Spontaneous interneuron activity plays a critical role in developing neuronal networks. Discharges conducted antidromically along the dorsal root (DR) precede those from the ventral root’s (VR) motoneurons. This work studied whether spinal interneurons project axons into the neonate’s dorsal roots. Experiments were carried out in postnatal Swiss-Webster mice. We utilized a staining technique and found that interneurons in the spinal cord’s dorsal horn send axons through the dorsal roots. In vitro electrophysiological recordings showed antidromic action potentials (dorsal root reflex; DRR) produced by depolarizing the primary afferent terminals. These reflexes appeared by stimulating the adjacent dorsal roots. We found that bicuculline reduced the DRR evoked by L5 dorsal root stimulation when recording from the L4 dorsal root. Simultaneously, the monosynaptic reflex (MR) in the L5 ventral root was not affected; nevertheless, a long-lasting after-discharge appeared. The addition of 2-amino-5 phosphonovaleric acid (AP5), an NMDA receptor antagonist, abolished the MR without changing the after-discharge. The absence of DRR and MR facilitated single action potentials in the dorsal and ventral roots that persisted even in low Ca2+ concentrations. The results suggest that firing interneurons could send their axons through the dorsal roots. These interneurons could activate motoneurons producing individual spikes recorded in the ventral roots. Identifying these interneurons and the persistence of their neuronal connectivity in adulthood remains to be established.

BACKGROUND: Thyroid dysfunction is associated with negative neonatal and obstetric outcomes. Large differences in thyroid function reference intervals exist across different populations. These differences can be explained by population-specific factors, such as iodine status. Many countries in Latin America report iodine sufficiency, but relatively few countries have published up-to-date data on iodine levels and thyroid function in the overall population, and especially in pregnant women. We evaluated the iodine status of pregnant women in Chile and determined thyroid hormone reference ranges in this population. METHODS: This was a prospective observational study of healthy Chilean women at their first prenatal visit before week 14. Thyroid-stimulating hormone (TSH), total thyroxine (T4), free T4, antithyroid peroxidase antibody (TPOAb), and iodine levels from spot urine samples were measured. Iodine status and the reference ranges for TSH were calculated. RESULTS: A total of 1,022 pregnant women in the first trimester were selected. Urinary iodine levels were measured in 302 randomly-selected women. The median urinary iodine concentration was 173.45 µg/L (interquartile range, 108.11 to 249.35).The reference ranges of TSH were calculated in 670 patients selected according to the National Academy of Clinical Biochemistry guidelines. The median TSH level was 1.88 µIU/mL (2.5th percentile: 0.13 to 97.5th percentile: 5.37). Using the reference range in the 1,022 women, the prevalence of clinical hypothyroidism was 1.76%, and that of subclinical hypothyroidism was 3.92%. TPOAb positivity was more common in women with TSH levels above 3.5 µIU/mL. CONCLUSION: We found adequate iodine intake and a right-shifted distribution of serum TSH levels in pregnant women in Chile. The prevalence of hypothyroidism in our sample of pregnant women was higher than has been described in the literature.
Biochemistry ; Chile ; Female ; Humans ; Hypothyroidism ; Iodine ; Latin America ; Observational Study ; Peroxidase ; Pregnancy ; Pregnancy Trimester, First* ; Pregnancy* ; Pregnant Women ; Prevalence ; Prospective Studies ; Reference Values* ; Thyroid Gland ; Thyrotropin* ; Thyroxine

Objectives: This study aims to assess the effect of ultralow dose 0.005% estriol vaginal gel in women with genitourinary syndrome of menopause (GSM). Methods: In this prospective and multicenter single-arm study, efficacy was assessed by the evaluation of the epithelial maturation value (MV), vaginal pH, symptoms and signs of vulvovaginal atrophy. Tolerability, acceptability, and the effect on intimate relationships were also evaluated. Results: We included 35 postmenopausal women with moderate-to-severe vaginal dryness. The most bothering symptom reported was vaginal dryness. The mean increase in the MV after 7 and 14 days of treatment were 22.1 (P < 0.001) and 39.9 (P < 0.001) points, with an increase in the superficial cells of 17.7 percentage points (pp) (95% confidence interval [CI], 7.9–27.4; P < 0.001) and 41.4 pp (95% CI, 28.2–54.6; P < 0.001) observed at the timepoints. Additionally, the pH decreased by 0.6 ± 0.7 (mean ± SD) at 7 days (P < 0.0001) and by 1.1 ± 0.8 at 14 days (P < 0.0001) from a baseline mean value of 6.3 ± 0.8. The severity of vaginal dryness (range, 0 [none] to 3 [severe]) was significantly reduced by a mean of 1.4 points (P < 0.0001) at 7 days and 2 points (P < 0.0001) at 14 days. Conclusions Ultralow dose 0.005% estriol vaginal gel produced a rapid improvement of most relevant symptoms and signs of GSM. This clinically meaningful response was observed from the initial days of treatment, confirming a fast onset and a progressive action.

The mechanism is unclear for the reported protective effect of hyperbaric oxygen preconditioning against oxidative stress in tissues, and the distinct effects of hyperbaric oxygen applied after stress. The trained mice were divided into three groups: the control, hyperbaric oxygenation preconditioning, and hyperbaric oxygenation applied after mild (fasting) or hard (prolonged exercise) stress. After preconditioning, we observed a decrease in basal levels of nitric oxide, tetrahydrobiopterin, and catalase despite the drastic increase in inducible and endothelial nitric oxide synthases. Moreover, the basal levels of glutathione, related enzymes, and nitrosative stress only increased in the preconditioning group. The control and preconditioning groups showed a similar mild stress response of the endothelial and neuronal nitric oxide synthases. At the same time, the activity of all nitric oxide synthase, glutathione (GSH) in muscle, declined in the experimental groups but increased in control during hard stress. The results suggested that hyperbaric oxygen preconditioning provoked uncoupling of nitric oxide synthases and the elevated levels of GSH in muscle during this study, while hyperbaric oxygen applied after stress showed a lower level of GSH but higher recovery post-exercise levels in the majority of antioxidant enzymes. We discuss the possible mechanisms of the redox response and the role of the nitric oxide in this process.