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K C Kain

Publications and source records attributed to K C Kain.

At least 91 records · Page 5Linked to original sources
PubMed1993

Response of Plasmodium vivax variants to chloroquine as determined by microscopy and quantitative polymerase chain reaction.

Genotypic heterogeneity in the repetitive portion of the circumsporozoite (CS) protein of Plasmodium vivax has been reported from many P. vivax-endemic areas. The objective of this study was to determine if the VK210 and VK247 CS variants of P. vivax differed in their clearance rates following chloroquine (CQ) therapy. One hundred seventy-one cases of P. vivax infection occurring in patients presenting to a research treatment center in Thailand were analyzed. Finger-prick blood samples were collected for microscopy and spotted onto filter paper at presentation and on each of five days of observation through supervised CQ therapy. A portion of the CS gene was amplified from filter paper samples by the polymerase chain reaction (PCR) and genotyped by oligoprobes specific for the VK210 and VK247 CS repeat regions. The mean time to clear parasitemia as determined by thick blood smear was significantly longer for pure VK210 infections (51 hr; 95% confidence interval [CI] 47.4-54, P = 0.006) and mixed infections (53 hr; 95% CI 49.2-56.7, P = 0.0009) as compared with VK247 infections (44 hr; 95% CI 39.8-47.9). Five patients matched for parasitemia, age, sex, and previous malaria experience were selected from each of the three genotype groups in the larger study for further analysis by quantitative PCR of P. vivax genotype-specific DNA during a treatment course. The mean time to clear parasite DNA, as determined by PCR, was significantly slower for VK210 parasites (65 hr; 95% CI 51-79) than for VK247 parasites (47 hr; 95% CI 30-63, P = 0.045).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Detection of Plasmodium falciparum by polymerase chain reaction in a field study.

Detection of Plasmodium falciparum by polymerase chain reaction (PCR) was evaluated in 33 P. falciparum-infected patients with two different amplification systems over 5-7 days of curative treatment. In the K1-14 system, a P. falciparum DNA fragment of 206 bp was detected, and in the circumsporozoite (CS) system, a fragment of 800 bp was detected. The K1-14 and CS systems identified 95% and 93%, respectively, of 103 microscopically identified specimens; both systems detected as few as 11 parasites/microliters among these specimens. Specimens from 20 smear- and history-negative controls were all negative by both PCR systems. The K1-14 and CS systems detected P. falciparum DNA in 53% and 20%, respectively, of blood films collected on the first day and 3% and 0 of the blood films collected on the fourth day after reversion to microscopic negative. The simultaneous use of two independent PCR systems to monitor patients during curative treatment of P. falciparum infections convincingly demonstrated that P. falciparum DNA was present transiently in the blood of infected patients at a time when the parasite could no longer be detected microscopically.

Animals↗
PubMed1992

Circumsporozoite genotyping of global isolates of Plasmodium vivax from dried blood specimens.

The prevalence and global distribution of two circumsporozoite (CS) genotypes of Plasmodium vivax (VK210 and VK247) were determined by genetic analysis of isolates from 234 malaria-infected patients. Whole blood specimens were collected on filter paper from patients infected with malaria in Thailand, Mexico, Papua New Guinea, Peru, Afghanistan (Pakistan), India, and western Africa and from 50 asymptomatic smear-negative controls. Following extraction of DNA from the filter paper samples, the CS gene was amplified by the polymerase chain reaction and genotyped by using oligoprobes specific for the VK210 and VK247 repeat epitopes. The sensitivity of genotyping from a single blood dot was 95.2%. The VK247 CS genotype was identified in the blood of patients from all seven study areas and was the predominant form present in samples from Thailand (83%) and Papua New Guinea (90%). In contrast, VK247 DNA was present in only 9% of isolates from Mexico. Individuals infected with both genotypes simultaneously were identified in all study areas except Mexico and were particularly common in Thailand (58%) and Papua New Guinea (60%). These findings indicate that the VK247 genotype of P. vivax is widely distributed but that its prevalence varies geographically. In addition, we conclude that use of samples of whole blood on filter paper is a practical and sensitive method for determining the genotypes of large numbers of malaria isolates collected in field settings.

Amino Acid Sequence↗
PubMed1992

Serologic and genetic characterization of Plasmodium vivax from whole blood-impregnated filter paper discs.

The presence in the New World of a variant strain of Plasmodium vivax (VK247) containing a unique circumsporozoite (CS) repeat domain was determined by the detection of antibodies to the variant CS protein and by genetic analysis of the CS gene from field isolates. Whole blood specimens were collected on filter paper from patients infected with P. vivax in Mexico and Peru. Plasmodium vivax DNA was eluted from filter paper samples and the CS gene was amplified by the polymerase chain reaction (PCR) and analyzed for the presence of VK247 or VK210 DNA by oligoprobe hybridization. Sera eluted from a companion filter paper sample were screened for antibodies reactive with the predominant and variant repeat peptides by enzyme-linked immunosorbent assays (ELISA) and with sporozoites by the immunofluorescent antibody (IFA) test. All 24 patients were positive by PCR and oligoprobe hybridization for either VK210 (16 of 24), VK247 (3 of 24), or both (5 of 24). Mixed infections were common (5 of 7) in Peru, but were not observed in the Mexican isolates (0 of 17). All three VK247 infections from Mexico occurred in residents of the foothills above Tapachula (P = 0.02). Of patients with smear-positive P. vivax infection, 42% (10 of 24) had detectable antibodies eluted from dried blood dots that were reactive with the CS protein by IFA or ELISA. These findings establish the widespread distribution of the P. vivax variant CS protein in the New World and indicate that dried blood filter paper samples represent a valuable source of material for the serologic and molecular analysis of plasmodial infections.

Animals↗
PubMed1991

Biochemical characteristics and plasmids of clinical and environmental Plesiomonas shigelloides.

The biochemical characteristics of 68 clinical and 5 environmental Plesiomonas shigelloides isolates were determined. The reactions for ONPG, phenylalanine deaminase, motility, lactose fermentation and salicin fermentation were different from previously published findings. The reactions of the clinical and environmental isolates were very similar. The isolates were also tested for the presence of plasmids, and 40% of the strains were found to harbor between one and seven plasmids. The findings of this study will be useful for the identification and characterization of this recently recognized enteric pathogen.

Animals↗
PubMed1991

Global distribution of a variant of the circumsporozoite gene of Plasmodium vivax.

The global distribution of a newly described variant of the Plasmodium vivax circumsporozoite (CS) gene was determined by genetic analysis of wild isolates. Whole blood specimens were collected on filter paper from patients infected with P. vivax in South America. West Africa, and the Indian subcontinent. P. vivax DNA was released from the filter paper samples, and the CS gene was amplified by polymerase chain reaction and analyzed for genetic variation. Amplified DNA was probed with oligonucleotide probes that hybridize with the predominant CS repeat region (PV210) and the variant CS repeat region (PV247) of P. vivax. The PV247 variant was found in all three geographically diverse areas. In addition, five of six consecutive patients studied had simultaneous infection with both the predominant and variant forms of P. vivax. These findings suggest that a single-epitope vaccine based on the predominant CS domain is unlikely to be protective on even a regional basis.

Africa, Western↗
PubMed1991

Etiology of childhood diarrhea in Beijing, China.

To determine the role of recently recognized enteropathogens in childhood diarrhea in China, 221 children with diarrhea and 108 controls seen at the Beijing Children's Hospital were studied during April and May 1989. Stools were examined for ova, parasites, and rotavirus, cultured for bacterial pathogens, and probed for enterotoxigenic Escherichia coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), and enteropathogenic adherence factor-positive (EAF+) E. coli. Pathogens were identified in 56.5% of children with diarrhea and 43.5% of controls (P = 0.04). Detection of enteropathogens was significantly greater in patients examined within 1 week of symptom onset (65%) than in patients examined later (39%; P = 0.01). ETEC was the most frequently detected pathogen in children with diarrhea, accounting for 20% of the cases. Other agents identified in patients included the following: salmonellae, 12%; rotavirus, 7%; EIEC, 7%; EHEC, 7%; members of the Aeromonas hydrophila group, 6%; EAF+ E. coli, 5%; Ascaris lumbricoides, 3%; shigellae, 3%; campylobacters, 2%; and Vibrio spp., 0.5%. The isolation rates of salmonellae (P = 0.02), EAF+ E. coli (P = 0.04), and mixed pathogens (P = 0.05) were significantly greater for diarrhea patients than for controls. Resistance to multiple antimicrobial agents occurred in 39% of the Salmonella isolates, 22% of the Aeromonas isolates, and 17% of the Shigella isolates. Multiresistant salmonellae (P = 0.05) and shigellae were recovered from diarrheal stools only. Ciprofloxacin, cefotaxime, and imipenem were the only agents tested to which all bacterial isolates were susceptible in vitro. These results suggest that both traditional and newly recognized agents are important causes of childhood diarrhea in Beijing and that therapy may be complicated by indigenous antimicrobial resistance.

Child, Preschool↗
PubMed1991

Determination of genetic variation within Plasmodium falciparum by using enzymatically amplified DNA from filter paper disks impregnated with whole blood.

A new method which allows the enzymatic amplification of DNA extracted from whole blood dried on filter paper disks is presented. The method was used to study heterogeneity within an erythrocyte-binding antigen (EBA-175) of Plasmodium falciparum. Blood specimens from malaria-infected patients in Southeast Asia and Africa were spotted onto filter paper, dried, and transported for processing. P. falciparum DNA was extracted by boiling the filter paper disks in the presence of Chelex-100 ion-chelating resin, amplified by the polymerase chain reaction, and analyzed for the presence of genetic variation. In all cases examined, plasmodial DNA was successfully amplified and characterized from filter paper disks. Hybridization of the polymerase chain reaction products with internal probes demonstrated simultaneous infection with two strains of P. falciparum in two patients. This technique represents a sensitive and practical field method for the determination of genetic variation within P. falciparum and the study of molecular epidemiology.

Animals↗
PubMed1991

Universal promoter for gene expression without cloning: expression-PCR.

We present a rapid and simple system called expression-PCR (E-PCR) for in vitro synthesis of functional protein from genomic or plasmid DNA. A universal promoter was developed containing an untranslated leader sequence from alfalfa mosaic virus directly downstream from the T7 bacteriophage promoter. When this universal promoter is spliced to a DNA segment, it produces a suitable template for in vitro transcription and translation. The DNA to be expressed is first amplified by the PCR using a 5'-primer that incorporates an area homologous to the 3'-end of the universal promoter. The universal promoter and this DNA fragment are mixed and re-amplified in a reaction analogous to splicing by overlap extension, generating a recombinant DNA template that can be transcribed and translated in vitro without further processing. Unlike standard methods for in vitro transcription and translation, E-PCR is not dependent upon specialized transcription vectors, cloning, plasmid isolation and purification, or restriction enzyme sites. This approach has been used to synthesize and examine the biological activity of malaria proteins that are vaccine candidates for Plasmodium falciparum. E-PCR represents a significant improvement over current in vitro expression systems, most notably in its time savings, versatility of gene expression and its compatibility with rapid PCR-based site-directed mutagenesis procedures.

Animals↗
PubMed1989

Antimicrobial susceptibility of Plesiomonas shigelloides from patients with diarrhea.

Antimicrobial susceptibility testing was performed on 72 fecal isolates of Plesiomonas shigelloides from patients with diarrhea by using a standard agar dilution technique. All isolates were obtained from a single geographic location. Based on the in vitro activities demonstrated in this study, norfloxacin, ciprofloxacin, and trimethoprim may be effective as oral agents in the treatment of P. shigelloides diarrheal disease. For the parenteral treatment of extraintestinal infection, netilmicin and the cephalosporins had the best in vitro activity.

Anti-Bacterial Agents↗
PubMed1989

Clinical features, epidemiology, and treatment of Plesiomonas shigelloides diarrhea.

Recent studies have suggested that Plesiomonas shigelloides is a cause of diarrhea. The present study addresses the clinical features, epidemiology, and response to antimicrobial therapy of P. shigelloides diarrhea. Thirty cases of P. shigelloides infection were defined by isolation of the organism from stool specimens, and 30 age-matched control patients were identified by detection of other enteric pathogens. Clinical and epidemiological information was obtained by interviewing the referring physicians and the patients. Of the P. shigelloides-infected patients, 71% had a history of recent tropical travel, but 29% acquired their infections locally in association with the consumption of seafood or untreated water or both. Seventy-eight percent of the P. shigelloides-infected patients had findings suggestive of colitis, and P. shigelloides-infected patients had a history of tropical travel, acute illness, abdominal pain, and prolonged symptoms significantly more often than did the control patients. Antimicrobial therapy significantly reduced the duration of illness in patients with Plesiomonas diarrhea. These results suggest that P. shigelloides is a significant cause of both locally acquired and traveler's diarrhea that may respond to antimicrobial therapy.

Adolescent↗
PubMed1988

Recurrent hydatid disease during pregnancy.

A Syrian woman with pulmonary and hepatic Echinococcus granulosus had symptoms of hydatid disease during each of three consecutive pregnancies. We postulate that the decrease in cellular immunity that accompanies pregnancy might allow for increased parasite growth. Obstetricians should be aware of the potential during pregnancy for rapid progression and complications of hydatid disease.

Abortion, Spontaneous↗
PubMed1987

Epidemiology and clinical features associated with Blastocystis hominis infection.

A retrospective chart review was performed on 100 patients infected with Blastocystis hominis (Bh) and 50 randomly selected age and sex matched controls to examine the clinical and epidemiologic features associated with this organism. The finding of greater than 5 Bh per oil immersion field (1,000 X) was significantly associated with acute presentation of symptoms but was not predictive of the presence of gastrointestinal symptoms. Of patients infected with Bh, 57.5% had recently travelled to the tropics or had consumed untreated water as compared to 12.2% of controls (p less than 0.001). Forty Bh-positive patients were assessed on more than one occasion. No significant differences appeared to exist in the clinical responses of those treated with Metronidazole (14/18; 77.8%) or with dietary management (6/6; 100%) as compared with those not receiving treatment (13/16:81.2%). Patients tended to become less symptomatic with time and in the absence of specific treatment, and therefore treatment with Metronidazole may not be warranted in light of the natural history of Bh infection.

British Columbia↗
PubMedDate not supplied

Demonstration by the polymerase chain reaction of mixed Plasmodium falciparum and P. vivax infections undetected by conventional microscopy.

Mixed malaria infections (Plasmodium falciparum and P. vivax) are suspected to occur at a greater frequency than is detected by conventional light microscopy. To determine this frequency we carried out a prospective 'blinded' comparison of diagnosis by conventional light microscopy and enzymatic amplification of the circumsporozoite gene extracted from dried spotted blood samples. Patients were previously healthy, active duty Thai soldiers assigned to a malaria risk area presenting with malaria. Microscopy (oil immersion objective at 1000 x magnification) involved examination of Giemsa-stained thick and thin blood films by an experienced microscopist. Whole blood samples (25 microliters) dried on filter paper were used for species-specific parasite deoxyribonucleic acid (DNA) amplification by the polymerase chain reaction (PCR) and hybridization with radiolabelled P. falciparum and P. vivax probes. Of 137 consecutive cases of malaria studied, 9% (3/32) of microscopically diagnosed P. falciparum infections and 5% (5/104) of microscopically diagnosed P. vivax infections were found to be mixed by the PCR/DNA probe systems, while 1 case was diagnosed as mixed by both microscopy and PCR. The possibility that malaria patients may have undetected mixed infections should be kept in mind because of the specific therapy required both for P. falciparum and for radical cure of P. vivax.

Amino Acid Sequence↗
PubMedDate not supplied

Arcanobacterium hemolyticum infection: confused with scarlet fever and diphtheria.

Arcanobacterium hemolyticum infections are a common cause of pharyngitis and rash in the 10- to 30-year-old age group. Despite its prevalence, many emergency and primary care physicians may not be aware of the pathogenic potential of this organism. We present a case that illustrates the distinctive clinical spectrum of A. hemolyticum infections that may be confused with drug allergy, group A streptococcal scarlet fever, diphtheria, and even toxic shock syndrome. Recognition of this syndrome will reduce misdiagnoses and facilitate appropriate treatment.

Adult↗
PubMedDate not supplied

Causal prophylactic efficacy of atovaquone-proguanil (Malarone) in a human challenge model.

Plasmodia infect the liver for about 7 days before subsequently infecting the blood. Present prophylaxis against Plasmodium falciparum malaria employs agents that primarily kill blood stages and must be continued for 28 days after the last exposure. Atovaquone-proguanil (Malarone) is a new antimalarial agent that is licensed in 35 countries as treatment against blood-stage infection, but its components (atovaquone and proguanil) have separately been shown to be active also against liver stages. To determine whether atovaquone-proguanil is sufficiently active against liver stages to be discontinued 7 days after exposure, we challenged 16 volunteers with P. falciparum via infected mosquitoes. Twelve volunteers received atovaquone-proguanil (1 tablet daily) on the day prior to challenge, on the day of challenge, and for the next 6 days; 4 volunteers received matching placebo. All placebo volunteers demonstrated parasitaemia and malarial symptoms beginning on days 11-12 after challenge. No atovaquone-proguanil volunteer acquired malaria. Atovaquone-proguanil is the first licensed antimalarial agent that kills P. falciparum in the liver and that may be discontinued 7 days after the last exposure.

Adolescent↗
PubMedDate not supplied

Efficacy of a 14-day primaquine regimen in preventing relapses in patients with Plasmodium vivax malaria in Mumbai, India.

We studied the antirelapse efficacy of a supervised 14-d 15 mg/d regimen of primaquine therapy (n = 131) compared with no antirelapse therapy (n = 142) in 273 patients with confirmed Plasmodium vivax malaria in Mumbai, India, between July 1998 and April 2000. There were 6/131 (4.6%) recurrences in patients given primaquine compared with 13/142 (9.2%) in those not given antirelapse therapy. In the 14-d primaquine group, polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) genotyping analysis of pre- and post-treatment blood samples was done for the 6 patients who had a recurrence of parasitaemia and the results gave a true relapse rate of 2.29% (3/131), 2 samples were classified as reinfections and 1 sample did not amplify. Our results indicate probable resistance to the 14-d regimen of primaquine for the first time in India and illustrate the need to (i) monitor patients given this regimen and (ii) carry out comparative studies between primaquine and new drugs such as tafenoquine and bulaquine for preventing relapses.

Adolescent↗