On the evaluation of the antimicrobial effect of grape seed extract and cold atmospheric plasma on the dynamics of Listeria monocytogenes in novel multiphase 3D viscoelastic models

The demand for products that are minimally processed and produced in a sustainable way, without the use of chemical preservatives or antibiotics have increased over the last years. Novel non-thermal technologies such as cold atmospheric plasma (CAP) and natural antimicrobials such as grape seed extract (GSE) are attractive alternatives to conventional food decontamination methods as they can meet the above demands. The aim of this study was to investigate the microbial inactivation potential of GSE, CAP (in this case, a remote air plasma with an ozone-dominated RONS output) and their combination against L. monocytogenes on five different 3D in vitro models of varying rheological, structural, and biochemical composition. More specifically, we studied the microbial dynamics, as affected by 1 % (w/v) GSE, CAP or their combination, in three monophasic Xanthan Gum (XG) based 3D models of relatively low viscosity (1.5 %, 2.5 % and 5 % w/v XG) and in a biphasic XG/Whey Protein (WPI) and a triphasic XG/WPI/fat model. A significant microbial inactivation (comparable to liquid broth) was achieved in presence of GSE on the surface of all monophasic models regardless of their viscosity. In contrast, the GSE antimicrobial effect was diminished in the multiphasic systems, resulting to only a slight disturbance of the microbial growth. In contrast, CAP showed better antimicrobial potential on the surface of the complex multiphasic models as compared to the monophasic models. When combined, in a hurdle approach, GSE/CAP showed promising microbial inactivation potential in all our 3D models, but less microbial inactivation in the structurally and biochemically complex multiphasic models, with respect to the monophasic models. The level of inactivation also depended on the duration of the exposure to GSE. Our results contribute towards understanding the antimicrobial efficacy of GSE, CAP and their combination as affected by robustly controlled changes of rheological and structural properties and of the biochemical composition of the environment in which bacteria grow. Therefore, our results contribute to the development of sustainable food safety strategies.

The antimicrobial efficacy of remote cold atmospheric plasma effluent against single and mixed bacterial biofilms of varying age

Cold atmospheric plasma (CAP) is a minimal food processing technology of increasing interest in the food industry, as it is mild in nature compared to traditional methods (e.g. pasteurisation) and thus can maintain the food's desirable qualities. However, due to this mild nature, the potential exists for post-treatment microbial survival and/or stress adaptation. Furthermore, biofilm inactivation by CAP is underexplored and mostly studied on specific foods or on plastic/polymer surfaces. Co-culture effects, biofilm age, and innate biofilm-associated resistance could all impact CAP efficacy, while studies on real foods are limited to the food product investigated without accounting for structural complexity. The effect of a Remote and Enclosed CAP device (Fourth State Medicine Ltd) was investigated on Escherichia coli and Listeria innocua grown as planktonic cells and as single or mixed bacterial biofilms of variable age, on a biphasic viscoelastic food model of controlled rheological and structural complexity. Post-CAP viability was assessed by plate counts, cell sublethal injury was quantified using flow cytometry, and biofilms were characterised and assessed using total protein content and microscopy techniques. A greater impact of CAP on planktonic cells was observed at higher air flow rates, where the ReCAP device operates in a mode more favourable to reactive oxygen species than reactive nitrogen species. Although planktonic E. coli was more susceptible to CAP than planktonic L. innocua, the opposite was observed in biofilm form. The efficacy of CAP was reduced with increasing biofilm age. Furthermore, E. coli produced much higher protein content in both single and mixed biofilms than L. innocua. Consequently, greater survival of L. innocua in mixed biofilms was attributed to a protective effect from E. coli. These results show that biofilm susceptibility to CAP is age and bacteria dependent, and that in mixed biofilms bacteria may become less susceptible to CAP. These findings are of significance to the food industry for the development of effective food decontamination methods using CAP.

Induction of labor in twin pregnancy after 36 weeks does not increase maternal-fetal morbidity

OBJECTIVE

To compare maternal and perinatal outcomes in twin pregnancy patients without any fetal or maternal disease, managed by labor induction or expectant management after 36 weeks gestation.

METHODS

We conducted a case-control study of 81 patients: labor induction (n=36) vs. expectant management (n=45). Labor was induced using oxytocin (n=18), vaginal prostaglandins (n=6) or intrauterine balloon catheter (n=12) according to the Bishop score. Maternal and perinatal outcome variables were compared among both groups.

RESULTS

The characteristics of the labor induction group and the expectant management group were not statistically different, except for the rate of nulliparae (55.6% vs. 33.3%) and the rate of epidural analgesia (100% vs. 80%). There was no significant difference in labor time (6.5+/-2.8 h vs. 6.0+/-3.6 h), cesarean section rate (8.3% vs. 13.3%) or duration of maternal hospitalization (7.3+/-2.0 days vs. 7.5+/-2.3 days) in the labor induction group and in the expectant management group, respectively. The birth weight was higher in the labor induction group than in the expectant management group (2639+/-352 g vs. 2463+/-298 g, P<0.001). The rate of Apgar score <7 at 5 min was 0% and 3.3%, respectively. Neonatal intensive care unit admission occurred in 30.5% and 26.6% of the groups, respectively. No perinatal death was reported.

CONCLUSION

Induction of labor may be proposed to patients with uneventful twin pregnancy after 36 weeks gestation without increasing maternal-fetal morbidity.

[Endometrial thermocoagulation via balloon: technique, mechanism of action, and evaluation]

Thermal balloon endometrial ablation is indicated for women suffering from menorrhagia. This easy technique can be performed safely, without using operative hysteroscopy. The rate of minor complications is low (< 4%). Thermotherapy treats the endometrium and superficial myometrium tissues without risk of injury to the bladder and bowels. The success rate of this operation is 90% in selected patients of studies published between 1996 and 1998, with a follow-up period of 12-24 months. However, long-term randomized controlled studies are needed to compare thermotherapy and other endometrial ablation procedures.

Management of septate uterus by flexible hysteroscopy and Nd:YAG laser

OBJECTIVE

To evaluate the efficiency of flexible Nd-YAG laser hysteroscopic metroplasty.

METHODS

We present a retrospective study of 17 patients treated for septate uteri between 1990 and 1995. The indication of hysteroscopy was recurrent abortion in nine cases and eight with primary infertility with indication of IVF in another five cases. We did not prescribe any pretreatment. A flexible hysteroscope with a 100-W Nd:YAG laser was used with glycine-controlled flow. The septum was divided by the laser after exploration of the cavity. We proposed a control office hysteroscopy 2 months after surgery to prevent uterine adhesions.

RESULTS

There was no complication. Twelve patients conceived with 10 live births at term and two spontaneous abortions. Four are still infertile, two were lost from the study and two no longer desired pregnancy. Resectoscopic studies showed the same results.

CONCLUSION

The advantages of this method are the excellent ergonomic properties of the fibroscope and the safety of the laser. We suggest that metroplasty does not improve the pregnancy rate but only the pregnancy outcome of these patients. However, for those with the indication of IVF the procedure seems useful in avoiding abortion.

Endometrial Nd-YAG laser ablation by hysterofibroscopy: long-term results of 137 cases

OBJECTIVE

In our gynecology department, we have been performing endometrial laser ablation (ELA) under video control using a flexible hysteroscope since 1989. The aim of this study is to evaluate the long term results of our experience.

STUDY DESIGN

We went back to the files of 137 patients treated between 1989 and 1993. These women (mean age 42 years) exhibited menorrhagia unamenable to medical treatments which had been developing for 28 months. Mean hysterometry was 9.8 cm. A hysteroscopy with ELA was performed. Our procedure lasts 19 min on average and uses 0.9 1 of glycocol. There were no perforations. Six patients presented a fever above 38 degrees C within the next 48 h; only one developed a true endometritis necessitating antibiotherapy. One patient who had received several GnRH agonist courses had a coagulation of the uterus and had to be hysterectomised.

RESULTS

Nine patients were lost to follow-up; for the others, mean follow-up was 32 months. Seventeen women (13.3%) were hysterectomised, including the patient with a coagulation necrosis of the myometrium. In most cases, this was for undetected adenomyosis or fibromas evolving after hysteroscopy. Bleeding recurred in two other patients; they refused hysterectomy but should be counted as failures of this method. Among the 109 patients (85.1%) considered a success, 35 have had menopause since the procedure.

CONCLUSION

ELA is a simple quick procedure which significantly reduces the number of hysterectomies. In addition, the economic value of ELA is beginning to be assessed in the literature. This long-term study should allow the indications to be better defined by eliminating patients with a high risk of failure and should lead to improved results.

Use of provisional prostheses with osseointegration

The ingenuity that has characterized the fabrication of provisional prostheses has been readily adapted to the osseointegration technique. Implant abutments do not need protection during final prosthesis fabrication stages as teeth do. However, compelling arguments can be made in favor of esthetic, comfortable, and functional provisional prostheses supported by implants, even if they are worn for only a few weeks. The prosthodontic contribution to a patient's quality of life throughout all stages of treatment is thereby enhanced.