Thermochemical investigations of hydrolysis of p-nitrophenyl acetate in water-acetontrile mixtures

The α-chymotrypsin-catalyzed hydrolysis of the p-nitrophenyl acetate in the solvent mixtures containing from 1.6 up to 10% (v/v) acetonitrile in the presence of aqueous Tris buffer at pH 8.0 was investigated at 298 K by use of an isoperibolic batch calorimeter. A special experimental arrangement of the reaction components for the investigation of the hydrolytically instable substrate was used. Furthermore, the release of p-nitrophenol was recorded with an UV-vis-spectrophotometer under comparable conditions. The calorimetric curves consist of two parts. The first part is strongly rising and finished by a break point in the ΔT (time) curve. This first step is dominated by the enzyme-catalyzed reaction. After the break point a slow non-enzymatic process determines the course of the calorimetric curve. The molar enthalpy changes of overall reaction (ester hydrolysis and buffer protonation) of -100 ± 8, -106 ± 5 and -102 ± 5 kJ/mol were evaluated by a combination of the results from the spectrophotometric and calorimetric data for 1.6, 4.0 and 10.0% acetonitrile mixtures, respectively. The obtained results indicate that the enzyme-catalyzed hydrolysis is suitable for quantitative determination of the hydrophobic ester p-nitrophenyl acetate in water-acetonitrile mixtures using calorimetric detection. © 2004 Elsevier B.V. All rights reserved

Effect of sleeve gastrectomy on postprandial lipoprotein metabolism in morbidly obese patients

Background: Obesity is associated with abnormal fasting and postprandial lipids, which may link obesity with atherosclerosis. We explored fasting and postprandial lipids in morbidly obese patients treated with sleeve gastrectomy and in control subjects. Methods: After fasting for 12 h 15 morbidly obese patients (BMI 51.4 +/- 6.5 kg/m(2), 43.7 +/- 12.6 years) received a standardized oral fat load before and 3 months after bariatric surgery (sleeve gastrectomy). Controls (n=9, BMI 23.1 +/- 1.4 kg/m(2)) were studied once. Plasma was obtained fasting and then postprandially every 2 h for 8 h. Triglycerides (TG), chylomicron-TG (CM-TG), VLDL/chylomicron-remnant (VLDL/CR)-TG, cholesterol, LDL-cholesterol, VLDL/CR-cholesterol and HDL-cholesterol were isolated by ultracentrifugation at each time point. Postprandial values were expressed as area under the curve (AUC) and incremental area under the curve (iAUC). In addition, fasting glucose and insulin values and HOMA-IR-Index was measured (n=14). Results: Compared to controls morbidly obese patients had elevated TG and slightly altered postprandial lipids. Following surgery (weight loss 23.4 kg +/- 6.2 kg; 150 mg/dl) a similar pattern was observed. Fasting insulin and HOMA were reduced significantly (-51.9%; p=0.004 and -47.9%; p=0.011). Conclusions: Three months after sleeve gastrectomy fasting and postprandial lipoprotein metabolism and glucose metabolism is improved in morbidly obese patients. The potential mechanisms may relate to decreased caloric intake but also to hormonal changes

RNA Sequencing of Human Peripheral Nerve in Response to Injury: Distinctive Analysis of the Nerve Repair Pathways

The development of regenerative therapies for central nervous system diseases can likely benefit from an understanding of the peripheral nervous system repair process, particularly in identifying potential gene pathways involved in human nerve repair. This study employed RNA sequencing (RNA-seq) technology to analyze the whole transcriptome profile of the human peripheral nerve in response to an injury. The distal sural nerve was exposed, completely transected, and a 1 to 2 cm section of nerve fascicles was collected for RNA-seq from six participants with Parkinson\u27s disease, ranging in age between 53 and 70 yr. Two weeks after the initial injury, another section of the nerve fascicles of the distal and pre-degenerated stump of the nerve was dissected and processed for RNA-seq studies. An initial analysis between the pre-lesion status and the postinjury gene expression revealed 3,641 genes that were significantly differentially expressed. In addition, the results support a clear transdifferentiation process that occurred by the end of the 2-wk postinjury. Gene ontology (GO) and hierarchical clustering were used to identify the major signaling pathways affected by the injury. In contrast to previous nonclinical studies, important changes were observed in molecular pathways related to antiapoptotic signaling, neurotrophic factor processes, cell motility, and immune cell chemotactic signaling. The results of our current study provide new insights regarding the essential interactions of different molecular pathways that drive neuronal repair and axonal regeneration in humans

Thymic Hyperplasia with Lymphoepithelial Sialadenitis (LESA)-Like Features: Strong Association with Lymphomas and Non-Myasthenic Autoimmune Diseases.

Thymic hyperplasia (TH) with lymphoepithelial sialadenitis (LESA)-like features (LESA-like TH) has been described as a tumor-like, benign proliferation of thymic epithelial cells and lymphoid follicles. We aimed to determine the frequency of lymphoma and autoimmunity in LESA-like TH and performed retrospective analysis of cases with LESA-like TH and/or thymic MALT-lymphoma. Among 36 patients (21 males) with LESA-like TH (age 52 years, 32-80; lesion diameter 7.0 cm, 1-14.5; median, range), five (14%) showed associated lymphomas, including four (11%) thymic MALT lymphomas and one (3%) diffuse large B-cell lymphoma. One additional case showed a clonal B-cell-receptor rearrangement without evidence of lymphoma. Twelve (33%) patients (7 women) suffered from partially overlapping autoimmune diseases: systemic lupus erythematosus (n = 4, 11%), rheumatoid arthritis (n = 3, 8%), myasthenia gravis (n = 2, 6%), asthma (n = 2, 6%), scleroderma, Sjögren syndrome, pure red cell aplasia, Grave's disease and anti-IgLON5 syndrome (each n = 1, 3%). Among 11 primary thymic MALT lymphomas, remnants of LESA-like TH were found in two cases (18%). In summary, LESA-like TH shows a striking association with autoimmunity and predisposes to lymphomas. Thus, a hematologic and rheumatologic workup should become standard in patients diagnosed with LESA-like TH. Radiologists and clinicians should be aware of LESA-like TH as a differential diagnosis for mediastinal mass lesions in patients with autoimmune diseases

Npn-1 Contributes to Axon-Axon Interactions That Differentially Control Sensory and Motor Innervation of the Limb

The initiation, execution, and completion of complex locomotor behaviors are depending on precisely integrated neural circuitries consisting of motor pathways that activate muscles in the extremities and sensory afferents that deliver feedback to motoneurons. These projections form in tight temporal and spatial vicinities during development, yet the molecular mechanisms and cues coordinating these processes are not well understood. Using cell-type specific ablation of the axon guidance receptor Neuropilin-1 (Npn-1) in spinal motoneurons or in sensory neurons in the dorsal root ganglia (DRG), we have explored the contribution of this signaling pathway to correct innervation of the limb. We show that Npn-1 controls the fasciculation of both projections and mediates inter-axonal communication. Removal of Npn-1 from sensory neurons results in defasciculation of sensory axons and, surprisingly, also of motor axons. In addition, the tight coupling between these two heterotypic axonal populations is lifted with sensory fibers now leading the spinal nerve projection. These findings are corroborated by partial genetic elimination of sensory neurons, which causes defasciculation of motor projections to the limb. Deletion of Npn-1 from motoneurons leads to severe defasciculation of motor axons in the distal limb and dorsal-ventral pathfinding errors, while outgrowth and fasciculation of sensory trajectories into the limb remain unaffected. Genetic elimination of motoneurons, however, revealed that sensory axons need only minimal scaffolding by motor axons to establish their projections in the distal limb. Thus, motor and sensory axons are mutually dependent on each other for the generation of their trajectories and interact in part through Npn-1-mediated fasciculation before and within the plexus region of the limbs

Egr3 Dependent Sympathetic Target Tissue Innervation in the Absence of Neuron Death

Nerve Growth Factor (NGF) is a target tissue derived neurotrophin required for normal sympathetic neuron survival and target tissue innervation. NGF signaling regulates gene expression in sympathetic neurons, which in turn mediates critical aspects of neuron survival, axon extension and terminal axon branching during sympathetic nervous system (SNS) development. Egr3 is a transcription factor regulated by NGF signaling in sympathetic neurons that is essential for normal SNS development. Germline Egr3-deficient mice have physiologic dysautonomia characterized by apoptotic sympathetic neuron death and abnormal innervation to many target tissues. The extent to which sympathetic innervation abnormalities in the absence of Egr3 is caused by altered innervation or by neuron death during development is unknown. Using Bax-deficient mice to abrogate apoptotic sympathetic neuron death in vivo, we show that Egr3 has an essential role in target tissue innervation in the absence of neuron death. Sympathetic target tissue innervation is abnormal in many target tissues in the absence of neuron death, and like NGF, Egr3 also appears to effect target tissue innervation heterogeneously. In some tissues, such as heart, spleen, bowel, kidney, pineal gland and the eye, Egr3 is essential for normal innervation, whereas in other tissues such as lung, stomach, pancreas and liver, Egr3 appears to have little role in innervation. Moreover, in salivary glands and heart, two tissues where Egr3 has an essential role in sympathetic innervation, NGF and NT-3 are expressed normally in the absence of Egr3 indicating that abnormal target tissue innervation is not due to deregulation of these neurotrophins in target tissues. Taken together, these results clearly demonstrate a role for Egr3 in mediating sympathetic target tissue innervation that is independent of neuron survival or neurotrophin deregulation

Molecular characterization of the enhancing immunoglobulin of mice. Abstr.

The α-chymotrypsin-catalyzed hydrolysis of the p-nitrophenyl acetate in the solvent mixtures containing from 1.6 up to 10% (v/v) acetonitrile in the presence of aqueous Tris buffer at pH 8.0 was investigated at 298 K by use of an isoperibolic batch calorimeter. A special experimental arrangement of the reaction components for the investigation of the hydrolytically instable substrate was used. Furthermore, the release of p-nitrophenol was recorded with an UV-vis-spectrophotometer under comparable conditions. The calorimetric curves consist of two parts. The first part is strongly rising and finished by a break point in the ΔT (time) curve. This first step is dominated by the enzyme-catalyzed reaction. After the break point a slow non-enzymatic process determines the course of the calorimetric curve. The molar enthalpy changes of overall reaction (ester hydrolysis and buffer protonation) of -100 ± 8, -106 ± 5 and -102 ± 5 kJ/mol were evaluated by a combination of the results from the spectrophotometric and calorimetric data for 1.6, 4.0 and 10.0% acetonitrile mixtures, respectively. The obtained results indicate that the enzyme-catalyzed hydrolysis is suitable for quantitative determination of the hydrophobic ester p-nitrophenyl acetate in water-acetonitrile mixtures using calorimetric detection. © 2004 Elsevier B.V. All rights reserved

Thermochemical investigations of hydrolysis of p-nitrophenyl acetate in water-acetontrile mixtures

The α-chymotrypsin-catalyzed hydrolysis of the p-nitrophenyl acetate in the solvent mixtures containing from 1.6 up to 10% (v/v) acetonitrile in the presence of aqueous Tris buffer at pH 8.0 was investigated at 298 K by use of an isoperibolic batch calorimeter. A special experimental arrangement of the reaction components for the investigation of the hydrolytically instable substrate was used. Furthermore, the release of p-nitrophenol was recorded with an UV-vis-spectrophotometer under comparable conditions. The calorimetric curves consist of two parts. The first part is strongly rising and finished by a break point in the ΔT (time) curve. This first step is dominated by the enzyme-catalyzed reaction. After the break point a slow non-enzymatic process determines the course of the calorimetric curve. The molar enthalpy changes of overall reaction (ester hydrolysis and buffer protonation) of -100 ± 8, -106 ± 5 and -102 ± 5 kJ/mol were evaluated by a combination of the results from the spectrophotometric and calorimetric data for 1.6, 4.0 and 10.0% acetonitrile mixtures, respectively. The obtained results indicate that the enzyme-catalyzed hydrolysis is suitable for quantitative determination of the hydrophobic ester p-nitrophenyl acetate in water-acetonitrile mixtures using calorimetric detection. © 2004 Elsevier B.V. All rights reserved