Using a combination of anterograde and retrograde neuronal tract-tracing techniques, the descending projections from the paraventricular nucleus of the hypothalamus (PVN) to the brain/spinal cord and in particular those axonal projections that appear to be contiguous with sympathetic preganglionic neurones (SPN) projecting to the stellate ganglion have been studied. Descending PVN pathways were located by the anterograde transport of biotinylated dextran amine (BDA), whilst SPN were retrogradely labelled with cholera B toxin subunit conjugated to horseradish peroxidase (CB-HRP). BDA-labelled PVN axons terminated in both hypothalamic and extrahypothalamic (including the midbrain, medulla and spinal cord) brain nuclei, with dense terminal labelling observed particularly in the arcuate hypothalamic nucleus and adjacent median eminence, in the solitary tract, vagal nuclei and in the intermediolateral region of the spinal cord (IML). Varicose descending PVN fibres in the IML were often observed to closely appose both the cell soma and dendrites of retrogradely labelled SPN (projecting to the stellate ganglion) in the spinal cord. In addition, it was shown that PVN descending axons crossing to the contralateral side of the spinal cord were closely associated with retrogradely labelled SPN projecting to the superior cervical ganglion. Such findings suggest that descending pathways from the PVN may exhibit a direct influence on cardiac sympathetic outflow and may also influence the behaviour of the contralateral population of SPN projecting to the superior cervical ganglion.
A recent study using transsynaptically transported pseudorabies virus, injected into the adrenal gland, showed labelled neurones in the paraventricular nucleus (PVN) of the hypothalamus, indicating that these neurones send projections to sympathoadrenal preganglionic neurones (SPNs). However, this technique cannot conclusively demonstrate that the pathway is monosynaptic. In order to investigate the possibility of a direct projection from the PVN to SPNs, the present study used the anterograde tracer biotin dextran amine to label paraventricular spinal projections and the retrograde tracer cholera toxin B conjugated to horseradish peroxidase to label SPNs. In addition, because electrophysiological evidence suggests vasopressin to be a neurotransmitter candidate in this pathway, immunocytochemical identification of the peptide and retrograde labelling of SPNs to the adrenal medulla were used to investigate this. The results of these studies show spinally projecting paraventricular axons with terminal varicosities closely associated with SPNs. Therefore some of these associations may represent boutons forming synaptic contact on SPNs. Similarly, vasopressin fibres were found close to the dendrites and soma of SPNs. It is suggested that spinal axons originating from paraventricular neurones can provide a direct influence on adrenal medullary function, that vasopressin is a possible neurotransmitter involved in some of these connections and this is one means by which the paraventricular nucleus can generate a defence to stressful stimuli.
The prevalence rate of those overweight, as well as obesity among children in Saudi Arabia, keeps rising. The aim of the study was to estimate childhood obesity in the Eastern Province, Saudi Arabia.Over the period 2016 to 2017, a cross-sectional campaign was carried out in the Eastern Province of Saudi Arabia. Data were collected from over 20,000 boys' and girls' schools. The campaign collected data on birthday/age, weight, height, sex, district in which the school is located, level of education, and blood pressure level.The findings from the present study indicated a prevalence of 25.7% for overweight and obesity among high school-age students. More importantly, ≈35% of the study's students have either elevated blood pressure or hypertension. The significant predictors of childhood obesity were education level, age, glucose level, and blood pressure.The children in higher school levels originally from the Eastern Province had a high prevalence of overweight and obesity. Recommendations are made on the need of regular screening program among school-age children, as well as to continue raising awareness about childhood obesity.Abbreviations: BMI = body mass index, IQR = interquartile range.
A body of literature supports the postulation that a persistent lipid metabolic imbalance causes lipotoxicity, “an abnormal fat storage in the peripheral organs”. Hence, lipotoxicity could somewhat explain the process of sarcopenia, an aging-related, gradual, and involuntary decline in skeletal muscle strength and mass associated with several health complications. This review focuses on the recent mechanisms underlying lipotoxicity-related sarcopenia. A vicious cycle occurs between sarcopenia and ectopic fat storage via a complex interplay of mitochondrial dysfunction, pro-inflammatory cytokine production, oxidative stress, collagen deposition, extracellular matrix remodeling, and life habits. The repercussions of lipotoxicity exacerbation of sarcopenia can include increased disability, morbidity, and mortality. This suggests that appropriate lipotoxicity management should be considered the primary target for the prevention and/or treatment of chronic musculoskeletal and other aging-related disorders. Further advanced research is needed to understand the molecular details of lipotoxicity and its consequences for sarcopenia and sarcopenia-related comorbidities.
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