A comparison of 99Tcm-MIBI myocardial SPET and electron beam computed tomography in the assessment of coronary artery disease in two different age groups

The aim of this study was to compare the clinical value of 99Tcm-MIBI single photon emission tomography (SPET) and electron beam computed tomography (EBCT) in the assessment of coronary artery disease (CAD) in different age groups. 99Tcm-MIBI SPET (stress-rest), EBCT and coronary angiography studies were performed in 64 consecutive patients with suspected CAD. The patients were classified into two groups: Group A = 40 patients > 45 years of age and Group B = 24 patients < or = 45 years of age. There were 31 and 14 patients with coronary stenosis > or = 50% as determined by coronary angiography in Groups A and B, respectively. All patients (30 cases) with abnormal 99Tcm-MIBI myocardial SPET and coronary calcification detected by EBCT had significant coronary artery disease, and 93.3% of the patients with normal 99Tcm-MIBI SPET and normal EBCT had normal coronary angiography or < 50% lumen narrowing of the coronary arteries. In Group B, the sensitivity of SPET for detecting CAD was significantly higher than that of EBCT (92.9 vs 42.9%, P < 0.01); the specificity of SPET was comparable to that of EBCT. In Group A, there was no significant difference between SPET and EBCT in terms of sensitivity (93.6 vs 90.3%) or specificity (88.9 vs 55.6%). However, in the detection of individual coronary artery disease, the specificity of SPET was significantly higher than that of EBCT in Group A (94.1 vs 66.7%, P < 0.001). The sensitivity of SPET was again significantly higher than that of EBCT (85.7 vs 38.1%, P < 0.005) in Group B. The accuracy of SPET was higher than that of EBCT in both groups (82.5 vs 67.5%, P < 0.01 in Group A; 93.1 vs 76.4%, P < 0.01 in Group B, respectively). We conclude that 99Tcm-MIBI myocardial perfusion SPET has a higher sensitivity than EBCT in the detection of CAD in patients < or = 45 years old and a higher specificity in patients > 45 years of age. A combination of SPET and EBCT may assess CAD more accurately.

Acute paw oedema induced by local injection of adenosine A(1), A(2) and A(3) receptor agonists

The present study used plethysmometry to examine oedema following local injection of selective adenosine A(1), A(2) and A(3) receptor agonists and inhibitors of adenosine metabolism into the hindpaw of the rat. N(6)-Cyclopentyladenosine and L-N(6)-phenylisopropyladenosine (A(1)), 2-[p(2-carboxyethyl) phenethylamino]-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS21680) (A(2A)) and N(6)-benzyl-5'-N-ethylcarboxamido adenosine (N(6)-B-NECA) (A(3)) all produced an increase in paw volume (N(6)N(6)-cyclopentyladenosine, L-N(6)CGS21680). At the highest dose, each agent also produced a systemically mediated suppression of oedema. Oedema by N(6)-cyclopentyladenosine was blocked by caffeine, 8-cyclopentyl-1,3-dimethylxanthine and enprofylline. Oedema by CGS21680 was blocked by caffeine and 8-cyclopentyl-1, 3-dimethylxanthine. Oedema by N(6)-B-NECA was blocked by enprofylline, but not by caffeine or 8-cyclopentyl-1, 3-dimethylxanthine, or by systemic administration of MRS 1191. Oedema by both N(6)-cyclopentyladenosine and N(6)-B-NECA was blocked by mepyramine, ketanserin and phentolamine, but that by CGS21680 was not. The adenosine kinase inhibitor 5'-amino-5'-deoxyadenosine and the adenosine deaminase inhibitor 2'-deoxycoformycin produced only a limited increase in paw volume, and this was blocked by caffeine. This study demonstrates an acute paw oedema response following local administration of adenosine A(1), A(2) and A(3) receptor agonists, which likely results from different mechanisms of action in each case.

Effects of ligustrazine, tanshinone II A, ubiquinone, and idebenone on mouse water maze performance

AIM

To observe the effects of four drugs, ligustrazine (Lig), tanshinone II A (Tan), ubiquinone (Ubi) and idebenone (Ide), on learning and memory of mouse.

METHODS

Mouse water maze was used to evaluate nootropic effect.

RESULTS

In comparison with the defective model (only scopolamine 3 mg.kg-1, Tan 20 mg.kg-1, ig) shortened the escape latency dramatically from (36 +/- 19) s to (11 +/- 5) s (P < 0.01) and reduced errors from 7 +/- 5 to 1.5 +/- 1.3 (P < 0.05). Ubi 20 mg.kg-1 ig decreased the escape latency from (37 +/- 18) s to (17 +/- 12) s and errors from 8 +/- 5 to 2.1 +/- 2.7 (P < 0.01). Ide 120 mg.kg-1 (ig) reduced the errors from 8 +/- 6 to 3.4 +/- 2.9 (P < 0.05), but had no remarkable effect on the escape latency. Lig did not exhibit marked effect on the deficit.

CONCLUSION

Tan, Ubi, and Ide improved scopolamine-caused spatial performance defects in mouse.

Nephroblastoma overexpressed gene (NOV) codes for a growth factor that induces protein tyrosine phosphorylation

NOV (nephroblastoma overexpressed gene) is a member of the CCN (connective tissue growth factor [CTGF], Cyr61/Cef10, NOV) family of proteins. These proteins are cysteine-rich and are noted for having growth-regulatory functions. We have isolated the rat NOV gene, and the DNA sequence shares 90% identity with the mouse and 80% identity with the human sequences. The rat NOV gene was expressed in all rat tissues examined, including brain, lung, heart, kidney, liver, spleen, thymus and skeletal muscle. Higher levels of rat NOV mRNA were seen in the brain, lung and skeletal muscle compared to the other tissues. Examination of NOV expression in various human cell lines revealed that NOV was expressed in U87, 293, T98G, SK-N-MC and Hs683 but not in HepG2, HL60, THP1 and Jurkat. The human NOV gene was transfected into 293 cells and the expressed protein purified. When 3T3 fibroblasts were treated with this recombinant NOV protein, a dose-dependent increase in proliferation was observed. Analysis of tyrosine-phosphorylated proteins revealed that when 3T3 cells were treated with NOV, a 221 kDa protein was phosphorylated. These data suggest that NOV can act as a growth factor for some cells and binds to a specific receptor that leads to the phosphorylation of a 221 kDa protein.

[Cadmium concentrations in hair, urine and blood among residents in a cadmium-polluted area, Nagasaki, Japan: a 18-year follow-up after soil replacement]

In 1981, the soil of cadmium (Cd)-polluted rice fields was replaced with new soil in Kashine, a Cd-polluted district located on Tsushima Island, Nagasaki Prefecture, Japan. Consequently, the average dietary Cd intake among the inhabitants decreased from 215 micrograms/day in 1969 to 106 micrograms/day in 1983. The authors investigated the health status of Kashine inhabitants before and after the reduction of Cd intake. Concentrations of beta 2-microglobulin in urine (U-beta 2-mg) and Cd in urine (U-Cd), hair (H-Cd) and blood (B-Cd) were measured on 35 inhabitants in 1979 and 1996. The geometric mean of U-beta 2-mg concentration for 9 subjects with U-beta 2-mg levels > or = 1,000 micrograms/g creatinine (microgram/g cr) in 1979 increased by approximately 2.5-fold in 1996. Meanwhile there was little change in the geometric mean for 26 subjects with U-beta 2-mg levels < 1,000 micrograms/g cr in 1996. It was concluded that renal tubular dysfunction among Cd-exposed inhabitants was irreversible and progressive, even after dietary Cd intake decreased. The geometric mean of U-Cd concentration decreased significantly from 11.0 micrograms/g cr in 1979 to 6.3 micrograms/g cr in 1996. The decrease in U-Cd concentrations was significantly greater among inhabitants with U-beta 2-mg levels > or = 1,000 micrograms/g cr than among those with U-beta 2-mg levels < 1,000 micrograms/g cr (p = 0.03). From these results, it was considered that the level of U-Cd was more decreased by the presence of renal tubular dysfunction. The geometric mean of H-Cd concentration decreased significantly from 109.1 micrograms/kg in 1979 to 55.1 micrograms/kg in 1996. However, it was unclear whether the decrease of H-Cd depended on the decrease of dietary Cd intake, decrease of body burden or both, because U-Cd concentrations also decreased by approximately 43% during this period. H-Cd concentration was weakly and positively correlated with U-Cd (r = 0.38-0.44), an indicator of body burden of Cd. These results suggested that H-Cd concentration was influenced by the body burden of this metal. The geometric mean of B-Cd concentration in 33 inhabitants was 5.7 micrograms/l in 1996. The geometric mean was significantly greater in subjects with initial U-beta 2-mg levels > or = 1,000 micrograms/g cr than in those with U-beta 2-mg levels < 1,000 micrograms/g cr. A close positive correlation was found between B-Cd concentrations and U-Cd (r = 0.70, p < 0.01). It was suggested that the body burden influenced the levels of B-Cd as well as U-Cd, many years after Cd exposure had decreased.

Differential distribution of urocortin- and corticotropin-releasing factor-like immunoreactivities in the rat brain

Urocortin, a novel 40 amino acid neuropeptide, is a member of the corticotropin-releasing factor family. With 45% homology to corticotropin-releasing factor, urocortin binds with similar affinity to the corticotropin-releasing factor- and corticotropin-releasing factor-2 receptors and may play a role in modulating many of the same systems as corticotropin-releasing factor. To assess whether urocortin and corticotropin-releasing factor are localized in the same regions of the brain, we compared the distribution of urocortin- and corticotropin-releasing factor-like immunoreactivities in the rat central nervous system. Polyclonal antibodies to rat corticotropin-releasing factor and rat urocortin were generated and utilized to map the distribution of corticotropin-releasing factor- and urocortin-like immunoreactivities throughout the rat forebrain and brainstem. Characterization of the antibodies by radioimmunoassay showed no cross-reactivity with related peptides. Male Sprague-Dawley rats were treated with colchicine for 18-24 h. Following colchicine treatment, the rats were perfused with paraformaldehyde-lysine-periodate fixative and their brains removed. Serial coronal sections were taken throughout the rat brain and processed for either corticotropin-releasing factor- or urocortin-like immunoreactivity. Urocortin-like immunoreactivity shows a discrete localization within several regions including the supraoptic nucleus, the median eminence, Edinger-Westphal nucleus and the sphenoid nucleus. This is in contrast to the more abundant corticotropin-releasing factor-like immunoreactivity. Regions containing high levels of corticotropin-releasing factor immunoreactivity include the lateral septum, paraventricular nucleus of the hypothalamus, median eminence and locus coeruleus. There are a few regions that contain both urocortin-immunoreactive and corticotropin-releasing factor-immunoreactive cells, such as the supraoptic nucleus and the hippocampus. Therefore, urocortin and corticotropin-releasing factor appear to have different distribution patterns which may be indicative of their respective physiological functions.

RHO-associated protein kinase alpha potentiates insulin-induced MAP kinase activation in Xenopus oocytes

We recently identified Xenopus Rho-associated protein kinase alpha (xROKalpha) as a Xenopus insulin receptor substrate-1 binding protein and demonstrated that the non-catalytic carboxyl terminus of xROKalpha binds Xenopus insulin receptor substrate-1 and blocks insulin-induced MAP kinase activation and germinal vesicle breakdown in Xenopus oocytes. In the current study we further examined the role of xROKalpha in insulin signal transduction in Xenopus oocytes. We demonstrate that injection of mRNA encoding the xROKalpha kinase domain or full length xROKalpha enhanced insulin-induced MAP kinase activation and germinal vesicle breakdown. In contrast, injection of a kinase-dead mutant of xROKalpha or pre-incubation of oocytes with an xROKalpha inhibitor significantly reduced insulin-induced MAP kinase activation. To further dissect the mechanism by which xROKalpha may participate in insulin signalling, we explored a potential function of xROKalpha in regulating cellular Ras function, since insulin-induced MAP kinase activation and germinal vesicle breakdown is known to be a Ras-dependent process. We demonstrate that whereas injection of mRNA encoding c-H-Ras alone induced xMAP kinase activation and GVBD in a very low percentage (about 10%) of injected oocytes, co-injection of mRNA encoding xROKalpha and c-H-Ras induced xMAP kinase activation and germinal vesicle breakdown in a significantly higher percentage (50-60%) of injected oocytes. These results suggest a novel function for xROKalpha in insulin signal transduction upstream of cellular Ras function.

Postnatal profiles of glycogenolysis and gluconeogenesis are modified in rat pups by maternal dietary glucose restriction

Because glucose is an important metabolic fuel during perinatal development, the effect of restriction of maternal dietary glucose on the developmental profile of neonatal glucoregulatory pathways was investigated. Pregnant rats were fed isoenergetic diets (0, 12, 24 or 60% glucose) and offspring were killed at seven postpartum time periods: 0-2, 4-6, 12-16 and 24 h, and 3, 6 and 15 d. Failure of the most restricted pups (0%) to survive 24 h was explained by persistent hypoglycemia resulting from the following: 1) insufficient tissue glycogen reserves at birth; 2) lower liver glycogen mobilization; 3) delayed phosphorylase a induction; and 4) low phosphoenolpyruvate carboxykinase (PEPCK) gene expression, all of which occurred despite the lower insulin:glucagon ratio. Differences in liver glycogen stores, which had been exhausted in all dietary groups by 16 h, could not account for the high d 1 pup mortality in the moderately restricted (12 and 24% glucose) groups. However, a certain metabolic distress was suggested because these moderately restricted neonates had significantly higher liver PEPCK gene expression at 12-16 h but significantly lower plasma glucose at 24 h. The high d 3 mortality, confirmed by analysis of deviance, was not supported by significant differences in any of the measured glucoregulatory indices. We conclude that dietary glucose during pregnancy is required for neonatal survival; its restriction not only lowers tissue glycogen reserves, but can disrupt the normal gene expression of liver PEPCK and the neonatal profile of phosphorylase a activity. Importantly, these observations show that the development of neonatal glucoregulatory mechanisms is modified by the availability of maternal dietary glucose.

Growth induction of hepatic stimulator substance in hepatocytes through its regulation on EGF receptors

The cytosolic liver-specific growth factor-hepatic stimulator substance (HSS) has been shown to be able to amplify the rat hepatocyte proliferation responded to EGF. In order to get more insight into the mechanism, the regulatory effect of HSS on EGF-receptor (EGF-R) and the receptor phosphorylation at molecular level was studied. HSS partially purified from weanling rat liver was given to cultured hepatocytes and its influence on EGF-R specific binding and internalization as well as mRNA expression were investigated. The results showed that preincubation of hepatocytes with HSS could lead to an increase in [125I]-EGF binding to its receptors and inhibit EGF-induced receptor down-regulation. Furthermore, the over-expression of EGF-R mRNA stimulated by HSS was seen during 2-12 h after the incubation. Additionally, it was demonstrated with human hepatoma SMMC-7721 cells in Western blot that the EGF-R expression and the receptor autophosphorylation were increased with dose/time-dependency after HSS treatment. These results strongly suggest that the mechanism of HSS action on hepatocyte growth might be related to its modulation on EGF-R and receptor-mediated signaling transduction.

Posterior gut development in Drosophila: a model system for identifying genes controlling epithelial morphogenesis

The posterior gut of the Drosophila embryo, consisting of hindgut and Malpighian tubules, provides a simple, well-defined system where it is possible to use a genetic approach to define components essential for epithelial morphogenesis. We review here the advantages of Drosophila as a model genetic organism, the morphogenesis of the epithelial structures of the posterior gut, and what is known about the genetic requirements to form these structures. In overview, primordia are patterned by expression of hierarchies of transcription factors; this leads to localized expression of cell signaling molecules, and finally, to the least understood step: modulation of cell adhesion and cell shape. We describe approaches to identify additional genes that are required for morphogenesis of these simple epithelia, particularly those that might play a structural role by affecting cell adhesion and cell shape.

[Regulatory effect of hepatic stimulator substance on the proliferation of human hepatoma cells]

The hepatic stimulator substance (HSS) was prepared from weanling rat livers by ultracentrifugation and Sephadex G-75 chromatography. The stimulatory effects of HSS on cell proliferation, EGF receptor expression and receptor tyrosine phosphorylation were investigated in serum-free cultured human hepatoma cell line SMMC-7721. The results showed: (1) The relative percentage of S-phase cells was increased in HSS-treated cells. (2) EGF receptor protein level was increased after the cells were treated with HSS for 12-24 h and this effect was dose- and time-dependent. (3) Treatment of the cells with HSS for 0.5-15 min resulted in the autophosphorylation of EGF receptor tyrosine residue dramatically. The above results suggest that the proliferative action of HSS on hepatocytes might be due to its modulation of EGF receptor expression and the signaling pathway.

Characterization of [125I-Tyr0]-corticotropin releasing factor (CRF) binding to the CRF binding protein using a scintillation proximity assay

We describe the characterization of high affinity [125I-Tyr0]-human CRF binding to purified recombinant human CRF-binding protein (CRF-BP) using a scintillation proximity assay (SPA). For this stable nonseparation technique developed in 96 well microtiter plates, biotinylated CRF-BP is captured by streptavidin-coated SPA beads for the detection of bound [125I-Tyr0]-CRF. Unbound [125I-Tyr0]-CRF represented little or no signal in the assay. Total binding observed was greater than 5000 cpm with a nonspecific signal of < 100 cpm determined in the presence of excess unlabeled human CRF. A comparison of the SPA method with a charcoal precipitation method confirmed that the biotinylation procedure did not adversely affect affinity of the CRF-BP for [125I-Tyr0]-CRF. Saturation binding analysis yielded an apparent equilibrium dissociation constant (Kd) of 208 +/- 5.0 pM (+/- S.D., n = 3). An inhibition constant (Ki) for unlabeled CRF was calculated to be 0.22 +/- 0.03 nM (+/- S.D., n = 8) and a pharmacological profile for eight CRF-related neuropeptides gave a rank potency similar to previously reported results. Finally, the assay variability was assessed with intra- and inter-plate coefficients of variation which were less than 5% each.

A novel insulin receptor substrate protein, xIRS-u, potentiates insulin signaling: functional importance of its pleckstrin homology domain

A novel Xenopus insulin receptor substrate cDNA was isolated by hybridization screening using the rat insulin receptor substrate-1 (IRS-1) cDNA as a probe. The xIRS-u cDNA encodes an open reading frame of 1003 amino acids including a putative amino-terminal pleckstrin homology (PH) domain and phosphotyrosine-binding (PTB) domain. The carboxy terminus of xIRS-u contains several potential Src homology 2 (SH2)-binding sites, five of which are in the context of YM/LXM (presumptive binding sites for phosphatidylinositol 3-kinase). It also contains a putative binding site for Grb2 (YINID). Pair-wise amino acid sequence comparisons with the previously identified xIRS-1 and the four members of the mammalian IRS family (1 through 4) indicated that xIRS-u has similar overall sequence homology (33-45% identity) to all mammalian IRS proteins. In contrast, the previously isolated xIRS-1 is particularly similar (67% identical) to IRS-1 and considerably less similar (31-46%) to the other IRS family members (2 through 4). xIRS-u is also distinct from xIRS-1, having an overall sequence identity of 47%. These sequence analyses suggest that xIRS-u is a novel member of the IRS family rather than a Xenopus homolog of an existing member. Microinjection of mRNA encoding a Myc-tagged xIRS-u into Xenopus oocytes resulted in the expression of a 120-kDa protein (including 5 copies of the 13-amino acid Myc tag). The injection of xIRS-u mRNA accelerated insulin-induced MAP kinase activation with a concomitant acceleration of insulin-induced oocyte maturation. An aminoterminal deletion of the PH domain (xIRS-u deltaPH) significantly reduced the ability of xIRS-u to potentiate insulin signaling. In contrast to the full-length protein, injection of xIRS-u (1-299), which encoded the PH and PTB domain, or xIRS-u (1-170), which encoded only the PH domain, blocked insulin signaling in Xenopus oocytes. Finally, xIRS-u (119-299), which had a truncated PH domain and an intact PTB domain, had no effect on insulin signaling. This is the first report that the PH domain of an IRS protein can function in a dominant negative manner to inhibit insulin signaling.

Effect of intravenous infusions of 12-O-tetradecanoylphorbol-13-acetate (TPA) in patients with myelocytic leukemia: preliminary studies on therapeutic efficacy and toxicity

Studies by several investigators have shown that 12-0-tetradecanoylphorbol-13-acetate (TPA) is an extraordinarily potent stimulator of differentiation of cultured human promyelocytic leukemia cells in vitro. In the present study, TPA was administered to humans by i.v. infusion without irreversible toxicity, and it was shown to have pharmacological activity for the treatment of myelocytic leukemia in patients refractory to cytosine arabinoside (Ara C), retinoic acid, and other antileukemic drugs. Marked decreases in bone marrow myeloblasts as well as temporary remission of disease symptoms were observed when TPA was administered alone or in combination with vitamin D3 and Ara C. Additional studies with TPA after the determination of optimum dosing regimens are needed to determine whether long-lasting or permanent remissions of myelocytic leukemia can be achieved. Transient and reversible side effects were observed after a 1-mg i.v. dose of TPA, but these adverse effects became less intense or disappeared when a lower dose of TPA was used. The results of this study indicate a therapeutic effect of TPA in patients with myelocytic leukemia.

Molecular cloning and characterization of Xenopus insulin-like growth factor-1 receptor: its role in mediating insulin-induced Xenopus oocyte maturation and expression during embryogenesis

We have cloned a complementary DNA encoding the putative Xenopus insulin-like growth factor-1 (xIGF-1) receptor. Injection of messenger RNA derived from the cloned complementary DNA into Xenopus oocytes resulted in the expression and correct processing of the receptor's alpha- and beta-subunits. Using antibodies generated against protein expressed against the cloned sequence, we demonstrated that the endogenous xIGF-1 receptor in Xenopus oocytes was activated by nanomolar concentrations of mammalian IGF-1 and by insulin approximately 100-fold higher in concentration. This receptor activation profile correlated with hormone-induced Xenopus oocyte maturation. Furthermore, injection of a neutralizing antiinsulin receptor antibody into Xenopus oocytes inhibited hormone-induced xIGF-1 receptor activation. These results provide molecular and biochemical evidence supporting a role for xIGF-1 receptor in mediating insulin/IGF-1-induced Xenopus oocyte maturation. We also report here that embryonic transcription of xIGF-1 receptor is activated during the formation of the central nervous system in early Xenopus embryos.

A rho-associated protein kinase, ROKalpha, binds insulin receptor substrate-1 and modulates insulin signaling

Insulin receptor substrate-1 (IRS-1) is phosphorylated on multiple tyrosine residues by ligand-activated insulin receptors. These tyrosine phosphorylation sites serve to dock several Src homology 2-containing signaling proteins. In addition, IRS-1 contains a pleckstrin homology domain and a phosphotyrosine binding domain (PTB) implicated in protein-protein and protein-lipid interactions. In a yeast two-hybrid screening using Xenopus IRS-1 (xIRS-1) pleckstrin homology-PTB domains as bait, we identified a Xenopus homolog of Rho-associated kinase alpha (xROKalpha) as a potential xIRS-1-binding protein. The original clone contained the carboxyl terminus of xROKalpha (xROK-C) including the putative Rho binding domain but lacking the amino-terminal kinase domain. Further analyses in yeast indicated that xROK-C bound to the putative PTB domain of xIRS-1. Binding of xROK-C to xIRS-1 was confirmed in Xenopus oocytes after microinjection of mRNA corresponding to xROK-C. Furthermore, microinjection of xROK-C mRNA inhibited insulin-induced mitogen-activated protein kinase activation with a concomitant inhibition of oocyte maturation. In contrast, microinjection of xROK-C mRNA did not inhibit mitogen-activated protein kinase activation or oocyte maturation induced by progesterone or by microinjection of viral Ras (v-Ras) mRNA. These results suggest that xROKalpha may play a role in insulin signaling via a direct interaction with xIRS-1.

Displacement of insulin-like growth factors from their binding proteins as a potential treatment for stroke

Insulin-like growth factors I and II (IGF-I and IGF-II) play an important role in normal growth and brain development and protect brain cells from several forms of injury. The effects of IGFs are mediated by type-I and type-II receptors and modulated by potentially six specific binding proteins that form high-affinity complexes with IGFs in blood and cerebrospinal fluid (CSF) and under most circumstances inactivate them. Because brain injury is commonly associated with increases in IGFs and their associated binding proteins, we hypothesized that displacement of this large "pool" of endogenous IGF from the binding proteins would elevate "free" IGF levels to elicit neuroprotective effects comparable to those produced by administration of exogenous IGF. A human IGF-I analog [(Leu24, 59, 60, Ala31)hIGF-I] with high affinity to IGF-binding proteins (Ki = 0.3-3.9 nM) and no biological activity at the IGF receptors (Ki = >10,000 nM) increased the levels of "free, bioavailable" IGF-I in the CSF. Intracerebroventricular administration of this analog up to 1h after an ischemic insult to the rat brain had a potent neuroprotective action comparable to IGF-I. This novel strategy for increasing "free" IGF levels in the brain may be useful for the treatment of stroke and other neurodegenerative diseases.

A comparison of 99mTc-MIBI myocardial SPET with electron beam computed tomography in the assessment of coronary artery disease

We compared technetium-99m methoxyisobutylisonitrile (MIBI) myocardial perfusion single-photon emission tomography (SPET) (MPS) and electron beam computed tomography (EBCT) in order to assess their respective value in the detection of coronary artery disease (CAD). 99mTc-MIBI SPET (stress-resting) and EBCT studies were performed in 51 patients with suspected CAD who underwent coronary angiography (CAG). CAG showed that of the 51 patients, 36 had coronary stenosis >/=50% while 15 had normal results. A moderate positive rank correlation was found between coronary calcification detected by EBCT and MPS score (rs=0.5283, P<0.01). The concordance between EBCT and MPS for the evaluation of CAD was 72.5% (37/51). The sensitivity of EBCT in detecting CAD in 51 patients was comparable to that of MPS (81% vs 94%, NS). However, the accuracy of EBCT was lower than that of MPS (78% vs 94%, P<0.025). As regards the detection of individual coronary artery disease, there was no significant difference in sensitivity between EBCT and MPS (65% vs 75%, NS); however, the specificity and accuracy of EBCT were lower than those of MPS (specificity: 77% vs 95%, P<0.005; accuracy 71% vs 85%, P<0.005). The sensitivity, specificity and accuracy of MPS in detecting single-vessel disease were higher than those of EBCT (sensitivity: 86% vs 42%, P<0.025; specificity: 96% vs 70%, P<0.025; accuracy: 93% vs 61%, P<0.005). However, no significant differences in the sensitivity, specificity and accuracy of MPS and EBCT were found in respect of multivessel disease.

IN CONCLUSION

99mTc-MIBI myocardial perfusion SPET and EBCT provide different information in the assessment of CAD. The sensitivity of EBCT for the detection of CAD is comparable with that of MPS; however, the specificity and accuracy of EBCT are lower than those of MPS. More reliable results will be obtained if both myocardial perfusion SPET and EBCT are performed.

Expression and characterization of a putative high affinity human soluble leptin receptor

Leptin, a circulating 16-kDa protein secreted by adipocytes, decreases body weight by reducing food intake and enhancing energy utilization. Leptin receptors that share homology to the glycoprotein gp130 have been recently cloned. In addition, differentially spliced leptin receptor messenger RNAs have been identified. Functional mutations in either the leptin or leptin receptor gene cause obesity. In the present study, expression of the full length human leptin receptor complementary DNA encoding the long cytoplasmic domain of leptin receptor in COS7 cells resulted in high affinity membrane binding of 125I-leptin (Ki approximately 200 pM); no detectable binding was present in the medium. In addition, we expressed the extracellular domain of human leptin receptor in COS7 cells and identified a soluble leptin receptor in the conditioned medium that binds human and mouse leptin with high affinity comparable with the full length membrane receptor. Transfected COS7 cells expressing the soluble leptin receptor also demonstrated modest specific 125I-leptin binding in whole cells, presumably due to association of the soluble leptin receptor to cell membrane proteins. Data from cross-linking studies identified two specific bands in the 125I-leptin/soluble leptin receptor complex with molecular masses of approximately 130-150 kDa and 300 kDa. The 130-150 kDa molecular mass was confirmed in Western blot analysis and Coomassie staining of the purified soluble receptor and probably represents the glycosylated form of the receptor. The 300-kDa band most likely represents a homodimer of the soluble leptin receptor complex because HPLC gel filtration analysis of the 125I-leptin/soluble leptin receptor complex identified a single peak corresponding to a molecular mass of approximately 340 kDa. The soluble leptin receptor antagonized 125I-leptin binding to the membrane receptor, suggesting its potential utility as a functional tool for determining the role of endogenous leptin.

[An experimental study on inhibitory effect of Chinese medicine tai-bao on antisperm antibody]

OBJECTIVE

To investigate whether Chinese medicine Tai-bao could inhibit antisperm antibody in experimental mice.

METHODS

The experimental immunoinfertility mice were due to antisperm antibody induced by injection of human sperm membrane antigens. The experimental immuno-infertile mice used in the present study were divided into four groups including Tai-bao high dose group (46.8 g.kg-1.d-1), Tai-bao low dose group (31.2 g.kg-1.d-1), prednisone group and normal saline group. The enzyme linked immune sorbent assay (ELISA) and microcytotoxic assay were used for detection of antisperm antibody. The change of levels of antisperm antibody before and after treatment, pregnant rate, and the number of implantation were investigated in tested mice.

RESULTS

The pregnant rates in normal saline group, prednisone group, Tai-bao high dose group and low dose were 38.89%, 47.06%, 70.00% and 75.00% respectively. The rate of pregnancy in Tai-bao low dose group was significantly higher as compared with normal saline group (P < 0.05). The rate of implantation in Tai-bao low dose group was significantly higher than that in prednisone group (P < 0.05). The results of detection of the cytotoxic antibody to sperm showed that cytotoxic percentages in Tai-bao high dose group (63.0 +/- 10.3%) and prednisone group (56.3 +/- 13.7%) were significantly lower (P < 0.05 and P < 0.01) than that in normal saline group (72.84 +/- 5.05%).

CONCLUSION

Chinese medicine Tai-bao possesses regulatory effect on reproductive immune function, inhibitory effect on antisperm cytotoxic antibody, and promoting effect on pregnancy.

Immunosuppressive phenotype of corticotropin-releasing factor transgenic mice is reversed by adrenalectomy

Stress elicits a wide range of physiological changes involving the nervous, endocrine, and immune systems. Corticotropin-releasing factor (CRF) plays a key role in orchestrating this response, activating both the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, resulting in release of corticosteroids. The present study examines the immunological phenotype and responsiveness of CRF-transgenic (CRF-Tg) mice. The immune system of the CRF-Tg animals has profound changes compared to littermate controls, including a marked reduction in both cell number and immune responsiveness. There were also phenotypic changes in the lymphocytic composition of the various lymphoid organs, most notably in the spleen, where CRF-Tg mice had a greater percentage of T lymphocytes compared to littermate controls. Adrenalectomy of CRF-Tg reversed the immunological phenotype observed and restored immune responsiveness. These results demonstrate that CRF overexpression leads to profound impairment on lymphocyte development and function mediated via corticosteroids.

Maternal dietary glucose modifies phosphoenolpyruvate carboxykinase (PEPCK) gene expression in the kidney of newborn rats

The consequence of low maternal dietary glucose on perinatal phosphoenolpyruvate carboxykinase (PEPCK EC 4.1.32) gene expression was investigated. Pregnant rats were fed isoenergetic diets containing graded levels of glucose (0, 12, 24, and 60%) from gestation day 2 to lactation day 15. The postnatal developmental profile of PEPCK mRNA in the neonatal kidney was analysed by Northern blot and presented as PEPCK/GAPDH mRNA ratios. In comparison with the 24 and 60% dietary groups, maternal dietary glucose restriction (0 or 12%) during pregnancy resulted in a significant delay in postnatal renal PEPCK gene expression. In these glucose restricted pups, renal PEPCK mRNA was barely detected at birth and was fully visualized only at 4-6 hr; it peaked 24 hr after birth, which was 12 hr later than pups born to dams fed 24 or 60% glucose diets. These results demonstrate for the first time that maternal dietary glucose can modify postnatal renal PEPCK gene expression during perinatal development when glucose homeostasis via gluconeogenesis is critical for neonatal survival.

Blockade of nitric oxide-induced relaxation of rabbit aorta by cysteine and homocysteine

AIM

To examine the inhibition by L-cysteine (Cys) and L-homocysteine (HoCys) of NO-induced relaxation of aorta.

METHODS

The tension of rabbit aortic rings in oxygenated Krebs' solution was recorded isometrically.

RESULTS

Pretreatment of endothelium-denuded rings with Cys or HoCys inhibited the NO-induced increase in cGMP. The inhibitory effects of Cys or HoCys on relaxation responses to subsequent additions of NO 75 nmol.L-1 gradually diminished with time, which was consistent with the loss of the sulfhydryl concentration of Cys and HoCys. Superoxide dismutase (SOD) 35 kU.L-1 attenuated the inhibition by Cys and HoCys of NO-induced relaxation. Neither boiled SOD nor catalase 100 kU.L-1 antagonized the inhibitory effects of Cys. Preaddition of SOD 35 kU.L-1 inhibited the reduction of cytochrome C by Cys. Increasing concentrations of SOD from 35 to 350 kU.L-1 intensified the cytochrome C reduction. Addition of xanthine 300 mumol.L-1 plus xanthine oxidase 1 U.L-1 to the mixture of cytochrome C 60 mumol.L-1 and Cys 100 mumol.L-1 produced an additional augmentation of SOD-inhibitable reduction of cytochrome C. The rate of the reduction of cytochrome C induced by HoCys 100 mumol.L-1 was much slower than with Cys. Addition of NO reduced the SH concentrations of both the supernatant of aortic homogenate and Cys in Krebs' solution.

CONCLUSION

The inhibition by the SH compounds of NO is mediated partly by the superoxide generated by the auto-oxidation of these compounds, and partly by a direct reaction of SH groups with NO.

Quantitative analysis of technetium 99m 2-methoxyisobutyl isonitrile single-photon emission computed tomography and isosorbide dinitrate infusion in assessment of myocardial viability before and after revascularization

BACKGROUND

Assessment of viable myocardium in territories of hypoperfused myocardium is important for predicting functional recovery after revascularization. This study was designed to evaluate quantitative analysis of 99mTc-labeled 2-methoxyisobutyl isonitrile (MIBI) myocardial perfusion imaging combined with isosorbide dinitrate (ISDN) infusion to detect myocardial viability in patients with chronic coronary artery disease before and after revascularization.

METHODS AND RESULTS

Twenty-seven consecutive patients with previous myocardial infarction and left ventricular dysfunction (left ventricular ejection fraction 35.2% +/- 13.5%) referred for coronary artery bypass (CABG) were studied with 99mTc-labeled MIBI single-photon emission computed tomography at rest and during ISDN infusion before CABG followed by resting imaging after CABG. Quantitative analysis was performed with circumferential profiles. Left ventricular function (global and regional) was assessed by radionuclide ventriculography before and after CABG. Out of 212 abnormal perfusion segments with resting 99mTc-labeled MIBI SPECT, 99 segments (47%) showed improved uptake of 99mTc-labeled MIBI during ISDN infusion. The mean ratio of myocardial uptake was 0.58 +/- 0.25 (resting 0.53 +/- 0.23; p < 0.05). After CABG, of 212 segments with hypoperfusion, 108 segments (51%; p > 0.05 vs ISDN) showed improved uptake of 99mTc-labeled MIBI. The mean ratio of myocardial uptake was 0.60 +/- 0.26 (resting 0.53 +/- 0.23; p < 0.05). The concordance between the improvement of post-CABG wall motion and that of pre-CABG ISDN perfusion imaging was 83%, between the improvement of wall motion and perfusion imaging after CABG 94%, and between the improvement of pre-CABG ISDN and post-CABG perfusion imaging 83%, respectively.

CONCLUSION

ISDN infusion can improve the uptake of 99mTc-labeled MIBI in hypoperfused myocardium and increase the efficiency of 99mTc-labeled MIBI in the detection of viable myocardium in patients with previous myocardial infarction and left ventricular dysfunction.

Cloning of a cDNA encoding a novel interleukin-1 receptor related protein (IL 1R-rp2)

We have identified and isolated both the rat and human cDNAs for a novel putative receptor related to the interleukin-1 type 1 receptor. We have named this protein interleukin 1 receptor related protein two (IL 1R-rp2). The rat cDNA for IL1R-rp2 was first identified using oligonucleotides of degenerate sequence in a polymerase chain reaction (PCR) paradigm with rat brain mRNA as the template. The protein encoded by both of these cDNAs are 561 amino acids long and exhibit 42% and 26% overall identity with the interleukin-1 type 1 and type 2 receptors, respectively. RNase protection assays from rat tissues revealed a predominant expression for IL 1R-rp2 in the lung and epididymis with lower levels detected in the testis and cerebral cortex. By in situ hybridization we were able to determine that the expression in rat brain appeared to be non-neuronal and associated with the cerebral vasculature. When expressed transiently in COS-7 cells the receptor was incapable of high affinity binding to either [125I]-recombinant human IL 1 alpha or [125I]-recombinant human IL 1 beta. Together, these data demonstrate the existence of a novel protein that is related to the interleukin-1 receptor but does not bind IL-1 by itself.

125I-Tyro-sauvagine: a novel high affinity radioligand for the pharmacological and biochemical study of human corticotropin-releasing factor 2 alpha receptors

Corticotropin-releasing factor (CRF) receptors encoded by two distinct genes have recently been identified and termed CRF1 and CRF2. CRF and the non-mammalian-related peptide sauvagine bind to and activate CRF1 receptors with high affinity and equal potency. Although CRF is significantly weaker at the CRF2 receptor, sauvagine retains its high affinity interactions with this receptor subtype. We expressed the human CRF1 and CRF2 receptor subtypes in stable cell lines and characterized 125I-Tyr0-sauvagine, a high affinity radiolabel suitable for the pharmacological and functional profiles of these proteins. 125I-Tyr0-sauvagine has high affinity (200-400 PM) for CRF1 receptors and demonstrates a pharmacological profile identical to that of 125I-Tyr0-ovine CRF-labeled CRF1 receptors. 125I-Tyr0-sauvagine binding to human CRF2 alpha receptors is saturable and of high affinity (KD = 100-300 PM) and demonstrates guanine nucleotide sensitivity typical of agonist binding to receptors. The pharmacological profile of 125I-Tyr0-sauvagine binding to CRF2 alpha receptors with respect to inhibition by CRF-related analogs is similar to the agonist profile of potencies obtained by measurements of cAMP production stimulated by these analogs in CRF2 alpha expressing cell lines and distinct from the profile of the CRF1 receptor subtype. Thus, the related nonmammalian peptides sauvagine and urotensin have high affinity and rat/ human CRF and ovine CRF have lower affinity for CRF2 receptors labeled with 125I-Tyr0-sauvagine. Because the distribution of CRF1 and CRF2 alpha receptors has been demonstrated to be distinct, suggesting selective functional roles for each receptor subtype, the ability to label CRF2 alpha receptors with 125I-Tyr0-sauvagine in vitro represents a unique opportunity for the discovery of subtype-selective nonpeptide ligands, which would presumably target different aspects of CRF-mediated disorders. We have thus identified and characterized a novel high affinity radioligand for the labeling of CRF2 receptors.

Cloning and characterization of an alternatively processed human type II interleukin-1 receptor mRNA

Two types of interleukin (IL)-1 receptors with three extracellular immunoglobulin-like domains, limited homology (28%), and different pharmacological characteristics termed type I and type II have been cloned from mouse and human cell lines. Both receptors exist in transmembrane and soluble forms; the soluble IL-1 receptor is thought to be post-translationally derived from cleavage of the extracellular portion of the membrane receptors. In preliminary cross-linking studies with radiolabeled IL-1, we found that monkey kidney COS1 cells express a soluble receptor with molecular mass of approximately 55-60 kDa, which is different from previously reported soluble IL-1 receptors. This soluble IL-1 receptor protein from COS1 cells was purified to homogeneity by affinity chromatography using recombinant IL-1beta as the ligand and shown to have an affinity for human 125I-IL-1beta (KD approximately 2-3 nM) comparable to the human type II IL-1 receptor (IL-1RII). The purified protein was microsequenced, and the sequence information was used to design primers to clone the COS1 IL-1RII using reverse transcription-coupled polymerase chain reaction; the DNA comparison with monkey COS1 and human IL-1RII indicate that they are 95% identical at the nucleic acid and amino acid levels. In addition, another cDNA, which represents an alternatively processed mRNA of the IL-1RII gene, was also cloned both from monkey COS1 and human Raji cells and was shown to have approximately 95% sequence identity between these species. While the cDNA of the novel alternatively processed gene has a 5' end identical to the IL-1RII, the 200 base pairs at the 3' end are different and the sequence predicts a soluble IL-1 receptor protein of 296 amino acids. Radioligand binding studies of the alternatively processed IL-1RII mRNA demonstrated kinetic and pharmacological characteristics similar to the known type II IL-1 receptor. COS7 cells (which lack IL-1 receptor) transfected with the transmembrane form of the human IL-1RII cDNA showed 125I-IL-1beta binding in both the membrane fractions and supernatant. In contrast, COS7 cells transfected with the alternatively processed human IL-1RII cDNA showed high affinity 125I-IL-1beta binding (Ki approximately 1.2 nM) predominantly in the supernatant; a very small amount of detectable membrane IL-1 binding activity was also observed presumably due to association of the soluble IL-1 receptor and membrane-integrated proteins. In cross-linking and ligand blot studies, the alternatively processed human IL-1RII cDNA-transfected COS7 cells expressed a soluble IL-1 receptor with molecular masses ranging from 60 to 160 kDa, further indicating the association between this soluble IL-1 receptor and other soluble proteins. In summary, we report the purification and characterization of a soluble IL-1 receptor expressed by COS1 cells and the cloning of an alternatively processed type II IL-1 receptor mRNA from both human and COS1 cells. The alternative splicing of a primary transcript leading to a secreted protein provides a potentially important mechanism by which soluble IL-1RII can be produced.

Measurement of corticotropin-releasing factor (CRF), CRF-binding protein (CRF-BP), and CRF/CRF-BP complex in human plasma by two-site enzyme-linked immunoabsorbant assay

The actions of human corticotropin-releasing factor (hCRF) in brain, pituitary, and plasma are modulated by a 37-kDa protein [CRF-binding protein (CRF-BP)] that binds to hCRF and neutralizes the peptide's biological activity, suggesting that only the free unbound peptide is biologically active. To accurately predict the biological consequences resulting from changes in total hCRF levels, we have developed two-site enzyme-linked immunosorbent assays (ELISAs) for hCRF-BP, free hCRF, and the hCRF-BP/hCRF complex. The assays were validated by measuring each factor in 1) maternal plasma at times when CRF and hCRF-BP levels are altered, and 2) plasma from normal elderly human subjects who have undergone a hCRF stimulation test. The hCRF-BP ELISA has a sensitivity of 2.7 fmol and a range of detection from 2.7-8000 fmol. Both the hCRF and hCRF-BP/ hCRF assays have a sensitivity of 0.4 fmol, with a useful range of detection from 0.4-40 fmol. Maternal plasma hCRF-BP levels remained unaltered between the 16-21 and 34-39 month gestational age groups. However, levels rose from 0.88 +/- 0.069 nmol/L in the 16-21 month gestational age group to 1.01 +/- 0.09 nmol/L in the 28-33 month gestational age group. Bound hCRF levels dramatically rose from undetectable at 16-21 months of gestation to 200 +/- 69 and 442 +/- 106 pmol/L in the 28-33 and 34-39 month gestational age groups, respectively. In comparison, free hCRF levels remained low throughout gestation, but dramatically rose to 318 +/- 120 pmol/L from 34-39 months of gestation. Binding site occupancy on the hCRF-BP decreased when bound and free hCRF levels were elevated. After treating the third trimester plasma sample with the high affinity hCRF-BP ligand, alpha-helical CRF-(9-41), all of the bound hCRF was displaced from the binding protein, and free hCRF levels rose from 87 to 284 pmol/L. The plasma hCRF-BP level was 0.9 +/- 0.08 nmol/L in normal human volunteers (10 men and 9 women; mean +/- SD age, 74.2 +/- 7.7 yr), decreased to 60% of basal levels 15 min after a bolus injection of 1 microgram/kg synthetic hCRF, and gradually returned to preinjection levels after 120 min. Conversely, bound and free hCRF levels increased from undetectable levels before hCRF injection to 0.58 +/- 0.03 nmol/L at 15 min and then rapidly decreased to undetectable levels at 120 min. These data validate the ELISAs in combination with high affinity hCRF-BP ligands for measuring bound and free hCRF in human plasma and suggest the utility of these assays for further determining alterations in peripheral CRF in conditions such as pregnancy.

A peroxovanadium compound induces Xenopus oocyte maturation: inhibition by a neutralizing anti-insulin receptor antibody

Synthetic peroxovanadium compounds are a new class of potent inhibitors of protein phosphotyrosine phosphatases. These compounds exhibit insulin-like activity both in vitro and in experimental animals. However, the molecular mechanism by which these compounds exert their biological effect is not well defined. We demonstrate here that several of these compounds induce Xenopus oocyte maturation in vitro, as indicated by germinal vesicle breakdown. Using one of these compounds for further studies, we show that the induction is dose-dependent and is accompanied by activation of maturation promoting factor as well as activation of Xenopus MAP kinase. Like insulin, bpV(pic) causes an acute accumulation of PI(3,4,5)P3 (phosphotidylinositol-3,4,5-trisphosphate), a product of PI 3-kinase. More importantly, bpV(pic)-induced oocyte maturation was abolished by microinjection of a neutralizing monoclonal anti-insulin receptor antibody (17A3) into oocytes or preincubation of oocytes with a PI 3-kinase inhibitor (wortmannin). These results suggest that bpV(pic) acts upstream of the Xenopus IGF-1 receptor in the induction of meiotic maturation, presumably by neutralizing an inhibitory protein tyrosine phosphatase(s) that may regulate the receptor. Finally, using an oocyte-follicle cell complex that responded to human chorionic gonadotropin (hCG) to undergo GVBD, we showed that injection of 17A3 anti-insulin receptor antibody into oocytes did not affect hCG-induced oocyte maturation.

The value of Tc-99m MIBI SPECT during isosorbide dinitrate infusion in assessment of viable myocardium in patients with myocardial infarction

Tc-99m MIBI myocardial SPECT has shown promise for evaluation of coronary artery disease. But its role in predicting myocardial viability is still under investigation. The purpose of this study was to evaluate the value of Tc-99m MIBI myocardial SPECT during isosorbide dinitrate (ISDN) infusion in the assessment of myocardial viability. Thirty-seven patients with previous myocardial infarction (the infarct age ranged from < or = 30 days to 900 days) were studied, of them 13 patients had Tc-99m MIBI studies before and after coronary artery bypass grafting (CABG). The results showed that out of 134 segments with hypoperfusion at resting SPECT, 56 segments (41.8%) had an increase in Tc-99m MIBI uptake during ISDN infusion. Among them, 17 segments (30.4%) were normalized, 6 segments (10.7%) were significantly improved and 33 segments (58.9%) were improved. The degree of improvement in perfusion was related to the age of the myocardial infarction. In 13 patients with CABG, of 31 segments with improvement in perfusion post CABG, 25 segments (80.6%) showed perfusion improvement during ISDN infusion, and of 28 segments with improved wall motion post CABG, 23 segments (82.1%) showed improvement in perfusion during ISDN infusion. Tc-99m MIBI SPECT during ISDN infusion may therefore be a useful approach for assessing myocardial viability.

[Inhibitory effects of protein kinase C inhibitors on tumor necrosis factor induced bovine pulmonary artery endothelial cell injuries]

The effects of protein kinase C(PKC) inhibitors 1-(5-isoquino-linylsulfonyl)-2-methylpeperazine (H-7) and quercetin on tumor necrosis factor (TNF) were studied in cultured bovine pulmonary artery endothelial cells (BPAEC) in vitro. Incubation of BPAEC with TNF caused a significant increase in percent lactate dehydrogenase (LDH) release, stimulation of EC-dependent neutrophils (PMN) adhesion to BPAEC and inhibition of BPAEC DNA synthesis and proliferation. All these were restored by both H-7 and quercetin. The IC50 of H-7 and quercetin was 9.7 and 10.8 mumol.L-1 for the inhibition of LDH% release; 19.5 and 16.7 mumol.L-1 for the inhibition of TNF-induced PMN-EC adhesion; 7.0 and 6.1 mumol.L-1 for TNF-induced inhibition of DNA synthesis and 8.7 and 11.36 mumol.L-1 for proliferation. These results suggest that PKC inhibitors H-7 and quercetin protect BPAEC from TNF induced injuries and PKC play an important role in EC activation by TNF.

A survey of moniliformin contamination in rice and corn from Keshan disease endemic and non-KSD areas in China

Keshan Disease (KSD) is an endemic heart disease and moniliformin (MF) has been suggested as one of the etiological factors. In this paper, thin layer chromatographic (TLC) and high pressure liquid chromatographic (HPLC) methods were used for the determination of MF in the rice and corn samples collected from KSD areas and non-KSD areas. One hundred and twenty-three rice samples were analyzed and showed MF contamination in only 8 samples (KSD areas: 8.4% positive; non-KSD areas: 2.5% positive) ranging from 73.6 to 265.3 ng/g (mean concentration: KSD areas 156.3 ng/g; non-KSD areas 179.5 ng/g). One hundred and four corn samples in KSD areas and non-KSD areas were determinated by HPLC method, 45.2% samples were contaminated with MF (KSD areas: 81.4%; non-KSD areas: 19.7%) ranging from 52.3 to 1116.0 ng/g (mean concentration: KSD areas 488.9 ng/g; non-KSD areas 457.4 ng/g). The results showed that the contamination of MF in grains were significantly different between rice and corn, but not between the grains from the KSD areas and non-KSD areas, then casting doubt on the role of MF as an etiological factor of KS.

Displacement of corticotropin releasing factor from its binding protein as a possible treatment for Alzheimer's disease

In Alzheimer's disease (AD) there are dramatic reductions in the content of corticotropin releasing factor (CRF), reciprocal increases in CRF receptors, and morphological abnormalities in CRF neurons in affected brain areas. Cognitive impairment in AD patients is associated with a lower cerebrospinal fluid concentration of CRF, which is known to induce increases in learning and memory in rodents. This suggests that CRF deficits contribute to cognitive impairment. The identification in post-mortem brain of CRF-binding protein (CRF-BP), a high-affinity binding protein that inactivates CRF, and the differential distribution of CRF-BP and CRF receptors, provides the potential for improving learning and memory without stress effects of CRF receptor agonists. Here we show that ligands that dissociate CRF from CRF-BP increase brain levels of 'free CRF' in AD to control levels and show cognition-enhancing properties in models of learning and memory in animals without the characteristic stress effects of CRF receptor agonists.

Molecular cloning of an amphibian insulin receptor substrate 1-like cDNA and involvement of phosphatidylinositol 3-kinase in insulin-induced Xenopus oocyte maturation

An insulin receptor substrate 1 (IRS-1)-like cDNA was isolated from a Xenopus ovary cDNA library by low-stringency hybridization using rat IRS-1 cDNA as a probe. The deduced amino acid sequence encoded by this cDNA (termed XIRS-L) is 67% identical (77% similar) to that of rat IRS-1. Significantly, all the insulin-induced tyrosine phosphorylation sites identified in rat IRS-1, including those responsible for binding to the Src homology domains of phosphatidylinositol (PI) 3-kinase, Syp and Grb2, are conserved in XIRS-L. Both mRNA and protein corresponding to the cloned XIRS-L can be detected in immature Xenopus oocytes. Recombinant XIRS-L protein produced in insect cells or a bacterial glutathione S-transferase fusion protein containing the putative PI 3-kinase binding site can be phosphorylated in vitro by purified insulin receptor kinase (IRK) domain, and the IRK-catalyzed phosphorylation renders both proteins capable of binding PI 3-kinase in Xenopus oocyte lysates. Another glutathione S-transferase fusion protein containing the C terminus of XIRS-L and including several putative tyrosine phosphorylation sites is also phosphorylated by IRK in vitro, but it failed to bind PI 3-kinase. Insulin stimulation of immature Xenopus oocytes activates PI 3-kinase in vivo [as indicated by an elevation of PI(3,4)P2 and PI(3,4,5)P3] as well as oocyte maturation (as indicated by germinal vesicle breakdown). Pretreatment of these oocytes with wortmannin inhibited insulin-induced activation of PI 3-kinase in vivo. The same treatment also abolished insulin-induced, but not progesterone-induced, germinal vesicle breakdown. These results (i) identify an IRS-1-like molecule in immature Xenopus oocytes, suggesting that the use of IRS-1-like Scr homology 2 domain-docking proteins in signal transduction is conserved in vertebrates, and (ii) strongly implicate PI 3-kinase as an essential effector of insulin-induced oocyte maturation.

Nitrate-augmented myocardial imaging for assessment of myocardial viability

201Tl myocardial perfusion imaging is presently done by several possible strategies. Stress/delayed redistribution, stress/redistribution/reinjection, and rest/redistribution imaging can be useful in the clinical assessment of myocardial viability. Unfortunately, the extent of myocardial viability may still be underestimated even by 201Tl reinjection imaging, compared with 18F-fluorodeoxyglucose positron emission tomography. 99mTc-labeled sestamibi imaging provides results similar to those of 201Tl imaging in the detection of coronary artery disease, but several previous studies suggest that stress/rest 99mTc-labeled sestamibi imaging significantly underestimates myocardial viability. Recently it has been reported that the administration of nitrates, before 201Tl reinjection, improves detection of defect reversibility. Several studies also suggested that administration of nitrates before the injection of 99mTc-labeled sestamibi significantly improved detection of reversibility with this agent, whereas additional studies showed further that this combination improves the predictive accuracy for recovery of left ventricular function and perfusion after coronary revascularization, compared with a standard rest 99mTc-labeled sestamibi study. Nitrate administration before the injection of 201Tl and 99mTc-labeled sestamibi may thus be a potentially attractive alternative for the evaluation of myocardial viability. Although the available results are encouraging, further studies are needed to evaluate the clinical value of 201Tl and 99mTc-labeled sestamibi imaging, in combination with nitrates, for predicting recovery of left ventricular dysfunction.

The isolation and structural elucidation of three new neolignans, piperulins [corrected] A, B, and C, as platelet activating factor receptor antagonists from Piper puberulum

Three new neolignans, piperulins [corrected] A [1], B [2], and C [3], were isolated from Piper puberulum. Their structures and relative stereochemistries were determined from spectral data and the X-ray crystallographic analysis of 1. Compounds 1 and 3 inhibit specific platelet activating factor receptor binding with IC50 values of 7.3 and 5.7 microM, respectively.

The heparin binding site of follistatin is involved in its interaction with activin

Whether the heparin-binding site of follistatin would interact with activin has been examined. When a mixture of recombinant human follistatin-288 (rhFS-288) and -315 (rhFS-315) was applied to an activin-coupled affinity column, followed by stepwise elution of the column using 4M urea, 8M urea, 1M guanidine-HCl and 2M guanidine-HCl, rhFS-315 was eluted with 4M urea, while rhFS-288 was eluted with 2M guanidine-HCl. This finding implies that the carboxylterminal 27 amino acid extension of rhFS-315, which is not present in rhFS-288, affects the binding of follistatin with activin. Addition of heparin (50 micrograms/ml) to the elution solvent caused rhFS-288 to elute with 4M urea, whereas rhFS-315 was not affected. These data suggest for the first time that these two structurally related follistatin molecules interact with activin by different modes of binding and, in the presence of heparin, the interaction of rhFS-288 with activin is indistinguishable from that of rhFS-315. Two analogs of rhFS-288 mutated at the heparin binding site were eluted with 8M urea or 1M guanidine-HCl, distinct from the elution profile of the intact rhFS-288. These results indicated that mutation at the heparin binding site alters the activin binding affinity. In addition, bioassay of the two mutants showed that they were less potent than the rhFS-288. These findings suggest that the heparin binding site of follistatin also contributes to its binding for activin, and heparin may play an important role in the bioactivity of follistatin.

[Preliminary study on pharmacologic action of Ligustrum japonicum]

The results of treatment with the Ligustrum japonicum Thunb. Var. Pubescens Koidz (LJ) in rabbits' model of hyperlipemia and atherosclerosis was observed. The results showed: (1) By the end of first to third month, the levels of serum TL and TC in groups B,C were lower than that of group A and there was significant difference between them (P < 0.05), the level of serum TG in groups B,C was lower than that of group A too, but there was no significant difference between them (P > 0.05). (2) By the end of first and second month, the level of serum LPO in groups B,C was lower than that of group A and there were significant difference between them (P < 0.05, 0.01), while there was no significant difference between group B and group C (P > 0.05). (3) The rabbits were sacrificed by the end of third month, arteriosclerotic area of aorta in groups B,C were less than that of group A, and that of group B was even less than group C, there was significant difference between group A and B (P < 0.01). (4) By the end of third month, the level of HCT in groups B,C was lower than that of group A and there was significant difference between them (P < 0.05), but there was no significant difference between group B and group C (P > 0.05). These results showed that LJ could lower the levels of serum TL, TC, LPO, HCT and anti-arteriosclerosis as well, it could prevent cerebro- and cardio-vascular disease as the clofibrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Extrapituitary actions of gonadotropin-releasing hormone: stimulation of insulin-like growth factor-binding protein-4 and atresia

To understand how the intrinsic GnRH system functions in the ovary, we tested the effects of GnRH agonist (GnRH-a) on insulin-like growth factor-binding protein-4 (IGFBP-4) production, a novel marker of atresia. We also tested the ability of GnRH-a to stimulate atresia in vivo. When rat granulosa cells were cultured in defined medium for 2 days (controls), relatively large amounts of the 24,000 relative molecular mass IGFBP-4 accumulated in the medium. FSH (100 ng/ml) inhibited control IGFBP-4 protein levels and stimulated IGFBP-4 protease activity. GnRH-a increased (up to 4-fold) IGFBP-4 accumulation in the medium (ED50 = 1 x 10(-10) M), and the effect was blocked by a GnRH antagonist. Neither GnRH-a nor its antagonist had a detectable effect on protease activity. In coincubation experiments, GnRH-a effectively inhibited (ED50 = 3 x 10(-11) M) the FSH responses, and the effect of GnRH-a was blocked by GnRH antagonist. A 6-day time-course experiment showed that IGFBP-4 accumulation in control cultures remained constant for 2 and 4 days, after which it was undetectable. FSH (100 ng/ml) produced no measurable IGFBP-4 over the 6-day time course. The levels of IGFBP-4 increased markedly during the first 2 days of GnRH-a treatment, but were not significantly different from control levels on days 4 and 6. Similar results were obtained when cells were treated with FSH plus GnRH-a. Treating immature hypophysectomized estrogen-primed rats with GnRH-a in vivo caused a rapid and dramatic decrease (average, 60%) in the mitotic index of the granulosa cells of all preantral follicles (healthy and atretic) and increased pyknosis. These results demonstrate that 1) GnRH-a stimulates the expression of IGFBP-4 protein in rat granulosa cells in vitro; 2) GnRH-a abolishes the ability of FSH to inhibit IGFBP-4 expression and induce IGFBP-4 protease activity; and 3) GnRH-a stimulates atresia in preantral follicles in vivo. These results support the hypothesis that autocrine/paracrine secretion of ovarian GnRH might cause atresia by mechanisms involving increased IGFBP-4 synthesis.

Rate of change of left ventricular ejection fraction during exercise is superior to the peak ejection fraction for predicting functionally significant coronary artery disease

OBJECTIVE

To detect and characterise rapid temporal changes in the left ventricular response to exercise in patients with ischaemic heart disease and to relate these changes to the functional severity of coronary artery disease.

BACKGROUND

The gamma camera does not allow the detection of rapid changes in cardiac function during exercise radionuclide ventriculography, the monitoring of which may improve the assessment of patients with ischaemic heart disease.

METHODS

A miniature nuclear probe (Cardioscint) was used to monitor continuously left ventricular function during exercise in 31 patients who had coronary angiography for suspected coronary artery disease. A coronary angiographic jeopardy score was calculated for each patient.

RESULTS

The coronary jeopardy score ranged from 0 to 12 (median 4). Ejection fraction fell significantly during exercise from 46% to 34%. Patients were divided into two groups based on the response of their ejection fraction to exercise. In 14 patients (group I), the peak change in ejection fraction coincided with the end of exercise, whereas in the other 17 patients (group II) the peak change in ejection fraction occurred before the end of exercise, resulting in a brief plateau. The peak change in ejection fraction and the time to its occurrence were independent predictors of coronary jeopardy (r = -0.59, p < 0.001 for peak change and r = -0.69, p < 0.001 for time to that change). The rate of change in ejection fraction was the strongest predictor of coronary jeopardy (r = -0.81, p < 0.001). In group I the peak change in ejection fraction was a poor predictor severity of coronary disease (r = -0.28, NS), whereas the time to peak and the rate of change in ejection fraction were good predictors (r = -0.65 and r = -0.73, p < 0.01). In group II the peak, the time to the peak, and the rate of change in ejection fraction were good predictors of coronary jeopardy (r = -0.75, r = -0.61, and r = -0.83, p < 0.01).

CONCLUSION

The rate of change of ejection fraction during exercise can be assessed by continuous monitoring of left ventricular function with the nuclear probe, and is the best predictor of functionally significant coronary artery disease.

99mTc-antimyosin antibody imaging for the detection of acute myocardial infarction in human beings

111In-antimyosin imaging is a highly sensitive and specific technique for the detection of myocardial necrosis. Two new methods of labeling antimyosin with 99mTc have been developed, and were compared with the standard 111In-antimyosin imaging technique in 29 patients with acute myocardial infarction. Fourteen patients (group I) received directly labeled 99mTc-antimyosin, and 15 (group II) were given RP-1 conjugated 99mTc-antimyosin. 99mTc-antimyosin imaging was performed at 6, 12, and 24 hours, and 111In-antimyosin imaging was done at 24 and 48 hours following injection. The images were interpreted by three blinded observers. In group I, 99mTc-antimyosin uptake could be detected in 3, 6, and 12 cases at 6, 12, and 24 hours, respectively, compared with only 8 cases at 24 hours with 111In-antimyosin. At 48 hours all patients showed 111In-antimyosin uptake. In group II, 99mTc-antimyosin uptake could be detected in 2, 3, and 6 cases at 6, 12, and 24 hours, respectively, compared with 8 and 12 cases at 24 and 48 hours, respectively, with 111In-antimyosin. Gated blood pool studies could be obtained in all patients following 99mTc-antimyosin injection and could be used to identify regional wall motion abnormalities. The plasma half-lives of 99mTc-antimyosin in group I and group II were 2.67 +/- 0.3 hours and 4.23 +/- 0.3 hours, respectively, and the plasma half-life of 111In-antimyosin was 6.3 +/- 0.4 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

[An observation on the regularity of mould invasion into sugarcane and its prevention]

The factors that influence mould invasion into sugarcane were investigated. Results showed sales pattern, storage condition, and duration of storage for sugarcane were the major influential factors to its mildew. Antiseptic agents had no obvious protective effects on mould invasion. According to authors' experiments, sugarcane can be stored for no more than 3 weeks to prevent from mildew. The outward appearance of sugarcane changed with its contamination of 3-NPA. A simple method for detecting mildew in sugarcane was also described in the paper.

Effects of triptonide on mouse immune functions

Triptonide (Tri) extracted from Tripterygium wilfordii Hook inhibited the proliferation of mouse splenocytes induced by suboptimal concentration of concanavalin A or lipopolysaccharide at concentrations of 0.02, 0.1, and 0.5 microgram.ml-1. It showed a suppressive effect on one way mixed lymphocyte culture (MLC) at 0.1-0.4 microgram.ml-1. The lymphocytes harvested from the first Tri (0.4 microgram.ml-1)-containing MLC inhibited the second MLC after being washed and irradiated with 60Co source (30 Gy). Serum anti-sheep red blood cell antibody (hemolysin) formation and clearance of charcoal particles were also suppressed by Tri in vivo. Although delayed hypersensitivity (DH) reaction to dinitrofluorobenzene (DNFB) was inhibited by Tri 1.2, 2.5, and 5.0 mg.kg-1 (ip, qd x 5 d), the spleen cell interleukin-2 secretion activities of these mice were not suppressed. Graft vs host reaction (GVHR) was not inhibited by Tri 2.5 and 5.0 mg.kg-1 (ig, qd x 5 d). Helper T cells (Th)/suppressor T cells (Ts) ratio was reduced at 2.5 mg.kg-1. The effects of Tri on mouse thymus and spleen weight were related to the age. Tri (1.2, 2.5, 5.0 mg.kg-1) had no effect on thymus and spleen weights in 8-wk-old mice. However, it increased the thymus and spleen weights in 12-wk-old mice at doses of 1.2 and 2.5 mg.kg-1. The data indicated that Tri had extensive suppressive effects on mouse immune function and its mechanism may be related to the reduction of Th/Ts ratio and the induction of Ts cells.

Development of specific antibodies to rat insulin-like growth factor-binding proteins (IGFBP-2 to -6): analysis of IGFBP production by rat granulosa cells

Six insulin-like growth factor-binding proteins (IGFBPs) have been isolated and their cDNAs cloned in the rat and human species. The next step is to develop antibodies to each IGFBP. Toward this goal, we generated rabbit polyclonal antibodies to rat IGFBP-2, -4, -5, and -6, using synthetic peptide fragments of the IGFBPs. A rat IGFBP-3 polyclonal antibody was prepared in a previous study using the native protein. Western immunoblotting demonstrated that the IGFBP-2, -3, -4, -5, and -6 antibodies were highly specific for their respective antigens. The elicited antisera were used to study IGFBP production in primary cultures of rat granulosa cells grown in serum-free medium for 72 h. Ligand blotting with 125I-labeled IGF-I and IGF-II revealed two bands migrating at 29 and 24 kilodaltons (kDa) in the medium of untreated control cells, whereas no bands were detectable in medium from cells incubated with 100 ng/ml FSH. Western blotting of control medium with all of the IGFBP antibodies revealed that the IGFBP-4 antibody stained two bands at 28 and 24 kDa, and the IGFBP-5 antibody stained two bands at 30 and 29 kDa. By contrast, these bands were absent in medium from FSH-stimulated cells; instead, two lower molecular mass bands of 21.5 and 17.5 kDa were detected with the IGFBP-4 antibody, and a 21-kDa band was seen with the IGFBP-5 antibody. The same 21.5- and 17.5-kDa bands were seen when exogenously added IGFBP-4 was incubated with the FSH-conditioned medium, whereas untreated medium did not degrade the added IGFBP-4. Incubation with the conditioned medium also degraded exogenous IGFBP-5 to yield a 21-kDa band. By contrast, medium from control cells did not degrade the exogenous IGFBP-5. This finding indicates that FSH induced the production of a protease from granulosa cells that degraded IGFBP-4 and -5 in the culture medium. No IGFBPs were detectable in medium from control or FSH-treated cells using the IGFBP-2, -3, and -6 antibodies. Northern blotting analysis of the same control granulosa cell cultures revealed a 2.6-kilobase and a 6.0-kilobase transcript for IGFBP-4 and -5, respectively; however, the IGFBP-4 and -5 mRNAs were essentially undetectable in FSH-treated cell cultures. To determine the effects of the IGFBPs on steroidogenesis, dose-response experiments were performed with IGFBP-4 and -5.(ABSTRACT TRUNCATED AT 400 WORDS)

Prognostic value of noninvasive cardiac tests in the assessment of patients with peripheral vascular disease

Two hundred thirty-six patients with peripheral vascular disease were prospectively studied to assess whether noninvasive cardiac investigations could predict prognosis better than simple clinical assessment. Clinical history, examination and resting electrocardiography were considered in all patients; exercise electrocardiography, Holter monitoring, radionuclide ventriculography and dipyridamole thallium imaging were performed in a subgroup of 168 patients. Follow-up for 6 to 30 months revealed major cardiac events in 21 patients. Cox survival analysis showed that clinical evidence of prior coronary artery disease was the best variable from clinical assessment that predicted cardiac events, with no other clinical variable adding to the statistical model. When variables from noninvasive cardiac assessment were added to the model, which included clinical evidence of coronary artery disease, dipyridamole thallium heart:lung ratio and left ventricular ejection fraction added significantly and incrementally to the prediction of cardiac events. Results of exercise electrocardiography or Holter monitoring did not add significantly. It is concluded that high lung uptake of thallium during dipyridamole stress, and impaired left ventricular ejection fraction help to identify patients with peripheral vascular disease who are at high cardiac risk, and should therefore be used for selecting subsequent cardiovascular medical, surgical and anesthetic management.