Organ-specific model of simulated ischemia/reperfusion and hyperglycemia based on engineered heart tissue

Here we aimed to establish an in vitro engineered heart tissue (EHT) co-morbidity mimicking model of ischemia-reperfusion injury and diabetes. EHTs were generated from primary neonatal rat cardiomyocytes. Hyperglycemic conditions or hyperosmolar controls were applied for one day to model acute hyperglycemia and for seven days to model chronic hyperglycemia. 120 min' simulated ischemia (SI) was followed by 120 min' reperfusion (R) and 1-day follow-up reperfusion (FR). Normoxic controls (N) were not subjected to SI/R. Half of the EHTs was paced, the other half was left unpaced. To assess cell injury, lactate-dehydrogenase (LDH) concentration was measured. Beating force and activity (frequency) were monitored as cardiomyocyte functional parameters. LDH-release indicated relevant cell injury after SI/N in each experimental condition, with much higher effects in the chronically hyperglycemic/hyperosmolar groups. SI stopped beating of EHTs in each condition, which returned during reperfusion, with weaker recovery in chronic conditions than in acute conditions. Acutely treated EHTs showed small LDH-release and ∼80% recovery of force during reperfusion and follow-up, while chronically treated EHTs showed a marked LDH-release, only ∼30% recovery with reperfusion and complete loss of beating activity during 24 h follow-up reperfusion. We conclude that EHTs respond differently to SI/R injury in acute and chronic hyperglycemia/hyperosmolarity, and that our EHT model is a novel in vitro combination of diabetes and ischemia-reperfusion.

Responsiveness of the widely used cardiomyocyte cell platforms to simulated ischemia/reperfusion

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office of Hungary (NKFIA; NVKP-16-1-2016-0017 National Heart Program and OTKA-FK 134751)

MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary

Ischemic heart disease is the leading cause of death worldwide; therefore, the development of cardioprotective therapies is currently a main focus of research. Cultured cell lines and primary cell cultures play an integral role in cardiovascular research. However, there are many limitations when using these models, including variations in proliferation capacity, uncontrolled stress during cell isolation, poor reproducibility and low translational value. The aim of our study was to test the responsiveness of the most widely used cardiomyocyte platforms to simulated ischemia/reperfusion injury (SI/R) considering the effect of differentiation protocols.

Human, rat and mouse cell lines as well as primary cell cultures were used for in vitro viability assay with or without widely used differentiation protocols. The cells were exposed to normoxic or simulated ischemia/reperfusion protocols: a simulated ischemic period of 6 hours was used for the primary and the differentiated cell cultures, while for the non-differentiated cells 16 hours of simulated ischemia followed by 2 hours of reperfusion was applied. The duration of simulated ischemia was determined from preliminary experiments. Viability of the cells was measured by calcein assay.

In non-differentiated human AC16 and rat H9C2 cardiac cell lines, cell viability was significantly reduced (50%) by 16h SI / 2h R in contrast, the viability of the mouse HL-1 cell line was not reduced by 16 h SI. In primary rat neonatal cardiac myocytes 6h SI / 2h R caused significant cell death (25%). In primary human iPSC-derived cardiac myocytes 6h SI / 2h R did not result significant injury (10%) whereas 16h did (37%). Responsiveness of different cell types to SI/R ranged between 40-100%.

We have shown that the responsiveness of primary cardiac cells and non-differentiated cardiac cell lines is significantly different to simulated ischemia / reperfusion. Differentiation protocols in cell lines markedly affects their response to simulated ischemia / reperfusion. Comparative analyses of different types of cardiomyocytes can provide a good basis for accurate design of in vitro cardioprotective test systems.

Identification of cardioprotective miRNAs (protectomiRs) in a porcine model of acute myocardial infarction and cardioprotection by ischemic conditioning

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office of Hungary (NKFIA; NVKP-16-1-2016-0017 National Heart Program and OTKA-FK 134751)

MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary

Introduction

Changes in the expression profile of microRNAs contribute to cardioprotective signaling. We have previously identified cardioprotective microRNAs, termed protectomiRs, by a systematic analysis of microRNA expression pattern in myocardial infarction and cardioprotection induced by ischemic conditioning in rats. ProtectomiRs may be important therapeutics for cardioprotection.

Purpose

We aimed to identify protectomiRs in a translational porcine model of reperfused acute myocardial infarction (AMI) and cardioprotection, and validate their cardiocytoprotective effect.

Methods

We used cardiac tissue samples from our previous study in closed-chest AMI model in domestic pigs. Pigs were subjected to sham operation (Sham), ischemia/reperfusion to induce AMI (AMI) or preconditioning (IPreC), postconditioning (IPostC), and remote perconditioning (RIPerC). Tissue samples were collected from the infarcted region of the left ventricles. MiRNA expression pattern was detected by high-throughput qRT-PCR. Potential protectomiRs were selected by systematic comparison of significant expression changes due to different conditioning stimuli vs. AMI. To validate the cardiocytoprotective effect of potential protectomiRs, isolated rat cardiomyocytes were transfected with specific miRNA mimics or inhibitors (antagomiRs) of the selected protectomiRs, and the survival of cells was measured after simulated ischemia/reperfusion injury.

Results

Expression of 221 miRNAs was assessed. Expression of 57 microRNAs were changed by IPreC, 54 by IPostC and 68 by RIPerC  as compared to AMI (min. 1,5×log2 fold-change, -log10p>1,31 vs. AMI). Expression of 14 microRNAs changed significantly due to all three conditionings vs. AMI (10 miRNAs were downregulated and 4 upregulated). Rat homologs of these 14 protectomiR candidates were identified and 13 showed 100% sequence homology with the original pig miRNAs. The selected miRNAs (9 antagomiRs and 4 miRNA mimics) were transfected in isolated rat cardiomyocytes. Modulation of 2 mimics of these miRNAs significantly improved the survival of cells after ischemia/reperfusion injury (due to intellectual property protection, we do not disclose the protectomiRs here).

Conclusion

Here we identified 2 miRNAs in a clinically relevant porcine model of AMI that can be potential therapeutic protectomiRs.

Transcriptomic analysis and comparative characterization of rat H9C2, human AC16 and murine HL-1 cardiac cell lines

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020 research and innovation programme

National Research, Development and Innovation Fund of Hungary

Background

Cardiac cell lines and primary cell cultures are widely used to model various cardiovascular diseases in vitro. Despite the increasing number of publications using these models, limitations of these cell lines are still undetermined.

Purpose

The aim of our study was to compare the most commonly used cardiac cell lines to primary cultures and to mature cardiac tissues by transcriptomic analysis and morphological characterization.

Methods

H9C2 (rat), AC16 (human) and HL-1 (mouse) cardiac cell lines were differentiated towards a phenotype more resembling cardiomyocytes, by methods most widely used in the literature, and cells were harvested at stages of proliferation and differentiation. Whole left ventricular tissue, neonatal primary cardiac myocytes isolated from mice and rats, or human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM) were applied as references. Transcriptome analysis and immunocytochemical detection of cardiac structural proteins were performed on all cell models.

Results

RNA expression of cardiac markers (e.g. Tnnt2, Ryr2, Tnni3) was markedly lower in cell lines compared to primary cells or hiPSC-CM and adult tissue controls. Differentiation procedures induced a significant increase in cardiac- and decrease in embryonic markers in AC16 and H9C2 lines; however, the overall expression pattern of investigated genes in all cell lines showed significant differences in comparison to corresponding myocardium or primary cultures. Immunocytochemistry confirmed low expressions of structural protein alpha-actinin and troponin I in cell lines.

Conclusion

Expression patterns of cardiomyocyte markers and mRNA profile indicates low-to-moderate similarity of cell lines to primary cells/cardiac tissues regardless the differentiation protocol used. These limitations should be taken into account while choosing cells as in vitro platforms to model cardiomyocytes and cardiovascular diseases.

Helium conditioning increases cardiac fibroblast migration which effect is not propagated via soluble factors or extracellular vesicles

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Project was supported by the National Research, Development and Innovation Office of Hungary

Background

Helium inhalation induces cardioprotection against ischemia/reperfusion injury, of which cellular mechanism is not fully elucidated. Extracellular vesicles (EVs) are cell-derived, nano-sized membrane vesicles which play role in cardioprotective mechanisms, but their function in helium-conditioning (HeC) is not elucidated.

Purpose

To investigate, how HeC affects cardiac fibroblasts and if their HeC-induced EVs or other secreted factors mediates remodeling of the cardiac tissue.

Methods

Neonatal rat cardiac fibroblasts (NRCF) were exposed to glucose deprivation and HeC rendered by four cycles of 95% helium + 5% CO2 for one hour, followed by one hour of normal culturing conditions. 40 hours later, NRCF migration was analyzed and Western Blot and quantitative PCR were used to analyze the expression of fibroblast to myofibroblast transformation markers. From the cell supernatant, medium-sized extracellular vesicles (mEVs) were isolated with differential centrifugation and analyzed with WB, transmission electron microscopy and nanoparticle tracking analysis. Supernatant of HeC-treated NRCF was transferred to naïve NRCF or immortalized human umbilical vein endothelia cells (HUVEC/TERT2) and migration and in vitro angiogenesis assay was performed.

Results

HeC accelerated the migration of NRCF. Meanwhile, HeC did not increase the expression of myofibroblast markers. HeC tended to decrease mEV secretion of NRCFs, but supernatant of HeC-NRCF neither accelerate the migration of naïve NRCF, nor affect the angiogenic potential of HUVEC/TERT2.

Conclusion

Since HeC increased the migration of NRCF but HeC-NRCF mEVs did not affect the function of remote cells, HeC may exert its cardioprotective effect via NRCFs, but not affect cardiac remodeling remotely, via NRCF mEVs.

Differentiating sepsis from similar groups of symptoms at triage level in emergency care

OBJECTIVES

Conditions that have similar initial presentations as sepsis may make early recognition of sepsis in an emergency room (ER) difficult. We investigated whether selected physiologic and metabolic parameters can be reliably used in the emergency department to differentiate sepsis from other disease states that mimic it, such as dehydration and stroke.

METHODS

Loess regression on retrospective follow-up chart data of patients with sepsis-like symptoms (N = 664) aged 18+ in a large ER in Hungary was used to visualize/identify cutoff points for sepsis risk. A multivariate logistic regression model based on standard triage data was constructed with its corresponding receiver operating characteristic (ROC) curve and compared with another model constructed based on current sepsis guidelines.

RESULTS

Age, bicarbonate, HR, lactate, pH, and body temperature had U, V, W, or reverse U-shaped associations with identifiable inflexion points, but the cutoff values we identified were slightly different from guideline cutoff values. In contrast to the guidelines, no inflexion points could be observed for the association of sepsis with SBP, DPB, MAP, and RR and therefore were treated as continuous variables. Compared to the guidelines-based model, the triage data-driven final model contained additional variables (age, pH, bicarbonate) and did not include lactate. The data-driven model identified about 85% of sepsis cases correctly, while the guidelines-based model identified only about 70% of sepsis cases correctly.

CONCLUSION

Our findings contribute to the growing body of evidence for the necessity of finding improved tools to identify sepsis at early time points, such as in the ER.

High-Order Phase-Dependent Asymmetry in the Above-Threshold Ionization Plateau

Above-threshold ionization spectra from cesium are measured as a function of the carrier-envelope phase (CEP) using laser pulses centered at 3.1  μm wavelength. The directional asymmetry in the energy spectra of backscattered electrons oscillates three times, rather than once, as the CEP is changed from 0 to 2π. Using the improved strong-field approximation, we show that the unusual behavior arises from the interference of few quantum orbits. We discuss the conditions for observing the high-order CEP dependence, and draw an analogy with time-domain holography with electron wave packets.

Systematic analysis of different pluripotent stem cell-derived cardiac myocytes as potential testing model for cardiocytoprotection

INTRODUCTION

Stem cell-derived cardiac myocytes are potential sources for testing cardiocytoprotective molecules against ischemia/reperfusion injury in vitro.

MATERIALS AND METHODS

Here we performed a systematic analysis of two different induced pluripotent stem cell lines (iPSC 3.4 and 4.1) and an embryonic stem cell (ESC) line-derived cardiac myocytes at two different developmental stages. Cell viability in simulated ischemia/reperfusion (SI/R)-induced injury and a known cardiocytoprotective NO-donor, S-nitroso-n-acetylpenicillamine (SNAP) was tested.

RESULTS

After analysis of full embryoid bodies (EBs) and cardiac marker (VCAM and cardiac troponin I) positive cells of three lines at 6 conditions (32 different conditions altogether), we found significant SI/R injury-induced cell death in both full EBs and VCAM+ cardiac cells at later stage of their differentiation. Moreover, full EBs of the iPS 4.1 cell line after oxidative stress induction by SNAP was protected at day-8 samples.

CONCLUSION

We have shown that 4.1 iPS-derived cardiomyocyte line could serve as a testing platform for cardiocytoprotection.

Fecal expression of Escherichia coli lysine decarboxylase (LdcC) is downregulated in E-cadherin negative lobular breast carcinoma

Breast cancer is characterized by oncobiosis, the abnormal composition of the microbiome in neoplastic diseases. The biosynthetic capacity of the oncobiotic flora in breast cancer is suppressed, as suggested by metagenomic studies. The microbiome synthesizes a set of cytostatic and antimetastatic metabolites that are downregulated in breast cancer, including cadaverine, a microbiome metabolite with cytostatic properties. We set out to assess how the protein expression of constitutive lysine decarboxylase (LdcC), a key enzyme for cadaverine production, changes in the feces of human breast cancer patients (n = 35). We found that the fecal expression of Escherichia coli LdcC is downregulated in lobular cases as compared to invasive carcinoma of no special type (NST) cases. Lobular breast carcinoma is characterized by low or absent expression of E-cadherin. Fecal E. coli LdcC protein expression is downregulated in E-cadherin negative breast cancer cases as compared to positive ones. Receiver operating characteristic (ROC) analysis of LdcC expression in lobular and NST cases revealed that fecal E. coli LdcC protein expression might have predictive values. These data suggest that the oncobiotic transformation of the microbiome indeed leads to the downregulation of the production of cytostatic and antimetastatic metabolites. In E-cadherin negative lobular carcinoma that has a higher potential for metastasis formation, the protein levels of enzymes producing antimetastatic metabolites are downregulated. This finding represents a new route that renders lobular cases permissive for metastasis formation. Furthermore, our findings underline the role of oncobiosis in regulating metastasis formation in breast cancer.

Quantum Optical Signatures in a Strong Laser Pulse after Interaction with Semiconductors

Electrodynamical processes induced in complex systems like semiconductors by strong electromagnetic fields have traditionally been described using semiclassical approaches. Although these approaches allowed the investigation of ultrafast dynamics in solids culminating in multipetahertz electronics, they do not provide any access to the quantum-optical nature of the interaction, as they treat the driving field classically and unaffected by the interaction. Here, using a full quantum-optical approach, we demonstrate that the subcycle electronic response in a strongly driven semiconductor crystal is imprinted in the quantum state of the driving field resulting in nonclassical light states carrying the information of the interaction. This vital step towards strong-field ultrafast quantum electrodynamics unravels information inaccessible by conventional approaches and leads to the development of a new class of nonclassical light sources.

Application of water framework directive in Hungary: development of biological classification systems

The classification according to the Water Framework Directive (WFD) includes numerous challenges in contrast with the previously applied water qualification standards. The most important element of the ecological status, the biological one, is based on five groups of living organisms: phytoplankton, phytobenthon, macrophytes, macro-invertebrates and fish. The results of a three-year research project financed by the Ministry of Environment and Water (MoEW) and the Hungarian Academy of Sciences (HAS) are reported in this work. The objective of the project was the elaboration of a proposal for biological classification according to the WFD for the related groups of living organisms. In the course of the project the biological characteristics to be measured were selected for each of the above listed groups which served as the basic data for Biological Quality Elements (BQEs). In the BQEs we estimated the type-specific reference values for most of the Hungarian surface water types. Then we created the structure of the qualification system for these groups, including specification of class boundaries between the five classes for the Environmental Quality Ratio (EQR) values on the basis of expert estimation. A Non-Taxonomic Periphyton Index (NTPI, not included in the WFD) was also developed and tested for qualification. The elaborated classification systems were tested on the basis of existing scarce data for numerous Hungarian water types.

Comparison of body measurements of beef cows of different breeds

Abstract. Body measurements of 110 beef cows of 9 breeds (Hungarian Simmental, Hereford, Aberdeen Angus, Red Angus, Lincoln Red, Shaver, Charolais, Limousin and Blonde d’Aquitaine) were taken in December 2004. The absolute, relative measurements and measurement indices moreover correlations between age, live weight and measurements were evaluated and compared for the mentioned breeds. Animals in study were born between 1989 and 2002, kept on the same condition on peat-bog soil pasture at Keszthely. Significant differences (P<0.05) were found among breeds in most of the body measurements. Blonde d’ Aquitaine was the heaviest in live weight (638 kg), highest as for the height at withers (142.5 cm), height at rump (146.6 cm) and length of the body (151.5 cm). Limousin had longest measurements as for the length of the rump (47.4 cm) and width of the rump (58.3 cm). Shaver had the longest width between shoulders (52.9 cm) and width of the head (25.1 cm) while Lincoln Red the longest length of the head (52.8 cm). The correlations between live weight and measurements were medium or strong positive (r = 0.40–0.83), between age and measurements slight positive (r = 0.01–0.46), among the different measurements medium or strong positive (r = 0.22–0.81).

The age at first calving and the longevity of beef cows in Hungary

Abstract. The length of time beef cows spend in production is an important component of the rentability of beef cattle husbandry. In spite of this fact, very few publications have dealt with this trait, either in Hungary or abroad. Therefore the aim of the present study was to evaluate some of the age parameters of beef cows related to the production period. A database of 2115 cows belonging to five breeds (Hungarian Grey, Hereford, Aberdeen Angus, Limousin, Charolais) and two crossbred genotypes (Simmental x Hereford F1, Simmental x Limousin F1) born between 1977–1992 was evaluated. Age at first calving (AFC), age at culling (ACU), moreover longevity (LONG) were studied. Longevity is defined as the number of years from first calving to culling. The mean values of AFC, ACU and LONG obtained were 2.71, 9.47 and 6.77 years, respectively. Breed/genotype and birth year had significant influence (P<0.01) on each evaluated trait, whereas birth month statistically affected only the AFC. Ages at first calving of the different breeds and genotypes were: 3.51, 2.08, 2.76, 2.82, 3.02, 2.03, 2.62 years, respectively. Hereford crossbred and purebred cows were the youngest, whereas Hungarian Grey cows were the oldest at first calving. Ages of culling of the evaluated breeds and genotypes were as follows: 12.42, 11.09, 11.03, 10.61, 10.89, 12.73, 8.15 years, respectively. The longest life span was reached by Hereford crossbred and Hungarian Grey and the shortest by Limousin crossbred cows. This trait shows a decreasing trend (from 15.35 years to 5.91 years) from the birth year of 1977 to 1992. The longevity values of the mentioned breeds and genotypes were: 8.59, 9.08, 8.29, 7.81, 7.91, 10.79, 5.55 years, respectively. Hereford crossbred and purebred cows had the longest, Limousin crossbred cows the shortest productive lives. This trait also shows a decreasing trend (from 12.45 to 3.31 years) in the case of cows born between 1977 and 1992.

Nanomechanical properties of desmin intermediate filaments

Desmin intermediate filaments play important role in the mechanical integrity and elasticity of muscle cells. The mechanisms of how desmin contributes to cellular mechanics are little understood. Here, we explored the nanomechanics of desmin by manipulating individual filaments with atomic force microscopy. In complex, hierarchical force responses we identified recurring features which likely correspond to distinct properties and structural transitions related to desmin's extensibility and elasticity. The most frequently observed feature is an initial unbinding transition that corresponds to the removal of approximately 45-nm-long coiled-coil dimers from the filament surface with 20-60 pN forces in usually two discrete steps. In tethers longer than 60 nm we most often observed force plateaus studded with bumps spaced approximately 16 nm apart, which are likely caused by a combination of protofilament unzipping, dimer-dimer sliding and coiled-coil-domain unfolding events. At high stresses and strains non-linear, entropic elasticity was dominant, and sometimes repetitive sawtooth force transitions were seen which might arise because of slippage within the desmin protofilament. A model is proposed in which mechanical yielding is caused by coiled-coil domain unfolding and dimer-dimer sliding/slippage, and strain hardening by the entropic elasticity of partially unfolded protofilaments.

Morbidity of laparoscopic extraperitoneal versus transperitoneal radical prostatectomy verus open retropubic radical prostatectomy

OBJECTIVE

Morbidity and postoperative pain after extraperitoneal (E-LRPE) and transperitoneal (T-LRPE) laparoscopic radical prostatectomy was compared to open extraperitoneal radical prostatectomy (O-RPE).

MATERIAL AND METHODS

Between January 2002 and October 2003, we evaluated 41 E-LRPE, 39 T-LRPE and 41 O-RPE prospectively. All operations were performed as standard procedures by the same group of surgeons and perioperative results and complications were evaluated. Pain management was performed with tramadol 50-100 mg on demand, and no other form of anaesthesia was given. Postoperative pain was assessed daily in all patients quantifying analgesic requirement and evaluation of Visual Analogue Scale (VAS). All patients had at least a 12 month follow-up.

RESULTS

Mean age, prostate volume, PSA and Gleason score were comparable between all three groups (p>0.05). Mean blood loss was lower with laparoscopy (189+/-140 and 290+/-254 ml), as compared to 385+/-410 ml for O-RPE (p=0.002). However, mean operating times were significantly longer in L-TRPE (279+/-70 min) as compared to E-LRPE (217+/-51 min) and O-RPE (195+/-72 min) (p<0.001), but E-LRPE and O-RPE showed no statistical difference (p=0.1143). Average VAS score on the 1st and 5th postoperative day for E-LRPE versus T-LRPE versus O-RPE was 4.9+/-1.0 versus 7.8+/-1.5 versus 5.8+/-1.9 and 1.6+/-0.9 versus 2.3+/-1.2 versus 2.3+/-0.9 respectively, which was significant lower (p=0.02) between E-LRPE versus T-LRPE (p<0.001) and O-RPE (p=0.008), but equal (p=0.655) between T-LRPE and O-RPE since postoperative day 3. Mean tramadol analgesic consumption within the first postoperative week was 290 versus 490 versus 300 mg respectively, which was statistical different between E-LRPE and T-LRPE (p<0.001), O-RPE and T-LRPE (p<0.001), but not between E-LRPE and O-RPE (p=0.550). Statistical analysis revealed a strong correlation of urinary leakage with increased postoperative pain (p=0.029) in all groups, especially for T-LRPE (p=0.007). Likewise, increased operating times (>240 min) were associated with increased post-operative pain (p=0.049). Full continence defined as no pads at one year was achieved in 36/41 (88%, E-LRPE) versus 33/39 (85%, T-LRPE) versus 33/41 (81%, O-RPE), respectively (p=0.2).

CONCLUSION

E-LRPE resulted in a significant subjective (VAS Score, p<0.001) and objective (analgetic consumption, p<0.001) pain reduction compared to T-LRPE, but only in VAS Score compared to O-RPE (p=0.008). Analgetic consumption during first postoperative week was equal in E-LRPE (290 mg) and O-RPE (300 mg) (p=0.550). Shorter operating times, lower urinary leakage rates, lower stricture rates and lower blood loss in E-LRPE compared to T-LRPE are mainly explained due to the long learning curve in LRPE, which we did not overcome yet, and not due to the approach (extraperitoneal versus transperitoneal).

Effect of trabeculectomy on ocular blood flow

BACKGROUND/AIM

Current evidence suggests that vascular insufficiencies in the optic nerve head play an important part in the pathogenesis of glaucomatous optic neuropathy. Trabeculectomy is the most common operative procedure for the treatment of medically uncontrolled glaucoma. This study was conducted to investigate whether trabeculectomy may improve ocular haemodynamics.

METHODS

30 patients with primary open angle glaucoma about to undergo trabeculectomy were included in the study. Patients were evaluated before surgery and at 2 and 10 weeks after trabeculectomy. Optic nerve head blood flow (OnhBF) was assessed with scanning laser Doppler flowmetry. Fundus pulsation amplitude (FPA) measurements were obtained with laser interferometry.

RESULTS

Because of the decrease in intraocular pressure there was a significant increase in ocular perfusion pressure (OPP) following trabeculectomy (18.5% (SD 12.0%) and 19.0% (17.1%) at 2 and 10 weeks postoperatively; p <0.001). A significant increase in OnhBF was observed after trabeculectomy (11.6% (16.4%) and 16.2% (20.2%) for each postoperative visit, respectively; p <0.001). FPA was also significantly higher compared with baseline values (17.2% (17.3%) and 17.4% (16.3%), respectively; p <0.001). A significant association between the increase in OPP and the increase in OnhBF and FPA was observed 10 weeks after surgery (r = 0.47; p = 0.009, and r = 0.50; p = 0.005, respectively).

CONCLUSION

The results of this study suggest that trabeculectomy improves ocular blood flow in patients with chronic open angle glaucoma.

PET studies on the brain uptake and regional distribution of [11C]vinpocetine in human subjects

OBJECTIVES

Vinpocetine is a compound widely used in the prevention and treatment of cerebrovascular diseases. It is still not clear whether the drug has a direct and specific effect on neurotransmission or its effects are due to extracerebral actions, such as changes in cerebral blood flow. The main objective of the present investigation was to determine the global uptake and regional distribution of radiolabelled vinpocetine in the human brain in order to explore whether it may have direct central nervous system effects.

MATERIAL AND METHODS

Three healthy subjects were examined with positron emission tomography and [11C]vinpocetine. The regional uptake was determined in anatomically defined volumes-of-interest. The fractions of [11C]vinpocetine and labelled metabolites in plasma were determined using high pressure liquid chromatography.

RESULTS

The uptake of [11C]vinpocetine in brain was rapid and 3.7% (mean; n = 4) of the total radioactivity injected was in brain 2 min after radioligand administration. The uptake was heterogeneously distributed among brain regions. When compared with the cerebellum, an a priori reference region, the highest regional uptake was in the thalamus, upper brain stem, striatum and cortex. Following an initial peak, the total concentration of radioactivity in blood was relatively stable with time, whereas the concentration of the unchanged compound decreased with time in an exponential manner.

CONCLUSION

Vinpocetine, administered intravenously in humans, readily passes the blood-brain barrier and enters the brain. Its regional uptake and distribution in the brain is heterogeneous, indicating binding to specific sites. The brain regions showing increased uptake in the human brain correspond to those in which vinpocetine has been shown to induce elevated metabolism and blood flow. These observations support the hypothesis that vinpocetine has direct neuronal actions in the human brain.

Response of retinal blood flow to CO2-breathing in humans

PURPOSE

To investigate the effect of systemic hypercapnia on retinal hemodynamics in humans.

METHODS

We studied the effect of breathing a mixture of normal air with 5% CO2 for 13 minutes in ten healthy young male volunteers, using the Zeiss retinal vessel analyzer for continuous measurement of retinal vessel diameter and the blue-field entoptic technique to quantify retinal white blood cell flux. In eight other subjects the effect of hypercapnia was measured with the Zeiss retinal vessel analyzer and by laser Doppler velocimetry to establish retinal blood flow velocity.

RESULTS

Retinal arterial and venous vessel diameters increased by a maximum of 4.2% and 3.2%, respectively. Peak effect was observed after 3 minutes of breathing the mixture of normal air with 5% CO2. During hypercapnia red blood cell velocity increased 11.7% and, accordingly, retinal blood flow increased 19.1%. White blood cell density and velocity rose significantly during hypercapnia, resulting in an increase in white blood cell flux (19.2%).

CONCLUSIONS

Our data indicate that CO2 induces vasodilation in retinal arteries and retinal veins. Retinal blood flow and perimacular white blood cell flux increased to the same extent in subjects breathing a mixture of normal air with 5% CO2.

Ocular hyperperfusion following onset of intensified insulin therapy is inversely correlated with plasma endothelin-1 in Type I diabetes

AIMS/HYPOTHESIS

It has been reported that improvement of metabolic control by intensified insulin therapy in patients with Type I (insulin-dependent) diabetes mellitus is associated with alterations in ocular blood flow. We hypothesized that these changes in ocular blood flow could be associated with alterations of plasma insulin, glucose or endothelin concentration.

METHODS

In 16 patients with Type I diabetes ocular haemodynamic parameters were assessed daily during the first 5 days of institution of intensified insulin therapy and plasma concentrations of glucose, insulin, and endothelin-1 plasma were measured. Retinal white blood cell flux was estimated with the blue field entoptic technique. Pulsatile choroidal blood flow was assessed by laser interferometric measurement of fundus pulsation amplitude.

RESULTS

Retinal white blood cell flux ( p=0.0015) and ocular fundus pulsation amplitude ( p<0.001) increased during institution of strict metabolic control. Changes in ocular haemodynamic variables were inversely correlated with concentrations of plasma ET-1, but not with that of insulin or glucose.

CONCLUSIONS/INTERPRETATION

These data indicate that institution of improved metabolic status is paralleled by rapid changes in the production of ET-1, which could in turn affect ocular perfusion.

Ocular blood flow in patients infected with human immunodeficiency virus

PURPOSE

Alterations of ocular blood flow may play a role in the pathophysiology of human immunodeficiency virus (HIV) related retinal microvasculopathy. In this study ocular blood flow was investigated in patients with HIV infection.

DESIGN

In a prospective, cross-sectional study ocular blood flow was measured in 37 eyes of consecutive HIV- infected persons and compared with the data of age-matched healthy controls. This sample size was calculated based on an alpha-error of 0.5 and a beta-error of 0.8.

METHODS

Macular white blood cell flow, fundus pulsation amplitude, and blood flow velocities in the retrobulbar vessels were measured with blue field entoptic technique, laser interferometry, and Doppler sonography, respectively. Immunologic and ophthalmologic status was evaluated from each patient.

RESULTS

Mean CD4+ cell count of the HIV-infected persons was 206.8 +/- 145.6 cells/mm(3). In five patients HIV-related retinopathy was observed. A significant reduction in leukocyte density was seen in HIV infected persons (82.2 +/- 23.4) as compared with the control group (102.0 +/- 28.4; P =.019). The resistive index in the central retinal artery was higher in HIV infected patients (0.77 +/- 0.05) as compared with the controls (0.74 +/- 0.04; P =.04). The other hemodynamic parameters were not different between groups. No correlation of flow parameters and CD4+ cell count or HIV-related retinopathy was observed.

CONCLUSIONS

Decreased macular leukocyte density was detected in HIV infected persons. Our study suggests that abnormal retinal hemodynamics in individuals infected with HIV may be involved in the pathogenesis of HIV-related microvasculopathy.

A double masked placebo controlled study on the effect of nifedipine on optic nerve blood flow and visual field function in patients with open angle glaucoma

AIMS

To investigate whether nifedipine affects ocular perfusion or visual fields in open angle glaucoma patients.

METHODS

In a parallel group study nifedipine or placebo was administered for 3 months (n = 30). Ocular fundus pulsation amplitude (FPA), cup blood flow (Flowcup) and visual field mean deviation (MD) were measured.

RESULTS

Five patients receiving nifedipine discontinued due to adverse events. Nifedipine did not affect FPA [difference: 0.3 microm (95% CI -0.3,0.9); P = 0.70], Flowcup: [difference: -9 rel.units (95% CI -133,114); P = 0.99], or MD [difference: 0.2dB (95% CI -2.2,2.7); P = 0.51] vs placebo.

CONCLUSIONS

Systemic nifedipine is not well tolerated in glaucoma patients and exerts no effect on visual fields or ocular perfusion.

Effect of topical brimonidine on intraocular pressure after small incision cataract surgery

PURPOSE

To evaluate the effect of brimonidine 0.2% on intraocular pressure (IOP) after small incision cataract surgery.

SETTING

Department of Ophthalmology, University of Vienna, Vienna, Austria.

METHODS

This prospective randomized study comprised 80 eyes of 40 patients scheduled for small incision cataract surgery in both eyes. In each patient, 1 eye was randomly assigned to receive 1 drop of brimonidine 0.2% or no treatment (control) immediately after surgery. The fellow eye received the other assigned treatment. All patients had standardized surgery by the same surgeon with sodium hyaluronate 1%, a temporal 3.5 mm sutureless posterior limbal incision, phacoemulsification, and implantation of a foldable intraocular lens. The IOP was measured preoperatively as well as 6 and 20 to 24 hours and 1 week postoperatively.

RESULTS

Six hours after surgery, the mean increase in IOP was 4.7 mm Hg +/- 6.1 (SD) in the brimonidine group and 4.6 +/- 5.3 mm Hg in the control group. In each group, 17 eyes (43%) had an IOP increase of 5 mm Hg or more. Twenty to 24 hours after surgery, the mean increase in IOP was 1.5 +/- 4.2 mm Hg in the brimonidine group and 1.6 +/- 4.4 mm Hg in the control group. There were no statistically significant between-group differences at any measurement.

CONCLUSIONS

In both groups, IOP significantly increased 6 hours and 20 to 24 hours after small incision cataract surgery. Brimonidine 0.2% failed to reduce the IOP increase observed after small incision cataract surgery.

Intraindividual comparison of the effects of a fixed dorzolamide-timolol combination and latanoprost on intraocular pressure after small incision cataract surgery

To compare the effect of a fixed dorzolamide-timolol combination with that of latanoprost on intraocular pressure (IOP) after small incision cataract surgery. Department of Ophthalmology, University of Vienna, Vienna, Austria. This prospective randomized study comprised 60 eyes of 30 patients scheduled for small incision cataract surgery in both eyes. The patients were randomly assigned to receive 1 drop of a fixed dorzolamide-timolol combination or latanoprost immediately after cataract surgery in the first eye. The second eye received the other antiglaucomatous agent. Cataract surgery was performed under sodium hyaluronate 1% with a temporal 3.5 mm sutureless posterior limbal incision, phacoemulsification, and implantation of a foldable intraocular lens. The IOP was measured preoperatively as well as 6 and 20 to 24 hours and 1 week postoperatively. Six hours after surgery, the mean IOP decreased by -0.8 mm Hg +/- 3.2 (SD) (P =.184) in the dorzolamide-timolol group and increased by 3.6 mm Hg +/- 3.5 (P <.001) in the latanoprost group. Twenty to 24 hours after surgery, the mean IOP decreased by -2.8 +/- 2.4 mm Hg (P <.001) in the dorzolamide-timolol group and increased by 0.6 +/- 3.5 mm Hg (P =.353) in the latanoprost group. The differences between groups were significant at 6 hours (P <.001) and 20 to 24 hours (P <.001). The fixed dorzolamide-timolol combination was more effective than latanoprost in reducing IOP after small incision cataract surgery. Only the fixed dorzolamide-timolol combination prevented a postoperative IOP increase and occasional IOP spikes of 30 mm Hg or higher.

Posterior continuous curvilinear capsulorhexis with hydrogel and silicone intraocular lens implantation: development of capsulorhexis size and capsule opacification

PURPOSE

To evaluate the influence of primary posterior continuous curvilinear capsulorhexis (PCCC) on capsule opacification development and capsular bag changes within the first year after cataract surgery with 2 intraocular lenses (IOLs) of comparable design but different material.

SETTING

Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria.

METHODS

Thirty-seven patients with age-related cataract had bilateral small incision cataract surgery with a PCCC performed after capsular tension ring insertion. One eye was randomly assigned to receive a hydrogel IOL and the other eye, a silicone IOL. Standardized digital retroillumination photographs were taken 1 day, 1 week, and 1, 3, 6, and 12 months after surgery to evaluate changes in the dimensions of the anterior and posterior capsulorhexis opening area and the presence of anterior and posterior capsule opacification.

RESULTS

The area of the anterior continuous curvilinear capsulorhexis (ACCC) opening was significantly reduced during the first 6 postoperative months. The shrinkage was more pronounced (-25%) in the silicone IOL group than in the hydrogel IOL group. Ten percent of eyes with a silicone IOL had marked shrinkage of the ACCC. The area of the PCCC did not change in eyes with a hydrogel IOL but was larger (+20%) in eyes with a silicone IOL. Anterior ongrowth was observed in 60% in the hydrogel group and in no eye in the silicone group. Anterior capsule fibrosis was observed in 90% in the silicone group and in 20% in the hydrogel group. Total closure of the PCCC was not observed within the first year, but posterior ongrowth was observed in 40% in the hydrogel group and 10% in the silicone group.

CONCLUSIONS

Anterior capsulorhexis shrinkage with concomitant posterior capsulorhexis enlargement was observed in eyes with a silicone IOL. The hydrogel IOL induced more ongrowth on the anterior and posterior IOL surfaces, whereas the silicone IOL induced more anterior capsule fibrosis. Total closure of the PCCC was not observed within the first year after surgery.

Substituted phenoxyalkylpiperazines as dopamine D3 receptor ligands

A novel series of potential antipsychotic agents were prepared by combination of condensed heterocycles containing bridgehead nitrogen with (2-methoxyphenyl)piperazine using phenoxyalkyl spacer of variable length. The affinity of the compounds was determined at rat cloned D3 and rat D2, 5-HT1A receptors by an vitro receptor binding assay. The D3 selectivity of the compounds was calculated from the Ki values.

Morphological appearance and size of contact zones of piggyback intraocular lenses

PURPOSE

To characterize the morphology, size, and change in size of the contact zone of piggyback intraocular lenses (IOLs) of different materials and optic designs.

SETTING

Department of Ophthalmology, Vienna General Hospital, Vienna, Austria.

METHODS

In a prospective study, 9 eyes of 7 patients received piggyback IOLs of the following materials: poly(methyl methacrylate) (PMMA), acrylic, hydrogel, and silicone. The contact zone between the anterior and posterior IOLs was photodocumented from 1 day to 1 year after surgery using specular microscopy. The contact zone area was measured.

RESULTS

A contact zone was present with all IOL materials studied. The area of contact, however, differed significantly. With PMMA IOLs, the contact zone was small and surrounded by Newton rings, indicating the tiny gap between the IOLs. With IOLs of soft material, such as silicone and hydrogel, it was larger than with PMMA IOLs and had a slightly irregular shape. With foldable acrylic IOLs, it was regular, round, and slightly larger than with the soft materials. The contact area enlarged primarily during the first 3 months after surgery. After 1 year, 2 eyes with acrylic piggyback IOLs had a membrane formation around the contact zone and 2 eyes developed Elschnig pearls between the IOLs.

CONCLUSION

In piggyback IOL eyes, the shape and size of the contact zone were strongly dependent on the IOL material and optic design. Contact area enlargement seemed to be induced by capsule shrinkage. Fibrous membrane formation around the contact zone and Elschnig pearl formation between the piggyback IOLs were long-term complications of this technique.

Intraocular pressure rise after small incision cataract surgery: a randomised intraindividual comparison of two dispersive viscoelastic agents

AIM

To evaluate the effects of the dispersive viscoelastic agents Ocucoat (hydroxypropyl methylcellulose 2%) and Viscoat (sodium chondroitin sulphate 4%-sodium hyaluronate 3%) on postoperative intraocular pressure (IOP) after bilateral small incision cataract surgery.

METHODS

This prospective, randomised study comprised 80 eyes of 40 consecutive patients with age related cataract in both eyes scheduled for bilateral small incision cataract surgery. The patients were randomly assigned to receive Ocucoat or Viscoat during cataract surgery of the first eye. The second eye was operated later and received the other viscoelastic agent. Cataract surgery was performed with a temporal 3.2 mm sutureless posterior limbal incision, phacoemulsification, and implantation of a foldable silicone intraocular lens. The IOP was measured preoperatively as well as 6 hours, 20-24 hours, and 1 week postoperatively.

RESULTS

At 6 hours after surgery the mean IOP increased by 4.6 (SD 5.1) mm Hg in the Ocucoat group (p<0.001) and by 8.6 (8.1) mm Hg in the Viscoat group (p<0.001). The increase was significantly higher in the Viscoat group than in the Ocucoat group (p=0.004). Intraocular pressure spikes of 30 mm Hg or more occurred in two eyes in the Ocucoat and in nine eyes in the Viscoat group (p=0.023); 20-24 hours and 1 week postoperatively the mean IOP was not statistically different.

CONCLUSION

These findings indicate that Viscoat causes a significantly higher IOP increase and significantly more IOP spikes than Ocucoat in the early period after small incision cataract surgery.