Augmented Volumes Research Articles

Effect of Therapeutic Radiation on Polycaprolactone/Hydroxyapatite Biomaterials in a Calvarial Model.

Bone defects caused by cancer resection often require postoperative radiotherapy. Although various synthetic polymers have been introduced as graft materials, their biological behavior after radiation exposure remains unclear. Here, we investigated how polycaprolactone/hydroxyapatite (PCL/HA) implants respond to therapeutic radiation exposure (in terms of volume and bone regeneration). Four 8mm diameter calvaria defects were surgically created on the parietal bone of 6 rabbits. PCL/HA implants made of porous, solid, and hybrid polymers were grafted by random placement in each defect. The fourth defect was left untreated. Four weeks after surgery, radiation exposure was conducted weekly for 6 weeks (total: 48Gy). Micro-computed tomography and histologic analysis were performed at 3 and 6 months, and 6 months postradiation, respectively. The total augmented volumes of all implants showed no significant differences between 3- and 6-months postradiation computed tomography images. In histologic analysis, new bone areas were 0.45±0.11mm2, 2.02±0.34mm2, and 3.60±0.77mm2 in solid, hybrid, and porous polymer grafts, respectively. Bone regeneration was limited to the periphery of the defect in the hybrid and porous polymer grafts, whereas new bone formed inside the porous implant. The total augmented volume of the defect was maintained without significant absorption even after radiation exposure. The PCL/HA implant maintained its structure despite radiation exposure. The porous PCL/HA implant demonstrated excellent bone regeneration, followed by the hybrid and solid implants. The PCL/HA implant is a promising candidate for bone defect reconstruction.

Composed for Solo Guitar or String Orchestra? The Fluid Incarnations and Pedagogical Opportunities of Wallace Stevens’s The Man with the Blue Guitar

This article elaborates the critical, editorial, and pedagogical challenges and opportunities raised by Wallace Stevens’s The Man with the Blue Guitar (both the book and the title poem). It ranges from a consideration of the title poem’s unpublished autograph and the preliminary appearance of a selection of cantos in Twentieth Century Verse and Poetry to the book published by Knopf in 1937, its subsequent repackaging in 1952, and the different ways in which especially the title poem has been integrated in selected, collected, and artistically augmented volumes for the English-speaking market, as well as in translation. Thus, a text-genetic narrative and publication history of continuous material transformations emerges that squares well with the aesthetics propagated and enacted by Stevens’s open series of variations on a theme.

CCR2 of Tumor Microenvironmental Cells Is a Relevant Modulator of Glioma Biology.

Glioblastoma multiforme (GBM) shows a high influx of tumor-associated macrophages (TAMs). The CCR2/CCL2 pathway is considered a relevant signal for the recruitment of TAMs and has been suggested as a therapeutic target in malignant gliomas. We found that TAMs of human GBM specimens and of a syngeneic glioma model express CCR2 to varying extents. Using a Ccr2-deficient strain for glioma inoculation revealed a 30% reduction of TAMs intratumorally. This diminished immune cell infiltration occurred with augmented tumor volumes likely based on increased cell proliferation. Remaining TAMs in Ccr2-/- mice showed comparable surface marker expression patterns in comparison to wildtype mice, but expression levels of inflammatory transcription factors (Stat3, Irf7, Cox2) and cytokines (Ifnβ, Il1β, Il12α) were considerably affected. Furthermore, we demonstrated an impact on blood vessel integrity, while vascularization of tumors appeared similar between mouse strains. The higher stability and attenuated leakiness of the tumor vasculature imply improved sustenance of glioma tissue in Ccr2-/- mice. Additionally, despite TAMs residing in the perivascular niche in Ccr2-/- mice, their pro-angiogenic activity was reduced by the downregulation of Vegf. In conclusion, lacking CCR2 solely on tumor microenvironmental cells leads to enhanced tumor progression, whereby high numbers of TAMs infiltrate gliomas independently of the CCR2/CCL2 signal.

Breast Augmentation by Fat Transplantation With Adipose-Derived Stem/Stromal Cells.

BackgroundSurgical methods using implants were broadly selected for breast augmentation surgery until recently; however, owing to several associated problems, fat transplantation using adipose-derived stem/stromal cells (ADSCs) has been suggested as an alternative.ObjectivesThis study evaluated the clinical benefits of fat transplantation using ADSCs for breast augmentation.MethodsThe clinical effects were investigated in 105 patients who underwent breast augmentation with ADSCs and fat transplantation. Liposuction was performed in the abdominal and/or thigh regions; ADSCs were isolated from the fat, mixed with refined fat, and transplanted into each breast; and changes in the breast volume were measured.ResultsThe average increase in breast volume was approximately 185 mL at 2 weeks after operation. Fat engraftment rates were 85.1, 75.1, and 73.7% of augmented volumes after 1, 3, and 6 months, respectively. A total of 39 patients who received >60 million ADSCs exhibited a transplanted fat engraftment rate of 90.5% (average increase, 162 mL), whereas this rate was 68.9% (average increase, 115 mL) in 31 patients who received <60 million ADSCs.ConclusionsThis study demonstrates that breast augmentation with ADSCs and fat transplantation is effective. Surgical outcomes substantially improved with increased numbers of implanted ADSCs.Level of Evidence: 4

Lateral onlay grafting using different combinations of soft-type synthetic block grafts and resorbable collagen membranes: An experimental in vivo study.

To observe the sequential healing of lateral onlay grafts in terms of volumetric and histological changes when using different combinations of synthetic soft-type block bone and resorbable collagen membranes. A lateral onlay graft procedure was applied at the chronic narrow alveolar ridge of the mandible in 15 beagle dogs. The groups were allocated as follows: (a) empty control; (b) onlay graft using soft-type block bone 1 (hydroxyapatite [HA]: β-tricalcium phosphate [β-TCP]=15:85) and a non-cross-linked collagen membrane (MP-BG group); (c) onlay graft using soft-type block bone 2 (HA:β-TCP=60:40) and a non-cross-linked collagen membrane (OC-BG group); and (d) onlay graft using soft-type block bone 1 (HA:β-TCP=15:85) and a cross-linked collagen membrane (MP-CM group). Volumetric and histomorphometric analyses were performed at 4, 8 and 16weeks postoperatively. No clinical complications occurred in any of the groups. The OC-BG group showed significantly larger total augmented volumes than the control and MP-BG groups after 8 and 16weeks. The areas of new bone were significantly larger in the OC-BG group than the other groups at 16weeks. The horizontal thickness of the augmented ridge was significantly larger in the OC-BG group than in the control group at 16weeks. The OC-BG group showed superior volume maintenance and osteogenic potential for up to 16weeks compared to the other groups in an onlay graft model of the dog mandible despite the displacement of the bone graft.

Sinus floor elevation in sites with a perforated schneiderian membrane: What is the effect of placing a collagen membrane in a rabbit model?

To investigate the healing following sinus grafting in sites with a perforated schneiderian membrane repaired using a collagen membrane, compared to control sites without membrane perforation. Following elevation of the sinus membrane in 16 rabbits, each sinus was assigned to one of the following groups: (a) intentional schneiderian membrane perforation, followed by the placement of a collagen membrane and bone grafting (group SMP) and (b) bone grafting without a perforation of the schneiderian membrane and without a collagen membrane placement (control group). At 2 and 4weeks (n=8 for each time-point), microcomputed tomographic (micro-CT) and histomorphometric analyses were performed. Overall new bone formation in group SMP was significantly delayed compared to the control group at 2 and 4weeks (1.58±1.25% vs. 9.23±2.69% at 2weeks, 10.43±3.55 vs. 17.86±4.11% at 4weeks, p<0.05). At 2weeks, new bone formation for the areas close to lateral (1.19±2.02%) and medial sinus bone walls (3.17±1.98%) was markedly delayed in group SMP compared to the control group (13.08±6.13% and 12.75±5.63%, respectively, p<0.05), but there was no statistical difference in those areas at 4weeks (p>0.05). The augmented volumes at 2 and 4weeks were not statistically significantly different in both groups. The perforation of the schneiderian membrane and the repair using a collagen membrane delayed new bone formation in the augmented sinuses. However, the extension of the collagen membrane on the sinus bone walls was also attributable to this delayed bone formation.

Influence of the position of the antrostomy in sinus floor elevation assessed with cone-beam computed tomography: Arandomized clinical trial.

The aim of the present study was to evaluate dimensional variations of augmented sinus volumes after sinus floor elevation using a lateral approach placing the antrostomy close to the sinus floor or more cranially to it. Twenty-four healthy volunteers in need of sinus floor elevation were included in the study. The lateral approach was adopted placing the antrostomy randomly either close to the level of the sinus floor (group A) or approximately 3-4mm cranially (group B). Cone-beam computed tomography (CBCT) was done before surgery (T0) and after 1week (T1) and 9months (T2), and analyses on dimensional variations were performed. CBCT of 10 patients per group were analyzed. At T1, the sinus floor was found to be elevated by 9.8±2.1mm in group A and 10.9±1.9mm in group B. At T2, shrinkage of 2.0±1.7mm in group A and 1.4±2.5mm in group B was observed. The area was reduced approximately 18-24% between T1 and T2. The sinus mucosa width increased by 4.3-5mm between T0 and T1, and regained the original dimensions at T2. The more cranial the antrostomy, the greater the augmentation height after 9months.

Bone Regeneration of Peri-Implant Defects Using a Collagen Membrane as a Carrier for Recombinant Human Bone Morphogenetic Protein-2.

This study is designed to determine the effect of collagen membrane (CM) soaked with bone morphogenetic protein-2 (rhBMP-2) for the treatment of peri-implant dehiscence defects. Material and Methods. Three treatment groups were allocated at each defect in 5 dogs: (i) collagenated synthetic bone (OC) and CM soaked with rhBMP-2 (BMP group), (ii) OC and CM soaked with saline (nonBMP group), and (iii) no further treatment (control group). Titanium pins were used to stabilize the membranes in two dogs. Radiographic and histomorphometric analyses were performed 4 weeks later. Results. The median augmented volumes were 4.27 mm3, 6.24 mm3, and 2.75 mm3 in the BMP, nonBMP, and control groups, respectively; the corresponding median first bone-to-implant contact (fBIC) distances were 3.25 mm, 3.08 mm, and 2.56 mm (P > 0.05). The placement of pins (with the BMP and nonBMP groups pooled) significantly improved bone regeneration: the augmented volumes were 17.60 mm3 with pins and 3.68 mm3 without pins (P = 0.024), with corresponding fBIC distances of 2.25 mm and 3.31 mm, respectively (P < 0.001). Conclusions. The addition of rhBMP-2 to CM failed to improve bone regeneration of peri-implant dehiscence defects compared to using an unsoaked CM after 4 weeks. However, the stabilization of CMs using pins positively influenced the outcomes.

DAMS IN TIME OF WATER NATIONALISM

A dam, in most cases is a large, impressive concrete structure. A commanding number of large dams exist with over 45000 estimated in the world. It is important to understand such a concrete structure not only from a technical perspective, but also from the view of local community in the region of the dam. Also, it is important to know the international impact of a dam on a river basin and the measures necessary for implementing a dam, as well as the positive and negative effects of dam construction itself. Preliminary measures aim to characterize a river regarding natural, geological, geographical patterns, human geographical distribution, and food production. Prospective trends, such as the need for augmented water volumes for a water-fed agriculture, industrialization, energy, and river transportation, can influence decisions connected to dam building. Recently, climate change, a phenomenon considered as human-induced, at least partially, and the prospect of a water-stressed world, are another elements that affect decisions about build dams, especially regarding water security and green energy and a renewable resource under threat. This paper presents the main administrative requirements for a team involved in dam construction, including their specific tasks and interactions. The main aim of this paper is to establish political meaning of dams, and their capacity to influence economics, society, and the environment in an interconnected world.

Abstract 396: GRK5-mediated Exacerbation of Ischemic Heart Failure Involves Cardiac Immune-Inflammatory Responses

Rationale: Coronary artery disease and subsequent myocardial ischemia (MI) are the most common cause of heart failure (HF) in the US. G protein-coupled receptor (GPCR) kinase 5 (GRK5) has been shown to be upregulated in failing human myocardium. While the canonical role of GRKs is to desensitize receptors via phosphorylation, it has been shown that GRK5 can also locate to the nucleus of cardiomyocytes where it can exert GPCR-independent effects that promote maladaptive cardiac hypertrophy after hypertrophic stress. Despite numerous data indicating the importance of GRK5 in hypertrophy, it is still unknown if GRK5 has a role in ischemic heart disease. Objective: In this study, we investigated the critical role that GRK5 plays after myocardial ischemic injury with a novel aspect being the regulation of immune and inflammatory responses including recruitment of immune cells to the injured heart. Methods and Results: Cardiac-specific GRK5 transgenic mice (Tg-GRK5) and non-transgenic littermate (NLC) control mice were subjected to MI. Tg-GRK5-HF mice showed decreased cardiac function (both global and segmental contractility) as well as augmented left ventricular diameters and volumes compared to NLC-HF mice. Heart weight (HW) to body weight or tibia length ratios as well as mRNA expression of all major adverse remodeling-associated biomarkers (ANF, BNP, b-MHC) were increased in the TgGRK5-HF compared to NLC-HF. Cardiac fibrosis in the border zone (BZ) area as well as mRNA levels of Collagen-1 (Col-1), Col-3, MMP2 and CTGF were higher in TgGRK5-HF compared to NLC-HF, strongly suggesting increased adverse remodeling. Inflammatory Cytokines (IL-6 and IL-1beta) were augmented in TgGRK5-HF compared to NLC-HF and contribute at least in part to increased immune cell recruitment in the heart. In fact, we found both Neutrophils and T-lymphocytes (T- cells) augmented in the BZ and infarct zone. Conclusions: Our study shows that cardiac GRK5 has a detrimental effect during ischemic HF. GRK5 overexpression causes reduced cardiac function and increased immune cell recruitment/inflammation. Further, these results suggest GRK5 as a potential therapeutic target to limit HF development after ischemic injury.

Sinus augmentation using BMP‐2 in a bovine hydroxyapatite/collagen carrier in dogs

The objective of this study was to determine the efficacy of bone morphogenetic protein 2 (BMP-2) in a bovine hydroxyapatite/collagen (BHC) carrier to augment bone formation in a canine nasal sinus model. Eight mongrel dogs, approximately 12 months old and 30 kg in weight were used. Following preparation of bilateral sinus access windows, BHC alone (control) or loaded with E. coli-derived BMP-2 at 0.1 mg/ml was implanted in four animals, and BHC loaded with E. coli-derived BMP-2 at 0.5 and 1.5 mg/ml was implanted in four animals. The animals were euthanized at 20 weeks when block sections were obtained for micro-computed tomography and histometric analyses. Total augmented volumes did not differ significantly between groups. Histometric analysis showed significantly enhanced bone formation for the BMP-2 groups compared with control. BMP-2 in a BHC carrier, even at the low 0.1-mg/ml concentration, induces osteogenic activity, enhancing local bone formation in a canine sinus model.

Evaluation of bone volume changes after sinus floor augmentation with autogenous bone grafts

The aim of this study was to establish an objective method for quantitative evaluation of bone volume change after sinus augmentation. 11 sinuses in 9 patients were evaluated by computed tomography images taken before treatment (T0), and 3 months (T1) and at least 1 year (T2) after sinus augmentation. Based on the 3D digital subtraction technique, augmented bone images were extracted and bone volumes were calculated from voxel numbers of the extracted images. The mean augmented bone volumes at T1 and T2 were 2.46cm3 and 1.85cm3, respectively. These bone volume changes were statistically significant and the mean bone volume change±SE was −24.8%±6.1%. Loss of augmented bone was observed in all except one of the patients. The correlation coefficient between bone volume change and elapsed time was −0.64, which was statistically significant and indicated that bone resorption progressed with elapse of time after sinus augmentation. The authors’ method of analysis enabled visualization of augmented bone and objective assessment of bone volume change. Within the limited number of cases, the present investigation demonstrated a significant decrease in augmented bone volume between 3 and 23 months after surgery.

Contribution of Breast Density to the Volume of the Augmented Breast: A Preliminary Study

Prediction of soft tissue contribution to the shape, volume and texture of the augmented breast proves to be an ever-challenging, uncontrollable variable. Similarly, the understanding of the contribution of breast density in breast augmentation has been elusive and, generally, not well studied. With the aid of three-dimensional photographic analysis, the present preliminary study examined the contribution of differing breast densities to the overall volume of the augmented breast. All patients undergoing primary augmentation over a six-month period were included in the study. To standardize technique and implant type, all patients received saline-filled moderate-profile implants, which were placed partially underneath the pectoralis muscle through a lower pole approach. Photographic analysis of the breast volume was completed preoperatively and, subsequently, at a minimum of six months postoperatively. Preoperatively, each breast was also assigned to one of four classes of increasing mammographic density, as judged by the mammographic radiologist (fatty, moderately dense, heterogeneously dense and extremely dense). Postoperative breast volumes were, subsequently, correlated to mammographic densities. Thirty-eight augmented breasts in 21 patients were examined. The average volume gain based on the implant size used was 92.7%. Heterogeneously dense breasts comprised 68% of the total breasts and showed an average volume gain of 100.67%, extremely dense breasts comprised 26% of the total breasts and showed an average volume gain of 97.3%, and moderately dense breasts comprised 5% of the total breasts with an average gain of 100.04%. There was no significant difference between the augmented breast volumes and the respective expected volumes (combined preaugmented breast volumes and implant volumes; P=0.3483). Additionally, no statistical difference was found between the density classes and the expected augmented volumes. No statistical difference was found between expected and actual augmented breast volumes among or between four different breast density classes. Thus, one would expect that the soft tissue compression or the response of the impression of the implant on the parenchyma, would not be statistically different among classes. Additionally, compressive atrophy, as seen with atrophy of the breasts over time, would be expected to be multifactorial and not uniquely independent to breast density. However, longitudinal analysis is needed to study the durability of breast shape relative to breast density.

Influence of space-filling materials in subantral bone augmentation: blood clot vs. autogenous bone chips vs. bovine hydroxyapatite

The first objective of the present study was to compare the short- and long-term 3D volume stability of sub-sinusal bone regeneration in rabbits using different space fillers. The second objective was to assess qualitatively and quantitatively the early bone formation process and long-term behavior of the regenerated bone. Fifteen rabbits underwent a double sinus lift procedure using: blood clot (Clot), autogenous bone chips (Auto) and bovine hydroxyapatite (BHA). Animals were euthanized at 1 week, 5 weeks and 6 months. Samples were subjected to X-ray microtomography and histology. Variations in the volume of bone augmentations were calculated at different time points. Qualitative analysis was performed using 7 μm sections and quantitative histomorphometric analyses were carried out using scanning electron microscopy. From baseline (100%) to 5 weeks, the augmented volumes declined to 17.3% (Clot), 57.6% (Auto) and 90.6% (BHA). After 6 months, only 19.4% (Clot) and 31.4% (Auto) of initial volumes were found, while it remained more stable in the BHA group (84%). At 1 week, an initial osteogenesis process could be observed in the three groups along the bone walls. At 5 weeks, despite a significant decline in the volume, newly formed bone density was higher with Clot and Auto than with BHA. At 6 months, bone densities were statistically similar in the three groups. However, after 6 months, the surface invaded by newly formed bone (regenerated area) was significantly higher when BHA was used as space filler. In the BHA group, the biomaterial area slightly decreased from 42.7% (1 week) to 40% (5 weeks) and 34.9% (6 months) and the density of the composite regenerated tissue (bone+BHA) reached >50% at 6 months. The three space fillers allowed bone formation to occur. Nevertheless, augmented volumes declined in the Clot and Auto groups, while they remained stable with BHA. A slowly resorbable biomaterial might be suitable in sub-sinusal bone augmentation for preventing the re-expansion process and for augmenting the density of the regenerated tissues.

Complex Sleep Apnea: It Isn't Really a Disease

Complex Sleep Apnea: It Isn't Really a Disease

Lung Volumes and Maximal Respiratory Pressures in Collegiate Swimmers and Runners

To determine whether respiratory muscle strength is related to pulmonary volume differences in athletes and nonathletes, 11 intercollegiate female swimmers, 11 female cross-country runners, and two nonathletic control groups, matched to the athletes in height and age, were evaluated for pulmonary parameters including maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax). Swimmers exhibited larger (p less than .05) vital capacities (VC), residual lung volumes (RV), inspiratory capacities (IC), and functional residual capacities (FRC) than both the runners or the controls but no difference (p greater than .05) in either PImax or inspiratory flow (FIV 25%-75%). Timed expiratory volumes (FEV 0.5 and FEV 1.0) were significantly (p less than .05) lower in the swimmers than in the controls. These data suggest that an adaptational growth may be responsible, in part, for the augmented static lung volumes demonstrated in swimmers.