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Biomedical subjects

J Peter Rubin

Publications and source records attributed to J Peter Rubin.

15 recordsLinked to original sources
PubMed2007

Completing the metamorphosis: building a center of excellence in postbariatric plastic surgery.

Postbariatric body contouring is an expanding and rapidly evolving specialty within plastic surgery. To best address the many clinical issues related to the safe and effective care of the postbariatric patient, the authors have established a dedicated multidisciplinary treatment center. Team building efforts have brought together attending plastic surgeons who specialize in body contouring, nurses focused on body contouring after weight loss, and an administrative staff well trained in the issues related to managing these specific types of cases. Through core partnerships, nutritionists, lifestyle counselors, and psychologic professionals are present in the clinic to evaluate patients alongside the plastic surgeon. A dedicated physician assistant and body-contouring fellow work in both the clinic and the operating room (OR). This team approach has allowed for the establishment of defined screening procedures and patient care algorithms. Outreach and patient education initiatives have allowed the center to forge strong alliances with the regional bariatric surgeons and make patients aware of the role of plastic surgery as they start the process of weight loss. A strong research mission is demonstrated by an IRB-approved clinical registry and database that facilitate outcomes studies.

Algorithms↗
PubMed2006

Peptide-surface modification of poly(caprolactone) with laminin-derived sequences for adipose-derived stem cell applications.

Human adipose tissue has been recognized as a source of adult stem cells for tissue engineering applications such as bone, cartilage, and soft tissue repair. For the success of these tissue-engineering approaches, a cell delivery vehicle such as a hydrogel or scaffold is required to position the stem cells at the site of need. Surface modification techniques have been instrumental in the development of scaffolds that promote cell-surface interactions. In this study, poly(caprolactone) (PCL), surfaces were modified in order to promote the attachment and proliferation of adipose-derived stem cells (ASCs). RGD, YIGSR, and IKVAV peptide sequences derived from the extracellular matrix protein laminin were each covalently attached to an aminated polymer surface using carbodiimide chemistry. The surface was characterized using scanning electron microscopy (SEM), goniometry and X-ray photoelectron spectroscopy (XPS). The attachment and proliferation of ASCs was assessed on the different peptide-treated surfaces. XPS analysis confirmed the presence of the peptide sequences on the surface of the polymer as indicated by the increase in the nitrogen/carbon ratio on the surface of the polymer. Among all peptide sequences tested, IKVAV-treated surfaces had a significantly greater number of ASCs bound 2 and 3 days after cell seeding. SEM confirmed differences in the morphology of the cells attached to the three peptide-treated surfaces. These results indicate that IKVAV is a suitable peptide sequence for use in surface modification techniques aimed at improving the attachment of ASCs to a tissue-engineered scaffold.

Adipocytes↗
PubMed2006

Body image and quality of life in post massive weight loss body contouring patients.

OBJECTIVE: Because post-bariatric surgery patients undergo massive weight loss, the resulting skin excess can lead to both functional problems and profound dissatisfaction with appearance. Correcting skin excess could improve all these corollaries, including body image. Presently, few data are available documenting body image and weight-related quality of life in this population. RESEARCH METHODS AND PROCEDURES: Eighteen patients who underwent both bariatric surgery and body contouring completed our study. Both established surveys and new surveys designed specifically for the study were used to assess body perception and ideals, quality of life, and mood. Patients were surveyed at the following time-points: pre-body contouring (after massive weight loss) and both 3 and 6 month post-body contouring. Statistical testing was performed using Student's t test and ANOVA. RESULTS: The mean age of the patients was 46 +/- 10 years (standard deviation). Quality of life improved after obesity surgery and was significantly enhanced after body contouring. Three months after body contouring, subjects ascribed thinner silhouettes to both current appearance and ideal body image. Body image also improved with body contouring surgery. Mood remained stable over 6 months. DISCUSSION: Body contouring after surgical weight loss improved both quality-of-life measurements and body image. Initial body dissatisfaction did not correlate with mood. Body contouring improved body image but produced dissatisfaction with other parts of the body, suggesting that as patients become closer to their ideal, these ideals may shift. We further developed several new assessment methods that may prove useful in understanding these post-surgical weight loss patients.

Analysis of Variance↗
PubMed2006

Assessment of TRAM aesthetics: the importance of subunit integration.

BACKGROUND: Characterization of optimal aesthetics in transverse rectus abdominis musculocutaneous (TRAM) breast reconstruction is a challenge that even the most experienced breast surgeon faces. Aesthetic assessment in breast surgery has attempted to evaluate the reconstructed breast either as one cohesive entity or as a sum of its parts. The authors propose that the most advantageous assessment involves looking at the reconstructions in terms of aesthetic components, not necessarily in visual subunits. METHODS: The authors investigated the responses of five physicians and 12 nonphysician evaluators using various methods of aesthetic assessment, including, most importantly, a visual analogue scale survey. Pearson's correlation and intraclass correlation analyses were performed using SAS software. RESULTS: Their analysis determined that while all components of TRAM reconstruction were important, symmetry, contour, and breast positioning were consistently named the most important components of breast reconstruction. When the breast reconstruction was divided into aesthetic subunits, there was a high degree of correlation between the overall score and the subunit scores (r = 0.81: r > 0.6 for good correlation). CONCLUSIONS: From these assessments, the authors derived a set of aesthetic rules for TRAM flap reconstruction. They believe that methodical application of these rules on a consistent basis can lead to the production of maximal aesthetic outcomes in TRAM breast reconstruction.

Esthetics↗
PubMed2006

A novel perfluoroelastomer seeded with adipose-derived stem cells for soft-tissue repair.

BACKGROUND: There is a need for engineered soft tissue in reconstructive surgery, particularly after tumor removal. An ideal implant that will provide structural support and a favorable environment for growing cells is a key element in the process of tissue engineering. Nonbiodegradable materials that become well incorporated within the new tissue are a good solution, but many such materials do not have a surface favorable for cell adherence and proliferation. The authors hypothesized that the modification of the pore size in a novel fluoropolymer would improve the adherence and enhance the proliferation of adipose-derived stem cells. METHODS: Fluoropolymers with two varying pore size ranges were examined. Fluoropolymer compound U48 (pore size, 100 to 180 microm) and fluoropolymer compound P54 (pore size, 10 to 55 microm) were seeded with human adipose-derived stem cells, and cell adherence to the material was measured after 4 hours and cell proliferation was measured after 72 hours. Cell-seeded constructs were implanted subcutaneously in a nude mouse model for 30 days. RESULTS: Fluoropolymer surface treatment with fibronectin improved the attachment of adipose-derived stem cells to the well plates but did not improve attachment to the fluoropolymer, regardless of pore size. Fluoropolymer U48 increases the adherence and provides a favorable surface for proliferation of adipose-derived stem cells. CONCLUSIONS: After subcutaneous implantation into nude mice, tissue growth was observed in the fluoropolymer samples with the larger pore size. The characteristics of this new material will allow for future clinical applications in plastic and reconstructive surgery.

Adipose Tissue↗
PubMed2006

The osteogenic potential of adipose-derived stem cells for the repair of rabbit calvarial defects.

INTRODUCTION: Bone replacement is often necessary during reconstruction of craniofacial anomalies or trauma. Adipose-derived stem cells (ASCs) possess osteogenic potential and are a promising cell source for bone tissue engineering. The present study was designed to assess the osteogenic potential and utility of using ASCs to regenerate bone in a rabbit calvarial defect model. METHODS: Rabbit ASCs were seeded on gelatin foam (GF) scaffolds and induced in osteogenic medium containing bone morphogenetic protein (BMP)-2. Thirty-four 8-mm calvarial defects were randomly treated with autograft, no treatment, GF scaffold, GF + ASCs, or GF + osteoinduced ASCs. After 6 weeks, calvaria were harvested and underwent histologic and radiologic analyses to compare healing between the treatment groups. RESULTS: Defects treated with autograft underwent complete healing. Radiologically, there were no significant (P > 0.05) differences in healing among empty defects, and those treated with GF alone or GF plus osteoinduced ASCs. Osteoinduced ASCs exhibited significantly (P < 0.05) greater healing than noninduced ASCs. CONCLUSION: Preimplantation osteoinduction of ASCs enhances their osteogenic capacity. Lack of a significant osteogenic effect of ASCs on calvarial healing at 6 weeks may be secondary to use of noncritical-sized defects. Larger defects would likely demonstrate the osteogenic potential of ASCs more definitively.

Adipose Tissue↗
PubMed2006

Regulation of alpha-smooth muscle actin protein expression in adipose-derived stem cells.

The objective of this work was to study the response of adipose-derived stem cells (ASCs) to exogenous biochemical stimulation, and the potential of ASCs to differentiate toward the smooth muscle cell (SMC) lineage. Immunofluorescence staining and Western blot analysis detected protein expression of the early SMC marker alpha-smooth muscle actin (alpha-SMA) in both control and experiment groups. Expression of alpha-SMA in ASCs significantly increased when treated with transforming growth factor-beta1, while alpha-SMA expression only slightly increased in the presence of retinoic acid (RA), beta-mercaptoethanol and ascorbic acid. Treatment with platelet-derived growth factor-BB, RA and dibutyryl-cyclic adenosine monophosphate decreased the expression of alpha-SMA significantly. While beta-mercaptoethanol and ascorbic acid, as well as RA have resulted in increased alpha-SMA expression in marrow-derived mesenchymal stem cells and other progenitor cells, our results demonstrate that these treatments do not significantly increase alpha-SMA expression, indicating that the differentiation potential of ASCs and mesenchymal stem cells may be fundamentally different.

Actins↗
PubMed2005

CD4+ T cell responses elicited by different subsets of human skin migratory dendritic cells.

Skin dendritic cells (DC) are professional APC critical for initiation and control of adaptive immunity. In the present work we have analyzed the CD4+ T cell stimulatory function of different subsets of DC that migrate spontaneously from human skin explants, including CD1a+CD14- Langerhans' cells (LC), CD1a-CD14- dermal DC (DDC), and CD1a-CD14+ LC precursors. Skin migratory DC consisted of APC at different stages of maturation-activation that produced IL-10, TGF-beta1, IL-23p19, and IL-12p40, but did not release IL-12p70 even after exposure to DC1-driving stimuli. LC and DDC migrated as mature/activated APC able to stimulate allogeneic naive CD4+ T cells and to induce memory Th1 cells in the absence of IL-12p70. The potent CD4+ T cell stimulatory function of LC and DDC correlated with their high levels of expression of MHC class II, adhesion, and costimulatory molecules. The Th1-biasing function of LC and DDC depended on their ability to produce IL-23. By contrast, CD1a-CD14+ LC precursors migrated as immature-semimature APC and were weak stimulators of allogeneic naive CD4+ T cells. However, and opposite of a potential tolerogenic role of immature DC, the T cell allostimulatory and Th1-biasing function of CD14+ LC precursors increased significantly by augmenting their cell number, prolonging the time of interaction with responding T cells, or addition of recombinant human IL-23 in MLC. The data presented in this study provide insight into the function of the complex network of skin-resident DC that migrate out of the epidermis and dermis after cutaneous immunizations, pathogen infections, or allograft transplantation.

Antigen-Presenting Cells↗
PubMed2005

Rapid absorption of tumescent lidocaine above the clavicles: a prospective clinical study.

BACKGROUND: Tumescent local anesthesia has been adapted for surgery of the face and neck, but there are no data regarding drug absorption when tumescent injection is used in this region. The aim of this study was to characterize the changes in plasma lidocaine concentrations over time when a tumescent solution is injected into the subcutaneous tissue of the neck. The study was carried out in human volunteer subjects, and injection of lidocaine to the thighs provided control data. METHODS: Eight healthy female volunteer subjects were studied twice using a prospective, crossover design. Tumescent lidocaine solution was injected into the subcutaneous tissue of the neck in one session and the thighs in another session. The order of injection was randomized. Blood samples were collected for 14 hours after injection, and the plasma concentration of lidocaine measured. The injected solution consisted of lidocaine 0.1%, NaHCO3 12.5 mEq/L, and epinephrine 1:1,000,000 in normal saline. A standardized dose of lidocaine (7 mg/kg) was used for each injection and no surgical procedure was performed. RESULTS: All subjects completed the study. Subject weight was 66.1 +/- 12.8 kg, body fat was 29.0 +/- 4.7 percent, and body mass index was 23.8 +/- 3.1 kg/m2. The average time to reach peak lidocaine concentration after neck injection was 5.8 hours, whereas peak lidocaine concentration after thigh injection did not occur until 12.0 hours. This difference of 6.2 hours was highly significant (p = 0.009). The average peak concentration after neck injection was 16 percent greater than that after thigh injection (0.94 microg/ml versus 0.81 microg/ml), with the difference approaching significance (p = 0.06). No adverse reactions were noted. CONCLUSIONS: Tumescent injection above the clavicles results in a rapid rise in plasma lidocaine concentration when compared with injection to the lower extremities. Toxic symptoms could occur much earlier than expected for lower extremity tumescent anesthesia. In addition, dangerous plasma levels could occur if tumescent anesthesia in the lower extremities is followed by tumescent injection above the clavicles, because the absorption curves would be superimposed.

Absorption↗
PubMed2005

The potential of adipose-derived adult stem cells as a source of neuronal progenitor cells.

Adipose-derived adult stem cells are a population of mesenchymal stem cells extracted from discarded adipose tissue. Many have reported the differentiation of adipose-derived stem cells into chondrocytes, myocytes, osteoblasts, and, most recently, neural progenitor cells. This article covers the current state of the potential of the differentiation of adipose-derived stem cells into neuronal cells and an overview of their potential as adult stem therapies for neurological disorders. It has been reported that adipose-derived stem cells are capable of undergoing neuronal differentiation using protocols similar to that of Woodbury et al., which reported the differentiation of bone marrow stromal cells specifically into neurons. However, the transdifferentiation of bone marrow stromal cells into neuronal cells has recently fallen under intense criticism, which will likely place the plasticity of adipose-derived stem cells under scrutiny as well. To date, no group has produced evidence that adipose-derived stem cells are capable of differentiating to mature, functional neuronal cells in vitro. However, recent in vivo studies with adipose-derived stem cells are promising.

Adipocytes↗
PubMed2005

A classification of contour deformities after bariatric weight loss: the Pittsburgh Rating Scale.

BACKGROUND: Contour deformities after massive weight loss are diverse and often severe in nature. Current progress has necessitated a valid, accessible, and comprehensive rating system that correlates appearance and appropriate surgical treatment. Presently, no existing rating system addresses the breadth and variety of deformities that can occur or allows for adequate postsurgical evaluation. METHODS: The authors reviewed full-body photographs of over 300 female patients seen between October of 2002 and May of 2004. The authors targeted body areas most frequently demonstrating skin and soft-tissue laxity and ptosis. A 10-region, four-point grading system was designed to describe the common deformities found in each region of the body. To validate the scale, 12 trained observers applied the rating scale to photographs of 25 patients who showed the 10 regions. Each grading scale ranged from 0, indicating normal, to 3, indicating the most severe deformity. Repeat testing was performed at 2 weeks. Interobserver validity and test-retest reliability were determined using weighted kappa analysis. RESULTS: In all 10 categories, the kappa value was 0.6 or higher (0.6 = threshold for good validity), with a mean kappa value of 0.68 (range, 0.61 to 0.78) and an overall agreement of 69 percent over two sessions. All 12 observers scored an individual mean kappa value of greater than 0.6, indicating good interobserver validity. A given observer had a mean 67 percent agreement, indicating reasonable test-retest reliability. CONCLUSIONS: The Pittsburgh Rating Scale is a validated measure of contour deformities after bariatric weight loss. This scale may have applications in preoperative planning and evaluating surgical outcomes.

Abdomen↗
PubMed2004

Perioperative management of the post-gastric-bypass patient presenting for body contour surgery.

Bariatric surgery has evolved as an effective and relatively safe treatment for morbid obesity. With nearly every region of the body as a potential operative site and an unprecedented number of surgical procedures available, we must give attention to thoughtful perioperative management. Bariatric surgery is a life-changing event for the morbidly obese patient, and the body contouring that follows weight loss often has an equally profound effect. Plastic surgeons must strive to maintain the highest level of safety in this pursuit. The authors address issues surrounding preoperative evaluation and measures to minimize the risk of complications.

Comorbidity↗
PubMed2004

Correcting the saddlebag deformity in the massive weight loss patient.

Skin redundancy of the trunk and thigh is treated by a circumferential abdominoplasty and a lower body lift. Despite preservation and tight approximation of the subcutaneous facial system, the authors have failed to adequately correct severe saddlebag deformity and midthigh laxity in the massive weight loss patient. The technique used in the last nine of the senior author's 43 lower body lifts was modified by fully abducting each operated thigh on a side utility table, before closure in the prone position. This maneuver permits an increase in width of skin excision and causes the lateral thigh skin to be taut upon leg adduction. This is a retrospective review of the senior surgeon's experience over a 3-year period. Postoperative follow-up of the nine-patient cohort ranged from 8 to 12 months. A standardized set of six-view preoperative and postoperative photographs was available for each patient. A regional grading system was developed to assign points for deformity seen in preoperative and postoperative photographs. To compare the effect of the new technique on the correction of hip/lateral thigh deformities, the authors used this same grading system to analyze 10 other lower body lift patients treated by the same surgeon without full thigh abduction who had six sets of standardized photographs. A deformity severity score was determined for each anatomic region by four trained observers blinded to the surgical technique. The nonparametric Mann-Whitney U test using exact p values was used to compare preoperative and percentage change in deformity severity score from preoperative to postoperative scores relative to preoperative scores for each anatomical region among subjects in each treatment group. The nonparametric Wilcoxon signed rank test using exact p values was used to evaluate the change in deformity severity score from preoperative to postoperative values. The change in technique resulted in an observable symmetrical correction of the severe saddlebag deformity and better contour to the distal lateral thighs. All evaluated patients were satisfied with the lateral thigh skin contour. The grading system revealed that patients treated with or without intraoperative thigh abduction had similar preoperative deformity severity scores for each anatomic region (p > 0.05). Postoperatively, all subjects showed improvement in scores for all treated regions. However, patients closed during full thigh abduction had significantly lower deformity severity scores for the hip/thigh complex when compared with patients treated without full thigh abduction (p < 0.05). Complications in these 19 patients consisted of one 6-cm superficial skin layer dehiscence due to a broken polyester suture that healed spontaneously. There were three seromas that responded to a short series of aspirations or catheter drainage. There were no infections. Distal abdominal flap tip skin necrosis in four patients responded to outpatient débridement and healed secondarily. A new grading system for body contour deformities was successfully utilized to judge differences in the quality of trunk and thigh deformity and outcome in 19 patients with adequate photographic records. Tight suture closure in full thigh abduction in the prone position results in improved treatment of significant saddlebag deformity and midthigh skin laxity in the massive weight loss patient. The essential principles are meticulous planning, careful isolation, tight closure of the lateral trunk and thigh subcutaneous fascial system, and artistic contouring of remaining tissues. Dehiscence, undesirable scarring, and seromas were minor issues in the entire group of 43 patients.

Abdomen↗
PubMedDate not supplied

Scientific basis for the use of hypotonic solutions with ultrasonic liposuction.

BACKGROUND: A number of plastic surgeons have advocated using hypotonic solution in ultrasound lipoplasty, theorizing that induced adipocyte swelling increases membrane susceptibility to ultrasonic disruption. Additionally, it has been theorized that potassium increases membrane permeability. This study aimed to determine the effect of solution osmolality on adipocyte diameter, the time course of hypotonic solution action, and the effect of potassium addition on adipocyte diameter. METHODS: Base solutions with three different osmolalities were prepared: normal saline (NS) (154 mOsm/l), 1/2NS (77 mOsm/l), and 1/4NS (38.5 mOsm/l). Each solution was modified to contain 0, 5, and 10 mEq/l of potassium and adjusted to starting osmolality. Adipocytes of six patients were suspended in the nine solutions, and diameters were determined at 0, 15, 30, and 45 min. Diameters were measured using imaging software (Kodak ID 3.6). RESULTS: At time 0, the average adipocyte diameter was 79 +/- 8 microm, and no difference was seen in any of the solutions. Cells in the NS group showed no significant increase in diameter over 45 min. The 1/2NS group achieved an 8% +/- 1.9% increase in diameter at 45 min (p < 0.05). The 1/4NS group showed an increase by 14% +/- 2.4% (p < 0.01) at 15 min, and 15% +/- 2.3% (p < 0.01) at 45 min. Potassium had no independent effect on cell diameter. CONCLUSIONS: Hypotonic solution can significantly increase human adipocyte diameter. The findings showed that 1/2NS had a significant effect within 15 min. Tumescent solutions with an osmolality of 1/4NS may be useful in facilitating ultrasonic lipoplasty.

Adipocytes↗