A bibliometric analysis of primary ovarian insufficiency from 2010 to 2020.

OBJECTIVE: This study aimed to carry out a bibliometric analysis of primary ovarian insufficiency (POI) from 2010 to 2020 and to reveal the research status and hotspots in the future. METHOD: A total of 3087 articles and reviews related to POI published from 2010 to 2020 retrieved from the Web of Science Core Collection were used for bibliometric analysis. CiteSpace and VOSviewer were adopted to analyze countries and regions, organizations, authors, journals, keywords and co-cited references. RESULTS: The number of publications about POI increased year by year. The USA produced the largest number of publications and the most influence in this field. The main research directions of POI can be roughly divided into four aspects according to the analysis of keywords and co-cited references: genetic research of POI; stem cell therapy for patients with POI; prediction of ovarian function; and fertility preservation of cancer patients. Genetic research and stem cell therapy may become research hotspots in the future. CONCLUSION: This study might be the first bibliometric study to analyze publications of POI from multiple indicators, in order to provide new opinions for the research trends and possible hotspots of POI.

Expression of the RORα gene in Inner Mongolian cashmere goat hair follicles.

The expression of retinoid-acid-related orphan receptor α (RORα) was evaluated at the mRNA level using real-time polymerase chain reaction (qRT-PCR), and its expression localization was determined by in situ hybridization of adult Inner Mongolian cashmere goats at different times of the year. In situ hybridization demonstrated that RORαwas expressed in secondary hair follicles of the hair shaft, inner root sheath, outer root sheath, medulla, and other parts that are target organs of the RORαreceptor gene. qRT-PCR results showed that there was no significant difference in the RORa mRNA abundance in February, April, August, and October (P > 0.05), and the only difference occurred in December relative to February, August, and October (P < 0.05). This difference revealed that melatonin possibly promotes cashmere growth through the nuclear receptor RORα. This study provides a good foundation for future studies on the relationship between the melatonin receptor and cashmere growth; in addition, it provides new insights for increased cashmere production and quality.

Modulation of cutaneous nociceptor activity by electrical stimulation in the brain stem does not inhibit the nociceptive excitation of dorsal horn neurons.

In anesthetized cats, recordings were obtained from single lumbar dorsal horn neurons and from primary afferent fibers of the posterior tibial nerve excited by controlled noxious radiant heating of glabrous hindpaw skin. Electrical stimulation in four brain stem regions (periaqueductal gray and lateral reticular formation in the midbrain, raphe and reticular formation in the medulla) during noxious skin heating markedly reduced the nociceptive excitation of the dorsal horn neurons. In contrast, such brain stem stimulation had small and variable effects upon the noxious heat-evoked activity in the primary afferent fibers; both increases and decreases were observed. The brain stimulation also produced transient changes in blood pressure, suggesting that circulatory effects may underlie the mechanism of nociceptor modulation. It is concluded that brain stem stimulation can modulate cutaneous nociceptor activity, but that this modulatory effect on nociceptor inflow is too small and inconsistent to explain the marked descending inhibition of the nociceptive excitation of dorsal horn neurons.

Effect of intracerebroventricular injection of thyrotropin-releasing hormone on the nociceptive discharges in mesencephalic reticular formation in the rat.

Extracellular recording method was used to examine the effect of thyrotropin-releasing hormone (TRH) on 71 unit discharges of pain-excited neurons (PEN) in mesencephalic reticular formation (MRF) in 58 rats. Intracerebroventricular (icv) injection of TRH (10 micrograms/10 micrograms) produced significant decrease of pain discharge rate of PEN. TRH potentiated the inhibitory effect of electroacupuncture (EA) on nociceptive discharges when application of EA at bilateral "Zusanli" was coupled with icv injection of TRH. Both of these inhibiting effects of TRH were completely offset or strikingly decreased by icv preinjection of the cholinergic M-receptor blocker atropine. The results mentioned above and the mechanism of the inhibitory effect of TRH on pain discharges were discussed in this paper.

Inhibition of nociceptive responses of lumbar dorsal horn neurones by remote noxious afferent stimulation in the cat.

In cats anaesthetized with nitrous oxide and sodium pentobarbital, multireceptive lumbar dorsal horn neurones excited by controlled noxious radiant heating of glabrous hind paw skin were recorded by extracellular microelectrodes. These noxious heat responses were inhibited by concomitant noxious stimulation of the ipsilateral forepaw or pinna, or repetitive electrical stimulation of the ipsilateral forelimb deep radial nerve. Similar extents of inhibition were produced by noxious peripheral stimulation and by deep radial nerve stimulation in repetitive trains at intensities sufficient to excite small myelinated fibres or unmyelinated fibres. A greater inhibitory effect was produced by continuous repetitive high-intensity stimulation of the deep radial nerve. With a constant frequency (5 Hz) of continuous deep radial nerve stimulation, graded increases in stimulation intensity revealed the threshold for inhibition in the small myelinated fibre range, and an additional increment of the inhibitory effect when unmyelinated fibres were also activated. When suprathreshold for unmyelinated fibres, the efficacy of continuous deep radial nerve stimulation increased with graded increases in stimulation frequency, with a threshold frequency for inhibition between 0.5 and 1 Hz and maximal effect at 5 Hz. Two nociceptive-specific neurones studied were also inhibited by deep radial nerve stimulation. The results indicate that 'diffuse noxious inhibitory controls' (DNIC) occur in the cat and can be activated by remote electrical or natural noxious stimulation.

Spinal neuronal inhibition and EEG synchrony by electrical stimulation in subcortical forebrain regions of the cat.

In cats anaesthetized with sodium pentobarbital and 70% N2O, single lumbar dorsal horn neurons were excited by controlled noxious radiant heating of glabrous hindpaw skin. The EEG was recorded from the pericruciate cortex and posterior lateral gyrus. Subcortical forebrain sites where electrical stimulation inhibited dorsal horn neuronal heat-evoked responses contralaterally were identified by mapping the caudate nucleus, internal capsule, septum, nucleus accumbens and basal forebrain regions. Inhibitory sites were mainly located in the ventral forebrain (ventral septum, diagonal band, basal forebrain). The caudate nucleus and internal capsule had a low incidence and effectiveness of inhibitory sites. In the basal forebrain, the incidence and effectiveness of inhibitory sites decreased from caudal to rostral regions. There was a rostral limit of inhibitory sites, both medially and laterally. The magnitude of inhibition increased with graded increases in brain stimulation intensity. The mean incremental increase in inhibition was greater for caudal than for rostral basal forebrain sites. Mean stimulus currents for threshold of inhibition and for inhibition to 50% of control heat responses were lower for caudal than for rostral sites. Responses of the dorsal horn neurons to increasing temperatures of noxious skin heating were monotonic linear functions over the temperature range studied (48-53 degrees C). Stimulation in both rostral and caudal basal forebrain decreased the slope of this stimulus-response function, with a greater decrease for caudal sites. Cortical EEG synchronization was evoked by stimulation in the caudate nucleus and rostral basal forebrain. For both regions, most synchronogenic sites did not produce descending inhibition of dorsal horn neurons. The significance of these findings in relation to descending inhibition from other brain regions and stimulation-produced analgesia is discussed.