Evidence indicates that repeated-bouts of eccentric exercise (EE) do not exacerbate the extent of muscle damage indices, as compared to a single-bout. We hypothesized that molecular adaptations, under repeated-bouts of EE, would include suppression of muscle repair inhibitory factors such as myostatin and up-regulation of muscle repair positive regulatory factors such as myogenic regulatory factors (MRFs). Fifteen males were recruited for this study. The exercise group (n=9) successfully completed six sets of 15 reps of maximum voluntary eccentric contractions, for six consecutive days, using a dynamometer (Multicont-II). Blood and muscle biopsy samples were obtained from each subject 1 week prior to exercise, 2 days post the first training session, and 24 h after the last training session. Gene expression levels were determined using real-time RT-PCR. Blood samples were analyzed for creatine kinase (CK) and lactate-dehydrogenase (LDH) activity. Repeated-bouts of EE induced a large down-regulation of myostatin mRNA (-73%) which persisted throughout the study. The responses of MRFs were mild. At day 3 only myogenin increased significantly (1.9 fold) while MyoD decreased by 45%. Surprisingly, at day 7, despite the presence of muscle damage indices, all MRFs returned to the pre-exercise levels. The results of the present study showed that repeated-bouts of EE, for six consecutive days, dramatically decreased Myostatin mRNA expression but impaired the expression patterns of MRFs such that, with the exception of myogenin that showed a moderate non-sustained increase, MyoD and MYf5 response was minimal.

The vitamin-D-sensitivity of the cardiovascular system may show gender differences. The prevalence of vitamin D (VD) deficiency (VDD) is high, and it alters cardiovascular function and increases the risk of stroke. Our aim was to investigate the vascular reactivity and histological changes of isolated carotid artery of female and male rats in response to different VD supplies. A total of 48 male and female Wistar rats were divided into four groups: female VD supplemented, female VDD, male VD supplemented, male VDD. The vascular function of isolated carotid artery segments was examined by wire myography. Both vitamin D deficiency and male gender resulted in increased phenylephrine-induced contraction. Acetylcholine-induced relaxation decreased in male rats independently from VD status. Inhibition of prostanoid signaling by indomethacin reduced contraction in females, but increased relaxation ability in male rats. Functional changes were accompanied by VDD and gender-specific histological alterations. Elastic fiber density was significantly decreased by VDD in female rats, but not in males. Smooth muscle actin and endothelial nitric oxide synthase levels were significantly lowered, but the thromboxane receptor was elevated in VDD males. Decreased nitrative stress was detected in both male groups independently from VD supply. The observed interactions between vitamin D deficiency and sex may play a role in the gender difference of cardiovascular risk.

The aim of our study was to identify whether vitamin-D deficiency (VDD) can alter the geometry of the coronary-resistance-artery system. Male Wistar rats were divided into vitamin-D-deficient (VD−, n = 10) and vitamin-D-supplemented (VD+, n = 8) groups. After eight weeks, branches and segments of the left-anterior-descending-coronary-artery (LAD) network were analyzed by a video-microscopy technique. Segments were divided into 50 μm-long cylindrical ring units. VDD did not increase the number of morphological abnormalities. The number of segments did not differ between the groups (VD−: 210 and VD+: 224; pooled data of 8 networks). A larger lumen area of branches was found in VD+ group, while 1–4-order branches were lengthier in the VD− group. VD− rats had less rich coronary-resistance-artery networks in terms of 50 µm-long units. (VD−: 6365 vs. VD+: 6602; pooled data of 8 networks). VD+ animals were richer in the 100–350 µm outer diameter range, and VD− animals were richer in the 400–550 µm-diameter units. In VD− rats, 150–200 and 300 µm units were almost missing at higher flow distances from the orifice. Serum vitamin-D alterations caused by dietary changes can affect the geometry of the coronary-artery network, which may contribute to vitamin-D-dependent changes in cardiovascular mortality.

Objective: Male sex and Vitamin D deficiency is associated with increased ischemic stroke risk that may be partially explained by local changes of circulatory control. Our aim was to examine the vascular reactivity and histological changes of isolated carotid artery of female and male rats in Vitamin D deficient and Vitamin D supplemented state.Design and method:Female and male Wistar rats were fed with vitamin D reduced rat chow for eight weeks. Another group received normal chow with further supplementation of vitamin D. Phenylephrine induced contraction, acetylcholine and estrogen induced relaxation of carotid arteries was examined by wire myography. Elastic fiber density was evaluated on resorcin-fuchsin stained tissue sections. Smooth muscle cell actin (SMA), thromboxane A2 receptor and endothelial nitric oxide synthase (eNOS) density and protein tyrosine nitration (NT) was measured by immunohistochemistry.Results:Both male sex and vitamin D deficiency resulted in increased phenylephrine induced contraction. Inhibition of cyclooxygenases by indomethacin increased the degree of contraction only in vitamin D supplemented females. Male gender was associated with reduced acetylcholine induced relaxation, and it was not altered by vitamin D deficiency. Indomethacin increased relaxation in male vessels. Estrogen induced relaxation was significantly reduced by vitamin D deficiency in female but not in male animals. Vitamin D deficiency resulted in reduced elastic fiber density in female, but decreased smooth muscle cell actin density in male rats. Thromboxane A2 receptor density was increased in vitamin D deficient males. NT immunohistochemistry was low in both male group, whereas eNOS was reduced in vitamin D deficient males.Conclusions: In rats male gender was associated with increased phenylephrine induced contraction and reduced acetylcholine induced relaxation of the carotid artery. Vitamin D deficiency caused increased contraction in both sexes; did not change acetylcholine induced relaxation, but reduced the estrogen induced relaxation in female arteries. These functional differences were accompanied with sex specific histological changes of the vessel. The observed sex specific properties and responses of carotid artery to vitamin D deficiency may play a role in the gender difference of cardiovascular and stroke risk.

Összefoglaló. Bevezetés: A COVID–19-pandémia kapcsán számos tanulmány vizsgálta a tünetek gyakoriságát és a járványterjedés jellemzőit gyermekkorban, kevés azonban az alapellátás adatait összefoglaló publikáció. Közleményünkben 12 házi gyermekorvosi praxis 545 SARS-CoV-2-fertőzött betegének adatait elemeztük a 2. (n = 293) és a 3. (n = 252) járványhullámban. Célkitűzés: A gyermekkori fertőzések tünettanának és epidemiológiai jellemzőinek összehasonlítása korcsoportok és járványhullámok között. Módszer: Valamennyi alapellátó praxis egységes retrospektív adatgyűjtést végzett ugyanazon paraméterek regisztrálásával. Eredmények: A 10 év alatti betegekben a láz, a nátha és a köhögés dominált (30–50%), míg a 10 év felettiekben magas arányban regisztráltunk általános tüneteket is (30–40% fejfájás, gyengeség, szaglászavar). A 2. hullámban a 11–18 évesek (68%), a 3. hullámban a 0–10 évesek (53%) voltak többségben. A 3. hullámban szignifikánsan emelkedett a légúti tünetek előfordulása, az általános tünetek gyakorisága jelentősen csökkent, és szignifikánsan nőtt a családon belüli expozíció aránya (36% vs. 58%) a 2. hullámmal összehasonlítva. A gyermekről családtagra történő továbbterjedés 24% és 16% volt a két járványhullámban, és mértékét az életkor befolyásolta. Megbeszélés: A klinikai kép az életkorral és a feltételezett vírusvariánssal mutatott összefüggést: 10 év alatt a légúti tünetek domináltak, 10 év felett szignifikánsan több általános tünetet regisztráltunk a 0–10 évesekhez képest. A 3. járványhullámban az alfa-variáns terjedésével gyakoribbá váltak a légúti tünetek, az iskolabezárások következtében megváltozott az életkori megoszlás, és megemelkedett a családi expozíció okozta fertőzések aránya. A fertőzés továbbadása háztartáson belül mindkét hullámban alacsony maradt. Következtetés: A COVID–19 klinikai megjelenését és terjedési jellemzőit jelentősen befolyásolta az érintett gyermekpopuláció életkori összetétele, a cirkuláló vírusvariáns és az aktuális korlátozó intézkedések. Orv Hetil. 2021; 162(44): 1751–1760. Summary. Introduction: During the COVID-19 pandemic, a large number of publications examined the frequency of symptoms and the mode of transmission in childhood but only a few community-based studies have been published. In our paper, 545 pediatric COVID-19 patients’ data were collected by 12 primary care pediatricians in the second (n = 293) and third (n = 252) waves of the pandemic. Objective: To compare the frequency of symptoms and household transmission in different age groups and between the two waves. Method: Patients’ data and disease characteristics were recorded retrospectively in the same manner by all participating pediatricians. Results: In patients of <10 years of age, fever, rhinorrhea and cough were registered the most frequently (30–50%), in contrast to patients of >10 years, where high frequency of general symptoms was found (30–40% headache, weakness, anosmia). In the third wave, the ratio of the age group 11–18 years declined from 68% to 47%, the frequency of respiratory symptoms increased significantly, while the ratio of general symptoms decreased. Household exposition was more frequent in the third wave (36% vs. 58%), while the transmission rate from children to family members was 24% and 16%, respectively, and it varied with age. Discussion: Clinical manifestation showed relation to age and virus variant: the older age associated with higher frequency of general symptoms and the spread of the alpha variant led to the predominance of respiratory symptoms over general complaints. Prolonged school closures affected the age distribution and increased the frequency of household exposition. Secondary household transmission remained low. Conclusion: Clinical and epidemiological characteristics of pediatric COVID-19 disease were highly influenced by age, dominant virus variant and mitigation measures. Orv Hetil. 2021; 162(44): 1751–1760.