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Biomedical subjects

E D Franke

Publications and source records attributed to E D Franke.

30 records · Page 2Linked to original sources
PubMed1990

Diffuse cutaneous leishmaniasis acquired in Peru.

A case of diffuse cutaneous leishmaniasis (DCL) acquired in Peru is described. The causative agent was Leishmania mexicana amazonensis as determined by isoenzyme analysis and species-specific monoclonal antibody binding characteristics. Histological examination of biopsy material showed a large number of intracellular and extracellular amastigotes and few lymphocytes. Treatment with meglumine antimoniate (Glucantime) administered iv at a dosage of 20 mg antimony/kg body weight/day for 60 days resulted in visible improvement of the lesions, but not in clinical or parasitological cure.

Adult↗
PubMed1990

Evaluation of medium supplements for in vitro cultivation of Wuchereria bancrofti.

Third-stage larvae (L3) of Wuchereria bancrofti molt to the fourth stage in an in vitro culture medium composed of NCTC 135 and Iscove's modified Dulbecco's medium (1:1; v/v) supplemented with 10% human serum and a mixture of anti-bacterial and anti-mycotic agents. In the present investigation this culture medium was used to examine the effects of different concentrations of human serum, medium supplements, and serum replacements on larval growth, development, and molting. Several medium supplements and serum replacements were evaluated including hemin, Nutridoma, and a mixture of soybean lipids, bovine serum albumin, and transferrin. The supplements tested could not support larval growth and development in the absence of serum and they did not have an enhancing effect on larval growth and development in combination with human serum. A medium supplement of 30% human serum resulted in molting of 80-94% of L3s and optimum growth to the mid to late fourth stage. This culture system provides an excellent alternative to experimentally infected animals as a source of larvae undergoing the third molt and fourth-stage larvae for screening potential anti-filarial compounds and for immunologic and biochemical studies.

Animals↗
PubMed1988

Immune response of humans to the circumsporozoite protein of Plasmodium falciparum: limited T cell response to the immunodominant central repeat region.

Most adults in highly malarious areas have antibodies to the repeat region of the circumsporozoite protein of Plasmodium falciparum. To determine if a T cell epitope on the repeat region stimulated T cell help for this antibody, we used R32tet32, a recombinant construct derived from the repeat region of the circumsporozoite protein of P. falciparum, to stimulate in vitro mononuclear cells from residents of an area hyperendemic for malaria. Three groups differing in the length of time they had resided in a malarious area were studied. The percentage of individuals in each group who had positive antibody responses to R32tet32 increased with increased exposure to malaria. However, antibody positivity was not correlated with in vitro lymphocyte proliferation responses to the antigen. Lymphocytes from 79% of the individuals showing serum antibodies to R32tet32 failed to respond in a lymphocyte transformation assay, suggesting that T cell helper activity in these individuals was based upon the recognition of a T cell epitope not located within this peptide.

Animals↗
PubMed1987

Leishmania braziliensis: protein, carbohydrate, and antigen differences between log phase and stationary phase promastigotes in vitro.

When Leishmania species are grown in vitro, parasites from the stationary phase differ from those in log phase growth in being more infective and more resistant to complement and macrophage mediated killing. In the present study, log phase and stationary phase promastigotes of Leishmania braziliensis panamensis were compared at the molecular level. Differences in polypeptide and glycoprotein composition and antigenicity between log and stationary phase promastigotes of L. b. panamensis were detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting; the former showed that two polypeptides were unique to log phase promastigotes and one was unique to stationary phase promastigotes. There were also differences in surface lectin binding characteristics of log and stationary phase promastigotes. Live stationary phase promastigotes bound more concanavalin and lentil lectin than log phase promastigotes, indicating a greater number of mannose residues on their surfaces.

Animals↗
PubMed1987

Monoclonal antibody to a unique surface epitope of the human filaria Brugia malayi identifies infective larvae in mosquito vectors.

We describe properties of an IgM monoclonal antibody (NEB-D1E5) raised against the human filarial parasite Brugia malayi. The antibody reacts with a stage- and species-specific determinant located on the surface of the infective-stage larva, as determined by indirect immunofluorescence. To use this reagent in epidemiological field studies, we developed an enzyme-linked immunoassay with which B. malayi larvae can be differentiated from other filarial parasites in mosquito vectors, including the morphologically indistinguishable parasite of animals Brugia pahangi. The immunoenzyme assay was 91-94% specific and 90-97% sensitive when performed on infected mosquitoes. In the absence of mosquito tissue, the levels of specificity and sensitivity increased to 100% and 97.5-100%, respectively. Binding of antibody to the surface of living larvae was abrogated by treatment of the worms with the enzymes pronase and proteinase K and with the detergents Triton X-100, octyl beta-D-glucopyranoside, and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulphonate (CHAPS). In contrast, treatment with trypsin, endoglycosidase-F, O-Glycanase, N-Glycanase, lipase, various phospholipases, boiling, 2-mercaptoethanol at 37 degrees C, or periodate did not reduce the antigenicity of the larval surface to antibody NEB-D1E5. These results suggest that the species-specific epitope is a peptide domain attached to a hydrophobic anchoring residue.

Animals↗
PubMed1987

In vitro cultivation of third stage larvae of Wuchereria bancrofti to the fourth stage.

Third stage larvae of Wuchereria bancrofti obtained from laboratory-infected mosquitoes grew and molted to the fourth stage in vitro. The culture medium which supported the best growth and development consisted of a 1:1 mixture (v/v) of two commercially available cell culture media, NCTC 135 and Iscove's modified Dulbecco's medium supplemented with 10% human serum or plasma and an antibacterial/antimycotic mixture. Cultures were incubated at 37 degrees C in an atmosphere of either 5% or 8% CO2 in air. After 35 days of culture, 65% to 100% of the larvae were fourth stage. They were motile and in excellent morphological condition with development of the reproductive system in males and females. This culture system will provide an important tool for biochemical and immunological studies.

Aedes↗
PubMed1987

Detection and enumeration of Leishmania in sand flies using agar-based media.

An agar plating technique was used to determine the number of amastigotes ingested by Lutzomyia longipalpis fed on papules on Mesocricetus auratus caused by Leishmania mexicana amazonensis and on lesions on Mystromys albicaudatus caused by Leishmania braziliensis panamensis. The technique involved homogenizing sand flies after bloodfeeding on the infected animals and spreading the homogenate over the surface of agar plates. A great variation in the number of amastigotes ingested by individual sand flies was demonstrated. Not all amastigotes ingested developed anterior stomodeal infections.

Animals↗
PubMed1985

Growth cycle-dependent generation of complement-resistant Leishmania promastigotes.

The ability of in vitro grown Leishmania promastigotes to resist lysis by complement and survive in undiluted human serum was related to the species of Leishmania and the growth phase in culture. Promastigotes from log phase cultures were always killed in undiluted serum, whereas survival of stationary phase promastigotes varied among species. All L. major and L. m. amazonensis were killed, while up to 30% of L.b. panamensis and 10% of L. donovani survived. Lysis of promastigotes by human serum was inhibited in heat-inactivated serum and EDTA-chelated serum, indicating that activation of complement was responsible for killing. Therefore, during growth in vitro, some strains of Leishmania promastigotes can undergo development from a complement-susceptible to -resistant stage. Stationary phase promastigotes of L.b. panamensis which survived in undiluted human serum were capable of subsequent growth in culture, and were also able to initiate infection in Mystromys albicaudatus. Organisms selected on the basis of complement resistance were more infective for M. albicaudatus than either log phase promastigotes or unselected promastigotes from stationary cultures. These data support the notion that the life cycle of Leishmania includes an infective stage promastigote which is generated during growth within the sandfly and which, on inoculation, is able to survive the potentially lethal effect of normal serum before uptake by host macrophages.

Adult↗
PubMed1984

In vitro cultivation of Dipetalonema viteae third-stage larvae: effect of the gas phase.

The effect of the gas phase on the in vitro growth and development of Dipetalonema viteae (Nematoda: Filarioidea) third-stage larvae obtained from the tick vector and 3 day infections of jirds was examined. Measurements of the oxygen (pO2) and carbon dioxide (pCO2) tensions and the pH in the medium were made for each gas phase. In cultures gassed with 5% carbon dioxide in nitrogen the pO2 was between 32 and 50 mm Hg, the pCO2 ranged from 25 to 40 mm Hg and the pH was between 7.2 and 7.4. This gas phase resulted in the best growth and development of third-stage larvae to the fourth-stage. Survival and development of larvae were decreased in cultures with oxygen tensions less than 20 mm Hg and greater than 50 mm Hg.

Animals↗
PubMed1984

In vitro cultivation of Dipetalonema viteae third-stage larvae: evaluation of culture media, serum, and other supplements.

Third-stage larvae of Dipetalonema viteae obtained from the tick vector developed to the fourth stage in several cell-free culture systems. Survival and development of larvae in a number of commercially available cell culture media, supplemented with serum and other defined and undefined components, were compared. All cultures were gassed with 5% carbon dioxide in nitrogen. Best survival, growth and development were obtained in stationary cultures containing 1:1 (v/v) mixtures of NCTC 135, either RPMI 1640 or Iscove's Modified Dulbecco's Medium, and a supplement of 20% non-heat-inactivated fetal bovine serum. The importance of the medium composition and physical environment of the culture system, for the survival, growth and development of D. viteae was demonstrated.

Animals↗
PubMed1983

Dipetalonema viteae (Nematoda: Filarioidea): culture of third-stage larvae to young adults in vitro.

Infective third-stage larvae of Dipetalonema viteae (Nematoda: Filarioidea) were cultured to young adults in a cell-free culture system. Third-stage larvae from the tick vector grew, developed, and molted twice in a medium containing NCTC 135 and Iscove's modified Dulbecco's medium supplemented with fetal bovine serum under a gas phase of 95 percent nitrogen and 5 percent carbon dioxide. The availability of such a culture system for filariids should facilitate studies of their immunology, biochemistry, and sensitivity to drugs.

Animals↗