Effects of Systemic Hyperoxia on Eustachian Tube Ventilatory Function

Middle ear negative pressure and effusions, decreased middle ear compliance, and abnormal tympanometry results have been described after diving on oxygen. Middle ear gas hyperoxia has been shown to down-regulate the eustachian tube ventilatory function (ETVF). The purpose of the present study was to investigate to what extent systemic hyperoxia in the face of air-equivalent middle ear gas composition might interfere with the ETVF. ETVF was investigated in four young adult female cynomolgus monkeys by the forced-response and inflation-deflation tests using air while the animals breathed either room air or 100% normobaric oxygen. Higher opening, closing, and steady-state pressures were observed under systemic hyperoxia. The percentage of the applied pressure equalized, and the maximal pressure change on a single swallow in the deflation test were both lower under hyperoxic conditions. The results show that systemic hyperoxia might impair ETVF. This observation adds to our understanding of the pathophysiology of middle ear dysfunction observed after diving on oxygen.     

The effect of intensive care on in-hospital survival

Intensive Care Units (ICU) are one of the most powerful and expensive technologies within inpatient care. However, its effect on survival is still an issue under discussion. The objective of this paper is to assess the effect of General ICU on in-hospital survival. We assessed the effect of ICU on survival using Linear and Probit regressions. Since admission to IC is not random and depends on unobserved (to the researcher) heterogeneity, we reassessed the IC effect by Instrumental Variables (IV) and Bivariate Probit techniques, using crowding in the IC unit as an instrument. The results show that a simple Probit of the IC effect on survival is 7–10 percentage-points (pts). The IV estimate of the IC effect on survival is 21–34 pts, and the Bivariate Probit estimate is 17–21 pts. We conclude that although admitted patients are at lower risk of death, as determined by their observable (to the researcher) characteristics, controlling for observable differences, those with a higher unobserved risk of mortality are more likely to be admitted. The implications for an optimal admission policy are discussed.     

Neoplastic diseases of the head & neck in children

Pediatric neoplasm is next only to trauma as the most common cause of death. The cervicofacial malignancies presents a unique challenge owing to potential adverse effects of both the disease process and the treatment employed on critical developing head and neck structures. This study comprised of 106 children below 12 years age group conducted during 1999–2003 at JNMC, Aligarh. Of 106 cases 70 were benign neoplasms and 36 malignant neoplasms. Nasopharynx was the commonest site of involvement. Nasopharyngeal angiofibroma was the commonest benign tumour and lymphoma was the commonest malignant neoplasm. Team approach is required for mitigation of the disease process.     

Potentiation of tumor response to radiation or chemoradiation by selective cyclooxygenase-2 enzyme inhibitors

Cyclooxygenase-2 (COX-2) is an enzyme expressed primarily in pathologic states, such as inflammatory disorders and cancer, where it mediates prostaglandin production. Its overexpression is associated with more aggressive biologic tumor behavior and adverse patient outcome. Increasing evidence shows that agents that selectively inhibit COX-2 enhance tumor response to radiation or chemotherapeutic agents. This article gives an overview of some of this evidence. In addition, we describe new results showing that celecoxib, a selective COX-2 inhibitor, enhanced response of A431 human tumor xenografts in nude mice to radiation by an enhancement factor (EF) of 1.43 and to the chemotherapeutic agent docetaxel by an EF of 2.07. Celecoxib also enhanced tumor response when added to the combined docetaxel plus radiation treatment (EF = 2.13). Further experiments showed that selective COX-2 inhibitors enhanced tumor cell sensitivity to ionizing radiation, involving inhibition of cellular repair from radiation damage and cell cycle redistribution as mechanisms for some cell types. The results show that selective COX-2 inhibitors have the potential to improve tumor radiotherapy or radiochemotherapy, and this therapeutic strategy is currently under clinical testing.     

Spontaneous xenogeneic GvHD in Wilms' tumor Patient‐Derived xenograft models and potential solutions

Severely immunocompromised NOD.Cg‐Prkdc ^scid Il2rg ^tm1Sug (NOG) mice are among the ideal animal recipients for generation of human cancer models. Transplantation of human solid tumors having abundant tumor‐infiltrating lymphocytes (TILs) can induce xenogeneic graft‐versus‐host disease (xGvHD) following engraftment and expansion of the TILs inside the animal body. Wilms'' tumor (WT) has not been recognized as a lymphocyte‐predominant tumor. However, 3 consecutive generations of NOG mice bearing WT patient‐derived xenografts (PDX) xenotransplanted from a single donor showed different degrees of inflammatory symptoms after transplantation before any therapeutic intervention. In the initial generation, dermatitis, auto‐amputation of digits, weight loss, lymphadenopathy, hepatitis, and interstitial pneumonitis were observed. Despite antibiotic treatment, no response was noticed, and thus the animals were prematurely euthanized (day 47 posttransplantation). Laboratory and histopathologic evaluations revealed lymphoid infiltrates positively immunostained with anti‐human CD3 and CD8 antibodies in the xenografts and primary tumor, whereas no microbial infection or lymphoproliferative disorder was found. Mice of the next generation that lived longer (91 days) developed sclerotic skin changes and more severe pneumonitis. Cutaneous symptoms were milder in the last generation. The xenografts of the last 2 generations also contained TILs, and lacked lymphoproliferative transformation. The systemic immunoinflammatory syndrome in the absence of microbial infection and posttransplant lymphoproliferative disorder was suggestive of xGvHD. While there are few reports of xGvHD in severely immunodeficient mice xenotransplanted from lymphodominant tumor xenografts, this report for the first time documented serial xGvHD in consecutive passages of WT PDX‐bearing models and discussed potential solutions to prevent such an undesired complication.     

Effect of Sleeper-Ballast Particle Contact on Lateral Resistance of Concrete Sleepers in Ballasted Railway Tracks

Although a sleeper makes a great contribution to the lateral resistance of ballasted tracks, in this regard, limited studies have been carried out on the effect of its contact surface with ballast aggregates. The current paper is dedicated to evaluating the effect of sleeper shape on the lateral resistance of ballasted track through discrete element modelling (DEM). For this purpose, firstly, a DEM model was validated based on the experimental results. Then, a sensitivity analysis was undertaken on the effect of the different contact areas that a standard concrete sleeper faces with the crib, shoulder and underlying ballast aggregates on lateral resistance of a single sleeper. As the main result of the current study, a high accurate regression equation for constant weight 319.2 kg and constant density 2500 kg/m³ of the sleepers was fitted between different sleeper contact areas and the maximum lateral resistance of a concrete sleeper for 3.5 mm lateral displacement in ballasted railway tracks. The obtained results showed that the effect of the sleeper’s head area compared to the underlying area of the sleeper and the head area of the sleeper compared to the sleeper’s side area in terms of lateral resistance are 8.2 times and 14.5 times more, respectively.     

An Overview of the Stability and Fretting Corrosion of Microgrooved Necks in the Taper Junction of Hip Implants

Fretting corrosion at the head–neck interface of modular hip implants, scientifically termed trunnionosis/taperosis, may cause regional inflammation, metallosis, and adverse local tissue reactions. The severity of such a deleterious process depends on various design parameters. In this review, the influence of surface topography (in some cases, called microgrooves/ridges) on the overall performance of the microgrooved head–neck junctions is investigated. The methodologies together with the assumptions and simplifications, as well as the findings from both the experimental observations (retrieval and in vitro) and the numerical approaches used in previous studies, are presented and discussed. The performance of the microgrooved junctions is compared to those with a smooth surface finish in two main categories: stability and integrity; wear, corrosion, and material loss. Existing contradictions and disagreements among the reported results are reported and discussed in order to present a comprehensive picture of the microgrooved junctions. The current research needs and possible future research directions on the microgrooved junctions are also identified and presented.     

Interspecies Recombination-Led Speciation of a Novel Geminivirus in Pakistan

Recombination between isolates of different virus species has been known to be one of the sources of speciation. Weeds serve as mixing vessels for begomoviruses, infecting a wide range of economically important plants, thereby facilitating recombination. Chenopodium album is an economically important weed spread worldwide. Here, we present the molecular characterization of a novel recombinant begomovirus identified from C. album in Lahore, Pakistan. The complete DNA- A genome of the virus associated with the leaf distortion occurred in the infected C. album plants was cloned and sequenced. DNA sequence analysis showed that the nucleotide sequence of the virus shared 93% identity with those of the rose leaf curl virus and the duranta leaf curl virus. Interestingly, this newly identified virus is composed of open reading frames (ORFs) from different origins. Phylogenetic networks and complementary recombination detection methods revealed extensive recombination among the sequences. The infectious clone of the newly detected virus was found to be fully infectious in C. album and Nicotiana benthamiana as the viral DNA was successfully reconstituted from systemically infected tissues of inoculated plants, thus fulfilling Koch’s postulates. Our study reveals a new speciation of an emergent ssDNA plant virus associated with C. album through recombination and therefore, proposed the tentative name ‘Chenopodium leaf distortion virus’ (CLDV).     

The Impact of Job-Demand-Control-Support on Leptin and Ghrelin as Biomarkers of Stress in Emergency Healthcare Workers

Despite the available literature on the consequences of night shiftwork on stress and food intake, its impact on leptin and ghrelin has never been studied. We previously demonstrated that leptin and ghrelin were biomarkers related to stress, and acute stress-induced a decrease in leptin levels and an increase in ghrelin levels. We performed a prospective observational study to assess the influence of night work, nutrition, and stress on the levels of ghrelin and leptin among emergency healthcare workers (HCWs). We took salivary samples at the beginning of a day shift and/or at the end of a night shift. We also monitored stress using the job demand-control-support model of Karasek. We recorded 24-h food intake during the day shift and the consecutive night shift and during night work and the day before. We included 161 emergency HCWs. Emergency HCWs had a tendency for decreased levels of leptin following the night shift compared to before the dayshift (p = 0.067). Furthermore, the main factors explaining the decrease in leptin levels were an increase in job-demand (coefficient −54.1, 95 CI −99.0 to −0.92) and a decrease in job control (−24.9, −49.5 to −0.29). Despite no significant changes in ghrelin levels between shifts, social support was the main factor explaining the increase in ghrelin (6.12, 0.74 to 11.5). Food intake (kcal) also had a negative impact on leptin levels, in addition to age. Ghrelin levels also decreased with body mass index, while age had the opposite effect. In conclusion, we confirmed that ghrelin and leptin as biomarkers of stress were directly linked to the job demand-control-support model of Karasek, when the main cofounders were considered.