L929 cells infected with temperature sensitive mutants of vesicular stomatitis virus: virus replication is necessary for induction of changes in membrane permeability

Infection of L929 murine cells with vesicular stomatitis virus (VSV) results in inhibition of host protein synthesis and appearance of membrane alterations at a time when cells are still actively engaged in viral protein synthesis. VSV temperature-sensitive (ts) mutants have been used to explore the role(s) played by the virus-coded proteins in the genesis of these effects. Cells were infected with each of five ts mutants representing the known complementation groups of VSV Indiana serotype, and incubated at permissive (32 degrees C) and non-permissive temperatures (39 degrees C). Protein synthesis in the presence and absence of Hygromycin B (Hyg. B) was analyzed during virus infection via incorporation of 35S-methionine in acid-precipitable material and SDS-polyacrylamide gel electrophoresis. Data indicate that mutants belonging to groups I (L protein), II (NS protein) and IV (N protein) do not inhibit host protein synthesis and do not induce any membrane changes when grown at the non-permissive temperature. Mutants of group III (M protein) and V (G protein), instead, do inhibit cell protein synthesis and induce membrane changes also when grown at the non-permissive temperature; this suggests that these effects do not correlate with the biological activity of these proteins and their interaction with the cellular membrane. On the other hand, mutants exhibiting defective steps of nucleocapsid replication are apparently unable to induce these effects once more suggesting that virus replication per se is essential, as also indirectly shown by experiments employing cycloheximide to mimic shut-off.

[Therapy of non-metastatic Ewing's sarcoma (pelvis excluded). Results obtained in 48 cases combining local therapy (radiation and/or surgical) and adjuvant chemotherapy with vincristine, adriamycin, dactinomycin and cyclophosphamide]

Combined therapy was used on a consecutive series of 48 patients with extrapelvic Ewing's sarcoma at the Rizzoli Orthopaedic Institute. The adjuvant chemotherapy protocol (VCR, ADM, D-ACT, EDX) was identical in all patients whereas local treatment consisted of amputation, resection and radiation treatment or radiation alone. At a mean follow-up of 58 months (39-78) 30 patients (60%) were free of the disease. This is a significantly higher percentage than that obtained in the same period with adjuvant chemotherapy using only 3 drugs (VCR, ADM, EDX). As far as the type of local treatment is concerned, the percentage of local recurrences and metastases was lower when the primary lesion was treated with surgery or surgery combined with radiotherapy, rather than radiation treatment alone. These suggest that if associated with radiation treatment and chemotherapy, surgery can play an important role that should be considered in the treatment of extrapelvic Ewing's sarcoma.

Reduced maturation of Friend virus in adhesive mutants of Friend leukemia cells

The replication of Friend Leukemia virus (FLV) has been investigated in adhesive clones (FF) of Friend Leukemia cells which were selected via cultivation on top of human fibroblast monolayers. In these adhesive clones a shut-down of FLV production is observed under conditions of culture confluency; this finding is not due either to a reduced number of cell divisions nor to a defective expression of FLV genome as assessed by Northern blot and immunofluorescence studies. Ultrastructural studies showed that virus budding and release into the medium is not detectable under these conditions. Conversely, in confluent FF cell monolayers abundant imperfect type-A enveloped particles were visible, possibly originating from stacks of granular endoplasmic reticulum with thickened membranes. It is postulated that the reduced virus production in adhesive FF monolayers is due to as yet undetermined events taking place during virus maturation at a time coincident with that of cell-cell adhesion under conditions of culture confluency.

Interferon production in L929 cells under impaired translational conditions: comparison of rates of interferon, actin, Newcastle disease and encephalomyocarditis viruses mRNAs initiation of protein synthesis

The pattern of Interferon (IFN) production in virus-infected cells has been compared with the rate of bulk cellular protein synthesis, on one hand, and with the synthesis of representative cell and virus proteins such as actin, the gamma and the NP proteins of encephalomyocarditis (EMC) and Newcastle Disease (NDV) viruses, on the other hand. This was investigated under conditions of impaired protein synthesis such as i) high osmolarity media, ii) a virus-induced shut-off, and iii) in cells exposed to relatively low doses of cycloheximide (CXM), which slow elongation of protein chain and thus favour the translation of low-affinity messenger RNAs (mRNAs). In each instance IFN production was compared with 35S-methionine incorporation into TCA-precipitable materials and into SDS-polyacrylamide gel-analysed proteins. Data obtained from each of the experimental approaches all indicate that IFN production and cellular protein synthesis are modified in a closely related fashion suggesting that their mRNAs share a similar degree of affinity for ribosomes. Conversely, two mRNAs coding for representative EMC and NDV virus proteins exhibit, respectively, the highest and the lowest affinity for ribosomes as compared to actin mRNA.

[Criteria for discontinuation of sustained-release theophylline in children with chronic asthma]

Aim of the study was to ascertain when it is advisable to discontinue the treatment with sustained release theophylline in chronic asthmatic subjects. The population consisted of 23 patients under continuous therapy with Theo-dur since at least 9 months, and free from bronchoobstructive episodes during the last three months. Upon stopping the treatment, instrumental controls showed a statistically significant reduction of mean values of PEF (checked by patients at home three times a day), VC, FEV1, MMEF or FEF25-75, FEV1/VC. The worsening of the physical examinations and anamnestic score is also significant, whilst the exstemporary use of beta 2 agonists increases. Dividing the cases into two populations, formed by worsened patients (11) and by stationary ones (12), it can be observed that the only distinctive features are that the former have been ill for longer, and are older in age. As the majority of patients (12/23) did not exhibit substantial modifications, we consider as proposable the standards we have adopted that means to try a suspension of theophylline in patients free from symptoms for at least 3 months.

Friend murine leukemia virus and spleen focus-forming virus expression in highly malignant interferon-sensitive and interferon-resistant Friend leukemia cells

Analysis of expression of the Friend murine leukemia virus (F-MuLV) and of the spleen focus forming virus (SFFV) has been undertaken in highly malignant interferon (IFN)-sensitive (745) and IFN-resistant (3Cl-8) Friend leukemia cells (FLC), serially passaged intraperitoneally in DBA/2 mice. In vivo passaged 745 cells, as well as the clones derived thereof, did not release Friend virus (FV). Western blot analysis of the plasma membrane fractions of the virus nonproducer 745 cells revealed the lack of gp69/70 glycoprotein expression. At least 10 intraperitoneal passages of virus producer in vitro passaged of virus producer in vitro passaged 745 cells were necessary to obtain the selection of the virus nonproducer phenotype. In contrast in vivo passaged 3Cl-8 cells continued to produce FV even after 100 in vivo passages and expressed gp69/70 antigens to a similar extent as the original in vitro passaged FLC. The expression of F-MuLV and SFFV RNAs in virus producer and virus nonproducer FLC clones has been investigated by means of Northern blot technique using probes specific for either F-MuLV or SFFV. No F-MuLV specific RNA sequences were detected in virus nonproducer 745 clones. SFFV specific RNA transcripts and gp52/55 glycoprotein production could be revealed in all the FLC tested. Southern blot analysis showed the presence of F-MuLV specific sequences in the cellular DNA of virus nonproducer 745 clones. As both in vivo passaged F-MuLV producer 3Cl-8 and F-MuLV nonproducer 745 cells were equally barely immunogenic and highly malignant when injected into syngeneic DBA/2 mice, these results indicate that F-MuLV expression does not result per se in a high immunogenic potential of tumor cells. For the time being, as a specific property of 3Cl-8 versus 745 cells is the interferon-resistant phenotype, it is tempting to speculate that the selection of virus nonproducer cell variants after in vivo passages of interferon-sensitive 745 cells could depend on the presence of low levels of endogenous interferon in normal young mice.

Induction and/or selective retention of proteins in mammalian cells exposed to cycloheximide

Exposure of a number of murine and human cell lines to low graded doses of cycloheximide (CXM) results in a pattern of protein synthesis consisting of enhanced and induced species. These can be divided into two main classes according to molecular weight (20-40 and 70-120 Kd), similar to what has been described for other agents that modify the physiological conditions of growth. In addition, the pronounced synthesis of a hitherto unreported 50-Kd protein species has been consistently observed in all lines tested. Simultaneous exposure of cells to CXM and actinomycin D results in suppressing synthesis of some but not all protein species observed, indicating that control mechanisms at both transcriptional and posttranscriptional levels may be operative in this system.

[Antibiotic therapy in bronchopulmonary diseases in children]

With a wide-spectrum antibiotic the results obtained are not as satisfactory as those obtained with an aimed antibiotic therapy. It is for this reason that a physician must always keep up to date on all the antibiotics and their field of action. Apart the antituberculosis drugs we can currently count on three large families, the penicillins, the cephalosporins, the aminoglycosides, and on a polymorph group made up of erythromycin, chloramphenicol, vancomycin and trimethoprim-sulfamethoxazole (TMP-SMZ). Of all the lung diseases, pneumoniae is without doubt the disease in which the choice of the antibiotic is most difficult and also most determinant. Using a scheme made up of three successive stages could be useful. In the first stage we exploit our knowledge of the prevalence of certain infectious agents in single age group. In the first two months of life gram negative rods, B and D Streptococci and Pneumococcus are the most probable agents, therefore an association of ampicillin and aminoglycoside is recommended. In the pre-school age we find a predominance of Haemophilus influenzae and Pneumococcus and therefore the antibiotic of choice is amoxicillin. In the school age there remains only the Pneumococcus so that the first choice antibiotic is now penicillin. All of this is true for those clinical situations that do not present peculiar characteristics. When this is not the case, we pass on to the second stage which consists of suspecting, on the basis of clinical and instrumental data, of a certain etiologic agent and in choosing an appropriate antibiotic.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aspiration bronchopneumopathies]

Diagnosis of pulmonary disease due to inhalation (PDI) is based on the assumption that not all paediatric pulmonary disease is attributable to infection. Moreover, an accurate investigation of all typical signs of PDI is necessary: drooling, pouring of food from the nose, choking, frequent vomiting and regurgitation. Specific aetiological diagnosis is not difficult when PDI represents only the epiphenomenon of well defined diseases which have disturbed deglutition (e.g. premature birth, cerebral palsy, muscle disease). It is difficult but more important to find the cause of dysphagia when dysphagia itself represents the first sign of dysfunction of the autonomic nervous system (e.g. familial dysautonomy). There are different PDI due to oesophageal dysphagia, e.g. the anomalous artery which presses the oesophagus against the trachea, oesophageal duplication, achalasia. The most frequent cause is gastro-oesophageal reflux, although recently its role in producing symptoms at night in the asthmatic child in much less. Gastro-oesophageal reflux is increased by the Beta2, agonists, the corticosteroids and theophylline. Therefore these drugs, especially theophylline, have to be used with discretion, also if gastro-oesophageal reflux is only suspected (e.g. frequent vomiting by the infant). Anomalous communication between the oesophagus and airways, particularly the laryngotracheo-oesophageal cleft and the isolated tracheoesophageal fistula, are rare diseases and difficult to diagnose. Therefore diagnosis can be delayed for months or even years. Prognosis is extremely variable: repeated inhalation will, however, cause diffuse interstitial fibrosis or, more rarely, a bronchiectasic lesion.

[Anti-influenza vaccination in children]

Due to new methods, including genic recombination, four anti-influenza vaccines are now available: whole inactivated virus vaccine; surface antigen (sub-unit); disrupted virus (split virus); live attenuated virus (used only in the USSR). The safest vaccine at the present time is the split vaccine, as it has been used on large populations (including children) for many years in Japan. Moreover, this is the only vaccine used in the USA on children (over three years of age). Systemic side effects of the split vaccine are exceptional (1 case in 5 million of subjects vaccinated) while local redness or fever are relatively more frequent. The following considerations make vaccination advisable in paediatrics: the increase in number of inpatients with respiratory and other diseases (e.g. febrile convulsions) during influenza epidemics; influenza is a diffuse and highly contagious disease which spreads in the population from children to adults. The split vaccine is not available in Italy, therefore vaccination in our country is limited to children at high risk for influenza related complications. As well as subjects aged over 65, the following children especially need to be vaccinated: patients with chronic disorders of cardiovascular and pulmonary systems (chronic asthma, cystic fibrosis, pulmonary disease due to inhalation) and some metabolic diseases such as diabetes mellitus or Addison's disease.

[Growth and chronic bronchopneumopathies]

The relationship between growth and pulmonary disease has been studied mainly in asthma and cystic fibrosis. In asthma, the most frequent chronic pulmonary disease in childhood, results were conflicting, until the degree of severity of the disease and growth phases were taken into account. Research on 683 children has shown that the percentage of underweight was higher in chronic than intermittent asthma. Moreover, the distribution of underweight patients by ages is different in the two types of asthma: uniform in intermittent asthma; two peaks below the age of 2 and above the age of 12 respectively in chronic asthma. Further data of 65 children treated with slow-releasing theophylline for approximately two years corroborates that puberty is a particularly vulnerable period. Indeed, in the most severe asthmatic males, theophylline is able to completely normalize the growth pattern in childhood but not in puberty. In cystic fibrosis malabsorption makes the study of the relationship between growth and pulmonary disease more complex. The pattern of growth in patients with cystic fibrosis is moving away from the normal pattern with ageing, hence the worsening of pulmonary disease is responsible for the worsening in the growth pattern. The growth pattern today is far better than that of 20 years ago. However, puberty, especially in female patients, is a critical period. Often the puberal spurt is delayed for a few years or is even completely absent. In a group of patients with chronic pulmonary disease due to different causes, weight is more implicated than height and the same pattern was observed in cystic fibrosis. Moreover, as in asthma, weight and height are more implicated in females than males. The entity of alteration observed is midway between the minimal in asthma and the maximal in cystic fibrosis.

Incidence in Italy, genetic heterogeneity, and segregation analysis of cystic fibrosis

Taking advantage of the availability of an archive of consanguineous marriages that gives accurate estimates of consanguinity in Italy, it has been possible to calculate the increase of first- and second-cousin marriages among 624 couples of cystic fibrosis (CF) parents over the general population. From these estimates, the incidence of CF in Italy has been found to correspond approximately to 1/2,000. In turn, the same data have been used to test the hypothesis of genetic heterogeneity of CF, recently proposed, which is based on the presence of two distinct genetic disorders having similar frequencies. If such a hypothesis were true, the number of first-cousin marriages among CF parents should be significantly higher than that observed in our present study. Finally, the segregation analysis of 624 CF sibships has yielded under multiple selection a segregation ratio of 0.252, confirming the recessive mode of inheritance.

Interaction of cholera toxin with gangliosides: differential effects of the oligosaccharide of ganglioside GM1 and of micellar gangliosides

Ultraviolet difference absorption spectra of cholera toxin and its B protomer produced by the oligosaccharide moiety of the monosialoganglioside GM1 were measured as a function of the oligosaccharide concentration. In the presence of oligosaccharide, the spectrum is characterized by three peaks at 282, 288, and 292 nm. A linear increase in difference absorption was observed at these wavelengths vs. oligosaccharide concentration; a saturation effect occurred when the molar ratio of oligosaccharide to cholera toxin was higher than 5. The features of the spectra indicated that the binding with the oligosaccharide affected the environment of tryptophan and tyrosine residues of protomer B. In good agreement with the above results, circular dichroic spectra indicated also a local effect of the binding, mostly restricted to protomer B, while the residues of protomer A remained largely unperturbed. Difference absorption spectra were also measured for cholera toxin in the presence of ganglioside and detergent micelles. The employed gangliosides GD1a and GT1b, unable to bind cholera toxin, interact with the protein by way of contaminating traces of GM1. The preparations of GD1a and GT1b contained 0.8-1.0% (w/w) and 0.4-0.5% (w/w) of GM1, respectively. The results obtained with ganglioside GD1a and GT1b in contrast with the observations made with the oligosaccharide of GM1 indicated a major conformational change of the toxin structure. Upon comparison of the conformational change induced by ganglioside micelles with that induced by sodium dodecyl sulfate it may be suggested that the ganglioside micelle, behaving as a detergent, alters the structure of the toxin such as to induce the penetration of protomer A into the lipid milieu.(ABSTRACT TRUNCATED AT 250 WORDS)

[Aerosol administration in antibiotic therapy of cystic fibrosis]

The aim of this research was to evaluate the response to aerosol antibiotic therapy in Cystic Fibrosis (CF) patients, who because of severe lung disease, were obligated to frequent hospitalizations to undergo intravenous antibiotic therapy. Ten patients, aged 2 to 20 years were submitted to 4 months cycles of aerosol antibiotic therapy for a total of 18 cycles. The daily treatment consisted of carbenicillin 1 g b.d. and gentamicin 80 mgs b.d. At the end of treatment there was a statistically significant improvement of the modified Huang score and of single clinical parameters such as body growth, apetite, physical activity, clinical thoracic evaluation, appearance of sputum. Almost all of the radiographic items remained unchanged: in only 4 cases there was an improvement of the atelectasis-broncopneumonia type lesions. Regarding lung function, there was a statistically significant increase of maximum midexpiratory flow rate (MMEF) from 40% predicted before treatment to 50% predicted after. The reduction of residual volume (RV) from 270% predicted before 170% predicted after treatment was quantitatively more important. Furthermore, the treatment brought about a drastic reduction in number of hospitalizations: from an average of 1,7 hospitalizations/year before to an average of 0,3 hospitalizations/year during treatment. The increased number of isolations of isolations of candida albicans is the only report which favors possible adverse effects, in particular the possibility that this type of treatment favors lung mycosis.

[Diagnosis of cystic fibrosis]

The 4 diagnostic stages of Cystic Fibrosis (C.F.) will be dealt with: prenatal diagnosis, singling out of the heterozygotes, clinical diagnosis and finally, the instrumental confirmation with the sweat test. The techniques for the intra-uterine diagnosis and for singling out of the heterozygotes are still in the experimental stage and cannot yet be put to practical use. The BM test on meconium is, among the numerous neonatal screening, no doubt the most widely used because of its simplicity and low cost. However, our personal experience has confirmed the high incidence of false negative (60%) and of false positive responses (0.8 - 0.9%). This has brought about a reconsideration upon the usefulness of neonatal screenings and this goes for the most recent method based on the dosage of blood trypsin levels. Because of the many difficulties imposed by the neonatal screening, there is a trend towards alternative diagnostic route: the clinical diagnosis. One of the most important objective symptoms even if it may seem trivial, is the reduced ponderal growth: in our personal experience, 51% of patients when diagnosed presented with weight below 10th percentile. One of the most frequent clinical pictures in that of a severe obstructive pulmonary disease of the infant. The high incidence of CF (1 in 1,250 live births) and the high mortality rate in the first year of life (50% of patients die during their first year) indicate that CF weighs heavily on the infantile mortality due to lung disease considered globally. This holds true above all for the Emilia-Romagna region, where the infantile mortality due to lung disease has been drastically reduced. One of the most recently discovered clinical manifestations, more frequent in hot climates, is the metabolic alkalosis. There is then a long series of minor clinical signs which should make one suspect a CF: a few of these are prolapse of the rectum, nasal polyposis, the equivalent of meconium ileus, haemorrhagic symptoms due to hypoprothrombinemia etc. An instrumental confirmation, a sweat test carried out with the quantitative method according to Gibson and Cooke, must always follow each clinical suspect. Unfortunately, alternative methods (such as the Orion C1 electrode or the Medtherm conductivity method) which have very high margins of error are still too widely used, in Italy as well, and should be completely abandoned.

The role of the reactive disulfide bond in the interaction of cholera-toxin functional regions

The chemical reactivity of disulfide bonds towards reducing agents, in the absence of denaturing conditions, in cholera toxin has been studied. Treatment of the toxin with dithiothreitol or other mercaptans gave selective reduction of one of the six disulfide bonds of the protein. This reactive disulfide links two distinct functional regions of the toxin, fragment alpha, which activates adenylate cyclase, and fragment gammabeta5, which recognizes the cell surface receptors. Upon reduction, the two fragments remain bound together and the secondary structure of the protein is retained. The two functional regions have been separated and purified only by methods based on charge differences. When mixed together, purified alpha and purified gammabeta5 fragments spontaneously and rapidly re-form the disulfide bond. However, reduction of the disulfide bond is an absolute requirement for freeing the catalytic site of the alpha functional region. Thus, while other non-covalent binding regions are involved in maintaining cholera toxin molecular structure, the reactive disulfide bond may play a role in the mechanism of cell intoxication.

Heterogeneity of purified cholera toxin

The heterogeneity of Vibrio cholerae toxin, obtained from culture filtrates in homogeneous form by gel filtration and preparative disc gel electrophoresis has been studied. By means of disc electrophoresis on polyacrylamide gel cholera toxin was separated into three forms designated I (5%), II (15%) and III (80%). The toxic activity, amino acid content and molecular weight of the three forms were similar. The difference so far observed between the various electrophoretic fractions is a difference in net charge. Incubation of either cholera toxin II or cholera toxin III at relatively high pH leads to the formation of the more acidic forms. These forms, generated in vitro by deamidation of asparagine and/or glutamine residues, are indistinguishable from the toxins of similar electrophoretic mobilities isolated from crude culture filtrates.