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PubMed2001

The earliest cases of human immunodeficiency virus type 1 group M in Congo-Kinshasa, Rwanda and Burundi and the origin of acquired immune deficiency syndrome.

The early cases of acquired immune deficiency syndrome and human immunodeficiency virus type 1 (HIV-1) infection in the 1960s and 1970s in Congo-Kinshasa (Zaire), Rwanda and Burundi are reviewed. These countries appear to be the source of the HIV-1 group M epidemic, which then spread outwards to neighbouring Tanzania and Uganda in the east, and Congo-Brazzaville in the west. Further spread to Haiti and onwards to the USA can be explained by the hundreds of single men from Haiti who participated in the UNESCO educational programme in the Congo between 1960 and 1975.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Epidemiology of drug-resistant malaria in Republic of Congo: using molecular evidence for monitoring antimalarial drug resistance combined with assessment of antimalarial drug use.

In Congo, urgent efforts are needed to help with the revision of the national antimalarial drug policy. Despite its high resistance level, chloroquine (CQ) is still extensively used as the first-line treatment for uncomplicated Plasmodium falciparum malaria. The study was conducted in children under 5 years with uncomplicated malaria in Pointe-Noire and Brazzaville, the two largest cities that contain approximately 60% of the population of Congo. We investigated by polymerized chain reaction and sequencing methods the frequency distribution of molecular markers for antimalarial drug resistance, including mutations in P. falciparum chloroquine resistance transporter (pfcrt) gene associated with CQ resistance and mutations in dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes conferring resistance to sulphadoxine/pyrimethamine (SP) among pre-treatment P. falciparum isolates, as well as assessing antimalarial drug use in the community. pfcrt (K76T) mutation was present in most isolates (96.4%, n = 138) and high frequency (69.2%, n = 133) of triple-mutant dhfr-S108N, N51I, C59R was observed. The quintuple mutant (dhfr-S108N, N51I, C59R and dhps-A437G or S436A, K540E) considered as molecular marker for SP treatment failure was not found because dhps-K540E mutation was absent in isolates tested; this is a clear evidence for the excellent efficacy of SP that we previously described in the same population. The complete absence of the dhps-K540E mutation is a deterrent component for using this molecular marker as an early warning tool for SP resistance testing in that population. Poor compliance issues related to the antimalarial drug use including inappropriate manufacturing practices reported in this study require intensive attention and should be taken into account when implementing drug policy change. If Congo changes its treatment policy from CQ to SP monotherapy, this will not last long. The strategy of combining SP with other affordable and effective antimalarial drugs such as the artemisinin derivatives to improve efficacy and to delay the development of parasite resistance is essential.

Antimalarials↗

PubMed1969

Congo red-agar plating medium for detecting pigmentation in Pasteurella pestis.

Ability to detect pigmented and nonpigmented Pasteurella pestis is essential in plague research, and is currently dependent on use of the synthetic hemin-agar of Jackson and Burrows. We have devised a new differential medium for this purpose, containing Congo red dye and common, commercially available laboratory media. The ease and simplicity of preparation make the Congo red-agar a practical routine laboratory tool in plague research. These findings, possibly indicating a common binding site for hematin and Congo red, should be useful in efforts to determine the chemical nature of a bacterial component associated with high virulence in P. pestis.

Agar↗

PubMed1983

Differentiation between virulent and avirulent Yersinia enterocolitica isolates by using Congo red agar.

Cultivation of clinical isolates of Yersinia enterocolitica of diverse geographical origin on a medium containing 5 micrograms of Congo red per ml disclosed two colony types. These were designated CR+ and CR- according to their ability to bind Congo red. CR+ strains bore plasmids of between 40 and 50 megadaltons and were positive in several tests of Y. enterocolitica virulence, including autoagglutination, reduced growth on magnesium oxalate agar, resistance to the bactericidal effect of serum, and lethality for iron-overloaded mice. CR- strains were plasmidless and were negative in all these assays. The Congo red reaction provides a simple and efficient means of screening Y. enterocolitica for virulence and is the best available method for identifying individual plasmid-bearing colonies.

Agglutination Tests↗

PubMed1995

High-sensitivity diagnosis of AA amyloidosis using Congo red and immunohistochemistry detects missed amyloid deposits.

Biopsy diagnosis of early amyloid-A (AA) amyloidosis has often been difficult. Examination of 57 consecutive biopsy specimens from 42 patients with inflammatory pediatric diseases permitted comparison of the precision of biopsy amyloid diagnosis in six different laboratories (labs), which applied the following methods: Congo red alone (four unspecialized labs combined as Lab 1), Congo red and electron microscopy (Lab 2), or Congo red and immunohistochemistry using monoclonal antibodies (Lab 3). Lab 3 reexamined the diagnoses made by Lab 1 and Lab 2. Of the 42 patients, 17 patients with 32 biopsies were selected for this study based on the presence of amyloid in at least one biopsy. Whereas massive or no amyloid was concordantly recognized by all labs in 18 biopsies from nine patients, discordance was demonstrated in 14 biopsies from eight patients. Comparison of Labs 1-3 revealed amyloid in 12 rectal and 18 renal biopsies evaluated by Lab 3, whereas Lab 2 missed amyloid in two of 18 renal biopsies and Lab 1 missed amyloid in 11 of 12 rectal biopsies. Most amyloid was missed when only minute amounts of amyloid were present. Had our technique (Lab 3) been available at the time of biopsy, amyloid could have been diagnosed years earlier, thereby sparing the patient further biopsies and allowing initiation of earlier treatment before organ damage could occur.

Adolescent↗

PubMed2005

Acetylcholinesterase-amyloid-beta-peptide interaction: effect of Congo Red and the role of the Wnt pathway.

The cholinergic system impairment observed in Alzheimer's disease (AD) patients leads to the cognitive, global and behavioral dysfunction commonly associated with dementia. The only treatment for AD has been the use of inhibitors of acetylcholinesterase (AChE) (E.C. 3.1.1.7), which is one of the several proteins associated with amyloid plaque deposits. Recently, novel dual inhibitors of AChE have been developed that target both the active site of the enzyme as well as the peripheral anionic site (PAS). Such inhibitors prevent the aggregation of amyloid-beta-peptide (Abeta) into Alzheimer's fibrils. The incorporation of AChE, as a "chaperone" into amyloid aggregates results in the modification of the biochemical properties of the enzyme, including: sensitivity to low pH, inhibition at high substrate concentration, and increases of the Abeta neurotoxicity. Congo Red dye stabilizes the Abeta monomer, is able to inhibit oligomerization, and inhibits the binding of AChE to Abeta. However no effect of Congo Red on the binding of AChE to the Abeta preformed fibrils was observed. These studies suggest that different interactions between Abeta soluble-AChE and Abeta fibrils-AChE take place during the association between them. Docking studies were performed to evaluate the binding of Congo Red to Abeta in order to identify putative binding sites in the Abeta monomer that might interact with AChE. The binding site involves a region between residues 12 and 16. Finally, recent studies are consistent with the idea that a attenuating beta-catenin loss of function of Wnt signaling components may play a role in the progression of neurodegenerative disease, such as AD, providing a connection between AChE-Abeta neurotoxicity and the Wnt signal transduction pathway.

Acetylcholinesterase↗

PubMed2000

Amyloid peptide channels: blockade by zinc and inhibition by Congo red (amyloid channel block).

Amyloid peptides are the major constituents of amyloid deposits in various amyloid diseases including Alzheimer's disease, type II diabetes mellitus, prion diseases and others. The hallmark of amyloid is the binding of the dye, Congo red, which creates characteristic staining due to the dye's ability to bind the beta sheet aggregates referred to as amyloid. Previous reports have demonstrated that several cytotoxic, amyloidogenic peptides can form ion channels in planar phospholipid bilayer membranes and have suggested that these channels may represent the pathogenic mechanism of cell and tissue destruction in amyloid disease. Furthermore, zinc and Congo red can ameliorate or prevent the pathogenic effect of certain amyloidpeptides. We report here that zinc at micromolar concentrations caused a reversible blockade of islet amyloid polypeptide (IAPP, amylin) and PrP 106-126 channels whereas calcium and magnesium did not. Congo red completely inhibited channel formation if preincubated with amyloid peptides, but had no effect on IAPP or PrP 106-126 channels once formed. These results suggest a requirement for aggregation for the formation of amyloid peptide channels and are consistent with the "channel hypothesis" of amyloid disease. They also suggest potential avenues for ameliorative therapy of these illnesses.

Amyloid↗

PubMed1999

Histological and epidemiological profile of oral cancer in Congo (Zaire).

From the files of the Department of Pathology at Kinshasa University Hospital, D.R. Congo, we have studied the histological and epidemiological profile of oral cancer in Congo. The relative frequency of oral cancer in Congo is 2.1%. The palate is the most common site (28.8%) and the squamous cell carcinoma the most frequent histological type (57.6%). People between 50 and 59 years old (27%) (Means: 48.39 +/- 15.43 years) and females (M/F = 0.47/1 are more affected).

Adolescent↗

PubMed2001

Progress toward poliomyelitis eradication--Angola, Democratic Republic of Congo, Ethiopia, and Nigeria, January 2000-July 2001.

In 1988, the World Health Assembly, governing body of the World Health Organization (WHO), resolved to eradicate poliomyelitis globally by 2000. In the African Region (AFR), WHO member countries began to implement polio eradication strategies in 1995. Although rapid progress has occurred in much of eastern and southern Africa, wild poliovirus transmission continues to occur in four priority countries: Angola, Democratic Republic of Congo (DR Congo), Ethiopia, and Nigeria. This report summarizes progress toward polio eradication in Angola, DR Congo, Ethiopia, and Nigeria during January 2000-July 2001, and indicates that 11 of 12 cases of wild poliovirus in AFR were identified in these priority countries during January-July 2001.

Angola↗

PubMed1992

[Current recrudescence of human trypanosomiasis in the Sangha focus (basin) in the Congo].

In the Congo the Sangha focus of sleeping sickness caused more than 500,000 deaths in the early 20th century. Despite many years of quiescence many new cases have been detected since the early eighties. In 1987 an investigation found 43 infected patients within 5 villages (during the same year, 74 cases were detected from both investigation and passive detection). In December 1989 our further investigation found 96 new documented cases (115 for the whole year). The prevalence is increasing and the proportion of early stage in comparison with later stage is decreasing. The age diagram resembles that of the early 20th century. Despite the fact that the survey in 1989, extracted twice as many patients as in 1987 passive detection detected 99 infected patients in 1990, three times as many cases as in 1988, and places the "Sangha focus" in IId place in the Congo, after the "Bouenza focus". As only river transport is available to have access to that focus, the Congo will be faced with considerable difficulties in the future.

Animals↗

PubMed2006

Congo red interaction with alpha-proteins.

The ability of Congo red to form complexes with alpha-proteins, human growth hormone and human interferon-alpha2b, was found by absorption difference spectroscopy. A human growth hormone-Congo red complex was isolated by gel-permeation chromatography, and its visible absorption spectrum was registered in comparison to free dye. The ability of Congo red to induce dimerization of human growth hormone was demonstrated using chemical cross-linking agents 1,3,5-triacryloyl-hexahydro-s-triazine and ethylene glycol bis(succinimidylsuccinate).

Biophysics↗

PubMedDate not supplied

[Effect of Congo red on the motility of the bacterium Azospirillum brasilense].

In semiliquid laboratory media, the bacterium Azospirillum brasilense migrates with the formation of swarming rings. It is demonstrated that adsorption of the sulfonated azodye Congo Red confers on A. brasilense the ability to consistently spread in a semiliquid agar and form microcolonies. Spontaneous variants of A. brasilense with rapid swarming are described, as well as variants that swarm in the presence of Congo Red. It is assumed that at least two types of compounds are formed, which are (a) necessary for swarming and/or spreading with the formation of microcolonies and (b) capable of interacting with Congo Red.

Azospirillum brasilense↗

PubMedDate not supplied

The congo red stain revisited.

The Congo red stain has undergone several modifications since it was first used by Bennhold in 1922 in order to increase the specificity for staining amyloid. Most of the laboratories in the United States use the method of Puchtler which uses alkaline Congo red solution. Some of the variables associated with the procedure were investigated by us. Our results showed the following: (1) amyloid showed green birefringence at all levels between 4 to 12 mu thick sections with better visualization of small deposits with increased thickness. Best results were obtained with 8 mu thick sections; (2) omission of the pretreatment with alkaline alcoholic solution of sodium chloride (NaCl) did not affect the sensitivity of the method; (3) the use of polar mounting media had no effect on amyloid and collagen birefringence; (4) 50 percent saturation of the Congo red staining solution with NaCl caused strong staining of collagen, elastic fibers and eosinophilic granules. In addition, collagen showed green birefringence and dichroism and its differentiation from amyloid became difficult; and (5) using the staining solution fully saturated with NaCl, no positive staining was seen with tissues other than amyloid. Collagen and elastic fibers showed red fluorescence which was of less intensity than amyloid. It is our conclusion that the method of Puchtler for detecting amyloid gives better results if the staining solution is fully saturated with NaCl. The pretreatment step may be deleted without compromising the quality of staining. Improved staining of amyloid enhances the specificity of green birefringence, dichroism, and red fluorescence.

Amyloid↗

PubMed1989

Modified sham feeding and Congo red test in determining completeness of vagotomy.

Gastric acid response to modified sham feeding was evaluated in 14 patients with duodenal ulcer prior to vagotomy and in 18 patients after vagotomy. Nine patients in the latter group had recurrent ulcer, suggesting inadequate vagotomy. Based on values in the 32 tests (14 pre and 18 postoperative), cut-off levels of six secretory indices were selected to provide a specificity of 1.00 for the presence of ulcer. When applied separately to the 18 postoperative patients and to the 13 patients who underwent the endoscopic congo red test, observed volume of 75 ml/h and peak volume of 90 ml/h following sham feeding gave specificity, sensitivity and efficiency of 1.00 each in determining inadequate vagotomy. The endoscopic congo red test done in 13 post-vagotomy cases showed a sensitivity of 1.00, and high specificity (0.89) and efficiency (0.92). Measurement of crude gastric juice response to modified sham feeding is a convenient bedside test to confirm inadequate vagotomy. The endoscopic congo red test is also useful, especially as a screening test, and has the added advantage that it can be used intra-operatively.

Adult↗

PubMed1982

Evaluation of vagotomy by the Hollander-Congo red test.

In the present study, the completeness of vagotomy in patients who underwent truncal and highly selective vagotomy is evaluated, comparing them with control groups of normal persons and patients with a duodenal ulcer. The evaluation was made by the Hollander test, followed by the endoscopic Congo red test, using the same hypoglycemic stimulus. Gastric acid production was higher in the patients with duodenal ulcer, followed by the normal persons. Lower acidity levels were obtained for patients with truncal vagotomy than for patients with highly selective vagotomy. During the Congo red test, we noted that the patients with truncal or highly selective vagotomy had small black spots in the gastric mucosa, except those having a recurrent ulcer, denoting incomplete vagotomy. Nevertheless, when we observed the appearance of the gastric mucosa, we noted a similar aspect for those having had a vagotomy and for normal persons. This appearance was completely different from the patients with a duodenal ulcer. We concluded that truncal vagotomy greatly reduces the level of gastric acid production, while highly selective vagotomy does so to a lesser extent. The endoscopic aspect of these patients during the Congo red test was similar to that for normal persons.

Adult↗

PubMed1997

The use of congo red as a lyotropic liquid crystal to carry stains in a model immunotargeting system--microscopic studies.

The lyotropic liquid crystal dye-Congo Red was used as a carrier in a model immunotargeting system constructed from sheep red blood cells (SRBC) representing the antigen target and rabbit IgG anti-SRBC as the specific driving immunoglobulin. Rhodamine B and Hemin stains were chosen as example chemicals carried to the target. The carried stains were introduced to the micellar organization of Congo Red by intercalation. Preserving its supramolecular organization, Congo Red binds spontaneously and selectively to antibodies that have altered structure extorted by interaction with the antigen in the immune complex. The functionality of the studied immunotargeting model was verified by fluorescence and electron microscopy. The results indicate that the supramolecular nature of protein ligands offers new ligation capabilities possibly useful for carrying stains or drugs in immune-oriented systems.

Animals↗

PubMed2006

A GIS-based assessment on the vulnerability and future extent of the tropical forests of the Congo Basin.

This paper examines the vulnerability of the Congo Basin's forests through a GIS platform, taking into consideration the variables of population growth, road density, logging concession, and forest fragmentation. The assessment indicates that the forests will continue to shrink towards the interior over the next 50 years. Current contiguous forests will fragment into three large blocks, including one on the west side of the Congo River and two in the Democratic Republic of Congo, while a large number of small forest patches will retain in the periphery of the large blocks. The study shows that integrated GIS assessment of the driving forces of tropical deforestation can shed light on the future forest distribution and provide a tool to address the broader implications of social and economic development for tropical deforestation.

Africa, Central↗

PubMed1983

Congo Red Absorption by Rhizobium leguminosarum.

Congo red absorption is generally considered a contraindication of Rhizobium. However, R. leguminosarum takes up the dye on yeast extract-mannitol agar. The uptake of congo red varies among strains of R. leguminosarum, as shown elsewhere with strains of R. trifolii and R. meliloti. Congo red absorption does not distinguish rhizobia from other bacteria, but may be useful as a strain marker.

Journal Article↗