wear debris affects both initial osseointegration and subsequent bone remodeling of total joint replacements (TJRs). To study the complex cascade associated with the continuous generation of particles, a robust animal model is essential. To date, an animal model that incorporates continuously delivered particles to an intramedullary orthopaedic implant has not been available. In this study, we successfully infused clinically relevant ultra high molecular weight polyethylene particles, previously isolated from joint simulator tests, to the intramedullary space of the mouse femur for 4 weeks using a subcutaneous osmotic pump. Reduction of bone volume following the 4-week infusion of UHMWPE was detected by microCT. UHMWPE particles also changed the level of Alkaline Phosphatase expression in the infused femurs. Continuous infusion of particles to the murine bone–implant interface simulated the clinical scenario of local polymer wear particle generation and delivery in humans and can be used to further study the biological processes associated with wear debris particles.

ARTICLE

Cultured stem cells are sensitive to gravity changes

noreply@blogger.com (Diagnostic Research) — Thu, 17 Jul 2008 14:55:00 +0000

Stem and precursor cells play an important role in development and regeneration. The state of these cells is regulated by biochemical substances, mechanical stimuli and cellular interactions. To estimate gravity effects we used two types of cultured stem cells: human mesenchymal stromal cells (hMSCs) from bone marrow and mice embryonic stem (mESC) line R1. Gravity changes were simulated by long-term (4–7 days) slow clinorotation and leaded to decreased hMSC proliferation, changes of cell morphology and modified F-actin cytoskeleton. We did not find the shifts in cell phenotype except for decreased expression of HLA 1 and CD105 but excretion of IL-6 into medium increased significantly. Remodeling of cytoskeleton started after first 4 h and was similar to preapoptotic changes. This data suggested the modification in cell adhesion and possible commitment of hMSC. It was observed that expression of alkaline phosphatase by MSC in osteogenic medium was more intensive in control. On the contrary, clinorotation did not change formation of mESC colonies and increased proliferation activity in LIF+-medium. However, the number of embryonic bodies after clinorotation was less than in static control. It is suggested that ESCs kept the viability and proliferative potential but decreased the differentiation ability after changes in gravity stimulation.

ARTICLE

Alkaline phosphatase conductometric biosensor for heavy-metal ions determination

noreply@blogger.com (Diagnostic Research) — Tue, 01 Jul 2008 20:25:00 +0000

Alkaline phosphatase conductometric biosensors consisting of interdigitated gold electrodes and enzyme membranes have been used for assessment of heavy-metal ions in water. These analytes act as enzyme inhibitors. Enzyme residual activity has been measured in Tris-nitrate buffer without metal preincubation in the presence of Mg2+ ions as activator. The results indicate that the toxicity of the various metals tested toward immobilized phosphatase is ranged as follows: Cd2+ > Co2+ > Zn2+ > Ni2+ > Pb2+. Detection limits were about 0.5 ppm for Cd2+, 2 ppm for both Zn2+ and Co2+, 5 ppm for Ni2+ and 40 ppm for lead ions. In addition, the responses during 10 h were stable (RSD 4%) and a drift of about 7% per day was observed. The storage stability in buffer solution at 4 °C remained stable for more than one month.

ARTICLE

Investigation of the enzyme hydrolysis products of the substrates of alkaline phosphatase in electrochemical immunosensing

noreply@blogger.com (Diagnostic Research) — Fri, 13 Jun 2008 15:55:00 +0000

Abstract
In this paper, we have critically evaluated the electrochemical behavior of the products of seven substrates of the enzyme label, alkaline phosphate, commonly used in electrochemical immunosensors. These products (and the corresponding substrates) include indigo carmine (3-indoyl phosphate), hydroquinone (hydroquinone diphosphate), 4-nitrophenol (4-nitrophenol phosphate), 4-aminophenol (p-aminophenyl phosphate), 1-naphthol (1-naphthyl phosphate), phenol (phenyl phosphate), and l-ascorbic acid (2-phospho-l-ascorbic acid). Cyclic voltammetry and amperometry of these products were carried out at glassy carbon (GC), screen-printed carbon (SPC) and gold (Au) electrodes, respectively. Among the products, l-ascorbic acid showed the most sensitive (24.8 μA cm−2, 12.0 μA cm−2, and 48.0 μA cm−2 of 100 μM ascorbic acid at GC, SPC, and Au electrodes, respectively) and well-defined amperometric response at all electrodes used, making 2-phospho-l-ascorbic acid the best substrate in electrochemical detection involving an alkaline phosphate, enzyme label. The 2-phospho-l-ascorbic acid is also commercially available and inexpensive. Therefore, it was the best choice for electrochemical detection using ALP as label. Using mouse IgG as a model, an ALP enzyme-amplified sandwich-type amperometric immunosensor was constructed. The immunosensor was designed by electropolymerization of o-aminobenzoic acid (o-ABA) conductive polymer on the surface of GC, SPC, and Au electrodes. The anti-mouse IgG was subsequently attached on the electrode surface through covalent bonding between IgG antibody and the carboxyl groups from poly(o-ABA). Using 2-phospho-l-ascorbic acid as a substrate, the poly(o-ABA)/Au immunosensor produced the best signal (about 297 times of current density response ratio between 1000 ng mL−1 and 0 ng mL−1 of mouse IgG), demonstrating that amperometric immunosensors based on a conducting polymer electrode system were sensitive to concentrations of the mouse IgG down to 1 ng mL−1, with a linear range of 3–200 ng mL−1 (S.D. < 2; n = 3), and very low non-specific adsorption.

Anchana Preechaworapuna, b, Zong Daia, Yun Xianga, Orawon Chailapakulb, , and Joseph Wang

ARTICLE

CA15-3 and alkaline phosphatase as predictors for breast cancer recurrence: a combined analysis of seven International Breast Cancer Study Group trial

noreply@blogger.com (Diagnostic Research) — Fri, 08 Feb 2008 21:17:00 +0000

Background: We evaluated the ability of CA15-3 (cancer antigen 15-3) and alkaline phosphatase (ALP) to predict breast cancer recurrence.

Patients and methods: Data from seven International Breast Cancer Study Group trials were combined. The primary end point was relapse-free survival (RFS) (time from randomization to first breast cancer recurrence), and analyses included 3953 patients with one or more CA15-3 and ALP measurement during their RFS period. CA15-3 was considered abnormal if >30 U/ml or >50% higher than the first value recorded; ALP was recorded as normal, abnormal, or equivocal. Cox proportional hazards models with a time-varying indicator for abnormal CA15-3 and/or ALP were utilized.

Results: Overall, 784 patients (20%) had a recurrence, before which 274 (35%) had one or more abnormal CA15-3 and 35 (4%) had one or more abnormal ALP. Risk of recurrence increased by 30% for patients with abnormal CA15-3 [hazard ratio (HR) = 1.30; P = 0.0005], and by 4% for those with abnormal ALP (HR = 1.04; P = 0.82). Recurrence risk was greatest for patients with either (HR = 2.40; P < 0.0001) and with both (HR = 4.69; P < 0.0001) biomarkers abnormal. ALP better predicted liver recurrence.

Conclusions: CA15-3 was better able to predict breast cancer recurrence than ALP , but use of both biomarkers together provided a better early indicator of recurrence. Whether routine use of these biomarkers improves overall survival remains an open question.

Annals of Oncology Advance Access originally published online on January 20, 2007 .Annals of Oncology 2007 18(4):701-708; doi:10.1093/annonc/mdl492

Prediction of Survival of Metastatic Prostate Cancer Based on Early Serial Measurements of Prostate Specific Antigen and Alkaline Phosphatase

noreply@blogger.com (Diagnostic Research) — Mon, 26 Nov 2007 23:22:00 +0000

Purpose
We determined how serial measurements of prostate specific antigen and alkaline phosphatase can be used to predict survival early in the course of hormone treated metastatic prostate cancer.

Materials and Methods
The study was based on a prospective randomized trial of 915 patients with metastatic prostate carcinoma designed to compare parenteral estrogen (polyestradiol phosphate) vs total androgen blockade. We included 697 men who survived at least 6 months and had complete serial measurements of prostate specific antigen and alkaline phosphatase . Six models were constructed based on prostate specific antigen and alkaline phosphatase at start, and after 6 months of treatment, alkaline phosphatase flare and relative prostate specific antigen velocity. We constructed time dependent receiver operating characteristic curves with corresponding area under the curve to predict death from prostate cancer within 3 years.

Results
The best variables to predict outcome were alkaline phosphatase at 6 months (AUC 0.79 for polyestradiol phosphate and 0.72 for total androgen blockade), alkaline phosphatase at baseline (AUC 0.70 for polyestradiol phosphate and total androgen blockade) and prostate specific antigen at 6 months (AUC 0.70 for polyestradiol phosphate and total androgen blockade). Prostate specific antigen and alkaline phosphatase levels 6 months after start of treatment give better prediction of survival than baseline levels.

Conclusions
Alkaline phosphatase at start of treatment and alkaline phosphatase and prostate specific antigen after 6 months can be used to predict survival of hormone treated metastatic prostate cancer.
Department of Urology, Ryhov County Hospital, 55185 Jönköping, Sweden
doi:10.1016/j.juro.2007.08.132
The Journal of Urology

Alkaline Phosphatase

noreply@blogger.com (Diagnostic Research) — Wed, 31 Oct 2007 20:12:00 +0000

Alkaline phosphatase (ALP) (EC 3.1.3.1) is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides , proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation. As the name suggests, alkaline phosphatase's are most effective in an alkaline environment.

The follwing is from labtest online: When a person has evidence of liver disease , very high ALP levels can tell the doctor that the person’s bile ducts are somehow blocked. Often, ALP is high in persons who have cancer that has spread to the liver or the bones, and doctors can do further testing to see if this has happened. If a person with bone or liver cancer responds to treatment, ALP levels will decrease. When a person has high levels of alkaline phosphatase, and the doctor is not sure why, s/he may also order alkaline phosphatase isoenzyme tests to try to determine the cause.

Accoring to Labone, Alkaline Phosphatase is generally part of a routine lab testing profile, often with a group of other tests called a liver panel. Alkaline phosphatase is also usually ordered along with several other tests if a patient seems to have symptoms of a liver or bone disorder.

High Alkaline Phosphatase usually means that the bone or liver has been damaged. If other liver tests such as bilirubin , aspartate aminotransferase (AST), or alanine aminotransferase (ALT) are also high, usually the ALP is coming from the liver. If calcium and phosphate measurements are abnormal, usually the ALP is coming from bone.

In some forms of liver disease, such as hepatitis, alkaline Phosphatase is usually much less elevated than AST and ALT. When the bile ducts are blocked (usually by gallstones, scars from previous gallstones or surgery, or by cancers), ALP and bilirubin may be increased much more than Aspartate aminotransferaseAST or Alanine transaminaseALT. In a few liver diseases, ALP may be the only test that is high.

In some bone diseases, such as a disorder called Paget’s disease(where bones become enlarged and deformed), or in certain cancers that spread to bone, ALP may be the only test result that is high.

Sometimes doctors don’t know why alkaline phosphatase is high, and they need to order other tests to determine the exact cause. In such cases, your doctor may order another enzyme, gamma glutamyl transpeptidase gGT, that is made by the liver in the same places as is ALP, but which is not made by bone.