Predictive power of "a minima" models in biology

Many apparently complex mechanisms in biology, especially in embryology and molecular biology, can be explained easily by reasoning at the level of the "efficient cause" of the observed phenomenology: the mechanism can then be explained by a simple geometrical argument or a variational principle, leading to the solution of an optimization problem, for example, via the co-existence of a minimization and a maximization problem (a min-max principle). Passing from a microscopic (or cellular) level (optimal min-max solution of the simple mechanistic system) to the macroscopic level often involves an averaging effect (linked to the repetition of a large number of such microscopic systems with possible random choice of the parameters of each of them) that gives birth to a global functional feature (e.g. at the tissue level). We will illustrate these general principles by building in four different domains of application "a minima" models and showing the main properties of their solutions: (1) extraction of a minimal RNA structure functioning as the first "peptidic machine," a kind of ancestral ribosome; (2) study of a genetic regulatory network of Drosophila centred on Engrailed gene and expressing successively two genes inside a limit cycle; (3) study of a genetic network regulating neural activity and proliferation in mammals; and (4) study of a simple geometric model of epiboly in zebrafish.

Pharmacokinetic interaction study between eslicarbazepine acetate and lamotrigine in healthy subjects

OBJECTIVE

Anti-epileptic drugs are often used in combination. Both eslicarbazepine (main metabolite of eslicarbazepine acetate, ESL) and lamotrigine undergo conjugation with glucuronic acid, and both eslicarbazepine and its glucuronide and lamotrigine glucuronide undergo extensive renal elimination; therefore, there is a potential for interaction. This study investigated the interaction between ESL and lamotrigine in healthy subjects.

METHODS

Open-label study in two parallel groups of 16 healthy volunteers each. After an 8-day treatment with ESL or lamotrigine, ESL (1200 mg once-daily) and lamotrigine (150 mg once-daily) were co-administered for 19 days. Geometric mean ratios (GMR) and 90% confidence intervals (90% CI) for maximum plasma concentration (C(max)) and area under the plasma concentration-time curve in the dosing interval (AUC(0-24)) were calculated for eslicarbazepine (ESL active metabolite) and lamotrigine.

RESULTS

The C(max) and AUC(0-24) GMR (90% CI) were, respectively, 95% (87-102%) and 96% (91-102%) for eslicarbazepine, and 88% (82-94%) and 86% (81-92%) for lamotrigine. The 90% CI of the C(max) and AUC(0-24) GMR fell within the prespecified acceptance interval (80-125%) both for eslicarbazepine and lamotrigine.

CONCLUSION

There was no significant pharmacokinetic interaction between ESL and lamotrigine in healthy subjects. Therefore, no dosage adjustment appears to be usually required in either lamotrigine or ESL when the drugs are co-administered.

Predictive factors for the detection of CIN II-III in the follow-up of women with CIN I

PURPOSE OF INVESTIGATION

To determine which factors may increase the risk that women diagnosed with CIN I may later develop CIN II-III.

METHODS

A prospective study of 174 women with a grade 1 intraepithelial lesion (CIN I) confirmed by biopsy, with a follow-up time of at least one year. The following factors were studied: age, HPV infection, HPV infection by a high-risk genotype, the HPV genotypes involved, coinfection by several HPV genotypes and duration of follow-up. These factors were correlated with later detection of CIN II-III by biopsy during follow-up. Statistical analysis was performed using SPSS.

RESULTS

CIN II-III was detected at the follow-up in 24 of 174 women included in the study (13.7%), in four cases by colposcopically directed biopsy and in 20 by LLETZ. Correlation of the factors studied with the incidence of CIN II-III in this group showed that the only statistically significant factors were overall HPV infection and HPV infection by genotypes 31 and 70 (Chi-square and Fisher's test, p < 0.05, respectively), while the duration of follow-up came close to statistical significance (Student's test, p = 0.052).

CONCLUSION

HPV infection and duration of follow-up are predictive factors for the detection of CIN II-III in follow-up care for women with CIN I.

Maternal consumption of polyphenol-rich foods in late pregnancy and fetal ductus arteriosus flow dynamics

OBJECTIVE

To test the hypothesis that maternal consumption of polyphenol-rich foods during third trimester interferes with fetal ductal dynamics by inhibition of prostaglandin synthesis.

STUDY DESIGN

In a prospective analysis, Doppler ductal velocities and right-to-left ventricular dimensions ratio of 102 fetuses exposed to polyphenol-rich foods (daily estimated maternal consumption >75th percentile, or 1089 mg) were compared with 41 unexposed fetuses (flavonoid ingestion <25th percentile, or 127 mg).

RESULT

In the exposed fetuses, ductal velocities were higher (systolic: 0.96+/-0.23 m/s; diastolic: 0.17+/-0.05 m/s) and right-to-left ventricular ratio was higher (1.23+/-0.23) than in unexposed fetuses (systolic: 0.61+/-0.18 m/s, P<0.001; diastolic: 0.11+/-0.04 m/s, P=0.011; right-to-left ventricular ratio: 0.94+/-0.14, P<0.001).

CONCLUSION

As maternal polyphenol-rich foods intake in late gestation may trigger alterations in fetal ductal dynamics, changes in perinatal dietary orientation are warranted.

Efficacy and safety of 800 and 1200 mg eslicarbazepine acetate as adjunctive treatment in adults with refractory partial-onset seizures

OBJECTIVES

To evaluate the efficacy and safety of eslicarbazepine acetate (ESL) as adjunctive therapy in adults with partial-onset seizures.

MATERIAL AND METHODS

Double-blind, placebo-controlled, parallel-group, multicenter study consisting of an 8-week baseline period, after which patients were randomized to placebo (n = 87) or once-daily ESL 800 mg (n = 85) or 1200 mg (n = 80). Patients received half dose during 2 weeks preceding a 12-week maintenance period.

RESULTS

Seizure frequency over the maintenance period was significantly (P < 0.05) lower than placebo in both ESL groups. Responder rate was 23% (placebo), 35% (800 mg), and 38% (1200 mg). Median relative reduction in seizure frequency was 17% (placebo), 38% (800 mg), and 42% (1200 mg). The most common adverse events (AEs) (>10%) were dizziness, somnolence, headache, and nausea. The majority of AEs were of mild or moderate severity.

CONCLUSIONS

Once-daily treatment with ESL 800 and 1200 mg was effective and generally well tolerated.

Chronic myeloid leukaemia in two multiple sclerosis patients on interferon beta-1a

Haematological problems are commonly associated with use of beta-interferon in multiple sclerosis (MS) patients. However these problems are usually benign and are reversible when the drug is stopped. We describe two patients, with the diagnosis of MS, who developed leucocytosis. Cytogenetic studies showed the presence of the Philadelphia chromosome in all the cells analysed, confirming the diagnosis of chronic myeloid leukaemia (CML). The first patient currently on imatimib mesylate and interferon beta-1a is asymptomatic. For the second patient, interferon beta-1a was withdrawn after suspicion of CML.

Bone ingrowth in macroporous Bonelike for orthopaedic applications

The aim of this study was to evaluate the biological behaviour of porous scaffold structures of Bonelike which is suitable for either direct clinical use or tissue engineering applications. Porous cylindrical specimens 8x10mm were implanted in the lateral aspect of the tibia of 13 patients (mean age 54 years), during osteotomy surgery for the treatment of medial compartment osteoarthritis of the knee. Implanted cylinders were retrieved at the same time as the removal of the blade plates at 3, 6, 9 and 12 months. Scanning electron microscopy and histological evaluations were performed to observe the biological responses of human bone tissue to porous Bonelike. The penetration depth was determined for all implantation periods, and after 6 months it was already possible to see new bone in the centre of the implanted cylinders, which gives 100% of penetration depth for all implantations periods except for 3 months when bone could only be seen in the peripherical region. Regarding the percentage of the area covered by new bone calculated from two-dimensional histological sections, values of 53+/-15, 76+/-12 and 88+/-9% were achieved for 6, 9 and 12 months, respectively. Due to its structural features porous Bonelike permitted effective vascularization and bone ingrowth, and therefore was fully osteointegrated as shown in the histological surveys. A slow biomaterial degradation with implantation time is envisaged since the material has displayed surface degradation. Bonelike scaffolds show potential for complete ingrowth of osseous tissue and restoration of vascularization throughout the defected site.

Dual effect of nitrate therapy for cyclosporine-induced hypertension on vascular and platelet morphofunctional markers; an animal model

The present study sought to evaluate the prevention and reversion effects of isosorbide-5-mononitrate (Is-5-Mn) on the development of hypertension (HT) and on the underlying vascular and platelet morphofunctional disturbances, using an animal model of cyclosporine (CsA)-induced HT. The following rat groups (n = 8) were tested: (1) a control group (orange juice, for 7 weeks); (2) the CsA group (5 mg/kg/d for 7 weeks); (3) the Is-5-Mn group (150 mg/kg/d, twice a day for 7 weeks); (4) the prevention group (Is-5-Mn + CsA) treated for 2 weeks with Is-5-Mn only and thereafter with both drugs for 7 weeks; (5) the curative group (CsA + Is-5-Mn) beginning 7 weeks after CsA and following thereafter with both drugs for 5 weeks. Blood pressure, lipid profile, vascular lesion, platelet aggregation and morphology, and platelet thromboxane A(2)/vascular prostacyclin equilibrium were evaluated. Is-5-Mn + CsA therapy prevented (systolic blood pressure [SBP]: 114.3 +/- 1.9 mm Hg, P < .001; diastolic blood pressure [DBP]: 97.0 +/- 3.3 mm Hg, P < .001) the CsA-induced HT (SBP: 146.2 +/- 4.5 mm Hg, P < .001; DBP: 124.9 +/- 4.5 mm Hg, P < .001 vs control: SBP: 111.6 +/- 0.7 mm Hg; DBP: 94.6 +/- 1.0 mm Hg), as well as the vascular lesion and the platelet morphofunctional disturbances. The curative group did not show attenuated CsA-induced BP increase; it showed further enhancement of the HT effect (SBP: 159.7 +/- 5.5 mm Hg, P < .05; DBP: 132.8 +/- 2.8 mm Hg), as well as worsened vascular lesions and platelet function, namely a disruption in the TXA(2)/PGI(2) equilibrium. Our data suggested that Is-5-Mn therapy may be a valid choice to prevent the morphofunctional changes associated with CsA-induced HT, when used as a preventive therapy. A careful evaluation of the impact of nitrate therapy should be considered, particularly the negative effect on cardiovascular hemodynamics, when considering its use after previous CsA disturbances have been established.

Opening wedge high tibial osteotomy using 3D biomodelling Bonelike macroporous structures: case report

Two synthetic calcium phosphates in porous wedge shape, Bonelike and a commercial HA/beta-TCP biphasic material, were used as an alternative to bone autografts and allografts in the treatment of medial compartment osteoarthritis of varus knees. The structure of Bonelike has a 3D architecture that is computer controlled, and a composition that mimics the mineral composition of natural bone. The HA/beta-TCP biphasic material used as a control material in this study was prepared using conventional foaming based methods. No signs of inflammatory reactions were observed post-operatively for both materials. After 4 months signs of fusion at the osteotomy site and good integration of the implanted wedges were observed, showing good mechanical resistance. Concerning the final correction attained, the left knee revealed a satisfactory valgus of 10 degrees , but the right one only had a final value of 6 degrees . The clinical evaluation using International Knee Score (IKS) showed good outcome in all parameters with complete range of motion in both knees and climbing stairs without crutches with only slight pain.

[Pseudarthrosis of the radius in a child with neurofibromatosis]

In children, pseudarthrosis of the forearm is generally associated to neurofibromatosis. It results from a pathological fracture because it appears in a bone that is considered abnormal for the presence of deformity or cyst. The authors present the case of a child who developed pseudartrosis of the radio after fracture in a bone without structural alteration. Only four similar cases can be found in the literature. The authors discuss its treatment.

Prevalence of asthma-like symptoms by ISAAC video questionnaire in Mozambican schoolchildren

BACKGROUND

The International Study of Asthma and Allergies in Childhood (ISAAC) video questionnaire was developed to overcome the language and cultural differences in the assessment of asthma-like symptoms.

METHODS

27 schools were included in the Maputo Asthma and Allergies in childhood Study (MAPAAS) using ISAAC methods, and a video questionnaire (VQ) was administered to 1614 adolescents 13-14 years old of 20 schools located in urban, suburban and semi-rural areas of Maputo (Mozambique). Simultaneously, they also replied to the ISAAC written questionnaire (WQ).

RESULTS

According to the video questionnaire, the prevalence of current asthma was 11.9% (compared with 13.3% using the written questionnaire). Wheezing after exercise in the last year was reported by about 21%. Females reported more frequent wheezing after exercise than males (p < .001). The prevalence of nocturnal cough in the last year was 24.7%, and was more frequent in the suburban area (p < .001). "Severe attacks of asthma" was reported by 11.9% of the individuals. Teenagers instructed in the suburban schools reported more severe asthma-like symptoms than others (p < .05). There was a poor correlation between the WQ and the AVQ3.0 (kappa coefficients varied from 0.09 to 0.24). The lowest agreement was observed for the question regarding severe attacks of asthma. Agreement was better in terms of specificity than in terms of sensitivity.

CONCLUSIONS

In spite of the poor agreement between the written and the video questionnaires, the prevalence of asthma symptoms estimated using the video questionnaire confirms that asthma is an important public health problem in Maputo.

Asthma and allergies in schoolchildren of Maputo

AIM

The study aimed to determine prevalence and severity of asthma, rhinitis and eczema in Maputo, Mozambique.

METHODS

The International Study of Asthma and Allergies (ISAAC) protocol was applied in 27 schools in urban, suburban and semi-rural areas.

RESULTS

A total of 2630 completed questionnaires were obtained from students aged 13-14 years, and 2383 from schoolchildren aged 6-7 years. The prevalence of current asthma was 13.3% in the two groups, the prevalence of rhinoconjuctivitis and eczema was 23% and 10% in teenagers and 8.8% and 8.5% respectively in children 6-7 years old. Overall, 35% of the adolescents and 23.8% of children were found to have at least one atopic condition or asthma in the last year. In symptomatic adolescents, the conditions were: rhinoconjuctivitis (41.3%), asthma (20%) and eczema (12.4%). In symptomatic children, asthma was the principal condition (36.2%), followed by eczema (20.3%) and rhinoconjunctivitis (19.1%). In adolescents, asthma was more frequently associated with rhinoconjuctivitis (28%). About 4% of all surveyed children had three atopic conditions associated. In adolescents, past year rhinitis was more frequent and severe in the urban area. Hay fever was commoner in the semi-urban area. Eczema was significantly more recurrent in suburban and semi-rural area. Exercise-induced wheeze, nocturnal cough and ever asthma were more reported in children of suburban area.

CONCLUSION

Asthma and allergic diseases are important public health problems in Maputo and improvement in prevention and management plans are required.

[Fracture of the hamate with carpometacarpal dislocation]

Hamate fractures are rare injuries, frequently associated to dislocation of the ring and little fingers at the hamate-metacarpal joint. Its diagnosis is difficult, leading to delays in diagnosis. A strong clinical suspicion and appropriated radiographic exams are essential. The authors present a series of three clinical cases of fracture of the unciforme with carpometacarpal dorsal dislocation of the 4 masculine and 5 masculine fingers. For each case, they discuss the diagnosis, radiographic study, treatment and prognostic.