Maxillary tridimensional changes after slow expansion with leaf expander in a sample of growing patients: a pilot study.

AIM: The aim of this study is to evaluate the dento-alveolar effects of slow maxillary expansion using the Leaf Expander in a sample of growing patients with maxillary transverse deficiency, unilateral cross bite and mandibular shift. MATERIALS AND METHODS: The study included 10 patients, 3 male and 7 female (mean age 7.5 + 7 months), treated with Leaf Expander anchored on the upper deciduous teeth. Digital models were obtained by a lab scan of the pvs impressions at the beginning of the therapy (T1) and at the removal of the palatal expander (T2). Five parameters were measured: 1) the distance between the first upper permanent molars; 2) the distance between the upper second deciduous molars; 3) the distance between the upper canine cusps 4) the distance between the first lower permanent molars; 5) the distance of the lower canine cusps. RESULTS: In all patients complete correction of posterior crossbite was achieved on average in 4 months, with a spontaneous expansion of the upper first permanent molars. Significant increases in the dento-alveolar transversal diameters were obtained. Increases were also observed in the anterior mandibular arch diameter (+ 1 mm). CONCLUSIONS: These findings suggest that slow maxillary expansion using Leaf Expander appliance could be a reasonable alternative to conventional maxillary expansion therapy in the early mixed dentition.

Lipoxygenase-mediated pro-radical effect of melatonin via stimulation of arachidonic acid metabolism.

We have shown that melatonin immediately and transiently stimulates intracellular free radical production on a set of leukocytes, possibly as a consequence of calmodulin binding. We show here that melatonin-induced ROS are produced by lipoxygenase (LOX), since they are prevented by a set of LOX inhibitors, and are accompanied by increase of the 5-LOX product 5-HETE. LOX activation is accompanied by strong liberation of AA; inhibition of Ca(2+)-independent, but not Ca(2+)-dependent, phospholipase A2 (PLA2), prevents both melatonin-induced arachidonic acid and ROS production, whereas LOX inhibition only prevents ROS, indicating that PLA2 is upstream with respect to LOX, as occurs in many signaling pathways. Chlorpromazine, an inhibitor of melatonin-calmodulin interaction, inhibits both ROS and arachidonic acid production, thus possibly placing calmodulin at the origin of a melatonin-induced pro-radical pathway. Interestingly, it is known that Ca(2+)-independent PLA2 binds to calmodulin: our results are compatible with PLA2 being liberated by melatonin from a steady-state calmodulin sequestration, thus initiating an arachidonate signal transduction. These results delineate a novel molecular pathway through which melatonin may participate to the inflammatory response.

Oxidative Bax dimerization promotes its translocation to mitochondria independently of apoptosis.

Bax is a cytosolic protein, which in response to stressing apoptotic stimuli, is activated and translocates to mitochondria, thus initiating the intrinsic apoptotic pathway. In spite of many studies and the importance of the issue, the molecular mechanisms that trigger Bax translocation are still obscure. We show by computer simulation that the two cysteine residues of Bax may form disulfide bridges, producing conformational changes that favor Bax translocation. Oxidative, nonapoptogenic treatments produce an up-shift of Bax migration compatible with homodimerization, which is reverted by reducing agents; this is accompanied by translocation to mitochondria. Dimers also appear in pure cytosolic fractions of cell lysates treated with H2O2, showing that Bax dimerization may take place in the cytosol. Bax dimer-enriched lysates support Bax translocation to isolated mitochondria much more efficiently than untreated lysates, indicating that dimerization may promote Bax translocation. The absence of apoptosis in our system allows the demonstration that Bax moves because of oxidations, even in the absence of apoptosis. This provides the first evidence that Bax dimerization and translocation respond to oxidative stimuli, suggesting a novel role for Bax as a sensor of redox imbalance.

Apoptotic GSH extrusion is associated with free radical generation.

Reactive oxygen species (ROS) are involved in many forms of apoptosis and mediate apoptosis in a number of cell types. In this paper, we use a variant of U937 monocytic cells (U937 HX) that show different biochemical features with respect to standard U937. Apoptotic standard U937 extrude reduced glutathione (GSH) and generate free radicals concomitantly with loss of mitochondria transmembrane potential (mt Deltapsi). These events are correlated with the extrusion of intracellular GSH. Conversely, apoptotic U937 HX cells retain GSH, and the loss of mt Deltapsi is not accompanied by generation of free radicals. The perfect inverse correlation between (a) ROS generation and (b) the presence of intracellular GSH during apoptosis suggests novel mechanisms to finely tune ROS generation in apoptosis.

Enhancement of genetic instability in human B cells by Epstein-Barr virus latent infection.

The level of genetic instability, as assessed by micronucleus (MN) formation, was higher in Epstein-Barr virus (EBV)-converted B-cell lines with one copy of the EBV genome integrated in each cell than in the parental, EBV-negative, B lymphoma cells. MN induced by EBV latency, as analysed by in situ hybridization, contained mainly centromeric regions, indicating that the presence of EBV affects the segregation of entire chromosomes. The instability was inhibited by treatment with antioxidants. Flow cytometric analysis indicated that there was a higher basal level of peroxides in EBV(+) cells. Direct oxidative stress caused by hydrogen peroxide (which is known to be both apoptogenic and mutagenic) enhanced the number of MN only in an EBV-converted clone. These cells were also resistant to apoptosis, as expected, suggesting that in the parental EBV cells apoptosis may efficiently eliminate cells with genetic damage. These results show for the first time a direct involvement of EBV in the induction of genetic instability, suggesting that it could contribute to tumour progression.

The response of pigs inoculated with a thymidine kinase-negative (TK-) pseudorabies virus to challenge infection with virulent virus.

12 Large-White-Landrace piglets were subdivided in four groups of 3 and housed in separate units. The piglets of three groups were inoculated with the 86/27V 6C2 thymidine kinase negative (TK-) mutant of pseudorabies virus (PRV), by different routes. A second inoculation with the same mutant was given to the pigs 21 days later. The animals of a fourth group were left as uninoculated controls. 21 days following the second inoculation with the TK- mutant all pigs were challenge infected with the virulent PRV. On post challenge day (PCD) 30 all pigs were killed and samples for virus detection and histology were taken from several organs. The inoculated TK- mutant of PRV did not induce any ill effects in the pigs except a transient febrile reaction in some animals. Virus was recovered from nasal swabbings from one pig 2 days after the first inoculation of the mutant. After challenge exposure with virulent PRV, the TK- mutant-inoculated pigs were apparently protected, whereas the control pigs all were severely affected and recovered very slowly over 3 weeks. Virus was isolated from the nasal swabbings from the TK- mutant-inoculated pigs on PCDs 2 and 4, whereas the nasal swabbings from the control piglets were all positive for virus from PCD 2 through PCD 10. DNA analysis of the virus recovered showed a pattern identical to that of the virulent PRV. Histologic lesions were found in the respiratory and the central nervous systems, however, the lesions in the TK- mutant-inoculated pigs were much milder compared to those registered for the control pigs. Virus was not isolated from any of the tissue samples that were tested, but viral DNA with sequences typical of PRV genome was detected by PCR in all samples of trigeminal ganglia from either the TK- mutant-inoculated pigs or from the controls.

Interferon alpha-2B and ribavirin in combination for patients with chronic hepatitis C who failed to respond to, or relapsed after, interferon alpha therapy: a randomized trial.

PURPOSE: To assess the efficacy of interferon alpha-2b and ribavirin in combination in the treatment of patients with chronic hepatitis C who had either failed to respond to therapy with interferon alpha (nonresponders), or who had relapsed after interferon therapy (relapsers). SUBJECTS AND METHODS: Four hundred patients with chronic hepatitis C (200 nonresponders and 200 relapsers) were randomly assigned in equal numbers to receive either subcutaneous administration of recombinant interferon alpha-2b (3 million units three times per week) and ribavirin (1,000 to 1,200 mg/daily orally) or interferon alpha-2b alone (6 million units three times per week). Both ribavirin and interferon alpha-2b were given for 24 weeks. The patients were then followed for an additional 24 weeks. RESULTS: At the end of the treatment period, normalization of serum alanine aminotransferase levels and absence of hepatitis C virus RNA were seen in 21% of nonresponders and in 39% of relapsers who were treated with interferon alpha-2b and ribavirin, compared with 5% of nonresponders (P = 0.001) and 9% of relapsers treated with interferon alpha-2b alone (P <0.001). At the end of follow-up, 14% of nonresponders and 30% of relapsers treated with the combination therapy had a sustained response, compared with 1% of nonresponders (P = 0.001) and 5% of relapsers treated with interferon alpha alone (P <0.001). CONCLUSIONS: A 24-week course of treatment with interferon alpha-2b and ribavirin offers a chance of sustained response, whereas retreatment with interferon alpha-2b alone does not give satisfactory results. The role of long-term therapy in inducing prolonged remission remains to be explored.

Magnetic fields increase cell survival by inhibiting apoptosis via modulation of Ca2+ influx.

Static magnetic fields with intensities starting from 6 gauss (6x10(-4) tesla, T) were found to decrease in an intensity-dependent fashion, reaching a plateau at 6 x 10(-3) T, the extent of cell death by apoptosis induced by several agents in different human cell systems. This is not due to a change in the mode of cell death (i.e., to necrosis) or to a delay of the process itself; rather, the presence of magnetic fields allows the indefinite survival and replication of the cells hit by apoptogenic agents. The protective effect was found to be mediated by the ability of the fields to enhance Ca2+ influx from the extracellular medium; accordingly, it was limited to those cell systems where Ca2+ influx was shown to have an antiapoptotic effect. Magnetic fields thus might interfere with human health by altering/restoring the equilibrium between cell death and proliferation; indeed, the rescue of damaged cells may be the mechanism explaining why magnetic fields that are not mutagenic per se are often able to increase mutation and tumor frequencies.

Experimental infection of pigs with a thymidine kinase negative strain of pseudorabies virus.

Sixteen 20 day old pigs, devoid of neutralizing antibody to pseudorabies virus (PRV), were divided into two groups of eight, an the animals of each group were housed in a separate unit. In each group 6 pigs were inoculated intranasally with the thymidine kinase (TK-) mutant (Group 1) or the field strain of PRV (Group 2), each pig receiving an inoculum of 4 ml. The remaining 2 pigs in each group served as uninoculated controls. The only clinical sign observed in the pigs of Group 1 was a transient febrile reaction, in the case of six pigs inoculated with the TK- mutant of PRV, whereas no signs of disease were seen in the uninoculated controls. The virus was isolated from the 6 infected pigs of the group only on post infection day (PID) 2, whereas it was never isolated from the controls. By contrast, the pigs of Group 2, had a severe clinical response and one, among those that were inoculated with the field strain of the PRV, died on PID 9. Virus was consistently isolated from all pigs of Group 2, inoculated and control. On PID 30 all pigs, i.e. the 8 of Group 1 and 7 of the Group 2 which survived to the infection, were subjected to dexamethasone (DMS) treatment. After DMS treatment virus was never isolated from the nasal swabbings obtained from the pigs of Group 1, whereas it was consistently isolated from pigs of Group 2. After 30 d from the start of DMS treatment the pigs were killed and several tissues were collected from each pig for virus detection, by isolation in tissue culture and by PCR analysis. At necropsy no lesions were found in pigs of Group 1, whereas acute pneumonia and gliosis in the trigeminal ganglia were observed in pigs of Group 2. Virus was never isolated from any of the tissues taken from pigs of both, Group 1 and Group 2, nevertheless sequences of PRV were detected by PCR analysis in the trigeminal ganglia of the pigs of both Groups.

The region 3' to Calpha1 gene of human IG heavy chain displays a polymorphic duplicated sequence and encodes an RNA associated with polysomes.

A highly spread polymorphism flanking the 3. Calpha1 human IG heavy chain gene was identified. This polymorphism allowed the detection of an internal duplication within the 3' flanking region of both Calpha1 and Calpha2. This region has a regulatory function with four enhancer structures also present at the 3' end of the human Calpha2 as well as in that of mouse and rat single Calpha genes. The 5682-bp sequence of clone lambdapl8 described here starts 3' of Calpha1 and presents three open reading frames; one of them contains part of the tandem repeats with the 20-bp consensus described previously that is expressed in a poly(A)+ RNA and found in three dbEST clones of the human tonsillar cDNA library. Here, we demonstrate that in the CLF1 B lymphoblastoid cell line, this transcript is associated with polysomes. We also discuss the possibility of the presence of a new regulatory gene that does not encode an immunoglobulin and maps in the human IG heavy chain gene cluster.

Retinoic acid treatment induces apoptosis or expression of a more differentiated phenotype on different fractions of cultured fetal rat hepatocytes.

The present study reports the effects of retinoic acid (RA) on cultured fetal rat hepatocytes. We show that RA treatment induces both differentiation and apoptosis. Hepatocytes cultured for 48 hours in the presence of 5 microl/L RA form junctional complexes in the areas of contact between neighboring cells and develop bile canaliculi, typical features of mature and well-differentiated cells. At the same time, about 20% of cells are induced to die by apoptosis, and the percentage of apoptotic cells increases according to the concentration of RA used and the duration of treatment. The induction of apoptosis, studied at the morphological and biochemical levels, revealed that, in our system, the classical compaction of chromatin occurs only during the final stages of the process; instead of the common marker of apoptosis, i.e., the "DNA ladder" pattern of fragmentation, megabase-sized fragments were found. These observations provide further evidence of the existence of fundamental differences in the mechanisms of apoptosis among cell types. To investigate the molecular mechanism of the effects of RA, we evaluated the expression of two proteins, c-myc and p53, which are known to be involved in both cell differentiation and apoptosis. The data obtained show that the amount of p53 remained unchanged after RA treatment. On the contrary, a dose-dependent reduction in c-myc levels was found, suggesting that RA action may be mediated by modulation of this oncogene. Our findings regarding the apoptosis-inducing effect of RA, which was not found in adult hepatocytes, suggest a possible relationship between this phenomenon and the proliferative capacity and/or differentiation state of hepatocytes.

Mitochondrial DNA in platelets from aged subjects.

This study aimed to assess platelets as a possible model for screening the accumulation of mitochondrial DNA mutations, particularly during normal ageing. For this purpose we isolated platelets from young and old donors selected by lack of systemic and haematological diseases. We studied the accumulation of a particular deletion (4977-bp deletion) that usually accumulates in an age-related manner in different post-mitotic tissues, such as brain, heart and skeletal muscle, and in some non-post-mitotic tissues (skin, liver). Using different primers, we failed to detect this particular species of deletion in platelets both from young and old individuals. However, we cannot exclude the presence of other species of deletions or point mutations affecting the mitochondrial DNA in platelets during the aging process.

In vitro study of gingival fibroblasts from normal and inflamed tissue: age-related responsiveness.

The aim of this study was to characterize some phenotypic expressions of fibroblasts from the human oral mucosa. Gingival and lower forearm fibroblasts from young (20-30 years) and elderly (> 60 years) subjects were analyzed. Gingival fibroblasts were taken from donors with (P) and without (NP) periodontal disease, while skin biopsies were taken from healthy subjects. Cell proliferation was assessed by evaluating the cell multiplication coefficient (C.M.C.). The proliferation potential of gingival fibroblasts from elderly individuals with and without periodontopathy did not differ from that of young subjects in the same condition but differed significantly in the skin samples. Enzyme neutral endopeptidase (EC 3.4.24.11) (NEP) activity, studied as a possible marker of cell ageing, showed an age-related increase in human skin fibroblasts but not consistently in gingival fibroblasts from individuals with or without periodontal disease. Cell area and substrate adhesion were evaluated by morphometric analysis. There were no significant differences between elderly P and NP subjects, while significant differences were observed between young and elderly P subjects. In conclusion, proliferative capacity and NEP activity in gingival fibroblasts did not appear to be age-related, probably because their microenvironment is continually moistened by saliva, which continues to contain growth factors, notably EGF, even into senescence. Tissue reaction and repair are important clinical and therapeutic implications.

Protease inhibitors block apoptosis at intermediate stages: a compared analysis of DNA fragmentation and apoptotic nuclear morphology.

The possible correlation between DNA digestion and changes in nuclear morphology in apoptosis was studied by blocking the apoptotic process at intermediate stages. The apoptogenic action of three drugs: etoposide, puromycin, tributyltin, was contrasted with protease inhibitors with different specificity on U937 cells. The inhibitors interfered with the development of the apoptotic features without shifting cell death to necrosis: treated cells showed abnormal morphologies, which could be recognized as intermediate stages of apoptosis; accordingly, DNA analysis showed an inhibitor-dependent block of the apoptotic DNA digestion. The comparison between size of DNA fragments and nuclear morphology suggested the following correlations: loss of normal nuclear shape with the appearance of a > or = 2 Mb DNA band; ongoing chromatin condensation with the progressive DNA digestion up to 50 kb; nuclear fragmentation with DNA laddering. Protease inhibitors in etoposide-treated cells did not allow the formation of 700-300 kb fragments, suggesting that they possibly derive from a cell-mediated effect.

Integration of an Epstein-Barr virus episome 3' into the gene encoding immunoglobulin heavy-chain alpha 1 in a lymphoblastoid cell line.

For the first time we have characterized an unoccupied site of Epstein-Barr (EBV) virus integration in a lymphoblastoid cell line, RGN1. The site of integration is about 1.5 kb downstream from the gene encoding the heavy chain constant alpha 1, specifying immunoglobulin A (IgA). Sequence and Southern analysis allowed us to hypothesize that integration occurred via a double exchange involving the viral latent origin of DNA replication (oriP) and the human DNA. The region involved in the integration is transcribed into poly(A)+ RNA in all the tested lymphoid lines, but not in the RGN1 line. We suggest a mechanism of integration primed by interactions between oriP and cell ori and its potential role in the establishment and/or evolution of EBV-carrying lines.

A study on the characteristics of La Sota strain of Newcastle disease virus adapted to grow in a cell line from bovine embryo kidney (BS/BEK).

The lentogenic La Sota strain of Newcastle disease virus (NDV) was adapted to grow in the BS/BEK cell line of bovine embryo kidney origin with a infectious titre similar to that in chicken embryos. No modification in the biological properties was detected after serial passages in the cell line, as indicated by CPE and by size and shape of the plaques. By contrast, the intracerebral pathogenicity index test, determined in 1-day-old chicks, was lower than for La Sota grown in chicken embryos. However, the immunogenicity of the cell culture adapted virus did not show any variation as demonstrated by serological response and by protection following challenge with virulent NDV. Accordingly, it appears that La Sota grown in cell cultures has retained its biological and immunological characteristics and if these results are confirmed by field trials and long term protection tests, the use of the BS/BEK cell line could be an alternative to chicken embryos for the cultivation of NDV.

A study of two mutant strains of pseudorabies virus (PRV) unable to express thymidine kinase (TK) function.

Two mutant strains of pseudorabies virus (PRV) were selected from the virulent 86/27V virus treated with chemical drugs. The viruses, named 6A1 and 6C2, respectively, appeared to be unable to express thymidine kinase function, as demonstrated by the autoradiography test. They showed a reduced virulence for some susceptible animal species (chickens, mice, rabbits, calves, lambs and piglets) and virus was isolated sporadically. The mutant viruses appeared to be able to protect animals against infection with the virulent strain of PRV. At gross, as well as at histological examination, no lesions in apparatus, system and tissues were detected in pigs inoculated with 6A1 and 6C2 viruses. By contrast, rabbits treated with 6C2 mutant strain presented lymphomononucleated cuffs, microgliosis, and neuronophagia in some areas of the brain. This focal spreading, together with the absence of neuronal necrosis and intranuclear inclusions, suggest an infection induced by a modified strain of PRV.

Ischaemic pontomedullary transection with incomplete locked-in syndrome. A case report with MRI.

We describe a case of incomplete locked-in syndrome (LIS) due to basilar artery thrombosis, in which MRI showed a complete, sharply demarcated infarct at the pontomedullary junction. This supports experimental data showing that the lower reticular formation is not critical for the maintenance of consciousness. To our knowledge, this is the first reported case of ischaemic pontomedullary transection with LIS.

Successful nonoperative treatment of tuberculous spinal epidural abscess with cord compression: the role of magnetic resonance imaging.

A patient is described with a tuberculous spinal epidural abscess and signs of cord compression, who was successful treated without surgery. Magnetic resonance imaging, in addition to its role as a diagnostic tool, was helpful in monitoring the resolution of inflammation.