Synthesis of aminopyrazoles from sydnones and ynamides.

Aminopyrazoles are prepared from readily accessible sydnones and sulfonyl ynamides using either a copper-mediated sydnone alkyne cycloaddition (CuSAC) or in situ generated strained cyclic ynamides.

Endogenous jasmonic and salicylic acids levels in the Cd-hyperaccumulator Noccaea (Thlaspi) praecox exposed to fungal infection and/or mechanical stress.

KEY MESSAGE: Sensitivity to Erysiphe in Noccaea praecox with low metal supply is related to the failure in enhancing SA. Cadmium protects against fungal-infection by direct toxicity and/or enhanced fungal-induced JA signaling. Metal-based defense against biotic stress is an attractive hypothesis on evolutionary advantages of plant metal hyperaccumulation. Metals may compensate for a defect in biotic stress signaling in hyperaccumulators (metal-therapy) by either or both direct toxicity to pathogens and by metal-induced alternative signaling pathways. Jasmonic acid (JA) and salicylic acid (SA) are well-established components of stress signaling pathways. However, few studies evaluate the influence of metals on endogenous concentrations of these defense-related hormones. Even less data are available for metal hyperaccumulators. To further test the metal-therapy hypothesis we analyzed endogenous SA and JA concentrations in Noccaea praecox, a cadmium (Cd) hyperaccumulator. Plants treated or not with Cd, were exposed to mechanical wounding, expected to enhance JA signaling, and/or to infection by biotrophic fungus Erysiphe cruciferarum for triggering SA. JA and SA were analyzed in leaf extracts using LC-ESI(-)-MS/MS. Plants without Cd were more susceptible to fungal attack than plants receiving Cd. Cadmium alone tended to increase leaf SA but not JA. Either or both fungal attack and mechanical wounding decreased SA levels and enhanced JA in the Cd-rich leaves of plants exposed to Cd. High leaf Cd in N. praecox seems to hamper biotic-stress-induced SA, while triggering JA signaling in response to fungal attack and wounding. To the best of our knowledge, this is the first report on the endogenous JA and SA levels in a Cd-hyperaccumulator exposed to different biotic and abiotic stresses. Our results support the view of a defect in SA stress signaling in Cd hyperaccumulating N. praecox.

Correlation between CTG trinucleotide repeat length and frequency of severe congenital myotonic dystrophy.

The myotonic dystrophy (DM) mutation has recently been identified as an unstable trinucleotide CTG repeat which is present 5-30 times in the normal population but which is amplified up to 2,000 times in DM. We have determined the status of the CTG repeat in 272 DM individuals. Infants with severe congenital DM, as well as their mothers, are shown to have on average a greater amplification of the CTG repeat than is seen in the noncongenital DM population. This fact, when viewed in conjunction with the tendency to increased CTG repeat length in our DM kindreds, provides evidence for the existence of genetic anticipation in the transmission of DM.

Docetaxel combined with irinotecan or 5-fluorouracil in patients with advanced oesophago-gastric cancer: a randomised phase II study.

BACKGROUND: Docetaxel and irinotecan chemotherapy have shown good efficacy in the treatment of advanced oesophago-gastric cancer. This randomised phase II study evaluated the efficacy and toxicity profile of two non-platinum docetaxel-based doublet regimens in advanced oesophago-gastric cancer. METHODS: Chemotherapy-naïve patients with advanced oesophago-gastric cancer were randomised to receive either 3-weekly DI (docetaxel 60 mg m(-2) plus irinotecan 250 mg m(-2) (Day 1)) or 3-weekly DF (docetaxel 85 mg m(-2) (Day 1) followed by 5-fluorouracil 750 mg m(-2) per day as a continuous infusion (Days 1-5)). RESULTS: A total of 85 patients received DI (n=42) or DF (n=43). The primary endpoint was overall response rate (ORR). The ORR and time to progression (TTP) in the evaluable population (n=65) were 37.5% (DI) vs 33.3% (DF), and 4.2 months vs 4.4 months, respectively. In the intent-to-treat population, the observed ORR, TTP and median overall survival were similar between the two groups. Grade 3-4 neutropenia, febrile neutropenia and diarrhoea were more frequent in the DI arm as compared with the DF arm (83.3% vs 69.8%, 40.5% vs 18.6%, and 42.9% vs 16.3%, respectively). CONCLUSION: Both docetaxel-based doublet regimens show comparable efficacy; however, the DF regimen was associated with a better toxicity profile and is an alternative treatment option for patients in whom platinum-based regimens are unsuitable.

[Applications of diffusion techniques in magnetic resonance imaging of musculoskeletal tumors]. / Aplicaciones de la técnica de difusión por resonancia magnética en el manejo de la patología tumoral osteomuscular.

Magnetic resonance imaging (MRI) is the technique of choice in the diagnosis, staging, and follow-up of musculoskeletal tumors. Diffusion imaging is a new functional MRI technique that provides information that is complementary to that obtained in conventional MRI sequences. Diffusion imaging has proven useful in different clinical situations like the characterization of disease involving the bone marrow (bone metastases, benign fractures, or hematological disease), the evaluation of tumors of the bones and soft tissues, and the monitoring of the response to treatment in patients with tumors. The aim of this article is to review the diffusion technique in MRI and its current clinical applications in the management of musculoskeletal tumors.

Efficiency and sensitivity optimization of a protocol to quantify indoor airborne SARS-CoV-2 levels.

BACKGROUND: Development of methodologies to quantify airborne micro-organisms is needed for the prevention and control of infections. It is difficult to conclude which is the most efficient and sensitive strategy to assess airborne SARS-CoV-2 RNA levels due to the disparity of results reported in clinical settings. AIM: To improve our previously reported protocol of measuring SARS-CoV-2 RNA levels, which was based on bioaerosol collection with a liquid impinger and RNA quantification with droplet digital polymerase chain reaction (ddPCR). METHODS: Air samples were collected in COVID-19 patient rooms to assess efficiency and/or sensitivity of different air samplers, liquid collection media, and reverse transcriptases (RT). FINDINGS: Mineral oil retains airborne RNA better than does hydrophilic media without impairing integrity. SARS-CoV-2 ORF1ab target was detected in 80% of the air samples using BioSampler with mineral oil. No significant differences in effectiveness were obtained with MD8 sampler equipped with gelatine membrane filters, but the SARS-CoV-2 copies/m3 air obtained with the latter were lower (28.4 ± 6.1 vs 9 ± 1.7). SuperScript II RT allows the detection of a single SARS-CoV-2 genome RNA molecule by ddPCR with high efficiency. This was the only RT that allowed the detection of SARS-CoV-2 N1 target in air samples. CONCLUSION: The collection efficiency and detection sensivity of a protocol to quantify SARS-CoV-2 RNA levels in indoor air has been improved in the present study. Such optimization is important to improve our understanding of the microbiological safety of indoor air.

[Moyamoya disease: revision and description of a number of pedriatic cases]. / Enfermedad de moyamoya: descripción de una serie de casos pediátricos.

INTRODUCTION: Moyamoya disease is caused because of progressive occlusion of the arterial circle of Willis, leading to a compensatory net-like abnormal vessels development. The objective is to describe the number of cases in our center (tertiary hospital). PATIENTS AND METHODS: Retrospective study. Revision of pediatric medical histories diagnosed of moyamoya disease or moyamoya syndrome (in case of predisposing disease) between 2005 and 2018. Demographic variables were collected, related to diagnosis, risk factors, treatment, and follow-up. RESULTS: Seven cases were collected with a median age of 6 years and an equitable distribution by sex. Five associated predisposing pathologies (Down syndrome, neurofibromatosis, sickle cell disease, Behcet). The main clinical diagnosis was neurological focus (five cases), followed by epileptic seizures (four), and headache (two). One was asymptomatic at diagnosis. Six strokes were documented, five of them were isquemic. The arteriography (goldstardard) was made in five patients. Five presented bilateral involvement of the vessels, the internal carotid arteries and the middle cerebral arteries were the most affected. Six received acetylsalicylic acid treatment and five of them required antiepileptic drugs. Revascularization surgery (encephaloduroarteriomyosinangiosis) was performed in four patients, and in one, strokes persisted. The most prevalent sequelae were hemiparesis and psychomotor retardation. CONCLUSIONS: The risk factors presented in our patients match to those described in the literature. The symptoms at the onset can be diverse and ischemic strokes predominate in our series. Revascularization surgery was effective in more than half of the cases. Subsequent follow-up is necessary to assess complications and sequelae.

TITLE: Enfermedad de moyamoya: descripción de una serie de casos pediátricos.Introducción. La enfermedad de moyamoya se produce por la oclusión de las arterias alrededor del polígono de Willis y genera una amplia red de vasos colaterales. El objetivo es describir la serie histórica de nuestro centro (hospital terciario). Pacientes y métodos. Es un estudio retrospectivo. Se hizo una revisión de historias clínicas de pacientes pediátricos diagnosticados de enfermedad o síndrome de moyamoya (si patología predisponente) entre 2005 y 2018. Se recogieron variables demográficas, relacionadas con el diagnóstico, factores de riesgo, tratamiento y seguimiento. Resultados. Se obtuvieron siete casos, con una mediana de edad de seis años y distribución por sexos equitativa. Cinco asociaban patologías predisponentes (síndrome de Down, neurofibromatosis, drepanocitosis y Behçet). La clínica predominante en el diagnóstico fue focalidad neurológica (cinco casos), seguida de crisis epilépticas (cuatro) y cefalea (dos). Un paciente era asintomático en el momento del diagnóstico. Se documentaron seis ictus, cinco de los cuales fueron isquémicos. La arteriografía (técnica de referencia) constaba en cinco pacientes. Cinco presentaban afectación bilateral y estaban mayormente afectadas las arterias carótidas internas y las cerebrales medias. Seis recibieron tratamiento con ácido acetilsalicílico y cinco necesitaron fármacos antiepilépticos. La cirugía de revascularización (encefaloduroarteriomiosinangiosis) se realizó en cuatro pacientes y en uno persistieron los ictus. Las secuelas más prevalentes fueron hemiparesia y retraso psicomotor. Conclusiones. Los factores de riesgo presentados en nuestros pacientes se ajustan a los descritos en la bibliografía. La clínica en el inicio puede ser diversa y predominan los ictus isquémicos en nuestra serie. La cirugía de revascularización fue efectiva en más de la mitad de los casos. Es necesario un seguimiento posterior para evaluar complicaciones y secuelas.

CD50 (intercellular adhesion molecule 3) stimulation induces calcium mobilization and tyrosine phosphorylation through p59fyn and p56lck in Jurkat T cell line.

The leukocyte differentiation antigen, CD50, has been recently identified as the intercellular adhesion molecule 3 (ICAM-3), the third counter-receptor of leukocyte function-associated antigen 1 (LFA-1). This molecule seems to be specially involved in the adhesion events of the initial phases of the immune response. To characterize the role of CD50 in leukocyte interactions, the different molecular events induced after cross-linking of CD50 on T cell-derived Jurkat cell line have been analyzed. When cells were incubated with anti-CD50 mAbs and cross-linked with polyclonal goat anti-mouse immunoglobulins, a rise in intracellular calcium concentration ([Ca2+]i) was observed. This increase in [Ca2+]i was mainly due to the uptake of extracellular Ca2+. This Ca2+ flux involved tyrosine phosphorylations and was further increased by CD3 costimulation. These data, together with those obtained by phosphotyrosine (P-Tyr) immunoprecipitation and in vitro kinase assays, suggested the involvement of protein-tyrosine kinases (PTK) in CD50 transduction pathways. By using specific antisera, the presence of p56lck and p59fyn protein tyrosine kinases (PTK) was clearly demonstrated in the CD50 immunoprecipitates. These findings suggest that the interaction of CD50 with its natural ligand (LFA-1) may result in T lymphocyte activation events, in which CD50 could play a very active role after antigen triggering.

[Usefulness of magnetic resonance imaging in prostate cancer]. / Utilidad de la resonancia magnética en el cáncer de próstata.

In the last decade, technical advances in magnetic resonance imaging (MRI) have made it the technique of choice in the overall management of patients with suspected or confirmed prostate cancer. MR makes it possible to acquire information about morphology and function in the same examination by using techniques like spectroscopy, diffusion, and dynamic sequences with intravenous contrast material administration. Moreover, MRI enables both focused study of the prostate gland and of regional and/or whole-body involvement, depending on the clinical indications, in less than an hour. The main clinical indications for MRI of the prostate are a) staging local, regional, and/or remote disease; b) detecting prostate cancer or guiding prostate biopsy in cases of clinical suspicion or negative findings in previous biopsy specimens; and c) monitoring the response to treatment. It is important to know the different protocols with specific MRI sequences for the prostate, depending on the different clinical indications, to ensure that they are performed and interpreted correctly. This article provides up-to-date information about the use of MRI for the study of the prostate to show how the morphological and functional information can be used in clinical practice.

Reduction in size of the myotonic dystrophy trinucleotide repeat mutation during transmission.

Myotonic dystrophy (DM) is an autosomal-dominant disorder that affects 1 in 8000 individuals. Amplification of an unstable trinucleotide CTG repeat, located within the 3' untranslated region of a gene, correlates with a more severe DM phenotype. In three cases, the number of CTG repeats was reduced during the transmission of the DM allele; in one of these cases, the number was reduced to within the normal range and correlated at least with a delay in the onset of clinical signs of DM. Haplotype data of six polymorphic markers in the DM gene region indicate that, in this latter case, two stretches of the affected chromosome had been exchanged with that region of the wild-type chromosome.

Myotonic dystrophy mutation: an unstable CTG repeat in the 3' untranslated region of the gene.

Myotonic dystrophy (DM) is the most common inherited neuromuscular disease in adults, with a global incidence of 1 in 8000 individuals. DM is an autosomal dominant, multisystemic disorder characterized primarily by myotonia and progressive muscle weakness. Genomic and complementary DNA probes that map to a 10-kilobase Eco RI genomic fragment from human chromosome 19q13.3 have been used to detect a variable length polymorphism in individuals with DM. Increases in the size of the allele in patients with DM are now shown to be due to an increased number of trinucleotide CTG repeats in the 3' untranslated region of a DM candidate gene. An increase in the severity of the disease in successive generations (genetic anticipation) is accompanied by an increase in the number of trinucleotide repeats. Nearly all cases of DM (98 percent or 253 of 258 individuals) displayed expansion of the CTG repeat region. These results suggest that DM is primarily caused by mutations that generate an amplification of a specific CTG repeat.

Transfer of selected mineral nutrients and trace elements in the host-hemiparasite association, Cistus-Odontites lutea, growing on and off metal-polluted sites.

The role of a hemiparasitic life-style in plant resistance to toxic trace elements in polluted soils is unclear. Restriction of metal uptake by the host, restriction of metal transfer from host to parasite, or transformation of metals into a less toxic form may play a role. This study analysed the transfer of selected mineral elements from soil to host (Cistus spp.) and from host to hemiparasite (Odontites lutea) at locations with different metal burdens: a Cu-rich serpentine site, Pb-Ba mine spoil and an unpolluted soil. Highest soil-to-host transfer factors for K, Mg, Ca, Zn, Cu and Pb were observed on the unpolluted soil. Statistically significant differences among locations of host-to-parasite transfer factors were only found for Ca and Pb. Restriction of transfer of unfavourable Ca/Mg ratios, characteristic at the serpentine site, and of high Pb and Zn concentrations at the Pb-Ba mine occurred mainly at the soil-host, and not at the host-parasite, level. Odontites lutea was able to withstand enhanced Zn and Pb concentrations and low Fe/Cu ratios in shoot tissue without developing toxicity symptoms. This could be caused by specific metal resistance mechanisms in this hemiparasite and/or the transformation and transfer of these metals into a less toxic form by the metal-tolerant host.

Effect of single-nucleotide polymorphisms of the 5' untranslated region of the human α-galactosidase gene on enzyme activity, and their frequencies in Portuguese caucasians.

BACKGROUND: The α-galactosidase gene (GLA) has three single-nucleotide polymorphisms in the 5' untranslated region of exon 1, respectively g.1150G>A, g.1168G>A, g.1170C>T. The g.1150A allele is associated with increased plasma α-galactosidase (α-Gal) activity in hemizygotes, while the others are regarded as biologically neutral. The primary goal of this investigation was to test the hypothesis, raised by a clinical observation and results of a family study, that the g.1170T allele polymorphism is associated with lower α-Gal expression. SUBJECTS AND METHODS: Plasma and leukocyte α-Gal activities were assayed in unrelated healthy young adults of both sexes, who had been genotyped for GLA exon 1, and enzyme activity values in carriers of any of the polymorphisms were compared to those of individuals with the standard genotype; GLA exon 1 was genotyped in males who had α-Gal activity in dried blood spots lower than 2 SD below the cohort average. RESULTS AND CONCLUSIONS: Mean α-Gal leukocyte activity was ∼ 25% higher in subjects with the g.1170C or CC genotype than in those with the alternative genotypes (p < 0.05). The frequency of the g.1170T allele in subjects with low α-Gal activity in dried blood spots was 4-fold higher (p < 0.05) than in the general population. As in hemizygotes, the g.1150A heterozygote identified in this study had plasma α-Gal activity more than 2-fold above the normal mean. The g.1168A allele did not affect enzyme activity. Surprisingly, females with the standard GLA exon 1 genotype had significantly higher plasma α-Gal activity than genetically comparable males.

The effect of silicon on the symptoms of manganese toxicity in maize plants.

The effect of exogenously applied silicon (Si) on plant growth, lipid peroxidation, total phenolic compounds and non-protein thiols was studied in two maize varieties (Zea mays L. vars. Kneja 605, 434) differing in sensitivity to excess manganese (Mn). Based on the density of brown spots per leaf area and relative shoot weight (RSW) used to define Mn tolerance var. Kneja 434 was found to be more Mn-tolerant than Kneja 605. The lipid peroxidation level and total phenolic compounds were enhanced with increasing Mn concentration in the nutrient solution. In addition, the Mn-sensitive var. Kneja 605 with markedly expressed first visible Mn toxicity symptoms had higher levels of total phenolic acids than var. Kneja 434 thus supporting the hypothesis that a stimulating effect of Mn on phenol content reflected rather a stress response to Mn excess than a tolerance mechanism. In contrast, non-protein SH content increased to a higher extent in the Mn-tolerant var. Kneja 434. The increased amount of non-protein SH compounds was accompanied by a much stronger oxidative stress in the Mn-sensitive plants when compared with the Mn-tolerant variety, thus suggesting that non-protein SH compounds may play a role in Mn tolerance in maize. The addition of silicon (Si) reduced the density of brown spots per leaf area as well as lipid peroxidation level and improved plant growth in Mn-treated plants.

Role of FK778 alone or in combination with tacrolimus or mTOR inhibitors as an immunomodulator of immunofunctions: in vitro evaluation of T cell proliferation and the expression of lymphocyte surface antigens.

We evaluated the in vitro capacity of FK778, alone or in combination with other immunosuppressive drugs: Tacrolimus (TRL); Sirolimus (SRL), Everolimus (EVL), to inhibit clonal expansion of T-lymphocytes and expression of lymphocyte-activation surface antigens; secondly, we compared the immunosuppressive potential of FK778 combined with TRL, SRL and EVL with the same combinations using Mycophenolic acid (MPA) as antimetabolite. Lymphocyte proliferation was assessed by 3H-Thymidine incorporation, in whole blood cultures stimulated with ConA. The effect of FK778 on alloresponse was evaluated by MLC and the expression of lymphocyte surface antigens by cytometry. FK778, TRL, SRL and EVL showed a high in vitro capacity to inhibit lymphocyte proliferation in a concentration-dependent way. Combinations of FK778 with TRL, SRL, or EVL presented an additive effect, especially FK778+TRL. Similar inhibition capacity of the clonal expansion was observed, when FK778 was combined with TRL, SRL or EVL, respecting the same combinations but using MPA instead of FK778. In addition, FK778 inhibited the expression of lymphocyte surface antigens involved in activation, co-stimulatory and apoptosis signals. In conclusion, FK778 inhibits the proliferative response induced by mitogeneic and allogeneic stimuli and the expression of surface antigens. Combinations of FK778 with TRL or mTOR inhibitors presented an additive effect and their action on T cell proliferation was similar to that of combinations with MPA. Since FK778, TRL and mTOR inhibitors present different action mechanisms and involve different cellular targets, these combinations may help prevent episodes of allorejection in organ transplants. FK778 and mTOR inhibitors may represent an alternative treatment for patients with renal failure.

Enfermedad de moyamoya: descripción de una serie de casos pediátricos / Moyamoya disease: revision and description of a number of pedriatic cases

Introducción: La enfermedad de moyamoya se produce por la oclusión de las arterias alrededor del polígono de Willis y genera una amplia red de vasos colaterales. El objetivo es describir la serie histórica de nuestro centro (hospital terciario). Pacientes y métodos: Es un estudio retrospectivo. Se hizo una revisión de historias clínicas de pacientes pediátricos diagnosticados de enfermedad o síndrome de moyamoya (si patología predisponente) entre 2005 y 2018. Se recogieron variables demográficas, relacionadas con el diagnóstico, factores de riesgo, tratamiento y seguimiento. Resultados: Se obtuvieron siete casos, con una mediana de edad de seis años y distribución por sexos equitativa. Cinco asociaban patologías predisponentes (síndrome de Down, neurofibromatosis, drepanocitosis y Behçet). La clínica predominante en el diagnóstico fue focalidad neurológica (cinco casos), seguida de crisis epilépticas (cuatro) y cefalea (dos). Un paciente era asintomático en el momento del diagnóstico. Se documentaron seis ictus, cinco de los cuales fueron isquémicos. La arteriografía (técnica de referencia) constaba en cinco pacientes. Cinco presentaban afectación bilateral y estaban mayormente afectadas las arterias carótidas internas y las cerebrales medias. Seis recibieron tratamiento con ácido acetilsalicílico y cinco necesitaron fármacos antiepilépticos. La cirugía de revascularización (encefaloduroarteriomiosinangiosis) se realizó en cuatro pacientes y en uno persistieron los ictus. Las secuelas más prevalentes fueron hemiparesia y retraso psicomotor. Conclusiones: Los factores de riesgo presentados en nuestros pacientes se ajustan a los descritos en la bibliografía. La clínica en el inicio puede ser diversa y predominan los ictus isquémicos en nuestra serie. La cirugía de revascularización fue efectiva en más de la mitad de los casos. Es necesario un seguimiento posterior para evaluar complicaciones y secuelas.(AU)

Introduction: Moyamoya disease is caused because of progressive occlusion of the arterial circle of Willis, leading to a compensatory net-like abnormal vessels development. The objective is to describe the number of cases in our center (tertiary hospital). Patients and methods: Retrospective study. Revision of pediatric medical histories diagnosed of moyamoya disease or moyamoya syndrome (in case of predisposing disease) between 2005 and 2018. Demographic variables were collected, related to diagnosis, risk factors, treatment, and follow-up. Results: Seven cases were collected with a median age of 6 years and an equitable distribution by sex. Five associated predisposing pathologies (Down syndrome, neurofibromatosis, sickle cell disease, Behçet). The main clinical diagnosis was neurological focus (five cases), followed by epileptic seizures (four), and headache (two). One was asymptomatic at diagnosis. Six strokes were documented, five of them were isquemic. The arteriography (goldstardard) was made in five patients. Five presented bilateral involvement of the vessels, the internal carotid arteries and the middle cerebral arteries were the most affected. Six received acetylsalicylic acid treatment and five of them required antiepileptic drugs. Revascularization surgery (encephaloduroarteriomyosinangiosis) was performed in four patients, and in one, strokes persisted. The most prevalent sequelae were hemiparesis and psychomotor retardation. Conclusions: The risk factors presented in our patients match to those described in the literature. The symptoms at the onset can be diverse and ischemic strokes predominate in our series. Revascularization surgery was effective in more than half of the cases. Subsequent follow-up is necessary to assess complications and sequelae.(AU)

Water Transport Properties of Roots and Root Cortical Cells in Proton- and Al-Stressed Maize Varieties.

Root and root cell pressure-probe techniques were used to investigate the possible relationship between Al- or H+-induced alterations of the hydraulic conductivity of root cells (LPc) and whole-root water conductivity (LPr) in maize (Zea mays L.) plants. To distinguish between H+ and Al effects two varieties that differ in H+ and Al tolerance were assayed. Based on root elongation rates after 24 h in nutrient solution of pH 6.0, pH 4.5, or pH 4.5 plus 50 [mu]M Al, the variety Adour 250 was found to be H+-sensitive and Al-tolerant, whereas the variety BR 201 F was found to be H+-tolerant but Al-sensitive. No Al-induced decrease of root pressure and root cell turgor was observed in Al-sensitive BR 201 F, indicating that Al toxicity did not cause a general breakdown of membrane integrity and that ion pumping to the stele was maintained. Al reduced LPc more than LPr in Al-sensitive BR 201 F. Proton toxicity in Adour 250 affected LPr more than LPc. In this Al-tolerant variety LPc was increased by Al. Nevertheless, this positive effect on LPc did not render higher LPr values. In conclusion, there were no direct relationships between Al- or H+-induced decreases of LPr and the effects on LPc. To our knowledge, this is the first time that the influence of H+ and Al on root and root cell water relations has been directly measured by pressure-probe techniques.

Change in apoplastic aluminum during the initial growth response to aluminum by roots of a tolerant maize variety

Root elongation, hematoxylin staining, and changes in the ultrastructure of root-tip cells of an Al-tolerant maize variety (Zea mays L. C 525 M) exposed to nutrient solutions with 20 &mgr;M Al (2.1 &mgr;M Al3+ activity) for 0, 4, and 24 h were investigated in relation to the subcellular distribution of Al using scanning transmission electron microscopy and energy-dispersive x-ray microanalysis on samples fixed by different methods. Inhibition of root-elongation rates, hematoxylin staining, cell wall thickening, and disturbance of the distribution of pyroantimoniate-stainable cations, mainly Ca, was observed only after 4 and not after 24 h of exposure to Al. The occurrence of these transient, toxic Al effects on root elongation and in cell walls was accompanied by the presence of solid Al-P deposits in the walls. Whereas no Al was detectable in cell walls after 24 h, an increase of vacuolar Al was observed after 4 h of exposure. After 24 h, a higher amount of electron-dense deposits containing Al and P or Si was observed in the vacuoles. These results indicate that in this tropical maize variety, tolerance mechanisms that cause a change in apoplastic Al must be active. Our data support the hypothesis that in Al-tolerant plants, Al can rapidly cross the plasma membrane; these data clearly contradict the former conclusions that Al mainly accumulates in the apoplast and enters the symplast only after severe cell damage has occurred.

Immunological benefits of antiretroviral therapy in very early stages of asymptomatic chronic HIV-1 infection.

OBJECTIVES: To assess whether an almost complete restoration of immune system can be achieved when antiretroviral therapy is initiated at very early stages of asymptomatic chronic HIV-1 infection. DESIGN: T cell subsets and cell-mediated responses were analysed at baseline and after 12 months of either a double or a triple antiretroviral therapy in 26 asymptomatic HIV-1-infected patients with CD4 T cell counts > 500 x 10(6) cells/l and a baseline plasma viral load > 10000 copies/ml. RESULTS: Triple therapy was significantly more effective in reducing plasma HIV RNA to undetectable levels, in returning CD4:CD8 ratio to nearly normal levels, in reducing activated cells (CD38) and in increasing naive (CD45RA+CD45RO-) and memory (CD45RA-CD45RO+) CD4 cells. Both double and triple therapies caused a clear decrease in memory (CD45RA-CD45RO+) CD8 cells as well as a significant increase in the CD28 subset of CD8 cells. At baseline, there was an important increase in cells producing interferon-gamma (IFNgamma) with no significant abnormalities in T lymphocytes producing interleukin 2 (IL-2), tumour necrosis factor alpha and interleukin 4. Both types of therapy reduced IFNgamma- and IL2-producing CD4 T lymphocytes while IFNgamma-producing CD8 cells remained increased. Even before therapy, these HIV-1-positive patients lacked significant abnormalities in the T cell responsiveness to polyclonal stimuli as well as in the secretion of CCR5 chemokines by peripheral blood mononuclear cells. CONCLUSIONS: Initiating highly active antiretroviral therapy at very early stages of chronic HIV-1 infection allows rapid and almost complete normalization of T cell subsets and preservation of T cell functions. These early-treated patients could be excellent candidates for receiving additional HIV-specific immune-based therapies, which might be essential for the control of HIV infection.

Severe homozygous protein C deficiency: identification of a splice site missense mutation (184, Q-->H) in exon 7 of the protein C gene.

Single strand conformation polymorphism (SSCP) analysis of exon 7 of the protein C gene has identified a novel splice site missense mutation (184, Q-->H), in a newborn child with purpura fulminans and undetectable protein C levels. The mutations, seen in the homozygous state in the child and in the heterozygous state in her mother, was characterized and found to be a G to C nucleotide substitution at the -1 position of the donor splice site of intron 7 of the protein C gene, which changes histidine 184 for glutamine (184, Q-->H). According to analysis of the normal and mutated sequences, this mutation should also abolish the function of the donor splice site of intron 7 of the protein C gene. Since such a mutation is compatible with the absence of gene product in plasma and since DNA sequencing of all protein C gene exons in this patient did not reveal any other mutation, we postulate that mutation 184, Q-->H results in the absence of protein C gene product in plasma, which could be the cause of the severe phenotype observed in this patient.