Pulmonary hypertension in human newborns with congenital diaphragmatic hernia is associated with decreased vascular expression of nitric-oxide synthase

The molecular basis of the pathogenesis of pulmonary hypertension (PH) associated with congenital diaphragmatic hernia (CDH) is poorly understood. Variation in responses to therapeutic strategies such as nitric oxide (NO) inhalation and extracorporeal membrane oxygenation (ECMO) in patients with CDH remains a major problem in pediatric critical care. We investigated the expression pattern of NO-generating enzyme nitricoxide synthase (NOS) (both endothelial [eNOS] and inducible [iNOS] isoforms) in the lungs of CDH patients with PH and evaluated the influence of ECMO on the expression levels of these genes in an attempt to understand the underlying molecular mechanisms. Lung autopsy specimens from 23 cases of CDH not treated by ECMO and 10 ECMO-treated CDH cases were studied and compared with 11 age-matched controls. Expression of iNOS and eNOS was assessed by immunohistochemistry and video-image analysis. Expression of iNOS in the endothelium of small pulmonary arteries (external diameter≤200 μm) was significantly lower in CDH cases that had not received ECMO treatment (p=0.04). ECMO-treated CDH cases did not differ from controls in iNOS expression. Alveclar macrophages (CD68⁺ cells), of which the number also was increased, showed significantly enhanced staining for iNOS in CDH cases (p=0.03) compared with controls. The observed decrease in pulmonary expression of iNOS in patients with CDH suggests a potential role in the pathogenesis of pulmonary hypertension in newborns with CDH. ECMO treatment was correlated with induction of this enzyme, which may result in NO-mediated vasodilatation and thereby transiently reduce the pulmonary hypertension in CDH.     

Selection for early and late adult emergence alters the rate of pre-adult development in Drosophila melanogaster

Background  

Circadian clocks have been implicated in the regulation of pre-adult development of fruit flies Drosophila melanogaster. It is believed that faster clocks speed up development and slower clocks slow it down. We established three sets of D. melanogaster populations (early, control and late). The early and late populations were raised by selecting for flies that emerged either in the morning or in the evening under 12:12 hr light/dark (LD) cycles. After 75 generations of selection, the time course and waveform of the adult emergence and activity rhythms of the early and the late populations diverged from each other as well as from the controls. In this paper, we report the consequence of this selection on the rate of pre-adult development.     

Euler buckling-induced folding and rotation of red blood cells in an optical trap

We investigate the physics of an optically driven micromotor of biological origin. When a single, live red blood cell (RBC) is placed in an optical trap, the normal biconcave disc shape of the cell is observed to fold into a rod-like shape. If the trapping laser beam is circularly polarized, the folded RBC rotates. A model based on geometric considerations, using the concept of buckling instabilities, captures the folding phenomenon; the rotation of the cell is rationalized using the Poincaré sphere. Our model predicts that (i) at a critical power of the trapping laser beam the RBC shape undergoes large fluctuations, and (ii) the torque that is generated is proportional to the power of the laser beam. These predictions are verified experimentally. We suggest a possible mechanism for the emergence of birefringent properties in the RBC in the folded state.     

Neuromuscular fatigue of elbow flexor muscles of dominant and non-dominant arms in healthy humans.

The purpose of this study was to assess differences in fatigue-related changes in variables related to structures within the neuromuscular system, between the dominant and non-dominant elbow flexor muscles of right-handed individuals. Two experimental sessions were performed on the right arm and one on the left arm. For each session, maximum voluntary torque, level of voluntary activation, M-wave amplitude, twitch/train or twitch/doublet torque ratio and EMG median frequency were obtained before and up to 20 min after a sustained maximum isometric fatigue task. Our main results were: 1) reproducible fatigue-induced changes in all variables of interest between the two sessions performed with the right arm, 2) significantly greater failure in voluntary activation and neuromuscular propagation with sustained activity for the non-dominant compared with dominant side, and 3) no effect of dominance on MVC torque, endurance time, and fatigue-induced changes in EMG median frequency and elicited torques. These results suggest that the preferential use of elbow flexor muscles with the dominant arm leads to more fatigue resistance in certain structures/mechanisms of the neuromuscular system, but not in others.     

Purification of wheat germ amylase by precipitation

alpha-Amylase from various sources was found to bind alginate in free solution. The alginate-enzyme complex could be precipitated with Ca(2+). The enzyme activity could be recovered by dissolving the precipitate in 1 M maltose and precipitating alginate alone by addition of Ca(2+). Based upon these observations, alpha-amylase from wheat germ was purified with 68-fold purification and 72% recovery. The molecular weight estimated by SDS-PAGE was 18 kDa. The method also worked equally well with alpha-amylase for the whole wheat seed. The latter enzyme could be purified 54-fold with 70% activity recovery. The molecular weight of this second enzyme was estimated to be 45 kDa by SDS-PAGE.     

Radioprotective effect of rhizome extract of Zingiber montanum in Rattus norvegicus

The present study aims at determining the ability of 60% ethanol extract of the rhizome of Zingiber montanum (J. K?nig) A. Dietr. to protect bone marrow cells in vivo from radiation-induced chromosomal aberrations. Albino rats (Rattus norvegicus, 2n = 42) were used to carry out investigations on the radioprotective properties of Z. montanum. Acute toxicity of the extract was determined, and a suitable injectable dose was selected for intra-peritoneal administration. The LD(50) of the extract calculated for 72 h was 2.9 g/kg, and the calculated LD(10) dose was 1.7 g/kg. The calculated maximum tolerated dose of the rhizome extract was 1.3 g/kg. Rats were divided into 12 groups (with or without the administration of extract) and exposed to different radiation doses from 1 to 5 Gy. Whole-body irradiation of rats showed a significant dose-dependent increase in different types of chromosomal aberrations. The most common chromosomal aberrations were breaks, fragments, gaps, rings, endoreduplications and dicentric chromosomes. Ethanol extract of rhizome at a dose of 0.5 g/kg did not show any significant increase in chromosomal aberrations in unirradiated animals as compared to that of the control group. Intra-peritoneal administration of the extract at a dose of 0.5 g/kg considerably reduced the frequency of the aberrations stated above in irradiated animals with DMF value of 1.36 at 1 to 5 Gy dose range of gamma radiation. The incidence of micronucleated polychromatic erythrocytes and micronucleated normochromatic erythrocytes due to the radiation exposure was considerably reduced in extract-treated groups of animals with DMFs 1.34 and 1.17, respectively, as compared to that of the extract-untreated groups. Our results suggest that rhizome extract of Z. montanum may have a potential in protecting normal hematopoietic cells from radiation-induced damage.     

REV1 and polymerase ζ facilitate homologous recombination repair

REV1 and DNA Polymerase ζ (REV3 and REV7) play important roles in translesion DNA synthesis (TLS) in which DNA replication bypasses blocking lesions. REV1 and Polζ have also been implicated in promoting repair of DNA double-stranded breaks (DSBs). However, the mechanism by which these two TLS polymerases increase tolerance to DSBs is poorly understood. Here we demonstrate that full-length human REV1, REV3 and REV7 interact in vivo (as determined by co-immunoprecipitation studies) and together, promote homologous recombination repair. Cells lacking REV3 were hypersensitive to agents that cause DSBs including the PARP inhibitor, olaparib. REV1, REV3 or REV7-depleted cells displayed increased chromosomal aberrations, residual DSBs and sites of HR repair following exposure to ionizing radiation. Notably, cells depleted of DNA polymerase η (Polη) or the E3 ubiquitin ligase RAD18 were proficient in DSB repair following exposure to IR indicating that Polη-dependent lesion bypass or RAD18-dependent monoubiquitination of PCNA are not necessary to promote REV1 and Polζ-dependent DNA repair. Thus, the REV1/Polζ complex maintains genomic stability by directly participating in DSB repair in addition to the canonical TLS pathway.