SUrface SEnsing of Translation (SUnSET), a Method Based on Western Blot Assessing Protein Synthesis Rates in vitro

As the most energy- and metabolite-consuming process, protein synthesis is under the control of several intrinsic and extrinsic factors that determine its fine-tuning to the cellular microenvironment. Consequently, variations in protein synthesis rates occur under various physiological and pathological conditions, enabling an adaptive response by the cell. For example, global protein synthesis increases upon mitogenic factors to support biomass generation and cell proliferation, while exposure to low concentrations of oxygen or nutrients require translational repression and reprogramming to avoid energy depletion and cell death. To assess fluctuations in protein synthesis rates, radioactive isotopes or radiolabeled amino acids are often used. Although highly sensitive, these techniques involve the use of potentially toxic radioactive compounds and require specific materials and processes for the use and disposal of these molecules. The development of alternative, non-radioactive methods that can be easily and safely implemented in laboratories has therefore been encouraged to avoid handling radioactivity. In this context, the SUrface SEnsing of Translation (SUnSET) method, based on the classical western blot technique, was developed by Schmidt et al. in 2009. The SUnSET is nowadays recognized as a simple alternative to radioactive methods assessing protein synthesis rates. Key features • As a structural analogue of aminoacyl-transfer RNA, puromycin incorporates into the elongating peptide chain. • Detection of puromycin-labeled peptides by western blotting reflects translation rates without the need for radioactive isotopes. • The protocol described here for in vitro applications is derived from the SUnSET method originally published by Schmidt et al. (2009).

The hexosamine pathway and coat complex II promote malignant adaptation to nutrient scarcity

We present adaptive mechanisms of resistance of lung adenocarcinoma to their harsh microenvironment, which typically contains a lower glucose concentration compared with normal tissue.

The glucose-requiring hexosamine biosynthetic pathway (HBP), which produces UDP-N-acetylglucosamine for glycosylation reactions, promotes lung adenocarcinoma (LUAD) progression. However, lung tumor cells often reside in low-nutrient microenvironments, and whether the HBP is involved in the adaptation of LUAD to nutrient stress is unknown. Here, we show that the HBP and the coat complex II (COPII) play a key role in cell survival during glucose shortage. HBP up-regulation withstood low glucose-induced production of proteins bearing truncated N-glycans, in the endoplasmic reticulum. This function for the HBP, alongside COPII up-regulation, rescued cell surface expression of a subset of glycoproteins. Those included the epidermal growth factor receptor (EGFR), allowing an EGFR-dependent cell survival under low glucose in anchorage-independent growth. Accordingly, high expression of the HBP rate-limiting enzyme GFAT1 was associated with wild-type EGFR activation in LUAD patient samples. Notably, HBP and COPII up-regulation distinguished LUAD from the lung squamous-cell carcinoma subtype, thus uncovering adaptive mechanisms of LUAD to their harsh microenvironment.

Pemetrexed Hinders Translation Inhibition upon Low Glucose in Non-Small Cell Lung Cancer Cells

Genetic alterations in non-small cell lung cancers (NSCLC) stimulate the generation of energy and biomass to promote tumor development. However, the efficacy of the translation process is finely regulated by stress sensors, themselves often controlled by nutrient availability and chemotoxic agents. Yet, the crosstalk between therapeutic treatment and glucose availability on cell mass generation remains understudied. Herein, we investigated the impact of pemetrexed (PEM) treatment, a first-line agent for NSCLC, on protein synthesis, depending on high or low glucose availability. PEM treatment drastically repressed cell mass and translation when glucose was abundant. Surprisingly, inhibition of protein synthesis caused by low glucose levels was partially dampened upon co-treatment with PEM. Moreover, PEM counteracted the elevation of the endoplasmic reticulum stress (ERS) signal produced upon low glucose availability, providing a molecular explanation for the differential impact of the drug on translation according to glucose levels. Collectively, these data indicate that the ERS constitutes a molecular crosstalk between microenvironmental stressors, contributing to translation reprogramming and proteostasis plasticity.

Glucose-based spiro-oxathiazoles as in vivo anti-hyperglycemic agents through glycogen phosphorylase inhibition

The design of glycogen phosphorylase (GP) inhibitors targeting the catalytic site of the enzyme is a promising strategy for a better control of hyperglycaemia in the context of type 2 diabetes. Glucopyranosylidene-spiro-heterocycles have been demonstrated as potent GP inhibitors, and more specifically spiro-oxathiazoles. A new synthetic route has now been elaborated through 1,3-dipolar cycloaddition of an aryl nitrile oxide to a glucono-thionolactone affording in one step the spiro-oxathiazole moiety. The thionolactone was obtained from the thermal rearrangement of a thiosulfinate precursor according to Fairbanks' protocols, although with a revisited outcome and also rationalised with DFT calculations. The 2-naphthyl substituted glucose-based spiro-oxathiazole 5h, identified as one of the most potent GP inhibitors (K_i = 160 nM against RMGPb) could be produced on the gram-scale from this strategy. Further evaluation in vitro using rat and human hepatocytes demonstrated that compound 5h is a anti-hyperglycaemic drug candidates performing slightly better than DAB used as a positive control. Investigation in Zucker fa/fa rat model in acute and subchronic assays further confirmed the potency of compound 5h since it lowered blood glucose levels by ∼36% at 30 mg kg^-1 and ∼43% at 60 mg kg^-1. The present study is one of the few in vivo investigations for glucose-based GP inhibitors and provides data in animal models for such drug candidates.

Epidermal Growth Factor Represses Constitutive Androstane Receptor Expression in Primary Human Hepatocytes and Favors Regulation by Pregnane X Receptor

Growth factors have key roles in liver physiology and pathology, particularly by promoting cell proliferation and growth. Recently, it has been shown that in mouse hepatocytes, epidermal growth factor receptor (EGFR) plays a crucial role in the activation of the xenosensor constitutive androstane receptor (CAR) by the antiepileptic drug phenobarbital. Due to the species selectivity of CAR signaling, here we investigated epidermal growth factor (EGF) role in CAR signaling in primary human hepatocytes. Primary human hepatocytes were incubated with CITCO, a human CAR agonist, or with phenobarbital, an indirect CAR activator, in the presence or absence of EGF. CAR-dependent gene expression modulation and PXR involvement in these responses were assessed upon siRNA-based silencing of the genes that encode CAR and PXR. EGF significantly reduced CAR expression and prevented gene induction by CITCO and, to a lower extent, by phenobarbital. In the absence of EGF, phenobarbital and CITCO modulated the expression of 144 and 111 genes, respectively, in primary human hepatocytes. Among these genes, only 15 were regulated by CITCO and one by phenobarbital in a CAR-dependent manner. Conversely, in the presence of EGF, CITCO and phenobarbital modulated gene expression only in a CAR-independent and PXR-dependent manner. Overall, our findings suggest that in primary human hepatocytes, EGF suppresses specifically CAR signaling mainly through transcriptional regulation and drives the xenobiotic response toward a pregnane X receptor (PXR)-mediated mechanism.

Mesenchymal stem cells seeded on a human amniotic membrane improve liver regeneration and mouse survival after extended hepatectomy

Liver failure remains the leading cause of post-operative mortality after hepatectomy. This study investigated the effect of treatment with allogenic mesenchymal stem cells (MSCs) on survival and liver regeneration 48 hr and 7 days after 80% hepatectomy in C57Bl/6 mice. To optimize their biodistribution, MSCs were grown on acellular human amniotic membranes (HAM) and applied as a patch on the remnant liver. This approach was compared with MSC infusion and HAM patch alone. Hepatectomized mice without any treatment were used as control group. Survival rate was calculated and biological and histopathological parameters were analysed to monitor liver function and regeneration. MSCs grown on HAM retained their ability to proliferate, to differentiate into osteoblasts and adipocytes and to respond to pro-inflammatory stimuli. Extended hepatectomy (80%) led to liver failure that resulted in death within 72 hr in 76% of mice. MSC infusion showed an early but transitory positive effect on survival. MSC/HAM patches stimulated regeneration and significantly improved survival rate (54% vs. 24% in the control group at 7 days). They also decreased the severity of hepatectomy-induced steatosis, suggesting a modulation of lipid metabolism in hepatocytes. MSCs were still present on HAM at Days 2 and 7 posthepatectomy. In conclusion, engineered tissue constructs that combine MSCs and HAM improve survival and liver regeneration after 80% hepatectomy in mice. These encouraging results pave the way to potential clinical application.

The WNT/β-catenin pathway is a transcriptional regulator of CYP2E1, CYP1A2, and aryl hydrocarbon receptor gene expression in primary human hepatocytes

The wingless-type MMTV integration site family (WNT)/β-catenin/adenomatous polyposis coli (CTNNB1/APC) pathway has been identified as a regulator of drug-metabolizing enzymes in the rodent liver. Conversely, little is known about the role of this pathway in drug metabolism regulation in human liver. Primary human hepatocytes (PHHs), which are the most physiologically relevant culture system to study drug metabolism in vitro, were used to investigate this issue. This study assessed the link between cytochrome P450 expression and WNT/β-catenin pathway activity in PHHs by modulating its activity with recombinant mouse Wnt3a (the canonical activator), inhibitors of glycogen synthase kinase 3β, and small-interfering RNA to invalidate CTNNB1 or its repressor APC, used separately or in combination. We found that the WNT/β-catenin pathway can be activated in PHHs, as assessed by universal β-catenin target gene expression, leucine-rich repeat containing G protein-coupled receptor 5. Moreover, WNT/β-catenin pathway activation induces the expression of CYP2E1, CYP1A2, and aryl hydrocarbon receptor, but not of CYP3A4, hepatocyte nuclear factor-4α, or pregnane X receptor (PXR) in PHHs. Specifically, we show for the first time that CYP2E1 is transcriptionally regulated by the WNT/β-catenin pathway. Moreover, CYP2E1 induction was accompanied by an increase in its metabolic activity, as indicated by the increased production of 6-OH-chlorzoxazone and by glutathione depletion after incubation with high doses of acetaminophen. In conclusion, the WNT/β-catenin pathway is functional in PHHs, and its induction in PHHs represents a powerful tool to evaluate the hepatotoxicity of drugs that are metabolized by CYP2E1.

In vitro infection of primary human hepatocytes by HCV-positive sera: insights on a highly relevant model

OBJECTIVE

Adult primary human hepatocytes (PHHs) support the complete infection cycle of natural HCV from patients' sera. The molecular details underlying sera infectivity towards these cells remain largely unknown. Therefore, we sought to gain a deeper comprehension of these features in the most physiologically relevant culture system.

DESIGN

Using kinetic experiments, we defined the optimal conditions to infect PHH and explored the link between cell organisation and permissivity. Based on their infectivity, about 120 sera were classified in three groups. Concentration of 52 analytes was measured in 79 selected sera using multiplexed immunobead-based analyte profiling.

RESULTS

PHH permissivity towards HCV infection negatively correlated with cell polarisation and formation of functional bile canaliculi. PHH supported HCV replication for at least 2 weeks with de novo virus production. Depending on their reactivity, sera could be classified in three groups of high, intermediate or low infectivity toward PHH. Infectivity could not be predicted based on the donors' clinical characteristics, viral load or genotype. Interestingly, highly infectious sera displayed a specific cytokine profile with low levels of most of the 52 tested analytes. Among them, 24 cytokines/growth factors could impact hepatocyte biology and infection efficiency.

CONCLUSIONS

We identified critical factors leading to efficient PHH infection by HCV sera in vitro. Overall, we showed that this cellular model provides a useful tool for studying the mechanism of HCV infection in its natural host cell, selecting highly infectious isolates, and determining the potency of drugs towards various HCV strains.

Comparison of hepatic-like cell production from human embryonic stem cells and adult liver progenitor cells: CAR transduction activates a battery of detoxification genes

In vitro production of human hepatocytes is of primary importance in basic research, pharmacotoxicology and biotherapy of liver diseases. We have developed a protocol of differentiation of human embryonic stem cells (ES) towards hepatocyte-like cells (ES-Hep). Using a set of human adult markers including CAAT/enhancer binding protein (C/EBPalpha), hepatocyte nuclear factor 4/7 ratio (HNF4alpha1/HNF4alpha7), cytochrome P450 7A1 (CYP7A1), CYP3A4 and constitutive androstane receptor (CAR), and fetal markers including alpha-fetoprotein, CYP3A7 and glutathione S-transferase P1, we analyzed the expression of a panel of 41 genes in ES-Hep comparatively with human adult primary hepatocytes, adult and fetal liver. The data revealed that after 21 days of differentiation, ES-Hep are representative of fetal hepatocytes at less than 20 weeks of gestation. The glucocorticoid receptor pathway was functional in ES-Hep. Extending protocols of differentiation to 4 weeks did not improve cell maturation. When compared with hepatocyte-like cells derived from adult liver non parenchymal epithelial (NPE) cells (NPE-Hep), ES-Hep expressed several adult and fetal liver makers at much greater levels (at least one order of magnitude), consistent with greater expression of liver-enriched transcription factors Forkhead box A2, C/EBPalpha, HNF4alpha and HNF6. It therefore seems that ES-Hep reach a better level of differentiation than NPE-Hep and that these cells use different lineage pathways towards the hepatic phenotype. Finally we showed that lentivirus-mediated expression of xenoreceptor CAR in ES-Hep induced the expression of several detoxification genes including CYP2B6, CYP2C9, CYP3A4, UDP-glycosyltransferase 1A1, solute carriers 21A6, as well as biotransformation of midazolam, a CYP3A4-specific substrate.

Aldehyde dehydrogenase activity promotes survival of human muscle precursor cells

Aldehyde dehydrogenases (ALDH) are a family of enzymes that efficiently detoxify aldehydic products generated by reactive oxygen species and might therefore participate in cell survival. Because ALDH activity has been used to identify normal and malignant cells with stem cell properties, we asked whether human myogenic precursor cells (myoblasts) could be identified and isolated based on their levels of ALDH activity. Human muscle explant-derived cells were incubated with ALDEFLUOR, a fluorescent substrate for ALDH, and we determined by flow cytometry the level of enzyme activity. We found that ALDH activity positively correlated with the myoblast-CD56⁺ fraction in those cells, but, we also observed heterogeneity of ALDH activity levels within CD56-purified myoblasts. Using lentiviral mediated expression of shRNA we demonstrated that ALDH activity was associated with expression of Aldh1a1 protein. Surprisingly, ALDH activity and Aldh1a1 expression levels were very low in mouse, rat, rabbit and non-human primate myoblasts. Using different approaches, from pharmacological inhibition of ALDH activity by diethylaminobenzaldehyde, an inhibitor of class I ALDH, to cell fractionation by flow cytometry using the ALDEFLUOR assay, we characterized human myoblasts expressing low or high levels of ALDH. We correlated high ALDH activity ex vivo to resistance to hydrogen peroxide (H₂O₂)-induced cytotoxic effect and in vivo to improved cell viability when human myoblasts were transplanted into host muscle of immune deficient scid mice. Therefore detection of ALDH activity, as a purification strategy, could allow non-toxic and efficient isolation of a fraction of human myoblasts resistant to cytotoxic damage.

Modular bioreactor for primary human hepatocyte culture: medium flow stimulates expression and activity of detoxification genes

Down-regulation of detoxification genes, notably cytochrome P450 (CYPs), in primary hepatocyte cultures is a long-standing and major concern. We evaluated the influence of medium flow in this model. Hepatocytes isolated from 12 different liver donors were cultured either in a multichamber modular bioreactor (MCmB, flow rate 250-500 μL/min) or under standard/static conditions, and the expression of 32 genes, enzyme activities and biological parameters were measured 7-21 days later. mRNA expression of genes involved in xenobiotic/drug metabolism and transport, including CYP1A1, 1A2, 2B6, 2C9, 3A4 (and activities for some of them), UDP-glucuronosyltransferase (UGT) 1A1, UGT2B4, UGT2B7, glutathione S-transferase (GSTα), and multidrug resistance protein 1 (MDR1) and MRP2, were specifically up-regulated by medium flow as compared with static controls in all cultures tested. In 2-week-old cultures, expression of detoxification genes reached levels close to or higher than those measured in freshly isolated hepatocytes. In contrast, CYP2D6 and most of other tested genes were not affected by medium flow. We conclude that medium flow specifically interferes with, and up-regulates, the activity of xenosensors and/or the expression of detoxification genes in primary human hepatocytes. Down-regulation of detoxification genes in conventional (static) cultures is therefore partly a consequence of the absence of medium circulation.

Isolation and culture of adult human liver progenitor cells: in vitro differentiation to hepatocyte-like cells

Highly differentiated normal human hepatocytes represent the gold standard cellular model for basic and applied research in liver physiopathology, pharmacology, toxicology, virology, and liver biotherapy. Nowadays, although livers from organ donors or medically required resections represent the current sources of hepatocytes, the possibility to generate hepatocytes from the differentiation of adult and embryonic stem cells represents a promising opportunity. The aim of this chapter is to describe our experience with the isolation from adult human liver and culture of non-parenchymal epithelial cells. Under appropriate conditions, these cells differentiate in vitro in hepatocyte-like cells and therefore appear to behave as liver progenitor cells.

The tangle of nuclear receptors that controls xenobiotic metabolism and transport: crosstalk and consequences

The expression of many genes involved in xenobiotic/drug metabolism and transport is regulated by at least three nuclear receptors or xenosensors: aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), and pregnane X receptor (PXR). These receptors establish crosstalk with other nuclear receptors or transcription factors controlling signaling pathways that regulate the homeostasis of bile acids, lipids, glucose, inflammation, vitamins, hormones, and others. These crosstalks are expected to modify profoundly our vision of xenobiotic/drug disposition and toxicity. They provide molecular mechanisms to explain how physiopathological stimuli affect xenobiotic/drug disposition, and how xenobiotics/drugs may affect physiological functions and generate toxic responses. In addition, the possibility that xenosensors may control other signaling pathways opens the way to new pharmacological opportunities.

Isolation, characterization, and differentiation to hepatocyte-like cells of nonparenchymal epithelial cells from adult human liver

Activation and proliferation of human liver progenitor cells has been observed during acute and chronic liver diseases. Our goal was to investigate the presence of these putative progenitors in the liver of patients who underwent lobectomy for various reasons but did not show any hepatic insufficiency. Hepatic lesions were evaluated by histological analysis. Nonparenchymal epithelial (NPE) cells were isolated from samples of human liver resections located at a distance from the lesion that motivated the operation and were cultured and characterized. These cells exhibited a marked proliferative potential. They did not express the classic set of stem cell/progenitor markers (Oct-4, Rex-1, alpha-fetoprotein, CD90, c-kit, and CD34) and were faintly positive for albumin. When cultured at confluence in the presence of hepatocyte growth factor and either epidermal growth factor or fibroblast growth factor-4, they entered a differentiation process toward hepatocytes. Their phenotype was quantitatively compared with that of mature human hepatocytes in primary culture. Differentiated NPE cells expressed albumin; alpha1-antitrypsin; fibrinogen; hepatobiliary markers such as cytokeratins 7, 19, and 8/18; liver-enriched transcription factors; and genes characterized by either a fetal (cytochrome P4503A7 and glutathione S-transferase pi) or a mature (tyrosine aminotransferase, tryptophan 2,3-dioxygenase, glutathione S-transferase alpha, and cytochrome P4503A4) expression pattern. NPE cells could be isolated from the liver of several patients, irrespective of the absence or presence of lesions, and differentiated toward hepatocyte-like cells with an intermediate hepatobiliary and mature/immature phenotype. These cells are likely to represent a resident progenitor population of the adult human liver, even in the absence of hepatic failure. Disclosure of potential conflicts of interest is found at the end of this article.

Inhibition of Notch signaling induces myotube hypertrophy by recruiting a subpopulation of reserve cells

During muscle differentiation, a population of quiescent undifferentiated myoblasts (reserve cells) emerges among mature muscle cells. However, the molecular mechanisms underlying such cell segregation and the characterization of this subpopulation of myoblasts remain to be determined. Notch is known to control the behavior and fate of murine muscle stem cells. In this study, we examined the role of Notch in myoblast segregation. We showed that inhibition of Notch activity by either overexpressing Numb or by using a pharmacological gamma-secretase inhibitor (DAPT) enhanced differentiation of murine and human myoblasts. This effect was not restricted to in vitro culture systems since DAPT-treated zebrafish embryos also showed increased differentiation. Using C2.7 myoblasts as a model, we showed that inhibition of Notch induced myotube hypertrophy by recruiting reserve cells that do not normally fuse. We further showed that endogenous Notch-signaling components were differentially expressed and activated in reserve cells with respect to Notch 1 and CD34 expression. We identified CD34 negative reserve cells as the subpopulation of myoblasts recruited to fuse into myotubes during differentiation in response to Notch inhibition. Therefore, we showed here that the activation of Notch 1 is important to maintain a subpopulation of CD34 negative reserve cells in an undifferentiated state.

IDS-C and IDS-sr: psychometric properties in depressed in-patients

Sixty-eight depressed in-patients were assessed at admission (DO), and after 5 days (D5), ten days (D10) and 28 days (D28) of antidepressant treatment, with the Inventory for Depressive Symptomatology-Clinician (IDS-C) and the Inventory for Depressive Symptomatology-Self-Rated (IDS-SR) (Rush et al., 1986), the Montgomery and Asberg Depression Rating Scale (MADRS) (Montgomery and Asberg, 1979) and the depression factor of the Symptom Check List (SCL-90R) (Derogatis, 1977), in order to assess IDS-C and IDS-SR psychometric properties in depressed in-patients and to compare IDS-C to MADRS and IDS-SR to the SCL-90R depression factor. Most of the IDS-C and IDS-SR items were significantly correlated to the final score and the Cronbach alpha coefficients were high (0.75 for the IDS-C and 0.79 for the IDS-SR). Principal Component Analyses (PCA) showed three factors for both IDS-C and IDS-SR: 'depression', 'anxiety/arousal' and 'sleep/appetite'. These results suggest satisfactory internal consistency of IDS-C and IDS-SR. Concurrent validity of the IDS-C with the MADRS was high (r = 0.81), as well as concurrent validity of the IDS-SR with the SCL-90R depression factor (r = 0.84). Concerning sensitivity to change, the four scales were able to discriminate between different levels of severity of depression. Moreover, considering paired t-tests on score changes, IDS-C sensitivity to change may be higher than MADRS sensitivity to change, this phenomenon being related to the number of items and degrees but not to the item contents. Contrary to IDS-C and MADRS, IDS-SR and SCL-90R depression factor were not different in terms of sensitivity to change. Finally, psychometric properties of IDS-C and IDS-SR in depressed in-patients are satisfactory and close to those obtained in depressed out-patients. The high sensitivity to change of the IDS-C may be an advantage for this scale as compared to the MADRS, especially in antidepressant drug trials.

Efficacy of a green tea extract rich in catechin polyphenols and caffeine in increasing 24-h energy expenditure and fat oxidation in humans

BACKGROUND

Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system.

OBJECTIVE

We investigated whether a green tea extract, by virtue of its high content of caffeine and catechin polyphenols, could increase 24-h energy expenditure (EE) and fat oxidation in humans.

DESIGN

Twenty-four-hour EE, the respiratory quotient (RQ), and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men. On 3 separate occasions, subjects were randomly assigned among 3 treatments: green tea extract (50 mg caffeine and 90 mg epigallocatechin gallate), caffeine (50 mg), and placebo, which they ingested at breakfast, lunch, and dinner.

RESULTS

Relative to placebo, treatment with the green tea extract resulted in a significant increase in 24-h EE (4%; P < 0.01) and a significant decrease in 24-h RQ (from 0.88 to 0.85; P < 0.001) without any change in urinary nitrogen. Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo (40%, P < 0.05). Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines.

CONCLUSIONS

Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se. The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis, fat oxidation, or both.

Once-weekly resistance exercise improves muscle strength and neuromuscular performance in older adults

OBJECTIVE

To determine the effect of frequency of resistive training on gain in muscle strength and neuromuscular performance in healthy older adults.

DESIGN

A randomized controlled trial with subjects assigned either to high-intensity resistance training 1 (EX1), 2 (EX2), or 3 (EX3) days per week for 24 weeks or to a control group (CO).

SETTING

An exercise facility at an academic medical center.

SUBJECTS

Forty-six community-dwelling healthy men (n = 29) and women (n = 17) aged 65 to 79 years.

INTERVENTION

Progressive resistance training consisting of three sets of eight exercises targeting major muscle groups of the upper and lower body, at 80% of one-repetition maximum (1-RM) for eight repetitions, either 1, 2, or 3 days per week.

MEASURES

Dynamic muscle strength (1-RM) using isotonic equipment every 4 weeks, bone mineral density and body composition by dual energy X-ray absorptiometry (DXA), and neuromuscular performance by timed chair rise and 6-meter backward tandem walk.

RESULTS

For each of the eight exercises, muscle strength increased in the exercise groups relative to CO (P < .01), with no difference among EX1, EX2 and EX3 groups at any measurement interval. Percent change averaged 3.9 +/- 2.4 (CO), 37.0 +/- 15.2 (EX1), 41.9 +/- 18.2 (EX2), and 39.7 +/- 9.8 (EX3). The time to rise successfully from the chair 5 times decreased significantly (P < .01) at 24 weeks, whereas improvement in the 6-meter backward tandem walk approached significance (P = .10) in the three exercise groups compared with CO. Changes in chair rise ability were correlated to percent changes in quadriceps strength (r = -0.40, P < .01) and lean mass (r = -0.40, P < .01).

CONCLUSIONS

A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance. Such improvement could potentially reduce the risk of falls and fracture in older adults.

Comparison of calcaneal ultrasound and DXA in young women

PURPOSE

The purpose of the study was to assess quantitative ultrasound (QUS) parameters in collegiate female gymnasts, a population whose training incorporates high-impact loading, which is particularly osteogenic, and to determine the discriminative capacity of this relatively new radiation-free technique compared with bone densitometry in a young healthy population.

METHODS

We studied 19 collegiate gymnasts and 23 healthy controls undergoing regular weight-bearing activity, matched for age (gymnasts 19.2 +/- 1.2, controls 19.9 +/- 1.6 yr) and body weight (gymnasts 56.7 +/- 3.7, controls 57.7 +/- 7.8 kg). QUS parameters of the calcaneus (broadband ultrasound attenuation (BUA), bone velocity (BV), and speed of sound (SOS)) were measured by a Walker Sonix UBA 575+. Bone mineral density (BMD; g x cm(-2)) of the lumbar spine, hip (femoral neck, trochanter, Ward's triangle) and whole body was assessed by dual energy x-ray absorptiometry (DXA, Hologic QDR 1000/W). Data analysis included unpaired two-tailed Student's t-tests, analysis of variance, Pearson product-moment, and Spearman rank-order correlations.

RESULTS

Regional and whole body BMD of gymnasts was greater than controls (P < 0.001), with the difference being 7-28%. Average QUS parameters of the right and left calcaneus were also higher (P < 0.001) in the gymnasts. BUA, BV, and SOS were significantly (P < 0.001) correlated to each bone site with r = 0.54-0.79. Analysis of receiver operating characteristic (ROC) curves indicated no significant difference in sensitivity and specificity for QUS and DXA measures.

CONCLUSIONS

These results indicate that QUS parameters of the calcaneus are higher in young women gymnasts compared to individuals who undergo regular weight-bearing activity and that QUS parameters are able to discriminate between these two groups in a similar manner as does regional and whole body BMD.

Concordance between self-report and clinician's assessment of depression

In order to assess differences between self-assessment and clinician's assessment of depression, 64 depressed in-patients were assessed for depressive symptomatology at admission (D0), 10 days (D10) and 28 days (D28) after the beginning of antidepressant treatment, using the Inventory for Depressive Symptomatology Clinician Rated (IDS-C) and the Inventory for Depressive Symptomatology Self-Rated (IDS-SR). Associated symptoms (SCL-90R) were assessed at D0 and personality dimensions (TCI) at D28. Although agreement was high between IDS-C and IDS-SR total scores, D0, D0-D10 and D0-D28 total scores were significantly different between IDS-C and IDS-SR, showing a higher sensitivity to change for IDS-C as compared to IDS-SR. Differences between IDS-C and IDS-SR were due mostly to mood items and not to somatic items. Discrepancies between self-assessment and clinician's assessment of depressive symptomatology were linked neither to age, sex, familial status, single/recurrent and length of episode, nor to depression severity, but to associated symptoms and, to a lesser extent, personality dimensions: patients over-estimating their depressive symptomatology change relative to the psychiatrist tended to score high on phobic anxiety, Cooperativeness (especially Social Acceptance) and Self-Transcendence (especially Self-forgetfulness) and vice-versa.

Agreement between 'time-blind' and 'time-non-blind' assessments of depressive symptomatology

In a 4-week study, two methods were used simultaneously in the assessment of depressive symptomatology with videotaped structured clinical interviews: a 'time-non-blind' (TNB) method (chronological order, observer aware of the previous duration of drug treatment) and a 'time-blind' (TB) method (no chronological order, rater unaware of the previous duration of treatment). Sixty newly admitted depressed inpatients with Montgomery-Asberg Depression Rating Scale scores higher than 20 were assessed before (D0), after 10 days (D10) and after 28 days (D28) of antidepressant treatment. Agreement between TNB and TB methods on the Montgomery-Asberg Depression Rating Scale, measured by intra-class correlation coefficients, was good at D0 (0.68), excellent at D10 (0.81) and D28 (0.86), but not significantly different between D0, D10 and D28. The statistical method of Bland and Altman (1986) was also used to evaluate the degree of agreement. Results of this second analysis were in accordance with the intra-class correlation coefficient results, and showed significantly (P < 0.05) higher D0-D28 and D10-D28 intrasubject changes with the TB method, which were largely accounted for by some particular items (inner tension, pessimism, lassitude). With the Clinical Global Impression-Severity score, the Bland and Altman method failed to show significant differences between the two methods, and compared with the Montgomery-Asberg Depression Rating Scale, intra-class correlation coefficients were lower with larger confidence intervals, suggesting that global ratings are less reliable than itemized symptom ratings.

Lack of association of anabolic hormone status and muscle strength with regional and whole body bone mineral density in healthy men aged 60-79 years

This study investigated the capacity of muscle strength and anabolic hormone status to predict regional and whole body bone mineral density (BMD) in older men. Fifty-two healthy men aged 60-79 years served as subjects. BMD of the lumbar spine, proximal femur, upper and lower limbs, and whole body was assessed by dual X-ray absorptiometry. Dynamic muscle strength for several upper and lower body muscle groups was determined by the one-repetition maximum and isometric grip strength by dynamometry. Anabolic hormone status was assessed by the ratio of testosterone (T) to sex hormone binding globulin (SHBG), given as the free androgen index (FAI), and the ratio of insulin-like growth factor I (IGF-I) to IGF binding protein-3 (IGFBP-3). Age was associated with declines in dynamic strength and the log FAI. In stepwise regression analysis, only body mass was an independent predictor of whole body and upper limb BMD (R2 = 0.13), and hip adductor strength predicted the Ward's triangle (R2 = 0.14). For lumbar spine BMD, triceps extensor strength was significantly correlated (r = 0.36, p < 0.01), while no strength or hormonal variable was associated with the femoral neck, trochanter, or lower limb. The lack of association between muscle strength and BMD was generally unaltered after controlling for hormone status and body mass. There was no difference in BMD when analyzed by tertiles of log FAI or IGF-I/IGFBP-3 or by tertiles of muscle strength. These results suggest that in healthy community-dwelling men in the seventh and eighth decade, muscle strength and hormonal status are not significant contributors to regional or whole body BMD.

Stability of recombinant vaccinia-rabies vaccine in veterinary use

Wildlife vaccination depends on vaccines which can be orally administered by a baiting system. Therefore only two possibilities exist: either the use of attenuated strains of viruses, or recombinant vector viruses. As far as rabies is concerned, the choice of the recombinant vaccinia-rabies virus was made because it was safer and more stable. An in vitro stability study of the recombinant product compared to wild rabies virus at different temperatures (4 degrees C, 20 degrees C, 37 degrees C, 45 degrees C) showed that the recombinant virus was more stable. The stability of the recombinant virus was also tested under field conditions; besides natural freezing and thawing cycles, the virus titre remained unchanged in the bait for a month. Taking into account the fact that all baits are eaten by wild animals within this period, one can assume that the vaccine is efficacious for all baiting animals in field conditions. The stability of the recombinant vaccinia-rabies vaccine is of considerable interest in such uncontrolled conditions.

Applications of canarypox (ALVAC) vectors in human and veterinary vaccination

This paper presents data derived from safety and efficacy studies of ALVAC-based rabies and feline leukemia virus (FeLV) vaccine candidates in target species. Inoculation of the ALVAC-RG recombinant was well tolerated in all species including humans and very young dogs. Protection induced in dogs against rabies challenge was long-lasting and could be elicited in the face of high levels of maternally-derived neutralizing antibody. Parenteral inoculation of cats with an ALVAC-FeLV recombinant was safe and induced protection against persistent infection following oro-nasal FeLV challenge.

Protection of mice and swine from pseudorabies virus conferred by vaccinia virus-based recombinants

Glycoproteins gp50, gII, and gIII of pseudorabies virus (PRV) were expressed either individually or in combination by vaccinia virus recombinants. In vitro analysis by immunoprecipitation and immunofluorescence demonstrated the expression of a gII protein of approximately 120 kDa that was proteolytically processed to the gIIb (67- to 74-kDa) and gIIc (58-kDa) mature protein species similar to those observed in PRV-infected cells. Additionally, the proper expression of the 90-kDa gIII and 50-kDa gp50 was observed. All three of these PRV-derived glycoproteins were detectable on the surface of vaccinia virus-PRV recombinant-infected cells. In vivo, mice were protected against a virulent PRV challenge after immunization with the PRV glycoprotein-expressing vaccinia virus recombinants. The coexpression of gII and gIII by a single vaccinia virus recombinant resulted in a significantly reduced vaccination dose required to protect mice against PRV challenge. Inoculation of piglets with the various vaccinia virus-PRV glycoprotein recombinants also resulted in protection against virulent PRV challenge as measured by weight gain. The simultaneous expression of gII and gp50 in swine resulted in a significantly enhanced level of protection as evaluated by weight evolution following challenge with live PRV.

Freeze-dried vaccine against Rinderpest: stability and activity study

A freeze-dried vaccine against Rinderpest was prepared from modified virus multiplied in calf kidney cell culture. Characteristics of the vaccine are as follows: high titre after freeze-drying (10(4) CCID50/dose), well-adapted freeze-drying stabilizer which ensures maintenance of the infective titre of the vaccinal virus, even under severe conditions (3.5 days at +45 degrees C), use of an appropriate solvent: magnesium sulphate molar solution or more simply physiological saline (for stability after reconstitution even at high temperatures--up to 4 h at +45 degrees C). The activity of the vaccine, tested in cattle by antibody titration and resistance to specific challenge perfectly satisfies requirements set by the WHO and OIE.

Feline infectious peritonitis: present knowledge

The purpose of this paper is to take stock of the knowledge gained over the last few years on Feline Infectious Peritonitis in a synthetic way.

Apart from the bibliographical study regarding the works of numerous authors, we state our results concerning the study of the experimental reproduction of the disease.

From all the cat infectious diseases, Feline Infectious Peritonitis is the clinical entity the most recently evidenced. In this paper we shall state the elements now clearly established on this disease but numerous points are still to be made clear. Contagious disease of viral origin, it affects domestic and wild Felidae. Clinically, in its most typical form, it is characterised by the progressive development of an exudative sero-fibrinous peritonitis and a febrile and gradual weakness of the general condition. It slowly and regularly develops into death.