Contribution of the adrenal gland to the production of androstenedione and testosterone during the first two years of life

Androstenedione and testosterone were measured in whole adrenal glands of 56 previously healthy boys who died suddenly between birth and 2 yr of age. In each adrenal gland, the concentration of androstenedione considerably exceeded that of testosterone. The highest concentrations were found during the first week of life (median, 295 ng/g; range, 98- 320 ng/g). Thereafter, values decreased rapidly until the end of the first year of life (median, 10 ng/g; range, 4.4-22.7 ng/g). Adrenal testosterone concentrations averaged 15% of those of androstenedione in the same gland and similarly decreased until the end of the first year. The decrease of adrenal androgen concentrations paralleled the involution of the fetal adrenal zone. A close correlation existed between the concentration of androstenedione in adrenal tissue and plasma. However, no correlation existed between adrenal and plasma testosterone. When the adrenals and testes of the same infant were compared, there was 10 times more androstenedione in the adrenals than in the testes during the first 2 yr of life. The testes contained more testosterone than the adrenals only during the first 4 months. Thus, in infant boys the adrenals are the main source of androstenedione during the first 2 yr. After the sixth month of life, they also are the main source of testosterone

Testosterone and androstenedione concentrations in human testis and epididymis during the first two years of life

Testosterone and androstenedione were measured in testicular and epididymal tissue of 37 previously healthy infants between 1 and 24 months of age who died suddenly. In half of the patients elevated plasma levels of cortisol and androstenedione suggested preterminal stress. Plasma testosterone levels, however, did not differ from those in healthy infants. Testicular testosterone concentrations were maximal in boys from 1-3 months of age (median, 36.6 ng/g; range, 7-380 ng/g) with peak values similar to those found in pubertal or even adult testes. Thereafter testicular testosterone concentrations decreased and after the age of 6 months all values were below 12.5 ng/g, which corresponds to the low normal range of older prepubertal boys. Plasma testosterone and testicular testosterone correlated significantly (P less than 0.001). On average the testicular concentrations were 36.4 times higher than the corresponding plasma concentrations. Testicular androstenedione was low but correlated significantly with testicular testosterone (P less than 0.001). Epididymal testosterone concentrations were surprisingly high (1-3 months: median, 10.3 ng/g; range, 4-42.7 ng/g) and averaged 30% of the testicular testosterone concentration. Thus, epididymal testosterone concentrations were significantly higher than the circulating plasma testosterone levels, indicating the capacity of the infant epididymis to accumulate androgens. These findings suggest that high local testosterone concentrations during early infancy are important not only for the testis itself but particularly for the developing epididymi

S-Matrix Poles Close to Thresholds in Confined Geometries

We have studied the behavior of the S-matrix poles near threshold for quantum waveguides coupled to a cavity with a defect. We emphasize the occurrence of both dominant and shadow poles on the various sheets of the energy Riemann surface, and show that the changes of the total conductivity near threshold as the cavity's width changes can be explained in terms of dominant to shadow pole transitions.Comment: 10 pages, 5 figure

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Paleotethys was a highly mobile oceanic realm pinching into the supercontinent Pangea between Gondwana and Eurasia in the late Paleozoic/early Mesozoic. Published Paleotethyan reconstructions reveal that the time of Paleotethys closure and the position of its suture are highly debated. We present new magmatic and detrital zircon ages, separated from pre-Alpine basement and Permian to Triassic cover rocks exposed in the External Hellenides of Crete. These age data reveal Variscan and Cimmerian docking of microplates along the southern margin of Laurasia and help to constrain the time of Paleotethys closure.46% of detrital zircons from quartzite in the Variscan basement, are Pennsylvanian with concordant ages at 321. ±. 2. Ma, 310. ±. 3. Ma, and 300. ±. 3. Ma. The basement is unconformably overlain by arc-related volcanics of the Tyros Unit, magmatic zircons of which yielded a concordant U-Pb zircon age at 285. ±. 2. Ma. Thus, the metasediments of the basement, interpreted as former trench sediments, were deposited, metamorphosed and exhumed in latest Carboniferous to early Permian times (302-283. Ma). Magmatic activity during this late Variscan phase is also indicated by igneous boulders within Olenekian (meta)conglomerates of the Tyros Unit, which yielded concordant U-Pb zircon ages at 291. ±. 2 and 310. ±. 2. Ma. The late Variscan orogenic phase is attributed to the collision of the Gondwana-derived southern Minoan terrane (SMT) with Laurasia subsequent to northward subduction of Paleotethys lithosphere and Viséan collision of the northern Minoan terrane (NMT).Magmatic activity ceased during the late Permian, but revived in the Lower Triassic as is indicated by felsic volcanics (249. ±. 2. Ma, concordant U-Pb zircon) and by detrital zircons (242. ±. 3, 240. ±. 5. Ma, 237. ±. 3. Ma concordant U-Pb zircon) of the Tyros Unit. At the same time the Variscan chain was exhumed and removed as is shown by the detritus in the Lower to Middle Triassic Tyros sediments, which includes high-grade metamorphic rocks and detrital zircons with U-Pb ages ranging from 280 to 335. Ma.A significant change in the detrital components occurred in the Ladinian when the Variscan basement with its Permo-Triassic cover was thrust on top of clastic sediments, today represented by the Phyllite-Quartzite Unit s.str. The Phyllite-Quartzite Unit s.str. shows Cadomian and older - but no Variscan - detritus because of its position along the northern margin of the Cimmerian ribbon continent. Thus, in the eastern Mediterranean, Paleotethys was closed during the Ladinian and the related suture in the External Hellenides is situated between the Variscan basement (active margin in the north) and the Phyllite-Quartzite Unit s.str (passive margin in the south). Carnian crustal extension led to subsidence of the Variscan/Cimmerian chain, most parts of which merged below sea level. This is the reason why 90% of the detritus of the Carnian Tyros Beds are not related to the Variscan, but to the Cadomian and Grenvillian basement of the E-Gondwana derived Cimmerian ribbon continent

End-of-life decisions in acute stroke patients: an observational cohort study

Background: Crucial issues of modern stroke care include best practice end-of-life-decision (EOLD)-making procedures and the provision of high-quality palliative care for dying stroke patients. Methods: We retrospectively analyzed records of those patients who died over a 4-year period (2011–2014) on our Stroke Unit concerning EOLD, focusing on the factors that most probably guided decisions to induce limitation of life-sustaining therapy and subsequently end-of-life-care procedures thereafter. Results: Of all patients treated at our Stroke Unit, 120 (2.71 %) died. In 101 (86.3 %), a do-not-resuscitate-order (DNRO) was made during early treatment. A decision to withdraw/withhold further life supportive therapy was made in 40 patients (34.2 %) after a mean of 5.0 days (range 0–29). Overall patient death occurred after a mean time of 7.0 days (range 1–30) and 2.6 days after therapy restrictions. Disturbance of consciousness at presentation, dysphagia on day 1 and large supratentorial stroke were possible indicators of decisions to therapeutic withdrawing/withholding. Proceedings of EOL care in these patients were heterogeneous; in most cases monitoring (95 %), medical procedures (90 %), oral medication (88 %), parenteral nutrition (98 %) and antibiotic therapy (86 %) were either not ordered or withdrawn, however IV fluids were continued in all patients. Conclusions: A high percentage of stroke patients were rated as terminally ill and died in the course of caregiving. Disturbance of consciousness at presentation, dysphagia on day 1 and large supratentorial stroke facilitated decisions to change therapeutic goals thus initiating end-of-life-care. However, there is further need to foster research on this field in order to ameliorate outcome prognostication, to understand the dynamics of EOLD-making procedures and to educate staff to provide high-quality patient-centred palliative care in stroke medicine

R-matrix Floquet theory for laser-assisted electron-atom scattering

A new version of the R-matrix Floquet theory for laser-assisted electron-atom scattering is presented. The theory is non-perturbative and applicable to a non-relativistic many-electron atom or ion in a homogeneous linearly polarized field. It is based on the use of channel functions built from field-dressed target states, which greatly simplifies the general formalism.Comment: 18 pages, LaTeX2e, submitted to J.Phys.