Publications by authors named "Knop R"

Nutritional cues during embryonic development can alter developmental trajectories and affect postnatal growth. However, the specific mechanisms by which nutrients influence avian growth remain largely unknown. Amino acids can directly interact with the nutrient-sensing pathways, such as the insulin-like growth factor 1 (IGF-1)/mechanistic target of rapamycin (mTOR) pathways, which are known to regulate growth.

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Nutritional limitation is a common phenomenon in nature that leads to trade-offs among processes competing for limited resources. These trade-offs are mediated by changes in physiological traits such as growth factors and circulating lipids. However, studies addressing the sex-specific effect of nutritional deficiency on these physiological variables are limited in birds.

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Limited resources affect an organism's physiology through the conserved metabolic pathway, the mechanistic target of rapamycin (mTOR). Males and females often react differently to nutritional limitation, but whether it leads to differential mTOR pathway expression remains unknown. Recently, we found that dietary restriction (DR) induced significant changes in the expression of mTOR pathway genes in female Japanese quails (Coturnix japonica).

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Resources are needed for growth, reproduction and survival, and organisms must trade off limited resources among competing processes. Nutritional availability in organisms is sensed and monitored by nutrient-sensing pathways that can trigger physiological changes or alter gene expression. Previous studies have proposed that one such signalling pathway, the mechanistic target of rapamycin (mTOR), underpins a form of adaptive plasticity when individuals encounter constraints in their energy budget.

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Embryonic development is one of the most sensitive and critical stages when maternal effects may influence the offspring's phenotype. In birds and other oviparous species, embryonic development is confined to the eggs, therefore females must deposit resources into the eggs to prepare the offspring for the prevailing post-natal conditions. However, the mechanisms of such phenotypic adjustments remain poorly understood.

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Methionine (Met) plays a substantial role in poultry due to its involvement in several pathways, including enhancing antioxidant status and improving growth performance and health status. This study examined how in ovo feeding of Met affects hatching performance, antioxidant status, and hepatic gene expression related to growth and immunity in the TETRA-SL LL hybrid (TSL) commercial layer and Hungarian partridge colored hen (HPC) indigenous genotypes. The eggs were injected with saline, DL-Met, and L-Met on 17.

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Methionine (Met) is an essential and first limiting amino acid in the poultry diet that plays a significant role in chicken embryonic development and growth. The present study examined the effect of in ovo injection of DL-Met and L-Met sources and genotypes on chicken embryonic-intestinal development and health. Fertilized eggs of the two genotypes, TETRA-SL layer hybrid (TSL) - commercial layer hybrid and Hungarian Partridge colored hen breed (HPC) - a native genotype, were randomly distributed into four treatments for each genotype.

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Unlabelled: infections have become a major challenge in medical facilities. The bacterium is capable of spore formation allowing the survival of antibiotic treatment. Therefore, research on the physiology of is important for the development of alternative treatment strategies.

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Due to the legislation of antibiotic usage, natural substances are required for application in the poultry industry. Because of their potential anti-inflammatory and immunomodulatory effects, carotenoids are great sources. Capsanthin, a major carotenoid giving the red color of pepper, is a promising feed additive, as it can reduce chronic inflammation.

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The aim of this study was to estimate the occurrence of bacterial infection and contamination in two ostrich-producing farms. Compared to other poultry species, the hatchability of ostrich eggs is especially low. In a quest to identify factors that may affect hatchability, we collected faecal samples from adult birds, as well as eggs with dead-in-shell embryos, dead chicks and swab samples from the surface of the eggs and from the environment.

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The study was carried out to determine whether sources or levels of methionine (Met) affect the health status of Tetra-SL (TSL) chicks by examining growth performance, feather growth, and hematological parameters. A total of ninety-six (96) day-old (44.2 ± 0.

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Pancreatic diseases, which include diabetes, pancreatitis, and pancreatic cancer, are often difficult to detect and/or stage, contributing to a reduced quality of life and lifespan for patients. Thus, there is need for a technology that can visualize tissue changes in the pancreas, improve understanding of disease progression, and facilitate earlier detection in the human population. Because of low spatial resolution, current clinical magnetic resonance imaging (MRI) at low field strength has yet to fully visualize the exocrine, endocrine, vascular, and stromal components of the pancreas.

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Purpose: To determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of gemcitabine using a fixed dose rate infusion (FDRI) in combination with gefitinib in patients (pts) with pancreatic adenocarcinoma (PCa).

Patients And Methods: Patients with advanced PCa were given gemcitabine at the FDRI of 10 mg/m(2)/min IV on Days 1, 8, and 15 of a 28-day cycle. Dose levels of 1000, 1200, and 1500 mg/m(2) were evaluated.

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The phylogenetic relationships of calcareous dinoflagellates (i.e., Calciodinellaceae and Thoracosphaera) are investigated.

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Metabolism of trifluorothymidine (TFT) and its transport across the blood-brain barrier (BBB) has been measured quantitatively in rats by fluorine-19 nuclear magnetic resonance spectroscopy ((19)F NMR). It is demonstrated that TFT crosses the BBB in micromolar quantities and is metabolized in brain tissue primarily to its free base trifluoromethyluracil (TFMU) by the enzyme thymidine phosphorylase (TP). It is further proposed that the rate of TFMU production can be used as a measure of cerebral TP.

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Accumulation of CO(2) in animal cell cultures can be a significant problem during scale-up and production of recombinant glycoprotein biopharmaceuticals. By examining the cell-surface polysialic acid (PSA) content, we show that elevated CO(2) partial pressure (pCO(2)) can alter protein glycosylation. PSA is a high-molecular-weight polymer attached to several complex N-linked oligosaccharides on the neural cell adhesion molecule (NCAM), so that small changes in either core glycosylation or in polysialylation are amplified and easily measured.

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Ammonia in animal cell cultures has been shown to specifically inhibit terminal sialylation of N- and O-linked oligosaccharides of glycoproteins. For example, we have previously shown that as little as 2.5 mM NH4Cl can decrease neural cell adhesion molecule (NCAM) polysialylation in both small cell lung cancer (SCLC) and Chinese hamster ovary (CHO) cells.

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Ammonia is a major concern in biotechnology because it often limits recombinant protein production by animal cells. Conditions, such as ammonia accumulation, in large-scale production systems can parallel those that develop within fast-growing solid tumors such as small cell lung cancer (SCLC). Ammonia's specific inhibition of the sialylation of secreted glycoproteins is well documented, but it is not known how ammonia affects membrane-bound proteins, nor what role it may have on important glycosylation determinants in cancer.

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Purpose: Alkylating agents have modest activity in advanced urothelial carcinoma. Ifosfamide (IFX) is an agent as yet unstudied in advanced urothelial carcinoma. Despite recent advances in the treatment of this disease, there continues to be a need to identify new active agents and their toxicity spectra.

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31P-NMR extract spectra of N-417 Small Cell Lung Cancer (SCLC) cells cultured with fluorouridine (FUrd) reveal new peaks with chemical shifts in the diphosphodiester and nucleoside triphosphate regions. These peaks were identified as FUTP, FUDP, FUDP-glucose, FUDP-glucuronate, FUDP-GlcNAc, and FUDP-GalNAc via enzymatic conversion and 19F- and 31P-NMR analysis. Distinct 19F chemical shifts were assigned for FUTP, FUDP, and the FUDP-sugars.

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Thirty-three patients with advanced colorectal carcinoma were entered on a phase II trial of weekly IV aminothiadiazole (175 mg/m2 escalated to 200 mg/m2) with concomitant allopurinol and non-steroidal anti-inflammatory agents (NSAID's). Toxicity was predominantly GI, cutaneous, and chest pain/dyspnea. Twenty-five percent of patients had grade 3 or 4 toxicity.

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Natural abundance 13C NMR was used to determine relative amounts of fatty acid subclasses present in fibroadipose tissue from the human breast in healthy and cancer patients and in breast carcinoma tissue. Resonances corresponding to the carbon atoms of triacylglycerides were obtained when adipose tissue constituted more than 10% of the carcinoma. Resonances corresponding to phospholipids and proteins were also observed when the percentage of adipose tissue was lower.

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Small cell lung cancer (SCLC) occurs as two neuroendocrine subtypes, SCLC-C (classic) and SCLC-V (variant). One reported difference is elevated levels of diphosphodiesters (DPDE) in the more differentiated SCLC-C subtype. DPDE have been identified as primarily UDP-N-acetylhexosamines (UDP-NAH) in a variety of tumors, and changes in DPDE levels have been observed during experiments designed to induce cell differentiation.

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