Coronal Area Research Articles

Time variation analysis of the daily Forbush decrease indices

In the present paper we have analyzed the daily Forbush decrease indices from January 1, 1967 to December 31, 2003. First filtering the time series by Simple Exponential Smoothing, we have applied Scargle Method of Periodogram on the processed time series in order to search for its time variation. Study exhibits periodicities around 174, 245, 261, 321, 452, 510, 571, 584, 662, 703, 735, 741, 767, 774, 820, 970, 1062, 1082, 1489, 1715, 2317, 2577, 2768, 3241 and 10630 days with confidence levels higher than 90%. Some of these periods are significantly similar to the observed periodicities of other solar activities, like solar filament activity, solar electron flare occurrence, solar-flare rate, solar proton events, solar neutrino flux, solar irradiance, cosmic ray intensity and flare, spectrum of the sunspot, solar wind, southern coronal hole area and solar cycle, which may suggest that the Forbush decrease behaves similarly to these solar activities and these activities may have a common origin.

Expansion of the Alveolar Bone Crest with Ultrasonic Surgery Device: Clinical Study in Mandible

The purpose of this paper was to document the application to the split-crest mandibular procedure in two stage in order to avoid cortical resorption due to periosteal detachment in buccal cortical bone of the alveolar crest. Twenty-two healthy patients with non-contributory past medical history (14 women and 8 men, all non-smokers, mean age 59 years, range 54-65 years) were included in this study. After buccal mucoperiosteal flap was followed by a sagittal corticotomy in the coronal area of the alveolar crest and a second sagittal corticotomy, but in a lower (basal) position and two vertical corticotomies in the buccal wall, using a ultrasonic surgery device (Surgysonic, Esacrom, Imola Italy). Adequate crest expansion was achieved without compromising cortical vascularisation by utilising a combination of scalpel, thin chisels and threaded osteotomes (Bone System, Milano, Italy). Postoperative results were assessed by panoramic and periapical radiographs. Ossification of the osteotomy lines was evident and could be observed as sites with increasing radiopacity on panoramic and periapical radiographs 3 months after implants insertion. No dehiscence of the mucosa was observed. No patient suffered from hypoaesthesia. The mean horizontal bone increase in coronal area was 5±3 mm. Mandibular ridge expansion using a split-crest technique that included grafting the implant sites with a ultrasonic surgery device is a viable therapeutic alternative for implant placement in this patient population.

Rapid image stitching and computer‐aided detection for multipass automated breast ultrasound

Breast ultrasound (US) is recently becoming more and more popular for detecting breast lesions. However, screening results in hundreds of US images for each subject. This magnitude of images can lead to fatigue in radiologist, causing failure in the detection of lesions of a subtle nature. In this study, an image stitching technique is proposed for combining multipass images of the whole breast into a series of full-view images, and a fully automatic screening system that works off these images is also presented. Using the registration technique based on the simple sum of absolute block-mean difference (SBMD) measure, three-pass images were merged into full-view US images. An automatic screening system was then developed for detecting tumors from these full-view images. The preprocessing step was used to reduce the tumor detection time of the system and to improve image quality. The gray-level slicing method was then used to divide images into numerous regions. Finally, seven computerized features--darkness, uniformity, width-height ratio, area size, nonpersistence, coronal area size, and region continuity--were defined and used to determine whether or not each region was a part of a tumor. In the experiment, there was a total of 25 experimental cases with 26 lesions, and each case was composed of 252 images (three passes, 84 images/pass). The processing time of the proposed stitching procedure for each case was within 30 s with a Pentium IV 2.0 processor, and the detection sensitivity of the proposed CAD system was 92.3% with 1.76 false positives per case. The proposed automatic screening system can be applied to the whole breast images stitched together via SBMD-based registration in order to detect tumors.

Histological characteristics of newly formed cementum in surgically created one-wall intrabony defects in a canine model.

PurposePeriodontal regenerative therapies for defects created by severe periodontitis are mainly focused on bone regeneration. Although cementum regeneration needs to be better understood, it is believed to play an important role in periodontal regeneration. The first step toward a full understanding of cementum regeneration is to compare repaired cementum to pristine cementum. This study, which used histological techniques, was designed to focus on cementum regeneration and to compare pristine cementum to repaired cementum after surgical procedures with 8 and 24 week healing periods in a canine model.MethodsBuccal and lingual mucoperiosteal flaps of 10 beagle dogs were surgically reflected to create critical-sized defects. Intrabony one-wall defects, of which dimension is 4 mm width and 5 mm depth, were made at the distal aspect of mandibular second premolars and the mesial aspect of mandibular fourth premolars in the right and left jaw quadrants. Animals were sacrificed after 8 and 24 weeks post-surgery for histological specimen preparation and histometric analysis.ResultsThe repaired cementum was composed mostly of acellular cementum and cellular mixed fiber cementum and was thicker in the apical area than in the coronal area. The acellular cementum of the supracrestal area appeared to be amorphous. The newly formed cellular cementum was partially detached from the underlying circumpulpal dentin, which implied a weak attachment between new cementum and dentin, and this split was observed to a lesser extent in the 24 week group than in the 8 week group. The vertical height of the repaired cementum was greater in the 24 week group than in the 8 week group.ConclusionsWithin the limitations of this study, we can conclude that repaired cementum after root planing was mainly acellular cementum and cementum tissue that matured to a shape similar to pristine cementum as the healing progressed from 8 to 24 weeks.

Pearly penile papules regress in older patients and with circumcision

This study assesses the prevalence and correlates of pearly penile papules (PPP) in two non-genitourinary (GU) medicine male cohorts (<25 and >50 years). PPP were categorised in 188 university students (<25 years), based on self-examination, and 70 patients (>50 years), based on clinician examination. PPP were categorised from 1 to 4, based on increasing papule size and distribution. An anonymous questionnaire was used to identify associations with PPP prevalence. The prevalence of PPP was 38.3% in <25 years, and 11.4% in >50 years (P < 0.001). The prevalence of categories 3 and 4 PPP was 8.5% in <25 years, and 1.4% in >50 years (P < 0.05). In the younger age group, the prevalence of PPP was 26.5% in circumcised participants, and 42.4% in uncircumcised participants (P < 0.05), but was unrelated to either frequency of sexual intercourse or time since first sexual intercourse. In conclusion, PPP disappear with age, and any PPP in patients >50 years are less marked than those in patients <25 years. Patients should be advised accordingly. PPP are less prevalent in circumcised men. Patients could be advised to wear the foreskin rolled back - this may maximize exposure of the coronal area to normal abrasion, which may hasten PPP regression.

Clinical and Histological Comparison of Extraction Socket Healing Following the Use of Autologous Platelet-Rich Fibrin Matrix (PRFM) to Ridge Preservation Procedures Employing Demineralized Freeze Dried Bone Allograft Material and Membrane

Background:The healing potential of platelet growth factors has generated interest in using Platelet-Rich Plasma (PRP) in ridge preservation procedures. A canine study was performed to determine if extraction sites treated with platelet-rich fibrin matrix (PRFM) exhibit enhanced healing compared to sites treated with non-viable materials.Methods:Four dog’s extraction sockets were treated individually with PRFM, PRFM and membrane, Demineralized Freeze-Dried Bone Allograft (DFDBA) and membrane, PRFM and DFDBA, and untreated control. Treatment sequencing permitted clinical and histologic evaluation of healing at 10 days, 2, 3, 6 and 12 weeks.Results:Healing was more rapid in the PRFM and PRFM and membrane sites. By 3 weeks those sockets had osseous fill. Sites containing DFDBA had little new bone at 6 weeks. By 12 weeks those sockets had osseous fill but DFDBA particles were still noted in coronal areas.Conclusions:PRFM alone may be the best graft for ridge preservation procedures. Advantages: faster healing, and elimination of disadvantages involved in using barrier membranes.

Pseudotumor cerebri: Quantitative Normalwerte anatomischer Kennstrukturen im kraniellen MRT

Intracranial hypertension can change the morphology of anatomical structures that are critical in the evaluation of pseudotumor syndromes. The purpose of our study was to establish the normal range of such markers of intracranial hypertension and to consider a dependency on sex, age and body-mass index (BMI). 123 persons without signs or symptoms of intracranial hypertension (63 females, 60 males, 18- 86-years-old, mean 49.5 SD17.8 years, mean BMI 25.3 SD42) were prospectively enrolled and MRI was performed at 3T. A STIR sequence in the coronal plane was used to measure the width of the optic nerve, the perioptic fluid rim and the total optic nerve sheath diameter in 4 different locations behind the eyeball. The height and width of the pituitary and Meckel's cave were also measured and the area was calculated. The mean width of the optic nerve sheath narrows significantly from anterior (mean 5.3 SD 0.6 mm) to posterior (mean 4.1 SD 0.4 mm), as does the perioptic fluid rim (mean 1.4 SD 0.3 mm vs. mean 1.0 SD 0.2 mm) and--to a lesser extent--the optic nerve itself (mean 2.4 SD 0.4 mm vs. mean 2 SD 0.3 mm, p=0.000 for all). There was no statistically relevant correlation of the width of the optic nerve sheath with age. The coronal area of Meckel's cave was independent of sex, age or BMI (mean 39 SD 9.3 mm2). The height of the pituitary differed little in women (mean 4.4 SD 0.9 mm) and men (mean 4.2 SD 0.8 mm), but we found a significant negative correlation with age in women only (r = -0.38, p = 0.01). The presented typical values and their deviations serve as a basis for the evaluation of pathologies in patients suspected of having pseudotumor syndrome.

Coronal and apical leakage analysis of two different root canal obturation systems

This study compared the coronal and apical leakage of AH Plus with gutta-percha to that of Epiphany with Resilon. Twenty-four single rooted teeth were instrumented and divided into 2 groups according to the solutions for smear layer removal and the obturation materials employed: Group A - 17% EDTA-T and AH Plus with gutta-percha; Group B - primer and Epiphany with Resilon. The Group B specimens were light-cured in the coronal area for 20 s. The external root surfaces were covered with a double layer of ethyl cyanoacrylate, except for the apical foramen and the cavity access. The teeth were immersed in 0.5% methylene blue for 48 h. The specimens were rinsed, dried and axially split for dye penetration measurement with the ImageLab 2.3 software. The t-test showed no significant differences for coronal leakage between the groups, but there were significant differences for apical leakage between the groups (P < 0.05). AH Plus with gutta-percha and Epiphany with Resilon provided the same coronal seal, whereas Epiphany with Resilon provided the best apical seal.

Extraction of Impacted Maxillary Canines With Simultaneous Implant Placement

When impacted maxillary canines are not amenable to orthodontic traction or reimplantation, extraction is the only option available, followed by implant placement. If apical and ridge crest bone remains after the extraction of the maxillary canines, an immediate implant can be placed. The implant is anchored bicortically with good primary fixation. This article presents a new surgical technique that allows an immediate implant placement after the extraction of the maxillary canines. The full circumference of the implant is left without bone coverage, except for the apical and coronal area.

A novel murine model for the study of human renal cryoablation

to develop a reproducible, non-debilitating in vivo murine model of human renal cryoablation using a standard closed argon-delivery system. Custom engineered 2-mm conical tip cryoprobes for use on the standard argon-based cryoablation unit (Endocare, Inc. Irvine, CA, USA) were used to create small controllable iceballs (−160 °C) in the mouse kidney. The time to create a 4-mm cryolesion was compared using a contact vs puncture technique in 10 mice. To show consistency of the induced-freeze injury, a 4-mm iceball was created in 20 murine renal units and the time to creation and the size of the resultant cryolesion measured. To investigate lesion regression and histological changes, we created a 4-mm renal cryolesion in 28 mice and killed four each at 1, 3, 7, 14, 21, 28, and 35 days. The measured coronal cross-sectional area of the cryoablation site at necroscopy was compared to the initial calculated area as a percentage. To assess renal preservation, blood urea nitrogen (BUN) and creatinine levels at 1 week after cryoablation or sham ablation was compared (10 mononephric mice in each group). The time to create the desired iceball was 1.9 times quicker using the puncture vs the contact technique. The mean (sd) time to forming a 4-mm iceball was 35.3 (4.8) s with a mean maximum length of the resultant post-thaw injury of 5.7 (0.5) mm and a 9% coefficient of variance. Regression analysis of the two-dimensional cross-sectional coronal area of the cryolesion showed a statistically significant linear pattern of regression over time (P = 0.037) and classic histological findings. There was no significant difference in the BUN or creatinine levels in mononephric mice 1 week after cryotherapy compared with the sham-ablated controls. We describe a reproducible, non-debilitating, easily manipulated murine model for the study of human renal cryoablation.

Twenty-Seven-Day Variation of Galactic Cosmic Rays

Neutron monitor data observed at Climax (CL) and Huancayo/Haleakala (HU/HAL) have been used to calculate the amplitude A of the 27-day variation of galactic cosmic rays (CRs). The median primary rigidity of response, Rm, for these detectors encompasses the range 18 ≤Rm≤46 GV and the threshold rigidity R0 covers the range 2.97≤R0≤12.9 GV. The daily average values of CR counts have been harmonically analyzed for each Bartels solar rotation (SR) during the period 1953 – 2001. The amplitude of the 27-day CR variation is cross-correlated to solar activity as measured by the sunspot number R, the interplanetary magnetic field (IMF) strength B, the z-component Bz of the IMF vector, and the tilt angle ψ of the heliospheric current sheet (HCS). It is anticorrelated to the solar coronal hole area (CHA) index as well as to the solar wind speed V. The wind speed V leads the amplitude by 24 SRs. The amplitude of the 27-day CR variation is better correlated to each of the these parameters during positive solar polarity (A>0) than during negative solar polarity (A 0 from that during A 0 (1971 – 1980) from that during A2>0 (1992 – 2001) owing to solar wind speed.

Regional differences of expression of bone morphogenetic protein‐2 and RANKL in the rat dental follicle

Tooth eruption requires alveolar bone resorption and bone formation. The coronal half of the dental follicle probably mediates the bone resorption seen in the coronal region of the alveolar bony crypt, and the basal half of the follicle mediates bone growth in the basal region. We hypothesized that the expression of a gene for bone resorption--receptor activator of nuclear factor kappa B ligand (RANKL)--would be higher in the coronal than in the basal region of the follicle. Conversely, the level of expression of bone morphogenetic protein-2 (BMP-2), a gene for bone formation, would be higher in the basal region. Results obtained using laser-capture microdissection and real-time reverse transcription-polymerase chain reaction (RT-PCR) confirmed the hypothesis. Scanning electron micrographs of the bony crypt showed that the coronal area of the crypt was scalloped in appearance (bone resorption), whereas the basal area was trabecular (bone formation). Thus, the differences in bone activity at opposite poles of the crypt appear to be caused by differences in the regional expression of genes in the dental follicle and suggest a molecular mechanism whereby the dental follicle could regulate both the alveolar bone resorption and formation needed for eruption.

Ultraviolet, hard X-ray, and gamma-ray emission of solar flares recorded by VUSS-L and SONG instruments in 2001–2003

The results of simultaneous measurements of variations of UV radiation (in a band near the hydrogen Lα line, 121.6 nm) and hard X-ray and gamma-ray radiation (50 keV-200 MeV) performed by the VUSS-L and SONG instruments, respectively, onboard the CORONAS-F spacecraft are presented for periods of solar flares. Variations in the Lα ultraviolet radiation during the impulsive phase of a flare are shown to be synchronous with those of hard X-ray radiation. Temporal variations of UV and X-ray fluxes correspond to the progressive heating of higher and higher regions of the solar atmosphere and the energy transfer from the lower layers of the solar atmosphere to the coronal areas of flare regions. The energy of electrons in beams arising during the impulsive phase of flares can be as high as 500 keV. The velocity of the energy propagation from the regions of its release to the upper layers of the solar atmosphere can reach several tens of kilometers per second.

Morphological and proliferative analysis of the healing tissue in human alveolar sockets covered or not by an e-PTFE Membrane: A preliminary immunohistochemical and ultrastructural study

Healing tissues of extraction sockets have been used, as autografts, for the treatment of periodontal bony defects. These tissues have proved to be more effective in inducing bone formation than mature bone. However, there are limited data regarding the nature and proliferative activity of its cells. The aim of this pilot study was to analyze the nature and the proliferative activity of cells present in newly formed tissue from human extraction sockets, covered or not by an e-PTFE membrane. The healing tissue of 6 pairs from human alveolar sockets covered or not by an e-PTFE membrane, collected 4 weeks after tooth extraction was analyzed. The specimens were observed using light and transmission electron microscopy (TEM). The immunohistochemical characterization of the tissues included type I collagen, osteonectin and bone sialoprotein detection. The proliferation rates of the tissues were obtained using PCNA labeling. Cells and extracellular matrix were labeled for type I collagen, osteonectin and bone sialoprotein, in both groups. PCNA antibodies revealed significant higher proliferation rates in the coronal areas than in the apical areas of the tissues, independent of which group they belonged to. TEM showed cells containing a Golgi apparatus, rough endoplasmic reticulum and mitochondria indicative of secretory cells, in both groups. In the apical area of the test and control groups, the extracellular matrix exhibited more bundles of collagen fibrils than in the coronal area. The cells of healing tissue of dental sockets are osteoblastic in nature. Additionally, they present higher proliferating rates in the coronal areas, independent of the use of the e-PTFE membrane.

Controlled Trial of Pamidronate in Children With Types III and IV Osteogenesis Imperfecta Confirms Vertebral Gains but Not Short-Term Functional Improvement

Bisphosphonates have been widely administered to children with OI based on observational trials. A randomized controlled trial of q3m intravenous pamidronate in children with types III and IV OI yielded positive vertebral changes in DXA and geometry after 1 year of treatment, but no further significant improvement during extended treatment. The treated group did not experience significantly decreased pain or long bone fractures or have increased motor function or muscle strength. Bisphosphonates, antiresorptive drugs for osteoporosis, are widely administered to children with osteogenesis imperfecta (OI). Uncontrolled pamidronate trials in OI reported increased BMD, vertebral coronal area, and mobility, and decreased pain. We conducted a randomized controlled trial of pamidronate in children with types III and IV OI. This randomized trial included 18 children (4-13 years of age) with types III and IV OI. The first study year was controlled; 9 children received pamidronate (10 mg/m2/day IV for 3 days every 3 months). Four children in each group also received recombinant growth hormone (rGH) injections (0.06 mg/kg/day for 6 days/week). Seven children in the treatment group received pamidronate for an additional 6-21 months. All patients had L1-L4 DXA, spine QCT, spine radiographs, and musculoskeletal and functional testing. In the controlled phase, treated patients experienced a significant increase in L1-L4 DXA z score (p < 0.001) and increased L1-L4 mid-vertebral height (p = 0.014) and total vertebral area (p = 0.003) compared with controls. During extended treatment, DXA z scores and vertebral heights and areas did not increase significantly beyond the 12-month values. Fracture rate decreased significantly in the upper extremities (p = 0.04) but not the lower extremities (p = 0.09) during the first year of treatment. Gross motor function, muscle strength, and pain did not change significantly during the controlled or extended treatment phases. A controlled trial confirmed the spine benefits of short-term pamidronate treatment in children with types III and IV OI. Pamidronate increased L1-L4 vertebral DXA and decreased vertebral compressions and upper extremity fractures. Vertebral measures did not improve during the extended treatment phase. The treatment group did not experience decreased lower extremity long bone fractures, significant improvement in growth, ambulation, muscle strength, or pain. There was substantial variability in individual response to treatment.

CORONAL IMAGING TO ASSESS URINARY TRACT STONE SIZE

Urinary tract stones are typically measured using axial images from computerized tomography (CT). Such images provide a precise measurement of stone length and width. However, cephalocaudad dimensions can be difficult to determine from axial images. Coronal reconstructions, which can more accurately measure cephalocaudad dimensions, are seldom used to measure stones. We determined if coronal reconstructions could aid in more precisely determining stone size. CT in patients who had undergone CT to evaluate urolithiasis at our institution during the 9-month period of January 2001 to September 2001 were reviewed. Length and width were measured using axial images, and cephalocaudad length and width were measured using coronal reconstructions. Cephalocaudad length was also estimated from axial images. Total area was calculated from axial and coronal reconstructions. The paired t test was used to assess statistical significance. The CT images of 102 patients with a total of 151 stones had undergone coronal reconstructions and, thus, were included in the study. Mean area in the axial and coronal reconstruction groups was 22.23 and 31.29 mm, respectively. Mean greatest axial dimension (length or width) was 4.87 mm and mean greatest coronal dimension (cephalocaudad length) was 6.51 mm. Cephalocaudad length estimated from axial images was 8.8 mm. Differences for all 3 of these comparisons (axial vs coronal area, greatest axial vs coronal dimension and estimated vs actual cephalocaudad length) proved to be statistically significant (p <0.0001). While urinary tract stones have typically been measured using axial images, coronal images provide a different impression of stone size. These data demonstrate that examining only axial images provides an inaccurate measure of stone size. We suggest that coronal images should also be used to measure more accurately stone size, which is critical for clinical decision making.

Medical grade calcium sulfate hemihydrate in healing of human extraction sockets: clinical and histological observations at 3 months.

Following tooth extraction, remodeling and resorption of the alveolar bone at the extraction site characterize wound healing. This produces a reduction in ridge volume and difficulties in delayed placement of implants in an ideal position. Medical grade calcium sulfate hemihydrate (MGCSH) has been proposed as a graft material in extraction sockets to minimize the reduction in ridge volume. The aim of the present study was to investigate the influence of MGCSH on the histopathologic pattern of intrasocket regenerated bone and to evaluate histologically the healed MGCSH grafted extraction socket site 3 months postextraction MGCSH was grafted in 10 fresh human extraction sockets in 10 patients. Five post-extraction sockets were used as controls. At 3 months a cylindrical tissue specimen, 2.5 mm in diameter, was trephined from the previously grafted site followed by implant placement. Non-decalcified specimens were sectioned at a cross-horizontal plane and stained with fast green, toluidine blue, and Van Kossa stains for histological and histomorphometrical examination. Histologically, MGCSH was not observed in most of the specimens. Newly formed bone with lamellar arrangements was identified in all the horizontal sections with no difference between apical, medium, and coronal areas. The mean trabecular area in the coronal sections was 58.6% +/- 9.2%; in the medium sections, 58.1% +/- 6.2%; and in the apical sections, 58.3% +/- 7.8%. The differences were not statistically significant. MGCSH seems to be an ideal graft material in extraction socket bone regeneration because it is almost completely resorbable, and it allows a new trabecular bone arrangement at 3 months.

MRI and in situ hybridization reveal early disturbances in brain size and gene expression in the megencephalic (mceph/mceph) mouse.

The mouse model for megencephaly, mceph/mceph, carries a truncating deletion in the Shaker-related voltage gated potassium channel gene 1. Affected mice display neurological disturbances and motor dysfunctions. Symptoms begin to show at 3-4 weeks of age. The cause of the brain enlargement is not clear. To elucidate early events in the development of the disease we used magnetic resonance imaging (MRI) to quantify, over time, the increase in size of several discrete brain regions in the same mice at 3, 8 and 12 weeks of age. We also analysed markers for neuropeptides and growth factors to explore their possible involvement at an early stage. The results show an enlargement of the total coronal area of the brain already at 3 weeks of age. Total brain volume, ventral cortex, hippocampal formation and cerebral cortex were enlarged at 8 weeks and onwards. Thalamus, brainstem, cerebellum and spinal cord did not differ from controls even at 12 weeks. We also report distinct disturbances in the expression of brain-derived neurotrophic factor, insulin-like growth factor binding protein 6 and several neuropeptides at 2 and 3 weeks of age, that is, before an obvious behavioural phenotype can be observed. These results provide an objective description of the size changes in different brain regions of the mceph/mceph mouse, and suggest that certain molecules could be involved in the early processes underlying these changes.

Enhancement of osseointegration of implants placed into extraction sockets of healthy and periodontally diseased teeth by using graft material, an ePTFE membrane, or a combination.

Advanced periodontal disease as well as failed endodontic teeth are the most common reasons for tooth removal and simultaneous implant placement. To determine whether the addition of a bone substitute graft material and/or a guided bone regeneration membrane added to the site of an immediately placed implant would increase the development of lamellated bone, particularly in the presence of bone defects. Four treatment modalities associated with the immediate placement of hydroxyapatite-coated endosteal screw implants into extraction sockets of healthy (C/H) and periodontally diseased teeth (T/PD) were tested. Five dogs with healthy teeth and five dogs with naturally occurring periodontitis were chosen for the study. Each dog received eight implants after extraction of four mandibular and four maxillary premolars. Four implants were submerged for 3 months and four for 6 months. The implants were either inserted alone (subgroup A); surrounded by a GORE-TEX membrane (subgroup B; W.L. Gore & Associates Inc., Flagstaff, AZ, USA); surrounded by PepGen P-15 (Dentsply Friadent CeraMed Dental Co. Denver, CO, USA) at coronal area (subgroup C); or surrounded by a combination of graft material and the ePTFE membrane (subgroup D). Implants in group A were osseointegrated in both C/H and T/PD groups with similar bone-implant contact ratios (BICRs). ePTFE membrane significantly improved the BICR of the 6-months implants, whereas graft material significantly increased the BICR at 3 months and maintained the gain thereafter. The graft material and membrane combination further improved the BICR and significantly increased lamellated bone in crestal bone of all implants. This study provides experimental evidence in support of use of graft material with immediately placed implants, particularly in presence of bone defects that initially reduce the BICR such as in periodontitis. Adding an ePTFE membrane to graft material resulted in a greater replacement of woven bone by lamellated bone. Clinical trials in humans are recommended as a follow-up of this experimental study.

Neonatal cerebral hypoxia–ischemia causes lateralized memory impairments in the adult rat

Neonatal hypoxia-ischemia (HI) has been extensively studied in a rat model characterized by unilateral brain damage (Rice-Vannucci Model). However, as well as in humans, each rat brain hemisphere is distinctly involved in cognitive functions, as for example retrieval of emotionally based memory, and neurochemical asymmetries have been described. In this paper we investigated whether hypoxia-ischemia could cause distinct cognitive deficits depending on which hemisphere is damaged. Seven-day-old male Wistar rats were submitted to permanent occlusion of left or right common carotid artery and were exposed to a mixture of 8% oxygen-92% nitrogen for 2.5 h. On adulthood, these rats were trained in step-down inhibitory avoidance and in two tasks in the Morris water maze. Both experimental groups (right and left lesioned) showed a deficit of retrieval in the inhibitory avoidance task compared to controls, although rats with right hemisphere lesion showed a significantly greater deficit than the left damaged group (P<0.05). In the Morris maze, both damaged groups presented cognitive deficits in the reference memory task (P<0.05), however only the right damaged group had an impairment in the working memory task. Brain coronal areas, at levels +1.20 and -3.30 mm from bregma of both HI groups were smaller than those of control, with no differences between the right and left damaged groups (P<0.05). These results show that cerebral hypoxia-ischemia in neonatal rats causes asymmetric behavioral outcomes depending on which of the hemispheres is lesioned and support the hypothesis of lateralization of cognitive functions in the rodent brain.