Water-stable perovskite-on-polymer fluorescent microspheres for simultaneous monitoring of pH, urea, and urease.

Perovskite materials have attracted attention due to their excellent optical and electrical properties; however, their unsatisfactory stability limits their application in biochemical detection. In this paper, CsPbBr3 perovskite quantum dots were successfully encapsulated in poly(styrene/acrylamide) microspheres, using a swelling-shrinking method. The manufactured perovskite microspheres (PDPS composites) not only maintained strong photoluminescence (PL) stability but also demonstrated great water solubility. Additionally, a real-time pH monitoring platform was constructed based on the prepared PDPS composites and dopamine, and the system showed a good linear relationship in a pH range of 4-12. Furthermore, urea could be hydrolyzed to produce hydroxyl groups, thereby increasing the pH of the solution. Therefore, this system was then extended for urea and urease detection. As a result, the detection limits of urea and urease were recorded as 1.67 µM and 2.1 mU/mL, respectively. This development provides an interesting demonstration of the expanding list of applications of perovskite materials.

Study of Serum Levels of Some Oxidative Stress Markers in Children with Helicobacter pylori Infection.

BACKGROUND: Helicobacter pylori are gram-negative spiral shaped bacteria, with sheathed flagella. H. pylori infection is one of the most common chronic infections in humans. Infection is usually acquired during childhood, and becomes a lifelong infection in most people unless treated. The aim of this study was to evaluate serum levels of oxidative stress indices in children with H. pylori infection. MATERIAL AND METHODS: The present study was carried out on 60 children infected with H. pylori including 28 males, 32 females with their age ranging from 7-10 years and mean age value of 8.5 ± 1.65 ( Group I). This study included also 60 children as a control group including 26 males, 34 females with their age ranging from 7-11 and mean age value of 8.99 ± 1.63 (Group II). For all children in groups I the following were done: Diagnosis of H. pylori infection through H. pylori stool antigen testing using enzyme immunoassay kit and gastric antrum mucosal biopsies which were tested for urease activity using Campylobacter like organism test (CLO test). Measurements of serum oxidative stress markers including Superoxide dismutase (SOD), Malondialdhyde, Glutathione, Catalase and Nitric oxide were done in patients and controls. RESULTS: Serum nitric oxide and reduced glutathione were significantly lower in patients compared to controls while serum MDA, Serum catalase and Serum SOD were significantly higher in patients compared to controls (nitric oxide was 91.111 ±6.366 in patients versus 107.211±2.121 in controls with p value of 0.001, reduced glutathione in patients was 2.457± 0.081 versus 2.889±0.491 in controls with p value of 0.001, serum MDA in patients was 140.22±5.18 versus 116.22±2.98 in controls with p value of 0.001, catalase was 401.645± 4.344 versus 278.221±71.712 in controls with p value of 0.001 and SOD in patients was 16.936±9.145 versus 5.578±0.231 in controls with p value of 0.001). CONCLUSION: H. pylori infection is associated with oxidative stress with significantly lower serum nitric oxide and reduced glutathione and significantly higher serum MDA, catalase and SOD in patients compared to controls. RECOMMENDATIONS: Antioxidants may be beneficial adjuvant treatment in H. pylori infection as H. pylori infection is associated with oxidative stress.

Dual-priming oligonucleotide-based multiplex PCR using tissue samples from the rapid urease test kit for the detection of Helicobacter pylori in bleeding peptic ulcers.

BACKGROUND: In patients with peptic ulcer bleeding (PUB), diagnostic tests for Helicobacter pylori (H. pylori) infection have low sensitivity. The aim of our study was to investigate the diagnostic yield of dual-priming oligonucleotide-based multiplex (DPO)-PCR using tissue samples from the rapid urease test (RUT, CLO(®)test) kit in patients with PUB. METHODS: We prospectively enrolled patients with PUB. During second-look endoscopy, gastric biopsy specimens for histology and RUT were obtained from a total of 170 patients. DPO-PCR tests were performed on tissue samples obtained from the CLO(®)test kit. If testing for H. pylori was negative, endoscopy with re-biopsy was performed 8 weeks after the bleeding episode. RESULTS: H. pylori-associated bleeding was confirmed in 64.1% (109/170) of the patients. At the bleeding episode, the diagnostic sensitivities of RUT, histology, and DPO-PCR test were 47.7% (52/109), 71.6% (78/109) and 97.2% (106/109), respectively (p<0.01). The specificity of the DPO-PCR test was 91.8% (56/61). The positive predictive value (PPV) of the DPO-PCR test was 95.5% (106/111), and its negative predictive value (NPV) was 94.9% (56/59). CONCLUSIONS: In patients with PUB, the DPO-PCR test could be a useful diagnostic tool for H. pylori infection. Particularly given a negative RUT result, subsequent DPO-PCR testing of tissue samples from the CLO(®)test kit could be of considerable benefit.

Correlation of serum antibody titres with invasive methods for rapid detection of Helicobacter pylori infections in symptomatic children.

Helicobacter pylori (H. pylori) is causally associated with peptic ulcer disease and gastric carcinoma. Typically, children get infected during the first decade of life, but diseases associated with H. pylori are seen mainly in adults. Multiple diagnostic methods are available for the detection of H. pylori infection. The aim of this study was to evaluate the correlation and diagnostic accuracy of three invasive methods [rapid urease test (RUT), histology and bacterial culture] and one non-invasive method (IgG serology) for diagnosis of H. pylori infection in a prospective cohort study conducted on 50 symptomatic children between two and eighteen years of age. Endoscopies with gastric biopsies were performed for RUT, culture and histopathological examination, respectively. IgG antibodies were measured in patient sera using a commercially available enzyme-linked immunosorbent assay (ELISA). RUT and positive H. pylori IgG antibodies were concordant in 88% (44/50) of patients. Both tests were negative in 32% (16/50), and both were positive in 56% (28/50). Disagreement occurred in 12% (6/50) of the patients: three of them (6%) had positive RUT and negative H. pylori IgG, and another three (6%) had negative RUT and positive H. pylori IgG. A combination of RUT with non-invasive serology constituted the optimum approach to the diagnosis of H. pylori infection in symptomatic children. The non-invasive serological test (ELISA) could not be used alone as the gold standard because it cannot distinguish between active and recently treated infection; and bacterial culture could not be used alone because of its low sensitivity.

Helicobacter pylori negative, non-steroidal anti-inflammatory drug-negative peptic ulcers in India.

INTRODUCTION: The past decade has witnessed a global rise in the prevalence of peptic ulcer disease which is unrelated to non-steroidal anti-inflammatory drugs (NSAIDs) or Helicobacter pylori infection. Although initially recognized in the West, this disease is being increasingly recognized in the Asian population. The higher risk of bleeding and ulcer recurrence in this subgroup of patients highlights the clinical importance of analyzing the changing trends of peptic ulcer disease in developing countries. AIMS: To assess the proportion of non-NSAID, non-H. pylori peptic ulcer disease in an Indian cohort of patients with peptic ulcer disease managed at a tertiary care center; and to compare the gastric and duodenal ulcer subgroups in these patients. METHODS: Patients diagnosed with peptic ulcer disease were screened for a history of NSAID use and those with a negative history were tested for H. pylori using a combination of rapid urease test (RUT) and (14)C-urea breath test (UBT). Only those cases which tested negative for both the tests were considered 'H. pylori-negative'. Serum gastrin was measured in all patients included in the study. RESULTS: Seventy-four gastric ulcer (GU) and 54 duodenal ulcer (DU) patients with no history of NSAID use were enrolled. Of these, 36 GU (45.9%) and 16 DU (29.6%) patients were H. pylori-negative. The proportion of non-NSAID non-H. pylori gastric ulcers was significantly higher than duodenal ulcers (p < 0.05). However, patients who tested negative for H. pylori did not differ significantly from those who tested positive with regard to age, gender, serum gastrin level, and presence of risk factors, like smoking and alcoholism. CONCLUSION: The current study indicates existence of high proportion of non-NSAID, non-H. pylori peptic ulcer disease in Indian patients.

Eradication of Helicobacter pylori may be beneficial in the management of Alzheimer's disease.

Infectious agents have been proposed as potential causes of Alzheimer's disease (AD). Recently, we documented a high prevalence of Helicobacter pylori (Hp) infection in patients with AD. We aim to access the effect of Hp eradication on the AD cognitive (MMSE: Mini Mental State Examination and CAMCOG: Cambridge Cognitive Examination for the Elderly) and functional (FRSSD: Functional Rating Scale for Symptoms of Dementia) status parameters. In the first part of the study, a total of 50 consecutive patients with AD and 30 age-matched anaemic controls underwent an upper gastrointestinal endoscopy, and gastric mucosal biopsies were obtained to detect the presence of Hp infection by histologic analysis and rapid urease test. Serum anti-Hp-specific IgG level was analysed by enzyme-linked immunosorbent assay. In the second part, Hp-positive AD patients received a triple eradication regimen (omeprazole, clarithromycin and amoxicillin), and all patients were followed up for 2 years, while under the same treatment with cholinesterase inhibitors. Hp was detected in 88% of AD patients and in 46.7% of controls (P < 0.001). Hp eradication was successful in 84.8% of treated patients. At the 2-year clinical endpoint, cognitive and functional status parameters improved in the subgroup of patients where Hp eradication was successful (P < 0.001 and P = 0.049 for MMSE and CAMCOG, respectively; P < 0.001 for FRSSD), but not in the other patients. Hp eradication may positively influence AD manifestations, suggesting a possible common link between Hp and AD.

[Helicobacter pylori and peptic disease: comparative study of the diagnostic methods]. / Helicobacter pylori e doença péptica: estudo comparativo de métodos diagnósticos.

Prospective endoscopic study of 150 patients revealed chronic gastritis in 109 (72.6%), gastric ulcer in 6 (4%), chronic duodenitis in 9 (6%) and duodenal ulcer in 26 (17.4%). Searching for Helicobacter pylori, positive urease test was observed in 103 (68.67%), histologic evidence in 104 (69.33%) and positive serologic test in 98 (65.33%), without statistical difference. The urease test is recommended in the diary medical practice, for the patients who also will benefit themselves with the endoscopic diagnosis. On the other hand, the serologic test is useful when the endoscopy of the upper digestive tract cannot or must not be realized.

Helicobacter pylori e doença péptica: estudo comparativo de métodos diagnósticos / Helicobacter pylori and peptic disease: comparative study of the diagnostic methods

Foram estudados, prospectivamente, 150 pacientes. Estudo endoscópico revelou gastrite crônica em 109 pacientes (72,6 por cento), úlcera gástrica em 6 (4 por cento), duodenite crônica em 9 (6 por cento) e úlcera duodenal em 26 (17,4 por cento). Quanto à avaliação metodológica para pesquisa do Helicobacter pylori, 103 (68,67 por cento) apresentaram teste da urease positivo, 104 (69,33 por cento), positividade histopatológica e 98 (65,33 por cento), positividade sorológica. Não houve diferença estatística entre os métodos. Pela facilidade de realização, o teste da urease credencia-se como o de melhor indicação nos pacientes que também se beneficiarão com o diagnóstico endoscópico. Caso a endoscopia digestiva alta não possa ou não deva ser realizada, está recomendado o teste sorológico.

Prospective endoscopic study of 150 patients revealed chronic gastritis in 109 (72.6 percent), gastric ulcer in 6 (4 percent), chronic duodenitis in 9 (6 percent) and duodenal ulcer in 26 (17.4 percent). Searching for Helicobacter pylori, positive urease test was observed in 103 (68.67 percent), histologic evidence in 104 (69.33 percent) and positive serologic test in 98 (65.33 percent), without statistical difference. The urease test is recommended in the diary medical practice, for the patients who also will benefit themselves with the endoscopic diagnosis. On the other hand, the serologic test is useful when the endoscopy of the upper digestive tract cannot or must not be realized.

Occurrence of serum class G immunoglobulins interacting with specific antigens of Helicobacter pylori in patients with unstable coronary artery disease and in symptomless individuals.

An impact of Helicobacter pylori on the process of atherogenesis may be related to the intensity of humoral response against selected specific antigens of this bacteria. We performed serological studies in which the recognition of 7 selected antigens was possible. The investigated group consisted of 56 patients hospitalized due to unstable angina pectoris. The control group consisted of 29 symptomless volunteers. The levels of class G serum immunoglobulins interacting with glycine extract (GE) of H. pylori antigens were assessed by ELISA test in both groups. The same sera were tested by the Milenia blot H. pylori IgG system. In this assessment the presence of IgG antibodies interacting with antigens of molecular weight of 120, 87, 64, 35, 30, 26, and 20 kDa was estimated separately for every listed antigen. The results revealed significant differences between investigated groups in the prevalence of anti-GE IgG (unstable angina - 100% vs. controls - 60%) and in the level of such antibodies expressed as total optical density units--OD450 (6.1 +/- 3.0 vs. 3.4 +/- 3.0 respectively, p<0.05). However, anti-GE IgG detected in the sera of patients as well as controls reacted with similar frequency with selected H. pylori antigens: highly specific (120, 87, 64, 30 kDa) and specific (35, 26, and 20 kDa). We conclude, that although H. pylori infection is so common and mainly associated with gastroduodenal symptoms, it is also recognized by serological methods with high prevalence in patients with coronary artery disease, and less frequently in symptomless individuals. The humoral response against H. pylori in class G immunoglobulins in patients with unstable angina is characterized by higher levels of anti-H. pylori IgG but not by the higher prevalence of serum IgG interactions with the highly specific and specific H. pylori antigens. Such infection could be considered as a cofactor for atherogenesis by inducing strong humoral response against surface antigens of this bacteria.

Helicobacter pylori diagnosis in patients with liver cirrhosis.

BACKGROUND: In cirrhotics, Helicobacter pylori infection is the major cause of peptic lesions, which are an important cause of upper intestinal haemorrhage in these patients. However, some diagnostic methods are not accurate for H. pylori detection in cirrhotics. AIMS: The study assessed the accuracy of different diagnostic methods for H. pylori detection in cirrhotics with and without gastroduodenal lesions. METHODS: The study population comprised of 53 cirrhotics. All patients underwent upper endoscopy: three biopsies were taken in the antrum and three in the gastric body. Four biopsies were used for Giemsa staining, while two were used for a rapid urease test. A blood sample was obtained for serology using Western blotting, and a [13C]urea breath test was performed in all patients. Histological assessment was regarded as the gold standard for diagnosis of H. pylori infection. RESULTS: H. pylori infection was detected at histological assessment in 28 (52.8%) patients. The [13C]urea breath test, rapid urease test, and serology were positive in 27 (51%) patients, 23 (43.4%) patients, and 34 (64.1%) patients, respectively. Sensitivity and specificity were 92.9 and 96% for the [13C]urea breath test, 78.6 and 96% for the rapid urease test, and 78.6 and 52% for serology. CONCLUSIONS: The [13C]urea breath test is very accurate in cirrhotics, whilst both serology and the rapid urease test give disappointing results.

Evaluation of a Western blot technique (Helicoblot 2.1) for the diagnosis of Helicobacter pylori infection in children.

AIM: We evaluated the performance of Helicoblot 2.1 which differentiates the reactivity to each of the various Helicobacter pylori antigens, and compared the results with those obtained by standard techniques (rapid urease test and histological examination of gastric biopsy) in symptomatic children of different ages living in Antalya, Turkey. METHODS: Eighty-eight children (mean age, 9.15 years) were divided into two groups. The first group included 66 children who were found to be infected with H. pylori. The second group included 22 children who were negative for H. pylori. Serum samples collected from all patients were tested for H. pylori IgG antibodies by immunoblot assay (Helicoblot 2.1). RESULTS: The sensitivity, specificity, positive and negative predictive values for detection of H. pylori infection were 80%, 100%, 100% and 85%, respectively. In children under 7 years of age, the sensitivity of the test was found to be lower than other age groups (P<0.05). No relationship was found between peptic ulcer and cagA antibody positivity (P>0.05). CONCLUSION: Helicoblot 2.1 is a useful non-invasive diagnostic tool for H. pylori infection in children over 6 years of age.

[The preparation and application of cross-linked urease aggregates].

Urease was immobilized in a simple and effective way by physical aggregation using a precipitant-ammonium sulfate, followed by chemical cross-linking using a bifunctional reagent-glutaraldehyde to form insoluble Cross-linked urease aggregates (CLUAs). The optimum pH, optimum temperature and Km of CLUAs were 8.0, 70 degrees C and 0.021 mol/L respectively. Compared with that of free urease, the thermal stability, storage stability and resistance of cross-linked urease aggregates to the exogenous proteolysis were enhanced. The efficacy of CLUAs for the treatment of rats with chronic renal failure was also studies. The rats with chronic renal failure caused by adenine were divided into 3 groups randomly:the control group (fed with 10 mL water /kg per day), Coated Aldehyde Oxystarch (CAO) group (fed with 20 g CAO /kg and 10 mL water /kg per day) and CLUAs + CAO group (fed with 20 g CAO /kg and 10 mL CLUAs /kg per day) in which CAO was used to absorb the ammonia produced from urea. The contents of BUN and Scr in serum before and after 2 weeks treatment were determined. In three groups, the level of Scr decreased slightly (P = 0.922, 0.972 and 0.225 > 0.05 respectively) after treatment. The level of BUN was not changed (P = 0.211 > 0.05) in the control group, but decreased greatly BUN in both CAO group and CLUAs + CAO group (P = 0.004 < 0.05 and P < 0.001 respectively). Furthermore, the decrease of the BUN level after treatment in the CLUAs + CAO group was more remarkable than that in the CAO group (P = 0.016 < 0.05), which showed that the CLUAs + CAD system was more efficient than the CAO system for the removal of urea in serum.

Comparison of two new rapid serology tests for diagnosis of Helicobacter pylori infection in Chinese patients.

BACKGROUND: Rapid serology test is a simple and convenient way for diagnosing Helicobacter pylori infection. However performances of these tests are usually less satisfactory than expected, particularly in developing countries. AIM: To evaluate the performances of two newly developed rapid serology tests for Helicobacter pylori infection. PATIENTS: Consecutive Chinese dyspeptic patients undergoing upper gastrointestinal endoscopy. METHODS: Gastric biopsies were obtained from antrum and corpus for rapid urease test and histological examination. Diagnosis of Helicobacter pylori infection was based on two or more positive results in rapid urease test, histology and [13C] urea breath test. Patients' sera were tested against two rapid serology tests: ASSURE Hp Rapid Test (Genelabs Diagnostics, Singapore) and SureStep (Applied Biotech, San Diego, CA, USA). RESULTS: A total of 148 patients were evaluated and Helicobacter pylori infection was diagnosed in 78 (53%) patients by gold standard. The sensitivities of ASSURE Hp and SureStep were, respectively, 94% and 71% (p=0.0003). Specificities of the two test kits were both 90%. The overall accuracy of ASSURE Hp was significantly higher than SureStep (92% versus 80%, p=0.004). CONCLUSION: Both rapid serology tests appear to be specific in diagnosing Helicobacter pylori infection in the Chinese populations. However the ASSURE Hp test is more sensitive and accurate than the SureStep test.

Encapsulation of PEG-urease/PEG-AlaDH enzyme system in erythrocyte.

No intravenously injectable enzyme preparate containing urease as an alternetive to hemodialysis, hemoperfusion and CAPD systems in patients having chronic renal failure has been encountered in literature. In this study, it has been aimed to convert blood urea to alanine by using PEG-urease/PEG-AlaDH enzyme pair encapsulated within living erythrocyte. In this system, urea is decomposed into NH3 and HCO3- and the ammonia released is converted into alanine by reacting pyruvate under the catalytic action of alaninedehydrogenase. The production of pyruvate and NADH by erythrocyte required in the second stage of the reaction will make the process a feasible and ceaseless one. The success of the system will enable the renal patients with diabetes mellitus. Urease and AlaDH were covalently immobilized on activated PEG. PEG-urease/PEG-AlaDH were encapsulated in erythrocyte (1/1)(v/v) by using slow dialysis methods. The activity of enzyme system, encapsulation yield and hemogram analysis were determined for each sample.

Diagnostic methods for detecting forms and strains of Helicobacter pylori and evaluation of its eradication.

Diagnostic methods for detecting forms and strains of Helicobacter pylori isolated from biopsy specimens of gastric mucosa in 28 patients with duodenal ulcers and evaluation of its eradication were compared. Biopsy specimens from all patients were tested for the presence of H. pylori by the urease test, histological method, and PCR with species-specific primers before and after treatment. H. pylori infection was detected in all patients before treatment, the mean titer of serum IgG being 36.7+/-16.6 U/ml. Biopsy specimens positive for H. pylori in PCR were subjected to restriction analysis of specific PCR-amplified genes or their fragments. The fingerprint analysis gave electrophoregrams of restriction products amplified fragment of flaA gene of H. pylori in 7 patients. Differences in restriction maps indicate the presence of 5 H. pylori strains in the studied samples.

Comparison of PCR and common clinical tests for the diagnosis of H. pylori in dyspeptic patients.

Helicobacter pylori has been recognized as a major gastric pathogen. The objective of this study was to assess the diagnostic value of common clinical tests to detect H. pylori infection, by comparison with PCR. Serum and gastric biopsy specimens from 106 dyspeptic patients were examined. Serology was performed with Pyloriset Dry test, and biopsies were examined histologically, for rapid urease activity and PCR amplification of an ureA gene segment of H. pylori. PCR primers were specific for H. pylori and required at least 1.47 pg of H. pylori DNA, corresponding to about 800 bacterial cells. According to serology, histology, rapid urease, and PCR, positive results were respectively found in 56%, 86%, 64%, and 85% of dyspeptic patients, primarily with gastritis. Relative to PCR, the sensitivity (and specificity) was 55% (38%) for serology, 86% (13%) for histology, 70% (69%) for urease. When combining histology and urease, Bayesian analysis of data indicated no advantage of using combined methods over rapid urease test alone. Histology should not any longer be considered a gold standard test for Helicobacter pylori. Urea breath test still seems the first option for non invasive diagnostic. If an invasive diagnostic is justified, highly specific and sensitive molecular methods should be used to examine specimens.

Estudio de correlación entre la urea serica y la urea en saliva

La Insuficiencia Renal Crónica Terminal (IRCT) es un problema de salud pública a nivel mundial. Para detectar pacientes con Insuficiencia Renal Crónica (IRC) en estadios iniciales se requiere de un método de screening poblacional simple, no invasivo y de bajo costo. El objetivo del estudio fue determinar el grado de correlación de la úrea en saliva con la úrea sérica en personas sanas y con diversos grados de IRC. El presente estudio se realizó en personas sanas y pacientes con IRC que acudieron al Servicio de Nefrología del Hospital Nacional Cayetano Heredia, con el apoyo del laboratorio de Nefrología de la Universidad Peruana Cayetano Heredia. Se evaluaron 27 casos (13 varones y 14 mujeres) con una edad de 35 ñ 18, la úrea sérica fue normal (menor de 40 mgr por ciento) en 8 casos, y patológica en pacientes con IRC en 19 casos con valores que variaron desde 51 mgr por ciento hasta 357 mgr por ciento. A todos los pacientes se les realizó dosaje de úrea en saliva y úrea sérica simultáneamente. Los datos se analizaron mediante el coeficiente de correlación de la r de Pearson encontrándose un coeficiente de correlación de 0.9772. Se concluye que la úrea en saliva se correlaciona perfectamente con la úrea sérica. Palabras claves: Urea. Saliva. Sangre.

The evolutionarily conserved ribosomal protein L23 and the cationic urease beta-subunit of Yersinia enterocolitica O:3 belong to the immunodominant antigens in Yersinia-triggered reactive arthritis: implications for autoimmunity.

BACKGROUND: Reactive arthritis (ReA) is a T cell mediated inflammatory process. The immune response is primarily directed against a triggering organism, although autoimmunity has been invoked in long-lasting, antibiotic-resistant disease. Although a variety of different species are known to trigger Reactive arthritis, the clinical manifestations are strikingly similar as well as closely associated to the HLA-B27 (70%). MATERIALS AND METHODS: Various antigenic fractions and single antigens of Yersinia enterocolitica were prepared, and their immunological activity was assessed by proliferation of synovial fluid mononuclear cells from 10 Reactive arthritis patients. The gene encoding one hitherto unknown antigen has been sequenced. Nonapeptides deduced from sequences of the target antigens were tested in an assembly assay. RESULTS: Two immunodominant proteins of Yersinia enterocolitica were found, one being the urease beta-subunit and the other the 50 S ribosomal protein L23. The latter has been sequenced and belongs to the evolutionarily conserved ribosomal proteins with homology to procaryotes and eucaryotes. One nonapeptide derived from the urease beta-subunit was identified as a possible epitope for HLA-B27-restricted cytotoxic T cells by its high affinity. This epitope is also highly conserved. CONCLUSION: Sharing of conserved immunodominant proteins between different disease triggering microorganisms could provide an explanation of the shared clinical picture in Reactive arthritis. Moreover, autoimmunity in Reactive arthritis might be mediated by antigen mimicry between evolutionarily conserved epitopes of ribosomal proteins and their host analogs.

Continuous beds. Their applicability for immobilization of proteins.

An epoxy-activated continuous bed can be prepared for immobilization of proteins in a simple, rapid, and cost-effective way. The concentration of epoxy groups on the continuous bed was as high as 600 mumol/mL compressed bed (compression of the bed decreases the peak broadening). Human transferrin, human serum albumin and particularly urease were employed as model proteins. The immobilization of urease was virtually completed within 1 h in 1 M potassium phosphate, pH 7.4. The binding capacity was 97 mg of urease/mL compressed bed. This bed is of clinical interest, since it is inexpensive to prepare and permits reproducible enzymatic determination of urea in serum and urine (the chromatographic step is finished within 1-2 min).