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PubMed1976

Clinical significance of Congo red test.

Clinical significance of Congo red test was studied, especially on its relation to the liver function and amyloidosis. No significant relationship was observed between Congo red test and Indocyanin green test in cases of various liver diseases except liver cirrhosis. Histological studies also revealed that there were no pathologic features specifically affecting Congo red index (CRI), even though CRI in cases of various liver diseases tended to be increased as compared with other diseases. As a cause of increased CRI which was seen most remarkably in cases of liver cirrhosis, obstructive change of the liver blood flow followed by the hepatic tissue damage is suspected. The concept that Congo red test is a kind of the hepatic excretory function test does not have, from our data, enough evidence. The present study confirmed our previous data on the fate of Congo red injected intravenously, which indicated that this test is one of the best tests available for RES function and this test is related mainly to Kupffer's cell rather than to the so-called hepatic excretory function. There were no cases which showed notable decrease of CRI in experimental amyloidosis and in clinical amyloidosis, and it can be said that Congo red test is not the best test for the diagnosis of amyloidosis.

Acute Disease↗
PubMedDate not supplied

[Approach to sexuality in an AIDS context in Congo].

The pandemic due to the human immunodeficiency virus (HIV) is extensive in Sub-Saharan Africa and especially in Congo. Congo is a small country on the Atlantic coast and characterized by plentiful equatorial forests and low population density (essentially urban). In Congo, there is a high prevalence of HIV. The social and economic consequences of AIDS add to those of a recent civil war in 1997. There were fratricidal confrontations before and after this period. These confrontations have led to a massive exodus of the inhabitants of the capital, Brazzaville, to the forests and neighbouring cities, essentially towards Pointe-Noire. Pointe-Noire, chief place of the region of Kouilou, in the South of the country, is the second city of Congo and the economic Capital. It is undoubtedly for this reason that it has been globally saved. In this context, a sanitary policy of prevention of sexual risky behavior can appear as a challenge. While it supposes a better knowledge of the sexual activity of the young people, it cannot be dissociated from the analysis of the other factors. These factors can be of socio-economic political or cultural order. Thus the influence of cultural variables in the field of sexuality is certainly preponderant in African countries, where sexuality is taboo. Sexuality is a private matter (personal intimacy and the couple), but concerns also the family (in the sense of membership in an extended domestic group or in a system of relationship) in its aspects related to procreation and to the social field (power, alliances). Such individual behaviour can be lived as a questioning of the social order. In this article, the authors question the place of sexuality in Congo, particularly based on the work of anthropologists [2, 6, 7, 9]. Research in the field of sexuality at adolescence is rather recent in France and investigations that have been done in Congo these last ten years do not exist. Meetings and exchanges in 1998 with high-school pupils and schoolboys and girls of Pointe-Noire, have shown that they had a high level of knowledge (about contamination by HIV). On the other hand, this has also been associated with a number of beliefs, which are higher than in France: relating to the possibilities of interpersonal contagion by saliva (by kissing), food. but also a contagion by mosquito bites. Some of these pupils (essentially boys) have asked us about the greater risk of contagion when the male sexual partner presents an irritation or a wound in the penis. This recurring question seemingly concerns a point of knowledge. However a more attentive analysis lets us think that there could be various interpretations. First of all, if the penis is healthy, the risk is low, nearly absent. The concern about a friction or about a wound in the penis could be associated with the concept of forbidden sexual positions (similar to animal positions). Proscriptions are explained by their traumatic character for the feminine device and because they are able to induce an infertility or dystocia (difficult) childbirth. Other beliefs have connected the origin of AIDS with prohibited sexual practices, committed by foreigners, who passed on them secondarily to the natives of the country. They are clearly blamed in their contributions to the decline of customs and the corruption of tradition. However this unfavourable evolution is not longer only their privilege. Sexual superactivity and "sexual wandering" are also concerned. It is dialectic of the pure and the impure. The rejection or the stigmatisation of foreign values can allow the group to find its led astray identity. Condoms are well known by Congolese pupils, but there is mistrust of their use, notably for the "elders", guarantor for the moral order. This mistrust is probably connected with the beliefs of risks of infertility, infection or weakening of the virile force. Condoms are mechanical barriers, made by foreigners, to protect native people from foreign troubles, which foreigners generate. The investigation of chains of significant from the primary couple "nature/artificial (synthetic)" can establish a bait of understanding. The contraceptive action of condoms is a problem. Reproduction remains family business. Moreover, the place of the "morality", the official speech of condemnation from the Roman Catholic Church and the ambivalent positioning of certain Congolese religious congregations does not encourage condom use. Finally, one should not neglect their cost compared to the standard of living. The religious faith is a source of comfort for many Congolese. AIDS can be lived as a spiritual probation that certain traditional healers would have foreseen. Certain ideologies can be a source of intolerance for people who transgress "ways of life" (alcohol, tobacco, anal sexual intercourse.). The religious congregations have invaded the public space. The medical world and the political institutions cannot ignore them any more. (ABSTRACT TRUNCATED)

Acquired Immunodeficiency Syndrome↗
PubMed2001

Correlation between Congo red binding and contact haemolysin production in Shigella species.

Haemolytic strains of Shigella dysenteriae type 1, Shigella flexneri, Shigella boydii and Shigella sonnei cultured on Congo red agar produced pigmented colonies (Pcr+) whereas nonhaemolytic strains produced white colonies and did not bind Congo red (Pcr-). S. flexneri-1 haemolysin negative mutant (lacking plasmid) of haemolysin positive prototroph also did not bind Congo red and produced nonpigmented colonies. Among the twelve strains of Shigella included in this study, the characteristics of Congo red binding, plasmid profile and haemolytic activity appeared to be correlated. Congo red binding occurred comparatively more by haemolysin-producing strains. Congo red binding can be used as a quick and reliable method for virulence traits of pathogens, including haemolysin activity.

Bacterial Adhesion↗
PubMed2003

The structural abnormality of myeloma immunoglobulins tested by Congo red binding.

BACKGROUND: Frequently observed structural deviations of myeloma-derived immunoglobulins affect polypeptide chain packing and domain stability, enhancing their tendency to aggregate, with all the clinical consequences. Congo red complexation with myeloma immunoglobulins is proposed in this work as a general test to disclose the instability of these proteins. The large ribbon-like supramolecular ligands of Congo red form complexes with proteins by adhesion to beta-conformation polypeptide chains, if allowed to make contact with their backbone interfaces. This can occur in the case of myeloma-derived immunoglobulins with deficient polypeptide chain packing. MATERIAL/METHODS: Specially adapted two-dimensional agarose electrophoresis of serum proteins, which allows the transient contact of Congo red and serum proteins during migration, was used to reveal the presence of protein components amenable to ligand penetration and binding. The combination of electrophoresis and Congo red binding to proteins permits the removal of loosely attached dye and evaluation of the effective complexation properties of the immunoglobulin fraction directly in the serum. RESULTS: Comparative studies of dye complexation with two L chains having different reactivities with Congo red confirmed that dye binding depended on protein instability in the conditions used. Myeloma proteins revealed different binding capabilities in the test used here. CONCLUSIONS: The complexes formed by the supramolecular dye Congo red with myeloma immunoglobulins differ in stability. Those of high stability indicate the abnormal protein structure thought to produce clinical symptoms. This work proposes an easy technique to differentiate the stability of complexes.

Amino Acid Sequence↗
PubMed2003

Protein distorsion-derived mechanism of signal discrimination in monocytes revealed using Congo red to stain activated cells.

The supramolecular dye Congo red was used to check whether monocyte activation may be mediated by a torsion-dependent mechanism preventing transduction of weak random signals in cell contacts in a way corresponding to the discrimination mechanism found in complement fixation by immune complexes. Tight cell-cell contacts generating torsional effects may be expected to produce alteration of receptor structure, making them accessible for binding of supramolecular dyes. In this study, Congo red was used to observe the binding accessibility of (1) monocytes (human) induced by contact with cancer cells (HCV29T, human), (2) monocytes (mouse) stimulated by interaction with heat-aggregated IgG and (3) monocytes (mouse) activated by rosetting in the presence of an SRBC-anti-SRBC system. Microscopic studies confirmed the activation of monocytes manifested by their clustering and Congo red binding, but only tightly clustered cells appeared to attach the dye on the surface. Usually not the whole cell surface is found to be engaged in dye complexation. Staining occurs predominantly on the interfaces of reacting cells, making probable the suggestion that cell adhesion receptors are involved in dye binding. The cells in the central areas of tight clusters undergo accelerated death. In the presence of Congo red they are easily recognized as intensely fluorescent. The characteristic localization of dead cells in the central area of clusters indicates that death is not random but results from cell activation. The role of Congo red in this process remains to be clarified. The staining characteristics of monocytes after application of Congo red probably discloses the initial step in signal transduction generated by torsional movements in receptor proteins.

Animals↗
PubMed2003

A hospital survey of the clinical features of diabetes in Congo.

The occurrence of diabetes mellitus is increasing throughout the world, both in industrialised nations and in developing countries. While this disease is not a leading cause of death in developing country populations, it must nevertheless be considered for its social and economic impact. This study examines the clinical and epidemiological situation of diabetes mellitus in the city of Kinshasa, Democratic Republic of Congo, as based on data from two city hospitals: Saint Joseph's Hospital (SJH) and the Centre Hospitalier Monkole (CHM), two urban health facilities typical of those developing countries. The results show that diabetes is a real public health problem in Congo. Average blood glucose levels were above 300 mg/dl in 44.4% of patients at SJH and 41.5% at CHM, and hypertension (> or = 140/90 mmHg) was reported in 35.8% of patients at SJH and 20% at CHM. The management of diabetes and, in particular, its complications is suffering because of some cultural influences but mainly economic ones. In fact, incidence of disease complications is closely linked to the financial status of patients and facilities. SJH, which serves mainly the low-income community, has a greater incidence of severe diabetes-associated complications than CHM, which treats patients with a higher mean income level. SJH hospitalised patients had a 24.7% incidence of diabetic foot with 3 amputations as compared to only a 10% incidence and no amputations for CHM hospitalised patients. At SJH, 17.3% of patients died during the study, while at CHM none died. Overall, differences in the prevalence of complications between SJH and CHM patients were found not to be significant. For the large majority of Congo population, education on diabetes is not available, and due to the failure of the national health system, access to treatment is impossible. Furthermore, because most diabetic people in Congo go untreated, the mortality rate for the disease is high. Congo would greatly benefit from a national diabetes program in order to give all diabetic patients in Congo access to good and consistent medical care.

Adult↗
PubMed1978

Demonstration of amyloid with Mesitol WLS-Congo Red: application of a textile auxiliary to histochemistry.

Previous histochemical investigations demonstrated similarities in the binding of Congo Red and other direct cotton dyes by amyloid and cellulose. It seemed therefore of interest to determine whether or not the cellulose-like reactivity of amyloid extends also to dye solutions containing an anionic reserving agent. These reagents are used in the dyeing of wool-cellulose (Halbwolle) fabrics to prevent binding of direct cotton dyes by proteins. Mesitol WLS-Congo Red solutions stained amyloid selectively; other tissue structures, except some hyaline deposits in arterioles, remained unstained. The cause of this non-specific reaction could not be determined with certainty. Therefore, the alkaline Congo Red method is recommended for histochemical identification of amyloid. However, the Mesitol WLS-Congo Red technic was very useful for demonstration of amyloid after prolonged storage of tissues in formalin; amyloid in such material showed little or no reactivity with the alkaline Congo Red or the Sirius dye methods. This pilot study indicates that anionic reserving agents can be effectively employed under conditions of histochemical technics.

Amyloid↗
PubMed2006

Systemic administration of Congo red does not improve motor or cognitive function in R6/2 mice.

Huntington's disease (HD) is a progressive neurodegenerative disorder for which there is no treatment. Prior to the onset of symptoms, abnormal protein aggregates (inclusions) are found in neurons in humans and R6/2 mice. It has been suggested that the progression of HD can be slowed or prevented by disruption of the aggregation process. In agreement with this, it has been reported that systemic treatment of R6/2 mice with Congo red caused a reduction in numbers of striatal inclusions and an improvement in motor symptoms and survival [Sanchez, I., Mahlke, C., Yuan, J., 2003. Pivotal role of oligomerization in expanded polyglutamine neurodegenerative disorders. Nature 421, 373-379]. Here we attempted to replicate this study. We extended the experiment to include measurement of the effects of Congo red on cognitive function in R6/2 mice. Congo red treatment failed to ameliorate either motor or cognitive deficits in R6/2 mice. We suggest that this is due to the inability of Congo red to cross the blood-brain barrier. Since it does not improve the behavioural deterioration that is a key feature of HD, Congo red is unlikely to be useful as a therapy for HD.

Animals↗
PubMed2005

Virulence differences between monkeypox virus isolates from West Africa and the Congo basin.

Studies indicate that West African and Congo basin isolates of monkeypox virus (MPXV) are genetically distinct. Here, we show Congo basin MPXV-ZAI-V79 is more virulent for cynomolgus monkeys as compared to presumed West African MPXV-COP-58. This finding may explain the lack of case-fatalities in the U.S. 2003 monkeypox outbreak, which was caused by a West African virus. Virulence differences between West African and Congo basin MPXV are further supported by epidemiological analyses that observed a similar prevalence of antibodies in non-vaccinated humans in both regions, while >90% of reported cases occurred in the Congo basin, and no fatal cases were observed outside of this region. To determine the basis for this difference in virulence, we sequenced the genomes of one human West African isolate, and two presumed West African isolates and compared the sequences to Congo basin MPXV-ZAI-96-I-16. The analysis identified D10L, D14L, B10R, B14R, and B19R as possible virulence genes, with D14L (ortholog of vaccinia complement protein) as a leading candidate.

Africa, Western↗
PubMed2000

Congophilicity (Congo red affinity) of different beta2-microglobulin conformations characterized by dye affinity capillary electrophoresis.

The amyloidogenic protein beta-microglobulin was characterized by affinity capillary electrophoresis (CE). CE could separate conformational variants of beta2-microglobulin and with the amyloid-specific dye Congo red as a buffer additive it was possible to measure different Congo red-affinities of native and abnormally folded beta2-microglobulin. We find that native beta2-microglobulin has an intermediate affinity for Congo red at pH 7.3 and that binding involves electrostatic interactions. The conformational variant of beta2-microglobulin that appears in acetonitrile solutions binds Congo red more strongly. Affinity CE using Congo red as a buffer additive is a new, simple, fast, and quantitative micromethod for the characterization of soluble conformational intermediates of amyloidogenic proteins.

Coloring Agents↗
PubMed2003

Diagnosis of renal amyloidosis using Congo red fluorescence.

Early diagnosis and classification of amyloid deposition and differentiation from other glomerular fibrillar deposits relies on routine Congo red (CR) histochemistry. Congo red fluorescence (CRF) is an alternative method based on examination of the CR-stained section by ultraviolet (UV) light. The aim of this study is to investigate the usefulness of CRF, especially when applied to frozen kidney sections. Congo red fluorescence was applied to sections of frozen kidney biopsies prospectively and to paraffin sections retrospectively. The findings of CRF were compared to CR staining in bright light. Prospectively, 15 cases of amyloidosis were diagnosed on frozen sections and identical CR staining was found in all of the paraffin-stained sections. There were no false positives or negatives. Retrospectively, 146 renal biopsies previously stained with CR were re-evaluated with CRF. Eighty-seven CR positive cases were confirmed by CRF, and one new case was identified. Congo red fluorescence is simple to perform and more pronounced, therefore easier to evaluate than CR in bright light. Congo red, when combined with immunohistochemistry, is still visible under UV whereas CR is masked in bright light. Although not widely used, the CRF method for detecting amyloid is simple to use with a high specificity and sensitivity, and may be applied successfully to frozen sections.

Amyloid↗
PubMed1987

Congo red uptake by motile Aeromonas species.

Virulence of several species of enteropathogenic bacteria has been correlated with the ability of isolates to take up the dye Congo red. To determine whether Congo red uptake might be a useful marker for virulence of motile Aeromonas species, we examined 50 strains of diverse clinical origin on a medium containing 50 micrograms of Congo red per ml. All of the strains took up the dye to various degrees. For most strains, uptake was greatest at 37 degrees C and least at 22 degrees C. Production of acetyl methyl carbinol (Voges-Proskauer test) or lysine decarboxylase has been reported by some investigators to be a virulence marker for Aeromonas species. Congo red uptake did not correlate with either acetyl methyl carbinol or lysine decarboxylase production in our study. These data suggest that Congo red uptake may not be a useful marker for virulence of motile Aeromonas species.

Aeromonas↗
PubMed1988

Congo red binding of elastin in aortic smooth muscle cell cultures.

These studies demonstrate that the strong binding capacity of elastin for Congo red can be used to advantage in aortic smooth muscle cell cultures. A fibrous elastin network fluoresces when Congo red is added. Congo red does not alter accumulation of elastin or of total protein, even when the cells are grown in the presence of the dye for long periods of time, indicating that it is not toxic. Porcine pancreatic elastase was used to solubilize elastin in these cultures, to determine the molar ratio of Congo red to elastin, thus making it possible to estimate the amount of elastin solubilized when the cultures are injured. Congo red binding to elastin will be useful in studying elastin accumulation and/or degradation in vitro and in vivo.

Animals↗
PubMed2004

Growth, Congo Red agar colony morphotypes and antibiotic susceptibility testing of Mycobacterium avium subspecies paratuberculosis.

OBJECTIVE: Mycobacterium avium subspecies (subsp.) paratuberculosis (MAP) is the causative agent of Johne's disease in ruminants and has been associated with Crohn's disease in humans. We sought to test growth rates and susceptibilities of various strains of MAP in two available growth media. DESIGN: Paired comparison design. METHODS: Using the BACTEC macrobroth radiometric growth system and Congo Red-staining agar media, we determined inherent differences in growth characteristics of three bovine and two human strains of MAP and compared susceptibility results obtained in each growth system. RESULTS: Significant differences were observed in growth rate as well as mycobactin J dependence between strains and between a laboratory-adapted isolate of the same strain in the macrobroth system. Similarly, colonial morphology and Congo Red staining on agar media were observed. Two strains, one human and one bovine, demonstrated a 100% rough transparent colony with white coloration on Congo Red agar, while one bovine isolate exclusively grew as a smooth opaque colony with red coloration on Congo Red agar. The remaining strains exhibited mixtures of these two colonial morphotypes on agar media. Comparative susceptibility results between the BACTEC radiometric macrobroth method and the agar proportionality method showed good correlation for most antibiotics/inhibitors tested. However, erratic or poor growth in the macrobroth system prevented minimal inhibitory concentration determinations for two bovine strains by this method. CONCLUSION: This study demonstrates the variability in the colonial morphology of MAP on Congo Red agar as well as the correlation of antibiotic susceptibility results between the BACTEC macro broth method and the agar proportionality method. This study also emphasizes the need for the development of improved, standardized culture and susceptibility test methods for MAP.

Agar↗
PubMedDate not supplied

Congo red binding test in enteroinvasive and nonpathogenic Escherichia coli strains.

Out of 6 variants the appropriate media to perform Congo red binding test for enteroinvasive E. coli strains were established (trypto-soy agar Eiken, T.S.A.--Cantacuzino Institute and B.T.S.D.). 12 E. coli strains belonging to enteroinvasive O-serogroups formed on Congo red agar red-coloured, non-coloured colonies or both; cultures from 59 red colonies and 61 white colonies were inoculated in guinea pig eyes. The correlation between positive Congo red binding test and positive Sereny test was 91% (out of 59 red colonies, 47 evoked keratoconjunctivitis in both infected eyes and 7 in only one eye). The negative Congo red binding test corresponds (98.4%) to the failure to induce illness in the guinea pigs' eye (only one out of 61 Crb = colonies was Sereny positive, evoking keratoconjunctivitis in only one of the two infected eyes of a guinea pig). Comparing in vivo lack of pathogenicity in 44 E. coli strains isolated from human normal intestinal flora and negative Congo red binding test, a correlation of 72.73% on B.T.S.D. and 65.91% on T.S.A. medium was found. Developing an appropriate method based on Crb test about 70% of the nonpathogenic E. coli colonies could be eliminated from the laborious agglutination with enteroinvasive O-serogroups E. coli antisera.

Animals↗
PubMedDate not supplied

Congo red binding by Escherichia coli isolates from chickens.

An attempt was made to use a recently reported special Congo red medium to determine the pathogenicity of Escherichia coli isolates obtained from chickens. The inclusion of bile salts in the Congo red medium as described in previous reports by others was found in the current experiments to cause the production of red colonies from almost all E. coli cultures tested, including known Congo red-negative control cultures. Cultures of E. coli, regardless of their pathogenic history, rarely produced red colonies on the Congo red medium without added bile salts. Numerous isolates of other bacterial genera were examined and found to produce red colonies on the Congo red medium with or without added bile salts.

Animals↗
PubMed2000

[Evaluation of the possible technological uses of some dioscoreas tubers: name congo (Dioscorea bulbifera) and mapuey (Dioscorea trifida)].

A comparison between the chemical composition and physical characteristics of ñame congo (Dioscorea bulbifera) and mapuey (Dioscorea trifida) white and purple varieties, was made. The tubers were evaluated for their physical attributes (morphology, size and weight). The chemical analysis was done according to AOAC methods (1990) and the pasting properties of the flours were evaluated using the Brabender Viscoamilograph. The mapuey tubers have an elongated shape, with one end wider while ñame congo presents a rounded shape. The results of the chemical analysis show that mapuey tubers have more proteins content (p < or = 0.05) than either purple mapuey tubers purple or ñame congo tubers. The flours overall viscosity, measured at the same concentration, was higher for white mapuey varieties. The gelatinization temperature range was similar among the flours. The negative breakdown datas suggest that the flours viscosity increases during the gelatinization process of all flours. Neither suspensions showed a viscosity peak. Set-back and consistency were lower in the ñame congo flour. The absence of a viscosity peak and the high temperature stability of the ñame congo flour make it an ideal ingredient for instant soup mixes. The flours high viscosity level developed by white and purple mapuey varieties should make it a suitable sauces thickener.

Flour↗
PubMed1984

Differential Congo red staining: the effects of pH, non-aqueous solvents and the substrate.

Congo red is an acid-base indicator dye. In free solution the colour and absorption characteristics of Congo red depend not only on the pH but are also governed by the nature of the solvent environment. In tissue sections stained by Congo red, alteration of the pH and the use of non-aqueous solvents can effect differential colouring of the tissue components. Stained sections of unmodified and chemically substituted celluloses show that differential red or blue coloration reflects the acidic or basic character of the substrate. In stained tissue sections, secondary protein structure and porosity of the substrate may also influence their colour. The effect of non-aqueous solvents is probably to modify the ionization state of the dye-substrate complex, thus altering the colour of the Congo red. Such solvents may also change the aggregation or solvation states of the dye, with consequent modification in the colour of tissue components.

Congo Red↗