Control of browning of minimally processed mangoes subjected to ultraviolet radiation pulses

The pulsed ultraviolet radiation (UV_P) has been used as an alternative strategy for the control of microorganisms in food. However, its application causes the browning of minimally processed fruits and vegetables. In order to control the browning of the 'Tommy Atkins' minimally processed mango and treated with UV_P (5.7 J cm^-2) it was used 1-methylcyclopropene (1-MCP) (0.5 μL L^-1), an ethylene action blocker in separate stages, comprising five treatments: control, UV_P (U), 1-MCP + UV_P (M + U), UV_P + 1-MCP (U + M) e 1-MCP + UV_P + 1-MCP (M + U + M). At the 1st, 7th and 14th days of storage at 12 °C, we evaluated the color (L* and b*), electrolyte leakage, polyphenol oxidase, total extractable polyphenols, vitamin C and total antioxidant activity. The 1-MCP, when applied before UV_P, prevented the loss of vitamin C and when applied in a double dose, retained the yellow color (b*) of the cubes. However, the 1-MCP reduced lightness (L*) of independent mango cubes whatever applied before and/or after the UV_P. Thus, the application of 1-MCP did not control, but intensified the browning of minimally processed mangoes irradiated with UV_P.

Early investigation of silver-coated Silzone heart valves prosthesis in 126 patients

BACKGROUND AND AIM OF THE STUDY

Permanent silver (Silzone) coating of the sewing cuff of St. Jude Medical prosthetic heart valves may reduce the rate of prosthetic valve endocarditis (PVE). However, the incidence of paravalvular leaks and stroke in patients after implantation of Silzone-coated heart valve prostheses is largely unknown.

METHODS

Complications were analyzed among 126 consecutive patients (78 males, 48 females; mean age 64.7 years; range: 40-80 years) who received Silzone-coated prostheses at our institution between February 1998 and December 1999. Among patients, 94 had aortic valve replacement, 29 mitral valve replacement, and three had aortic and mitral valve replacement. Concomitant cardiac procedures (mainly coronary bypass) were performed in 47 patients (37.3%).

RESULTS

Hospital mortality was 1.6% (2/126) and freedom from valve-related mortality 99.2+/-0.9%. Total follow up was 137.4 patient-years, and 98.4% complete. Strokes or transitory ischemic attacks (TIAs) occurred in four cases (two strokes, two TIAs; stroke rate 1.5%/year; 95% CI 0.4-2.6%/year; stroke+TIA rate 3%/year; 95% CI 0.4-5.25%/year). There was no case of prosthetic valve dysfunction or PVE. Freedom from reoperation due to procedure-associated complications was 97.6% (one aortic dissection, two major bleeds). Paravalvular leak was detected in 19 cases, and graded trivial or mild in 17 cases (11 grade 0-I, six grade I), and moderate in two cases (grade I-II in one, grade II in one). No patient needed reoperation due to paravalvular leak. Left ventricular (LV) function was normal in 80 cases, but was impaired mildly in 20 cases, moderately in 16, and severely in eight. Bicycle exercise testing in 92 patients (73%) showed median exercise performance (81.4+/-23.9% of normal) after correction for age and weight. Cerebral magnetic resonance imaging was performed in 64 patients (50.8%); median MRI score was 2.0+/-1.8 according to a 12-scaled score system.

CONCLUSION

The overall incidence of echocardiographic paravalvular leak graded more than trivial or mild was low (1.6%) in patients followed for a mean of 1.1+/-0.5 years (range: 1-27 months) after valve replacement with Silzone-coated heart valve prostheses. No patient required reoperation due to paravalvular leak; moreover, the stroke rate (1.5%/year) was low in these patients. The present data indicated no significant disadvantages or higher rate of complications related to silver coating compared with other, non-silver-coated prostheses. Future investigation is needed to determine long-term outcome.

Aortic valve replacement with stentless and stented porcine valves: a case-match study

OBJECTIVES

To assess the potential benefits of the hemodynamic superiority of stentless valves, we conducted a case-match study among patients who underwent aortic valve replacement with two types of porcine bioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis.

METHODS

Preoperative clinical variables predictive of death after aortic valve replacement were determined by a stepwise logistic regression analysis in a series of 908 consecutive patients who received porcine aortic bioprostheses during a 14-year interval. Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independent predictors of death. On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the shortest interval for each matched pair, was 43 +/- 24 months for both groups.

RESULTS

At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.006); the freedom from cardiac-related death was 95% +/- 4% for the Toronto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom from any valve-related complication was 81% +/- 5% for the Toronto SPV and 50% +/- 10% for the Hancock II (p = 0.008). A Cox proportional hazard model demonstrated a significant reduction in cardiac mortality rates and valve-related morbidity in patients who received the Toronto SPV bioprosthesis.

CONCLUSIONS

Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-control study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.

Autologous tissue cardiac valve for aortic valve replacement: technical aspects and early results

BACKGROUND

The known complications of heterograft bioprostheses and homograft valves have renewed the interest in the use of autologous material. A new technique to construct a tissue prosthesis for aortic valve replacement using the patient's pericardium harvested at the time of operation was developed. The glutaraldehyde-tanned pericardium is mounted on a stent requiring no suturing. Intraoperative testing assures adequate valve function.

METHODS

The autologous tissue cardiac valve was implanted in 50 patients in the aortic position between March 1994 and May 1995. Echocardiograms were performed in all patients before hospital discharge, at 3 months (41 patients), and at the end of first postoperative year (12 patients). The mean age was 69.8 +/- 5 years (range, 58 to 82 years). Eighty-four percent of patients presented with aortic stenosis and 16% had a combined lesion. Additional cardiac procedures were performed in 21 patients.

RESULTS

Aortic cross-clamp time was 72 +/- 19 minutes, and bypass time was 97 +/- 28 minutes. There were three in-hospital deaths, and 2 patients died within the first postoperative year. Predischarge echocardiography demonstrated excellent hemodynamics, with a mean gradient of 20 +/- 8 mm Hg and no or trivial aortic insufficiency in 45 patients. One patient had moderate aortic insufficiency. At first follow-up 36 patients (90%) were in New York Heart Association class I and 4 patients were in class II. Echocardiography showed no evidence of valve failure or degeneration (mean gradient, 17 +/- 5mm Hg; aortic insufficiency = grade 0 [trivial] in 35 patients, grade II in 3 patients, and grade III in 1 patient). Similarly, no degeneration or valve failure with increasing aortic insufficiency was seen in the patients studied at the end of the first postoperative year.

CONCLUSIONS

These results demonstrate that an autologous tissue cardiac valve can be manufactured in the operating room without significant additional operating time. Intraoperative testing minimizes the risk of primary failure with aortic insufficiency. Short-term results are encouraging with good hemodynamic performance of the valve and no signs of degeneration. However, long-term durability needs to be demonstrated.

Videoendoscopic procedures in thoracic surgery: technical aspects and report of removal of a mediastinal cyst

Current videoendoscopic technology and percutaneous techniques of exposure and dissection have been successfully applied to abdominal surgery with favorable results. Application of this technology to our practice of thoracic surgery is the basis of this report. Video-assisted thoracic surgery was performed in 36 patients for the following indications: Raynaud's syndrome, undefined pulmonary nodule, persisting spontaneous pneumothorax, T1 bronchial carcinoma, and mediastinal cyst. Videoendoscopic surgical procedures were accomplished using double-lumen endotracheal anaesthesia and a percutaneous stapling device. Procedures performed using this technique include thoracic sympathectomy, wedge or keel excision, blebectomy, lung apex stapling, parietal pleurectomy, and dissection of the mediastinal cyst. Median operating time was 45 min (range, 15 to 90 min). Tissue diagnosis was obtained in all patients. Median diameter of excised nodules was 10 mm (range, 7 to 70 mm). There were no operative deaths. The single complication was a prolonged air leak. This new method of thoracic surgery appears to benefit the patients. For us it proved a secure way to perform thoracic surgery. Our case of removal of a benign cyst in the posterior mediastinum shows that video-assisted thoracic surgery has expanding applications in the field of general thoracic surgery.

Videoendoscopic removal of a mediastinal cyst

A 41-year-old woman was admitted to the hospital for obstetric surgery. A preoperative chest x-ray film showed a mediastinal mass. After examinations with echocardiography, computed tomography, and magnetic resonance imaging, we removed a cyst that was 2.7 x 3.5 cm in size by thoracoscopic means. The patient left the hospital 3 days after the operation.

Clinical in vitro endothelialization of femoropopliteal bypass grafts: an actuarial follow-up over three years

PURPOSE

The creation of an endothelial coverage on prosthetic vascular surfaces may improve the performance of synthetic small diameter vascular grafts. In vitro lining with cultured autologous endothelial cells offers a confluent endothelium at the time of implantation.

METHODS

Between June 1989 and December 1991, 49 patients who had no saphenous vein available entered the study. Indication for operation was disabling claudication in 37 patients and critical ischemia in 12 patients. With a random 1:2 assignment, 33 patients were admitted to the endothelialized group and 16 control patients received an untreated polytetrafluoroethylene prosthesis. Cultured autologous endothelial cells from the external jugular vein were confluently lined onto polytetrafluoroethylene grafts precoated with fibrinolytically inhibited fibrin glue. The follow-up was based on angiography, platelet labeling studies with indium 111-labeled oxine, assessment of the ankle-brachial index, and duplex sonography.

RESULTS

First-passage mass cultures of 16 million endothelial cells-required for the confluent lining of a 70 cm long 6 mm graft-were reached 25.1 +/- 11.2 days after vein excision. Growth failure occurred in 27.3%. After 32 months, the actuarial patency was 84.7% for endothelialized grafts and 55.4% for control grafts (p < 0.041 by Breslow test; p < 0.068 by Mantel-Cox test). The ankle-brachial index was continually diverging, reaching significantly lower values in the control group at 24 months (0.98 +/- 0.14 in the endothelialized group versus 0.70 +/- 0.12 in the control; p < 0.0023). The uptake of indium 111-labeled platelets--measured at 9 days, 3 months, 6 months, and 12 months--was significantly lower in the endothelialized group during the entire observation period.

In vitro endothelialization of a mesosystemic shunt: a clinical case report

The existence of a confluently covering endothelium that is free of any thrombotic appositions can be proved 30 days after clinical implantation of an in vitro endothelialized expanded polytetrafluoroethylene graft. The recipient of the mesosystemic H-graft was a 69-year-old man who had a thrombosed portal vein following pancreatitis. Autologous endothelial cells were obtained from the external jugular vein under local anesthesia, applying the in situ cannulation technique. After low-density plating, first-passage mass cultures of 1.22 x 10(6) endothelial cells were obtained 14 days after vein excision. After precoating was accomplished with fibrinolytically inhibited fibrin glue, a 10 mm expanded polytetrafluoroethylene graft was confluently lined with the autologous endothelial cells at a seeding density of 1.2 x 10(5) cells/cm2. After a maturation period of an additional 9 days and the microbiologic exclusion of a possible infection, an 11 cm graft segment was implanted between the superior mesenteric vein and the inferior vena cava. In spite of a patent shunt the patient had a repeat bleeding episode, needed parenteral nutrition, and died of sepsis on day 30. Immediately after the graft had been taken out, specimens were processed by scanning electron microscopy and light microscopy for the immunohistochemical proof of the endothelial nature of the surface-covering cell layer. The entire graft surface displayed a confluent cell lining that was free of any thrombotic appositions. A strongly positive stain result for both factor VIII-related antigen and the fixation-resistant CD34 molecule identified these cells as endothelial. No alpha-actin-positive cells could be detected. The underlying protein matrix was well preserved and unaltered in thickness and appearance, compared with preimplantation samples. None of the specimens showed any evidence of infection. This human demonstration of an intact endothelium on a patent venous prosthesis further establishes in vitro lining as a method that actually creates a persistent and functioning endothelium on a synthetic graft surface.

Ethylene production by suspension-cultured pear fruit cells as related to their senescence

Suspension-cultured pear fruit cells produce low levels of ethylene during growth and division in auxin containing medium. When deprived of auxin, division gradually ceases and ethylene production falls to barely discernible levels. However, notable ethylene production can now be induced by indoleacetic acid, CuCl(2), or 1-aminocyclopropane-1-carboxylic acid. If the auxin-deprived cells are transferred to ;aging' medium that lacks auxin but contains 0.4 molar mannitol, inducible ethylene production increases several-fold reaching levels of 40 to 60 nanoliters/10(6) cells per hour. Maximum inducible ethylene productivity is attained at varying times (1-6 days) after transfer to aging medium and appears to be temporally related to cell survival, i.e. the time of subsequent cell death. It is argued that auxin depletion initiates senescence which, in turn, leads to a transient increase in inducible ethylene production and eventual death. The limitations and potentials of the suspension-cultured pear cells as a system for the study of cellular senescence are discussed.

Ethylene production by auxin-deprived, suspension-cultured pear fruit cells in response to auxins, stress, or precursor

Auxin-deprived, mannitol-supplemented, suspension-cultured pear (Pyrus communis L. Passe Crassane) fruit cells produce large quantities (20-40 nanoliters ethylene per 10(6) cells per hour) of ethylene in response to auxins, CuCl(2) or 1-amino-cyclopropane-1-carboxylic acid (ACC). Maximum rates of production are achieved about 12 hours after the addition of optimal amounts of indoleacetic acid (IAA), naphthalene acetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D), 4 to 5 hours after the addition of CuCl(2) and 1 to 2 hours after the addition of ACC. Supraoptimal concentrations of IAA result in a lag phase followed by a normal response. High concentrations of NAA and 2,4-D result in an early (4-5 hours) stress response and injury.Continuous protein and RNA synthesis are essential for elaboration of the full IAA response; only protein synthesis is necessary for the response to CuCl(2) and ACC. Based on polysomal states and rates of amino acid incorporation, CuCl(2) partially inhibits protein synthesis while nonetheless stimulating ethylene production. In general, ethylene production by the pear cells resembles that of other plant systems. Some differences may reflect the sensitivity of the cells and are discussed. The relatively high levels of ethylene produced and the experimental convenience of the cultured cells should make them especially suitable for further investigations of ethylene production and physiology.