Search results for "DOP"
showing 10 items of 4870 documents
Circadian rhythm and effects of light on cAMP content of the dwarf hamster suprachiasmatic nucleus
1998
The present study was conducted in the dwarf hamster (Phodopus sungorus) to investigate whether a circadian rhythm is present in the content of the second messenger cyclic adenosine 3',5'-monophosphate (cAMP) in the suprachiasmatic nucleus (SCN), the endogenous clock in mammals. In animals held under light/dark conditions (LD), we observed high levels at the end of the light phase and low levels during the night in frozen SCN punches. In animals held in continuous dark, a similar rhythm was seen although a second peak was present in the subjective day. In senile hamsters under LD, the decrease of cAMP levels at the light transition was not seen. These data, obtained for the first time from …
Pituitary resistance to thyroid hormone action with preserved circadian rhythm of thyrotropin in a postmenopausal woman.
1992
We assessed the 24-h behavior of circulating TSH and the dopaminergic control on TSH release in a postmenopausal woman, who had elevated levels of serum thyroid hormones and an inappropriately high concentration of serum TSH, indicating pituitary resistance to thyroid hormone action. The patient was found to have a daily profile of serum TSH similar to that of normal subjects, except for the persistently elevated 24 h levels, suggesting that alterations in thyroid hormone negative feedback control did not affect substantially circadian TSH rhythm. The acute administration of a dopamine antagonist drug (metoclopramide) resulted in a markedly elevated peak of serum TSH, similar both in the mo…
HGH secretion after oral application of l-Dopa and l-Carbiodopa
1976
The stimulatory effect of L-Dopa and L-Carbidopa (Nacom) on HGH secretion was determined in 12 children of normal height aged from 6 to 14 years. Each child received a standard dose of 250 mg L-Dopa and 25 mg L-Carbidopa p.o. HGH concentration in the serum was determined at standard intervals. All subjects showed a sufficient increase of HGH. The mean value was 19.6 ng/ml. According to the maximum values of the HGH concentration the sample can be divided into two groups; the first group reached the highest values after 20--40 min, the second one after 60--90 min. On evaluation of the curve of the mean values it appears that 2 blood samples taken 40 and 90 min after the ingestion of L-Dopa a…
Simultaneous stimulation of growth hormone, adrenocorticotropin and cortisol with L‐dopa/L‐carbidopa and propranolol in children of short stature
2000
In 59 otherwise healthy children of short stature, the simultaneous response of growth hormone, cortisol and plasma adrenocorticotropin (ACTH) to L-dopa/L-carbidopa and propranolol at 45 and 90 min after administration were investigated. A growth hormone response of 10 microg/l or higher was considered positive. The definition of a positive cortisol response included either a hormone increase of at least 193 nmol/l or a peak hormone level of at least 497 nmol/l. The ACTH increase had to be fourfold above 11 pmol/l to be considered positive. In the 59 investigated children, the median basal growth hormone levels increased from 1.35 microg/l to 18.05 microg/l and 10.15 microg/l at 45 and 90 m…
Clinical and metabolic findings in a 6-year-old boy with a Leydig cell tumour
2011
Aim: To analyse the urinary steroid metabolome in a boy who had true precocious puberty after a Leydig cell tumour. Method: Case report and detailed description of clinical and metabolic findings in a 7-year-old-boy with a Leydig cell tumour. Results: Before surgery, the urinary steroid metabolome showed an activation of an alternative route to gonadal androgens independent of dehydroepiandrosterone (DHEA). After surgery, the boy entered true precocious puberty. Under leuprolide acetate treatment, clinical and laboratory findings normalized. Conclusion: Central precocious puberty after precocious pseudopuberty may be more common than expected and should be considered in children with pe…
Idiosyncratic responses to simulated herbivory by root fungal symbionts in a subarctic meadow
2021
Plant-associated fungi have elementary roles in ecosystem productivity. There is little information on the interactions between arbuscular mycorrhizal (AM) fungal symbiosis, fine endophytic (FE) and dark septate endophytic (DSE) fungi, and their host plants in cold climate systems. In particular, the environmental filters potentially driving the relative abundance of these root symbionts remain unknown. We investigated the interlinkage of plant and belowground fungal responses to simulated herbivory (clipping, fertilization, and trampling) in a subarctic meadow system. AM and FE frequency in the two target plant roots, Potentilla crantzii and Saussurea alpina, was unaffected by simulated he…
Toward Comprehensive Plant Microbiome Research
2020
Microbes have driven eco-evolutionary adaptations organizing biodiversity from the origin of life. They are ubiquitous and abundant, facilitating the biochemical processes that make Earth habitable and shape ecosystem structures, functions, and services. Recent studies reveal that commensalistic and beneficial microbes associated with wild and domesticated plants may aid in establishing sustainable agriculture for a changing climate. However, developing microbe-based biotechnologies and ecosystem services requires a thorough understanding of the diversity and complexity of microbial interactions with each other and with higher organisms. We discuss the hot and blind spots in contemporary re…
Glyphosate-based herbicide use affects individual microbial taxa in strawberry endosphere but not the microbial community composition
2023
AbstractAimsIn a field study, the effects of treatments of glyphosate-based herbicides (GBHs) in soil, alone and in combination with phosphate fertilizer, were examined on the performance and endophytic microbiota of garden strawberry.Methods and resultsThe root and leaf endophytic microbiota of garden strawberries grown in GBH-treated and untreated soil, with and without phosphate fertilizer, were analyzed. Next, bioinformatics analysis on the type of 5-enolpyruvylshikimate-3-phosphate synthase enzyme was conducted to assess the potential sensitivity of strawberry-associated bacteria and fungi to glyphosate, and to compare the results with field observations. GBH treatments altered the abu…
Heritable Epichloë symbiosis shapes fungal but not bacterial communities of plant leaves
2019
Keystone microbial species have driven eco-evolutionary processes since the origin of life. However, due to our inability to detect the majority of microbiota, members of diverse microbial communities of fungi, bacteria and viruses have largely been ignored as keystone species in past literature. Here we tested whether heritable Epichloë species of pooidae grasses modulate microbiota of their shared host plant. peerReviewed
Tissue-Specific Dynamics in the Endophytic Bacterial Communities in Arctic Pioneer Plant
2020
The rapid developments in the next-generation sequencing methods in the recent years have provided a wealth of information on the community structures and functions of endophytic bacteria. However, the assembly processes of these communities in different plant tissues are still currently poorly understood, especially in wild plants in natural settings. The aim of this study was to compare the composition of endophytic bacterial communities in leaves and roots of arcto-alpine pioneer plant Oxyria digyna, and investigate, how plant tissue (leaf or root) or plant origin affect the community assembly. To address this, we planted micropropagated O. digyna plants with low bacterial load (bait pla…