[Current status and distribution of deafness in the elderly in several cities in China]

OBJECTIVE

To survey the current status and distribution of deafness and its effect on daily life activities in the old population.

METHODS

Eight thousand two hundred and fifty-two elderly aged 60 years and above in the urban and rural areas of Beijing, Shanghai, Guangzhou, Chengdu, Xi'an and Shenyang were investigated, using a clustered random sampling methods.

RESULTS

Overall crude prevalence of deafness in the elderly was found to be 33.7%, but the self-reported crude prevalence was low, only 47.1% when shown by medical examination. Crude prevalence rates were increasing with ageing, with 21.6%, 30.0%, 35.6%, 42.6%, 55.5% and 61.6% respectively (P < 0.01) in the age groups of 60-, 65-, 70-, 75-, 80-, 85- years old. Rate of deafness was highest in Beijing (58.5%), among the in-house workers (48.9%) and the lowest in scientists, teacher and health workers (28.5%). Logistic regression analysis showed that the crude prevalence was related to ageing, profession and area (P respective < 0.01).

CONCLUSION

The prevalence of deafness was high in the elderly which increased with ageing with different areas, professions and the level of education. It was lower when self-reported than shown by medical examination. Prevention and treatment of deafness in the elderly should be strengthened.

Near-Infrared Spectrum of the A(2)Pi(i)-X(2)Sigma(+) (2,0) Band of CN Studied by Concentration Modulation Laser Spectroscopy

The rotational structure of (2,0) vibrational band of A(2)Pi(i)-X(2)Sigma(+) transition of CN has been studied by concentration-modulation laser spectroscopy using a Ti:sapphire laser. The CN radical was produced in the ac glow discharge of acetonitrile with helium as the carrier gas. All 12 branches including four new branches have been observed and measured with an absolute accuracy of 0.007 cm(-1) in the region 12 450-12 750 cm(-1). Analysis of the spectra has led to improved molecular parameters of the A(2)Pi(i) (v' = 2) state. Copyright 2001 Academic Press.

Changes of reliability and efficiency of micronucleus bioassay in Vicia faba after exposure to metal contamination for several generations

Mitotic root micronucleus (MCN) frequency in Vicia faba as a bioassay, is primarily based on the extent of the sentinel Vicia response in terms of cytogenetic damage quantitatively or qualitatively to indicate the presence of mutagenic contaminants. This paper describes an investigation designed to assess changes in MCN frequencies of Vicia faba from three generation plants obtained, respectively from a reference site (RS) and a metal-contaminated experimental field (EF) in the bioassay of mutagenic Cd(2+) and NaN(3). The background value, dose-response to Cd(2+) and to NaN(3) in three generation (F(1), F(2) and F(3)) plants of the EF and the initial (F(0)) plants were determined in terms of MCN frequencies. With more generations of growing Vicia plants in the EF, a higher background value of MCN frequency, a lower slope value in the regression equation, a smaller ratio of MCN frequency between the control and treatment in the same generation and larger perturbation values were observed. This denotes that the decreased reliability and efficiency are represented in Vicia plants from the EF if the plants are used as sentinels in the bioassay of mutagenic Cd(2+) and NaN(3). It was concluded that the Vicia MCN bioassay should be used as an endpoint biomarker acceptable in biomonitoring environmental mutagens when the sentinel plants were collected from clean areas. Because no place is absolutely without pollutants, it is suggested that several seed stock centers should be established for providing sentinel Vicia if Vicia MCN bioassay is used as a biomarker to identify the global environmental status.

[Prevalence of prostatic hyperplasia and its relative factors in six cities of China in 1997]

OBJECTIVE

To study crude prevalence and distribution of the elderly prostatic hyperplasia.

METHODS

Three thousand three hundred and sixty-one elderly aged 60 years and above in the urban and rural areas of Beijing, Shanghai, Guangzhou, Chengdu, Xi'an and Shenyang were investigated, using clustered random sampling methods.

RESULTS

The crude prevalence of prostatic hyperplasia was found to be 43.68% with an increase with ageing (P < 0.01). The crude prevalence rates of prostatic hyperplasia among the elderly of 60-, 65-, 70-, 75-, 80-, 85- years old were 34.48%, 40.27%, 46.77%, 51.44%, 57.32% and 60.19% respectively (P < 0.01). Rates in the urban and rural areas were 46.79%and 39.64% respectively. The crude prevalence of urban areas was higher than that of rural areas (P < 0.01) and was found higher in Beijing (63.28%) and Guangzhou (54.28%), (P < 0.01). The crude rates prevalence of managers (54.88%), teachers and business men (55.17%) were in general higher than the prevalence of the workers (41.29%) and peasant (37.26%). Logistic regression analysis showed that the crude prevalence was related to ageing, profession and residential areas (P respective < 0.01).

CONCLUSION

The prevalence of prostatic hyperplasia was higher in the elderly and became a common disease of the male elderly in China. Prevention and treatment of prostatic hyperplasia in the elderly should be strengthened.

[Endovascular embolization treatment of intracranial aneurysms]

OBJECTIVE

To evaluate the effect of endovascular embolization of intracranial aneurysms with detachable coil and detachable balloon and emphasize the mainpoint of embolic technique.

METHODS

194 patients underwent complete cerebral angiography using microcatheter under DSA imaging. 80 cases with 90 aneurysms were emboliced by MDS, 69 cases with 71 aneurysms were emboliced by GDC. 37 of 40 giant aneurysms were emboliced by detachable balloon, 2 aneurysms by GDC, 1 by MDS.

RESULTS

194 patients with 201 aneurysms were cured successfully; 191 cases recovered clinically, 3 patients died. 187 aneurysms achieved 100% embolization, 8 with 95% embolization, 4 with 90% embolization, and 1 with 80% embolization. Four aneurysms reputured during the embolization, 4 patients had cerebral infarction, one patient died by hard-treated cerebral vasospasm which was affected by microcoil escape. Two recurrent cases were cured by second GDC embolization.

CONCLUSIONS

The method of endovascular embolization to treat intracranial aneurysm is safe, reliable and effective. Those cases with giant aneurysms will have high recurrence in the future. Patients who suffer from SAH repeatedly may have great possibility of aneurysm rupture during embolization.

[Root excretion and plant resistance to metal toxicity]

Reducing the availability and toxicity of metal pollutants before they enter plant body is one of the main mechanisms of plant resistance to metals. Root system is the first entrance of metal pollutants from soil into plant. It can excrete organic acids, amino acids, sugars, growth substances etc. into rhizosphere. Root excretion affects the metal absorption by plant through changing the physical and chemical characters(such as pH, Eh) of rhizosphere. The metal pollutants are detained outside the roots by chelation, complexation and disposition with root exudates. The quantity and activity of metals in rhizosphere are changed by root exudates through changing the composition, activity and excretion of microbes there. After reviewing the research advances on root excretion and plant resistance to metals, the authors pointed out the existing problems and the major topics and significance of further research.

Phosphatidylinositol 3-kinase is required for insulin-like growth factor-I-induced vascular smooth muscle cell proliferation and migration

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation and directed migration. The mitogenic and chemotactic actions of IGF-I are mediated through the IGF-I receptor, but how the activation of the IGF-I receptor leads to these biological responses is poorly understood. In this study, we examined the role of phosphatidylinositol 3-kinase (PI3 kinase) in mediating the mitogenic and chemotactic signals of IGF-I. IGF-I treatment resulted in a significant increase in phosphotyrosine-associated PI3 kinase activity in cultured primary VSMCs. To determine whether insulin receptor substrate (IRS)-1, -2, or both are involved in IGF-I signaling in VSMCs, cell lysates were immunoprecipitated with either an anti-IRS-1 or an anti-IRS-2 antibody, and the associated PI3 kinase activity was determined. IGF-I stimulation resulted in a significant increase in IRS-1- but not IRS-2-associated PI3 kinase activity, suggesting that IGF-I primarily utilizes IRS-1 to transmit its signal in VSMCs. The IGF-I-induced increase in IRS-I-associated PI3 kinase activity was concentration dependent. At the maximum concentration (50 ng/mL), IGF-I induced a 60-fold increase. This activation occurred within 5 minutes and was sustained at high levels for at least 6 hours. IGF-I also caused a concentration-dependent and long-lasting activation of protein kinase B (PKB/Akt). Inhibition of PI3 kinase activation by LY294002 or wortmannin abolished IGF-I-stimulated VSMC proliferation and reduced IGF-I-directed VSMC migration by approximately 60%. These results indicate that activation of PI3 kinase is required for both IGF-I-induced VSMC proliferation and migration.

Purification, characterization, and bioassay of prolactin and growth hormone from temperate basses, genus Morone

Prolactin (PRL) and two variants of growth hormone (GH), purified from pituitaries of striped bass (Morone saxatilis) and its hybrid with white bass (M. saxatilis x M. chrysops) by gel filtration chromatography under alkaline conditions followed by reversed-phase high pressure liquid chromatography, appear similar between species. Both the minor (GH I) and the major (GH II) forms of purified GH appeared as single bands (M(r) approximately 23,000) after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, as did the purified PRL (M(r) approximately 24,000). The molecular weights of GH II and PRL determined by MALDI TOF mass spectroscopy were 21.2 and 21.3 kDa, respectively. In Western blotting experiments, an antiserum against tilapia (Oreochromis mossambicus) 24K PRL specifically recognized Morone PRL, while an antiserum against tilapia GH specifically recognized Morone GH I and II. Chemical identities of the putative PRL and GH I were further confirmed by N-terminal peptide sequencing, while internal sequence analysis was performed on GH II because it was blocked at its N-terminus. Over a stretch of 29 amino acids, Morone PRL was found to be 76% identical to tilapia 24K PRL, 72% identical to tilapia 20K PRL, 72% identical to chum salmon (Oncorhynchus keta) PRL I, and 69% identical to eel (Anguilla japonica) PRL I. Alignment of the hybrid striped bass GH sequences with those of several other advanced marine teleosts indicated 75-85% sequence identity for GH I (40 amino acids) and 95-98% identity for GH II (45 amino acids). Biological activity of striped bass GH II was confirmed using a heterologous in vitro assay of insulin-like growth factor I mRNA production by coho salmon (On. kisutch) hepatocytes. An in vivo bioassay, involving hypophysectomy of hybrid striped bass and treatment of the fish maintained in fresh water with homologous PRL, confirmed that the purified striped bass PRL was also bioactive.

Insulin-like growth factor (IGF)-I regulates IGF-binding protein-5 gene expression through the phosphatidylinositol 3-kinase, protein kinase B/Akt, and p70 S6 kinase signaling pathway

Expression of the insulin-like growth factor-binding protein 5 (IGFBP-5) gene in vascular smooth muscle cells is up-regulated by IGF-I through an IGF-I receptor-mediated mechanism. In this study, we studied the possible involvement of the mitogen-activated protein kinase (MAPK) and PI 3-kinase signaling pathways in mediating IGF-I-regulated IGFBP-5 gene expression. The addition of Des(1-3)IGF-I, an IGF analog with reduced affinity to IGFBPs, resulted in a transient activation of p44 and p42 MAPK. Inhibition of the MAPK activation by PD98059, however, did not affect IGF-I-stimulated IGFBP-5 expression. Des(1-3)IGF-I treatment also strongly activated PI 3-kinase. This activation was probably mediated through IRS-1, because IGF-I stimulation resulted in a significant increase in IRS-1- but not IRS-2-associated PI 3-kinase activity. This activation occurred within 5 min and was sustained at high levels for over 6 h. Likewise, Des(1-3)IGF-I caused a long lasting activation of PKB/Akt and p70(s6k). When LY294002 and wortmannin, two specific inhibitors of PI 3-kinase, were added with Des(1-3)IGF-I, the IGF-I-regulated IGFBP-5 expression was negated. The addition of rapamycin, which inhibits IGF-I-induced p70(s6k) activation, significantly inhibited IGF-I-regulated IGFBP-5 gene expression. These results suggest that the action of IGF-I on IGFBP-5 gene expression requires the activation of the PI 3-kinase-PKB/Akt-p70(s6k) pathway but not the MAPK pathway in vascular smooth muscle cells.

Insulin-like growth factor binding protein 2 is a growth inhibitory protein conserved in zebrafish

Fish serum contains several specific binding proteins for insulin-like growth factors (IGFBPs). The structure and physiological function of these fish IGFBPs are unknown. Here we report the complete primary sequence of a zebrafish IGFBP deduced from cDNA clones isolated by library screening and rapid amplification of cDNA ends. The full-length 1,757-bp cDNA encodes a protein of 276 aa, which contains a putative 22-residue signal peptide and a 254-residue mature protein. The mature zebrafish IGFBP has a predicted molecular size of 28,440 Da and shows high sequence identity with human IGFBP-2 (52%). The sequence identities with other human IGFBPs are <37%. Chinese hamster ovary cells stably transfected with the zebrafish IGFBP-2 cDNA secreted a 31-kDa protein, which bound to IGF-I and IGF-II with high affinity, but did not bind to Des(1-3)IGF-I or insulin. Northern blot analyses revealed that the zebrafish IGFBP-2 transcript is a 1.8-kb band expressed in many embryonic and adult tissues. In adult zebrafish, IGFBP-2 mRNA levels were greatly reduced by growth hormone treatment but increased by prolonged fasting. When overexpressed or added to cultured zebrafish and mammalian cells, the zebrafish IGFBP-2 significantly inhibited IGF-I-stimulated cell proliferation and DNA synthesis. These results indicate that zebrafish IGFBP-2 is a negative growth regulator acting downstream in the growth hormone-IGF-I axis.

Regulation of lysyl oxidase, collagen, and connective tissue growth factor by TGF-beta1 and detection in human gingiva

Gingival overgrowth is characterized by excess extracellular matrix accumulation and elevated levels of cytokines, including transforming growth factor-beta1 (TGF-beta1). The functional relationships between altered cytokine levels and extracellular matrix accumulation have not been extensively investigated in gingival cells and tissues. Lysyl oxidase catalyzes the final known enzymatic step required for cross-linking collagen and elastin in the synthesis of a functional extracellular matrix. This study investigated the regulation by TGF-beta1 of lysyl oxidase and its collagen and elastin substrates in early passage human gingival fibroblasts. In addition, TGF-beta1 regulation of connective tissue growth factor (CTGF) was assessed in human gingival cells and tissues. The results show that TGF-beta1 increases lysyl oxidase enzyme activity and mRNA levels for lysyl oxidase and alpha-1-type I collagen, but not elastin, in a dose- and time-dependent manner. Maximal stimulation of lysyl oxidase activity and mRNA levels for both lysyl oxidase and collagen occurs after 48 hours of treatment of gingival fibroblastic cells with 400 pM of TGF-beta1. This study shows for the first time that CTGF mRNA and protein are strongly and rapidly induced by TGF-beta1 in human gingival fibroblasts. Exogenous addition of 1 to 50 ng/ml CTGF to gingival fibroblasts stimulates production of lysyl oxidase enzyme activity up to 1.5-fold after 48 hours, and 50 ng/ml CTGF stimulated insoluble collagen accumulation 1.5- to 2.0-fold after 4, 11, and 18 days of treatment. It is interesting to note that the addition of CTGF-blocking antibodies in the presence of TGF-beta did not block TGF-beta stimulation of collagen mRNA levels. Thus, although CTGF itself contributes to increased insoluble collagenous extracellular matrix accumulation, CTGF does not mediate all of the effects of TGF-beta1 on stimulation of collagen mRNA levels in human gingival fibroblasts. Immunohistochemistry studies of gingival overgrowth tissue samples indicate for the first time detectable levels of CTGF protein in Dilantin-induced hyperplasia tissues also positive for TGF-beta1. CTGF was not found in TGF-beta1-negative samples. In addition, extracellular lysyl oxidase protein was detected in vivo. Taken together, these studies support mostly independent roles for TGF-beta1 and CTGF in stimulating collagenous extracellular matrix accumulation in human gingival fibroblasts and tissues.

Down-regulation of protein kinase C inhibits insulin-like growth factor I-induced vascular smooth muscle cell proliferation, migration, and gene expression

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation, directed migration, differentiation, and apoptosis. The signaling mechanisms used by IGF-I to elicit these actions, however, are not well defined. In this study, we examined the role(s) of protein kinase C (PKC) in mediating the IGF-I actions in cultured porcine VSMCs. Out of the eleven known members of PKC family, PKC-alpha, -betaI, -epsilon, -eta, -lambda, -theta, and -zeta, were detectable by Western immunoblot analysis in these cells. Further analysis indicated that the subcellular distribution of several PKC isoforms is regulated by IGF-I. While IGF-I stimulated membrane translocation of PKC-eta, -epsilon, and -zeta and regulated the cytosolic levels of PKC-betaI, it had no such effect on PKC-alpha and -lambda. To examine whether PKC activation is required for the IGF-I-regulated biological responses, phorbol myristate acetate (PMA) and GF109203X were used to down-regulate or inhibit PKC activity. Both PMA (1 microM) and GF109203X (20 microM) nearly completely suppressed the total PKC activity after a 30-min incubation (> 90%), and this inhibition lasted for at least 24 h. Down-regulation or inhibition of PKC activity abolished the IGF-I-induced DNA synthesis, migration and IGFBP-5 gene expression. In contrast, the IGFBP-5 expression induced by forskolin was unaffected by PKC down-regulation or inhibition, suggesting that PKC activation is required for the IGF-regulated but not the cAMP-regulated events. Because the actions of IGF-I on DNA synthesis and IGFBP-5 gene expression in VSMCs have been shown to be mediated through the phosphatidylinositol 3-kinase (PI3 kinase) signaling pathway in porcine VSMCs, the potential role of PKC in IGF-I-induced activation of PI3 kinase and PKB/Akt were examined. Treatment with either PMA or GF109203X did not significantly affect the effects of IGF-I on PI3 kinase activation or PKB/Akt phosphorylation. These results indicated that PKC-betaI, -eta, -epsilon, and -zeta may play an essential role(s) in IGF-I regulation of VSMC migration, DNA synthesis and gene expression, and that these PKC isoforms may either act independently of the PI3 kinase pathway or act further downstream of PKB/Akt in the IGF signaling network.

Changes in phospholipids and free fatty acids in the brains of mice preconditioned by hypoxia

Changes in the composition and contents of phospholipids and free fatty acids were observed and compared in three groups: (A) unpreconditoned normal controls, (B) exposure to 1 run of hypoxia and (C) exposure to 4 runs of hypoxia. In group B, the content of phosphatidyl ethanolamine (PE), phosphatidyl serine (PS) and free fatty acids (FFAs) increased significantly and the content of phosphatidyl choline (PC) and sphingomyelin (SM) decreased significantly. While in group C the content of PE, PS, PC and FFAs changed significantly when compared with that of group B, all phospholipid (except SM) and FFA contents tended to decrease to the level of group A. No new FFA was seen in the brain homogenates in any of the three groups. These results suggest that the changes in the content of mouse brain phospholipids and FFAs may be adaptive and involved in the animals' tolerance to hypoxia.

Changes of superoxide dismutase, glutathione perioxidase and lipid peroxides in the brain of mice preconditioned by hypoxia

We have developed an animal model of hypoxic preconditioning and assumed that oxygen radicals and their endogenous scavenging enzymes may play an important role in the preconditioning. To test this hypothesis, activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the content of lipid peroxides (LPO) were measured during the preconditioning. Compared with unpreconditioned control animals, in animals exposed to hypoxia only once, the activities of SOD and GSH-Px in whole brain were found to be significantly decreased while the LPO content in the hippocampus significantly increased. However, those in animals exposed to 4 runs of hypoxia tended to return to control levels and were lower than those in animals exposed to 1 and 2 runs of hypoxia. Our results indicate that the oxygen radicals and their specific scavenging enzymes seem to be involved in the development of tolerance to hypoxia.

Intermittent stimulation enhances function of conditioned muscle

Skeletal muscle is highly adaptable in that its metabolic and contractile characteristics are largely regulated by its pattern of use. It is known that muscle phenotype can be manipulated via chronic electrical stimulation to enhance fatigue resistance at the expense of contractile power. Type 2A fibers are fatigue resistant, powerful, and considered most desirable for cardiac assist purposes. We have found that 12-wk of intermittent-burst stimulation produces a high percentage of 2A fibers and increases fatigue resistance and power in rabbit latissimus dorsi muscle. Fixed-load endurance tests were used to quantify fatigue resistance among normal and trained muscle groups. Control muscles were found to fatigue completely within 10-20 min. Muscles stimulated continuously for 6 wk retained 35% (71.5 +/- 19.5 g. cm) of their initial stroke work at 40 min. Muscles stimulated 12 h/day for 12 wk had the highest initial stroke work (449.7 +/- 92.4 g. cm) and the highest remaining stroke work (234.7 +/- 50.1 g. cm) at 40 min. Results suggest that employing regular resting periods during conditioning preserves strength in fatigue-resistant muscle.

Antigen changes of monoclonal antibody MSH27 in process of post-testicular maturation (in mice)

An anti-mouse spermatozoon monoclonal antibody, MSH27, as well as its purified antigen, can block sperm-egg membrane fusion. As a candidate protein for sperm-egg membrane fusion, the sperm antigen was investigated in the process of post-testicular maturation (PTM). The molecule was produced in testes and located on the plasma membrane of the postacrosomal area of the spermatozoon. However, the epitope recognized by the MSH27 (MSH27Ep) was not exposed until the occurrence of the acrosome reaction. In the process of fertilization, spermatozoa must complete the acrosome reaction before penetrating across the zona pellucidas (ZPs) to approach the plasma membrane of eggs. The effects of the acrosome reaction and penetration of the ZP on the exposure of the MSH27Ep were also studied. It was shown that the percentage of the spermatozoa with the MSH27Ep exposed increased followed with their mature status in PTM. In fact, it had a linear correlativity with the rate of the acrosome reaction. After spermatozoa had passed ZPs, almost all of them became the MSH27-positive in immuno-staining compared with only a part of the spermatozoa after the acrosome reaction. In a word, the exposure of MSH27Ep was coincident with attaining the ability to penetrate the plasma membrane of eggs.

Immunolocation of antisperm monoclonal antibody 6B10 and corresponding antigen

An antisperm monoclonal antibody 6B10 was produced by hybridoma technique of the isotype IgG. The monoclonal antibody was purified by means of ammonium sulfate precipitation and protein A-Sepharose C1-4B affinity chromatography. SDS polyacrylamide gel electrophoresis was used to evaluate the purity of the antibody. Evaluation of the sperm acrosomal status was determined by chlortetracycline (CTC) staining. It was found that monoclonal antibody 6B10 can inhibit the sperm acrosome reaction induced by progesterone. The corresponding antigen recognized by monoclonal antibody 6B10 was located on the plasma membrane of the sperm acrosome by indirect immunofluorescent microscopy and immunoelectronmicroscopy. Sperm protein was extracted by 1% Triton X-100. The molecular weight of the antigen is 50 ku, detected by Western blot. The antigen is a key protein in the sperm acrosome reaction and may be the receptor of progesterone on the sperm acrosome. It may either be developed as a candidate contraceptive vaccine or be used as a tool in pest/rodent management.

[Neoplasm-inhibiting effect and sensitivity-promoting effect of indomethacin in vitro]

OBJECTIVE

To explore an anti-tumor effect of indomethacin on human colon adenocarcinoma cell line HCT116, and its mechanism.

METHODS

MTT, agarose gel electrophoresis, TdT and flow cytometry were used to study cell proliferation and apoptosis.

RESULTS

Indomethacin significantly inhibited the proliferation of HCT116 cells and induced apoptosis with a "dose-time" dependent pattern. A synergic effect of inhibiting cancer cells proliferation was observed when combined with 5-Fu.

CONCLUSION

Inhibition of proliferation and induction of apoptosis contribute to the mechanisms for anti-tumor activity of indomethacin.

[Effect of EBV-LMP and EGF autocrine on proliferation of nasopharyngeal carcinoma cell line CNE and their relationship in action]

EBV-LMP gene transfection, radioimmuno-binding assay (RIA) and colorimetric cell viability assay (MTT) were used to investigate the effect and relationship of EBV-LMP and EGF autocrine on the growth and proliferation of well differentiated nasopharyngeal carcinoma cell line (CNE1). Autocrine EGF was detected in the supernant of CNE1 cells and CNE1 cells could grow in serum-free medium, implicating that the cell proliferation-promoting effect of EGF autocrine was present in the CNE1 cell line. Nevertheless the positive signals of LMP gene polymerase chain reaction and LMP Mab immunohistochemical staining in pCMV alpha-LMP DNA transfected cells, confirmed the successful transfection of LMP gene. EGF autocrine amount and the proliferation of CNE1 cells in serum-free medium were more obvious in post-transfected cells than those in untransfected cells. The present study represents the first report on promotion of EGF autocrine in EBV-LMP-transfected cells, thus promoting cell proliferation.

Rat hindlimb muscle blood flow during level and downhill locomotion

During eccentrically biased exercise (e.g., downhill locomotion), whole body oxygen consumption and blood lactate concentrations are lower than during level locomotion. These general systemic measurements indicate that muscle metabolism is lower during downhill exercise. This study was designed to test the hypothesis that hindlimb muscle blood flow is correspondingly lower during downhill vs. level exercise. Muscle blood flow (determined by using radioactive microspheres) was measured in rats after 15 min of treadmill exercise at 15 m/min on the level (L, 0 degrees) or downhill (D, -17 degrees). Blood flow to ankle extensor muscles was either lower (e.g., white gastrocnemius muscle: D, 9 +/- 2; L, 15 +/- 1 ml. min-1. 100 g-1) or not different (e.g., soleus muscle: D, 250 +/- 35; L, 230 +/- 21 ml. min-1. 100 g-1) in downhill vs. level exercise. In contrast, blood flow to ankle flexor muscles was higher (e.g., extensor digitorum longus muscle: D, 53 +/- 5; L, 31 +/- 6 ml. min-1. 100 g-1) during downhill vs. level exercise. When individual extensor and flexor muscle flows were summed, total flow to the leg was lower during downhill exercise (D, 3.24 +/- 0.08; L, 3.47 +/- 0. 05 ml/min). These data indicate that muscle blood flow and metabolism are lower during eccentrically biased exercise but are not uniformly reduced in all active muscles; i.e., flows are equivalent in several ankle extensor muscles and higher in ankle flexor muscles.

[Observation of preventing and treating effect of Salvia miltiorrhiza composita on patients with ischemic coronary heart disease undergoing non-heart surgery]

OBJECTIVE

To observe the preventing and treating effect of Salvia miltiorrhiza composita (SMC) on patients with ischemic coronary heart disease (CHD) undergoing non-heart surgery.

METHODS

The 108 patients were randomly divided into the control group and treatment group. In the treatment group, each patient of 54 were administered SMC intravenously during the operation. ECG, HR, MAP and SpO2 were observed and bleeding quantity was measured perioperatively.

RESULTS

Effective rate of ECG in treatment group was 90.7% (49/54 cases) and the control group was 35.2% (19/54 cases). There was significant difference between the two groups (P < 0.01). HR of the treatment group was no great flutter but control group became faster (P < 0.05). MAP and SpO2 of the two groups were no significant difference perioperatively. There was no significant difference to bleeding quantity between the two groups.

CONCLUSIONS

SMC could effectively improve and protect myocardial ischemia in patients with CHD undergoing non-heart surgery, and no side effect was found.

Effects of aging on cardiac output, regional blood flow, and body composition in Fischer-344 rats

The purpose of this study was to determine the effects of maturation and aging on cardiac output, the distribution of cardiac output, tissue blood flow (determined by using the radioactive-microsphere technique), and body composition in conscious juvenile (2-mo-old), adult (6-mo-old), and aged (24-mo-old) male Fischer-344 rats. Cardiac output was lower in juvenile rats (51 +/- 4 ml/min) than in adult (106 +/- 5 ml/min) or aged (119 +/- 10 ml/min) rats, but cardiac index was not different among groups. The proportion of cardiac output going to most tissues did not change with increasing age. However, the fraction of cardiac output to brain and spinal cord tissue and to skeletal muscle was greater in juvenile rats than that in the two adult groups. In addition, aged rats had a greater percent cardiac output to adipose tissue and a lower percent cardiac output to cutaneous and reproductive tissues than that in juvenile and adult rats. Differences in age also had little effect on mass-specific perfusion rates in most tissues. However, juvenile rats had lower flows to the pancreas, gastrointestinal tract, thyroid and parathyroid glands, and kidneys than did adult rats, and aged rats had lower flows to the white portion of rectus femoris muscle, spleen, thyroid and parathyroid glands, and prostate gland than did adult rats. Body mass of juvenile rats was composed of a lower percent adipose mass and a greater fraction of brain and spinal cord, heart, kidney, liver, and skeletal muscle than that of the adult and aged animals. Relative to the young adult rats, the body mass of aged animals had a greater percent adipose tissue mass and a lower percent skeletal muscle and skin mass. These data demonstrate that maturation and aging have a significant effect on the distribution of cardiac output but relatively little influence on mass-specific tissue perfusion rates in conscious rats. The old-age-related alterations in cardiac output distribution to adipose and cutaneous tissues appear to be associated with the increases in percent body fat and the decreases in the fraction of skin mass, respectively, whereas the decrease in the portion of cardiac output directed to reproductive tissue of aged rats appears to be related to a decrease in mass-specific blood flow to the prostate gland.

Differential expression and biological effects of insulin-like growth factor-binding protein-4 and -5 in vascular smooth muscle cells

Insulin-like growth factor-I (IGF-I) plays an important role in regulating vascular smooth muscle cell (VSMC) proliferation, migration, and apoptosis. The bioactivity of IGF-I is modulated by a group of high affinity, specific binding proteins (IGF-binding proteins; IGFBPs) that are present in the interstitial fluid. Previously, we have reported that porcine VSMCs synthesize and secrete IGF-I and several forms of IGFBPs, including IGFBP-2, IGFBP-4, and IGFBP-5. In this study, we examined the role of autocrine/paracrine secreted IGF-I in controlling the expression of IGFBP-4 and IGFBP-5 as well as the effects of these IGFBPs in modulating the cellular replication response to IGF-I. The concentrations of IGFBP-4 in the conditioned medium increased significantly from <50 ng/ml to 742 +/- 105 ng/ml. This increase was associated with a decrease in the activity of an IGF-I-regulated IGFBP-4 protease. In contrast, the synthesis of IGFBP-5 was inversely correlated with culture density, and its concentration decreased from 792 +/- 91 to 44 +/- 14 ng/ml. IGFBP-5 mRNA in sparse cultures was 3-fold higher compared with those in confluent cultures. This culture density-dependent change in IGFBP-5 mRNA correlated closely with endogenous IGF-I levels. Since treatment of VSMC with exogenous IGF-I increased IGFBP-5 mRNA levels, we neutralized the effect of endogenously secreted IGF-I with an anti-IGF-I antibody to determine if it would alter IGFBP-5 mRNA abundance. This resulted in a 4.4-fold decrease in IGFBP-5 mRNA levels. When added together with IGF-I, exogenous IGFBP-4 inhibited IGF-I-induced DNA synthesis in a concentration-dependent manner. IGFBP-5, on the other hand, potentiated the effect of IGF-I. Therefore, IGFBP-4 and IGFBP-5 appear to be differentially regulated by autocrine/paracrine IGF-I through distinct mechanisms. These two proteins, in turn, play opposing roles in modulating IGF-I action in stimulating VSMC proliferation.

[The preliminary analysis of domestic hydrogel microspheres for endovascular embolization]

OBJECTIVE

To evaluate the embolic effects and biocompatibility of domestic hydrogel microspheres (HMs).

METHOD

22 domestic rabbits were used. 0.03 g/2ml, 0.06 g/2ml domestic Hms of 70 - 150 microm and 2 ml normal saline were injected respectively through catheterization in the right common carotid arteries of rabbits. The changes in neurologic functions, general state and average weight of rabbits were observed, and the histomorphological changes of embolized arteries and surrounding tissues were evaluated by analysis of macroscopy and light microscope.

RESULT

Rabbits' neurologic symptoms (hemiparalysis, convulsion and hypotonia) and death were observed after embolization. Thrombogenesis was present and the entire cross sections of blood vessels could easily be embolized. Neither acute and chronic inflammatory cells nor remarkable general toxic and side effects were shown in rabbits.

CONCLUSION

Domestic HMs can effectively block the vessels, and they have the characteristics of good biocompatibility. The kind of domestic HMs is a promising particulate embolic agent in clinical sets.

The effect of extracellular matrix proteins on porcine smooth muscle cell insulin-like growth factor (IGF) binding protein-5 synthesis and responsiveness to IGF-I

The aim of this study was to determine if cultured porcine vascular smooth muscle cells (pSMCs) that had been maintained on different extracellular matrix proteins had an alteration in their expression of insulin-like growth factor binding protein-5 (IGFBP-5) and their responsiveness to insulin-like growth factor-I (IGF-I). When pSMCs were plated on fibronectin, they synthesized 6.0 +/- 1.2-fold more IGFBP-5 than did cells maintained on laminin and type IV collagen. IGF-I increased IGFBP-5 gene expression 3-fold in the cells plated on fibronectin. The addition of an RGD peptide and echistatin to pSMC cultures that had been plated on fibronectin inhibited IGFBP-5 mRNA expression. The addition of an antibody against alpha2beta1 integrin partially reversed the inhibitory effects of laminin and type IV collagen on IGFBP-5 expression. Cells maintained on fibronectin had a 5.0 +/- 1.1-fold greater DNA synthesis response to IGF-I compared with those maintained on laminin/type IV collagen, and echistatin significantly inhibited the DNA synthesis response of the fibronectin-maintained cells to IGF-I. The anti-alpha2beta1 antibody partially reversed the inhibitory effect of laminin and type IV collagen on IGF-I-stimulated DNA synthesis. The addition of IGFBP-5 to cultures plated on laminin and type IV collagen significantly increased their response to IGF-I. Atherosclerotic plaques from pig aorta contained abundant fibronectin and had increased IGFBP-5 mRNA (4.5 +/- 1.5-fold) compared with tissue from the normal vessel wall that had a low fibronectin content. These results indicate that fibronectin, laminin, and type IV collagen have major effects on IGFBP-5 expression and on IGF-I-stimulated pSMC responses and that these effects are mediated by their respective integrins.

Insulin-like growth factor-binding protein-5 is cleaved by physiological concentrations of thrombin

Insulin-like growth factor (IGF)-binding protein-5 (IGFBP-5) is cleaved by a serine protease that is secreted by fibroblasts and porcine smooth muscle cells (pSMC) in culture. To investigate whether other serine proteases could cleave this substrate at physiologically relevant concentrations, we determined the proteolytic effects of thrombin on IGFBP-5. Human alpha-thrombin (0.0008 NIH U/ml) cleaved IGFBP-5 into 24-, 23-, and 20-kDa non-IGF-I-binding fragments. Cleavage occurred at a physiologically relevant thrombin concentration. The effect was specific for IGFBP-5, as other forms of IGFBPs, e.g. IGFBP-1, IGFBP-2, and IGFBP-4 were not cleaved by thrombin. Although IGFBP-3 was cleaved by thrombin, this effect required a 50-fold greater thrombin concentration. [35S]Methionine labeling followed by immunoprecipitation confirmed that IGFBP-5 that was constitutively synthesized by pSMC cultures was also degraded by thrombin into 24-, 23-, and 20-kDa fragments. The binding of IGF-I to IGFBP-5 partially inhibited IGFBP-5 degradation by thrombin, and an IGF analog that does not bind to IGFBP-5 had no effect. Thrombin did not account for the serine protease activity that had been shown previously to be present in pSMC-conditioned medium. This was proven by showing that 1) no immunoreactive thrombin could be detected in the pSMC-conditioned medium; 2) the IGFBP-5 fragments that were generated by thrombin showed three cleavage sites (Arg192-Ala193, Arg156-Ile157, and Lys120-His121), whereas the serine protease in conditioned medium cleaves IGFBP-5 at a different site; and 3) hirudin had no effect on IGFBP-5 cleavage by the protease in pSMC medium; however, it inhibited IGFBP-5 degradation by thrombin. To determine the physiological significance of IGFBP-5 cleavage, the effect of an IGFBP-5 mutant that is resistant to cleavage by the pSMC protease and has been shown to inhibit IGF-I actions in pSMC was determined. This mutant inhibited IGF-I-stimulated DNA synthesis, but if thrombin was added simultaneously, IGF-I was fully active. In summary, physiological concentrations of thrombin degrade IGFBP-5. Degradation can be blocked by hirudin and is partially inhibited by IGF-I binding. Generation of active thrombin in vessel walls may be a physiologically relevant mechanism for controlling IGF-I bioactivity.

Osteogenic protein-1 regulates insulin-like growth factor-I (IGF-I), IGF-II, and IGF-binding protein-5 (IGFBP-5) gene expression in fetal rat calvaria cells by different mechanisms

Osteogenic protein-1 (OP-1 or BMP-7) stimulates new bone formation in vivo and induces cell proliferation and differentiation of osteoblasts in vitro. Previous studies from our laboratory revealed that OP-1 led to a two- to threefold increase in steady-state insulin-like growth factor-I (IGF-I) and IGF-II mRNA levels and a fivefold decrease in IGF-binding protein-5 (IGFBP-5) mRNA levels in primary cultures of fetal rat calvaria (FRC) cells. In the present study, we determined whether the effects of OP-1 were at the transcriptional or posttranscriptional level. OP-1 increased the half-life of the IGF-I mRNA from 6 to 17 h without changing the level of IGF-I nuclear pre-mRNA. In transiently transfected FRC cells, the luciferase activity driven by the -1122/+362 or the -133/+362 IGF-I exon 1 promoter fragment was not changed by OP-1. Similar results were observed using the -1500/+44 or -362/+44 IGF-I exon 2 promoter constructs. Effects of OP-1 on IGF-I mRNA were independent of cell division, as they remained elevated in the presence of hydroxyurea. Cycloheximide inhibited moderately the OP-1-induced increase in IGF-I mRNA, suggesting partial dependency on protein synthesis. On the other hand, the IGF-II nuclear pre-mRNA levels were increased by OP-1 but the half-life of the mature IGF-II mRNA was not affected. Effects of OP-1 on IGF-II mRNA were also independent of cell division, but were dependent on protein synthesis. OP-1 caused a 43-50% reduction in the level of IGFBP-5 nuclear pre-mRNA transcripts and a 40% decrease in the IGFBP-5 promoter activity in FRC cells transfected with the -1278/+1 IGFBP-5 promoter fragment. The half-life of the mature IGFBP-5 mRNA was not affected by OP-1. Hydroxyurea did not prevent the OP-1-induced reduction in IGFBP-5 mRNA. The level of IGFBP-5 mRNA was barely detectable in the presence of cycloheximide, and further suppressive effect of OP-1 on IGFBP-5 mRNA could not be determined. In conclusion, OP-1 regulates IGF-I gene expression at the posttranscriptional level, but regulates IGF-II and IGFBP-5 gene expression at the transcriptional level.

Generation of carbohydrate-deficient transferrin by enzymatic deglycosylation of human transferrin

Carbohydrate-deficient transferrin (CDT) molecules are transferrin isoforms that lack one or both of the carbohydrate groups attached to a normal human transferrin molecule. CDT has been reported to be a sensitive and specific marker for diagnosing alcoholism. This report demonstrates the in vitro generation of CDT molecules that can potentially be used as the standard in measuring CDT concentrations. This was achieved by deglycosylation of human transferrin with the enzyme Endo-beta-N-acetylglucosaminidase F2 (Endo-F2). The enzyme was immobilized on sepharose beads, which were packed into a column. The immobilization of the enzyme not only eliminated the Endo-F2 contamination of CDT, but also rendered the enzyme suitable for repetitive use. In this manner, it was possible to obtain at least 200 mg of CDT over a period of more than 3 mo, without any noticeable decrease of enzyme activity, using only 3.0 micrograms of enzyme. This proved to be an efficient method for generating CDT.

Nutritional and developmental regulation of insulin-like growth factors in fish

The insulin-like growth factors (IGF) are evolutionarily ancient growth factors present in all vertebrates. The central importance of IGF for normal development and growth has been illustrated by the severe growth-retarded phenotype exhibited by IGF-I, IGF-II or IGF-I receptor "knockout" mice. Although we know much about the gross effects of IGF on the overall size of the fetus and the clinical manifestations that result from fetal and neonatal deficiency of IGF (i.e., severe growth retardation leads to dwarfism), very little is known about the in vivo actions of IGF during embryogenesis at the cellular and molecular levels. Most research on the developmental role of IGF has relied on rodent models, and attempts to elucidate the molecular and cellular basis of IGF actions have been hampered by the inaccessibility of the mammalian fetus enclosed in the uterus. During the past decade, there has been growing support for the concept that the IGF have been highly conserved in all vertebrates. Both IGF-I and IGF-II are present in fish, and their structures are highly conserved. Human and fish IGF-I are equally potent in mammalian and fish bioassay systems. Insulin-like growth factor mRNA is found in all life stages of fish, ranging from unfertilized egg to adult. The temporal and spatial expression patterns of fish IGF-I seem to be similar to those in mammals. Nutritional status and growth hormone both have a profound effect on IGF-I expression in fish, as they do in mammals. These features suggest that the IGF system is highly conserved between teleost fish and mammals. Because fish embryos develop externally, they provide excellent animal models for understanding the regulatory roles of IGF, IGF receptor and IGF-binding proteins in vertebrate embryonic development. Current research on the developmental and nutritional roles of IGF in fish will undoubtedly contribute to knowledge of the basic physiology of vertebrates in general.

Retinoic acid inhibits cell growth in HPV negative cervical carcinoma cells by induction of insulin-like growth factor binding protein-5 (IGFBP-5) secretion

Retinoids have been demonstrated to inhibit epithelial cell growth and differentiation. We examined the anti-proliferative effects of retinoic acid (RA) in an HPV positive and negative cervical carcinoma cell line. Our findings indicate that HPV-negative C33A cervical carcinoma cells are more sensitive to the growth inhibitory activity of retinoic acid (RA) than are HPV-positive CaSki cervical carcinoma cells. However, conditioned medium from RA-treated C33A cells displayed strong growth inhibitory activity in both C33A and CaSki cells. Since RA has been shown to modulate the expression of insulin-like growth factor binding proteins (IGFBPs) in many cells, we examined RA regulated expression of IGFBPs in medium isolated from RA treated C33A cells. IGFBP-5 was detectable in medium from C33A cells exposed to RA, and addition of purified exogenous IGFBP-5 resulted in growth inhibition of C33A cells. These results indicate that RA exerts it's anti-neoplastic effect in HPV negative cervical carcinoma cells via the overproduction of IGFBP-5.

Changes in skeletal muscle biochemistry and histology relative to fiber type in rats with heart failure

One of the primary consequences of left ventricular dysfunction (LVD) after myocardial infarction is a decrement in exercise capacity. Several factors have been hypothesized to account for this decrement, including alterations in skeletal muscle metabolism and aerobic capacity. The purpose of this study was to determine whether LVD-induced alterations in skeletal muscle enzyme activities, fiber composition, and fiber size are 1) generalized in muscles or specific to muscles composed primarily of a given fiber type and 2) related to the severity of the LVD. Female Wistar rats were divided into three groups: sham-operated controls (n = 13) and rats with moderate (n = 10) and severe (n = 7) LVD. LVD was surgically induced by ligating the left main coronary artery and resulted in elevations (P < 0.05) in left ventricular end-diastolic pressure (sham, 5 +/- 1 mmHg; moderate LVD, 11 +/- 1 mmHg; severe LVD, 25 +/- 1 mmHg). Moderate LVD decreased the activities of phosphofructokinase (PFK) and citrate synthase in one muscle composed of type IIB fibers but did not modify fiber composition or size of any muscle studied. However, severe LVD diminished the activity of enzymes involved in terminal and beta-oxidation in muscles composed primarily of type I fibers, type IIA fibers, and type IIB fibers. In addition, severe LVD induced a reduction in the activity of PFK in type IIB muscle, a 10% reduction in the percentage of type IID/X fibers, and a corresponding increase in the portion of type IIB fibers. Atrophy of type I fibers, type IIA fibers, and/or type IIB fibers occurred in soleus and plantaris muscles of rats with severe LVD. These data indicate that rats with severe LVD after myocardial infarction exhibit 1) decrements in mitochondrial enzyme activities independent of muscle fiber composition, 2) a reduction in PFK activity in type IIB muscle, 3) transformation of type IID/X to type IIB fibers, and 4) atrophy of type I, IIA, and IIB fibers.

[Elimination of cholesterol in human endothelial cells]

OBJECTIVE

To investigate what role the endothelial cell interfacing with blood components to play in cholesterol metabolism.

METHODS

Isotopelabeling technique, Gas Chromatography/Mass Spectrometry and Western blotting were used to measure the presence of 27-oxygenated cholesterol in medium and the presence of sterol 27-hydroxylase in endothelium.

RESULTS

When human endothelial cells were cultured in a medium containing fetal calf serum, there was a significant accumulation of 27-hydroxycholesterol and 3 beta-hydroxy-5-cholesteneic acid, products of cholesterol metabolism, in the medium. The rate of formation of these products almost increased linearly with time of cultivation. After addition of 100 micrograms of extraneous cholesterol to the medium, the accumulation of 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid increased significantly. Addition of more cholesterol did not further increase the formation of 27-hydroxy-cholesterol and caused a decrease in the formation of 3 beta-hydroxy-5 cholesteneic acid. The presence of sterol-27-hydroxylase in the endothelium was demonstrated by Western blotting.

CONCLUSION

Cultured human endothelium from umbilical veins are able to convert exogenous cholesterol into 27-hydroxy-cholesterol and 3 beta-hydroxy-5-cholesteneic acid. Furthermore, the cells are able to transport these products from the cells into the medium.

A T-cell model for the biological role of selenium-dependent glutathione peroxidase

The cytosolic form of selenium-dependent glutathione peroxidase detoxifies both hydrogen and lipid peroxides and therefore represents a major component of the cellular anti-oxidant defenses. In order to study the biological role of this enzyme, we generated an expression construct in a retroviral vector, which when introduced into immortalized human T-cells, resulted in significant increases in the activity of this important enzyme. This effect is stable over extended maintenance in culture. The anti-oxidant defenses in these same cells are also shown to be attenuated by chemically reducing cellular glutathione levels. Collectively, the ability to both increase and decrease the anti-oxidant defenses in human T cells results in a useful model system for the study of oxidative stress and signaling in this cell type.

Functional properties of conditioned skeletal muscle: implications for muscle-powered cardiac assist

Latissimus dorsi (LD) muscles of six canines were studied to assess changes induced by electrical conditioning and to quantify the capacity of these muscles to perform hemodynamic work. Muscles were conditioned using burst stimuli delivered over an 8-wk period. Contralateral LD were used as control. Muscles were tested in situ to simulate anticipated linear-pull cardiac assist conditions. This training process reduced muscle mass and cross-sectional area by 16 and 17%, respectively. Muscle phenotype shifted to a predominantly "slow" form by coordinate reduction of myosin heavy chain (MHC) 2A expression and increased expression of the MHC beta/slow form. Force generation was reduced by 54%, and contractile duration increased 13%. Fatigue resistance was markedly enhanced, and chronic stroke work increased from 0.19 to 0.72 mJ/g. The highest steady-state power output (2.06 mW/g) was obtained from one muscle fully converted to a slow phenotype. These data suggest that single LD trained via conventional techniques can provide energy sufficient for partial cardiac assistance but cannot sustain work levels needed to achieve total circulatory support.

Candidacidal activity of human salivary histatin recombinant variants produced by site-directed mutagenesis

Histatin 5 (Hst5) is a 24-amino acid (aa) member of the Hst family that is found in human salivary secretions and exhibits candidacidal activity. Hst5 contains a 13-aa region that alone is capable of killing fungal pathogens and is referred to as the functional domain. To investigate the role of specific aa located within the functional domain, the pRSET bacterial expression system was used to produce recombinant Hst5 (re-Hst5) and several re-variants that were generated by site-directed mutagenesis. The vector pRSETC expresses genes of interest as fusion proteins attached to the carboxy end of an N-terminal His6 tag that binds to nickel (Ni2+). The re-variants were generated using the polymerase chain reaction (PCR) and had Gly substituted for either the His, Glu or Lys/Arg within the functional domain. PCR products that encoded either the wild-type or variant forms of re-Hst5 were inserted into pRSETC and produced as fusion proteins which were affinity purified from cell lysates by Ni(2+)-Sepharose chromatography. Fusion proteins were digested with CNBr and re-Hsts were purified by reversed-phase high performance liquid chromatography (RP-HPLC). Re-Hsts were tested in bioassays to measure the ability to kill both Candida albicans (C. albicans) blastoconidia and spheroplasts which were generated by removal of the cell wall. In both assays, re-Hst5 displayed dose-dependent candidacidal activity that was nearly identical to that of native Hst5 purified from human salivary secretions. Re-Hst5 variants with either Glu or Lys/Arg substitutions demonstrated significantly lower candidacidal activity in both assays, while the variant with His mutated showed essentially no activity at physiological concentrations. These results indicate that acidic and basic aa within the functional domain contribute to candidacidal activity and that the His are essential for candidacidal activity. Additionally, since C. albicans spheroplasts were also susceptible to Hsts, the cell wall is not an essential component in the Hst mechanism of candidacidal action.

Signal transduction pathways in guinea pig sperm

Trifluoperazine (TFP), the antagonist of calmodulin (CaM), significantly stimulated the capacitation and acrosome reaction of guinea pig spermatozoa at the concentration of 10-100 mumol/L, independent of the external Ca2+. Forskolin, dbcAMP and caffeine evidently promoted the occurrence of acrosome reaction of spermatozoa at early capacitation stage (5 h) in nonsynchronous system but not in synchronous system. If the spermatozoa were capacitated for 15 h in synchronous system, the above three drugs significantly stimulated acrosome reaction in a Ca(2+)-independent manner. Protein kinase C activators, i.e. phorbol 12-myristate 13-acetate (PMA) and phorbol 12,13-dibutyrate (PDB) did not influence the occurrence of acrosome reaction of spermatozoa at early capacitation stage, but significantly increased the acrosome reaction rate in capacitated spermatozoa in a Ca(2+)-independent manner. In contrast, PKC inhibitor staurosporine significantly inhibited the occurrence of acrosome reaction.

Insulin-like growth factor-I (IGF-I) regulates IGF-binding protein-5 synthesis through transcriptional activation of the gene in aortic smooth muscle cells

Previous studies have shown that porcine aortic smooth muscle cells (SMCs) secrete two insulin-like growth factor-binding proteins (IGFBP), IGFBP-2 and -4, and that these IGFBPs modulate IGF-I-stimulated SMC proliferation and migration. In this study we demonstrate that porcine SMCs express IGFBP-5 mRNA and synthesize and secrete the protein. In this cell type, the biosynthesis of IGFBP-5 is up-regulated by IGF-I. This increase in IGFBP-5 synthesis is accompanied by an increase in the steady-state mRNA levels. The induction of IGFBP-5 mRNA by IGF-I is time- and dose-dependent and requires de novo protein synthesis. IGF-II and insulin also increase IGFBP-5 mRNA levels at high doses. An IGF-I analog with normal affinity for the IGF-I receptor but reduced affinity for IGFBPs evokes a similar increase. Another analog that binds to IGFBPs but not to the receptor has no effect, indicating that this effect of IGF-I is mediated through the IGF-I receptor. The IGF-I-induced IGFBP-5 gene expression is cell type-specific because IGF-I had no such effect in other cell types examined. Nuclear run-on assays revealed that IGF-I increased transcription rate of the IGFBP-5 gene, while IGF-I did not change the IGFBP-5 mRNA stability. Furthermore, the IGFBP-5 promoter was 3.5-fold more active in directing expression of the luciferase reporter gene in IGF-I-treated aortic SMCs as compared to control cells, whereas the luciferase activity remained the same in control- and IGF-I-treated fibroblasts. These results suggest that IGF-I up-regulates IGFBP-5 synthesis by transcriptionally activating the IGFBP-5 gene in aortic SMCs.

Composition and size of type I, IIA, IID/X, and IIB fibers and citrate synthase activity of rat muscle

A population of muscle fibers containing a myosin heavy-chain isoform IId (or 2x) has recently been identified in rat muscle. The purpose of this study was to histochemically determine the relative population and size of muscle fibers composed of type IID/X fibers as well as type I, IIA, and IIB fibers to estimate the absolute mass of the different types of fibers in rat muscle. In addition, muscle citrate synthase activity was measured to determine the relationship between fiber composition and muscle oxidative capacity. Seventy-six muscles or muscle parts from the face, neck, shoulder, arm, trunk, hip, thigh, and leg of three adult (4.5-5 mo of age) male Sprague-Dawley rats were removed, weighed, and frozen for histochemical and biochemical analyses. The data demonstrated that type IIB fibers make up 71% of the total muscle mass, type IID/X fibers 18%, type IIA fibers 5%, and type I fibers 6%. The mean cross-sectional area across all muscles was 5,078 +/- 175 microns 2 for type IIB fibers, 3,078 +/- 105 microns2 for type IID/X fibers, 2,045 +/- 80 microns2 for type IIA fibers, and 1,898 +/- 90 microns2 for type I fibers. Citrate synthase activity, an indicator of muscle mitochondrial content, was most closely related to the population of type IIA fibers and was in the rank order of type IIA > I > IID/X > IIB. NADH-tetrazolium reductase staining intensity also confirmed this order. These data demonstrate that type IID/X fibers make up a significant portion of the adult rat muscle mass and are intermediate to type IIA and IIB fibers in regard to fiber size and oxidative potential.

Interleukin-12 synergizes with interleukin-2 to generate lymphokine-activated killer activity in peripheral blood mononuclear cells cultured in ovarian cancer ascitic fluid

OBJECTIVES

The ascites-associated lymphocytes in ovarian cancer have altered immunologic function, and cell-free ascitic fluid has immunomodulating properties. We determined (1) whether interleukin (IL)-2 could induce lymphokine-activated killer (LAK) activity in normal peripheral blood mononuclear cells (PBMC) cultured in ovarian cancer ascitic fluid, and (2) whether IL-12 could synergize with IL-2 to generate LAK activity in normal PBMC cultured in ascitic fluid.

METHODS

Normal PBMC were cultured in control medium and in media consisting of 50% ascitic fluid (ascitic medium), with and without IL-2 and IL-12. Cell activation to assess LAK activity (cell lysis) was determined in a 51Cr-release assay with the tumor cell lines FMEX and SKOV3 as target cells. To determine a possible mechanism for any synergistic effect, the expression of perforin, a pore-forming protein, was determined by Northern blot analysis.

RESULTS

Interleukin-2 alone could not induce LAK activity in normal PBMC cultured in 50% ascitic fluid for up to 3 days. Interleukin-12 did mediate some or minimal LAK activity after 1, 2, or 3 days of incubation in control medium or in 50% ascitic fluid. When IL-2 and IL-12 were used in combination, PBMC cultured for 3 days in 50% ascitic fluid had remarkably high lytic activity against FMEX and SKOV3 tumor cells. In some experiments, this cytotoxicity was greater than that in PBMC cultured in control medium with IL-2 and IL-12. Lower concentrations of IL-12 (1 U/mL) with IL-2 (100 U/mL) were as effective as, and often more effective than, higher doses of IL-12 with IL-2. Very low-dose IL-12 (0.01-0.03 U/mL) in combination with IL-2 also induced a range of cytotoxicities. Only the combination of IL-2 and IL-12 up-regulated expression of perforin mRNA in ascitic medium.

CONCLUSIONS

The cytotoxicity responses of PBMC cultured in ascitic fluid in the presence of IL-2 and IL-12 are complex. Low-dose IL-2 and IL-12 can overcome the inhibitory property of ascitic fluid on LAK generation and can restore and enhance cytotoxic activity, possibly by reconstituting the expression of perforin. These findings may have therapeutic potential.

Transcription factor AP-2 regulates human insulin-like growth factor binding protein-5 gene expression

Insulin-like growth factor binding protein-5 (IG-FBP-5) is an important modulator of IGF actions. IG-FBP-5 mRNA is abundant in human fibroblasts and is regulated by cAMP. To understand the molecular mechanism underlying this cell type-specific expression and regulation, we isolated the 5'-flanking region of the human IGFBP-5 gene and fused it to a promoter-less reporter plasmid encoding luciferase. Transient transfection of the construct into fibroblasts displayed both constitutive and cAMP-induced promoter activity in an orientation-specific manner. Sequence analysis revealed the existence of distal and proximal consensus AP-2 recognition sites located 5' from the TATA box. Both sequences bound specifically to human AP-2 in vitro by gel shift mobility assay. The possible role of AP-2 was examined by cotransfection of AP-2-deficient HepG2 cells with the IGFBP-5 promoter construct and a human AP-2 expression construct. Cotransfection with AP-2 significantly elevated IGFBP-5 promoter activity. This trans-activation was IGFBP-5 promoter and AP-2 specific. In AP-2 abundant fibroblasts, expression of AP-2B, a dominant-negative inhibitor of AP-2, suppressed IGFBP-5 promoter activity. In HepG2 cells, AP-2B alone had no significant effect, but the AP-2-induced activation of promoter activity was inhibited by AP-2B in a dose-dependent manner. The relative functional importance of the putative AP-2 binding sites was examined using a number of deletion mutants and point mutations. When the first two distal CCCCACCC-like putative AP-2 sites were deleted or mutated, there was no change in AP-2-induced trans-activation. Deletion or mutation of the proximal GCCNNNGGC-like sequences, however, abolished the AP-2-induced activation. These results suggest that AP-2 regulates the IGFBP-5 gene expression through the proximal GCCNNNGGC-like sequences. This AP-2-mediated trans-activation contributes at least in part to the constitutively high expression of IGFBP-5 in fibroblasts and to the cAMP responsiveness of this gene.

Novel nonseparation sandwich-type electrochemical enzyme immunoassay system for detecting marker proteins in undiluted blood

A novel nonseparation electrochemical enzyme immunoassay (NEEIA) for detecting marker proteins in undiluted blood is described. The approach is based on preferential electrochemical measurement of surface-bound enzyme-labeled reporter antibody (E-Ab), relative to an excess of this reagent in the sample solution. NEEIAs are carried out on microporous membranes coated with a thin, circular area of gold. The gold serves simultaneously as a working electrode and solid phase for immobilized capture anti-protein antibodies. In the assay, analyte protein is incubated concurrently with the Ab-coated gold surface and excess E-Ab conjugate. Detection of bound E-Ab is achieved by introducing the substrate for the enzyme through the back side of the membrane. The product of bound E-Ab is detected immediately by oxidation or reduction at the gold electrode, and the resulting current is proportional to the concentration of protein in the sample. The feasibility of the NEEIA approach is demonstrated via the detection of prostate-specific antigen in undiluted plasma samples (n = 64), with alkaline phosphatase as the label. Use of multiple gold films deposited on the same porous membrane to perform simultaneous NEEIAs is also described.

Novel nonseparation sandwich-type electrochemical enzyme immunoassay system for detecting marker proteins in undiluted blood

A novel nonseparation electrochemical enzyme immunoassay (NEEIA) for detecting marker proteins in undiluted blood is described. The approach is based on preferential electrochemical measurement of surface-bound enzyme-labeled reporter antibody (E-Ab), relative to an excess of this reagent in the sample solution. NEEIAs are carried out on microporous membranes coated with a thin, circular area of gold. The gold serves simultaneously as a working electrode and solid phase for immobilized capture anti-protein antibodies. In the assay, analyte protein is incubated concurrently with the Ab-coated gold surface and excess E-Ab conjugate. Detection of bound E-Ab is achieved by introducing the substrate for the enzyme through the back side of the membrane. The product of bound E-Ab is detected immediately by oxidation or reduction at the gold electrode, and the resulting current is proportional to the concentration of protein in the sample. The feasibility of the NEEIA approach is demonstrated via the detection of prostate-specific antigen in undiluted plasma samples (n = 64), with alkaline phosphatase as the label. Use of multiple gold films deposited on the same porous membrane to perform simultaneous NEEIAs is also described.

Augmentation of carcinoembryonic antigen release from intact, viable tumor cells by a factor in human serum

BACKGROUND

Measurement of carcinoembryonic antigen (CEA) levels in human serum is frequently used to detect tumor recurrence in patients with resected primary colorectal cancers. These levels are highly variable from patient to patient, and the mechanism that determines these levels is still poorly understood.

METHODS

Using a 6-h in vitro CEA-release assay, we determined that a factor in human and fetal bovine sera significantly augments the release of CEA from the tumor cell surface into cell culture supernatants.

RESULTS

As little as 1% serum admixed with tumor cells results in CEA release up to 200% greater than that of serum-free controls. It is not inhibited by 1,10-phenanthroline or heat inactivation (of serum) but is calcium dependent. The electrophoretic mobility and membrane linkage of CEA released by serum appear to be identical to those of CEA released by bacterial phospholipase C. Because bacterial phospholipase C is known specifically to cleave the phosphoinositol (PI) glycan moiety that anchors CEA to the tumor cell surface, a mechanism of action for serum cleaving this anchor is suggested.

CONCLUSIONS

The large range of CEA levels observed in patients with colorectal cancers may be related to differential sensitivity of the CEA membrane anchor to the CEA-releasing factor in serum.

Role of extracellular adenosine triphosphate in the cytotoxic T-lymphocyte-mediated lysis of antigen presenting cells

The lysis of antigen presenting cells (APCs) by cytotoxic T lymphocytes (CTLs) may be one mechanism whereby an immune response is downregulated by Staphylococcus superantigens. Disappearance of monocytes/macrophages from staphylococcal enterotoxin A (SEA)-activated peripheral blood mononuclear cell (PBMC) cultures, but not from control PBMC cultures was seen by flow cytometry. Recently, adenosine triphosphate (ATP) has been described as an effector molecule in CTL-mediated lysis of some murine tumor target cells. We have also shown that ATP caused the lysis of human macrophages, and that treatment of cells with interferon gamma (IFN gamma) rendered macrophages significantly more sensitive to ATP than untreated cells. To show that this purine nucleotide may play a role in modulating the immune system, we generated human CTLs that were stimulated with SEA, and used them as effector cells against SEA-pulsed autologous macrophages. CTLs were found to specifically lyse SEA-pulsed macrophages, while control, unpulsed, macrophages were unaffected. The addition of hexokinase, an enzyme that hydrolyzes ATP, significantly abrogated the killing of SEA-pulsed cells during the assay. In examining the mechanism of cytotoxicity, electron microscopy showed that macrophages incubated with both ATP and CTLs underwent necrosis, rather than apoptosis. From these results, it is suggested that ATP is released from CTLs during antigen presentation, and that IFN gamma-activated macrophages, which are inherently more sensitive to this mediator, are readily lysed and therefore removed from circulation, thus downregulating an immune response.

Expression of insulin-like growth factor I in normally and abnormally developing coho salmon (Oncorhynchus kisutch)

Changes in levels of insulin-like growth factor-I (IGF-I) messenger RNA (mRNA) in tissues of normally and abnormally growing (stunted) juvenile coho salmon in seawater were studied. Profiles of hepatic IGF-I mRNA levels were compared with changes in growth and plasma concentrations of GH and insulin. In normally growing fish, IGF-I mRNA levels, as measured by solution hybridization-RNase protection assay, showed that hepatic IGF-I mRNA levels of yearling salmon were highest in May and June. Increased hepatic IGF-I mRNA levels followed increases in both plasma GH and insulin. Levels of hepatic IGF-I mRNA decreased in July, after a sharp decline in plasma GH in June, and remained low until the following spring. The growth rate for normal fish also decreased during fall and winter. After increases in plasma GH and insulin, which peaked in late February, hepatic IGF-I mRNA levels increased rapidly and reached a second peak in April. Increases in plasma GH and hepatic IGF-I mRNA observed in the second year were smaller and occurred earlier than in the first spring in seawater. Growth retardation (stunting) resulted from the premature transfer of cultured fish to seawater. Compared with normally growing fish, these stunted salmon had significantly higher levels of plasma GH but lower levels of plasma insulin. Hepatic IGF-I mRNA levels in stunted salmon were significantly lower, despite elevated plasma GH levels. These results indicate that hepatic levels of IGF-I mRNA in juvenile coho salmon increase in springtime, after an increase in plasma GH and insulin. These seasonal increases in GH and IGF-I precede the rapid growth period coinciding with the springtime increases in temperature and photoperiod and may therefore be associated with these environmental cues. The elevated plasma GH and reduced hepatic IGF-I mRNA levels observed in growth-retarded salmon suggested that stunted salmon may be GH resistant. Hepatic GH resistance and diminished IGF-I production may be the central endocrine defects leading to growth retardation in stunted salmon.