Performance analysis of a new hypersonic vitrector system.

PURPOSE: To evaluate porcine vitreous flow and water flow rates in a new prototype hypersonic vitrectomy system compared to currently available pneumatic guillotine vitrectors (GVs) systems. METHODS: Two vitrectors were tested, a prototype, ultrasound-powered, hypersonic vitrector (HV) and a GV. Porcine vitreous was obtained within 12 to 24 h of sacrifice and kept at 4°C. A vial of vitreous or water was placed on a precision balance and its weight measured before and after the use of each vitrector. Test parameters included changes in aspiration levels, vitrector gauge, cut rates for GVs, % ultrasound (US) power for HVs, and port size for HVs. Data was analysed using linear regression and t-tests. RESULTS: There was no difference in the total average mean water flow between the 25-gauge GV and the 25-gauge HV (t-test: P = 0.363); however, 25-gauge GV was superior (t-test: P < 0.001) in vitreous flow. The 23-gauge GV was only more efficient in water and vitreous removal than 23-gauge HV needle-1 (Port 0.0055) (t-test: P < 0.001). For HV, wall thickness and gauge had no effect on flow rates. Water and vitreous flows showed a direct correlation with increasing aspiration levels and % US power (p<0.05). CONCLUSIONS: The HV produced consistent water and vitreous flow rates across the range of US power and aspiration levels tested. Hypersonic vitrectomy may be a promising new alternative to the currently available guillotine-based technologies.

Ultrastructural and histopathologic findings after pars plana vitrectomy with a new hypersonic vitrector system. Qualitative preliminary assessment.

PURPOSE: Preliminary assessment of a new prototype ultrasound-based hypersonic vitrector (HV) by qualitatively examining the histopathological changes in the retina and vitreous body after pars plana vitrectomy (PPV) and its ability to fragment vitreous collagen. METHODS: Fourteen porcine cadaveric eyes, 20 eyes in live swine and six human cadaveric eyes underwent PPV using the HV or a pneumatic guillotine vitrector (GV). An additional 4 porcine crystalline lenses were touched with either the HV or GV for 1 minute. Following PPV, human vitreous was removed and processed for electron microscopy (EM). Eyes and lenses were fixed and sectioned for light microscopy (LM). RESULTS: There were no macroscopic retinal or optic nerve defects associated with either HV or GV PPVs. Cadaveric retinal specimens showed separation of the inner limiting membrane (ILM) and vacuolization and fragmentation at the nerve fiber layer (NFL) and the ganglion cell layer (GCL). ILM fragmentation and separation were found after PPV in live swine with both vitrectors. Small disruptions of the posterior capsule or structural lens defects were found after HV touch. The EM analysis revealed more fragmentation of human vitreous collagen fibrils after HV compared to GV PPV. CONCLUSIONS: LM and EM analysis of retina, vitreous, and crystalline lens after PPV showed similar morphological changes using the HV or the GV. Vitreous fragmentation appeared more effective with the HV. Overall this study suggests that the HV may be a promising new technology. More work is needed to quantitatively assess its safety and efficacy.

The suitability of corneas stored by organ culture for penetrating keratoplasty and influence of donor and recipient factors on 5-year graft survival.

PURPOSE: To determine the impact of donor factors on the suitability of corneas stored by organ culture for penetrating keratoplasty (PK) and the influence of donor and recipient factors on 5-year survival of first PK. METHODS: Logistic regression analyses were carried out to determine the influence of donor factors on, respectively, the risk of microbial contamination during organ culture, the suitability of corneas for PK (endothelial cell density ≥ 2200 cells/mm(2)), and the quality of corneas (endothelial cell density ≥ 2500 cells/mm(2)). Only one cornea, randomly selected, from each donor was included in these analyses. A Cox regression analysis was used to determine the influence of donor and recipient factors on 5-year PK survival. RESULTS: Risk of contamination (n = 8317): Causes of donor death including infection, respiratory disease, and cancer all increased the risk of contamination during organ culture (P < 0.0001). Suitability for PK and endothelial quality (n = 7107): Donor age (P < 0.0001) and storage time in organ culture (P < 0.0001) were the principal factors affecting suitability and quality. Death to enucleation and enucleation to processing times had little influence. Corneas from organ donors were more likely to be suitable for PK (P = 0.0003). Five-year graft survival (n = 3014): Graft survival was dominated by the indication for PK (P < 0.0001). Allograft rejection was also a major risk factor for failure (P < 0.0001). The only donor factor affecting survival was sex (P = 0.008). CONCLUSIONS: Donor age and storage time but not postmortem times influenced the suitability of corneas for PK. The indication for PK and other recipient factors were the main predictors of graft failure.

Sodium caseinate induces expression and secretion of murine multipotent myeloid cell line 32D macrophage colony-stimulating factor.

BACKGROUND: Evidence that sodium caseinate (CasNa) is capable of inhibiting proliferation of hematopoietic precursor cell line 32D and inducing its differentiation into macrophage cells has recently been published. Taking into consideration that hematopoiesis is regulated by growth factors and that macrophage colony-stimulating factor (M-CSF) is a well-known growth factor that induces differentiation of macrophages, in this work we evaluated whether CasNa is capable of inducing expression and secretion of M-CSF in 32D cells. METHODS: We cultured 32D cells in presence and absence of CasNa and compared their proliferation and viability. RNA was extracted from cell lysates to evaluate expression of the gene for M-CSF and its receptor. Cultured conditioned media was used to evaluate presence of M-CSF. RESULTS: Our results showed that CasNa inhibited proliferation of 32D cells and that conditioned media (CM) of these cultures contained M-CSF-like activity. Presence of M-CSF in CM was detected by inhibiting M-CSF activity with anti-M-CSF and presence of this growth factor was confirmed by ELISA assay. We also provided evidence that CasNa induced expression of mRNA for M-CSF in 32D cells as well as increased expression of mRNA for its receptor. CONCLUSIONS: CasNa inhibits proliferation of 32D cells and induces expression of the gene for M-CSF and that of its receptor. It also induces secretion of the bioactive form of M-CSF.

El caseinato de sodio induce la diferenciación de las células hematopoyéticas multipotenciales 32D / Sodium caseinate induces differentiation of the multipotential hemopoietic cell line 32D

Objetivo. Evaluar la participación del caseinato de sodio (CasNa) en la modulación de la hematopoyesis. Material y métodos. Se emplearon células 32D, una línea celular hematopoyética multipotencial, de origen murino y dependiente de interleucina-3. Estas células se cultivaron con 0.5 ng/mL de interleucina-3 y con concentraciones variables de CasNa. En los cultivos se realizaron estudios de proliferación celular (conteo directo e incorporación de timidina 3H) y de diferenciación morfológica (tinción con Giemsa), citoquímica (tinciones específicas para monocito-macrófagos y para granulocitos) y funcional (presencia de receptores Fc y reducción de nitro azul de tetrazolio), además se determinó la viabilidad con azul de tripano y la apoptosis por la reacción Tunel in situ. Resultados. Se demostró que el CasNa produce una reducción en la proliferación, dependiente de la dosis, que ésta no es provocada por una disminución de la viabilidad de las células 32D así como tampoco por un aumento de la muerte celular por apoptosis. Además el CasNa indujo la diferenciación de las células 32D hacia monocito-macrófagos en cultivos de 4 días. Conclusiones. Aparentemente el CasNa ejerce una actividad tipo factor estimulador de colonias de macrófagos. Además, parece ser un potente factor de diferenciación de las células 32D, ya que en sólo 4 días de estímulo genera células de tipo monocito-macrófago, a diferencia de los 7 días requeridos por la combinación de G-CSF y GM-CSF.