Sandor G. Vari

Cutting balloon: A novel approach to percutaneous angioplasty☆

Abstract Balloon angioplasty typically injures the vessel wall by inducing irregular intimai tears, splits and stretches.1 Proliferative response to this injury,2 and elastic recoil3 after balloon angioplasty are implicated as causes of restenosis and acute closure, respectively. We hypothesized that sharp and regular endovascular surgical incisions may enhance the success of angioplasty by limiting both injury and elastic recoil. We designed devices to make radially directed, longitudinal surgical cuts from the luminal surface deepening into the medial layer. In this study we used 1 of the possible designs (Figure 1). One to 4 cutting edges of 0.1 to 0.4 mm metal blades were mounted on the surface of balloon catheters parallel with the longitudinal axis of the balloon (cutting balloon). The aims of the study were to (1) determine the immediate morphology of incisions made with the cutting balloon; (2) determine the healing response to the endovascular incisions; and (3) compare angiographie results obtained with standard and cutting balloons.

Effect of Varying Laser Parameters on Pulsed Ho:YAG Ablation of Bovine Knee Joint Tissues

We investigated the effect of varying laser parameters on ablation of fresh bovine knee joint tissues (fibrocartilage, hyaline cartilage, and bone) with a free-running Ho:YAG laser. Ablation rate was measured in saline for each tissue type as a function of laser fluence (160-950 J/cm2), pulse width (150-450 microseconds, full width at half maximum), and fiber core diameter (400 and 600 microns). A weight that was attached to the fiber end was used to exert a constant pressure of 40 g/mm2 to the tissue underneath to ensure a constant contact between the fiber tip and the tissue throughout the ablation process. All tissues could be efficiently ablated, and the ablation rate increased linearly with the fluence. Change in laser pulse width and fiber core diameter resulted in minor variations in the ablation rate for fibro- and hyaline cartilage. On the other hand, use of longer pulses and/or the larger fiber significantly accelerated bone ablation. Histology analysis revealed that zones of thermal damage in Ho:YAG irradiated bovine knee joint tissues differed by tissue types and ranged between 100 and 400 microns, but were independent of fluence, pulse width, and fiber size within the range tested.

Preterm prelabor rupture of membranes (PPROM) is not associated with presence of viral genomes in the amniotic fluid.

BACKGROUND The role of viral infections in preterm prelabor rupture of the membranes (PPROM) is not established. Studies on the presence of viral genomes in the amniotic fluid (AF) collected in pregnancies complicated by PPROM show contradictory outcomes. OBJECTIVES To investigate AF samples of PPROM pregnancies for the presence of viral genomes. STUDY DESIGN AF samples from patients with PPROM were collected during a 4-year (2008-2012) observational study. 174 women were included with selection criteria of singleton pregnancy, PPROM, and maternal age of 18 years and above. PCR was used for detection of human cytomegalovirus (HCMV), herpes simplex virus (HSV), parvovirus B19, human adenoviruses (HAdV), enteroviruses (EV) and human parechovirus (HPeV). The selection of these viral targets was based on literature regarding screening of AF for presence of viral genomes. RESULTS Only a single sample was positive out of the 174 tested AFs, HCMV DNA was detected. CONCLUSIONS PPROM is not associated with active viral infections.

Impact of ovariectomy, high fat diet, and lifestyle modifications on oxidative/antioxidative status in the rat liver

Aim To estimate the impact of high fat diet and estrogen deficiency on the oxidative and antioxidative status in the liver of the ovariectomized rats, as well as the ameliorating effect of physical activity or consumption of functional food containing bioactive compounds with antioxidative properties on oxidative damage in the rat liver. Methods The study was conducted from November 2012 to April 2013. Liver oxidative damage was determined by lipid peroxidation levels expressed in terms of thiobarbituric acid reactive substances (TBARS), while liver antioxidative status was determined by catalase (CAT), glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR) activities, and glutathione (GSH) content. Sixty-four female Wistar rats were divided into eight groups: sham operated and ovariectomized rats that received either standard diet, high fat diet, or high fat diet supplemented with cereal selenized onion biscuits or high fat diet together with introduction of physical exercise of animals. Results High fat diet significantly increased TBARS content in the liver compared to standard diet (P = 0.032, P = 0.030). Furthermore, high fat diet decreased the activities of CAT, GR, and GST, as well as the content of GSH (P < 0.050). GPx activity remained unchanged in all groups. Physical activity and consumption of cereal selenized onion biscuits showed protective effect through increased GR activity in sham operated rats (P = 0.026, P = 0.009), while in ovariectomized group CAT activity was increased (P = 0.018) in rats that received cereal selenized onion biscuits. Conclusion Feeding rats with high fat diet was accompanied by decreased antioxidative enzyme activities and increased lipid peroxidation. Bioactive compounds of cereal selenized onion biscuits showed potential to attenuate the adverse impact of high fat diet on antioxidative status.

Excimer laser (308 nm) recanalisation of in-stent restenosis: thermal considerations.

Abstract. Excimer laser recanalisation of in-stent restenosis may be a viable modality for improving coronary patency. However, the presence of arterial stents modifies the thermal properties of the irradiated area and may alter temperature patterns generated during ablation. The goal of this study was to evaluate, in vitro, temperature changes during excimer laser ablation of stented vessels and compare them with those obtained from unstented (control) vessels. Six different stent types (AVE Microstent-II, AVE-GFX, ACS Multi-link, JJ Palmaz-Schatz, JJ Crown, and NIR) were deployed in freshly excised porcine coronary vessels. Three control unstented samples were also measured. Blood or saline was infused through the vessels, while the tissue environment was kept at ∼37°C. A 308 nm excimer laser (Spectranetics, CVX300) with an eccentric 2.0 mm laser catheter (Spectranetics, EII) delivered two trains of 200 pulses each, 10 s apart, at 60 mJ/mm2, and 40 Hz, simulating maximum clinical exposure. The catheter was positioned midway in the stent, first coaxially parallel to the vessel wall, and then at an angle against the stent and vessel wall. Temperature measurements (n=168 for blood, n=96 for saline) were performed with a ∼210 µm diameter, fast-response thermocouple with 0.1°C resolution. The probe was positioned to within ∼250 µm from the inner surface of the vessels. Tissue temperature was measured at the catheter tip and at the distal and proximal edges of the stents. Maximum recorded temperatures for coaxial and angular alignment, did not exceed 42.2°C (∼6°C above baseline) and 54.2°C (∼18.1°C above baseline) respectively, for all stents types tested, controls, and all probe locations. Both stented and unstented vessels exhibited comparable temperature gradients. The observed maximum temperatures, obtained under extreme lasing conditions, indicated that 308 nm ablation, in the presence of stents under blood or saline infusion, produces clinically acceptable temperatures.

Single acute stress-induced progesterone and ovariectomy alter cardiomyocyte contractile function in female rats

Aim To assess how ovarian-derived sex hormones (in particular progesterone) modify the effects of single acute stress on the mechanical and biochemical properties of left ventricular cardiomyocytes in the rat. Methods Non-ovariectomized (control, n = 8) and ovariectomized (OVX, n = 8) female rats were kept under normal conditions or were exposed to stress (control-S, n = 8 and OVX-S, n = 8). Serum progesterone levels were measured using a chemiluminescent immunoassay. Left ventricular myocardial samples were used for isometric force measurements and protein analysis. Ca2+-dependent active force (Factive), Ca2+-independent passive force (Fpassive), and Ca2+-sensitivity of force production were determined in single, mechanically isolated, permeabilized cardiomyocytes. Stress- and ovariectomy-induced alterations in myofilament proteins (myosin-binding protein C [MyBP-C], troponin I [TnI], and titin) were analyzed by sodium dodecyl sulfate gel electrophoresis using protein and phosphoprotein stainings. Results Serum progesterone levels were significantly increased in stressed rats (control-S, 35.6 ± 4.8 ng/mL and OVX-S, 21.9 ± 4.0 ng/mL) compared to control (10 ± 2.9 ng/mL) and OVX (2.8 ± 0.5 ng/mL) groups. Factive was higher in the OVX groups (OVX, 25.9 ± 3.4 kN/m2 and OVX-S, 26.3 ± 3.0 kN/m2) than in control groups (control, 16.4 ± 1.2 kN/m2 and control-S, 14.4 ± 0.9 kN/m2). Regarding the potential molecular mechanisms, Factive correlated with MyBP-C phosphorylation, while myofilament Ca2+-sensitivity inversely correlated with serum progesterone levels when the mean values were plotted for all animal groups. Fpassive was unaffected by any treatment. Conclusion Stress increases ovary-independent synthesis and release of progesterone, which may regulate Ca2+-sensitivity of force production in left ventricular cardiomyocytes. Stress and female hormones differently alter Ca2+-dependent cardiomyocyte contractile force production, which may have pathophysiological importance during stress conditions affecting postmenopausal women.

Intraoperative metastases detection by laser-induced fluorescence spectroscopy

The authors studied the ability of Laser Induced Fluorescence Spectroscopy (LIFS) for the intraoperative identification of metastases using a photosensitizing agent Photofrin IIr to enhance spectroscopic detection. A He-Cd laser source (442 nm) was used to produce low-power illumination of tissue via a hand-held 400 micrometers fiberoptic probe. Through the same fiber, reflected and emitted light was returned to an optical multi-channel analyzer (OMA III) for analysis. Spectroscopic signals were displayed on a screen for immediate examination. Lobund Wistar rats, inoculated with Pollard rat adenocarcinoma cells, were used as an animal model. Photofrin IIr was administered intraperitoneal 24 or 48 hours prior to surgical exploration in doses varying from 0.75-7.5 mg/kg. Metastases detection was performed during abdominal exploration directed to ipsilateral and contralateral inguinal, iliac, para-aortic and renal lymph nodes. Nineteen tissue samples, identified as abnormal by LIFS, were removed for histologic analysis; 11 of these samples were larger than 5mm and histologic examination revealed malignancy in all cases. While LIFS signals showed malignancy in 8 tissue samples with dimensions less than 5mm, histology confirmed this in only 3. However, serial histologic sections were not performed. From the initial results, it was concluded that LIFS detection of malignant tissue is feasible and enhanced by the addition of Photofrin IIr. LIFS may be a promising technique for the intraoperative detection of primary malignant and metastatic tissue.

Disparities and relative risk ratio of preterm birth in six Central and Eastern European centers.

Aim To identify characteristic risk factors of preterm birth in Central and Eastern Europe and explore the differences from other developed countries. Method Data on 33 794 term and 3867 preterm births (<37 wks.) were extracted in a retrospective study between January 1, 2007 and December 31, 2009. The study took place in 6 centers in 5 countries: Czech Republic, Hungary (two centers), Romania, Slovakia, and Ukraine. Data on historical risk factors, pregnancy complications, and special testing were gathered. Preterm birth frequencies and relevant risk factors were analyzed using Statistical Analysis System (SAS) software. Results All the factors selected for study (history of smoking, diabetes, chronic hypertension, current diabetes, preeclampsia, progesterone use, current smoking, body mass index, iron use and anemia during pregnancy), except the history of diabetes were predictive of preterm birth across all participating European centers. Preterm birth was at least 2.4 times more likely with smoking (history or current), three times more likely with preeclampsia, 2.9 times more likely with hypertension after adjusting for other covariates. It had inverse relationship with the significant predictor body mass index, with adjusted risk ratio of 0.8 to 1.0 in three sites. Iron use and anemia, though significant predictors of preterm birth, indicated mixed patterns for relative risk ratio. Conclusion Smoking, preeclampsia, hypertension and body mass index seem to be the foremost risk factors of preterm birth. Implications of these factors could be beneficial for design and implementation of interventions and improve the birth outcome.

New method for treatment of inferior vena cava tumor thrombus – case study

Conventional surgical therapy for advanced renal venous tumor thrombi results in high morbidity, so there is a need for less invasive techniques. This report presents the first case of a successful inferior vena cava (IVC) tumor thrombus removal without complications with balloon catheter (BC) via internal jugular vein (IJV), called the venous tumor thrombus pushing with balloon catheter (VTTP BC). Under the control of transesophageal echocardiogram and fluoroscope, a balloon catheter was sleeved on the guide wire, which was already inserted into the right internal jugular vein (IJV) and was driven distally above the IVC tumor thrombus. The balloon was inflated to occlude the IVC for prevention of pulmonary embolization. After the occlusion, the guide wire was driven to the cavotomy and was opened at the ostium of the right renal vein. It was pulled at both ends and stretched to serve as a rail. The balloon was gently pushed toward the cavotomy and the thrombectomy was completed. This is a less invasive method for treatment of venous tumor thrombus level 3 that can reduce surgical time, blood loss, and complication rates compared to the existing surgical methods. Also, it can be performed without thoracotomy, cardiopulmonary bypass, hypothermic circulatory arrest, and liver mobilization.

Sex-specific chronic stress response at the level of adrenal gland modified sexual hormone and leptin receptors

Aim To compare cardiometabolic risk-related biochemical markers and sexual hormone and leptin receptors in the adrenal gland of rat males, non-ovariectomized females (NON-OVX), and ovariectomized females (OVX) under chronic stress. Methods Forty six 16-week-old Sprague-Dawley rats were divided into male, NON-OVX, and OVX group and exposed to chronic stress or kept as controls. Weight, glucose tolerance test (GTT), serum concentration of glucose, and cholesterol were measured. Adrenal glands were collected at the age of 28 weeks and immunohistochemical staining against estrogen beta (ERβ), progesterone (PR), testosterone (AR), and leptin (Ob-R) receptors was performed. Results Body weight, GTT, serum cholesterol, and glucose changed in response to stress as expected and validated the applied stress protocol. Stressed males had significantly higher number of ERβ receptors in comparison to control group (P = 0.028). Stressed NON-OVX group had significantly decreased AR in comparison to control group (P = 0.007). The levels of PR did not change in any consistent pattern. The levels of Ob-R increased upon stress in all groups, but the significant difference was reached only in the case of stressed OVX group compared to control (P = 0.033). Conclusion Chronic stress response was sex specific. OVX females had similar biochemical parameters as males. Changes upon chronic stress in adrenal gland were related to a decrease in testosterone receptor in females and increase in estrogen receptor in males.