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.

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.

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.

Enzyme loading of electrically homogeneous human red blood cell ghosts prepared by dielelctric breakdown.

Human red blood cell ghosts were prepared by electrical haemolysis at 0 degrees C in isotonic solutions using a discharge chamber which was part of a high voltage circuit. The size distribution of the ghosts was normally distributed, the modal (=mean) volume was approx. 115 mum3, performing the electrical haemolysis in the following solution: 105 mM KCI, 20 mM NaCL, 4mM MgCl2, 7.6 mM Na2HPO4, 2.94 mM NaH2PO4, 10 mM glucose, pH 7.2. Resealing was carried out at o degrees C for 10 min (after the haemolytic step) and then for further 20 min at 37 degrees C. The mean volume of the ghost preparation could be changed by variation of the phosphate concentration in the above solution replacing a part of NaCl by phosphate (5 mM phosphate: 94 mum3, 15 mM phosphate: 135 mum3). The breakdown voltage of the ghost cell membranes measured with a hydrodynamic focusing Coulter Counter depends on the mean volume (94 mum3 = 1.04 V, 134 mum3 = 1.36 V). On the other hand, the breakdown voltage is constant throughout each size distribution pointing to an "electrically homogeneous" ghost preparation. The sensitiviity of the Coulter Counter to detect electrical inhomogeneities in the membranes of a ghost population is demonstrated by dielectric breakdown measurements of an apparently normally distributed ghost preparation containing two different "electrically homogeneous" ghost population i.e. with two different breakdown voltages. The ghost cells obtained by electrical haemolysis in the above solution containing 10mM phosphate were fairly impermeable to sucrose and behave like an ideal osometer. It is further demonstrated that ghost cells can be loaded with enzymes (e.g. urease) and drugs using this technique and that these loaded ghost cells can be used as bioactive capsules for clinical application.

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.

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.

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.

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.

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.

Biological activity of urease formulated in poloxamer 407 after intraperitoneal injection in the rat.

The advent of genetic engineering has resulted in a proliferation of protein pharmaceuticals available for a variety of therapeutic needs. However, the formulation and delivery of these proteins remain an intriguing challenge. Polymer-based protein drug delivery systems continue to be investigated, although many of the fabrication techniques used to incorporate proteins into the polymer matrix or device result in irreversible inactivation (denaturation) of the proteins. A well-characterized model enzyme, urease, was formulated in 33% (w/w) poloxamer 407 (Pluronic F-127) vehicle and injected intraperitoneally (ip) into rats in an attempt to achieve both preservation of biological activity and sustained release of the protein. The resulting ammonia concentration in plasma-time profiles were compared with those for rats injected with an identical dose (27.6 units of activity per 200 g of body weight) of urease dissolved in pH 7 phosphate buffer. Neither a pH 7 phosphate buffer solution nor poloxamer 407 (33%, w/w) dissolved in pH 7 phosphate buffer, when injected ip into rats, resulted in elevated ammonia levels in plasma. The time to reach a maximum ammonia level in plasma was increased approximately threefold following the injection of the urease-poloxamer 407 formulation, compared with that in control rats administered an identical dose of urease in solution. In addition, hyperammonemia was extended almost threefold in treated rats compared with control rats, without untoward effects. However, prolonged hyperammonemia in animals receiving an ip injection of the urease-poloxamer 407 formulation may have potentially resulted from the reduced clearance of ammonia and ammonium ion in the proximal tubules of the rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[The relationship of duodenal peptic ulcer and gastroduodenitis to a chronic staphylococcal infection]. / O sviazi iazvennoi bolezni dvenadtsatiperstnoi kishki i gastroduodenita s khronicheskoi stafilokokkovoi infektsiei.

Tonsillar and pharyngeal smears revealed growth of pathogenic microorganisms, mainly of Staphylococcus aureus, in 58.0 +/- 3.7% of 174 patients with duodenal ulcer and gastroduodenitis during remission or unstable remission, in 40.0 +/- 5.3% of 85 patients with other gastroenterological diseases and in 17.5 +/- 6.0% of 40 subjects constituting control group. Urease activity ratio (biological marker of Helicobacter pylori) was found to be approximately the same in every group of patients vs 11.1 +/- 6.2% of 27 healthy persons. Pathogenetic mechanisms of relation between duodenal ulcer, chronic gastroduodenitis and chronic focuses of infection are discussed. Lymphatic pharyngeal ring is supposed to be biotopical for Helicobacter pylori.

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.

[Inhibition of urease by hypoglycaemic drugs (author's transl)]. / Inhibición de la ureasa por fármacos hipoglucemiantes derivados de la sulfonilurea

The effect of oral hypoglycaemic drugs (derived from sulphonylurea) on urease activity in the quantitative determination of urea has been studied. These compounds have been found to produce a competitive inhibition of enzyme activity with respect to substrate. Possible interference of these antidiabetic agents upon urea analysis is discussed.

Successful use of two new reactor types in sheep.

The new enzyme reactor types based on the use of biogenic material (red cell ghosts and crosslinked fibrin) were tested in vitro and in vivo (sheep). The main characteristics of the reactors were highly maintained substrate affinity, high enzyme activity per unit surface and good physicochemical stability.

[Interference of hemolysis in plasma urea determination. A comparison of 2 methods: classical Berthelot urease and the modified Berthelot urease]. / Interferenza dell'emolisi sulla determinazione dell'urea plasmatica. Confronto tra due metodiche: ureasi-Berthelot classica ed ureasi-Berthelot modificata.

The authors have tested the interference of the hemoglobin by two routine methods ( Berthelot classic and Berthelot modified) for the determination of plasmatic urea. From their work it appears that Berthelot classic method already presents a very sensible positive interference for hemoglobin at 0.04 g/dl level while for the Berthelot modified method such interference begins to be significant only for those values which are than 1.25 g/dl level. The correlation between these two methods, tested by limpid and lacking in hemolysis plasmas, is very good, so the authors think the Berthelot modified method is more respondent to the exigence of the routine as it is not exceptional the case to have to execute anyhow some determinations of urea and plasmas which have a partial hemolysis.