Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “LIBERIA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1986

In vivo and in vitro susceptibility of Plasmodium falciparum to sulphadoxine/pyrimethamine in Liberia, West Africa.

The in vivo response of Plasmodium falciparum to standard treatment with sulphadoxine/pyrimethamine was studied in 19 hospital patients from Yekepa town with hypoendemic malaria and in 28 children, two to nine years old, living in a village with holoendemic malaria. In vitro tests were performed on eight isolates. In the hospital patients all parasites cleared with mean clearance time of 2.2 (range one to three) days and no recrudescence occurred during a 28-day follow-up period. In the village children, despite a high sporozoite inoculation rate, recurrent parasitaemias were only recorded after 28 days, suggesting a rather long-lasting prophylactic effect against reinfection by the drug combination. In vitro, inhibition of parasite multiplication was achieved by 3 X 10(-7) M sulphadoxine and 3.8 X 10(-9) M pyrimethamine.

Adolescent↗
PubMed2003

Ultrastructural morphologic description of the wild rice species Oryza latifolia (Poaceae) in Costa Rica.

The wild rice species Oryza latifolia is endemic to Tropical America, allotetraploid and has a CCDD genome type. It belongs to the officinalis group of the genus Oryza. This species is widely distributed throughout the lowlands of Costa Rica and it is found on different life zones, having great morphologic diversity. The purpose of this research is to perform a morphologic description of O. latifolia samples of three Costa Rican localities (Carara, Liberia and Cañas) and to see if the phenotypic diversity of the species is reflected at the ultra-structure level. Structures such as the leaf blade, ligule, auricles and spikelet were analyzed. Leaf blade morphology of the specimens from the three localities is characterized by the presence of diamond-shaped stomata with papillae, zipper-like rows of silica cells; a variety of evenly distributed epicuticular wax papillae and bulky prickle trichomes. The central vein of the leaf blade from the Cañas populations is glabrous, while those from Carara and Liberia have abundant papillae. There are also differences among the borders of the leaf blade between these locations. Cañas and Liberia present alternating large and small prickle trichomes ca. 81 and 150 microns, while Carara exhibits even sized prickle trichomes of ca. 93 microns. Auricles from Cañas are rectangular and present long trichomes along the surface ca. 1.5 mm, while those of Liberia and Carara wrap the culm and exhibit trichomes only in the borders. The ligule from the plants of Carara has an acute distal tip, while that of Cañas and Liberia is blunt. The Liberia spikelet has large lignified spines while Cañas and Carara show flexible trichomes.

Costa Rica↗
PubMed1997

Onchocera volvulus: characterization of a highly immunogenic Gln-rich protein.

A pool of sera from individuals classified as putatively immune (PI) to Onchocerca volvulus infection was employed in the screening of a fourth-stage larval cDNA expression library. A highly immunogenic clone, encoding the Ov 53/80 protein, was identified. The full length cDNA of clone 4.21 contained 2527 nucleotides encoding 769 amino acids of which 100 are glutamine residues (13%). Antibodies raised against recombinant protein encoded by a partial cDNA sequence (clone 73-k) recognized a 53 and 80 kDa protein in O. volvulus larval and adult parasite extracts, respectively. The antibodies localized the native protein in the cuticle, hypodermis, secretory vesicles and in granules of the glandular esophagus of larvae and in the hypodermis and the cuticle of adult worms. The recombinant 73-k polypeptide (r73) was recognized by 90-100% of sera from PI and infected individuals from Liberia, but only by 67% of similar groups from Ecuador. r73 specific IgG2 and IgG3 levels in the PI from Liberia and Ecuador, respectively, were significantly lower than in the infected, whereas the r73 specific IgG1/IgG3 or IgG1/IgG2 in the PI and the infected individuals from Liberia or Ecuador, respectively, were similar. The IgG4 specific antibody response in the PI from Liberia and Ecuador were lower than in the infected. The T-cell proliferative responses to r73 in infected individuals from Cameroon were found to be inversely correlated with their levels of microfilariae.

Amino Acid Sequence↗
PubMed1989

Screening of African sera stored for more than 17 years for HIV antibodies by site-directed serology.

Antibodies to Human Immunodeficiency Virus type 1 (HIV-1) and type 2 (HIV-2) were investigated, using site-directed enzyme immunoassay (ELISA), in 320 specimens obtained from three remote, African tribes during 1969-1971. Using HIV-1 E34/E32 ELISA and HIV-2 149 ELISA, assay were conducted on 101 serum specimens from the Korekore tribe of Zimbabwe, 93 specimens from the Mano tribe of Liberia, and 126 specimens from the Turkana tribe of Kenya; specimens which tested positive in ELISA were further tested by radioimmunoprecipitation assay (RIPA) and Western blot (WB). Two serum specimens from the Mano tribe of Liberia gave OD 492 nm values greater than 0.2 in HIV E34/E32 ELISA in all three runs. These two specimens reacted with HIV-1 envelope proteins gp160 and gp120 and the internal protein p24 in RIPA and WB; however, the reactivity was uncostant. All other serum specimens were negative for HIV-1 and HIV-2 antibodies. Site directed ELISA serology for HIV-1 and HIV-2 gave very low rates of false positive reactivity. Thus, reaction with HIV-1 antigen was identified in two persons of one tribe in Liberia in 1971, but HIV-2 antibodies were not detected in this tribe; HIV-1 and HIV-2 antibodies were absent during the late 1960's and early 1970's from two African tribes resident in Zimbabwe and Kenya.

AIDS Serodiagnosis↗
PubMed2003

Ethical codes in humanitarian emergencies: from practice to research?

Notable strides have been made in recent years to develop codes of conduct for humanitarian intervention in conflicts on the part of international NGOs and UN organisations. Yet engagement by the academic and broader research communities with humanitarian crises and ongoing complex political emergencies remains relatively ad hoc and unregulated beyond the basic ethical guidelines and norms developed within universities for research in general, and within the governing and representative bodies of particular academic disciplines. This paper draws on a case study of research on humanitarian assistance to Liberia during that country's civil war from 1989 to 1996. The difficulties faced by humanitarian agencies in Liberia led to the development of two key sets of ethical guidelines for humanitarian intervention: the Joint Policy of Operations (JPO) and Principles and Policies of Humanitarian Operations (PPHO). This paper seeks to address what lessons, if any, these ethical guidelines, together with different experiences of conducting research in war-torn Liberia, can provide in terms of the role of academic researchers--and research itself--in humanitarian crises.

Altruism↗
PubMed1990

Tropical ataxic neuropathy in Liberians.

Tropical ataxic neuropathy (TAN) is reported for the first time from Liberia. It occurred in 2 women, within the child-bearing age from the same family in Sinoe County, Liberia. The family's diet consisted of rice and cassava derivatives. The diagnosis of this condition was made on clinical grounds. The patients had the classical features of this syndrome: bilateral primary optic atrophy, bilateral perceptive deafness, myelopathy and peripheral neuropathy. In Nigeria, chronic cyanide intoxication from cassava derivatives is the etiologic factor. In Liberia the cause is unknown but considering the similarities between the cases reported here and those reported from Nigeria, the etiologic factor operating in both countries may be the same.

Adolescent↗
PubMed1972

Isolation and properties of the causal agent of a new variola-like disease (monkeypox) in man.

The causal agent of a case of disease in man occurring in the Democratic Republic of the Congo with a similar clinical picture to smallpox was isolated and studied. The agent was identified as monkeypox virus. A comparative study of the isolated strain (Congo-8) and of viruses isolated from similar cases of illness in Liberia (Liberia-1 and Liberia-2 strains) and Sierra Leone (V-70 1 266 strain) showed that they were identical. A number of local species of monkeys and apes were examined serologically in the Congo region to determine the probability of human infection with monkeypox virus. It was confirmed that the animals had had contact with an agent of the poxvirus group. In 2 of the 7 sera examined, antibodies of the variola-vaccinia group of poxviruses were discovered (virus-neutralizing antibodies, precipitins, and antihaemagglutinins). In a chimpanzee, antihaemagglutinins were found in a titre of 1: 1 280, and in the same animal a variola-like virus was isolated from the kidneys. In the course of the investigation, it was shown conclusively that monkeypox virus and the strains under investigation could be distinguished from o dinary variola and vaccinia viruses on the basis of their behaviour in pig embryo kidney continuous cell line culture.

Animals↗
PubMed2000

Genetic diversity among Lassa virus strains.

The arenavirus Lassa virus causes Lassa fever, a viral hemorrhagic fever that is endemic in the countries of Nigeria, Sierra Leone, Liberia, and Guinea and perhaps elsewhere in West Africa. To determine the degree of genetic diversity among Lassa virus strains, partial nucleoprotein (NP) gene sequences were obtained from 54 strains and analyzed. Phylogenetic analyses showed that Lassa viruses comprise four lineages, three of which are found in Nigeria and the fourth in Guinea, Liberia, and Sierra Leone. Overall strain variation in the partial NP gene sequence was found to be as high as 27% at the nucleotide level and 15% at the amino acid level. Genetic distance among Lassa strains was found to correlate with geographic distance rather than time, and no evidence of a "molecular clock" was found. A method for amplifying and cloning full-length arenavirus S RNAs was developed and used to obtain the complete NP and glycoprotein gene (GP1 and GP2) sequences for two representative Nigerian strains of Lassa virus. Comparison of full-length gene sequences for four Lassa virus strains representing the four lineages showed that the NP gene (up to 23.8% nucleotide difference and 12.0% amino acid difference) is more variable than the glycoprotein genes. Although the evolutionary order of descent within Lassa virus strains was not completely resolved, the phylogenetic analyses of full-length NP, GP1, and GP2 gene sequences suggested that Nigerian strains of Lassa virus were ancestral to strains from Guinea, Liberia, and Sierra Leone. Compared to the New World arenaviruses, Lassa and the other Old World arenaviruses have either undergone a shorter period of diverisification or are evolving at a slower rate. This study represents the first large-scale examination of Lassa virus genetic variation.

Africa, Western↗
PubMed1998

Violence against women during the Liberian civil conflict.

CONTEXT: Civilians were often the casualties of fighting during the recent Liberian civil conflict. Liberian health care workers played a crucial role in documenting violence against women by soldiers and fighters during the war. OBJECTIVE: To document women's experiences of violence, including rape and sexual coercion, from a soldier or fighter during 5 years of the Liberian civil war from 1989 through 1994. DESIGN: Interview and survey. SETTING: High schools, markets, displaced persons camps, and urban communities in Monrovia, Liberia, in 1994. PARTICIPANTS: A random sample of 205 women and girls between the ages of 15 and 70 years (88% participation rate). RESULTS: One hundred (49%) of 205 participants reported experiencing at least 1 act of physical or sexual violence by a soldier or fighter. Survey participants reported being beaten, tied up, or detained in a room under armed guard (17%); strip-searched 1 or more times (32%); and raped, subjected to attempted rape, or sexually coerced (15%). Women who were accused of belonging to a particular ethnic group or fighting faction or who were forced to cook for a soldier or fighter were at increased risk for physical and sexual violence. Of the 106 women and girls accused of belonging to an ethnic group or faction, 65 (61%) reported that they were beaten, locked up, strip-searched, or subjected to attempted rape, compared with 27 (27%) of the 99 women who were not accused (P< or =.02, .07, .001, and .06, respectively). Women and girls who were forced to cook for a soldier or fighter were more likely to report experiencing rape, attempted rape, or sexual coercion than those who were not forced to cook (55% vs 10%; P< or =.001, .06, and .001, respectively). Young women (those younger than 25 years) were more likely than women 25 years or older to report experiencing attempted rape and sexual coercion (18% vs 4%, P=.02 and .04, respectively). CONCLUSIONS: This collaborative research allowed Liberian women to document wartime violence against women in their own communities and to develop a unique program to address violence against women in Liberia.

Adolescent↗
PubMed1986

Onchocerca volvulus: enzyme polymorphism in relation to the differentiation of forest and savannah strains of this parasite.

Isozyme analysis was carried out on Onchocerca volvulus worms collected from Liberia, Ivory Coast, Burkina Faso and Sudan to see whether this technique could detect differences between forest and savannah populations of this parasite. A total of 243 forest and 189 savannah individual female worms were electrophoresed and stained for seven enzymes. Four showed some polymorphism, LDH, MDH, PGM and MPI and the other three, GAPDH, PEP and GPI were invariant. Statistical analysis of the results showed that the relative proportions of genotypes from within the different countries conformed to Hardy-Weinberg expectations. Pairwise comparisons of allele frequencies between countries showed that populations from Liberia and Ivory Coast had a very similar composition; there was some divergence between all the other pairs of populations and the genetic distance was calculated to summarize the degree of divergence. The number of loci examined was small and the genetic distances were within the range expected for separate geographical populations of the same species. The usefulness of this technique in worm identification is discussed.

Alleles↗
PubMed2004

The relationships between the burden of adult parasites, host age and the microfilarial density in human onchocerciasis.

We investigate the relationship between the microfilarial density in the skin and the burden of adult female Onchocerca volvulus by analysing pre-control nodulectomy data which allow for a direct approach, independent of exposure. The data of 169 patients in Burkina Faso and 182 patients in Liberia represent savannah and forest onchocerciasis in West Africa, respectively. Whereas in Burkina Faso, a saturating relationship between microfilarial density and worm burden suggests the operation of density-dependent processes within human hosts, the Liberian data show a linear relationship implying no density dependence. The differences may derive from differences between both parasite strains, i.e. the savannah or the forest strain of O. volvulus. Consistently for both parasite strains and independent of the worm burden, the microfilarial density increases with host age emphasising the concept of the acquisition of immunological tolerance. In male hosts in Liberia, the microfilarial density increases stronger with the worm burden than in female hosts, whereas such sex-specific differences cannot be found in Burkina Faso. In the methodological part of this investigation, we suggest the beta-distribution to be most appropriate for describing variability in microfilarial densities and we present an approach to consider the uncertainty in the adult parasite burden which cannot be determined precisely in helminth infections. Implications of density dependence are discussed with respect to immunological processes in the human host and with respect to the success of control programs. The relationships described show that regulatory processes between the parasite and the human host are multi-dimensional, operating within a high degree of biological variability.

Age Factors↗
PubMed2006

Developing capacity to protect human research subjects in a post-conflict, resource-constrained setting: procedures and prospects.

The capacity-building strategy used by a US-based research organisation, the Pacific Institute for Research and Evaluation (PIRE), to strengthen the system for the protection of human research subjects and the infrastructure of its international collaborating partner, the University of Liberia, are discussed. To conduct the much-needed biomedical and social science-based research-related activities in the future, this partnership is expected by PIRE to gradually evolve over time to strengthen the capacity of the local investigators and administrators of the University of Liberia. Accordingly, a unique opportunity to share technology and resources with a post-conflict, resource-constrained country is created by this partnership. This capacity-building model to strengthen the protection of human subjects in research can also be replicated in similar resource-constrained international settings and, accordingly, our experiences and limitations are shared in this paper.

Culture↗
PubMed2002

[Workshop of military reconstructive surgery in Conakry May 1999: example of civilian-military cooperation in responding to medical-surgical crisis emergencies].

During the period from 1998 to 1999, civil wars broke out in number of west African countries including Liberia, Sierra Leone, and Guinea Bissau. Due to the situation in surrounding countries, Guinea Conakry was forced to accept nearly 650000 refugees whose presence represented a major risk for the socio-political stability of the country. International organizations and NGOs condemned the atrocities inflicted on civilian populations by the children serving as soldiers in the RUF rebels organizations of Sierra Leone and Liberia. These attacks included murders, gang rapes, abduction of children and young people, and mutilation of extremities of people of all ages ranging from infants to elderly. Treatment of mutilation victims requires the availability of facilities for surgical treatment and prosthetic fitting in Guinea Conakry. The humanitarian action division of the French Foreign Affairs Department and the NGO Handicap International decided to provide specialized training in the management of mutilation injuries to surgical groups in hospitals of Guinea and Sierra Leone. The program consisted in a workshop on reconstructive surgery for war-related injuries to allow optimal prosthetic fitting for reinsertion of mutilation victims into society.

Adolescent↗
PubMed1959

Effect of pyrimethamine upon sporogony and pre-erythrocytic schizogony of Laverania falciparum.

Studies have been conducted in Liberia on the effect of pyrimethamine on the sporogony and, for the first time, on the pre-erythrocytic schizogony of Laverania falciparum. From the results reported here it is concluded that it may reasonably be assumed that a mass monthly regimen of pyrimethamine in Liberia could afford protection to the individual and to the mosquito and thus to the population at large, provided that resistance to pyrimethamine does not intervene.Pyrimethamine in single doses of 25 mg or 50 mg administered to gametocyte carriers was able to render gametocytes of L. falciparum uninfective to A. gambiae for periods up to 28 days after administration.Mosquitos feeding upon a malaria-free pyrimethamine-treated subject before or after feeding upon a non-treated gametocyte carrier became infected and sporozoites appeared in the salivary glands.Pyrimethamine administered in 12.5-mg doses 13 days before, 6 days before and 2 days after sporozoite infection or administered in 25-mg doses 35 days and 7 days before sporozoite infection disallowed the development of the pre-erythrocytic schizonts of L. falciparum in the livers of two chimpanzees.

Antimalarials↗