Mussel mimetic tissue adhesive for fetal membrane repair: initial in vivo investigation in rabbits.

OBJECTIVE: Iatrogenic preterm prelabour rupture of fetal membranes (iPPROM) remains the main complication after invasive interventions into the intrauterine cavity. The aim of this study was to evaluate the sealing capability and tissue interaction of mussel-mimetic tissue adhesive (mussel glue) in comparison to fibrin glue on punctured fetal membranes in vivo. STUDY DESIGN: A mid-gestational rabbit model was used for testing the materials. The fetal sacs of pregnant rabbits at day 23 were randomly assigned into experimental groups: unoperated (negative control), unclosed puncture (positive control), commercially available fibrin glue (FG) with decellularized amnion scaffold (DAM), mussel glue (MG) with DAM, or mussel glue alone. Evaluation was done at term (30 days' gestation) assessing fetal survival, fetal membrane integrity and histology of the membranes. RESULTS: Fetal survival was not significantly lower in any of the treatment groups compared to the negative control. All plugging materials could be found at the end of the pregnancy and no adverse effects on the fetus or the pregnant does could be observed. Sac integrity was higher in all treatment groups compared to the positive control group but significant only in the FG+DAM group. Cellular infiltration could be seen in fibrin glue and DAM in contrast to mussel glue which was only tightly adhering to the surrounding tissue. These cells were mostly of mesenchymal phenotype staining positive for vimentin. CD68 positive macrophages were found clustered around all the plugging materials, but their numbers were only significantly increased for the mussel glue alone group compared to negative controls. CONCLUSIONS: Mussel glues performance in sealing fetal membranes in the rabbit model was comparable to that of fibrin glue. Taking into account its other favorable properties, it is a noteworthy candidate for a clinically applicable fetal membrane sealant.

Second harmonic generation microscopy of fetal membranes under deformation: normal and altered morphology.

INTRODUCTION: Insight into the microstructure of fetal membrane and its response to deformation is important for understanding causes of preterm premature rupture of the membrane. However, the microstructure of fetal membranes under deformation has not been visualized yet. Second harmonic generation microscopy, combined with an in-situ stretching device, can provide this valuable information. METHODS: Eight fetal membranes were marked over the cervix with methylene blue during elective caesarean section. One sample per membrane of reflected tissue, between the placenta and the cervical region, was cyclically stretched with a custom built inflation device. Samples were mounted on an in-situ stretching device and imaged with a multiphoton microscope at different deformation levels. Microstructural parameters such as thickness and collagen orientation were determined. Image entropy was evaluated for the spongy layer. RESULTS: The spongy layer consistently shows an altered collagen structure in the cervical and cycled tissue compared with the reflected membrane, corresponding to a significantly higher image entropy. An increased thickness of collagenous layers was found in cervical and stretched samples in comparison to the reflected tissue. Significant collagen fibre alignment was found to occur already at moderate deformation in all samples. CONCLUSIONS: For the first time, second harmonic generation microscopy has been used to visualize the microstructure of fetal membranes. Repeated mechanical loading was shown to affect the integrity of the amnion-chorion interface which might indicate an increased risk of premature rupture of fetal membrane. Moreover, mechanical loading might contribute to morphological alterations of the fetal membrane over the cervical region.

Mussel-mimetic tissue adhesive for fetal membrane repair: an ex vivo evaluation.

Iatrogenic preterm prelabor rupture of membranes (iPPROM) remains the main complication after invasive interventions into the intrauterine cavity. Here, the proteolytic stability of mussel-mimetic tissue adhesive (mussel glue) and its sealing behavior on punctured fetal membranes are evaluated. The proteolytic degradation of mussel glue and fibrin glue were compared in vitro. Critical pressures of punctured and sealed fetal membranes were determined under close to physiological conditions using a custom-made inflation device. An inverse finite element procedure was applied to estimate mechanical parameters of mussel glue. Mussel glue was insensitive whereas fibrin glue was sensitive towards proteolytic degradation. Mussel glue sealed 3.7mm fetal membrane defect up to 60mbar (45mmHg) when applied under wet conditions, whereas fibrin glue needed dry membrane surfaces for reliable sealing. The mussel glue can be represented by a neo-Hookean material model with elastic coefficient C(1)=9.63kPa. Ex-vivo-tested mussel glue sealed fetal membranes and resisted pressures achieved during uterine contractions. Together with good stability in proteolytic environments, this makes mussel glue a promising sealing material for future applications.

Comparison of the performance of hip implants with data from different arthroplasty registers.

This study evaluated the feasibility of using published data from more than one register to define the performance of different hip implants. In order to obtain estimates of performance for specific types of hip system from different register, we analysed data from the annual reports of five national and one Italian regional register. We extracted the number of implants and rates of implant survival at different periods of follow-up. Our aim was to assess whether estimates of cumulative survival rate were comparable with data from registers from different countries, and our conclusion was that such a comparison could only be performed incompletely.

Intragastric balloon: another option for treatment of obesity and morbid obesity.

BACKGROUND/AIMS: The BioEnterics Intragrastric Balloon (BIB, BioEnterics, Santa Barbara, CA) in association with restricted diet has been used for the treatment of obesity and morbid obesity. METHODOLOGY: Since March 1998, 349 BIB were placed in 303 obese and morbidly obese patients; 95 patients were male and 208 female; mean age was 41.5 years (19-70); mean weight was 118.8 Kg (67-229); mean BMI was 42 Kg/m2, % excess weight was 62.3% (4.6-216.3). The balloon was inserted and removed endoscopically under general anesthesia. Patients were given a balanced diet of 1000 Kcal/day. RESULTS: After 4 months of balloon treatment, the mean weight loss was 13.9 Kg and the mean reduction in BMI was 4.8 Kg/m2. Weight loss was greater in male patients. Weight loss was accompanied by an improvement of the diseases associated with obesity, in particular diabetes. CONCLUSIONS: The best indications for BIB were: morbidly obese (BMI >40) and super-obese patients (BMI >50) in preparation for bariatric operations; obese patients with BMI 35-40 with co-morbidity in preparation for bariatric surgery; obese patients with BMI 30-35 with a chronic disease otherwise unresolved; patients with BMI <30 only in a multidisciplinary approach.

Treatment of morbid obesity with intragastric balloon in association with diet.

BACKGROUND: The BioEnterics Intragastric Balloon (BIB, BioEnterics, Santa Barbara, CA) in association with restricted diet has been used for the treatment of obesity and morbid obesity. METHODS: Since March 1998, 322 BIB were placed in 281 obese and morbidly obese patients; 73 patients were male and 208 female; mean age was 41.6 years (21-70); mean weight was 117.4 kg (67-229); mean BMI was 41.8 kg/m2 (29-81); % excess weight was 62% (10-216). The balloon was inserted and removed endoscopically under general anesthesia. Patients were given a balanced diet of 1000 kcal/day. Also, for 18 months we compared 42 obese patients treated only with 1000 kcal/day diet (group A) with 31 obese patients subjected to BIB for 4 months + 1000 kcal/day diet (group B). RESULTS: After 4 months of balloon treatment, the mean weight loss was 13.9 kg and the mean reduction in BMI was 4.8. Weight loss was greater in male patients. Weight loss was accompanied by an improvement of the diseases associated with obesity, in particular diabetes. In the diet vs BIB + diet study, BIB with diet produced a greater weight loss in a shorter time than diet alone. CONCLUSION: The best indications for BIB were: morbidly obese opatients (BMI > 40) and super-obese patients (BMI > 50) in preparation for bariatric operations; obese patients with BMI 35-40 with co-morbilities in preparation for bariatric surgery; obese patients with BMI 30-35 with a chronic disease otherwise unresolved; patients with BMI < 30 only in a multidisciplinary approach.

Noradrenaline induced secretion of nonelectrolytes through frog skin.

Addition of noradrenaline (4 x 10(-5) M) to the inner bathing fluid in the skin of the frog Rana esculenta results in increased unidirectional fluxes of urea, thiourea, N-methyl-thiourea, N-N'-dimethylthiourea and mannitol. Fluxes towards the external medium (phi o) undergo a much greater increase than those moving the opposite direction (phi i). The effect of noradrenaline on phi o is higher for urea and thiourea than mannitol, while its effect on phi o thiourea derivatives is related to lipid solubility. This phenomenon does not occur for phi i of the same molecules. FCCP (10(-6) M) pretreatment strongly inhibits the noradrenaline effect on phi o. In skin pretreated with colchicine (2 x 10(-5) M) both urea fluxes are increased to the same extent by noradrenaline. Noradrenaline is concluded to exert two separate effects: (1) a change in permeability in both directions; (2) a secretion of nonelectrolytes towards the external fluid. Such secretion is most probably associated with the hormone-induced secretion of fluid and electrolytes, perhaps mediated by an exocytotic mechanism.