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PubMed1985

Synthetic and natural Escherichia coli free lipid A express identical endotoxic activities.

The recently chemically synthesized Escherichia coli lipid A and the natural free lipid A of E. coli were compared with respect to their endotoxic activities in the following test systems: lethal toxicity, pyrogenicity, local Shwartzman reactivity, Limulus amoebocyte lysate gelation capacity, tumour necrotizing activity, B cell mitogenicity, induction of prostaglandin synthesis in macrophages, and antigenic specificity. It was found that synthetic and natural free lipid A exhibit identical activities and are indistinguishable in all tests.

Animals↗
PubMed2004

Helicobacter pylori lipopolysaccharide: biological activities in vitro and in vivo, pathological correlation to human chronic gastritis and peptic ulcer.

AIM: To determine the biological activity of Helicobacter pylori (H. pylori) lipopolysaccharide (H-LPS) and understand pathological correlation between H-LPS and human chronic gastritis and peptic ulcer. METHODS: H-LPS of a clinical H. pylori strain and LPS of Escherichia coli strain O55:B5 (E-LPS) were extracted by phenol-water method. Biological activities of H-LPS and E-LPS were detected by limulus lysate assay, pyrogen assay, blood pressure test and PBMC induction test in rabbits, cytotoxicity test in NIH 3T3 fibroblast cells and lethality test in NIH mice. By using self-prepared rabbit anti-H-LPS serum as the first antibody and commercial HRP-labeled sheep anti-rabbit sera as the second antibody, H-LPS in biopsy specimens from 126 patients with chronic gastritis (68 cases) or gastric ulcer (58 cases) were examined by immunohistochemistry. RESULTS: Fibroblast cytotoxicity and mouse lethality of H-LPS were weaker than those of E-LPS. But the ability of coagulating limulus lysate of the two LPSs was similar (+/0.5 ng/mL). At 0.5 h after H-LPS injection, the blood pressures of the 3 rabbits rapidly declined. At 1.0 h after H-LPS injection, the blood pressures in 2 of the 3 rabbits fell to zero causing death of the 2 animals. For the other one rabbit in the same group, its blood pressure gradually elevated. At 0.5 h after E-LPS injection, the blood pressures of the three rabbits also quickly declined and then maintained at low level for approximately 1.0 h. At 0.5 h after injection with H-LPS or E-LPS, PBMC numbers of the rabbits showed a remarkable increase. The total positivity rate of H-LPS from 126 biopsy specimens was 60.3%(76/126). H-LPS positivity rate in the biopsy specimens from chronic gastritis (50/68, 73.5%) was significantly higher than that from gastric ulcer (26/58, 44.8%) (chi(2)=10.77, P<0.01). H-LPS positivity rates in biopsy specimens from chronic superficial gastritis (38/48, 79.2%) and chronic active gastritis (9/10, 90.0%) were significantly higher than that of the patients with atrophic gastritis (3/10, 30.0%) (chi(2)=7.50-9.66, P<0.01). CONCLUSION: The biological activities of H-LPS were weaker than those of E-LPS, the activities of H-LPS of lowering rabbit blood pressure and inducing rabbit PBMC were relatively stronger. H-LPS may play a critical role in inducing inflammatory reaction in human gastritis.

3T3 Cells↗
PubMed1994

Endotoxin contamination causes neutrophilia following pulmonary allergen challenge.

Segmental bronchoprovocation (SBP) with allergen was used in an attempt to study eosinophils recruited to the airway 24 h after challenge. Unexpectedly, in the first four patients, neutrophils (rather than eosinophils) were recruited in the bronchoalveolar lavage (BAL) fluids, and we hypothesized that the allergen extracts were contaminated with endotoxin. The extracts used for challenge in the first four patients tested positive for bacterial endotoxin in a limulus amebocyte lysate assay. Rechallenge of one patient from the first group with a comparable dose of an endotoxin-free extract and SBP with endotoxin-free extract in five additional patients resulted in preferential recruitment of eosinophils rather than neutrophils. The number of neutrophils recovered from the challenged segments in the patients challenged with endotoxin-free extract was significantly less than that observed in the first four patients. Taken together, these observations suggest that neutrophil recruitment in the 24-h BAL fluids from the first four patients was probably due to endotoxin contamination of the allergen extract. We caution investigators that endotoxin contamination of allergen extract may alter the cellular inflammation during the late airway response following allergen challenge.

Adolescent↗
PubMed2005

Development of an approach for the laboratory toxicological evaluation of Bordetella pertussis adenylate cyclase genetic toxoid constructs as multipurpose vaccines.

Detoxified recombinant CyaA constructs have been developed as potential viral and tumoral epitope carriers for immunoprophylactic and therapeutic vaccination and as antigen candidates for inclusion in acellular pertussis vaccines. In this work, we attempt to explore a test system for the laboratory safety evaluation of CyaA preparations. Endotoxin was determined in vitro by the Limulus amoebocyte lysate assay. Cytotoxicity was measured by a tetrazolium salt test and a lactate dehydrogenase release assay using murine and human phagocytic cell lines. Cell viability was < 50% at concentrations > 1 microg/mL of the wild type toxin and concentrations in the nanogram range inhibited the zymosan-induced oxidative burst as measured by chemiluminescence. However, no effects were observed for detoxified and non-acylated forms of CyaA at comparable and higher toxin concentrations. Effects found in the in vitro assays could not be related to the in vivo mouse weight gain test used as a general toxicity test. In vitro cytotoxicity and oxidative burst studies on phagocytes, and the evaluation of endotoxin levels are useful for safety screening of CyaA constructs. However, in vivo specific toxicity tests and potential toxic implications of enzymatic activity-independent effects of CyaA on cell function should be investigated.

Acridines↗
PubMed1984

Biological activities of analogues of lipid A based chemically on the revised structural model. Comparison of mediator-inducing, immunomodulating and endotoxic activities.

Lipid A analogues were chemically synthesized based on the model structure recently revised, and biological activities of the analogues were tested. The analogue, (beta-1,6)-linked glucosamine disaccharide carrying ester-bound 3-hydroxytetradecanoic acids at 3 and 3' position of reducing and nonreducing glucosamine in addition to amide-bound 3-hydroxytetradecanoic acids and glycosidic-linked and ester-linked phosphate groups, showed much stronger activities for mediator inducing and immunomodulating as well as endotoxic activities than those exhibited by the previously synthesized analogues based on the old model. Among the activities tested, induction of interferon and tumor necrosis factor as well as mitogenicity, adjuvanticity and pyrogenicity were, however, not expressed so strongly as natural lipid A used as controls. In contrast, the analogue exhibited comparable activities to those of control lipid A in the test of lethal toxicity to mice and gelating activity of Limulus amebocyte lysate. Other synthetic analogues carrying a phosphate group showed comparable, slightly stronger or weaker activities depending on the test, but nonphosphorylated analogue exhibited no apparent or only very weak activities.

Adjuvants, Immunologic↗
PubMed1981

Reactivity of the limulus lysate assay with uterine cervical secretions. A preliminary evaluation.

A limulus lysate assay was performed on cervical secretions from 66 women. When secretions were tested at a 1/100 dilution the assay gave a positive result in 15 (62.5%) of 24 patients with gonorrhoea confirmed by Gram-stained smear or culture or both. When secretions from seven of the nine remaining patients who had gonorrhoea but negative results to the limulus lysate test were retested at 1/50 dilution, two gave a positive result, increasing the positivity rate of the test to 17 (70.8%) of 24 infected patients. Material from one patient with a history of contact with gonorrhoea and from three (7.3%) of the other 41 patients without any history of gonorrhoea gave positive reactions.

Cervix Mucus↗
PubMed1988

Detection of endotoxin in cases of equine colic.

The Limulus amoebocyte lysate assay was used to test for the presence of endotoxin in 37 clinical cases of equine colic. Positive plasma titres were detected in 10 cases and the presence of endotoxin was significantly correlated with a high heart rate, a high packed cell volume and a poor prognosis. High levels of endotoxin were detected in gut contents taken from several sites in the gastrointestinal tract of normal horses.

Animals↗
PubMed1999

New Applications of the Human Whole Blood Pyrogen Assay (PyroCheck).

The absence of pyrogens in injectable drugs is an indispensable safety control because contaminants causing fever pose a life-threatening risk to the patient resulting in the worst case in death by shock. When fever- inducing agents, i.e.pyrogens, come into contact with the immunocompetent cells in blood, these cells release mediators which transmit the fever signal to the thermoregulatory centre of the brain. The Phamocopoeia lists currently two test systems for pyrogenicity: 1. The in vivo rabbit pyrogen test which measures the fever reaction following injection of the sample to the animals. 2. The in vitro Limulus Amebocyte Lysate assay (LAL) which measures the coagulation in a lysate prepared from the blood of the horseshoe crab specifically initiated by endotoxins, i.e. cell wall components from Gram-negative bacteria. The new test presented here (PyroCheck) exploits the reaction of monocytes/macrophages for the detection of pyrogens: human whole blood taken from healthy volunteers is incubated in the presence of the test sample in any form, be it a solution, a powder or even solid material. Pyrogenic contaminations initiate the release of the "endogenous pyrogen" Interleukin-1beta determined by ELISA after a fixed incubation time. The technology presently listed in the Pharmacopoeia is limited to parenteralia (rabbit test: biologicals and pharmaceuticals, LAL: predominantly pharmaceuticals). In the EU Medical Devices Directive from 1995 the rabbit pyrogen test for medical products is in some cases requested. (in some cases LAL of an eluate from the device). However, pyrogen-testing needs to cover also innovative high-tech products such as medical devices (implants, medical plastic materials, dialysis machines), cellular therapies and species-specific agents (e.g. recombinant proteins). Here we report that the human blood test PyroCheck is suitable for testing filters in air quality control as well as for assessing medical devices and biocompatibility (dialysate fluid), i.e. that it can be extended to a wide spectrum of applications.

Pyrogens↗
PubMedDate not supplied

Evaluation of the endotoxin retention capabilities of inline intravenous filters.

The capabilities of inline filters to retain bacteria and endotoxin were examined during simulated extended infusions for up to 168 hr. The tested inline filters were the ELD96 (Pall Biomedical Corp) and the IVEX 2 (Millipore Corp). Approximately 1 x 10(8) total cells of Escherichia coli B. were challenged to the upstream site of the filter. The test solution of 5% dextrose in water, 0.9% saline, Paremental A (A basic solution for total parenteral nutrition (TPN), a TPN solution in use in our clinic were infused continuously up to 168 hr and flow rate was maintained at 83 ml/hr. The effluents were analyzed using the Limulus Amebocyte Lysate (LAL) test to detect endotoxin and also passage of the challenged bacteria was tested at 24-hr intervals over 168 hr. The results were as follows: (1) The viability control culture showed the presence of viable bacteria throughout the 168-hr period of the experiment. (2) During the experiments, all filters produced sterile effluents. (3) LAL assay indicated that only the effluents from the ELD96 contained no detectable endotoxin for 168 hr.

Catheterization, Central Venous↗
PubMed1993

Extracorporeal endotoxin removal by immobilized polyethylenimine.

The neutralization of bacterial endotoxins (ET) is still an unsolved problem in therapeutic medicine. The efficacy of anti-endotoxin antibodies or receptor antagonists and other substances interfering with the endotoxin-induced pathomechanisms is dependent on an intact cellular degradation system of the host. However, the phagocytosis function of that system seems to be impaired regularly in patients with intense or long-lasting endotoxemia or septic shock and in patients undergoing hemodialysis. Extracorporeal adsorption of ET might well be an effective support in the anti-ET therapy by lowering the amount of circulating ET and thus relieving the defense system of the body. In this work a new ET-adsorbent based on macroporous cellulosic beads with immobilized polyethylenimine (PEI) was tested for its ET-removal capacity in vitro. A test solution with 100 ng/ml ET from Escherichia coli 055:B5 was recirculated in a system containing the adsorbent beads. Polymyxin B immobilized to the same carrier was used for comparison. PEI as well as polymyxin B showed complete removal of ET from plasma and water as was measured by the Limulus Amebocyte Lysate (LAL) test (Chromogenix). The biocompatibility of the PEI absorber was superior to that of polymyxin B. The results indicate that the PEI absorber is of high efficacy and possibly of interest for the treatment of endotoxemia.

Adsorption↗
PubMed1982

Biological activity, lipoprotein-binding behavior, and in vivo disposition of extracted and native forms of Salmonella typhimurium lipopolysaccharides.

Although phenol-extracted gram-negative bacterial lipopolysaccharides (LPS) have been used to study the properties of endotoxins for many years, nothing is known about the behavior of native (unextracted) LPS in vivo. Accordingly, we have compared extracted and native forms of LPS with regard to their biological activity, their ability to bind to plasma high density lipoproteins (HDL), and their fate after intravenous injection into rats. The LPS of Salmonella typhimurium G-30 were labeled with [(3)H]galactose, and whole bacteria, bacterial outer membranes, outer membrane fragments (harvested from the bacterial culture supernatant), and phenol extracts of the bacteria were prepared. After defining the LPS, phospholipid, and protein composition of these preparations, we compared the activity of the LPS in phenol extracts and membrane fragments in two assays. In both the limulus lysate assay and the rabbit pyrogen test, the LPS in phenol extracts were slightly more potent than the LPS in membrane fragments. We next studied the ability of the LPS in each preparation to bind to rat lipoproteins in vitro, and each preparation was then injected intravenously into rats for measurements of LPS-HDL binding and tissue uptake in vivo. Two patterns of lipoprotein binding were observed. Less than 25% of the LPS in both outer membranes and whole bacteria bound to HDL in vitro. When the outer membranes and whole bacteria were injected into rats, their LPS again bound poorly to HDL and they were rapidly removed from plasma into the liver and spleen. In contrast, >50% of the LPS in both culture supernatant membrane fragments and phenol-water extracts bound to HDL in vitro. When these preparations were injected into rats, approximately 50% of the LPS in the membrane fragments and phenol-water extracts bound to HDL and remained in the plasma over the 10-min study period. Moreover, the LPS in these preparations accumulated in the ovary and the adrenal gland, two tissues that use HDL-cholesterol for hormone synthesis. Binding to HDL thus greatly influenced the plasma half-life and tissue uptake of both extracted and native LPS. We conclude that extraction of S. typhimurium LPS with phenol does not significantly alter the biological activity or the lipoprotein binding behavior of the LPS and that the in vivo fates of phenol-extracted and membrane fragment LPS are essentially identical. The results thus provide important support for many previous studies that have used phenol-extracted LPS to mimic the activities of native LPS in vivo. However, the only native LPS that resembled the behavior of extracted LPS were the LPS that had been shed from the bacteria in fragments of membrane that had reduced amounts of protein and phospholipid. Removal of LPS from other outer membrane constituents, whether by chemical extraction or by a natural process of surface shedding, thus alters the behavior of the LPS; the most important feature of this alteration appears to be the ability of these LPS to bind readily to HDL.

Adrenal Glands↗
PubMed2003

Stability and microbiology of inhalant N-acetylcysteine used as an intravenous solution for the treatment of acetaminophen poisoning.

STUDY OBJECTIVE: Intravenous N-acetylcysteine has been used as an antidote for acetaminophen poisoning for more than 25 years in Europe and Canada. In the United States, only the oral administration of N-acetylcysteine is approved by the US Food and Drug Administration. Many physicians routinely use the inhalant preparation as an intravenous formulation; however, no stability, microbiology, or pyrogen studies have been performed. In this study, we evaluate the stability and microbiology of inhalational N-acetylcysteine compounded as an intravenous formulation. METHODS: A total of 8 N-acetylcysteine solutions (solution A through H) were prepared by injecting 150 mL of 20% solution through a 22-microm filter to 1 L of 5% dextrose (D(5)W; 2.6% solution). Solutions A through C were prepared at ambient conditions (25 degrees C [77 degrees F], 65% relative humidity), and solution D was prepared at accelerated conditions (40 degrees C [104 degrees F], 75% relative humidity) for stability testing. The assays were performed by means of high-performance liquid chromatography at 0, 4, 8, 12, 24, 36, 48, 60, and 72 hours according to US Pharmacopeia XXIV methodology. Solutions E through G were assessed for bacterial growth, and solution H underwent pyrogen testing by using a Limulus amebocyte lysate method. RESULTS: Solutions A through C remained stable for at least 60 hours (<10% decomposition), but at 72 hours, there was a 10.3%, 14.9%, and 13.4% degradation, respectively. Under accelerated conditions (solution D), stability lasted for more than 72 hours. Solutions E through G remained free from bacterial growth at 72 hours, and solution H tested negative for endotoxins-pyrogens. CONCLUSION: Inhalational N-acetylcysteine prepared as an intravenous solution meets US Pharmacopeia standards for stability up to 60 hours and is free from bacteria and their byproducts, offering a viable alternative to the traditional use of oral N-acetylcysteine.

Acetaminophen↗
PubMed2001

The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor alpha in the pathogenesis of non-alcoholic steatohepatitis.

BACKGROUND: Small intestinal bacterial overgrowth may contribute to the development of non-alcoholic steatohepatitis, perhaps by increasing intestinal permeability and promoting the absorption of endotoxin or other enteric bacterial products. AIMS: To investigate the prevalence of small intestinal bacterial overgrowth, increased intestinal permeability, elevated endotoxin, and tumour necrosis factor alpha (TNF-alpha) levels in patients with non-alcoholic steatohepatitis and in control subjects. PATIENTS AND METHODS: Twenty two patients with non-alcoholic steatohepatitis and 23 control subjects were studied. Small intestinal bacterial overgrowth was assessed by a combined (14)C-D-xylose and lactulose breath test. Intestinal permeability was assessed by a dual lactulose-rhamnose sugar test. Serum endotoxin levels were determined using the limulus amoebocyte lysate assay and TNF-alpha levels using an ELISA. RESULTS: Small intestinal bacterial overgrowth was present in 50% of patients with non-alcoholic steatosis and 22% of control subjects (p=0.048). Mean TNF-alpha levels in non-alcoholic steatohepatitis patients and control subjects were 14.2 and 7.5 pg/ml, respectively (p=0.001). Intestinal permeability and serum endotoxin levels were similar in the two groups. CONCLUSIONS: Patients with non-alcoholic steatohepatitis have a higher prevalence of small intestinal bacterial overgrowth, as assessed by the (14)C-D-xylose-lactulose breath test, and higher TNF-alpha levels in comparison with control subjects. This is not accompanied by increased intestinal permeability or elevated endotoxin levels.

Adult↗
PubMed1997

Mouse in vitro fertilization, embryo development and viability, and human sperm motility in substances used for human sperm preparation for assisted reproduction.

OBJECTIVE: To investigate the endotoxin content and effects on mouse IVF and embryo development and human sperm motility of human sperm separation substances. DESIGN: One-cell and zona-free two-cell mouse embryo bioassays and Limulus Amoebocyte Lysate endotoxin tests and mouse oocyte parthenogenetic activation, IVF, preimplantation and postimplantation embryo development, and human sperm motility were performed in control medium or medium containing Percoll, Nicodenz, or the washings from Sperm Prep sephadex columns. SETTING: Research Laboratories, Sinai Hospital of Baltimore, Baltimore, Maryland. MAIN OUTCOME MEASURE(S): Endotoxin levels, embryo development, and sperm motility. RESULT(S): Mouse embryo bioassays indicated negative endotoxin levels in Percoll and Nicodenz but Limulus Amoebocyte Lysate assays had positive gel formation. Mouse IVF and preimplantation development was equivalent in control and Percoll- and Nicodenz-containing medium; none had parthenogenetic properties but postimplantation development was reduced for embryos grown in the presence of Percoll or Nicodenz. Human sperm remained motile in the presence of Percoll or Nicodenz. Sperm Prep column washes were toxic to mouse gametes and embryos and human sperm and had gel formation with the Limulus Amoebocyte Lysate assay. CONCLUSION(S): Percoll and Nicodenz, but not Sperm Prep sephadex column washes, were compatible with mouse preimplantation and postimplantation embryo development and human sperm motility.

Animals↗
PubMed2004

A synthetic peptide derived from bactericidal/permeability-increasing protein neutralizes endotoxin in vitro and in vivo.

Lipopolysaccharide (LPS [endotoxin]), a structural component of gram-negative bacteria, is implicated in the pathogenesis of septic shock. Lipid A is an evolutionarily conserved region of LPS that has been identified as the toxic component of LPS. Therapeutic strategies for the treatment of septic shock in humans are currently focused on neutralization of LPS. Here, the anti-endotoxin activity of BNEP, a synthetic peptide derived from the human bactericidal/permeability-increasing protein (BPI; aa 148-161) was investigated in vitro and in experimental animal endotoxemia models in vivo. The ability of BNEP to bind LPS from Escherichia coli O55:B5 and lipid A from Salmonella Re 595 was tested using an affinity sensor assay, and its ability to neutralize LPS was tested using a sensitive Limulus amebocyte lysate (LAL) assay. Polymyxin B (PMB) was used as the positive control in the in vitro experiments and in mouse experiments. We found that BNEP and PMB bound LPS with a similar affinity (Kd values of 25.4 and 25.8 nM, respectively). In contrast, BNEP bound lipid A with a slightly lower affinity than that of PMB (Kd values of 8 and 5.6 nM, respectively). The exact capacity of BNEP binding to LPS was approximately 0.53 microg peptide per 1 ng of LPS, as shown by affinity sensor assay. The LAL test showed that 256 microg of BNEP almost completely neutralized 2 ng LPS. In vivo, mice were randomized, intravenously injected with BNEP (0.5-10 mg/kg) or 1 mg/kg PMB, and then lethally challenged with 20 mg/kg LPS. We found that 5 mg/kg BNEP significantly protected mice from LPS challenge. In an endotoxemia rat model, animals were co-treated with 5 or 10 mg/kg BNEP and 10 mg/kg LPS via cardiac catheter. BNEP treatment resulted in significant reduction of tumor necrosis factor alpha (TNF-alpha) and IL-6, compared with LPS-only control animals. In addition, 10 mg/kg BNEP-treated animals showed a significant decrease in plasma endotoxin levels in comparison to animals treated with LPS alone. These results provide evidence that BNEP effectively neutralizes LPS in vitro and in vivo, and could protect animals from the lethal effects of LPS via decreasing plasma endotoxin and proinflammatory cytokines. Our work suggests that this peptide is worthy of further investigation as a possible novel treatment for septic shock.

Animals↗
PubMedDate not supplied

[Endotoxin content of samples of pasteurized milk: preliminary findings].

By Limulus lysate assay, endotoxin was found in pasteurized milk samples from commercial source. The range was 32 to 128 microgram per ml, without any change when the samples were refrigerated. By contrast, the endotoxin content rose 512 to 2048 microgram per ml when milk was maintained at room temperature for 24 hours and 1024 to 6400 microgram per ml when samples were examined after 72 hours. These findings suggest a possible clinical implication, and support the concept that Limulus assay appears to be a rapid, reliable, and sensitive test for a quality control in commercial milk samples.

Animals↗
PubMed1985

In vitro generation of procoagulant activity by Corynebacterium parvum-stimulated mononuclear leukocytes.

Thromboembolic complications are known in cancer patients after i.v. administration of Corynebacterium parvum. We examined the ability of this organism to induce production of procoagulant activity by human blood mononuclear leukocytes in vitro. After 4 hours incubation Corynebacterium parvum was an effective stimulant for mononuclear leukocytes, behaving in the same way as the typical gram-negative bacterium Escherichia coli, whereas mononuclear cells incubated with Staphylococcus aureus were not affected. Corynebacterium parvum used was found devoid of endotoxin by the Limulus assay and was not affected by Polymyxin B, which, on the contrary, inhibited Escherichia coli-induced production of procoagulant activity. Intact Corynebacterium parvum may be required for the production of procoagulant activity and, although this specific aspect of the research will require further study, from the exposed data it is concluded that such a production could be a factor contributing to the pathogenesis of the coagulopathy following Corynebacterium parvum therapy.

Blood Coagulation Tests↗
PubMed2004

[Countermeasures against non-specific reactions in the measurement of beta-glucan in plasma by alkaline treatment, chromogenic automated kinetic assay].

We investigated the detection of non-specific reactions in the measurement of plasma (1-->3)-beta-D-glucan (beta-glucan) and countermeasures against them using alkaline treatment, chromogenic automated kinetic assay (alkaline-kinetic assay). In this study, we reexamined the values of beta-glucan using the alkaline-kinetic assay with and without laminaran oligosaccharides (LO) as a kind of beta-glucan that blocks the Limulus reaction. The materials for this study were 584 plasma samples in which beta-glucan had been measured. These were taken from 232 patients in Kawasaki Medical School Hospital between January 2002 and March 2002. Non-specific reactions were judged by a calculated value under a LO additive condition. Determination as to whether or not the each time course of the Limulus reaction was influenced by a non-specific reaction was also studied by applying a non-specific reaction index set up independently. Non-specific reactions were recognized in 51.9% of the samples (81/156). The amount of non-specific reaction was 9.9 pg/ml or less in major samples. On the other hand, when the cut off value of the index for detection of non-specific reactions was set at 0.5, the sensitivity was 88.9% and specificity was 73.7%. The positive and negative predictive values were 93.5% and 60.9% respectively. Non-specific reactions can be approximately distinguished by applying the non-specific reaction index. By so doing, unnecessary initiation of anti fugal therapy in response to non-specific reactions can be avoided. Further prospective and radical studies of non-specific reactions in the alkaline-kinetic assay are necessary.

Adult↗