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Jian Farhadi

Publications and source records attributed to Jian Farhadi.

10 recordsLinked to original sources
PubMed2006

Reconstruction of the nipple-areola complex: an update.

Along with continuing progress in reconstructive surgery of the breast numerous techniques of nipple-areola reconstruction have been developed. With time and experience some methods have been discredited to historical significance only while others have evolved to widely accepted concepts used by surgeons all over the world, which in turn contributed new ideas and modifications. In addition to those favourite techniques others are reserved as second-line alternatives in specific situations. The principle criterion for a pleasing nipple-areola complex is symmetry regarding several parameters: colour, texture, size, and projection. The purpose of this manuscript is to review and discuss the concepts and techniques of nipple-areola reconstruction that have evolved over the past decades. Furthermore, those principles and techniques are pointed out that fulfil best the criteria of an ideal nipple-areola complex with emphasis on different techniques of breast reconstruction and individual conditions of the patient.

Esthetics↗
PubMed2006

Angiogenesis in tissue engineering: breathing life into constructed tissue substitutes.

Long-term function of three-dimensional (3D) tissue constructs depends on adequate vascularization after implantation. Accordingly, research in tissue engineering has focused on the analysis of angiogenesis. For this purpose, 2 sophisticated in vivo models (the chorioallantoic membrane and the dorsal skinfold chamber) have recently been introduced in tissue engineering research, allowing a more detailed analysis of angiogenic dysfunction and engraftment failure. To achieve vascularization of tissue constructs, several approaches are currently under investigation. These include the modification of biomaterial properties of scaffolds and the stimulation of blood vessel development and maturation by different growth factors using slow-release devices through pre-encapsulated microspheres. Moreover, new microvascular networks in tissue substitutes can be engineered by using endothelial cells and stem cells or by creating arteriovenous shunt loops. Nonetheless, the currently used techniques are not sufficient to induce the rapid vascularization necessary for an adequate cellular oxygen supply. Thus, future directions of research should focus on the creation of microvascular networks within 3D tissue constructs in vitro before implantation or by co-stimulation of angiogenesis and parenchymal cell proliferation to engineer the vascularized tissue substitute in situ.

Animals↗
PubMed2006

Anatomical basis and clinical application of the infragluteal perforator flap.

BACKGROUND: When selecting flaps for coverage of pressure ulcers of the sacrum and perineal region in paraplegic patients, long-term high recurrence rates should be considered. Therefore, the authors developed an infragluteal perforator flap to avoid "burning bridges" for future reconstruction. METHODS: Infragluteal perforator flaps were dissected in five fresh human cadavers to define the anatomy of the cutaneous branches of the descending branch of the inferior gluteal artery and cluneal nerves and define anatomical landmarks for clinical application. In a series of 13 paraplegic patients, the authors used perforator-based flaps (additional skin bridge) to cover four perineal ulcers and one sacral ulcer and perforator flaps to cover six perineal and two sacral ulcers. Donor sites were closed by direct approximation. RESULTS: Twelve of 13 flaps healed uneventfully. In all cadaver and clinical dissections, one or two cutaneous branches of the descending branch of the inferior gluteal artery and one or two cluneal nerves were found at the lower border of the gluteus maximus muscle supplying the infragluteal perforator flap. These direct cutaneous branches allowed dissection of inferior gluteal perforator flaps with improved flap mobility compared with the perforator-based flaps. The descending branch of the inferior gluteal artery could always be spared for future flaps. CONCLUSIONS: The infragluteal perforator flap is a versatile and reliable flap for coverage of ischial and sacral pressure sores. It can be designed as a perforator-based or perforator flap and could provide a sensate flap in ambulatory patients. Donor-site morbidity is minimal, and options for future flaps of the gluteal and posterior thigh region are preserved.

Adult↗
PubMed2006

High magnification assessment improves complete resection of facial tumors.

Complete resection with minimal sacrifice of healthy skin is the goal in treatment of basal cell carcinoma (BCC) of the face. In a randomized trial, preoperative assessment of tumor extension with the Varioscope, a combination of microscope and loupe glasses with strong illumination and a maximal magnification of 7X, was compared with tumor assessment without. Forty consecutive, primary BCC of the solid subtype of the face were randomly assigned to the study groups. Preoperative tumor marking was done by a surgeon not involved in tumor resection, reconstruction, and patient follow-up. All BCC marked with the high magnification were completely excised in the first resection. In the control group, frozen section was used in 12 tumors and permanent section in the remaining 8. The first resection did not yield tumor-free margins as assessed in the frozen section analysis in 3 tumors. In 2 of 8 tumors not supported by frozen section analysis, incomplete excision was detected, and 1 case of false-negative frozen section analysis occurred. In conclusion, the use of high magnification resulted in a trend towards reduction of positive tumor margins in the subgroups that were performed under either intraoperative frozen section or permanent, fixed section histology control, and a significant reduction in tumor-positive margins of all first resections. This was attributed to enhanced preoperative tumor visualization by high (7X) loupe magnification and additional lighting.

Aged↗
PubMed2006

Precultivation of engineered human nasal cartilage enhances the mechanical properties relevant for use in facial reconstructive surgery.

OBJECTIVE: To investigate if precultivation of human engineered nasal cartilage grafts of clinically relevant size would increase the suture retention strength at implantation and the tensile and bending stiffness 2 weeks after implantation. SUMMARY BACKGROUND INFORMATION: To be used for reconstruction of nasal cartilage defects, engineered grafts need to be reliably sutured at implantation and resist to bending/tension forces about 2 weeks after surgery, when fixation is typically removed. METHODS: Nasal septum chondrocytes from 4 donors were expanded for 2 passages and statically loaded on 15 x 5 x 2-mm size nonwoven meshes of esterified hyaluronan (Hyaff-11). Constructs were implanted for 2 weeks in nude mice between muscle fascia and subcutaneous tissue either directly after cell seeding or after 2 or 4 weeks of preculture in chondrogenic medium. Engineered tissues and native nasal cartilage were assessed histologically, biochemically, and biomechanically. RESULTS: Engineered constructs reproducibly developed with culture time into cartilaginous tissues with increasing content of glycosaminoglycans and collagen type II. Suture retention strength was significantly higher (3.6 +/- 2.2-fold) in 2-week precultured constructs than in freshly seeded meshes. Following in vivo implantation, tissues further developed and maintained the original scaffold size and shape. The bending stiffness was significantly higher (1.8 +/- 0.8-fold) if constructs were precultured for 2 weeks than if they were directly implanted, whereas tensile stiffness was close to native cartilage in all groups. CONCLUSION: In our experimental setup, preculture for 2 weeks was necessary to engineer nasal cartilage grafts with enhanced mechanical properties relevant for clinical use in facial reconstructive surgery.

Adult↗
PubMed2005

Differentiation-dependent up-regulation of BMP-2, TGF-beta1, and VEGF expression by FGF-2 in human bone marrow stromal cells.

BACKGROUND: Bone tissue formation by bone marrow stromal cells may be supported and enhanced by multiple growth factors, particularly in cases of a compromised local microenvironment. In this study, the authors hypothesized that fibroblast growth factor (FGF)-2 can stimulate the production by human bone marrow stromal cells of osteogenic [i.e., bone morphogenetic protein (BMP)-2 and transforming growth factor (TGF)-beta1] and angiogenic [i.e., vascular endothelial growth factor (VEGF)] factors. METHODS: Human bone marrow stromal cells from six donors were expanded for two passages (expansion phase) and subsequently cultivated in osteogenic medium containing ascorbic acid, beta-glycerophosphate, and dexamethasone (differentiation phase). After each phase, cells were transferred into serum-free medium with or without FGF-2 at different concentrations and for different times, and the expression of BMP-2, TGF-beta1, and VEGF was quantified at the mRNA level by real-time quantitative reverse-transcriptase polymerase chain reaction. The amounts of TGF-beta1 and VEGF released in the culture medium were assessed using enzyme-linked immunosorbent assay kits and normalized to the DNA content. RESULTS: In response to 5 ng/ml FGF-2 for 24 hours, the mRNA expression of VEGF increased at both culture phases (up to 6.1 fold), whereas that of BMP-2 and TGF-beta1 significantly increased only after the expansion (3.1-fold) or differentiation phase (2.1-fold), respectively. Similar trends were observed in the amounts of proteins measured in the culture medium. CONCLUSIONS: The authors' results indicate that FGF-2 up-regulates the expression of BMP-2, TGF-beta1, and VEGF in human bone marrow stromal cells, in a pattern dependent on the cell-differentiation stage. These findings prompt for in vivo investigations on the delivery of FGF-2 for the temporally/functionally regulated enhancement of bone marrow stromal cell-based bone induction.

Bone Marrow Cells↗
PubMed2005

In vitro osteogenic differentiation and in vivo bone-forming capacity of human isogenic jaw periosteal cells and bone marrow stromal cells.

OBJECTIVE: To compare the in vitro osteogenic differentiation and in vivo ectopic bone forming capacity of human bone marrow stromal cells (BMSCs) and jaw periosteal cells (JPCs), and to identify molecular predictors of their osteogenic capacity. SUMMARY BACKGROUND DATA: JPC could be an appealing alternative to BMSC for the engineering of cell-based osteoinductive grafts because of the relatively easy access to tissue with minimal morbidity. However, the extent of osteogenic capacity of JPC has not yet been established or compared with that of BMSC. METHODS: BMSCs and JPCs from the same donors (N = 9), expanded for 2 passages, were cultured for 3 weeks in osteogenic medium either in monolayers (Model I) or within 3-dimensional porous ceramic scaffolds, following embedding in fibrin gel (Model II). Cell-fibrin-ceramic constructs were also implanted ectopically in nude mice for 8 weeks (Model III). Cell differentiation in vitro was assessed biochemically and by real-time RT-PCR. Bone formation in vivo was quantified by computerized histomorphometry. RESULTS: JPCs had lower alkaline phosphatase activity, deposited smaller amounts of calcium (Model I), and expressed lower mRNA levels of bone sialoprotein, osteopontin, and osterix (Models I and II) than BMSCs. JPCs produced ectopic bone tissue at lower frequency and amounts (Model III) than BMSCs. Bone sialoprotein, osteopontin, and osterix mRNA levels by BMSCs or JPCs in Model II were markedly higher than in Model I and significantly more expressed by cells that generated bone tissue in Model III. CONCLUSIONS: Our data indicate that JPCs, although displaying features of osteogenic cells, would not be as reliable as BMSCs for cell-based bone tissue engineering, and suggest that expression of osteoblast-related markers in vitro could be used to predict whether cells would be osteoinductive in vivo.

Adult↗
PubMed2001

Cell differentiation by mechanical stress.

Growth factors, hormones, and other regulatory molecules are traditionally required in tissue engineering studies to direct the differentiation of progenitor cells along specific lineages. We demonstrate that mechanical stimulation in vitro, without ligament-selective exogenous growth and differentiation factors, induces the differentiation of mesenchymal progenitor cells from the bone marrow into a ligament cell lineage in preference to alternative paths (i.e., bone or cartilage cell lineages). A bioreactor was designed to permit the controlled application of ligament-like multidimensional mechanical strains (translational and rotational strain) to the undifferentiated cells embedded in a collagen gel. The application of mechanical stress over a period of 21 days up-regulated ligament fibroblast markers, including collagen types I and III and tenascin-C, fostered statistically significant cell alignment and density and resulted in the formation of oriented collagen fibers, all features characteristic of ligament cells. At the same time, no up-regulation of bone or cartilage-specific cell markers was observed.

Animals↗
PubMedDate not supplied

Cell yield, proliferation, and postexpansion differentiation capacity of human ear, nasal, and rib chondrocytes.

Human ear, nasal, and rib chondrocytes were compared with respect to their suitability to generate autologous cartilage grafts for nonarticular reconstructive surgery. Cells were expanded for two passages in medium containing 10% fetal bovine serum without (control) or with transforming growth factor beta(1) (TGF-beta(1)), fibroblast growth factor 2 (FGF-2), and platelet-derived growth factor bb (PDGF-bb) (TFP). Expanded cells were cultured as three-dimensional pellets in chondrogenic serum-free medium containing insulin, dexamethasone, and TGF-beta(1). Chondrocytes from all three sources were successfully isolated, increased their proliferation rate in response to TFP, and dedifferentiated during passaging. Redifferentiation by ear and nasal, but not rib, chondrocytes was enhanced after TFP expansion, as assessed by the significant increase in glycosaminoglycan (GAG)/DNA content and collagen type II mRNA expression in the resulting pellets. TFP-expanded ear and nasal chondrocytes generated pellets of better quality than rib chondrocytes, as assessed by the significantly higher GAG/DNA content and collagen type II mRNA expression, and by the relative stain intensities for GAG and collagen types I and II. In conclusion, postexpansion cell yields suggest that all three sources investigated could be used to generate autologous grafts of clinically relevant size. However, ear and nasal chondrocytes, if expanded with TFP, display superior postexpansion chondrogenic potential and may be a preferred cell source for cartilage tissue engineering.

Adolescent↗