Thyroid disturbances after COVID-19 and the effect of vaccination in children: a prospective tri-center registry analysis.

Rapidly evolving clinical data suggest that the novel coronavirus (SARS-CoV-2) and vaccination against COVID-19 might be associated with thyroid disturbances. However, studies remain limited among the pediatric population. Our aim was to assess the prevalence and permanence of thyroid autoimmunity (TA) and dysfunction in children after an acute infection and its potential association with vaccination. A prospective, multicenter registry analysis was performed among 458 children (mean age: 12.4 ± 3,8 years, 45.4% male) with preceding COVID-19. Patient inclusion lasted from 24th March, 2021 to 23rd March, 2022 at three pediatric outpatient facilities at Semmelweis University, Budapest. Primary outcomes were the rate of thyroid disturbances assessed by laboratory parameters (thyroid function tests, antithyroglobulin [ATG] and anti-thyroid peroxidase [ATPO] antibodies) and thyroid ultrasound. TA rate among vaccinated and unvaccinated children was determined. Children with newly diagnosed thyroid alterations were followed up for 12.7 ± 4.3 months. Six children had previous thyroid disease. Out of 452 children, 30 cases (6.6%) of newly diagnosed TA (six of them had abnormal thyroid-stimulating hormone [TSH] levels) and eight cases (1.8%) of isolated TSH elevation were observed. Ultrasound-proven autoimmune thyroiditis (AIT) was 4.0%. No association was found between COVID-19 vaccination and thyroid autoimmunity (χ2(1,N = 452) = 0.138, p = 0.815). Among children with TA, 73.3% had long-lasting alterations.  Conclusion: Vaccination had no effect on the prevalence of TA. Until further controlled studies state otherwise, children with preceding COVID-19 might benefit from thyroid screening. What is Known: • Numerous case reports implicate that coronavirus disease-2019 (COVID-19) and vaccination against SARS-CoV-2 can be responsible for thyroid disturbances. • Thyroid alterations discovered during acute COVID-19 tend to cease by time and only incidental thyroid autoimmunity (TA) is diagnosed after COVID-19. In adults, no increase in vaccine-related hyper- or hypothyroidism was found. What is New: • TA rate after COVID-19 vaccination among children was not increased. TA had no role in long COVID syndrome. • We discovered a considerable rate of TA (6.6%) and ultrasound-proven autoimmune thyroiditis (AIT) (4.0%) after SARS-CoV-2 infection, and the majority of these alterations remained positive after 6 months.

Plasma progesterone, metabolic hormones and beta-hydroxybutyrate in Holstein-Friesian cows after superovulation.

Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL.

The effect of internal and external factors on bovine embryo transfer results in a tropical environment.

The objectives of this work were to determine the effect of external (synchronization methods, month, embryo origin and farm effects) and internal factors (age and size of CL, embryo development and quality score, synchronization methods, age of recipient, quality of transfer and reuse of recipients) on a commercial embryo transfer program in a tropical environment. In the program 1466 Holstein-Friesian purchased embryos were implanted to zebu/European crossbred recipients under field conditions. There were 502 pregnancies detected in this large-scale extension programme. Synchronization methods, month, embryo origin, and farm effects were found to have affected the success rate of embryo transfer. Due to the hot climate and large distances between recipient farms, seasonal effects, reused recipient pregnancy results and the effect of embryo development stage differed from previously reported results. Investigation by ultrasonograph showed that embryo loss occurred before 35 days of pregnancy. Under field conditions, routine fetal sexing resulted in <5% misidentification. In conclusion, under tropical conditions external factors have a major influence on the results of pregnancy from embryo transfer.

Progesterone profiles and oestrous cycle changes following superovulatory treatment of Holstein-Friesian dairy cows in a tropical environment.

Changes of progesterone (P4) profiles and oestrous cycle were investigated up to 70 days in 20 superovulated Holstein-Friesian cows in a dry tropical environment (Brazil). Superovulated cows showed no significant differences in relation to P4 level at the time of embryo recovery (39.0 +/- 27.1 nmol/L, P = 0.536), first and second (12.0 +/- 6.0 and 10.7 +/- 2.2 nmol/L, P = 0.543) cycle. There was a close correlation between serum P4 concentration and the number of corpora lutea (CL; 13.3 +/- 9.5) at the recovery (P < 0.0001). After the embryo collection, cows returned to cycle in different ways: (i) group of donors returning to cycle after 2.2 +/- 0.8 days, (ii) group with a delay of 11.0 +/- 1.9 days; and (iii) animals having a long (28.8 +/- 2.2 days) acyclic period, which is significant (P < 0.001). The remaining animals (30%) showed cystic ovarian malformations. P4 level at the time of embryo recovery does not influence the oestrous cycle changes. The results suggest that Holstein-Friesian donor cows may suffer from cystic ovarian degeneration and may have a long acyclic period after superovulatory treatment in a tropical climate.