38 research outputs found

    Molecular cloning and sequence analysis of multiple cDNA variants for thyroid-stimulating hormone β subunit (TSHβ) in the fathead minnow \u3cem\u3e(Pimephales promelas)\u3c/em\u3e

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    We cloned and sequenced full-length cDNAs encoding the β subunit of thyroid-stimulating hormone (TSHβ) from the pituitary of fathead minnow (Piephales promelas)using 5\u27-and 3\u27-rapid amplification of cDNA ends (RACE). Three cDNA variants for TSHβ with lengths of 1184-, 1093-, and 818-bp were identified. The cDNA variant of 1184-bp included 453-bp of open-reading frame and 610-bp of 3\u27 UTR followed by a poly(A)site. This cDNA encodes 150 amino acids including a 19 residue signal peptide and a mature TSHβ protein of 131 residues with sequence identities of 97–53% to other fishes and 42–39% to mammals. The 1093-bp cDNA variant was identical to the 1184-bp variant in the open-reading frame, but contained a deletion of 40-bp in the 3\u27 UTR. The 818-bp cDNA variant, however, contained 498-bp of open-reading frame followed by 227-bp of 3\u27 UTR and a poly(A)site. The deduced amino acid sequence for this cDNA variant showed 99.2% homology with the 1184-and 1093-bp variants of TSHβ, but a single deletion of 332bp nucleotides spanning the predicted stop codon and 3\u27 UTR resulted in a deduced amino acid sequence with 15 additional residues on the C terminus. The presence of this 818-bp cDNA variant in the pituitary was further confirmed by PCR using primers developed to the 5\u27 and 3\u27 UTR. PCR and Southern blot analyses of genomic DNA suggested only one gene for TSHβ. Sequencing of this gene revealed a hairpin loop structure of approximately 300-bp located in the 3\u27 UTR and corresponding to the region of the 332-bp deletion in the 818-bp transcript

    Ferroelectric domain nucleation and switching pathways in hafnium oxide

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    Nanoscale ferroelectrics that can be integrated into microelectronic fabrication processes are highly desirable for low-power computing and non-volatile memory devices. However, scalable novel ferroelectric materials, such as hafnium oxide (HfO2), remain in a state of development, and a clear understanding of the effects of relevant compositional and processing parameters to control their ferroelectric properties and the actual polarization switching mechanisms are still under investigation. One key fundamental knowledge gap is the polarization switching pathway in ferroelectric hafnia. To further our fundamental understanding of domain nucleation and switching, we have studied polarization switching pathways in HfO2-x thin films in real-time at the atomic scale using transmission electron microscopy. We employed differential phase contrast imaging that allows for the acquisition of both hafnium and oxygen atomic column signals and facilitates the observation of relative movement of atomic columns between both sublattices. Our results demonstrate that the switching pathway involves a transient tetragonal-like local structure, as oxygen ions shift in locations and remain within their parent hafnium polyhedra

    Robot assisted MRI-guided LITT of the anterior, lateral, and medial temporal lobe for temporal lobe epilepsy

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    Robotic systems have fundamentally altered the landscape of functional neurosurgery. These allow automated stereotaxy with high accuracy and reliability, and are rapidly becoming a mainstay in stereotactic surgeries such as deep brain stimulation (DBS), stereoelectroencephalography (SEEG), and stereotactic laser ablation/MRI guided laser interstitial thermal therapy (MRgLITT). Robotic systems have been effectively applied to create a minimally invasive approach for diagnostics and therapeutics in the treatment of epilepsy, utilizing robots for expeditious and accurate stereotaxy for SEEG and MRgLITT. MRgLITT has been shown to approach open surgical techniques in efficacy of seizure control while minimizing collateral injury. We describe the use of robot assisted MRgLITT for a minimally invasive laser anterior temporal lobotomy, describing the approach and potential pitfalls. Goals of MRgLITT are complete ablation of the epileptogenic zone and avoiding injury to uninvolved structures. In the middle fossa these include structures such as cranial nerves in the skull base and cavernous sinus and the thalamus. These can be mitigated with careful trajectory planning and control of laser ablation intensity

    Self-love and sociability: the ‘rudiments of commerce’ in the state of nature

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    Istvan Hont’s classic work on the theoretical links between the seventeenth-century natural jurists Hugo Grotius and Samuel Pufendorf and the eighteenth-century Scottish political economists remains a popular trope among intellectual and economic historians of various stamps. Despite this, a common criticism levelled at Hont remains his relative lack of engagement with the relationship between religion and economics in the early modern period. This paper challenges this aspect of Hont’s narrative by drawing attention to an alternative, albeit complementary, assessment of the natural jurisprudential heritage of eighteenth-century British political economy. Specifically, the article attempts to map on to Hont’s thesis the Christian Stoic interpretation of Grotius and Pufendorf which has gained greater currency in recent years. In doing so, the paper argues that Grotius and Pufendorf’s contributions to the ‘unsocial sociability’ debate do not necessarily lead directly to the Scottish school of political economists, as is commonly assumed. Instead, it contends that a reconsideration of Grotius and Pufendorf as neo-Stoic theorists, particularly via scrutiny of their respective adaptations of the traditional Stoic theory of oikeiosis, steers us towards the heart of the early English ‘clerical’ Enlightenment

    Nanoparticle-induced neuronal toxicity across placental barriers is mediated by autophagy and dependent on astrocytes

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    The potential for maternal nanoparticle (NP) exposures to cause developmental toxicity in the fetus without the direct passage of NPs has previously been shown, but the mechanism remained elusive. We now demonstrate that exposure of cobalt and chromium NPs to BeWo cell barriers, an in vitro model of the human placenta, triggers impairment of the autophagic flux and release of interleukin-6. This contributes to the altered differentiation of human neural progenitor cells and DNA damage in the derived neurons and astrocytes. Crucially, neuronal DNA damage is mediated by astrocytes. Inhibiting the autophagic degradation in the BeWo barrier by overexpression of the dominant-negative human ATG4BC74A significantly reduces the levels of DNA damage in astrocytes. In vivo, indirect NP toxicity in mice results in neurodevelopmental abnormalities with reactive astrogliosis and increased DNA damage in the fetal hippocampus. Our results demonstrate the potential importance of autophagy to elicit NP toxicity and the risk of indirect developmental neurotoxicity after maternal NP exposure

    Thyroid hormone regulation of mRNAs encoding thyrotropin β-subunit, glycoprotein α-subunit, and thyroid hormone receptors α and β in brain, pituitary gland, liver, and gonads of an adult teleost, Pimephales promelas

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    Thyroid hormones (THs) regulate growth, morphological development, and migratory behaviors in teleost fish, yet little is known about the transcriptional dynamics of gene targets for THs in these taxa. Here, we characterized TH regulation of mRNAs encoding thyrotropin subunits and thyroid hormone receptors (TRs) in an adult teleost fish model, the fathead minnow (Pimephales promelas). Breeding pairs of adult minnows were fed diets containing 3,5, 3,-triiodo-L-thyronine (T3) or the goitrogen methimazole for 10 days. In males and females, dietary intake of exogenous T3 elevated circulating total T3, while methimazole depressed plasma levels of total thyroxine (T4). In both sexes, this methimazole-induced reduction in T4 led to elevated mRNA abundance for thyrotropin β-subunit (tshβ) in the pituitary gland. Fish treated with T3 had elevated transcript levels for TR isoforms α and β (trα and trβ) in the liver and brain, but reduced levels of brain mRNA for the immediate-early gene basic transcription factor-binding protein (bteb). In the ovary and testis, exogenous T3 elevated gene transcripts for tshβ, glycoprotein hormone α-subunit (gphα), and trβ, while not affecting trα; levels. Taken together, these results demonstrate negative feedback of T4 on pituitary tshβ, identify trα and trβ as T3-autoinduced genes in the brain and liver, and provide new evidence that tshβ, gphα, and trβ are THs regulated in the gonad of teleosts. Adult teleost models are increasingly used to evaluate the endocrine-disrupting effects of chemical contaminants, and our results provide a systemic assessment of TH-responsive genes during that life stage

    Dietary Exposure to 2,2′,4,4′-Tetrabromodiphenyl Ether (PBDE-47) Alters Thyroid Status and Thyroid Hormone–Regulated Gene Transcription in the Pituitary and Brain

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    BACKGROUND: Polybrominated diphenyl ether (PBDE) flame retardants have been implicated as disruptors of the hypothalamic-pituitary-thyroid axis. Animals exposed to PBDEs may show reduced plasma thyroid hormone (TH), but it is not known whether PBDEs impact TH-regulated pathways in target tissues. OBJECTIVE: We examined the effects of dietary exposure to 2,2′,4,4′-tetrabromodiphenyl ether (PBDE-47)—commonly the highest concentrated PBDE in human tissues—on plasma TH levels and on gene transcripts for glycoprotein hormone α-subunit (GPHα) and thyrotropin β-subunit (TSHβ) in the pituitary gland, the autoinduced TH receptors α and β in the brain and liver, and the TH-responsive transcription factor basic transcription element-binding protein (BTEB) in the brain. METHODS: Breeding pairs of adult fathead minnows (Pimephales promelas) were given dietary PBDE-47 at two doses (2.4 μg/pair/day or 12.3 μg/pair/day) for 21 days. RESULTS: Minnows exposed to PBDE-47 had depressed plasma thyroxine (T(4)), but not 3,5,3′-triiodothyronine (T(3)). This decline in T(4) was accompanied by elevated mRNA levels for TStHβ (low dose only) in the pituitary. PBDE-47 intake elevated transcript for TH receptor αin the brain of females and decreased mRNA for TH receptor β in the brain of both sexes, without altering these transcripts in the liver. In males, PBDE-47 exposure also reduced brain transcripts for BTEB. CONCLUSIONS: Our results indicate that dietary exposure to PBDE-47 alters TH signaling at multiple levels of the hypothalamic-pituitary-thyroid axis and provide evidence that TH-responsive pathways in the brain may be particularly sensitive to disruption by PBDE flame retardants
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