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Sudden cardiac death (SCD) is the leading cause of death during exercise for athletes younger than 35 years. Structural cardiac abnormalities are responsible for the majority of SCDs among competitive athletes. The screening protocol that is best for detecting athletes at risk for SCD has been the subject of considerable and long-standing debate. The American Heart Association recommends the use of a 14-element history and physical examination (HP), whereas European standards call for a focused HP and 12-lead electrocardiogram (ECG). The use of ECG screening has been repeatedly rejected in the United States because of the high rate of false-positive results and an abundance of evidence suggesting that it is a cost-ineffective tool for screening. Attempts have also been made to prescreen athletes for cardiac disease with echocardiography (ECHO) performed by a cardiologist; however, this technique also proved to be cost-ineffective. The use of ECHO performed by a frontline physician reflects recent advancements in ultrasound technology utilization, including the advent of portable ultrasound, and introduces a new, promising screening method to the debate. Portable ECHO by a frontline physician (PEFP) has the ability to directly visualize structural components of the heart that are part of the gold standard ECHO evaluation performed by a cardiologist. The Early Screening for Cardiac Abnormalities with Preparticipation Echocardiography (ESCAPE) protocol developed at Northeastern University is the first attempt to implement the PEFP. Initial inquiries into the reliability and feasibility of the PEFP are promising. Measurements obtained by frontline physicians were not statistically different from those obtained by a cardiologist, focused ECHO was found to reduce the referral rate to cardiology by 33%, and PEFP was completed significantly faster than HP and an ECG. Early results are encouraging, but continued research to support the widespread use of PEFP for preparticipation examination in all competitive athletes is needed prior to recommending implementation.

As a physician, coach, or trainer, we see athletes as healthy, physically fit, and able to tolerate extremes of physical endurance. It seems improbable that such athletes may have, on occasion, underlying life-threatening cardiovascular abnormalities. Regular physical activity promulgates cardiovascular fitness and lowers the risk of cardiac disease. However, under intense physical exertion and with a substrate of significant cardiac disease—whether congenital or acquired— athletes may succumb to sudden cardiac death. The deaths of high-profile athletes receive much attention through the national news media, but there are also deaths of other athletes. With repetitive, intense physical exercise, the heart undergoes functional and morphologic changes. Knowledge of those changes may help one identify cardiovascular abnormalities that can cause sudden death from the heart known as an “athlete's heart.” This article will review cardiovascular diseases that may limit an athlete's participation in sports and that may put an athlete at risk for sudden cardiac death. It also reviews the extent and limitations of the cardiovascular preparticipation screening examination. Team physicians, coaches, and trainers must understand the process of evaluation of a symptomatic athlete that may indicate significant cardiac abnormalities. Finally, guidelines to determine eligibility of athletes with cardiovascular disease to return to sports will be reviewed.

Objectives We have developed the Early Screening for Cardiovascular Abnormalities With Preparticipation Echocardiography protocol to improve false-positive rates, reduce referrals, and broaden the spectrum of disease that can be captured through preparticipation screening of athletes. This study documents the first application of this protocol and uses case analysis to discuss the potential utility of portable sonography in screening. Methods Sixty-five male collegiate athletes, aged 18 to 25 years, were prospectively enrolled. Each athlete was screened with a history and physical examination, electrocardiography (ECG), and focused echocardiography performed by a noncardiologist sports medicine physician. The history and physical examination were based on the 12-element American Heart Association recommendations; 2010 European Society of Cardiology criteria were used to screen ECGs. Focused physician-operated echocardiography was performed to assess for hypertrophic cardiomyopathy and aortic root dilatation. Athletes screening positive were referred to a cardiologist. Results Most of the athletes (n = 59) did not screen positive by any screening modality. Three athletes screened positive on ECG but had normal focused echocardiographic findings. Three athletes screened positive by history and physical examination but had normal ECG and focused echocardiographic findings. All athletes screening positive were referred to a cardiologist and eventually cleared for sports participation. No athlete screened positive by focused echocardiography alone. Focused echocardiography was able to reduce the referral rate for hypertrophic cardiomyopathy by 33% and obtained measurements statistically similar to those of formal echocardiography. Conclusions This study provides evidence that focused physician-operated echocardiography can improve false-positive rates and broaden the spectrum of disease that is detectable through preparticipation screening of athletes.

After presenting the characteristics and the data acquired in an industrial evacuated kiln, a simplified analysis of heat and mass transfers is proposed. This analysis is based on the existence of a evaporization front determining two zones in the longitudinal direction : -a dried zone in which moisture is less than 30 % -a wet zone in which moisture is still at its initial value. Such a hypothesis allows to study transfers transversally first, then longitudinally. Both equation systems ore linked by conditions of continuity for mass and energy. This study allows to determine the shapes of the temperature and pressure curves in the longitudinal direction. The linearity of the variation of the average drying velocity versus the average moisture content of the board is also proved. Finally, the modeling of mechanical phenomena thanks to a finite element program shows the rupture zones appearing during the drying process.

OBJECTIVES The purpose of this study was to investigate whether sports medicine physicians can obtain accurate measurements of the aortic root in young athletes. METHODS Twenty male collegiate athletes, aged 18 to 21 years, were prospectively enrolled. Focused echocardiography was performed by a board-certified sports medicine physician and a medical student, followed by comprehensive echocardiography within 2 weeks by a cardiac sonographer. A left parasternal long-axis view was acquired to measure the aortic root diameter at the sinuses of Valsalva. Intraclass correlation coefficients (ICCs) were used to assess inter-rater reliability compared to a reference standard and intra-rater reliability of repeated measurements obtained by the sports medicine physician and medical student. RESULTS The ICCs between the sports medicine physician and cardiac sonographer and between the medical student and cardiac sonographer were strong: 0.80 and 0.76, respectively. Across all 3 readers, the ICC was 0.89, indicating strong inter-rater reliability and concordance. The ICC for the 2 measurements taken by the sports medicine physician for each athlete was 0.75, indicating strong intra-rater reliability. The medical student had moderate intra-rater reliability, with an ICC of 0.59. CONCLUSIONS Sports medicine physicians are able to obtain measurements of the aortic root by focused echocardiography that are consistent with those obtained by a cardiac sonographer. Focused physician-performed echocardiography may serve as a promising technique for detecting aortic root dilatation and may contribute in this manner to preparticipation cardiovascular screening for athletes.

OBJECTIVES The purpose of this study was to investigate whether sports medicine physicians can use portable echocardiography to obtain measurements pertinent to hypertrophic cardiomyopathy. METHODS Thirty male collegiate athletes, aged 18 to 21 years, were prospectively enrolled. Focused portable echocardiography was performed by a board-certified sports medicine physician and a resident physician, followed by comprehensive echocardiography within 2 weeks by a registered diagnostic cardiac sonographer. A left parasternal long-axis view was acquired to measure 3 dimensions: (1) end-diastolic interventricular septal thickness (IVSd), (2) end-diastolic left ventricular internal diameter (LVIDd), and (3) end-diastolic left ventricular posterior wall thickness (LVPWd). RESULTS Intraclass correlation coefficients between the sports medicine physician and the sonographer were strong: 0.77 for IVSd, 0.73 for LVIDd, and 0.64 for LVPWd. Intraclass correlation coefficients between measurements by the resident physician and sonographer were strong to moderate: 0.61 for IVSd, 0.62 for LVIDd, and 0.63 for LVPWd. Across all 3 readers, intraclass correlation coefficient calculations were 0.77 for IVSd, 0.81 LVIDd, and 0.75 for LVPWd, which indicated strong inter-rater reliability. CONCLUSIONS Sports medicine physicians are able to obtain measurements relevant to the diagnosis of hypertrophic cardiomyopathy with focused portable echocardiography that are consistent with comprehensive echocardiography by a registered sonographer.

Objective To determine risk factors for cardiac complications following total joint replacement (TJR) surgery. Methods We performed a case–control study of patients who had undergone a primary or revision total knee or total hip replacement surgery. Cases consisted of those who received a TJR and experienced a cardiac complication during the surgical admission period (myocardial infarction [MI], congestive heart failure [CHF], unstable angina, arrhythmia, symptomatic hypotension, or pulmonary embolus). Controls consisted of those who received a TJR and did not experience a cardiac complication during the surgical admission period. Controls were matched to the cases for age at surgery, year of surgery, and surgeon. Case and control status and identification of potential risk factors were ascertained by review of medical records. Conditional logistic regression analysis was used to identify independent predictors of cardiac complications. Results The sample included 209 cases and 209 controls. Factors associated with a higher risk of cardiac complications included a history of arrhythmia (adjusted odds ratio [OR] 2.6 [95% confidence interval (95% CI) 1.5–4.3]), a history of coronary artery disease, MI, CHF, or valvular heart disease (OR 1.6 [95% CI 0.9–2.6]), revision surgery (OR 2.2 [95% CI 1.2–3.9]), and bilateral surgery (adjusted OR 3.5 [95% CI 1.6–8.0]). Even though controls were matched for age (within age brackets), age was still associated with a higher risk of cardiac complications (OR 1.7 [95% CI 0.9–3.4]). Conclusion This case–control study identified 2 new risk factors for cardiac complications following TJR: bilateral and revision surgery. The study also confirmed previously documented risk factors, including older age at surgery and a history of arrhythmia and of other cardiac problems. These findings should help clinicians anticipate and prevent cardiac complications following TJR surgery.

We briefly introduce the main results obtained in our laboratory about high temperature drying kinetic of softwood and hardwood. We point out during drying the acceleration effect of pressure gradient in vapour phase which develops in the wood. Then we give the main experimental results carried out on a small industrial kiln which can dry wood boards with moist air and superheated steam at high temperature till 180°C and velocity above to 6 m/s. The drying process is completely automated. Tested species are : beech, poplar, fir and maritime pine. We show that the drying kinetics are almost the same using the industrial kiln or the wind tunnel and we define for different board thicknesses, temperatures and velocities the optimal sequences of the process. The influence on the quality of the pretreatment, the various drying periods and the post-steaming is of importance.

– Bladder neck cysts arise from a central degeneration of von Brunn nidi and are found casually during ultrasound, explaining obstructive symptomatology of which the patient sometimes complains. Endorectal ultrasound is essential for identifying this pathology and for a differential diagnosis between the various cystic formations of the prostate and the urogenital sinus. This paper reports two recent clinical cases related to this pathology.

Interleukin (IL)-18, a newly discovered cytokine produced primarily by macrophages, has been shown to induce gamma interferon (IFN-gamma) production by natural killer cells, to induce the T helper type 1 response. To further elucidate the role of this cytokine in uncomplicated malaria caused by Plasmodium falciparum, serum levels of IL-18, and gamma interferon (IFN-gamma), determined by an immunoenzymatic assay, were analyzed in 40 adult patients, and in 15 healthy control subjects. A significant increase in serum levels of IL-18 was observed in patients with uncomplicated P. falciparum malaria on admission, whereas serum levels of IFN-gamma tended to increase although not significantly. Serum levels of IL-18 decreased three days later, but still remained significantly high, whereas IFN-gamma levels returned to normal levels compared to the controls. No significant correlation was found between parasitemia and serum levels of IL-18 and IFN-gamma. The increase of IL-18 levels during acute and recovery phases of uncomplicated P. falciparum malaria may reflect a proinflammatory role of IL-18 in these patients. An early and effective immune response regulated by proinflammatory Th1 cytokines, including tumor necrosis factor (TNF), interleukin (IL)-12, and possibly IFN-gamma may limit the progression from uncomplicated malaria to severe and life-threatening complications.

Cells monitor and respond to extracellular signals from polypeptide growth factors by the induction of a genetic program. Although poorly understood at the molecular level, the biological activity of growth factors is believed to be mediated by the regulation of specific sets of genes. We have isolated a number of cDNAs, the expression of whose corresponding RNAs is induced by FGF-4 (K-FGF) in murine NIH3T3 fibroblasts. The cDNAs (FIN, for FGF-inducible) were isolated using a strategy of subtractive hybridization designed to yield 'late' genes which compared transformed 3T3 cells that constitutively produce FGF-4 with their normal counterpart. The 21 independent cDNAs isolated were found to correspond to known genes (FIN1-12), or novel genes (FIN13-21). Expression of the FIN genes is induced in response to FGF-4 as well as to serum in NIH3T3 cells with delayed kinetics, with maximum stimulation occurring 12-18h after growth factor treatment. Induction requires protein synthesis and is mostly transcriptional. FIN1-12 encode a broad range of previously described genes, some of which are proposed to have an important role in cell proliferation. The novel clones include a putative serine-threonine phosphatase (FIN13) and a gene with homology to NTP-binding proteins (FIN16). The distribution of expression of the novel FIN clones in adult mouse tissues was highly restricted, although most were expressed in embryos. While expression of novel FIN cDNAs was strongly regulated in NIH3T3 cells, induction of differentiation in PC-12 cells by FGF-4 (as well as by NGF) did not result in significant induction of expression, suggesting that most of the FIN genes are proliferation-specific. Chromosomal localization of novel FIN clones indicated that each segregated independently to separate mouse chromosomes.

The temperature-sensitive BN51 cell cycle mutant of BHK cells arrests in G1 at the nonpermissive temperature (39.5 degrees C). We have previously reported cloning the gene which complements this mutation. The complementing gene encodes a highly charged protein with a basic amino-terminal domain and an acidic carboxyl-terminal domain. We have recently found that the predicted BN51 protein shows significant homology to the 53 kilodalton subunit of RNA polymerase C (III) from Saccharomyces cerevisiae. Consistent with this, antibodies raised to fusion proteins containing BN51 coding sequences and antipeptide antibodies reveal that the BN51 gene encodes a 48 kilodalton protein which appears to be located primarily in the nucleus following subcellular fractionation and by immunohistochemistry. Analysis of RNA polymerase III activity in temperature-sensitive BN51 cells by nuclear runoff transcription assay reveals a marked drop in RNA polymerase III transcription after 48 h at the nonpermissive temperature (39.5 degrees C). This is correlated with a significant decrease in low molecular weight RNAs after 48 h at 39.5 degrees C. In addition, RNA polymerase III activity in S100 extracts of BN51 cells is more sensitive to heat inactivation at 39 degrees C than control extracts from BHK cells. When the yeast gene is introduced into the BN51 cells in a mammalian expression vector, it weakly complements the BN51 mutation in that it prevents cell death at 39.5 degrees C. The mechanism by which inhibition of RNA polymerase III activity leads to arrest in G1 is unclear but is not due to a marked decrease in total protein synthesis.

Using retrovirus-mediated gene transfer into neural transplants, we have expressed the human K-fgf/hst oncogene in the central nervous system. Single-cell suspensions of fetal rat brains were removed at embryonic days 13 and 14, exposed to a retroviral vector encoding the K-fgf oncogene and stereotaxically implanted into the caudate putamen of syngenic adult Fisher rats. Recipient animals were sacrificed at intervals of 6-16 months without evidence of neurological impairment. Mock-infected grafts showed the characteristic histopathological appearance of organotypically differentiated neural transplants. In contrast, grafts exposed to the K-fgf gene exhibited abundant capillary proliferation and capillary angiomas. By in situ hybridization analysis and immunohistochemistry, expression of K-fgf was detected in neural cells adjacent to vascular proliferations. Neurons and glia with abundant K-fgf transcripts were morphologically unaffected. In order to examine the transforming potential of the K-fgf gene in the nervous system, we combined retrovirus-mediated transfer of the K-fgf oncogene with a single transplacental exposure of the donor animals to the neurotropic carcinogen N-ethyl-N-nitrosourea (NEU). However, this combination of transforming agents did not result in tumor formation in the grafts. These results provide evidence for a powerful angiogenic effect of K-fgf on the developing brain in vivo.

We have cloned a murine cDNA on the basis of homology to the tyrosine kinase domain of the bek fibroblast growth factor receptor. This cDNA encodes a putative tyrosine kinase receptor with a unique structural pattern in its extracellular domain. It is a new member of the immunoglobulin superfamily with two immunoglobulin-like domains. It also contains two fibronectin type III domains which are found on diverse proteins such as receptor tyrosine phosphatases and neural cell adhesion molecules. This protein tyrosine kinase called ark (adhesion-related kinase) is likely to represent a new class of receptor tyrosine kinase. Ark mRNA appears to be expressed in most cell lines and adult tissues examined except those of hematopoietic lineage. It is undetectable in undifferentiated teratocarcinoma cells, F9 and N Tera 2.

We studied the different potentials of a secreted and a nonsecreted member of the fibroblast growth factor (FGF) family to induce autocrine growth stimulation in human adrenal cortex carcinoma cells (SW-13). These epithelial cells express basic FGF (bFGF) cell surface receptors, and picomolar concentrations of bFGF suffice to induce anchorage-independent growth. The requirement for exogenously added bFGF contrasts with the intracellular storage of biologically active bFGF in SW-13 cells greater than 10,000-fold in excess of the concentration needed to stimulate anchorage independent growth. To study whether the expression of a secreted FGF would alter the growth phenotype of these cells, we transfected them with an expression vector coding for the Kaposi-fgf (K-fgf) oncogene. In contrast to controls, K-fgf-transfected cells secrete significant amounts of biologically active K-fgf protein into the growth media, show up to 50-fold increased colony formation in soft agar, and grow into rapidly progressing, highly vascularized tumors in athymic nude mice. A reversible inhibition of the autocrine growth stimulation in vitro is brought about by the polyanionic compound suramin. We conclude that FGF has to be released from SW-13 cells to function fully as a growth stimulator in vitro and in vivo.

Resume On presente une approche experimentale des phenomenes de transfert de chaleur et de masse a l'interieur du bois et de leur couplage avec les conditions externes lors d'un sechage par convection forcee a haute temperature. Les conditions aerothermiques etudiees vitesse et temperature de l'ecoulement sont respectivement comprises entre 6 et 19 m s−1 et 150 et 190°C. Les courbes de sechage, les evolutions spatio-temporelles de l'humidite et de la temperatures locales, ainsi que les variations de la pression en phase gazeuse dans le bois sont analysees. Le mecanisme de migration de l'humidite propose, justifie par un calcul approche, est du type du schema classique ‘a trois phases ’ couramment admis pour le sechage convectif d'un corps poreux hygroscopique mais comporte des aspects originaux lies a la nature du materiau et au niveau de temperature. En particulier, on met en evidence pendant la deuxieme phase un mouvement de l'eau libre, exclusivement longitudinal, sous l'effet du gradient de pression totale en phase gazeuse.

Resume On etudie par voie experimentale l'influence du pas longitudinal et du pas transversal sur le transfert convectif du cylindre en deuxieme ligne dans une disposition de trois cylindres en quinconce, a nombre de Reynolds modere. L'etude dynamique, fondee sur l'analyse du gradient parietal de vitesse et de son taux de fluctuation montre l'influence des parametres geometriques sur les differentes zones caracteristiques, couche limite laminaire, point de decollement, zone herniaire et tourbillon principal. L'etude du transfert thermique en ecoulement d'air charge de gouttelettes d'eau met en evidence les mecanismes modifiant la repartition de nombre de Nusselt local par rapport au cylindre seul. Il apparait une disposition optimale pour laquelle la combinaison des differents effets conduit au transfert maximum. Une correlation sur le nombre de Nusselt est proposee dans cette disposition.

We have examined the expression of chimeric plasmids containing coding sequences for the herpes simplex virus thymidine kinase (tk) gene or the Tn5 gene for neomycin resistance (neo) linked to the late promoter of polyoma DNA. Although polyoma late genes are generally not expressed in transformed cells containing only integrated viral DNA molecules, rat tk- or wild-type cells transfected with the tk- or neo-containing plasmids were capable of growing in medium containing either hypoxanthine-aminopterin-thymidine or G418, respectively, under conditions nonpermissive for extrachromosomal DNA replication, indicating that the tk or neo genes were fully expressed. Moreover, cells were capable of growth in either hypoxanthine-aminopterin-thymidine or G418, even in the absence of direct selection for this activity. Northern analysis indicated steady-state levels of tk or neo transcripts that approximated the levels of polyoma early transcripts. S1 analysis showed that these transcripts initiated within the late promoter of polyoma and that their 5' ends mapped at positions similar or identical to those utilized during late lytic infection. The effect of substitution of polyadenylation signals was examined. Although plasmids containing the polyoma early polyadenylation signal were more efficient in conferring to cells a stable G418-resistant phenotype than similar constructions using the late signal, both signals were found to be effectively utilized. This indicates that the inability to detect late transcripts in polyoma-transformed cells in the absence of free viral DNA production is not an effect of inefficient mRNA cleavage or polyadenylation. Our results suggest that late gene expression in integrated polyoma genomes is not regulated at the level of message initiation but, most likely, through posttranscriptional events.

Resume On presente une etude experimentale du transfert evapo-convectif entre un cylindre chauffe et un ecoulement d'air charge de gouttelettes d'eau, en regime permanent et en regime pulse. En regime permanent, on precise les conclusions generales de l'etude bibliographique, en etablissant des correlations simples liant le transfert local sur la face amont du cylindre et le transfert global au nombre de Reynolds et au taux de chargement de l'ecoulement incident. A partir d'un modele d'ecoulement autour du cylindre precedemment etabli, on propose une interpretation physique des phenomenes observes et une modelisation du transfert sur la face aval. En regime pulse, on met en evidence les gains relatifs de transfert obtenus par effet de taux et de frequence de pulsation selon la valeur du taux de chargement, et on montre que ces resultats peuvent s'expliquer a partir de l'action des pulsations sur la dynamique du sillage.

The frequent occurrence of Kaposi's sarcoma (KS) in association with the acquired immune deficiency syndrome (AIDS) could be due to the fact that the etiological agent of this tumor is the same retrovirus causing AIDS, to another oncogenic virus frequently found in AIDS patients, or to the unmasking of the tumorigenic potential of KS cells by immunosuppression. We have therefore investigated the presence of DNA sequences homologous to the AIDS retrovirus, cytomegalovirus (CMV), and hepatitis B virus in 13 KS necropsies and biopsies from AIDS patients. All KS DNA samples were negative for AIDS retrovirus or hepatitis B DNA sequences. Two DNAs from necropsies contained CMV DNA, but the data suggested the presence of replicating CMV DNA due to generalized infection. We have also studied cell cultures derived from KS skin biopsies of AIDS patients. These cultures had a short lifetime in vitro and expressed some markers of endothelial cells. The cells were not tumorigenic in nude mice but contained a number of chromosomal rearrangements which were often monoclonal within the same culture. However, these abnormalities were different from culture to culture and even in cultures from the same biopsy. The presence of these chromosomal abnormalities seemed to correlate with the cell positivity for endothelial markers. Taken together these results indicate that neither the AIDS retrovirus, CMV, or hepatitis B virus is directly responsible for the altered growth of KS cells, that KS may be polyclonal even within the same lesion, and that KS cells have a tendency to karyotypic rearrangements.

Basic fibroblast growth factor is a potent mitogen for a variety of cell types and has been suggested to have transforming activity. To test this hypothesis, we have introduced a human bFGF cDNA into NIH 3T3 cells either by DNA transfection or by retrovirus infection. We have compared the properties of cell lines obtained with cells prepared similarly but expressing the hst/K-fgf growth factor. While bFGF does not contain an amino terminal signal sequence and is not secreted from cells in which it is synthesized, hst/K-fgf does contain a signal sequence and is secreted from cells. Our results show that the transformed phenotype correlates directly with the level of bFGF expression, since all transformed clones expressed high levels of bFGF, while nontransformed clones expressed comparatively low levels of bFGF. In contrast, even low levels of hst/K-fgf expression resulted in a transformed phenotype. These results suggest that bFGF is an inefficient transforming protein and that this may relate to its lack of secretion.

Fifty consecutive patients having had cardiac catheterisation for coronary artery disease also underwent testing by three non-invasive methods commonly employed for assessment of left ventricular function. These included the first pass radionuclide ejection fraction, fractional shortening of the M-mode echocardiographic left ventricular internal dimension, and pre-ejection period/left ventricular ejection time ratio derived from systolic time intervals (PEP/LVET). Linear correlations of these non-invasive measures with cineangiographic ejection fractions were calculated. The first pass radionuclide ejection fraction correlated best. Echocardiograms and systolic time intervals proved less versatile since 11 of 50 echocardiograms were technically not suitable for measurement and 11 of 50 systolic time intervals could not be used because of left ventricular conduction delays. Overall, radionuclide ventriculography proved to be the most accurate and practical of these non-invasive techniques in evaluating left ventricular function in this group of patients with coronary artery disease.

To define the relationship between simian virus 40 (SV40)-specific T-antigen and cell growth and to look for regulatory mechanisms that might control T-antigen synthesis in transformed cells, we studied the expression of T-antigen and the viral transcription in SV40-transformed cells that were exponentially growing or arrested in the G1-phase of the cell cycle. We took advantage of the behavior of two lines of SV40-transformed mouse 3T3 cells (ts SV3T3), which, although transformed by wild-type SV40, are temperature sensitive for the expression of the transformed phenotype. At 32 degrees C, ts SV3T3 cells behave like standard transformants, whereas at 39 degrees C, they become arrested in G1 after reaching saturatio n density or under serum starvation. At 32 degrees C or growing at 39 degrees C, ts SV3T3 were 100% T-antigen positive and contained virus-specific mRNA. However, after G1 arrest at 39 degrees C, most of the cells became T-antigen negative. This seems to be caused by a lack of transcription of the integrated viral DNA, since these cells contain no appreciable amounts of SV40-specific RNA. Induction of proliferation in resting, T-antigen-negative ts SV3T3 cultures results in the reappearance of T-antigen a few hours before the cells enter DNA synthesis. These results suggest that transcription of the viral genome and T-antigen expression in SV40-transformed cells is subjected to a cell cycle control.

The frequency of sister chromatid exchange (SCE) was determined in rat fibroblasts transformed by wild-type polyoma virus or by a mutant temperature sensitive for viral large tumor antigen function (ts-a). Elevated SCE frequencies were observed in two wild-type transformed cell lines growing at 37 degrees and in four ts-a-transformed lines upon growth at the permissive temperature for large viral tumor antigen (33 degrees). The increase in SCE frequency in ts-a-transformed cells at 33 degrees was reversed by growth at 39 degrees (nonpermissive for T-antigen function). An increase in SCE at 33 degrees was not observed in untransformed cells or in a ts-a-transformed cell line which makes a defective large viral tumor antigen. These results suggest that large viral tumor antigen can induce SCEs. Since large viral tumor antigen is also responsible for amplification of integrated viral DNA sequences (4), we tried to correlate this phenomenon with the increased SCE frequency. However, increasing SCE artificially by growing cells in the presence of 12-O-tetradecanoylphorbol-13-acetate did not result in amplification of integrated viral DNA in the absence of large viral tumor antigen function. Thus, there is no simple causal relationship between increased SCE and amplification.

Polyoma virus (Py) large T-Antigen (LT) can promote the amplification of viral genomes integrated in the chromosomal DNA of rat fibroblasts, and this phenomenon requires the interaction of the LT protein with the viral origin of DNA replication. To compare the rate and the modality of selectable amplification events promoted by the Py LT with cellular-driven events, we constructed a double expression vector containing a murine dihydrofolate reductase (dhfr) cDNA and the bacterial chloramphenicol acetyl transferase (cat) gene controlled by the viral regulatory region. The plasmid was introduced into a rat cell line constitutively producing a temperature sensitive LT (cl 2), and clones were selected in low concentration of methotrexate (MTX). Three cl 2 transformants and one control cell line lacking LT were propagated at temperatures permissive (33 degrees C) and non permissive (39 degrees C) for LT function and, subsequently, challenged in one step with high MTX dosage at 39 degrees C. While the control line produced the same number of colonies irrespective of the temperature of propagation, the three LT positive lines yielded between 2 and greater than 100 times more colonies following propagation at permissive temperature, indicating that the presence of Py LT considerably increased the rate of amplification of integrated sequences linked to the viral origin of replication. In all cases the amplification event involved the exogenous and not the endogenous dhfr gene, and overexpression of the cat gene occurred as a result of co-amplification with the selectable dhfr sequences. Analysis of the structure of the amplified domain in the various resistant derivatives revealed that, in the presence of the viral protein, amplification occurred within the boundaries of the primary plasmid insert. In the absence of a functional LT protein, amplification both internal or involving adjacent host DNA were observed.

The protein encoded in a novel human oncogene isolated by transfection of Kaposi's sarcoma DNA is a growth factor with significant homology to basic and acidic FGFs. The genomic structure of this oncogene (designated K-FGF), as originally isolated, carried DNA rearrangements upstream and downstream of the coding region. The normally discontinuous sequence upstream of the K-FGF coding region derived from the 3' end of the c-fms gene and thus originated from human chromosome 5. In order to determine the normal chromosomal location of the K-FGF gene and of the DNA sequences adjacent to its 3' end, we have correlated the presence of these sequences with retention of specific human chromosome regions in rodent-human somatic cell hybrids. These experiments mapped the K-FGF gene to human chromosome region 11q13----11q23, and in situ hybridization localized it more precisely to region 11q13 near int-2, which also belongs to the FGF family. The sequence downstream of the gene in transfectants and discontinuous with K-FGF in normal human DNA derives from chromosome region 12p12----12q13, possibly near the int-1 locus.

A procedure has been devised to isolate 3T3 mouse fibroblasts transformed by simian virus 40 (SV40) that express their transformed phenotype at low (32 degrees C) but not at high (39 degrees C) temperature. Three parameters typical of malignant growth in vitro: (a) high saturation density in culture, (b) ability to form colonies on monolayers of normal 3T3 cells, and (c) lack of contact inhibition of DNA synthesis, are temperature sensitive. These phenotypic changes are fully reversible. The serum requirement for growth appears to be largely unchanged by temperature. These cells seem to owe their behavior to a cellular, rather than to a viral, alteration since after fusion of the temperature-sensitive transformed cells with permissive monkey cells, a procedure that leads to rescue (i.e., multiplication of the virus), wild-type SV40 virus is produced.

TODAY poliomyelitis in the United States results either from rare epidemics in unvaccinated, closed populations or from complications of the trivalent oral polio vaccine. The clinical features in an unimmunized patient, the history of contact to trivalent oral polio vaccine, and the serologic and virologic data document this case as vaccine-associated poliomyelitis in a contact. Report of a Case A 30-year-old married, New England farmer was in excellent health until two days prior to admission when he awoke with a frontal and bioccipital headache unrelieved by aspirin. On the day prior to admission, he noted right leg weakness but proceeded to labor strenuously in the hayfields. He was seen at his local hospital, where examination showed proximal right lower-extremity weakness. His right ankle jerk was absent, and his right knee jerk diminished. Right plantar reflex was equivocal. The left lower extremity had normal strength and reflexes. There were no sensory

Purpose of the study To confirm in our cohort of patients the correlation between hyperbilirubinaemia (defined as unconjugated bilirubin >2 mg/dL and/or total bilirubin >2.5 mg/dL) and elevated atazanavir (ATV) trough levels (i.e. >750 ng/ mL), and to assess the efficacy of a therapeutic drug monitoring (TDM)-guided ATV dose reduction in order to improve the clinical impact of this adverse event.

Activating mutations in fibroblast growth factor receptor 2 (FGFR2) cause several craniosynostosis syndromes by affecting the proliferation and differentiation of osteoblasts, which form the calvarial bones. Osteoblasts respond to FGF with increased proliferation and inhibition of differentiation. We analyzed the gene expression profiles of osteoblasts expressing FGFR2 activating mutations (C342Y or S252W) and found a striking down-regulation of the expression of many Wnt target genes and a concomitant induction of the transcription factor Sox2. Most of these changes could be reproduced by treatment of osteoblasts with exogenous FGF. Wnt signals promote osteoblast function and regulate bone mass. Sox2 is expressed in calvarial osteoblasts in vivo and we show that constitutive expression of Sox2 inhibits osteoblast differentiation and causes down-regulation of the expression of numerous Wnt target genes. Sox2 associates with β-catenin in osteoblasts and can inhibit the activity of a Wnt responsive reporter plasmid through its COOH-terminal domain. Our results indicate that FGF signaling could control many aspects of osteoblast differentiation through induction of Sox2 and regulation of the Wnt–β-catenin pathway.

Fibroblast growth factors (FGFs) are key regulators of several developmental processes in which cell fate and differentiation to various tissue lineages are determined. The importance of the proper spatial and temporal regulation of FGF signals is evident from human and mouse genetic studies which show that mutations leading to the dysregulation of FGF signals cause a variety of developmental disorders including dominant skeletal diseases and cancer. The FGF ligands signal via a family of receptor tyrosine kinases and, depending on the cell type or stage of maturation, produce diverse biological responses that include proliferation, growth arrest, differentiation or apoptosis. A central issue in FGF biology is to understand how these diverse cellular responses are determined and how similar signaling inputs can generate distinct patterns of gene expression that govern the specificity of the cellular response. In this review we draw upon studies from the past fifteen years and attempt to construct a molecular picture of the different levels of regulation by which such specific cellular responses could be achieved by FGF signals. We discuss whether specificity could lie in the nature of the ligand, the particular receptor, the signal transduction pathways utilized, or the transcriptional regulation of specific genes. Finally, we also discuss how the interplay of FGF signals with other signaling systems could contribute to the cellular response. In particular we focus on the interaction with the Wnt pathway since FGF/Wnt cross-talk is emerging as an important nexus in regulating a variety of biological processes.