Peptides
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Dynorphins and beta-endorphin in human plasma were characterized and studied quantitatively using radioimmunoassay, high-performance liquid chromatography (HPLC), and mass spectrometry. Most immunoreactive (ir) dynorphin B and beta-endorphin in human plasma coeluted with authentic peptides in analysis. Dynorphin A was not detected. ⋯ Dynorphin B, alpha-neoendorphin and big dynorphin were virtually not metabolized by plasma proteases under the same conditions. beta-endorphin was processed into beta-endorphin(1-19) and the corresponding C-terminal counterpart beta-endorphin(20-31) at a rate of about 25 pmol/min/microl of plasma. Based on the above data, a reliable strategy was established to measure dynorphin B- and beta-endorphin-ir in human plasma samples. The basal levels in a male control group were 0.99 +/- 0.11 (n = 11) and 16.3 +/- 1.5 (n = 11) fmol/ml plasma, respectively.
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Plasma proenkephalin peptide F and human B cell responses to exercise stress in fit and unfit women.
In vitro studies have connected immune cell function to Peptide F. The primary purpose of this investigation was to examine the responses of plasma Peptide F and epinephrine along with the changes in B cell antibody production in vivo in physically fit and unfit women in response to physical exercise on a cycle ergometer at 60% and 80% of peak oxygen consumption. Seven aerobically fit and eight untrained (i.e., unfit) women between the ages of 18 and 30 volunteered to participate in this investigation. ⋯ The fit group had a significantly higher plasma Peptide F concentration after the 80% exercise intensity along with significantly higher numbers of antibody producing B cells compared to the unfit group. The results of this investigation show that physically fit women have an enhanced secondary response of B cells to a specific antigen under conditions where Peptide F is increased. Such data demonstrate that physical fitness as promoted by the Public Health Service (e.g., Healthy People 2000) influences the underlying hormonal and immune cell responses when challenged by physical exercise stress.
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Comparative Study
Change in substance P in a firearm wound and its significance.
The present study was designed to detect the change of substance P (SP) in firearm wounds and its relationship with wound healing. Twenty two rabbits were randomly divided into two groups, one with firearm wounds created by steel balls shooting rabbits' thighs and another with stab wounds created by knife. The experimental design did not include direct injury to femora major peripheral nerve trunks or blood vessels. ⋯ Meanwhile, wound healing in the firearm wounds was poor compared with that in the stab wounds. The results suggest that the change in SP in firearm wounds differs from that in cold weapon wounds as a result of the presence of indirect injuries to major peripheral nerve trunks created by laceration shock wave and cavity effects, and SP in vivo may participate in wound healing as a growth factor. Therefore, the improvement of neuropeptide metabolism in firearm wound may be an important measure for accelerating wound healing.
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The role of neuropeptide FF (NPFF) in the modulation of spinal nociception was studied in rats with carrageenan inflammation in the hind paw. Normally no NPFF-ir neuronal cell bodies are found in the spinal cord. During inflammation NPFF-neurons were seen in an area receiving innervation from the inflamed hind limb, but in rats pretreated with morphine no NPFF-ir neurons were found. ⋯ Morphine produced significant antinociception in both tests in the inflamed paw, but the effect was not modified by NPFF. These findings differ from the effects of intrathecal administration of NPFF and opioids in acute thermal tests when no inflammation is present. The role of NPFF in the modulation of nociception in the spinal cord may be markedly changed during acute inflammation.
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Diabetes is associated with altered autonomic activity, and both the peripheral and central nervous content of NPY is altered in diabetes suggesting that part of the cardiovascular dysfunction of diabetes may be associated with altered responses to NPY. We evaluated the mean arterial pressure (MAP), heart rate (HR) and regional blood flow (BF) in response to NPY in normal and diabetic rats. Male Wistar rats were made diabetic using streptozotocin and maintained without insulin treatment for 28-30 days. ⋯ When comparing diabetic response to NPY to normals we noted that the MAP response was less in the diabetic, but the HR and regional BF were not different. The vascular conductances in response to NPY were attenuated in the diabetic vessels especially the iliac and superior mesenteric. We conclude that systemic NPY increases MAP as a result of decreased vascular conductance and this vasopressive effect of NPY is diminished in diabetics.