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Biomedical subjects

L Hendrix

Publications and source records attributed to L Hendrix.

At least 19 recordsLinked to original sources
PubMed2005

Production of recombinant protein Pap31 and its application for the diagnosis of Bartonella bacilliformis infection.

Tropical bartonellosis is a highly fatal epidemic and endemic infectious disease that occurs throughout the communities of the Andes Mountains in South America. The disease is caused by the facultative intracellular bacteria, Bartonella bacilliformis. The emergence of bartonellosis in new geographic areas and an increase in the number of reported cases suggest the need for a rapid test for epidemiologic study and investigation of the disease burden. The objective of this research is to develop a rapid serologic diagnostic test using recombinant antigens to overcome the limitations of the current standard IFA technique for laboratory diagnosis. Western blot analysis with patient sera of whole cell lysate separated on a 2D gel identified Pap31 as a dominant antigen. PCR primers were designed according to the sequence of ATCC strain 35685 to amplify the gene coding for Pap31 from a local isolate (HOSP 800-09, Peru). The amplicon was subsequently cloned into pET24a, adding the T7 tag, and expressed in E. coli. Patient sera with different IFA titers confirmed the diagnostic band of 31 kDa on a Western blot of SDS-PAGE. The performance of affinity-purified recombinant Pap31 (rPap31) was also evaluated in an ELISA format with 137 patient sera of known IFA titers. The range of ELISA reading from positive sera did not overlap with the range of those from negative sera, suggesting the potential application of rPap31 in both ELISA for high throughput regional hospital settings and in the construction of handheld rapid tests for rural clinical sites.

Antigens, Bacterial↗
PubMed2000

Using an interview guide to identify effective nurse managers: phase II, outcomes.

The investigators report validation of a survey tool called the Interview Guide to assist in the selection of nurses who will be effective as managers. Nurse administrators rated nurse managers at six months and two years after hire. The Interview Guide rated the management qualities "seeing the big picture" and potential for "rehire" as the best predictors of managerial success. After two years, a good "self-concept" or a "flexible attitude" was the best predictor. The ability to manage conflict was the most significant competency for predicting rehire at both six months and two years.

Adult↗
PubMed1997

Plasmodium falciparum chloroquine and quinine sensitivity in asymptomatic and symptomatic children in São Tomé Island.

Plasmodium falciparum sensitivity to quinine in São Tomé was determined by in vivo and in vitro tests in 56 children with mild or cerebral malaria. Chloroquine sensitivity was assessed by in vitro tests in 105 parasitaemic asymptomatic children from the same community as the cases. The WHO standard methodology was used. No resistance to quinine was found by in vivo or in vitro tests in either group of patients or in asymptomatic children, although some degree of chloroquine resistance was found with the in vitro test. This was more common in patients than in asymptomatic children. Chloroquine resistance may be explained by the recent history of malaria in São Tomé Island, which caused an important decrease of immunity among the population and consequently the emergence of resistant strains. Implications of the use of in vivo/in vitro tests for determining the antimalarial drug policy within the primary health care system are discussed.

Adolescent↗
PubMed1994

A highly efficient in vitro cloning procedure for asexual erythrocytic forms of the human malaria parasite Plasmodium falciparum.

A very reliable and productive technique for cloning of Plasmodium falciparum in vitro is proposed, as demonstrated by successive limiting dilution of suspensions of asexual erythrocytic forms of the NF 54 strain. The introduction and the study of reliable clones is of extreme importance for a better understanding of the behaviour of the parasite, also in field conditions. The method is rapid, simple and efficient. The growth of the clones was individually monitored and the culture conditions were constantly adjusted during their stay in recipients of increasing size. A yield of 18/96 (18.75%) of provisional clones was obtained, while the supercloning phase resulted in 16/80 (20%) positive cultures. The probability that the latter were derived from a single progenitor is very high (99%). It was shown that three randomly selected clones (A1A9, A1B11, and A1C10) have excellent growth characteristics before and after cryopreservation, and after a longer period of culture in standard conditions.

Animals↗
PubMed1990

Composite Hodgkin's and non-Hodgkin's lymphoma in a patient with acquired immune deficiency syndrome. In-situ demonstration of Epstein-Barr virus.

A 44-year-old man infected with human immunodeficiency virus had Hodgkin's disease, mixed cellularity, and malignant non-Hodgkin's lymphoma, diffuse large cell type. Colorimetric in-situ hybridization showed the Epstein-Barr virus (EBV) genome in the cells of the large cell non-Hodgkin's lymphoma and in the Reed-Sternberg cells and reactive lymphocytes of the Hodgkin's lymphoma. These results suggest that EBV may play a similar causative role in both neoplasms. This colorimetric method of hybridization, yielding results within 8 hours, is applicable to archival material and will be useful in further epidemiologic work associating EBV and lymphoid proliferations and malignancies.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Magnetic resonance imaging of juxtapapillary plaques in cadaver eyes.

Adequate treatment of juxtapapillary melanomas with episcleral plaque brachytherapy using lower energy radiation sources may be difficult because of uncertainties regarding the relationship of the plaque to the optic nerve and tumour base. We obtained magnetic resonance images of a dummy plaque placed in a juxtapapillary location in cadaver specimens. Although it is possible to place a plaque in close association with the optic nerve sheath, a tissue barrier exists which may prevent actual contact between the plaque and nerve. Posterior tilting of the plaque may also occur. Because of these uncertainties regarding plaque placement, juxtapapillary melanomas should be considered a distinct subgroup when evaluating the efficacy of radioactive plaque brachytherapy in the treatment of choroidal melanoma.

Brachytherapy↗
PubMed1990

[Malaria index according to age and seasons in the health region of Katana, in mountainous Kivu, Zaire].

A longitudinal malaria survey was undertaken in children under five in 5 villages of Katana Rural Health Zone in Kivu, East Zaire. During the year 1983, seasonal fluctuations ranging from 25 to 44% were observed in the parasitological index as well as concomitant variations from 5 to 18% in the splenic index. More malaria transmission seems to occur during the long dry season (June to September). In order to prepare an operational research project to be conducted in two geographically delimited areas of the Health Zone, a complementary survey was organised in February 1985. This survey yielded details on parasitological, splenic and serological index in relation to age. These malaria indices were similar in the two areas and all gradually increased with age to reach maxima of respectively 42%, 13% and 55%. The Katana region, situated at an altitude of 1500 meters, on the shores of lake Kivu, is apparently characterized by an unstable and meso-endemic malaria. The applicability and feasibility of some alternative malaria control strategies are discussed.

Adult↗
PubMed1984

Active transport of proline by Coxiella burnetii.

The obligate intracellular rickettsia, Coxiella burnetii, was shown to possess an energy dependent proline transport system which displayed a high degree of specificity and was highly dependent on pH. Transport was maximal at pH 3.0 to 4.5, a pH range approximately that of the host cell phagolysosome where the agent replicates. Transport was inhibited by the uncouplers carbonyl cyanide m-chlorophenylhydrazone and dinitrophenol, but not by sodium arsenite. In the presence of glutamate, a preferred energy source, proline uptake was enhanced more than two-fold. This enhancement of proline uptake was greatly decreased in the presence of sodium arsenite. The addition of glutamate decreased the apparent Km for proline transport from 45 microM to 15 microM, with the Vmax increasing from 3.6 pmol s-1 (mg dry wt)-1 to 4.8 pmol s-1 (mg dry wt)-1. Two proline analogues, furoic acid and azetidine-2-carboxylic acid, were effective inhibitors of proline transport. D-Proline, 4-hydroxyproline, glycine and proline amide inhibited transport minimally, while no inhibition was seen with succinate, pyruvate or glutamate.

2,4-Dinitrophenol↗
PubMed1978

Demonstration of a platelet bypass mechanism in the clotting system using an acquired anticoagulant.

A lupus-type anticoagulant which causes strong inhibition of the partial thromboplastin time with kaolin (PTTK), the stypven time, and the thrombin generation tests has been investigated. All tests for platelet function were normal, as were all specific coagulation factor assays with the exception of a slightly reduced factor XI in this patient. A diethylaminoethyl-cellulose-immunoglobulin (DEAE-cellulose-IgG) fractionation of the patient's plasma produced two peaks containing inhibitory activity in the PTTK test. The first of these peaks had a cloudy appearance, suggesting the presence of immunoglobulin aggregates. Studies with IgG aggregates prepared from normal IgG and from the patient's IgG demonstrated that such aggregates were not the cause of inhibition. It was possible to neutralize the inhibitory activity of the purified IgG but not platelet-poor plasma (PPP) with a rabbit anti-IgG. The inhibition of the patient's PPP in the thrombin generation, the contact product, and the stypven time tests were corrected by the inclusion in the test system of platelets activated either by aggregation due to adenosine diphosphate (ADP) or formalin fixation and washing. These studies lend support to earlier findings that platelets interact at several sites in the coagulation cascade.

Antibodies↗