Meningoradiculitis due to varicella zoster virus reactivation in a patient treated with ixekizumab.

INTRODUCTION: Ixekizumab is a recently developed biopharmaceutical used since 2016 in the US and Europe for the treatment of plaque psoriasis. Few adverse effects have been reported in the literature and ixekizumab is not known to increase the risk of viral reactivation. Herein we report the case of an immunocompetent female patient treated with ixekizumab who presented meningoradiculitis due to varicella zoster virus (VZV) reactivation. PATIENTS AND METHODS: A 51-year-old woman, treated with ixekizumab for psoriasis, consulted in March 2018 for left hemicrania headache associated with left facial paralysis, but without fever. Brain MRI scans revealed cerebral venous thrombosis of the superior sagittal sinus. Analysis of cerebrospinal fluid (CSF) revealed lymphocytic meningitis and positive VZV-PCR. PCR blood assay for VZV was negative. Blood concentrations of anti-VZV IgG antibody increased while Anti-VZV IgM antibodies remained negative. The final diagnosis was VZV meningoradiculitis complicated by cerebral thrombophlebitis. The absence of skin rash, the rapid increase in anti-VZV IgG antibodies, the absence of anti-VZV IgM antibodies, and the negative blood PCR assay suggested viral reactivation rather than primary infection. The patient received acyclovir and coumadin and her condition improved rapidly. After multidisciplinary discussion, ixekizumab was reintroduced together with valacyclovir prophylaxis. CONCLUSION: This case raises the question of the risk of viral reactivation during treatment with an IL-17 inhibitor and with biologics in general. Neurological and vascular complications of VZV may occur without skin lesions and their occurrence during ixekizumab therapy must be investigated by PCR testing of CSF for VZV DNA.

Impacts on human mortality due to reductions in PM10 concentrations through different traffic scenarios in Paris, France.

OBJECTIVES: Air pollution is a well-known burden for population health and health systems worldwide. Reduction in air pollution is associated with improvements in mortality and rates of respiratory, cardiovascular and other diseases. Though air quality is a problem globally, efforts to lower air pollutant concentrations are usually regional or local. In industrialized countries, most urban air pollution is caused by vehicles, suggesting reductions in traffic would result in reductions of pollution. However, detailed data on how such reductions can be achieved and impact public health is just beginning to emerge, and other influencing factors, including vehicle flow or urban landscape are largely unaccounted for. METHODS: We utilized a unique combination of vehicle emission measurements combined with simulations of traffic and vehicle variations, as well as urban topographies, to quantify health impacts of PM10 reduction in a single district of Paris, France, for various methods of traffic improvement. Here we rank and evaluate improvements in non-accidental mortality for thirteen possible scenarios to reduce traffic related PM10 emissions. RESULTS: The maximum impact scenario requires all passenger vehicles to meet Euro 5 standards and excludes diesel vehicles, resulting in long-term decreases in non-accidental mortality of 148.79 people per year, or 104.40 per 100,000 people. Similar reductions hold for the scenario requiring a completely electric passenger fleet, with long-term annual reductions of 137.14 premature mortalities. Removing all diesel vehicles is the third most impactful scenario, preventing 135.55 deaths yearly. DISCUSSION: PARTLESS provides comparisons between thirteen different traffic-related air quality reduction mechanisms in terms of improvements in mortality rates. Improving emissions standards, increasing electric vehicle use and removing diesel vehicles can prevent more than 148 deaths per year in this district alone. Further improvements in mortality reduction may require changes to the composition of vehicle components, asphalt or to the management of resuspended particulate matter.

Cognitive impairment and morphological changes in the dorsal hippocampus of very old female rats.

The hippocampus, a medial temporal lobe structure necessary for the formation of spatial memory, is particularly affected by both normal and pathologic aging. In previous studies, we observed a significant age-related increase in dopaminergic neuron loss in the hypothalamus and the substantia nigra of female rats, which becomes more conspicuous at extreme ages. Here, we extend our studies by assessing spatial memory in 4-6 month-old (young), 26-month-old (old) and 29-32-month-old (senile) Sprague-Dawley female rats as well as the age-related histopathological changes in their dorsal hippocampus. Age changes in spatial memory performance were assessed with a modified version of the Barnes maze test. We employed two probe trials (PTs), one and five days after training, respectively, in order to evaluate learning ability as well as short-term and longer-term spatial memory retention. A set of relevant hippocampal cell markers was also quantitated in the animals by means of an unbiased stereological approach. The results revealed that old rats perform better than senile rats in acquisition trials and young rats perform better than both aging groups. However, during short-term PT both aging groups showed a preserved spatial memory while in longer-term PT, spatial memory showed deterioration in both aged groups. Morphological analysis showed a marked decrease (94-97%) in doublecortin neuron number in the dentate gyrus in both aged groups and a reduction in glial fibrillary acidic protein-positive cell number in the stratum radiatum of aging rats. Astroglial process length and branching complexity decreased in aged rats. We conclude that while target-seeking activity and learning ability decrease in aged females, spatial memory only declines in the longer-term tests. The reduction in neuroblast number and astroglial arborescence complexity in the dorsal hippocampus are likely to play a role in the cognitive deficits of aging rats.

Pioderma gangrenoso tras cirugía de cadera / Pyoderma gangrenosum following a hip surgical procedure

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Rituximab therapy for systemic vasculitis associated with rheumatoid arthritis: Results from the AutoImmunity and Rituximab Registry.

OBJECTIVE: Rituximab improves articular symptoms in rheumatoid arthritis (RA) and it recently has been shown to be an effective induction therapy for antineutrophil cytoplasmic antibody-associated vasculitis. We assessed the efficacy and safety of rituximab in a real-life clinical setting among patients with systemic rheumatoid vasculitis (SRV). METHODS: We analyzed data from the AutoImmunity and Rituximab registry, which includes patients with autoimmune diseases treated with rituximab. RESULTS: Of the 1,994 patients with RA enrolled in the registry, 17 were treated with rituximab for active SRV. At baseline, the mean Birmingham Vasculitis Activity Score for RA (BVAS/RA) was 9.6, with a mean prednisone dosage of 19.2 mg/day. After 6 months of rituximab therapy, 12 patients (71%) achieved complete remission of their vasculitis, 4 had a partial response, and 1 died with uncontrolled vasculitis. Mean BVAS/RA was reduced to 0.6 and mean prednisone dosage to 9.7 mg/day. At 12 months, 14 patients (82%) were in sustained complete remission. Severe infection occurred in 3 patients, corresponding to a 6.4 per 100 patient-years rate. In the 6 patients who received further rituximab as maintenance therapy between months 6 and 12, no relapse of vasculitis was observed. However, among the 9 patients who did not, a relapse was observed in 3 patients who were treated with methotrexate alone. Remission was reestablished by reintroducing rituximab in 2 cases. CONCLUSION: Complete remission of SRV was achieved in nearly three-fourths of patients receiving rituximab in daily practice, with a significant decrease in daily prednisone dosage and an acceptable toxicity profile. Rituximab represents a suitable therapeutic option to induce remission in SRV, but maintenance therapy seems to be necessary.

Exogenous growth hormone attenuates cognitive deficits induced by intermittent hypoxia in rats.

Sleep disordered breathing (SDB), which is characterized by intermittent hypoxia (IH) during sleep, causes substantial cardiovascular and neurocognitive complications and has become a growing public health problem. SDB is associated with suppression of growth hormone (GH) secretion, the latter being integrally involved in the growth, development, and function of the CNS. Since GH treatment is able to attenuate neurocognitive deficits in a hypoxic-ischemic stroke model, GH, GH receptor (GHR) mRNA expression, and GH protein expression were assessed in rat hippocampus after exposures to chronic sustained hypoxia (CH, 10% O(2)) or IH (10% O(2) alternating with 21% O(2) every 90 s). In addition, the effect of GH treatment (50 µg/kg daily s.c. injection) on erythropoietin (EPO), vascular endothelial growth factor (VEGF), heme oxygenase-1 (HO-1), and GLUT-1 mRNA expression and neurobehavioral function was assessed. CH significantly increased GH mRNA and protein expression, as well as insulin-like growth factor-1 (IGF-1). In contrast, IH only induced a moderate increase in GH mRNA and a slight elevation in GH protein at day 1, but no increases in IGF-1. CH, but not IH, up-regulated GHR mRNA in the hippocampus. IH induced marked neurocognitive deficits compared with CH or room air (RA). Furthermore, exogenous GH administration increased hippocampal mRNA expression of IGF-1, EPO, and VEGF, and not only reduced IH-induced hippocampal injury, but also attenuated IH-induced cognitive deficits. Thus, exogenous GH may provide a viable therapeutic intervention to protect IH-vulnerable brain regions from SDB-associated neuronal loss and associated neurocognitive dysfunction.

Restorative effect of intracerebroventricular insulin-like growth factor-I gene therapy on motor performance in aging rats.

Insulin-like growth factor-I (IGF-I) is a powerful neuroprotective molecule in the brain and spinal cord. We have previously shown that intracerebroventricular (i.c.v.) IGF-I gene therapy is an effective strategy to increase IGF-I levels in the cerebrospinal fluid (CSF). Since aging in rats is associated with severe motor function deterioration, we implemented i.c.v. IGF-I gene therapy in very old rats (30-31 months) and assessed the beneficial impact on motor performance. We used recombinant adenovectors (RAds) expressing either green fluorescent protein (GFP) or rat IGF-I. Injection in the lateral or fourth ventricle led to high transgene expression in the ependymal cell layer in the brain and cervical spinal cord. RAd-IGF-I-injected rats but not RAd-GFP-injected controls, showed significantly increased levels of CSF IGF-I. Motor tests showed the expected age-related decline in aged rats. Seventeen-day IGF-I gene therapy induced a significant improvement in motor performance in the aged but not in the young animals. These results show that IGF-I is an effective restorative molecule in the aging brain and spinal cord. The data also reveal that the ependymal route constitutes a promising approach for implementing protective IGF-I gene therapy in the aging CNS.

Embarazo como factor de riesgo de hospitalización y muerte en la pandemia por influenza A (H1N1) en Paraguay / Pregnancy as a risk factor for hospitalization and death during influenza A (H1N1) pandemic in Paraguay

La influenza A (H1N1) se ha identificado como la causa de epidemia de Infección Respiratoria Aguda en Paraguay y en el mundo. Se analizaron los factores de riesgo asociados a la morbimortalidad en embarazadas con sospecha de infección por H1N1 notificadas a la Dirección General de Vigilancia de la Salud (DGVS) del MSPBS durante los primeros cuatro meses de la pandemia, en comparación con mujeres en edad fértil no embarazadas con sospecha de infección por H1N1. A partir del 28 de abril de 2009, la DGVS comenzó sistemáticamente la vigilancia de H1N1 en todas sus unidades notificadoras, siendo la notificación inmediata y por planilla individual basándose la notificación en la definición de casos confirmado establecidas por el país. Hasta el 25 de agosto del 2009 fueron notificadas 2268 mujeres con sospecha de H1N1, de las cuales 1120 tenían entre 15 a 40 años, y de ellas 117 estaban embarazadas. El 68% (79/117)de las embarazadas requirió hospitalización y la mortalidad fue de 21% (25/117), mientras que en grupo de las no embarazadas el 21% se hospitalizó (288 /1003) y la mortalidad fue de 1,5% (16/1003). Todos los casos fallecidos desarrollaron Infección Respiratoria Aguda Grave caracterizado por un síndrome de distrés respiratorio que en algunos casos requirieron asistencia respiratoria mecánica (ARM). Ninguna de las embarazadas refirió antecedente de co-morbilidad. El 22% (26/117) de las embarazadas y 2,9% (30/1003) de las no embarazadas recibieron Oseltamivir como tratamiento. Se evidencian que la infección produce alta morbimortalidad en embarazadas en comparación con mujeres del mismo grupo de edad, los cuales apoyan la recomendación de un tratamiento antiviral precoz en gestantes, así como un seguimiento clínico cercano.

Influenza A (H1N1) has been identified as the cause of the Acute Respiratory Infection epidemic in Paraguay and the world. Risk factors associated to morbid-mortality in cases of pregnant women with suspicion of H1N1 infection and notified to the General Direction of Health Surveillance (DGVS in Spanish) of the Ministry of Public Health and Social Welfare (MSPBS in Spanish) during the fourth first months of the pandemic were analyzed in comparison to non-pregnant fertile women with suspicion of H1N1 infection. From April28, 2009 the DGVS started a systematic surveillance of H1N1 in all its notifying units, being the notification immediate and by individual spreadsheet basing the notification inthe case definition established by the country. Until August 25, 2009 2,268 cases of women with suspicion of H1N1 were notified, 1,120 of them were between 15 to 40 years and from them 117 were pregnant. Sixty eight percent (79/117) of the pregnant women required hospitalization and mortality was 21% (25/117) while in the non-pregnant women, 21% were hospitalized (288 /1003) and mortality was 1.5% (16/1003). All deceased cases developed Serious Acute Respiratory Infection characterized by a respiratory distress syndrome that, in some cases, required mechanical respiratory assistance (MRA). None of the regnant women referred history of co-morbidity. Twenty two percent (26/117) of the pregnant women and 2.9% (30/1003) of the non-pregnant women received Oseltamivir as treatment. These results show that the infection produces high morbid-mortality in pregnant women in comparison to women of the same age group, supporting the recommendation of an early antiviral treatment in pregnant women as well as a close clinical follow-up.

Glial cell line-derived neurotrophic factor gene therapy ameliorates chronic hyperprolactinemia in senile rats.

Progressive dysfunction of hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons during normal aging is associated in the female rat with chronic hyperprolactinemia. We assessed the effectiveness of glial cell line-derived neurotrophic factor (GDNF) gene therapy to restore TIDA neuron function in senile female rats and reverse their chronic hyperprolactinemia. Young (2.5 months) and senile (29 months) rats received a bilateral intrahypothalamic injection (10(10) pfu) of either an adenoviral vector expressing the gene for beta-galactosidase; (Y-betagal and S-betagal, respectively) or a vector expressing rat GDNF (Y-GDNF and S-GDNF, respectively). Transgenic GDNF levels in supernatants of GDNF adenovector-transduced N2a neuronal cell cultures were 25+/-4 ng/ml, as determined by bioassay. In the rats, serum prolactin (PRL) was measured at regular intervals. On day 17 animals were sacrificed and neuronal nuclear antigen (NeuN) and tyrosine hydroxylase (TH) immunoreactive cells counted in the arcuate-periventricular hypothalamic region. The S-GDNF but not the S-betagal rats, showed a significant reduction in body weight. The chronic hyperprolactinemia of the senile females was significantly ameliorated in the S-GDNF rats (P<0.05) but not in the S-betagal rats. Neither age nor GDNF induced significant changes in the number of NeuN and TH neurons. We conclude that transgenic GDNF ameliorates chronic hyperprolactinemia in aging female rats, probably by restoring TIDA neuron function.

Multi-luminescent hybrid gadolinium oxide nanoparticles as potential cell labeling.

This manuscript analyses the use of newly developed hybrid gadolinium oxide nanoparticles as cell-labeling tracers. The nanoparticles are core-shell particles composed of a core of gadolinium oxide of [2-4] nm and a protecting shell of polysiloxane [1-3 nm] where different organic dyes (fluoresceine isothiocyanate (FITC) or rhodamine B isothiocyanate (RBITC)) are embedded. They are functionalized with poly(ethylene glycol)bis(carboxymethyl) to ensure their colloidal stability in biological buffers. These particles are potential multi-labeling tracers (magnetic and optical). In this paper, we show by optical imaging that they can be efficiently internalized in cells without cell alteration. The in-vitro uptake of the nanoparticles was followed in two cell lines (human fibroblasts and a human adenocarnima cell lines MCF7 cells). Nanoparticles distribution within cells was analysed by confocal analysis, and gadolinium concentration within cells was quantified by mass spectrometry (ICP-MS analysis). Nanoparticles uptake is found to be fast and efficient for both cell lines, with fluorescent labeling visible after 10 min of incubation whatever the nature of the fluorophore. The fluorescent intensity is mainly found as concentrated dots in the perinuclear region of the cells and decreases with the number of days in culture, but is still easily detectable after 3 days in culture. No significant effect on cell growth was detected. Finally, we show in this study the protective effect of the polysiloxane layer: encapsulation of RBITC within the polysiloxane shell, leads to a better photostability of this low cost dye than Cy3 and even reach a level comparable to Alexa 595. With their high photostability and long-lasting contrast properties, these hybrid luminescent nanoparticles appears thus as a versatile solution to assess multiple cell fate both in in-vitro cell model as well as in-vivo.

The ependymal route for insulin-like growth factor-1 gene therapy in the brain.

I.c.v. administration of the peptide insulin-like growth factor-1 (IGF-1) has been shown to be an effective neuroprotective strategy in the brain of different animal models, a major advantage being the achievement of high concentrations of IGF-1 in the brain without altering serum levels of the peptide. In order to exploit this therapeutic approach further, we used high performance recombinant adenoviral (RAd) vectors expressing their transgene under the control of the potent mouse cytomegalovirus immediate early (mCMV) promoter, to transduce brain ependymal cells with high efficiency and to achieve effective release of transgenic IGF-1 into the cerebrospinal fluid (CSF). We constructed RAd vectors expressing either a chimeric green fluorescent protein fused to HSV-1 thymidine kinase (TK/GFP)(fus), or the cDNA encoding rat IGF-1, both driven by the mCMV promoter. The vectors were injected into the lateral ventricles of young rats and chimeric GFP expression in brain sections was assessed by fluorescence microscopy. The ependymal cell marker vimentin was detected by immunofluorescence and nuclei were labeled with the DNA dye 4',6-diamidino-2-phenylindole. Blood and CSF samples were drawn at different times post-vector injection. In all cerebral ventricles, vimentin immunoreactive cells of the ependyma were predominantly transduced by RAd-(TK/GFP)(fus), showing nuclear and cytoplasmic expression of the transgene. For tanycytes (TK/GFP)(fus) expression was evident in their cytoplasmic processes as they penetrated deep into the hypothalamic parenchyma. I.c.v. injection of RAd-IGF-1 induced high levels of IGF-1 in the CSF but not in serum. We conclude that the ependymal route constitutes an effective approach for implementing experimental IGF-1 gene therapy in the brain.

Characterization of an acquired dps-containing gene island in the lactic acid bacterium Oenococcus oeni.

AIMS: To identify novel actors responsible for the marked adaptation of the Oenococcus oeni species to its environment. METHODS AND RESULTS: Genomic surveillance of the available genome sequences from O. oeni indicated the presence of a small ORF, encoding a protein named Dps(A). The cloned gene complemented the dps(-) mutant of Escherichia coli and conferred resistance to hydrogen peroxide, wine, and metals. The dps(A) gene was flanked by IS-related elements. The entire region was characterized by an anomalously high GC content compared to those reported for oenococcal genomes. The dps(A) gene was present in 15 of the 38 tested isolates. Positive strains originated from different geographical areas and sources. No change in tolerance to wine or to oxidative stress was observed between O. oeni strains harbouring dps(A) and those not harbouring this gene. CONCLUSIONS: Some O. oeni have acquired a functional homologue to the dps gene from E. coli as part of a mobile element. SIGNIFICANCE AND IMPACT OF THE STUDY: Dps(A) probably increases the bacterial fitness in response to environmental challenges. However, the physiological condition under which it adds a selective advantage to O. oeni during winemaking remains to be found.

Gene therapy in the neuroendocrine system.

The implementation of experimental gene therapy in animal models of neuroendocrine diseases is an area of growing interest. In the hypothalamus, restorative gene therapy has been successfully implemented in Brattleboro rats, an arginine vasopressin (AVP) mutant which suffers from diabetes insipidus, and in Koletsky (fa(k)/fa(k)) and in Zucker (fa/fa) rats which have leptin receptor mutations that render them obese, hyperphagic and hyperinsulinemic. In the above models, viral vectors expressing AVP, leptin receptor b and proopiomelanocortin, respectively, were stereotaxically injected in the relevant hypothalamic regions. In rats, aging brings about a progressive degeneration and loss of hypothalamic tuberoinfundibular dopaminergic (TIDA) neurons, which are involved in the tonic inhibitory control of prolactin secretion and lactotropic cell proliferation. Stereotaxic injection of an adenoviral vector expressing insulin-like growth factor I corrected their chronic hyperprolactinemia and restored TIDA neuron numbers. Spontaneous intermediate lobe pituitary tumors in a retinoblastoma (Rb) gene mutant mouse were corrected by injection of an adenoviral vector expressing the human Rb cDNA and experimental prolactinomas in rats were partially reduced by intrapituitary injection of an adenoviral vector expressing the HSV1-thymidine kinase suicide gene. These results suggest that further implementation of gene therapy strategies in neuroendocrine models may be highly rewarding.

Developmental toxicity of combined ethylbenzene and methylethylketone administered by inhalation to rats.

Pregnant Sprague-Dawley rats were exposed to ethylbenzene (EB; 0, 250, or 1000 ppm) and methylethylketone (MEK; 0, 1000, or 3000 ppm), alone and in combination, by inhalation, for 6h/day, during days 6-20 of gestation. Maternal toxicity, evidenced by decreased in body weight gain and food consumption, tended to be greater after simultaneous exposures to the high concentrations of 1000 ppm EB and 3000 ppm MEK, when compared to the treatments with individual compounds. No significant increase in embryo/fetal lethality or incidence of malformations and variations was observed in any of the treatment groups. Fetal body weight was significantly reduced after individual treatment with 1000 ppm EB or 3000 ppm MEK, and in the combined groups. There was no evidence of interaction between EB and MEK in causing developmental toxicity.

Combined effects of noise and styrene on hearing: comparison between active and sedentary rats.

In this study, two investigations were carried out with adult Long-Evans rats exposed to increasing concentrations of styrene. In the first experiment, the hearing of rats, which were forced to walk in a special wheel during the exposure, was compared to that of rats which were sleepy in their cage. The active rats were exposed to styrene concentrations ranging from 300 to 600 ppm, whereas the sedentary rats were exposed from 500 to 1000 ppm for 4 weeks, 5 days per week, 6 hours per day. In the second experiment, designed to evaluate the hearing risks at threshold limit values, active rats were exposed either to a noise having a Leq8h of 85 dB (equivalent level of a continuous noise for a typical 8-h workday), or to 400-ppm styrene or to a simultaneous exposure to noise and styrene. In both experiments, auditory function was tested by auditory-evoked potentials from the inferior colliculus and completed by morphological analyses of the organ of Corti. The results of the first experiment showed that the same amount of styrene-induced hearing loss can be obtained by using concentrations approximately 200 ppm lower in active rats than in sedentary rats. The second investigation showed that, in spite of the low-intensity noise and the low-concentration of styrene, there is a clear risk of potentiation of styrene-induced hearing loss by noise. These findings and exposure conditions were discussed and extrapolated with regard to the risk assessment for human beings. The authors propose to decrease the French threshold limit value of styrene for ensuring a high level of protection for human hearing.

Cellular distribution of growth hormone-releasing hormone receptor in human reproductive system and breast and prostate cancers.

Growth hormone releasing hormone receptor (GHRH-R) mRNA and protein was first localized to the anterior pituitary gland, consequent with the action of its ligand on GH synthesis and release. Subsequent studies found GHRH-R also expressed in the hypothalamus and in systemic tissues including those of the reproductive system. In the present work, we studied the distribution of GHRH-R in human reproductive system of males and females by immunohistochemical method. GHRH-R immunostaining was localized in male reproductive system: Leydig cells, Sertoli and basal germ cells of the seminiferous tubules and prostate secretory cells. GHRH-R immunostaining was also demonstrated in the ovary: oocytes, follicular cells, granulosa, thecal and corpus luteum cells. Endometrial glands, placenta and normal mammary glands also showed GHRH-R immunostaining. Our results demonstrate the localization of GHRH-R in the reproductive system, which may mediate the direct action of GHRH in these tissues. Moreover, GHRH-R was demonstrated in prostate and breast carcinomas, opening a variety of possibilities for the use of GHRH antagonists in the treatment of prostatic and mammary tumors.

Developmental toxicity of two trimethylbenzene isomers, mesitylene and pseudocumene, in rats following inhalation exposure.

The developmental toxicity of two trimethylbenzene isomers, mesitylene (1,3,5-trimethylbenzene) and pseudocumene (1,2,4-trimethylbenzene) was studied in Sprague-Dawley rats following inhalation exposure. Pregnant rats were exposed whole body to vapours of mesitylene (0, 100, 300, 600, and 1200 ppm) or pseudocumene (0, 100, 300, 600, and 900 ppm), 6h/day, on gestational days (GD) 6 through 20. Significant decrease in maternal body weight gain and food consumption was observed at concentrations of 300 ppm mesitylene, 600 ppm pseudocumene, or greater. Fetal toxicity, expressed as significant reduction in fetal body weight, occurred at 600 and 1200 ppm mesitylene, and at 600 and 900 ppm pseudocumene. There was no evidence of embryolethal or teratogenic effects following inhalation exposure to either of these chemicals. In summary, the no-observed-adverse-effect-level (NOAEL) for maternal toxicity was 100 ppm for mesitylene and 300 ppm for pseudocumene, and the NOAEL for developmental toxicity was 300 ppm for mesitylene and pseudocumene.

Critical period for styrene ototoxicity in the rat.

The current experiments were undertaken to determine whether or not styrene-induced hearing loss in the rat depends more on the existence of a critical period between 14 and 21 weeks of age than on body weight. For these purposes, two experiments were carried out with mature Long-Evans rats. In the first experiment, two groups of 5-month old rats, but having different body weight (slim: 314 g vs. fat: 415 g) were exposed to 700 ppm styrene for 4 consecutive weeks, 5 days per week, 6 hours per day. In the second experiment, two groups of rats having the same weight: 345 g, but different ages (14- vs. 21- week old) were exposed to styrene in strictly identical experimental conditions. Auditory sensitivity was tested by recording evoked potentials from the inferior colliculus. Surface preparations of the organ of Corti were also performed to complete the investigation. At the end of the six week recovery period following the styrene exposure, a 7 dB permanent threshold shift (PTS) was obtained with the same age animals regardless of the body weight. Consequently, weight was not a major factor in styrene-induced hearing loss. Age was a more critical factor in determining higher sensitivity to styrene. Indeed, the three months old group had 23.5 dB PTS, whereas the five months old group had only a 7.7 dB PTS at 16 kHz. Thus, a 15 dB difference of PTS was obtained between the rats having the same weight but different age. While the weight does not play a major role in styrene ototoxicity, there is a critical period whose duration lasts more than three months and for which the susceptibility to styrene is enhanced.

Suppressor of cytokine signalling gene expression is elevated in breast carcinoma.

Cytokines are important for breast cell function, both as trophic hormones and as mediators of host defense mechanisms against breast cancer. Recently, inducible feedback suppressors of cytokine signalling (SOCS/JAB/SSI) have been identified, which decrease cell sensitivity to cytokines. We examined the expression of SOCS genes in 17 breast carcinomas and 10 breast cancer lines, in comparison with normal tissue and breast lines. We report elevated expression of SOCS-1-3 and CIS immunoreactive proteins within in situ ductal carcinomas and infiltrating ductal carcinomas relative to normal breast tissue. Significantly increased expression of SOCS-1-3 and CIS transcripts was also shown by quantitative in situ hybridisation within both tumour tissue and reactive stroma. CIS transcript expression was elevated in all 10 cancer lines, but not in control lines. However, there was no consistent elevation of other SOCS transcripts. CIS protein was shown by immunoblot to be present in all cancer lines at increased levels, mainly as the 47 kDa ubiquitinylated form. A potential proliferative role for CIS overexpression is supported by reports that CIS activates ERK kinases, and by strong induction in transient reporter assays with an ERK-responsive promoter. The in vivo elevation of SOCS gene expression may be part of the host/tumour response or a response to autocrine/paracrine GH and prolactin. However, increased CIS expression in breast cancer lines appears to be a specific lesion, and could simultaneously shut down STAT 5 signalling by trophic hormones, confer resistance to host cytokines and increase proliferation through ERK kinases.