Effects of various modes of androgen substitution therapy on erythropoiesis

In order to investigate differential effects of androgens on erythropoiesis, 55 men with clincally and biochemical confirmed hypogonadism were randomly assigned to 4 groups receiving different forms of androgen substitution: Mesterolone (MES) 100 mg/d, testosterone undecanoate (TU) 160 mg/d, testosterone enanthate (TE) 250 mg i.m./21 days or 1200 mg crystalline testosterone (TPEL) subcutaneously implanted at study begin. Previous testosterone medication had been suspended at least 3 months prior to study begin. Testosterone (T), dihydrotestosterone (DHT), hemoglobin (HB) and hematocrit (HC) were assessed before, during and after substitution of androgens. MES did not increase serum T and TU raised average T levels during substitution to 5.7 +/- 0.3 nmol/l, thereby doubling baseline concentrations. TE resulted in a 6fold increase of baseline T yielding 13.5 +/- 0.7 nmol/l and TPEL increased serum T 8.5fold to 23.2 +/- 1.1 nmol/l. Average DHT levels during substitution were 4.3 +/- 0.2 (MES), 3.3 +/- 0.2 (TU), 4.0 +/- 0.4 (TE) and 5.5 +/- 0.4 (TPEL) nmol/l. The groups receiving TPEL, TU or TE showed a significant rise of HB and HC compared to baseline, whereas in the MES group these parameters did not change significantly. MES increased HB by 5.6 +/- 1.8 g/l, TU by 12.7 +/- 2.8 g/l, TE by 21.1 +/- 2.6 g/l and TPEL by 21.7 +/- 4.0 g/l. HC was raised by 1.8 +/- 0. 4% in the MES group, 3.9 +/- 1.1% in the TU group and 6.4 +/- 0.9% and 6.5 +/- 1.6% in the TE and TPEL groups, respectively. Except for 1 subject in the TPEL group, the HB and HC stayed within the normal limits. We conclude that, T, but not DHT, stimulates erythropoiesis in a dose dependent manner. T levels within the low normal range for men are required for maximal stimulation of erythropoiesis.

Pharmacokinetics and pharmacodynamics of subcutaneous testosterone implants in hypogonadal men

OBJECTIVE

There are advantages and disadvantages with all of the presently available types of testosterone replacement for hypogonadal men. We performed this investigation to establish detailed data about the pharmacokinetics, pharmacodynamics, feasibility and side-effects of subcutaneously implanted testosterone (T) pellets.

DESIGN AND MEASUREMENT

In a single-dose, open-label, non-randomized study, 6 T-pellets, each containing 200 mg of fused crystalline T, were implanted in the subdermal fat tissue of the lower abdominal wall of 14 hypogonadal men. Blood samples for determination of T, LH, FSH, 5 alpha-dihydrotestosterone (DHT), sex hormone binding globulin (SHBG) and oestradiol (E2) were obtained at 0, 0.5, 1, 2, 4, 8, 12, 24, 36, 48 hours and on day 21 after implantation and then every 3 weeks until day 189, and on days 246 and 300 during follow-up. In another 36 hypogonadal men the feasibility and side-effects of T-pellets were evaluated.

PATIENTS

Fourteen patients participated in the detailed pharmacokinetic study and another 36 patients in the assessment of feasibility and side-effects. All patients (age range 18-61 years) suffered from primary or secondary hypogonadism (T < 3.6 nmol/l).

RESULTS

The pharmacokinetic study in 14 hypogonadal men revealed an initial short-lived burst release of T with a peak concentration of 49.0 +/- 3.7 nmol/l at 0.5 +/- 0.13 days which was followed by a stable plateau lasting until day 63 (day 2, 35.2 +/- 2.3; day 63, 34.8 +/- 2.6 nmol/l). Thereafter serum T gradually declined and was close to baseline concentrations on day 300. Apparent terminal elimination half-life (t1/2) was 70.8 +/- 10.7 days and apparent mean residence time 87.0 +/- 4.5 days. On average, serum T was below 10 nmol/l after 180 days. Absorption of T followed a zero-order release kinetic with an absorption half-time of 74.7 days (95% confidence interval: 71.1-78.5) and was almost complete by day 189 (95.9 +/- 0.84%). Serum DHT and E2 were significantly elevated from day 21 to day 105 and correlated significantly with T (DHT, r = 0.65, P < 0.0001, E2, r = 0.67, P < 0.0001). SHBG was significantly decreased from day 21 to day 168. In 6 men with primary hypogonadism T suppressed LH and FSH to the eugonadal range from day 21 to 126 and 42 to 105, respectively, with nadirs occurring at day 84 (LH) and day 63 (FSH). LH and FSH were highly inversely correlated with T (r = -0.47 and -0.57). The only side-effect observed during 112 implantations in the total group of 50 men were 6 local infections (5.4%) leading to extrusion of 5 pellets in 3 men. When given the choice, all patients except one preferred T-pellets to their previous T medication for permanent substitution therapy.

CONCLUSION

T-pellets are the androgen formulation with the longest biological action and strongest pharmacodynamic efficacy in terms of gonadotrophin suppression. The pharmacokinetic features are advantageous compared to other T preparations and the patient acceptance is high.

Somatic recombination, gene amplification and cancer

The principle objective of this research programme, to analyse chemical induction of somatic recombination and related endpoints, i.e., mobilization of transposing elements and gene amplification, has been approached by means of several assay systems. These have included Drosophila, Saccharomyces and mammalian cell cultures. 6.1. Screening assays for mitotic recombination. A large number of chemicals have been investigated in the three Drosophila assay systems employed--the multiple wing hair/flare wing spot system developed by Graf et al., 1984, the white-ivory system developed by Green et al., 1986 and the white/white+ eye spot assay developed by Vogel (Vogel and Nivard, 1993). Particularly the screening of 181 chemicals, covering a wide array of chemical classes, by the last mentioned assay has shown that measurement of somatic recombination in Drosophila constitutes a sensitive and efficient short-term test which shows a remarkably good correlation with the agent score of 83 short-term tests analysed by ICPEMC (Mendelsohn et al., 1992; Table 2) as well as the assay performance in international collaborative programmes measuring carcinogen/non-carcinogens (de Serres and Ashby, 1981; Ashby et al., 1985, 1988). Also the wing spot assay has gained wide international recognition as a similarly sensitive test. These two assay systems in Drosophila measure both intrachromosomal events and interchromosomal recombination. The white-ivory system on the other hand is based on the loss of a tandem duplication in the white locus, the mechanism of which is less known, but probably involves intrachromosomal recombination. The difference in the mechanism between this assay and the former two was indicated by the lack of response to methotrexate in the white-ivory assay, while this compound was strongly recombinogenic in both the wing spot and white/white+ assays. The use of different strains of Drosophila with the white/white+ assay demonstrated the importance of the background genotype for the outcome of the test. Up to a 60-fold variation was found between the different genotypes in the response to procarcinogens, evidently dependent on differences in the metabolic activation of procarcinogens. In 1989 Schiestl presented results on intrachromosomal recombination in the strain RS112 of Saccharomyces, which indicated a capability to detect a range of chemical carcinogens, which gave negative results in Ames Salmonella assay. Such a test system, which could identify a larger range of potential carcinogens than conventional short-term tests evidently would be of great value and it therefore seemed of importance to follow up the observations by Schiestl. However, studies within this programme on the same strain of Saccharomyces, as well as the strains D7 (measuring intragenic recombination, intergenic recombination, and point mutation) and JD1 (measuring intragenic recombination at two loci) could not support the observations and interpretation by Schiestl (1989). The Drosophila white-ivory system, which presumably responds primarily by intrachromosomal recombination, did not give positive results with these Salmonella-negative agents either. One system to measure mitotic recombination in mammalian cell cultures was developed in the present programme. It was based on heterozygous mutations in both alleles of the adenosine deaminase gene (ADA). The system selects for proficient recombinants generated by the deficient cells. So far only pilot experiments, indicating that this experimental system operates as planned, have been performed. 6.2 Mechanisms of mitotic recombination The induction of mosaic spots in the wing spot and the white/white+ assays is predominantly dependent on interchromosomal recombination. This is evident from the fact that heterozygous inversions reduce the frequency of spots. A relationship between the length of inversions and the reduction of spots was demonstrated in the white/white+ assay--the long inversion ln(l)sc4L

[A review of epidemiologic studies on ultrasound during pregnancy]

This article reviews most of the more recent epidemiological studies on the effectiveness and possible risks of conventional sonography. With the help of such a review, case reports, very often cited out of context, can be better evaluated. Publications which have attempted to study the number of malformations, diagnosable by ultrasound, and to the effect of ultrasound on postnatal mortality and morbidity are scrutinized. Furthermore the question of possible late effects of ultrasound is addressed, such as effects on birth weight, neural development and cancer incidence. Routine sonography is of great value; no negative late effects on the child have been found. The effectiveness and risks of Doppler flow ultrasound have not been studied sufficiently well to allow a similar conclusion.

The neurosteroid pregnenolone sulfate blocks deficits induced by a competitive NMDA antagonist in active avoidance and lever-press learning tasks in mice

The neurosteroid pregnenolone sulfate (PREG-S) has been shown to modulate positively NMDA receptor activity and to have memory enhancing properties in mice. The present study was designed to evaluate the effects of post-training administration of PREG-S, alone or in combination with D-2-amino-5-phosphonovalerate (D-AP5), a competitive NMDA receptor antagonist, in Y-maze avoidance and appetitively motivated lever-press learning tasks and in a traction reflex test in mice. Intracerebroventricular (i.c.v.) administration of PREG-S (0.01-0.1 nmol/mouse) blocked the selective retention deficits induced by 0.02 nmol D-AP5 in the Y-maze avoidance task. PREG-S (0.1 nmol, i.c.v.) also blocked the retention deficits induced by 0.02 nmol D-AP5 in the lever-press task. Post-training administration of PREG-S alone (0.001-0.1 nmol, i.c.v.) had no effect on retention performance in the Y-maze and the lever-press tasks. PREG-S (1-10 nmol, i.c.v.) significantly reduced the impairment of the traction reflex induced by 2 nmol D-AP5. The ability of PREG-S to block retention performance deficits as well as motor impairment induced by D-AP5 is in agreement with its positive modulatory action at NMDA receptors.

1,3-Butadiene working group report

During the Workshop in North Carolina, the in vivo metabolism, adduct formation and genotoxicity data available from rodent and human exposure to 1,3-butadiente (BD) were reviewed and they are summarized in the present report. BD is metabolized by cytochrome P-450-dependent monoxygenases to the primary metabolite 1,2-epoxybutene-3 (epoxybutene, EB). EB is subjected to further metabolism: oxidation to 1,2:3,4-diepoxybutane (DEB), hydrolysis to 3-butene-1,2-diol and conjugation to glutathione. The first pathway seems to prevail in mice while the latter is characteristic for rats and possibly for humans. Species differences exist in adduct formation of the monoepoxide to hemoglobin, for which the following pattern has been found: mice > rats > humans. Genotoxity of BD was found in mice with all applied tests; however, negative results were obtained in rats. In exposed humans, the cytogenetic studies in peripheral blood lymphocytes did not show genotoxic effects, although one report described elevated hprt variant levels in peripheral blood lymphocytes of exposed workers. It was concluded that the presently available data are insufficient for the application of the parallelogram model to estimate genetic risk for humans. As an alternative approach, a tentative estimate of the doubling dose for induction of hprt mutations in somatic cells of mice and men was performed and the calculated values were surprisingly similar, i.e. 9000 ppmh. However, this estimate is burdened with a number of caveats which were discussed in detail. The working group identified a series of urgent research needs to provide the appropriate data for the application of the parallelogram model, such as identification of metabolic pathways in different rodent species and humans, metabolic studies in mice, rats and humans considering metabolic polymorphisms, studies of adducts to DNA and hemoglobin especially of DEB and other butadiene metabolites in rodents and humans, studies of mutational spectra (mutational fingerprinting) in somatic and germinal cells, confirmation of the human hprt mutation data, conformation of the rodent malformation data, dose-response studies in rodent germ cell tests and studies on repair kinetics of mono-adducts induced by EB as opposed to repair of cross-links produced by DEB. Finally, it was suggested that the original parallelogram consisting of data from somatic cell studies in rodents and humans plus studies of heritable effects in rodents to extrapolate to germ cell risk for humans should be supplemented with studies in sperm of experimental animals and exposed men.

A defect in the early phase of T-cell receptor-mediated T-cell activation in patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) is characterized by an impairment of specific antibody production and a decrease in all or selected Ig isotypes. Abnormalities at the level of the B cells, T cells, and antigen-presenting cells have been described. In the present study, we have focused our attention on T-cell activation in CVID. T cells from 15 of 24 patients failed to respond to recall antigens (eg, tetanus toxoid, Escherichia coli). Of these 15 patients, 11 were studied in detail and showed significantly decreased T-cell proliferative responses and/or decreased interleukin-2 and interferon-gamma production on T-cell receptor-mediated stimulation with recall antigens and superantigens (staphylococcal enterotoxins [SE]); however, T-cell response to mitogens (anti-CD3 monoclonal antibody, phytohemagglutinin) was normal. The defect in interleukin-2 and interferon-gamma release on tetanus toxoid stimulation could also be documented in purified CD4 T cells of the patients and was present in patients with high and normal CD8 counts alike. Furthermore, patients' T cells failed to mount a significant elevation in free intracellular calcium (Ca++ flux) in response to superantigen, whereas the response to phorbol myristate acetate and ionomycin, bypassing receptor-mediated signaling, was unimpaired. These results indicate a defect in the early phase of T-cell activation after triggering of the T-cell receptor in a significant subgroup of CVID patients.

Mechanism-based predictions of interactions

Exposure to more than one toxic compound is common in real life. The resulting toxic effects are often more than the simple sum of the effects of the individual compounds. It is unlikely that it will ever be possible to test all combinations. It is therefore highly desirable to improve or develop means for reasonably approximating predictions of interactions. In order to be valid and extrapolatable, these predictions are most promising if they are mechanism-based. Examples will be given for possibilities of mechanism-based predictions of interactions which exceed trivialities of simple increases by enzyme induction of enzymatic rates of a given biotransformation pathway leading to a toxic metabolite. Instead, examples will be provided where competition between various enzymes for shunting the same substrate into divergent pathways can lead to predictable dramatic changes in toxicity by shifting the metabolic routes under conditions of no significant changes of overall metabolism. Further examples are given on predictable interactions between chemicals which need bioactivation for exerting their toxicity and chemicals which effect hormonal status and other endogenous factors which in turn modify enzymes involved in the control of toxic metabolites.

Impaired TCR signal transduction, but normal antigen presentation, in a patient with common variable immunodeficiency

We describe a 27-year-old white man with common variable immunodeficiency (CVID) who has two healthy histoidentical brothers and one IgA-deficient sister who shares one HLA haplotype with the patient. T cells from the patient with CVID showed an impaired response to recall antigens (tetanus toxoid, E. coli), whereas his IgA-deficient sister and his two healthy histoidentical brothers responded normally. Cross-mixing experiments using isolated monocytes and T cells from the CVID patient and one histoidentical brother revealed that the patient's monocytes were fully functional in processing and presenting antigen to resting T cells of his brother, and provided normal accessory cell function for superantigen-induced activation of his brother's resting T cells. In contrast, the patient's T cells were unable to respond to antigen presented by the brother's monocytes and failed to respond with an increase in intracellular free Ca++ to stimulation with superantigen, which is known to bind to the TCR V beta-chain outside the antigen-binding groove. However, stimulation with a combination of PMA and IM, directly activating protein kinase C and increasing intracellular free Ca++ by bypassing membrane receptors, induced normal Ca++ flux. These data indicate that the patient with CVID has a defect in TCR-mediated signalling at the level of the T cells which is not present in his histoidentical healthy brothers or in his haploidentical IgA-deficient sister.

Inhibition of receptor-dependent and receptor-independent generation of the respiratory burst in human neutrophils and monocytes by human serum IgA

An important feature of the role of IgA in protection against infection and disease at the level of the mucosal surfaces might be the elimination of pathogens without induction of a strong inflammatory reaction. In the present study we addressed the question whether IgA has a regulatory effect on the generation of reactive oxygen intermediates in human neutrophils and monocytes (i.e. the respiratory burst). Cells were stimulated with heat-inactivated Haemophilus influenzae type b or phorbol myristate acetate, stimuli known to use different recognition structures or signal transduction pathways. Concentrations of IgA as low as 10 mg/L significantly inhibited the receptor-dependent Haemophilus influenzae-induced respiratory burst in granulocytes, as assessed by measuring luminol-enhanced chemiluminescence. Furthermore, IgA had a dose-dependent inhibitory effect on the receptor-independent induction of the respiratory burst, as examined by flow cytometry in monocytes and granulocytes activated with phorbol myristate acetate. Our results therefore indicate that inhibition of receptor-ligand interaction is not a sufficient explanation for the IgA-mediated modulation of the respiratory burst in human phagocytic cells. In addition, IgA might directly regulate the activation of the respiratory burst at the level or downstream of protein kinase C activation. By modulating the release of mediators of inflammation such as reactive oxygen intermediates, the inflammatory response could be down-regulated at the level of the mucosal surfaces, thereby preventing the development of sequelae of an exaggerated inflammatory response potentially leading to local or systemic pathology.

Human serum IgA downregulates the release of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6) in human monocytes

While the protective effect of IgA antibodies against infection of the mucosal surfaces is well documented, the mechanisms involved are not entirely clear. The aim of the current study is to investigate the effect of human serum IgA on the release of inflammatory cytokines in human monocytes activated with a particulate stimulus, Haemophilus influenzae type b (Hib), or soluble lipopolysaccharide (LPS) purified from Escherichia coli. Our results show that IgA downregulates tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) production, whereas IgG examined in parallel had no effect. IgA had no inhibitory effect on Hib-induced granulocyte-macrophage colony-stimulating factor release. TNF-alpha and IL-6 release were downmodulated if IgA was present during cytokine induction, and IgA was also inhibitory if added to Hib-pretreated monocytes during the phase of cytokine release. These findings indicate that there are at least two mechanisms whereby IgA antibodies can downregulate TNF-alpha and IL-6 release in human monocytes: by a mechanism acting during the time of monocyte activation, and a mechanism that downregulates the production and/or the release of these cytokines in activated monocytes. Regulation of TNF-alpha and IL-6 release by IgA may be among the antiinflammatory mechanisms preventing an uncontrolled release of potentially noxious levels of inflammatory cytokines during acute and/or chronic inflammation.

The costimulatory signal CD28 is fully functional but cannot correct the impaired antigen response in T cells of patients with common variable immunodeficiency

A wide spectrum of different immunologic abnormalities have been postulated as being responsible for the impairment of specific antibody production and the decrease in all or selected immunoglobulin isotypes present in common variable immunodeficiency (CVID). These abnormalities include impaired B cell differentiation and/or function, defective macrophage function, and significant T cell defects. The aim of the present study was to delineate whether the accessory molecule CD28 is involved in the impaired antigen response of T cells from patients with CVID. Our results demonstrate that CD28 costimulation was functional in T cells stimulated with anti-CD3 or anti-TCR MoAb, but could not correct the impaired response of patients' peripheral blood T cells to tetanus toxoid. Analysis of patients' long-term cultured T cells further confirmed these results. Exogenous rIL-2, another costimulus, augmented but did not correct the defective proliferation and lymphokine production in patients' antigen-driven peripheral blood T lymphocytes or in long-term cultured T cells. These findings indicate that the CD28 signalling pathway in these patients' T cells is unimpaired, and that costimulation via CD28 cannot correct the defect occurring in the course of TCR-mediated T cell activation.

Infection of human polyomaviruses JC and BK in peripheral blood leukocytes from immunocompetent individuals

Widely disseminated infection with the human polyomaviruses JC and BK is followed by lifelong asymptomatic viral persistence that can be reactivated under prolonged immunosuppression to fatal CNS and urogenital disease. In an attempt to understand the pathogenesis of polyomavirus diseases, we asked whether leukocytes are involved in polyomavirus infection in the immunocompetent host. Peripheral blood leukocytes from 29 immunocompetent individuals and umbilical cord blood from 10 newborn children were analyzed for the presence of polyomavirus DNA. Southern blot analysis demonstrated the presence of JCV-specific full-length virus genomes and indicated involvement of the second human polyomavirus BK. In contrast to specimens from newborn children, PCR amplification of target DNA in the adult age group followed by species-specific hybridization provided evidence of concomitant JCV and BKV infection in almost all specimens. Nucleotide sequencing of virus-specific products representing DNA segments essential for virus multiplication confirmed presence of both virus species in leukocytes. The detection of a new virus subtype and single base changes or deletions in the noncoding DNA region from individual cases suggested widespread heterogeneity in the circulating virus population, although the structure of the transcriptional control elements in all cases was comparable to highly active elements found in lytically infected cells. Those findings and the localization of both virus types in the nuclei of blood cells by in situ hybridization demonstrate that JCV and BKV frequently infect peripheral leukocytes and give strong evidence that leukocytes are common sites of polyomavirus persistence in healthy individuals.

The free-exploratory paradigm: an effective method for measuring neophobic behaviour in mice and testing potential neophobia-reducing drugs

When given the opportunity to choose between a novel and a familiar compartment (free-exploratory paradigm), BALB/c mice exhibited a preference for familiar places and a marked number of attempts at entry into the novel compartment followed by avoidance responses. In contrast, C57BL/6 mice showed a preference for novel places and very few avoidance responses towards novelty. When novelty was reduced by two familiar odours, fresh sawdust or urine of conspecifics, the neophobia of the BALB/c mice was reversed and the animals clearly showed a preference for the novel compartment. This experimental paradigm can be proposed as an effective animal model for investigating drugs potentially able to reduce neophobia in BALB/c mice. The effects of anxiolytics, effective in the usual animal models of "state" anxiety, were investigated in the free-exploratory paradigm which may model another type of anxiety, termed by Lister (1990) "trait" anxiety. Thus, the behavioural effects of two benzodiazepine full agonists, chlordiazepoxide and diazepam, two non-benzodiazepine partial agonists at benzodiazepine receptors, Ro 19-8022 and alpidem, the 5-HT(1A) receptor agonist, 8-OH-DPAT, and the 5-HT(3) receptor antagonist, zacopride, were assessed in BALB/c and C57BL/6 mice. Chlordiazepoxide, diazepam and Ro 19-8022 completely reversed the preference of BALB/c mice for the familiar compartment, treated animals exhibiting a significant preference for novel places. In contrast, alpidem, 8-OH-DPAT and zacopride did not significantly modify their behaviour. Moreover, the same drugs did not modify the specific responses of C57BL/6 mice toward novelty. These results demonstrate that drugs which bind in a non-selective manner to heterogeneous benzodiazepine recognition sites were very effective in reducing neophobia in BALB/c mice, whereas 5-HT-interacting drugs were unable to counteract their neophobic behaviour. Thus, the free-exploratory paradigm can be proposed as an effective method for testing potential neophobia-("trait" anxiety) reducing drugs.

Tumour localisation kinetics of photofrin and three synthetic porphyrinoids in an amelanotic melanoma of the hamster

In this study the localisation of porphyrinoid photosensitizers in tumours was investigated. To determine if tumour selectivity results from a preferential uptake or prolonged retention of photosensitizers, intravital fluorescence microscopy and chemical extraction were used. Amelanotic melanoma (A-Mel-3) were implanted in a skin fold chamber in Syrian Golden hamsters. Distribution of the porphyrin mixture Photofrin and three porphycenes, pure porphyrinoid model compounds, was studied quantitatively by intravital fluorescence microscopy. Extraction of tissue and blood samples was performed to verify and supplement intravital microscopic results. Photofrin accumulated in melanomas reaching a maximum tumour:skin tissue ratio of 1.7:1. Localisation of the different porphycenes was found to be highly tumour selective (3.2:1), anti-tumour selective (0.2:1), and non-selective (1:1) with increasing polarity of the porphycenes. The two non-tumour selective porphycenes had distinctly accelerated serum and tissue kinetics; serum halflife times being as short as 1 min. The specific localisation of the slowly distributed, tumour selective photosensitizers, occurred exclusively during the distribution from serum and uptake into tissues. For the most selective porphycene, the tumour selection process had a halflife of 260 +/- 150 min and led to a strongly fluorescent tumour edge edema. Accumulation of porphyrines by the amelanotic melanoma (A-Mel-3) can be attributed to an enhanced uptake rate for lipophilic molecules in this subcutaneously growing neoplasm. The slow distribution of the two tumour specific photosensitizers and the strong fluorescence of these hydrophobic molecules in the tumour compartment with a high water content indicate a carrier role of serum proteins in the selection process. Enhanced permeability of the tumour vasculature to macromolecules appears to be the most probable reason for the tumour selectivity of these two sensitisers.

Defective interleukin-2 and interferon-gamma gene expression in response to antigen in a subgroup of patients with common variable immunodeficiency

Patients with common variable immunodeficiency (CVID) are heterogeneous in the clinical manifestations of the disease and in the underlying mechanisms leading to the immunodeficiency. The impairment of B-cell function can be due to an intrinsic defect of the B cells, a deficiency in the function of the antigen-presenting cell, or a dysfunction in the course of T-cell activation. In the present report we have focused our attention on T-lymphocyte activation in three patients with CVID. Numbers of T and B cells, as well as CD4 and CD8 T cell subsets, were within the normal range. The patients' B cells secreted IgM but did not secrete IgG and IgA in response to B-cell stimuli in vitro. Addition of allogeneic T cells was followed by an increase in IgM production but had no effect on the other immunoglobulin isotypes. Examination of T-cell function revealed impaired proliferative response, interleukin-2 (IL-2) and interferon-gamma gene expression and IL-2 release after antigenic stimulation, whereas T-cell proliferation, as well as IL-2 gene expression and release in response to stimulation via anti-CD3, were comparable to those of healthy control subjects. Anti-CD3-induced IFN-gamma gene activation in T cells from two patients was comparable to that of control subjects, whereas T cells from the third patient showed reduced expression of IFN-gamma mRNA. In contrast to the decreased IL-2 and IFN-gamma mRNA levels, IL-2R transcripts examined in parallel were normal in CVID T cells on stimulation with antigen. The defect in IL-2 and IFN-gamma mRNA expression after stimulation with antigen, but not with anti-CD3, suggests an abnormality confined to T-cell activation by the T-cell receptor.

Asbestos-related radiographic abnormalities in elevator construction workers

Elevator construction workers are exposed to asbestos dust during construction and refurbishment work on older buildings. We screened a cohort of workers, all with greater than 20 yr of employment in the industry, with clinical examinations, chest radiography ("B" reader interpretations), and routine spirometry. Twenty of the 91 workers (22%) had evidence of pleural disease, but none of them had an interstitial process consistent with asbestosis. Of those with pleural thickening, 15 had bilateral circumscribed plaques and five had unilateral plaque formation. There were no cases of diffuse pleural thickening, benign pleural effusions, or mesothelioma identified in our cohort. The difference in the mean body mass index of those with pleural abnormalities (29.18 +/- 3.95) and those without (27.7 +/- 3.86) was not statistically significant (p = 0.135). We conclude that elevator construction workers have an increased risk for the development of asbestos-related pleural disease.

[An unusual case of "ocular tumor"]

It is presented a case of symptomatic separating of the retina which ophthalmoscopic examination, that with a Goldmann glass and that of echographic one have justified the enucleation for. The anatomopathological examination hasn't put in evidence any tumour and the subsequent clinical evolution has evidenced an orbital hydatid cyst.

Prolactin similar to ectopic pituitary isograft restores responsiveness in Snell dwarf mice

The effects of ovine prolactin (PRL) (2 x 5 IU a day) and an ectopic pituitary isograft on the responsiveness were examined using locomotor and exploratory activities as measures in PRL-growth-hormone-thyrotropin-deficient Snell dwarf mice (dw/dw). After 5 weeks of treatment, both PRL and the graft restored the two behavioural measures to normal levels. Results clearly demonstrate the involvement of PRL in global behavioural responsiveness and suggest a possible role for PRL in the changes induced by the graft.

m-Chlorophenylpiperazine enhances neophobic and anxious behaviour in mice

1-(3-Chlorophenyl)piperazine (mCPP) reduced novelty-seeking behaviour as well as the number of rears in mice confronted with a free exploratory test. Moreover, mCPP was found to decrease the time spent by mice in the lit box and the number of transitions in a two-box light/dark choice situation validated for the detection of anxiolytic or anxiogenic drugs. These results suggest that mCPP enhances emotional responses towards novel and aversive places. Since mCPP has been reported as a 5-HT1C receptor agonist, it can be hypothesized that increased activity of serotonin may play a role in regulating certain forms of emotional behaviour in animals.