Comparison of effect of CTG + STan with CTG alone on emergency Cesarean section rate: STan Australian Randomized controlled Trial (START)

OBJECTIVE

To investigate whether use of ST analysis of the fetal electrocardiogram (STan) as an adjunct to continuous cardiotocography (CTG) reduces the rate of emergency Cesarean section (EmCS) compared with CTG alone.

METHODS

This was a randomized controlled trial of patients with a singleton fetus in cephalic presentation at ≥ 36 weeks' gestation, requiring continuous electronic fetal monitoring during labor at a tertiary maternity hospital in Adelaide, Australia, between January 2018 and July 2021. Participants were randomized to undergo CTG + STan or CTG alone. The calculated sample size was 1818 participants. The primary outcome was EmCS. Secondary outcomes included metabolic acidosis, a composite adverse perinatal outcome, and other maternal and neonatal morbidity and safety outcomes.

RESULTS

The present study enrolled 970 women, of whom 967 were included in the primary analysis. EmCS occurred in 107/482 (22.2%) deliveries in the CTG + STan arm and in 107/485 (22.1%) in the CTG arm (adjusted relative risk, 1.02 (95% CI, 0.81-1.27); P = 0.89). There was no difference in the rate of adverse maternal or neonatal outcomes between arms.

CONCLUSIONS

The addition of STan as an adjunct to continuous CTG did not reduce the EmCS rate. The smaller-than-anticipated sample size meant that this study was underpowered to detect absolute differences of ≤ 5% and, therefore, this negative finding could be due to a Type-2 error. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Consumer acceptability and validity of m-Health for the detection of adverse events following immunization - The Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) randomised control trial

INTRODUCTION

Monitoring for adverse events following immunisation (AEFI) is critical for vaccine pharmacovigilance. Given the global and expanding availability of mobile phones their utility for consumer-based vaccine safety surveillance is of interest but little is known about consumer acceptability. This study nested within the Stimulated Telephone Assisted Rapid Safety Surveillance (STARSS) randomised control trial sought to evaluate the acceptability of SMS for AEFI surveillance.

METHODS

The primary STARSS study was a multi-centre RCT evaluating the efficacy of repeated SMS prompts for AEFI surveillance with participants being adult vaccinees or parents of children receiving any vaccine. This nested study enrolled primary RCT participants who completed a detailed computer assisted telephone interview to determine their attitudes towards SMS-based surveillance and ascertain their knowledge and attitudes toward vaccine safety, efficacy, data privacy and use of electronic health records. Attitudes to surveillance and related behaviour were used as measures of acceptability.

RESULTS

20% (1200/6555) of the participants were enrolled and 1139 completed the full-length questionnaire. 96% indicated that SMS-based surveillance after immunisation to check the safety of the vaccine "should be done" but 62% of all respondents said it should be done but consent should be sought first. Neither vaccine safety attitudes nor attitudes toward privacy were associated with opposition to SMS-based surveillance. In terms of SMS related behaviour demographic rather than attitudinal factors were associated with non-compliance.

CONCLUSION

Overall, the attitude towards SMS-based surveillance was very favourable. Experiencing the SMS surveillance has the effect of reducing opposition to an SMS surveillance system, and at the same time increasing the likelihood of a preference for prior consent. Detection of a vaccine safety signal could be impeded in particular demographic groups who are non-compliant and we should undertake further research to understand why these groups are non-compliant and how this can be improved.

Implications of presenting to hospital with AF: the REVIEW AF study

Background

There is a growing burden of hospitalizations due to atrial fibrillation (AF). The implications of hospitalisation to the individual with AF has not been well characterized.

Purpose

To characterise the consequences of presenting to hospital with AF.

Methods

Individuals presenting to the emergency department (ED) of three hospitals in South Australia from March 2013 to February 2014 with a primary diagnosis of AF were enrolled. Based on coding and individual electronic medical record review all re-presentations over follow up were characterised as: 1) AF related; 2) cardiovascular related (excluding AF); or 3) all other causes. Mortality over follow up was also determined.

Results

The study cohort comprised of 437 individuals with an AF related index presentation. Mean age was 69±15 years and 49.9% were male. Individuals were followed for a mean of 3.7±0.4 years. There were 2304 unplanned presentations over follow up. The percentage of the study cohort who presented to the ED or were admitted to hospital over follow up is detailed in Figure 1. Compared to individuals who did not have a hospital admission for AF over follow up, those who were readmitted for AF were more likely to be hypertensive (63.2% vs 49.3%, p<0.001); and have a higher CHA2DS2-VASc score (3.2±1.8 vs 2.7±1.9, p=0.002) and HAS-BLED score (2.0±1.0 vs 1.5±1.1, p<0.001). A total of 71 individuals (16.2%) died during the follow-up period (annual mortality rate of 3.78%).

Conclusions

A hospital presentation with a primary diagnosis of AF identifies individuals at high risk of repeat hospitalisations and death. Urgent studies are needed to improve management of this high-risk cohort.

Figure 1. Repeat hospital presentations in AF

Funding Acknowledgement

Type of funding source: None

Opportunities to reduce the risk of stroke in AF: the REVIEW AF study

Background

Stroke is one of the most devastating complications of atrial fibrillation (AF) and is associated with poor patient outcomes. Recent registry data has demonstrated improved use of stroke prevention therapy with the advent of direct-acting oral anticoagulants, but little data exists in the Australian health care setting.

Purpose

To examine the use of oral anticoagulant therapy in a cohort of individuals presenting to the emergency department (ED) due to AF.

Methods

A total of 437 consecutive individuals who presented to the ED with a primary diagnosis of AF to three tertiary hospitals in our city in South Australia between March 2013 and March 2014 were included. Data were collected retrospectively from electronic medical record review. CHA2DS2-VASc and HAS-BLED scores were calculated and any documented contraindications to the use of oral anticoagulation (OAC) taken in to consideration.

Results

Mean age was 69±15 years and 49.9% were male. A total of 244 (55.8%) individuals had a prior diagnosis of AF at index presentation. 179 (73.4%) of these individuals recorded a CHA2DS2-VASc score of ≥2. A total of 124 of these individuals were appropriately anticoagulated (69.3%) whilst 37 individuals were not treated with OAC and did not have a documented contraindication (20.7%). Anticoagulation status was unknown in 18 individuals due to a lack of documentation (10.0%). A CHA2DS2-VASc score of 0 was recorded in 25 individuals with a prior diagnosis of AF at index presentation with 3 individuals (12%) inappropriately overtreated with OAC. The remaining 193 individuals (44.2%) presented with a first episode of AF. In 129 (66.8%) of these individuals a CHA2DS2-VASc score of ≥2 was recorded and only 10 individuals had a documented contraindication to the use of OAC. In 119 (61.7%) individuals there were no documented contraindications to the use of OAC. In 74 (62.2%) of these presentations OAC was not commenced, whilst in 45 (37.8%) individuals OAC was prescribed.

Conclusions

Significant opportunity exists to improve the use of stroke prevention therapy in AF. Despite repeated opportunities to commence this therapy within the hospital setting, it remains frequently underutilised in individuals at high risk of stroke.

Funding Acknowledgement

Type of funding source: None

Lipid Composition of Photosystem I and II in the Tobacco Mutant Nicotiana tabacum NC 95

The lipids of photosystem II particles, of chloroplasts and leaves are compared in the variegated tobacco mutant NC 95. The mutant differs from other N. tabacum mutants by the phenomenon that it has variegated leaves with green and with yellow-green leaf patches. Chloroplasts from the green leaf areas exhibit photosystem II and photosystem I reactions and have a normal lamellar system with grana and intergrana regions. Chloroplasts from the yellow-green leaf areas, however, yield only photosystem I reactions and have only single stranded isolated thylakoids. Hence, this mutant offers the unique possibility to compare without the use of detergents within the same plant the lipid composition of photosystem II particles with that in intact chloroplasts, exhibiting either photosystem II and I reactions or those exhibiting exclusively photosystem I reactions.

The lipids of photosystem II particles are composed of 37 % glycolipids, 4 % phospholipids, 5 % carotenoids and 54 % chlorophyll. Lipids of chloroplasts with grana stacking are composed of 75% glycolipids, 7 % phospholipids, 2 % carotenoids and 16% chlorophyll. Chloroplasts with single isolated thylakoids have a lipid composition consisting of 8 3 % glycolipids, 14% phospholipids and only 0.5% carotenoids and 2 % chlorophyll. The chloroplast lipid mixture is characterized in comparison to the respective leaf lipid mixture by a 16-17% higher glycolipid portion and by a 13-70% lower phospholipid content.

The main difference in the lipid composition of photosystem I and II consists in the observation that chloroplasts active in only photosystem I contain more than double the amount of glycolipids and the 4-fold amount of phospholipids in comparison to photosystem II active preparations. The amount of monogalactolipid is even 3 times higher in chloroplasts active only in photosystem I when compared to those in photosystem II particles. In photosystem II particles phosphatidylethanolamine is completely lacking and phosphatidylglycerol and phosphatidylinositol occur only in traces.

The fatty acids of the sulfolipid are by 45 % more saturated in the photosystem II particles and the digalactolipids of the photosystem II particles are by 28 % more saturated than in chloroplasts exhibiting photosystem I and II activity.

Interrelationship of Oxygen and Nitrogen Metabolism in the Filamentous Cyanobacterium Oscillatoria chalybea

Filamentous Cyanobacteria. Hydrogen Peroxide, Photosystem II. Nitrogen Metabolism By means of mass spectrometric analysis we have been able to demonstrate H 20 2-production and its decomposition by photosystem II in thylakoids of the filamentous cyanobacterium Oscil­ latoria chalybea. This H2O2-production and its quasi simultaneous decomposition by the S-state system can be readily demonstrated in flash light illumination (K. P. Bader and G. H. Schmid, Biochim. Biophys. Acta 936, 179-186 (1988)) or as shown in the present paper in continuous light at low light intensities. These light conditions correspond essentially to the culturing condition of the organism on nitrate as the sole nitrogen source. Under these conditions, however, electron transport between the two photosystems seems to be mostly disconnected and respiratory activity practically non existent. Under these conditions, on the other hand, nitrate reductase is induced and nitrate reduced. The present paper addresses the question how this organism might solve the metabolic problems of nitrate reduction with such an electron transport system. Tested under high light intensities under which the organism would not grow at all, electron transport between the two photosystems is optimally linked and the system funnels part of its photosynthetically pro­duced electrons into a conventional cyanide-sensitive respiratory electron transport chain and even into an alternative Sham-sensitive (cyanide-insensitive) respiratory chain. This is made possible by the overweight of photosystem II capacity in comparison to photosystem I activity as reported in this paper. Under the conditions described, the cyanobacterium grows also on ar­ginine as the sole nitrogen source. Most interestingly under these conditions nitrate reductase induction is not shut off as is the case with other aminoacids like ornithine or alanine in the medium. Nitrite reductase is not induced in these bacteria, if grown on arginine as the sole nitrogen source. This observation is discussed in context with the fact that arginine is a major storage product (cyanophycin) in this organism and that the observed photosystem II mediated H2O2-production might be correlated with arginine metabolism.

[Procedural guidelines. Good tissue practice for cornea banks]

A cornea bank must have an organizational structure in which responsibility and authority to issue directives are clearly defined. It must also use a documented quality management system on the basis of good practice procedures which is maintained to the current standards. The personnel of a cornea bank must be present in sufficient numbers and be suitably qualified. A cornea bank must be in possession of appropriate facilities which are suitable for the main purpose of conservation of donor corneas. All equipment must be designed and maintained corresponding to the intended purpose. Deviations from the stipulated quality and safety standards must give rise to documented investigations which include decisions on options for correctional and preventive measures. Acquisition of donors and tissue sampling must be strictly controlled and documented. This also applies to entry of donor tissue in the cornea bank. During conservation a microscopic examination of the endothelial cell layer must be carried out at least once. Measures must be taken to keep the risk of contamination as low as possible. Donor corneal tissue can only be released if defined criteria are fulfilled. Any suspicion of severe undesired reactions and events for the recipient of a corneal transplant must be registered with the authorities. The activities of a cornea bank must maintain and adapt the state-of-the-art with respect to scientific progress.

Esteraseaktivität eines organotypischen humanen Kornea-Konstrukts (HCC) als In-vitro-Modell für Permeationsuntersuchungen

Organotypic cornea equivalents are used as in vitro models for permeation studies. Many ophthalmic drugs are applied as ester prodrugs to achieve a higher bioavailability. The esterase activity of three corneal human cell lines (epithelial, stromal, endothelial cells) as well as of excised porcine cornea, human donor cornea and human cornea construct (HCC) was investigated and compared. Esterase activity was determined using p-nitrophenyl acetate and hydrocortisone acetate (HCA) as esterase substrates. Hydrocortisone acetate permeation across porcine cornea, human donor cornea and HCC was studied in vitro using Franz-diffusion cells. Corneal epithelial cells showed the highest esterase activity and only small differences to keratocytes and endothelial cells were detectable. The permeation barrier properties of the different corneal tissues were very similar in the case of HCA permeation whereas HCA metabolism rates were in the ranking order of porcine cornea > HCC > human donor cornea. Permeation and metabolism studies indicate that the in vitro permeation model HCC is able to adequately convert hydrocortisone acetate to hydrocortisone.

Human corneal equivalent as cell culture model for in vitro drug permeation studies

AIMS

For the study of transcorneal in vitro permeation of ophthalmic drugs, excised animal cornea or corneal epithelial cell culture are frequently used as a replacement for the human cornea. The main purposes of this study were to reconstruct a complete human organotypic cornea equivalent, consisting of all three different cell types (epithelial, stromal, and endothelial); to test the barrier function of this bio-engineered human cornea using three different model drugs (pilocarpine hydrochloride (PHCl), befunolol hydrochloride (BHCl), and hydrocortisone (HC)); and to determine its usefulness as an in vitro model for prediction of ocular drug absorption into the human eye.

METHODS

A multilayer tissue construct was created step by step in Transwell cell culture insert using SV-40 immortalised human endothelial and epithelial cells and native stromal cells (fibroblasts). Morphology was characterised by light microscopy using routine H&E staining. Scanning electron microscopy was used to evaluate ultrastructural features. Ocular permeation of drugs across the human cornea construct was tested using modified Franz cells and compared with data obtained from excised porcine cornea and previously described porcine cornea constructs.

RESULTS

and conclusion: The cornea construct exhibited typical corneal structures such as a monolayer of hexagonally shaped endothelial cells and a multilayered epithelium consisting of seven to nine cell layers with flat superficial cells. The formation of microplicae and microvilli was also confirmed. The human cornea construct showed similar permeation behaviour for all substances compared with excised porcine cornea. However, permeability (permeation coefficients K(p)) of the human cornea equivalent (PHCl 13.4*10(-6) (SD 3.01*10(-6)); BHCl 9.88*10(-6) (SD 1.79*10(-6)); HC 5.41*10(-6) (SD 0.40*10(-6)) cm/s) was about 1.6-1.8 fold higher than excised porcine cornea. Compared with data from the porcine cornea construct the cultivated human equivalent showed a decreased permeability. The reconstructed human cornea could be appropriate to predict drug absorption into the human eye.

Mechanisms of staurosporine induced apoptosis in a human corneal endothelial cell line

BACKGROUND

Apoptosis very probably plays a key part in endothelial cell loss during corneal storage in organ culture as well as hypothermic storage. However, the mechanisms underlying endothelial apoptosis are poorly understood. The response of a human corneal endothelial cell (HCEC) line to staurosporine, a known inducer of apoptosis, was investigated to gain insights into the intracellular modulators that participate in endothelial cell death.

METHODS

Immortalised HCECs were studied after 3, 6, 12, and 24 hours of incubation with 0.2 micro M staurosporine. Cell shedding was monitored. Hoechst 33342 fluorescent DNA staining combined with propidium iodide was used for apoptosis/necrosis quantification and morphological examination. The caspase-3 active form was assessed using western blot, proteolytic activity detection, and immunocytochemistry. The cleaved form of poly(ADP-ribose) polymerase (PARP) was assessed using immunocytochemistry and western blot. The ultrastructural features of cells were screened after 12 hours with staurosporine or vehicle.

RESULTS

The specific apoptotic nature of staurosporine induced HCEC death was confirmed. The ultrastructural features of staurosporine treated cells were typical of apoptosis. HCEC shedding and DNA condensation increased with time. Caspase-3 activity was detected as early as 3 hours after exposure with staurosporine, peaking at 12 hours of incubation. The presence of cleaved PARP after 3 hours confirmed caspase-3 activation.

CONCLUSIONS

These data suggest strongly that HCEC cell death induced by staurosporine is apoptosis. The main consequence of HCEC apoptosis is shedding. Staurosporine induced apoptosis of endothelial cells involves activation of caspase-3, and could be a useful model to study strategies of cell death inhibition.

Effect of three different media on serum free culture of donor corneas and isolated human corneal endothelial cells

BACKGROUND

Removal of bovine serum from organ culture medium is necessary because of the variability in serum composition and the potential risk of infection. Two specific endothelial cell media (F99 and Endothelial-SFM) were compared with the routinely used medium MEM for their use in serum free cultivation of human corneal endothelial cells (HCEC) and donor corneas.

METHODS

HCEC were incubated in three test media with or without increasing serum content and a growth assay was performed. Seven pairs of donor corneas were cultured in each of three media for 3 weeks, one cornea with serum supplementation and one without. Endothelial cell density was determined once each week. Trypan blue staining of the endothelium and vital staining of keratocytes was performed after 3 weeks.

RESULTS

All three media promoted proliferation of cultured HCEC when supplemented with serum. Endothelial cell density of donor corneas was comparable after 3 weeks of cultivation in the different media. Only corneas cultured in medium MEM without serum exhibited a higher endothelial cell loss. Trypan blue staining of the endothelium after cultivation revealed the lowest number of damaged cells on corneas cultured in the medium Endothelial-SFM. The highest densities of keratocytes were found in corneas cultured in Endothelial-SFM and the lowest densities occurred after culture in MEM.

CONCLUSION

After incubation in Endothelial-SFM even under serum free conditions corneas were found to be of higher quality with respect to endothelial cell survival, cell membrane integrity, and keratocyte density. This medium may replace MEM, which is routinely used in European eye banks but requires supplementation with serum.

Use of a serum-free medium for long-term storage of human corneas. Influence on endothelial cell density and corneal metabolism

BACKGROUND

The success of long-term corneal organ culture is limited by the progressive loss of endothelial cells during culture and the use of culture medium supplemented with fetal calf serum as a possible source of contamination with infectious agents. In this study, we investigated the suitability of a serum-free medium (Endothelial-SFM) to improve preservation conditions for human donor corneas.

METHODS

Six pairs of corneas were stored in Minimum Essential Medium (MEM) supplemented with 2% fetal calf serum (FCS) for 8-14 days. One cornea of each pair was then further cultivated in Endothelial-SFM supplemented with 2% FCS or in MEM with 2% FCS, respectively. In a second series of experiments, the endothelial cell density of seven pairs of freshly isolated donor corneas was determined during cultivation in Endothelial-SFM with 2% FCS or serum-free Endothelial-SFM.

RESULTS

After precultivation in conventional medium, the endothelial cell density of corneas allocated to cultivation in Endothelial-SFM was 1000-1950 cells/mm2 and that of those subsequently cultured in MEM 1200-2000 cells/mm2. At 9 weeks, cell densities of 900-1500 cells/mm2 were found after cultivation in Endothelial-SFM compared with a total cell loss in MEM. Freshly isolated corneas cultured in Endothelial-SFM with or without FCS supplementation showed a decrease of endothelial cell density of about 20% within the first 2 weeks of storage. During further cultivation cell density remained constant without statistically significant differences between the groups. Glucose consumption of the corneas was higher in Endothelial-SFM than in MEM. Corneas stored in Endothelial-SFM with 2% FCS showed a higher glucose consumption than those preserved in serum-free Endothelial-SFM.

CONCLUSION

Organ culture of human donor corneas using the serum-free basal medium Endothelial-SFM is superior to conventional culture conditions because the decrease in endothelial cell density can be ameliorated, the culture period can be prolonged and the risk of transmitting infectious agents via serum can be minimised.

Isolation and characterization of a mouse monoclonal antibody against human corneal endothelial cells

In vitro cultivation of human corneal endothelial cells (HCEC) is associated with loss of typical cobblestone-like appearance during successive passages. Thus far morphology was the sole criterion for the cell's endothelial nature. Mouse monoclonal antibodies (mabs) to human corneal endothelial cells were raised using standard immunization and hybridoma isolation procedures. The specificity of mabs for human corneal endothelial cells was tested in comparison to other endothelial cell types, to fibroblasts, corneal keratocytes and to human retinal pigmented epithelial cells. In addition immunofluorescence or immunoperoxidase staining was performed with frozen tissue sections of human corneas and with various other human tissues. The mab 9.3.E reacts with cultured human corneal endothelial cells, but not with cultured human fibroblasts and human keratocytes. In frozen sections selective positivity of corneal endothelium in contrast to negativity of the other corneal cell types was confirmed. In investigated extraocular tissues positivity was observed in smooth muscle cells including related cells (i.e. Ito and mesangial cells) and in Schwann's cells and adipocytes, but apparently not in vascular endothelial cells. The mab is human-specific and binds to a protein with a molecular weight of 130 kDa mainly accumulating along cell membranes. A mouse monoclonal antibody against human corneal endothelial cells was established in vitro and was shown to be capable of differentiating corneal endothelial cells from other corneal cell types, especially from corneal keratocytes. It is, however, not cornea-specific, but also reacts with certain extraocular cell types.

[Follow-up of endothelial cell density after perforating keratoplasty. Effect of donor and recipient-related factors]

PURPOSE

Endothelial cell loss can be observed after keratoplasty, therefore in a retrospective study we analysed whether there is a correlation between donor age, recipient age, time post-mortem, preoperative cell density, diagnosis of the recipient and postoperative endothelial cell density.

METHODS

The endothelial cell densities of 120 patients who had undergone penetrating keratoplasty were examined over a period of 2 years. We divided the patients into four groups based on the endothelial cell density over 2 years. We examined the groups with regard to the parameters given above.

RESULTS

The lowest postoperative cell densities 2 years after keratoplasty showed a high correlation with the highest donor and recipient age. Even the lowest preoperative cell density was found in this group. Patients who underwent keratoplasty because of keratoconus had the highest cell densities after 2 years and also the lowest donor and recipient age. The preoperative cell density was also highest in this group.

DISCUSSION

The results indicate a correlation between increasing donor and recipient age, decreasing preoperative cell density and loss of endothelial cells 2 years after penetrating keratoplasty. Patients with the diagnosis keratoconus should also receive transplants with higher donor age.

Effects of aging on left atrial reservoir, conduit, and booster pump function: a multi-institution acoustic quantification study

OBJECTIVE

To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function.

PATIENTS AND SETTING

165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres.

INTERVENTIONS

Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line.

MAIN OUTCOME MEASURES

Parameters of LA performance according to age and sex.

RESULTS

Signal averaged LA waveforms were sufficiently stable and detailed to allow automated analysis in all cases. An age related increase in LA area was noted. LA reservoir function did not vary with age or sex. All parameters of LA passive and active emptying revealed a significant age dependency. Overall, the passive emptying phase accounted for 66% of total LA emptying ranging from 76% in the youngest to 44% in the oldest decade. LA contraction accounted for 34% of atrial emptying in all subjects combined with the older subjects being more dependent on atrial booster pump function. When adjusted for atrial size, there were no sex related differences in LA function.

CONCLUSIONS

LA reservoir, conduit, and booster pump function can be assessed with automated analysis of signal averaged LA area waveforms. As LA performance varies with age, establishment of normal values should enhance the evaluation of pathologic states in which LA function is important.

Normal values of regional left ventricular endocardial motion: multicenter color kinesis study

Our goal was to establish normal values for quantitative color kinesis indexes of left ventricular (LV) wall motion over a wide range of ages, which are required for objective diagnosis of regional systolic and diastolic dysfunction. Color-encoded images were obtained in 194 normal subjects (95 males, 99 females, age 2 mo to 79 yr) in four standard views. Quantitative indexes of magnitude and timing of systolic and diastolic function were studied for age- and gender-related differences. Normal limits of all ejection and filling indexes were in a narrow range (< or =25% of the mean), with no major gender-related differences. Despite invariable ejection fractions, both peak filling and ejection rates decreased with age (30 and 20%, correspondingly) with a concomitant increase in mean filling and ejection times, resulting in five- and twofold increases in the late to early filling and ejection ratios, correspondingly. Diastolic asynchrony increased with age (from 4.7 +/- 2.0 to 6.4 +/- 3.2 from the 2nd to 7th decade). The normal values of color kinesis indexes should allow objective detection of regional LV systolic and diastolic dysfunction.

Recent developments in cornea transplantation (1997-1999)

Between 1997 and 1999 a steady increase in cornea donations was achieved, but the number of transplantations remained stable because many grafts did not pass quality control. Intermediate organ culture of entire bulbi was examined as a possible solution to reduce post-mortem times and increase suitability for transplantation.

Power Doppler imaging as a basis for automated endocardial border detection during left ventricular contrast enhancement

Echocardiographic evaluation of left ventricular (LV) systolic function relies on endocardial visualization, which can be improved when necessary using contrast enhancement. However, there is no method to automatically detect the endocardial boundary from contrast-enhanced images. We hypothesized that this could be achieved using harmonic power Doppler imaging. Twenty-two patients were studied in two protocols: (1) 11 patients with poorly visualized endocardium (> 3 contiguous segments not visualized) and (2) 11 consecutive patients referred for dobutamine stress echocardiography who were studied at rest and at peak dobutamine infusion. Patients were imaged in the apical four-chamber view using harmonic power Doppler mode (HP SONOS 5500) during LV contrast enhancement (Optison or Definity DMP115). Digital images were analyzed using custom software designed to automatically extract the endocardial boundary from power Doppler color overlays. LV cavity area was automatically measured frame-by-frame throughout the cardiac cycle, and fractional area change calculated and compared with those obtained by manually tracing the endocardial boundary in end-systolic and end-diastolic gray scale images. Successful border detection and tracking throughout the cardiac cycle was possible in 9 of 11 patients with poor endocardial definition and in 10 of 11 unselected patients undergoing dobutamine stress testing. Fractional area change obtained from power Doppler images correlated well with manually traced area changes (r = 0.82 and r = 0.97, in protocols 1 and 2, respectively). Harmonic power Doppler imaging with contrast may provide a simple method for semi-automated border detection and thus facilitate the objective evaluation of LV function both at rest and under conditions of stress testing. This methodology may prove to be particularly useful in patients with poorly visualized endocardium.

Immortalization of human corneal endothelial cells using electroporation protocol optimized for human corneal endothelial and human retinal pigment epithelial cells

PURPOSE

In this study we established a protocol for transfection of human corneal endothelial and human retinal pigment epithelial cells. This protocol was used for immortalization of human corneal endothelial cells.

METHODS

Transfection was performed by means of electroporation. For immortalization a plasmid encoding large and small SV40 T-antigen was used.

RESULTS

The established electroporation protocol was suitable for both cell types. This protocol was used for transfection of human corneal endothelial cells with a plasmid containing the early region of SV40. The transfected cultures exhibited an increased life-span before they entered crisis. One culture recovered from crisis and was cultivated for 300 population doublings. The cells exhibited an in vivo-like morphology usually lost during cell culture.

CONCLUSIONS

We describe for the first time a culture of SV40 transfected human corneal endothelial cells which recovered from crisis and can therefore be regarded as immortalized.

Effect of perfluorodecalin on human retinal pigment epithelium and human corneal endothelium in vitro

BACKGROUND

Perfluorocarbon liquids are useful intraoperative tools in complicated vitreoretinal surgery. They are usually removed at the end of the procedure, but small amounts may remain in the eye. Recently, contradictory results have been reported on the damage in association with residual perfluorocarbon liquids in the eye. This study examined the effects of perfluorodecalin on human retinal pigment epithelium and corneal endothelium in vitro.

METHODS

Vitality and proliferative capacity of cell cultures were measured after incubation with perfluorodecalin. Vitality of cell cultures were measured using the Life-Dead assay. Cell proliferation was determined by measuring incorporation of 5-bromo-2'-deoxyuridine into cellular DNA. Furthermore, endothelium of organ-cultured human corneas was examined after incubation with perfluorodecalin by photodocumentation.

RESULTS

Both cell types showed less extinctions in the Life-Dead assay after incubation with perfluorodecalin. After removing perfluorodecalin from the cultures, cells showed the same capacity of proliferation as the control cells. Compared to control corneas, perfluorodecalin induced a decrease in endothelial cell density. In four corneas, endothelial cell necrosis was observed.

CONCLUSION

Decreasing extinctions in the Life-Dead assay after incubation with perfluorodecalin can be interpreted as showing a decreasing amount of vital cells. Because cell proliferation showed no significant changes the results suggest that perfluorodecalin may not be directly toxic to cells in vitro. It may exert an indirect or mechanical effect on cell function by impeding the normal metabolic exchange between endothelium and medium. Based on these results perfluorodecalin should be completely removed after operation.

The role of echocardiographic harmonic imaging and contrast enhancement for improvement of endocardial border delineation

Despite advances in imaging technology, many myocardial segments remain poorly visualized with echocardiography; however, both contrast enhancement and harmonic imaging have shown promise for improving endocardial definition. Fifty subjects with technically limited echocardiograms were studied with fundamental and harmonic imaging as well as during echocardiographic contrast injection. Overall endocardial visualization scores improved with both techniques compared with fundamental imaging. Harmonic imaging improved endocardial visualization in 43% of all segments and in 57% of segments nonvisualized with fundamental imaging. The benefit of harmonic imaging was seen in all segments. Contrast echocardiography had similar overall improvements in visualization (42% of all segments, 67% of segments nonvisualized with fundamental imaging) but was not helpful in all regions. Harmonic imaging outperformed contrast in 9 of 22 segments, whereas contrast was superior in 4 of 22. In a subgroup of patients with very poor images, contrast enhancement was superior, with a greater increase in overall score and a higher salvage rate than harmonic (68% vs 40%).

Three-dimensional echocardiography in adult patients: comparison between transthoracic and transesophageal reconstructions

BACKGROUND

Three-dimensional (3D) echocardiography is a relatively new technique typically implemented with transesophageal imaging with multiplane transducers.

OBJECTIVES

The goals of this study were (1) to test the feasibility of 3D reconstruction with a new transthoracic multiplane transducer in adult subjects with excellent quality of 2-dimensional images and (2) to compare these reconstructions with those obtained in the same patients with the transesophageal approach.

METHODS

Transthoracic multiplane image acquisition was performed in 37 patients who were selected on the basis of the quality of their 2-dimensional images. In addition, transesophageal acquisition was also performed in 19 of 37 patients. Three-dimensional reconstruction of mitral and aortic valves was performed. Three-dimensional images were reviewed, and the visualization of various anatomic features was graded.

RESULTS

The reconstruction of 25 mitral valves and 16 aortic valves, normal and pathologic, was feasible and resulted in visualization of anatomic detail. Score indexes of all valvular characteristics studied were not significantly different when transthoracic and transesophageal reconstructions were compared.

CONCLUSIONS

Transthoracic 3D echocardiography with a multiplane transducer in adult patients with good acoustic windows is feasible. This technique will allow easy noninvasive serial assessment of valvular pathophysiologic characteristics.

Morphological and functional analysis of immortalized human corneal endothelial cells after transplantation

Approximately 50% of donor corneas are unsuitable for keratoplasty due to an unacceptably low endothelial cell count. One way of overcoming this problem and minimizing wastage of donor corneas may be to transplant cultured human corneal endothelial cells onto these. In this study, we examined the morphological characteristics and functional attributes of endothelial layers formed after the transplantation of immortalized cells in vitro. Cultured human corneal endothelial cells, immortalized by transfection with a plasmid encoding SV40 T-antigen, were seeded onto human corneas denuded of their own endothelium. Seven days after transplantation the newly established monolayers were examined by light, confocal and scanning electron microscopy. Endothelial pump function was gauged by monitoring changes in corneal thickness during perfusion of the endothelial face. The endothelia formed from transplanted immortalized cells had a cobblestone-like appearance, being composed of polygonal units joined by junctional complexes. The stromal hydration state of corneas bearing such endothelial layers could be controlled during perfusion. This was an active process achieved via the Na(+)/K(+)-ATPase-dependent endothelial pump, as demonstrated by inhibiting the enzyme with ouabain. Transplantation of immortalized human corneal endothelial cells onto recipient corneas led to the establishment of new monolayers which had the morphology of the native ones in organ-cultured corneas. This model provides us with a means of studying the formation and function of corneal endothelial layers in vitro.

[Endothelial cell transplantation and growth behavior of the human corneal endothelium]

BACKGROUND

The human corneal endothelium has a limited proliferative capacity in vivo. Until now it has only been possible to replace damaged endothelium by transplantation of a donor cornea. After establishing methods for the isolation and in vitro cultivation of human corneal endothelial cells, transplantation of these cells my be an alternative therapeutic option.

MATERIALS AND METHODS

In this review methods for the in vitro cultivation of human corneal endothelial cells and their transplantation on the Descemet membrane of donor corneas are described.

RESULTS

In vitro proliferation of human adult corneal endothelial cells was achieved by the development of defined cell culture conditions, including supplementation of culture medium with specified growth factors and substances. Dependent on the culture conditions, as well as independent of them, in vitro cultured endothelial cells showed phenotypic changes and different proliferative behavior. Thus, molecular biological examinations revealed a different expression pattern of growth factor receptors in fibroblast-like endothelial cells (dedifferentiated) compared to typical endothelial cells (differentiated). Moreover, the proliferative capacity of the cells differed, dependent on their corneal location. Cells isolated from the peripheral part of donor corneas have a higher proliferative capacity than cells obtained from the central part. The propagation of corneal endothelial cells in vitro offered the possibility of their transplantation on donor corneas in an in vitro model. After transplantation, these cells formed a monolayer whose morphology and cell density depended on the differentiation of the cells. DNA synthesis was predominantly detectable in cells of the corneal periphery.

CONCLUSIONS

Our findings are the basis of the following hypothesis: the periphery of the cornea represents a regenerative zone of the corneal endothelium. The fact that early after transplantation corneal endothelial cells form a monolayer on the natural extracellular matrix (ECM), which shows contact inhibition, suggests that inhibitory factors are released by the Descemet membrane that influence the proliferation of the cells. Further studies on the regulation of the proliferation and differentiation of human corneal endothelial cells in vitro and after transplantation might offer the possibility to establish a selective procedure for the treatment of corneal endothelial cell loss in the near future.

Objective evaluation of regional left ventricular wall motion during dobutamine stress echocardiographic studies using segmental analysis of color kinesis images

OBJECTIVES

To test the feasibility of objective and automated evaluation of echocardiographic stress tests, we studied the ability of segmental analysis of color kinesis (CK) images to detect dobutamine-induced wall motion abnormalities and compared this technique with inexperienced reviewers of conventional gray-scale images.

BACKGROUND

Conventional interpretation of stress echocardiographic studies is subjective and experience dependent.

METHODS

CK images were obtained in 89 of 104 consecutive patients undergoing clinical dobutamine stress studies and were analyzed using custom software to calculate regional fractional area change in 22 segments in four standard views. Each patient's data obtained at rest was used as a control for automated detection of dobutamine-induced wall motion abnormalities. Independently, studies were reviewed without CK overlays by two inexperienced readers who classified each segment's response to dobutamine. A consensus reading of two experienced reviewers was used as the gold standard for comparisons. In a subgroup of 16 patients, these consensus readings and CK detection of wall motion abnormalities were compared with coronary angiography.

RESULTS

The consensus reading detected ischemic response to dobutamine in 43 of 1958 segments in 23 of 89 patients. Automated detection of stress-induced wall motion abnormalities correlated more closely with the standard technique than the inexperienced reviewers (sensitivity 0.76 vs. 0.55, specificity 0.98 vs. 0.94 and accuracy 0.97 vs. 0.92). When compared with coronary angiography in a subgroup of patients, analysis of CK images differentiated between normal and abnormal wall motion more accurately than expert readers of gray-scale images (accuracy of 0.93 vs. 0.82).

CONCLUSIONS

Analysis of CK images allows fast, objective and automated evaluation of regional wall motion, sensitive enough for clinical dobutamine stress data and more accurate than inexperienced readers. This method may result in a valuable adjunct to conventional visual interpretation of dobutamine stress echocardiography.

Quantitative assessment of regional right ventricular function with color kinesis

We used color kinesis, a recent echocardiographic technique that provides regional information on the magnitude and timing of endocardial wall motion, to quantitatively assess regional right ventricular (RV) systolic and diastolic properties in 76 subjects who were divided into five groups, as follows: normal (n = 20), heart failure (n = 15), pressure/volume overload (n = 14), pressure overload (n = 12), and RV hypertrophy (n = 15). Quantitative segmental analysis of color kinesis images was used to obtain regional fractional area change (RFAC), which was displayed in the form of stacked histograms to determine patterns of endocardial wall motion. Time curves of integrated RFAC were used to objectively identify asynchrony of diastolic endocardial motion. When compared with normal subjects, patients with pressure overload or heart failure exhibited significantly decreased endocardial motion along the RV free wall. In the presence of mixed pressure/volume overload, the markedly increased ventricular septal motion compensated for decreased RV free wall motion. Diastolic endocardial wall motion was delayed in 17 of 72 segments (24%) in patients with RV pressure overload, and in 31 of 90 segments (34%) in patients with RV hypertrophy. Asynchrony of diastolic endocardial wall motion was greater in the latter group than in normal subjects (16% versus 10%: p < 0.01). Segmental analysis of color kinesis images allows quantitative assessment of regional RV systolic and diastolic properties.

Use of harmonic imaging without echocardiographic contrast to improve two-dimensional image quality

The aim of this study was to determine whether harmonic imaging (HI) improves endocardial visualization during 2-dimensional echocardiography without echocardiographic contrast. HI differs from fundamental imaging (FI) by transmitting ultrasound at one frequency and receiving at twice the transmitted frequency. This technique has been used in conjunction with contrast echocardiography to enhance myocardial contrast visualization. HI and FI were sequentially performed in 20 patients. Images were digitally stored and subsequently reviewed by 2 observers for the quality of endocardial visualization. In addition, acoustic quantification was performed in both FI and HI modes and endocardial tracking qualitatively judged. HI was compared with FI during dobutamine stress echocardiography in 17 patients who were imaged at baseline and peak stress. Overall, the harmonic images had less clutter and better myocardial blood contrast. Individual segments were better visualized with HI in 30% to 73% of cases. The acoustic quantification endocardial tracking was rated better with HI in 67% of short-axis views and in 58% of apical 4-chamber views. During dobutamine stress testing the overall number of interpretable segments improved from 64% for FI to 84% with HI. Many segments traditionally difficult to image were improved with HI. HI without the use of contrast agents improved endocardial visualization during routine 2-dimensional echocardiography. This improved endocardial visualization led to better endocardial tracking with acoustic quantification and to more segments being clinically interpretable during dobutamine stress testing.

Assessment of small-diameter aortic mechanical prostheses: physiological relevance of the Doppler gradient, utility of flow augmentation, and limitations of orifice area estimation

BACKGROUND

Noninvasive assessment of functionally stenotic small-diameter aortic mechanical prostheses is complicated by theoretical constraints relating to the hemodynamic relevance of Doppler-derived transprosthetic gradients. To establish the utility of Doppler echocardiography for evaluation of these valves, 20-mm Medtronic Hall and 19-mm St Jude prostheses were studied in vitro and in vivo.

METHODS AND RESULTS

Relations between the orifice transprosthetic gradient (equivalent to Doppler), the downstream gradient in the zone of recovered pressure (equivalent to catheter), and fluid mechanical energy losses were examined in vitro. Pressure-flow relations across the 2 prostheses were evaluated by Doppler echocardiography in vivo. For both types of prosthesis in vitro, the orifice was higher than the downstream gradient (P<0.001), and fluid mechanical energy losses were as strongly correlated with orifice as with downstream pressure gradients (r2=0.99 for both). Orifice and downstream gradients were higher and fluid mechanical energy losses were larger for the St Jude than the Medtronic Hall valve (all P<0.001). Whereas estimated effective orifice areas for the 2 valves in vivo were not significantly different, model-independent dynamic analysis of pressure-flow relations revealed higher gradients for the St Jude than the Medtronic Hall valve at a given flow rate (P<0.05).

CONCLUSIONS

Even in the presence of significant pressure recovery, the Doppler-derived gradient across small-diameter aortic mechanical prostheses does have hemodynamic relevance insofar as it reflects myocardial energy expenditure. Small differences in function between stenotic aortic mechanical prostheses, undetectable by conventional orifice area estimations, can be identified by dynamic Doppler echocardiographic analysis of pressure-flow relations.

Different characteristics of endothelial cells from central and peripheral human cornea in primary culture and after subculture

Several methods for isolation and cultivation of human corneal endothelial cells have been described during the last few decades. In contrast to the situation in vivo, the cultured cells show mitogenic activity but often lose their typical morphological appearance. In this paper, we describe a technique to isolate and cultivate morphologically unchanged endothelium from the human cornea. This method revealed different characteristics of endothelial cells according to their position within the human cornea. Endothelial cells isolated from the central part have a morphology similar to that of cells in vivo (i.e., they are densely packed and show no mitogenic activity). In contrast, endothelial cells derived from the peripheral part of the cornea are characterized by mitogenic activity but their cell-to-cell attachment seems to be less tight than in vivo. The significance of these two different endothelial cell types for wound healing in the human cornea is discussed.

Comparative study on the effects of different growth factors on migration of bovine corneal endothelial cells during wound healing

PURPOSE

In a comparative study we investigated the effects of epidermal growth factor, acidic and basic fibroblast growth factor, transforming growth factor-beta1, and vascular endothelial growth factor on proliferation and migration of cultured bovine corneal endothelial cells during wound healing.

METHODS

Cell proliferation was determined by incorporation of 5-bromo-2'-deoxy-uridine and by cell counting. To investigate cell migration, we established a method to produce identically shaped cell-free areas in monolayers of cultured cells and documented the wound-healing process.

RESULTS

Concerning the five tested growth factors, only epidermal growth factor as well as basic and acidic fibroblast growth factor stimulated DNA synthesis, cell proliferation, and migration during wound healing. Vascular endothelial growth factor stimulated migration during wound healing without influencing DNA synthesis or cell proliferation.

CONCLUSION

Whereas epidermal growth factor and the basic and acidic forms of fibroblast growth factor enhance proliferation as well as migration during wound healing, vascular endothelial growth factor seems to be a stimulatory agent specific for corneal endothelial cell migration.

Differences in proliferation and migration of corneal endothelial cells [correction of epithelial cells] after cell transplantation in vitro

For regular function the human cornea requires an intact endothelial cell layer with a sufficiently high cell density. One approach used to compensate endothelial cell loss is transplantation of cultured corneal endothelial cells. Using a previously described transplantation protocol, we observed topographic differences after transplantation of cultured human corneal endothelial cells to recipient corneas previously denuded of their own endothelium. The results presented in this paper suggest different interactions of the transplanted endothelial cells with the central or the peripheral part of the corneal matrix, respectively. Furthermore, cells isolated from the center of a human cornea differ from those isolated from the periphery in terms of their mitogenic capacity. The significance of these observations for corneal endothelial cell transplantation is discussed.

[Effect of differentiation on expression of genes for growth factors and growth factor receptors in human corneal endothelial cells]

In earlier publications we described a method for the isolation and long-term cultivation of human corneal endothelial cells. In several cultures we observed dedifferentiation of these cells, shown by loss of their normal polygonal shape and assumption of a fibroblastlike morphology. To reveal the role of growth factors for this dedifferentiation we analyzed the expression of genes encoding growth factors and growth factor receptors by differentiated and dedifferentiated human corneal endothelial cells. By means of northern blot analysis we demonstrated expression of the genes encoding basic fibroblast growth factor (bFGF), transforming growth factor beta (TGF beta 1), vascular endothelial growth factor (VEGF), FGF receptor-1 (flg-type) and epidermal growth factor receptor (EGF receptor) by both differentiated and dedifferentiated human corneal endothelial cells. In addition, expression of VEGF was stimulated by supplementation of growth medium by bFGF. In contrast, expression of the gene encoding flt-1, a receptor for VEGF, was only observed in dedifferentiated and not in differentiated human corneal endothelial cells. Despite this expression of flt-1, the dedifferentiated cells showed no mitogenic response to VEGF. The role of growth factors for dedifferentiation of human corneal endothelial cells is discussed.

Echocardiographic quantification of regional left ventricular wall motion with color kinesis

BACKGROUND

Color kinesis is a new technology for the echocardiographic assessment of left ventricular wall motion based on acoustic quantification. This technique automatically detects endocardial motion in real time by using integrated backscatter data to identify pixel transitions from blood to tissue during systole on a frame-by-frame basis. In this study, we evaluated the feasibility and accuracy of quantitative segmental analysis of color kinesis images to provide objective evaluation of regional systolic endocardial motion.

METHODS AND RESULTS

Two-dimensional echocardiograms were obtained in the short-axis and apical four-chamber views in 20 normal subjects and 40 patients with regional wall motion abnormalities. End-systolic color overlays superimposed on the gray scale images were obtained with color kinesis to color encode left ventricular endocardial motion throughout systole on a frame-by-frame basis. These color-encoded images were divided into segments by use of custom software. In each segment, pixels of different colors were counted and displayed as stacked histograms reflecting the magnitude and timing of regional endocardial excursion. In normal subjects, histograms were found to be highly consistent and reproducible. The patterns of contraction obtained in normal subjects were used as a reference for the objective automated interpretation of regional wall motion abnormalities, defined as deviations from this pattern. The variability in the echocardiographic interpretation of wall motion between two experienced readers was similar to the diagnostic variability between the consensus of the two readers and the automated interpretation.

CONCLUSIONS

Color kinesis is a promising new tool that may be used clinically to improve the qualitative and quantitative evaluation of spatial and temporal aspects of global and regional wall motion. In this initial study, segmental analysis of color kinesis images provided accurate, automated, and quantitative diagnosis of regional wall motion abnormalities.

Influence of vascular endothelial growth factor on bovine corneal endothelial cells in a wound-healing model

In this study we determined the influence of vascular endothelial growth factor (VEGF) on bovine corneal endothelial cell proliferation and wound healing. Proliferation was determined by measurement of DNA replication as well as by counting of the number of cells present after a defined growth period. In a wound-healing model, reproducible cell-free areas were created within monolayers of cultured bovine corneal endothelial cells and the migration of the cells into these areas was analyzed. The DNA replication and cell proliferation of bovine corneal endothelial cells were not influenced by VEGF. In contrast, in the wound-healing model, VEGF supplementation at concentrations of 1 and 10 ng/ml increased the cell density of the wounded area by 20% and 50%, respectively, as compared with the cell density of wounds left untreated by VEGF. Furthermore, no increase in DNA replication was found in cells involved in wound healing. Our results demonstrate that healing of bovine corneal endothelial cell layers after wounding is predominantly performed by cell migration rather than by proliferation. This migration can be stimulated by the addition of exogenous VEGF.