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Effect of mechanical forces on growth and matrix protein synthesis in the in vitro pulmonary artery
374
CURRENT
LITERATURE
cells. Thus, components in the extracellular matrix, such as fibronectin, laminin, and collagen type IV, may act as regulators of growth and differentiation of keratinocytes. The integrin type extracellular matrix receptors, alpha-2 beta-l collagen receptor, alpha-6 chain of the fibronectin receptor, and alpha-6 chain of the laminin receptor, are transmembrane receptors which are important in cell-cell and cell-matrix interactions. It is speculated that these integrins play an important role in carcinoma metastasis because cell-cell contacts must first be broken. In this study both normal oral squamous epithelium and invasive areas of oral squamous cell carcinoma were evaluated for their expression of extracellular matrix proteins and extracellular matrix receptors (ECM). The presence, quantity and distribution of the extracellular matrix proteins and extracellular matrix integrin type receptors were evaluated in these tissues. Varying concentrations of these ECM proteins and ECM receptors were found in normal mucosa versus oral squamous cell carcinoma. In the mucosa alpha-2 beta-l and alpha-6 were seen at high concentrations at the cell membrane in the basal and supra-basilar cell zones. Alpha-5 was found in a discontinuous fashion at the basal cell-basement membrane interface. In all of the carcinomas, alpha-2 and alpha-6 could be found. In the less differentiated carcinomas alpha-5 was found in low concentrations. Well differentiated carcinomas had a higher alpha-6 concentration than normal mucosa. Less differentiated carcinomas had lower alpha-2 beta-l and alpha6 concentrations and had an increase in cellular proliferation. Thus, low alpha-6 concentrations may become an important marker in grading oral squamous cell carcinomas.L. NEVILLE
Fibrin Sealant Matrix Supports Outgrowth of Peripheral Sensory Axons. Zeng L, Huck S, Red1 H, et al. Stand J Plast Reconstr Hand Surg 29:199, 1995
Reprint Schiller
Instrumentation and Setup for Endoscopic Plastic Surgery. Eaves FF, Bostwick J, Nahai F. Clin Plast Surg 22:591, 1995
requests to Dr Kosmehl: Institute of Pathology, University, D-07740 Jena, Germany.
Friedrich
Effect of Mechanical Forces on Growth and Matrix Protein Synthesis in the In Vitro Pulmonary Artery. Kolpakov V, Rekhter M, Gordon D. Circ Res 77:823, 1995 To study the effects of mechanical forces on pulmonary artery growth and matrix protein synthesis, rabbit arteries were subjected to varying magnitudes of stretch and hydrostatic pressure in vitro. Strips of pulmonary artery were exposed to loads comparable to intramural pressures of 12, 25 or 45 mmHg at a constant hydrostatic pressure of 12 mmHg. In another sample set, wall stress was held constant at 12 mmHg and hydrostatic pressures were tested at 12, 25, and 45 mmHg. Total protein synthesis was measured by quantitative autoradiography using procollagen I amino-terminal monoclonal antibody. Results confirmed a direct relationship between stretch and the rate of protein synthesis in smooth muscle cells. The percentage of procollagen type I positive cells and the rate of cell replication also exhibited a direct relationship with stretch; however, there was no increase in protein synthesis of adventitial fibroblasts. Finally, stretch increased rate of elastin and collagen synthesis where hydrostatic pressure had no significant effect on either smooth muscle cells or fibroblasts. From the data, it was concluded that stretch, not pressure, can stimulate hypertrophy and hyperplasia of smooth muscle cells and fibroblastic hyperplaSk-FRANK
IUORNO
Jr
Reprint requests to Dr Kulik: Division of Pediatric Cardiology, versity of Michigan Hospitals, MCHC F 1310, Box 0204, Arbor, MI 48109-0204.
UniAnn
Fibrin-based sealants have been used in peripheral nerve surgery to provide better coaptation between transected nerve stumps. It has also been postulated that fibrin matrix is essential during the early stages of nerve regeneration. In this study, the authors used a fibrin sealant matrix as a substrate for in vitro neurite elongation and peripheral axon regeneration in vivo. For the in vitro experiment, dissociated embryonic chick sensory neurons were cultured on petri dishes coated with fibrin sealant matrix and compared with a solution of thrombiticalcium chloride, or with poly-Dlysine. At 16 hours, the percentage of neurons which had outsprouted was similar in the fibrin sealant matrix and polyD-lysine groups at 58% and 57%, respectively. In contrast, all neurons plated on the thrombin/calcium chloride solution were dead at 16 hours. For the in vivo experiment, 48 rat sciatic nerves were severed and reanastomosed with two epineural 10-O nylon stitches. Fibrin sealant matrix or phosphate buffer was applied to the repair region. Pinch reflex testing revealed that the regeneration of the leading sensory fiber was markedly increased in the fibrin sealant matrix group at 3 and 4 days over the control group. Based on these results, it seems that fibrin sealant matrix enhances axonal regeneration during the early phase in vivo, and also supports elongation of neurites in vitro.-C.E. PEOPLES Reprint requests to Dr Zeng: Ludwig mental and Clinical Traumatology, 1200 Vienna. Austria.
Boltzmann Institute for ExperiDonaueschingenstrasse 13 A-
Endoscopes were introduced more than a century ago with the development of rigid multilens optical systems. These initial systems were crude, and were composed of a series of lenses in a metallic sheath which allowed visualization of the internal structures through the assistance of incandescent bulbs. In the 196Os, Hopkins inverted the position of interspersing air and lenses. Thus, the optical pathway of the endoscope became a series of long glass lenses. Fiberoptic cables wrapped around the internal optical pathway produced a secondary pathway for the conduction of incoming light. In the 198Os, small sensory chip video cameras were introduced which allowed the image to be placed on a monitor. Finally, video recording technology became helpful for both documentation and teaching. The most common rigid endoscopes for facial procedures are 4.0 to 5.0 mm in diameter and 0 to 30 degrees in viewing. Video imaging systems include the video camera, light source, monitors, and recording devices, and represent the area of greatest potential initial expense when beginning endoscopic procedures. Instruments for developing and maintaining the optical cavity have been developed in the mid-1980s and 1990s and include endoretractors and canulas. Instruments for endoscopic dissection vary widely and are specific for various anatomic regions. Those for the face include elevators, scissors and graspers. Those for the forehead are more curved than for the midface, lowerface and neck. Proper planning and organization in the operating room can expedite endoscopic surgical procedures. This includes the proper surgical plan, electronic video system, endoscope and instruments, a properly positioned endo-
CURRENT
LITERATURE
cells. Thus, components in the extracellular matrix, such as fibronectin, laminin, and collagen type IV, may act as regulators of growth and differentiation of keratinocytes. The integrin type extracellular matrix receptors, alpha-2 beta-l collagen receptor, alpha-6 chain of the fibronectin receptor, and alpha-6 chain of the laminin receptor, are transmembrane receptors which are important in cell-cell and cell-matrix interactions. It is speculated that these integrins play an important role in carcinoma metastasis because cell-cell contacts must first be broken. In this study both normal oral squamous epithelium and invasive areas of oral squamous cell carcinoma were evaluated for their expression of extracellular matrix proteins and extracellular matrix receptors (ECM). The presence, quantity and distribution of the extracellular matrix proteins and extracellular matrix integrin type receptors were evaluated in these tissues. Varying concentrations of these ECM proteins and ECM receptors were found in normal mucosa versus oral squamous cell carcinoma. In the mucosa alpha-2 beta-l and alpha-6 were seen at high concentrations at the cell membrane in the basal and supra-basilar cell zones. Alpha-5 was found in a discontinuous fashion at the basal cell-basement membrane interface. In all of the carcinomas, alpha-2 and alpha-6 could be found. In the less differentiated carcinomas alpha-5 was found in low concentrations. Well differentiated carcinomas had a higher alpha-6 concentration than normal mucosa. Less differentiated carcinomas had lower alpha-2 beta-l and alpha6 concentrations and had an increase in cellular proliferation. Thus, low alpha-6 concentrations may become an important marker in grading oral squamous cell carcinomas.L. NEVILLE
Fibrin Sealant Matrix Supports Outgrowth of Peripheral Sensory Axons. Zeng L, Huck S, Red1 H, et al. Stand J Plast Reconstr Hand Surg 29:199, 1995
Reprint Schiller
Instrumentation and Setup for Endoscopic Plastic Surgery. Eaves FF, Bostwick J, Nahai F. Clin Plast Surg 22:591, 1995
requests to Dr Kosmehl: Institute of Pathology, University, D-07740 Jena, Germany.
Friedrich
Effect of Mechanical Forces on Growth and Matrix Protein Synthesis in the In Vitro Pulmonary Artery. Kolpakov V, Rekhter M, Gordon D. Circ Res 77:823, 1995 To study the effects of mechanical forces on pulmonary artery growth and matrix protein synthesis, rabbit arteries were subjected to varying magnitudes of stretch and hydrostatic pressure in vitro. Strips of pulmonary artery were exposed to loads comparable to intramural pressures of 12, 25 or 45 mmHg at a constant hydrostatic pressure of 12 mmHg. In another sample set, wall stress was held constant at 12 mmHg and hydrostatic pressures were tested at 12, 25, and 45 mmHg. Total protein synthesis was measured by quantitative autoradiography using procollagen I amino-terminal monoclonal antibody. Results confirmed a direct relationship between stretch and the rate of protein synthesis in smooth muscle cells. The percentage of procollagen type I positive cells and the rate of cell replication also exhibited a direct relationship with stretch; however, there was no increase in protein synthesis of adventitial fibroblasts. Finally, stretch increased rate of elastin and collagen synthesis where hydrostatic pressure had no significant effect on either smooth muscle cells or fibroblasts. From the data, it was concluded that stretch, not pressure, can stimulate hypertrophy and hyperplasia of smooth muscle cells and fibroblastic hyperplaSk-FRANK
IUORNO
Jr
Reprint requests to Dr Kulik: Division of Pediatric Cardiology, versity of Michigan Hospitals, MCHC F 1310, Box 0204, Arbor, MI 48109-0204.
UniAnn
Fibrin-based sealants have been used in peripheral nerve surgery to provide better coaptation between transected nerve stumps. It has also been postulated that fibrin matrix is essential during the early stages of nerve regeneration. In this study, the authors used a fibrin sealant matrix as a substrate for in vitro neurite elongation and peripheral axon regeneration in vivo. For the in vitro experiment, dissociated embryonic chick sensory neurons were cultured on petri dishes coated with fibrin sealant matrix and compared with a solution of thrombiticalcium chloride, or with poly-Dlysine. At 16 hours, the percentage of neurons which had outsprouted was similar in the fibrin sealant matrix and polyD-lysine groups at 58% and 57%, respectively. In contrast, all neurons plated on the thrombin/calcium chloride solution were dead at 16 hours. For the in vivo experiment, 48 rat sciatic nerves were severed and reanastomosed with two epineural 10-O nylon stitches. Fibrin sealant matrix or phosphate buffer was applied to the repair region. Pinch reflex testing revealed that the regeneration of the leading sensory fiber was markedly increased in the fibrin sealant matrix group at 3 and 4 days over the control group. Based on these results, it seems that fibrin sealant matrix enhances axonal regeneration during the early phase in vivo, and also supports elongation of neurites in vitro.-C.E. PEOPLES Reprint requests to Dr Zeng: Ludwig mental and Clinical Traumatology, 1200 Vienna. Austria.
Boltzmann Institute for ExperiDonaueschingenstrasse 13 A-
Endoscopes were introduced more than a century ago with the development of rigid multilens optical systems. These initial systems were crude, and were composed of a series of lenses in a metallic sheath which allowed visualization of the internal structures through the assistance of incandescent bulbs. In the 196Os, Hopkins inverted the position of interspersing air and lenses. Thus, the optical pathway of the endoscope became a series of long glass lenses. Fiberoptic cables wrapped around the internal optical pathway produced a secondary pathway for the conduction of incoming light. In the 198Os, small sensory chip video cameras were introduced which allowed the image to be placed on a monitor. Finally, video recording technology became helpful for both documentation and teaching. The most common rigid endoscopes for facial procedures are 4.0 to 5.0 mm in diameter and 0 to 30 degrees in viewing. Video imaging systems include the video camera, light source, monitors, and recording devices, and represent the area of greatest potential initial expense when beginning endoscopic procedures. Instruments for developing and maintaining the optical cavity have been developed in the mid-1980s and 1990s and include endoretractors and canulas. Instruments for endoscopic dissection vary widely and are specific for various anatomic regions. Those for the face include elevators, scissors and graspers. Those for the forehead are more curved than for the midface, lowerface and neck. Proper planning and organization in the operating room can expedite endoscopic surgical procedures. This includes the proper surgical plan, electronic video system, endoscope and instruments, a properly positioned endo-