Symmetry Properties on Magnetization in the Hubbard Model at Finite Temperatures

By making use of some symmetry properties of the relevant Hamiltonian, two fundamental relations between the ferromagnetic magnetization and a spin correlation function are derived for the $d (=1,2,3)$-dimensional Hubbard model at finite temperatures. These can be viewed as a kind of Ward-Takahashi identities. The properties of the magnetization as a function of the applied field are discussed. The results thus obtained hold true for both repulsive and attractive on-site Coulomb interactions, and for arbitrary electron fillings.Comment: Latex file, no figur

International Veterinary Epilepsy Task Force recommendations for systematic sampling and processing of brains from epileptic dogs and cats

Traditionally, histological investigations of the epileptic brain are required to identify epileptogenic brain lesions, to evaluate the impact of seizure activity, to search for mechanisms of drug-resistance and to look for comorbidities. For many instances, however, neuropathological studies fail to add substantial data on patients with complete clinical work-up. This may be due to sparse training in epilepsy pathology and or due to lack of neuropathological guidelines for companion animals. The protocols introduced herein shall facilitate systematic sampling and processing of epileptic brains and therefore increase the efficacy, reliability and reproducibility of morphological studies in animals suffering from seizures. Brain dissection protocols of two neuropathological centres with research focus in epilepsy have been optimised with regards to their diagnostic yield and accuracy, their practicability and their feasibility concerning clinical research requirements. The recommended guidelines allow for easy, standardised and ubiquitous collection of brain regions, relevant for seizure generation. Tissues harvested the prescribed way will increase the diagnostic efficacy and provide reliable material for scientific investigations

A Novel Screening System for Claudin Binder Using Baculoviral Display

Recent progress in cell biology has provided new insight into the claudin (CL) family of integral membrane proteins, which contains more than 20 members, as a target for pharmaceutical therapy. Few ligands for CL have been identified because it is difficult to prepare CL in an intact form. In the present study, we developed a method to screen for CL binders by using the budded baculovirus (BV) display system. CL4-displaying BV interacted with a CL4 binder, the C-terminal fragment of Clostridium perfringens enterotoxin (C-CPE), but it did not interact with C-CPE that was mutated in its CL4-binding region. C-CPE did not interact with BV and CL1-displaying BV. We used CL4-displaying BV to select CL4-binding phage in a mixture of a scFv-phage and C-CPE-phage. The percentage of C-CPE-phage in the phage mixture increased from 16.7% before selection to 92% after selection, indicating that CL-displaying BV may be useful for the selection of CL binders. We prepared a C-CPE phage library by mutating the functional amino acids. We screened the library for CL4 binders by affinity to CL4-displaying BV, and we found that the novel CL4 binders modulated the tight-junction barrier. These findings indicate that the CL-displaying BV system may be a promising method to produce a novel CL binder and modulator

Pituitary Adenylate Cyclase-Activating Polypeptide Stimulates Glucose Production via the Hepatic Sympathetic Innervation in Rats

OBJECTIVE-The unraveling of the elaborate brain networks that control glucose metabolism presents one of the current challenges in diabetes research. Within the central nervous system, the hypothalamus is regarded as the key brain area to regulate energy homeostasis. The aim of the present study was to investigate the hypothalamic mechanism involved in the hyperglycemic effects of the neuropeptide pituitary adenylyl cyclase-activating polypeptide (PACAP). RESEARCH DESIGN AND METHODS-Endogenous glucose production (EGP) was determined during intracerebroventricular infusions of PACAP-38, vasoactive intestinal peptide (VIP), or their receptor agonists. The specificity of their receptors was examined by coinfusions of receptor antagonists. The possible neuronal pathway involved was investigated by 1) local injections in hypothalamic nuclei, 2) retrograde neuronal tracing from the thoracic spinal cord to hypothalamic preautonomic neurons together with Fos immunoreactivity, and 3) specific hepatic sympathetic or parasympathetic denervation to block the autonomic neuronal input to liver. LTS-Intracerebroventiicular infusion of PACAP-38 increased EGP to a similar extent as a VIP/PACAP-2 (VPAC2) receptor agonist, and intracerebroventricular administration of VIP had significantly less influence on EGP. The PACAP-38 induced increase of EGP was significantly suppressed by preinfusion of a VPAC2 but not a PAC1 receptor antagonist, as well as by hepatic sympathetic but not parasympathetic denervation. In the hypothalamus, Fos immunoreactivity induced by PACAP-38 was colocalized within autonomic neurons in paraventricular nuclei projecting to preganglionic sympathetic neurons in the spinal cord. Local infusion of PACAP-38 directly into the PVN induced a significant increase of EGP. CONCLUSIONS-This study demonstrates that PACAP-38 signaling via sympathetic preautonomic neurons located in the paraventricular nucleus is an important component in the hypothalamic control of hepatic glucose production. Diabetes 59: 1591-1600, 201

Physiogenomic analysis of weight loss induced by dietary carbohydrate restriction

BACKGROUND: Diets that restrict carbohydrate (CHO) have proven to be a successful dietary treatment of obesity for many people, but the degree of weight loss varies across individuals. The extent to which genetic factors associate with the magnitude of weight loss induced by CHO restriction is unknown. We examined associations among polymorphisms in candidate genes and weight loss in order to understand the physiological factors influencing body weight responses to CHO restriction. METHODS: We screened for genetic associations with weight loss in 86 healthy adults who were instructed to restrict CHO to a level that induced a small level of ketosis (CHO ~10% of total energy). A total of 27 single nucleotide polymorphisms (SNPs) were selected from 15 candidate genes involved in fat digestion/metabolism, intracellular glucose metabolism, lipoprotein remodeling, and appetite regulation. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. RESULTS: Mean weight loss was 6.4 kg. SNPs in the gastric lipase (LIPF), hepatic glycogen synthase (GYS2), cholesteryl ester transfer protein (CETP) and galanin (GAL) genes were significantly associated with weight loss. CONCLUSION: A strong association between weight loss induced by dietary CHO restriction and variability in genes regulating fat digestion, hepatic glucose metabolism, intravascular lipoprotein remodeling, and appetite were detected. These discoveries could provide clues to important physiologic adaptations underlying the body mass response to CHO restriction