10026
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HIGHMAN B, ALTLAND PD. Effect of exposure and acclimatization to cold on susceptibility of rats to bacterial endocarditis. Exp Biol Med (Maywood) 1998; 110:663-7. [PMID: 13907257 DOI: 10.3181/00379727-110-27610] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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10027
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RAPP F. Observations of measles virus infection of human cells. III. Correlation of properties of clones of H.Ep.-2 cells with their susceptibility to infection. Virology 1998; 10:86-96. [PMID: 14436277 DOI: 10.1016/0042-6822(60)90008-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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10028
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BARLOW AJ, CHATTAWAY FW, BRUNT RV, TOWNSLEY JD. A study of susceptibility to infection by Trichophyton rubrum. J Invest Dermatol 1998; 37:461-8. [PMID: 13865047 DOI: 10.1038/jid.1961.145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10029
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WOODS JW, WELT LG, HOLLANDER W. Susceptibility of rats to experimental pyelonephritis during potassium depletion. J Clin Invest 1998; 40:599-602. [PMID: 13786572 PMCID: PMC290758 DOI: 10.1172/jci104289] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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10030
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10031
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GUY LR, CHAPMAN JS. Susceptibility in vitro of unclassified mycobacteria to commonly used antimicrobials. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1998; 84:746-9. [PMID: 13903222 DOI: 10.1164/arrd.1961.84.5p1.746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10032
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Drake WM, Coyte D, Camacho-Hübner C, Jivanji NM, Kaltsas G, Wood DF, Trainer PJ, Grossman AB, Besser GM, Monson JP. Optimizing growth hormone replacement therapy by dose titration in hypopituitary adults. J Clin Endocrinol Metab 1998; 83:3913-9. [PMID: 9814468 DOI: 10.1210/jcem.83.11.5223] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although growth hormone (GH) replacement therapy is increasingly utilized in the management of adult hypopituitary patients, optimum dosing schedules are poorly defined. The use of weight-based or surface area-based dosing may result in overtreatment, and individual variation in susceptibility on the basis of gender and other factors is now being recognized. To optimize GH replacement and to explore further gender differences in susceptibility, we used a dose titration regimen, starting at the initiation of GH replacement therapy, in 50 consecutive adult-onset hypopituitary patients, and compared the results with those in 21 patients previously treated using a weight-based regimen. Titrated patients commenced GH 0.8 IU/day subcutaneously (0.4 IU/day if hypertensive or glucose tolerance impaired). Serum insulin-like growth factor I (IGF-I) was measured at 0, 2, 4, 6, 8, 10, and 12 weeks in all patients. Serum IGF binding protein 3 and acid labile subunit were measured at the same time points in 17 patients (8 male, 9 female). Patients were reviewed every 4 weeks and the dose of GH increased, if necessary, to achieve a serum IGF-I level between the median and the upper end of the age-related reference range. There was no significant difference between mean serum IGF-I at 2 and 4 weeks, or between 6 and 8 weeks, indicating that the full effects of a change in dose are evident within 2 weeks of that change. Maintenance doses were significantly higher in females than males [1.2 (0.8-2.0) vs. 0.8 (0.4-1.6) IU/day; median (range); P < 0.0001], and the median time to achieve maintenance dose was significantly shorter in males [4 (2-12) vs. 9 (2-26) weeks; P < 0.0001]. Median maintenance dose was lower overall than in a group of 21 patients initially commenced on GH using a weight-based dosing schedule, with subsequent adjustment of dose during clinical follow-up [1.5 (0.4-3.2) IU/day; P = 0.02]. Reduction in waist measurement and waist to hip ratio at 6 and 12 months was similar in females (P < 0.001) and males (P < 0.01). Well-being improved significantly after 3 months of GH therapy (14.2 +/- 5.9 vs. 7.4 +/- 4.5 SD; P < 0.0001), and there were no gender differences. Adult Growth Hormone Deficiency Assessment (AGHDA) scores at 6 months were similar to maintenance scores in patients commenced on weight-based regimens. Measurements of ALS and IGFBP-3 added no useful extra information to IGF-I in managing the dose titration. The practical scheme outlined for dose titration of GH replacement resulted in rapid achievement of lower maintenance doses than those achieved using conventional weight-based regimens without loss of efficacy. It was particularly important in female patients who demonstrated decreased overall sensitivity to GH and required higher doses to achieve the same effects as males. This constitutes the first report of a uniform titration regimen based on a defined target range of serum IGF-I in a large patient cohort.
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10033
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Brubaker JF, Turell MJ. Effect of environmental temperature on the susceptibility of Culex pipiens (Diptera: Culicidae) to Rift Valley fever virus. JOURNAL OF MEDICAL ENTOMOLOGY 1998; 35:918-921. [PMID: 9835680 DOI: 10.1093/jmedent/35.6.918] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Studies were conducted to determine the effect of environmental temperature on the susceptibility of Culex pipiens (L.) to Rift Valley fever (RVF) virus. Larval rearing temperature (13, 17, 19, or 26 degrees C) did not affect the susceptibility of adult female Cx. pipiens to infection with RVF virus. In contrast, the adult holding temperature after a viremic blood meal affected infection rates in females. Significantly fewer mosquitoes contained detectable virus when they were held at cooler temperatures, 13 degrees C (10%), 17 degrees C (20%), and 19 degrees C (41%) than at a warmer temperature, 26 degrees C (91%). For mosquitoes held at 13 degrees C and then switched to 26 degrees C, infection rates increased steadily with increased time at 26 degrees C. There was no effect on the ability to detect RVF virus in adult females that were subjected to cooler holding temperature (17 degrees C) after they were first held at warmer temperature (26 degrees C). The role of environmental temperature needs to be considered in studies on the epidemiology of arthropod-borne viruses.
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10034
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Abstract
Mice varying in age from 1 day to 8 months were inoculated intraperitoneally with Coxsackie A virus, type 9 and studies were made of the quantity of virus in striated muscle and myocardium, the presence of neutralizing antibody in the serum, and the pathological changes in the tissues. The hind limbs of young (1- to 20-day-old) mice yielded high titers of virus and showed diffuse myositis, whereas only low yields of virus and focal myositis were obtained in older mice. In the 20-day-old mice the skeletal lesions were not accompanied by manifest symptoms and histologically showed evidence of regeneration progressing from the 3rd to the 11th day after inoculation. Older mice showed no symptoms and only focal myositis and low yields of virus were found in their hind limbs. Coxsackie A9 virus replicated to relatively low titers in the hearts of young (1- to 40-day-old) mice without producing any demonstrable lesions whereas frank myocarditis with high yields of virus were demonstrated in mice infected at 8 months of age. The data suggest that at least for the 2 strains used, the adult mouse should be considered susceptible to subclinical infection with Coxsackie A9 virus. Neither subclinical infection, nor antibody formation was demonstrable in young adult mice inoculated with a strain of Coxsackie A4 virus.
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10035
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10036
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Fife KH. Human papillomavirus vaccine development. Australas J Dermatol 1998; 39 Suppl 1:S8-10. [PMID: 9842094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The greatest successes in combating important viral infections have been achieved using vaccines. A vaccine to prevent genital tract human papillomavirus (HPV) infections, especially those types associated with genital tract malignancy, could significantly reduce morbidity and mortality from cervical and other genital tract cancers. However, several barriers currently stand in the way of HPV vaccine development. The immunological response to natural HPV infection is incompletely understood and there is uncertainty about which viral antigen(s) should be included in a candidate vaccine. It is clear that immunization of several animal species with the L1 major capsid protein (usually in the form of virus-like particles) spurs the production of anti-HPV antibodies that are neutralizing in several assay systems. However, it is not clear if neutralizing antibody will be present in the genital tract in sufficient quantities to block infection. A second problem is the lack of a reliable serological assay for HPV. This is a major problem for clinical trials in which the identification of susceptible individuals, and incident infections, usually relies on serological diagnosis. Finally, there is also interest in the development of a vaccine that is used to treat individuals who are already infected--a therapeutic vaccine. It is likely that a therapeutic vaccine will need to target different or additional antigens to those comprising a prophylactic vaccine.
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MESH Headings
- Animals
- Antibodies, Viral/biosynthesis
- Antigens, Viral/therapeutic use
- Capsid/immunology
- Condylomata Acuminata/immunology
- Condylomata Acuminata/prevention & control
- Condylomata Acuminata/therapy
- Condylomata Acuminata/virology
- Disease Susceptibility
- Female
- Genital Diseases, Female/immunology
- Genital Diseases, Female/prevention & control
- Genital Diseases, Female/therapy
- Genital Diseases, Female/virology
- Genital Diseases, Male/immunology
- Genital Diseases, Male/prevention & control
- Genital Diseases, Male/therapy
- Genital Diseases, Male/virology
- Humans
- Male
- Papillomaviridae/immunology
- Papillomavirus Infections/immunology
- Papillomavirus Infections/prevention & control
- Papillomavirus Infections/therapy
- Papillomavirus Vaccines
- Tumor Virus Infections/immunology
- Tumor Virus Infections/prevention & control
- Tumor Virus Infections/therapy
- Viral Vaccines/chemical synthesis
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10037
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MILLER CP, HAMMOND CW, ANDERLE SK. Studies on susceptibility to infection following ionizing radiation. V. Comparison of intraperitoneal and intravenous challenge at intervals following different doses of x-radiation. ACTA ACUST UNITED AC 1998; 111:773-84. [PMID: 13770739 PMCID: PMC2137291 DOI: 10.1084/jem.111.6.773] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Ten week old female CF-1 mice were subjected to a single total body exposure of x-radiation in one of the following doses: 300, 400, and 500 r. At intervals thereafter, susceptibility to bacterial infection was determined by intraperitoneal challenge with graded inocula of Pseudomonas aeruginosa. Mice exposed to 400 or 500 r were also challenged by intravenous inoculation. The LD(50) of the test microorganism in each challenge was estimated from the mortality data. Exposure to 300 r caused little increase in susceptibility to this experimental infection. 400 r caused a moderate increase on the 3rd day post-irradiation with return to normal on the 17th. Leucocyte counts (geometric means) following this dose of radiation did not fall below 1200. 500 r caused a marked increase in susceptibility which lasted from the 3rd to 11th day, during which period the leucocyte counts were below 800. On the 20th day, susceptibility to infection was normal, although the geometric mean of leucocyte counts was only 2200. Comparison of mortalities resulting from equivalent inocula introduced by the two routes (intravenous and intraperitoneal) showed no difference in unirradiated mice. However, among mice irradiated with 400 or 500 r, higher mortalities resulted from intravenous inoculation. The difference was found to be due to the establishment of a small focus of infection at the site of intravenous injection as a result of leakage of a minute fraction of inoculum into the perivenous tissues of the tail. Bacterial multiplication occurred in such foci in irradiated (leucopenic) mice, but not in unirradiated mice, nor at the site of intraperitoneal inoculation even in irradiated mice.
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10038
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10039
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Fesel C, Coutinho A. Dynamics of serum IgM autoreactive repertoires following immunization: strain specificity, inheritance and association with autoimmune disease susceptibility. Eur J Immunol 1998; 28:3616-29. [PMID: 9842904 DOI: 10.1002/(sici)1521-4141(199811)28:11<3616::aid-immu3616>3.0.co;2-b] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Immunization of Lewis rats with myelin basic protein (MBP) in complete Freud's adjuvant (CFA) provokes experimental allergic encephalomyelitis (EAE). Here we compare, irrespective of antigen specificity, the structure and dynamics of serum IgM autoreactive repertoires following immunization with MBP/CFA in EAE-susceptible Lewis and relatively resistant Fischer rats. Prior to the appearance of clinical symptoms, Lewis rats developed a specific modification of serum IgM autoreactivities that, scored on other determinants than MBP itself, showed a prognostic association with EAE symptoms. Although comparable in their production of MBP-specific serum IgM and IgG antibodies, Fischer rats did not share these MBP/CFA-induced IgM autoreactivities of Lewis rats when immunized in the same manner. Moreover, while the Lewis-type repertoire reaction was specific for MBP/CFA alone, the respective Fischer reaction was not qualitatively different from that observed in this strain upon non-pathogenic immunization with self-related or -unrelated antigens. In general, the repertoire reactions differed qualitatively between the strains, consisting of components with typical behavior and strain preferences. The EAE-associated, as well as the other components of both Lewis- and Fischer-type repertoire reactions were usually co-dominantly inherited in F1 animals. These results indicate that a global antibody repertoire analysis may serve as a tool to describe prototypical response structures, possibly involved in immune regulation and susceptibility to pathogenic autoimmunity.
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10040
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Rich T, Grüneberg U, Trowsdale J. Heat shock proteins, HLA-DR and rheumatoid arthritis. Nat Med 1998; 4:1210-1. [PMID: 9809521 DOI: 10.1038/3172] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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10041
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Neff JA, Crawford SL. The Health Belief Model and HIV risk behaviours: a causal model analysis among Anglos, African-Americans and Mexican-Americans. ETHNICITY & HEALTH 1998; 3:283-299. [PMID: 10403110 DOI: 10.1080/13557858.1998.9961871] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A causal model of the Health Belief Model (HBM) is empirically evaluated which emphasizes possible indirect paths linking distal demographic and seriousness/susceptibility variables to HIV risk behaviours among Anglo, African-American, and Mexican-American adults. A specific focus of the paper is upon alcohol-related expectancies (anticipation of disinhibitory effects of alcohol upon sexual behavior) as a 'barrier' to preventive behaviours. Ethnic comparisons stem both from the paucity of available research on the HBM in minority populations and from recent questions regarding the applicability of rational models such as the HBM among minority groups. Analyses of data from a community sample of 1390 adults indicate relatively consistent direct effects of barriers for males and benefits for females upon HIV risk behaviors. The analyses suggest distinct paths operative among males and females. The susceptibility-barriers-risk behaviours path among males may suggest that alcohol-related expectancies (barriers in this model) may be more strongly related to risk behaviours among males than minority females.
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10042
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KANTOCH M, BANG FB. Conversion of genetic resistance of mammalian cells to susceptibility to a virus infection. Proc Natl Acad Sci U S A 1998; 48:1553-9. [PMID: 14453663 PMCID: PMC220997 DOI: 10.1073/pnas.48.9.1553] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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10043
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PLATT H. Phagocytic activity in squamous epithelia and its role in cellular susceptibility to foot-and-mouth disease. Nature 1998; 190:1075-6. [PMID: 13736278 DOI: 10.1038/1901075a0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10044
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SELLERS MI, LAVENDER JF. Studies on the interrelationship between the blood-brain barrier and entry of viruses into the central nervous system. I. The effect of carbon dioxide on type II poliovirus infection in mice. ACTA ACUST UNITED AC 1998; 115:107-30. [PMID: 13910469 PMCID: PMC2137472 DOI: 10.1084/jem.115.1.107] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Inhalation of elevated concentrations of CO2 produces a significant increase in the susceptibility of mice to intravenously inoculated Type II poliovirus. The CO2 effect is directly proportional to the concentration; 2.5 minutes inhalation of a mixture of 30 per cent CO2-70 per cent O2 produces maximal effects, while lower concentrations of CO2 require correspondingly longer periods. The threshold level is 7 per cent; inhalation of lower concentrations, even for long periods of time, fails to enhance virus infectivity. Placing the animals in the CO2 atmosphere before injection of virus does not influence susceptibility; virus must be in the circulation at the time CO2 is inhaled if enhancement of infectivity is to be elicited. The effect is completely reversible, disappearing almost immediately upon withdrawal of the animals from the CO2 atmosphere. CO2 mediates an increase in the entry of virus into the CNS from the circulation but does not affect the spread of virus within the CNS; susceptibility of mice to intracerebrally inoculated poliovirus is not influenced by CO2 inhalation. The mechanism(s) of action of CO2 can be explained, in part, by the dilatation of cerebral blood vessels and increased rate of blood flow through the CNS produced by the CO2. However, other factors, which remain unidentified, contribute to the net effect of CO2. The relationship between the mechanism of action of CO2 and the provoking effects of trauma and violent exercise in poliomyelitis is discussed. Also, a relationship between the CO2 tension of the blood and environmental temperatures on poliovirus susceptibility is proposed.
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10045
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Abstract
Using peritoneal macrophage cultures it was found that both PRI mice and their macrophages in culture were susceptible to mouse hepatitis virus and that C(3)H mice and macrophages were resistant. All F(1) macrophages and some back-cross cell cultures were susceptible. The degeneration of F(1) and back-cross macrophages obtained either from adult mouse peritoneal exudate or newborn mouse liver, occurred more slowly than PRI macrophages. Segregation of susceptibility occurred in the first back-cross generation. Tests of three back-cross generations from susceptible mice yielded about one-quarter of the mice shown to be susceptible either by direct test or test of their macrophages. A clear correlation between susceptibility in vivo and in vitro was established both in the test of the percentage segregation and in tests of individual back-cross mice. A small series of tests, however, indicated that 50 per cent of the back-cross mice had the genetic capacity to transmit susceptibility. Thus a hypothesis of two genes for susceptibility, although not excluded, may yield to a hypothesis of a single dominant gene, incompletely expressed. Resistant cells were converted into susceptible cells by ingestion of a relatively large particle containing a heat-stable substance. This susceptibility, although complete, was temporary. The nature of the factor causing the change has been discussed.
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10046
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BROOME JD. Evidence that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects. II. Lymphoma 6C3HED cells cultured in a medium devoid of L-asparagine lose their susceptibility to the effects of guinea pig serum in vivo. ACTA ACUST UNITED AC 1998; 118:121-48. [PMID: 14015822 PMCID: PMC2137577 DOI: 10.1084/jem.118.1.121] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Cells of the original line of lymphoma 6C3HED, which regularly prove susceptible to the effects of guinea pig serum in vivo, were cultured in Eagle's medium devoid of L-asparagine; after a latent period of 2 or more weeks, during which time the cell population declined markedly, some of the cells began to proliferate, and thereafter continued vigorous growth. On implantation into mice the proliferating cells were found, however, to have completely and permanently lost their susceptibility to the effects of guinea pig serum. By contrast, when cultures of the original line of 6C3HED cells were prepared in Eagle's medium to which L-asparagine was added in a concentration of 20.0 mg/liter or more, they proliferated vigorously from the beginning; after long periods of growth in the enriched medium in vitro they remained susceptible to the effects of guinea pig serum upon test in vivo. Other amino acids, purines, and pyrimidines were unable to substitute for L-asparagine in this relation. Furthermore, a variant subline of 6C3HED cells which had become insensitive to guinea pig serum under in vivo conditions did not require L-asparagine for growth in tissue culture. It seems plain from the findings as a whole, that in 6C3HED cells, L-asparagine dependence in vitro is associated with the in vivo character of guinea pig serum sensitivity, and conversely L-asparagine independent variants are insusceptible to the effects of guinea pig serum. The implications of the findings complement those of a companion paper in which direct evidence is provided that the L-asparaginase of guinea pig serum is responsible for its antilymphoma effects.
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10047
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GAINES S, TULLY JG, TIGERTT WD. Studies on infection and immunity in experimental typhoid fever. II. Susceptibility of recovered animals to re-exposure. ACTA ACUST UNITED AC 1998; 112:1023-36. [PMID: 13702954 PMCID: PMC2137315 DOI: 10.1084/jem.112.6.1023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Chimpanzees recovered from typhoid fever induced by ingestion of large numbers of phage-type T S. typhosa were rechallenged approximately a year and a half later with a like number of a phage-type E(1) strain. Control animals exhibited febrile responses, bacteriemia, and other significant laboratory and clinical findings, including increases in C-reactive protein levels and sedimentation rates. All of the previously infected and recovered chimpanzees were negative with respect to the aforementioned observations, and appeared to have resisted significant re-infection. On the other hand, recovery from typhoid fever induced by smaller numbers of S. typhosa failed to protect completely against rechallenge with larger numbers of these organisms. These findings indicate that chimpanzees recovered from typhoid fever may be protected against re-infection, even though the re-infecting organism is of a different phage type. Differences in the magnitude of the original and subsequent infecting inocula appear to influence the response to rechallenge.
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10048
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FINKELSTEIN RA. Alteration of susceptibility of embryonated eggs to Newcastle disease virus by Escherichia coli and endotoxin. Exp Biol Med (Maywood) 1998; 106:481-4. [PMID: 13699646 DOI: 10.3181/00379727-106-26376] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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10049
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SULKIN SE, KRUTZSCH PH, ALLEN R, WALLIS C. Studies on the pathogenesis of rabies in insectivorous bats. I. Role of brown adipose tissue. ACTA ACUST UNITED AC 1998; 110:369-88. [PMID: 13835624 PMCID: PMC2137008 DOI: 10.1084/jem.110.3.369] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Studies on the pathogenesis of rabies in two species of experimentally infected insectivorous Chiroptera, the Mexican free-tailed bat (Tadarida mexicana), a quasi hibernator, and the little brown bat (Myotis lucifugus), a deep hibernator, provided evidence that brown adipose tissue may serve as an extraneural site for storage and multiplication of rabies virus. Although the Mexican free-tailed bat proved to be relatively insusceptible to experimental rabies infection, virus was demonstrated in the brown fat of 22 per cent of those animals shown to be infected by viral assay in white Swiss mice. Rabies infection in this species was most evident 20 to 40 days after intramuscular inoculation of virus. Rabies virus was found to be widely distributed in the little brown myotis 9 to 26 days following inoculation and virus concentrations in some of the tissues approached the level of the stock mouse brain virus suspension used in inoculating these bats. The shorter incubation period and higher virus titers in the tissues assayed reflect the increased susceptibility of Myotis lucifugus as compared with the Mexican free-tailed bat. Virus was demonstrated in the brown fat of 30 per cent of the experimentally infected Myotis. In the experimentally infected Myotis lucifugus and in the Syrian hamster which is highly susceptible to rabies infection, rabies virus was isolated more frequently from the brown fat than from the salivary gland indicating that in a susceptible host brown adipose tissue may be as frequent a site of viral proliferation as salivary gland. Since rabies virus was found to persist for long periods of time in the brown fat of experimentally infected bats and was occasionally demonstrated in this tissue alone, it is suggested that brown adipose tissue provides a mechanism by which these animals may serve as reservoirs for this agent in nature. The possibility that similar mechanisms may be involved in the maintenance of other viral agents during interepidemic periods is discussed.
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10050
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Thompson-Snipes L, Skamene E, Radzioch D. Acquired resistance but not innate resistance to Mycobacterium bovis bacillus Calmette-Guérin is compromised by interleukin-12 ablation. Infect Immun 1998; 66:5268-74. [PMID: 9784532 PMCID: PMC108658 DOI: 10.1128/iai.66.11.5268-5274.1998] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Interleukin-12 (IL-12) is one of the first cytokines produced by macrophages, key mediators of innate resistance, during the host's immune response to infections. Therefore, in this study we propose that IL-12 has an important role in the early phase of the immune response to Mycobacterium bovis BCG. IL-12 has been shown to enhance the maturation of protective Th1 cells and gamma interferon (IFN-gamma) production during mycobacterial infection. Therefore, it may play a crucial role during the immune phase of infection as well. To examine the role of IL-12 in both the innate and the immune phase of infection, we compared BCG-resistant mice, B10.A (Bcgr), to the susceptible congenic strain B10.A (Bcgs) following administration of a blocking monoclonal antibody to IL-12 (10F6). Anti-IL-12-treated susceptible animals exhibited a two- to threefold increase in spleen CFU by day 21. In contrast, anti-IL-12 treatment had little or no effect on the response of the genetically resistant animals to infection. The B10.A (Bcgr) but not the B10.A (Bcgs) mice had an increase in IFN-gamma mRNA relative to baseline levels as early as day 1 of infection irrespective of anti-IL-12 treatment. By day 14, B10.A (Bcgr) mice showed a decrease in IFN-gamma mRNA while the B10.A (Bcgs) mice showed a significant increase in IFN-gamma mRNA levels. Thus, during BCG infection, the B10.A (Bcgr) mice mount an early IFN-gamma response against BCG whereas the B10.A (Bcgs) mice have a delayed IFN-gamma response correlating with their genetic permissiveness expressed as an increased mycobacterial load by day 21. Overall, our data demonstrate that the inherent resistance of B10.A (Bcgr) mice to mycobacteria does not depend on optimal levels of IL-12 to maintain effective control of the bacteria, whereas IL-12 is important for the susceptible animals' response to BCG during the peak of infection.
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