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At least 523 records · Page 29Linked to original sources
PubMed1999

Isolation of an asporogenic (spoOA) protective antigen-producing strain of Bacillus anthracis.

We found that Congo red agar allows identification of sporulation-deficient Bacillus anthracis. Using Congo red agar, we isolated an asporogenic derivative of the protective antigen-producing strain B. anthracis delta Sterne-1(pPA102). Polymerase chain reaction and Southern hybridization analyses of DNA from the asporogenic mutant revealed that a deletion was present in spoOA, an essential gene for the initiation of sporulation. The deletion also encompassed the spoIVB homologue and a portion of the recN homologue. The avirulent spoOA strain delta Sterne-1(pPA102)CR4 is suitable for the safe production of protective antigen without endospore contamination of the vaccine production facility.

Agar↗
PubMed1996

Effects of P2-purinoceptor antagonists on degradation of adenine nucleotides by ecto-nucleotidases in folliculated oocytes of Xenopus laevis.

The aim of the present study was to examine the effects of a number of P2-purinoceptor antagonists on degradation of adenine nucleotides by Xenopus laevis oocyte ecto-nucleotidase. Folliculated oocytes readily metabolize all three naturally-occurring nucleotides, the order of preferential substrates being ATP >ADP > AMP. The degradation of ATP and ADP was decreased significantly in the presence of several P2X- and P2Y-purinoceptor antagonists, including suramin, PPADS, Cibacron blue, Coomassie Brilliant blue, Evans blue, Trypan blue, Congo red, and PIT (each compound was used at 100 microM). All these compounds inhibited the degradation of ATP by up to 60%, whereas the hydrolysis of ADP was inhibited by Congo red and PIT by 75-80%. In addition, DIDS (100 microM) and TNP-ATP (100 microM) selectively inhibited the breakdown of ATP, and sodium azide (10 mM) selectively inhibited the breakdown of ADP. The enzymatic breakdown of either ATP or ADP was unaffected by 8-pSPT (100 microM), an antagonist of P1-purinoceptors, or by oxidized ATP (100 microM), an antagonist of P2Z-purinoceptors. The degradation of AMP was prevented completely by PIT (100 microM) and ingibited significantly by Congo red (100 microM). In conclusion, the present study shows that most of currently available antagonists of P2-purinoceptors inhibit the enzymatic breakdown of extracellular ATP and ADP. The inhibitory effect on ecto-nucleotidase activity should be taken into account when these antagonists are used in pharmacological experiments.

Adenine Nucleotides↗
PubMed2001

Evaluation of 99mTc-MAMA-chrysamine G as an in vivo probe for amyloidosis.

To date, systemic amyloidosis is diagnosed histologically using Congo red staining or in vivo using iodine-123 labelled serum amyloid P component (123I-SAP) scintigraphy. We developed 99mTc-MAMA-CG, a 99mTc-labelled derivative of the lipophilic Congo red analogue chrysamine G (CG), as a possible alternative to 123I-SAP. In vivo 99mTc-MAMA-CG scintigraphy, performed in chickens with spontaneous joint amyloidosis, resulted as soon as 10 min after injection in scintigraphic images showing uptake of activity in amyloid-loaded organs (liver, joints). One of these chickens was studied also with 123I-SAP resulting in scintigraphic images revealing 123I-SAP binding to amyloid deposits in the liver. However, up to 11 h after injection no radioactivity was visible in the amyloid positive joints. In vitro autoradiography, performed on sections of chicken joints with Enterococcus faecalis induced amyloid arthropathy (chjAA), demonstrated the failure of 99mTc-MAMA-CG to bind significantly to amyloid deposits in the presence of 10 microM Congo red The specificity of 99mTc-MAMA-CG localisation was also established by the absence of 99mTc-MAMA-CG binding in non-amyloidotic organs in vitro and in vivo. 99mTc-MAMA-CG did not show any sign of acute toxicity. These findings establish the usefulness of 99mTc-MAMA-CG as a non-invasive in vivo diagnostic probe in chickens with amyloid arthropathy and suggest that it may also be applicable to human amyloidosis.

Amyloid↗
PubMed2004

Biofilm detection and the clinical significance of Staphylococcus epidermidis isolates.

The ability of Staphylococcus epidermidis to produce biofilm was compared in 147 clinically significant strains repeatedly isolated from blood cultures of patients with bloodstream infection and in 147 strains isolated from skin. The strains were examined for the presence of ica operone, for the ability to form biofilm by Christensen's test-tube method and for the production of slime by Congo Red agar method. The ica operone was found in 92 (62.6 %) blood isolates and in 44 (29.9) isolates from skin. Christensen's test-tube method was positive in 79 (53.7) and 33 (22.4), Congo Red agar method in 64 (43.5) and 31 (21.1) of blood and skin isolates, respectively. All three methods were more frequently positive in clinically significant isolates from blood than in strains isolated from skin. The detection of ica operone and the Christensen's test-tube method showed better correlation with the clinical significance than the Congo Red agar method.

Bacteremia↗
PubMed1993

[Comparison of 2 methods of detecting slime production by coagulase-negative staphylococci].

In the series of 212 coagulase-negative staphylococci strains isolated from blood cultures, in which the slime production was tested by means of two methods--a method using agar with Congo red and a Christensen method--S. epidermidis, S. haemolyticus and S. hominis were identified most frequently (in 69.3%, 18.4% and 6.6%, respectively). The slime production was detected by both methods in 28 strains (13%) of four species, most often in S. epidermidis (in 17%). By comparing the Congo red agar method with the Christensen method the sensitivity and specificity of the former was determined (85% and 99%, respectively). Thus the Congo red agar method for the detection of slime production by staphylococci seems to be a reliable tool.

Bacteriological Techniques↗
PubMed2004

Sonication of proteins causes formation of aggregates that resemble amyloid.

Despite the widespread use of sonication in medicine, industry, and research, the effects of sonication on proteins remain poorly characterized. We report that sonication of a range of structurally diverse proteins results in the formation of aggregates that have similarities to amyloid aggregates. The formation of amyloid is associated with, and has been implicated in, causing of a wide range of protein conformational disorders including Alzheimer's disease, Huntington's disease, Parkinson's disease, and prion diseases. The aggregates cause large enhancements in fluorescence of the dye thioflavin T, exhibit green-gold birefringence upon binding the dye Congo red, and cause a red-shift in the absorbance spectrum of Congo red. In addition, circular dichroism reveals that sonication-induced aggregates have high beta-content, and proteins with significant native alpha-helical structure show increased beta-structure in the aggregates. Ultrastructural analysis by electron microscopy reveals a range of morphologies for the sonication-induced aggregates, including fibrils with diameters of 5-20 nm. The addition of preformed aggregates to unsonicated protein solutions results in accelerated and enhanced formation of additional aggregates upon heating. The dye-binding and structural characteristics, as well as the ability of the sonication-induced aggregates to seed the formation of new aggregates are all similar to the properties of amyloid. These results have important implications for the use of sonication in food, biotechnological and medical applications, and for research on protein aggregation and conformational disorders.

Amyloid↗
PubMed1992

Unusual renal deposit in mixed connective tissue disease.

We describe a patient with clinical signs of mixed connective tissue disease who developed nephrotic syndrome. The kidney biopsy revealed glomerular and vascular deposits that stained positive with Congo red and showed a green birefringence. The Congo red positivity became negative in sections treated with potassium permanganate. Peroxidase-antiperoxidase staining with anti-AA antibodies was strongly positive. Ultrastructurally, although the deposits were similar to amyloid, they were about twice the size of amyloid fibrils. To our knowledge, the deposition of an amyloidlike material that shows the histochemical and immunohistochemical features of amyloid AA but is lacking the distinctive ultrastructural characteristics of amyloid fibrils has not been described.

Amyloid↗
PubMed1987

[A case of a primary localized amyloidosis (amyloid tumor) of the renal pelvis and ureter].

A 62-year-old woman complaining of asymptomatic hematuria was hospitalized. Although a cytologic examination of the urine was negative, abnormal findings in the right renal pelvis by DIP, RP and CT led us to suspect a pelvic tumor, and a right nephroureterotomy was performed. Light microscopy revealed deposits of amorphous, eosinophilic material in the pelvis and proximal portion of upper ureter, however tumor cells were not found. Electron microscopy revealed that these materials were aggregates of linear, non-branching fibrils, measuring about 8 nm in diameter. Histochemically, these were seen to be consistent with amyloid, producing an apple-orange birefringence with Congo red staining under a polarized light. Alkali Congo red staining after pretreatment of KMnO4 demonstrate that this amyloid protein was composed largely of AA protein in addition to lesser amounts of non-AA protein, and a primary localized amyloidosis (amyloid tumor) was diagnosed. A clinicopathologic study that was performed on 12 cases of primary localized amyloidosis of the pelvis, including our case, also is reported.

Amyloidosis↗
PubMedDate not supplied

[Yersinia enterocolitica strains of bovine origin isolated in San Luis, Argentina: virulence, enterotoxigenicity, and antibiotic sensitivity].

Eleven Yersinia enterocolitica strains isolated from bovine tongues and classified as B1 0:5 Lis Xz (8), B2 0:9 Lis X3 (2), nontypable (1), were examined for the following virulence-associated characteristics: autoagglutination, calcium dependency, Sereny test, congo red binding and presence of 40-48 MDa plasmids. Heat-stable enterotoxin production was also determined. Antibiotic susceptibility was assayed according to the modified Bauer-Kirby's method. Two Y. enterocolitica B1 0:5 Lis Xz strains were positive for autoagglutination, calcium dependency and congo red binding; both exhibited nearly 40 MDa plasmids and one of them was enterotoxigenic. The other strains did not carry virulence-associated plasmids, 5 were congo red positive and 4 produced enterotoxin. Therefore, two B1 0:5 Lis Xz strains would be potentially virulent. All strains were susceptible to piperacillin, mezlocillin, cefuroxime, cefotaxime, amikacin, kanamycin, sisomicin, phosphomycin , chloramphenicol, trimethoprim-sulfamethoxazole and pipemidic acid. Ampicillin and sulfisoxazole proved to be less efficient.

Animals↗
PubMed1990

Biodegradation of azo and heterocyclic dyes by Phanerochaete chrysosporium.

Biodegradation of Orange II, Tropaeolin O, Congo Red, and Azure B in cultures of the white rot fungus, Phanerochaete chrysosporium, was demonstrated by decolarization of the culture medium, the extent of which was determined by monitoring the decrease in absorbance at or near the wavelength maximum for each dye. Metabolite formation was also monitored. Decolorization of these dyes was most extensive in ligninolytic cultures, but substantial decolorization also occurred in nonligninolytic cultures. Incubation with crude lignin peroxidase resulted in decolorization of Azure B, Orange II, and Tropaeolin O but not Congo Red, indicating that lignin peroxidase is not required in the initial step of Congo Red degradation.

Azo Compounds↗
PubMed1999

99mTc-MAMA-chrysamine G, a probe for beta-amyloid protein of Alzheimer's disease.

Chrysamine G (CG), an analogue of Congo red, is known to bind in vitro to the beta-amyloid protein (Abeta 10-43) and to homogenates of several regions of the brain of Alzheimer's disease (AD) patients. We synthesised a conjugate of 2-(acetamido)-CG with a bis-S-trityl protected monoamide-monoaminedithiol (MAMA-Tr(2)) tetraligand, which was efficiently deprotected and labelled with a 75% yield with technetium-99m, to obtain (99m)Tc-MAMA-CG. In mice, (99m)Tc-MAMA-CG was cleared mainly by the hepatobiliary system, resulting in a fast blood clearance. Brain uptake of (99m)Tc-MAMA-CG was low. Co-injection with the blood pool tracer iodine-125 human serum albumin ((125)I-HSA) demonstrated a brain/blood activity ratio for (99m)Tc-MAMA-CG that was significantly higher than that for (125)I-HSA (t test for dependent samples, P<0.02), indicating the ability of (99m)Tc-MAMA-CG to cross the blood-brain barrier. In vitro autoradiography demonstrated pronounced binding of (99m)Tc-MAMA-CG to beta-amyloid deposits in autopsy sections of the parietal and occipital cortex of an AD patient as compared with controls. Adding 10 microM Congo red during incubation displaced the binding of (99m)Tc-MAMA-CG. Congo red staining and autoradiography identified the same lesions. (99m)Tc-MAMA-CG seems to bind selectively to beta-amyloid deposition in human brain parenchyma and blood vessels in vitro and thus might be a lead compound for further development of a useful tracer agent for the in vivo diagnosis of Alzheimer's disease.

Adult↗
PubMed1986

Characterization of different amyloids with immunological techniques.

We studied 71 cases of amyloidosis from the autopsy material of our institute. 17 cases were secondary amyloidosis of which 7 had initially been diagnosed as primary amyloidosis; all cases reacted positively with an anti-substance A antibody; 13 showed a suppression and 4 a strong reduction of the Congo red staining following tissue incubation in KMnO4. 25 cases were identified as primary amyloidosis of which 7 had initially not been recognized as such. In 16 cases amyloid deposits reacted positively with antibodies specific for the light chains of the immunoglobulins (3 X kappa, 13 X lambda). A monoclonal plasmacytic cell proliferation in the bone marrow was seen in 14 cases. In all cases deposits were KMnO4 resistant, but 1 case showed a slight reduction of staining intensity. 27 cases were cardio-vascular (senile) amyloidosis; in 20 cases at least 3 organs showed deposits; 12 cases had deposits in 5 and more organs. 2 cases were heredofamilial amyloidosis. In those 29 cases deposits reacted positively with an anti-prealbumin antibody, but were negative for AA and the light chains of the immunoglobulins; the Congo red staining remained strong in all cases when previously incubated in KMnO4. KMnO4-Congo red staining and antisera specific for AA, L-chains and prealbumin proved of value for classification of amyloidosis and for its organ distribution.

Adult↗
PubMed1987

Demonstration and classification of amyloidosis in needle biopsies of the kidneys, with special reference to amyloidosis of the AA-type.

To examine whether sequence-specific antibodies directed against serum amyloid A were useful in the demonstration and classification of amyloidosis, needle biopsy specimens from the kidneys of 152 cases with renal disorders were investigated using the avidin-biotin-peroxidase complex technique of immunohistochemistry. A distinct immunoreactivity of protein AA was seen in biopsies from all 42 individuals who were clinically classified as having the AA-type of amyloidosis. The stained areas coincided with deposits stained by Congo red. Four of these cases demonstrated immunoreactivity of both protein AA and light immunoglobulin chains and all biopsies except one showed immunoreactivity for the amyloid P-component. After treatment with potassium permanganate, the amyloid deposits in the biopsies of all 42 cases lost their affinity for Congo red. Ten patients with clinical and laboratory findings compatible with the AL-type of amyloidosis were also investigated. All their biopsies demonstrated Congophilic amyloid deposits but none of them showed any immunoreactivity of protein AA. Amyloid deposits of lambda light immunoglobulin chains-but not kappa-were demonstrated in biopsies from four patients. The amyloid P-component was found in biopsies from six individuals and positive Congo red staining after treatment with potassium permanganate was seen in biopsies from four of the cases. Biopsies of 100 patients suffering from non-amyloid renal disorders were also examined. None of them displayed any immunoreactive deposits of protein AA. The investigation shows that amyloid deposits of the AA-type can be identified in needle biopsies when sequence-specific antibodies against serum amyloid A are used in the avidin-biotin-peroxidase complex technique. Both the diagnostic sensitivity (42 of 42) and specificity (110 of 110) of the assay were optimal (1.0). The method was found to be superior to other investigated techniques and useful for classifying amyloidosis in formalin-fixed renal biopsies.

Amyloidosis↗
PubMedDate not supplied

Genotypic and phenotypic characterization of potential virulence of intestinal avian Escherichia coli strains isolated in Algeria.

In order to characterize potential pathogenic Escherichia coli strains isolated from diarrheic hens and chickens originating from intensive battery rearing in North Algeria, the presence of a large range of virulence factors and markers was studied in 50 strains by DNA-DNA hybridization on colonies and phenotypic tests. The sequences we focused on were those coding for adhesins F5, F41, F17, Pap, Afa, and Sfa; intimin Eae; and toxins STa, STb, LT1, Stx1, Stx2, CNF1, and CNF2. The phenotypes explored were the colicins, aerobactin, hemolysins, and hemagglutinin production and serum resistance. The genotypic and phenotypic tests enabled us to categorize the isolates into two distinct groups: those with a potential to invade the host (27 strains were serum resistant and/or produced aerobactin), among which three strains were also potentially diarrheagenic, one strain was LT1 + F17+ Afa+ Pap+ (enterotoxigenic E. coli) and the two others were Stx1 (verotoxigenic E. coli). Twenty-three strains were colicinogenic, including 19 strains producing colicin V. This latter factor was also detected in isolates negative for the other virulence factors. On the basis of the type of erythrocytes agglutinated, we established 14 mannose-resistant hemagglutination patterns among the 37 strains tested, including 22 serum-resistant and/or aerobactin producing strains and 15 strains negative for these two characters. None of the strains produced alpha hemolysin, whereas two strains produced beta hemolysin and enterohemolysin, respectively. Congo red fixation was observed in 25 strains. No relationship could be detected between Congo red fixation and the presence of other virulence markers, such as serum resistance and aerobactin production. This study shows that among isolates originating from the feces of diarrheic chickens, the proportion of potentially diarrheagenic E. coli strains is low.

Adhesins, Escherichia coli↗
PubMed2005

Hsp20, a novel alpha-crystallin, prevents Abeta fibril formation and toxicity.

Beta-amyloid (Abeta) is a major protein component of senile plaques in Alzheimer's disease, and is neurotoxic when aggregated. The size of aggregated Abeta responsible for the observed neurotoxicity and the mechanism of aggregation are still under investigation; however, prevention of Abeta aggregation still holds promise as a means to reduce Abeta neurotoxicity. In research presented here, we show that Hsp20, a novel alpha-crystallin isolated from the bovine erythrocyte parasite Babesia bovis, was able to prevent aggregation of denatured alcohol dehydrogenase when the two proteins are present at near equimolar levels. We then examined the ability of Hsp20 produced as two different fusion proteins to prevent Abeta amyloid formation as indicated by Congo Red binding; we found that not only was Hsp20 able to dramatically reduce Congo Red binding, but it was able to do so at molar ratios of Hsp20 to Abeta of 1 to 1000. Electron microscopy confirmed that Hsp20 does prevent Abeta fibril formation. Hsp20 was also able to significantly reduce Abeta toxicity to both SH-SY5Y and PC12 neuronal cells at similar molar ratios. At high concentrations of Hsp20, the protein no longer displays its aggregation inhibition and toxicity attenuation properties. Size exclusion chromatography indicated that Hsp20 was active at low concentrations in which dimer was present. Loss of activity at high concentrations was associated with the presence of higher oligomers of Hsp20. This work could contribute to the development of a novel aggregation inhibitor for prevention of Abeta toxicity.

Alcohol Dehydrogenase↗
PubMed2006

Narrow-spectrum staining pattern of Pityrosporum.

BACKGROUND: Broad-spectrum fungal stains are used to detect fungal organisms, but narrow-spectrum stains can assist in fungal differential diagnosis. These stains include mucicarmine and Fontana-Masson (FM) for Cryptococcus, Alcian Blue for Cryptococcus and Blastomyces, Congo Red for Blastomyces and Coccidioides, and Ziehl-Neelsen for some examples of Blastomyces and Histoplasma. Pityrosporum is increasingly being recognized as a pathogen capable of significant cutaneous and systemic infections, but the narrow-spectrum staining pattern of Pityrosporum has not yet been systematically studied and reported. METHODS: Paraffin-embedded archival tissue from 10 skin biopsies containing Pityrosporum was stained with Alcian Blue, Congo Red, Ziehl-Neelsen acid-fast stain, and FM stain. In addition to the 60-min staining time, a modified FM stain with 15-, 30-, and 45-min staining times was also performed. RESULTS: All cases stained positive with Alcian Blue, Congo Red, and FM stains and negative with the Ziehl-Neelsen stain. The modified FM stain with the 15-min staining time showed significant staining in more than 50% of the cases. DISCUSSION: The narrow-spectrum staining pattern of Pityrosporum distinguishes it from Cryptococcus, Blastomyces, Candida, Histoplasma, and Coccidioides.

Biopsy↗
PubMed2000

Renal amyloidosis following tuberculosis.

Amyloidosis, either primary or secondary, may be defined as a group of chronic infiltrative disorders that have in common a beta-pleated sheet configuration on X-ray diffraction examination, a fine fibrillar nonbranching appearance on electron microscopy and an apple-green birefringence when examined under polarised light after staining with Congo-red. Renal amyloidosis is a rare entity in the pediatric age group and is almost always secondary in nature, related to chronic infections and inflammatory conditions. It occurs 2-7 years after a chronic inflammatory process; however an onset as early as 9 months of life is known. The diagnosis of amyloidosis is suspected on the basis of clinical features and is established by obtaining an appropriate tissue biopsy and demonstrating amyloid with appropriate stains. All the tissues obtained must be stained with Congo-red stain which is the singlemost useful diagnostic test to define amyloidosis. In order to differentiate the primary from secondary variety, the deposits may be treated with potassium permanganate before Congo-red staining. In secondary amyloidosis, the green birefringence seen under polarized light is abolished. Therapeutic approaches include specific measures to reduce the amyloid deposition and general measures to relieve symptoms related to involvement of specific organs. The prognosis in renal amyloidosis is relatively poor, with a median survival of 9-13 months in primary amyloidosis complicated by renal involvement, and more than 50 months in secondary amyloidosis. We have reported a case of secondary amyloidosis following tuberculosis and have discussed the clinical features, diagnosis and management of amyloidosis.

Amyloidosis↗
PubMed1988

Primary pulmonary amyloidosis with multiple nodules.

A 61-year old asymptomatic woman had a five-year history of pulmonary nodular lesions on routine radiographs. She underwent open lung biopsy, which revealed nodular lesions in the lungs and thickened pleura. Histological examination showed amyloid deposits in the pulmonary parenchyma and adjacent pleura. Congo Red staining of the specimen demonstrated green birefringence under polarized light. This affinity for Congo Red dye remained after potassium permanganate treatment, suggesting primary amyloidosis. Multiple nodular amyloidosis of the lungs should be included in the differential diagnosis of multiple pulmonary nodules.

Amyloidosis↗