A novel bacterial l-arginine sensor controlling c-di-GMP levels in Pseudomonas aeruginosa.

Nutrients such as amino acids play key roles in shaping the metabolism of microorganisms in natural environments and in host-pathogen interactions. Beyond taking part to cellular metabolism and to protein synthesis, amino acids are also signaling molecules able to influence group behavior in microorganisms, such as biofilm formation. This lifestyle switch involves complex metabolic reprogramming controlled by local variation of the second messenger 3', 5'-cyclic diguanylic acid (c-di-GMP). The intracellular levels of this dinucleotide are finely tuned by the opposite activity of dedicated diguanylate cyclases (GGDEF signature) and phosphodiesterases (EAL and HD-GYP signatures), which are usually allosterically controlled by a plethora of environmental and metabolic clues. Among the genes putatively involved in controlling c-di-GMP levels in P. aeruginosa, we found that the multidomain transmembrane protein PA0575, bearing the tandem signature GGDEF-EAL, is an l-arginine sensor able to hydrolyse c-di-GMP. Here, we investigate the basis of arginine recognition by integrating bioinformatics, molecular biophysics and microbiology. Although the role of nutrients such as l-arginine in controlling the cellular fate in P. aeruginosa (including biofilm, pathogenicity and virulence) is already well established, we identified the first l-arginine sensor able to link environment sensing, c-di-GMP signaling and biofilm formation in this bacterium.

Stability of anterior open bite treatment with bonded spurs associated with high-pull chincup.

OBJECTIVE: To evaluate the stability of anterior open bite (AOB) treatment with bonded spurs associated with high-pull chincup (BS/HPCC). METHODS: The experimental group consisted of 25 Class I AOB patients (15 female, 10 male) treated with BS/HPCC for 1 year. Cephalograms were analysed at pre-treatment (T1), post-treatment (T2) and at the 3-year post-treatment (T3) stage with the patients mean ages of 8.10, 9.14 and 12.18 years, respectively. The control group consisted of 23 subjects (13 female, 10 male) with normal occlusion, with comparable ages at the 3 stages (8.45, 9.45 and 12.50 years at T1, T2 and T3, respectively). T tests were used for intergroup comparisons at T1 and to compare the changes during the 3-year post-treatment period (T2-T3). Intragroup comparison in the treated group was evaluated with dependent t tests between T1 and T2. Correlations between the overbite changes in the T2-T3 period, the pre-treatment AOB severity and the amount of correction achieved during treatment were evaluated with Pearson's correlation coefficient. RESULTS: No statistically significant relapse of the AOB was found at T3. Only 1 patient had a clinically significant AOB relapse. Neither the pre-treatment AOB severity nor the amount of correction was related to overbite changes during the 3-year post-treatment period. CONCLUSIONS: There was no statistically significant relapse of the AOB, and the clinical stability of AOB correction 3-year post-treatment was of 96%.

Influence of miniscrew dental root proximity on its degree of late stability.

Purpose of this study was to evaluate the influence of miniscrew dental root proximity on its late stability degree. 40 miniscrews were inserted between maxillary second premolars and first molars for anterior retraction. Post-surgical radiographs were used to measure the septum width in the insertion site, insertion height, distal and mesial distance from miniscrew to dental root, and the smallest distance between miniscrew and dental root. The miniscrews were divided in two groups according to septum width: ≤3 mm (20 miniscrews) and >3 mm (20 miniscrews). The soft tissue in the insertion site, sensitivity during load, plaque around the miniscrew, and evaluation period were also considered. The results showed no significant difference in miniscrew mobility degree and success rate between groups. Miniscrew dental root proximity did not influence the stability and success rate when the distance between the miniscrew and dental root indicated no periodontal ligament invasion. The overall success rate was 90% and no variable was associated with miniscrew failure. Nevertheless, patient sensitivity was frequently associated with some degree of mini-implant mobility. The septum width did not influence the stability and success rate of this anchorage system, but the extreme root proximity did.

Mini-implant insertion based on tooth crown references: a guide-free technique.

Mini-implant insertion requires accurate surgical technique. This study shows an insertion technique using only tooth crown references; its scientific basis is evaluated radiographically. The sample consisted of 213 inter-radicular septa, evaluated in 53 bitewing radiographs. The proximal contour of adjacent tooth crowns was used to define septum width. The midpoint of the septum width was linked to the interdental contact point to determine septum midline. The distances from septum midline to mesial and distal teeth were measured to evaluate the septum midline centralization degree in two different septum heights. The difference between mesial and distal distances represented the septum midline deviation degree. The mesial and distal distances were compared by t-tests, and the septum midline deviation was correlated with septum height using Pearson's correlation test. The mesial and distal distances were not statistically different in the midpoint of the septum height, but they were different at the apical septum height. There was a moderate correlation (r=0.45) between septum midline deviation and septum height. The tooth crown references evaluated on interproximal radiographs determine a high centralization degree of the septum midline on which the insertion site could be defined. The greater centralization degree was observed at the coronal septum area.

Cephalometric evaluation of Class II malocclusion treatment with cervical headgear and mandibular fixed appliances.

The present study aimed to evaluate the cephalometric changes in Class II patients treated exclusively with cervical headgear (CHG) in the maxillary arch and fixed appliances in the mandibular arch as compared with a control group. The sample comprised 82 lateral cephalograms obtained pre- (T1) and post- (T2) treatment/observation of 41 subjects, divided into two groups: group 1-25 Class II division 1 patients (20 females and five males), with a mean pre-treatment age of 10.4 years, treated for a mean period of 2.5 years and group 2-16 Class II untreated subjects (12 females and four males), with a mean initial age of 9.9 years, followed for a mean period of 2.2 years. Treatment changes between the groups were compared by means of t-tests. The results showed restriction of maxillary forward displacement and also a restriction in maxillary length growth, improvement in the maxillomandibular relationship, restriction of mandibular incisor vertical development, reduction in overjet and overbite, and improvement in molar relationship. It was concluded that this treatment protocol corrected the Class II malocclusion characteristics primarily through maxillary forward growth restriction.

Clinical and laboratory signs of mitochondrial dysfunction secondary to nucleoside analogue antiretroviral therapy are reversible.

During 27 months treatment with 400 mg didanosine and 80 mg stavudine daily but no protease inhibitor therapy, a 50-y-old HIV-positive woman gradually lost 13 kg in weight, her arms, legs and buttocks decreased in volume and she experienced fatigue and polyneuropathy. Laboratory tests showed slight increases in plasma lactate and liver enzyme levels. Eighteen months after withdrawal of antiretroviral drug, the patient was free of fatigue and polyneuropathy and had regained 7 kg in weight as well as most of the volume of her arms, legs and buttocks.

Broad spectrum of time of detection, primary symptoms and disease progression in infants with HIV-1 infection.

The relationship between time of HIV-1 detection, appearance of symptoms and disease progression was studied in all 24 HIV-1-infected infants from a cohort of 117 children who were born to HIV-1-infected mothers and monitored from birth. HIV isolation from plasma and mononuclear cells, HIV-1 DNA PCR (polymerase chain reaction) and, retrospectively, a quantitative assay for HIV-1 RNA were used for virus detection. Two infants possibly exhibited a symptomatic primary HIV infection. More children with than without symptoms during the first year of life progressed to immunological class 3 (P=0.013) and to AIDS or death (P=0.003) during follow-up. HIV-1 was detected within 4 days of age in 4 of 16 infants: 3 of them became symptomatic within 1 year, as did 6 of the remaining 12 infants (not statistically significant). All four infants in whom virus was detected within 4 days of age progressed to severe immunosuppression, compared to 6 of 14 in whom the virus detection test was initially negative prior to the first positive result (n.s.). Two children with previous repeatedly negative HIV detection tests were diagnosed with HIV-1 infection at 8 and 9 months, respectively. Repeated blood sampling is needed for the diagnosis of HIV-1 infection in perinatally exposed infants, and virus detection tests for exclusion of HIV-1 infection must be used with caution.

Three-dimensional evaluation of skeletal and dental asymmetries in Class II subdivision malocclusions.

The objective of this study was to determine if any significant differences existed with regard to dental and skeletal asymmetries between subjects with Angle Class II subdivision malocclusions and subjects with normal occlusions. The sample consisted of 30 subjects in each of the 2 groups. Each possessed a full complement of permanent teeth, including first molars. The average age of subjects was 15.76 years in the Class II subdivision group and 22.42 years in the normal occlusion group. Measurements were obtained with the use of submentovertex, posteroanterior, and corrected oblique cephalometric radiographs. In the submentovertex radiographs, symmetry was assessed by measuring the relative differences in the spatial positions of dental and skeletal landmarks between the right and the left sides in both anteroposterior and transverse dimensions. Coordinate systems were used to represent the mandible, cranial floor, and the maxilla. In the posteroanterior radiographs, symmetry was assessed similarly by measuring the relative differences in the spatial positions of dental and skeletal landmarks between the right and the left sides. In the corrected oblique radiographs, symmetry was assessed by measuring the differences in size of dental and skeletal structures between the right and the left sides. Variables were analyzed with multivariate logistic regression analysis. The results demonstrated that the primary contributor to the differences between the 2 groups was the distal positioning of the mandibular first molars on the Class II side in patients whose mandibles showed no unusual skeletal or positional asymmetries. A secondary contributor was the mesial positioning of the maxillary first molars on the Class II side. Furthermore, the posteroanterior radiographic analysis showed that the more frequent distal positioning of the mandibular molars on the Class II side, compared with the mesial positioning of the maxillary molars on that side resulted in mandibular dental midline deviation to the Class II side more frequently than the maxillary dental midline to the opposite side.

Detection of urographic scars in girls with pyelonephritis followed for 13-38 years.

We report the detection and progression of renal scars in girls prospectively followed from their first recognized urinary tract infection. There were 107 infection-prone subjects with a median age of 7.1 years at the first and 21.7 years at the last urography. Of 51 females who ultimately had lesions, 38 had established scars at the first urography. In 18 subjects, new scars were found in previously undamaged kidneys, 5 already with unilateral scarring. There had been a normal urography after the 5th birthday in 8 of those with later scarring. Worsening of scarring was seen in 10 of the 38 subjects with established scars. The renal damage was in most cases slight or moderate. By stepwise logistic regression analysis, grade of reflux and number of pyelonephritic attacks correlated with scarring, and number of pyelonephritic attacks with new scars and worsening of the lesions. In summary, of the females who ultimately had renal lesions, one-third developed new scars. In most of those with established scars at the first urography, the focal character of lesions suggests that most were also acquired. Since reflux and number of pyelonephritic attacks were identified as risk factors, prevention of renal deterioration should be possible.

A radiographic comparison of apical root resorption after orthodontic treatment with 3 different fixed appliance techniques.

Apical root resorption is an undesirable, but frequent side effect of orthodontic treatment, and therefore improvements in orthodontic techniques and materials are in constant development to decrease it. One of the most recently developed orthodontic techniques is the Bioefficient Therapy that uses contemporary orthodontic materials. Therefore, the primary objective of this study was to compare the amount of root resorption after orthodontic treatment between the simplified standard edgewise technique (group 1), the edgewise straight wire system (group 2), and the Bioefficient Therapy (group 3). It was also the purpose of this investigation to evaluate the amount of root resorption in the whole sample studied and the prevalence of root resorption in the upper and lower incisors. Thus, periapical radiographs were obtained with the long cone paralleling technique for the upper and lower incisors from 30 patients for each group. Root resorption was ranked by scores by 2 examiners who had an excellent intra and interexaminer calibration by Kendall concordance coefficient. Results of the Kruskal-Wallis test demonstrated that group 3 (Bioefficient Therapy) presented less root resorption than the others. It was speculated that the factors responsible for the lesser resorption in this technique were the use of heat-activated and superelastic wires with the bracket design in this technique as well as the use of a smaller rectangular stainless steel wire (0.018 x 0.025 inch) in a 0.022 x 0.028 inch slot during incisor retraction and the finishing stages, as compared to the other techniques. Considering the whole sample, there was no root resorption in 2.25% of the analyzed teeth. There was only a slight resorption in 42.56%, a moderate resorption in 53.37%, an accentuated resorption in 1.40% and an extreme root resorption in only 0.42% of the teeth. The prevalence of resorption for each incisor indicated, in decreasing order, a greater resorption for the upper centrals, followed by the upper laterals, lower centrals, and lastly the lower lateral incisors.

Eruption Guidance Appliance effects in the treatment of Class II, Division 1 malocclusions.

The objective of this research was to cephalometrically evaluate the possible effects of the Eruption Guidance Appliance on the craniofacial complex in a sample of 30 patients, over a treatment period of 26 months. The experimental sample consisted of 30 patients (13 females and 17 males), 27 of which presented with a Class II, Division 1 malocclusion and 3 with a Class I malocclusion. The mean initial chronologic age was 9 years; the treatment period lasted 26 months. A control group was used for comparison and consisted of 30 subjects (13 females and 17 males) of similar ages and spanned a similar observation period. Twenty-six subjects of this control group had Class II, Division 1 malocclusions, and 4 had Class I malocclusions. Lateral cephalometric headplates were obtained for the experimental group initially and after 26 months of treatment. The subjects in the control group were randomly selected from a serial growth study sample from the Orthodontic Department at Bauru Dental School, University of São Paulo, for whom cephalometric headplates were obtained annually from 4 to 18 years of age. Comparative statistics were used to assess possible differences between the experimental and control groups during the 26-month period of observation. Results demonstrated statistically significant increases in mandibular growth, degree of mandibular protrusion, lower anterior and total anterior face height, mesial migration of the lower molars, and mandibular posterior dentoalveolar height. There was also lingual tipping and retrusion of the upper incisors, linear protrusion of the lower incisors, improvement in the maxillomandibular relationship and in molar relationship, as well as a significant decrease in the overjet and overbite and an inhibition of the vertical development of the upper incisors. The study demonstrated no significant changes in maxillary growth during the evaluation period. It was concluded from these results that the effects of the Eruption Guidance Appliance during this time period were mostly dentoalveolar, with a smaller, but significant, skeletal effect.

Long-term pattern of HIV-1 RNA load in perinatally infected children.

The objective of this study was to describe the natural history of HIV-1 RNA load in vertically HIV-1-infected children. HIV-1 RNA in 156 plasma or serum samples (1-14, median 4 from each child) from 32 vertically HIV-1-infected children was detected with the NASBA technique (Organon Teknika, The Netherlands). Twenty-one children were prospectively followed from birth, and 11 were identified and included at the age of 7-89 (median 61) months. The highest numbers of HIV-1 RNA copies were seen at 1.5-3 months of age. A quadratic curve model showed a reduction of HIV-1 RNA with increasing age up to approximately 8 years, and thereafter increasing numbers, p(age) = 0.002, p(age2) = 0.008. This pattern was not typical for individual children in whom a great variation in HIV-1 RNA numbers was seen over time. The interval from birth to the first HIV-1 RNA peak ranged from 1.5 months to more than 2 years. The HIV-1 RNA levels remained relatively high and fluctuating over the years in symptomatic as well as in long-term asymptomatic children. This makes HIV-1 RNA determination in children more difficult to use than in adults, as the only tool for prediction of disease progression and for initiation of therapy.

Nickel hypersensitivity reaction before, during, and after orthodontic therapy.

Nickel is a strong biological sensitizer and consequently may induce a delayed hypersensitivity reaction (type IV immune response). Because nickel is a component of the majority of the orthodontic alloys, the objectives of this cross-sectional study were to determine the prevalence of nickel hypersensitivity reaction before, during, and after orthodontic therapy with conventional stainless steel brackets and wires; to evidence the induction of this reaction by the orthodontic appliances; and to characterize the nickel hypersensitive persons. Nickel patch tests and a questionnaire were used to evaluate the hypersensitivity to this metal. The total sample consisted of 170 patients, 105 females and 65 males, from the orthodontic department at Bauru Dental School, University of São Paulo. They were divided into three groups as follows: A (n = 60), patients before the beginning of orthodontic therapy; B (n = 66), patients currently undergoing orthodontic treatment, and C (n = 44), patients who had undergone orthodontic treatment previously. The chi-square test (chi2) showed an allergic reaction in 28.3% of the total sample with 23% female and 5.3% male. This indicated a gender difference (chi2 = 10.75, p < 0.001). There was a positive association between nickel hypersensitivity and previous personal allergic history to metals (chi2 = 34.88, p < 0.0001) as well as with the daily use of metal objects (chi2 = 11.95, p < 0.0005). There was no statistically significant difference in the prevalence of contact dermatitis among the three groups (chi2 = 0.39, p = 0.848). This suggests that orthodontic therapy with conventional stainless steel appliances does not initiate or aggravate a nickel hypersensitivity reaction.

Dental maturation in subjects with extreme vertical facial types.

The purpose of this research was to investigate whether there is a difference in dental maturation between skeletal open bite and skeletal deep bite subjects of the same chronological age. The material consisted of 40 lateral headfilms and 40 panoramic radiographs of 20 male and 20 female white subjects, with a mean chronological age of 9 years and 2 months (range: 7 years 6 months to 10 years 11 months). These subjects were selected on the basis of lower anterior face height as a percentage of total face height and on the amount of open or deep-bite from a total sample of 400 subjects. The persons exhibiting the most extreme values at both ends of the distribution were selected to create two groups with 20 subjects in each (10 males and 10 females). Thus, the groups represented subjects with either a large lower anterior face height associated with an open bite or a small lower anterior face height associated with a deep bite. A double blind determination of dental maturation, expressed by dental age, for each subject was performed on the panoramic radiographs using the system of Demirjian et al. (1973). A covariance analysis was used to eliminate variability introduced by the large age range of the sample. The skeletal open bite and deep bite groups presented mean dental ages of 120.48 and 114.00 months, respectively. Statistical analysis demonstrated that this difference was statistically significant at P < 0.05. Therefore, it seems that skeletal open bite subjects presented a slight tendency to have an advanced dental maturation, expressed by dental age, as compared with skeletal deep bite subjects.

[The year of the world aids day: children in a world of AIDS]. / Arets världsaidsdag: barn i en värld med aids.

PIP: "Children living in a world with AIDS" was the theme of a UNAIDS campaign launched because 1 million children are infected with HIV and 9 million children have become orphans due to AIDS (90% in sub-Saharan Africa). During 1996 alone, 400,000 children were infected: 90% were infected during pregnancy, delivery, or while breast feeding; the remaining 10% were infected sexually or via blood or blood products. In Africa, only one-third of HIV-infected children survive their 3rd birthday, and 8% of all children in Zimbabwe have lost their mothers to AIDS. A similar situation is rapidly evolving in Asia and South America. In Spain and Italy, more than 600 children have AIDS; most of them were infected through drug-abusing mothers. In France the figure is comparable, but here a large segment is represented by children of mothers from African countries. The total number of children with AIDS in the European Community is 2800: 86% were infected through their mothers. Romania has 4000 children with AIDS, who were predominantly infected via nonsterile syringes and blood transfusion. The European Commission has a specific AIDS prevention program, which addresses the measurement of disease spread, counteracting the disease, information and education, support for persons with HIV/AIDS, and countering discrimination. The risk of mother-to-child HIV transmission can be reduced from 25% to 8% by zidovudine (AZT) treatment during pregnancy and delivery.^ieng

Girls prone to urinary infections followed into adulthood. Indices of renal disease.

This study describes blood pressure and renal function, as well as indices of renal disease, in females with and without renal scarring followed from their first urinary tract infection (UTI) in childhood. Of the 111 patients with a median follow-up time of 15 years, 54 had renal scarring (reflux nephropathy) on urography, which was severe in 19 and moderate in 35. The glomerular filtration rate was lower in patients with severe renal scarring and correlated with renal area on urography. However, the filtration rate was decreased below the lower reference limit in only 7 patients, with a lowest value of 70 ml/min per 1.73 m2. The diastolic blood pressure was higher in women with severe scarring. Hypertension of at least 140/90 mmHg was diagnosed in 3 of 54 (5.5%) females with renal scarring, 2 before and 1 at the follow-up examination. The excretion of albumin in urine was low and not correlated to filtration rate. Tubular enzymes in urine were similar in all groups. Thus the renal function was well preserved and the incidence of hypertension low. Within this range of renal function, the level of albumin in urine did not predict the degree of renal scarring.