Practice differences and knowledge gaps in complex and high-risk interventions between Japan and the USA: A case-based discussion

Advances in percutaneous coronary intervention (PCI) devices and techniques have expanded the pool of eligible patients for revascularization, including those with comorbidities, reduced left ventricular function, or anatomical complexity (defined as CHIP: complex and high-risk interventions in indicated patients). CHIP interventions are typically performed by selected operators who specialize in complex PCI. This review presents two cases performed in the USA, to discuss the similarities and differences in practice patterns between CHIP operators in Japan and the USA. The first case involves a 58-year-old male presenting with myocardial infarction and cardiogenic shock, and the second case involves a 51-year-old female with a history of coronary artery bypass grafting presenting with a chronic total occlusion and PCI complicated by vessel perforation. The discussion focuses on appropriate patient selection, the role of the heart team approach for decision-making, the use of hemodynamic support devices, and other relevant factors. By comparing practices in Japan and the USA, this review highlights opportunities for knowledge exchange and potential areas for improving patient outcomes.

Impact of calcium on the procedural techniques and outcomes of chronic total occlusion percutaneous coronary intervention

BACKGROUND

Coronary calcification is common and increases the difficulty of chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We examined the impact of calcium on procedural outcomes of 13,079 CTO PCIs performed in 12,799 patients at 46 US and non-US centers between 2012 and 2023.

RESULTS

Moderate or severe calcification was present in 46.6% of CTO lesions. Patients whose lesions were calcified were older and more likely to have had prior coronary artery bypass graft surgery. Calcified lesions were more complex with higher J-CTO score (3.0 ± 1.1 vs. 1.9 ± 1.2; p < 0.001) and lower technical (83.0% vs. 89.9%; p < 0.001) and procedural (81.0% vs. 89.1%; p < 0.001) success rates compared with mildly calcified or non-calcified CTO lesions. The retrograde approach was more commonly used among cases with moderate/severe calcification (40.3% vs. 23.5%; p < 0.001). Balloon angioplasty (76.6%) was the most common lesion preparation technique for calcified lesions, followed by rotational atherectomy (7.3%), laser atherectomy (3.4%) and, intravascular lithotripsy (3.4%). The incidence of major adverse cardiovascular events (MACE) was higher in cases with moderate or severe calcification (3.0% vs. 1.2%; p < 0.001), as was the incidence of perforation (6.5% vs. 3.4%; p < 0.001). On multivariable analysis, the presence of moderate/severe calcification was independently associated with lower technical success (odds ratio, OR = 0.73, 95% CI: 0.63-0.84) and higher MACE (OR = 2.33, 95% CI: 1.66-3.27).

CONCLUSIONS

Moderate/severe calcification was present in nearly half of CTO lesions, and was associated with higher utilization of the retrograde approach, lower technical and procedural success rates, and higher incidence of in-hospital MACE.

Incidence, mechanisms, treatment, and outcomes of donor vessel injury during percutaneous coronary interventions for chronic total occlusion

BACKGROUND

Donor vessel injury is a potentially life-threatening complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

AIMS

Our goal was to examine the incidence, mechanisms, treatment, and outcomes of patients with donor vessel injury in a large multicenter CTO PCI registry.

METHODS

We analyzed the baseline clinical and angiographic characteristics, and procedural outcomes of 12,349 CTO PCIs performed between 2012 and 2022 at 44 centers.

RESULTS

The incidence of donor vessel injury was 0.35% (n = 43). The baseline clinical characteristics of patients with and without donor vessel injury were similar. Cases complicated by donor vessel injury were more complex with higher Japanese CTO score (2.9 ± 1.1 vs. 2.4 ± 1.3; p = 0.004) and lower procedural success rate (69.8% vs. 85.2%; p = 0.004). The retrograde approach was used more commonly in donor vessel injury cases (68.9% vs. 30.9%; p < 0.001). Most (53.5%) donor vessel injuries were guide catheter-induced, whereas 20.9% were due to donor vessel thrombosis. Of the 43 patients with donor vessel injury, 36 (83.7%) were treated with stenting and seven (16.3%) received a left ventricular assist device. The incidence of major adverse cardiovascular events (MACEs) was significantly higher in cases with donor vessel injury (23.3% vs. 2.0%; p < 0.001). Of the 43 patients with donor vessel injury, five patients (11.6%) experienced acute myocardial infarction and four patients (9.3%) died.

CONCLUSIONS

Donor vessel injury, occurred in 0.35% of CTO PCIs performed by experienced operators, was mainly due to guide catheter-induced dissection or thrombosis and was associated with lower procedural success and higher MACE.

Impact of target vessel on the procedural techniques and outcomes of chronic total occlusion percutaneous coronary intervention

BACKGROUND

There is limited information on the impact of the target vessel on the procedural techniques and outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We analyzed the baseline clinical and angiographic characteristics and procedural outcomes of 11,580 CTO PCIs performed between 2012 and 2022 at 44 centers.

RESULTS

The most common CTO target vessel was the right coronary artery (RCA) (53.1%) followed by the left anterior descending artery (LAD) (26.0%) and the left circumflex artery (LCX) (19.8%). RCA CTOs were longer and more complex, with a higher Japanese CTO score compared with LAD or LCX CTOs. Technical success was higher among LAD (88.8%) lesions when compared with RCA (85.7%) or LCX (85.8%) lesions (P less than .001). The incidence of major adverse cardiovascular events (MACE) was overall 1.9% (n = 220) and was similar among target vessels (P=.916). There was a tendency toward more frequent utilization of the retrograde approach for more proximal occlusions in all 3 target vessels. When compared with all other RCA lesions combined, distal RCA lesions had higher technical success (87.7% vs 85.3%; P=.048). Technical success was similar between various locations of LAD CTOs (P=.704). First/second/third obtuse marginal branch had lower technical success when compared with all other LCX lesion locations (82.7% vs 86.8%; P=.014). There was no association between MACE and CTO location in all 3 target vessels.

CONCLUSIONS

LAD CTO PCIs had higher technical and procedural success rates among target vessels. The incidence of MACE was similar among target vessels and among various locations within the target vessel.

Aortocoronary dissection during percutaneous coronary interventions for chronic total occlusion: Insights from the PROGRESS-CTO registry

BACKGROUND

Aortocoronary dissection is a potentially serious complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI).

METHODS

We examined the incidence, mechanisms, treatment, and outcomes of aortocoronary dissection among 12,117 CTO PCIs performed between 2012 and 2022 in a large multicenter CTO PCI registry.

RESULTS

The incidence of aortocoronary dissection was 0.2% (n = 27). Most aortocoronary dissections occurred in the right coronary artery (96.3%, n = 26). The baseline clinical characteristics of patients with and without aortocoronary dissection were similar, except for dyslipidemia, which was less common in patients with aortocoronary dissection (70.4% vs. 86.0%; p = 0.019). The retrograde approach was used more commonly among cases complicated by aortocoronary dissection (59.3% vs. 31.0%; p = 0.002). Technical (74.1% vs. 86.6%; p = 0.049) and procedural (70.4% vs. 85.2%; p = 0.031) success rates were lower among aortocoronary dissection cases, with a similar incidence of in-hospital major adverse cardiovascular events (3.7% vs. 2.0%; p = 0.541). Of the 27 patients with aortocoronary dissection, 19 (70.4%) were treated with ostial stenting and 8 (29.6%) were treated conservatively without subsequent adverse clinical outcomes. No patients required emergency surgery. Follow-up was available for 22 patients (81.5%): during a mean follow up of 767 (±562) days, the incidence of in-stent restenosis was 11.1% (n = 3).

CONCLUSIONS

Aortocoronary dissection occurred in 0.2% of CTO PCIs performed by experienced operators, was associated with lower technical and procedural success, and was treated most commonly with ostial stenting. None of the patients required emergency cardiac surgery.

Body Mass Index and Chronic Total Occlusion Percutaneous Coronary Intervention Outcomes: Is Overweight the New Normal?

BACKGROUND

Although high body mass index (BMI) is a known risk factor for the development of cardiovascular diseases, people who are overweight or obese often have better outcomes after cardiac procedures. Whether this "obesity paradox" is observed in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is unknown. Therefore, we examined the association of BMI with the outcomes of CTO-PCI in patients from the large, multicenter PROGRESS-CTO registry after stratifying patients into 3 BMI groups.

Chronic Total Occlusion Interventions in Patients with Reduced Ejection Fraction

PURPOSE OF THE REVIEW

The goal of this paper is to review the current evidence surrounding CTO PCI in patients with low EF, the most high-risk population to treat. We also present pertinent case examples and offer practical tips to increase success and lower complications when performing CTO PCI in patients with low EF.

RECENT FINDINGS

In a prospective randomized control study, greater improvement in angina frequency and quality of life, assessed by the Seattle Angina Questionnaire, was achieved by CTO PCI compared to optimal medical therapy. Furthermore, after successful CTO PCI, improvements in health status were similar in patients with both low and normal EF. CTO PCI can not only ameliorate symptoms of angina in patients with low EF but may also potentially improve EF in carefully selected populations. However, information regarding treatment of this high-risk population is lacking and large-scale studies targeting patients with severely reduced EF remain necessary.

Development and validation of a scoring system for predicting clinical coronary artery perforation during percutaneous coronary intervention of chronic total occlusions: the PROGRESS-CTO perforation score

BACKGROUND

Coronary artery perforation is a feared complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and often leads to serious adverse clinical events.

AIMS

We sought to develop a risk score to predict clinical coronary artery perforation in patients undergoing CTO PCI.

METHODS

We analysed clinical and angiographic parameters from 9,618 CTO PCIs in the Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO). Logistic regression prediction modelling was used to identify variables independently associated with clinical perforation, and the model was internally validated with bootstrapping. Clinical coronary artery perforation was defined as any perforation requiring treatment.

RESULTS

The incidence of clinical coronary perforation was 3.8% (n=367). Five factors were independently associated with perforation and were included in the score: patient age ≥65 years +1 point (odds ratio [OR] 1.79, 95% confidence interval [CI]: 1.37-2.33), moderate/severe calcification +1 point (OR 1.85, 95% CI: 1.41-2.42), blunt/no stump +1 point (OR 1.45, 95% CI: 1.10-1.92), use of antegrade dissection and re-entry +1 point (OR 2.43, 95% CI: 1.61-3.69), and use of the retrograde approach +2 points (OR 4.02, 95% CI: 2.95-5.46). The resulting score showed acceptable performance on receiver operating characteristic (ROC) curve (area under the curve [AUC]: 0.741, 95% CI: 0.712-0.773). The Hosmer-Lemeshow test indicated a good fit (p=0.991), and internal validation with bootstrapping demonstrated good agreement with the model with observed AUC: 0.736 (95% bias-corrected CI: 0.706-0.767).

CONCLUSIONS

The PROGRESS-CTO perforation score may be a useful tool for predicting clinical coronary perforation during CTO PCI.

Saphenous Vein Graft Occlusion Following Native Vessel Chronic Total Occlusion Percutaneous Coronary Intervention

BACKGROUND

Whether saphenous vein grafts (SVGs) should be occluded after successful chronic total occlusion (CTO) percutaneous coronary intervention (PCI) of the corresponding native vessel remains controversial.

METHODS

We analyzed the clinical and angiographic characteristics and procedural outcomes of 51 patients who underwent SVG occlusion following successful CTO-PCI of the corresponding native vessel between 2015 and 2022 at 14 centers.

RESULTS

Mean patient age was 71 ± 8 years and 80% were men. The most common CTO target vessel was the right coronary artery (41%), followed by the left circumflex (37%). Retrograde crossing through the SVG was the successful crossing strategy in 40 cases (78%). SVG occlusion was achieved with coils (1.9 ± 1.0) in 35 of 51 patients (69%) and vascular plugs in the other 16 cases (31%). All procedures were technically successful and the SVG was occluded completely (TIMI 0 flow) in 38 of the cases (75%), with the remaining cases having TIMI 1 flow. Follow-up was available for 37 patients (73%); during a mean follow-up of 312 days from CTO-PCI, the incidence of target-lesion failure due to restenosis was 5.4% (n = 2) with no other major events reported.

CONCLUSION

Following native vessel CTO-PCI, SVG occlusion is often performed and is associated with favorable mid-term outcomes.

Incidence, Mechanisms, Treatment, and Outcomes of Coronary Artery Perforation During Chronic Total Occlusion Percutaneous Coronary Intervention

Coronary artery perforation is a feared complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Our objective was to describe the incidence, mechanisms, treatment, and outcomes of coronary artery perforation during CTO PCI. We analyzed the baseline clinical and angiographic characteristics and procedural outcomes of 10,454 CTO PCIs performed in 10,219 patients between 2012 and 2022. The incidence of coronary perforation was 4.9% (n = 503). Patients who experienced coronary perforation were older and were more likely to have had previous coronary artery bypass graft surgery. Procedures that resulted in perforation were more complex, with higher Japanese CTO and Prospective Global Registry for the Study of Chronic Total Occlusion Intervention (PROGRESS-CTO) scores. Technical (66% vs 87%, p <0.001) and procedural (55% vs 87%, p <0.001) success rates were lower in perforation cases. The CTO target vessel was the most common perforation site (66%). The retrograde approach was responsible for the perforation in 47% of cases, and guidewire exit was the most common perforation mechanism. The proportion of Ellis class 1, 2, 3, and 3 -"cavity spilling" coronary perforations was 20%, 41%, 28%, and 11%, respectively. In 52% of perforations, 1 or more interventions were required: prolonged balloon inflation (23%), covered stent deployment (21%), coil embolization (6%), and/or autologous fat embolization (4%). Tamponade requiring pericardiocentesis occurred in 69 patients (14%). The incidence of major adverse cardiovascular events was higher in perforation cases (18% vs 1.3%, p <0.001). In conclusion, coronary artery perforation occurred in 4.9% of CTO PCIs performed by experienced operators and was associated with lower technical success and higher in-hospital major adverse cardiovascular events.

Intravascular lithotripsy in chronic total occlusion percutaneous coronary intervention: Insights from the PROGRESS-CTO registry

BACKGROUND

The use of intravascular lithotripsy (IVL) in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has received limited study.

METHODS

We analyzed the baseline clinical and angiographic characteristics and procedural outcomes of 82 CTO PCIs that required IVL at 14 centers between 2020 and 2022.

RESULTS

During the study period, IVL was used in 82 of 3301 (2.5%) CTO PCI procedures (0.4% in 2020 and 7% in 2022; p for trend < 0.001). Mean patient age was 69 ± 11 years and 79% were men. The prevalence of hypertension (95%), diabetes mellitus (62%), and prior PCI (61%) was high. The most common target vessel was the right coronary artery (54%), followed by the left circumflex (23%). The mean J-CTO and PROGRESS-CTO scores were 2.8 ± 1.1 and 1.3 ± 1.0, respectively. Antegrade wiring was the final successful crossing strategy in 65% and the retrograde approach was used in 22%. IVL was used in 10% of all heavily calcified lesions and 11% of all balloon undilatable lesions. The 3.5 mm lithotripsy balloon was the most commonly used balloon (28%). The mean number of pulses per lithotripsy run was 33 ± 32 and the median duration of lithotripsy was 80  (interquartile range: 40-103) seconds. Technical and procedural success was achieved in 77 (94%) and 74 (90%) cases, respectively. Two (2.4%) Ellis Class 2 perforations occurred after IVL use and were managed conservatively.

CONCLUSION

IVL is increasingly being used in CTO PCI with encouraging outcomes.

Patient and Device Selection for Hemodynamic Support in High-Risk Percutaneous Coronary Intervention

Coronary artery disease continues to advance resulting in the development of high-risk percutaneous interventions. This includes treatment of patients with multivessel disease, unprotected left main, acute myocardial infarction complicated by cardiogenic shock, and depressed left ventricular ejection fraction. As a result, mechanical circulatory support devices have evolved but require an understanding of patient hemodynamics, device mechanics, and access management. Trial data regarding device selection are limited by inclusion of cardiogenic shock patients, and observational studies are conflicted by selection bias, site familiarity with devices, and complication management; therefore, clinical judgment is required to treat high-risk patients appropriately.

A Novel Hybrid Approach to the Treatment of a Left Main Coronary Artery Aneurysm

A 66-year-old man with a ramus chronic total occlusion had escalating angina and a high-risk stress test. Coronary angiography the day of his planned ramus chronic total occlusion percutaneous coronary intervention demonstrated a large left main aneurysm. He underwent bypass with left internal mammary artery left anterior descending and failed saphenous vein graft ramus, followed by successful covered stent placement from left main into left circumflex and ramus chronic total occlusion percutaneous coronary intervention. (Level of Difficulty: Advanced.)

RadialFirst in CHIP and Cardiogenic Shock

This article highlights the advantages and disadvantages of transradial arterial (TRA) access for a variety of presentations including acute coronary syndromes; cardiogenic shock; unprotected left main, heavily calcified coronaries; bifurcations; and chronic total occlusions. It includes techniques for overcoming challenges of using TRA access, including spasm and the need for larger bore guides. In addition, the authors review the use of ultrasound for access, percutaneous hemodynamic support via axillary approach, and tips and tricks to performing right heart catheterizations from the antecubital vein.

Percutaneous Coronary Intervention: Developments in the Last 12 Months

In 2018, there were several studies that significantly added to the field of interventional cardiology. Research was focused on understanding the role of percutaneous coronary intervention (PCI) in various clinical syndromes, optimizing outcomes for high-risk lesion subsets, and building an evidence base for greater adoption of PCI guided by physiology and intracoronary imaging. In the area of innovation, novel and iterative developments in drug-eluting stents (DES) and scaffold platforms were compared with current generation DES. This article summarizes the research from last year which has had the most impact on PCI techniques and clinical care.

Dorsal (Distal) Transradial Access for Coronary Angiography and Intervention

Access to the arterial system through the distal or dorsal terminal end of the radial artery has recently been developed for interventional and diagnostic procedures. This technique may offer some advantages for specific patient subsets over the traditional radial approach. It may also offer advantages to the operator especially when using the left radial artery. The approach to successful dorsal radial access is described along with hemostasis. Although significant adverse events have not been described in the literature or on social media, several potential areas for vigilance are mentioned.

Controversies in complex percutaneous coronary intervention: radial versus femoral

INTRODUCTION

Evolution in the technology used in the cardiac catheterization laboratory has permitted a migration from the femoral to radial artery access for many interventional procedures while concurrently improving outcomes. As a disruptive technology, transradial access has been associated with several controversies including a dichotomous relationship with femoral access. Areas covered: Several different patient subsets along with perceived technical challenges in interventional cardiology are reviewed with regard to the issue of access site. Evolving technological improvements germane to transradial techniques are also discussed as garnered from the literature of recent clinical trials and reports. Expert commentary: Radial techniques have been enhanced by newer technology and the spread of knowledge. Fusion of radial techniques with those of the femoral approach is evolving into a unifying concept of using the access that is most appropriate for the patient. No one access technique can cover all clinical subsets of patients. There is a need for complimentary access skillsets for even the most advanced cardiovascular technology used in the cardiac catheterization laboratory if the patients' outcomes are to be idealized.

Influence of long-term oxygen therapy on cardiac acceleration and deceleration capacity in hypoxic patients with chronic obstructive pulmonary disease

BACKGROUND

There is increasing interest in cardiovascular co-morbidities of chronic obstructive pulmonary disease (COPD). Heart rate turbulence (HRT) and phase-rectified signal averaging (PRSA) techniques quantify the heart's acceleration/deceleration capacities. We postulated that these methods can help assess the integrity of cardiac control in hypoxic COPD.

METHODS

Eight hypoxic stable COPD patients, nine healthy age-matched older adults and eight healthy young adults underwent ECG monitoring for 24 h. Patients with COPD were also monitored following 4 weeks of standardized oxygen therapy. HRT measures [turbulence onset (TO), turbulence slope (TS)] and PRSA-derived acceleration/deceleration (AC, DC) indices were quantified within 6-h blocks to assess circadian variation.

RESULTS

There were between-group differences for variables TS, DC and AC (P<0·0005, η(2) = 0·54-0·65), attributable solely to differences between healthy young and COPD subjects. Only HR (P<0·0005) and DC index (P = 0·008) showed circadian variation. A significant interaction 'trend' effect for HR (F(9,87) = 2·52, P = 0·015, η(2) = 0·21) reflected the strong influence of COPD on HR circadian variation (afternoon and night values being different to those in healthy subjects).

CONCLUSIONS

As expected, heart rate dynamics were substantially diminished in older (healthy and COPD) groups compared with healthy young controls. Patients with COPD showed similar heart rate dynamics compared with age-matched controls, both before and after hypoxia correction. However, there was a suggestion of diminished DC in COPD compared with age-matched controls (P = 0·059) that was absent following oxygen therapy. TS, DC and AC indices were altered by similar degrees in older subjects, apparently indicating equivalent tonic dysfunction of sympathetic/parasympathetic systems with ageing.

Neurodegenerative actions of interleukin-1 in the rat brain are mediated through increases in seizure activity

The cytokine interleukin-1 (IL-1) is an established and important mediator of diverse forms of neuronal injury in experimental animals. However, its mechanisms of action remain largely unknown. We have reported previously that IL-1 markedly enhances excitotoxic injury induced in the rat by striatal administration of the excitotoxin alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA), leading to widespread neuronal loss throughout the ipsilateral cortex. Here we tested the hypothesis that IL-1 causes this injury through induction and/or enhancement of seizure activity in the rat. Consistently with this hypothesis, intrastriatal injection of AMPA or AMPA with IL-1 in the rat brain increased c-Fos expression in regions similar to those in which c-Fos has been reported previously in response to seizures. A significant increase in cortical neuronal activity (number of c-Fos positive cells) was observed in response to AMPA with IL-1 compared with AMPA (8 hr after injection). Increased seizure duration [3,522 +/- 660 sec (SEM) vs. 1,415 +/- 301 sec; P < 0.001] and cell death volume (140 +/- 20 mm3 vs. 52 +/- 6 mm3; P < 0.001) were seen in response to coinfusion of AMPA with IL-1 vs. AMPA alone. In addition, the anticonvulsant diazepam (intraperitoneal) significantly reduced cell death (P < 0.001) and seizure duration (P < 0.001) induced by AMPA with IL-1, and a significant correlation was found between seizure duration and cell death volume. These findings support our hypothesis that IL-1 enhances excitotoxic injury by enhancement of seizures, which may be of relevance to IL-1 actions in other forms of neuronal injury, including cerebral ischemia.

The Diana community nursing team and paediatric palliative care

This article describes the work of the Diana community nursing teams, a new nurse-led service funded by the Department of Health (DoH) to commemorate the life and work of Diana, Princess of Wales. It identifies paediatric palliative care as an emerging specialty within children's nursing and discusses how children and young people with life-limiting/threatening conditions and their families may benefit from this new service. It is anticipated that the Diana teams will work with existing services such as children's hospitals, outreach services, children's hospices, social services and education and voluntary agencies. A key element of this service will be the ability of Diana team members to work across professional and organizational boundaries to provide a seamless care service and promote the concept of 'joined-up working' (Hyman, 1998). Education in this specialty, preferably multidisciplinary education, is needed so that healthcare professionals in this field can share knowledge, skills and research findings and deliver up-to-date care based on clinical effectiveness.

A selective Pt-CdS photodiode to monitor erythemal flux

The design and potential benefit of a solar ultraviolet (UV) radiometer reporting a maximum instantaneous flux of erythemally weighted heterogeneous energy is considered. The proposed device is electronically peak detecting; the user would ideally 'point and paint' the sun to find a localized maximum. A projected exposure time can be calculated from an instantaneous reading of erythemally weighted flux for a given minimal erythemal dose (MED) specified by the user. This calculation, though not necessarily providing a true exposure time, may be useful and informative in that it serves as a more 'recognizable' measure of erythemal flux and introduces a custom scale for each individual via their MED. Erythemal flux is calculated as the weighted integral sum [symbol: see text]j(lambda,t) epsilon(lambda) d lambda, where j (lambda, t) is the instantaneous angular integrated spectral irradiance accepted by human skin. This instrument proposal uses a single interference filter over a Pt-CdS photodiode; the interference filter is offered as a nominal design transmittance. The simulated response of the selective photodiode has a near-linear relation to the effective irradiance. Test inputs for evaluation purposes and to elucidate a transducer response are constructed from a spline interpolation of the World Radiation Center (WRC) spectrum and classic transmittance models. Our desired erythemal flux is offered in interconvertible UV Indexes (UVIs) as a function of zenith angle and atmosphere, characterized by elevation, ozone path, and turbidity.

A comparison of the effects of capsaicin with inhibitory nerve stimulation in the rat anococcygeus muscle in vitro

Capsaicin was used to test whether centrifugal activation of sensory fibres in the rat anococcygeus muscle can contribute to non-adrenergic non-cholinergic (NANC) relaxation of the muscle. In a solution containing 0.5 mM Ca2+ and in the presence of carbachol (10 microM) capsaicin evoked a fast concentration-dependent relaxation of the muscle that was usually followed by a smaller, slower, relaxant response. The fast relaxant response was reduced when extracellular Ca2+ was raised to 2.5 mM, desensitized after a single application of capsaicin and was blocked by tetrodotoxin (1 microM) or ruthenium red (10 microM). The fast response was greatly reduced by haemoglobin, by cold storage of the muscles or by N-monomethyl-L-arginine (100 microM) in the absence but not in the presence of L-arginine (100 microM). It is concluded that centrifugal activation of sensory fibres evokes a nitric oxide-mediated relaxation of the anococcygeus muscles that probably contributes to electrically evoked NANC relaxation.

Wavelength dependence of skin cancer induction by ultraviolet irradiation of albino hairless mice

Information on the variation in carcinogenicity with wavelength is crucial in risk assessments for skin cancers induced by UV radiation. Until recently the wavelength (lambda) dependencies of other detrimental UV effects, such as sunburn, have been used as substitutes. Direct information on the lambda dependency can only be obtained from animal experiments. To this end we accumulated a large data set on skin tumors induced by chronic UV exposure of albino SKH:HR1 mice (14 different broadband UV sources and about 1100 mice); the data come from the Photobiology Unit of the former Skin and Cancer Hospital in Philadelphia and from the Department of Dermatology of the University of Utrecht. The lambda dependency was extracted from this data set (a statistically satisfactory description with chi 2 = 13.4, df = 7) and represented by the Skin Cancer Utrecht-Philadelphia action spectrum, i.e., a set of factors to weight the exposures at different wavelengths according to their respective effectiveness (inversely proportional to the daily exposure required for a median tumor induction time of 300 days). The fits obtained with other already available action spectra proved to be poor (chi 2 > 60, df = 11). The maximum effectiveness was found at 293 nm, and above 340 nm the effectiveness showed a shoulder at about 10(-4) of the maximum. A sensitivity analysis of the final solution for the lambda dependency showed a large margin of uncertainty above 340 nm and an information gap below 280 nm. The large variation in tumor responses in the present data set can be transformed to a coherent, common dose-response relationship by proper spectral weighting with this single action spectrum.

All the observed universe has contributed to life

This paper presents evidence that virtually all electrons and nuclei of the atoms that are or have been part of living matter on Earth came from almost all stars in our and nearby galaxies and even from all other galaxies in the Universe that have produced observed high-energy gamma rays. However, a standard 70 kg human is always making about 7 3He, 600 40Ca, and 3000 14N nuclei every second by radioactive decay of 3H, 40K, and 14C, respectively.

Breath-by-breath measurement of oxygen consumption and FIO2-FEO2 with increased oxygen demand

Continuous on-line breath-by-breath measurement of pulmonary gas exchange was used to monitor the increase in oxygen uptake (VO2) and carbon dioxide excretion (VCO2) induced by the oxidative phosphorylation uncoupling agent 2, 4-dinitrophenol (DNP) in 10 dogs. With incremental doses of DNP totaling 5 mg/kg, the continuously monitored VO2 increased within 2-3 min after the first injection of the drug. VCO2 showed a similar response 4-6 min after the first injection. Temperature increase due to the pharmacological oxidative phosphorylation uncoupling required 20-30 min for a discernible change at this dose. This study also demonstrated a modified and compromised response to the drug in dogs where oxygen delivery was limited by mechanical ventilation.