72 research outputs found
The Great Space Weather Event during February 1872 Recorded in East Asia
The study of historical great geomagnetic storms is crucial for assessing the
possible risks to the technological infrastructure of a modern society, caused
by extreme space-weather events. The normal benchmark has been the great
geomagnetic storm of September 1859, the so-called "Carrington Event". However,
there are numerous records of another great geomagnetic storm in February 1872.
This storm, about 12 years after the Carrington Event, resulted in comparable
magnetic disturbances and auroral displays over large areas of the Earth. We
have revisited this great geomagnetic storm in terms of the auroral and sunspot
records in the historical documents from East Asia. In particular, we have
surveyed the auroral records from East Asia and estimated the equatorward
boundary of the auroral oval to be near 24.3 deg invariant latitude (ILAT), on
the basis that the aurora was seen near the zenith at Shanghai (20 deg magnetic
latitude, MLAT). These results confirm that this geomagnetic storm of February
1872 was as extreme as the Carrington Event, at least in terms of the
equatorward motion of the auroral oval. Indeed, our results support the
interpretation of the simultaneous auroral observations made at Bombay (10 deg
MLAT). The East Asian auroral records have indicated extreme brightness,
suggesting unusual precipitation of high-intensity, low-energy electrons during
this geomagnetic storm. We have compared the duration of the East Asian auroral
displays with magnetic observations in Bombay and found that the auroral
displays occurred in the initial phase, main phase, and early recovery phase of
the magnetic storm.Comment: 28 pages, 5 figures, accepted for publication in the Astrophysical
Journal on 31 May 201
TRH: Pathophysiologic and clinical implications
Thyrotropin releasing hormone is thought to be a tonic stimulator of the pituitary TSH secretion regulating the setpoint of the thyrotrophs to the suppressive effect of thyroid hormones. The peptide stimulates the release of normal and elevated prolactin. ACTH and GH may increase in response to exogenous TRH in pituitary ACTH and GH hypersecretion syndromes and in some extrapituitary diseases.
The pathophysiological implications of extrahypothalamic TRH in humans are essentially unknown.
The TSH response to TRH is nowadays widely used as a diganostic amplifier in thyroid diseases being suppressed in borderline and overt hyperthyroid states and increased in primary thyroid failure. In hypothyroid states of hypothalamic origin, TSH increases in response to exogenous TRH often with a delayed and/or exaggerated time course.
But in patients with pituitary tumors and suprasellar extension TSH may also respond to TRH despite secondary hypothyroidism. This TSH increase may indicate a suprasellar cause for the secondary hypothyroidism, probably due to portal vessel occlusion. The TSH released in these cases is shown to be biologically inactive
Tertiary hypothyroidism and hyperglycemia in mice with targeted disruption of the thyrotropin-releasing hormone gene
Influence of combined therapy with conventional and herbal medicines on liver function in 138 inpatients with abnormal liver transaminase levels
The effects of histamine on the concentrations of immunoreactive thyrotropin-releasing hormone in the stomach and hypothalamus in rats
Course and distribution of facial corticobulbar tract fibres in the lower brain stem
The course and distribution of the facial corticobulbar tract (CBT) was examined by correlating MRI of brain stem lesions with neurological symptoms and signs including central (C-FP) or peripheral facial paresis (P-FP) in 70 patients with localised infarction of the lower brain stem. C-FP occurred more often in patients with lesions of the lower pons or upper medulla of the ventromedial brain stem. Some patients with dorsolateral infarcts of the upper medulla to the lower pons showed C-FP, mostly on the lesion side. P-FP on the side of the lesion was also seen in patients with dorsolateral involvement of the lower pons. Patients with ventromedial infarction of the brain stem showed paresis of extremities contralateral to the lesion. Specific neurological symptoms and signs such as dysphagia, vertigo, nystagmus, Horner's syndrome, ipsilateral cerebellar ataxia, and contralateral superficial sensory impairment were seen in patients with dorsolateral infarcts of the brain stem. It is hypothesised that the facial CBT descends at the ventromedial lower pons, near the corticospinal tract, mainly to the level of the upper medulla, where the fibres then decussate and ascend in the dorsolateral medulla to synapse in the contralateral facial nucleus.âš
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