RESUMEN
OBJECTIVES: This study assessed recent trends in HIV seroprevalence among injecting drug users in New York City. METHODS: We analyzed temporal trends in HIV seroprevalence from 1991 through 1996 in 5 studies of injecting drug users recruited from a detoxification program, a methadone maintenance program, research storefronts in the Lower East Side and Harlem areas, and a citywide network of sexually transmitted disease clinics. A total of 11,334 serum samples were tested. RESULTS: From 1991 through 1996, HIV seroprevalence declined substantially among subjects in all 5 studies: from 53% to 36% in the detoxification program, from 45% to 29% in the methadone program, from 44% to 22% at the Lower East Side storefront, from 48% to 21% at the Harlem storefront, and from 30% to 21% in the sexually transmitted disease clinics (all P < .002 by chi 2 tests for trend). CONCLUSIONS: The reductions in HIV seroprevalence seen among injecting drug users in New York City from 1991 through 1996 indicate a new phase in this large HIV epidemic. Potential explanatory factors include the loss of HIV-seropositive individuals through disability and death and lower rates of risk behavior leading to low HIV incidence.
Asunto(s)
Seroprevalencia de VIH/tendencias , Abuso de Sustancias por Vía Intravenosa/complicaciones , Salud Urbana/tendencias , Adulto , Femenino , Conductas Relacionadas con la Salud , Humanos , Masculino , Ciudad de Nueva York/epidemiología , Oportunidad Relativa , Vigilancia de la Población , Grupos Raciales , Factores de Riesgo , Asunción de RiesgosRESUMEN
Various injection schedules of C. parvum and tumor cells of the nitrosourea-induced malignant neurinoma, TR-481, were used to induce tumor immunity in syngeneic CDF rats. Although subcutaneous injection of the poorly immunogenic TR-481 cells alone or with C. parvum caused retardation of growth of 2 x 10(5) TR-481 cells injected 1-3 weeks later, no significant difference in tumor size or incidence was obtained, as judged by tumor growth at 8 weeks. In contrast, injection of TR-481 with C. parvum into C. parvum-presensitized rats caused a more significant degree of tumor immunity with complete inhibition of the challenge tumor growth in 17-33% of the animals. Repeated subcutaneous injection of gamma-irradiated TR-481 tumor cells mixed with C. parvum also proved effective, resulting in absence of tumor growth in 40% of the rats. Tumor immunity was specific, since growth of an unrelated tumor was unaffected. It is suggested that local immunological reactivity to C. parvum in the immunizing tumor promotes development of specific tumor immunity.
Asunto(s)
Adyuvantes Inmunológicos , Neoplasias Encefálicas/inmunología , Inmunización , Compuestos de Nitrosourea , Propionibacterium acnes/inmunología , Animales , Neoplasias Encefálicas/inducido químicamente , Femenino , Inmunidad , Trasplante de Neoplasias , Neoplasias Experimentales/inducido químicamente , Neoplasias Experimentales/inmunología , Neurilemoma/inducido químicamente , Neurilemoma/inmunología , Ratas , Ratas Endogámicas F344Asunto(s)
Encéfalo/metabolismo , Metacualona/metabolismo , Animales , Masculino , Ratas , Factores de TiempoRESUMEN
Tubules were isolated by the passage of coarsely homogenized kidney parenchyma through a series of stainless steel sieves of varying pore sizes. The isolated tubules, which were free of glomeruli or any contaminating tissue, based on light microscopic examination, served as starting material for the isolation of tubular basement membrane (TBM). The tubules were sonically disrupted, and the subsequent isolation procedure was conceptually similar to that of the isolation of glomerular basement membrane (GBM). The chemical composition of TBM was compared to that of GBM and collagen. 3-hydroxyproline, a marker for basement membrane protein, was present in higher amount in TBM (10 residues per 1,000 amino acid residues) than in GBM (7 residues per 1,000). Glycine and hydroxylysine content was also higher in TBM (255 and 27 residues per 1,000, respectively, in contrast to 204 and 18 residues in GBM). The total carbohydrate content was 7.6 mg per 100 mg of dry weight (neutral sugars, 6.3; GlcN, 0.9; GalN, 0.1; and sialic acid, 0.3). By electron microscopic examination, the isolated TBM was similar to GBM, except for greater variability in diameter and serrated appearance of one surface of the tubular basement membrane fragments. The method is suitable for the isolation of TBM in sufficient quantity for subsequent chemical analyses and immunologic studies.
Asunto(s)
Túbulos Renales , Animales , Membrana Basal , Metabolismo de los Hidratos de Carbono , Colágeno/metabolismo , Glicina/metabolismo , Hidroxilisina/metabolismo , Hidroxiprolina/metabolismo , Glomérulos Renales/metabolismo , Glomérulos Renales/ultraestructura , Túbulos Renales/metabolismo , Túbulos Renales/ultraestructura , Proteínas de la Membrana/metabolismo , Ratas , Extractos de TejidosRESUMEN
Investigations on the spontaneous release of 51Cr from the EL-4 ascitic lymphoma showed that daily rhythmic changes can be correlated with the dominance of certain cell types in the population. A generation time of 9.8 h, an average doubling time of 32 h, and an 'appearance cycle' of 96 h were established for the population. Earlier observed variations in the values for spontaneous 51Cr release can be explained in terms of the cellular composition of the population.