Superiority of the neonatally thymectomized Lewis rat (NTLR) to monitor a clinical trial in lepromatous leprosy of the two regimens of rifampin and dapsone.

The ability of the neonatally thymectomized Lewis rat (NTLR) and the congenitally athymic (nude) rat systems to detect low numbers of viable Mycobacterium leprae in tissues from lepromatous leprosy patients undergoing short-course chemotherapy was compared with that of the commonly employed mouse foot pad assay. Fifteen previously untreated lepromatous patients were randomly assigned to treatment regimens of either a single initial 1500 mg dose of rifampin plus daily doses of 100 mg of dapsone, or weekly doses of 900 mg of rifampin plus daily doses of 100 mg of dapsone. Four skin biopsies from each patient taken sequentially up to one month after initiation of therapy were used as the source of the M.

Cultivation of pathogenic treponema in tissue cultures of SflEp cells.

Recently, the successful in vitro cultivation of the Nichols strain of Treponema pallidum was achieved. Afterward, attempts were made to cultivate three other strains of T. pallidum and two strains of T.

T-cell lineage of a Friend virus-induced lymphatic leukemia in athymic rats.

Athymic (rnu/rnu) and euthymic rats inoculated with the Friend virus-associated lymphatic leukemia virus developed lymphocytic leukemia. Neoplastic cells from these animals were evaluated by means of indirect immunofluorescence and flow cytofluorometry with monoclonal antibodies Ox-1, Ox-7, and W3/25, which react with surface antigens present on normal rat lymphoid cell populations. Lymphoid cells from leukemic animals revealed characteristic alterations in cell surface fluorescence profiles when compared to normal, healthy controls.

Infection of the congenitally athymic rat with Mycobacterium leprae.

The susceptibility of congenitally athymic rats to Mycobacterium leprae infection has been investigated. Following inoculation of small numbers of M. leprae (5 X 10(3] into the foot pad, the organisms replicated and attained a maximum of 2.

Freeze-drying is an effective method for preserving infectious type C retroviruses.

Conventional freeze-drying techniques using a sucrose stabilizer and gelatin can be employed to preserve the infectivity of retroviruses. Lyophilized virus retains its infectivity even at room temperature for more than one year. A lyophilized virus preparation of Friend leukemia virus kept at 4 degrees C for more than 20 years was found to contain high titers of infectious pathogenic virus.

Biological characteristics and viral susceptibility of a stable dog kidney cell line.

A cell line derived in 1956 from normal dog kidney is described. The cells are epithelial, contact-inhibited, and can be maintained in the same culture vessels for period of more than 2.5 yr.

1,25-dihydroxyvitamin D3 receptors in human epithelial cancer cell lines.

Specific, high-affinity cytosolic receptors for 1,25-dihydroxyvitamin D3 have been demonstrated in five human cancer cell lines. The cell lines were derived from tumors of breast, lung, cervix, and melanotic and amelanotic melanomas. Binding affinity (Kd) of the receptors for 1,25-dihydroxyvitamin D3 were all approximately 0.

Further studies on replication of virulent Treponema pallidum in tissue cultures of Sf1Ep cells.

A number of parameters aimed at optimizing culture conditions for both Sf1Ep cells and Treponema pallidum have been investigated. Optimum temperature for replication of T. pallidum ranged between 33 and 35 degrees C.

Relationship between T-cell population in neonatally thymectomized Lewis rats and susceptibility to infection with mycobacterium leprae.

The neonatally thymectomized Lewis rat (NTLR) is highly susceptible to infection with M. leprae. However, a significant percentage of NTLR respond to infection with M.

Cultivation of virulent Treponema pallidum in tissue culture.

In a series of seven experiments, the virulent Nichols strain of Treponema pallidum was shown to attach and replicate on the surface of tissue culture cells of cottontail rabbit epithelium (Sf1Ep) growing in conventional monolayer cultures under an atmosphere of 1.5% oxygen. Five days after inoculation of 10(6)T.

Growth and regression of human tumor cell lines in congenitally athymic (rnu/rnu) rats.

Athymic rats were inoculated with cells from nine human tumor tissue culture cell lines. Tumor growth was seen with seven of the cell lines; histologically, the tumors resembled the tumors from which the cell lines were originated. Only one cell line--a malignant melanoma--grew progressively.

Role of serum in survival of Treponema pallidum in tissue culture.

During attempts to cultivate Treponema pallidum, it was determined that length of time for survival of virulent treponemes was highly dependent on the quality of the fetal bovine serum (FBS) used as a protein supplement in the culture medium. Eighteen lots of commercial FBS were tested for their ability to maintain survival of T. pallidum in cultures of cottontail rabbit epithelial (SflEp) cells.

Combined rifampin and dapsone chemotherapy of Mycobacterium leprae infection of the neonatally thymectomized Lewis rat.

Neonatally thymectomized Lewis rats (NTLR) were shown to be highly susceptible to infection with Mycobacterium leprae. We have used them in chemotherapeutic studies as models of human lepromatous leprosy. NTLR chronically infected with M.

Genetic relationship between Treponema pallidum and Treponema pertenue, two noncultivable human pathogens.

Genetic relationships among two strains of Treponema pallidum (Nichols and KKJ) and a strain of T. pertenue were determined by measuring the degree of deoxyribonucleic acid sequence homology. The results in indicated that these three virulent, noncultivable treponemes were genetically indistinguishable.

Neonatally thymectomized Lewis rats infected with Mycobacterium leprae. 2. Histopathologic and electron microscopic observations.

We report the histologic and electron microscopic findings following intravenous inoculation of M. leprae into neonatally thymectomized Lewis rats, which were killed one to two years later. All organs appeared normal grossly.

Comparative behavior of virulent strains of Treponema pallidum and Treponema pertenue in gradient cultures of various mammalian cells.

Two strains of virulent Treponema pallidum and two of virulent T. pertenue were investigated for their ability to attach to and survive in gradient cultures of five different mammalian cells under aerobic conditions. The strains of T.

Erythroid leukemia induced by Friend lymphatic leukemia virus in T-cell-depleted mice.

BALB/c mice depleted of T-cells by thymectomy at 3 to 5 days of age and by treatment with antithymocyte serum were inoculated with the lymphatic leukemia virus derived from Friend virus. After a long latent period, these animals developed erythroid leukemia. In contrast, intact control mice inoculated with Friend virus-associated lymphatic leukemia virus developed typical thymic (T-cell) lymphomas.

Genetics of Treponema: characterization of Treponema hyodysenteriae and its relationship to Treponema pallidum.

Saturation reassociation assays with 125I-labeled treponemal DNAs show that Treponema hyodysenteriae is genetically unrelated to T. pallidum (Nichols), T. phagedenis biotype Reiter, and T.

Genetics of Treponema: relationship between Treponema pallidum and five cultivable treponemes.

Three genetically distinct groups of treponemes have been identified by saturation reassociation assays using 125I-labeled treponemal DNAs. The three groups are (i) virulent Treponema pallidum (Nichols strain), (ii) T. phagedenis and its biotypes Reiter and Kazan 5, and (iii) T.

Prolonged survival of virulent Treponema pallidum (Nichols strain) in cell-free and tissue culture systems.

Survival of Treponema pallidum was found to be prolonged in the presence of tissue culture. Of the 12 cultures studied, cottontail rabbit epithelium (Sf1Ep) supported T. pallidum for the longest time.

New method for concentration and quantitation of Mycobacterium leprae.

A new method of enumerating Mycobacterium leprae has been developed. Suspensions containing the organisms were filtered through a polycarbonate membrane filter (25-mm diameter, 0.4-micronm pore size, 10-micronm thick; Nucleopore) to concentrate the organisms.