Insulin regulates transcription of the CCAAT/enhancer binding protein (C/EBP) alpha, beta, and delta genes in fully-differentiated 3T3-L1 adipocytes

The effect of insulin on expression of CCAAT/enhancer binding protein (C/EBP) alpha, beta, and delta was investigated in fully-differentiated 3T3-L1 adipocytes. Treatment of adipocytes with insulin stimulated rapid dephosphorylation of C/EBP alpha, and repressed the expression of C/EBP alpha within 2-4 h, with > 90% suppression occurring at 24 h. While insulin induced expression of C/EBP beta and C/EBP delta within 1 h and caused a > 20-fold increase by 4 h, expression returned to nearly pretreatment levels by 24 h. The insulin concentration dependence of these effects was consistent with involvement of the insulin receptor. Gel shift analysis revealed that 6 h of insulin treatment decreased the binding of nuclear C/EBP alpha while increasing binding of nuclear C/EBP beta and C/EBP delta. The reciprocal effects of insulin on the steady-state levels of C/EBP transcription factors can be accounted for kinetically and quantitatively by changes in their mRNA levels, which can be accounted for by effects on gene transcription. The effects of insulin on adipocyte gene transcription (e.g. GLUT4) may be mediated, at least in part, by down-regulation of C/EBP alpha and/or its dephosphorylation.

Deletion of lysine 121 creates a temperature-sensitive alteration in insulin binding by the insulin receptor

Recently we reported the deletion of Lys-121 in one allele of the insulin receptor gene from a child with severe insulin resistance. In the present work, this mutant receptor (M121) was shown to have an abnormal sensitivity to temperature and an alteration in "negative cooperativity." In contrast to the wild-type receptor (HIRC), insulin binding by the M121 receptor was rapidly and irreversibly lost at temperatures above 30 degrees C with the phosphorylated form of the receptor being more temperature-sensitive than the nonphosphorylated form. Although insulin binding activity was lost, Western analysis and other studies showed that the mutant receptor remained intact. Measurements of 125I-insulin dissociation at 21 degrees C in the presence of native insulin (an estimate of negative cooperativity) demonstrated a difference between the mutant and wild-type receptor. Insulin dissociation from the mutant receptor was not as pronounced as that found with the wild-type receptor. Thus, an abnormality in insulin binding by the mutation was evident at lower "permissive" temperatures. The results of these and other studies argue that Lys-121 occupies an important position for the regulation of insulin receptor conformation. This regulation apparently influences negative cooperative interactions with insulin and modulates signal transduction.

Association between coronary heart disease and the apolipoprotein A-I/C-III/A-IV complex in a Japanese population

Several studies have reported that a variant allele (S2) of the apolipoprotein (apo) A-I/C-III/A-IV complex is associated with hyperlipoproteinemia in some populations and that the frequency of this allele is two- to fivefold higher in patients with premature coronary heart disease (CHD) than in healthy controls. In the present study in a Japanese population, we were unable to confirm the association of the S2 allele with either coronary heart disease or elevated serum apo C-III levels, as has been previously reported in Caucasians. No genotype difference was observed among the severity of coronary heart disease, as determined by the number of involved vessels (one, two and three vessel disease), compared to controls. In addition, the frequency of the S2 allele among Japanese, in both CHD (0.328) and controls (0.369), was quite different from that in many other populations.

In vitro drug testing of ovarian cancer using the human tumor colony-forming assay: comparison of in vitro response and clinical outcome

The purpose of this study was to assess the prognostic value of in vitro drug chemosensitivity testing using the Hamburger-Salmon human tumor colony-forming assay (HTCA) in fresh tumor samples obtained from newly diagnosed patients with stage II-IV ovarian cancer undergoing maximum cytoreductive surgery and prior to platinum-based chemotherapy. The HTCA was performed on fresh ovarian cancers obtained from 93 patients at their initial exploratory laparotomy to evaluate in vitro sensitivity to cisplatin, carboplatin, and cyclophosphamide following a 1-hr drug exposure. Prospective clinical follow-up was performed on all patients with the primary study endpoints being pathologically proven complete response at second-look surgery and disease-free and overall survival durations. In vitro drug sensitivity was strongly dose-dependent. At a concentration of 5 micrograms/ml only 23% of tumor samples were sensitive (as defined by a > or = 50% decrease in tumor colony-forming units compared to controls) to cisplatin; 13% of tumors were sensitive to carboplatin at a concentration of 50 micrograms/ml and 11% to 4-OH-cyclophosphamide at a concentration of 1 microgram/ml. At doses which were 10 times the previously stated concentrations, the sensitivity rates to cisplatin, carboplatin, and 4-OH-cyclophosphamide increased to 72, 63, and 53%, respectively. Subjects were categorized as having drug-sensitive disease if HTCA results showed in vitro drug sensitivity to at least one of the agents used in their primary chemotherapy. Multivariate analysis failed to show any advantage in clinical response rate, progression-free interval, or survival duration for patients with drug-sensitive disease compared to drug-resistant disease; however, there was evidence of a trend toward an enhanced pathologically proven complete response rate in patients who had chemosensitive tumors in vitro. Second-look surgery was performed in 28 of 55 patients with optimal surgical resections and no clinical evidence of disease at the completion of their primary chemotherapy. Fifty percent (5/10) of patients with drug-sensitive disease achieved a pathologic complete response, while only 3/18 (17%) patients with drug-resistant tumors had a documented pathologic complete response (P = 0.13). As reported in other ovarian cancer studies, patient characteristics which were found to be significantly associated with survival were stage of disease (II-III vs IV), optimal primary surgical resection (i.e., < 1 cm2 residual tumor) vs suboptimal resection, clinical measurability of disease at initiation of chemotherapy, and response to primary chemotherapy. In conclusion, in vitro drug sensitivity, as measured by the HTCA, does not appear to be an independent prognostic factor for survival in patients with stage II-IV epithelial ovarian cancer who undergo standard treatment with tumor debulking surgery and primary platinum-based chemotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)

gamma-Glutamyl transpeptidase is increased by oxidative stress in rat alveolar L2 epithelial cells

The tripeptide glutathione (GSH) is used by cells to detoxify hydroperoxides, produced during oxidative stress, and is consumed in the process. Previous studies have indicated that cells can be protected against oxidative stress by extracellular GSH through its degradation catalyzed by the exoenzyme gamma-glutamyl transpeptidase (gamma GT) and its de novo synthesis within the cytosol. We hypothesized that gamma GT would be increased as part of the adaptation of cells to oxidative stress. We examined whether oxidative stress could increase gamma GT activity, protein, and mRNA in a lung epithelial cell line (L2). Cultures were subjected to H2O2-mediated toxicity by 15 min of exposure to the redox cycling quinone, menadione. Menadione (50 microM) caused an initial decrease (27 +/- 9% of baseline after 15 min) in intracellular GSH, followed by resynthesis to levels significantly higher than baseline (335 +/- 40% after 24 h, P < 0.001). This elevation was prevented by acivicin, a gamma GT inhibitor. Menadione also caused a dose-dependent increase in gamma GT enzymatic activity (715 +/- 125% of control at 24 h after 15 min of exposure to 100 microM menadione, P < 0.001) that was prevented by actinomycin D. Western blot analysis indicated increased levels of gamma GT protein with increasing menadione. A concentration-dependent increase in gamma GT-mRNA was also observed. Previous investigation has demonstrated that an increase in gamma GT activity enhances the capacity of cells to utilize extracellular GSH. The findings presented here are consistent with a role for gamma GT in cellular adaptation to oxidative stress.

Deletion of 3 basepairs resulting in the loss of lysine-121 in the insulin receptor alpha-subunit in a patient with leprechaunism: binding, phosphorylation, and biological activity

We have identified a novel mutation of the human insulin receptor gene in a previously unreported patient with leprechaunism, leprechaun Rochester. This mutation consists of deletion of three nucleotides (GAA) in exon 2 and results in loss of the lysine-121 in the putative ligand-binding domain of the alpha-subunit. To analyze this mutation, we prepared a corresponding mutant insulin receptor by site-directed mutagenesis and expressed the receptor in Chinese hamster ovary cells. Although the mutant receptor displayed normal insulin binding, abnormalities were found in autophosphorylation and in phosphorylation of endogenous and exogenous protein substrates. These abnormalities consisted of increased basal kinase activity, but blunted insulin-stimulated responsiveness. Importantly, cells that expressed the mutant receptor showed markedly decreased insulin- and serum-stimulated DNA synthesis compared to untransfected control cells and cells transfected with the wild-type insulin receptor. These findings suggest that deletion of lysine-121 in conjunction with a presumed, but thus far unidentified, second mutant allele contributed significantly to the lethal insulin-resistant state in this patient with leprechaunism.

Fetal renal vein thrombosis, hydrops fetalis, and maternal lupus anticoagulant. A case report

Hydrops fetalis with fetal renal vein thrombosis in a mother with antiphospholipid antibody syndrome detected post-partum suggests an underlying pathogenetic association that may provide new strategies for treatment of a lethal disorder.

The transcription factor YY1 binds to negative regulatory elements in the human cytomegalovirus major immediate early enhancer/promoter and mediates repression in non-permissive cells

We have previously shown that repression of human cytomegalovirus (HCMV) major immediate early (IE) gene expression in non-permissive human teratocarcinoma (T2) cells is associated with a number of nuclear factors which bind to the imperfect dyad symmetry located in the modulator region upstream of the major IE enhancer as well as to the 21 bp repeat elements within the enhancer. Differentiation of T2 cells with retinoic acid (RA) results in a decrease in binding of some of these nuclear factors to these sites and deletion of these specific binding sites from major IE promoter/reporter constructs results in increased IE promoter activity in normally non-permissive cells. In this study, we demonstrate that the transcription factor YY1, which can negatively regulate the adeno-associated virus P5 promoter, directly binds to both the imperfect dyad symmetry and the 21 bp repeat elements in the HCMV major IE promoter/regulatory region and mediates repression of HCMV IE gene expression. This strongly suggests that YY1 plays an important role in regulating HCMV expression in non-permissive cells.

Regulation of neuropeptide-processing enzymes by nitric oxide in cultured astrocytes

Nitric oxide (NO), a recently discovered neurotransmitter, has been shown to have a cytostatic effect on cultured glia. A NO-generating agent, S-nitroso-N-acetyl-penicillamine (SNAP), was used to treat C6 glioma and primary cortical astrocytes. The levels of a monobasic peptide-processing enzyme activity and carboxypeptidase E activity were examined. The cellular levels of these two enzymes are specifically reduced in response to treatment with SNAP. A decrease of approximately 30-50% in these two enzyme activities was seen in both primary astrocytes and C6 glioma cells. This decrease in cellular enzyme activities is not due to increased secretion because the secreted activity is also reduced in response to SNAP treatment in both the glioma cells and the primary astrocytes. Removal of SNAP treatment causes the carboxypeptidase enzyme activity to return to control levels within 3 days. Northern and western blot analyses indicate that the reduced cellular level of carboxypeptidase E is not due to reduced expression of the messenger RNA or protein, suggesting that the SNAP treatment is affecting factors that influence carboxypeptidase E activity. Taken together, these results imply that NO is involved in the regulation of peptide biosynthetic enzymes and this could lead to the antimitogenic action of SNAP on glia.

Rat fibroblasts transfected with the human 70-kDa heat shock gene exhibit altered translation and eukaryotic initiation factor 2 alpha phosphorylation following heat shock

Heat shock inhibits translation in a wide variety of cells. After heating, eukaryotic initiation factor 2-alpha (eIF-2 alpha) becomes phosphorylated which prevents the binding of Met-tRNA to the 40s ribosomal subunit inhibiting initiation of translation. Thermotolerant cells demonstrate resistance to inhibition of translation by additional heating suggesting that heat shock proteins may help to maintain translational integrity following thermal stress. Here we have examined the effects of increased intracellular levels of hsp70 protein on translation and eIF-2 alpha phosphorylation using rat fibroblasts stably transfected with a cloned human hsp70 gene. We observed a decrease in the rate of translational inhibition following heat shock in both hsp70-transfected and thermotolerant cells. Upon recovery at 37 degrees C, both hsp70-transfected and thermotolerant cells exhibit a faster rate of translational recovery. Utilizing slab gel isoelectric focusing coupled with immunoblotting we demonstrate that 45 degrees C heat shock leads to a rapid 4-5-fold increase in eIF-2 alpha phosphorylation, with little difference seen between control cells and hsp70-transfected cells. However, dephosphorylation of eIF-2 alpha occurs faster in the hsp70-transfected cells. These results suggest that hsp70 may play a role in facilitating the dephosphorylation of eIF-2 alpha as well as reversing the inhibition of translation following heat shock.

Effects of background stress and anxiety on postoperative recovery

The effects of background stress and anxiety on both short- and long-term recovery were measured in 30 healthy patients undergoing general anaesthesia for day-case dental extractions. Standardised questionnaires presented pre-operatively, assessed psychological status in terms of trait and state anxiety and stress levels. State anxiety was again measured postoperatively; recovery was assessed with pre- and postoperative batteries of cognitive tasks. Correlation coefficients revealed that the level of background stress in the preceding 6 months correlated with physical parameters of recovery such as time taken for patients to open their eyes, perceived pain and increased postoperative morbidity. The study also demonstrated that high levels of state anxiety after surgery correlated with postoperative pain. Trait and state anxiety before surgery did not correlate with any parameters of recovery or postoperative morbidity.

Differential signal transduction of epidermal-growth-factor receptors in hormone-dependent and hormone-independent human breast cancer cells

In breast cancer, hormone dependency is inversely correlated with the number of surface epidermal-growth-factor (EGF) receptors on the tumor cells. In vitro, EGF stimulated only hormone-dependent immortalized human breast cancer cells to grow with an increased rate whereas hormone-independent cells were not affected by EGF. The number of EGF surface receptors is about 5-10-times smaller on hormone-dependent cells than on hormone-independent cells. Two cell lines representing the two cell types were used to demonstrate the signal-transduction capabilities of the EGF receptors. The two cell lines were the hormone-dependent MCF-7 cells and the hormone-independent MDA-MB-231 cells. Incubation at 37 degrees C for 15 min with 10(-8) M EGF increased the surface EGF-receptor density substantially on MCF-7 cells (50%) and reduced the number of these receptors on MDA-MB-231 cells to about 65% of the control. Both cell lines internalized a fluorescein-isothiocyanate-labeled EGF with similar kinetics. EGF triggered tyrosine phosphorylation of several targets in isolated MCF-7 cell membranes. One of these targets was shown by immunoprecipitation to be the EGF receptor. In MDA-MB-231 cell membranes, the EGF receptor was demonstrated to be the main target for tyrosine phosphorylation. The mRNA expression of the immediate early proto-oncogene c-fos was stimulated by EGF only in MCF-7 cells. In contrast, the mRNA of the EGF receptors was stimulated by EGF in both cell lines. These results demonstrate that, although EGF-binding sites are present on both cell lines, their signal-transduction capacity and activities are substantially different and resulted in a divergent response of the two cell types to EGF.

Plasma HDL levels are regulated by the catabolic rate of large particles of lipoprotein containing apo-A-I

Lp-A-I was isolated by immunoaffinity chromatography and then separated into two fractions of large and small Lp-A-I particles by conventional ultracentrifugation with a cut-off density of 1.125 g/ml. The large and small particle-rich fractions were then radiolabeled with [125I]-Na and [131I]-Na, respectively. Both of the labeled lipoproteins were injected (20 microCi, i.v.) simultaneously into normolipidemic rabbits. The FCR of the large Lp-A-I particles was much less than that of the small Lp-A-I particles (0.801 +/- 0.026/day vs. 2.227 +/- 0.067/day, P < 0.0001). These data indicate that the two particles have distinctly different metabolic pathways and that the lower FCR of larger Lp-A-I particles can effectively raise plasma HDL levels.

Role of tumor necrosis factor in neonatal sepsis

In order to assess the role of tumor necrosis factor (TNF) in neonatal sepsis, plasma TNF levels were determined by a method using L929 cells at the time of septic work-up in 67 neonates. Thirty-three patients with sepsis were found to have significantly higher TNF levels (533.33 +/- 468.74 U/ml; 1 U corresponding to 1.67 pg recombinant TNF) as compared with 34 non-sepsis patients (100.0 +/- 188.97 U/ml) and 30 healthy newborns (27.33 +/- 16.17 U/ml, P < 0.05, respectively). The upper limit of normal plasma TNF levels was 60 U/ml and the best cutoff value for predicting neonatal sepsis was 160 U/ml. This had remarkable sensitivity (88%), specificity (82%), positive predictive value (83%), and negative predictive value (88%). Plasma TNF levels were significantly associated with the occurrence of shock, organ failure, scleroma and outcome. Thus, anti-TNF antibodies might be used in protecting newborns from septic death.

Quantitative characterization of insulin-glucose response in Watanabe heritable hyperlipidemic and cholesterol-fed rabbits and the effect of cilazapril

A great deal of evidence suggests that insulin resistance, via hyperinsulinemia, contributes to hyperlipoproteinemia and coronary atherosclerosis. When Watanabe heritable hyperlipidemic (WHHL) rabbits, an animal model of familial hypercholesterolemia (FH), are compared with normolipidemic Japanese White (JW) rabbits, an elevated fasting plasma insulin level and a heightened plasma insulin response to an intravenous (i.v.) glucose challenge are found. To elucidate the mechanism behind this phenomenon, a two-compartment model of the glucose/insulin system was fitted to empirical time courses of glucose and insulin concentrations during an i.v. glucose tolerance test (IVGTT) by nonlinear least-square regression, and the model parameters such as the glucose utilization rate constant, insulin degradation rate constant, and pancreas sensitivity were determined. WHHL rabbits showed decreased values of glucose utilization and insulin degradation rate constants and slightly higher values of pancreas sensitivity. This suggests that insulin resistance occurs in extrapancreatic tissues, and that this may be attributable to insulin receptor and/or post-insulin receptor abnormalities. Cholesterol feeding did not significantly change glucose tolerance or insulin action in JW rabbits. The effects of an angiotensin-converting enzyme (ACE) inhibitor, cilazapril, on insulin resistance were also examined in WHHL and JW rabbits. A decreased insulin response to an i.v. glucose challenge and increased glucose utilization and insulin degradation rate constants were observed in WHHL rabbits that had been treated with cilazapril, indicating that cilazapril improved insulin resistance in WHHL rabbits, possibly by increasing the number of insulin receptors. No significant differences were found in glucose tolerance and insulin action in JW rabbits before and after cilazapril administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative molecular field analysis combined with physicochemical parameters for prediction of polydimethylsiloxane membrane flux in isopropanol

Comparative molecular field analysis (CoMFA) combined with various physicochemical parameters were used to develop three-dimensional quantitative structure-transportability relationships (3-D QSTR) to predict membrane flux for 108 aromatic and heteroaromatic compounds through polydimethylsiloxane (PDMS) membranes in isopropyl alcohol (IPA). Sybyl, a comprehensive computational molecular modeling package, was used to analyze the data. Optimized molecular models were selected using molecular modeling techniques. Partial least-squares (PLS) regression combined with crossvalidation or bootstrapping was used as the statistical method to establish the predictive models. Prediction was good for the steady-state flux using both steric and electrostatic field descriptors combined with a functional group classification technique. Predictive ability was substantially increased in a model using CoMFA descriptors along with log mole fraction solubility for the penetrants in isopropanol, a hydrophobic term, fchex, which is used to estimate the partition coefficient between cyclohexane and water, and the addition of an intramolecular hydrogen bonding (IHB) term. The crossvalidated r2 and the conventional r2 for this model were 0.951 and 0.973, respectively. Excellent predictions are demonstrated for the membrane flux of the compounds both inside and outside the data domain.

In vitro conversion of recombinant human proapolipoprotein A-I to apolipoprotein A-I

We recently investigated the in vivo conversion of recombinant human proapolipoprotein A-I (rh-Met-proapo A-I) from E. coli to apolipoprotein (apo) A-I in rabbits. In vitro incubation of rh-Met-proapo A-I with rabbit serum produced mature apo A-I3 isoproteins, as determined by the immunoblotting method. However, at the time we were unable to chemically confirm a newly produced protein band which appeared at the position of human apo A-I3. Since then, we have confirmed the amino acid sequence of the protein using a membrane protein sequence technique, and have concluded that it corresponds to human apo A-I3.

Association of the insulin receptor and phosphatidylinositol 3-kinase requires a third component

We have studied the interactions between the insulin receptor and PtdIns 3-kinase by a reconstitution system in vitro composed of highly purified PtdIns 3-kinase from rat liver and highly purified insulin receptors bound to insulin-agarose or to antibodies against insulin receptors. As a positive control, receptors for platelet-derived growth factor, which bind and phosphorylate PtdIns 3-kinase, were studied in parallel with insulin receptors. Our results indicate that the insulin receptor, regardless of its phosphorylation state, does not directly associate with purified PtdIns 3-kinase, whereas the autophosphorylated receptor does associate with PtdIns 3-kinase present in the crude CHO-cell lysate. Also, we could not detect phosphorylation of PtdIns 3-kinase by the insulin receptor, even through the receptor readily underwent autophosphorylation and phosphorylated an insulin-receptor substrate, poly(Glu-Tyr) (4:1). These findings argue that one or more cytosolic components link the receptor and the enzyme. Insulin-receptor substrate-1 (IRS-1) was evaluated as a potential linking protein. In the absence of ATP, IRS-1 did not facilitate the coupling of the phosphorylated insulin receptor to PtdIns 3-kinase. Thus IRS-1 is unlikely to be the component in crude CHO-cell lysate that couples PtdIns 3-kinase to the phosphorylated insulin receptor. However, the addition of ATP, which allows phosphorylation of IRS-1 by the insulin receptor, also enhances the coupling of PtdIns 3-kinase to the insulin receptor. In support of this idea, immunoprecipitates of IRS-1 from insulin-treated CHO cells were found to contain both the insulin receptor and PtdIns 3-kinase. In conclusion, the insulin receptor does not appear to phosphorylate or bind directly to PtdIns 3-kinase, regardless of the receptor's state of phosphorylation. Association of PtdIns 3-kinase with the insulin receptor is mediated by one or more components, one of which may involve an unidentified factor in cell lysate and another that apparently involves phosphorylated IRS-1.

Polymorphic site study at codon 347 of apolipoprotein A-IV in a Japanese population

In a population of Japanese subjects, we surveyed codon 347 of the apolipoprotein (apo) A-IV gene and found that the frequency of a rare allele at this point was extremely low compared to that in western populations. Only one of 850 unrelated samples showed mutation at the enzyme recognition site by agarose gel electrophoresis. However, direct sequencing of the coding region revealed that it did not result from the ACT (Thr) to TCT (Ser) mutation which has been reported in western countries, but from an ACT to ACG (Thr) mutation, which does not affect the primary structure of apo A-IV. Two additional family members showed the same point mutation at codon 347.

Plasma nitric oxide levels in newborn infants with sepsis

Nitric oxide is thought to play an important role in the mediation of the cardiovascular features of septic shock. We determined plasma levels of nitrite and nitrate (not differentiated in measurement) in neonates with sepsis and found these levels to be elevated at the time of entry compared with those of control subjects (p < 0.05); the levels were significantly higher in the patients with sepsis and shock than in those without shock (p < 0.05). Elevations of nitrite plus nitrate were correlated with tumor necrosis factor and severity of illness judged by pediatric risk of mortality (PRISM) scores at onset (p < 0.05). Of 8 newborn infants with a nitrite-plus-nitrate value > 200 mumol/L, 6 had septic shock; none of 12 not reaching that cutoff value had septic shock (p < 0.05). Levels of nitrite plus nitrate were elevated as much in gram-positive as in gram-negative sepsis. We conclude that the determination of circulating plasma levels of nitrite plus nitrate may be useful in forecasting the severity of illness and the occurrence of septic shock; therapeutic approaches associated with inhibition of nitric oxide synthesis may be worth trying in infants with septic shock.

Association between protective efficacy of antibodies to tumor necrosis factor and suppression of nitric oxide production in neonatal rats with fatal infection

In a rat model of fatal infection caused by Pseudomonas aeruginosa, the circulating level of nitrite/nitrate (NO2-/NO3-), a good indicator for nitric oxide production, was remarkably increased after elevation of circulatory tumor necrosis factor (TNF). Anti-TNF MAb cotreatment was shown to blunt hypoglycemia and hyperlacticemia and was associated with decreased mortality of septic animals. Moreover, anti-TNF MAb significantly reduced not only plasma TNF but also plasma NO2-/NO3- levels. Dexamethasone had a similar effects, and when anti-TNF MAb was used in combination with dexamethasone, the suppression of nitric oxide production and the protective efficacy were more remarkable compared with therapy with either anti-TNF MAb or dexamethasone alone. Our present data suggested that the protective efficacy of anti-TNF MAb may correlate with the suppression of nitric oxide production and also with a modulation in metabolic abnormalities in the septic newborn rats.

In vivo kinetics of lipoprotein(a) in homozygous Watanabe heritable hyperlipidaemic rabbits

In vivo kinetics of lipoprotein(a) [Lp(a)] were investigated in homozygous Watanabe heritable hyperlipidaemic (WHHL) rabbits (an animal model of familial hypercholesterolemia (FH)), and in normolipidemic Japanese White rabbits (controls). 125I-labelled Lp(a) and 131I-labelled LDL were simultaneously injected intravenously. Blood samples were then taken periodically. Kinetic parameters were calculated from the plasma radioactivity decay curves. The fractional catabolic rates (FCRs) of both Lp(a) and LDL (1.355 +/- 0.189 pools per day and 1.278 +/- 0.397 pools per day, respectively) in the WHHL rabbits were significantly (P < 0.005) smaller than those in the control rabbits (2.008 +/- 0.083 pools per day and 2.855 +/- 0.759 pools per day, respectively). In WHHL rabbits, the FCRs of Lp(a) and LDL were similar. However, in control rabbits, the FCR of Lp(a) was significantly (P < 0.01) smaller than that of LDL. In WHHL rabbit organs, the mean ratio of 125I-Lp(a): 131I-LDL, 48 h after injection, normalized to the corresponding isotope ratio in plasma, were 1.525, 1.020, 1.819 and 1.967, in liver, kidney, spleen and bile, respectively. These values were significantly higher than the corresponding values in control rabbits (0.590, 0.677, 0.862 and 0.766, respectively). Our data strongly suggest that Lp(a) clearance is not entirely dependent upon LDL receptors and may be mediated by some other mechanisms.

Combined therapy with probucol and pravastatin in hypercholesterolaemia. One year follow-up study

The effect of co-administration of low doses of pravastatin to hypercholesterolaemic patients already receiving long-term probucol treatment (mean 500-1,000 mg/day for 350 days) were investigated. Pravastatin 5 mg/day (Group 1; 12 m, 13 f; mean age 59.1 y) or 10 mg/day (Group 2; 8 m, 11 f; mean age 60.8 y) was administered, and blood was taken after 0, 3, 6, and 12 months. Both groups showed a significant reduction in serum total cholesterol (TC), phospholipid (PL), low density lipoprotein-cholesterol (LDL-C), LDL-triglyceride (TG), LDL-PL, apolipoprotein (apo) B, and apo E after the combined therapy. These levels were reduced more in Group 2 than in Group 1 subjects. In Group 2, significant falls in serum TG and apo CII were also observed. The changes in TC, PL, LDL-C, apo B, apo CII and apo E were dependent upon the dose of pravastatin, as assessed by two-way analysis of variance. Serum high density lipoprotein (HDL)3-C, apo AI and apo AII were slightly but significantly increased in both groups after 12 months of combined therapy, but the increase was not sufficient to reverse the probucol-induced lowering of the HDL level. We conclude that combined therapy resulted in a significant reduction in atherogenic lipoproteins and apolipoproteins, and an increasing dose of pravastatin (5 mg to 10 mg daily) made the lipid lowering effect more prominent. The reduction in serum HDL-C due to long-term probucol administration was not reversed by the addition of pravastatin.

The influence of phthalate esters on Leydig cell structure and function in vitro and in vivo

Phthalate esters are widely used in the manufacture of plastics and have been shown to cause testicular toxicity, purportedly, by targeting the Sertoli cell alone. Recent evidence, however, indicates that a paracrine control exists between Sertoli and Leydig cells and the breakdown of one component of this relationship is therefore detrimental to normal function. However, no data that explore the influence of testicular toxins on Leydig cell structure and function have been published hitherto. The preliminary studies reported here were initiated to test the hypothesis that phthalate intoxication may adversely alter Leydig cell structural and functional integrity. Four phthalate esters, namely, di(2-ethylhexyl) phthalate (DEHP, di-n-pentyl phthalate (DPP)., di-n-octyl phthalate (DOP), and diethyl phthalate (DEP) were investigated in vivo and their monoesters (MEHP, MPP, MOP, and MEP, respectively) in vitro for indications of Leydig cell toxicity in the rat. Rats were dosed by oral gavage with 2 g phthalate diester/kg/day in corn oil vehicle for 2 days, while Leydig cell primary cultures were incubated with 1,000 microM monoester for 2 hr. Light and electron microscopy were undertaken to determine the type and degree of any changes. Phthalate esters exerted a direct effect on Leydig cell structure and function (as determined by testosterone output) with correlation of the in vitro and in vivo effects of MEHP (DEHP) and MOP (DOP). No effects on Leydig cell structure or function were seen with MPP (DPP), although Sertoli cell cytoplasmic rarefaction and vacuolation were observed in vivo. DEP produced Leydig cell ultrastructural alterations in vivo. We conclude that individual phthalate esters may exert effects on both Sertoli and Leydig cells or one cell type alone.

In vivo kinetics of oxidatively modified HDL

The kinetics of oxidatively modified high-density lipoprotein (HDL) in vivo were investigated. 125I-labeled oxidized (Ox) HDL and 131I-labeled native (N) HDL were injected simultaneously into control and WHHL rabbits. The fractional catabolic rates of 125I-labeled Ox-HDL were significantly greater than those of 131I-labeled N-HDL in both control (2.52 +/- 0.36/day vs 0.94 +/- 0.02/day) and WHHL rabbits (4.07/day vs 1.32/day). Oxidized HDL was catabolized faster than native HDL and was taken up primarily by the liver, spleen, and kidney.

The effect of carbohydrate ingestion on performance during a 30-km race

Seven experienced endurance runners completed a 30-km road race on two occasions separated by 10 days. On each occasion the subjects consumed 250 ml of either a 5% carbohydrate (CHO) solution or nonflavored tap water (W) immediately prior to the start of the race, and 150 ml of the assigned fluid every 5 km thereafter. Performance time for the CHO trial was faster compared with the time recorded for the W trial (128.3 +/- 19.9 min vs. 131.2 +/- 18.7 min [p < 0.01] respectively). Running speed was maintained throughout the race in the CHO trial, whereas a decrease in the running speed occurred after 25 km (p < 0.05) in the W trial. No difference was found between the two trials in blood glucose concentration, plasma electrolyte concentrations, body weight loss, change in plasma volume, and rating of perceived exertion. Blood lactate concentration was higher at 25 km during the CHO trial compared with the W trial (p < 0.01), but plasma FFA and glycerol concentrations were lower at 30 km during the CHO trial than during the W trial (p < 0.05). In conclusion, this study shows that performance time for a 30-km road race is improved after ingesting a 5% CHO solution.

Effects of heparin and other glycosaminoglycans on elastin production by cultured neonatal rat lung fibroblasts

Proteoglycans are important structural elements of the extracellular matrix, and may contribute to the dynamic architecture of the lung and also influence pulmonary gas and solute exchange. The potential for proteoglycans and glycosaminoglycans to modulate the synthesis and deposition of elastin, another important extracellular matrix component of the lung, has not been established. Therefore the effects of glycosaminoglycans on the steady-state level of elastin mRNA, the incorporation of [3H]valine into tropoelastin, the distribution of soluble elastin in the medium and cell layer, and insoluble elastin deposition have been examined using cultured neonatal rat lung fibroblasts. Heparin decreases the soluble elastin content of the culture medium while increasing the soluble elastin content of the cell layer. This altered partitioning of soluble elastin is associated with an increase in steady-state elastin mRNA and an increase in the deposition of insoluble elastin in the extracellular matrix. Some of these effects may result from the binding of heparin to soluble elastin at physiological concentrations of NaCl. The galactosamine-containing glycosaminoglycans, chondroitin sulfate and dermatan sulfate, differ from heparin in that they increase the quantity of soluble elastin in the culture medium and decrease the deposition of insoluble elastin in the extracellular matrix. Proteoglycans, which are present in most elastic tissues, may participate in the regulation of elastin synthesis and deposition during periods of new elastin formation.

In vivo conversion of recombinant human proapolipoprotein AI (rh-Met-proapo AI) to apolipoprotein AI in rabbits

In vivo conversion of recombinant human proapolipoprotein AI (rh-Met-proapo AI) from E. coli to apolipoprotein (apo) AI was investigated. rh-Met-proapo AI was labeled with 125I, and then administered intravenously to rabbits. Blood was sampled periodically for 6 days. The plasma decay curves of radioiodinated rt-Met-proapo AI were similar to those of human mature apo AI (fractional catabolic rate (FCR); 1.018 +/- 0.090/day vs. 0.976 1 0.031/day, respectively). In vivo conversion of rh-Met-proapo AI to mature apo AI was examined by autoradiography of the isoelectric focusing (IEF) slab gel, i.e., the HDL fraction from each sampling point was semiquantitatively applied to IEF. It was found that the radioactivity of rh-Met-proapo AI migrated to more acidic isoproteins, the conversion was complete within 24 h, and the FCR of rh-Met-proapo AI was 9.20 +/- 1.34/day. Although the plasma decay curves of both human pro (rh-Met-proapo AI) and mature apo AI were significantly steeper than those of rabbit mature apo AI4 and apo AI5 (FCR; 0.703 +/- 0.027/day and 0.795 +/- 0.031/day, respectively), the conversion rate of human rt-Met-proapo AI to mature apo AI in rabbit was assumed to be 1:1. In vitro incubation of rh-Met-proapo AI with rabbit serum produced mature apo AI isoproteins, as determined by the apo AI immunoblotting method. Prediction of the amino acid sequence at the NH2 terminus of rabbit proapo AI showed that the prosegment consisted of an alpha helix with a high probability of a beta turn at Pro9, which is close to that in humans. Thus, (1) the proteolytic cleavage of proapo AI is an extracellular event, (2) the converting enzyme in rabbits can also process human proapo AI, (3) this converting enzyme does not specifically and directly attack the Gln6-Asp7 bond which links the carboxyl-terminal residue of the hexapeptide to the amino-terminal residue of human mature apo AI. The conformation of proapo AI at the NH2 terminus (alpha helix of the prosegment and a beta turn at Pro9) may have a key role in this cleavage, and (4) the examination of rh-Met-proapo AI in rabbits helps to explain the early events of HDL biogenesis.

Serum lipoprotein (a) levels in maintenance hemodialysis patients

To further understand lipoprotein (a) [Lp(a)] and atherosclerosis, we measured serum Lp(a), lipoprotein, and apolipoprotein levels in 55 patients (males, 24-73 years old) on maintenance hemodialysis, and compared them with those of 82 controls (males, 21-81 years old). The serum Lp(a) levels in patients on maintenance hemodialysis were significantly higher than those of the normal controls, while serum total cholesterol (TC), high-density lipoprotein-cholesterol, (HDL-C), HDL2-C, HDL3-C, apolipoprotein (apo) Al, apo All levels, and lecithin-cholesterol acyltransferase (LCAT) activities were significantly (p < 0.05) reduced in the patient group. The frequency distribution of serum Lp(a) levels in the patients was different from that in the control group, and no prognostic tendency of serum Lp(a) levels was noted by the etiology of renal failure as histologically determined by the renal biopsies. In the patient group, we also found that serum Lp(a) levels negatively correlated with serum triglycerides (TG) and total protein (TP) concentrations (p < 0.05), but no correlation was found between the duration of hemodialysis therapy or patient age and the serum levels of TC, TG, apo B and Lp(a) levels when tested for simple regression. Significant (p < 0.05) positive correlations were also found between TP and serum TG, apo B, and LCAT activities. These opposing tendencies of Lp(a) and serum TG, apo B, when measured against TP concentrations, indicate that serum TP levels may not affect serum lipoprotein and Lp(a) levels in the same direction. These data suggest that hemodialysis or end-stage renal disease itself, rather than hypoproteinemia, may hold the key to high serum Lp(a) levels in hemodialysis patients.

[Experimental study on kidney invigorating and lipid reducing decoction-yishen jiangzhi tang in the treatment of chronic renal failure]

In exploring the effect of treatment of supporting the body resistance on chronic renal failure, a chronic renal failure model of rat was created by gastroperfusion of adenine and evaluation was made on the therapeutic effect of Kidney Invigorating and Lipid Reducing Decoction (KILRD). The mental state and body weight of the treated group have recovered well with polyuria and proteinurea improving, BUN and Creatinine decreasing, which appeared to be superior to the naturally recovered group. Renal pathological examination showed that: although the renal parenchymal damage was not reversed but its compensation was satisfactory with compensatory hypertrophy appearing in unaffected nephron. The dominant reaction in the affected area was polynucleomacrocytosis, foreign body granulamatosis, and interstitial lymphocytic infiltration, the fibrosis was inevident, while the above-mentioned condition in the naturally recovered group was relatively more serious, with fibrosis being observed. It was indicated that KILRD could increase the compensatory capacity and immunity, promote protein synthetization and improve renal function. The study on KILRD proved to be a significant conservative medical treatment for chronic renal failure.

Preclinical studies on the anticancer activity of the somatostatin analog octreotide (SMS 201-995)

The antiproliferative effect of somatostatin-14 and its analog octreotide on in vitro pancreatic and breast tumor cells has led to the suggestion that octreotide may have further oncological indications in addition to gastroenteropancreatic tumors. To extend these in vitro observations, we evaluated the effect of octreotide in rodent models of pancreatic and breast tumors. Octreotide of 5 or 50 micrograms b.i.d. in nude mice bearing solid MiaPaCa pancreatic tumors (subline 21) or ZR-75-1 breast tumors induced significant inhibition of tumor growth from week 2 until the end of treatment at week 5. After 5 weeks the mean volume of ZR-75-1 tumors in animals treated with the 50-micrograms regimen was 48% that of control. Autoradiographic studies showed a high percentage (71%) of ZR-75-1 tumors to be somatostatin receptor-positive. In addition, the growth of ZR-75-1 cells in vitro was significantly inhibited by octreotide. The drug was also tested in a second breast cancer model, DMBA-induced mammary tumors in rats, and continuous administration of 10 micrograms/kg/h over 6 weeks led to an approximately 50% reduction in the number of tumors arising in the rat mammary gland. These data suggest that pancreatic and breast cancer may be among the malignant diseases clinically susceptible to octreotide.

Effects of manidipine and delapril on serum lipids, lipoproteins, and apolipoproteins in patients with mild to moderate essential hypertension: a randomized trial with one-year follow-up

Forty-five patients with mild to moderate essential hypertension were randomly assigned to receive 10 to 40 mg of manidipine HCl or 15 to 60 mg of delapril daily for 12 months. In the manidipine-treated group were 13 women and 5 men (mean age, 48.2 years) and in the delapril-treated group 11 women and 11 men (mean age, 53.7 years). Blood samples were taken at baseline and after 6 and 12 months of treatment and again at 2 months after treatment discontinuation. Significant reductions in blood pressure were observed in both treatment groups. The reduction in diastolic blood pressure was significantly greater in the manidipine-treated patients than in the delapril-treated patients; no significant between-groups differences in systolic blood pressure were noted. Heart rate increased significantly in the manidipine group. No changes in serum levels of total cholesterol, triglycerides, and high-density and low-density lipoprotein cholesterol were noted during or after treatment. In the manidipine group, a small but significant decrease in apolipoprotein (apo) A-I and an increase in lipoprotein(a) were found at 6 months and a significant increase in apo A-II and apo E at 12 months; in the delapril group a significant decrease in apo A-I was found at 6 months. The results indicate that both manidipine and delapril are lipid-neutral antihypertensive drugs, since neither drug greatly affected serum lipid metabolism.

[Application of serum somatomedin C level to assess the disease activity in patients with acromegaly]

Serum SMC level was measured in acromegalic patients with different disease activity. The serum SMC level of 10 untreated and 15 treated patients with active disease was 30.5 +/- 17.6 and 23.8 +/- 16.3 KU/L respectively. These levels were significantly higher than the value 2.7 +/- 2.8 KU/L in 7 patients during remitting state. The serum SMC level correlated with the basal and the nadir GH level and the area under the GH curve in glucose suppression test. The serum SMC levels in 6 patients with prolactinoma, 10 patients with Grave's disease and 8 patients with renal failure were all in normal range, but in 10 patients with liver cirrhosis it was 0.36 +/- 0.39 KU/L, which was significantly lower than the normal value. We concluded that serum SMC level is a good criterion for assessment of disease activity of acromegaly for it does not require a dynamic test and it does not increase in other diseases.

Effects of Chinese herbal drugs on serum lipids, lipoproteins and apolipoproteins in mild to moderate essential hypertensive patients

We investigated the effects of the traditional Chinese herbal drugs, Dai-saiko-to (D) and Saiko-ka-ryukotsuboreito (S) on blood pressure, pulse rates, serum lipids, lipoproteins and apolipoproteins in 30 patients with mild to moderate hypertension in an open, randomised trial. After the drug treatment, BP remained unchanged, but pulse rates declined significantly after 3 months in the S treated group. Serum total cholesterol and triglyceride values did not change, but high density lipoprotein-cholesterol increased significantly (P < 0.05) in both groups. Apo-AI (P < 0.1 in S group) and apo-AII (P < 0.05 in D group, P < 0.1 in S group) tended to increase 3 months after treatment. These data indicate that both of these traditional Chinese medicines have a preferential effect on lipid metabolism with little antihypertensive action.

Antiproliferative effects of the somatostatin analogue octreotide (SMS 201-995) on ZR-75-1 human breast cancer cells in vivo and in vitro

The somatostatin analogue octreotide (SMS 201-995) inhibits secretion and growth of certain tumor cells, and current efforts are directed toward the elucidation of its mode of antiproliferative action. In this study, the effect of octreotide on the growth of ZR-75-1 human breast cancer cells has been characterized in immunodeficient nude mice and in cell culture. These results have been related to the expression of somatostatin receptors in vivo and in vitro. Continuous infusion of 10 micrograms/kg/h of octreotide yielded plasma levels of 5.7 ng/ml and elicited highly significant growth inhibitory effects on solid ZR-75-1 breast tumors in nude mice. After 2 and 4 weeks of treatment, tumor volumes in the octreotide group were 39.1 and 36.7% of those of control animals treated with vehicle, respectively. Autoradiographic studies demonstrated that 8 of 12 ZR-75-1 tumors studied were somatostatin receptor positive. When ZR-75-1 tumor cells were exposed in vitro to nanomolar concentrations of octreotide, a dose-dependent inhibition of cell growth was observed in the presence of 5% fetal calf serum or under serum-free conditions using epidermal growth factor, insulin-like growth factor type I, or insulin as growth stimulus. In parallel receptor-binding experiments, ZR-75-1 cells were shown to express specific high-affinity somatostatin receptors (Kd value = 0.9 nM, Bmax = 6000 sites/cell). From these experiments, we conclude that octreotide is a powerful inhibitor of ZR-75-1 tumor cell growth in nude mice and in culture. This inhibitory action of octreotide and the presence of somatostatin receptors on ZR-75-1 tumor cells in vitro and in vivo suggest a direct, somatostatin receptor-mediated effect of octreotide.

Preclinical studies on the anticancer activity of the somatostatin analogue octreotide (SMS 201-995)

The antiproliferative effect of somatostatin-14 and its analogue, octreotide, on in vitro pancreatic and breast tumor cells has led to the suggestion that octreotide may have further oncological indications in addition to its use in the treatment of gastroentero-pancreatic (GEP) tumors. To extend these in vitro observations, we evaluated the effect of octreotide in rodent models of pancreatic and breast tumors. Octreotide at a dose of 5 micrograms or 50 micrograms twice a day in nude mice bearing solid MiaPaCa pancreatic tumors (subline 21) or ZR-75-1 breast tumors induced a significant inhibition of tumor growth from week 2 until the end of treatment at week 5. After 5 weeks, the mean volume of ZR-75-1 tumors in animals treated with the 50-micrograms regimen was 48% of that in controls. Autoradiographic studies showed that a high percentage (71%) of ZR-75-1 tumors were somatostatin receptor-positive. In addition, the growth of ZR-75-1 cells in vitro was significantly inhibited by octreotide. The drug was also tested in a second breast cancer model, 7,12-dimethylbenzanthracene (DMBA)-induced mammary tumors in rats, and continuous administration of 10 micrograms/kg/h over 6 weeks led to an approximate 50% reduction in the number of tumors arising in the rat mammary gland. These data suggest that pancreatic and breast cancer may be among the malignant diseases clinically susceptible to octreotide.

[The incidence of low birth weight infant in north China]

From September 1989 to August 1990, the incidence of low birth weight (LBW) infant was studied collaboratively in 8 areas in north China. 29,941 infants (14,003 males and 12,938 females) were investigated, 1,348 LBW infants included those of preterm and small for gestational age (SGA) term. The incidence of LBW infant was 5.00%. The incidence of male preterm (3.15%) was higher than that of female preterm (2.39%). The incidence of female SGA term (2.46%) was higher than that of male SGA term (1.82%). 52.09% of the infants with birth weight (BW) < 2,500g was of SGA term. 35-36 weeks premature infants accounted for 61.78% and 1,500-2,499g LBW infants for 93.28%. The incidence of SGA preterm (GA < 37 weeks) was 17.8%. In this study, the incidence of LBW infant was higher in Changchun and Huhehot than in other areas.