Usefulness and limitations of pollen characters in environmental studies based on Viola L. species (sect. Melanium Ging.)

The aim of these studies was to determine the effect of environmental pollution on pollen development. Pollen heteromorphism (the presence of pollen morphs differing in aperture number in one flower of a plant), pollen viability (stainability) and pollen grain size in European metallophytes from sect. Melanium Ging. (Viola L., Violaceae) were analyzed by SEM and histochemical staining.Plants’ tolerance to heavy metals is positively correlated with their pollen viability, which should be termed stainability as it depends on the staining method applied and is not correlated with pollen germination. Abortive pollen can be produced as an effect of heavy metals but also may result from hybridization, a very common phenomenon in pansies. Pollen stainability in hybrids can be high (even exceeding 70%) or low (barely above 20%), and stainable pollen grains can differ greatly in size (from very small to giant), indicating a cytological imbalance resulting from disturbed meiosis. The number of pollen apertures is an adaptive character in facultative metallophytes. Plants from a metallicolous population produced a wider range of aperture number (3, 4, 5) than plants from a non-metallicolous population, which developed only 4- and 5-aperturate pollen. Three-aperturate longer-lived pollen are favored in the harsh conditions of a metal-polluted environment

Arabinogalactan-protein and pectin epitopes in relation to an extracellular matrix surface network and somatic embryogenesis and callogenesis in Trifolium nigrescens Viv

The formation of an extracellular matrix surface network (ECMSN), and associated changes in the distribution of arabinogalactan-protein and pectin epitopes, have been studied during somatic embryogenesis (SE) and callogenesis of Trifolium nigrescens Viv. Scanning electron microscopy observations revealed the occurrence of an ECMSN on the surface of cotyledonary-staged somatic embryos as well as on the peripheral, non-regenerating callus cells. The occurrence of six AGP (JIM4, JIM8, JIM13, JIM16, LM2, MAC207) and four pectin (JIM5, JIM7, LM5, LM6) epitopes was analysed during early stages of SE, in cotyledonary-staged somatic embryos and in non-embryogenic callus using monoclonal antibodies. The JIM5 low methyl-esterified homogalacturonan (HG) epitope localized to ECMSN on the callus surface but none of the epitopes studied were found to localize to ECMSN over mature somatic embryos. The LM2 AGP epitope was detected during the development of somatic embryos and was also observed in the cell walls of meristematic cells from which SE was initiated. The pectic epitopes JIM5, JIM7, LM5 and LM6 were temporally regulated during SE. The LM6 arabinan epitope, carried by side chains of rhamnogalacturonan-I (RG-I), was detected predominantly in cells of embryogenic swellings, whilst the LM5 galactan epitope of RG-I was uniformly distributed throughout the ground tissue of cotyledonary-staged embryoids but not detected at the early stages of SE. Differences in the distribution patterns of low and high methyl-esterified HG were detected: low ester HG (JIM5 epitope) was most abundant during the early steps of embryo formation and highly methyl-esterified form of HG (JIM7 epitope) became prevalent during embryoid maturation

The TT genotype of methylenetetrahydrofolate reductase 677C>T polymorphism increases the susceptibility to pediatric ischemic stroke: meta-analysis of the 822 cases and 1,552 controls

The 677C>T polymorphism within methylenetetrahydrofolate reductase (MTHFR) gene is related to an elevated level of homocysteine. Thus it may be considered as a genetic risk factor in ischemic stroke. Apparently studies of this type of polymorphism in childhood stroke have shown conflicting results. We performed meta-analysis of all the data that are available in relation with MTHFR polymorphism and the risk of ischemic stroke in children. We searched PubMed (last search dated December 2010) using “MTHFR polymorphism”, “ischemic stroke” “child”, “children”, “pediatric stroke” as keywords and reference lists of studies and reviews on the topic. Finally, 15 case–control studies corresponded to the inclusion criteria for meta-analysis. These studies involved the total number of 822 children and adolescents after ischemic stroke and 1,552 control subjects. Fixed or random effects models were used depending on the heterogeneity between the studies. The association between ischemic stroke and 677C>T polymorphism within MTHFR gene was observed in three of the studies. The pooled analysis showed that TT genotype of MTHFR gene is more common in stroke patients than in controls (p = 0.0402, odds ratio = 1.57, 95 % confidence interval 1.02–2.41). The Egger’s test did not reveal presence of a publication bias. The results based on a sizeable group of cases and controls have proved that the 677C>T polymorphism in MTHFR gene is associated with the development of ischemic stroke in children

Radiotherapy in the treatment of Graves ophthalmopathy—to do it or not?

To the objective of this study is to evaluate the role and toxicity of radiotherapy in the treatment of Graves ophthalmopathy. In the years 2000–2003, 121 patients with malignant exophthalmos were treated with radiotherapy of the retrobulbar area to the total dose of 20 Gy in ten fractions with a 6 MeV photon beam. The treatment was performed by the team of the Clinic of Oncology of the Jagiellonian University Medical College in Cracow. The radiotherapy was preceded by intravenous steroid therapy: methylprednisolone acetate administered at the dose of 2 g/week for four consecutive weeks. The highest efficacy, expressed as improvement of all ocular symptoms, was observed for the combined treatment. Female and non-diabetic patients responded positively to the combined treatment. Radiotherapy combined with steroid therapy in the treatment of Graves ophthalmopathy seems to be an effective treatment for strictly defined indications. In the treatment of Graves–Basedow disease, radiotherapy is a well-tolerated treatment modality. Diabetes is a factor that worsens prognosis in Graves ophthalmopathy and female sex is a favourable factor for this condition

Interaction between Tobacco and Alcohol Use and the Risk of Head and Neck Cancer: Pooled Analysis in the International Head and Neck Cancer Epidemiology Consortium

The magnitude of risk conferred by the interaction between tobacco and alcohol use on the risk of head and neck cancers is not clear, since studies have used various methods to quantify the excess head and neck cancer burden