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Biomedical subjects

K C Kain

Publications and source records attributed to K C Kain.

At least 55 records · Page 3Linked to original sources
PubMed1999

Immunochromatographic strip-based detection of Entamoeba histolytica-E. dispar and Giardia lamblia coproantigen.

BIOSITE Triage was 68.3% sensitive and 100% specific for the detection of Entamoeba histolytica-E. dispar (n = 71) compared to Alexon-Trend's ProSpecT test (reference standard) using fresh-frozen stool. Neither test is able to distinguish E. histolytica from E. dispar. Triage was 83.3% sensitive and 100% specific compared to microscopy (formalin-ether concentrates and permanent stains) for the detection of Giardia lamblia.

Animals↗
PubMed1999

Evaluation of a rapid and inexpensive dipstick assay for the diagnosis of Plasmodium falciparum malaria.

Rapid, accurate and affordable methods are needed for the diagnosis of malaria. Reported here is an evaluation of a new immunochromatographic strip, the PATH Falciparum Malaria IC Strip, which is impregnated with an immobilized IgM monoclonal antibody that binds to the HRP-II antigen of Plasmodium falciparum. In contrast to other commercially available kits marketed for the rapid diagnosis of falciparum malaria, this kit should be affordable in the malaria-endemic world. Using microscopy and polymerase chain reaction (PCR)-based methods as reference standards, we compared two versions of the PATH test for the detection of P. falciparum infection in 200 febrile travellers. As determined by PCR and microscopy, 148 travellers had malaria, 50 of whom (33.8%) were infected with P. falciparum. Compared with PCR, the two versions of the PATH test had initial sensitivities of 90% and 88% and specificities of 97% and 96%, respectively, for the detection of falciparum malaria. When discrepant samples were retested blindly with a modified procedure (increased sample volume and longer washing step) the sensitivity and specificity of both kits improved to 96% and 99%, respectively. The two remaining false negatives occurred in samples with < 100 parasites per microliter of blood. The accuracy, simplicity and predicted low cost may make this test a useful diagnostic tool in malaria-endemic areas.

Antibodies, Monoclonal↗
PubMed1999

Skin lesions in returned travelers.

Skin problems are commonly encountered during and after travel. Because of increasing travel and tourism to remote and previously unvisited areas, it is likely that these and other dermatologic conditions will continue to be frequent problems observed in travelers. For the nondermatologist, recognition of many of the commonly encountered skin problems can be facilitated by following the lesion-oriented approach outlined in this article.

Humans↗
PubMed1998

The Plasmodium falciparum-CD36 interaction is modified by a single amino acid substitution in CD36.

CD36 is an 88-kD glycoprotein involved in the cytoadherence of Plasmodium falciparum-parasitized erythrocytes (PE) to endothelial cells. The molecular mechanisms involved in CD36-dependent cytoadherence were examined by expressing three CD36 homologues (human, murine, and rat) in COS-7 cells and observing their PE-binding characteristics over a pH range of 6.0 to 7.4 and following iodination of these receptors. PE binding to human CD36 was pH dependent, with peak binding at pH 6.8 to 7.0, and binding was unaffected by iodination. In contrast, PE adherence to murine and rat CD36 was insensitive to changes in pH, and iodination significantly reduced binding. We further show that the differences observed in the binding phenotype of human and rodent CD36 can be attributed to a single residue. Site-directed mutagenesis of the histidine at position 242 of human CD36 to tyrosine (found in rodent CD36) conferred the binding phenotype of rodent CD36 onto human CD36. Furthermore, substitution of the tyrosine at position 242 of rat CD36 for histidine conferred the binding phenotype of human CD36 onto rat CD36. These findings suggest that residue 242 is part of, or important to the conformation of, the PE-binding domain of CD36.

Amino Acid Sequence↗
PubMed1998

Malaria in travelers. Epidemiology, disease, and prevention.

The combination of increases in international travel and escalating drug resistance has resulted in a growing number of travelers contracting malaria. Preventing malaria-associated morbidity and mortality will require improved health information for travelers about the risk of malaria and appropriate preventive measures, improved recognition of infection by physicians, rapid and accurate laboratory diagnosis, and prompt initiation of effective therapy.

Antimalarials↗
PubMed1998

Effects of viral hemorrhagic fever inactivation methods on the performance of rapid diagnostic tests for Plasmodium falciparum.

Blood samples from patients with viral hemorrhagic fever (VHF) pose a serious risk to laboratory workers. Current contingency plans for VHF samples recommend the use of heat, gamma-irradiation, or Triton X-100 to inactivate samples before handling. Malaria is the most important alternative diagnosis to be excluded in cases of suspected VHF. Interpretation of malaria smears using samples inactivated with these methods is problematic because morphology is altered. The objective of this study was to assess the impact of different inactivation methods on the performance of rapid diagnostic tests for Plasmodium falciparum. Triton X-100 and gamma-irradiation of samples preserved detection. The impact of Triton X-100 inactivation was also "blindly" evaluated using 100 blood samples from febrile travelers. Triton X-100 inactivation of samples did not significantly affect the performance of these tests. This may represent a useful strategy for excluding the diagnosis of falciparum malaria in cases of suspected VHF.

Blood↗
PubMed1998

Imported malaria: prospective analysis of problems in diagnosis and management.

Imported malaria is an increasing problem in many countries. The objective of this study was to prospectively evaluate the diagnosis and treatment of imported malaria cases identified by active surveillance. Microscopic diagnosis at the community level was also compared to reference microscopic and blinded molecular diagnostic methods. Most travelers who acquire malaria had sought pretravel advice from a physician; however, only 11% used recommended chemoprophylaxis and only 17% used insect protection measures. The diagnosis of malaria was initially missed in 59% of cases. Community-based microscopic diagnosis provided incorrect species identification in 64% of cases. After presentation, the average delay before treatment was 7.6 days for falciparum malaria and 5.1 days for vivax malaria. Overall, 7.5% of Plasmodium falciparum-infected patients developed severe malaria, and in 11% of all cases therapy failed. Patients who present to a center without expertise in tropical medicine receive suboptimal treatment. Improvements in recognition, diagnosis, and treatment of malaria are essential to prevent morbidity and death among travelers.

Adolescent↗
PubMed1998

Chloroquine-resistant Plasmodium vivax in transmigration settlements of West Kalimantan, Indonesia.

Malariometric surveys were conducted during July 1996 in native Dayak villages and predominantly Javanese transmigration settlements in Ketapang district of West Kalimantan, Indonesia. Malaria prevalence ranged from 0.9% to 2.7% in Dayak villages and from 1% to 20% in the transmigration settlements. Plasmodium falciparum accounted for 67% of the cases among Dayaks but P. vivax was dominant among transmigrants, accounting for more than 72% of the infections. Chloroquine sensitivity/resistance was assessed by 28-day in vivo testing of uncomplicated malaria infections and measurement of chloroquine blood levels in cases where parasitemias reappeared within the 28-day test period. Resistance was based on the appearance of asexual parasites against chloroquine plus desethylchloroquine levels exceeding the minimally effective whole blood concentrations proposed for sensitive parasite strains (P. vivax, 100 ng/ml; P. falciparum, 200 ng/ml). All parasitemias cleared initially within four days of beginning supervised chloroquine therapy (25 mg base/kg over a 48-hr period), but asexual parasites reappeared within 28 days in 27 of 52 P. vivax and three of 12 P. falciparum cases. Chloroquine blood levels at the time of recurrent parasitemias revealed resistance in 12 of the 27 P. vivax cases and in one of the three P. falciparum cases. Genotypes of nine of the 12 recurrent P. vivax isolates matched with their primary isolates and ruled out reinfection. These findings establish the presence of chloroquine-resistant P. vivax on the island of Borneo. The pattern of malaria and the high frequency of chloroquine resistance by P. vivax at the West Kalimantan location may relate to demographic, ecologic, agricultural, and socioeconomic changes associated with transmigration.

Adolescent↗
PubMed1997

Fatal falciparum malaria in Canadian travellers.

The authors report 2 cases of severe falciparum malaria in Canadians that had fatal outcomes. In the first case a man presented to a local hospital shortly after returning from Africa, but a diagnosis of malaria was not considered. He was transferred to a secondary and then to a tertiary care facility, where he subsequently died. Intravenous quinidine therapy, the treatment of choice, was unavailable at all 3 hospitals. In the second case, a woman taking chloroquine prophylaxis while visiting Nigeria developed cerebral malaria and died. These cases illustrate critical management issues: appropriate advice on malaria prevention before departure; consideration of malaria in all febrile people returning from an endemic area; ready access to parenteral therapy for severe malaria in Canadian hospitals; and an increase in awareness of travel medicine among family physicians.

Africa↗
PubMed1997

Plasmodium vivax infections in U.S. Army troops: failure of primaquine to prevent relapse in studies from Somalia.

Different strains of Plasmodium vivax vary in their sensitivity to primaquine, the only drug that prevents relapses. Described are the clinical data and relapse pattern for 75 soldiers treated for vivax malaria since returning from Somalia. Following their initial attack of malaria, 60 of the 75 cases received a standard course of primaquine (15 mg base daily for 14 days). Twenty-six of the 60 soldiers subsequently relapsed for a failure rate of 43%. Eight soldiers had a second relapse following primaquine therapy after both the primary attack and first relapse. Three of these soldiers had received a higher dosage of primaquine (30 mg base daily for 14 days) after their second attack. The apparent ineffectiveness of primaquine therapy in preventing relapses suggests the presence of primaquine-resistant P. vivax strains in Somalia.

Adolescent↗
PubMed1997

Parasight F test compared with the polymerase chain reaction and microscopy for the diagnosis of Plasmodium falciparum malaria in travelers.

Imported malaria is an increasing problem worldwide. A rapid and accurate test for Plasmodium falciparum infection would facilitate the diagnosis of malaria in the returned traveler. The ParaSight F antigen capture assay (dipstick test) is a new diagnostic test for P. falciparum based on detection of circulating histidine-rich protein-2 antigen. We performed a blinded evaluation of this assay compared with microscopy and the polymerase chain reaction (PCR) for the detection of P. falciparum infection in 151 febrile travelers. Compared with the PCR, the dipstick test had a sensitivity of 88% and a specificity of 97%. The ability of the dipstick test to detect P. falciparum was similar with that of microscopy (88% versus 83%) since the species of Plasmodium in 14 of 133 malaria-infected patients could not be determined by microscopy due to low parasite numbers. The dipstick test was 40% sensitive for infections with < 50 parasites/microliter, 89% with 50-100 parasites/microliter, and > or = 93% with > 100 parasites/microliter. Circulating antigen was detectable in 68% of the patients seven days after initiation of treatment and in 27% at day 28. The dipstick test represents a simple and accurate test for the diagnosis of P. falciparum infection in the returned traveler.

Adolescent↗
PubMed1997

Distinguishing Plasmodium falciparum treatment failures from reinfections by restrictions fragment length polymorphism and polymerase chain reaction genotyping.

The inability to distinguish recrudescent Plasmodium falciparum infections (treatment failures) from reinfections (new infections) is an important impediment to the evaluation of antimalarial treatment regimens. Ten paired primary and recrudescent isolates collected near the Thai-Cambodian border were analyzed by restriction fragment length polymorphism (RFLP) and by polymerase chain reaction (PCR) genotyping of the genes encoding the following proteins: circumsporozite (CS) protein, erythrocyte binding antigen (EBA)-175, ring-infected erythrocyte surface antigen (RESA), merozoite surface protein-1 (MSP-1), and MSP-2. Both methods demonstrated that the fingerprint pattern of each recrudescent isolate was identical to or was contained within the pattern of the primary isolate. Each recrudescent isolate was unique when compared with the other nine primary isolates. Typing by PCR was more sensitive for the detection of multiclone infections and could be performed with small volumes of whole blood. The PCR genotyping could be a practical method for distinguishing a recrudescent from a new infection when treatment studies are conducted in areas with active malaria transmission.

Adolescent↗
PubMed1996

Single-strand conformational polymorphism analysis differentiates Plasmodium falciparum treatment failures from re-infections.

Paired primary and recrudescent Plasmodium falciparum isolates were collected from treatment failures identified during the course of antimalarial drug studies on the Thai-Cambodian border. Ten paired samples were subjected to PCR-restriction fragment length polymorphism (RFLP) and PCR-single-strand conformational polymorphism (PCR-SSCP) analysis of the MSP-2 gene. PCR-SSCP analysis of paired samples demonstrated that each recrudescent isolate was identical to, or a subpopulation of, its matched primary isolate and was distinct from all unrelated isolates. This method represents a field applicable method to distinguish re-infections from treatment failures when antimalarial drug studies are performed in malaria-endemic areas.

Animals↗