Development of time-resolved immunofluorometric assays for vascular endothelial growth factor and application on plasma of patients with gastric tumours.

A highly sensitive and accurate time-resolved immunofluorometric assay (TR-IFMA) has been developed, for the first time, to measure plasma vascular endothelial growth factor (VEGF) in patients with gastric tumours. A monoclonal anti-hVEGF antibody and a biotinylated anti-hVEGF antibody were used to develop a non-competitive 'sandwich'-type assay. Fluorescence can be measured by a time-resolved fluorometer after binding of europium (Eu)(3+)-labelled streptavidin to the biotinylated immunoglobulin. Plasma VEGF concentrations were measured by TR-IFMA in 92 healthy controls, in 36 benign stomach disease patients and in 92 gastric cancer patients before surgery. The association between plasma VEGF levels and clinicopathological features was evaluated. A standard curve for VEGF TR-IFMA has been developed with good sensitivity (0.37 pg/ml). Accuracy studies, specificity, parallelism and precision data were determined and all were found to be satisfactory. The validity of the VEGF assay was confirmed by the good correlation between the results obtained by TR-IFMA and commercial enzyme-linked immunosorbent assay (ELISA) (ELISA result = 1.862 + 0.953 (TR-IFMA result), r = 0.944]. The plasma levels of VEGF are higher in gastric cancer patients than in healthy controls. VEGF levels were associated significantly with the presence of distant metastases, as well as invasion depth of the tumour and tumour stage, but not with tumour location, tumour histology, differentiation or the presence of lymph node metastases. At the cut-off of 217.79 pg/ml, the diagnostic sensitivity, specificity and accuracy of the TR-IFMA were 40.2%, 93.7% and 69.9%, respectively. A highly sensitive and reliable TR-IFMA for VEGF has been developed. The determination of plasma VEGF levels may be clinically useful.

Hyaluronic acid hydrogel as Nogo-66 receptor antibody delivery system for the repairing of injured rat brain: in vitro.

Nogo-66 and NgR are important receptors inhibiting neuronal regeneration and therefore are targets for treating CNS injury. Antagonists of this receptor including blocking antibodies are potential therapeutic agents for CNS axonal injuries such as spinal cord and brain trauma. A new antibody (IgG) releasing system has been developed by covalently attaching IgG to the biodegradable hyaluronic acid (HA) hydrogel via the hydrolytically unstable hydrazone linkage, aiming to deliver the antibody of CNS regeneration inhibitors to the injured brain. In this paper we describe the synthesis, physico-chemical characteristics and test results of biological activity of antibody released from hyluronic acid hydrogel. To form the conjugates the antibody is attached to the polymer backbone using a condensation reaction between aldehyde group of the antibody and hydrazide group of the HA hydrogel. Furthermore, pH sensitive linkage-hydrozone has been formed between hydrogel and antibody. The amount of conjugated antibodies can reach 135 microg antibody/mg hydrogel in the dry state. At low pH, the antibodies released quite fast. However, the antibodies released much slower in neutral and alkaline environment. The bioactivity of antibody released from hydrogel was retained as demonstrated by indirect immunofluorescence technique.

The effect of calcitonin gene-related peptide on ischemic reperfusion-induced arrhythmias in rats.

Thirty-six wistar rats (150-250 g body weight) were randomly divided into two groups. There were equal numbers of male and female rats in each group. Each group of rats was given either 0.5 ml normal saline or calcitonin gene-related peptide (CGRP, 20 micrograms/kg dissolved in 0.5 ml normal saline) intravenously within 5 min. Coronary arteries of these rats were occluded 5 min after administration. The coronary artery was then released from ligation 5 min later. The heart beat of all rats was monitored for 30 min. An electrocardiogram was recorded using limb leads and below-xiphoid leads. There was no ischemic reperfusion-induced arrhythmia in the first minute of reperfusion in CGRP group, while 13 rats occurred ischemic reperfusion-induced arrhythmia (ventricular tachycardia and fibrillation) in the normal saline group (P < 0.05). Average onset time of ischemic reperfusion-induced arrhythmia was 377.5 +/- 141.0 s/sim. In the CGRP group, compared with 42.7 +/- 55.4 s/sim. for the normal saline group (P < 0.01). The duration of ischemic reperfusion-induced arrhythmia was 15.0 +/- 30.6 s/sim. In the CGRP group compared with 104.4 +/- 143.8 s/sim. in the normal group (P < 0.05). There was no death in the CGRP group, but six rats in the normal saline group died (P < 0.05). The results showed that CGRP could reduce and delay the occurrence of ischemic reperfusion-induced arrhythmia such as ventricular tachycardia and fibrillation, especially in the early period, and decrease the mortality. The mechanism is not clear and needs to be studied further.

[Increased plasma endothelin-1 concentration in acute cerebral infarction and its clinical significance].

In acute cerebral ischemia there are severe damages of endothelium recognized as the stimuli for secretion of endothelin-1, that is a endothelium-derived peptide and seems to be the most potent vasoconstrictor known. The goal of this study is to measure plasma endothelin-1 level in patients with cerebral infarction and determine the relationship between endothelin-1 and ischemic stroke. Plasma level of endothelin-1 was measured in 21 consecutive patients. The measurement was performed 3 times at different stages of stroke. There was a marked increase in plasma endothelin-1 level in the patients and the elevation lasted the entire acute and subacute stage of stroke. There was a correlation between the peptide concentration and infarct volume (r = 0.665, P < 0.01). The result suggests that endothelin-1 plays an important role in the regulation of brain circulation. Apparent and lasting increase in plasma level of endothelin-1 is associated with cerebral ischemia and infarction. The peptide seems to be involved in the pathophysiology of acute cerebral ischemia and have a deleterious effect in the evolution of cerebral infarction.

Increased plasma endothelin-1 concentration in patients with acute cerebral infarction and actions of endothelin-1 on pial arterioles of rat.

In acute cerebral ischemia there are severe damages of endothelium which have been recognized as the stimuli to secrete endothelin-1, an endothelium-derived peptide and the most potent vasoconstrictor ever known. This study was to measure plasma endothelin-1 level in patients with cerebral infarction and explore the relationship between endothelin-1 and ischemic stroke. The possible involvement of endothelin-1 in local regulation of cerebral arterioles was also investigated. Plasma levels of endothelin-1 were measured by radioimmunoassay in 21 patients. Using a micro-video system, the endothelin-1 actions were also observed on rat pial arterioles in vivo, and with incomplete cerebral ischemia model (rat), effect of ischemia affects the endothelin-1 action. There was a marked increase in plasma endothelin-1 level in the patients and the elevation persisted during the acute and subacute period of stroke. There was a positive correlation between the peptide concentration and infarct size (r = 0.655, P < 0.01). In rats, endothelin-1 (dose range: 10(-10) mole/L-10(-7) mole/L) induced a dose-dependent arteriole contraction after subdural administration. Arteriole calibers were decreased by 27.7% +/- 3.8% (10(-9) mole/L), 46.8% +/- 4.9% (10(-8) mole/L) and 78.5% +/- 4.7% (10(-7) mole/L), respectively. Cerebral ischemia significantly enhanced the action of endothelin-1 (96.4% +/- 7.2% vs 58.2% +/- 6.8%). Endothelin-1 plays an important role in regulating local circulation of ischemic brain. The notable and lasting increase in plasma level of endothelin-1 are associated with cerebral ischemia and infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

[Synthesis of porcine brain natriuretic peptide (BNP-26) and an analog].

The porcine brain natriuretic peptide (BNP-26) and its analog, (Mpr4,D-Ala6,13) BNP(4-24)-NH2, were synthesized by solid phase method employing the Boc strategy. After HF cleavage to remove the protected groups, the crude linear peptide was air-oxidized under alkaline conditions to form the disulfide bridge. The synthetic peptides, purified by gel filtration and HPLC, were proved to have pharmacological spectra very similar to that of natural BNP such as natriuretic/diuretic, hypotensive and vaso-relaxant activities.

The effect of calcitonin gene-related peptide on arrhythmia caused by adenosine diphosphate and desacetyldigilanide-C in rats.

We investigated the effect of calcitonin gene-related peptide on the arrhythmia induced by two drugs in rats. The results of our experiments have proved that calcitonin gene-related peptide could reduce the degree of atrioventricular block, protect against the attacks of sinus standstill and ventricular fibrillation produced by adenosine diphosphate, and improve restoration of sinus rhythm. Calcitonin gene-related peptide was able to eliminate sinus standstill and ventricular fibrillation resulting from administration of desacetyldigilanide-C. These results demonstrate that calcitonin gene-related peptide has strong antiarrhythmic effects in experimental animals.

Molecular forms of beta-endorphin in ACTH/LPH hypersecretion syndromes in man.

beta-Endorphin31, beta-endorphin1-27, and their alpha-N-acetyl derivatives were specifically separated by ion exchange chromatography from human beta-endorphin-'like' material obtained from extracts and culture media of corticotropic adenomas and extract of plasma from Nelson's syndrome and ectopic ACTH/LPH syndrome. Studies with pituitary-derived materials have shown that human beta-endorphin1-31 was the major form and human beta-endorphin1-27 a minor form. No other peptide was detected. In plasma from the ectopic ACTH-LPH syndrome human beta-endorphin1-31 was the only detected peptide. In 2 such patients with chronic elevation of human beta-endorphin1-31 the pain sensitivity threshold was normal and naloxone induced no modification, suggesting that circulatory human beta-endorphin has no effect on the central nervous system.

Essential fatty acid deficiency: metabolism of 20:3(n-9) and 22:3(n-9) of major phosphoglycerides in subcellular fractions of developing and mature mouse brain.

Essential fatty acid deficiency was initiated in young and mature mice. The metabolism of 20:3(n-9) and 22:3(n-9) in brain subcellular fractions was followed after the mice were switched from the deficient diet to a corn oil supplemented diet. After switching to the supplemented diet, the proportions of (n-9) polyunsaturated fatty acids in brain in both groups of mice decreased with time. The rate of disappearance of (n-9) polyunsaturated fatty acids was faster in the young groups than in the mature group. In the developing mice, the half-linves of the (n-9) polyunsaturated fatty acids in the total ethanolamine phosphoglycerides of brain microsomal, synaptosomal, and myelin fractions were 3, 10, and 15 days respectively. In the mature group, the half-lives for 20:3(n-9) in diacyl-glycerophosphorylethanolamine of microsome, synaptosome, and myelin fractions were 8-10, 10, and 22 days, respectively; and the half-lives for 22:3(n-9) in alkenylacyl-glycerophosphorylethanolamine of the same subcellular fractions were 8-12, 28, and rate of disappearance of 20:3(n-9) in brain was faster in the diacyl-glycerophosphorylethanolamine than in the alkenylacyl-glycerophosphorylethanolamine. These results demonstrate that the metabolism of (n-9) polyunsaturated fatty acid in brain phosphoglycerides during recovery from essential fatty acid deficiency not only varies with age, but also depends upon individual phosphoglycerides present in each subcellular fraction.