Rapid and Robust Surface Treatment for Simultaneous Solid and Liquid Repellency

A wide range of liquid and solid contaminants can adhere to everyday functional surfaces and dramatically alter their performance. Numerous surface modification strategies have been developed that can reduce the fouling of some solids or repel certain liquids but are generally limited to specific contaminants or class of foulants. This is due to the typically distinct mechanisms that are employed to repel liquids vs solids. Here, we demonstrate a rapid and facile surface modification technique that yields a thin film of linear chain siloxane molecules covalently tethered to a surface. We investigate and characterize the liquid-like morphology of these surfaces in detail as the key contributing factor to their anti-fouling performance. This surface treatment is extremely durable and readily repels a broad range of liquids with varying surface tensions and polarities, including water, oils, organic solvents, and even fluorinated solvents. Additionally, the flexible, liquid-like nature of these surfaces enables interfacial slippage, which dramatically reduces adhesion to various types of solids, including ice, wax, calcined gypsum, and cyanoacrylate adhesives, and also minimizes the nucleation of inorganic scale. The developed surfaces are durable and simple to fabricate, and they minimize fouling by both liquids and solids simultaneously.

Novel Omniphobic Platform for Multicellular Spheroid Generation, Drug Screening, and On-Plate Analysis

Multicellular spheroids are superior to other culture geometries in reproducing critical physiological conditions of tumors, such as the diffusion of oxygen, nutrients, waste, and drugs, leading to a more precise model of in vivo drug sensitivity and resistance. Previously reported spheroid culture platforms are often difficult to use, expensive, single-use, or mechanically unstable. Here, we report a facile, mechanically stable, high-throughput spheroid culture platform based on hierarchically textured omniphobic surfaces. The developed omniphobic surfaces display very high contact angles with a range of different liquids, including the cell-laden culture media, thereby minimizing the cell surface contact area. Additionally, these surfaces maintain these high contact angles for extended periods of time to ensure cell aggregation. Using this novel platform, we demonstrate the generation and maintenance of robust multicellular spheroids, as well as heterogeneous, multicell-type spheroids. The platform is extremely robust, resistant to mechanical shock, allows for on-plate imaging, and is also the first-ever spheroid generation platform that can be reused repeatedly. Finally, the platform is suitable for on-plate drug screening and enables the first-ever, on-plate immunofluorescence staining and imaging of spheroids.

Non-Fluorinated, Superhydrophobic Binder-Filler Coatings on Smooth Surfaces: Controlled Phase Separation of Particles to Enhance Mechanical Durability

There has been a recent drive to develop non-fluorinated superhydrophobic coatings due to the toxicity, cost, and environmental impact of perfluorinated components. One of the main challenges in developing superhydrophobic coatings in general and non-fluorinated superhydrophobic coatings in particular is optimization of mechanical durability, as the rough asperities required for maintaining superhydrophobicity tend to be easily removed by abrasion. Although rough and self-similar hydrophobic surfaces composed of loosely adhered particles or highly porous structures tend to produce excellent superhydrophobicity, they have low inherent mechanical durability and their longevity under real conditions is compromised. To address this issue, this work investigates the addition of a polymeric matrix material (the binder) to hydrophobic nanoparticles (the filler) to produce spray-coated superhydrophobic surfaces with improved inherent mechanical durability. Hansen solubility parameters were used to tune the interactions between the binder, filler, and solvent used to deliver the coating. It was found that lowering the binder/filler miscibility and using a poor solvent mixture generates more surface roughness, thereby lowering the minimum filler load required to achieve superhydrophobicity. This leads to an overall more inherently durable system that remains hydrophobic for thousands of light abrasion cycles.

Lysis and direct detection of coliforms on printed paper-based microfluidic devices

Coliforms are one of the most common families of bacteria responsible for water contamination. Certain coliform strains can be extremely toxic, and even fatal if consumed. Current technologies for coliform detection are expensive, require multiple complicated steps, and can take up to 24 hours to produce accurate results. Recently, open-channel, paper-based microfluidic devices have become popular for rapid, inexpensive, and accurate bioassays. In this work, we have created an integrated microfluidic coliform lysis and detection device by fabricating customizable omniphilic regions via direct printing of omniphilic channels on an omniphobic, fluorinated paper. This paper-based device is the first of its kind to demonstrate successful cell lysing on-chip, as it can allow for the flow and control of both high and low surface tension liquids, including different cell lysing agents. The fabricated microfluidic device was able to successfully detect E. coli, via the presence of the coliform-specific enzyme, β-galactosidase, at a concentration as low as ∼104 CFU mL-1. Further, E. coli at an initial concentration of 1 CFU mL-1 could be detected after only 6 hours of incubation. We believe that these devices can be readily utilized for real world E. coli contamination detection in multiple applications, including food and water safety.

Smooth, All-Solid, Low-Hysteresis, Omniphobic Surfaces with Enhanced Mechanical Durability

The utility of omniphobic surfaces stems from their ability to repel a multitude of liquids, possessing a broad range of surface tensions and polarities, by causing them to bead up and either roll or slide off. These surfaces may be self-cleaning, corrosion-resistant, heat-transfer enhancing, stain-resistant or resistant to mineral- or biofouling. The majority of reported omniphobic surfaces use texture, lubricants, and/or grafted monolayers to engender these repellent properties. Unfortunately, these approaches often produce surfaces with deficiencies in long-term stability, durability, scalability, or applicability to a wide range of substrates. To overcome these limitations, we have fabricated an all-solid, substrate-independent, smooth, omniphobic coating composed of a fluorinated polyurethane and fluorodecyl polyhedral oligomeric silsesquioxane. Liquids of varying surface tension, including water, hexadecane, ethanol, and silicone oil, exhibit low-contact-angle hysteresis (<15°) on these surfaces, allowing liquid droplets to slide off, leaving no residue. Moreover, we demonstrate that these robust surfaces retained their repellent properties more effectively than textured or lubricated omniphobic surfaces after being subjected to mechanical abrasion.

Association of established hypothyroidism-associated genetic variants with Hashimoto's thyroiditis

PURPOSE

Hashimoto's thyroiditis (HT) as a chronic autoimmune disease of the thyroid gland is the most common cause of hypothyroidism. Since HT and hypothyroidism are closely related, the main aim of this study was to explore the association of established hypothyroidism single-nucleotide polymorphisms (SNPs) with HT.

METHODS

The case-control dataset included 200 HT cases and 304 controls. Diagnosis of HT cases was based on clinical examination, measurement of thyroid antibodies (TgAb, TPOAb), hormones (TSH and FT4) and ultrasound examination. We genotyped and analysed 11 known hypothyroidism-associated genetic variants. Case-control association analysis was performed in order to test each SNP for the association with HT using logistic regression model. Additionally, each SNP was tested for the association with thyroid-related quantitative traits (TPOAb levels, TgAb levels and thyroid volume) in HT cases only using linear regression.

RESULTS

We identified two genetic variants nominally associated with HT rs3184504 in SH2B3 gene (P = 0.0135, OR = 0.74, 95% CI = 0.57-0.95) and rs4704397 in PDE8B gene (P = 0.0383, OR = 1.32, 95% CI = 1.01-1.74). The SH2B3 genetic variant also showed nominal association with TPOAb levels (P = 0.0163, β = -0.46) and rs4979402 inside DFNB31 gene was nominally associated with TgAb levels (P = 0.0443, β = 0.41).

CONCLUSIONS

SH2B3 gene has previously been associated with susceptibility to several autoimmune diseases, whereas PDE8B has been associated with TSH levels and suggested to modulate thyroid physiology that may influence the manifestation of thyroid disease. Identified loci are novel and biologically plausible candidates for HT development and represent good basis for further exploration of HT susceptibility.

Biochemical markers in vascular cognitive impairment associated with subcortical small vessel disease - A consensus report

Background

Vascular cognitive impairment (VCI) is a heterogeneous entity with multiple aetiologies, all linked to underlying vascular disease. Among these, VCI related to subcortical small vessel disease (SSVD) is emerging as a major homogeneous subtype. Its progressive course raises the need for biomarker identification and/or development for adequate therapeutic interventions to be tested. In order to shed light in the current status on biochemical markers for VCI-SSVD, experts in field reviewed the recent evidence and literature data.

Method

The group conducted a comprehensive search on Medline, PubMed and Embase databases for studies published until 15.01.2017. The proposal on current status of biochemical markers in VCI-SSVD was reviewed by all co-authors and the draft was repeatedly circulated and discussed before it was finalized.

Results

This review identifies a large number of biochemical markers derived from CSF and blood. There is a considerable overlap of VCI-SSVD clinical symptoms with those of Alzheimer’s disease (AD). Although most of the published studies are small and their findings remain to be replicated in larger cohorts, several biomarkers have shown promise in separating VCI-SSVD from AD. These promising biomarkers are closely linked to underlying SSVD pathophysiology, namely disruption of blood-CSF and blood–brain barriers (BCB-BBB) and breakdown of white matter myelinated fibres and extracellular matrix, as well as blood and brain inflammation. The leading biomarker candidates are: elevated CSF/blood albumin ratio, which reflects BCB/BBB disruption; altered CSF matrix metalloproteinases, reflecting extracellular matrix breakdown; CSF neurofilment as a marker of axonal damage, and possibly blood inflammatory cytokines and adhesion molecules. The suggested SSVD biomarker deviations contrasts the characteristic CSF profile in AD, i.e. depletion of amyloid beta peptide and increased phosphorylated and total tau.

Conclusions

Combining SSVD and AD biomarkers may provide a powerful tool to identify with greater precision appropriate patients for clinical trials of more homogeneous dementia populations. Thereby, biomarkers might promote therapeutic progress not only in VCI-SSVD, but also in AD.

Open-channel, water-in-oil emulsification in paper-based microfluidic devices

Open-channel microfluidic devices have shown great potential in achieving a high degree of fluid control, at relatively low-cost, while enabling the opportunity for rapid fabrication. However, thus far, work in open channel microfluidics has largely focused on controlling the flow of water or other aqueous solutions. In this work we present new open channel microfluidic devices based on surfaces with patterned wettabilty that are capable of controlling the flow of virtually all high and low surface tension liquids. The fabricated open channel devices are capable of constraining a variety of low surface tension oils at high enough flow rates to enable, for the first time, water-in-oil microfluidic emulsification in an open channel device. By changing the flow rates for both the aqueous (dispersed) and organic (continuous) phases, we show that it is possible to vary the size of the emulsified droplets produced in the open channel device. Finally, we utilized the fabricated devices to synthesize relatively monodisperse, hydrogel microparticles that could incorporate a drug molecule. We also investigated the drug release characteristics of the fabricated particles.

Designing Self-Healing Superhydrophobic Surfaces with Exceptional Mechanical Durability

The past decade saw a drastic increase in the understanding and applications of superhydrophobic surfaces (SHSs). Water beads up and effortlessly rolls off a SHS due to its combination of low surface energy and texture. Whether being used for drag reduction, stain repellency, self-cleaning, fog harvesting, or heat transfer applications (to name a few), the durability of a SHS is critically important. Although a handful of purportedly durable SHSs have been reported, there are still no criteria available for systematically designing a durable SHS. In the first part of this work, we discuss two new design parameters that can be used to develop mechanically durable SHSs via the spray coating of different binders and fillers. These parameters aid in the rational selection of material components and allow one to predict the capillary resistance to wetting of any SHS from a simple topographical analysis. We show that not all combinations of sprayable components generate SHSs, and mechanically durable components do not necessarily generate mechanically durable SHSs. Moreover, even the most durable SHSs can eventually become damaged. In the second part, utilizing our new parameters, we design and fabricate physically and chemically self-healing SHSs. The most promising surface is fabricated from a fluorinated polyurethane elastomer (FPU) and the extremely hydrophobic small molecule 1H,1H,2H,2H-heptadecafluorodecyl polyhedral oligomeric silsesquioxane (F-POSS). A sprayed FPU/F-POSS surface can recover its superhydrophobicity even after being abraded, scratched, burned, plasma-cleaned, flattened, sonicated, and chemically attacked.

Rational Design of Hyperbranched Nanowire Systems for Tunable Superomniphobic Surfaces Enabled by Atomic Layer Deposition

Superomniphobic surfaces display contact angles of θ* > 150° and low contact angle hysteresis with virtually all high and low surface tension liquids. The introduction of hierarchical scales of texture can increase the contact angles and decrease the contact angle hysteresis of superomniphobic surfaces by reducing the solid-liquid contact area. Thus far, it has not been possible to fabricate superomniphobic surfaces with three or more hierarchical scales of texture where the size, spacing, and angular orientation of features within each scale of texture can be independently varied and controlled. Here, we report a method for tunable control of geometry in hyperbranched ZnO nanowire (NW) structures, which in turn enables the rational design and fabrication of superomniphobic surfaces. Branched NWs with tunable density and orientation were grown via a sequential hydrothermal process, in which atomic layer deposition was used for NW seeding, disruption of epitaxy, and selective blocking of NW nucleation. This approach allows for the rational design and optimization of three-level hierarchical structures, in which the geometric parameters of each level of hierarchy can be individually controlled. We demonstrate the coupled relationships between geometry and contact angles for a variety of liquids, which is supported by mathematical models. The highest performing superomniphobic surface was designed with three levels of hierarchy and achieved the following advancing/receding contact angles with water 172°/170°, hexadecane 166°/156°, octane 162°/145°, and heptane 160°/130°.

Obesity dilemma in the global burden of cardiovascular diseases

AIM

Obesity is a well-known risk factor in the cardiovascular disease continuum. However, its clinical effects are multimodal, perplexed and non-unanimously understood. Our aim was to assess the prevalence and effects of obesity on the cardiometabolic risk factors and systolic function of left ventricle ejection fraction (LVEF) in patients scheduled for cardiovascular rehabilitation.

METHODS

A cohort of 302 consecutive patients recently treated for ischaemic or valvular heart disease was matched according to the existence of obesity, defined with body mass index (BMI ≥ 30 kg/m(2) ; n = 90 vs. 212), and the advanced grade of obesity (BMI ≥ 35 kg/m(2) ; n = 19 vs. 283). Nutritional risk screening was performed using the standardised NRS-2002 tool.

RESULTS

The mean age of patients was 62.4 ± 11.2 (range 23-86) years; there were more men than women 244 (80.8%) : 58 (19.2%). Group of obese conveyed higher prevalence of ischaemic heart disease than non-obese (OR = 2.69; 95% CI: 1.01-7.20; p = 0.048); while the difference was insignificant for the advanced grade of obesity (n = 17; 89.5%) vs. controls (n = 233; 82.3%; p > 0.05). There was no significant difference in prevalence of other comorbidities (diabetes, glucose intolerance, hypercholesterolaemia, chronic renal and chronic obstructive pulmonary disease) between studied groups (p > 0.05). Utilisation of lipid-lowering drugs was of similar range between the studied groups (p > 0.05), respectively. LVEF (%) was 50.5 ± 8.2 vs. 50.7 ± 7.7 (p > 0.05) and 50.6 ± 7.8 vs. 49.6 ± 10.9 (p > 0.05; Rho = 0.001; p > 0.05), respectively.

CONCLUSION

In studied set of patients, BMI positively correlated with left ventricle dimension and thickness. No significant connection of obesity was found with the prevalence of chronic comorbidities, increased nutritional risk, laboratory diagnostics or systolic function of left ventricle. Existence of obesity paradox in clinical practice was in part reaffirmed with our study.

Heart surgery stems increased nutritional risk, expressed during the course of stationary rehabilitation

BACKGROUND

Cardiovascular diseases are a vast global health burden. Despite common prevalence, current knowledge and investigations concerning nutritional aspects are limited. Characteristics and dynamics of nutritional risk are not entirely known for most of the entities, disease stages or treatment-induced fluctuations. This study assessed the effects of heart surgery on unintentional weight loss and nutritional risk using the NRS-2002.

METHODS

A noninterventional study that included patients scheduled for rehabilitation 1-6 months after heart surgery was performed. Evaluation included routine cardiovascular diagnostics and review of medical histories. Documented baseline weight was available for >85% of the patients. Nutritional risk screening was performed with the standardized NRS-2002 questionnaire.

RESULTS

A total of 145 patients were involved, with a mean age of 65.3 ± 11.5 years in a range of 23-84 years. The male to female ratio was 121:24 (83.4%:16.6%), respectively. Coronary artery bypass graft surgery (CABG) was performed in 89 patients (61.4%), valvular surgery (VS) in 34 (23.4%) and combined operations (CABG + VS) in 22 (15.2%). Percentage weight loss history was 11.1 ± 3.4% in a range of 0-20.1%, while NRS-2002 was 4.77 ± 1.05 in a range of 1-6. Increased nutritional risk (NRS-2002 ≥3) was found in nearly all patients. Combined ischemic and valvular etiology displayed the highest values of NRS-2002 (5.0 ± 1.2). Patient age and creatinine showed significant correlations with NRS-2002 (Rho = 0.521, p < 0.001 and Rho = 0.335, p < 0.001, respectively).

CONCLUSION

Increased nutritional risk was found to be frequently prevalent in patients scheduled for rehabilitation after heart surgery. Risk was found to be in relation with underlying coronary artery disease as well as with the age of patients and parameters of renal function. Routine application of nutritional risk screening appears to be a valuable clinical tool for detecting this relevant comorbidity, particularly since no connection was found with traditional anthropometrics.

Combination of capecitabine and mitomycin C as first-line treatment in patients with metastatic breast cancer

Optimal first-line chemotherapy for metastatic breast cancer (MBC) is challenging, particularly in patients previously treated with (neo) adjuvant anthracyclines/taxanes. Based on preclinical synergy with mitomycin C (MMC) and capecitabine in human tumor xenografts, we conducted a phase II study of first-line capecitabine and MMC in MBC. Patients received 3-weekly chemotherapy comprising MMC 8 mg/m² day 1 and capecitabine 1000 mg/m² twice daily, days 1-14. Combination chemotherapy was administered for a maximum six cycles, single-agent capecitabine could be continued until progressive disease or unacceptable toxicity. Thirty patients were included, objective response rate was 65.5%. After a median follow-up of 18.5 months, median time to progression was 8.5 months and median overall survival was 29.8 months. The main adverse events were thrombocytopenia, pneumonitis and hemolytic uremic syndrome. Our data suggest that first-line capecitabine and MMC has good antitumor activity in MBC, but is associated with MMC-specific toxicity.

Lapatinib in the treatment of HER-2 overexpressing breast cancer

Lapatinib is the only clinically available agent for the treatment of patients with human epidermal growth factor receptor-2 (HER-2) positive tumors that have progressed on treatment with trastuzumab, taxanes and anthracyclines. Moreover, when given with letrozole in postmenopausal patients with estrogen receptor (ER) and HER-2 positive disease it induces clinically meaningful benefit. Recently presented neoadjuvant data suggests an important place for the combination of trastuzumab and lapatinib in the therapy of early HER-2 positive breast cancer. This article reviews the current status and future perspectives of lapatinib.

Cardiovascular effects in vitro of aqueous extract of wild strawberry (Fragaria vesca, L.) leaves

In contrast to the strawberry fruits, strawberry leaves as a source of bioactive compounds with potentially beneficial biological effects have been largely overlooked. In this study we examined direct, dose-dependent effects of wild strawberry (Fragaria vesca, L.) leaves aqueous extract, in two experimental models and animal species, the isolated guinea pig hearts and rat aortic rings. Vasodilatory potential of the wild strawberry leaves extract was compared with vasodilatory activity of aqueous extract of hawthorn (Crataegus oxycantha, L) leaves with flowers, which can be regarded as a reference plant extract with a marked vasodilatory activity. The extracts were analysed by their "phenolic fingerprints", total phenolic content and antioxidative capacity. Their vasodilatory activity was determined and compared in the isolated aortic rings from 24 rats that were exposed to the extracts doses of 0.06, 0.6, 6, and 60 mg/100ml. Both extracts induced similar, dose-dependent vasodilation. Maximal relaxation was 72.2+/-4.4% and 81.3+/-4.5%, induced by the strawberry and hawthorn extract, respectively. To determine vasodilatory mechanisms of the wild strawberry leaves extract, endothelium-denuded and intact rings exposed to nitric oxide (NO) synthase inhibitor L-NAME or cyclooxygenase inhibitor indomethacin were used. Removal of the endothelium prevented and exposure to L-NAME or indomethacin strongly diminished the vasodilatatory response to the extract. In the isolated hearts (n=12), the wild strawberry extract was applied at concentrations of 0.06, 0.18, 0.6, and 1.8 mg/100ml. Each dose was perfused for 3.5 min with 15 min of washout periods. Heart contractility, electrophysiological activity, coronary flow and oxygen consumption were continuously monitored. The extract did not significantly affect heart rate and contractility, main parameters of the cardiac action that determine oxygen demands, while coronary flow increased up to 45% over control value with a simultaneous decrease of oxygen extraction by 34%. The results indicate that the aqueous extract of wild strawberry leaves is a direct, endothelium-dependent vasodilator, action of which is mediated by NO and cyclooxygenase products and which potency is similar to that of the hawthorn aqueous extract.

Capecitabine and mitomycin-C in the therapy of pretreated patients with metastatic colorectal cancer: single center retrospective study with 36 patients

PURPOSE

To evaluate the therapeutic effectiveness and safety of treatment with capecitabine and mitomycin-C (MMC) in patients with metastatic colorectal cancer previously treated with at least one chemotherapy regimen for recurrent or metastatic disease.

PATIENTS AND METHODS

A total of 36 patients (male/female 21/15, median age 62.5 years) with metastatic colorectal cancer were treated with capecitabine and MMC as their second, third or fourth line chemotherapy regimen. Chemotherapy consisted of intravenous MMC 6 mg/m(2) on day 1 plus oral capecitabine 1000 mg/m(2) twice daily on days 1-15 followed by 7-day rest. Treatment courses were repeated every 3 weeks unless there was evidence of progressive disease or unacceptable toxicity.

RESULTS

All 36 patients were evaluable for toxicity and response. A total of 175 cycles were administered (median 4.86, range 3-6). Two (5.6%) patients achieved complete response, 3 (8.3%) partial response, 14 (38.9%) had stable disease and 16 (44.4%) patients progressed. Median time to tumor progression (TTP) was 4.5 months and median overall survival (OS) 13 months. No toxic deaths occurred. Toxicity was mild and easily manageable.

CONCLUSION

This retrospective study demonstrated that the combination of capecitabine and MMC is an effective and well-tolerated regimen for patients previously treated for metastatic or recurrent colorectal cancer.

Dose dependent effects of standardized nose-horned viper (Vipera ammodytes ammodytes) venom on parameters of cardiac function in isolated rat heart

Direct, dose dependent effects of the nose-horned vipers (Vipera ammodytes ammodytes) venom on various parameters of cardiac action in isolated rat hearts were examined. Biochemical (protein content, SDS polyacrylamide gel electrophoresis) and biological (minimum haemorrhagic and necrotizing dose and lethal dose (LD(50))) characterization of the venom was performed before testing. The hearts were infused with venom doses of 30, 90 and 150 microg/mL for 10 min followed by 30 min of wash out period. Left ventricular pressure, coronary flow, heart rate, atrioventricular conduction, myocardial oxygen consumption, incidence and duration of arrhythmias were measured and relative cardiac efficiency was calculated. Cardiac CPK, LDH, AST and troponin I were measured as biochemical markers of myocardial damage. The venom caused dose dependent electrophysiological instability and depression of contractility and coronary flow. Effects on the heart rate were biphasic; transient increase followed by significant slowing of the frequency. Relative cardiac efficiency decreased as oxygen consumption remained high relative to the heart rate-contractility product, indicating purposeless expenditure of oxygen and energy. Effects by the dose of 30 microg/mL were highly reversible while the dose of 90 mug/mL caused damages that were mostly irreversible. The dose of 150 mug/mL induced irreversible asystolic cardiac arrest.

Analysis of antiepileptic drugs use at a university hospital in Croatia

To analyse the consumption rate of new generation antiepileptic drugs (AEDs) compared with traditional AEDs at a university hospital in Croatia. Antiepileptic drugs use was analysed retrospectively for two consecutive years, 2001 and 2002 at Departments of Neurology, Paediatrics, Psychiatry and Neurosurgery at the University Hospital Centre (UHC) Rijeka. The results obtained are expressed as number of defined daily doses (DDDs) per 100 bed days, as proposed by the WHO. The use of new generation AEDs was represented by 2% in 2001 and 5% in 2002. Majority of AEDs administered was taken by the barbiturates in both years. A wide spectrum of AEDs has been used at the Department of Paediatrics. At the Department of Neurology and Psychiatry use of barbiturates and carbamazepine predominated. The use of new AEDs at UHC has increased during the investigation period but it is still rather low compared with traditional AEDs. The similarity of our results with the result of the leading Croatian university hospitals might represent general routine AED prescription in country. Nationally based guidelines may bring more appropriate and rational approach for usage of modern AED. This task should be supported and promoted by international and national neurology associations.

Gender differences in antioxidant capacity of rat tissues determined by 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate; ABTS) and ferric reducing antioxidant power (FRAP) assays

Differences in susceptibility to oxidative stress between males and females have been postulated. Several methods have been developed to assess the total antioxidant capacity of human serum or plasma, but just recently some of them were employed for measurement of antioxidant capacity of tissues. In this study, we measured and compared antioxidant capacity of heart, kidney, liver and brain tissues of male and female rats. Antioxidant capacity was determined using 2,2'-azinobis (3-ethylbenzothiazoline 6-sulfonate; ABTS) and ferric reducing antioxidant power (FRAP) assays. In the same samples, lipid peroxidation products of these tissues were analysed using thiobarbituric acid reactive substances (TBARS) assays. Antioxidant capacity of heart, kidney and liver tissues was higher in female than male rats for both FRAP and ABTS assays. We found positive correlation between FRAP and ABTS values for all tested tissues. FRAP and ABTS proved to be comparable, simple and quick methods for antioxidant capacity scanning in tissues. TBARS levels differed only for brain tissue, being higher in males. These results indicate stronger defense against oxidative damage in females for all observed tissues. These finding may account for the longer lifespan of females.

Blood gases and sex hormones in women with and without genital descensus

BACKGROUND

Abnormalities in connective tissue and spirometric disorders have previously been found in women with genital descensus.

OBJECTIVE

To evaluate the association of descensus and respiratory function.

METHODS

The blood gases and sex hormones were measured in 130 women scheduled for surgical correction of descensus and 60 matched women without descensus. All subjects were nonsmokers and without past or present cardiorespiratory disease.

RESULTS

Women with descensus had a lower pH (7.39+/-0.04 vs. 7.41+/-0.04, p = 0.01), lower arterial tensions of oxygen (12.7+/-12. vs. 14.1+/-0.9 kPa, p = 0.003) and carbon dioxide (5.1+/-0.4 vs. 5.3+/-0.3 kPa) but a higher hemoglobin concentration (141+/-11 vs. 132+/-9 g/l) and a higher serum progesterone in the follicular phase of the cycle (3.1+/-4 vs. 1.5+/-1 ng/ml, p = 0.03). In 39 (30%) women with descensus, the arterial carbon dioxide tension was below 4.9 kPa. All subjects ventilated more in the luteal compared to the follicular phase of the cycle. In women with descensus, the hemoglobin concentration increased with decreasing arterial oxygen tension (p = 10(-4)) and with decreasing pH (p<10(-3)).

CONCLUSION

Women with descensus frequently hyperventilate and, compared with women without descensus, have a lower arterial oxygen tension, increased hemoglobin concentration and slightly lower pH.

Effects of L-arginine and N omega-nitro-L-arginine methyl ester on cardiac perfusion and function after 1-day cold preservation of isolated hearts

BACKGROUND

Coronary flow responses to endothelium-dependent (acetylcholine [ACh] or 5-hydroxytryptamine [5-HT]) and endothelium-independent (adenosine [ADE] or nitroprusside [NP]) vasodilators may be altered before and after 1-day hypothermia during the perfusion of arginine vasopressin (AVP), D-arginine (D-ARG), L-arginine (L-ARG), or nitro-L-arginine methyl ester (L-NAME).

METHODS AND RESULTS

Four groups of guinea pig hearts (37.5 degrees C [warm]) were perfused for 6 hours with AVP, L-ARG, L-NAME, or nothing (control). Five heart groups (cold) were perfused with AVP, D-ARG, L-ARG, L-NAME, or nothing (control), but after 2 hours they were perfused at low flow for 22 hours at 3.7 degrees C and again for 3 hours at 37.5 degrees C. ADE, butanedione monoxime, and NP were given for cardioprotection before, during, and after hypothermia. In warm groups, L-ARG did not alter basal flow or ADE, ACh, 5-HT, or NP responses, whereas L-NAME and AVP reduced basal flow and the ADE response, abolished ACh and 5-HT responses, and increased the NP response. In cold groups after hypothermia. L-ARG did not alter basal flow, but L-NAME, AVP, D-ARG, and control reduced flow. In the postcold L-ARG group, ACh increased peak flow, but NP did not increase flow in other cold groups. Effluent L-ARG and L-CIT in the cold control group fell from 64 +/- 9 and 9 +/- 1 micrograms/L at 1 hour to 36 +/- 5 and 5 +/- 1 micrograms/L at 25 hours, respectively. Left ventricular pressure and cardiac efficiency improved more in the postcold L-ARG group than in the postcold D-ARG, AVP, and L-NAME groups.

CONCLUSIONS

Endogenous effluent levels of L-ARG and L-CIT decrease after 24 hours in isolated hearts, whereas perfusion of L-ARG improves cardiac performance, basal coronary flow, and vasodilator responses. In contrast, L-NAME, L-ARG, and AVP limit flow and performance but maintain a partial vasodilatory response to NP. Sustained release of NO may account for improved performance after L-ARG after hypothermia.

Muscarinic and ganglionic blocking properties of atropine compounds in vivo and in vitro: time dependence and heart rate effects

High doses (3 mg/kg) of methylatropine nitrate have been used in vivo to produce long-lasting muscarinic blockade during physiologic experiments. At these levels, the possibility exists that ganglionic blockade may also be responsible for some heart rate effects. Therefore, the effects of methylatropine nitrate (0.0012-2.4 mg.kg(-1)) and atropine sulfate (0.0036 - 0.060 mg.kg(1)) were evaluated in vivo using conscious dogs and in vitro using canine right atria and isolated stellate ganglia. The lowest doses of either agent given in vivo caused bradycardia, while intermediate doses induced excess tachycardia. High doses of methylatropine nitrate transiently decreased the heart rate, followed by slow recovery. In vitro using the canine right atria, neither drug caused pacemaker shifts nor directly altered the atrial rate, but postvagal tachycardia occurred with acetylcholine challenge and was prevented by metoprolol or 6-hydroxydopamine. In vitro studies using the canine stellate ganglia indicate that both agents depressed postganglionic compound action potentials at high doses. In conclusion, with high-dose methylatropine nitrate, ganglionic blockade yields the mechanism for a reduction of excess tachycardia as well as a likely explanation for opposing chronotropic effects in conscious and anesthetized dogs. In experimental studies where high doses of atropine compounds are used for long-term muscarinic blockade, it is possible that ganglionic blocking effects may also be produced.

Direct comparative effects of isoflurane and desflurane on sympathetic ganglionic transmission

Although the sympathetic ganglion is an important site of peripheral regulation, few studies have examined the effect of anesthetics on synaptic transmission. In the present study we compared the actions of desflurane with those of isoflurane on synaptic transmission and neurotransmitter release in the stellate ganglion. In the electrophysiologic group, 14 stellate ganglia were isolated from adult mongrel dogs after halothane anesthesia, desheathed, and superfused with Krebs' solution. Compound action potentials (CAP) were induced by supramaximal stimulation of the preganglionic T3-ramus at a low frequency of 0.4 Hz and were recorded from the postganglionic ventral ansa subclaviae. Each ganglion was exposed to two levels of anesthetics (equivalent to 1 and 2 minimum alveolar anesthetic concentration [MAC]), followed by an anesthetic-free washout period. While equianesthetic concentrations of isoflurane and desflurane caused essentially equipotent suppression of ganglionic transmission, desflurane was more efficacious than isoflurane, both with respect to the onset of and recovery from the inhibition of synaptic activity. In the electrochemical group, 25 ganglia were exposed to both anesthetics at a high concentration (equivalent to between 1.82 and 1.95 MAC) during maximal and submaximal current stimulations, and the release of actylcholine (ACh) in the superfusate was measured with liquid chromatography. Although desflurane and isoflurane caused a significant depression of CAP, neither anesthetic inhibited the release of ACh in the superfusate at either maximal or submaximal current stimulations. These results indicate that the suppression of ganglionic activity is equipotent for both anesthetics based on equivalent MAC values, but that desflurane is more efficacious than isoflurane with respect to onset and recovery at the higher concentrations of anesthetics.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of stereospecific effects of isoflurane and desflurane isomers in isolated guinea pig hearts

BACKGROUND

Volatile anesthetics alter membrane channel proteins. It is controversial whether they act by nonspecifically perturbing lipid membranes or by directly binding to amphiphilic and usually stereoselective regions on channel macromolecules. Biologically relevant receptors are usually stereoselective. The stereochemical effect of isoflurane and desflurane can be used as a pharmacologic tool to investigate whether these drugs bind to specific target sites. The specific optical isomers of isoflurane and desflurane were used to examine whether they produce any differential effects on electrical, mechanical, and metabolic function in isolated hearts.

METHODS

Isolated guinea-pig hearts were perfused with Krebs-Ringer's solution containing, in random order, both isomers of either isoflurane (n = 11) or desflurane (n = 6) for 10 min with a 15-min washout period. Either anesthetic was injected into a preoxygenated, sealed bottle of perfusate, which gave concentrations of 0.28 and 0.57 mM for isoflurane and 0.48 and 0.88 mM for desflurane, which are equivalent to 1 and 2 MAC multiples.

RESULTS

Both isomers of isoflurane and desflurane decreased left ventricular pressure, heart rate, and percent oxygen extraction and increased atrioventricular conduction time, coronary flow, and oxygen delivery. Each change was significantly different from control at each concentration, and these effects were greater with the high compared to the low concentration of each anesthetic. There was no significant difference between the (+)- and the (-)-isomers for either anesthetic for any measured or calculated variable. Also, the effects of the stereoisomers were similar to those of the racemic mixture.

CONCLUSIONS

These data indicate that the optical isomers of isoflurane and desflurane are equipotent, as assessed by their effects on cardiac function in isolated guinea-pig hearts. Although both agents may ultimately influence hydrophilic domains of the protein channels, their major cardiac effect appears to result either from global perturbation of the membrane lipids and/or an interaction at nonstereoselective sites on channels modulating cardiac anesthetic effects.

Contraction uncoupling with butanedione monoxime versus low calcium or high potassium solutions on flow and contractile function of isolated hearts after prolonged hypothermic perfusion

BACKGROUND

Normal ionic perfusate containing butanedione monoxime (BDM), a reversible myofilament inhibitor, could be better than either a high potassium (KCl) or a low calcium (CaCl2) perfusate for long-term cardiac preservation. This hypothesis was tested in 70 isolated guinea pig hearts.

METHODS AND RESULTS

Three groups--time control (8 hours, 37 degrees C), cold control (22 hours, 3.8 degrees C), and cold+BDM (22 hours)--were perfused with typical Krebs-Ringer solution (2.5 mmol/L CaCl2 and 4.5 mmol/L KCl). Two other groups were cold perfused for 22 hours either with 2.5 mmol/L CaCl2 + 20 mmol/L KCl (high) or with 0.5 mmol/L CaCl2 (low) + 4.5 mmol/L KCl. These changes were maintained from 20 minutes before cold perfusion until 30 minutes after rewarming to 37 degrees C. Coronary vasodilator reserve was tested before cold perfusion and 2 hours after warm reperfusion with adenosine (Ade), acetylcholine (Ach, endothelium dependent), and nitroprusside (NP, endothelium independent). Each treatment decreased left ventricular pressure (LVP) by more than 80% before cold perfusion. During warm reperfusion, LVP was lower in cold control (-72 +/- 5%), high KCl (-76 +/- 4%), and low CaCl2 (-80 +/- 4%) groups than in BDM (-38 +/- 3%) or time control (-18 +/- 4%) groups; coronary flow (CF) was lower in high KCl (-67 +/- 4%) and low CaCl2 (-54 +/- 7%) groups than in cold control (-37 +/- 6%), BDM (-30 +/- 5%), or time control (+2 +/- 3%) groups; and percent oxygen extraction (controls, 62 +/- 4%) was higher in the high KCl group (83 +/- 6%) than in cold control (72 +/- 3%), BDM (73 +/- 3%), low CaCl2 (72 +/- 5%), or time control (63 +/- 3%) groups. CF responses to Ade, Ach, and NP (+103 +/- 7%, +24 +/- 5%, and +34 +/- 5% before cold) were attenuated (+76 +/- 6%, +18 +/- 5%, and +23 +/- 4%) in the time control group (5 hours later), were reduced but present in the BDM group (+10 +/- 5%, -5 +/- 5%, and -5 +/- 5%), and were absent in both low CaCl2 and high KCl groups after 2 hours of reperfusion.

CONCLUSIONS

Normal ionic BDM solution better preserves cardiac function and basal CF after prolonged cold perfusion than do cold control, high KCl, and low CaCl2 solutions. Vasodilatory capacity is markedly diminished after perfusion with either the high KCl or the low CaCl2 solution.

Anesthetics and automaticity in latent pacemaker fibers. IV. Effects of isoflurane and epinephrine or norepinephrine on automaticity of dominant and subsidiary atrial pacemakers in the canine heart

BACKGROUND

Anesthesia and surgery may be associated with atrioventricular junctional or ventricular rhythm disturbances. These may be caused by alteration of automaticity of primary and subsidiary pacemakers.

METHODS

The direct effects of isoflurane, alone or in combination with epinephrine (E) and norepinephrine (NE), as well as single effects of E and NE, were examined on automaticity of primary and subsidiary atrial pacemakers (SAP) using a perfused canine right atrial preparation (n = 29). Preparations were perfused with oxygenated Krebs' solution at a constant perfusion pressure of 87 mmHg and a temperature of 36.5 +/- 0.5 degrees C. Delivered concentrations of isoflurane of 1.4 and 2.8% corresponded to measured perfusate concentrations of 315 +/- 7 and 617 +/- 16 microM in experiments with E (n = 14), and 316 +/- 10 and 610 +/- 26 microM in experiments with NE (n = 15). Epinephrine or NE perfusate concentrations were 2 and 5 micrograms/l or 5 and 10 micrograms/l, respectively. To determine the site of earliest activation, extracellular recordings were made from the SA node region and distal sites (approximately 1, 2, and 3 cm) along the sulcus terminalis, the previously reported locations of SAP. Sites of earliest activation shifts from SA node to SAP were scored 1, 2, or 3 depending on the distance from the control pacemaker. The summed shift scores (magnitude score) were normalized by dividing by the total number of preparations for each experimental condition.

RESULTS

Exposure to isoflurane, NE, or E alone did not produce a significant increase in the incidence of pacemaker shifts or normalized pacemaker shift scores. Only the high dose of E significantly increased the incidence of pacemaker shifts and normalized shift scores. Dysrhythmogenic potential of E and NE tended to be greater after earlier exposure to isoflurane. Every combination of isoflurane with E or NE produced a significant increase in the incidence of pacemaker shifts and normalized shift scores.

CONCLUSIONS

It was concluded that isoflurane with E or NE acts synergistically to increase dysrhythmic potential in the arterial tissue.

Potassium channel openers attenuate atrioventricular block by bupivacaine in isolated hearts

Our purpose was to test if pinacidil and bimakalim (EMD 52692 or SR 44866), which are ATP-sensitive K+ (K+ATP) channel openers, can attenuate bupivacaine-induced atrioventricular (AV) block. Bupivacaine-induced AV block was studied in 24 isolated guinea pig hearts with or without either pinacidil or bimakalim. Hearts were perfused at 55 mm Hg with a modified Krebs' perfusate. Variables monitored were: heart rate, AV conduction time, left ventricular pressure, coronary flow, and myocardial oxygen extraction. Bupivacaine was infused at a constant concentration of 4 microM to induce first degree AV block and 15-25 microM to induce second degree heart block. During a stable AV block (e.g., first degree, 2:1, 3:2, or 4:3), K+ channel openers, pinacidil (up to 30 microM) or bimakalim (up to 2 microM) were added to perfusate containing bupivacaine. The effects of K+ channel openers were also examined in the presence of the selective K+ATP channel blocker, glibenclamide (2.2 microM). On the average, 4 microM bupivacaine prolonged AV conduction by 53%, and decreased heart rate by 13%, left ventricular pressure by 26%, coronary flow by 6%, and percent oxygen extraction by 7%. In the presence of bupivacaine, pinacidil and bimakalim additionally decreased left ventricular pressure and oxygen extraction, markedly increased coronary flow, and attenuated the prolongation of AV conduction by 20% with no further change in heart rate. The beneficial effect of bimakalim on AV block was reversed by glibenclamide. Second degree AV block produced by higher doses of bupivacaine was converted to first degree AV block by either pinacidil or bimakalim in 6 of 8 and 7 of 8 hearts, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Reperfusion with adenosine and nitroprusside improves preservation of isolated guinea pig hearts after 22 hours of cold perfusion with 2,3 butanedione monoxime

The function of isolated guinea pig hearts treated with 2,3 butanedione monoxime (BDM) before, during, and initially after 22 h of hypothermic perfusion was examined during 4 h of normothermic reperfusion. BDM is a vasodilatory and negative inotropic agent that reversibly decreases sensitivity of contractile proteins to Ca2+. Also examined were the effects of adenosine (ADE) and nitroprusside (NP) in improving coronary flow (CF) and contractile function when given with BDM during rewarming and during the initial period of normothermic reperfusion. Isovolumetric left ventricular pressure (LVP), CF, and percentage of O2 extraction (%O2E) were measured in Krebs-Ringer-perfused hearts divided into three groups of 11 hearts each: drug-free controls (0 BDM); 10 mM BDM alone; and 10 mM BDM + 10 microM ADE + 100 microM NP. BDM was given 20 min before hypothermia, during hypothermia (3.8 degrees +/- 0.1 degree C) for 22 h, and for 30 min after rewarming to 37 degrees +/- 0.1 degree C; ADE was given with NP for only 20 min before and during rewarming and for 30 min after rewarming. Hearts were perfused at low constant flow with oxygenated Krebs' solution during hypothermia. After 2.5-h normothermic reperfusion, LVP (initial controls 108 +/- 6 mm Hg) increased more with BDM + ADE + NP (80 +/- 4% of control) than with BDM alone (62 +/- 3%) or without BDM (28 +/- 5%). CF (controls 6.0 +/- 0.5 ml/g/min) decreased less with BDM + ADE + NP (77 +/- 4% of control) than with BDM alone (60 +/- 5%) or without BDM (53 +/- 6%).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of 2,3-butanedione monoxime in isolated hearts: protection during reperfusion after global ischemia

The cardiac effects of 2,3-butanedione monoxime on electrical and mechanical function, rhythm, oxygen utilization, and coronary flow responsiveness, particularly during severe ischemia and reperfusion, have not been studied. After perfusing hearts at 55 mm Hg, coronary perfusion was interrupted for 30 minutes and was then reestablished at the control perfusion pressure for 40 minutes. Hearts were divided into four groups (n = 10 each) treated with 0, 3, 5, or 10 mmol/L of 2,3-butanedione monoxime added to the perfusate for 10 minutes before and during ischemia and for the first 10 minutes of reperfusion. An additional nonischemic group served as a time control. Variables monitored were heart rate, atrioventricular conduction time, cardiac rhythm, isovolumetric systolic and diastolic left ventricular pressure, maximum rate of left ventricular pressure change, coronary flow, myocardial oxygen consumption, and the ratio of oxygen delivery to myocardial oxygen consumption. Before ischemia, 2,3-butanedione monoxime significantly decreased isovolumetric left ventricular systolic pressure and increased the ratio of oxygen delivery to myocardial oxygen consumption in a dose-dependent manner, with only slight changes in heart rate and atrioventricular time with 10 mmol/L of 2,3-butanedione, monoxime. After 40 minutes of reperfusion, isovolumetric left ventricular systolic pressure recovered to 81 +/- 5% and 83 +/- 2% of the initial control values for the 5 and 10 mmol/L 2,3-butanedione monoxime groups. This was significantly greater than the recovery for the 0 and 3 mmol/L 2,3-butanedione monoxime groups, 59 +/- 3% and 63 +/- 4%, respectively. Similarly, the duration of ventricular fibrillation and of tachycardia was significantly lower, coronary flow reserve was better preserved, and myocardial oxygen consumption was greater with reperfusion in the 5 and 10 mmol/L 2,3-butanedione monoxime groups than in the 0 mmol/L 2,3-butanedione monoxime group. This study shows that relatively low concentrations of 2,3-butanedione monoxime, given before global ischemia and early during reperfusion of isolated hearts, can protect against dysrhythmias and improve return of myocardial and vascular function.

Direct comparative effects of isoflurane and desflurane in isolated guinea pig hearts

The aim of this study was to test if myocardial and coronary vascular effects of desflurane and isoflurane were similar in the isolated heart. The cardiac effects of these anesthetics were examined in 12 guinea pig hearts perfused in a retrograde manner. Spontaneous heart rate, atrioventricular (AV) conduction time, systolic left ventricular pressure and coronary flow were measured. To differentiate direct vasodilatory effects of these anesthetics from an indirect metabolic effect due to autoregulation of coronary flow, O2 delivery (DO2), myocardial O2 consumption (MVO2) and percent O2 extraction were also monitored. Isoflurane and desflurane were injected directly into sealed bottles containing oxygenated perfusate solution. Each heart was perfused randomly with these anesthetics. Anesthetic concentrations in the perfusate were 0.28 +/- 0.02 and 0.52 +/- 0.02 mM for isoflurane and 0.59 +/- 0.01 and 1.02 +/- 0.09 mM for desflurane (mean +/- standard error of the mean). Calculated vapor concentrations were 1.3 and 2.5 vol % for isoflurane and 6.8 and 11.8 vol % for desflurane which correspond to approximately 1 and 2 MAC in vivo. Each anesthetic similarly decreased heart rate and prolonged AV conduction time in a concentration-dependent manner. Left ventricular pressure (control 93 +/- 4 mmHg) decreased by 11 +/- 1% and 24 +/- 2% with isoflurane and by 15 +/- 1% and 30 +/- 2% with desflurane. The decreases in heart rate and pressure were accompanied by decreases in MVO2 of 12 +/- 2% and 30 +/- 3% with isoflurane and of 19 +/- 3% and 40 +/- 4% with desflurane from a control of 57 +/- 2 microliters.g-1.min-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypersensitivity to P. officinalis pollen: correlation of IgE with skin testing methods

Fifty pollinosis patients, who have reported contact with P. officinalis, were tested for skin sensitivity with P. officinalis pollen extract. Intracutaneous testing and the skin prick method were employed and their sensitivity verified with regard to serum concentrations of specific IgE antibodies determined with the RAST method. Two criteria of the skin prick method evaluation were employed. The intracutaneous method correlated best with RAST. In contrast to intracutaneous testing, the skin prick method did not produce any false-positive results; however, due to a few false-negative cases observed, it appeared that in borderline-negative cases the skin prick method would require determination of serum IgE antibodies to reach a clear-cut diagnosis.

[Ketotifen and nasal steroids in the therapy of pollinosis]

Thirty-five patients with seasonal pollen rhinitis due to hypersensitivity to Parietaria officinalis pollen were randomized and treated with ketotifen and with a combination of ketotifen and beclomethason diproprionate, a nasal steroid. The study was timed to cover the Parietaria off. pollination period (4 months), which was documented by the determination of air concentration of the pollen. Respiratory symptoms and additional medications were scored according to a defined control. During the peak pollen period, both groups suffered from intensified pollinosis symptoms which prompted additional medication. The increases, however, were less significant in the group treated with the combination of the two drugs, i.e. better results were obtained with the ketotifen-beclomethasone diproprionate combination than with ketotifen alone.