Volumetric evaluation of fat resorption after breast lipofilling.

INTRODUCTION: The fat transfer or the lipofilling is a technique that had a major impact on the breast surgery results. We have been using this technique since 1998 as an adjuvant in breast reconstruction. The transferred fat is partially resorbed in the first three months after fat grafting. Literature shows that fat resorption varies from 30 to 80% and the experimental studies register a variation between 50 and 90%. The difficulty of the lipomodeling consists in anticipating the fat resorption rate in order to obtain breast symmetry. The purpose of this article is to evaluate the resorption rate of the transferred fat in the reconstructed breast by means of volumetric imaging 3 months after fat grafting. MATERIAL AND METHODS: A prospective study was undertaken including breast reconstructions with total autologous latissimus dorsi. All the surgical procedures have been done by the same surgeon (1st author). It focused on the second stage of breast reconstruction: the lipofilling. We registered the average harvested volumes, the volumes obtained after centrifugation and the transferred volumes for every reconstructed breast. The intramuscular volume in the reconstructed breast was measured by volumetric imaging on the third day after lipofilling (D3) and three months after lipofilling (M3). The volumetry was performed by using an after treatment console SIEMENS (SOMATOM definition AS 2*64 barettes). The average intramuscular volume was registered at D3 and M3. The average volume difference was calculated in order to obtain the exact resorption rate. RESULTS: This prospective study was undertaken on 32 reconstructed breasts by total autologous latissimus dorsi flap. The average age was 52 years, the average BMI was 24.7 kg/m(2). The average harvested fat volume for the breast lipofilling was 560 cc and the volume obtained after centrifugation was evaluated at about 371 cc, the average fat volume transferred being 291 cc. The volumetric study showed that intramuscular volume at D3 was measured at 284 cc and at M3 about 223 cc, of a resorption intramuscular rate of 21.5%. CONCLUSION: In our study, the rate of resorption of the fat transferred to the muscle in the reconstructed breast was measured at 21.5%. The low resorption rate found in our study, lower than those in the literature, sustains the supposition that the muscle is an excellent receiving matrix for the fat tissue. In order to obtain this percentage, a learning curve is necessary. Once acquired, this technique produces a major improvement of the breast surgery results.

[Severe thoracic radionecrosis: muscle-sparing latissimus dorsi flap (MSLD)]. / Radionécrose thoracique sévère : couverture par lambeau avec préservation partielle du latissimus dorsi (PPLD).

INTRODUCTION: Cutaneous radionecrosis and osteoradionecrosis are severe complications of the radiotherapy which can arise after a variable free interval. The loss of substance is frequently associated with a peripheral radiodermatitis and stays an infectious front door exposing patients to a sepsis. The reference treatment remains surgical and consists in realizing the debridment of necrosis tissues associated with flap in order to cover the soft tissus defect. The purpose of our study is to estimate efficiency and tolerance of management radionecrosis thoracique by muscle-sparing latissimus dorsi flap (MSLD). MATERIAL AND METHODS: We realized a study on a series of cases of thoracic radionecrosis with costal exposure covered by MSLD. Fat transfer into peripheral radiodermitis was performed at the same time surgical. Efficiency and tolerance surgery were estimated. The duration of the postoperative antibiotic treatment was estimated. The complications (hematoma, infection, cutaneous suffering, necrosis, seroma, radionecrosis relapse) were screened. The follow-up was realized by the same surgeon. RESULTS: Seven patients managed by the same surgeon were included, They had radionecrosis after radiotherapy for processing adjuvanting of mastectomy after breast cancer. The average age was 66 years (from 61 to 76 years). The average time of hospitalisation was of four days. The average follow-up was of six months. The average treatment of the antibiotic treatment was four weeks. We didn't notice any complications and any recurrence of the radionecrosis. We noticed one dorsal collection (30 cm(3)) 15 days after surgical procedure for one patient. The follow-up showed a stable and good quality cutaneous cover in six months postoperative. CONCLUSIONS: MSLD flap is reliable and reproducible to cover moderate thoracic defect. The surgical parage-wash has a fundamental importance to avoid any infectious complication. The management of the thoracic radionecrosis is complex and multidisciplinary. In conclusion, MSLD flap seems to be an elegant surgical alternative insuring a custom-made optimal cover with a reduction of the morbidity of the site donor.

[Mastoid bone graft in implantology. A case report]. / Greffe d'os mastoïdien en implantologie orale. À propos d'un cas.

INTRODUCTION: In implantology, autogenous bone remains currently a useful-material to rebuild horizontal and vertical osseous defects. Usually, it is the needed osseous volume that indicates the grafting procedure, intraoral one for small and middle volume and extraoral one for severely atrophied jaws. The originality of this case report is to show an alternative to usual grafting procedure borrowed from ENT surgeons: osseous mastoid graft. TECHNICAL NOTE: A 63-year-old patient with maxillary sinus pathology underwent during same surgical time maxillary sinus curetting and osseous grafting to finalize the dental treatment. DISCUSSION: Mastoid cortical bone is a source of bone usable in oral implantology. Its use has been proved to be reliable in oto-surgery. Mastoid bone harvesting implies the presence of ENT surgeon; it is nevertheless interesting to know this site from a biological point of view and because of its functional and economical aspects.

Chromosomal breakpoints characterization of two supernumerary ring chromosomes 20.

The occurrence of an additional ring chromosome 20 is a rare chromosome abnormality, and no common phenotype has been yet described. We report on two new patients presenting with a supernumerary ring chromosome 20 both prenatally diagnosed. The first presented with intrauterine growth retardation and some craniofacial dysmorphism, and the second case had a normal phenotype except for obesity. Conventional cytogenetic studies showed for each patient a small supernumerary marker chromosome (SMC). Using fluorescence in situ hybridization, these SMCs corresponded to ring chromosomes 20 including a part of short and long arms of chromosome 20. Detailed molecular cytogenetic characterization showed different breakpoints (20p11.23 and 20q11.23 for Patient 1 and 20p11.21 and 20q11.21 for Patient 2) and sizes of the two ring chromosomes 20 (13.6 Mb for case 1 and 4.8 Mb for case 2). Review of the 13 case reports of an extra r(20) ascertained postnatally (8 cases) and prenatally (5 cases) showed varying degrees of phenotypic abnormalities. We document a detailed molecular cytogenetic chromosomal breakpoints characterization of two cases of supernumerary ring chromosomes 20. These results emphasize the need to characterize precisely chromosomal breakpoints of supernumerary ring chromosomes 20 in order to establish genotype-phenotype correlation. This report may be helpful for prediction of natural history and outcome, particularly in prenatal diagnosis.

Heart rate as a predictor of energy expenditure in undisturbed fasting and incubating penguins.

Heart rate (f(H)) measurement offers the possibility to monitor energy expenditure (EE) in wild animals if the EE/f(H) relationship for the species, physiological stages and activities of interest is known. This relationship has been extensively studied using oxygen consumption rate ( ) measurement in captive, repeatedly handled king penguins (Aptenodytes patagonicus). Unfortunately, the potential effects of stress on the observed relationships resulting from handling and confinement were not considered. This study is the first involving undisturbed animals, and determines the EE/f(H) relationship in naturally fasting and freely incubating or captivity-acclimatized male and female king penguins. EE determination was based on (1) the measurement of body mass loss during periods of phase II fasting, and (2) the calculation of its energy equivalent from changes in body composition, i.e. 23.9 kJ g(-1). f(H) levels in freely incubating and captivity-acclimatized birds were found to be 50-70% lower than those previously reported for resting king penguins during measurements. Significant EE/f(H) relationships were found in freely incubating and captive males and females (R(2)=0.59 to 0.84), with no difference observed between genders. The best overall relationship was obtained by including fasting duration (t, days) in the model: EE=818+43.7xf(H)+36.3t-1.4txf(H) (R(2)=0.91). This equation yielded EE estimates approximately 26% higher than the previously reported 'best' predictive equation in king penguins, and even more so when f(H) was low. This result suggests that stress induces a disproportionate increase of f(H) vs O(2) consumption, and that the use of EE/f(H) relationships obtained in stressed birds could lead to underestimated EE values.

[Immunization for children travelling to the tropics: neglected vaccines]. / Enfants voyageurs se rendant sous les tropiques: les vaccins négligés.

Each year hundreds of thousands of children leave France to travel to developing countries where they are exposed to infectious agents that can be prevented by vaccination. During the child's pre-travel check-up, practitioners should check that all mandatory immunizations are up-to-date and provide advice on relevant vaccines in function of the epidemiological situation at the chosen destination. However various factors hinder full compliance with this approach and some vaccines are underused. Underused vaccines are referred to as neglected vaccines. In the French vaccination schedule three vaccinations can be considered as neglected. The first is the hepatitis B vaccine that has a low coverage level in France due to strong reluctance to its use despite the fact that the virus is widespread in tropical areas. The second is pneumococcal vaccine that should be administered to all infants less than 2 years of age, especially for travel to areas where pneumonia and meningitis are frequent. The third is BCG vaccine that is now at greater risk of being neglected in child travellers because its use has been downgraded from a general requirement to a recommendation only for children at risk. A serious limitation on the use of travel vaccinations is cost that can lead families to neglect some infectious risk such as hepatitis A that is a major risk for child travellers as well as for their relatives during or after the trip and typhoid fever that is essentially an imported disease. Rabies vaccine is also underused due to its cost and to poor understanding of the risk by many practitioners and families. The purpose of this article is to underline the need to improve information and access to vaccines that are all too often neglected in child travellers.

[Lipomodelling for correction of breast conservative treatment sequelae. Medicolegal aspects. Expert opinion on five problematic clinical cases]. / Lipomodelage et correction des séquelles du traitement conservateur du cancer du sein Aspects médicolégaux. Le point de vue de l'expert à partir de cinq cas cliniques délicats.

In our unit, breast cancer patients suffering mild sequelae of conservative cancer treatment receive fat transfer (lipomodelling), following a precise protocol, based on mammographic and ultrasound examinations and MRI. Available data do not seem to indicate any deleterious impact on patient outcome, notably in view of radiological images, but recurrence (or rather occurrence of new ipsilateral or contralateral cancer) is frequent. The correlation between new or recurrent breast cancer and lipomodelling is high; misinterpretations are possible and frequently arise. The present paper is a description of five complex clinical cases and a discussion of the medicolegal issues that may possibly arise; it also provides tentative expert evaluation of the cases. Clinical findings are reported and analyzed. The second step is a discussion of the radiological impact of lipomodelling, and of the problems caused by the transfer of potentially malignant cells when no preoperative diagnosis of recurrence is made; the morphological and esthetic benefits of the method are described, as well as the potential beneficial impact of fat transfer, notably associated with lower breast density and injections of fat stem cells. Our conclusion is that specialized radiologists, as well as plastic surgery and oncology experts should address the question of fat transfer in operated breast cancer patients and give their reasoned opinion about potentially litigious cases. This would help minimize or solve the conflicts between patients, doctors and experts. Establishing common ground between the different stakeholders would allow the development of the technique, as lipomodelling is, according to our experience, a tremendous advance in the treatment of sequelae from conservative breast cancer surgery.

[Radiological evaluation after lipomodelling for correction of breast conservative treatment sequelae]. / Aspects radiologiques des seins traités par lipomodelage après séquelles du traitement conservateur du cancer du sein.

Breast lipomodelling has been used in our unit since 2002 to correct the sequelae of conservative treatment of cancer. Morphologically, satisfactory results have been recorded and the method is likely to develop considerably. However, the technique has also been questioned because of the possible deleterious radiological impact of injecting fat into the breast. The present work investigated the radiological aspect of conserved breast reconstructed by lipomodelling in a series of 21 patients undergoing ultrasound examination, mammography and MRI, before and after the procedure. Benign-looking microcalcifications were detected on 19% of the mammographies, small (<1cm) oily cysts and complex cysts were visible on respectively 57 and 19% of ultrasound images, whereas 47% of the MRI scans indicated cytosteatonecrotic lesions. Even though multiple events could be observed, their frequency is close to that observed following other conventional breast surgery. Besides, there is clear radiological evidence of benignity. The conclusion of the study is that images obtained after lipomodelling are satisfactory and in no way suggestive of recurrence of breast cancer. Provided that radiologists and experts are aware of this pattern, there is no impact on the radiological follow-up of the patients.

[History of vaccination: from empiricism towards recombinant vaccines]. / Histoire de la vaccination: de l'empirisme aux vaccins recombinants.

PURPOSE: Two hundreds years after the discovery of the smallpox vaccine, immunization remains one of the most powerful tools of preventive medicine. CURRENT KNOWLEDGE AND KEY POINTS: Immunization was born with Jenner, then Pasteur and expanded during the 19th and 20th century. It started with the empirical observation of cross-immunity between two diseases, cowpox and smallpox. It became a real science, with pathogen isolation, culture and attenuation or inactivation, to prepare a vaccine. Together with clinical and biological efficacy studies and adverse events assessments, it constructed the concept of "vaccinology". Protein conjugation of polyosidic vaccines has made possible early immunisation of infants. Nowadays, recombinant, reassortant, or virus-like particles technologies open the road for new vaccines. FUTURE PROSPECTS: Ongoing research opens the way for the development of new vaccines that will help to control transmittable diseases for which we are lacking antimicrobial agents.

[Vaccinations for traveler child]. / Vaccinations de l'enfant voyageur.

Each year, half a million of children leave France to travel towards countries south or east of the European Union, sometimes in poor sanitary conditions. In order to propose essential or useful immunizations for these trips, the current synthesis will allow the practitioner to insure that the routine French immunization schedule has been followed, and to complete it if needed, to protect the child according to the epidemiological situation in the visited area, to try to reduce the limitations of the immunization of the traveler child. In case of emergency, or close departure, it may be useful to follow an accelerated schedule of the last minute, and, sometimes, to immunize traveler children with a chronic disease. Informations on Internet sites useful for the knowledge of current infectious risks in the destination country are also provided.

[Children arthropod bites protective measures: insecticides and repellents]. / Protection antivectorielle de l'enfant: insecticides et insectifuges.

Vector transmitted diseases are often a serious threat for child health, especially for children traveller in tropical regions. Few arthropod borne diseases are preventable by immunization or chimioprophylaxis. Prevention of most of them is based on personal protection against arthropod bites. The evidence of its efficacy has been established by the use of impregnated bed nets, impregnated clothes with permethrin or mosquito repellent which reduced significantly child malaria morbidity and mortality in endemic countries. These personal protective measures are able to minimize arthropod bites and prevent Chikungunya infection, dengue fever and Lyme disease. The choice of a repellent among the commercialised products need to be efficacy and safety evidence based. This article propose to raise this issue and to give pragmatic recommendations, with a focus to children below 30 months who are at a high toxicological risk. Severity of these diseases allowed to use potentially toxic repellents if misused.

[French survey about intradermal BCG SSI adverse events in children under 6 years of age]. / Enquête sur les effets secondaires locaux du vaccin intradermique BCG-SSI chez l'enfant de moins de six ans en France.

During April 2006, 579 physicians took part in a survey about intradermal BCG SSI adverse events (AE) in children less than 6 years old, managed by InfoVac France. Since January 2006, 68% physicians (paediatricians: 73% and general practitioners [GP]: 60%) have vaccinated at least one child. The site of injection is mainly the extern side of the shoulder (72%), according to the recommendations. Systematic vaccination is continued by 54% GP and 26% paediatricians. Others indications are: admission in day care center (33%), admission in day care center associated with risk factors (24%), or only risks factors (8%). Half physicians observed AE and 6% of them reported them at pharmacovigilance centers or pharmaceutical company. AE were mainly inflammations or indurations over 1 cm (for 75% of physicians who observed AE), oozing (73%). Abscesses are notified by 54%, ulcers by 39%, lymphadenopathies over 1 cm by 20%, suppurative lymphadenopathies by 3% and keloid scares by 17% of them, several AE may coexist for some children. Our aim is to start a prospective follow-up of BCG-SSI vaccination and its AE; 58% physicians who answered this investigation agreed to participate.

Impairment in clock-time estimation following right hemisphere ischemic damage.

In order to assess clock-time estimation (CTE), we asked "what time is it in your opinion?" to 48 recent stroke in-patients, 21 with right (RH), 27 with left hemispheric (LH) lesions, and to 20 control in-patients without brain lesions (C). Errors were measured in terms of the number of minutes by which the estimated clock-time was later (advance errors) or earlier (delay errors) than the real clock-time. CTE was considered pathological when exceeding the mean advance or delay errors observed in control patients plus 2.5 standard deviations. The estimation of the duration of a short psychological interview was also assessed. CTE, and not duration estimation, was disturbed in patients. RH patients made significantly more pathological advance errors than LH patients (43% vs. 12%). This study points out the RH dominance for CTE in stroke patients.

Prevalence and trends of infection with Mycobacterium tuberculosis in Djibouti, testing an alternative method.

SETTING: Djibouti, 1994 and 2001. OBJECTIVE: To estimate the prevalence of tuberculosis (TB) and average annual risk of TB infection (ARTI) and trends, and to test a new method for calculations. METHODS: Tuberculin surveys among schoolchildren and sputum smear-positive TB patients. Prevalence of infection was calculated using cut-off points, the mirror image technique, mixture analysis, and a new method based on the operating characteristics of the tuberculin test. Test sensitivity was derived from tuberculin reactions among TB patients and test specificity from a comparison of reaction size distributions among children with and without a BCG scar. RESULTS: The ARTI was estimated to lie between 2.6% and 3.1%, with no significant changes between 1994 and 2001. The close match of the distributions between children tested in 1994 and patients justifies the utilisation of the latter to determine test sensitivity. This new method gave very consistent estimates of prevalence of infection for any induration for values between 15 and 20 mm. Specificity was successfully determined for 1994, but not for 2001. Mixture analysis confirmed the estimates obtained with the new method. CONCLUSION: Djibouti has a high ARTI, and no apparent change over the observation time was found. Using operating test characteristics to estimate prevalence of infection looks promising.

[Action to be taken when facing one or more cases of whooping-cough]. / Conduite à tenir devant un ou plusieurs cas de coqueluche.

The evolution of the epidemiology of pertussis, new licensed macrolides and vaccines, new recommendations for vaccination among adolescents and adults need an update of the French guidelines for prevention of the disease around one or grouped cases of the disease. A particular attention should be raised to the diagnosis of whooping cough in adults who are presently the main reservoir of Bordetella pertussis. Whooping cough in adults presents as an unexplained prolonged cough with nocturnal exacerbation witch accounts for most of the contaminations of young infants. A bacteriological confirmation of pertussis should be provided before implementation of preventive measures: culture and PCR are presently the gold standard for the diagnosis of pertussis in infants, children and even adults who have been coughing for less than 20 days. Later on, serology (Elisa, immuno-empreinte) is the only technique available, but cannot be interpreted if the patient has been vaccinated less than one year ago. Infants under three months should be admitted to hospital and every case submitted to respiratory isolation. Eviction from the community should be pronounced within the five first days following the onset of an effective antibiotic treatment. New macrolides should be favoured: clarithromycin for seven days or azithromycin for five days. Household contacts should be given the same prophylactic antibiotic treatment: children and adolescent not correctly immunized, parents of the index case as adults parents of not or not completely immunized infants. The vaccination program of the household should be updated. The same measures should be applied in case of grouped cases (at least two contemporary or consecutive cases in the same area). In that case, the Public Health System doctors should be involved in the investigation and the classification of the cases. The close contacts not or not completely immunized should be prescribed and antibiotic prophylaxis and an update of their vaccination program. Among the occasional contacts, high-risk people only should be treated. In the day care centres an antibiotic prophylaxis should be given to children who have received less than four vaccine shots against pertussis and to the personnel contact to the cases as well. In the schools, the antibiotic prophylaxis should be prescribed to all children of the classroom(s) not completely vaccinated and to the teacher(s) as well. In the boarding schools and institutions with handicapped children, antibiotic prophylaxis could be applied to every member if the pertussis vaccine coverage is at less than 50%. In hospitals, coughing personnel should wear masks and investigations towards pertussis should be performed in people with a more than seven day unexplained cough. Preventive measures should be applied in case of confirmation of pertussis.

Efficacy of BCG vaccination of the newborn: evaluation by a follow-up study of contacts in Bangui.

BACKGROUND: The efficacy of Bacillus of Calmette and Guérin (BCG) vaccination given at birth is still controversial. We therefore conducted a study in Bangui (Central African Republic) to estimate the protection afforded over the first seven years of life by BCG administered at birth. METHODS: One thousand children who had lived in contact with a recently diagnosed case of contagious tuberculosis were followed up for a period of 6 months in order to detect the occurrence of tuberculosis. Diagnosis of tuberculosis was made through a scoring system. Vaccine efficacy (VE) was calculated on the basis of the relative risk of contracting tuberculosis according to vaccination status. RESULTS: The efficacy of BCG was estimated to be 71% (95% confidence interval: 56-81%). This result remained practically the same after changing the definition used for tuberculosis cases (VE = 75% for a threshold with a score of 15 instead of 6, VE = 74% when only confirmed cases were considered). There was no difference between the two groups in the variables measuring intensity of contact with the source of contamination, but there was a difference in age distribution. Vaccine efficacy adjusted for this factor was the same as the crude VE. CONCLUSION: This study, based on a methodology that controls for most of the risks of bias inherent to field efficacy measurement, confirms the protective capacity of neonatal BCG against childhood tuberculosis. Therefore BCG vaccination at birth must remain a public health priority especially in countries with high incidence of the disease.

PIP: The efficacy of Bacillus of Calmette and Guerin (BCG) vaccination given at birth is still controversial, therefore a study was conducted in Bangui, Central African Republic, to estimate the protection afforded over the first 7 years of life by BCG administered at birth. 1000 children who had lived in contact with a recently diagnosed case of contagious tuberculosis (TB) were followed up from May 1989 to February 1991 in order to detect the occurrence of TB. 896 of them were considered as vaccinated. Diagnosis of TB was made through a scoring system endorsed by the World Health Organization. Contact children with a score of or= 6 were considered to have TB. Four groups of children were formed in order to calculate the risk of TB in relation to vaccination status: children with TB who had been vaccinated, children with TB who had not been vaccinated, healthy children who had been vaccinated, and healthy children who had not been vaccinated. Vaccine efficacy (VE) was calculated on the basis of the relative risk of contracting TB according to vaccination status. Of the 1000 contact children, 91 had a score of or= 6. The TB incidence rate was 7.3% in vaccinated children and 25% in nonvaccinated children, which corresponded to a 0.29 relative risk of contracting TB or efficacy of BCG of 71% (95%, confidence interval: 56-81%). This result remained practically the same after changing the definition used for TB cases (VE = 75% for a threshold with a score of 15 instead of 6, VE = 74% when only confirmed cases were considered). There was no difference between the 2 groups in the variables measuring intensity of contact with the source of contamination, but there was a difference in age distribution. BCG vaccination at birth must remain a public health priority, especially in countries with high incidence of the disease in view of the protective capacity of neonatal BCG against childhood TB.

Altered organ accumulation of oligonucleotides using polyethyleneimine grafted with poly(ethylene oxide) or pluronic as carriers.

Passive targeting provides a simple strategy based on natural properties of the carriers to deliver DNA molecules to desired compartments. Polyethylenimine (PEI) is a potent non-viral system that has been known to deliver efficiently both plasmids and oligonucleotides (ODNs) in vitro. However, in vivo systemic administration of DNA/PEI complexes has encountered significant difficulties because these complexes are toxic and have low biodistribution in target tissues. This study evaluates PEI grafted with poly(ethylene oxide) (PEO(8K)-g-PEI(2K)) and PEI grafted with non-ionic amphiphilic block copolymer, Pluronic P85 (P85-g-PEI(2K)) as carriers for systemic delivery of ODNs. Following i.v. injection an antisense ODN formulated with PEO(8K)-g-PEI(2K) accumulated mainly in kidneys, while the same ODN formulated with P85-g-PEI(2K) was found almost exclusively in the liver. Furthermore, in the case of the animals injected with the P85-g-PEI(2K)-based complexes most of the ODN was found in hepatocytes, while only a minor portion of ODN was found in the lymphocyte/monocyte populations. The results of this study suggest that formulating ODN with PEO(8K)-g-PEI(2K) and P85-g-PEI(2K) carriers allows targeting of the ODN to the liver or kidneys, respectively. The variation in the tissue distribution of ODN observed with the two carriers is probably due to the different hydrophilic-lipophilic balance of the polyether chains grafted to PEI in these molecules. Therefore, polyether-grafted PEI carriers provide a simple way to enhance ODN accumulation in a desired compartment without the need of a specific targeting moiety.

Block and graft copolymers and NanoGel copolymer networks for DNA delivery into cell.

Self-assembling complexes from nucleic acids and synthetic polymers are evaluated for plasmid and oligonucleotide (oligo) delivery. Polycations having linear, branched, dendritic. block- or graft copolymer architectures are used in these studies. All these molecules bind to nucleic acids due to formation of cooperative systems of salt bonds between the cationic groups of the polycation and phosphate groups of the DNA. To improve solubility of the DNA/polycation complexes, cationic block and graft copolymers containing segments from polycations and non-ionic soluble polymers, for example, poly(ethylene oxide) (PEO) were developed. Binding of these copolymers with short DNA chains, such as oligos, results in formation of species containing hydrophobic sites from neutralized DNA polycation complex and hydrophilic sites from PEO. These species spontaneously associate into polyion complex micelles with a hydrophobic core from neutralized polyions and a hydrophilic shell from PEO. Such complexes are very small (10-40 nm) and stable in solution despite complete neutralization of charge. They reveal significant activity with oligos in vitro and in vivo. Binding of cationic copolymers to plasmid DNA forms larger (70-200 nm) complexes. which are practically inactive in cell transfection studies. It is likely that PEO prevents binding of these complexes with the cell membranes ("stealth effect"). However attaching specific ligands to the PEO-corona can produce complexes, which are both stable in solution and bind to target cells. The most efficient complexes were obtained when PEO in the cationic copolymer was replaced with membrane-active PEO-b-poly(propylene oxide)-b-PEO molecules (Pluronic 123). Such complexes exhibited elevated levels of transgene expression in liver following systemic administration in mice. To increase stability of the complexes, NanoGel carriers were developed that represent small hydrogel particles synthesized by cross-linking of PEI with double end activated PEO using an emulsification/solvent evaporation technique. Oligos are immobilized by mixing with NanoGel suspension, which results in the formation of small particles (80 nm). Oligos incorporated in NanoGel are able to reach targets within the cell and suppress gene expression in a sequence-specific fashion. Further. loaded NanoGel particles cross-polarized monolayers of intestinal cells (Caco-2) suggesting potential usefulness of these systems for oral administration of oligos. In conclusion the approaches using polycations for gene delivery for the design of gene transfer complexes that exhibit a very broad range of physicochemical and biological properties, which is essential for design of a new generation of more effective non-viral gene delivery systems.

Diurnal changes in psychophysiological variables of school girls: comparison with regard to age and teacher's appreciation of learning.

Ninety-five nonresident girls of a private school volunteered for the study with the teachers' help as well as parental consent. Ages were approximately 8, 9, and 10 years. They were synchronized with diurnal activity from 0730 to 2100 h and nocturnal rest. Fatigue, drowsiness, and attention were self-rated using visual analogue scales; oral temperature was self-measured and a letter cancellation test was performed. Each of these variables was measured at school at 0900, 1100, 1400, and 1600 h on Mondays, Thursdays, Fridays, and Saturdays for two consecutive weeks in 1987 (March 30-April 11) and again in 1989 (March 13-25) when the youngest group had become 10 years old. According to conventional teacher evaluation of learning (learning performance) within each group, three subgroups were formed: top third, middle third, and bottom third. Time series (more than 50,000 data) were analyzed according to several statistical methods, but mainly chronograms with ANOVA. Similar diurnal changes in oral temperature were validated for each group and subgroups. The occurrence of a diurnal change in self-rated variables (fatigue and drowsiness) and score in letter cancellation was age related: no detection in the 8-year-old group (and subgroups) and validation (p less than 0.002) in 9- and 10-year-old groups (and respective subgroups). A good learning performance was associated with a reduced drowsiness in school girls of 9 and 10 years. Age-related, time-of-day differences in drowsiness (when detected) as well as learning performance effect were not associated with observed duration of sleep. Validated changes in self-rated fatigue were close to that of drowsiness. At 0900 h, girls of 9 and 10 years were more tired when belonging to the bottom third than top third subgroup. Whatever the time of day, self-rated attention was greater in the top than in the bottom third for these girls. Differences related to learning performance were validated in each grade. However, best scores were recorded for the bottom third in the 8-year-old group, while best scores were provided by top third subgroups in 10-year-old girls. It seems that in girls around 8 years of age, critical changes can be detected with regard to the (ontogenic?) occurrence of time-of-day differences in a set of psychophysiologic variables as well as influential effects of learning performance on the same variables. Reported finding are compatible with the hypothesis of circadian oscillators working at the level of the cortex of the human brain.