[Treatment with enoxaparin adapted to the fertility programs in women with recurrent abortion and thrombophilia]

Acquired and inherited thrombophilia are associated with recurrent pregnancy loss (RPL). Antithrombotic therapy could restore hemostatic balance and improve early placentation and gestational outcome. We evaluated the efficacy of enoxaparin adapted to the fertility program for prevention of pregnancy loss in 35 women (W) with early RPL and thrombophilia. Previous to the diagnosis of thrombophilia, they had had a total of 105 gestations of which 89 (85%) ended in early pregnancy loss. After diagnosis of thrombophilia, 35 subsequent pregnancies were treated with enoxaparin. In 5 cases assisted reproductive techniques were necessary to achieve pregnancy due to couple infertility. In 17 W who had had at least one preclinical pregnancy loss, enoxaparin (20 mg/d/s.c.) was started previous to conception and adapted to the fertility program. All the women continued with the gestational regime. Eighteen W with only clinical pregnancy loss started enoxaparin (20 mg twice per day s.c.) after biochemical pregnancy diagnosis. During gestations heparin dose was adjusted with anti Xa test, maintaining a range between 0.3 at 0.6 u/ml. With antithrombotic therapy, 30/35 (85%) of the pregnancies ended in live birth versus 16/105 (15%) of the pregnancies without treatment (p < 0.001). These results suggest that enoxaparin adapted to the fertility program can be effective in the prevention of preclinical and clinical abortion in women with thrombophilia.

Plasma and cerebrospinal fluid leptin levels are maintained despite enhanced food intake in progesterone-treated rats

OBJECTIVES

For adipostatic control, increases in food intake are followed by increased leptin levels that in turn reduce food intake. However, progesterone administration increases both food intake and body weight. The aim of this study was to analyze changes in the white adipose tissue-leptin system in rats with enhanced plasma levels of progesterone.

METHODS

Female Wistar rats received progesterone chronically by means of subcutaneous implants over 30 days.

RESULTS

They showed an increased food intake followed by increased body weight and heavier fat depots. An enhanced ob-mRNA level was detected in inguinal white adipose tissue depot on day 2 of treatment but the increase was transient, disappearing on day 6 of treatment. No changes in ob-mRNA levels were found in parametrial and retroperitoneal white adipose tissue depots. Plasma and cerebrospinal fluid leptin levels were unchanged either during the treatment or between corresponding treated and control rats. Leptin concentrations in cerebrospinal fluid were ten times lower than in plasma (0.2--0.3 ng/ml versus 2--3 ng/ml respectively).

CONCLUSIONS

These results indicated that progesterone favours a positive energy balance not only by enhancing food intake but also by inhibiting the concurrent enhancement in plasma and cerebrospinal fluid leptin levels expected from the increased fat mass.

Rotavirus genotypes P[4]G9, P[6]G9, and P[8]G9 in hospitalized children with acute gastroenteritis in Rio de Janeiro, Brazil

Fifty-three rotavirus-positive fecal specimens from children with diarrhea admitted to a Rio de Janeiro, Brazil, children's hospital between January 1997 and December 1998 were characterized for P and G types by using reverse transcription-PCR. Genotype P[4]G2 accounted for 21% of isolates, while uncommon genotypes P[8]G9, P[6]G9, and P[4]G9 accounted for 13% of the isolates.

Enrichment of memory T cells and other profound immunological changes in the bone marrow from untreated breast cancer patients

Previous studies with animal tumors showed that bone marrow (BM) is a privileged site where potentially lethal tumor cells are controlled in a dormant state by the immune system. Here, we investigated BM of breast cancer patients with respect to tumor cell content, immune activation status and memory T-cell content. BM-derived cells from primary operated breast cancer patients (n = 90) were compared with those from healthy donors (n = 10) and also with cells from respective blood samples. Cytokeratin 19-positive tumor cells were detected by nested polymerase chain reaction. Three-color flow cytometry was used to identify numbers and activation state of T cells, natural killer (NK) cells, monocytes/macrophages and subsets by a panel of monoclonal antibodies (mAbs). The proportion of memory T cells among the CD4 and CD8 T cells was much higher in BM of cancer patients than in healthy donors (p < 0.001). The extent of memory T-cell increase was related to the size of the primary tumor. Patient-derived BM memory CD8 T cells could be shown to contain specific HLA-A2/Her-2/neu(369-377) tetramer binding cells. Patients with disseminated tumor cells in their BM had more memory CD4 T cells and more CD56(+) CD8(+) cells than patients with tumor cell-negative BM. Only some of the immunological changes seen in BM samples of cancer patients were also detectable in peripheral blood samples. Our hypothesis that BM is a special compartment for immunological memory and tumor dormancy is supported by the above findings. The overall results reveal that BM is a valuable additional compartment for immune diagnosis in pathological conditions and possibly for follow-up treatment strategies.

[Hypofibrinolysis and other hemostatic defects in women with antecedents of early reproductive failure]

The fibrinolytic system is involved in blood clot lysis and in other biological processes that require extracellular proteolysis such as ovulation, blastocyst implantation and trophoblastic invasion. An impaired fibrinolytic capacity is a common feature in women suffering from unexplained early recurrent pregnancy loss. We carried out a prospective study with 114 patients. Three groups were established: Group 1: women who had two or more unexplained miscarriages of < 12 weeks of gestation (n = 52). Group 2: women who had 2 or more embryo-implantation failure after embryo-transfer with good quality embryos in assisted reproduction (n = 46). Group 3: women who had 2 or more embryo-implantation failure after embryo-transfer and one early loss of a pregnancy achieved in a cycle of assisted reproduction (n = 16). Fibrinolytic pattern pre and post-occlusion test was carried out: ECLT, PAI-1i, PAI-1b, t-PAi, t-PAb. In addition other studies were performed: LAC, ACA IgG and IgM, fibrinogen, factor XII, APCR. A high prevalence of thrombophilic defects and hypofibrinolysis was observed in the three groups. The fibrinolytic pattern was similar in the three groups, although a prolonged pre occlusion ECLT was more frequent in women with primary infertility (Group 2). Isolated hypofibrinolysis was found in 50% of the patients. The remaining patients with hypofibrinolysis presented combined defects with LAC, ACA and abnormal APCR. The fibrinolytic pattern in women with or without antiphospholipid antibodies was similar, although an elevated pre occlusion PAI-1i was more common in women without antiphospholipid antibodies. High prevalence of fibrinolytic abnormalities observed in women with unexplained early recurrent pregnancy loss and in women with repeated failure implantation after embryo-transfer in assisted reproduction, suggests that hypofibrinolysis could be a parameter of early reproductive failure.

Clinical and radiological improvement of periodontal disease in patients with type 2 diabetes mellitus treated with alendronate: a randomized, placebo-controlled trial

BACKGROUND

Alendronate (ALN) is an aminobisphosphonate commonly used for osteoporosis in postmenopausal women. We studied the effect of ALN on bone loss prevention in type 2 diabetes mellitus patients with periodontal disease.

METHODS

In a controlled double-blind, randomized study we evaluated prospectively diabetic patients paired by gender and years since diagnosis for 6 months. The study included 40 patients (20 men and 20 women), 50 to 60 years old, with more than 5 years since diagnosis of diabetes and established periodontitis. They were randomly allocated to alendronate (10 mg/daily) or placebo treatment for 6 months. The endpoints of treatment were: the distance between the alveolar bone border and the cemento-enamel-junction (CEJ) evaluated by means of digital radiographic imaging, a biochemical marker of bone resorption (urine N-telopeptide) (Ntx), and periodontal parameters. Metabolic control was assessed at baseline and after 6 months.

RESULTS

Baseline and 6-month glycated hemoglobin levels were similar in both groups. Alendronate induced a significant decrease in NTx at 6 months (P = 0.006). Periodontal parameters improved in both groups. However, they were significantly better for the ALN treated group. Alveolar bone border-CEJ distance increased in the placebo, but decreased in the ALN group (P = 0.0003).

CONCLUSIONS

In type-2 diabetic patients, alendronate induced more improvement in alveolar bone crest height than control therapy. No differences in urinary N-telopeptide or glycated hemoglobin were observed in this short-term randomized controlled pilot trial.

Dissection of tumor and host cells from metastasized organs for testing gene expression directly ex vivo

The interaction between tumor and host cells determines to a large extent the outcome, namely tumor growth and progression toward metastases or tumor arrest, dormancy, or rejection. Most of the studies published so far on interactions of tumor cells and host cells were made in vitro and dealt with aspects such as cell adhesion, proliferation, invasiveness, cytotoxicity, or cytokine production. As the microenvironment in tissue culture differs in many respects from that in vivo, new approaches for in vivo studies of tumor-host cell interactions is of utmost importance in cancer research. To elucidate the metastatic phenotype, approaches have been made to relate, for instance, cell surface molecules expressed on the tumor cell lines from tissue culture to their propensity to generate metastases in vivo (1). Several authors have reported that certain steps of the metastatic cascade are rate limiting (2-6). To produce metastases, tumor cells must complete each of the sequential steps in the pathogenesis of cancer metastasis. Each discrete step appears to depend on the interaction between tumor cells and multiple host factors (i.e., the microenvironment of the tumor) and to be regulated by transient or permanent changes in multiple genes at the level of DNA, RNA, or protein. On this background, the need for comprehensive in vivo/ex vivo studies on tumor-host interactions and their kinetics in relevant model systems becomes obvious.

Breaking tolerance to a tumor-associated viral superantigen as a basis for graft-versus-leukemia reactivity

A major goal in tumor immunotherapy consists of breaking potential tumor-specific T-cell unresponsiveness (tolerance), which may explain tumor growth in cancer patients. We report that immunological tolerance to a tumor-associated viral superantigen (SAg) is overcome in a mouse lymphoma model by transfer of allogeneic T cells expressing SAg-reactive Vbeta6 T-cell receptor chains. Surprisingly, upon contact with SAg-expressing lymphoma cells, Vbeta6 T cells became activated rather than tolerized (as reported previously). They also developed SAg-specific cytotoxic T-lymphocyte activity and secreted IL-2 and IFN-gamma. The grafted T cells infiltrated liver metastases, formed close contact with SAg-expressing tumor cells, and caused significant graft-vs. -leukemia (GvL) effects. Selection for tumor resistance among the progeny from a cross between SAg-negative donor and SAg- positive recipient strains revealed a strict correlation between loss of the endogenous SAg tolerogen, rescue of Vbeta6 T cells from SAg-mediated deletion, and leukemia resistance. These findings suggest that immune responses to SAg can be exploited to break tolerance and augment immune responses to tumors.

Glutathione is a factor of resistance of Jurkat leukemia cells to nitric oxide-mediated apoptosis

We have previously reported that nitric oxide (NO) stimulates apoptosis in different human neoplastic lymphoid cell lines through mitochondrial damage (including degradation of cardiolipin, a major mitochondrial lipid) followed by activation of caspases. Here we demonstrate that Jurkat human leukemia cells which survive after 24 h treatment with NO form subpopulations with higher and lower cardiolipin content (designated as NAO(high) and NAO(low), respectively). Sorted NAO(high) cells were found to survive in culture whereas sorted NAO(low) cells died. Moreover, NAO(high) cells acquired an increased resistance to the exposure to NO donors which remained unchanged during long-term culture. These cells showed a similar cardiolipin content and expressed the same level of anti-apoptotic proteins Bcl-2 and Bcl-x(L) as APO-S unsorted cells but contained significantly higher concentration of the antioxidant glutathione. Depletion of glutathione in these cells with buthionine-sulfoximine (BSO) correlated with a significant stimulation of NO-mediated apoptosis whereas the exposure of NO-sensitive APO-S cells to the glutathione precursor N-acetylcysteine (NAC) resulted in a substantial suppression of this effect. Our data suggest a complex mechanism of the resistence to NO-induced apoptosis in Jurkat human leukemia cells in which glutathione plays an important role.

Functional and in situ evidence for nitric oxide production driven by CD40-CD40L interactions in graft-versus-leukemia reactivity

In a murine tumor model, complete tumor remission is achievable at even advanced metastasized stages by transfer of immune T cells from donor B10.D2 (H-2d, Mls(b)) into tumor-bearing DBA/2 (H-2d, Mls(a)) mice. We showed previously that this graft-versus-leukemia (GvL) effect is dependent on synergistic interactions of transferred CD4+ and CD8+ T cells with host sialoadhesin (SER)-positive macrophages. We now show that the CD40-CD40L (CD154) interaction is involved in the induction of inducible nitric oxide synthase (iNOS) expression during adoptive immunotherapy (ADI). We demonstrate that during ADI, the level of CD40 expression in the liver becomes significantly augmented in comparison to livers of tumor-bearing, untreated animals. CD40 expression is found mostly on SER+ macrophages and to a lesser extent on dendritic cells (DCs). In GvL animals, more SER+ macrophages express iNOS than untreated animals. iNOS expressing cells are found in close proximity to apoptotic cells, at early time points of the therapy in areas of metastasis, and at late stages around portal veins, where CD4+ and CD8+ T lymphocytes form clusters with SER+ macrophages. Blocking of CD40L in vivo at days 5 and 20, when all iNOS+ cells express CD40, leads to significantly reduced CD40 and iNOS expression as well as to a marked inhibition of the therapeutic effect. These data provide functional and in situ evidence that the increased CD40 and iNOS expression observed during ADI contribute to the eradication of liver metastases and to the clearance of donor lymphocytes from the liver.

A unified framework for data modeling on medical information systems

Medical Information Systems (MIS) are seen as a way of optimizing the use of existing health-care infrastructure, without resorting to new and costly hospital (re)construction. The qualitative (re)design of such an environment requires a basic understanding of patient and doctors related characteristics and capabilities. Patient care, patient education, medical education, and clinical research need to be considered to meet the basic requirements on the level of services desirable, determined on the basis of the patient's length of stay; i.e., used for modeling the significant entities of such a world. The aim is to extract conclusions for the level of services provided to the users. One's concept will capture, as well as will integrate, the basic design principles under which MIS may be set.

Nitric oxide-mediated apoptosis in human breast cancer cells requires changes in mitochondrial functions and is independent of CD95 (APO-1/Fas)

We have previously shown that nitric oxide (NO) induces apoptosis in different human neoplastic lymphoid cells through caspase activation. Here we studied the NO-mediated apoptosis in human breast cancer cell lines derived from primary tumor (BT-20) or from metastasis (MCF-7). NO donor glycerol trinitrate (GTN) induced apoptosis in both cell lines which was completely abrogated after pretreatment with the broad spectrum caspase inhibitor zVAD-fmk. NO triggered also a time-dependent activation of caspase-1, caspase-3, and caspase-6 in these cells. Moreover, NO caused a release of mitochondrial protein cytochrome c into the cytosol, an increase in the number of cells with low mitochondrial transmembrane potential and with high level of reactive oxygen species production. However, NO did not induce mRNA expression of CD95 (APO-1/Fas) ligand. FAS-associated phosphatase-1 (FAP-1) molecule was constitutively expressed at the mRNA level and did not show any changes upon NO treatment in both breast cancer cell lines. The expression of the pro-apoptotic protein Bax and of the anti-apoptotic protein Bcl-2 remained unchanged in MCF-7 and BT-20 cells upon GTN treatment. We suggest that the mechanism of NO-mediated activation of the caspase cascade and subsequent apoptosis in human breast cancer cells required mitochondrial damage (in particular, cytochrome c release, disruption of mitochondrial transmembrane potential and generation of reactive oxygen species) but not the activation of the CD95/CD95L pathway.

[Years of life lost by mortality: a component of the burden of disease]

INTRODUCTION

The register of death by cause, sex and age groups of residents in 1994 in Rio Grande do Sul (RS) and Santa Catarina (SC), two Brazilian southern states, were studied to calculate the years of life lost (YLL), one of the two components that summarize disability adjusted life years (DALY), in RS, SC and Brazil.

METHODS

The methodology employed is the same used in the Global Burden of Disease study to quantify the mortality component (YLL) of DALY in the world.

RESULTS

The results show that the greatest proportion and rates caused by Group II (Noncommunicable diseases), linked with more advanced stages of the epidemiological transition, in RS, SC and Brazil. But in both states and especially in Brazil, Group I (Communicable, maternal, perinatal and nutritional conditions) causes an important proportion of YLL. The Group III (Injuries) was the second more important group in RS and SC and the third in Brazil. Road traffic accidents are particularly important in SC, where the intentional injury rate is half than the one in RS. The leading causes of YLL were road traffic accidents, ischemic heart disease and cerebrovascular disease in SC, and ischemic heart disease, cerebrovascular disease and road traffic accidents in RS.

CONCLUSIONS

Death certification in the southern region of Brazil has a complete coverage and miscoded death proportion is small, providing a reliable mortality information. DALY allow comparing fatal and nonfatal health outcomes to determine the importance of different diseases and to establish health priorities. DALY are also an useful tool to identify disadvantaged groups, target health interventions and provide information for social control of resource allocation.

Genetic structure of natural populations of Escherichia coli in wild hosts on different continents

Current knowledge of genotypic and phenotypic diversity in the species Escherichia coli is based almost entirely on strains recovered from humans or zoo animals. In this study, we analyzed a collection of 202 strains obtained from 81 mammalian species representing 39 families and 14 orders in Australia and the Americas, as well as several reference strains; we also included a strain from a reptile and 10 from different families of birds collected in Mexico. The strains were characterized genotypically by multilocus enzyme electrophoresis (MLEE) and phenotypically by patterns of sugar utilization, antibiotic resistance, and plasmid profile. MLEE analysis yielded an estimated genetic diversity (H) of 0.682 for 11 loci. The observed genetic diversity in this sample is the greatest yet reported for E. coli. However, this genetic diversity is not randomly distributed; geographic effects and host taxonomic group accounted for most of the genetic differentiation. The genetic relationship among the strains showed that they are more associated by origin and host order than is expected by chance. In a dendrogram, the ancestral cluster includes primarily strains from Australia and ECOR strains from groups B and C. The most differentiated E. coli in our analysis are strains from Mexican carnivores and strains from humans, including those in the ECOR group A. The kinds and numbers of sugars utilized by the strains varied by host taxonomic group and country of origin. Strains isolated from bats were found to exploit the greatest range of sugars, while those from primates utilized the fewest. Toxins are more frequent in strains from rodents from both continents than in any other taxonomic group. Strains from Mexican wild mammals were, on average, as resistant to antibiotics as strains from humans in cities. On average, the Australian strains presented a lower antibiotic resistance than the Mexican strains. However, strains recovered from hosts in cities carried significantly more plasmids than did strains isolated from wild mammals. Previous studies have shown that natural populations of E. coli harbor an extensive genetic diversity that is organized in a limited number of clones. However, knowledge of this worldwide bacterium has been limited. Here, we suggest that the strains from a wide range of wild hosts from different regions of the world are organized in an ecotypic structure where adaptation to the host plays an important role in the population structure.

Sialoadhesin-positive host macrophages play an essential role in graft-versus-leukemia reactivity in mice

We recently established an effective immune T-cell-mediated graft-versus-leukemia (GVL) murine model system in which complete tumor remissions were achievable even in advanced metastasized cancer. We now describe that this T-cell-mediated therapy is dependent on host macrophages expressing the lymphocyte adhesion molecule sialoadhesin (Sn). Depletion of Kupffer cells in tumor-bearing mice during adoptive immunotherapy (ADI) or the treatment of these animals with anti-Sn monoclonal antibodies led to complete or partial inhibition of the immune T-cell-mediated therapeutic effect. Furthermore, Sn+ host macrophages in livers formed clusters during ADI with donor CD8 T cells. To test for a possible antigen presentation function of these macrophages, we used as an in vitro model the antigen beta-galactosidase for which a dominant major histocompatibility complex (MHC) class I Ld-restricted peptide epitope is known to be recognized by specific CD8 cytotoxic T lymphocytes (CTL). We demonstrate that purified Sn+ macrophages can process exogenous beta-galactosidase and stimulate MHC class I peptide-restricted CTL responses. Thus, Sn+ macrophages, which are significantly increased in the liver after ADI, may process tumor-derived proteins via the MHC class I pathway as well as via the MHC class II pathway, as shown previously, and present respective peptide epitopes to CD8 as well as to CD4 immune T cells, respectively. The synergistic interactions observed before between immune CD4 and CD8 T cells during ADI could thus occur in the observed clusters with Sn+ host macrophages.

Activation of NMDA receptors protects against glutamate neurotoxicity in the retina: evidence for the involvement of neurotrophins

Activation of glutamate receptors has been implicated in excitotoxicity. Here, we have investigated whether subtoxic concentrations of glutamate can modulate neuronal death in the developing retina. Explants of rat retinas were pre-incubated with glutamate, N-methyl-d-aspartate (NMDA), kainate, quisqualate or trans-1-amino-1,3-cyclopentanedicarboxylic acid (t-ACPD) for 18 h. Then, glutamate (6 mM) was added to the explants for an additional 6 h. Glutamate-induced degeneration was restricted to the emerging inner nuclear layer. Pre-incubation with glutamate, NMDA, or both, reduced glutamate-induced neuronal death and protected against neuronal death induced by irradiation (2 Gy). The NMDA receptor antagonists, 2-amino-5-phosphonovaleric acid (d-APV; 30 microM) or 5-methyl-10,11-dihydro-5H-dibenzocyclohepten-5,10-imine hydrogen maleate (MK-801; 30 microM), prevented glutamate-induced neuroprotection. To investigate whether this neuroprotection was mediated by neurotrophins, we incubated retinal explants with either brain-derived neurotrophic factor or neurotrophin-4. Both treatments resulted in partial protection against glutamate-induced neurotoxicity. Furthermore, NMDA mediated neuroprotection was totally reversed when a soluble form of the specific tyrosine kinase receptor B was simultaneously added to the explants. Our results suggest that activation of NMDA receptors may control neuronal death in the retina during development. This modulation seems to depend, at least in part, on the release of neurotrophins within the retina.

Graft-versus-leukemia reactivity involves cluster formation between superantigen-reactive donor T lymphocytes and host macrophages

T-cell-mediated antitumor effects play an important role clinically in allogeneic graft-versus-leukemia (GvL) reactivity, whereas T-cell-mediated antihost effects are associated with a risk of developing graft-versus-host (GvH) disease. GvL and GvH were compared in an animal tumor model system after the systemic transfer of allogeneic antitumor immune T lymphocytes from B10.D2 [H-2d; minor lymphocyte-stimulating antigen (Mls)b] mice into ESb-MP tumor-bearing or normal DBA/2 (H-2d; Mls(a)) mice. Here we demonstrate that this T-cell-mediated therapy involves the formation of clusters of donor CD4 and CD8 T cells with host macrophages, in particular, with a subpopulation expressing the lymphocyte adhesion molecule sialoadhesin. DBA/2 mice and the derived tumor ESb-MP express viral superantigen 7 (Mls(a)), an endogenous viral superantigen that is absent from B10.D2 mice. To test the contribution of viral superantigen 7-reactive Vbeta6 donor T cells in the GvL-mediated eradication of liver metastases, we performed immunohistological and transmission electron microscopy studies. Vbeta6+ CD4 and CD8 T cells from B10.D2 donors formed tight clusters with host sialoadhesin-positive macrophages, and transmission electron microscopy pictures revealed direct membrane-membrane interactions between T cells and macrophages. Clusters were more abundant and consisted of more cells in tumor-bearing hosts (GvL model) than in non-tumor-bearing hosts (GvH model). In addition, Vbeta6 T cells within the clusters showed a strong proliferation activity, indicating stimulation. Moreover, in an in vitro tumor cytostasis assay, primed as well as nonprimed purified Vbeta6 T cells from donor mice were able to inhibit the proliferation of superantigen-expressing ESb-MP lymphoma cells. This suggests that the transferred superantigen-reactive Vbeta6 T cells contribute to the eradication of metastases. The observed cell clusters might be sites for antigen presentation and the activation of tumor-reactive T cells.

Identification of four genes in endothelial cells whose expression is affected by tumor cells and host immune status--a study in ex vivo-isolated endothelial cells

A spontaneously metastasizing, well-defined mouse lymphoma was chosen as an in vivo model to study the effect of tumor-host interaction on gene expression in liver sinusoidal endothelial cells. Forty-nine bovine aortic endothelial cell (BAEC) genes, recently isolated by a differential screening approach of a cDNA library enriched for tumor necrosis factor-alpha (TNF-alpha) suppressed genes, were investigated. Four of these genes were finally selected because they were affected differentially by host immuno-competence, TNF-alpha, and tumor cells. Sequence analysis showed them to encode the bovine polyubiquitin (A4), elongation factor 1alpha (B2), the acidic ribosomal phosphoprotein PO (C3), and the ribosomal protein S2 (E10). Gene expression was analyzed by dot-blot or Northern blot analysis. TNF-alpha and tumor cell conditioned supernatant suppressed the genes additive in BAEC but not in other endothelial cells except for bovine capillary endothelial cells. Ex vivo-isolated liver endothelial cells of tumor-bearing syngeneic DBA/2 mice showed strong downregulation of these four genes in comparison to normal control values. In contrast, endothelial cells of tumor-bearing immuno-incompetent Balb/c (nu/nu) mice showed no downregulation but upregulation of these genes. Consistently, all four genes were also downregulated when BAEC were incubated with supernatants derived from ex vivo-isolated liver metastases from immuno-competent but not from -incompetent mice. Thus, the expression of a group of genes involved in protein translation and processing was more profoundly altered in endothelial cells in vivo than in vitro, suggesting that microenviromental factors and cell-cell and cell-matrix interactions play an important role.

Changes in cytochrome oxidase activity in brown adipose tissue during oestrous cycle in the rat

Cold-acclimated female Wistar rats were killed at a known phase of the oestrous cycle to investigate whether natural fluctuations of female sex steroids during the cycle are mirrored by changes in brown adipose tissue (BAT) activity. Four phases: proestrus, oestrus, dioestrus I and dioestrus II, were identified by the cells types appearing in vaginal smears. BAT was removed and analysed for composition and specific indicators of BAT activity. No changes in BAT mass, protein or mitochondrial content were detected during the cycle. Thermogenesis was also unchanged as judged by both lipid multilocularity and mitochondrial GDP-binding. However, cytochrome c oxidase (COX) activity did cycle with a minimum at proestrus and a maximum at dioestrus I. The involvement of oestradiol in such a cycle is suggested by the fact that oestradiol treatment decreased COX activity to values similar to those found in proestrus. The physiological function of a cyclic oxidative capacity remains to be elucidated.

Effect of fat distribution on the pharmacokinetics of cortisol in obesity

OBJECTIVE

Patients with predominantly upper body obesity are at greater risk for developing diabetes mellitus, hyperlipidemia, hypertension, and cardiovascular disease. Little is known about the mechanisms involved in the regulation of regional body distribution. It has been accepted that the accumulation of fat into adipose tissue depends on regional metabolic regulation of adipocytes and that glucocorticoids play a role in this mechanism. The aim of the present study is to investigate how the pharmacokinetics of cortisol correlate to intraabdominal and subcutaneous fat distribution in obese patients.

METHODS

A group of 24 obese patients (13 males and 11 females) were submitted to a CT scan for intraabdominal and subcutaneous fat area evaluation. A 30-min cortisol infusion (0.25 mg/kg) was administered and plasma cortisol was measured over 6 hours.

RESULTS

Patients with larger intraabdominal fat areas were found to have a higher cortisol clearance than those with lower intraabdominal fat areas. Cortisol clearance (both, absolute and body-weight corrected) showed a statistically significant correlation with intraabdominal fat area, either expressed by waist-hip ratio or obtained by computerized tomography.

CONCLUSIONS

These findings indicate a more effective clearance capability for cortisol in patients with central obesity resulting in lowered cortisol plasma levels despite an increased cortisol secretion observed in this patient group.

Loss of endogenous mouse mammary tumor virus superantigen increases tumor resistance

From a cross between a tumor-susceptible mouse strain (DBA/2; D) and a tumor-resistant MHC-identical strain (B10.D2; D2) new recombinant inbred mouse strains were established over many generations of inbreeding and tumor resistance selection. Since resistance to the highly metastatic DBA/2 lymphoma variant ESb had an immunologic basis, and the two parental strains differed in endogenous viral superantigens (vSAGs), DNA of three D2 x D recombinant inbred mouse lines was typed for endogenous mouse mammary tumor viruses using mouse mammary tumor virus long terminal repeat- and env gene-specific probes. The resistant D2 x D mice were very similar to the susceptible parental strain D in their Mtv Southern blots, except for the lack of a single band corresponding to Mtv-7, the provirus coding for the strong DBA/2 superantigen Mls-1a. A backcross analysis revealed that Mtv-7-negative F2 mice were significantly more resistant than Mtv-7-positive F2 mice. When Mtv-7 was reintroduced into the resistant lines by crossing them with either CBA/J or BALB/D2.Mls-1a, the mice became again more tumor susceptible. Finally, we demonstrate the ability to transfer immunoresistance and graft-vs-leukemia reactivity from tumor-resistant to tumor-susceptible mice.

Caspase activation is required for nitric oxide-mediated, CD95(APO-1/Fas)-dependent and independent apoptosis in human neoplastic lymphoid cells

Nitric oxide (NO), an important effector molecule involved in immune regulation and host defense, was shown to induce apoptosis in lymphoma cells. In the present report the NO donor glycerol trinitrate was found to induce apoptosis in Jurkat cells that are sensitive to CD95-mediated kill. In contrast, a CD95-resistant Jurkat subclone showed substantial protection from apoptosis after exposure to NO. NO induced mRNA expression of CD95 (APO-1/Fas) and TRAIL/APO-2 ligands. Moreover, NO triggered apoptosis in freshly isolated human leukemic lymphocytes which were also sensitive to anti-CD95 treatment. The ability of NO to induce apoptosis was completely blocked by a broad-spectrum ICE (interleukin-1beta converting enzyme)-protease/caspase inhibitor and correlated with FLICE/caspase-8 activation. This activation was abrogated in some neoplastic lymphoid cells but not in others by the inhibitor of protein synthesis cycloheximide. Our results were confirmed using an in vitro experimental model of coculture of human lymphoid target cells with activated bovine endothelial cells generating NO as effectors. Furthermore, the inhibition of endogenous NO production with the inducible NO synthase inhibitor NG-monomethyl-L-arginine caused a complete abrogation of the apoptotic effect. Our data provide evidence that NO-induced apoptosis in human neoplastic lymphoid cells strictly requires activation of caspases, in particular FLICE, the most CD95 receptor-proximal caspase. Depending on the cell line tested this activation required or was independent of the CD95 receptor/ligand system.