Osmotic shrinkage in star/linear polymer mixtures

Multiarm star polymers were used as model grafted colloidal particles with long hairs, to study their size variation due to osmotic forces arising from added linear homopolymers of smaller size. This is the origin of the depletion phenomenon that has been exploited in the past as a means to melt soft colloidal glasses by adding linear chains and analyzed using dynamic light scattering experiments and an effective interactions analysis yielding the depletion potential. Shrinkage is a generic phenomenon for hairy particles, which affects macroscopic properties and state transitions at high concentrations. In this work we present a small-angle neutron scattering study of star/linear polymer mixtures with different size ratios (varying the linear polymer molar mass) and confirm the depletion picture, i.e., osmotic star shrinkage. Moreover, we find that as the linear/star polymer size ratio increases for the same effective linear volume fraction (c/c* with c* the overlapping concentration), the star shrinkage is reduced whereas the onset of shrinkage appears to take place at higher linear polymer volume fractions. A theoretical description of the force balance on a star polymer in solution, accounting for the classic Flory contributions, i.e. elastic and excluded volume, as well as the osmotic force due to the linear chains, accurately predicts the experimental findings of reduced star size as a function of linear polymer concentration. This is done in a parameter-free fashion, in which the size of the cavity created by the star, and from which the chains are excluded, is related to the radius of the former from first principles.

Is the high submandibular transmasseteric approach to the mandibular condyle safe for the inferior buccal branch?

PURPOSE

There are basically 3 main approaches for extra-articular mandibular condyle fractures: low cervical, retromandibular and preauricular. These include a risk of facial palsy affecting the marginal mandibular branch. We use a high submandibular transmasseteric approach featuring masseter section 10-20 mm above the mandibular basilar edge. Our null hypothesis was that both the marginal mandibular and the inferior buccal branches are not more at risk than in other surgical approaches.

METHODS

This study was based on 20 parotidomasseteric dissections from 10 embalmed cadaveric heads. We used as reference the vertical line, passing through the mandibular angle, parallel to the preauricular line. We performed measurements of the marginal mandibular and inferior buccal branches' heights.

RESULTS

The inferior buccal branch had an average height of 16.8 mm and the highest standard deviation (7.2). Extremes were, respectively, 32 and 7 mm. The marginal mandibular branch had an average height of 3.2 mm with standard deviation equal to 3.0. Extremes were, respectively, 9 and -3 mm.

CONCLUSION

The high submandibular transmasseteric approach provides great exposure of facial nerve branches lying on the masseter muscle, if even encountered. Through masseteric incision performed between 10 and 20 mm above the basilar edge of the mandible, the marginal mandibular branch is safe from wound with an added safety margin of 4 mm. The surgeon using this approach is most likely to encounter the inferior buccal branch. It can then be avoided under visual control. This makes it a swift and safe approach to the mandibular condyle.

Slow dynamics, aging, and crystallization of multiarm star glasses

Multiarm star polymers are model systems with tunable intermediate colloid to polymerlike character, exhibiting rich phase behavior, internal relaxations, and flow properties. An important puzzle for several years has been the lack of clear experimental proof of crystalline states despite strong theoretical predictions. We present unambiguous evidence via multispeckle dynamic light scattering (MSDLS) and small-angle neutron scattering (SANS) for such crystallization in a solvent of intermediate quality. An unexpected speed up of the short-time star diffusion observed in MSDLS was attributed by SANS to crystallization, via aging, of the multiam star glass. This delayed glass to crystal transition establishes a pathway for star crystallization that might be generic in colloidal glasses.

Assessment of co-existence of Helicobacter pylori and Candida fungi in diseases of the upper gastrointestinal tract

Candida spp. were found in the gastric mucosa of 27 (17%) patients, out of whom 18 (11%) showed co-existence of the fungi with H. pylori. Analysis of relationship between selected disorders of the upper gastrointestinal tract (non ulcer dyspepsia NUD, gastric ulcer, duodenal ulcer) and infection with H. pylori and/or Candida revealed a link between co-existence of H. pylori with Candida and gastric ulcers suggesting synergism of those microorganism in pathogenesis of the disease. On the contrary, according to quantitative studies performed, the fungi alone do not play a significant role in pathogenesis of the above mentioned disorders as they colonize only epithelium to the extent that is not pathologically significant (<10(3) CFU/ml). Genetical study was carried out on 57 Helicobacter pylori strains isolated from bioptates of the gastric mucosa. The genotypes of the strains (gene cagA and alleles of gene vacA - m1, m2, s1, s2) were determined using the PCR technique. As it was shown, the patients infected with H. pylori strains of genotype cagA+, vacA s1 are exposed to higher risk of peptic ulcer disease (PUD) as compared to the patients infected with cagA-, vacA s2 strains. In the case of the NUD patients a correlation with allele m2 was found only (p<0.001). This may suggest that in future some of the NUD patients infected with cagA+, vacA s1 strains will fall into the group at higher risk for PUD.

Structure and phase diagram of an adhesive colloidal dispersion under high pressure: a small angle neutron scattering, diffusing wave spectroscopy, and light scattering study

We have applied small angle neutron scattering (SANS), diffusing wave spectroscopy (DWS), and dynamic light scattering (DLS) to investigate the phase diagram of a sterically stabilized colloidal system consisting of octadecyl grafted silica particles dispersed in toluene. This system is known to exhibit gas-liquid phase separation and percolation, depending on temperature T, pressure P, and concentration phi. We have determined by DLS the pressure dependence of the coexistence temperature and the spinodal temperature to be dP/dT=77 bar/K. The gel line or percolation limit was measured by DWS under high pressure using the condition that the system became nonergodic when crossing it and we determined the coexistence line at higher volume fractions from the DWS limit of turbid samples. From SANS measurements we determined the stickiness parameter tau(B)(P,T,phi) of the Baxter model, characterizing a polydisperse adhesive hard sphere, using a global fit routine on all curves in the homogenous regime at various temperatures, pressures, and concentrations. The phase coexistence and percolation line as predicted from tau(B)(P,T,phi) correspond with the determinations by DWS and were used to construct an experimental phase diagram for a polydisperse sticky hard sphere model system. A comparison with theory shows good agreement especially concerning the predictions for the percolation threshold. From the analysis of the forward scattering we find a critical scaling law for the susceptibility corresponding to mean field behavior. This finding is also supported by the critical scaling properties of the collective diffusion.

[Calvarial bone grafting in augmentation rhinoplasty. Long-term results]

INTRODUCTION

Various clinical situations may require an important increase of the size of the nose. The aim of our work was to analyze long-term results of calvarial bone grafts used in rhinoplasties.

MATERIAL AND METHOD

We retrospectively studied the files of 20 patients having undergone a calvarial bone graft. Photogrammetry was used to determine morphological modifications and the stability of results.

RESULTS

The average follow-up was 8 years. The parietal donor site morbidity was low. All nose sizes were dramatically augmented and the stability of results ranged between 74.5 and 95%.

DISCUSSION

The calvarial bone graft can be used for important nose augmentation with a good stability. There are few alternative techniques. This method is only limited by available skin and endonasal lining. Calvarial bone graft in rhinoplasty is not frequent but it is our first choice for the correction of important hypoplasia or saddling of the nose.

[Massage of the lateral pterygoid muscle in acute TMJ dysfunction syndrome]

INTRODUCTION

Massage of the lateral pterygoid muscle according to Cyriax's principles is an unrecognized procedure. This procedure was tried on patients presenting with temporomandibular joint dysfunction syndrome.

MATERIAL AND METHODS

Fifteen patients were treated. Pain, joint clicking, measurement of mouth opening, lateral excursion and propulsion were recorded. Assessment was made before and after the massage in the same consultation.

RESULTS

Joint clicking was solved in 80% and pain in 50% of the cases. Mouth opening increased by 12.8%, propulsion by 11.6% and lateral excursion by 41.3%.

DISCUSSION

Massage of the lateral pterygoid muscle according to Cyriax's principles is a simple and efficient method that can be recommended for patients presenting with temporomandibular joint dysfunction syndrome. We performed a brief anatomical and radiological MRI study supporting the feasibility of lateral pterygoid muscle palpation.

[Postoperative intraorbital haematoma with septicemia due to Methylbacterium mesophilicum: a rare cause. Case report]

INTRODUCTION

Compressive-orbital haematoma is a rare, but dreaded, complication in facial traumatology.

OBSERVATION

The authors report a case of postoperative blindness after a delayed procedure for an orbit-floor fracture, complicated by Methylbacterium mesophilicum septicemia. Three surgical procedures were performed, simple drainage, down fracture of the orbit floor, and osteotomy of the zygoma, without any improvement.

DISCUSSION

The role of M. mesophilicum in a major coagulation deficiency is discussed. Decompressive-orbital procedures are reviewed and discussed for this special case.

Deoxyribonucleoside phosphoramidites

The detailed preparation of deoxyribonucleoside phosphoramidites bearing a 4-[N-methyl-N-(2,2,2-trifluoroacetyl)amino]butyl group for P(III) protection is presented. The use of this group circumvents nucleobase alkylation during oligonucleotide deprotection. Two syntheses of phosphoramidites starting from either a phosphordichloridite precursor or a bis-(N,N-diisopropylamino)chlorophosphine intermediate are described for the phosphinylation of suitably protected deoxyribonucleosides.

[Fat tissue transplant: restoration of the mammary volume after conservative treatment of breast cancers, clinical and radiological considerations]

The aim of this study is to evaluate fat tissue graft as a treatment of sequelae of breast cancer conservative surgery.

MEANS AND METHODS

This prospective study during a nine-month period concerned 15 patients with breast cancer conservative treatment sequelae. Fat tissue has been injected at the site where the tumorectomie and subsequent radiotherapy had been performed. A mammographic and photographic checkup along with the patients' subjective evaluation were done before the operation and after the operation with a one-month, three-month, and nine-month follow-up. An objective analysis of the results was done by a panel from the pictures of the ninth month's follow-up. Preoperative and postoperative mammary volumes were calculated by a CT scan using a 3D program.

RESULTS

Mean fat tissue injected was 63.3cc. Mean patients' satisfaction grade was 8.1/10 at one month and 6.7/10 at nine months. The estimation of the resorption at nine months was 52.6% according to the patients while announced at 47.5% with the CT scan. Eighty percent of patients estimated the operation as "light" and 60% would be ready to have another injection. Skin tissue quality was enhanced and only one infection has been stated. Two-thirds of postoperative mammographies are still ACR 2 and one-third of the patients have had cytosteatonecrosis.

CONCLUSION

This fat tissue graft technique on irradiated skin for the correction of tumorectomy sequelae brings a simple and efficient solution, which is radiologically reliable and satisfying for the patients.

[Reconstruction of the nasal alar defect with the superiorly based nasolabial flap described by Burget: report of seven cases]

BACKGROUND

The reconstitution of a nasal alar rim and lobule defect represent a difficult challenge in consideration of his situation, anatomy and function. This article describes the technique and the interest of the nasolabial flap when used to cover the entire alar subunit.

METHODS

We present 7 cases of alar rim and lobule defect after skin cancer excision. In the series, there are two full-thickness with lining defect. The patients were reconstructed with a superiorly based nasolabial flap, according to the subunit principle as introduced by Burget. A free cartilage graft was used to restore structural support with marginal skin flaps were turned over for intranasal lining when necessary.

RESULTS

The cosmetic and functional outcomes of each repair were judged from good to excellent by patients and surgeons. No case of flap infection or necrosis occurred.

CONCLUSION

The superiorly based nasolabial flap, describe by Burget, provides an excellent choice for cosmetic and functional reconstruction of the nasal alar defect.

Diffusion of spheres in isotropic and nematic networks of rods: electrostatic interactions and hydrodynamic screening

Translational diffusion of a small charged tracer sphere in isotropic and nematic suspensions of long and thin charged rods is investigated as a function of ionic strength and rod concentration. A theory for the diffusive properties of a small sphere is developed, where both (screened) hydrodynamic interactions and charge interactions between the tracer sphere and the rod network are analyzed. Hydrodynamic interactions are formulated in terms of the hydrodynamic screening length. As yet, there are no independent theoretical predictions for the hydrodynamic screening length for rod networks. Experimental tracer-diffusion data are presented for various ionic strengths as a function of the rod concentration, both in the isotropic and nematic states. Orientational order parameters are measured for the same ionic strengths as a function of the rod concentration. The hydrodynamic screening length is determined from these experimental data and scaling relations obtained from the above mentioned theory. For the isotropic networks, a master curve is found for the hydrodynamic screening length as a function of the rod concentration. For the nematic networks the screening length turns out to be a very sensitive function of the orientational order parameter.

Dégénérescence de maladie de Verneuil en carcinome épidermoïde : à propos de 2 cas et revue de la littérature

Verneuil's disease (hidradenitis suppurativa) is a chronic inflammatory, suppurating, fistulizing and scar-producing disease of apocrine gland-bearing skin. Its transformation into epidermoid carcimona has been reported 38 times in literature. We describe two new cases - two males aged 67 and 68-years-old. The first one is still alive with no recurrence after one year and the second patient died 2 months after surgery, showing generalised scattering. This rare complication is interesting for two reasons. It only concerns perianal location and it targets mainly men. Surgical treatment consists of wide excision. However, it is often too late. The outcomes are critical for it has been reported a 50% rate of deaths within 2 years after surgery. It is therefore imperative that both general practitioners and dermatologists follow patients with Verneuil's disease so that they can propose a preventive excision at the right time.

Diffusion of spheres in isotropic and nematic suspensions of rods

Diffusion of a small tracer sphere (apoferritin) in isotropic and nematic networks [of fd virus] is discussed. For a tracer sphere that is smaller than the mesh size of the network, screened hydrodynamic interactions between the sphere and the network determine its diffusion coefficient. A theory is developed for such interactions as well as their relation to the long-time self-diffusion coefficient. Fluorescence correlation spectroscopy measurements on mixtures of apoferritin and fd virus are presented. The long-time self-diffusion coefficient of apoferritin is measured as a function of the fd-virus concentration, both in the isotropic and nematic state, in directions parallel and perpendicular to the nematic director. The hydrodynamic screening length of the fd-virus network as a function of fd concentration is obtained by combining these experimental data with the theory. Surprisingly, the screening length increases with increasing concentration in nematic networks. This is due to the increase in the degree of alignment, which apparently leads to a strong increase of the screening length. Hydrodynamic screening is thus strongly diminished by alignment. A self-consistent calculation of the screening length does not work at higher concentrations, probably due to the strong variation of the typical incident flow fields over the contour of a rod.

Diffusion and microstructural properties of solutions of charged nanosized proteins: Experiment versus theory

We have reanalyzed our former static small-angle x-ray scattering and photon correlation spectroscopy results on dense solutions of charged spherical apoferritin proteins using theories recently developed for studies of colloids. The static structure factors S(q), and the small-wave-number collective diffusion coefficient D(c) determined from those experiments are interpreted now in terms of a theoretical scheme based on a Derjaguin-Landau-Verwey-Overbeek-type continuum model of charged colloidal spheres. This scheme accounts, in an approximate way, for many-body hydrodynamic interactions. Stokesian dynamics computer simulations of the hydrodynamic function have been performed for the first time for dense charge-stabilized dispersions to assess the accuracy of the theoretical scheme. We show that the continuum model allows for a consistent description of all experimental results, and that the effective particle charge is dependent upon the protein concentration relative to the added salt concentration. In addition, we discuss the consequences of small ions dynamics for the collective protein diffusion within the framework of the coupled-mode theory.

Self-diffusion in solutions of a 20 base pair oligonucleotide: Effects of concentration and ionic strength

The long-time self-diffusion coefficients of a 20 base pair duplex oligonucleotide are measured as functions of 20-mer and added NaCl salt concentrations. The self-diffusion coefficients decrease monotonically with increasing 20-mer concentrations for the high-added salt sample and display non-monotonically decreasing 20-mer concentration dependences at lower added salt concentrations. The non-monotonic behavior is attributed to the opposing effects of the tendency to increase the interactions between 20-mers as the concentration is increased and to a decrease in the extent of the Coulomb forces as counterions from the 20-mer increasingly screen them. Attempts to account for the effect of the Coulomb forces on the self-diffusion coefficients by using effective dimensions in the hard rod theory give good agreement with experiment at the highest salt concentration studied. For the lower salt concentrations there appear to be two scaling regimes--one at low polyion concentration in which the high salt scaling of the rod dimensions by adding the Debye screening to the length and diameter of the rod is appropriate and one at high polyion concentrations where the scaling of the dimensions is the addition of 1/2 the Debye screening length. Estimates of the "overlap" concentration C*=1/L(eff) indicate that the non-monotonic decrease occurs at concentrations lower than C*. Finally, the fluorescence correlation spectroscopy self-diffusion coefficients measured here are compared with the mutual diffusion coefficients measured by dynamic light scattering.

Conceptual "Heat-Driven" approach to the synthesis of DNA oligonucleotides on microarrays

The discovery of deoxyribonucleoside cyclic N-acylphosphoramidites, a novel class of phosphoramidite monomers for solid-phase oligonucleotide synthesis, has led to the development of a number of phosphate protecting groups that can be cleaved from DNA oligonucleotides under thermolytic neutral conditions. These include the 2-(N-formyl-N-methyl)aminoethyl, 4-oxopentyl, 3-(N-tert-butyl)carboxamido-1-propyl, 3-(2-pyridyl)-1-propyl, 2-[N-methyl-N-(2-pyridyl)]aminoethyl, and 4-methythiobutyl groups. When used for 5'-hydroxyl protection of nucleosides, the analogous 1-phenyl-2-[N-methyl-N-(2-pyridyl)]aminoethyloxycarbonyl group exhibited excellent thermolytic properties, which may permit an iterative "heat-driven" synthesis of DNA oligonucleotides on microarrays. In this regard, progress has been made toward the use of deoxyribonucleoside cyclic N-acylphosphoramidites in solid-phase oligonucleotide syntheses without nucleobase protection. Given that deoxyribonucleoside cyclic N-acylphosphoramidites produce oligonucleotides with heat-sensitive phosphate protecting groups, blocking the 5'-hydroxyl of these monomers with, for example, the thermolabile 1-phenyl-2-[N-methyl-N-(2-pyridyl)]aminoethyloxycarbonyl group may provide a convenient thermo-controlled method for the synthesis of oligonucleotides on microarrays.

Familial cylindromatosis

Familial cylindromatosis: we report a daughter with turban tumor and her mother with cylindromatosis. The dermal eccrine cylindroma arose as small, solitary lesions on the head of the mother when she was 28 years old. The following years other tumors became apparent. She was operated on several times. The first lesions appeared on the frontal part of the scalp of the daughter when she was 23 years old. Other tumors grew on the scalp. Histopathological examination of the excised tumors showed the same lesions in both the mother and the daughter: dermal eccrine cylindromata. Family history showed that the daughter's maternal aunt had a few tumors. Dermal eccrine cylindroma should be differentiated from malignant syndromes such as basal naevoid carcinoma or metastases and from neurofibromata. The gene of familial cylindromatosis was localised to chromosome 16q12-q13 and it was proposed that this gene is a tumor supressor gene.

Inhibition of potentially anti-apoptotic proteins by antisense protein kinase C-alpha (Isis 3521) and antisense bcl-2 (G3139) phosphorothioate oligodeoxynucleotides: relationship to the decreased viability of T24 bladder and PC3 prostate cancer cells

Isis 3521 and G3139 are 20- and 18-mer phosphorothioate oligonucleotides, respectively, targeted to the protein kinase C (PKC)-alpha and bcl-2 mRNAs. Treatment of T24 bladder and PC3 prostate carcinoma cells with full-length and 3'-truncation mutants of Isis 3521 causes down-regulation of PKC-alpha protein and mRNA. However, at the level of a 15-mer and shorter, down-regulation of mRNA expression is no longer observed. Further, no diminution in cellular viability, as measured by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide assay, in response to increasing concentrations of paclitaxel, can be observed for these shorter oligomers. These observations not only indicate that PKC-alpha protein expression can be down-regulated by both RNase H-dependent and -independent mechanisms but also that down-regulation of PKC-alpha is insufficient by itself to "chemosensitize" cells. G3139, which down-regulates bcl-2 protein and mRNA expression, also down-regulates PKC-alpha protein and mRNA expression but not that of PKC-betaI, -epsilon, or -zeta. However, the down-regulation of PKC-alpha and bcl-2 are not linked. When the carrier Eufectin 5 is employed, only bcl-2 is down-regulated in both T24 and PC3 cells at 50 nM oligonucleotide concentration. At 100 nM, both bcl-2 and PKC-alpha expression are down-regulated, and only at this concentration can "chemosensitization" to paclitaxel and carboplatin be observed. In contrast, the down-regulation of bcl-2 seems to be linked with that of RelA (p65). However, this too is also not sufficient for chemosensitization, even though it leads to the loss of expression of genes under the putative control of nuclear factor-kappaB and to detachment of the cells from plastic surfaces. These results underscore the complexity of the intracellular requirements for the initiation of chemosensitization to anti-neoplastic agents.

The 2-(N-formyl-N-methyl)aminoethyl group as a potential phosphate/thiophosphate protecting group in solid-phase oligodeoxyribonucleotide synthesis

[reaction in text] The 2-(N-formyl-N-methyl)aminoethyl deoxyribonucleoside phosphoramidite 1 has been synthesized and used in the solid-phase synthesis of an octadecathymidylic acid as a cost-efficient monomer for potential application in the preparation of therapeutic oligonucleotides. The 2-(N-formyl-N-methyl)aminoethyl group can be cleaved from oligonucleotides according to a unique thermolytic cyclodeesterification process at pH 7.0. In addition to being cost-effective, the use of 1 simplifies oligonucleotide postsynthesis processing by eliminating the utilization of concentrated ammonium hydroxide in oligonucleotide deprotection.

Infants' long-term memory for a serial list: recognition and reactivation

Serial lists contain information about item identity and item order. Using a task designed for nonverbal animals, we previously found that 3- and 6-month-olds exhibited a primacy effect after 24 hr, remembering both item identity and item order. Presently, we examined their memory of list information after longer delays. In Experiment 1, the serial-position curve reverted to a U-shape after 1 week at both ages, revealing that the common practice of attributing primacy and recency effects to long- and short-term memory, respectively, is flawed. In Experiment 2, a precuing procedure confirmed that 6-month-olds' memory still contained order information after 1 week, but 3-month-olds' reactivated memory contained none. Experiments 3A and 3B confirmed that increasing the complexity of information that was learned shortened the delay after which it could be retrieved. Testing infants after delays longer than have previously been used with animals or human adults sheds new light on an old phenomenon.

Development of a static simulator of the mandible

Our aim was to build and assess a static mandibular simulator capable of reproducing various masticatory exercises as closely as possible to physiological situations. Unlike existing devices that reproduce a small number of exercises and of muscular bundles, our simulator is able to reproduce all types of effort in the sagittal plane and integrates eleven muscular groups considered by the majority of authors as being the most important in mastication. The value of our simulator arises from its ability to replicate the external forces (including muscular traction, intra-articular reaction and resultant forces applied to the mandible) as determined in vivo during previous studies. The importance of such a versatile simulator, in addition to enabling study of the mechanical behaviour of the mandible, is that it greatly enhances evaluation of a possible mathematical model by means of finite element analysis. Stages of the development and evaluation of this device are described.

Mandibular pseudocarcinomatous hyperplasia

AIMS

Three unusual cases of pseudocarcinomatous (pseudoepitheliomatous) hyperplasia (PH) affecting chronic osteomyelitic mandibular sequestra are reported to highlight the differences with the various squamous neoplasms which occur in that site.

METHODS AND RESULTS

In two patients carrying a mandibular graft following the excision of an ameloblastoma, mucosal ulcers resulted in chronic osteomyelitis. In a third patient, an apical dental infection was associated with fistulated osteomyelitis. Histology of the three sequestra showed an intraosseous squamous proliferation. It was characterized by a peripheral involvement of medullary spaces, the more mature epithelial layer covering the bone trabeculae without intervening stroma, and the basal type epithelial layer surrounding a central fibrovascular core. There were no histological or cytological signs of malignancy.

CONCLUSION

PH shows an inverted pattern when compared with the centro-medullary tumoural islands seen in the various oral or odontogenic squamous neoplasms which occur in the jaws. The lack of signs of malignancy distinguish PH from common squamous cell carcinomas. A short clinical course is an important feature in the distinction of PH from the well differentiated squamous cell carcinomas which may develop in fistulated chronic osteomyelitis.

Reinstatement versus reactivation effects on active memory in infants

Reinstatement and reactivation are procedurally different reminder paradigms used with infants and children, but most developmental psychologists do not distinguish between them. In 4 experiments with 102 three-month-olds, we asked if they differ functionally as well. Independent groups of infants received either a reactivation or a reinstatement reminder 3 days after training, when the memory is active, but its specific details have been forgotten. In Experiment 1, we measured retention after increasing delays until infants forgot altogether. A single reinstatement protracted retention twice as long after training as a single reactivation. In Experiments 2-4, whether the reminder was the original training stimulus or a novel one differentially affected the duration and specificity of memory in the 2 procedures as well. These data demonstrate that the distinction between reinstatement and reactivation is not artificial. In addition to differing procedurally, reinstatement and reactivation differ functionally, with different memory-preserving effects.

Biodegradation in laboratory activated sludge plants and aquatic toxicity of herbicides

The biodegradation and the aquatic toxicity of four herbicides (isoproturon, terbuthylazine, mecoprop, metamitron) were investigated. Laboratory activated sludge plants were used for biodegradation experiments. The biodegradation of mecoprop reached nearly 100%, the other herbicides were not eliminated by biodegradation. The acute Daphnia magna 24-h assay, the algal 72-h inhibition test, and the recently developed lemna growth inhibition 7-d test were applied to evaluate the biological effects of herbicides as original substances. EC 50 and EC 10 values were determined. Algal and lemna test show that isoproturon and terbuthylazine are both much more toxic than mecoprop and metamitron. Daphnids are generally less sensitive against herbicides than plants. Biodegradation and toxicity test were coupled for mecoprop to assess biological long-term effects of possible biodegradation products of this herbicide. The effluents of the laboratory activated sludge units were used in toxicity tests (Daphnia magna 21-d reproduction test, lemna growth inhibition 7-d test). No inhibiting effect on the tested organisms was observed.

[Long-term outcome of surgically treated orbital floor fractures. Apropos of a series of 242 patients]

Over a period extending from January 1993 to December 1995, we treated 242 patients with 268 orbital floor fractures in our department. Surgical indications were broad and relied on clinical criteria (enophthalmos, diplopia, hypoesthesia) and/or CT analysis (bony collapse, extrusion of orbital contents, suspicion of muscular entrapment, dislocation of the infraorbital rim). Two years after surgery, 91% of the patients showed good results (absence of diplopia or severe enophthalmos). The analysis of these results points out that the degree of sequelar enophthamos was not only related to the degree of initial bony collapse but above all to the quality of the bony reconstruction. Sequelar diplopia was linked with the presence of a preoperative diplopia and its severity was a direct function of operative delay. Hypoesthesia in the infraorbital nerve territory was the most common sequela; some were postoperative complications. The type of material used for the restoration of the orbital floor was not involved in the development of these sequela. Our good results suggest that an interventionist attitude is warranted in these kind of fractures, the more so as the X-ray examinations often underestimate injuries.

Determination of the external forces applied to the mandible during various static chewing tasks

The purpose of this study is to determine the external forces that are brought to bear on the mandible during 14 masticatory tasks, exerted in three defined mandibular positions. A static two-dimensional mandibular model is presented, taking into account projections in the sagittal plane of the forces exerted by six muscle groups and the joint reaction force. In calculating these external forces, two working hypotheses are adopted: the existence of a linear relationship between cross-sectional surface of the muscle and its maximum force of contraction, and the existence of a linear relationship between the electrical signal emitted by a muscle and the force the muscle then develops. Our first results are provided and compared with data from the literature. Individual variations recorded in the measurement of the different parameters involved in the equilibrium equations are such that they must be taken into account in the calculation of the forces. Moreover, the functional value of the muscles appears to be closely dependent on the mandibular position with which they are associated, which is not brought out in earlier studies. Finally, intra-joint action proves to be intense, although its direction varies according to the mandibular position and the type of exercise performed.

[Methods proposed for the determination of external forces applied to the mandible during mastication. Initial results]

The purpose of this study is to determine the external forces that are brought to bear on the mandible during various masticatory exercises. An analysis is presented of a static two-dimensional mandibular model taking into account projections in the sagittal plane of the forces exerted by six muscle groups and the joint reaction. In calculating the external forces, two working hypotheses are adopted: the existence of a linear relationship between cross-sectional surface of the muscle and its maximum force of contraction; the existence of a linear relationship between the electrical signal emitted by a muscle and the force the muscle then develops. It follows that, in order to calculate, the muscle forces, there is a need to measure the intensity of masticatory effort, the cross-sectional surface and the electromyographic activity of the different muscles involved. These values are then used for working out the equations of equilibrium. Results are provided for 14 masticatory exercises effected in three different mandibular positions and compared with data from literature. Individual variations recorded in the measurement of the different parameters involved in the equilibrium equations are such that they must be taken into account for the calculation of the forces. Moreover, the functional value of the muscles appears to be closely dependent on the mandibular position with which they are associated, which is not brought out in earlier studies. Finally, intra-joint action proves to be intense, although its direction varies according not only to the mandibular position but also the type of exercise performed.

[Combined Latissimus dorsi and Serratus anterior reverse flow pedicle flap. Report of a clinical case]

The authors report a new local combined flap involving the distally based Latissimus dorsi muscle pedicled on the lumber perforating arteries and prolonged by the last three digitations of the Serratus anterior muscle supplied by the thoracic branch of the thoraco-dorsal artery. This artifice, never previously described, increased the bulk and arc of rotation of the dorsalis flap. It was thus possible to cover a wide defect on the posterior aspect of the sacro-iliac region in a patient previously operated for a highly malignant histiocytofibroma. The anatomic considerations, harvesting technique and advantages and drawbacks of this flap are discussed.

The effect of two antipodal fluorine-induced sugar puckers on the conformation and stability of the Dickerson-Drew dodecamer duplex [d(CGCGAATTCGCG)]2

UV thermal melting studies, CD and NMR spectroscopies were employed to assess the contribution of antipodal sugar conformations on the stability of the canonical B-DNA conformation of the Dickerson-Drew dodecamer duplex [[d(CGCGAATTCGCG)]2, (ODN 1)]. Different oligodeoxynucleotide versions of ODN 1 were synthesized with modified thymidine units favoring distinct sugar conformations by using a 3'- endo (north) 2'-fluoro-2'-deoxyribofuranosyl thymine (1) or a 2'- endo (south) 2'-fluoro-2'-deoxyarabinofuranosyl thymine (2). The results showed that two south thymidines greatly stabilized the double helix, whereas two north thymidines destabilized it by inducing a more A-like conformation in the middle of the duplex. Use of combinations of north and south thymidine conformers in the same oligo destabilized the double helix even further, but without inducing a conformational change. The critical length for establishing a detectable A-like conformation in the middle of a B-DNA ODN appears to be 4 bp. Our results suggest that manipulation of the conformation of DNA in a sequence-independent manner is possible.

[Osteosynthesis of subcondylar fractures using a rectangular 3-dimensional stabilization plate]

The current international opinion for the treatment of displaced subcondylar fractures has become more aggressive after the rediscovery of the submandibular incision and the creation of new fixation material. We report 19 patients with displaced subcondylar fractures who were treated with reinforced rectangular plates. The pure titanium plates are slightly concave and measure 13 by 9 mm. We evaluated dental articulation, mouth opening, propulsion and duction and observed rapid recovery of mandibular kinetics and mandibular function. Use of this plate is a major progress in the treatment of fractures of the condyle.

CD44 isoforms with exon v6 and metastasis of primary N0M0 breast carcinomas

New isoforms of CD44 with alternatively spliced exons have recently been described. Expression of exon v6 seems to be of particular interest. It has indeed been associated with poorer outcome of breast cancer patients with node invasion at diagnosis. However, no data were available for patients N0M0 (with neither metastasis nor node invasion at diagnosis). Moreover, previous statistical analyses were realized using immunohistochemical methods to detect CD44v6 expression although several variants with exon v6 have been described. We investigated expression of isoforms containing CD44v6 using an RT-PCR approach and a panel of 25 normal breast specimens, 10 mammary fibroadenomas, 8 cystic samples and 52 primary breast tumors (38 invasive N0M0). Normal breasts, fibroadenomas, and cysts all express the same variant, A (with exon v6 only), while several transcripts are amplified in tumors. Expression of variants other than A correlates with acquisition of a malignant phenotype. Invasive cancers also express additional variants in comparison with in situ carcinomas. Metastasis capacities seem to be associated with transcription of variants other than A but also with no transcription of some of them, variants D (with exons v6 and v10) and L (with exons v6 to v10). Expression of variants D and L correlates with higher percentages of disease-free survival and better outcome. Expression of CD44 splice variants with exon v6, as detected by RT-PCR, might be a useful prognostic factor for breast cancer. However, since the series size is small, our results need to be confirmed by later studies on a larger number of patients.

Biodegradation and aquatic toxicity of beta-alaninediacetic acid (beta-ADA)

The aquatic toxicity and biodegradability of the new chelating agent beta-alaninediacetic acid (beta-ADA) were investigated. There is no inhibition effect of beta-ADA in the daphnia magna 24 h test up to a concentration of 1000 mg/L. The algal growth inhibition test resulted in an EC 50 of 19.7 mg/L. An EC 20 of 740 mg/L was determined in the luminescent bacteria test. An EC 50 was not obtained in this test up to a concentration of 2000 mg/L beta-ADA. The degree of biodegradation of beta-ADA was determined in a static and a continuous test. The beta-ADA removal reached 98% at the end of the test after eight weeks in the continuous test which was carried out with laboratory activated sludge units simulating a waste water treatment plant. Further, biodegradation and toxicity tests were coupled, i.e. the effluents of the laboratory activated sludge units were applied in the toxicity tests. A higher toxicity of the effluents of the test units in comparison with the control unit was not observed.

[The coral orbital floor. Its value in traumatology. The results of a multicenter study of 83 cases]

A madreporic coral graft was used for orbital floor reconstruction following facial trauma. This report presents a multicentric study of 83 patients with a follow-up period of 15 to 24 months. The results of this study indicate no significant rejection or infection opposed to so many synthetic implants outcome. The radiological follow-up demonstrates a partially resorption of the implant within about 2 years and its replacements by new bone. Coral implant was used to correct enophthalmos or diplopia due to enlarged orbital dimensions. It was technically easy to insert and its anatomic shape does not require to be fashioned before use. Its inflexibility allows to bridge large bone defects and this implant should be considered as an attractive alternative to autogenous grafts, avoiding a second surgical site, in reconstructing orbital floor fractures.

CD44 exon 6 expression as a possible early prognostic factor in primary node negative breast carcinoma

Breast cancer is the most common female malignancy affecting approximately one woman in eight. Many attempts have been made to define markers which may have potential clinical applications in diagnosis as well as therapy. New isoforms of CD44 with alternative spliced exons have recently been described. We studied the expression of CD44 exon 6 using a semi-quantitative RT-PCR reaction on a panel of 25 normal breast specimens, 10 mammary fibroadenomas, eight cystic samples and 52 primary breast tumors. Significant correlation was found between CD44 exon 6 expression and the overall survival of the N-M-population, P = 0.032, (logrank test by Mantel's method). The same result was also observed for the disease-free survival, P = 0.000002 (logrank test by Mantel's method). CD44 exon 6 expression, as detected by our RT-PCR-based method, might be a useful prognostic indicator of metastasis in breast cancer. However, these preliminary results need to be confirmed by later retrospective and prospective studies on a larger number of patients.

Cleavage of oligodeoxyribonucleotides from controlled-pore glass supports and their rapid deprotection by gaseous amines

A novel method for the deprotection of oligodeoxyribonucleotides has been developed. Gaseous amines such as ammonia or methylamine were employed under pressure to achieve mild and rapid deprotection conditions. For example, oligodeoxyribonucleotides having a (tert-butyl)phenoxyacetyl group for the protection of the exocyclic amino function of cytosine, adenine and guanine were released from controlled-pore glass supports and fully deprotected by ammonia or methylamine under gas phase conditions, at room temperature, within 35 or 2 min respectively.

Chiral phosphorothioates as probes of protein interactions with individual DNA phosphoryl oxygens: essential interactions of EcoRI endonuclease with the phosphate at pGAATTC

The contact between EcoRI endonuclease and the "primary clamp" phosphate of its recognition site pGAATTC is absolutely required for recognition of the canonical and all variant DNA sites. We have probed this contact using oligonucleotides containing single stereospecific (Rp)- or (Sp)- phosphorothioates (Ps). At the GAApTTC position, where the endonuclease interacts with only one phosphoryl oxygen at the central DNA kink, Rp-Ps inhibits and Sp-Ps stimulates binding and cleavage [Lesser et al. (1992) J. Biol. Chem. 267, 24810-24818]: in contrast, at the pGAATTC position both diastereomers inhibit binding. For single-strand substitution, the penalty in binding free energy (delta delta G0bind) is slightly greater for Sp-Ps (+ 0.9 kcal/mol) than for Rp-Ps (+ 0.7 kcal/mol). Binding penalties are approximately additive for double-strand substitution (Rp,Rp-Ps or Sp,Sp-Ps). Neither Ps diastereomer in one DNA strand affects the first-order rate constants for cleavage in the unmodified DNA strand, and only Sp-Ps inhibits the cleavage rate constant (3-fold) in the modified DNA strand. Thus, the second-order cleavage rate (including binding and catalysis) is inhibited 14-fold by Sp-Ps and 45-fold by Sp,Sp-Ps. In the canonical complex, the phosphate at pGAATTC is completely surrounded by protein and each nonbridging phosphoryl oxygen receives two hydrogen bonds from the endonuclease, such that in either orientation the increased bond length of P-S- inhibits binding. However, the pro-Sp oxygen interacts with residues that are connected (by proximity or inter-side-chain hydrogen bonding) to side chains with essential roles in catalysis, so cleavage is preferentially inhibited when these side chains are slightly displaced by the Sp-Ps diastereomer.

[Does the choice of mammoplasty pedicle influence the shape of reduced the reduced-sized breast?]

Thirty seven patients with breast hypertrophy were restrospectively reviewed with a mean follow-up of 2 years. Reduction mammoplasty was performed with 3 different pedicles (superior, inferior and both) involving a glandular resection of a least 500 g on each side in all cases. The results were evaluated according to both objective and subjective criteria. The choice of pedicle had a considerable influence on the results. The vertical limb usually increased with time (months), although its intraoperative length was 5 cm. The increasing length of the vertical limb varies according to the type of pedicle chosen. The mean length increase was 1.52 cm; 4.18 cm; 4.15 cm for superior, inferior, and both pedicles respectively. The different increase was statistically significant (p < 0.001) when the technic involving a superior pedicle was compared to a technic involving an inferior pedicle. No statistically significant difference was observed between technics using the inferior and both pedicles. A superior pedicle technic entails the lowest increase of the vertical limb length which in turns leads to better long-term cosmetic results.

Recurrent sclerosing Basal-cell carcinomas requiring ablative cranio facial surgery - a 3-case report

The authors report on 3 cases of facial recurrent sclerosing basal cell carcinomas requiring large ablative cranio facial surgery and reconstruction involving regional or even free flaps. Special emphasis is made on the aggressive behavior of this specific histological form and on the necessity of an early diagnosis, a radical initial treatment and a close life time follow-up. Surgery with careful histological control of the margins is the treatment of choice whereas radiotherapy is an alternative for small lesions or nonsurgical patients. This early and aggressive therapeutic management is essential in order to avoid recurrences often requiring disfiguring surgery.