Distribution of Fos-immunoreactive cells in rat forebrain and midbrain following social defeat stress and diazepam treatment

The anxiolytic diazepam selectively inhibits psychological stress-induced autonomic and behavioral responses without causing noticeable suppression of other central performances. This pharmacological property of diazepam led us to the idea that neurons that exhibit diazepam-sensitive, psychological stress-induced activation are potentially those recruited for stress responses. To obtain neuroanatomical clues for the central stress circuitries, we examined the effects of diazepam on psychological stress-induced neuronal activation in broad brain regions. Rats were exposed to a social defeat stress, which caused an abrupt increase in body temperature by up to 2°C. Pretreatment with diazepam (4mg/kg, i.p.) attenuated the stress-induced hyperthermia, confirming an inhibitory physiological effect of diazepam on the autonomic stress response. Subsequently, the distribution of cells expressing Fos, a marker of neuronal activation, was examined in 113 forebrain and midbrain regions of these rats after the stress exposure and diazepam treatment. The stress following vehicle treatment markedly increased Fos-immunoreactive (IR) cells in most regions of the cerebral cortex, limbic system, thalamus, hypothalamus and midbrain, which included parts of the autonomic, neuroendocrine, emotional and arousal systems. The diazepam treatment significantly reduced the stress-induced Fos expression in many brain regions including the prefrontal, sensory and motor cortices, septum, medial amygdaloid nucleus, medial and lateral preoptic areas, parvicellular paraventricular hypothalamic nucleus, dorsomedial hypothalamus, perifornical nucleus, tuberomammillary nucleus, association, midline and intralaminar thalami, and median and dorsal raphe nuclei. In contrast, diazepam increased Fos-IR cells in the central amygdaloid nucleus, medial habenular nucleus, ventromedial hypothalamic nucleus and magnocellular lateral hypothalamus. These results provide important information for elucidating the neural circuitries that mediate the autonomic and behavioral responses to psychosocial stressors.

Enhanced selective lymphatic delivery of cyclosporin a by solubilizers and intensified immunosuppressive activity against mice skin allograft

The absorption and lymphatic delivery of a new immunosuppressive drug, cyclosporin A (CsA), were studied in rats by administering CsA orally after solubilization with HCO-60 (polyoxyethylated hydrogenated castor oil), sugar ester, and oils. After the administration of solubilized CsA (7 mg/kg) to rats with thoracic lymph duct cannulas, both plasma and lymph CsA levels were measured over 6 hr. The lymph CsA levels were strongly affected by the solubilizers. The rank order of the solubilizers in enhancing lymph absorption was HCO-60 (57 µg/ml) > sugar ester (46 µg/ml) > sesame oil (3.5 µg/ml) > linoleic acid (0.4 µg/ml), where the parentheses show the maximum lymph CsA levels. Plasma CsA levels were below 2 µg/ml in each group of animals and were barely altered by the solubilizers. These results support the selective lymphatic delivery of CsA with solubilizers such as HCO-60 and sugar ester. The immunosuppressive activity of CsA (1 mg/kg) solubilized with HCO-60 was nearly equivalent to the sesame oil solution with 7 to 15 mg/kg CsA in the skin-allograft mice model.

Possible involvement of A₂A and A₃ receptors in modulation of insulin secretion and β-cell survival in mouse pancreatic islets

Adenosine A1, A₂A, A₂B and A₃ receptor mRNAs were found to be expressed in mouse pancreatic islets and Beta-TC6 cells but their physiological or pharmacological actions are not fully clarified. We showed that adenosine (100 μM) augmented insulin secretion by islets in the presence of either normal (5.5 mM) or a high concentration of glucose (20 mM). The augmentation of insulin secretion in the presence of high glucose was blocked by an A₂A antagonist, but not by A₂B and A₃ antagonists, while an A₁ antagonist potentiated the adenosine effect. An adenosine analogue 5'-N-ethylcarboxamidoadenosine (NECA) as well as A₁, A₂A and A₃ receptor agonists also produced stimulation. On the other hand, an A₃ agonist markedly reduced Beta-TC6 cell proliferation and the islet cell viability, while adenosine and NECA did not. The effect of A₃ agonist was partially blocked by the A₃ antagonist. In addition, treatment with the A₃ agonist produced a small but significant extent of apoptosis in Beta-TC6 cells as judged by terminal transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) assay. These results combined together suggested that like the A₁ receptor, activation of A₂A receptors by adenosine results in augmented insulin secretion, while the A₃ receptor is involved in modulation of the survival of pancreatic β-cells.

Distribution of pituitary adenylate cyclase-activating polypeptide (PACAP) in the human testis and in testicular germ cell tumors

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide expressed in the central nervous system and peripheral organs. Previous studies revealed the role and distribution of PACAP in the rodent testis, however, its presence in the human testis and in testicular germ cell tumors is not known. We used RT-PCR and immunohistological observations to investigate whether human testicular tissue and testicular germ cell tumors contain PACAP. The mRNAs for PACAP and its receptors were detected in total RNA extracted from human testes. PACAP immunoreactivity was observed in spermatogonia and spermatids from normal testes. In contrast, diffuse PACAP immunopositivity was observed in seminoma tumor cells, while only faint immunoreactivity was observed in embryonal carcinoma cells. Our data suggest that PACAP may play a role in human spermatogenesis and in testicular germ cell tumor development.

Radiolabeled RGD peptides as integrin alpha(v)beta3-targeted PET tracers

Imaging techniques targeting tumor angiogenesis have been investigated for past decade. Of these, the radiolabeled Arg-Gly- Asp (RGD) peptide has been focused because it has high affinity and selectivity for integrin alpha(v)beta3. Integrin alpha(v)beta3 is expressed on the plasma membrane in an active status in which it binds its ligands and transduce signals when exposed activating external stimuli of tumor angiogenesis such as vascular endothelial growth factor (VEGF). Many linear or cyclic RGD peptides were developed for positron emission tomography (PET). In this review, we focused on currently developed RGD peptides as PET probes for non-invasive detection of integrin alpha(v)beta3 expression.

Unpaired electron species in thin films of calf-thymus DNA molecules induced by nitrogen and oxygen K-shell photoabsorption

The mechanism of DNA modification induced by K-shell photoabsorption of nitrogen and oxygen atoms was investigated by electron paramagnetic resonance and x-ray absorption near edge structure measurements of calf thymus DNA. A g factor of 2.000 for the unpaired electron species, which only arises during irradiation, was measured. The EPR intensities for DNA zwere twofold times larger than those estimated based on the photoabsorption cross section. This suggests that the DNA film itself forms unpaired electron species through the excitation of enhanced electron recapturing, known as the postcollision interaction process.

Modulation of gene expression by vitamin B6

The physiologically active form of vitamin B6, pyridoxal 5'-phosphate (PLP), is known to function as a cofactor in many enzymic reactions in amino acid metabolism. Recent studies have shown that, apart from its role as a coenzyme, PLP acts as a modulator of steroid hormone receptor-mediated gene expression. Specifically, elevation of intracellular PLP leads to a decreased transcriptional response to glucocorticoid hormones, progesterone, androgens, and oestrogens. For example, the induction of cytosolic aspartate aminotransferase (cAspAT) in rat liver by hydrocortisone is suppressed by the administration of pyridoxine. The suppression of the cAspAT induction by pyridoxine is caused by a decrease in the expression of the cAspAT gene, which is brought about by inactivation of the binding activity of the glucocorticoid receptor to the glucocorticoid-responsive element in the regulatory region of the cAspAT gene. Vitamin B6 has recently been found to modulate gene expression not only for steroid hormone-responsive or PLP-dependent enzymes but also for steroid- and PLP-unrelated proteins such as serum albumin. Albumin gene expression was found to be modulated by vitamin B6 through a novel mechanism that involves inactivation of tissue-specific transcription factors, such as HNF-1 or C/EBP, by direct interaction with PLP in a similar manner to glucocorticoid receptor. Enhancement of albumin gene expression in the liver by an increased supply of amino acids can be explained by elevated binding of HNF-1 and C/EBP to their DNA-binding sites which, in turn, is caused by a decrease in the intracellular level of PLP by the increased amino acid supply. These findings that vitamin B6 acts as a physiological modulator of gene expression add a new dimension to the hitherto recognized function of vitamin B6 as a cofactor of enzyme action.

Antiferromagnetic spin fluctuations above the dome-shaped and full-gap superconducting states of LaFeAsO1-xFx revealed by (75)As-nuclear quadrupole resonance

We report a systematic study by (75)As nuclear-quadrupole resonance in LaFeAsO(1-x)F(x). The antiferromagnetic spin fluctuation found above the magnetic ordering temperature T(N) = 58 K for x = 0.03 persists in the regime 0.04 ≤ x ≤ 0.08, where superconductivity sets in. A dome-shaped x dependence of the superconducting transition temperature T(c) is found, with the highest T(c) = 27 K at x = 0.06, which is realized under significant antiferromagnetic spin fluctuation. With increasing x further, the antiferromagnetic spin fluctuation decreases, and so does T(c). These features resemble closely the cuprates La(2-x)Sr(x)CuO(4). In x = 0.06, the spin-lattice relaxation rate (1/T(1)) below T(c) decreases exponentially down to 0.13T(c), which unambiguously indicates that the energy gaps are fully opened. The temperature variation of 1/T(1) below T(c) is rendered nonexponential for other x by impurity scattering.

Genetic link among Hani, Bulang and other Southeast Asian populations: evidence from HLA -A, -B, -C, -DRB1 genes and haplotypes distribution

Human leucocyte antigen (HLA) genetic characteristic of different ethnic minorities would be useful for tracing the origin of modern human HLA matching in transplantation and disease associations. In this study, we reported HLA-A, -B, -C and -DRB1 alleles and haplotypes in the Bulang and Hani populations of southwestern China using a high-resolution polymerase chain reaction-Luminex (PCR-Luminex) typing method. A total of nine HLA-A, 22 HLA-B, 13 HLA-C and 18 HLA-DRB1 alleles were identified in the Bulang population, and 11 HLA-A, 25 HLA-B, 14 HLA-C and 19 HLA-DRB1 alleles were in the Hani population. Compared with other populations, the predominant A*1101-B*1502-DRB1*1202 haplotype in the Bulang and Hani populations was also common in Jinuo, Wa, Dai, Maonan and Vietnamese populations. The distribution of HLA genes indicate that Bulang and Hani populations belong to the Southeast Asia group and they have maintained their original genetic characteristics and kept a long genetic distance from other populations owing to founder effects and subsequent geographic isolation. In addition, the close relationship among ethnic groups in Yunnan province and the Thai and Vietnamese populations were confirmed, whereas the Mon-Kmer-speaking populations shared other common HLA alleles and haplotypes compared with other linguistic groups.

Power of fecal DNA methylation analysis: Does it lead to development of a noninvasive screening tool for pancreatic cancer?

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Background: The development of noninvasive screening tests is important to reduce mortality from gastrointestinal neoplasia, especially given that there is no noninvasive screening test for pancreatic cancer. We sought to develop such a test by analysis of DNA methylation from exfoliated cancer cells in feces.

Methods: We had reported a novel strategy that uses single-step modification of DNA with sodium bisulfite and fluorescence polymerase chain reaction methodology to measure aberrant methylation in fecal DNA. We increased number of biomarkers from 4 to 8 that were analyzed in 144 fecal samples obtained from a variety of patients, including colorectal tumors, hepatic tumors, and pancreatic tumors.

Results: The assay successfully identified one or more methylated markers in fecal DNA from patients with colorectal cancer, polyps, hepatocellular carcinoma, metastatic colorectal cancer at liver, and pancreatic cancer.

Conclusions: Methylation of 8 biomarkers in fecal DNA is associated with the presence of gastroenterological tumors relative to non-neoplastic conditions. Our fecal DNA methylation assay provides a possible means to noninvasively screen not only for colorectal tumors but also for pancreatic tumors.

No significant financial relationships to disclose.