Volume XCIII, Number 15, February 22, 1974

11th International Conference of Inborn Errors of Metabolism -- AUG 29-SEP 02, 2009 -- San Diego, CAWOS: 00026894260018

Quantification of Plasma and Urine Thymidine and 2'-Deoxyuridine by LC-MS/MS for the Pharmacodynamic Evaluation of Erythrocyte Encapsulated Thymidine Phosphorylase in Patients with Mitochondrial Neurogastrointestinal Encephalomyopathy.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is an ultra-rare disorder caused by mutations in TYMP, leading to a deficiency in thymidine phosphorylase and a subsequent systemic accumulation of thymidine and 2'-deoxyuridine. Erythrocyte-encapsulated thymidine phosphorylase (EE-TP) is under clinical development as an enzyme replacement therapy for MNGIE. Bioanalytical methods were developed according to regulatory guidelines for the quantification of thymidine and 2'-deoxyuridine in plasma and urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for supporting the pharmacodynamic evaluation of EE-TP. Samples were deproteinized with 5% perchloric acid (v/v) and the supernatants analyzed using a Hypercarb column (30 × 2.1 mm, 3 µm), with mobile phases of 0.1% formic acid in methanol and 0.1% formic acid in deionized water. Detection was conducted using an ion-spray interface running in positive mode. Isotopically labelled thymidine and 2'-deoxyuridine were used as internal standards. Calibration curves for both metabolites showed linearity (r > 0.99) in the concentration ranges of 10-10,000 ng/mL for plasma, and 1-50 µg/mL for urine, with method analytical performances within the acceptable criteria for quality control samples. The plasma method was successfully applied to the diagnosis of two patients with MNGIE and the quantification of plasma metabolites in three patients treated with EE-TP

Anomalous resistance overshoot in the integer quantum Hall effect

In this work we report experiments on defined by shallow etching narrow Hall bars. The magneto-transport properties of intermediate mobility two-dimensional electron systems are investigated and analyzed within the screening theory of the integer quantized Hall effect. We observe a non-monotonic increase of Hall resistance at the low magnetic field ends of the quantized plateaus, known as the overshoot effect. Unexpectedly, for Hall bars that are defined by shallow chemical etching the overshoot effect becomes more pronounced at elevated temperatures. We observe the overshoot effect at odd and even integer plateaus, which favor a spin independent explanation, in contrast to discussion in the literature. In a second set of the experiments, we investigate the overshoot effect in gate defined Hall bar and explicitly show that the amplitude of the overshoot effect can be directly controlled by gate voltages. We offer a comprehensive explanation based on scattering between evanescent incompressible channels.Comment: 7 pages and 5 figure

Application of the bentix index in assessing ecological quality of hard substrata: a case study from the Bosphorus Strait, Turkey

In this paper, a biotic index (Bentix) has been used for the assessment of ecological quality status of shallow water hard substrate benthic ecosystems affected by coastal sewage discharges in the Bosphorus Strait. A significant difference was observed between the control and the discharge stations with regard to Bentix values (Mann-Whitney U Test, p=0.002) and ecological quality status of the discharge stations was worse than that of controls. The index values revealed that sewage discharges caused serious disturbance in macrozoobenthic communities in the area investigated. Although so far it has been used for soft bottom communities, Bentix (with some species scoring modifications) also appeared to work successfully in hard substrates, at least for the present study

On the Occurrence and Established Populations of the Alien Polychaete Polydora cornuta Bosc, 1802 (Polychaeta: Spionidae) in the Sea of Marmara and the Bosphorus Strait (Turkey)

The present paper reports the first occurrence of Polydora cornuta in the Bosphorus Strait and its finding in a new locality in the Sea of Marmara, providing a link with its Aegean and Black Sea populations. The probable vector for the introduction of P. cornuta into the Sea of Marmara is shipping through the Dardanelles Strait. Both soft and hard-bottom populations were examined and the importance and prevalence of this species within the native macrozoobenthic communities were elucidated. Its abundance ranged between 40 and 3390 ind.m-2 (mean:1320 ±1199.45 SD) and its percent contribution to the total faunal populations ranged between 3.31 and 75.56 (mean:27.79 ±25.00 SD) in the Sea of Marmara softbottom community. During the sampling period, P. cornuta contributed little to the total faunal abundance of the hard-bottom communities in the Bosphorus Strait. Its mean abundance in the hard substrate ranged between 8.33 and 1000 ind.m-2 (mean:117.36 ±279.73 SD) and its percent contribution to the total faunal populations ranged between 0.02 and 21.86 (mean:2.07 ±6.25 SD). The role of this invasive species in the soft-bottom macrobenthic community at an organically enriched site examined in the Sea of Marmara is highlighted, and a comparison with Aegean Sea populations of the species is also included

Management of spontaneous pneumothorax in patients with COVID-19.

ObjectivesThe coronavirus disease 2019 (COVID-19) pneumonia may cause cystic features of lung parenchyma which can resolve or progress to larger blebs. Pneumothorax was more likely in patients with neutrophilia, severe lung injury and a prolonged clinical course. The timely diagnosis and management will reduce COVID-19-associated morbidity and mortality.MethodsWe present 11 cases of spontaneous pneumothorax managed with chest tube thoracostomy or high-dose oxygen therapy. Isolated spontaneous pneumothorax was detected in all cases.ResultsEight cases were male and 3 cases were female. There were bilateral ground-glass opacities or pulmonary infiltrates in the parenchyma of the 10 cases. We detected neutrophilia, lymphopaenia and increased C-reactive protein, Ferritin, lactate dehydrogenase, D-Dimer, interleukin-6 levels in almost all cases. Chest tube thoracostomy was sufficient to treat pneumothorax in our 9 of case. In 2 cases, pneumothorax healed with high-dose oxygen therapy. Favipiravir and antibiotic treatment were given to different 10 patients. In our institution, all patients with COVID-19 infection were placed on prophylactic or therapeutic anticoagulation, unless contraindicated. The treatments of patients diagnosed with secondary spontaneous pneumothorax during the pandemic period and those diagnosed with secondary spontaneous pneumothorax in the previous 3 years were compared with the durations of tube thoracostomy performed in both groups.ConclusionsThe increased number of cases of pneumothorax suggests that pneumothorax may be a complication of COVID-19 infection. During medical treatment of COVID-19, pneumothorax may be the only reason for hospitalization. Although tube thoracostomy is a sufficient treatment option in most cases, clinicians should be aware of the difficulties that may arise in diagnosis and treatment