Evidence for the subsynaptic zone as a preferential site for CHRN recycling at neuromuscular junctions

Vertebrate skeletal muscle contraction is mediated by nicotinic acetylcholine receptors (CHRN). Endocytosis and recycling of CHRN regulate their proper abundance at nerve-muscle synapses, i.e. neuromuscular junctions. Recent work showed that RAB5 is essential for CHRN endocytosis. Here, using in vivo-imaging of endocytosed CHRN and RAB-GFP fusion proteins, we deliver evidence for differential effects of RAB5-GFP, RAB4-GFP, and RAB11-GFP on CHRN endocytosis. Furthermore, while newly endocytosed CHRN colocalized with RAB5-GFP over large stretches of muscle fibers, RAB4-GFP and RAB11-GFP colocalized with endocytosed CHRN almost exclusively at neuromuscular junctions. In agreement with previous findings, this data suggests the existence of a specialized subsynaptic zone that is particularly relevant for CHRN recycling.

[Can we transfer the mechanisms of the generics market to biosimilars?]

Personalized medicines such as biologics and their generic equivalents, biosimilars, are pouring onto the pharmaceutical markets. Data of 16 private health insurance companies were used to describe the market shares of selected biosimilars available in 2014 and 2015. The purpose of this study focuses on the question of whether market access of biosimilars will lead to a price competition of the expense of innovation competition. The results show that prescriptions of biosimilars made up 37% of total prescriptions in 2015 compared to 35% in 2014, and that their share of prescription costs went up from 21% to 23% in the same period. Price competition similar to that found in the generic markets has been established for erythropoietin and filgrastim. The same has not been observed for follitropin alfa and somatropin due to the limited number of competitors and products available at this stage. No definitive conclusions can be drown from the results at this stage. Time will tell whether it will be possible for physicians and individuals with private health insurance to fully leverage the savings potential of biosimilars while safeguarding patient safety.

Progress of endocytic CHRN to autophagic degradation is regulated by RAB5-GTPase and T145 phosphorylation of SH3GLB1 at mouse neuromuscular junctions in vivo

Endocytosed nicotinic acetylcholine receptors (CHRN) are degraded via macroautophagy/autophagy during atrophic conditions and are accompanied by the autophagic regulator protein SH3GLB1. The present study addressed the functional role of SH3GLB1 on CHRN trafficking and its implementation. We found an augmented ratio of total SH3GLB1 to threonine-145 phosphorylated SH3GLB1 (SH3GLB1:p-SH3GLB1) under conditions of increased CHRN vesicle numbers. Overexpression of T145 phosphomimetic (T145E) and phosphodeficient (T145A) mutants of SH3GLB1, was found to either slow down or augment the processing of endocytic CHRN vesicles, respectively. Co-expression of the early endosomal orchestrator RAB5 largely rescued the slow processing of endocytic CHRN vesicles induced by T145E. SH3GLB1 phosphomutants did not modulate the expression or colocalization of RAB5 with CHRN vesicles, but instead altered the expression of RAB5 activity regulators. In summary, these findings suggest that SH3GLB1 controls CHRN endocytic trafficking in a phosphorylation- and RAB5-dependent manner at steps upstream of autophagosome formation.

The impact of autophagy on peripheral synapses in health and disease

Alterations of autophagy have been linked to several peripheral nervous system diseases, such as amyotrophic lateral sclerosis and Charcot-Marie-Tooth disease. Modulation of autophagy by metabolic or pharmacological interventions has been increasingly recognized as a strategy to fight many of these disorders. Cellular processes that are aberrant in case of impaired autophagy and that might lead to these diseases belong to three different categories: (1) clearing of protein aggregates, (2) regulation of vesicle and cargo turnover, and (3) disposal of damaged mitochondria. This review summarizes the present literature that addresses both, the impact and mechanisms of autophagy on the health of the peripheral nervous system and treatment proposals for human disorders associated with impaired autophagy.

[The relevance of multiple sclerosis drugs in private health insurance (PHI)]

The development of expenses and prescriptions in the pharmacotherapy for multiple sclerosis (MS) is examined on the basis of prescription data of 14 PHI firms. The drugs for the treatment of MS are among the most top-selling drugs in the PHI. From 2007 to 2012, the expenses increase 2.33-fold. The main cause is the increas of the prescription figures. In 2012, about 8,400 privately insured persons receive an MS drug. The prevalence of MS is 2.3 times higher in women than in men Impro ved diagnostic possibilities and expensive new drugs will lead to a dynamic cost de velopment in the next years.

[Prevalence of HIV treatment in PHI]

The importance of HIV in PHI is examined on the basis of the "AIDS statistics" of the Association of PHI and pharmaceutical data from PHI. The observation period is from 2007 to 2011. We define a HIV case if a private insured person has submitted at least one HIV-related invoice (e.g., an antiretroviral drug) for reimbursement during the observation period. In 2011, 7,624 people in PHI received HIV therapy, that is 32% (+1888) more than in 2007. The number of new HIV cases in 2011 was 673, and thus 12% (-92) lower than in 2007. The proportion of people receiving antiretroviral therapy in PHI is higher than in the general population in Germany. HIV infections occur in all age groups, but peaks in the age group 41 to 50 years old. Men are affected more than women. In contrast, the number of HIV cases among 11- to 15-year-old girls is higher compared to boys of the same age.

Role of autophagy, SQSTM1, SH3GLB1, and TRIM63 in the turnover of nicotinic acetylcholine receptors

Removal of ubiquitinated targets by autophagosomes can be mediated by receptor molecules, like SQSTM1, in a mechanism referred to as selective autophagy. While cytoplasmic protein aggregates, mitochondria, and bacteria are the best-known targets of selective autophagy, their role in the turnover of membrane receptors is scarce. We here showed that fasting-induced wasting of skeletal muscle involves remodeling of the neuromuscular junction (NMJ) by increasing the turnover of muscle-type CHRN (cholinergic receptor, nicotinic/nicotinic acetylcholine receptor) in a TRIM63-dependent manner. Notably, this process implied enhanced production of endo/lysosomal carriers of CHRN, which also contained the membrane remodeler SH3GLB1, the E3 ubiquitin ligase, TRIM63, and the selective autophagy receptor SQSTM1. Furthermore, these vesicles were surrounded by the autophagic marker MAP1LC3A in an ATG7-dependent fashion, and some of them were also positive for the lysosomal marker, LAMP1. While the amount of vesicles containing endocytosed CHRN strongly augmented in the absence of ATG7 as well as upon denervation as a model for long-term atrophy, denervation-induced increase in autophagic CHRN vesicles was completely blunted in the absence of TRIM63. On a similar note, in trim63(-/-) mice denervation-induced upregulation of SQSTM1 and LC3-II was abolished and endogenous SQSTM1 did not colocalize with CHRN vesicles as it did in the wild type. SQSTM1 and LC3-II coprecipitated with surface-labeled/endocytosed CHRN and SQSTM1 overexpression significantly induced CHRN vesicle formation. Taken together, our data suggested that selective autophagy regulates the basal and atrophy-induced turnover of the pentameric transmembrane protein, CHRN, and that TRIM63, together with SH3GLB1 and SQSTM1 regulate this process.

[Increases in pharmaceutical expenditures of PHI by monoclonal antibodies]

The dynamics of one of the most innovative segments of health care and its impact on pharmaceutical expenditure of private health insurance (PHI) is examined on the basis of drug prescription data from private health insurance companies. The study shows that the increase in pharmaceutical expenditure can be explained partly by the new treatment possibilities available with monoclonal antibodies. The per capita expenditure on drugs with monoclonal antibodies increased by 255% from 2006 to 2010 in private health insurance, while the corresponding expenditure of all pharmaceuticals has risen by only 19% in the same period. In the coming years, growth on this scale will be a challenge for all payers in the health system.

[The pharmaceutical cost of elderly people in private health insurance]

In this paper the author analyses the prescription of pharmaceuticals for elderly private insured persons. Data from eight firms form the basis of the survey. The main focus lies in the analysis of the expenditure per capita and the distribution of the pharmaceuticals costs. It will illustrate that costs for elderly private insured persons will have a great impact on the expenditure for the private health insurance companies in the coming years.

EchoComTEE - a simulator for transoesophageal echocardiography

Transoesophageal echocardiography (TOE) requires extensive hands-on training, and it is for this purpose we have designed EchoComTEE, a simulator for TOE. It consists of a manikin and dummy probe; according to the position of the dummy probe (tracked by an electromagnetic sensor), two-dimensional (2D) images are calculated from three-dimensional (3D) data sets. Echocardiographic images are presented side-by-side with a virtual scene consisting of a 3D heart, probe tip and image plane. In this way the trainee is provided with visual feed-back of the relationship between echocardiogram and image plane position. We evaluated the simulator using a standardised questionnaire. Twenty-five experts and 31 novice users participated in the study. Most experts graded the simulator as realistic and all recommended its use for training. Most novice users felt the simulator supported spatial orientation during TOE and, as anaesthetists often do not have training in transthoracic echocardiography, in this group the TOE simulator might be particularly useful.

Moderate Versus Deep Hypothermia for Arterial Switch Operation

BACKGROUND

We evaluated the impact of moderate versus deep intraoperative hypothermia on postoperative morbidity in patients receiving a standard arterial switch operation (ASO).

METHODS

71 newborns underwent ASO from 9/98 onwards. Patients were operated using moderate hypothermia (M, 24 degrees C to 30 degrees C, n=21) or deep hypothermia (D, 16-22 degrees C, n=50). Mean patient age was 9.5 (M) versus 10 (D) days, body weight 3.6+/-0.7 (M) versus 3.8+/-0.9 kg (D), P=n. s. Coronary anatomy was complex in 9.5% (M) versus 16% (D) of patients; additional VSD was present in 23.8 (M) versus 38% (D) of the patients, respectively. Mean follow-up is 2.3+/-1.6 years.

RESULTS

Intraoperative rectal temperature was 25+/-2 degrees C (M) and 19+/-2 degrees C (D). Cross-clamping time was 95+/-24 (M) versus 108+/-31 min (D), P=n. s. Conventional ultrafiltration was performed at 114+/-46 (M) versus 129+/-69 ml/kg (D), P=n. s. One patient (D) with complex anatomy suffered myocardial ischemia required ECMO support and died. In-hospital mortality was 1.4%. All other patients were safely weaned from extracorporeal circulation with moderate inotropic support. Secondary chest closure was performed in 33% (M) versus 54 % (D) of the patients. Patients were extubated after 7.4 (M) versus 6 (D) days. There was no renal failure and no other serious complications.

CONCLUSIONS

ASO can be safely performed using moderate hypothermia, even with complex anatomy, leading to comparatively good results compared to a conventional approach.

Measles outbreak in the Provence-Alpes-Côte d'Azur region, France, January-July 2003

At the end of May 2003, the Marseilles Hospital Centre's virology laboratory informed the French public heath institute of 5 cases of confirmed measles among young adults living in Marseilles. An investigation was conducted, consulting different community and hospital health services, to determine the virus circulation in the Provence-Alpes-Côte d'Azur (PACA) region by the southern interregional epidemiological cell. The investigation identified 259 cases: 183 clinical, 74 serologically confirmed and 2 epidemiologically linked cases. The first cases were identified during the first six months of 2003, with a peak in April. This outbreak of measles in the PACA region was favoured by poor vaccination coverage, which created groups of susceptible population. The real number of cases was probably higher than the number identified. This investigation has outlined the limitations of the measles surveillance system in France: the sentinel network had not detected any case for this period. France needs to reach the WHO objective of measles elimination by 2010 and the surveillance tools used must be those already used in the most countries that are furthest advanced in the elimination process. To reach this goal, the Direction Générale de la Santé has nominated a working group to be in charge of proposing a national plan to interrupt indigenous measles transmission in France.

Measles outbreak in the Provence - Alpes - Côte d’Azur region, France, January - July 2003

At the end of May 2003, the Marseilles Hospital Centre’s virology laboratory informed the French public heath institute of 5 cases of confirmed measles among young adults living in Marseilles. An investigation was conducted, consulting different community and hospital health services, to determine the virus circulation in the Provence-Alpes-Côte d’Azur (PACA) region by the southern interregional epidemiological cell. The investigation identified 259 cases: 183 clinical, 74 serologically confirmed and 2 epidemiologically linked cases. The first cases were identified during the first six months of 2003, with a peak in April. This outbreak of measles in the PACA region was favoured by poor vaccination coverage, which created groups of susceptible population. The real number of cases was probably higher than the number identified. This investigation has outlined the limitations of the measles surveillance system in France: the sentinel network had not detected any case for this period. France needs to reach the WHO objective of measles elimination by 2010 and the surveillance tools used must be those already used in the most countries that are furthest advanced in the elimination process. To reach this goal, the Direction Générale de la Santé has nominated a working group to be in charge of proposing a national plan to interrupt indigenous measles transmission in France.

Dendritic cells recruitment and in vivo priming of CD8+ CTL induced by a single topical or transepithelial immunization via the buccal mucosa with measles virus nucleoprotein

The buccal mucosa, a prototype of pluristratified mucosal epithelia, contains a network of directly accessible class II(+) epithelial dendritic cells (DC), similar to skin Langerhans cells. We showed that a single buccal immunization with measles virus nucleoprotein (NP), by either topical application onto or intradermal injection in the buccal mucosa, induced in vivo priming of protective class I-restricted specific CD8(+) CTL. Both routes of immunization with NP induced a rapid recruitment of DC into the mucosa, which peaked at 2 h and decreased by 24 h. Treatment of mice with Flt3 ligand resulted in an increased number of DC in the buccal mucosa and enhanced the frequency of IFN-gamma-producing NP-specific effectors and the NP-specific CTL response generated after buccal immunization with NP. Finally, NP-pulsed bone marrow-derived DC induced NP-specific IFN-gamma-producing cells upon adoptive transfer to naive mice. These data demonstrate that a viral protein delivered to DC of the buccal mucosa induces in vivo priming of protective anti-viral CD8(+) CTL.

Measles virus infects human dendritic cells and blocks their allostimulatory properties for CD4+ T cells

Measles causes a profound immune suppression which is responsible for the high morbidity and mortality induced by secondary infections. Dendritic cells (DC) are professional antigen-presenting cells required for initiation of primary immune responses. To determine whether infection of DC by measles virus (MV) may play a role in virus-induced suppression of cell-mediated immunity, we examined the ability of CD1a+ DC derived from cord blood CD34+ progenitors and Langerhans cells isolated from human epidermis to support MV replication. Here we show that both cultured CD1a+ DC and epidermal Langerhans cells can be infected in vitro by both vaccine and wild type strains of MV. DC infection with MV resulted within 24-48 h in cell-cell fusion, cell surface expression of hemagglutinin, and virus budding associated with production of infectious virus. MV infection of DC completely abrogated the ability of the cells to stimulate the proliferation of naive allogeneic CD4+ T cell as early as day 2 of mixed leukocyte reaction (MLR) (i.e., on day 4 of DC infection). Mannose receptor-mediated endocytosis and viability studies indicated that the loss of DC stimulatory function could not be attributed to the death or apoptosis of DC. This total loss of DC stimulatory function required viral replication in the DC since ultraviolet (UV)-inactivated MV or UV-treated supernatant from MV-infected DC did not alter the allostimulatory capacity of DC. As few as 10 MV- infected DC could block the stimulatory function of 10(4) uninfected DC. More importantly, MV-infected DC, in which production of infectious virus was blocked by UV treatment or paraformaldehyde fixation, actively suppressed allogeneic MLR upon transfer to uninfected DC-T-cultures. Thus, the mechanisms which contribute to the loss of the allostimulatory function of DC include both virus release and active suppression mediated by MV-infected DC, independent of virus production. These data suggest that carriage of MV by DC may facilitate virus spreading to secondary lymphoid organs and that MV replication in DC may play a central role in the general immune suppression observed during measles.

DNA immunization circumvents deficient induction of T helper type 1 and cytotoxic T lymphocyte responses in neonates and during early life

The relative deficiency of T helper type 1 (Th1) and cytotoxic T lymphocyte (CTL) responses in early life is associated with an increased susceptibility to infections by intracellular microorganisms. This is likely to reflect a preferential polarization of immature CD4 T cells toward a Th2 rather than a Th1 pattern upon immunization with conventional vaccines. In this report, it is shown that a single immunization within the first week of life with DNA plasmids encoding viral (measles virus hemagglutinin, Sendai virus nucleoprotein) or bacterial (C fragment of tetanus toxin) vaccine antigens can induce adult-like Th1 or mixed Th1/Th2 responses indicated by production of IgG2a vaccine-specific antibodies and preferential secretion of interferon-gamma (IFN-gamma) compared with interleukin (IL)-5 by antigen-specific T cells, as well as significant CTL responses. However, in spite of this potent Th1-driving capacity, subsequent DNA immunization was not capable of reverting the Th2-biased responses induced after early priming with a recombinant measles canarypox vector. Thus, DNA vaccination represents a novel strategy capable of inducing Th1 or mixed Th1/Th2 and CTL responses in neonates and early life, providing it is performed prior to exposure to Th2-driving conventional vaccine antigens.

Inhibition of HIV-1, HIV-2 and SIV envelope glycoprotein-mediated cell fusion by calmodulin

Calmodulin, an EF-hand protein, inhibited the fusion between CD4+ human cells and cells stably expressing HIV-1 envelope proteins. Fusion was also inhibited when HIV-1, HIV-2 or SIV envelope glycoproteins were expressed by vaccinia virus (VV) recombinants, but calmodulin did not inhibit syncytia formation induced by measles virus glycoproteins. Calmodulin also inhibited fusion induced by vPE17, a VV-recombinant expressing a truncated form of HIV-1gp160 which lacks the two known calmodulin-binding sites located in the cytoplasmic domain of gp41. The inhibitory activity was specific to calmodulin among the EF-hand proteins. These observations may be important in understanding the mechanism of retroviral envelope glycoprotein-mediated cell fusion. Several possible mechanisms of action are discussed.

Self-association of truncated forms of HIV-1 gp120

HIV-1 gp120 and truncated forms were expressed in HeLa T4 cells by vaccinia recombinant viruses. The truncated gp120 molecules consisted of N-terminal overlapping envelope proteins of 204, 287 and 393 amino acids respectively. Immunoprecipitation with specific monoclonal antibodies and SDS-PAGE analyses of HIV-1 gp120 revealed bands corresponding to low amounts of secreted and cell-bound stable dimers. In contrast, the truncated forms of gp120 expressed larger amounts of SDS-stable putative dimers and the amounts observed were inversely proportional to their size. The shortest gp120 mutant (204 aa) was found to be secreted almost exclusively as a dimer. The processing of gp120 and its truncated forms was further investigated in the presence of inhibitors of N-glycosylation. Monomers and dimers migrated on gels with the same relative changes, confirming that the protein with the higher molecular weight is a multimer of the smaller one. The putative dimeric form of the truncated gp120s could be stabilized by chemical cross-linking. Finally, the possible existence of an association domain in the N-terminal 204 amino acids (aa) of gp120 is discussed.

Mucosal and systemic immune responses to measles virus haemagglutinin in mice immunized with a recombinant vaccinia virus

The immune response to a vaccinia virus recombinant expressing the measles virus haemagglutinin (VV-HA) was compared after parenteral or mucosal immunizations in mice. Parenteral immunizations with 10(6) p.f.u. VV-HA induced HA-specific antibody-producing cells (IgG>IgA) and HA-specific class I-restricted cytotoxic T lymphocytes (CTL) in the spleen. In contrast, intranasal administrations of 10(6) p.f.u. of VV-HA induced HA-specific spot-forming cells in the spleen (IgG>IgA) and the lungs (IgA>IgG), and HA-specific CTL in the spleen. Co-immunization by the nasal route with VV-HA and cholera toxin enhanced HA-specific immune responses. Oral immunizations with 10(8) p.f.u. of VV-HA generated low numbers of HA-specific IgA-producing cells in the lamina propria of the gut, and a weak HA-specific CTL activity in the spleen and mesenteric lymph nodes. Oral co-immunization with VV-HA and cholera toxin greatly enhanced the level of HA-specific spot-forming cells in the lamina propria (IgA>IgG). Interestingly, intrajejunal immunizations with 10(8) p.f.u. VV-HA alone induced high levels of anti-HA IgG-producing cells in the spleen and anti-HA IgA-secreting cells in the lamina propria of the gut. These data show that (i) VV-HA by the nasal route is immunogenic and generates a measles-specific mucosal immune response in the lung, which represents the primary site of replication of measles virus and that (ii) VV-HA can also induce measles-specific immunity in the intestine provided that it is protected from degradation in the gastrointestinal tract, or that cholera toxin is used as an adjuvant.

[Dwarfism in pericentric inversion of the X-chromosome]

We report on a 9 2/12 year old girl with pericentric inversion of the X-chromosome. It was diagnosed accidentally by a chromosome-analysis led through because of small stature. She bears a strong phenotypic resemblance to her mother (normal chromosomes), carrier of the pericentric inversion however is the phenotypically normal father. The breakpoint of the X-chromosome not lying within the critical region suggests that the patient will neither suffer a gonadal dysfunction. Both short stature and phenotypic dysmorphic features have familial cause.

Characterization of a secreted form of measles virus haemagglutinin expressed from a vaccinia virus recombinant

The measles virus (MV) haemagglutinin (HA) is a class 2 glycoprotein by means of which the virus particle attaches to the host cell receptor. We have previously expressed this glycoprotein as a vaccinia recombinant virus and have shown that the HA glycoprotein synthesized is indistinguishable from that coded by MV. In the present study, we report that in RK13 cells a soluble form (sHA) of the HA is secreted into the medium. We show by SDS-PAGE and sucrose density gradient centrifugation that the sHA is a dimer and is smaller than the cell-associated form. Using a variety of inhibitors the production of sHA was shown to be a late event, probably occurring at the membrane; only fully glycosylated molecules were found in sHA. Finally, we demonstrate that sHA retains its antigenicity with conformation-dependent MAbs and its receptor recognition function. We conclude that sHA is a valuable tool for use in studies of the structure and function of the MV HA glycoprotein.

Color Doppler imaging of modified Blalock-Taussig shunts during infancy

To assess the role of color Doppler echocardiography in the early postoperative evaluation of patients with a Blalock-Taussig shunt we examined 13 consecutive infants who underwent insertion of either a modified right (6 patients) or a modified left (7 patients) Blalock-Taussig shunt (age range 7 days to 6 months, mean age 8 weeks). Examination of the patients in a high parasternal right or left long axis was able to determine patency of the shunt in 12 patients. In the remaining patient, who did not show flow in the shunt, complete occlusion of the shunt was confirmed by angiography. From subcostal views we were able to demonstrate patency of the shunt in 75% of the infants and in all patients younger than 4 weeks of age. In our experience color Doppler echocardiography is a highly reliable method for early postoperative evaluation of infants with a Blalock-Taussig shunt.

Color Doppler imaging of modified Blalock-Taussig shunts during infancy

To assess the role of color Doppler echocardiography in the early postoperative evaluation of patients with a Blalock-Taussig shunt we examined 13 consecutive infants who underwent insertion of either a modified right (6 patients) or a modified left (7 patients) Blalock-Taussig shunt (age range 7 days to 6 months, mean age 8 weeks). Examination of the patients in a high parasternal right or left long axis was able to determine patency of the shunt in 12 patients. In the remaining patient, who did not show flow in the shunt, complete occlusion of the shunt was confirmed by angiography. From subcostal views we were able to demonstrate patency of the shunt in 75% of the infants and in all patients younger than 4 weeks of age. In our experience color Doppler echocardiography is a highly reliable method for early postoperative evaluation of infants with a Blalock-Taussig shunt.

[Interventional treatment of pulmonary atresia with intact ventricular septum by high frequency perforation and balloon dilatation of the pulmonary valve]

Surgical treatment of neonates with pulmonary atresia and intact ventricular septum is associated with a high morbidity and mortality. During the last two years specific radiofrequency-catheters have been developed, which allow the interventional perforation and subsequent balloon dilatation of an atretic pulmonary valve during cardiac catheterization. We report our experience with this new interventional technique in two neonates. In the first case perforation and balloon dilatation of the atretic pulmonary valve was performed without a complication. In the second case the radiofrequency catheter perforated the right ventricular outflow tract. There was no pericardial tamponade and the patient underwent a surgical valvotomy the following day. In our experience radiofrequency-assisted balloon dilatation of the pulmonary valve is a possible alternative in the treatment of neonates with pulmonary atresia, intact ventricular septum and moderate hypoplasia of the right ventricle. Further experience will have to show, whether this new interventional technique can be generally recommended.

[Doppler echocardiography assessment of hemodynamic values and additional heart defects in atrial septal defects]

Due to the rapid progress in (Doppler-) echocardiography "one must question whether cardiac catheterisation remains a necessary prelude to cardiac surgery in atrial septal defects" (8). Although the estimation of the magnitude of the intracardiac shunt and the anatomical size of the defect ist possible by (Doppler-) echocardiography there remains the problem of associated disorders (e.g. anomalies of the pulmonary venous connection) which may not be detected by transthoracic echocardiography. In 25 children submitted to cardiac catheterisation studies in the period between 1990 and 1992, the anatomical size of an atrial septal defect was measured echocardiographically. The haemodynamic parameters Qp/Qs and Rp/Rs were employed to calculate the so-called effective resistance of the defect (Rd/Rs), which was derived from an electrical analogue and represents the ratio of the resistance of the defect (Rd) to the systemic vascular resistance (Rs). The echocardiographically measured anatomical size (expressed as the ratio of the area of the defect to the cross-sectional area of the ascending aorta) was related to the effective resistance of the defect. A significant (non-linear) correlation was found between Rd/Rs and the anatomical size of defect. Based on these data we developed a nomogram describing the relationship of the size of the defect to the haemodynamic parameters (Qp/Qs and Rp/Rs). If the data of a patient do not comply with this nomogram there is strong evidence of an additional cardiovascular malformation, necessitating further evaluation. A second cohort of four patients with associated defects (partial and total anomalous pulmonary venous connection and a corresponding sinus venosus defect) was clearly identified by the nomogram method.

Analysis of the human immunodeficiency virus type 1 envelope protein interaction with the CD4 host cell receptor

A secreted form of human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (gp160s), expressed in HeLa cells from a vaccinia virus recombinant was analysed by velocity-gradient centrifugation and chemical cross-linking. We showed that gp160s existed predominantly as a dimer, but higher forms corresponding to trimers and tetramers were also found. Soluble CD4 (sCD4) and native CD4 expressed by recombinant vaccinia viruses were analysed by sucrose-gradient sedimentation alone or after complexing with gp160s. The sCD4 sedimented in sucrose gradients as a monomer, whereas after solubilization the native CD4 was in a dimeric state. Both forms of CD4 were able to form complexes when incubated with gp160s. In the case of the sCD4, the M(r) corresponded to a (sCD4)2-(gp160s)2 complex, whereas with CD4 the complexes were of a greater order of magnitude. HIV gp120 was secreted into the medium in a monomeric state. With sCD4 it gave a one-to-one complex, whereas with the native CD4 high M(r) complexes were formed. The importance of the oligomeric state of the virus- and cell-receptor proteins are discussed regarding their avidities.

Measles virus hemagglutinin induces an Ld-restricted CD8+ cytotoxic T lymphocyte response to two specific epitopes

Balb/c mice (H-2d) immunized with a vaccinia virus recombinant expressing the measles virus hemagglutinin (MV HA) induced a strong CD8+ cytotoxic T lymphocyte (CTL) response which was Ld-restricted. With reference to the predictive motif for Ld-restricted epitopes, a number of nonameric peptides derived from the primary sequence of the MV HA were tested for their ability to be restricted to the CTLs by P815 cells. Two peptides corresponding to amino acids 343-351 and 544-552 of the HA primary sequence sensitized target cells for lysis by the HA-specific CTLs.

The role of N-glycosylation in cell fusion induced by a vaccinia recombinant virus expressing both measles virus glycoproteins

We have evaluated the effect of inhibitors of N-glycosylation on syncytia formation in HeLa cell infected by a recombinant vaccinia virus expressing the measles virus hemagglutinin (HA) and fusion (F) glycoproteins (VV-HA/F). Inhibitors which block glucose trimming of oligosaccharides side chains of glycoproteins (glucosidase inhibitors) prevented syncytium formation. On the other hand, inhibitors which block trimming of mannose residues (mannosidase inhibitors) did not prevent syncytium formation. The HA and F synthesized in the presence of either glucosidase or mannosidase inhibitors oligomerized and were transported to the cell surface. Concanavalin A, a mannose-specific lectin, inhibited syncytium formation. The inhibitors did not block the cleavage of the F protein, but in fact enhanced it. These studies demonstrate the importance of protein N-glycosylation in the process of membrane fusion and suggest that trimming of glucose residues and the presence of terminal mannose residues are required for VV-HA/F syncytium induction.

Establishment and characterisation of murine cells constitutively expressing the fusion, nucleoprotein and matrix proteins of measles virus

To advance our understanding of the immunobiology of measles virus (MV) infections, we have investigated the possibility of establishing cell lines constitutively expressing the individual MV antigens. In contrast to previously published studies, we show that it is possible to establish cell lines expressing high levels of fusion (F), nucleoprotein (NP) and matrix (M) MV proteins. Once cloned, the cell lines were stable with high levels of expression for more than six months. The size and cell distribution of the NP and F proteins were similar to those observed in MV- or vaccinia-MV recombinant-infected cells. In contrast, the distribution of the M protein, although being similar to that of MV-infected cells, differed from that of Vaccinia-M recombinant virus-infected cells. Preliminary results suggest that these cell lines will be useful tools for studying the contribution of individual MV antigens to the cell-mediated immune response to this virus.

Improved visualisation of a coronary artery fistula by the "laid-back" aortogram

The preoperative assessment of patients with a coronary artery fistula requires exact angiographic evaluation of the coronary artery anatomy. A technique of transvenous balloon occlusion angiography of the aorta is described. This can be applied easily in infants with a persisting foramen ovale. Combination of this technique with the so-called "laid-back" aortogram gave excellent visualisation of a fistula between the right coronary artery and the right ventricle. This technique is a major improvement in the angiographic assessment of infants with coronary artery abnormalities and normal cardiac connections.

[Treatment of acute pulmonary hemorrhage in a patient with pulmonary atresia and ventricular septal defect by coil embolization of a systemico-pulmonary collateral artery]

Pulmonary hemorrhage due to rupture of pulmonary arteries causes significant morbidity and mortality in the natural history of older patients with pulmonary atresia and ventricular septal defect. The only therapeutical option for patients with persisting pulmonary hemorrhage was surgical resection of the involved pulmonary segments. In this case report we describe the successful termination of an acute pulmonary hemorrhage in a 9-year-old patient by coil-embolization of a systemicopulmonary collateral artery, which provided additional blood supply to the left upper-lobe segments. The hemorrhage ceased within 24 h and has not recurred during a follow-up period of 7 months. In our opinion, the success of the embolization can be attributed to a reduction of the perfusion pressure and a normalization of the arterial blood flow in the affected lung segments.

[Echocardiographic diagnosis of congenital diverticuli of the right and left ventricle]

A congenital diverticulum of the ventricle is a very rare cardiac lesion which is almost always associated with additional cardiovascular anomalies. In the majority of cases a diverticulum of the heart has been diagnosed during cardiac catheterization for evaluation of additional cardiovascular anomalies. We report noninvasive echocardiographic diagnosis of a congenital cardiac diverticulum in two patients. Noninvasive imaging of the diverticulum facilities planning of cardiac catheterization, angiographic imaging and surgical treatment of this rare anomaly.

Total cavopulmonary anastomosis: selection criteria related to postoperative results

In this study we review our experience with total cavopulmonary anastomosis (modified Fontan procedure) which was performed in 31 patients. One patient died from postoperative cardiac low-output syndrome, the other died from a neurological complication (early mortality 6.5%). During a mean follow-up period of 15 months there was no late mortality. Preoperative assessment showed that one, two, or three of the Choussat criteria (defining the ideal Fontan candidate) were not fulfilled by 39%, 16% and 6% of our patients. In the 2 patients who died 2 and 3 of those criteria were not fulfilled. Poor outcome could not be predicted based on assessment of the pulmonary artery size (expressed as the McGoon-ratio or the Nakata-index) alone. In order to assess the relationship of pulmonary artery size and pulmonary arteriolar resistance (PVR) as a predictor of outcome, we introduced two new indices (McGoon-ratio/PVR and Nakata-index/PVR). The patient who died from poor postoperative hemodynamics had the lowest values of all patients. Among the 29 survivors we did not observe significant acquired postoperative arrhythmias. In our experience the total cavopulmonary anastomosis can be performed with a low mortality and good postoperative results. Patients who do not fulfill at least 8 of the Choussat criteria and children with a low ratio of pulmonary artery size to PVR are high-risk patients. In these children we recommend either a bidirectional Glenn anastomosis as a first-step procedure or a total cavopulmonary anastomosis with a fenestration of the intraatrial tunnel.

A leucine zipper structure present in the measles virus fusion protein is not required for its tetramerization but is essential for fusion

The biological role of a leucine zipper motif present in the measles virus fusion (F) protein has been investigated. This motif is present in all paramyxovirus F proteins, all coronavirus spike proteins and many if not all retrovirus envelope proteins. By analogy to its role in certain transcription factors, it has been suggested that the motif may be responsible for the oligomerization of these viral membrane proteins. In this study, one, two or four heptadic leucines in the motif were substituted using site-directed mutagenesis. We found that fusion is prevented when all four heptadic leucines present in the motif are mutated whereas cellular transport and the oligomeric state of the F protein are unaffected.

Characterization of an R-binding site mediating the R-induced activation of the Epstein-Barr virus BMLF1 promoter

In cells latently infected with Epstein-Barr virus, the switch from latency to productive infection is linked to the expression of two Epstein-Barr virus transcription factors called EB1 and R. R is an enhancer factor, and an R-responsive element (RRE) has been identified in the BMLF1 promoter. In this study, we have used bidirectional deletion mutagenesis to delineate the BMLF1 RRE (RRE-M) to a 44-bp sequence. We also show that R expressed from a recombinant vaccinia virus protects RRE-M against digestion by DNase I. Using mobility shift assays and dimethyl sulfate interferences, we have characterized the contact points between in vitro-translated R and the DNA. R binds in vitro to one site by simultaneously contacting two sequences within the site, which are separated by 8 bp: 5'-catGTCCCtctatcatGGCGCagac-3'. Site-directed mutagenesis of this sequence completely impaired the binding of R in vitro and rendered the BMLF1 promoter nonresponsive to R. The results suggest that the R-inducible BMLF1 enhancer is composed of a single R-binding site, called RRE-M.