N,N'-ethylene-di-L-cysteine (EC) complexes of Ga(III) and In(III): molecular modeling, thermodynamic stability and in vivo studies

There are several reports in the literature on the evaluation of chelates containing two nitrogens and two sulfurs (N2S2) as four coordinate ligands (in solution) for gallium and indium radiopharmaceuticals. No thermodynamic stability constants of these ligands were reported, and the stability of these complexes in vivo has been questioned. L,L-Ethylenedicysteine (EC) is a N2S2 ligand that also contains two carboxylic acid moieties for complexation of Ga(III) and In(III) in a hexacoordinate environment. The stability constants of Ga- and In-EC have been determined by potentiometric methods. The stability of In-EC was found to be greater than that of Ga-EC, with stability constants (log K's) of 33.0 and 31.5, respectively. A molecular mechanics evaluation of the Ga- and In-EC complexes support the thermodynamic results. 67Ga- and 111In-labeled complexes of EC were prepared and analyzed by thin layer chromatography and electrophoresis. Both complexes were evaluated in biodistribution studies in normal Sprague-Dawley rats. 111In-EC cleared rapidly through the hepatobiliary system, whereas 67Ga-EC remained in the liver at 1 h post-injection. Although 67Ga-EC was retained in the liver, suggesting instability of the complex in vivo. 67Ga-EC was stable in rat plasma in vivo at 2 h post-injection. Because of the high thermodynamic and in vivo stability of In-EC, derivatives of EC may have applications as bifunctional chelates for 111In-labeled proteins and peptides. More lipophilic analogues of 68Ga-EC may also have potential as myocardial PET imaging agents.

Effects of intrathecal naloxone and atropine on the nociceptive suppression induced by norepinephrine and serotonin at the spinal level in rats

The interrelations among norepinephrine (NE), serotonin (5-HT), opiate-like substances (OLS), and acetylcholine (ACh) were investigated by using electrophysiological method combining with intrathecal (i.t.) injection. The results show that: (1) pretreatment with i.t. naloxone (Nal) completely reversed the NE-induced suppression of nociceptive discharges in parafascicular (PF) neurons, but partially reversed that of induced by i.t. 5-HT; (2) pretreatment with i.t. atropine (Atr) completely reversed the suppression induced by either NE or 5-HT. The results suggest that OLS may act as a necessary mediator for NE-induced suppression on the spinal transmission of nociceptive inputs, while it is only partially involved in the 5-HT-induced suppression, and moreover, that endogenous ACh is necessary for the performance of nociceptive suppression induced by either spinal NE or 5-HT administration.

Transplantation of cholinergic-rich spinal tissue from spontaneously aborted human fetuses into a rodent model of Alzheimer's disease

The results from this study provided the first piece of evidence that intrahippocampal transplants of cholinergic-rich spinal grafts derived from a human fetus can ameliorate the performance of fornix lesioned rats in both spatial reference memory and spatial navigation tasks. Although many questions remain to be answered, these results point to the therapeutic potential of human fetus-derived cholinergic-rich grafts in treating spatial memory impairments.

[Efficacy of Phyllanthus spp. in treating patients with chronic hepatitis B]

The efficacy of Phyllanthus amarus produced in india, P. niruri gathered from hainan province and P. urinaria from henan province was assessed in a total of 88 cases of chronic hepatitis B with 11.42 and 35 each. It was shown that P. urinaria had the effect of seroconversion on HBeAg from positive to negative as well as on HBeAb from negative to positive, while the other two herbs had not. In addition none of these three herbs had similar effect on HBsAg.

Protective effect of tetramethylpyrazine against damages of aortic endothelial cells elicited by low-density lipoproteins

Effects of tetramethylpyrazine (TMP) on endothelial cells damaged by low-density lipoproteins (LDL) were investigated. When endothelial cells were incubated with LDL (1.5 mg protein.ml-1) the level of malondialdehyde (MDA) was increased and the activity of superoxide dismutase (SOD) was inhibited, and levels of cGMP and epoprostenol were decreased. TMP at concentrations of both 20 and 150 mg.L-1 nullified the inhibition of SOD activity and the reduction of cGMP and epoprostenol content elicited by LDL. However, the elevation of MDA content induced by LDL was negated by TMP only at 150 mg.L-1. TMP also caused a reduction in MDA content and an increase of epoprostenol level in normal endothelial cells. This study suggests that TMP protects endothelial cells against damages elicited by LDL and that the protection of TMP might be due to reduction in lipid peroxidation through stimulation of production and/or release of epoprostenol.

[Changes in soluble interleukin-2 receptor and its significance in nephrotic syndrome]

Serum and urine soluble interleukin-2 receptor (SIL-2R) levels were determined with ELISA method in 36 cases of nephrotic syndrome in order to investigate the significance of the change of SIL-2R level. The results showed the values in nephrotic stage group (n = 22) exceeded those in nephrotic stage remission group (n = 14, P < 0.01) and those in healthy controls (n = 20, P < 0.01). However, there was no difference of SIL-2R values either in serum or urine between nephrotic stage remission group and healthy controls (P > 0.05). Serum SIL-2R values were correlated with those of serum creatinine (r = 0.44, P < 0.01) and urine SIL-2R values were correlated with those of urine protein excretion (r = 0.48, P < 0.01). The study suggests that increased concentration of SIL-2R can serve as an indicator of nephrotic syndrome activation and/or exacerbation of renal dysfunction.

Investigation on inactivated epidemic hemorrhagic fever tissue culture vaccine in humans

From 1988 to 1992, 2479 volunteers were immunized by inactivated Meriones unguiculatus kidney cell (MUKC) vaccine. Their seroconversion rates of neutralizing antibody were about 90% after 3 doses of the vaccine. No side effects were found. The vaccine stored for 14 months at 4 degrees C still had good immunogenicity. It was shown that the vaccine was safe, effective and stable. Detailed observation was made in 75 volunteers. The results showed that the seroconversion rate by plaque reduction neutralization test in 3 doses group was higher than that in 2 doses group; but the results by reversed passive hemagglutination (RPHI), immunofluorescence assay (IFA) and ELISA were similar. Different immunization procedures (3 x 1 ml during 28 days or 3 x 1 ml during 60 days), injection routes (im or sc) and vaccine forms (containing adjuvants or not) showed no significant difference. If secondary immunization (one dose) was given one year after primary immunization, geometric mean titre of the neutralizing antibody was two fold higher than that after primary immunization.

Mechanisms of relaxation by pyrogallol and methylthioninium chloride in perfused rat mesenteric artery

In perfused rat mesenteric arteries without endothelium, pyrogallol (Pyr) or methylthioninium chloride (methylene blue, Met) produced a concentration-dependent relaxation. Superoxide dismutase abolished inhibition by Pyr, but not Met, of vasoconstrictor responses to transmural nerve stimulation (TNS). Neither catalase nor deferoxamine had any effect on vasodilator responses to Pyr or Met. Vasodilator responses to Pyr were unaltered by N omega-nitro-L-arginine methyl ester (L-NAME), indomethacin, or capsaicin. Similarly, the relaxing effect of Met was unaffected by indomethacin or capsaicin. These findings suggest that vasodilator responses to Pyr may be due to endothelial-independent generation of superoxide anion. In contrast the relaxation produced by Met appears to be due to a direct action on vascular smooth muscle independent of superoxide anion generation.

Protection of l-arginine against oxygen free radicals-injured rabbit aortic endothelium

This study was to investigate the protective effect of l-arginine, a precursor of endothelium-derived relaxing factor (EDRF), against damages due to endogenous or exogenous oxygen free radicals (OFR) on the aortic endothelium. The superfusion cascade bioassay of rabbit thoracic aorta was used. Endogenous OFR were generated by diethyldithiocarbamate (DETC) to deplete the cytosolic Zn-Cu form of superoxide dismutase (SOD). Exogenous OFR were generated by electrolysis of Krebs' solution. Acetylcholine (ACh) was infused through the donor aortic segment and relaxation of detector aortic ring was used as an indicator of the release of EDRF. The content of malondialdehyde (MDA) in the donor aorta was assayed biochemically. Both DETC and electrolysis inhibited vasodilator responses to ACh and increased MDA content in the aortic segment. Inhibition of DETC was abolished by exogenous SOD. l-Arginine improved impairment of endothelium-dependent relaxation and reduced elevation of MDA content by DETC or electrolysis. These results suggest that l-arginine presents a protective effect of endothelium against damage due to endogenous or exogenous OFR, and that the protective effect of l-arginine may be correlated with reduction in lipid peroxidation.

Prostacyclin analog (cicaprost) protects against damage by hydrogen peroxide to rabbit cardiac sarcoplasmic reticulum

The membrane fluidity of the cardiac sarcoplasmic reticulum in rabbit was monitored by measuring changes in steady-state fluorescence anisotropy (rs) using diphenylhexatriene as a probe. The Ca(2+)-ATPase activity of the sarcoplasmic reticulum was measured by assaying the amount of inorganic phosphate released from ATP. Hydrogen peroxide caused damage to the sarcoplasmic reticulum, as reflected by decreases in membrane fluidity and Ca(2+)-ATPase activity. The damage caused by hydrogen peroxide was completely prevented by 20 micrograms/ml catalase. Cicaprost (240 nM) provided an effective protection against injury to the sarcoplasmic reticulum caused by exposure to hydrogen peroxide. The rs value was significantly decreased from 0.154 +/- 0.014 to 0.122 +/- 0.005 (p < 0.01). Ca(2+)-ATPase activity was increased from 3.1 +/- 1.31 to 18.87 +/- 2.11 microM phosphate/mg protein/hour (p < 0.01). The protection given by cicaprost was dose dependent. We conclude that cicaprost protects against damage produced by hydrogen peroxide in cardiac sarcoplasmic reticulum in the rabbit. The mechanism of the effect of cicaprost remains to be elucidated.

Increase of an endogenous inhibitor of nitric oxide synthesis in serum of high cholesterol fed rabbits

In the present study, the concentration of NG,NG-dimethylarginine (DMA), an endogenous inhibitor of nitric oxide synthesis, was measured with high-performance liquid chromatography, and the effect of hypercholesterolemia on DMA level was investigated in the high fat, high cholesterol fed rabbit. After 6 weeks on a high fat, high cholesterol diet, serum total cholesterol, triglycerides, and lipid peroxides were increased, and atherosclerosis was shown by means of morphological examination. In these rabbits with atherosclerosis, serum level of DMA was significantly raised, while serum creatine level remained normal. This study suggests that chronic hypercholesteremia may stimulate DMA production through elevation of lipid peroxides. The present results implicate endogenous DMA as a contributor to the development of atherosclerosis.

Presence of endothelium masks direct vasodilator effects of pyrogallol and methylthioninium chloride in perfused rat mesenteric artery

In the perfused rat mesenteric artery vasoconstrictor responses to transmural nerve stimulation (TNS) were enhanced by pyrogallol (Pyr) 0.1 mmol.L-1 or methylthioninium chloride (Met) 0.01 mmol.L-1. But the duration of the effect of Pyr was brief, while the effect of Met remained stable. Met, but not Pyr, slightly increased the basal level of perfusion pressure. Contractile responses to the alpha adrenergic agonist methoxamine were also potentiated by both Pyr and Met, and in both cases their effects persisted as long as Pyr or Met was present. Superoxide dismutase (SOD) abolished or inhibited the potentiation produced by Pyr or Met. Both Pyr and Met inhibited the vasodilation produced by acetylcholine (ACh). However, after blockade of endothelial function both Pyr and Met inhibited vasoconstrictor responses to TNS in the presence of N omega-nitro-L-arginine methyl ester (L-NAME) 0.1 mmol.L-1, an inhibitor of nitric oxide synthesis, or removal of endothelium. After removal of endothelium both Pyr and Met produced vasodilator responses in a concentration-dependent manner. These results suggest that the ability of both Pyr and Met to potentiate contractile responses and inhibit vasodilator responses to ACh is due to generation of superoxide anion, and that the actions of Met may also involve direct inactivation of guanylate cyclase. The present study also suggests that both Pyr and Met have direct relaxing effects on vascular smooth muscle, effects which are masked by enhancing actions in the presence of endothelium.

[The characters on histopathological changes in dental fluorosis]

The microradiography SEM and TEM were used ton observe histopathological changes in dental fluorasis with various degrees in this study.The characters of histopathological changes of dental fluorasis are:(1) the lesios appear in exterior layer of enamel,not excess one third enamel.(2)the future of the lesion is enamel-hypoplasia,enamel rods were hypomineralized.the space among enamel rods widen and form some cavities.There are a lot of spaces in intercrystlines.Many micropores and injures exhibit on enamel surface.(3)the clinic severe degree of lesion is similar to the histopathological changes.It could be indicated using the Dean's and the TF index.

[Nephrocalcinosis and clinical significance in early chronic renal disease]

Kidney tissue calcium content from 33 diagnostic human renal biopsies was measured to assess tissue calcium concentration early in the course of human renal disease. Renal calcium content was correlated significantly with serum creatinine (r = 0.71, P < 0.001), serum phosphate (r = 0.64, P < 0.001), and serum Ca x P product (r = 0.66, P < 0.001), but not with serum calcium (r = -0.17, P > 0.05). Threefold greater calcium content was measured in biopsied tissue than in normal renal tissue (315 +/- 169 vs 69 +/- 17 mg/kg renal tissue, P < 0.001). The mean level of serum phosphate and Ca x P product was higher in the patients with significant renal function impairment (Ser > 115 mumol/L) than in patients with normal renal function (1.76 +/- 0.33 mmol/L vs 1.29 +/- 0.18 mmol/L, P < 0.001; 43 +/- 4.7 vs 33 +/- 4.5 mmol 2/L2, P < 0.001, respectively). The mean serum calcium levels were not different in the two groups (1.97 +/- 0.24 mmol/L vs 2.07 +/- 0.16 mmol/L, P > 0.05). The results suggest that renal calcium deposition begins early in the course of various renal diseases, and hence may accelerate progression of chronic renal failure the severity of renal calcium deposition is correlated with hyperphosphatemia and with the level of renal impairment. Dietary phosphate restriction may be necessary early in the course of renal disease.

The regulatory effect of bradykinin on the actions of sensory nerves in the perfused rat mesentery is mediated by nitric oxide

In the perfused rat mesentery, when adrenergic nerves were blocked with guanethidine and vascular smooth muscle tone was increased with methoxamine, transmural field stimulation caused a dilator response. Bradykinin significantly suppressed vasodilator responses to a transmural field stimulation in a concentration-dependent manner. After pretreatment with saponin to damage endothelial cells, bradykinin still suppressed vasodilator responses to transmural field stimulation. The effect of bradykinin was unaltered by indomethacin. N omega-Nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis, abolished the inhibition of vasodilator responses to transmural field stimulation elicited by bradykinin. However, in the presence of L-arginine and L-NAME the inhibitory effect of bradykinin reappeared. Furthermore, methylene blue itself caused potentiation of vasodilator responses to transmural field stimulation and reversed the effect of bradykinin. These findings suggest that bradykinin can produce an inhibitory modulation of the actions of sensory nerves in the perfused rat mesentery and that the effect of bradykinin may be mediated by nitric oxide released from non-adrenergic, non-cholinergic nerves.

Effects of hydrogen peroxide on membrane fluidity and Ca(2+)-transporting ATPase activity of rabbit myocardial sarcoplasmic reticulum

This study was to investigate the effects of hydrogen peroxide on membrane fluidity and Ca(2+)-ATPase activity of rabbit myocardial sarcoplasmic reticulum (SR). The membrane fluidity of SR was monitored by measuring the changes in the steady state fluorescence anisotropies (rs) using diphenylhexatriene as a probe. The Ca(2+)-ATPase activity was determined by assaying the amount of inorganic phosphate (Pi) released from ATP. It was found that the membrane fluidity (rs: 0.154 +/- 0.014 vs 0.113 +/- 0.010, P < 0.01) and Ca(2+)-ATPase activity (3.1 +/- 1.3 vs 25.3 +/- 2.4 mumol Pi.h-1/mg protein, P < 0.01) were reduced in SR exposed to H2O2 (2 mmol.L-1) for 40 min. Catalase 20 micrograms.ml-1 completely prevented the SR damages caused by H2O2. H2O2 jeopardized the SR in a concentration- and time-dependent manner as measured by changes in rs values and Ca(2+)-ATPase activities, which were negatively correlated (r = 0.981, P < 0.01). These results suggest that H2O2 produces dysfunctions of the rabbit myocardial SR, and that the alteration of membrane fluidity may be one of the mechanisms responsible for the decrease of Ca(2+)-ATPase activity.

Nitric oxide modulates responses to sensory nerve activation of the perfused rat mesentery

The modulatory actions of nitric oxide on sensory nerves were investigated on dilator responses of the perfused rat mesentery to transmural nerve stimulation. N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis, caused a significant augmentation of vasodilator responses to transmural nerve stimulation, an effect which was abolished by L-arginine. L-NAME had no effect on vasodilator responses to exogenous calcitonin gene-related peptide. In preparations without endothelium L-NAME still caused potentiation of vasodilator responses to transmural nerve stimulation. Methylene blue, an inhibitor of guanylate cyclase, also significantly enhanced vasodilator responses to transmural nerve stimulation. After pretreatment with diethyldithiocarbamate to inhibit superoxide dismutase, vasodilator responses to transmural nerve stimulation were also potentiated. This response was abolished by exogenous superoxide dismutase. These findings suggest that endogenous nitric oxide modulates, in an inhibitory fashion, the actions of sensory nerves in the rat mesentery. The results also suggest that endogenous superoxide dismutase may participate in the regulation of the actions of sensory nerves via control of cellular superoxide anion level.

[The relationship between metastatic phenotype and steady expression of BGC-Ha-ras oncogene from metastasis cell lines in nude mice (abstract)]

NIH/3T3 cells transformed by activated BGC-Ha-ras (6.6 kb) with a point mutation at codon 12 were able to induce tumor in nude mice with lung metastasis. The metastatic phenotype seemed stable in vivo metastasis assay. After two round subculture of the successively induced metastasis foci, two cell lines, GCM-1/3T3 and GCM-2/3T3, were established. In Southern blot analysis it was found that the bands from GCM-1/3T3 and GCM-2/3T3 were the same. Based on Southern analysis and polymerase chain reaction-restriction fragment length polymorphism (PCR-RPLF), it was proved that the activated c-Ha-ras (6.6 kb) existed all along in the genomes of the transformed and metastatic culture cells. Amplification and over-expression of activated c-Ha-ras were shown by DNA and RNA dot blot hybridization in transformed and metastatic culture cells. The metastatic phenotype might be related to the existence and steady expression of the point mutated ras.

Intrahippocampal grafts of cholinergic-rich striatal tissue ameliorate spatial memory deficits in rats with fornix lesions

Previous studies have shown that cholinergic grafts derived from the medial septal nucleus are capable of restoring behavioral function in rats with lesions that sever the cholinergic inputs to the hippocampal formation. In this study, we demonstrate that intrahippocampal grafts of cholinergic-rich striatal tissue also ameliorate spatial memory deficits of rats with fornix lesions. We also found that atropine administration dramatically disrupted spatial navigation performance of rats with striatal grafts and control rats, thus suggesting that the striatal graft effects are mediated by cholinergic mechanisms of action. Measurements of high affinity choline uptake (HACU) and muscarinic receptor binding revealed that intrahippocampal striatal grafts increased HACU and normalized muscarinic receptor binding in animals with fornix lesions. Regression analyses demonstrated significant correlations between the amelioration of spatial memory deficits and hippocampal HACU and receptor binding. We conclude that intrahippocampal grafts of cholinergic-rich striatal tissue can ameliorate spatial memory deficits and that this amelioration is associated with the reinstatement of functional cholinergic terminations.

Effect of endothelium on the actions of sympathetic and sensory nerves in the perfused rat mesentery

We and others have previously demonstrated that pretreatment with capsaicin produces an augmentation of vasoconstrictor responses to transmural nerve stimulation. In the present study, removal of endothelium by saponin or inhibition of nitric oxide synthesis by N omega-nitro-L-arginine methyl ester produced an augmentation of vasoconstrictor responses to transmural nerve stimulation, responses which were further potentiated after treatment with capsaicin to desensitize sensory nerves. Capsaicin treatment decreased vasodilator responses to acetylcholine, but only at low acetylcholine concentrations. Potentiation by capsaicin of vasoconstrictor responses to transmural nerve stimulation was not affected by indomethacin. In the presence of guanethidine and methoxamine, transmural nerve stimulation caused vasodilator responses in the perfused rat mesentery. These responses were unaffected by removal of endothelium, as were vasodilator responses to exogenous calcitonin gene-related peptide (CGRP). In contrast, substance P did not produce any relaxation in the methoxamine-contracted mesentery. This study suggests that facilitation of vasoconstrictor responses to transmural nerve stimulation after capsaicin treatment primarily reflects inhibition of sensory nerve effects resulting in an increase of sympathetic vasoconstrictor actions. The present results also suggest that vasodilator responses to sensory nerve activation or exogenous CGRP are endothelium-independent and that substance P does not significantly contribute to modulation of vascular tone in the rat mesentery.

Analogous copper(I) coordination in metallothionein from yeast and the separate domains of the mammalian protein

The three-dimensional structures of both vertebrate Cu12-metallothionein (class 1) and yeast Cu8-thionein (class 2) are still unknown. The different copper:protein stoichiometry compared with that of the (ZnCd)7-metallothioneins was expected to alter the metal-thiolate cluster structure considerably. In order to avoid possible domain interactions in the hepatic rat metallothionein, separate chemically synthesized alpha- and beta-domains were used rather than the apoprotein. Apo yeast thionein, and the alpha- and beta-domains of rat liver metallothionein-2 were reconstituted by Cu(I) titration. Reconstitution steps were monitored using spectroscopic methods including luminescence emission and circular dichroism. Upon UV irradiation a linear increase in intensity of the orange-red luminescence was observed near 600 nm up to 6 Cu eq using either compound regardless of the different cysteine sulfer content (yeast thionein 12S, alpha-domain 11S, beta-domain 9S). The characteristic dichroic properties of the yeast copper-protein between 240 and 400 nm were in good agreement with those of the respective class 1 metallothionein domains. All observed Cotton bands were of similar shape and appeared in the same wavelength regions. However, the molar ellipticities were less pronounced in the alpha- and beta-fragments employed. There appears to be a striking similarity between the oligonuclear Cu(I) binding centers in all metallothionein species.

Effects of intrathecal monoamine antagonists and naloxone on the descending inhibition of the spinal transmission of noxious input in rats: study with a new experimental model

An electrophysiological model has been developed to explore the transmitters and their relationships in the descending control of spinal transmission of noxious inputs. Nociceptive discharges were recorded extracellularly in parafascicular (Pf) neurons, and the caudal stump of longitudinally isolated dorsal half of the lower thoracic spinal cord was stimulated to simulate the descending volleys coming from the supraspinal structures. Nociceptive discharges in 34 Pf cells were markedly suppressed (83.2 +/- 13.9%) by the preceding spinal stimulation. Phentolamine, methysergide and naloxone were separately administered with random sequence in each of 25 cells by an intrathecal route to observe if the descending inhibition could be blocked by these drugs. The results suggested that in the dorsal spinal cord there exist at least two neurochemically different descending inhibitory fiber systems which comprise either the long descending adrenergic or serotonergic fibers and, most of the adrenergic fibers are succeeded by a propriospinal opioidergic neuron while a few of the serotonergic fibers have such a succession.

Effect of opioid receptor antagonists on vasodilator nerve actions in the perfused rat mesentery

Our previous work suggests that opioid peptides modulate sensory nerves in the perfused rat mesentery. Therefore we tested the hypothesis that opioids are involved in the ongoing regulation of sensory nerve activity using selective opioid receptor antagonists. In the presence of guanethidine and methoxamine, transmural nerve stimulation caused a vasodilator response which was potentiated significantly by naloxone (3 x 10(-7) M). However, naloxone did not affect vasodilator responses to exogenous calcitonin gene related peptide. IC1 174.864 (3 x 10(-7) M), a selective delta receptor antagonist, had no effect on vasodilator responses to transmural nerve stimulation. In contrast CTOP (D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Phe-Thr-NH2) (3 x 10(-7) M), a selective mu receptor antagonist, significantly inhibited vasodilator responses to transmural nerve stimulation, effects which were abolished by naloxone treatment. In preparations pretreated with beta-FNA (beta-funaltrexamine HCl), an irreversible mu receptor antagonist, naloxone no longer potentiated vasodilator responses to transmural nerve stimulation. These results suggest that potentiation of vasodilator responses to transmural nerve stimulation by naloxone may be due to blockade of mu receptors, resulting in a reduced inhibitory modulation by endogenous opioids. These findings support the contention that prejunctional opioid receptors on sensory nerves may play a role in modulating activity of the cardiovascular system.

Immunization strategies for the production of rat monoclonal anti-idiotope antibodies

Anti-idiotypic antibodies are powerful reagents for the study of immunoregulation, and have potential interest as vaccines against tumors and infectious diseases. Three immunization strategies for the production of rat monoclonal anti-idiotope antibodies have been compared in this paper. Male Wistar rats were immunized i.p. and at multiple subcutaneous sites with 750 micrograms of purified monoclonal antibody against Plasmodium falciparum for three times and subsequently boosted by (1) intraperitoneal injection with 750 micrograms of the immunogen, (2) intravenous inoculation with 400 micrograms of the IgG, and (3) intrasplenic immunization with 200 micrograms of the idiotype. With the intraperitoneal boost method, the frequency of hybrids with anti-idiotope activity was 0.3-0.9% with 62.8-85.2% of the seeded wells containing hybrids. In the intravenous boost group, the percentage of hybrids demonstrating anti-idiotope activity increased to 11.0-13.3% with 80.2-97.9% of the hybrid efficiency. When immunized by the intrasplenic boost route, the frequency of anti-idiotope hybrids generated rose to 12.9-16.4% with 82.3-96.6% of the hybrid efficiency. There was no obvious effect of the boost immunizing methods on the generation of rat monoclonal anti-mouse IgG antibodies. These results indicated that the multiple-site immunization followed by intravenous or intrasplenic boost injection was an appropriate immunizing method for the production of monoclonal anti-idiotope antibodies.

Differential effects of neuropeptide Y and opioids on neurogenic responses of the perfused rat mesentery

In perfused rat mesentery transmural nerve stimulation activates both adrenergic and capsaicin-sensitive sensory nerves. When adrenergic nerves were blocked with guanethidine and smooth muscle tone was increased, transmural nerve stimulation caused a dilator response which was attenuated by tetrodotoxin and abolished by capsaicin. Indomethacin increased the vasodilator response to transmural nerve stimulation, but did not affect the dilation to calcitonin gene-related peptide. Neuropeptide Y (NPY) potentiated vasoconstrictor responses to transmural nerve stimulation, but suppressed capsaicin-sensitive vasodilation, an effect which was unaltered by indomethacin. Opioid agonists selective for mu, delta or kappa receptors, DAMGO ([D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin), DPDPE ([D-Pen2,D-Pen5]enkephalin) and ethylketocyclazocine, had no effect on the vasoconstrictor response to transmural nerve stimulation. DAMGO and DPDPE significantly inhibited vasodilator responses to transmural nerve stimulation, but ethylketocyclazocine was without effect. After treatment with indomethacin, DAMGO still inhibited the vasodilator response, but DPDPE was no longer effective. Prejunctional control of transmitter release by NPY or opioids is dependent on the specific nerve type as well as, in some cases, the participation of endogenous prostaglandins.

Actions of dipyridamole on endogenous and exogenous noradrenaline in the dog mesenteric vein

1. In the isolated mesenteric vein of the dog, dipyridamole inhibited both the excitatory junction potential (e.j.p.) and the slow depolarization evoked by perivascular nerve stimulation, to 60-70% of control, with no change in the postjunctional membrane potential. These inhibitory actions of dipyridamole were not modified by 8-phenyltheophylline or phentolamine, suggesting that the inhibition did not involve either the actions of endogenous adenosine or the prejunctional alpha-autoregulation mechanism. 2. Dipyridamole did not produce any detectable effects on either the facilitation process of the e.j.ps or the postjunctional membrane depolarization produced by exogenously applied noradrenaline (NA). 3. Dipyridamole reduced the outflow of both the NA and the 3,4-dihydroxyphenylglycol (DOPEG) evoked by perivascular nerve stimulation to below 10% of control, the effect being much greater than that of exogenously applied adenosine (to about 90% of the control). 4. Exogenously-added NA was degraded by incubation with a segment of the vein. Dipyridamole itself produced degradation of NA and accelerated the NA-induced degradation. By contrast, pyrogallol, but not pargyline or imipramine, prevented the NA-induced degradation. 5. It is suggested that dipyridamole degrades NA directly, and also indirectly through activation of catechol-O-methyl transferase, with no alteration of the activity of monoamine oxidase or of the uptake mechanisms of NA into nerve terminals.

GABA agonists and omega conotoxin GVIA modulate responses to nerve activation of the perfused rat mesentery

The modulatory actions of gamma-aminobutyric acid (GABA) receptor agonists and omega-conotoxin GVIA (CTX) on sympathetic and sensory nerves were examined on contractile responses of the perfused rat mesentery to transmural nerve stimulation (TNS). GABA and baclofen, a selective GABAB receptor agonist, significantly inhibited vasoconstrictor responses to TNS, while muscimol, a selective GABAA receptor agonist, had no effect. In the guanethidine treated and methoxamine-contracted mesentery, TNS caused a vasodilator response which was unaffected by GABA. CTX (10(-8) M) markedly suppressed the vasoconstrictor response to TNS, but did not affect vasodilator responses. These findings suggest that in the rat mesentery: (1) GABA receptors modulate the activity of sympathetic nerves via prejunctional GABAB receptors, but do not influence sensory nerves, and (2) calcium channels which participate in sympathetic nerve activation have different properties than calcium channels in capsaicin-sensitive sensory nerves.

Comparative luminescence of rat liver Cu-thionein and its chemically synthesized alpha-domain

A peptide corresponding to the alpha-domain of rat liver metallothionein-2 was chemically synthesized employing the solid phase peptide synthesis technique. Its luminescence properties that depend on the coordinated Cu(I) have been studied using luminescence spectrometric titration in the presence of Cu(I). Unlike the intact metallothionein which has been converted into the Cu species, the emission and excitation spectra of the Cu-alpha-fragment showed a red shift by 20 nm and 65 nm, respectively, suggesting a more compact and stable luminophore in the alpha-domain. Saturation of Cu(I) coordination was reached in the presence of 6.5 mol eq Cu(I) when the alpha-fragment was used and 12 mol eq Cu(I) were specifically bound by the intact metallothionein. The emission bands were homogeneous and no decline of the cluster structure was observed when excessive Cu(I) was added after saturation. A rearrangement of the Cu-cluster in metallothionein during its formation seems to be plausible.

Reactivity of active center analogs of Cu2Zn2 superoxide dismutase on activated polymorphonuclear leukocytes

In unseparated human blood the Cu2Zn2 superoxide dismutase mimetic reactivity of several differently coordinated low Mr copper chelates on TPA-activated polymorphonuclear leukocytes was evaluated and compared to their apo-chelates, CuSO4, and the native enzyme. Similar to intact superoxide dismutase, 350-400 nM Cu flexibly complexed in a di-Schiff base mode in CuPu(Py)2 and CuPu(Im)2, respectively, was sufficient to inhibit the oxidative burst-dependent superoxide production of human blood phagocytes by 50%. Acetate- or biuret-type copper chelates behaved like CuSO4. The catalytic superoxide dismuting reactivity of the di-Schiff base active center analogs of SOD was confirmed using isolated porcine PMNs. Even in the presence of 600 microM albumin as a model for competitive copper chelation in biological fluids CuPu(Py)2 and CuPu(Im)2 remained active. The stability during the Cu(I)/Cu(II) redox cycling was demonstrated in the presence of activated PMNs and albumin, taking advantage of the electron paramagnetic properties of CuPu(Py)2 and CuPu(Im)2.

[Study of factors associated with preterm delivery]

A case-control study of preterm delivery was undertaken at the district of Qiaokou in Wuhan during October, 1987 to May, 1988. The study population consisted of 130 mothers of singleton preterm infants and 260 mothers of singleton term infants. The result of logistic regression analysis showed that significant factors of preterm delivery included low maternal stature, the young age of menarche, a previous induced abortion, a history of infertility problems, vaginal bleeding during the pregnancy, low weight gain during the pregnancy, premature rupture of membranes, hyperemesis gravidarum, and lack of antenatal care. The result also showed that psychosocial stress in pregnancy might be related to preterm delivery.

Efficacy of inactivated vaccine containing cyto-hemagglutinin against epidemic hemorrhagic fever in rabbits

Using the Z-10 strain of epidemic hemorrhagic fever virus (EHFV) as seed, and the primary cell of Meriones unguiculatus kidney tissue as incubation cell, a propiolactone inactivated epidemic hemorrhagic fever (EHF) vaccine was prepared, according to a similar procedure required for the production of biological products such as the Japanese B encephalitis vaccine. Besides the EHFV antigen detected by ELISA or reversed passive hemagglutination test (RPHA) as were used for the formalin inactivated vaccine, higher titres (1:128-1:1024) of EHFV hemagglutinin antigen was also detected in this EHFV vaccine. Immunization with twice intramuscular injection of this vaccine produced high titred (1:20-1:160) neutralizing antibody and low titred (1:10-1:20) hemagglutination antibody, in addition to the immunofluorescence (IF) and reversed passive hemagglutination inhibition (RPHI) antibodies. These results indicated an apparent difference in the immunogenicity between the beta-propiolactone and formalin inactivated EHF vaccines. With the approval of the Ministry of Health, human test is now underway in this laboratory.

Anti-idiotypic antibodies: preparation and identification; application to the detection of antigens of Plasmodium falciparum

Anti-idiotypic antibodies (anti 94D1Id and anti 94C3Id) were prepared by immunizing rabbits with designated monoclonal antibodies (MoAb) 94D1MoAb (94D1Id) and 94C3MoAb (94C3Id) specific for Plasmodium falciparum. The specificity of both was directed against idiotypes of the relevant MoAb. The interaction between 94D1Id and anti94D1Id or 94C3Id and anti94C3Id was almost completely inhibited when sufficient concentration of P. falciparum antigen was added, suggesting that the idiotypes recognized by anti94D1Id or anti94C3Id were located in the antigen binding site of the MoAbs or the construction of the V region of anti-idiotypic antibodies may be similar to that of P. falciparum antigenic determinants combining with MoAb. Each 4i assay (inhibition of idiotype-anti-idiotype interaction) had a different specificity and sensitivity in detecting P. falciparum asexual antigens. The 94C3Id-anti94C3Id system detected a minimal level of 0.001% parasitaemia and did not cross-react with other species, suggesting that 94C3Id-anti94C3Id system is species specific and may become a valuable tool for immunodiagnosis.

Inhibitory, opsonic and cytotoxic activities of monoclonal antibodies against asexual erythrocytic stages of Plasmodium falciparum

A range of monoclonal antibodies specific for Plasmodium falciparum were tested in vitro for their abilities to inhibit the multiplication of a partially synchronized culture of P. falciparum, to augment the phagocytosis of the parasites by macrophages, and to enhance the killing of parasites by peritoneal cells depleted of adherent cells. Seven of 17 monoclonal antibodies, ranging from culture supernatant fluid and ascitic fluid to purified IgG, showed dose- and time-dependent inhibition of parasite growth in vitro. At a concentration of 0.6 mg/ml, the inhibitory capacity of these monoclonal IgGs was above 94% over a 3-day culture period, much higher than that of the relevant polyclonal IgG. Four of 6 monoclonal antibodies tested augmented the phagocytosis of the parasites by macrophages, which occurred as a result of opsonization of the parasites. Four of 7 monoclonal antibodies examined showed cytotoxic activity on malaria parasites. Peritoneal cells depleted of adherent cells were capable of killing the parasites in the presence of monoclonal antibodies. These results indicate that there may be 'monofunction', 'bifunction', and 'multifunction' types of monoclonal antibodies against P. falciparum. The putative protective antigen of malaria parasites purified by 'multifunctional monoclonal antibody' affinity chromatography may have potential interest as a vaccine against the parasite or as an immunodiagnostic reagent for human malaria.

The production of reactive oxygen species in mice infected or immunized with Plasmodium berghei

The capacity of peritoneal exudate cells (PEC) obtained from mice infected or immunized with Plasmodium berghei to produce reactive oxygen species (ROS) and the biological basis of this response was investigated, using luminol-dependent zymosan-triggered chemiluminescence (CL). CL response of PEC from infected mice increased at the early stage but was significantly depressed at the later course of the infection. A similar biphasic activity of peroxidase was also observed in PEC from infected mice. On the other hand, PEC from immunized mice exhibited concomitant increases of the ability to produce CL, the activity of peroxidase and the expression of Fc and C3 receptors on cell surface. Compared with the controls, PEC from immunized mice showed an elevated background CL, responded more rapidly to the stimulation and generated considerably higher CL when triggered with opsonized zymosan. The data suggest that phagocytes in immunized mice are active in the production of ROS while those in infected mice are less active, and the inhibition of the ability of phagocytes to produce ROS may be one of the mechanisms for the parasites to escape from host immune system.