Cadmium induces reactive oxygen species generation and lipid peroxidation in cortical neurons in culture

Cadmium is a toxic agent that it is also an environmental contaminant. Cadmium exposure may be implicated in some humans disorders related to hyperactivity and increased aggressiveness. This study presents data indicating that cadmium induces cellular death in cortical neurons in culture. This death could be mediated by an apoptotic and a necrotic mechanism. The apoptotic death may be mediated by oxidative stress with reactive oxygen species (ROS) formation which could be induced by mitochondrial membrane dysfunction since this cation produces: (a) depletion of mitochondrial membrane potential and (b) diminution of ATP levels with ATP release. Necrotic death could be mediated by lipid peroxidation induced by cadmium through an indirect mechanism (ROS formation). On the other hand, 40% of the cells survive cadmium action. This survival seems to be mediated by the ability of these cells to activate antioxidant defense systems, since cadmium reduced the intracellular glutathione levels and induced catalase and SOD activation in these cells.

Apoptosis and necrosis: two distinct events induced by cadmium in cortical neurons in culture

(1) Cadmium is an extremely toxic metal commonly found in industrial workplaces, a food contaminant and a major component of cigarette smoke. Cadmium can severely damage several organs, including the brain. In this work, we have studied both the cadmium toxicity on rat cortical neurons in culture and the possible protective effect of serum. (2) Our results indicate that: (1) cadmium is taken up by the neurons in a dose and serum dependent way; (2) cadmium, at concentrations from 1 micro M or 10 micro M (depending on the absence or the presence of serum) up to 100 micro M, decreases the metabolic capacity, which was evaluated by the XTT (tetrazolium salt) test; (3) cadmium induces apoptosis and LDH (lactate dehydrogenase) release in a dose dependent way; (4) in a serum-free medium, the cadmium-induced apoptosis is accompanied by caspase-3 activation; (5) both the caspase-3 activation and the cadmium-induced apoptosis are reversed by N-acethyl-Asp-Glu-Val-Asp-aldehyde (Ac-DEVD-CHO), a selective caspase-3 inhibitor, indicating that the caspase-3 pathway is involved in cadmium-induced apoptosis in cortical neurons; and (6) the cadmium concentrations which produce caspase-3 activation do not modify the intracellular ATP levels; however, higher cadmium concentrations lead to both intracellular ATP depletion and ATP release, but do not increase the caspase-3 activity, indicating that cadmium also produces cellular death by necrosis. (3) These results suggest that cadmium induces either apoptosis or necrosis in rat cortical neurons, depending on the cadmium concentration.

Improving treatment of chemotherapy-induced neutropenic fever by administration of colony-stimulating factors

BACKGROUND

Several randomized trials have tested the use of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in relieving chemotherapy-induced bone marrow suppression. However, the use of CSFs in the treatment of neutropenic fever remains virtually unexplored.

PURPOSE

This study evaluated the benefits of adding CSF therapy to the standard antibiotic treatments given to cancer patients for chemotherapy-induced neutropenic fever. The usefulness of CSFs was quantified in terms of reducing the following: (a) the duration of neutropenia, (b) the length of hospitalization, and (c) the overall cost of the treatment.

METHODS

A randomized trial was conducted to test whether the administration of either G-CSF or GM-CSF improved the outcome of standard antibiotic therapy (ceftazidime plus amikacin) in nonleukemic cancer patients with fever (> 38 degrees C) and grade IV neutropenia (absolute neutrophil count [ANC] < 500/mm3) induced by standard-dose chemotherapy. Of 121 patients who entered the trial, 39 received G-CSF (5 micrograms/kg body weight per day), 39 received GM-CSF (5 micrograms/kg body weight per day), and 43 received a placebo beginning just after the first dose of antibiotics. Treatments were continued for at least 5 days (7 days with clinically or microbiologically documented infections) or until 2 days after fever subsided and ANCs rose above 1000/mm3.

RESULTS

The median duration of grade IV neutropenia (ANC of < 500/mm3) was 2 days in both CSF arms and 3 days in the placebo arm (P < .001). The median duration of neutropenia with an ANC of less than 1000/mm3 was also significantly shorter in patients receiving G-CSF or GM-CSF (P < .001). The median duration of fever was similar in the three arms. The median hospital stay was 5 days (range, 5-14 days) in the G-CSF arm, 5 days (range, 5-10 days) in the GM-CSF arm, and 7 days (range, 5-34 days) in the placebo arm (P < .001). The median time on CSF was 4 days in both treatment arms. The mean cost of overall treatment was reduced by $1300-$1400 in the CSF arms compared with the placebo arm (P = .11 for G-CSF versus placebo; P = .06 for GM-CSF versus placebo; P = .7 for G-CSF versus GM-CSF).

CONCLUSIONS

Adding G-CSF or GM-CSF therapy to antibiotic treatment shortens the duration of neutropenia and the duration of hospitalization in patients with neutropenic fever. A statistically nonsignificant trend toward lower cost was observed in the CSF arms as compared with the placebo arm.

IMPLICATIONS

The benefits of CSFs to cancer patients with chemotherapy-induced neutropenic fever merit further evaluation in large randomized trials.

Tropomyosin IgE-positive results are a good predictor of shrimp allergy

BACKGROUND

Shrimp is a common cause of food allergy. Our aims were to determine the value of IgE antibodies in the diagnosis of shrimp allergy and to study red shrimp (Solenocera melantho) tropomyosin both as a new allergen and as a cross-reactive IgE-binding protein.

METHODS

We have studied 45 subjects. Skin prick test (SPT) was carried out in all subjects, and specific IgE (sIgE) to shrimp, recombinant and natural shrimp tropomyosins rPen a 1 and nPen m 1, recombinant Der p 10, and Dermatophagoides pteronyssinus was assessed by fluoroimmunoassay and/or immunoblotting. Double-blind, placebo-controlled food challenges were carried out to confirm diagnosis of shrimp allergy. Also, in vitro inhibition tests were performed to evaluate cross-reactivity.

RESULTS

Shrimp allergy was confirmed in 18 shrimp-allergic patients. Skin prick test and IgE antibodies to shrimp were positive in all shrimp-allergic patients; sIgE to rPen a 1 was detected in 98% of these patients. Of the 18 shrimp-tolerant patients, 61% had positive SPT to shrimp, 55% were IgE-positive to shrimp, and 33% showed IgE antibodies to rPen a 1. Determination of IgE to rPen a 1 yielded a positive predictive value of 0.72 and a negative predictive value of 0.91.

CONCLUSION

IgE levels to rPen a 1 provided additional value to the diagnosis of shrimp allergy. Some allergens in mite extract are recognized by patients who are allergic to shrimp, though their clinical relevance remains unknown.

Adsorption and desorption of copper and zinc in the surface layer of acid soils

The environmental and health effects of the contamination of soils by heavy metals depend on the ability of the soils to immobilize these contaminants. In this work, the adsorption and desorption of Cu and Zn in the surface layers of 27 acid soils were studied. Adsorption of Cu(II) from 157-3148 mumol L(-1) solutions was much greater than adsorption of Zn(II) from solutions at the same concentration. For both Cu and Zn, the adsorption data were fitted better by the Freundlich equation than by the Langmuir equation. Multiple regression analyses suggest that Cu and Zn adsorption depends to a significant extent on pH and CEC: for both metals these variables accounted for more than 80% of the variance in the Freundlich pre-exponential parameter K(F), and pH also accounted for 57% of the variance in 1/n for Zn and, together with carbon content, for 41% of the variance in 1/n for Cu. The percentage of adsorbed metal susceptible to desorption into 0.01 M NaNO3 was greater for Zn than for Cu, but in both cases depended significantly on pH, decreasing as pH increased. In turn, both pH(H2O) and pH(KCl) are significantly correlated with cation exchange capacity. Desorption of metal adsorbed from solutions at relatively low concentration (787 mumol L(-1)) exhibited power-law dependence on Kd, the quotient expressing distribution between soil and soil solution in the corresponding adsorption experiment, decreasing as increasing Kd reflected increasing affinity of the soil for the metal. The absence of a similarly clear relationship when metal had been adsorbed from solutions at relatively high concentration (2361 mumol L(-1)) is attributed to the scant between-soil variability of Kd at these higher concentrations. In general, adsorption was greater and subsequent desorption less in cultivated soils than in woodland soils.

Cloning and expression of a major allergen from Cupressus arizonica pollen, Cup a 3, a PR-5 protein expressed under polluted environment

BACKGROUND

This paper describes the cloning and expression of the Cupressus arizonica pollen protein Cup a 3. In addition, we present its modulation under polluted environmental conditions. Species of the Cupressaceae family are important because of their high sensitization prevalence.

METHODS

Cup a 3 cloning is based on the sequence of the homologous protein Jun a 3. Cup a 3 was expressed with good yield in the methylotropic yeast Pichia pastoris.

RESULTS

Recombinant Cup a 3 (rCup a 3) contains 199 amino acids, 10 potential phosphorylation sites and no glycosylation sites. By immunoblot 63% of cypress allergic patients had specific immunoglobulin E antibodies against rCup a 3 (n = 104). This major allergen is homologous to members of the pathogenesis-related proteins (PR-5 group) and contributes to the overall allergenicity of C. arizonica pollen. Our results show that the increased expression of Cup a 3 is dependent on the pollution in the area where the pollen has been collected, being higher under polluted conditions.

CONCLUSIONS

Cup a 3 is a PR-5 protein derived from C. arizonica pollen. The expression of the protein under polluted conditions has a direct incidence on the pollen allergenicity, as has been demonstrated by skin tests and Radioallergosorbent test inhibition.

Cytokine gene expression and release from epithelial cells. A comparison study between healthy nasal mucosa and nasal polyps

BACKGROUND

Epithelial cells release cytokines and they probably contribute to chronic inflammation detected in bronchial asthma, rhinitis and nasal polyposis.

OBJECTIVES

To investigate the effect of cultures on cytokine gene expression to compare epithelial cell cytokine release by both healthy nasal nucosa (HNM) and nasal polyps (NP), and the modulation by dexamethasone and to investigate which cytokines may promote eosinophil survival.

METHODS

Epithelials cells were cultured to confluence, human epithelial cell conditioned media generated with or without dexamethasone, and supernatants measured by ELISA. Cytokine gene expression was investigated by reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Fresh epithelial cells only expressed mRNA for intesleukin-8 (IL-8) and granulocyte macrophage-colony stimulating factor (GM-CSF) while cultured cells expressed mRNA for IL-1 beta, IL-6, IL-8, tumour necrosis factor-alpha (TNF alpha) and GM-CSF. Epithelial cells from NP significantly (P < 0.05) released more IL-8 (25431 +/- 3163 pg/mL), and GM-CSF (1229 +/- 391 pg/mL) than those from HNM (18604 +/- 1723 pg/mL for IL-8; and 611 +/- 98 pg/mL for GM-CSF). Dexamethasone 10 microM inhibited the release of all cytokines, this effect being similar (40-50%) in both HNM and NP, except for IL-6 which was higher in HNM. Eosinophil survival induced by epithelial cell secretions from both HNM and NP was strongly blocked by GM-CSF antibody while it was partially blocked by antibodies to TNF alpha and IL-8.

CONCLUSIONS

These findings suggest that although epithelial cell culture procedures may upregulate cytokine gene expression, nasal polyps may represent a more active inflammatory tissue by releasing more cytokines than healthy nasal mucosa this release being inhibited by steroids; and that, in addition to GM-CSF, other cytokines such as TNF alpha and IL-8, may also be involved in the promotion of eosinophil survival.

Long-term efficacy and tolerability of flutamide combined with oral contraception in moderate to severe hirsutism: a 12-month, double-blind, parallel clinical trial

OBJECTIVE

Our objective was to test the efficacy and tolerability of three doses of flutamide (125, 250, and 375 mg) combined with a triphasic oral contraceptive (ethynylestradiol/levonorgestrel) during 12 months to treat moderate to severe hirsutism in patients with polycystic ovary syndrome or idiopathic hirsutism.

DESIGN

We conducted a randomized, double-blind, placebo-controlled, parallel clinical trial.

PATIENTS

A total of 131 premenopausal women, suffering from moderate to severe hirsutism, were randomized to placebo or 125, 250, or 375 mg flutamide daily associated with a triphasic oral contraceptive pill. Hirsutism (Ferriman-Gallwey), acne and seborrhea (Cremoncini), and hormone serum levels were monitored at baseline and at 3 (except hormone serum levels), 6, and 12 months. Side effects and biochemical, hematological, and hepatic parameters were assessed.

METHODS

We used three-way ANOVA (subject, dose, and visit) with Scheffé adjustment for multiple comparisons or nonparametrical Friedman test and least-squares mean (paired data) and Kruskall-Wallis test for unpaired data analyses. We used chi(2) or Fisher's test for categorical data.

RESULTS

A total of 119 patients were included in the intention-to-treat analysis. All flutamide doses induced a significant decrease in hirsutism, acne, and seborrhea scores after 12 months compared with placebo without differences among dose levels. Similar related side effects were observed with placebo and 125 mg flutamide (12.5%), and slightly higher with 250 mg (17.3%) and 375 mg (21.2%). No statistically significant differences were observed either among doses or compared with placebo.

CONCLUSIONS

Flutamide at 125 mg daily during 12 months was the minimum effective dose to diminish hirsutism in patients with polycystic ovary syndrome or with idiopathic hirsutism.

Air pollution and cardiovascular admissions association in Spain: results within the EMECAS project

OBJECTIVE

To evaluate the short term effect of air pollution on cardiovascular admissions in 14 Spanish cities

METHODS

The period under study was from 1995 to 1999. Daily emergency admissions for all cardiovascular diseases (CVD) and heart diseases (HD) were obtained from hospital records, and the corresponding daily levels of particulates, SO2, NO2, CO, and ozone were recorded. The magnitude of association was estimated using Poisson generalised additive models controlling for confounding and overdispersion. For each cause, lagged effects, up to three days, of each pollutant were examined and combined estimates were obtained. For ozone the analyses were restricted to the warm period. One and two pollutant models were performed.

RESULTS

Associations were more consistent in lag 0 (concurrent day) and 1 (lag 0-1), except in the case of ozone where there was a more delayed relation (lag 2-3). For combined estimates an increase of 10 microg/m3 in the PM10 levels in lag 0-1 was associated with an increase of 0.9% (95% CI: 0.4 to 1.5%) in the number of hospital admissions for CVD, and 1.6% (0.8 to 2.3%) for HD. For ozone the corresponding estimates for lag 2-3 were 0.7% (0.3 to 1.0) for CVD, and 0.7% (0.1 to 1.2) for HD. An increase of 1 mg/m3 in CO levels was associated with an increase of 2.1% (0.7 to 3.5%) in CVD admissions, and 4.2% (1.3 to 7.1%) in HD admissions. SO2 and NO2 estimates were more sensitive in two pollutant models

CONCLUSIONS

A short term association between increases in daily levels of air pollutants and the number of daily admissions for cardiovascular diseases, with specificity for heart diseases, has been described in Spanish cities.

Differentiation "in vitro" of primary and immortalized porcine mesenchymal stem cells into cardiomyocytes for cell transplantation

Cell transplantation to regenerate injured tissues is a promising new treatment for patients suffering several diseases. Bone marrow contains a population of progenitor cells known as mesenchymal stem cells (MSCs), which have the capability to colonize different tissues, replicate, and differentiate into multilineage cells. Our goal was the isolation, characterization, and immortalization of porcine MSCs (pMSCs) to study their potential differentiation "in vitro" into cardiomyocytes. pMSCs were obtained from the aspirated bone marrow of Large-White pigs. After 4 weeks in culture, adherent cells were phenotypically characterized by flow cytometry and immunochemistry by using monoclonal antibodies. Primary pMSCs were transfected with the plasmid pRNS-1 to obtain continuous growing cloned cell lines. Fresh pMSCs and immortalized cells were treated with 5-azacytidine to differentiate them into cardiomyocytes. Flow cytometry analysis of isolated pMSCs demonstrated the following phenotype, CD90(pos), CD29(pos), CD44(pos), SLA-I(pos), CD106(pos), CD46(pos) and CD45(neg), CD14(neg), CD31(neg), and CD11b(neg), similar to that described for human MSC. We derived several stable immortalized MSC cell lines. One of these, called pBMC-2, was chosen for further characterization. After "in vitro" stimulation of both primary or immortalized cells with 5-azacytidine, we obtained different percentages (30%-50%) of cells with cardiomyocyte characteristics, namely, positive for alpha-Actin and T-Troponin. Thus, primary or immortalized pMSCs derived from bone marrow and cultured were able to differentiate "ex vivo" into cardiac-like muscle cells. These elements may be potentials tools to improve cardiac function in a swine myocardial infarct model.

Comparison of the role of nasal polyp and normal nasal mucosal epithelial cells on in vitro eosinophil survival. Mediation by GM-CSF and inhibition by dexamethasone

Eosinophilic infiltration of the respiratory mucosa is considered an inflammatory hallmark of allergic rhinitis, bronchial asthma and nasal polyposis. However, the mechanisms involved in this infiltration have not yet been totally elucidated. The objective of this study was to investigate and compare the influence of epithelial cell secretions from both nasal polyps (NP) and normal nasal mucosa (NM) on in vitro eosinophil survival. Epithelial cells were identified by microscopy and immunohistochemistry, cultured to confluence, and human epithelial cell conditioned media (HECM) was generated from cultures. Eosinophils were isolated at high viability and purity (> 90%) from peripheral blood and incubated with HECM. HECM from both NM and NP increased eosinophil survival in a dose-dependent manner, this effect being maximal at a concentration of 25% for NM (73.4% +/- 5.5%, n = 26, P < 0.001) and of 10% for NP (74.5% +/- 8.4%, n = 18, P < 0.001). Incubation of monoclonal antibody to human GM-CSF with HECM, neutralized the induction of eosinophil survival by HECM from both NM and NP. HECM from NP contained higher concentrations of GM-CSF (111 +/- 25.4 pg/ml, n = 17) than HECM from NM (97.1 +/- 15.2 pg/ml, n = 8), without reaching statistical significance. Pre-incubation of dexamethasone with eosinophils also blocked HECM-induced eosinophil survival from both NM (10(-8)-10(-5) M; IC50 = 9.5 nM) and NP (10(-7)-10(-5) M; IC50 = 83 nM). These results suggest that: firstly eosinophil infiltration into the respiratory mucosa during allergic reaction and nasal polyposis may be modulated at least in part by GM-CSF from epithelial cells; and secondly epithelial cells from NP might have a more potent effect on inducing eosinophil infiltration of the respiratory mucosa than epithelial cells from NM. Finally, we may consider this as a reliable in vitro model to compare the role of epithelial cells from inflammatory (NP) and non-inflammatory (NM) tissue in respiratory inflammation.

Differential c-Fos and caspase expression following kainic acid excitotoxicity

Caspases play crucial roles in the inflammatory response and in the cell pathway leading to apoptosis. Caspase 1 (ICE), 2 (Nedd2), 3 (CPP32), 6 (Mch2) and 8 (Mch5, FLICE) expression was examined using immunohistochemistry in the brains of rats and gerbils following systemic administration of kainic acid (KA). The distribution of caspase expression was compared with the distribution of c-Fos expression, a transcription factor that is produced in response to the excitotoxic insult. Strong caspase 2 immunoreactivity was found in microglia up to 6 h following KA administration. Focal strong expression of caspases 1, 2, 3, 6 and 8 was observed in astrocytes and neurons, from 12 to 48 h after KA injection, in areas in which a number of neurons were committed to die. This distribution was in contrast with the generalised distribution of c-Fos expression following KA administration. Only a minority of neurons in the entorhinal cortex, amygdala and hilus, but a majority of neurons in selected thalamic nuclei, exhibited strong caspase expression in KA-treated rats. Similar findings, although minimised, were observed in KA-treated gerbils. Double-labelling caspase immunohistochemistry and in situ end-labelling of nuclear DNA fragmentation disclosed co-localisation of strong caspase expression and nuclear DNA breaks in a small percentage of neurons but no co-localisation in astrocytes. Western blots of entorhinal cortex and neocortex homogenates showed cleavage of certain caspase substrates in KA-treated rats. The intensity of the bands corresponding to lamin B and protein kinase C-delta was decreased in the entorhinal cortex following KA administration. Several bands appeared in the entorhinal cortex and neocortex paragraph signin Western blots processed for the demonstration of poly(ADP-ribose) polymerase (PARP), thus indicating that other proteases, in addition to caspases, cleaved PARP following KA administration. Taken together, these findings indicate that KA excitotoxicity triggers caspase expression which, although predominant in regions subjected to irreversible cell damage, has only a weak association with the presence of nuclear DNA breaks and neuron cell death. Although these results suggest caspase activation, further studies have to be performed to elucidate whether caspase activation plays a crucial role in KA excitotoxicity.

NF-kB immunoreactivity is observed in association with beta A4 diffuse plaques in patients with Alzheimer's disease

Transcription factor NF-kB is widely expressed in the nervous system and, particularly, in synaptic terminals. Increased NF-kB expression in synaptosomes has been observed as a result of activity, and beta A4 deposition. In the present study we have examined NF-kB immunoreactivity, by means of NF-kB p65 immunohistochemistry, in the brains of seven patients with Alzheimer's disease, two patients with Creutzfeldt-Jakob disease associated with PrP amyloid deposition, and seven age-matched controls. Our purpose was to examine possible NF-kB induction associated to beta A4 or PrP deposition in these diseases. Punctate NF-kB immunoreactivity was constantly found in the neuropil of diffuse beta A4 deposits but not in dystrophic neurites of senile plaques. In addition, NF-kB immunoreactivity was found in the nuclei of neurons, but not in the nuclei of reactive astrocytes, in the vicinity of diffuse plaques, thus suggesting NF-kB translocation to the nucleus. Finally, a few neurons with neurofibrillary degeneration showed increased cytoplasmic NF-kB immunoreactivity probably secondary to abnormal compartmentation or impaired transport of NF-kB. No similar modifications in NF-kB immunoreactivity were observed in association with PrP deposits in patients with Creutzfeldt-Jakob disease. Since it has been suggested that the presence of NF-kB in synapses may indicate the existence of a new pathway of gene transcription, the present results support the concept that this pathway may be activated by the deposition of beta A4 in diffuse plaques in Alzheimer's disease.

Ras-guanine nucleotide exchange factor sos2 is dispensable for mouse growth and development

The mammalian sos1 and sos2 genes encode highly homologous members of the Son-of-sevenless family of guanine nucleotide exchange factors. They are ubiquitously expressed and play key roles in transmission of signals initiated by surface protein tyrosine kinases that are transduced into the cell through the action of membrane-associated Ras proteins. Recent reports showed that targeted disruption of the sos1 locus results in embryonic lethality. To gain insight into the in vivo function of sos2, we disrupted its catalytic CDC25-H domain by means of gene targeting techniques. Mating among heterozygous sos2(+/-) mice produced viable sos2(-/-) offspring with a normal Mendelian pattern of inheritance, indicating that the loss of sos2 does not interfere with embryo viability in the uterus. Adult homozygous mutant sos2(-/-) mice reached sexual maturity at the same age as their wild-type littermates, and both male and female null mutants were fertile. Histopathological analysis showed no observable differences between mutant and wild-type mice. Our results show that unlike the case for sos1, sos2 gene function is dispensable for normal mouse development, growth, and fertility.

Bcl-2 and Bax protein expression in Alzheimer's disease

Beta-amyloid deposition and neurofibrillary degeneration are important pathological findings in the brains of patients with Alzheimer's disease (AD). In the present study, we have examined Bcl-2 and Bax immunoreactivity in the hippocampus of AD cases, with special attention to the possible relationship between Bcl-2 and Bax immunoreactivity, and neurofibrillary degeneration and senile plaques. Different antibodies were used, including Bcl-2 (N-19), Bcl-2 (BioGenex), Bax (P-19) and Bax (N-20), and their specificity was tested on Western blots of brain homogenates. No differences between Bcl-2 and Bax immunoreactivity in tangle-bearing and non-tangle-bearing neurons were observed, thus suggesting that Bcl-2 and Bax do not participate in tangle formation. Overexpression of Bcl-2 protein in reactive glial cells surrounding senile plaques suggests that Bcl-2 may play a role in the survival of reactive glia. On the other hand, overexpression of Bax immunoreactivity in dystrophic neurites of senile plaques suggests that Bax is associated with neurite degeneration in senile plaques. Finally, Bax (P-19), but not Bax (N-20), immunoreactivity was localized in amyloid fibrils of senile plaques. Since Western blots to Bax (P-19) recognize multiple bands in addition to the expected band of about 21 kDa, it is suggested that Bax (P-19) immunoreactivity of amyloid fibrils is not specific.

Comparative study of the effects of different glucocorticosteroids on eosinophil survival primed by cultured epithelial cell supernatants obtained from nasal mucosa and nasal polyps

BACKGROUND

Supernatants from epithelial cell cultures enhance eosinophil survival in vitro, this effect being abrogated by previous incubation of eosinophils with glucocorticosteroids. This property has resulted in the development of an in vitro test to compare the potency of these drugs. A comparative study was performed with dexamethasone, methylprednisolone, deflazacort, and budesonide.

METHODS

Human epithelial cell conditioned media (HECM) was generated from cultured epithelial cells obtained from healthy nasal mucosa and polyps. Eosinophils isolated from the peripheral blood were incubated with different corticosteroids for one hour before the addition of HECM. The inhibitory potency of the four steroids on the eosinophil survival index was compared using the concentration of steroid causing 50% inhibition (IC50).

RESULTS

Eosinophil survival was increased by HECM from both healthy nasal mucosa and polyps. All four steroids blocked HECM-induced eosinophil survival in a dose-dependent manner. On healthy nasal mucosa methylprednisolone was the least potent (IC50 = 536 nM), deflazacort (IC50 = 264 nM) was twice as potent as methylprednisolone, while budesonide and dexamethasone were approximately nine times as potent (both IC50 = 58 nM). When potency was evaluated on the promoting effects of the HECM obtained from nasal polyps, the inhibitory potencies were lower and consequently the IC50 values were higher when compared with HECM generated from healthy nasal mucosa: methylprednisolone (IC50 = 546 nM), deflazacort (IC50 = 390 nM), dexamethasone (IC50 = 76 nM), and budesonide (IC50 = 78 nM).

CONCLUSIONS

The potencies of glucocorticosteroids can be compared by evaluating their effects on the survival of eosinophils previously primed by supernatants obtained from epithelial cell culture. The different effects of steroids on eosinophils primed by HECM obtained from healthy nasal mucosa compared with HECM obtained from nasal polyps suggest that polyps might represent more active tissue which is relatively resistant to treatment with corticosteroids.

Bcl-2, Bax and Bcl-x expression following hypoxia-ischemia in the infant rat brain

Severe hypoxic-ischemic cerebral damage was produced in 8-day-old rats following permanent bilateral carotid artery occlusion and 15 min of ischemia. Cellular damage consisted of early necrosis and appearance of cells with apoptotic-like morphology (karyorrhectic cells) and cells with granular chromatin degeneration in the cerebral cortex, hippocampus, thalamus, stratum and amygdala. Expression of Bcl-2, Bax and Bcl-x was examined in control and hypoxic-ischemic rats using immunohistochemistry and Western blotting. Members of the Bcl-2 family were expressed in the vast majority of, if not all, neurons in control pups. Bcl-2, Bax and Bcl-x immunoreactivity decreased in necrotic cells, but about 60% of cells with apoptotic-like morphology and cells with granular chromatin degeneration were stained with antibodies to Bcl-2, Bax or Bcl-x. Although the total number of stained cells decreased with time, recruitment of cells with apoptotic morphology and cells with granular chromatin degeneration was still found up to 48 h. Western blots showed a band at about p28 and p21, respectively for Bcl-2 and Bax in control and hypoxic-ischemic pups at 6, 12 and 24 h. Two bands at about p37 and p30, representing Bcl-xL and Bcl-xS, respectively, were found in samples stained with antibodies to Bcl-x. No gross changes in the intensity of these bands were observed in ischemic pups at 6, 12 and 24 h, except for a slight decrease in Bcl-2 at 24 h, and a slight and inconstant increase of the putative Bcl-xS at 12 h. These results suggest that Bcl-2, Bax, Bcl-xL and Bcl-xS do not play a leading role in the fate of damaged nerve cells following a severe hypoxic-ischemic insult of the developing brain.

Induction chemotherapy with paclitaxel, cisplatin and 5-fluorouracil for squamous cell carcinoma of the head and neck: long-term results of a phase II trial

BACKGROUND

The aim of this study was to evaluate the efficacy and toxicity of a combination of paclitaxel, cisplatin and 5-fluorouracil (PPF) as induction chemotherapy in patients with locally advanced squamous cell carcinoma of the head and neck (SCCHN).

METHODS

Seventy patients with previously untreated stage III-IV SCCHN were included in this phase II trial. Induction treatment consisted of a maximum of three outpatient courses of paclitaxel 175 mg/m(2) as a 3-h infusion on day 1, cisplatin 100 mg/m(2) on day 2, and 5-fluorouracil (5-FU) 500-750 mg/m(2)/day as a 24-h continuous infusion on days 2-6, repeated every 3 weeks. The 5-FU dose was reduced from 750 mg/m(2)/day to 500 mg/m(2)/day due to the excessive toxicity observed in the first 14 patients enrolled. Local treatment consisted of radiotherapy and/or surgery.

RESULTS

Two-hundred-and-one cycles were administered to 70 patients. The main toxicities of PPF were neutropenia (grade 4, 14%; febrile neutropenia, 4%), peripheral neuropathy (grade 2-3, 14%) and catheter-associated venous thrombosis (7%). There were three early deaths (two from neutropenic sepsis and one from pulmonary embolism), and 13 patients required hospitalization due to toxicity. Other side effects included mucositis, anorexia, diarrhea, myalgias and alopecia. The overall response rate to PPF was 88%, including 59% complete responses (CR) and 29% partial responses. The CR rates at the primary tumor and neck lymph nodes were 74% and 62%, respectively. With a median follow-up of 51 months (range 40-63 months), the estimated 5-year time-to-disease progression and overall survival rates were 56% and 44%, respectively.

CONCLUSIONS

The PPF regimen has major antitumor activity and is associated with manageable toxicity as induction treatment in SCCHN patients. The high complete response rate and favorable long-term outcome justify further evaluation of this chemotherapy combination.

Bcl-2, Bax and Bcl-x expression following kainic acid administration at convulsant doses in the rat

Neuronal death was produced in the CA1 and CA3 areas of the hippocampus, amygdala, and piriform and entorhinal cortices after intraperitioneal administration of kainic acid at convulsant doses to adult rats. To assess the involvement of members of the Bcl-2 family in cell death or survival, immunohistochemistry, western and northern blotting to Bcl-2, Bcl-x and Bax, and in situ hybridization to Bax were examined at different time-points after kainic acid treatment. Members of the Bcl-2 family were expressed in the cytoplasm of pyramidal neurons in the hippocampus, and in a subset of neurons of the piriform and the entorhinal cortices, amygdala and neocortex in the normal adult brain. Dying neurons in the pyramidal cell layer of CA1 and CA3 areas, entorhinal and piriform cortices, and amygdala also expressed Bcl-2, Bax and Bcl-x following excitotoxicity, although many dying cells did not. In addition, a number of cells in the affected areas showed Bax immunoreactivity in their nuclei at 24-48 h following kainic acid administration, thus indicating Bax nuclear translocation in a subset of dying cells. Western blots disclosed no modifications in the intensity of the bands corresponding to Bcl-2, Bcl-x and Bax, between control and kainic acid-treated rats. No modifications in the intensity of the bcl-2 messenger RNA band on northern blots was observed in kainic acid-treated rats. However, a progressive increase in the intensity of the bax messenger RNA band was found in kainic acid-treated rats at 6 h, 12 h and 24 h following kainic acid administration. Interestingly, a slight increase in Bax immunoreactivity was observed in the cytoplasm of neurons of the dentate gyrus at 24-48 h, a feature which matches the increase of bax messenger RNA in the same area, as shown by in situ hybridization at 12-24 h following kainic acid injection. The present results suggest that cell death or survival does not correlate with modifications of Bcl-2, Bax and Bcl-x protein, and messenger RNA expression, but rather that kainic acid excitotoxicity is associated with Bax translocation to the nucleus in a subset of dying cells.

Staurosporine- and H-7-induced cell death in SH-SY5Y neuroblastoma cells is associated with caspase-2 and caspase-3 activation, but not with activation of the FAS/FAS-L-caspase-8 signaling pathway

Apoptotic cell death is induced in SH-SY5Y neuroblastoma cells following exposure to the protein kinase inhibitors staurosporine (100 nM) and 1-(5-Isoquinolinesulfonyl)-2-methylpiperazine: H-7 (100 microM). This is associated with reduced levels of PARP 117 kDa and with the concomitant formation of PARP-cleaved products of 89 kDa that result from caspase-3 activation. The process is inhibited with DEVD-fmk, a potent caspase-3 (and caspase-8) inhibitor, thus indicating that staurosporine- and H-7-induced cell death in SH-SY5Y is mediated by caspase activation. Increased caspase-2- and caspase-3-like activities, but not caspase-9-like activity, were demonstrated by monitoring proteolysis of the corresponding colorimetric substrates. Caspase-2 activity peaked at 6 h, whereas caspase-3 peaked at 12 h in parallel with the maximal loss of cell viability. No modifications in the expression levels of Fas and Fas-L were observed by Western blotting. Furthermore, no activation of caspase-8 was elicited by colorimetric assays through the process of apoptosis of neuroblastoma cells. These findings indicate that the Fas/Fas-L-caspase-8 pathway of cell death signaling is not involved in staurosporine- and H-7-induced apoptosis in SH-SY5Y neuroblastoma cells.

Pertussis toxin blocks the action of morphine, norepinephrine and clonidine on isolated guinea-pig ileum

Administration of pertussis toxin (60 micrograms/kg i.p.) to guinea-pigs blocked the ability of morphine, norepinephrine and clonidine to inhibit electrically stimulated contractions in the isolated ileum. The toxin reached its maximum effect 6 days after its administration. The effect of the toxin was reversible; a slow but full recovery of the response to morphine was observed in ilea from guinea-pigs treated with toxin 18 days before the experiment. It is suggested, based on the known action of pertussis toxin, that inhibition of adenylate cyclase through Ni (guanine-nucleotide regulatory protein) is involved in the acute action of morphine, norepinephrine and clonidine in the motoneurons of the myenteric plexus of the ileum.

Dose rate constants for 125I, 103Pd, 192Ir and 169Yb brachytherapy sources: an EGS4 Monte Carlo study

An exhaustive revision of dosimetry data for 192Ir, 125I, 103Pd and 169Yb brachytherapy sources has been performed by means of the EGS4 simulation system. The DLC-136/PHOTX cross section library, water molecular form factors, bound Compton scattering and Doppler broadening of the Compton-scattered photon energy were considered in the calculations. The absorbed dose rate per unit contained activity in a medium at 1 cm in water and air-kerma strength per unit contained activity for each seed model were calculated, allowing the dose rate constant (DRC) A to be estimated. The influence of the calibration procedure on source strength for low-energy brachytherapy seeds is discussed. Conversion factors for 125I and 103Pd seeds to obtain the dose rate in liquid water from the dose rate measured in a solid water phantom with a detector calibrated for dose to water were calculated. A theoretical estimate of the DRC for a 103Pd model 200 seed equal to 0.669 +/- 0.002 cGy h(-1) U(-1) is obtained. Comparison of obtained DRCs with measured and calculated published results shows agreement within 1.5% for 192Ir, 169Yb and 125I sources.

Bcl-2, Bax, and Bcl-x expression in the CA1 area of the hippocampus following transient forebrain ischemia in the adult gerbil

Delayed neuronal death was produced in the CA1 area of the hippocampus following 5 min of forebrain ischemia in adult gerbils. Immunohistochemistry and Western blotting to Bcl-2, Bax, and Bcl-x was examined in control (age-matched, non-operated and sham-operated) and ischemic gerbils. Bcl-2 immunoreactivity was low in CA1 neurons, but Bax was highly expressed in CA1 neurons of control gerbils. Moderate Bcl-x immunoreactivity was observed in control CA1 neurons. Strong Bcl-2 and Bcl-x immunoreactivity was found in CA1 neurons following ischemia. Bcl-2, Bax, and Bcl-x were localized in dying cells, thus suggesting that expression of Bcl-2 was not sufficient to prevent nerve cells from dying. Although the Bcl-x antibody does not discriminate between Bcl-xL and Bcl-xS content in tissue sections, Western blots disclosed a marked increase in the intensity of the band corresponding to Bcl-xS, but not of the band corresponding to Bcl-xL in ischemic hippocampi, thus indicating that the increase in Bcl-xS is associated with delayed cell death following transient forebrain ischemia in the adult gerbil.

Nicotinic receptors mediate the release of amino acid neurotransmitters in cultured cortical neurons

Nicotine stimulation of cortical neurons obtained from gestation day 19 rats provoked a dose-dependent release of aspartate, glutamate, glycine and GABA, indicating a functional role for the nicotinic receptor in this model. This release was exclusively Ca2+-dependent (vesicular release) in the case of aspartate and dual Ca2+-dependent and Ca2+-independent) for glutamate, glycine and GABA. Nicotine also raised the membrane potential and the intracellular calcium concentration. These effects were specific, since they were reversed by hexamethonium, an antagonist of the nicotinic receptor. It was shown that L, N, and P/Q type Ca2+ channels are involved in nicotine-mediated Ca2+ entry into cortical neurons. Evaluation of the effects of nicotine on Ca2+ entry in isolated cells showed that 100% of the cells responded to nicotine, although the intensity of the response was variable: 63% of the neurons showed an increase in intracellular Ca(2+) of 152 +/- 5 grey levels, 25% of 88 +/- 12 grey levels and 12% of 48 +/- 1 grey levels. Tetrodotoxin, which blocks voltage-dependent Na(+) channels, completely reversed nicotine-induced Ca2+ entry into single cells. This suggests that the Ca2+ increment is mediated by opening of Ca2+ channels and not by the nicotinic receptor.

Clinical features of adrenal insufficiency in patients with acquired immunodeficiency syndrome

OBJECTIVE

Adrenal insufficiency (AI) is a well known complication of AIDS. However, the clinical and biochemical features of AI in HIV infected patients have not been extensively studied.

DESIGN

A retrospective clinical study.

PATIENTS

We reviewed clinical records of 74 AIDS patients with clinical and/or biochemical indications of AI who underwent Synacthen testing in order to determine adrenocortical function during a 5-year period.

MEASUREMENTS

AI was diagnosed when cortisol levels failed to rise above 496 nmol/l at any time during the test. Cortisol was measured by RIA.

RESULTS

Sixteen patients (22%) were diagnosed with AI. Most were young males and all of them had a known risk factor, principally i.v. drug users. The main complaint was fatigue. Hyponatraemia or hyperkalaemia were uncommon. All of them were severely immunosuppressed, with AIDS-defining conditions from at least 6 months before the diagnosis of AI, and had been diagnosed with at least one disease that has been reported to produce AI in AIDS patients. Survival was poor. Thirteen of these patients (81%) died within 6 months. Basal cortisol levels were lower than 275 nmol/l in 75% of patients with AI but in only 2% of the group of 58 patients who had normal adrenal responses to Synacthen.

CONCLUSIONS

Adrenal insufficiency features in AIDS patients with advanced disease, without specific findings and with a history of previous opportunistic diseases. Basal cortisol values at 0830 h lower than 275 nmol/l are highly suggestive of adrenal insufficiency in patients with AIDS.