El Niño-Southern Oscillation forcing on carbon and water cycling in a Bornean tropical rainforest

Carbon dioxide and water vapor exchanges between tropical forest canopies and the atmosphere through photosynthesis, respiration, and evapotranspiration (ET) influence carbon and water cycling at the regional and global scales. Their inter- and intra-annual variations are sensitive to seasonal rhythms and longer-timescale tropical climatic events. In the present study, we assessed the El Niño-Southern Oscillation (ENSO) influence on ET and on the net ecosystem exchange (NEE), using eddy-covariance flux observations in a Bornean rainforest over a 10-y period (2010-2019) that included several El Niño and La Niña events. From flux model inversions, we inferred ecophysiological properties, notably the canopy stomatal conductance and "big-leaf" maximum carboxylation rate (Vcmax25_BL). Mean ET values were similar between ENSO phases (El Niño, La Niña, and neutral conditions). Conversely, the mean net ecosystem productivity was highest during La Niña events and lowest during El Niño events. Combining Shapley additive explanation calculations for nine controlling factors with a machine-learning algorithm, we determined that the primary factors for ET and NEE in the La Niña and neutral phases were incoming shortwave solar radiation and Vcmax25_BL, respectively, but that canopy stomatal conductance was the most significant factor for both ET and NEE in the El Niño phase. A combined stomatal-photosynthesis model approach further indicated that Vcmax25_BL differences between ENSO phases were the most significant controlling factor for canopy photosynthesis, emphasizing the strong need to account for ENSO-induced ecophysiological factor variations in model projections of the long-term carbon balance in Southeast Asian tropical rainforests.

Carbon uptake in Eurasian boreal forests dominates the high-latitude net ecosystem carbon budget

Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003-2015) vegetation gross primary productivity (GPP), ecosystem respiration (R_eco ), net ecosystem CO₂ exchange (NEE; R_eco  - GPP), and terrestrial methane (CH₄ ) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites. We used TCFM-Arctic to obtain daily 1-km² flux estimates and annual carbon budgets for the pan-Arctic-boreal region. Across the domain, the model indicated an overall average NEE sink of -850 Tg CO₂ -C year^-1 . Eurasian boreal zones, especially those in Siberia, contributed to a majority of the net sink. In contrast, the tundra biome was relatively carbon neutral (ranging from small sink to source). Regional CH₄ emissions from tundra and boreal wetlands (not accounting for aquatic CH₄ ) were estimated at 35 Tg CH₄ -C year^-1 . Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high-latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change.

Modeled production, oxidation, and transport processes of wetland methane emissions in temperate, boreal, and Arctic regions

Wetlands are the largest natural source of methane (CH₄ ) to the atmosphere. The eddy covariance method provides robust measurements of net ecosystem exchange of CH₄ , but interpreting its spatiotemporal variations is challenging due to the co-occurrence of CH₄ production, oxidation, and transport dynamics. Here, we estimate these three processes using a data-model fusion approach across 25 wetlands in temperate, boreal, and Arctic regions. Our data-constrained model-iPEACE-reasonably reproduced CH₄ emissions at 19 of the 25 sites with normalized root mean square error of 0.59, correlation coefficient of 0.82, and normalized standard deviation of 0.87. Among the three processes, CH₄ production appeared to be the most important process, followed by oxidation in explaining inter-site variations in CH₄ emissions. Based on a sensitivity analysis, CH₄ emissions were generally more sensitive to decreased water table than to increased gross primary productivity or soil temperature. For periods with leaf area index (LAI) of ≥20% of its annual peak, plant-mediated transport appeared to be the major pathway for CH₄ transport. Contributions from ebullition and diffusion were relatively high during low LAI (<20%) periods. The lag time between CH₄ production and CH₄ emissions tended to be short in fen sites (3 ± 2 days) and long in bog sites (13 ± 10 days). Based on a principal component analysis, we found that parameters for CH₄ production, plant-mediated transport, and diffusion through water explained 77% of the variance in the parameters across the 19 sites, highlighting the importance of these parameters for predicting wetland CH₄ emissions across biomes. These processes and associated parameters for CH₄ emissions among and within the wetlands provide useful insights for interpreting observed net CH₄ fluxes, estimating sensitivities to biophysical variables, and modeling global CH₄ fluxes.

Vegetation type is an important predictor of the arctic summer land surface energy budget

Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994-2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm^-2) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.

A decade of CO2 flux measured by the eddy covariance method including the COVID-19 pandemic period in an urban center in Sakai, Japan

Cities constitute an important source of greenhouse gases, but few results originating from long-term, direct CO₂ emission monitoring efforts have been reported. In this study, CO₂ emissions were quasi-continuously measured in an urban center in Sakai, Osaka, Japan by the eddy covariance method from 2010 to 2021. Long-term CO₂ emissions reached 22.2 ± 2.0 kg CO₂ m^-2 yr^-1 from 2010 to 2019 (± denotes the standard deviation) in the western sector from the tower representing the densely built-up area. Throughout the decade, the annual CO₂ emissions remained stable. According to an emission inventory, traffic emissions represented the major source of CO₂ emissions within the flux footprint. The interannual variations in the annual CO₂ flux were positively correlated with the mean annual traffic counts at two highway entrances and exits. The CO₂ emissions decreased suddenly, by 32% ± 3.1%, in April and May 2020 during the period in which the first state of emergency associated with COVID-19 was declared. The annual CO₂ emissions also decreased by 25% ± 3.1% in 2020. Direct long-term observations of CO₂ emissions comprise a useful tool to monitor future emission reductions and sudden disruptions in emissions, such as those beginning in 2020 during the COVID-19 pandemic.

Cross-biome synthesis of source versus sink limits to tree growth

Uncertainties surrounding tree carbon allocation to growth are a major limitation to projections of forest carbon sequestration and response to climate change. The prevalence and extent to which carbon assimilation (source) or cambial activity (sink) mediate wood production are fundamentally important and remain elusive. We quantified source-sink relations across biomes by combining eddy-covariance gross primary production with extensive on-site and regional tree ring observations. We found widespread temporal decoupling between carbon assimilation and tree growth, underpinned by contrasting climatic sensitivities of these two processes. Substantial differences in assimilation-growth decoupling between angiosperms and gymnosperms were determined, as well as stronger decoupling with canopy closure, aridity, and decreasing temperatures. Our results reveal pervasive sink control over tree growth that is likely to be increasingly prominent under global climate change.

Global maps of soil temperature

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1-km2 resolution for 0-5 and 5-15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1-km2 pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse-grained air temperature estimates from ERA5-Land (an atmospheric reanalysis by the European Centre for Medium-Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (-0.7 ± 2.3°C). The observed substantial and biome-specific offsets emphasize that the projected impacts of climate and climate change on near-surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil-related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.

Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties

The regional variability in tundra and boreal carbon dioxide (CO₂ ) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO₂ fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO₂ fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990-2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO₂ fluxes and test the accuracy and uncertainty of different statistical models. CO₂ fluxes were upscaled at relatively high spatial resolution (1 km² ) across the high-latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE-focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO₂ sink strength was larger in the boreal biome (observed and predicted average annual NEE -46 and -29 g C m^-2  yr^-1 , respectively) compared to tundra (average annual NEE +10 and -2 g C m^-2  yr^-1 ). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO₂ budget, estimated using the annual NEE ensemble prediction, suggests the high-latitude region was on average an annual CO₂ sink during 1990-2015, although uncertainty remains high.

Identifying dominant environmental predictors of freshwater wetland methane fluxes across diurnal to seasonal time scales

While wetlands are the largest natural source of methane (CH₄ ) to the atmosphere, they represent a large source of uncertainty in the global CH₄ budget due to the complex biogeochemical controls on CH₄ dynamics. Here we present, to our knowledge, the first multi-site synthesis of how predictors of CH₄ fluxes (FCH4) in freshwater wetlands vary across wetland types at diel, multiday (synoptic), and seasonal time scales. We used several statistical approaches (correlation analysis, generalized additive modeling, mutual information, and random forests) in a wavelet-based multi-resolution framework to assess the importance of environmental predictors, nonlinearities and lags on FCH4 across 23 eddy covariance sites. Seasonally, soil and air temperature were dominant predictors of FCH4 at sites with smaller seasonal variation in water table depth (WTD). In contrast, WTD was the dominant predictor for wetlands with smaller variations in temperature (e.g., seasonal tropical/subtropical wetlands). Changes in seasonal FCH4 lagged fluctuations in WTD by ~17 ± 11 days, and lagged air and soil temperature by median values of 8 ± 16 and 5 ± 15 days, respectively. Temperature and WTD were also dominant predictors at the multiday scale. Atmospheric pressure (PA) was another important multiday scale predictor for peat-dominated sites, with drops in PA coinciding with synchronous releases of CH₄ . At the diel scale, synchronous relationships with latent heat flux and vapor pressure deficit suggest that physical processes controlling evaporation and boundary layer mixing exert similar controls on CH₄ volatilization, and suggest the influence of pressurized ventilation in aerenchymatous vegetation. In addition, 1- to 4-h lagged relationships with ecosystem photosynthesis indicate recent carbon substrates, such as root exudates, may also control FCH4. By addressing issues of scale, asynchrony, and nonlinearity, this work improves understanding of the predictors and timing of wetland FCH4 that can inform future studies and models, and help constrain wetland CH₄ emissions.

Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions

Wetland methane (CH4) emissions ([Formula: see text]) are important in global carbon budgets and climate change assessments. Currently, [Formula: see text] projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent [Formula: see text] temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that [Formula: see text] are often controlled by factors beyond temperature. Here, we evaluate the relationship between [Formula: see text] and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between [Formula: see text] and temperature, suggesting larger [Formula: see text] sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.

COSORE: A community database for continuous soil respiration and other soil-atmosphere greenhouse gas flux data

Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO₂ flux, commonly though imprecisely termed soil respiration (R_S ), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency R_S measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open-source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long-term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured R_S , the database design accommodates other soil-atmosphere measurements (e.g. ecosystem respiration, chamber-measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package.

SoilTemp: A global database of near-surface temperature

Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.

Increased high-latitude photosynthetic carbon gain offset by respiration carbon loss during an anomalous warm winter to spring transition

Arctic and boreal ecosystems play an important role in the global carbon (C) budget, and whether they act as a future net C sink or source depends on climate and environmental change. Here, we used complementary in situ measurements, model simulations, and satellite observations to investigate the net carbon dioxide (CO₂ ) seasonal cycle and its climatic and environmental controls across Alaska and northwestern Canada during the anomalously warm winter to spring conditions of 2015 and 2016 (relative to 2010-2014). In the warm spring, we found that photosynthesis was enhanced more than respiration, leading to greater CO₂ uptake. However, photosynthetic enhancement from spring warming was partially offset by greater ecosystem respiration during the preceding anomalously warm winter, resulting in nearly neutral effects on the annual net CO₂ balance. Eddy covariance CO₂ flux measurements showed that air temperature has a primary influence on net CO₂ exchange in winter and spring, while soil moisture has a primary control on net CO₂ exchange in the fall. The net CO₂ exchange was generally more moisture limited in the boreal region than in the Arctic tundra. Our analysis indicates complex seasonal interactions of underlying C cycle processes in response to changing climate and hydrology that may not manifest in changes in net annual CO₂ exchange. Therefore, a better understanding of the seasonal response of C cycle processes may provide important insights for predicting future carbon-climate feedbacks and their consequences on atmospheric CO₂ dynamics in the northern high latitudes.

Pneumothorax associated with nontuberculous mycobacteria: A retrospective study of 69 patients

The incidence of nontuberculous mycobacterial pulmonary disease (NTMPD) is increasing worldwide. Secondary spontaneous pneumothorax occurs as a complication of underlying lung disease and is associated with higher morbidity, mortality, and recurrence than primary spontaneous pneumothorax. We here investigated the clinical features and long-term outcomes of pneumothorax associated with NTMPD.We conducted a retrospective study on consecutive adult patients with pneumothorax associated with NTMPD at Fukujuji Hospital and Keio University Hospital from January 1992 to December 2013. We reviewed the medical records of 69 such patients to obtain clinical characteristics, radiological findings, and long-term outcomes, including pneumothorax recurrence and mortality.The median age of the patients was 68 years; 34 patients were women. The median body mass index was 16.8 kg/m. Underlying pulmonary diseases mainly included chronic obstructive pulmonary disease and pulmonary tuberculosis. On computed tomography, nodules and bronchiectasis were observed in 46 (98%) and 45 (96%) patients, respectively. Consolidation, pleural thickening, interlobular septal thickening, and cavities were most common, and observed in 40 (85%), 40 (85%), 37 (79%), and 36 (77%) patients, respectively. Regarding pneumothorax treatment outcomes, complete and incomplete lung expansion were observed in 49 patients (71%) and 15 patients (22%), respectively. The survival rate after pneumothorax was 48% at 5 years. By the end of the follow-up, 33 patients had died, and the median survival was 4.4 years with a median follow-up period of 1.7 years. The rate of absence of recurrence after the first pneumothorax was 59% at 3 years. By the end of the follow-up, 18 patients had experienced pneumothorax recurrence. Furthermore, 12/18 patients (66%) with recurrent pneumothorax died during the study period. Twenty-three patients (70%) died because of NTMPD progression. Low body mass index (BMI) was a negative prognostic factor for pneumothorax associated with NTMPD in multivariate analysis (HR 0.79, 95% CI 0.64-0.96; P = 0.018)Patients with pneumothorax associated with NTMPD have advanced disease, a high rate of pneumothorax recurrence, and poor prognosis, regardless of the pneumothorax treatment used. Further improvements in early diagnosis of NTMPD and appropriate management in both NTMPD and NTMPD-associated pneumothorax are needed.

Autumn warming reduces the CO2 sink of a black spruce forest in interior Alaska based on a nine-year eddy covariance measurement

Nine years (2003-2011) of carbon dioxide (CO2) flux were measured at a black spruce forest in interior Alaska using the eddy covariance method. Seasonal and interannual variations in the gross primary productivity (GPP) and ecosystem respiration (RE) were associated primarily with air temperature: warmer conditions enhanced GPP and RE. Meanwhile, interannual variation in annual CO2 balance was controlled predominantly by RE, and not GPP. During these 9 years of measurement, the annual CO2 balance shifted from a CO2 sink to a CO2 source, with a 9-year average near zero. The increase in autumn RE was associated with autumn warming and was mostly attributed to a shift in the annual CO2 balance. The increase in autumn air temperature (0.22 °C yr(-1)) during the 9 years of study was 15 times greater than the long-term warming trend between 1905 and 2011 (0.015 °C yr(-1)) due to decadal climate oscillation. This result indicates that most of the shifts in observed CO2 fluxes were associated with decadal climate variability. Because the natural climate varies in a cycle of 10-30 years, a long-term study covering at least one full cycle of decadal climate oscillation is important to quantify the CO2 balance and its interaction with the climate.

Growing season and spatial variations of carbon fluxes of Arctic and boreal ecosystems in Alaska (USA)

To better understand the spatial and temporal dynamics of CO2 exchange between Arctic ecosystems and the atmosphere, we synthesized CO2 flux data, measured in eight Arctic tundra and five boreal ecosystems across Alaska (USA) and identified growing season and spatial variations of the fluxes and environmental controlling factors. For the period examined, all of the boreal and seven of the eight Arctic tundra ecosystems acted as CO2 sinks during the growing season. Seasonal patterns of the CO2 fluxes were mostly determined by air temperature, except ecosystem respiration (RE) of tundra. For the tundra ecosystems, the spatial variation of gross primary productivity (GPP) and net CO2 sink strength were explained by growing season length, whereas RE increased with growing degree days. For boreal ecosystems, the spatial variation of net CO2 sink strength was mostly determined by recovery of GPP from fire disturbance. Satellite-derived leaf area index (LAI) was a better index to explain the spatial variations of GPP and NEE of the ecosystems in Alaska than were the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Multiple regression models using growing degree days, growing season length, and satellite-derived LAI explained much of the spatial variation in GPP and net CO2 exchange among the tundra and boreal ecosystems. The high sensitivity of the sink strength to growing season length indicated that the tundra ecosystem could increase CO2 sink strength under expected future warming, whereas ecosystem compositions associated with fire disturbance could play a major role in carbon release from boreal ecosystems.

A female-specific desaturase gene responsible for diene hydrocarbon biosynthesis and courtship behaviour in Drosophila melanogaster

Drosophila melanogaster shows sexually dimorphic cuticular hydrocarbons, with monoenes produced in males and dienes produced in females. Here we describe a female-specific desaturase gene, desatF. RNAi knock-down led to a dramatic decrease in female dienes and increase in monoenes paralleled with an increase in copulation latency and a decrease in courtship index and copulation attempts by the males. The desatF gene was also expressed in females from D. sechellia, rich in dienes, but not D. simulans, which produce only monoenes. When hydrocarbons were feminized in D. melanogaster males by targeted expression of the transformer gene, the expression of desatF occurred. These results strongly suggest that desatF is a crucial enzyme for female pheromone biosynthesis and courtship behaviour in D. melanogaster.

Effect of human hydrosalpinx fluid on in vitro mouse embryogenesis

OBJECTIVE

Women with hydrosalpinx have an unfavorable pregnancy rate. As one approach to elucidate the effect of hydrosalpinx on uterine tubal functioning, we examined the effect of hydrosalpinx fluid on early embryo development in mice.

METHODS

Hyperovulation was induced in ICR mice, and late 2-cell-stage embryos were harvested 42 hours after administration of human chorionic gonadotropin (hCG). Hydrosalpinx fluid was obtained from patients during surgery after informed consent was obtained. The embryos were cultured in 3 culture fluids: (1) mBWW medium containing 0.3% bovine serum albumin (positive-control medium) (BSA), (2) Ca2+, Mg2+-free phosphate buffered saline (negative-control medium) (PBS), and (3) 100% human hydrosalpinx fluid. The developmental status of the embryos 120 hours after hCG administration was examined.

RESULTS

Embryogenesis from a 2-cell-stage embryo to a blastocyst was observed in 98.3% (118/120) of the embryos cultured in the mBWW medium, in 0% (0/120) of the embryos cultured in PBS, and in 98.3% (118/120) of the embryos cultured in 100% human hydrosalpinx fluid.

CONCLUSION

In the micro-environment of human hydrosalpinx fluid, late 2-cell embryos of ICR mice developed normally to blastocysts. The present results also suggest that non-species-specific embryogenetic factors might be present in human hydrosalpinx fluid.

Cardioprotective effects of quinapril after myocardial infarction in hypertensive rats

Although angiotensin-converting enzyme inhibitors are beneficial for patients with congestive heart failure, the appropriate timing and dosage in acute myocardial infarction are still controversial. We examined the hemodynamic effects of quinapril administered before acute myocardial infarction in spontaneously hypertensive rats (SHR). Quinapril (10 mg/kg per day in drinking water) was started 1 week before infarction and continued for 4 weeks after infarction (total duration 5 weeks). The hemodynamic parameters were evaluated by cardiac catheterization 4 weeks after coronary ligation. Sham-operated SHR served as controls. After infarction, left ventricular end-diastolic and right atrial pressures were increased (P < 0.01) and blood pressure and cardiac index were decreased (P < 0.01); the magnitude of blood pressure reduction was similar in the treated and untreated rats with infarction. Quinapril improved these hemodynamic parameters significantly and decreased left and right ventricular weight. These results suggest that a prior treatment with quinapril in SHR with acute myocardial infarction is hemodynamically beneficial.

Ovulation and the suppression of mating in Drosophila melanogaster females: behavioral basis

Virgin females of Drosophila melanogaster that are ectopically expressing the sex-peptide gene show a high level of ovulation and are unreceptive to males. However, if they are genetically deprived of eggs, receptivity is considerably restored (Fuyama, 1995). These females, whether they have eggs or not, extrude their ovipositors toward courting males as frequently as do fertilized females. However, this rejection behavior was ineffective in suppressing male courtship. Of females with eggs, about half of them could suppress male courtship. Females lacking eggs could not suppress male courtship and continued to elicit vigorous courtship. This difference seems to account for the increased mating frequency in sterilized females. Courtship behavior by mutant males defective in olfaction or learning suggested that females are capable of repelling males by emitting a volatile pheromone(s) with an inhibitory effect on male courtship.

[Internal carotid artery occlusion related to seat belt shoulder strap: report of two cases]

Two cases of traumatic internal carotid artery occlusion probably related to the seat belt shoulder strap are reported. Case 1. A 20-year-old woman was driving and was struck on the right front side of her car by another car. There were neither bruises, abrasions on her neck, nor weakness in her extremities. About 4 hours later, she developed left hemiplegia, and CT scan taken on the following day revealed low density areas in the capsulostriatal area on the right. The right carotid angiography revealed occlusion of the internal carotid artery about 3 cm distal to the bifurcation. Case 2. A 43-year-old man was driving and was struck on the front of his car by a hard iron railing. He sustained a sternum fracture, but there was no disturbance of consciousness or paresis of the extremities. His neck was unremarkable externally. About 50 days later, he developed left hemiplegia. CT scan and MRI revealed a massive infarction in the distribution of the right middle cerebral artery territories. The carotid angiography revealed occlusion of the right internal carotid artery about 3 cm distal to the bifurcation. In each cases, the driver was wearing a three-point shoulder seatbelt when the car was struck on the front or on the right front. Previous experimental studies have revealed in these situations the neck is flexed right anteriorly, and then quickly overextended left posteriorly. The overextension of the neck probably injured the intima of the internal carotid artery ipsilateral to the shoulder fixed in the seatbelt, resulting in the subsequent occlusion by a thrombus.

Comparable effects of angiotensin II and converting enzyme blockade on hemodynamics and cardiac hypertrophy in spontaneously hypertensive rats

Angiotensin-converting enzyme inhibitors may regress left ventricular hypertrophy (LVH) without decreasing blood pressure (BP). The aim of the present study was to compare the effects of low and high doses of lisinopril and the angiotensin II receptor antagonist TCV116 (TCV) on LVH and hemodynamics in spontaneously hypertensive rats (SHR). Lisinopril (0.5 and 3 mg/kg per day) and TCV (0.3 mg/kg per day) were given to 8-week-old male SHR daily for 2 weeks. Untreated SHR and Wistar-Kyoto rats (WKY) served as controls. Untreated SHR had a greater left ventricular (LV) weight than WKY (p < 0.01). Lisinopril (3 mg/kg per day) decreased both LV weight and BP. Lisinopril (0.5 mg/kg per day) significantly decreased LV weight, but not BP. In contrast, although TCV significantly decreased BP, LVH was not suppressed. Renal blood flow (RBF) in untreated SHR was less than that in WKY (p < 0.05), but was increased with either lisinopril (3 mg/kg per day)-treated rats (p< 0.05). These findings suggest that factors other than afterload reduction play a role in the regression of LVH with lisinopril, whereas a longer duration of treatment and/or a higher dose may be necessary with TCV. Despite the decrease in BP, TCV normalized RBF in SHR, perhaps due to the blockade of renal angiotensin II.

Left ventricular function of the heart regressed by nifedipine in spontaneously hypertensive rats

Left ventricular (LV) performance of the pharmacologically regressed heart in hypertension is still unclear. We compared LV function of the heart regressed by nifedipine with that of the hypertrophied heart in spontaneously hypertensive rats (SHR). Nifedipine (30 mg/kg/day in food) was given to 15-week-old male SHR for 20 weeks (n = 12). Age- and sex-matched SHR served as controls (n = 12). LV catheterization was performed using a micromanometer and cardiac output was determined by the thermodilution method. Hemodynamic studies were performed after washout of nifedipine (24 h), when blood pressure had returned to the untreated level. Peak pumping ability was assessed during acute volume loading with saline. Nifedipine significantly decreased blood pressure in conscious animals (222 +/- 11 to 201 +/- 12 mmHg, p < 0.01) and reduced LV weight (1.20 +/- 0.07 to 1.07 +/- 0.05g, p < 0.01). After washout of nifedipine, LV systolic and end-diastolic pressures, dp/dtmax and cardiac output determined under pentobarbital anesthesia were similar in the treated and untreated groups. Peak pumping ability during acute preload elevation was also similar in the 2 groups. Plasma norepinephrine was unaltered, and plasma renin activity was significantly lower in the treated rats (p < 0.05). These results indicate that nifedipine regressed LVH with a minimal reduction of blood pressure and without evidence of neurohumoral activation or volume retention. In conclusion, LV function of the heart regressed by nifedipine was preserved after a spontaneous rise in blood pressure and during acute preload elevation.

Converting enzyme inhibition improves congestion and survival in hypertensive rats with high-output heart failure

The effects of angiotensin-converting enzyme (ACE) inhibitors in high-output heart failure have not yet been well established. We evaluated the effects of lisinopril (3 mg/kg/day) on hemodynamics, neurohormones, and survival in 10-week-old spontaneously hypertensive rats (SHR) with aortocaval fistula. Sham-operated treated and untreated SHR served as controls. Cardiac output (CO) was determined by thermodilution method, and renal blood flow (RBF) was assessed by laser-Doppler flowmetry. In sham-operated SHR, 2-week treatment with lisinopril decreased blood pressure (BP), left ventricular (LV) weight, and total peripheral resistance (TPR) (p < 0.01 each) and increased RBF and plasma renin activity (PRA) (both p < 0.05); CO and LV end-diastolic pressure (LVEDP) were unchanged. Fistula creation induced biventricular hypertrophy and high-output heart failure [increased LVEDP, CO, pulse pressure, and plasma norepinephrine (NE) and decreased RBF] with congestive signs (ascites, tachypnea). Lisinopril decreased LVEDP (p < 0.01), increased RBF, prolonged survival (both p < 0.05), and prevented ascites (0 vs. 46%) and increased PRA (p < 0.05) and attenuated the increase in plasma NE. Heart weight, BP, and CO were not affected by lisinopril. Thus, lisinopril ameliorated congestion and improved survival in SHR with fistula without compromising cardiorenal hemodynamics. Venous and renal dilatation and attenuation of vasoconstrictive systems may have contributed to the beneficial effects.

Effects of renal denervation on pressure-natriuresis in spontaneously hypertensive rats

To investigate the role of renal sympathetic nerve activity (RSNA) under developing and established hypertension, renal function was studied in chronically renal-denervated and sham-operated male spontaneously hypertensive rats (SHR) and control Wistar Kyoto rats (WKY) at 8 (early hypertensive) and 22 (established hypertensive) weeks of age. To further characterize the renal pressure-natriuresis-diuresis relationship in SHR, renal perfusion pressure (RPP) was reduced by aortic constriction to the level seen in age-matched WKY and the same studies were repeated. After denervation, urinary sodium excretion (UNaV), fractional excretion of sodium (FENa) and urine flow (UF) were increased in 8-week-old SHR (p < 0.01). With the exceptions of UNaV and FENa in denervated 8-week-old SHR, renal cortical blood flow, glomerular filtration rate, UF, UNaV and FENa decreased with the reduction of RPP in all of the SHR groups. These results suggest that RSNA significantly influences renal sodium and fluid handling, thus contributing to the shifting of the arterial pressure-renal sodium excretion curve to the right along the pressure axis and/or to an increase in the steepness of the relationship in 8-week-old SHR. There appeared to be a marked difference in renal sodium handling between 8- and 22-week-old SHR.

Long-term alpha 1 blockade does not reverse cardiac hypertrophy in spontaneously hypertensive rats

Not all antihypertensive drugs induce regression of left ventricular (LV) hypertrophy in hypertension, although they may equally lower blood pressure. The effects of alpha 1-blockers on regression have been inconsistent. In this study, bunazosin, a selective alpha 1-blocker, (15 mg/kg/day in food) was given to male spontaneously hypertensive rats (SHR) from 15 to 35 weeks of age to evaluate its effects on cardiac hypertrophy, hemodynamics, and neurohumoral factors. Age- and sex-matched SHR served as controls. LV function and cardiac output were determined by a micromanometer and thermodilution, respectively. Bunazosin significantly decreased blood pressure in conscious rats (from 209 to 192 mmHg, p < 0.01) but did not reduce LV mass. Heart rate, LV end-diastolic pressure, dp/dtmax, and cardiac output were similar in the 2 groups. Plasma renin activity was unaltered but plasma norepinephrine levels were higher in the treated rats (p < 0.05). Thus, bunazosin produced a significant relative reduction of blood pressure but did not reverse LV hypertrophy in SHR. Inadequate afterload reduction (8%) due to severe hypertension (> 200 mmHg) may explain the absence of regression. The rise of plasma norepinephrine levels may also offset the beneficial effects of bunazosin.

Haemodynamic and neurohumoral changes in spontaneously hypertensive rats with aortocaval fistulae

1. Our aim was to evaluate the effects of an aortocaval fistula (1 mm) on cardiorenal haemodynamics, cardiac hypertrophy and neurohumoral factors in spontaneously hypertensive rats and to compare the results with those observed in Wistar rats at 2 weeks after fistulae placement. Sham-operated spontaneously hypertensive rats and Wistar rats served as controls. 2. Heart weight was significantly increased in spontaneously hypertensive rats (34%) and in Wistar rats (43%) at 2 weeks after fistula creation. Left ventricular systolic pressure and dp/dtmax. were significantly decreased (both P < 0.01) in spontaneously hypertensive rats with fistulae which had higher left ventricular end-diastolic pressure than Wistar rats with fistulae (P < 0.01). Signs of circulatory congestion (ascites, tachypnoea, prostration) were observed only in the overloaded spontaneously hypertensive rats (45%). Cardiac index was comparably increased in both fistulae groups due to an increase in stroke index, since heart rate was not increased. 3. Fistulae placement decreased renal blood flow and kidney weight, and increased blood urea nitrogen to a greater degree in spontaneously hypertensive rats (all P < 0.05); serum creatinine levels were unaltered. Plasma noradrenaline concentration was increased in spontaneously hypertensive rats with fistulae (P < 0.05), whereas plasma renin activity was not changed. 4. Thus, spontaneously hypertensive rats with fistulae developed overt haemodynamic signs of high-output heart failure with frequent ascites and dyspnoea, whereas most of these findings were milder or absent in Wistar rats. This model provides an opportunity to evaluate the pathophysiological and pharmacological responses in high-output heart failure.

Hemodynamic and neurohumoral responses to exercise in patients with congestive heart failure

Hemodynamic and neurohumoral responses to supine bicycle exercise were evaluated in 16 patients with congestive heart failure (New York Heart Association functional class II-III) and in 8 normal controls. We determined cardiac output by the dye-dilution method, and forearm hemodynamics by plethysmography. The patients had lower resting cardiac and stroke indexes (p < 0.05) than the normal controls. During exercise, the increase in the cardiac index due to an increase in heart rate, was less than that in the controls. Resting and exercise systemic vascular resistance indices were higher in the patients (p < 0.05). The patients had lower resting forearm blood flow and higher forearm vascular resistance (p < 0.05), and the increases during exercise were comparable in the 2 groups. However, forearm venous tone and venous pressure increased more in the patients (p < 0.05). Exercise duration was shorter in the patients (p < 0.01). Resting plasma angiotensin II and norepinephrine were similar in the 2 groups, but plasma 6-keto-prostaglandin F1 alpha and atrial natriuretic peptide were higher in the patients. During exercise, all of these neurohumoral parameters rose more in the patients than in the controls (p < 0.05). Thus, the patients exhibited impaired central and peripheral hemodynamics both at rest and during exercise. The excessive exercise responses of all of the neurohumoral factors suggest that both vasoconstrictor and vasodilator systems are activated in heart failure.

Lisinopril reduces cardiac hypertrophy and mortality in rats with aortocaval fistula

We evaluated the effects of lisinopril (1 mg/kg per day) on hemodynamics, cardiac hypertrophy, and neurohumoral factors in Wistar rats with an abdominal aortocaval fistula. After 4 weeks of treatment, the results were compared with values obtained for untreated rats with a fistula and for sham-operated rats. Volume loading induced biventricular hypertrophy, hemodynamic signs of high-output heart failure (increased cardiac output, left ventricular end-diastolic pressure, and pulse pressure), and impaired renal function (decreased renal blood flow and kidney weight; increased blood urea nitrogen). Lisinopril did not affect these cardiorenal hemodynamics, but decreased left ventricular mass and mortality rate (both P < 0.05). Lisinopril attenuated the increase in plasma norepinephrine, and increased plasma renin activity (both P < 0.05). Thus, lisinopril reduced left ventricular mass and mortality in rats with high-output heart failure without changing the cardiorenal hemodynamics. Neurohumoral inhibition may play a role in the beneficial effects of lisinopril.

Marked increase in plasma interleukin-6 in burn patients

We measured the levels of interleukin-6 in plasma samples from 18 consecutive burn patients, including three lethal cases, during the early postburn period. In survivors burn injury caused initial increases in interleukin-6 levels that peaked at 6 hours after burn; this was significantly higher than interleukin-6 levels in normal controls (718 +/- 216 vs 70 +/- 4 pg/ml; p < 0.01). The increment in nonsurvivors was even more prominent (11,554 +/- 4,407 pg/ml; p < 0.01). The peak interleukin-6 levels at 6 hours correlated with total burn surface area (r = 0.65, p < 0.025), and tended to be higher in patients with inhalation injury. These data provide evidence that burn injury causes rapid release of interleukin-6 according to the severity of the injury. We also measured acute-phase reactants including fibrinogen, alpha 1-antitrypsin, C1 inhibitor, and alpha 2-plasmin inhibitor. After initial declines, these four proteins increased rapidly in survivors. In addition, the peak interleukin-6 levels correlated well with the increases in fibrinogen (p < 0.025), alpha 1-antitrypsin (p < 0.01), C1 inhibitor (p < 0.01), and alpha 2-plasmin inhibitor (p < 0.0001). In contrast, despite the marked increase in interleukin-6, the levels of acute phase proteins in nonsurvivors remained low. Based on these observations, we suggest that interleukin-6 is released as an alarm signal and has a role for the wound healing in burn patients, and that the levels of interleukin-6 after injury is an indicator of the severity of burn.

Effects of lisinopril upon cardiac hypertrophy, central and peripheral hemodynamics and neurohumoral factors in spontaneously hypertensive rats

OBJECTIVE

Left ventricular function (LVF) after reversal of left ventricular hypertrophy (LVH) with antihypertensive therapy is still controversial. The present study was undertaken in spontaneously hypertensive rats (SHR) to determine whether LVF of the regressed heart with lisinopril is normally maintained.

DESIGN

We compared cardiac function of SHR after reversal of LVH induced by lisinopril with that observed in control SHR and also with effects after a 4-week washout period.

METHODS

Administration of lisinopril began at 15 weeks of age and continued for 20 weeks. Cardiac index, renal blood flow, leg muscle blood flow, plasma renin activity, atrial natriuretic peptide level, and norepinephrine concentration were determined.

RESULTS

Lisinopril decreased body weight, blood pressure and left ventricular weight and increased leg muscle blood flow; cardiac index and renal blood flow were unaltered. Although norepinephrine concentration was unchanged, plasma renin activity increased and atrial natriuretic peptide decreased in treated SHR. Peak left ventricular pumping ability during volume loading was comparable in the two groups. After a 4-week washout period, left ventricular mass and blood pressure increased but remained lower than controls; cardiac index at rest and during volume loading was similar in the two groups.

CONCLUSIONS

These data indicate that LVF of the regressed heart induced by lisinopril was well preserved at rest, during volume loading and also after spontaneous recurrence of hypertension in SHR.

Nifedipine in divided doses does not reverse left ventricular hypertrophy in spontaneously hypertensive rats

This study investigated whether nifedipine administered in divided daily doses would diminish left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHR). We administered nifedipine (12 mg/kg/day) in 3 divided doses by gastric gavage to 15-week-old male SHR (n = 10) for 4 weeks. Age- and sex-matched SHR served as controls (n = 10). Left ventricular (LV) function was evaluated by LV catheterization and cardiac output was determined by the thermodilution method. Plasma renin activity (PRA) and plasma norepinephrine levels were measured. Nifedipine significantly decreased blood pressure (p less than 0.01), shortened time constant T (p less than 0.05), and increased cardiac output (p less than 0.05). Nifedipine did not impair the LV systolic and diastolic indices during acute afterload elevation with angiotensin II. LV weight was similar in the 2 groups of rats. While PRA was unaltered, plasma norepinephrine levels were higher in the nifedipine-treated rats (p less than 0.05). These data indicate that nifedipine in 3 divided doses reduced blood pressure in SHR without compromising cardiac function but did not reverse LVH. The short hypotensive duration of nifedipine and its enhancement of sympathetic nervous activity may be responsible for the failure to reverse LVH, despite adequate blood pressure control.

[Disseminated intravascular coagulation in the early stage after severe burn: the role of excessive thrombin generation]

The pathogenesis of disseminated intravascular coagulation (DIC) in the early stage after burn injury remains still unclear. We investigated 12 burn injured patients by serial determination of anti-thrombin III (AT-III) activities and thrombin-antithrombin III complex (TAT) levels. Of these patients 4 developed DIC (DIC group) and the others had no hematological complications (non-DIC group). The mean levels of TAT increased markedly and peaked at 6 hr; the increment being more pronounced in DIC group (p less than 0.001). A significant correlation was recognized between TAT and Burn Index (r = 0.871, p less than 0.001). We also observed low AT-III activities those inversely related to Burn Index (r = 0.875, p less than 0.001), whereas closely correlated with serum albumin levels (r = 0.864, p less than 0.001), suggesting that this depression might be caused by both massive infusion and shifts of plasma into the extravascular space rather than consumption. These findings suggest that massive thrombin generation and decrease of anticoagulant activity, correlated to the severity of burns, might concurrently develop. Non-DIC group may remain to latent activation of coagulation cascade where anticoagulants could inactivate thrombin generated. This compensatory mechanism may fail in severe burn patients who have Burn Index of more than 90, developing DIC with high levels of TAT (316.3 +/- 104.5 ng/ml) and low AT-III activities (19.5 +/- 8.7%).

[Driver identification of the motorcycle in motorcycle/car accidents]

A series of motorcycle/car collision experiments and in-depth investigations involving motorcycle/car accidents with two riders were carried out in order to study the difference in behavior and injuries between the driver and the passenger of the motorcycle during a collision, and to provide general data for identifying their seat positions on the motorcycle in traffic accidents. In all the tests, two Hybrid II dummies were seated on the double seats of the motorcycle as riders. The motorcycle collided against the front door, front end or rear door of the passenger car at a speed of 50 km/h, at impact angles of 60 degrees, 90 degrees or 120 degrees. The speeds of the passenger car were tested at 0 km/h or 25 km/h. With different speeds of vehicles and different impact angles, the difference in rider behavior between the driver and the passenger was distinctly verified by analysis of high speed films. It is possible to distinguish the driver's injuries from the passenger's. The abrasion and/or contusions in the chest, face and groin area were severe for the drivers, but less serious for the passengers. The typical injuries of the driver can be expected in terms of the rider behavior during collision from 25 ms to about 150 ms after starting contact. The data and information can be used to clarify the question of who was driving in accident reconstruction.

[A case of severe tetanus associated with sympathetic overactivity]

A case of severe tetanus showing clinical features compatible with sympathetic overactivity (SOA) is reported. A 64-year-old man was admitted to our hospital 6 days after injury. The clinical signs of SOA developed on the second day in ICU. Through the clinical investigation of this case, we found out and insisted on some new concepts about the clinical features of SOA. 1. Lability of arterial pressure is parallel to that of catecholamine level in serum. 2. Two different types in SOA were found. One is dominantly lable type of Adrenaline and another is of Noradrenaline. 3. Drawing a sharp line between 2 types by assessment of circulatory data from Swan-Ganz catheter is significant for deciding therapeutic lines.

[Effect of active oxygen on cytoplasmic Ca2+ sequestration mechanism]

Effects of the active oxygen on the extrusion mechanism of once-increased cytoplasmic Ca2+, which causes various physiological phenomena, were investigated using different kinds of culture cells. First we found that, in response to stimulation with vitamin K (VK), various culture cells showed a decrease in cytoplasmic Ca2+ concentration. On the presumption that this phenomenon might be related to the oxidizing action of VK, we performed the same experiments using oxidizing agents such as H2O2 or KO2. They also showed a decrease in cytoplasmic Ca2+ concentration. Furthermore, they suppressed the increase of cytoplasmic Ca2+ by vasopressin. It would be inferred from these results that the active oxygen may act upon some site of the cellular signal transduction system of cell membrane to lower the cytoplasmic Ca2+ level.

Cardiorenal effects of an orally active dopamine prodrug (TA-870) in patients with congestive heart failure

The effects of TA-870, a newly synthesized orally active dopamine prodrug, on the cardiorenal functions were investigated in 12 patients with severe chronic congestive heart failure. A single oral dose of TA-870 (1,200 mg) improved left ventricular fractional shortening and mean circumferential velocity on M-mode echocardiography (p less than 0.01 for both). Renal plasma flow and glomerular filtration rate improved with TA-870 (p less than 0.01 and p less than 0.05, respectively); urine volume and sodium excretion increased (p less than 0.01 for both). Blood pressure and heart rate did not change during the 4-h experimental period. Mean plasma free dopamine levels peaked 1 h after dosing. These data suggest that the cardiorenal effects of oral TA-870 are comparable with those of continuous intravenous injections of dopamine. Thus, TA-870 appears to be a useful alternative drug to intravenous dopamine.

[A clinical study of pulmonary edema on paraquat poisoning by double indicator dilution method using heat and sodium]

We studied the formation of pulmonary edema on 9 patients with paraquat poisoning using thermal-sodium double indicator dilution method for the measurement of lung water. In survivors group (n = 4) extravascular thermal volume (EVTV) was not almost changes. In non-survivors group (n = 5) EVTV increased about three times as much as that in survivors group on 32 hours after admission. EVTV was correlated with PCP-PCOP in both survivors group and non-survivors group (n = 64, r = 0.665, p less than 0.01). But EVTV in non-survivors group was higher than that in survivors group within same PCP-PCOP. In non-survivors group delta EVTV/delta (PCP-PCOP) in 24 hours after admission was correlated with initial PCP-PCOP (r = 0.984, p less than 0.01). We propose that the formation of pulmonary edema on paraquat poisoning is mainly due to the increased capillary permeability, influenced by the increased pressure gradient of capillary barrier.