Ionic currents in hair cells dissociated from frog semicircular canals after preconditioning under microgravity conditions

The effects of microgravity on the biophysical properties of frog labyrinthine hair cells have been examined by analyzing calcium and potassium currents in isolated cells by the patch-clamp technique. The entire, anesthetized frog was exposed to vector-free gravity in a random positioning machine (RPM) and the functional modification induced on single hair cells, dissected from the crista ampullaris, were subsequently studied in vitro. The major targets of microgravity exposure were the calcium/potassium current system and the kinetic mechanism of the fast transient potassium current, IA. The amplitude of ICa was significantly reduced in microgravity-conditioned cells. The delayed current, IKD (a complex of IKV and IKCa), was drastically reduced, mostly in its IKCa component. Microgravity also affected IKD kinetics by shifting the steady-state inactivation curve toward negative potentials and increasing the sensitivity of inactivation removal to voltage. As concerns the IA, the I- V and steady-state inactivation curves were indistinguishable under normogravity or microgravity conditions; conversely, IA decay systematically displayed a two-exponential time course and longer time constants in microgravity, thus potentially providing a larger K+ charge; furthermore, IA inactivation removal at −70 mV was slowed down. Stimulation in the RPM machine under normogravity conditions resulted in minor effects on IKD and, occasionally, incomplete IA inactivation at −40 mV. Reduced calcium influx and increased K+ repolarizing charge, to variable extents depending on the history of membrane potential, constitute a likely cause for the failure in the afferent mEPSP discharge at the cytoneural junction observed in the intact labyrinth after microgravity conditioning.

Nuclear hBD-1 accumulation in malignant salivary gland tumours

Background

Whereas the antimicrobial peptides hBD-2 and -3 are related to inflammation, the constitutively expressed hBD-1 might function as 8p tumour suppressor gene and thus play a key role in control of transcription and induction of apoptosis in malignant epithelial tumours. Therefore this study was conducted to characterise proteins involved in cell cycle control and host defence in different benign and malignant salivary gland tumours in comparison with healthy salivary gland tissue.

Methods

21 paraffin-embedded tissue samples of benign (n = 7), and malignant (n = 7) salivary gland tumours as well as healthy (n = 7) salivary glands were examined immunohistochemically for the expression of p53, bcl-2, and hBD-1, -2, -3.

Results

HBD-1 was distributed in the cytoplasm of healthy salivary glands and benign salivary gland tumours but seems to migrate into the nucleus of malignant salivary gland tumours. Pleomorphic adenomas showed cytoplasmic as well as weak nuclear hBD-1 staining.

Conclusion

HBD-1, 2 and 3 are traceable in healthy salivary gland tissue as well as in benign and malignant salivary gland tumours. As hBD-1 is shifted from the cytoplasm to the nucleus in malignant salivary gland tumours, we hypothesize that it might play a role in the oncogenesis of these tumours. In pleomorphic adenomas hBD-1 might be connected to their biologic behaviour of recurrence and malignant transformation.

Androgen receptors are required for full masculinization of nitric oxide synthase system in rat limbic-hypothalamic region

The neuronal nitric oxide synthase (nNOS) is involved in the control of male and female sexual behavior and its distribution in several regions of the limbic-hypothalamic system, as well as its coexistence with gonadal hormones' receptors, suggests that these hormones may play a significant role in controlling its expression. However, data illustrating the role of gonadal hormones in controlling the nNOS expression are, at present, contradictory, even if they strongly suggest an involvement of testosterone (T) in the regulation of nNOS. The action of T may be mediated through androgen (AR) or, after aromatization to estradiol (E(2)), through estrogen receptors. To elucidate the role of AR on nNOS expression, we compared male and female rats with a non-functional mutation of AR (Tfm, testicular feminization mutation) to their control littermates. We investigated some hypothalamic and limbic nuclei involved in the control of sexual behavior [medial preoptic area (MPA), paraventricular (PVN), arcuate (ARC), ventromedial (VMH) and stria terminalis (BST) nuclei]. In BST (posterior subdivision), VMH (ventral subdivision), and MPA we detected a significant sexual dimorphism in control animals and a decrease of nNOS positive elements in Tfm males compared to their littermate. In addition, we observed a significant increase of nNOS positive elements in BST (posterior) of Tfm females. No significant changes were observed in the other nuclei. These data indicate that, contrary to current opinions, androgens, through the action of AR may have a relevant role in the organization and modulation of the nNOS hypothalamic system.

Decreased gene expression of human beta-defensin-1 in the development of squamous cell carcinoma of the oral cavity

The aim of this study was to investigate the gene expression of human beta-defensin-1, -2, -3 (hBD-1, -2, -3), interleukin-1beta, tumour necrosis factor-alpha and cyclooxygenase-2 in oral squamous cell carcinoma (OSCC) compared to benign and premalignant lesions as well as healthy controls. Biopsies of healthy gingiva (n=5), irritation fibroma (n=5), leukoplakia (n=5) and OSCC (n=5) were obtained during routine surgical procedures. RNA was extracted according to standard protocols and transcripts of hBD-1, -2, -3, interleukin-1beta, tumour necrosis factor-alpha and cyclooxygenase-2 were analysed by real-time polymerase chain reaction. The expression of hBD-1 was reduced in all lesions (5-fold in irritation fibroma and 2.5-fold in leukoplakia), but most significantly (50-fold) in OSCC. hBD-1 appears to play a role in the development of OSCC. The loss of its function might contribute to the malignant progression of these tumours.

[Are journalists more frequently victims of stalking? Results of first empirical examinations]

The lifetime prevalence of stalking is about 12% in the general population. The risk to become a stalking victim is increased for psychiatrists and psychologists. However, there are no studies with regard to other professions. The present study analyses the lifetime prevalence of stalking victimization for journalists, because some professional tasks may also put members of this professional group at a higher risk to become a stalking victim. 493 journalists answered an internet questionnaire. 12% of the journalists reported stalking victimization due to private or other non-professional reasons. This is nearly exactly the same lifetime prevalence that was found in a German community sample. However, 2.2% of the journalists reported stalking victimization that was related to their professional work. This is the first empirical study on this issue. Due to methodological problems no other studies have been published on this topic so far. The reported data of this study have to be interpreted cautiously, because the data are not based on a representative sample. However, comparisons with community-based epidemiological studies render our data a valid basis for starting a discussion of a so far neglected research issue. Our preliminary data suggest that journalists may be at higher risk to become a stalking victim because of their professional activities. Since stalking may cause severe psychological distress in the victims and, in some cases, puts them in severe risk of aggressive violence, preventive strategies should be considered.

Ribosomal protein gene-based phylogeny for finer differentiation and classification of phytoplasmas

Extensive phylogenetic analyses were performed based on sequences of the 16S rRNA gene and two ribosomal protein (rp) genes, rplV (rpl22) and rpsC (rps3), from 46 phytoplasma strains representing 12 phytoplasma 16Sr groups, 16 other mollicutes and 28 Gram-positive walled bacteria. The phylogenetic tree inferred from rp genes had a similar overall topology to that inferred from the 16S rRNA gene. However, the rp gene-based tree gave a more defined phylogenetic interrelationship among mollicutes and Gram-positive walled bacteria. Both phylogenies indicated that mollicutes formed a monophyletic group. Phytoplasmas clustered with Acholeplasma species and formed one clade paraphyletic with a clade consisting of the remaining mollicutes. The closest relatives of mollicutes were low-G+C-content Gram-positive bacteria. Comparative phylogenetic analyses using the 16S rRNA gene and rp genes were performed to evaluate their efficacy in resolving distinct phytoplasma strains. A phylogenetic tree was constructed based on analysis of rp gene sequences from 87 phytoplasma strains belonging to 12 16Sr phytoplasma groups. The phylogenetic relationships among phytoplasmas were generally in agreement with those obtained on the basis of the 16S rRNA gene in the present and previous works. However, the rp gene-based phylogeny allowed for finer resolution of distinct lineages within the phytoplasma 16Sr groups. RFLP analysis of rp gene sequences permitted finer differentiation of phytoplasma strains in a given 16Sr group. In this study, we also designed several semi-universal and 16Sr group-specific rp gene-based primers that allow for the amplification of 11 16Sr group phytoplasmas.

Instruments and accessories for diagnostic endoscopic ultrasound (radial scanning and miniprobes)

Endoscopic ultrasound (EUS) is a relatively new technology developed in the early 80's, but introduced into the clinical practice only in the late 80's. Nowadays there is an increase in demand for EUS examinations and services, because this technique is more and more recognized as an important and integral part in the diagnostic and staging algorithm of many gastrointestinal (GI) and nongastrointestinal pathologies. Even if today the EUS panorama enrich itself with a large number of different instruments, mechanical and electronic scopes, radial and linear ones, several types of miniprobes and specialty probes, for diagnostic purposes the dedicated radial scanning instruments remain the more adopted choice while miniprobes can have applications only in niche areas, like superficial GI cancers staging, small subepithelial lesions evaluation or intraductal ultrasound and some technological advances are needed to solve the potential drawbacks of this miniaturized probes. At last the EUS equipment borrowed most of the electronic sophistication from the mainstream ultrasonography, this made the choice of an EUS instrument even more difficult and challenging, but you must consider that there is no right or wrong equipment, there is only the right instrument for that specific clinical need or situation.

On the role of H2O2 in the recovery of grapevine (Vitis vinifera cv. Prosecco) from Flavescence dorée disease

In the present work, we compared hydrogen peroxide (H₂O₂) localisation and the activities/contents of antioxidant enzymes and metabolites in the leaf tissues of grapevine (Vitis vinifera L. cv. Prosecco) plants showing different sanitary status, namely diseased by Flavescence dorée, healthy or recovered. Polymerase chain reaction analysis revealed that the pathogen associated with Flavescence dorée (proposed as 'Candidatus Phytoplasma vitis') was detected in the leaf tissues of symptomatic plants, but was not observed in either the healthy or recovered plants. Hydrogen peroxide accumulated in the phloem plasmalemma of recovered grapevine leaves, but was not detected in either healthy or diseased material. When compared to diseased or healthy plants, recovered plants had distinctly lower extractable levels of catalase and ascorbate peroxidase, two enzymes primarily involved in the scavenging of excess H₂O₂ generated in different cell compartments. Among healthy, diseased and recovered leaves there was no significant difference in the amount of 2-thiobarbituric acid-reactive substances, which are assumed to reflect the extent of peroxidative breakdown of membrane lipids. Therefore, it is suggested that recovery from Flavescence dorée disease in grapevine might be associated with a long-term, sustained and tissue-specific accumulation of H₂O₂ in leaves, which reduces numbers or prevents further infection by Flavescence dorée phytoplasma. Recovered grapevine plants might be able to achieve such H₂O₂ accumulation through a selective and presumably stable downregulation of enzymatic H₂O₂ scavengers, without altering the levels of other antioxidant systems and without incurring an increased oxidative risk.

Polymorphism in cytokine genes as prognostic markers in Hodgkin's lymphoma

BACKGROUND

In Hodgkin's lymphoma (HL), the production of cytokines by Reed-Sternberg cells and the surrounding tissue is thought to contribute to the biology of the disease. Cytokine expression can be altered by common single nucleotide polymorphisms (SNPs) in the 5'-promoter regions.

PATIENTS AND METHODS

We studied polymorphic allele variants of the cytokine genes interleukin (IL)-10 (T-3575A, G-2849A, C-2763A, A-1082G and C-592A), IL-6 (G-174C) and tumor necrosis factor-alpha (C-863A and G-308A) in 184 patients with HL, and analyzed for associations with treatment outcome.

RESULTS

Carriers of the IL-10-592AA and the IL-6-174GG genotypes had a significantly lower probability of freedom from treatment failure (FFTF) with adjusted hazard ratios (HRs) for failure of 2.92 [95% CI (confidence interval) 1.58-5.41, P = 0.001] and of 1.75 (95% CI 1.04-2.92, P = 0.03), respectively. Reconstructing haplotypes from the five SNPs in the IL-10 promoter revealed that homozygous carriers of the IL-10.4 haplotype (T-G-C-A-A) had a worse FFTF (HR, 2.35; 95% CI 1.2-4.6, P = 0.01). In the Cox multivariate analysis, the IL-10-592AA, the IL-6-174GG genotypes and stage were independent prognostic factors.

CONCLUSIONS

Our study indicates that cytokine genotypes predict clinical outcome in patients with HL and points to the importance of the genetic background of the host for treatment response.

High prognostic potential of glioblastoma stem cell analysis

10580

Background: Cancer stem cells (CSCs) are a rare cell population responsible for tumor development and maintenance. Recent studies have shown that glioblastoma stem cells express the CD133 marker and are resistant to radiotherapy and chemotherapy. However, clinical data based on the study of CSCs in patients with glioblastoma are not available yet. Methods: Glioblastoma samples from 44 patients treated with complete or partial tumorectomy, followed by radiotherapy and temozolomide were prospectively analyzed. Immunohistochemistry was performed to evaluate the prognostic value of the number of CD133+ cells present in tumors. Moreover, the relationship between the ability to generate long-term culture of tumorigenic cells in vitro and the clinical outcome of glioblastoma patients was tested. Results: CD133 expression did not show an overall prognostic value. CSC cultures were obtained from 14 of the 44 tumors (32%). The generation of CSCs emerged as significant independent prognostic factor by the Cox multivariate analyses, with an adjusted hazard ratio of 2.50 (95% CI, 1.04 to 6.06; P=0.004). The median overall survival among patients with tumors generating CSCs was 8.0 months (95% CI, 4.0 to 11.5), as compared with 15 months (95% CI, 11.0 to 19.0) among those without generation of CSCs (P=0.0002). The median progression-free survival was 3.5 months (95% CI, 2.0 to 6.0) for glioblastoma generating CSCs and 9.0 months (95% CI, 7.0 to 12.0) for glioblastoma not generating CSCs (P=0.0001). A higher CD133 expression significantly associated with tumors generating CSCs (P=0.006), and correlated with a higher risk of death in patients with tumors generating CSCs in vitro (hazard ratio of 1.65, 95% CI, 1.05 to 2.60; P=0.0285). Conclusions: Generation of long-term culture of tumorigenic CSCs in vitro from glioblastoma predicts a poor clinical outcome for patients, in terms of both overall and progression-free survival. In tumors generating CSCs, CD133 expression may have a prognostic value.

No significant financial relationships to disclose.

Ca2+ current of frog vestibular hair cells is modulated by intracellular ATP but not by long-lasting depolarisation

Some aspects of Ca(2+) channel modulation in hair cells isolated from semicircular canals of the frog (Rana esculenta) have been investigated using the whole-cell technique and intra and extracellular solutions designed to modify the basic properties of the Ca(2+) macrocurrent. With 1 mM ATP in the pipette solution, about 60% of the recorded cells displayed a Ca(2+) current constituted by a mix of an L and a drug-resistant (R2) component; the remaining 40% exhibited an additional drug-resistant fraction (R1), which inactivated in a Ca-dependent manner. If the pipette ATP was raised to 10 mM, cells exhibiting the R1 current fraction displayed an increase of both the R1 and L components by approximately 280 and approximately 70%, respectively, while cells initially lacking R1 showed a similar increase in the L component with R1 becoming apparent and raising up to a mean amplitude of approximately 44 pA. In both cell types the R2 current fraction was negligibly affect by ATP. The current run-up was unaffected by cyclic nucleotides, and was not triggered by 10 mM ATPgammaS, ADP, AMP or GTP. Long-lasting depolarisations (>5 s) produced a progressive, reversible decay in the inward current despite the presence of intracellular ATP. Ca(2+) channel blockade by Cd(2+) unmasked a slowly activating outward Cs(+) current flowing through a non-Ca(2+) channel type, which became progressively unblocked by prolonged depolarisation even though Cs(+) and TEA(+) were present on both sides of the channel. The outward current waveform could be erroneously ascribed to a Ca- and/or voltage dependence of the Ca(2+) macrocurrent.

Potassium currents in the hair cells of vestibular epithelium: position-dependent expression of two types of A channels

The complement of voltage-dependent K+ currents was investigated in hair cells of the frog crista ampullaris. The currents were recorded in transversal slices of the peripheral, intermediate and central regions of the crista by applying the patch clamp technique to cells located at different positions in the slices. Voltage-clamp recordings confirmed that cells located in each region have a distinctive complement of K+ channels. Detailed investigation of the currents in each region revealed that the complement of K+ channels in intermediate and central regions showed no variations among cells, whereas peripheral hair cells differed in the expression of two classes of A-type currents. These currents showed different kinetics of inactivation as well as steady-state inactivation properties. We termed these currents fast I(A) and slow I(A) based on their inactivation speed. The magnitude of both currents exhibited a significant gradient along the transversal axis of the peripheral regions. Fast I(A) magnitude was maximal in cells located in the external zone of the crista slice and decreased gradually to become very small in the median zone (centre) of the section, while the gradient of slow I(A) magnitude was reversed. A-type currents appear to act as a transient buffer that opposes hair cell depolarization induced by positive current injections. However, fast I(A) is partially active at the cell resting potential, while slow I(A) can be recruited only following large hyperpolarizations. Thus, two types of A currents are differentially distributed in vestibular hair cells and have different roles in shaping receptor potential.

Reduced BRCA1 expression due to promoter hypermethylation in therapy-related acute myeloid leukaemia

BRCA1 plays a pivotal role in the repair of DNA damage, especially following chemotherapy and ionising radiation. We were interested in the regulation of BRCA1 expression in acute myeloid leukaemia (AML), in particular in therapy-related forms (t-AML). Using real-time PCR and Western blot, we found that BRCA1 mRNA was expressed at barely detectable levels by normal peripheral blood granulocytes, monocytes and lymphocytes, whereas control BM-mononuclear cells and selected CD34+ progenitor cells displayed significantly higher BRCA1 expression (P=0.0003). Acute myeloid leukaemia samples showed heterogeneous BRCA1 mRNA levels, which were lower than those of normal bone marrows (P=0.0001). We found a high frequency of hypermethylation of the BRCA1 promoter region in AML (51/133 samples, 38%), in particular in patients with karyotypic aberrations (P=0.026), and in t-AML, as compared to de novo AML (76 vs 31%, P=0.0002). Examining eight primary tumour samples from hypermethylated t-AML patients, BRCA1 was hypermethylated in three of four breast cancer samples, whereas it was unmethylated in the other four tumours. BRCA1 hypermethylation correlated to reduced BRCA1 mRNA (P=0.0004), and to increased DNA methyltransferase DNMT3A (P=0.003) expression. Our data show that reduced BRCA1 expression owing to promoter hypermethylation is frequent in t-AML and that this could contribute to secondary leukaemogenesis.

Prognostic significance of downregulated expression of the candidate tumour suppressor gene SASH1 in colon cancer

The gene SASH1 (SAM- and SH3-domain containing 1) has originally been identified as a candidate tumour suppressor gene in breast cancer. SASH1 is a member of the SH3-domain containing expressed in lymphocytes (SLY1) gene family that encodes signal adapter proteins composed of several protein–protein interaction domains. The other members of this family are expressed mainly in haematopoietic cells, whereas SASH1 shows ubiquitous expression. We have used quantitative real-time PCR to investigate the expression of SASH1 in tissue samples from 113 patients with colon carcinoma, and compared the expression with 15 normal colon tissue samples. Moreover, nine benign adenomas and 10 liver metastases were analysed. Expression levels of SASH1 were strongly and significantly reduced in colon cancer of UICC stage II, III, and IV, as well as in liver metastases. Moreover, SASH1 was also found to be downregulated on protein levels by immunoblot analysis. However, SASH1 expression was not significantly deregulated in precancerous adenomas and in earlier stage lesions (UICC I). Overall, 48 out of 113 primary colon tumours showed SASH1 expression that was at least 10-fold lower than the levels found in normal colon tissue. Downregulation of SASH1 expression was correlated with the formation of metachronous distant metastasis, and multivariate analysis identified SASH1 downregulation as an independent negative prognostic parameter for patient survival. This study demonstrates for the first time that expression of a member of the SLY1-gene family has prognostic significance in human cancer.