Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where David A. Jansen is active.

Publication


Featured researches published by David A. Jansen.


Plastic and Reconstructive Surgery | 2006

Evaluation of a Calcium Hydroxylapatite-based Implant (radiesse) for Facial Soft-tissue Augmentation

David A. Jansen; Miles H. Graivier

Background: Soft-tissue fillers have become increasingly prominent in the practice of facial aesthetic medicine. The authors sought to evaluate the long-term clinical efficacy and safety of a calcium hydroxylapatite-based filler (Radiesse) for facial soft-tissue augmentation. Methods: A total of 609 subjects received calcium hydroxylapatite injections in several facial areas: the nasolabial folds, marionette lines, oral commissure, cheeks, chin, lips, and radial lip lines. Follow-up patient satisfaction surveys were conducted at 6 months and again between 12 and 24 months. Treatment satisfaction was based on a scale of 1 (least satisfied) to 5 (most satisfied) using subjective self-evaluation of preoperative photographs. Subjects were also asked whether they would use the treatment again. Adverse events were recorded immediately after treatment and at follow-up visits. Results: Of the total number of survey requests, 155 subjects provided 6-month follow-up data and 112 subjects provided long-term 12- to 24-month data. The average satisfaction rating at 6 months was 3.94. A total of 138 of 155 subjects (89 percent) at 6 months and 83 of 112 (74 percent) at 12 to 24 months stated that they would use the treatment again. The only side effect observed was the development of easily treated nodules, reported by 42 of 338 of lip mucosa augmentation subjects (12.4 percent) and six of 163 of subjects (3.7 percent) who had treatment for radial lip lines. The proportion of subjects with lip nodules decreased to 8.8 percent when the implant volume was decreased. Conclusions: The calcium hydroxylapatite-based implant is a safe, long-lasting, highly effective, and well-tolerated agent for many areas of facial soft-tissue augmentation.


BMC Cancer | 2014

Molecular characterization of exosome-like vesicles from breast cancer cells

Stefan Kruger; Zakaria Y. Abd Elmageed; David H. Hawke; Philipp M. Wörner; David A. Jansen; Asim B. Abdel-Mageed; Eckhard Alt; Reza Izadpanah

BackgroundMembrane vesicles released by neoplastic cells into extracellular medium contain potential of carrying arrays of oncogenic molecules including proteins and microRNAs (miRNA). Extracellular (exosome-like) vesicles play a major role in cell-to-cell communication. Thus, the characterization of proteins and miRNAs of exosome-like vesicles is imperative in clarifying intercellular signaling as well as identifying disease markers.MethodsExosome-like vesicles were isolated using gradient centrifugation from MCF-7 and MDA-MB 231 cultures. Proteomic profiling of vesicles using liquid chromatography-mass spectrometry (LC-MS/MS) revealed different protein profiles of exosome-like vesicles derived from MCF-7 cells (MCF-Exo) than those from MDA-MB 231 cells (MDA-Exo).ResultsThe protein database search has identified 88 proteins in MDA-Exo and 59 proteins from MCF-Exo. Analysis showed that among all, 27 proteins were common between the two exosome-like vesicle types. Additionally, MDA-Exo contains a higher amount of matrix-metalloproteinases, which might be linked to the enhanced metastatic property of MDA-MB 231 cells. In addition, microarray analysis identified several oncogenic miRNA between the two types vesicles.ConclusionsIdentification of the oncogenic factors in exosome-like vesicles is important since such vesicles could convey signals to non-malignant cells and could have an implication in tumor progression and metastasis.


Tissue Engineering | 2002

Differentiation Kinetics of in Vitro 3T3-L1 Preadipocyte Cultures

Hong Song; Kim C. O'Connor; Kyriakos D. Papadopoulos; David A. Jansen

Engineering autologous adipose constructs from cell culture is a promising strategy to overcome limitations of conventional soft-tissue implants. A methodology is presented to experimentally determine and mathematically model the differentiation kinetics of in vitro 3T3-L1 preadipocyte cultures that can aid in construct design. Relative rates of morphological and interfacial events during adipogenesis were compared. Model results suggest that maturation of an intermediate multilocular phenotype was the rate-limiting step in morphological differentiation and had an intrinsic rate of 0.012 day(-1). Dislodgment of multilocular fat cells was the primary mechanism of cell loss during adipogenesis. The maximum rate of lipid droplet nucleation was predicted to precede that of coalescence by 10 days and to be three times faster. Coalescence probability was estimated to decrease from 33 to 11% for 4- and 8-microm-diameter droplets, respectively. Fluid drainage and the cytoskeleton between droplets could have impeded coalescence. The kinetic analysis suggests that droplet ripening was the dominant mechanism of lipid production. Applications of this research include engineering of an adipose construct and predicting surgical outcome of patients requiring soft-tissue augmentation.


Annals of Plastic Surgery | 1996

Human immunodeficiency virus infection and subsequent melanoma.

Kind Gm; VonRoenn J; David A. Jansen; Bailey Mh; Lewis Vl

Immunosuppression has been known for many years to be associated with the development of skin cancer, particularly squamous cell carcinoma. The association with melanoma is less clear. This report describes 4 patients with known human immunodeficiency virus (HIV) positivity who subsequently developed malignant melanoma. The subtypes and precursors of the tumors vary. Three of 4 patients treated using accepted surgical standards remained disease free an average of 33 months postoperatively. Treatment of the melanoma as in the non-HIV infected melanoma patient is advised. Epidemiological studies remain to be done to determine the significance of this association. In the meantime, melanoma remains a surgical disease and early, aggressive, standard surgical treatment is encouraged for these patients. Despite the immunocompromised state that their HIV status implies, surgical treatment offers local and regional control of disease and possibly cure.


Plastic and Reconstructive Surgery | 1999

Changes in compliance predict pulmonary morbidity in patients undergoing abdominal plication.

David A. Jansen; Alan D. Kaye; Ron E. Banister; Atul K. Madan; Karl G. Hyde; Bobby D. Nossaman

The incidence and severity of the effects of pulmonary compliance changes were investigated in patients undergoing abdominal plication surgery. A total of 20 healthy adults scheduled for abdominal plication surgery who had no significant history of pulmonary disease and 20 adults scheduled for nonabdominal, nonthoracic surgery (control group) underwent general endotracheal anesthesia; neuromuscular blockade was confirmed with electrical twitch monitoring. Before abdominal plication, the mean airway compliance was measured under total neuromuscular blockade at 33.4 +/- 2.1 ml/cm water, which was not significant when compared with control patient values. After abdominal plication was performed, the mean airway compliance was remeasured under total neuromuscular blockade; it was significantly decreased at 24.0 +/- 1.8 ml/cm water when compared with values for control patients (32.6 +/- 1.6 ml/cm) and with preplication values. Patients with airway compliance changes of less than 4 ml/cm water (when compared with preplication pulmonary mechanics) had far less incidence of atelectasis, requirements for supplemental oxygen at 24 hours or longer, or hypoxia when compared with patients with compliance changes of greater than 4 ml/cm water. Patients with compliance changes greater than 9 ml/cm water had the highest incidence of pulmonary morbidity. These data suggest that significant changes in pulmonary compliance occur after abdominal plication and that these airway compliance changes are associated with a clinically increased incidence of pulmonary morbidity in the postoperative period.


American Journal of Physiology-heart and Circulatory Physiology | 2014

Intratracheal administration of cyclooxygenase-1-transduced adipose tissue-derived stem cells ameliorates monocrotaline-induced pulmonary hypertension in rats.

Naveen K. Somanna; Philipp M. Wörner; Subramanyam N. Murthy; Edward A. Pankey; Deborah J. Schächtele; Rose-Claire St. Hilaire; David A. Jansen; Abigail E. Chaffin; Bobby D. Nossaman; Eckhard Alt; Philip J. Kadowitz; Reza Izadpanah

The effect of intratracheal administration of cyclooxygenase-1 (COX-1)-modified adipose stem cells (ASCs) on monocrotaline-induced pulmonary hypertension (MCT-PH) was investigated in the rat. The COX-1 gene was cloned from rat intestinal cells, fused with a hemagglutanin (HA) tag, and cloned into a lentiviral vector. The COX-1 lentiviral vector was shown to enhance COX-1 protein expression and inhibit proliferation of vascular smooth muscle cells without increasing apoptosis. Human ASCs transfected with the COX-1 lentiviral vector (ASCCOX-1) display enhanced COX-1 activity while exhibiting similar differentiation potential compared with untransduced (native) ASCs. PH was induced in rats with MCT, and the rats were subsequently treated with intratracheal injection of ASCCOX-1 or untransduced ASCs. The intratracheal administration of ASCCOX-1 3 × 10(6) cells on day 14 after MCT treatment significantly attenuated MCT-induced PH when hemodynamic values were measured on day 35 after MCT treatment whereas administration of untransduced ASCs had no significant effect. These results indicate that intratracheally administered ASCCOX-1 persisted for at least 21 days in the lung and attenuate MCT-induced PH and right ventricular hypertrophy. In addition, vasodilator responses to the nitric oxide donor sodium nitroprusside were not altered by the presence of ASCCOX-1 in the lung. These data emphasize the effectiveness of ASCCOX-1 in the treatment of experimentally induced PH.


Annals of Plastic Surgery | 2016

Refinements in the Techniques of 2-Stage Breast Reconstruction.

Freeman; Vemula R; Rao R; Matatov Ts; Strong Al; Tandon R; Chaffin Ae; David A. Jansen

BackgroundTwo-stage breast reconstruction with tissue expanders is one of the most common plastic surgery procedures. Acellular dermal matrix (ADM) has become popular for its ability to improve expansion parameters and aesthetics, albeit with a higher complication profile. We present data that support redefining 2-stage reconstruction to include tissue expanders regardless of final reconstructive modality to act as a bridge. Furthermore, we show that cooperation with the ablative surgeon and technical refinements support ADM omission from the first stage of reconstruction. MethodsWe retrospectively reviewed charts from the senior authors (D.A.J.) private practice over a 10-year follow-up period. Inclusion criteria included all women over 18 years who underwent mastectomy and had a tissue expander placed immediately or in a delayed fashion and successfully completed tissue expansion and are finished with the second stage of reconstruction or awaiting second stage of reconstruction. Demographic data, tissue expander filling data, final reconstruction, aesthetic outcome, and complications were tabulated. ResultsA total of 118 women (165 breasts) met inclusion criteria. There were no statistically significant differences in initial fill volume (P = 0.094), number of visits until final expansion (P = 0.677), or final fill volume (P = 0.985) between the ADM and non-ADM cohorts. In addition, non-ADM patients had superior aesthetic scores with respect to defects other than scarring (P = 0.015), projection (P = 0.013), and inframammary fold quality (P = 0.009). Fifteen percent of women decided to change desired final reconstruction modality during the tissue expansion phase. ConclusionsThis reconstructive algorithm emphasizes surgical cooperation between the ablative and reconstructive surgeon, improved technique, and patient education. This focus translates into maintained tissue expansion, aesthetically pleasing results, and allows for the omission of ADM from reconstruction.


Aesthetic Plastic Surgery | 2018

Treatment of Breast Animation Deformity in Implant-Based Reconstruction with Selective Nerve Ablation

Dustin L. Eck; David C. Nguyen; Laura L. Barnes; David A. Jansen

Breast animation deformity is a known complication of subpectoral implant placement that is usually corrected by repositioning the implant to the prepectoral position. Other less common treatment options include performing the muscle splitting biplanar technique, triple plane technique, neuromodulator injections, and secondary neurotomies via transection of the pectoral muscle. We report a patient with animation deformity successfully treated with direct identification and ablation of the medial and lateral pectoral nerves using selective bipolar electrocautery. The patient is a woman with a history of invasive ductal carcinoma who underwent bilateral mastectomy and breast reconstruction with subpectoral implant placement and autologous fat grafting. Within 1 year of her breast reconstruction, she developed hyperactive pectoralis muscle contraction with resulting distortion of both breasts. Given the disadvantages of repositioning the implant to the prepectoral position and transecting the pectoralis muscles via secondary neurotomy, we chose to directly identify and selectively ablate distal branches of the medial and lateral pectoral nerves. This offers a novel technique for correcting breast animation deformity without transecting the pectoralis muscles, causing muscle atrophy, and preserving the subpectoral implant position.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the table of contents or the online instructions to authors www.springer.com/00266.


Plastic and reconstructive surgery. Global open | 2017

Outcomes Comparison for Microsurgical Breast Reconstruction in Specialty Surgery Hospitals Versus Tertiary Care Facilities

Rahul Vemula; Matthew J. Bartow; Matt Freeman; Cameron Callaghan; Tim Matatov; David A. Jansen; Bob Allen; Hugo St. Hilaire; Oren Tessler

Background: Postoperative monitoring is crucial in the care of free flap breast reconstruction patients. Tertiary care facilities (TCFs) provide postoperative monitoring in an ICU after surgery. Specialty surgery hospitals (SSHs) do not have ICUs, but these facilities perform free flap breast reconstruction as well. Are outcomes comparable between the 2 facilities in terms of flap reexploration times and overall success? Methods: Retrospective study including 163 SSH and 157 TCF patients. Primary predictor was facility in which the procedure was performed. Secondary predictors included operative, demographic, and comorbidity data. Primary outcomes were flap take back rate and flap failures. Secondary outcomes were total time from adverse event noticed in the flap to returning to the operating room (OR) and total time from decision made to return to the OR to returning to the OR (decision made). Tertiary outcomes were length of stay, operative times, and blood loss. Results: Patients at the TCF were generally less healthy than SSH patients. Salvage rates and failure rates were similar between the 2 institutions. Adverse event noticed and decision made times did not differ between the 2 facilities. Overall flap success rate was 98.22% at SSH and 98.81% at TCF. No primary or secondary predictors had a significant correlation with increased odds for flap failure. Conclusion: SSHs can offer similar outcomes in free flap breast reconstruction with just as effective clinical response times to endangered flaps as found in a TCF. However, surgery at an SSH may best be reserved for healthier patients.


Cuaj-canadian Urological Association Journal | 2016

Management of adult concealed penis using a meshed, split-thickness skin graft

Aaron Boonjindasup; Michael R. Pinsky; Carrie Stewart; Landon Trost; Abigail E. Chaffin; David A. Jansen; Wayne J.G. Hellstrom

INTRODUCTION Concealed penis (CP) is a rare problem faced by urologists and plastic surgeons. CP occurs secondary to trauma, obesity, or infection. Surgical treatment is individualized and based on patient and provider variables. We aim to review our recent experience using meshed split-thickness skin grafting (STSG) for CP management. METHODS A retrospective review was performed on patients who underwent STSG for CP at our institution. Records were reviewed for demographic, operative, and postoperative variables. Preoperative and postoperative photos were obtained to monitor cosmetic results. RESULTS Eleven patients underwent CP release with meshed STSG placement. All cases showed improved functional phallic length and good cosmetic results, regardless of etiology. CONCLUSIONS STSG is a viable option for penile coverage for management of this difficult-to-treat CP population. This primary or salvage modality offers excellent cosmetic results and may be used following prior reconstructive attempts.

Collaboration


Dive into the David A. Jansen's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Kim C. O'Connor

California Institute of Technology

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Landon Trost

University of Rochester

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge