Distribution of heterochromatin and rDNA on the holocentric chromosomes of the aphids Dysaphis plantaginea and Melanaphis pyraria (Hemiptera: Aphididae)

The structure of the holocentric chromosomes of the rosy apple aphid, Dysaphis plantaginea (2n = 12), and pear-grassaphid, Melanaphis pyraria (2n = 8), was studied using C-banding, NOR, Giemsa and fluorochrome staining, and fluorescent in situhybridization (FISH). Contrary to the equilocal distribution of heterochromatin typical of monocentric chromosomes, in both species C-banding evidenced a tendency of highly repetitive DNAs to be restricted to the X chromosomes. Silver staining and FISH, using a 28S rDNA probe, located rDNA genes on one telomere of each X chromosome, the only brightly fluorescent C-positive sites revealed by CMA3 staining, whereas all other heterochromatic C-bands were DAPI positive. Both species showed a noticeable amount of rDNA heteromorphism. Mitotic recombination is proposed as a possible mechanism responsible for the variation in size of rDNA

X-linked heterochromatin distribution in the holocentric chromosomes of the green apple aphid Aphis pomi

Chromatin organization in the holocentric chromosomes of the green apple aphid Aphis pomi has been investigated at a cytological level after C-banding, NOR, Giemsa, fluorochrome staining and fluorescent in situ hybridization (FISH). C-banding technique showed that heterochromatic bands are exclusively located on X chromosomes. This data represents a peculiar feature that clearly contradicts the equilocal distribution of heterochromatin typical of monocentric chromosomes. Moreover, silver staining and FISH carried out with a 28S rDNA probe localized rDNA genes on one telomere of each X chromosome; CMA(3) staining reveals that these silver positive telomeres are, the only GC-rich regions among A. pomi heterochromatin, whereas all other C-positive bands are DAPI positive thus containing AT-rich DNA

Valutazione dell’esposizione a sostanze chimiche: il ruolo del monitoraggio biologico in lavoratori esposti a TCE.

L’obiettivo di questo studio era esaminare i profili di un gruppo di lavoratori di un reparto di manutenzione di un’industria aeronautica espostio a tricloroetilene (TCE) dopo il 2001/59/ce ed il DL n. 197 06/14/2002, e di verificare l’utilità e la validità del monitoraggio biologico come fattore determinante per la sicurezza degli operatori

Risk factors associated with adverse fetal outcomes in pregnancies affected by Coronavirus disease 2019 (COVID-19): a secondary analysis of the WAPM study on COVID-19.

Objectives To evaluate the strength of association between maternal and pregnancy characteristics and the risk of adverse perinatal outcomes in pregnancies with laboratory confirmed COVID-19. Methods Secondary analysis of a multinational, cohort study on all consecutive pregnant women with laboratory-confirmed COVID-19 from February 1, 2020 to April 30, 2020 from 73 centers from 22 different countries. A confirmed case of COVID-19 was defined as a positive result on real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of nasal and pharyngeal swab specimens. The primary outcome was a composite adverse fetal outcome, defined as the presence of either abortion (pregnancy loss before 22 weeks of gestations), stillbirth (intrauterine fetal death after 22 weeks of gestation), neonatal death (death of a live-born infant within the first 28 days of life), and perinatal death (either stillbirth or neonatal death). Logistic regression analysis was performed to evaluate parameters independently associated with the primary outcome. Logistic regression was reported as odds ratio (OR) with 95% confidence interval (CI). Results Mean gestational age at diagnosis was 30.6+/-9.5 weeks, with 8.0% of women being diagnosed in the first, 22.2% in the second and 69.8% in the third trimester of pregnancy. There were six miscarriage (2.3%), six intrauterine device (IUD) (2.3) and 5 (2.0%) neonatal deaths, with an overall rate of perinatal death of 4.2% (11/265), thus resulting into 17 cases experiencing and 226 not experiencing composite adverse fetal outcome. Neither stillbirths nor neonatal deaths had congenital anomalies found at antenatal or postnatal evaluation. Furthermore, none of the cases experiencing IUD had signs of impending demise at arterial or venous Doppler. Neonatal deaths were all considered as prematurity-related adverse events. Of the 250 live-born neonates, one (0.4%) was found positive at RT-PCR pharyngeal swabs performed after delivery. The mother was tested positive during the third trimester of pregnancy. The newborn was asymptomatic and had negative RT-PCR test after 14 days of life. At logistic regression analysis, gestational age at diagnosis (OR: 0.85, 95% CI 0.8-0.9 per week increase; pPeer reviewe