Cytokines and soluble cytokine receptor induction after IL-12 administration in cancer patients.

This study shows that subcutaneous administration of increasing doses of IL-12, once a week, in 21 cancer patients increased the expression of cytokine genes (interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), IP-10, MIG, IL-10, IL-4) in peripheral blood mononuclear cells even at very low doses (30 ng/kg). Surprisingly, no circulating TNF-alpha or IL-4 could be detected in the plasma of patients treated with IL-12. However, a marked increase of soluble IL-4 receptor was demonstrated in the plasma of five of the six patients studied, which may represent an additional mechanism by which IL-12 inhibits the development of the Th2 response in vivo. A marked decline of IFN-gamma and IP10 induction was recorded after repeated cycles of IL-12. In contrast, in most patients IL-12 increased IL-10 expression with no subsequent decrease during the course of therapy, and even an earlier peak of IL-10 induction at the 6th cycle. In addition, a constant up-regulation of serum soluble IFN-gamma receptor levels was observed after each cycle of IL-12 treatment with a delayed peak compared with the IFN-gamma peak. The constant rise of IL-10 and soluble IFN-gamma receptor during IL-12 therapy may therefore contribute to the inhibition of IFN-gamma activity detected after repeated cycles of IL-12. Lastly, a marked heterogeneity of cytokine induction was observed from one patient to another, which appeared to be independent of the dose of IL-12 administered. These data may lead to a better understanding of the biological activity of IL-12 and the in vivo mechanisms of its regulation.

Enhancement by O6-benzyl-N2-acetylguanosine of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea therapeutic index on nude mice bearing resistant human melanoma.

The exposure of cells to O6-benzyl-N2-acetylguanosine (BNAG) and several guanine derivatives is known to reduce the activity of O6-alkylguanine-DNA alkyltransferase (MGMT) and to enhance the sensitivity of Mer+ (methyl enzyme repair positive) tumour cells to chloroethylnitrosoureas (CENUs) in vitro and in vivo. High water solubility and the pharmacokinetic properties of BNAG make it a candidate for simultaneous administration with CENUs by the i.v. route in human clinical use. In vivo we have shown previously that BNAG significantly increases the efficiency of N'-[2-chloroethyl]-N-[2-(methylsulphonyl)ethyl]-N'-nitrosourea (cystemustine) against M4Beu melanoma cells (Mer+) through its cytostatic activity by the i.p. route, but also increases its toxicity. To investigate the toxicity of BNAG and cystemustine when administered simultaneously in mice, we compared the maximum tolerated dose and LD50 doses of cystemustine alone or in combination with 40 mg kg(-1) BNAG by the i.p. route. The toxicity of cystemustine was enhanced by a factor of almost 1.44 when combined with BNAG. To compare the therapeutic index of cystemustine alone and the cystemustine/BNAG combination, pharmacological tests were carried out in nude mice bearing Mer+ M4Beu human melanoma cells. Isotoxic doses were calculated using the 1.44 ratio. The treatments were administered three times by the i.v. route on days 1, 5 and 9 after s.c. inoculation of tumour cells. Although the toxicities of the treatments were equal, BNAG strongly enhanced tumour growth inhibition. These results demonstrate the increase of the therapeutic index of cystemustine by BNAG and justify the use of BNAG to enhance nitrosourea efficiency in vivo by i.v. co-injection.

Enhancement by O6-benzyl-N-acetylguanosine derivatives of chloroethylnitrosourea antitumor action in chloroethylnitrosourea-resistant human malignant melanocytes.

The exposure of cells to O6-methylguanine or O6-benzylguanine is known to reduce the enzymatic activity of O6-alkylguanine-DNA alkyltransferase, which leads to a sensitivity enhancement to chloroethylnitrosourea cytotoxic effects. The main disadvantage of the guanine derivatives is their low water solubility, which makes their formulation difficult for clinical use in humans. To overcome this problem, water-soluble O6-alkylguanine-DNA alkyltransferase inhibitors have been synthesized and their ability to increase the chloroethylnitrosourea potency in vitro and in vivo was evaluated. Four water-soluble molecules (O6-methyl-N-acetylguanosine; O6-methyl-N-acetyldeoxyguanosine; O6-benzyl-N-acetylguanosine, BNAG; and O6-benzyl-N-acetyldeoxyguanosine, BNADG) were tested for sensitivity of M4Beu cells to N'-(2-chloroethyl]-N[2-(methylsulfonyl)ethyl]-N'-nitrosourea (cystemustine) based on the colony-forming ability of M4Beu melanoma cells. The cell sensitivity to cystemustine was increased by benzylated derivative pretreatment but not with methylated derivative pretreatment. Furthermore, BNAG or BNADG pretreatment followed by cystemustine was less cytotoxic than BNAG or BNADG given simultaneously and followed 24 hr later by BNAG or BNADG. Comparative studies performed with O6-benzylguanine on the same model showed that this inhibitor was effective at lower concentrations than the corresponding guanosine or deoxyguanosine analogs. Preliminary pharmacological assays were carried out in nude mice bearing the M4Beu tumor to determine whether the BNAG-cystemustine combination has greater antitumor activity than cystemustine alone. Simultaneous i.p. injection of 200 mg/kg of BNAG and 15 mg/kg of cystemustine followed by an i.p. injection 4 hr later of 200 mg/kg of BNAG led to a significant enhancement of inhibition of tumor growth.

Disposition of stiripentol in the pregnant and non-pregnant female rat.

1. The disposition of stiripentol labelled with 14C and 3H on two positions has been studied in the pregnant and non-pregnant female rat after p.o. administration of a 200 mg/kg dose. 2. For both labelled species radioactivity was eliminated mainly in the faeces (69% within 72 h). Urinary excretion was rather low (22% within 72 h). No significant difference was found between the disposition of the two labelled species. 3. For both labelled species concentrations of radioactivity reached a plateau in the plasma and tissues between 1 and 6 h after administration. The liver, fat, mammary gland and adrenal gland were the most extensively-labelled organs. The affinity for the mammary gland was significantly greater in pregnant rats and for the adrenal gland was significantly greater in the non-pregnant rats. The fact that the concentration in the placenta was higher than in the foetus demonstrated that this membrane acts as a barrier for the penetration of the drug in the amniotic fluid. 4. Chromatographic analysis of the faeces and urine showed that an important portion of the dose remained unabsorbed through the gastrointestinal tract. The absorbed fraction undergoes an extensive first-pass metabolism involving mainly the oxidative cleavage of the methylenedioxy ring. Comparison with the results of other work conducted on the non-pregnant rat demonstrated that pregnancy did not affect the disposition and metabolic process.

Susceptibility to murine hepatitis virus (type 3)-induced paralysis is influenced by class I genes of the MHC.

Using H-2 recombinant congenic strains of mice, genetic analysis of resistance to murine hepatitis virus type 3 (MHV3)-induced paralysis was performed. It appeared that both H-2K and H-2D, two class I gene regions of the mouse major histocompatibility complex (MHC), can play independent significant roles in the establishment of such resistance.

Thymic epithelial cell transplantation in patients with acquired immunodeficiency syndrome. Evidence for infection by HIV-I of newly differentiated T cells at the site of transplantation.

From October 1983 to July 1984, 11 adult AIDS patients have received single or repeated thymic grafts. All have had opportunistic infections and 3 also had Kaposi's sarcoma. Thymic tissue from infants undergoing cardiac surgery was cultured to provide a thymocyte- and fibroblast-free epithelial cell inoculum. 18-21 days post-explantation, cells and explants were injected intraperitoneally, intramuscularly or intrahepatically. Transplants were well tolerated in all cases. In 7 cases liver biopsy was performed at the time of grafting and 2 months later. Ten patients have died after a mean survival time following transplantation of 8.7 months while 1 patient was lost to follow up. Clinical improvement and absence of new opportunistic infections were apparent for 4 months following transplantation. Partial immunoreconstitution was evidenced by an increase in peripheral blood lymphocytes (8 of 10 cases) and lymphocyte subsets (7 of 10 cases) as well as by presence of T4 and T8 positive cells in the liver (5 of 7 cases). In 5 of 7 patients, double-staining immunofluorescence showed that HIV-I antigens were present in T4-phenotype cells, at the site of the graft, 2 months after grafting, but were not detected in the liver at the time of grafting. Transient immunoreconstitution, therefore, maybe related to destruction of newly differentiated T lymphocytes.

Lag between discovery and production of new vaccines for the developing world.

Communicable diseases represent a considerable burden in terms of suffering and costs. The decision to develop a new vaccine varies with perspectives. The public health perspective is influenced largely by cost-benefit ratios; the community perspective by a strong desire to alleviate suffering and disability from disease and from vaccine side-effects; and that of vaccine producers by demand, technological feasibility of development, and anticipated return on investment. Each of these perspectives is important. However, they often are mutually exclusive. From a humanitarian and epidemiological perspective, the most urgent needs related to communicable diseases are those of the poorest countries; in the industrialised world, with the exception of the vaccine for the acquired immunodeficiency syndrome (AIDS), public health priorities, evaluated in terms of the cost-benefit ratio, often differ from those of the market, which usually selects its priorities according to return on investment. The six vaccines used in the Expanded Programme of Immunisation (EPI) are offered cheaply through a highly efficient bidding system. It would have to be extended, under the same form or differently, to other vaccines, such as those for rabies, hepatitis B, or japanese encephalitis. For vaccines that are being developed, such as conjugated polysaccharide or acellular pertussis vaccines, it is difficult to foresee how these expensive vaccines can be distributed. The situation is even worse for vaccines to be developed specifically for the third world. To make these vaccines available to everyone there must be technology that enables producers to sharply reduce production costs, and a subsidy for research and development and production.

Anti-HIV antibodies and other serological and immunological parameters among normal Haitians in Montreal.

A matched-pair, cross-sectional study of lymphocyte and serological parameters associated with acquired immune deficiency syndrome (AIDS) in 189 randomly chosen, ostensibly healthy adult Haitian immigrants residing in Montreal matched for sex, age (within 5 years), and neighborhood of residence to 189 non-Haitian (Caucasian) controls was done in 1983-1984. Three years later (1986-1987), 41 of the Haitian study subjects and 83 of the non-Haitian controls participated in a follow-up study centered on lymphocyte parameters. A significantly greater number of Haitians than controls had produced antibodies to Toxoplasma gondii. In addition, a greater percentage of the Haitians than the controls were also producing antibodies to two other opportunistic pathogens frequently encountered in AIDS, cytomegalovirus and hepatitis B virus, implying that the Haitians in general had had greater exposure to a variety of infectious agents than had the controls. A few study participants were producing antibodies against two viruses that are related to the human immunodeficiency virus-type 1 (HIV-1), the human T-cell lymphotropic viruses I and II (HTLV-I and -II). Two Haitians and one control were producing antibodies against HTLV-I. One study subject and four controls were HTLV-II seropositive. The most interesting and surprising finding was that four (2.1%) of the Haitian study subjects but none of the controls were seropositive for HIV-1. These individuals, two of whom were women and two men, were asymptomatic. Although their individual lymphocyte parameter values fell in the normal range, as a group they had statistically significantly lower average values for their lymphocyte parameters than did the HIV-seronegative Haitian study objects.(ABSTRACT TRUNCATED AT 250 WORDS)

A retrospective and prospective study of the number of kidney transplants in 31 countries.

The aim of the present study was to try to predict the number of cadaveric kidney transplantations (CKT) that will be performed in the year 1993. The raw data regarding the number of renal transplants that have been performed annually since 1975 in 31 countries, which were divided into six groups, were collected from published reports and confirmed by a questionnaire sent to all centers. The annual number of grafts was estimated using an exponential model, highly correlated with retrospective data (r2 greater than 0.99). Predictions for 1993 were extrapolated. The growth of transplantation activity is limited by a shortage of available donor organs. The maximum number of grafts was arbitrarily set at 40 per million population, which is the maximum rate currently observed. The total number of CKT carried out between 1975 and 1986 was 114,000; this will probably exceed 280,000 in 1993. The yearly activity in 1987 exceeded 16,500 and is expected to reach approximatively 26,000 grafts in 1993.

Host cell resistance to mouse hepatitis virus type 3 is expressed in vitro in macrophages and lymphocytes.

Phenotypic expression of in vivo sensitivity to mouse hepatitis virus type 3 (MHV3) was studied in vitro in macrophages and lymphocytes. MHV3 infections were induced in peritoneal exudate (PE), nonadherent spleen (NAS) and thymus (THY) cells from resistant A/J, susceptible C57BL/6 or semisusceptible (C57BL/6xA/J)F1 mice. Differences in cytopathic effect, cell viability and virus titers were found only at 48 hrs postinfection (p.i.). "Carrier state" infections were performed at 48 hrs p.i. by transfer of supernatants of infected cells to newly collected cells originating from the same strain of mice. A passage-dependent restriction of viral replication was detected in vitro and was expressed in PE, NAS and THY cells as a recessive phenotype. No defective-interfering viral particles were involved in the restriction of viral replication. Results obtained with crossed infections and determination of the number of productively infected cells demonstrated that restriction of viral replication in macrophages and lymphoid cells from resistant A/J mice is controlled by a genetically-determined intrinsic cellular mechanism acting principally on the level of production of infectious viral particles by the infected cell.

Pathogenicity of HIV in lymphatic organs of patients with AIDS.

HIV antigens were searched for in the thymus, lymph nodes, bone marrow, and spleen of AIDS patients, by means of immunofluorescence technique. Human IgG against HIV and monoclonal antibodies against viral gag P24 protein yielded strong cytoplasmic fluorescence of cells in sections of the thymus, lymph nodes and spleen. Some cells containing HIV antigens were morphologically multinucleated giant cells. They reacted with monoclonal antibodies against helper/inducer T-cells (OKT4+), and were complexed with antibody or with complement as demonstrated by double-staining immunofluorescence technique. A large number of inflammatory cells infiltrated the thymus in areas containing cells expressing HIV antigens. These studies demonstrated an association of HIV virus with cytopathic and immunopathogenic reactions in lymphatic organs of AIDS patients, and are consistent with previous results, as well as indicative of a primary aetiologic role for the virus.

Thymic epithelium in AIDS. An immunohistologic study.

The authors investigated by immunofluorescence the thymic epithelium from AIDS patients, using several structural and functional markers of this tissue. In AIDS thymus, the epithelial reticular pattern was lost; and instead, clusters of round or spindle-shaped cells (assessed by their keratin content) were found. In addition, regions of epithelial necrosis, with loss of cell limits, were frequently observed. Thymulin content was decreased, and a partial loss of differentiation antigens of the thymic epithelium was also detected. The authors showed the presence of immunoglobulins and elements of the complement system directly bound to AIDS thymic epithelium, but not in any of the controls studied, including thymuses from patients who died after a long period of agony. These data suggest that the thymic epithelium can be included among the target tissues in AIDS, possibly by an indirect mechanism of autoimmune destruction.

Immunologic findings in healthy Haitians in Montreal.

To investigate the occurrence of acquired immune deficiency syndrome in Haitians, a health status questionnaire was administered and selected studies of immune status done in a randomly chosen sample of 189 healthy adult Haitians living in Montreal. The study group was comparable to a large sample of Haitians in Montreal interviewed in the 1981 census with respect to age, sex, number of persons per household and year of immigration, but the proportion of currently married people in the study was larger (60.8% v. 42.6%). The results in the study group were compared with those in a sample of 189 non-Haitians matched for age, sex and neighbourhood of residence. Persons with known causes of impaired immune function were excluded. The participation rate was 87.5%. The study and control groups both reported few symptoms and chronic health problems and had comparable demographic data, including rate of employment and income. The mean total numbers of lymphocytes, OKT3 and OKT4 (helper) and OKT8 (suppressor) cells were significantly higher in the Haitians than in the controls, though still within normal limits. There was a borderline elevation of the lymphocyte response to phytohemagglutinin in the Haitians. The ratios of helper to suppressor T cells in the two groups were, however, not significantly different. The Haitians, in comparison with non-Haitians living in the same community, had no demonstrable abnormalities of cellular immune function.